15 CFR 230.1 - Introduction.

Code of Federal Regulations, 2011 CFR

2011-01-01

... base. NIST Special Publication 260, “Catalog of NIST Standard Reference Materials,” lists and describes the SRM's issued by NIST. SP 260 is periodically revised to include new SRM's and eliminate those that...

15 CFR 230.1 - Introduction.

Code of Federal Regulations, 2014 CFR

2014-01-01

... base. NIST Special Publication 260, “Catalog of NIST Standard Reference Materials,” lists and describes the SRM's issued by NIST. SP 260 is periodically revised to include new SRM's and eliminate those that...

15 CFR 230.1 - Introduction.

Code of Federal Regulations, 2012 CFR

2012-01-01

... base. NIST Special Publication 260, “Catalog of NIST Standard Reference Materials,” lists and describes the SRM's issued by NIST. SP 260 is periodically revised to include new SRM's and eliminate those that...

15 CFR 230.1 - Introduction.

Code of Federal Regulations, 2010 CFR

2010-01-01

... base. NIST Special Publication 260, “Catalog of NIST Standard Reference Materials,” lists and describes the SRM's issued by NIST. SP 260 is periodically revised to include new SRM's and eliminate those that...

15 CFR 230.1 - Introduction.

Code of Federal Regulations, 2013 CFR

2013-01-01

... base. NIST Special Publication 260, “Catalog of NIST Standard Reference Materials,” lists and describes the SRM's issued by NIST. SP 260 is periodically revised to include new SRM's and eliminate those that...

Preparation of Reference Material 8504, Transformer Oil

PubMed Central

Poster, Dianne L.; Schantz, Michele M.; Wise, Stephen A.

2005-01-01

A new reference material (RM), RM 8504, has been prepared for use as a diluent oil with Aroclors in transformer oil Standard Reference Materials (SRMs) 3075 to 3080 and SRM 3090 when developing and validating methods for the determination of polychlorinated biphenyls (PCBs) as Aroclors in transformer oil or similar matrices. SRMs 3075-3080 and SRM 3090 consist of individual Aroclors in the same transformer oil that was used to prepare RM 8504. A unit of RM 8504 consists of one bottle containing approximately 100 mL of transformer oil. No additional constituents have been added to the oil. PMID:27308183

Determination of polychlorinated biphenyl congeners and chlorinated pesticides in a fish tissue standard reference material.

PubMed

Poster, Dianne L; Kucklick, John R; Schantz, Michele M; Porter, Barbara J; Leigh, Stefan D; Wise, Stephen A

2003-01-01

The concentrations of a wide range of polychlorinated biphenyl congeners (PCBs) and chlorinated pesticides in a fish tissue Standard Reference Material (SRM) have been determined using multiple methods of analysis. This material, SRM 1946, Lake Superior Fish Tissue, was recently issued by the National Institute of Standards and Technology (NIST) and complements a suite of marine environmental natural-matrix SRMs that are currently available from NIST for the determination of organic contaminants such as aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), PCBs, and chlorinated pesticides. SRM 1946 is a fresh tissue homogenate (frozen) prepared from filleted adult lake trout (Salvelinus namaycush namaycush) collected from the Apostle Islands region of Lake Superior. SRM 1946 has certified and reference concentrations for PCB congeners, including the three non- ortho PCB congeners, and chlorinated pesticides. Certified concentrations are available for 30 PCB congeners and 15 chlorinated pesticides. Reference concentrations are available for 12 PCB congeners and 2 chlorinated pesticides. In addition, SRM 1946 is characterized for additional chemical constituents and properties: fatty acids, extractable fat, methylmercury, total mercury, selected trace elements, proximates, and caloric content. The characterization of chlorinated compounds is described in this paper with an emphasis on the approach used for the certification of the concentrations of PCB congeners and chlorinated pesticides. The PCB congener and chlorinated pesticide data are also compared to concentrations in other marine natural-matrix reference materials available from NIST (fish oil, mussel tissue, whale blubber, and a second fresh frozen fish tissue homogenate prepared from filleted adult lake trout collected from Lake Michigan) and from other organizations such as the National Research Council Canada (ground whole carp), the International Atomic Energy Agency (fish homogenate), and the European Commission Joint Research Centre [fish oils (cod and mackerel) and mussel tissue].

New NIST sediment SRM for inorganic analysis.

PubMed

Zeisler, Rolf

2004-03-01

NIST maintains a portfolio of more than 1300 standard reference materials (SRM), more than a third of these relating to measurements in the biological and environmental fields. As part of the continuous renewal and replacement efforts, a set of new marine sediments has been recently developed covering organic and inorganic determinations. This paper describes the steps taken in sample preparation, homogeneity assay, and analytical characterization and certification with specific emphasis on SRM 2702 inorganics in marine sediment. Neutron activation analysis showed the SRM to be highly homogeneous, opening the possibility for use with solid sampling techniques. The certificate provides certified mass fraction values for 25 elements, reference values for eight elements, and information values for 11 elements, covering most of the priority pollutants with small uncertainties of only several percent relative. The values were obtained by combining results from different laboratories and techniques using a Bayesian statistical model. An intercomparison carried out in field laboratories with the material before certification illustrates a high commutability of this SRM.

Determination of fat-soluble vitamins and carotenoids in standard reference material 3280 multivitamin/multielement tablets by liquid chromatography with absorbance detection.

PubMed

Thomas, Jeanice B; Sharpless, Katherine E; Yen, James H; Rimmer, Catherine A

2011-01-01

The concentrations of selected fat-soluble vitamins and carotenoids in Standard Reference Material (SRM) 3280 Multivitamin/Multielement Tablets have been determined by two independent LC methods, with measurements performed by the National Institute of Standards and Technology (NIST). This SRM has been prepared as part of a collaborative effort between NIST and the National Institutes of Health Office of Dietary Supplements. The SRM is also intended to support the Dietary Supplement Ingredient Database that is being established by the U.S. Department of Agriculture. The methods used at NIST to determine the concentration levels of vitamins A and E, and beta-carotene in the SRM used RPLC with absorbance detection. The relative precision of these methods ranged from 2 to 8% for the analytes measured. SRM 3280 is primarily intended for use in validating analytical methods for the determination of selected vitamins, carotenoids, and elements in multivitamin/multielement tablets and similar matrixes.

Determination of perfluorinated alkyl acid concentrations in biological standard reference materials.

PubMed

Reiner, Jessica L; O'Connell, Steven G; Butt, Craig M; Mabury, Scott A; Small, Jeff M; De Silva, Amila O; Muir, Derek C G; Delinsky, Amy D; Strynar, Mark J; Lindstrom, Andrew B; Reagen, William K; Malinsky, Michelle; Schäfer, Sandra; Kwadijk, Christiaan J A F; Schantz, Michele M; Keller, Jennifer M

2012-11-01

Standard reference materials (SRMs) are homogeneous, well-characterized materials used to validate measurements and improve the quality of analytical data. The National Institute of Standards and Technology (NIST) has a wide range of SRMs that have mass fraction values assigned for legacy pollutants. These SRMs can also serve as test materials for method development, method validation, and measurement for contaminants of emerging concern. Because inter-laboratory comparison studies have revealed substantial variability of measurements of perfluoroalkyl acids (PFAAs), future analytical measurements will benefit from determination of consensus values for PFAAs in SRMs to provide a means to demonstrate method-specific performance. To that end, NIST, in collaboration with other groups, has been measuring concentrations of PFAAs in a variety of SRMs. Here we report levels of PFAAs and perfluorooctane sulfonamide (PFOSA) determined in four biological SRMs: fish tissue (SRM 1946 Lake Superior Fish Tissue, SRM 1947 Lake Michigan Fish Tissue), bovine liver (SRM 1577c), and mussel tissue (SRM 2974a). We also report concentrations for three in-house quality-control materials: beluga whale liver, pygmy sperm whale liver, and white-sided dolphin liver. Measurements in SRMs show an array of PFAAs, with perfluorooctane sulfonate (PFOS) being the most frequently detected. Reference and information values are reported for PFAAs measured in these biological SRMs.

Long-term stability and temporal trends of organic contaminants in four collections of mussel tissue frozen standard reference materials.

PubMed

Schantz, Michele M; Pugh, Rebecca S; Pol, Stacy S Vander; Wise, Stephen A

2015-04-01

The stability of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and chlorinated pesticides in frozen mussel tissue Standard Reference Materials (SRMs) stored at -80 °C was assessed by analyzing samples of SRM 1974, SRM 1974a, and SRM 1974b Organics in Mussel Tissue (Mytilus edulis) periodically over 25 y, 20 y, and 12 y, respectively. The most recent analyses were performed during the certification of the fourth release of this material, SRM 1974c. Results indicate the concentrations of these persistent organic pollutants have not changed during storage at -80 °C. In addition, brominated diphenyl ethers (BDEs) were quantified in each of the materials during this study. The stability information is important for on-going monitoring studies collecting large quantities of samples for future analyses (i.e., formally established specimen banking programs). Since all four mussel tissue SRMs were prepared from mussels collected at the same site in Dorchester Bay, MA, USA, the results provide a temporal trend study for these contaminants over a 17 year period (1987 to 2004).

Characterization of NIST human mitochondrial DNA SRM-2392 and SRM-2392-I standard reference materials by next generation sequencing.

PubMed

Riman, Sarah; Kiesler, Kevin M; Borsuk, Lisa A; Vallone, Peter M

2017-07-01

Standard Reference Materials SRM 2392 and 2392-I are intended to provide quality control when amplifying and sequencing human mitochondrial genome sequences. The National Institute of Standards and Technology (NIST) offers these SRMs to laboratories performing DNA-based forensic human identification, molecular diagnosis of mitochondrial diseases, mutation detection, evolutionary anthropology, and genetic genealogy. The entire mtGenome (∼16569bp) of SRM 2392 and 2392-I have previously been characterized at NIST by Sanger sequencing. Herein, we used the sensitivity, specificity, and accuracy offered by next generation sequencing (NGS) to: (1) re-sequence the certified values of the SRM 2392 and 2392-I; (2) confirm Sanger data with a high coverage new sequencing technology; (3) detect lower level heteroplasmies (<20%); and thus (4) support mitochondrial sequencing communities in the adoption of NGS methods. To obtain a consensus sequence for the SRMs as well as identify and control any bias, sequencing was performed using two NGS platforms and data was analyzed using different bioinformatics pipelines. Our results confirm five low level heteroplasmy sites that were not previously observed with Sanger sequencing: three sites in the GM09947A template in SRM 2392 and two sites in the HL-60 template in SRM 2392-I. Copyright © 2017 Elsevier B.V. All rights reserved.

Polyfluorinated substances in abiotic standard reference ...

EPA Pesticide Factsheets

The National Institute of Standards and Technology (NIST) has a wide range of Standard Reference Materials (SRMs) which have values assigned for legacy organic pollutants and toxic elements. Existing SRMs serve as homogenous materials that can be used for method development, method validation, and measurement for contaminants that are now of concern. NIST and multiple groups have been measuring the mass fraction of a group of emerging contaminants, polyfluorinated substances (PFASs), in a variety of SRMs. Here we report levels determined in an interlaboratory comparison of up to 23 PFASs determined in five SRMs: sediment (SRMs 1941b and 1944), house dust (SRM 2585), soil (SRM 2586), and sludge (SRM 2781). Measurements presented show an array of PFASs, with perfluorooctane sulfonate being the most frequently detected. SRMs 1941b, 1944, and 2586 had relatively low concentrations of most PFASs measured while 23 PFASs were at detectable levels in SRM 2585 and most of the PFASs measured were at detectable levels in SRM 2781. The measurements made in this study were used to add values to the Certificates of Analysis for SRMs 2585 and 2781. Journal article published in Analytical and Bioanalytical Chemistry

Characterization of NIST food-matrix Standard Reference Materials for their vitamin C content.

PubMed

Thomas, Jeanice B; Yen, James H; Sharpless, Katherine E

2013-05-01

The vitamin C concentrations in three food-matrix Standard Reference Materials (SRMs) from the National Institute of Standards and Technology (NIST) have been determined by liquid chromatography (LC) with absorbance detection. These materials (SRM 1549a Whole Milk Powder, SRM 1849a Infant/Adult Nutritional Formula, and SRM 3233 Fortified Breakfast Cereal) have been characterized to support analytical measurements made by food processors that are required to provide information about their products' vitamin C content on the labels of products distributed in the United States. The SRMs are primarily intended for use in validating analytical methods for the determination of selected vitamins, elements, fatty acids, and other nutrients in these materials and in similar matrixes. They can also be used for quality assurance in the characterization of test samples or in-house control materials, and for establishing measurement traceability. Within-day precision of the LC method used to measure vitamin C in the food-matrix SRMs characterized in this study ranged from 2.7% to 6.5%.

NBS/EPA (NATIONAL BUREAU OF STANDARDS/ENVIRONMENTAL PROTECTION AGENCY) CERTIFIED REFERENCE MATERIAL PERFORMANCE AUDIT PROGRAM: STATUS REPORT 2

EPA Science Inventory

A traceability procedure has been established which allows specialty gas producers to prepare gaseous pollutant Certified Reference Materials (CRM's). The accuracy, stability and homogeneity of the CRM's approach those of NBS Standard Reference Materials (SRM's). As of October 19...

Commutability of NIST SRM 1955 Homocysteine and Folate in Frozen Human Serum with selected total homocysteine immunoassays and enzymatic assays.

PubMed

Nelson, Bryant C; Pfeiffer, Christine M; Zhang, Ming; Duewer, David L; Sharpless, Katherine E; Lippa, Katrice A

2008-09-01

The National Institute of Standards and Technology (NIST) has recently developed Standard Reference Material (SRM) 1955 Homocysteine and Folate in Frozen Human Serum with certified values for total homocysteine (tHcy) and 5-methyl-tetrahydrofolic acid. NIST has performed an international, interlaboratory assessment of SRM 1955 commutability; results are reported for tHcy only. Total Hcy was measured in 20 patient sera and in 3 levels of SRM 1955 using 14 immunoassays and/or enzymatic assays. Liquid chromatography/tandem mass spectrometry was utilized as the reference assay. An "errors-in-variables" statistical model was utilized to assess the commutability of SRM 1955. Normalized residuals ranged from -2.65 to 2.19 for SRM 1955. The median interlaboratory/interassay imprecision (CV) was approximately 4% for patient specimens and ranged from approximately 3% to approximately 7% for SRM 1955. The median intra-assay imprecision ranged from approximately 1% to approximately 13%. Orthogonal residuals, as a descriptor of assay accuracy, ranged from 0.29 to 7.71 and from 0.20 to 2.22 for patient specimens and SRM 1955 samples, respectively. The current study suggests that SRM 1955 is commutable with the investigated tHcy assays; however, a broader specimen set needs to be evaluated to completely substantiate this conclusion.

Characterization of Three Berry Standard Reference Materials for Nutrients

PubMed Central

Wood, Laura J.; Sharpless, Katherine E.; Pichon, Monique; Porter, Barbara J.; Yen, James H.; Ehling, Stefan

2011-01-01

The National Institute of Standards and Technology (NIST) has been working with the National Institutes of Health Office of Dietary Supplements to produce Standard Reference Materials (SRMs) of interest to analysts of dietary supplements. Some of these SRMs are traditional foods including SRM 3281 Cranberry (Fruit), SRM 3282 Low-Calorie Cranberry Juice Cocktail, and SRM 3287 Blueberry (Fruit), which have been characterized for nine nutritional elements and sugars. The blueberries have also been characterized for proximates, two water-soluble vitamins, and amino acids. These new materials are intended for use in method development and validation as well as for quality assurance and traceability when assigning values to in-house control materials. Foods can be difficult to analyze because of matrix effects. With the addition of these three new SRMs, it is now possible to more closely match controls to matrices and analyte levels for fruit and vegetable test samples. Several nutritional elements in these three SRMs are present at lower levels than those in other food-matrix SRMs. PMID:21688777

Synthetic musk fragrances in environmental Standard Reference Materials.

PubMed

Peck, Aaron M; Kucklick, John R; Schantz, Michele M

2007-04-01

Synthetic musk fragrances have been measured in water, air, sediments, sewage sludge, and biota worldwide. As the study of the environmental fate and impacts of these compounds progresses, the need for Standard Reference Materials (SRMs) for these compounds to facilitate analytical method improvement and interlaboratory comparisons becomes increasingly important. The National Institute of Standards and Technology (NIST) issues environmental matrix SRMs with certified concentrations for a variety of persistent organic pollutants including polycyclic aromatic hydrocarbons (PAHs), chlorinated pesticides, and polychlorinated biphenyl congeners (PCBs). Until now synthetic musk fragrance concentrations have not been reported in NIST SRMs. The objective of this study was to provide reference values for several commonly detected synthetic musk fragrances in several NIST natural matrix SRMs. In this study five polycyclic musk fragrances [HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-gamma-2-benzopyran), AHTN (7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene), ADBI (4-acetyl-1,1-dimethyl-6-tert-butylindane), AHMI (6-acetyl-1,1,2,3,3,5-hexamethylindane), and ATII (5-acetyl-1,1,2,6-tetramethyl-3-isopropylindane] and two nitro musk fragrances [musk xylene (1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene) and musk ketone (4-tert-butyl-3,5-dinitro-2,6-dimethylacetophenone)] were measured in selected environmental SRMs. Gas chromatography-electron impact mass spectrometry (GC/EI-MS) was used for all analyses. HHCB was the most frequently detected synthetic musk fragrance and was detected in SRM 2585 Organic Contaminants in House Dust, SRM 2781 Domestic Sludge, SRM 1974b Organics in Mussel Tissue (Mytilus edulis), and SRM 1947 Lake Michigan Fish Tissue. It was not detected in SRM 1946 Lake Superior Fish Tissue or SRM 1945 Organics in Whale Blubber. Concentrations of HHCB in these SRMs ranged from 1.12 ng/g in SRM 1947 to 92,901 ng/g in SRM 2781. All of the polycyclic musk fragrances were detected in SRM 2781 and all of the target compounds were detected in SRM 2585.

Improved efficiency of extraction of polycyclic aromatic hydrocarbons (PAHs) from the National Institute of Standards and Technology (NIST) Standard Reference Material Diesel Particulate Matter (SRM 2975) using accelerated solvent extraction.

PubMed

Masala, Silvia; Ahmed, Trifa; Bergvall, Christoffer; Westerholm, Roger

2011-12-01

The efficiency of extraction of polycyclic aromatic hydrocarbons (PAHs) with molecular masses of 252, 276, 278, 300, and 302 Da from standard reference material diesel particulate matter (SRM 2975) has been investigated using accelerated solvent extraction (ASE) with dichloromethane, toluene, methanol, and mixtures of toluene and methanol. Extraction of SRM 2975 using toluene/methanol (9:1, v/v) at maximum instrumental settings (200 °C, 20.7 MPa, and five extraction cycles) with 30-min extraction times resulted in the following elevations of the measured concentration when compared with the certified and reference concentrations reported by the National Institute of Standards and Technology (NIST): benzo[b]fluoranthene, 46%; benzo[k]fluoranthene, 137%; benzo[e]pyrene, 103%; benzo[a]pyrene, 1,570%; perylene, 37%; indeno[1,2,3-cd]pyrene, 41%; benzo[ghi]perylene, 163%; and coronene, 361%. The concentrations of the following PAHs were comparable to the reference values assigned by NIST: indeno[1,2,3-cd]fluoranthene, dibenz[a,h]anthracene, and picene. The measured concentration of dibenzo[a,e]-pyrene was lower than the information value reported by the NIST. The measured concentrations of other highly carcinogenic PAHs (dibenzo[a,l]pyrene, dibenzo[a,i]pyrene, and dibenzo[a,h]pyrene) in SRM 2975 are also reported. Comparison of measurements using the optimized ASE method and using similar conditions to those applied by the NIST for the assignment of PAH concentrations in SRM 2975 indicated that the higher values obtained in the present study were associated with more complete extraction of PAHs from the diesel particulate material. Re-extraction of the particulate samples demonstrated that the deuterated internal standards were more readily recovered than the native PAHs, which may explain the lower values reported by the NIST. The analytical results obtained in the study demonstrated that the efficient extraction of PAHs from SRM 2975 is a critical requirement for the accurate determination of PAHs with high molecular masses in this standard reference material and that the optimization of extraction conditions is essential to avoid underestimation of the PAH concentrations. The requirement is especially relevant to the human carcinogen benzo[a]pyrene, which is commonly used as an indicator of the carcinogenic risk presented by PAH mixtures.

Determination of polychlorinated dibenzo-p-dioxin and dibenzofuran congeners in air particulate and marine sediment standard reference materials (SRMs).

PubMed

Chiu, C H; Turle, R; Poole, G; Thibert, B; Brubaker, W W; Schantz, M M; Wise, S A

2001-02-01

Due to the limited number of environmental matrix certified reference materials (CRMs) with assigned values for natural levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), an interlaboratory study was undertaken by the National Institute of Standards and Technology (NIST) and Environment Canada to establish reference concentration values for selected PCDD/Fs in two well-characterized NIST Standard Reference Materials (SRMs): SRM 1649a (Urban Dust) and SRM 1944 (New York/New Jersey Waterway Sediment). Results from 14 laboratories were used to provide reference values for the seventeen 2, 3, 7, 8-substituted PCDD/F congeners, the totals for individual tetra- through hepta-substituted PCDD/F homologues, and the total amount of tetra- through hepta-substituted PCDD/Fs. The mass fractions for the individual 2, 3, 7, 8-substituted congeners range from approximately 0.01 microg/kg to 7 microg/kg dry mass.

On-line double isotope dilution laser ablation inductively coupled plasma mass spectrometry for the quantitative analysis of solid materials.

PubMed

Fernández, Beatriz; Rodríguez-González, Pablo; García Alonso, J Ignacio; Malherbe, Julien; García-Fonseca, Sergio; Pereiro, Rosario; Sanz-Medel, Alfredo

2014-12-03

We report on the determination of trace elements in solid samples by the combination of on-line double isotope dilution and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The proposed method requires the sequential analysis of the sample and a certified natural abundance standard by on-line IDMS using the same isotopically-enriched spike solution. In this way, the mass fraction of the analyte in the sample can be directly referred to the certified standard so the previous characterization of the spike solution is not required. To validate the procedure, Sr, Rb and Pb were determined in certified reference materials with different matrices, including silicate glasses (SRM 610, 612 and 614) and powdered samples (PACS-2, SRM 2710a, SRM 1944, SRM 2702 and SRM 2780). The analysis of powdered samples was carried out both by the preparation of pressed pellets and by lithium borate fusion. Experimental results for the analysis of powdered samples were in agreement with the certified values for all materials. Relative standard deviations in the range of 6-21% for pressed pellets and 3-21% for fused solids were obtained from n=3 independent measurements. Minimal sample preparation, data treatment and consumption of the isotopically-enriched isotopes are the main advantages of the method over previously reported approaches. Copyright © 2014 Elsevier B.V. All rights reserved.

Certification of NIST standard reference material 2389a, amino acids in 0.1 mol/L HCl--quantification by ID LC-MS/MS.

PubMed

Lowenthal, Mark S; Yen, James; Bunk, David M; Phinney, Karen W

2010-05-01

An isotope-dilution liquid chromatography-tandem mass spectrometry (ID LC-MS/MS) measurement procedure was developed to accurately quantify amino acid concentrations in National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 2389a-amino acids in 0.1 mol/L hydrochloric acid. Seventeen amino acids were quantified using selected reaction monitoring on a triple quadrupole mass spectrometer. LC-MS/MS results were compared to gravimetric measurements from the preparation of SRM 2389a-a reference material developed at NIST and intended for use in intra-laboratory calibrations and quality control. Quantitative mass spectrometry results and gravimetric values were statistically combined into NIST-certified mass fraction values with associated uncertainty estimates. Coefficients of variation (CV) for the repeatability of the LC-MS/MS measurements among amino acids ranged from 0.33% to 2.7% with an average CV of 1.2%. Average relative expanded uncertainty of the certified values including Types A and B uncertainties was 3.5%. Mean accuracy of the LC-MS/MS measurements with gravimetric preparation values agreed to within |1.1|% for all amino acids. NIST SRM 2389a will be available for characterization of routine methods for amino acid analysis and serves as a standard for higher-order measurement traceability. This is the first time an ID LC-MS/MS methodology has been applied for quantifying amino acids in a NIST SRM material.

Certification of elements in and use of standard reference material 3280 multivitamin/multielement tablets

USDA-ARS?s Scientific Manuscript database

Standard Reference Material (SRM) 3280 Multivitamin/Multielement Tablets was issued by the National Institute of Standards and Technology (NIST) in 2009 and has certified and reference mass fraction values for 13 vitamins, 26 elements, and 2 carotenoids. Elements were measured using two or more ana...

ORGANIC CHARACTERIZATION OF AIRBORNE PARTICLES: INTERLABORATORY COMPARISON STUDIES AND THE DEVELOPMENT OF STANDARDS AND REFERENCE MATERIALS

EPA Science Inventory

Investigators characterizing and quantifying the organic compounds in particulate matter (PM) have completed the second interlaboratory comparison study. The first study used a subset of SRM1649a sieved to <63um(API) as an unknown sample, an extract of API, and SRM1649a for u...

Concurrent determination of 237Np and Pu isotopes using ICP-MS: analysis of NIST environmental matrix standard reference materials 4357, 1646a, and 2702.

PubMed

Matteson, Brent S; Hanson, Susan K; Miller, Jeffrey L; Oldham, Warren J

2015-04-01

An optimized method was developed to analyze environmental soil and sediment samples for (237)Np, (239)Pu, and (240)Pu by ICP-MS using a (242)Pu isotope dilution standard. The high yield, short time frame required for analysis, and the commercial availability of the (242)Pu tracer are significant advantages of the method. Control experiments designed to assess method uncertainty, including variation in inter-element fractionation that occurs during the purification protocol, suggest that the overall precision for measurements of (237)Np is typically on the order of ± 5%. Measurements of the (237)Np concentration in a Peruvian Soil blank (NIST SRM 4355) spiked with a known concentration of (237)Np tracer confirmed the accuracy of the method, agreeing well with the expected value. The method has been used to determine neptunium and plutonium concentrations in several environmental matrix standard reference materials available from NIST: SRM 4357 (Radioactivity Standard), SRM 1646a (Estuarine Sediment) and SRM 2702 (Inorganics in Marine Sediment). Copyright © 2015 Elsevier Ltd. All rights reserved.

Determination of polycyclic aromatic hydrocarbons with molecular weight 300 and 302 in environmental-matrix standard reference materials by gas chromatography/mass spectrometry.

PubMed

Schubert, Patricia; Schantz, Michele M; Sander, Lane C; Wise, Stephen A

2003-01-15

An analytical approach based on gas chromatography/ mass spectrometry (GC/MS) is presented for the measurement of polycyclic aromatic hydrocarbons with molecular weight (MW) 300 and 302 in environmental samples. Three different GC stationary phases [5% and 50% phenyl methylpolysiloxane and dimethyl (50% liquid crystalline) polysiloxane] were compared, and retention indexes (RI) are given for 23 individual MW 302 isomers. Identification of MW 300 and 302 isomers in four environmental-matrix Standard Reference Materials (SRMs) (SRM 1597, coal tar extract; SRM 1648 and SRM 1649a, air particulate matter; and SRM 1941, marine sediment) was based on the comparison of RI data and mass spectra from authentic standards. Dibenzo[a,l]pyrene, which is of considerable interest because of its high carcinogenicity, was identified and quantified in the four environmental-matrix SRMs. A total of 23 isomers of MW 302 and four isomers of MW 300 were quantified in four different environmental-matrix SRMs, and the results are compared to previously reported results based on liquid chromatography with fluorescence detection.

Determination of perfluorinated alkyl acid concentrations in human serum and milk standard reference materials.

PubMed

Keller, Jennifer M; Calafat, Antonia M; Kato, Kayoko; Ellefson, Mark E; Reagen, William K; Strynar, Mark; O'Connell, Steven; Butt, Craig M; Mabury, Scott A; Small, Jeff; Muir, Derek C G; Leigh, Stefan D; Schantz, Michele M

2010-05-01

Standard Reference Materials (SRMs) are certified reference materials produced by the National Institute of Standards and Technology that are homogeneous materials well characterized with values for specified properties, such as environmental contaminant concentrations. They can be used to validate measurement methods and are critical in improving data quality. Disagreements in perfluorinated alkyl acid (PFAA) concentrations measured in environmental matrices during past interlaboratory comparisons emphasized the need for SRMs with values assigned for PFAAs. We performed a new interlaboratory comparison among six laboratories and provided, for the first time, value assignment of PFAAs in SRMs. Concentrations for perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and other PFAAs in two human serum and two human milk SRMs are reported. PFAA concentration measurements agreed for serum SRM 1957 using different analytical methods in six laboratories and for milk SRM 1954 in three laboratories. The interlaboratory relative standard deviation for PFOS in SRM 1957 was 7%, which is an improvement over past interlaboratory studies. Matrix interferences are discussed, as well as temporal trends and the percentage of branched vs. linear isomers. The concentrations in these SRMs are similar to the present-day average concentrations measured in human serum and milk, resulting in representative and useful control materials for PFAA human monitoring studies.

The determination of water in crude oil and transformer oil reference materials.

PubMed

Margolis, Sam A; Hagwood, Charles

2003-05-01

The measurement of the amount of water in oils is of significant economic importance to the industrial community, particularly to the electric power and crude oil industries. The amount of water in transformer oils is critical to their normal function and the amount of water in crude oils affects the cost of the crude oil at the well head, the pipeline, and the refinery. Water in oil Certified Reference Materials (CRM) are essential for the accurate calibration of instruments that are used by these industries. Three NIST Standard Reference Materials (SRMs) have been prepared for this purpose. The water in these oils has been measured by both coulometric and volumetric Karl Fischer methods. The compounds (such as sulfur compounds) that interfere with the Karl Fischer reaction (interfering substances) and inflate the values for water by also reacting with iodine have been measured coulometrically. The measured water content of Reference Material (RM) 8506a Transformer Oil is 12.1+/-1.9 mg kg(-1) (plus an additional 6.2+/-0.9 mg kg(-1) of interfering substances). The measured water content of SRM 2722 Sweet Crude Oil, is 99+/-6 mg kg(-1) (plus an additional 5+/-2 mg kg(-1) of interfering substances). The measured water content of SRM 2721 Sour Crude Oil, is 134+/-18 mg kg(-1) plus an additional 807+/-43 mg kg(-1) of interfering substances. Interlaboratory studies conducted with these oil samples (using SRM 2890, water saturated 1-octanol, as a calibrant) are reported. Some of the possible sources of bias in these measurements were identified, These include: improperly calibrated instruments, inability to measure the calibrant accurately, Karl Fischer reagent selection, and volatilization of the interfering substances in SRM 2721.

Development of a 100 nmol mol(-1) propane-in-air SRM for automobile-exhaust testing for new low-emission requirements.

PubMed

Rhoderick, George C

2007-04-01

New US federal low-level automobile emission requirements, for example zero-level-emission vehicle (ZLEV), for hydrocarbons and other species, have resulted in the need by manufacturers for new certified reference materials. The new emission requirement for hydrocarbons requires the use, by automobile manufacturing testing facilities, of a 100 nmol mol(-1) propane in air gas standard. Emission-measurement instruments are required, by federal law, to be calibrated with National Institute of Standards and Technology (NIST) traceable reference materials. Because a NIST standard reference material (SRM) containing 100 nmol mol(-1) propane was not available, the US Environmental Protection Agency (EPA) and the Automobile Industry/Government Emissions Research Consortium (AIGER) requested that NIST develop such an SRM. A cylinder lot of 30 gas mixtures containing 100 nmol mol(-1) propane in air was prepared in 6-L aluminium gas cylinders by a specialty gas company and delivered to the Gas Metrology Group at NIST. Another mixture, contained in a 30-L aluminium cylinder and included in the lot, was used as a lot standard (LS). Using gas chromatography with flame-ionization detection all 30 samples were compared to the LS to obtain the average of six peak-area ratios to the LS for each sample with standard deviations of <0.31%. The average sample-to-LS ratio determinations resulted in a range of 0.9828 to 0.9888, a spread of 0.0060, which corresponds to a relative standard deviation of 0.15% of the average for all 30 samples. NIST developed its first set of five propane in air primary gravimetric standards covering a concentration range 91 to 103 nmol mol(-1) with relative uncertainties of 0.15%. This new suite of propane gravimetric standards was used to analyze and assign a concentration value to the SRM LS. On the basis of these data each SRM sample was individually certified, furnishing the desired relative expanded uncertainty of +/-0.5%. Because automobile companies use total hydrocarbons to make their measurements, it was also vital to assign a methane concentration to the SRM samples. Some of the SRM samples were analyzed and found to contain 1.2 nmol mol(-1) methane. Twenty-five of the samples were certified and released as SRM 2765.

Extract-filter-shoot liquid chromatography/mass spectrometry for analysis of vitamin D2 in a powdered supplement capsule and SRM 3280

USDA-ARS?s Scientific Manuscript database

An ‘extract-filter-shoot’ method for analysis of vitamin D2, ergocalciferol, in a dry powdered dietary supplement capsule containing rice flour excipient and in National Institute of Standards and Technology (NIST) standard reference material (SRM) 3280 is reported. Quantification of vitamin D2 was...

Pressurized liquid extraction of diesel and air particulate standard reference materials: effect of extraction temperature and pressure.

PubMed

Schantz, Michele M; McGaw, Elizabeth; Wise, Stephen A

2012-10-02

Four particulate matter Standard Reference Materials (SRMs) available from the National Institute of Standards and Technology (NIST) were used to evaluate the effect of solvent, number of static cycles and static times, pressure, and temperature when using pressurized liquid extraction (PLE) for the extraction of polycyclic aromatic hydrocarbons (PAHs) and nitrated-PAHs. The four materials used in the study were SRM 1648a Urban Particulate Matter, SRM 1649b Urban Dust, SRM 1650b Diesel Particulate Matter, and SRM 2975 Diesel Particulate Matter (Industrial Forklift). The results from the study indicate that the choice of solvent, dichloromethane compared to toluene and toluene/methanol mixtures, had little effect on the extraction efficiency. With three to five extraction cycles, increasing the extraction time for each cycle from 5 to 30 min had no significant effect on the extraction efficiency. The differences in extraction efficiency were not significant (with over 95% of the differences being <10%) when the pressure was increased from 13.8 to 20.7 MPa. The largest increase in extraction efficiency occurred for selected PAHs when the temperature of extraction was increased from 100 to 200 °C. At 200 °C naphthalene, biphenyl, fluorene, dibenzothiophene, and anthracene show substantially higher mass fractions (>30%) than when extracted at 100 °C in all the SRMs studied. For SRM 2975, large increases (>100%) are also observed for some other PAHs including benz[a]anthracene, benzo[k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, benzo[ghi]perylene, and benzo[b]chrysene when extracted at the higher temperatures; however, similar trends were not observed for the other diesel particulate sample, SRM 1650b. The results are discussed in relation to the use of the SRMs for evaluating analytical methods.

Quantification of Complex Polycyclic Aromatic Hydrocarbon Mixtures in Standard Reference Materials Using GC×GC/ToF-MS

PubMed Central

Manzano, Carlos; Hoh, Eunha; Massey Simonich, Staci L.

2014-01-01

This research is the first to quantify complex PAH mixtures in NIST SRMs using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/ToF-MS), with and without extract cleanup, and reports previously unidentified PAH isomers in the NIST SRMs. We tested a novel, high orthogonality GC column combination (LC-50×NSP-35), as well as with a commonly used column combination (Rtx-5ms×Rxi-17) for the quantification of a complex mixture of 85 different PAHs, including parent (PAHs), alkyl- (MPAHs), nitro- (NPAHs), oxy- (OPAHs), thio- (SPAHs), bromo- (BrPAHs), and chloro-PAHs (ClPAHs) in extracts from two standard reference materials: NIST SRM1650b (diesel particulate matter), with cleanup and NIST SRM1975 (diesel particulate extract), with and without extract cleanup. The LC-50×NSP-35 column combination resulted in an average absolute percent difference of 33.8%, 62.2% and 30.8% compared to the NIST certified PAH concentrations for NIST SRM1650b, NIST SRM1975 with cleanup and NIST SRM1975 without cleanup, while the Rtx-5ms×Rxi-17 resulted in an absolute percent difference of 38.6%, 67.2% and 79.6% for NIST SRM1650b, NIST SRM1975 with cleanup and NIST SRM1975 without cleanup, respectively. This GC×GC/ToF-MS method increases the number of PAHs detected and quantified in complex environmental extracts using a single chromatographic run. Without clean-up, 7 additional compounds were detected and quantified in NIST SRM1975 using the LC-50×NSP-35 column combination. These results suggest that the use of the LC-50×NSP-35 column combination in GC×GC/ToF-MS not only results in better chromatographic resolution and greater orthogonality for the separation of complex PAH mixtures, but can also be used for the accurate quantification of complex PAH mixtures in environmental extracts without cleanup. PMID:23932031

Polychlorinated biphenyls (PCB), chlorinated pesticides, and polycyclic aromatic hydrocarbons (PAHs) in environmental standard reference materials

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

Poster, D.L.; Schantz, M.M.; Parris, R.M.

1995-12-31

Standard reference materials (SRMs) are certified reference materials issued by the National Institute of Standards and Technology (NIST). Natural matrix environmental sample SRMs have been developed the Analytical Chemistry Division to assist in validating measurements for organic contaminants in the environment. Many of these are well characterized for contaminants such as polychlorinated biphenyls (PCBs), chlorinated pesticides, and polycyclic aromatic hydrocarbons (PAHs). SRM 1649, Organics in Urban Dust, is currently available with certified concentrations for 5 PAHs but because of the widespread use of this material in air pollution monitoring programs and to expand the usefulness of this material, the authorsmore » are further characterizing the material for a larger number of PAHs as well as PCBs and chlorinated pesticides. They will also soon issue a diesel particulate extract (SRM 1975) that is well characterized for PAHS, including many nitrogen substituted compounds. In addition to natural matrix materials, solutions useful for calibrating chromatographic detector response factors and retention times, and spiking sample blanks for determination of analyte recoveries, are also available. Solution SRMs currently available contain PCS congeners, chlorinated pesticides, and PAHs. New solution SRMs in preparation will contain additional chlorinated pesticides, PCB congeners (e.g., non-ortho substituted chlorobiphenyls), and perdeuterated PAHs. Recent SRM work will be presented with particular attention on the methods used for determining organic contaminant concentrations in the urban dust material and in the diesel particulate extract.« less

REFERENCE MATERIALS AND QUALITY ASSURANCE FOR THE CHARACTERIZATION OF ORGANIC COMPOUNDS IN PARTICULATE MATTER

EPA Science Inventory

One of the first environmental matrix Standard Reference Materials (SRMs) developed by the National Institute of Standards and Technology (NIST) for determination of organic species was SRM 1649 Urban Dust, ambient total suspended particulate matter (PM) collected in Washington D...

Harmonizing lipidomics: NIST interlaboratory comparison exercise for lipidomics using SRM 1950-Metabolites in Frozen Human Plasma.

PubMed

Bowden, John A; Heckert, Alan; Ulmer, Candice Z; Jones, Christina M; Koelmel, Jeremy P; Abdullah, Laila; Ahonen, Linda; Alnouti, Yazen; Armando, Aaron M; Asara, John M; Bamba, Takeshi; Barr, John R; Bergquist, Jonas; Borchers, Christoph H; Brandsma, Joost; Breitkopf, Susanne B; Cajka, Tomas; Cazenave-Gassiot, Amaury; Checa, Antonio; Cinel, Michelle A; Colas, Romain A; Cremers, Serge; Dennis, Edward A; Evans, James E; Fauland, Alexander; Fiehn, Oliver; Gardner, Michael S; Garrett, Timothy J; Gotlinger, Katherine H; Han, Jun; Huang, Yingying; Neo, Aveline Huipeng; Hyötyläinen, Tuulia; Izumi, Yoshihiro; Jiang, Hongfeng; Jiang, Houli; Jiang, Jiang; Kachman, Maureen; Kiyonami, Reiko; Klavins, Kristaps; Klose, Christian; Köfeler, Harald C; Kolmert, Johan; Koal, Therese; Koster, Grielof; Kuklenyik, Zsuzsanna; Kurland, Irwin J; Leadley, Michael; Lin, Karen; Maddipati, Krishna Rao; McDougall, Danielle; Meikle, Peter J; Mellett, Natalie A; Monnin, Cian; Moseley, M Arthur; Nandakumar, Renu; Oresic, Matej; Patterson, Rainey; Peake, David; Pierce, Jason S; Post, Martin; Postle, Anthony D; Pugh, Rebecca; Qiu, Yunping; Quehenberger, Oswald; Ramrup, Parsram; Rees, Jon; Rembiesa, Barbara; Reynaud, Denis; Roth, Mary R; Sales, Susanne; Schuhmann, Kai; Schwartzman, Michal Laniado; Serhan, Charles N; Shevchenko, Andrej; Somerville, Stephen E; St John-Williams, Lisa; Surma, Michal A; Takeda, Hiroaki; Thakare, Rhishikesh; Thompson, J Will; Torta, Federico; Triebl, Alexander; Trötzmüller, Martin; Ubhayasekera, S J Kumari; Vuckovic, Dajana; Weir, Jacquelyn M; Welti, Ruth; Wenk, Markus R; Wheelock, Craig E; Yao, Libin; Yuan, Min; Zhao, Xueqing Heather; Zhou, Senlin

2017-12-01

As the lipidomics field continues to advance, self-evaluation within the community is critical. Here, we performed an interlaboratory comparison exercise for lipidomics using Standard Reference Material (SRM) 1950-Metabolites in Frozen Human Plasma, a commercially available reference material. The interlaboratory study comprised 31 diverse laboratories, with each laboratory using a different lipidomics workflow. A total of 1,527 unique lipids were measured across all laboratories and consensus location estimates and associated uncertainties were determined for 339 of these lipids measured at the sum composition level by five or more participating laboratories. These evaluated lipids detected in SRM 1950 serve as community-wide benchmarks for intra- and interlaboratory quality control and method validation. These analyses were performed using nonstandardized laboratory-independent workflows. The consensus locations were also compared with a previous examination of SRM 1950 by the LIPID MAPS consortium. While the central theme of the interlaboratory study was to provide values to help harmonize lipids, lipid mediators, and precursor measurements across the community, it was also initiated to stimulate a discussion regarding areas in need of improvement. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

Ultra-low level plutonium isotopes in the NIST SRM 4355A (Peruvian Soil-1).

PubMed

Inn, Kenneth G W; LaRosa, Jerome; Nour, Svetlana; Brooks, George; LaMont, Steve; Steiner, Rob; Williams, Ross; Patton, Brad; Bostick, Debbie; Eiden, Gregory; Petersen, Steve; Douglas, Matthew; Beals, Donna; Cadieux, James; Hall, Greg; Goldberg, Steve; Vogt, Stephan

2009-05-01

For more than 20 years, countries and their agencies which monitor radionuclide discharge sites and storage facilities have relied on the National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 4355 Peruvian Soil. Its low fallout contamination makes it an ideal soil blank for measurements associated with terrestrial-pathway-to-man studies. Presently, SRM 4355 is out of stock, and a new batch of the Peruvian soil is currently under development as future NIST SRM 4355A. Both environmental radioanalytical laboratories and mass spectrometry communities will benefit from the use of this SRM. The former must assess their laboratory procedural contamination and measurement detection limits by measurement of blank sample material. The Peruvian Soil is so low in anthropogenic radionuclide content that it is a suitable virtual blank. On the other hand, mass spectrometric laboratories have high sensitivity instruments that are capable of quantitative isotopic measurements at low plutonium levels in the SRM 4355 (first Peruvian Soil SRM) that provided the mass spectrometric community with the calibration, quality control, and testing material needed for methods development and legal defensibility. The quantification of the ultra-low plutonium content in the SRM 4355A was a considerable challenge for the mass spectrometric laboratories. Careful blank control and correction, isobaric interferences, instrument stability, peak assessment, and detection assessment were necessary. Furthermore, a systematic statistical evaluation of the measurement results and considerable discussions with the mass spectroscopy metrologists were needed to derive the certified values and uncertainties. The one sided upper limit of the 95% tolerance with 95% confidence for the massic (239)Pu content in SRM 4355A is estimated to be 54,000 atoms/g.

Comparative physicochemical and biological characterization of NIST Interim Reference Material PM2.5 and SRM 1648 in human A549 and mouse RAW264.7 cells.

PubMed

Mitkus, Robert J; Powell, Jan L; Zeisler, Rolf; Squibb, Katherine S

2013-12-01

The epidemiological association between exposure to fine particulate matter (PM2.5) and adverse health effects is well-known. Here we report the size distribution, metals content, endotoxin content, and biological activity of National Institute of Standards and Technology (NIST) Interim Reference Material (RM) PM2.5. Biological activity was measured in vitro by effects on cell viability and the release of four inflammatory immune mediators, from human A549 alveolar epithelial cells or murine RAW264.7 monocytes. A dose range covering three orders of magnitude (1-1000μg/mL) was tested, and biological activity was compared to an existing Standard Reference Material (SRM) for urban PM (NIST SRM 1648). Robust release of IL-8 and MCP-1 from A549 cells was observed in response to IRM PM2.5 exposures. Significant TNF-α, but not IL-6, secretion from RAW264.7 cells was observed in response to both IRM PM2.5 and SRM 1648 particle types. Cytokine or chemokine release at high doses often occurred in the presence of cytotoxicity, likely as a result of externalization of preformed mediator. Our results are consistent with a local cytotoxic and pro-inflammatory mechanism of response to exposure to inhaled ambient PM2.5 and reinforce the continued relevance of in vitro assays for mechanistic research in PM toxicology. Our study furthers the goal of developing reference samples of environmentally relevant particulate matter of various sizes that can be used for hypothesis testing by multiple investigators. Published by Elsevier Ltd.

Recognizing and overcoming analytical error in the use of ICP-MS for the determination of cadmium in breakfast cereal and dietary supplements.

PubMed

Murphy, Karen E; Vetter, Thomas W

2013-05-01

The potential effect of spectral interference on the accurate measurement of the cadmium (Cd) mass fraction in fortified breakfast cereal and a variety of dietary supplement materials using inductively coupled plasma quadrupole mass spectrometry was studied. The materials were two new standard reference materials (SRMs)--SRM 3233 Fortified Breakfast Cereal and SRM 3532 Calcium Dietary Supplement--as well as several existing materials--SRM 3258 Bitter Orange Fruit, SRM 3259 Bitter Orange Extract, SRM 3260 Bitter Orange-containing Solid Oral Dosage Form, and SRM 3280 Multivitamin/Multielement Tablets. Samples were prepared for analysis using the method of isotope dilution and measured using various operating and sample introduction configurations including standard mode, collision cell with kinetic energy discrimination mode, and standard mode with sample introduction via a desolvating nebulizer system. Three isotope pairs, (112)Cd/(111)Cd, (113)Cd/(111)Cd, and (114)Cd/(111)Cd, were measured. Cadmium mass fraction results for the unseparated samples of each material, measured using the three instrument configurations and isotope pairs, were compared to the results obtained after the matrix was removed via chemical separation using anion exchange chromatography. In four of the six materials studied, measurements using the standard mode with sample introduction via the desolvating nebulizer gave results for the unseparated samples quantified with the (112)Cd/(111)Cd isotope pair that showed a positive bias relative to the matrix-separated samples, which indicated a persistent inference at m/z112 with this configuration. Use of the standard mode, without the desolvating nebulizer, also gave results that showed a positive bias for the unseparated samples quantified with the (112)Cd/(111)Cd isotope pair in three of the materials studied. Collision cell/kinetic energy discrimination mode, however, was very effective for reducing spectral interference for Cd in all of the materials and isotope pairs studied, except in the multivitamin/multielement matrix (SRM 3280) where the large corrections for known isobaric interferences or unidentified interferences compromised the accuracy. For SRM 3280, matrix separation provided the best method to achieve accurate measurement of Cd.

Longitudinal meta-analysis of NIST pH Standard Reference Materials(®): a complement to pH key comparisons.

PubMed

Pratt, Kenneth W

2015-04-01

This meta-analysis assesses the long-term (up to 70 years) within-laboratory variation of the NIST pH Standard Reference Material® (SRM) tetroxalate, phthalate, phosphate, borate, and carbonate buffers. Values of ΔpH(S), the difference between the certified pH value, pH(S), of each SRM issue and the mean of all pH(S) values for the given SRM at that Celsius temperature, t, are graphed as a function of the SRM issue and t. In most cases, |ΔpH(S)| < 0.004. Deviations from the nominal base:acid amount (mole) ratio of a buffer yield t-independent, constant shifts in ΔpH(S). The mean ΔpH(S) characterizes such deviations. The corresponding mole fraction of impurity in the conjugate buffer component is generally <0.3 %. Changes in the equipment, personnel, materials, and methodology of the pH(S) measurement yield t-dependent variations. The standard deviation of ΔpH(S) characterizes such changes. Standard deviations of ΔpH(S) are generally 0.0015 or less. The results provide a long-term, single-institution complement to the time-specific, multi-institution results of pH key comparisons administered by the Consultative Committee for Metrology in Chemistry and Biology (CCQM).

Addressing the amorphous content issue in quantitative phase analysis: the certification of NIST standard reference material 676a.

PubMed

Cline, James P; Von Dreele, Robert B; Winburn, Ryan; Stephens, Peter W; Filliben, James J

2011-07-01

A non-diffracting surface layer exists at any boundary of a crystal and can comprise a mass fraction of several percent in a finely divided solid. This has led to the long-standing issue of amorphous content in standards for quantitative phase analysis (QPA). NIST standard reference material (SRM) 676a is a corundum (α-Al(2)O(3)) powder, certified with respect to phase purity for use as an internal standard in powder diffraction QPA. The amorphous content of SRM 676a is determined by comparing diffraction data from mixtures with samples of silicon powders that were engineered to vary their specific surface area. Under the (supported) assumption that the thickness of an amorphous surface layer on Si was invariant, this provided a method to control the crystalline/amorphous ratio of the silicon components of 50/50 weight mixtures of SRM 676a with silicon. Powder diffraction experiments utilizing neutron time-of-flight and 25 keV and 67 keV X-ray energies quantified the crystalline phase fractions from a series of specimens. Results from Rietveld analyses, which included a model for extinction effects in the silicon, of these data were extrapolated to the limit of zero amorphous content of the Si powder. The certified phase purity of SRM 676a is 99.02% ± 1.11% (95% confidence interval). This novel certification method permits quantification of amorphous content for any sample of interest, by spiking with SRM 676a.

SRM 2460/2461 Standard Bullets and Casings Project

PubMed Central

Song, J.; Whitenton, E.; Kelley, D.; Clary, R.; Ma, L.; Ballou, S.; Ols, M.

2004-01-01

The National Institute of Standards and Technology Standard Reference Material (SRM) 2460/2461 standard bullets and casings project will provide support to firearms examiners and to the National Integrated Ballistics Information Network (NIBIN) in the United States. The SRM bullet is designed as both a virtual and a physical bullet profile signature standard. The virtual standard is a set of six digitized bullet profile signatures originally traced from six master bullets fired at the Bureau of Alcohol, Tobacco and Firearms (ATF) and the Federal Bureau of Investigation (FBI). By using the virtual signature standard to control the tool path on a numerically controlled diamond turning machine, 40 SRM bullets were produced. A profile signature measurement system was established for the SRM bullets. The profile signature differences are quantified by the maximum of the cross correlation function and by the signature difference between pairs of compared profile signatures measured on different SRM bullets. Initial measurement results showed high reproducibility for both the measurement system and production process of the SRM bullets. A traceability scheme has been proposed to establish the measurement traceability for nationwide bullet signature measurements to NIST, ATF and FBI. Prototype SRM casings have also been developed. PMID:27366632

Metabolite profiling of a NIST Standard Reference Material for human plasma (SRM 1950): GC-MS, LC-MS, NMR, and clinical laboratory analyses, libraries, and web-based resources.

PubMed

Simón-Manso, Yamil; Lowenthal, Mark S; Kilpatrick, Lisa E; Sampson, Maureen L; Telu, Kelly H; Rudnick, Paul A; Mallard, W Gary; Bearden, Daniel W; Schock, Tracey B; Tchekhovskoi, Dmitrii V; Blonder, Niksa; Yan, Xinjian; Liang, Yuxue; Zheng, Yufang; Wallace, William E; Neta, Pedatsur; Phinney, Karen W; Remaley, Alan T; Stein, Stephen E

2013-12-17

Recent progress in metabolomics and the development of increasingly sensitive analytical techniques have renewed interest in global profiling, i.e., semiquantitative monitoring of all chemical constituents of biological fluids. In this work, we have performed global profiling of NIST SRM 1950, "Metabolites in Human Plasma", using GC-MS, LC-MS, and NMR. Metabolome coverage, difficulties, and reproducibility of the experiments on each platform are discussed. A total of 353 metabolites have been identified in this material. GC-MS provides 65 unique identifications, and most of the identifications from NMR overlap with the LC-MS identifications, except for some small sugars that are not directly found by LC-MS. Also, repeatability and intermediate precision analyses show that the SRM 1950 profiling is reproducible enough to consider this material as a good choice to distinguish between analytical and biological variability. Clinical laboratory data shows that most results are within the reference ranges for each assay. In-house computational tools have been developed or modified for MS data processing and interactive web display. All data and programs are freely available online at http://peptide.nist.gov/ and http://srmd.nist.gov/ .

Field Demonstration and Validation of a New Device for Measuring Water and Solute Fluxes at CFB Borden

DTIC Science & Technology

2006-11-01

All Quality Control Reference Materials are acquired only from authorized vendors or sources commonly used by U.S. EPA Regional Laboratories...Institue of Standards and Testing (NITS) Standard Reference Materials (SRM) or to the U.S. EPA Reference Standards. Working Standards The commercial...contaminants from clothing or equipment by blowing, shaking or any other means that may disperse material into the air is prohibited. 7.1.3. All disposable

Evaluation of a standardized micro-vacuum sampling method for collection of surface dust.

PubMed

Ashley, Kevin; Applegate, Gregory T; Wise, Tamara J; Fernback, Joseph E; Goldcamp, Michael J

2007-03-01

A standardized procedure for collecting dust samples from surfaces using a micro-vacuum sampling technique was evaluated. Experiments were carried out to investigate the collection efficiency of the vacuum sampling method described in ASTM Standard D7144, "Standard Practice for Collection of Surface Dust by Micro-Vacuum Sampling for Subsequent Metals Determination." Weighed masses ( approximately 5, approximately 10 and approximately 25 mg) of three NIST Standard Reference Materials (SRMs) were spiked onto surfaces of various substrates. The SRMs used were: (1) Powdered Lead-Based Paint; (2) Urban Particulate Matter; and (3) Trace Elements in Indoor Dust. Twelve different substrate materials were chosen to be representative of surfaces commonly encountered in occupational and/or indoor settings: (1) wood, (2) tile, (3) linoleum, (4) vinyl, (5) industrial carpet, (6) plush carpet, (7,8) concrete block (painted and unpainted), (9) car seat material, (10) denim, (11) steel, and (12) glass. Samples of SRMs originally spiked onto these surfaces were collected using the standardized micro-vacuum sampling procedure. Gravimetric analysis of material collected within preweighed Accucapinserts (housed within the samplers) was used to measure SRM recoveries. Recoveries ranged from 21.6% (+/- 10.4%, 95% confidence limit [CL]) for SRM 1579 from industrial carpet to 59.2% (+/- 11.0%, 95% CL) for SRM 1579 from glass. For most SRM/substrate combinations, recoveries ranged from approximately 25% to approximately 50%; variabilities differed appreciably. In general, SRM recoveries were higher from smooth and hard surfaces and lower from rough and porous surfaces. Material captured within collection nozzles attached to the sampler inlets was also weighed. A significant fraction of SRM originally spiked onto substrate surfaces was captured within collection nozzles. Percentages of SRMs captured within collection nozzles ranged from approximately 13% (+/- 4 - +/- 5%, 95% CLs) for SRMs 1579 and 2583 from industrial carpet to approximately 45% (+/- 7 - +/- 26%, 95% CLs) for SRM 1648 from glass, tile and steel. For some substrates, loose material from the substrate itself (i.e., substrate particles and fibers) was sometimes collected along with the SRM, both within Accucaps as well as collection nozzles. Co-collection of substrate material can bias results and contribute to sampling variability. The results of this work have provided performance data on the standardized micro-vacuum sampling procedure.

Determination of non-certified levoglucosan, sugar polyols and ergosterol in NIST Standard Reference Material 1649a

NASA Astrophysics Data System (ADS)

Pomata, Donatella; Di Filippo, Patrizia; Riccardi, Carmela; Buiarelli, Francesca; Gallo, Valentina

2014-02-01

Organic component of airborne particulate matter originates from both natural and anthropogenic sources whose contributions can be identified through the analysis of chemical markers. The validation of analytical methods for analysis of compounds used as chemical markers is of great importance especially if they must be determined in rather complex matrices. Currently, standard reference materials (SRM) with certified values for all those analytes are not available. In this paper, we report a method for the simultaneous determination of levoglucosan and xylitol as tracers for biomass burning emissions, and arabitol, mannitol and ergosterol as biomarkers for airborne fungi in SRM 1649a, by GC/MS. Their quantitative analysis in SRM 1649a was carried out using both internal standard calibration curves and standard addition method. A matrix effect was observed for all analytes, minor for levoglucosan and major for polyols and ergosterol. The results related to levoglucosan around 160 μg g-1 agreed with those reported by other authors, while no comparison was possible for xylitol (120 μg g-1), arabitol (15 μg g-1), mannitol (18 μg g-1), and ergosterol (0.5 μg g-1). The analytical method used for SRM 1649a was also applied to PM10 samples collected in Rome during four seasonal sampling campaigns. The ratios between annual analyte concentrations in PM10 samples and in SRM 1649a were of the same order of magnitude although particulate matter samples analyzed were collected in two different sites and periods.

Addressing the Amorphous Content Issue in Quantitative Phase Analysis: The Certification of NIST Standard Reference Material 676a

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

J Cline; R Von Dreele; R Winburn

2011-12-31

A non-diffracting surface layer exists at any boundary of a crystal and can comprise a mass fraction of several percent in a finely divided solid. This has led to the long-standing issue of amorphous content in standards for quantitative phase analysis (QPA). NIST standard reference material (SRM) 676a is a corundum ({alpha}-Al{sub 2}O{sub 3}) powder, certified with respect to phase purity for use as an internal standard in powder diffraction QPA. The amorphous content of SRM 676a is determined by comparing diffraction data from mixtures with samples of silicon powders that were engineered to vary their specific surface area. Undermore » the (supported) assumption that the thickness of an amorphous surface layer on Si was invariant, this provided a method to control the crystalline/amorphous ratio of the silicon components of 50/50 weight mixtures of SRM 676a with silicon. Powder diffraction experiments utilizing neutron time-of-flight and 25 keV and 67 keV X-ray energies quantified the crystalline phase fractions from a series of specimens. Results from Rietveld analyses, which included a model for extinction effects in the silicon, of these data were extrapolated to the limit of zero amorphous content of the Si powder. The certified phase purity of SRM 676a is 99.02% {+-} 1.11% (95% confidence interval). This novel certification method permits quantification of amorphous content for any sample of interest, by spiking with SRM 676a.« less

Field Demonstration and Validation of a New Device for Measuring Water and Solute Fluxes at Naval Base Ventura County (NBVC), Port Hueneme, CA

DTIC Science & Technology

2006-07-01

All Quality Control Reference Materials are acquired only from authorized vendors or sources commonly used by U.S. EPA Regional Laboratories...are traceable to the National Institue of Standards and Testing (NITS) Standard Reference Materials (SRM) or to the U.S. EPA Reference Standards... clothing or equipment by blowing, shaking or any other means that may disperse material into the air is prohibited. 7.1.3. All disposable personal

Development of urine standard reference materials for metabolites of organic chemicals including polycyclic aromatic hydrocarbons, phthalates, phenols, parabens, and volatile organic compounds.

PubMed

Schantz, Michele M; Benner, Bruce A; Heckert, N Alan; Sander, Lane C; Sharpless, Katherine E; Vander Pol, Stacy S; Vasquez, Y; Villegas, M; Wise, Stephen A; Alwis, K Udeni; Blount, Benjamin C; Calafat, Antonia M; Li, Zheng; Silva, Manori J; Ye, Xiaoyun; Gaudreau, Éric; Patterson, Donald G; Sjödin, Andreas

2015-04-01

Two new Standard Reference Materials (SRMs), SRM 3672 Organic Contaminants in Smokers' Urine (Frozen) and SRM 3673 Organic Contaminants in Non-Smokers' Urine (Frozen), have been developed in support of studies for assessment of human exposure to select organic environmental contaminants. Collaborations among three organizations resulted in certified values for 11 hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and reference values for 11 phthalate metabolites, 8 environmental phenols and parabens, and 24 volatile organic compound (VOC) metabolites. Reference values are also available for creatinine and the free forms of caffeine, theobromine, ibuprofen, nicotine, cotinine, and 3-hydroxycotinine. These are the first urine Certified Reference Materials characterized for metabolites of organic environmental contaminants. Noteworthy, the mass fractions of the environmental organic contaminants in the two SRMs are within the ranges reported in population survey studies such as the National Health and Nutrition Examination Survey (NHANES) and the Canadian Health Measures Survey (CHMS). These SRMs will be useful as quality control samples for ensuring compatibility of results among population survey studies and will fill a void to assess the accuracy of analytical methods used in studies monitoring human exposure to these organic environmental contaminants.

Development of urine standard reference materials for metabolites of organic chemicals including polycyclic aromatic hydrocarbons, phthalates, phenols, parabens, and volatile organic compounds

PubMed Central

Schantz, Michele M.; Benner, Bruce A.; Heckert, N. Alan; Sander, Lane C.; Sharpless, Katherine E.; Vander Pol, Stacy S.; Vasquez, Y.; Villegas, M.; Wise, Stephen A.; Alwis, K. Udeni; Blount, Benjamin C.; Calafat, Antonia M.; Li, Zheng; Silva, Manori J.; Ye, Xiaoyun; Gaudreau, Éric; Patterson, Donald G.; Sjödin, Andreas

2016-01-01

Two new Standard Reference Materials (SRMs), SRM 3672 Organic Contaminants in Smokers’ Urine (Frozen) and SRM 3673 Organic Contaminants in Non-Smokers’ Urine (Frozen), have been developed in support of studies for assessment of human exposure to select organic environmental contaminants. Collaborations among three organizations resulted in certified values for 11 hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and reference values for 11 phthalate metabolites, 8 environmental phenols and parabens, and 24 volatile organic compound (VOC) metabolites. Reference values are also available for creatinine and the free forms of caffeine, theobromine, ibuprofen, nicotine, cotinine, and 3-hydroxycotinine. These are the first urine Certified Reference Materials characterized for metabolites of organic environmental contaminants. Noteworthy, the mass fractions of the environmental organic contaminants in the two SRMs are within the ranges reported in population survey studies such as the National Health and Nutrition Examination Survey (NHANES) and the Canadian Health Measures Survey (CHMS). These SRMs will be useful as quality control samples for ensuring compatibility of results among population survey studies and will fill a void to assess the accuracy of analytical methods used in studies monitoring human exposure to these organic environmental contaminants. PMID:25651899

Development and certification of the new SRM 695 trace elements in multi-nutrient fertilizer

USGS Publications Warehouse

MacKey, E.A.; Cronise, M.P.; Fales, C.N.; Greenberg, R.R.; Leigh, S.D.; Long, S.E.; Marlow, A.F.; Murphy, K.E.; Oflaz, R.; Sieber, J.R.; Rearick, M.S.; Wood, L.J.; Yu, L.L.; Wilson, S.A.; Briggs, P.H.; Brown, Z.A.; Budahn, J.; Kane, P.F.; Hall, W.L.

2007-01-01

During the past seven years, several states within the US have enacted regulations that limit the amounts of selected non-nutritive elements in fertilizers. Internationally, several countries, including Japan, China, and Australia, and the European Union also limit the amount of selected elements in fertilizers. The elements of interest include As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Se, and Zn. Fertilizer manufacturers and state regulatory authorities, faced with meeting and verifying these limits, need to develop analytical methods for determination of the elements of concern and to validate results obtained using these methods. Until now, there were no certified reference materials available with certified mass fraction values for all elements of interest in a blended, multi-nutrient fertilizer matrix. A new standard reference material (SRM) 695 trace elements in multi-nutrient fertilizer, has been developed to help meet these needs. SRM 695 has recently been issued with certified mass fraction values for seventeen elements, reference values for an additional five elements, and information values for two elements. The certificate of analysis includes an addendum listing percentage recovery for eight of these elements, determined using an acid-extraction inductively-coupled plasma optical-emission spectrometry (ICP-OES) method recently developed and tested by members of the Association of American Plant Food Control Officials. ?? Springer-Verlag 2007.

ALPHA SPECTROMETRIC EVALUATION OF SRM-995 AS A POTENTIAL URANIUM/THORIUM DOUBLE TRACER SYSTEM FOR AGE-DATING URANIUM MATERIALS

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

Beals, D.

2011-12-06

Uranium-233 (t{sub 1/2} {approx} 1.59E5 years) is an artificial, fissile isotope of uranium that has significant importance in nuclear forensics. The isotope provides a unique signature in determining the origin and provenance of uranium-bearing materials and is valuable as a mass spectrometric tracer. Alpha spectrometry was employed in the critical evaluation of a {sup 233}U standard reference material (SRM-995) as a dual tracer system based on the in-growth of {sup 229}Th (t{sub 1/2} {approx} 7.34E3 years) for {approx}35 years following radiochemical purification. Preliminary investigations focused on the isotopic analysis of standards and unmodified fractions of SRM-995; all samples were separatedmore » and purified using a multi-column anion-exchange scheme. The {sup 229}Th/{sup 233}U atom ratio for SRM-995 was found to be 1.598E-4 ({+-} 4.50%) using recovery-corrected radiochemical methods. Using the Bateman equations and relevant half-lives, this ratio reflects a material that was purified {approx} 36.8 years prior to this analysis. The calculated age is discussed in contrast with both the date of certification and the recorded date of last purification.« less

Application of laser ablation multicollector inductively coupled plasma mass spectrometry for the measurement of calcium and lead isotope ratios in packaging for discriminatory purposes.

PubMed

Santamaria-Fernandez, Rebeca; Wolff, Jean-Claude

2010-07-30

The potential of high-precision calcium and lead isotope ratio measurements using laser ablation coupled to multicollector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) to aid distinction between four genuine and five counterfeit pharmaceutical packaging samples and further classification of counterfeit packaging samples has been evaluated. We highlight the lack of reference materials for LA-MC-ICP-MS isotope ratio measurements in solids. In this case the problem is minimised by using National Institute of Standards and Technology Standard Reference Material (NIST SRM) 915a calcium carbonate (as solid pellets) and NIST SRM610 glass disc for sample bracketing external standardisation. In addition, a new reference material, NIST SRM915b calcium carbonate, has been characterised in-house for Ca isotope ratios and is used as a reference sample. Significant differences have been found between genuine and counterfeit samples; the method allows detection of counterfeits and aids further classification of packaging samples. Typical expanded uncertainties for measured-corrected Ca isotope ratio values ((43)Ca/(44)Ca and (42)Ca/(44)Ca) were found to be below 0.06% (k = 2, 95% confidence) and below 0.2% for measured-corrected Pb isotope ratios ((207)Pb/(206)Pb and (208)Pb/(206)Pb). This is the first time that Ca isotope ratios have been measured in packaging materials using LA coupled to a multicollector (MC)-ICP-MS instrument. The use of LA-MC-ICP-MS for direct measurement of Ca and Pb isotopic variations in cardboard/ink in packaging has definitive potential to aid counterfeit detection and classification. Copyright 2010 John Wiley & Sons, Ltd.

Preliminary characterisation of new glass reference materials (GSA-1G, GSC-1G, GSD-1G and GSE-1G) by laser ablation-inductively coupled plasma-mass spectrometry using 193 nm, 213 nm and 266 nm wavelengths

USGS Publications Warehouse

Guillong, M.; Hametner, K.; Reusser, E.; Wilson, S.A.; Gunther, D.

2005-01-01

New glass reference materials GSA-1G, GSC-1G, GSD-1G and GSE-1G have been characterised using a prototype solid state laser ablation system capable of producing wavelengths of 193 nm, 213 nm and 266 nm. This system allowed comparison of the effects of different laser wavelengths under nearly identical ablation and ICP operating conditions. The wavelengths 213 nm and 266 nm were also used at higher energy densities to evaluate the influence of energy density on quantitative analysis. In addition, the glass reference materials were analysed using commercially available 266 nm Nd:YAG and 193 nm ArF excimer lasers. Laser ablation analysis was carried out using both single spot and scanning mode ablation. Using laser ablation ICP-MS, concentrations of fifty-eight elements were determined with external calibration to the NIST SRM 610 glass reference material. Instead of applying the more common internal standardisation procedure, the total concentration of all element oxide concentrations was normalised to 100%. Major element concentrations were compared with those determined by electron microprobe. In addition to NIST SRM 610 for external calibration, USGS BCR-2G was used as a more closely matrix-matched reference material in order to compare the effect of matrix-matched and non matrix-matched calibration on quantitative analysis. The results show that the various laser wavelengths and energy densities applied produced similar results, with the exception of scanning mode ablation at 266 nm without matrix-matched calibration where deviations up to 60% from the average were found. However, results acquired using a scanning mode with a matrix-matched calibration agreed with results obtained by spot analysis. The increased abundance of large particles produced when using a scanning ablation mode with NIST SRM 610, is responsible for elemental fractionation effects caused by incomplete vaporisation of large particles in the ICP.

Isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS) for the certification of lead and cadmium in environmental standard reference materials.

PubMed

Murphy, K E; Beary, E S; Rearick, M S; Vocke, R D

2000-10-01

Lead (Pb) and cadmium (Cd) have been determined in six new environmental standard reference materials (SRMs) using isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS). The SRMs are the following: SRM 1944, New York-New Jersey Waterway Sediment, SRMs 2583 and 2584, Trace Elements in Indoor Dust, Nominal 90 mg/kg and 10,000 mg/kg Lead, respectively, SRMs 2586 and 2587, Trace Elements in Soil Containing Lead from Paint, Nominal 500 mg/kg and 3,000 mg/kg Lead, respectively, and SRM 2782, Industrial Sludge. The capabilities of ID ICP-MS for the certification of Pb and Cd in these materials are assessed. Sample preparation and ratio measurement uncertainties have been evaluated. Reproducibility and accuracy of the established procedures are demonstrated by determination of gravimetrically prepared primary standard solutions and by comparison with isotope dilution thermal ionization mass spectrometry (ID TIMS). Material heterogeneity was readily demonstrated to be the dominant source of uncertainty in the certified values.

Calibrating NIST SRM 683 as A New International Reference Standard for Zn Isotopes

NASA Astrophysics Data System (ADS)

Yang, Y.; Zhang, X.; Yu, H.; Huang, F.

2017-12-01

Zinc isotopes have been widely applied in the cosmochemical, geochemical, and environmental studies (Moynier et al. 2017). Obtaining precise Zn isotopic data for inter-laboratory comparison is a prerequisite to these applications. Currently, the JMC3-0749L is the primary reference standard for Zn isotopes (Albarède 2004), but it is not commercially available now. Thus, it is necessary to calibrate a new international primary reference standard for Zn isotopic analysis. Chen et al. (2016) showed that NIST SRM 683 (a pure Zn metal nugget of 140 grams) has a δ66ZnJMC of 0.12‰, which is falling within the range of natural Zn isotopic compositions, and it may a good candidate for the next generation of international reference standard (Chen et al. 2016). In order to further examine whether NIST SRM 683 has a homogeneous Zn isotopic composition, we measured more NIST SRM 683 by double-spike methods using MC-ICPMS (Conway et al. 2013). The metal nuggets of NIST SRM 683 were intensively sampled by micro-drilling. Zinc isotope analyses for two nuggets show that they have δ66Zn of 0.14 ± 0.02‰ (2SD, N = 32) and 0.13 ± 0.02‰ (2SD, N = 33), respectively. These values are similar to those of two Zn metal nuggets (0.11 ± 0.02‰ vs. 0.12 ± 0.02‰) reported previously by Chen et al. (2016). We fully dissolved one nugget, producing pure Zn solution with identical Zn isotopic composition with the drilling samples. All results strongly support that NIST SRM 683 is homogeneous in Zn isotopic compositions which could be an ideal candidate for the next reference for Zn isotopes. Tests on more metal nuggets will be performed in a few months for further confirming the Zn isotope compositions and homogeneity. Reference: Albarède et al., 2004. 'The stable isotope geochemistry of copper and zinc', Reviews in Mineralogy and Geochemistry, 55: 409-27. Chen et al., 2016. 'Zinc Isotopic Compositions of NIST SRM 683 and Whole-Rock Reference Materials', Geostandards and Geoanalytical Research, 40: 417-32. Conway et al., 2013. 'A new method for precise determination of iron, zinc and cadmium stable isotope ratios in seawater by double-spike mass spectrometry', Analytica chimica acta, 793: 44-52. Moynier et al., 2017. 'The isotope geochemistry of zinc and copper', Reviews in Mineralogy and Geochemistry, 82: 543-600.

Re-evaluation and extension of the scope of elements in US Geological Survey Standard Reference Water Samples

USGS Publications Warehouse

Peart, D.B.; Antweiler, Ronald C.; Taylor, Howard E.; Roth, D.A.; Brinton, T.I.

1998-01-01

More than 100 US Geological Survey (USGS) Standard Reference Water Samples (SRWSs) were analyzed for numerous trace constituents, including Al, As, B, Ba, Be, Bi, Br, Cd, Cr, Co, Cu, I, Fe, Pb, Li, Mn, Mo, Ni, Rb, Sb, Se, Sr, Te, Tl, U, V, Zn and major elements (Ca, Mg, Na, SiO2, SO4, Cl) by inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry. In addition, 15 USGS SRWSs and National Institute of Standards and Technology (NIST) standard reference material (SRM) 1641b were analyzed for mercury using cold vapor atomic fluorescence spectrometry. Also USGS SRWS Hg-7 was analyzed using isotope dilution-inductively coupled plasma mass spectrometry. The results were compared with the reported certified values of the following standard reference materials: NIST SRM 1643a, 1643b, 1643c and 1643d and National Research Council of Canada Riverine Water Reference Materials for Trace Metals SLRS-1, SLRS-2 and SLRS-3. New concentration values for trace and major elements in the SRWSs, traceable to the certified standards, are reported. Additional concentration values are reported for elements that were neither previously published for the SRWSs nor traceable to the certified reference materials. Robust statistical procedures were used that were insensitive to outliers. These data can be used for quality assurance/quality control purposes in analytical laboratories.

Establishing the traceability of a uranyl nitrate solution to a standard reference material

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

Jackson, C.H.; Clark, J.P.

1978-01-01

A uranyl nitrate solution for use as a Working Calibration and Test Material (WCTM) was characterized, using a statistically designed procedure to document traceability to National Bureau of Standards Reference Material (SPM-960). A Reference Calibration and Test Material (PCTM) was prepared from SRM-960 uranium metal to approximate the acid and uranium concentration of the WCTM. This solution was used in the characterization procedure. Details of preparing, handling, and packaging these solutions are covered. Two outside laboratories, each having measurement expertise using a different analytical method, were selected to measure both solutions according to the procedure for characterizing the WCTM. Twomore » different methods were also used for the in-house characterization work. All analytical results were tested for statistical agreement before the WCTM concentration and limit of error values were calculated. A concentration value was determined with a relative limit of error (RLE) of approximately 0.03% which was better than the target RLE of 0.08%. The use of this working material eliminates the expense of using SRMs to fulfill traceability requirements for uranium measurements on this type material. Several years' supply of uranyl nitrate solution with NBS traceability was produced. The cost of this material was less than 10% of an equal quantity of SRM-960 uranium metal.« less

Production and certification of NIST Standard Reference Material 2372 Human DNA Quantitation Standard.

PubMed

Kline, Margaret C; Duewer, David L; Travis, John C; Smith, Melody V; Redman, Janette W; Vallone, Peter M; Decker, Amy E; Butler, John M

2009-06-01

Modern highly multiplexed short tandem repeat (STR) assays used by the forensic human-identity community require tight control of the initial amount of sample DNA amplified in the polymerase chain reaction (PCR) process. This, in turn, requires the ability to reproducibly measure the concentration of human DNA, [DNA], in a sample extract. Quantitative PCR (qPCR) techniques can determine the number of intact stretches of DNA of specified nucleotide sequence in an extremely small sample; however, these assays must be calibrated with DNA extracts of well-characterized and stable composition. By 2004, studies coordinated by or reported to the National Institute of Standards and Technology (NIST) indicated that a well-characterized, stable human DNA quantitation certified reference material (CRM) could help the forensic community reduce within- and among-laboratory quantitation variability. To ensure that the stability of such a quantitation standard can be monitored and that, if and when required, equivalent replacement materials can be prepared, a measurement of some stable quantity directly related to [DNA] is required. Using a long-established conventional relationship linking optical density (properly designated as decadic attenuance) at 260 nm with [DNA] in aqueous solution, NIST Standard Reference Material (SRM) 2372 Human DNA Quantitation Standard was issued in October 2007. This SRM consists of three quite different DNA extracts: a single-source male, a multiple-source female, and a mixture of male and female sources. All three SRM components have very similar optical densities, and thus very similar conventional [DNA]. The materials perform very similarly in several widely used gender-neutral assays, demonstrating that the combination of appropriate preparation methods and metrologically sound spectrophotometric measurements enables the preparation and certification of quantitation [DNA] standards that are both maintainable and of practical utility.

Development of an accurate, sensitive, and robust isotope dilution laser ablation ICP-MS method for simultaneous multi-element analysis (chlorine, sulfur, and heavy metals) in coal samples.

PubMed

Boulyga, Sergei F; Heilmann, Jens; Prohaska, Thomas; Heumann, Klaus G

2007-10-01

A method for the direct multi-element determination of Cl, S, Hg, Pb, Cd, U, Br, Cr, Cu, Fe, and Zn in powdered coal samples has been developed by applying inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with laser-assisted introduction into the plasma. A sector-field ICP-MS with a mass resolution of 4,000 and a high-ablation rate laser ablation system provided significantly better sensitivity, detection limits, and accuracy compared to a conventional laser ablation system coupled with a quadrupole ICP-MS. The sensitivity ranges from about 590 cps for (35)Cl+ to more than 6 x 10(5) cps for (238)U+ for 1 microg of trace element per gram of coal sample. Detection limits vary from 450 ng g(-1) for chlorine and 18 ng g(-1) for sulfur to 9.5 pg g(-1) for mercury and 0.3 pg g(-1) for uranium. Analyses of minor and trace elements in four certified reference materials (BCR-180 Gas Coal, BCR-331 Steam Coal, SRM 1632c Trace Elements in Coal, SRM 1635 Trace Elements in Coal) yielded good agreement of usually not more than 5% deviation from the certified values and precisions of less than 10% relative standard deviation for most elements. Higher relative standard deviations were found for particular elements such as Hg and Cd caused by inhomogeneities due to associations of these elements within micro-inclusions in coal which was demonstrated for Hg in SRM 1635, SRM 1632c, and another standard reference material (SRM 2682b, Sulfur and Mercury in Coal). The developed LA-ICP-IDMS method with its simple sample pretreatment opens the possibility for accurate, fast, and highly sensitive determinations of environmentally critical contaminants in coal as well as of trace impurities in similar sample materials like graphite powder and activated charcoal on a routine basis.

Determination of serum calcium levels by 42Ca isotope dilution inductively coupled plasma mass spectrometry.

PubMed

Han, Bingqing; Ge, Menglei; Zhao, Haijian; Yan, Ying; Zeng, Jie; Zhang, Tianjiao; Zhou, Weiyan; Zhang, Jiangtao; Wang, Jing; Zhang, Chuanbao

2017-11-27

Serum calcium level is an important clinical index that reflects pathophysiological states. However, detection accuracy in laboratory tests is not ideal; as such, a high accuracy method is needed. We developed a reference method for measuring serum calcium levels by isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS), using 42Ca as the enriched isotope. Serum was digested with 69% ultrapure nitric acid and diluted to a suitable concentration. The 44Ca/42Ca ratio was detected in H2 mode; spike concentration was calibrated by reverse IDMS using standard reference material (SRM) 3109a, and sample concentration was measured by a bracketing procedure. We compared the performance of ID ICP-MS with those of three other reference methods in China using the same serum and aqueous samples. The relative expanded uncertainty of the sample concentration was 0.414% (k=2). The range of repeatability (within-run imprecision), intermediate imprecision (between-run imprecision), and intra-laboratory imprecision were 0.12%-0.19%, 0.07%-0.09%, and 0.16%-0.17%, respectively, for two of the serum samples. SRM909bI, SRM909bII, SRM909c, and GBW09152 were found to be within the certified value interval, with mean relative bias values of 0.29%, -0.02%, 0.10%, and -0.19%, respectively. The range of recovery was 99.87%-100.37%. Results obtained by ID ICP-MS showed a better accuracy than and were highly correlated with those of other reference methods. ID ICP-MS is a simple and accurate candidate reference method for serum calcium measurement and can be used to establish and improve serum calcium reference system in China.

Sample characterization of automobile and forklift diesel exhaust particles and comparative pulmonary toxicity in mice.

PubMed

Singh, Pramila; DeMarini, David M; Dick, Colin A J; Tabor, Dennis G; Ryan, Jeff V; Linak, William P; Kobayashi, Takahiro; Gilmour, M Ian

2004-06-01

Two samples of diesel exhaust particles (DEPs) predominate in health effects research: an automobile-derived DEP (A-DEP) sample and the National Institute of Standards Technology standard reference material (SRM 2975) generated from a forklift engine. A-DEPs have been tested extensively for their effects on pulmonary inflammation and exacerbation of allergic asthmalike responses. In contrast, SRM 2975 has been tested thoroughly for its genotoxicity. In the present study, we combined physical and chemical analyses of both DEP samples with pulmonary toxicity testing in CD-1 mice to compare the two materials and to make associations between their physicochemical properties and their biologic effects. A-DEPs had more than 10 times the amount of extractable organic material and less than one-sixth the amount of elemental carbon compared with SRM 2975. Aspiration of 100 micro g of either DEP sample in saline produced mild acute lung injury; however, A-DEPs induced macrophage influx and activation, whereas SRM 2975 enhanced polymorphonuclear cell inflammation. A-DEPs stimulated an increase in interleukin-6 (IL-6), tumor necrosis factor alpha, macrophage inhibitory protein-2, and the TH2 cytokine IL-5, whereas SRM 2975 only induced significant levels of IL-6. Fractionated organic extracts of the same quantity of DEPs (100 micro g) did not have a discernable effect on lung responses and will require further study. The disparate results obtained highlight the need for chemical, physical, and source characterization of particle samples under investigation. Multidisciplinary toxicity testing of diesel emissions derived from a variety of generation and collection conditions is required to meaningfully assess the health hazards associated with exposures to DEPs. Key words: automobile, diesel exhaust particles, forklift, mice, pulmonary toxicity, SRM 2975.

Sample characterization of automobile and forklift diesel exhaust particles and comparative pulmonary toxicity in mice.

PubMed Central

Singh, Pramila; DeMarini, David M; Dick, Colin A J; Tabor, Dennis G; Ryan, Jeff V; Linak, William P; Kobayashi, Takahiro; Gilmour, M Ian

2004-01-01

Two samples of diesel exhaust particles (DEPs) predominate in health effects research: an automobile-derived DEP (A-DEP) sample and the National Institute of Standards Technology standard reference material (SRM 2975) generated from a forklift engine. A-DEPs have been tested extensively for their effects on pulmonary inflammation and exacerbation of allergic asthmalike responses. In contrast, SRM 2975 has been tested thoroughly for its genotoxicity. In the present study, we combined physical and chemical analyses of both DEP samples with pulmonary toxicity testing in CD-1 mice to compare the two materials and to make associations between their physicochemical properties and their biologic effects. A-DEPs had more than 10 times the amount of extractable organic material and less than one-sixth the amount of elemental carbon compared with SRM 2975. Aspiration of 100 micro g of either DEP sample in saline produced mild acute lung injury; however, A-DEPs induced macrophage influx and activation, whereas SRM 2975 enhanced polymorphonuclear cell inflammation. A-DEPs stimulated an increase in interleukin-6 (IL-6), tumor necrosis factor alpha, macrophage inhibitory protein-2, and the TH2 cytokine IL-5, whereas SRM 2975 only induced significant levels of IL-6. Fractionated organic extracts of the same quantity of DEPs (100 micro g) did not have a discernable effect on lung responses and will require further study. The disparate results obtained highlight the need for chemical, physical, and source characterization of particle samples under investigation. Multidisciplinary toxicity testing of diesel emissions derived from a variety of generation and collection conditions is required to meaningfully assess the health hazards associated with exposures to DEPs. Key words: automobile, diesel exhaust particles, forklift, mice, pulmonary toxicity, SRM 2975. PMID:15175167

On the isolation of elemental carbon for micro-molar 14C accelerator mass spectrometry; evaluation of alternative isolation procedures, and accuracy assurance using a hybrid isotopic particulate carbon reference material

NASA Astrophysics Data System (ADS)

Currie, L. A.; Kessler, J. D.

2005-05-01

The primary objective of the research reported here has been the development of an hybrid reference material (RM) to serve as a test of accuracy for elemental carbon (EC) isotopic (14C) speciation measurements. Such measurements are critically important for the quantitative apportionment of fossil and biomass sources of ''soot'' (EC), the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust), showed a range of results, but since the ''truth'' was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence (14C in PAH, EC) of measurement validity (Currie et al., 2002). Components of the new Hybrid RM (DiesApple), however, have known 14C and EC composition, and they are nearly orthogonal (isotopically and chemically). NIST SRM 2975 (Forklift Diesel Soot) has little or no 14C, and its major compositional component is EC. SRM 1515 (Apple Leaves) has the 14C content of biomass-C, and it has little or no EC. Thus, the hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C from SRM 1515 in the EC isolate of the hybrid RM, together with testing for conservation of its dominant soot fraction through the isolation procedure.

A comparative study of 129I content in environmental standard materials IAEA-375, NIST SRM 4354 and NIST SRM 4357 by Thermal Ionization Mass Spectrometry and Accelerator Mass Spectrometry

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

Olson, John; Adamic, Mary; Snyder, Darin

Iodine environmental measurements have consistently been backed up in the literature by standard materials like IAEA-375, Chernobyl Soil. There are not many other sources of a certified reference material for 129I content for mass spectrometry measurements. Some that have been found in the literature include NIST-4354 and NIST-4357. They are still available at the time of this writing. They don’t have certified content or isotopic values. There has been some work in the literature to show that iodine is present, but there hasn’t been enough to establish a consensus value. These materials have been analyzed at INL through two separatemore » mass spectrometry techniques. They involve a combustion method of the starting material in oxygen, followed by TIMS analysis and a leaching preparation analyzed by accelerator mass spectrometry. Combustion/TIMS preparation of NIST SRM-4354 resulted in a 129I/127I ratio of 1.92 x 10-6 which agrees with AMS measurements which measured the 129I/127I ratio to be 1.93 x 10-6.« less

Multi-scale analysis of the occurrence of Pb, Cr and Mn in the NIST standards: Urban dust (SRM 1649a) and indoor dust (SRM 2584)

NASA Astrophysics Data System (ADS)

Jiang, Mingyu; Nakamatsu, Yuki; Jensen, Keld A.; Utsunomiya, Satoshi

2014-01-01

Adverse health effects of ambient particulate matters are closely related to the speciation of the constituting organic matters and toxic metals. To determine multi-parameters of the metal speciation in urban and indoor dusts, we have performed systematic bulk- to nano-scale (“multi-scale”) analysis on the speciation of Pb, Mn, and Cr in two National Institute of Standards and Technology (NIST) standard reference materials (SRMs): urban dust (SRM 1649a) and indoor dust (SRM 2584), utilizing X-ray absorption near-edge structure, powder X-ray diffraction analysis, electron microprobe analysis, scanning electron microscopy, and transmission electron microscopy. Major crystalline phases are quartz, gypsum, kaolinite, and muscovite in SRM 1649a, while quartz, gypsum, calcite, and possibly muscovite (or chabazite) in SRM 2584. A number of Pb sulfate nanoparticles (50-200 nm) occur in SRM 1649a, whereas micron-sized Pb carbonate is present containing various concentrations of Zn and Ti in the complex texture in SRM 2584. Relatively soluble Mn(II) sulfate is the bulk-averaged Mn speciation in SRM 1649a, although discrete Mn sulfate particles are not characterized by individual particle analysis, implying the diluted Mn distribution within other sulfate. In SRM 2584, Mn speciation includes a mixture of oxides and carbonates, and trace Mn in chromite. Chromite (FeCr2O4) is the major Cr speciation in SRM1694a, while unidentified Cr(III) phases with minor chromite and Pb chromate are present in SRM 2584, among which the Pb chromate is composed of Cr(VI). A significant number of the metal-bearing particles are distributed to the submicron-size fraction in the urban dust, SRM 1649a, suggesting that these metal nanoparticles can potentially penetrate into the deep respiratory system. This study demonstrates that multi-scale analysis combining nano and bulk analytical techniques is a powerful approach to investigate the multi-parameters of metal-bearing nanoparticles in heterogeneous PM samples.

Activity measurements of a suite of radionuclides (241Am, 239,240Pu, 238Pu, 238U, 234U, 235U, 232Th, 230Th, 228Th, 228Ra, 137Cs, 210Pb, 90Sr and 40K) in biota reference material (Ocean Shellfish): CCRI(II)-S3

NASA Astrophysics Data System (ADS)

Nour, S.; Karam, L. R.; Inn, K. G. W.

2012-01-01

In 2005, the CCRI decided that a comparison undertaken from 2002 to 2008 by the NIST (under the auspices of the Inter-America Metrology System [SIM]) in the development of a new biota (Ocean Shellfish) standard reference material (SRM) was sufficiently well constructed that it could be converted into a supplementary comparison under CCRI(II), with comparison identifier CCRI(II)-S3. This would enable the comparison to be used to support calibration and measurement capability (CMC) claims for radionuclide measurements in reference materials (specifically, animal-based organic materials). Previous comparisons of radionuclides have been of single or multiple nuclides in non-complex matrices and results of such could not be extended to support capabilities to measure the same nuclides in reference materials. The results of this comparison have been used to determine the certified reference value of the SRM. The key comparison working group (KCWG) of the CCRI(II) has approved this approach as a mechanism to link all the results to certified 'reference values' in lieu of the key comparison reference value (KCRV) of these specified radionuclides in this type of matrix (shellfish) so as to support CMCs of similar materials submitted by the present participants. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

LipidQC: Method Validation Tool for Visual Comparison to SRM 1950 Using NIST Interlaboratory Comparison Exercise Lipid Consensus Mean Estimate Values.

PubMed

Ulmer, Candice Z; Ragland, Jared M; Koelmel, Jeremy P; Heckert, Alan; Jones, Christina M; Garrett, Timothy J; Yost, Richard A; Bowden, John A

2017-12-19

As advances in analytical separation techniques, mass spectrometry instrumentation, and data processing platforms continue to spur growth in the lipidomics field, more structurally unique lipid species are detected and annotated. The lipidomics community is in need of benchmark reference values to assess the validity of various lipidomics workflows in providing accurate quantitative measurements across the diverse lipidome. LipidQC addresses the harmonization challenge in lipid quantitation by providing a semiautomated process, independent of analytical platform, for visual comparison of experimental results of National Institute of Standards and Technology Standard Reference Material (SRM) 1950, "Metabolites in Frozen Human Plasma", against benchmark consensus mean concentrations derived from the NIST Lipidomics Interlaboratory Comparison Exercise.

Certification by the Karl Fischer method of the water content in SRM 2890, Water Saturated 1-Octanol, and the analysis of associated interlaboratory bias in the measurement process.

PubMed

Margolis, S A; Levenson, M

2000-05-01

The calibration of Karl Fischer instruments and reagents and the compensation for instrumental bias are essential to the accurate measurement of trace levels of water in organic and inorganic chemicals. A stable, nonhygroscopic standard, Water Saturated Octanol, which is compatible with the Karl Fischer reagents, has been prepared. This material, Standard Reference Material (SRM) 2890, is homogeneous and is certified to contain 39.24 +/- 0.85 mg water/mL (expanded uncertainty) of solution (47.3 +/- 1.0 mg water/g solution, expanded uncertainty) at 21.5 degrees C. The solubility of water in -octanol has been shown to be nearly constant between 10 degrees C and 30 degrees C (i.e., within 1% of the value at 21.5 degrees C). The results of an interlaboratory comparison exercise illustrate the utility of SRM 2890 in assessing the accuracy and bias of Karl Fischer instruments and measurements.

Trace level voltammetric determination of heavy metals and total mercury in tea matrices (Camellia sinensis).

PubMed

Melucci, Dora; Locatelli, Marcello; Locatelli, Clinio

2013-12-01

An analytical procedure regarding the voltammetric determination of mercury(II), copper(II), lead(II), cadmium(II) and zinc(II) by square wave anodic stripping voltammetry (SWASV) in matrices involved in food chain is proposed. In particular, tea leaves were analyzed as real samples. The digestion of each matrix was carried out using a concentrated HCl-HNO3-H2SO4 acidic attack mixture; 0.01 mol L(-1) EDTA-Na2+ 0.15 mol L(-1) NaCl + 0.5 mol L(-1) HCl was employed as the supporting electrolyte. The voltammetric measurements were carried out using a conventional three electrode cell, employing, as working electrodes, a gold electrode (GE) and a stationary hanging mercury drop electrode (HMDE). The analytical procedure has been verified on the standard reference materials Spinach Leaves NIST-SRM 1570a, Tomato Leaves NIST-SRM 1573a and Apple Leaves NIST-SRM 1515. For all the elements, the precision as repeatability, expressed as relative standard deviation (sr) was of the order of 3-5%, while the trueness, expressed as relative error (e) was of the order of 3-7%. Once set up on the standard reference materials, the analytical procedure was applied to commercial tea leaves samples. A critical comparison with spectroscopic measurements is also discussed.

Evaluation of laser ablation double-focusing SC-ICPMS for “common” lead isotopic measurements in silicate glasses and mineral

USGS Publications Warehouse

Pietruszka, Aaron J.; Neymark, Leonid

2017-01-01

An analytical method for the in situ measurement of “common” Pb isotope ratios in silicate glasses and minerals using a 193-nm excimer laser ablation (LA) system with a double-focusing single-collector (SC)-ICPMS is presented and evaluated as a possible alternative to multiple-collector (MC)-ICPMS. This LA-SC-ICPMS technique employs fast-scanning ion deflectors to sequentially place a series of flat-topped isotope peaks into a single ion-counting detector at a fixed accelerating voltage and magnetic field strength. Reference materials (including NIST, MPI-DING, and USGS glasses) are used to identify two analytical artifacts on the Pb isotope ratios (expressed here as heavier/lighter isotopes) when corrected for mass bias relative to NIST SRM610. The first artifact is characterized by anomalously low Pb isotope ratios (~0.1%/AMU) when SRM610 is analyzed in raster mode as an unknown at small spot sizes (<25 µm), which may indicate that (1) SRM610 is isotopically heterogeneous on a small length scale and/or (2) there is a non-spectral matrix effect on the Pb isotope ratios related to differences in spot size. The second artifact is characterized by anomalously high Pb isotope ratios (<0.1%/AMU) for NIST SRM612 (in raster mode) and some Fe-rich glass reference materials (BCR-2G, GOR132-G, and T1-G). These offsets are thought to be caused by one or more non-spectral matrix effects related to differences in the ablation behavior, composition, or physical properties of these reference materials compared to the bracketing SRM610 standard. The precision (±2SD) of our LA-SC-ICPMS Pb isotopic measurements is similar to (207Pb/206Pb and 208Pb/206Pb, or 20XPb/206Pb) or better than (206Pb/204Pb,207Pb/204Pb, and 208Pb/204Pb, or 20XPb/204Pb) a series of published studies that used a different type of SC-ICPMS and obtained a factor of ~3-4 higher sensitivity for Pb. An increase in the sensitivity of our LA-SC-ICPMS would likely improve the precision of the 20XPb/206Pb and 20XPb/204Pb ratios for low-Pb materials (<5 ppm), possibly making the technique broadly similar to LA-MC-ICPMS (particularly compared to methods that rely upon at least one ion-counting detector). Further improvement in the precision of the 20XPb/206Pb and 20XPb/204Pb ratios for high-Pb materials (>5 ppm) by LA-SC-ICPMS is unlikely, and in this case, LA-MC-ICPMS remains the preferable analytical technique.

The National Ballistics Imaging Comparison (NBIC) project.

PubMed

Song, J; Vorburger, T V; Ballou, S; Thompson, R M; Yen, J; Renegar, T B; Zheng, A; Silver, R M; Ols, M

2012-03-10

In response to the guidelines issued by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB-International) to establish traceability and quality assurance in U.S. crime laboratories, a NIST/ATF joint project entitled National Ballistics Imaging Comparison (NBIC) was initialized in 2008. The NBIC project aims to establish a National Traceability and Quality System for ballistics identifications in crime laboratories within the National Integrated Ballistics Information Network (NIBIN) of the U.S. NIST Standard Reference Material (SRM) 2460 bullets and 2461 cartridge cases are used as reference standards. 19 ballistics examiners from 13 U.S. crime laboratories participated in this project. They each performed 24 periodic image acquisitions and correlations of the SRM bullets and cartridge cases over the course of a year, but one examiner only participated in Phase 1 tests of SRM cartridge case. The correlation scores were collected by NIST for statistical analyses, from which control charts and control limits were developed for the proposed Quality System and for promoting future assessments and accreditations for firearm evidence in U.S. forensic laboratories in accordance with the ISO 17025 Standard. Published by Elsevier Ireland Ltd.

Certified reference materials (GBW09170 and 09171) of creatinine in human serum.

PubMed

Dai, Xinhua; Fang, Xiang; Shao, Mingwu; Li, Ming; Huang, Zejian; Li, Hongmei; Jiang, You; Song, Dewei; He, Yajuan

2011-02-15

Creatinine is the most widely used clinical marker for assessing renal function. Concentrations of creatinine in human serum need to be carefully checked in order to ensure accurate diagnosis of renal function. Therefore, development of certified reference materials (CRMs) of creatinine in serum is of increasing importance. In this study, two new CRMs (Nos. GBW09170 and 09171) for creatinine in human serum have been developed. They were prepared with mixtures of several dozens of healthy people's and kidney disease patient's serum, respectively. The certified values of 8.10, 34.1 mg/kg for these two CRMs have been assigned by liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) method which was validated by using standard reference material (SRM) of SRM909b (a reference material obtained from National Institute of Standards and Technology, NIST). The expanded uncertainties of certified values for low and high concentrations were estimated to be 1.2 and 1.1%, respectively. The certified values were further confirmed by an international intercomparison for the determination of creatinine in human serum (Consultative Committee for Amount of Substance, CCQM) of K80 (CCQM-K80). These new CRMs of creatinine in human serum pool are totally native without additional creatinine spiked for enrichment. These new CRMs are capable of validating routine clinical methods for ensuring accuracy, reliability and comparability of analytical results from different clinical laboratories. They can also be used for instrument validation, development of secondary reference materials, and evaluating the accuracy of high order clinical methods for the determination of creatinine in human serum. Copyright © 2011 Elsevier B.V. All rights reserved.

Standard Reference Materials (SRMs) for the Calibration and Validation of Analytical Methods for PCBs (as Aroclor Mixtures)

PubMed Central

Poster, Dianne L.; Schantz, Michele M.; Leigh, Stefan D.; Wise, Stephen A.

2004-01-01

Six Standard Reference Materials (SRMs®) have been prepared by the National Institute of Standards and Technology (NIST) for the determination of PCBs as different Aroclor mixtures in methanol. Six additional SRMs of the same Aroclors in transformer oil have also been prepared. Specifically, solutions of Aroclors 1016, 1232, 1242, 1254, and 1260 have been gravimetrically prepared (individually) in methanol and transformer oil, mixed, and transferred to amber glass ampoules in approximately 1.2 mL aliquots. Gas chromatography with electron capture detection (GC-ECD) has been used to verify the gravimetric data for each solution and transformer oil SRM. Liquid chromatography was used for the isolation of the Aroclors from the transformer oil SRMs prior to GC-ECD analysis. Separate calibration solutions and oils were prepared with Aroclor levels similar to those in each methanol solution and transformer oil SRM and were processed alongside the samples. The GC-ECD response of each Aroclor was monitored relative to internal standards that were added to the complex mixtures for quantification. The gravimetric concentrations of Aroclors 1242 and 1254 in methanol were also examined by the same method of analysis (GC-ECD) using several different sources of Aroclors and two different capillary GC columns: a 5 % phenyl methylpolysiloxane phase and a relatively non-polar phase. The preparation of the materials, the gas chromatographic results, and the certified concentration values for each Aroclor SRM are described in this paper. PMID:27366608

CPTC and NIST-sponsored Yeast Reference Material Now Publicly Available | Office of Cancer Clinical Proteomics Research

Cancer.gov

The yeast protein extract (RM8323) developed by National Institute of Standards and Technology (NIST) under the auspices of NCI's CPTC initiative is currently available to the public at https://www-s.nist.gov/srmors/view_detail.cfm?srm=8323. The yeast proteome offers researchers a unique biological reference material. RM8323 is the most extensively characterized complex biological proteome and the only one associated with several large-scale studies to estimate protein abundance across a wide concentration range.

Determination of elemental carbon in lake sediments using a thermal-optical transmittance (TOT) method

NASA Astrophysics Data System (ADS)

Khan, A. J.; Swami, Kamal; Ahmed, Tanveer; Bari, A.; Shareef, Akhtar; Husain, Liaquat

2009-12-01

An improved chemical oxidation pretreatment method has been developed for the determination of elemental carbon (EC) [also known as black carbon (BC) or soot] in lake sediments, using a thermal-optical transmittance (TOT) carbon analyzer. The method employs six steps: (1) removal of carbonates by treatment with HCl; (2) removal of silicates by treatment with HF + HCl; (3) removal of any remaining carbonates by treatment with HCl; (4) removal of humic acids by treatment with NaOH; and (5) oxidation of kerogens by K 2Cr 2O 7 + H 2SO 4. A critical step of zinc chloride treatment was added; this apparently changes EC's morphology and enhances retention on quartz fiber filter, resulting in several-fold increased chemical yield. EC was determined using the TOT method with modified combustion timings. Carbon black (acetylene) and four NIST standard reference materials (SRMs) were used for quality control, and to assess the precision of the analysis. The EC recoveries from 18 carbon black samples varied from 90 to 111%, with a mean value of 99 ± 6%. The high EC recoveries confirmed the validity of the method. Char reference materials (i.e. chestnut wood and grass char) were used to determine potential contribution to EC in our measurements. The char references containing about 700 mg total organic carbon (OC) contributed ˜1.5% EC. The measured EC values from four NIST standards were 17.0 ± 0.6, 24.2 ± 3.2, 5.6, and 1.9 ± 0.1 mg g dw-1 for SRM-1648, SRM-1649a, SRM-1941b and SRM-8704, respectively. These values in SRMs were in agreement (<±4%) with the previously reported values. The method was applied to determine the EC in sediment cores from an urban lake and a remote mountain lake in the Northeastern United States. The EC concentrations in two lakes mimic the model EC emissions from the industrial revolution in United States.

LA-ICP-MS of magnetite: Methods and reference materials

USGS Publications Warehouse

Nadoll, P.; Koenig, A.E.

2011-01-01

Magnetite (Fe3O4) is a common accessory mineral in many geologic settings. Its variable geochemistry makes it a powerful petrogenetic indicator. Electron microprobe (EMPA) analyses are commonly used to examine major and minor element contents in magnetite. Laser ablation ICP-MS (LA-ICP-MS) is applicable to trace element analyses of magnetite but has not been widely employed to examine compositional variations. We tested the applicability of the NIST SRM 610, the USGS GSE-1G, and the NIST SRM 2782 reference materials (RMs) as external standards and developed a reliable method for LA-ICP-MS analysis of magnetite. LA-ICP-MS analyses were carried out on well characterized magnetite samples with a 193 nm, Excimer, ArF LA system. Although matrix-matched RMs are sometimes important for calibration and normalization of LA-ICP-MS data, we demonstrate that glass RMs can produce accurate results for LA-ICP-MS analyses of magnetite. Cross-comparison between the NIST SRM 610 and USGS GSE-1G indicates good agreement for magnetite minor and trace element data calibrated with either of these RMs. Many elements show a sufficiently good match between the LA-ICP-MS and the EMPA data; for example, Ti and V show a close to linear relationship with correlation coefficients, R2 of 0.79 and 0.85 respectively. ?? 2011 The Royal Society of Chemistry.

Retrospective Analysis of NIST Standard Reference Material 1450, Fibrous Glass Board, for Thermal Insulation Measurements.

PubMed

Zarr, Robert R; Heckert, N Alan; Leigh, Stefan D

2014-01-01

Thermal conductivity data acquired previously for the establishment of Standard Reference Material (SRM) 1450, Fibrous Glass Board, as well as subsequent renewals 1450a, 1450b, 1450c, and 1450d, are re-analyzed collectively and as individual data sets. Additional data sets for proto-1450 material lots are also included in the analysis. The data cover 36 years of activity by the National Institute of Standards and Technology (NIST) in developing and providing thermal insulation SRMs, specifically high-density molded fibrous-glass board, to the public. Collectively, the data sets cover two nominal thicknesses of 13 mm and 25 mm, bulk densities from 60 kg·m(-3) to 180 kg·m(-3), and mean temperatures from 100 K to 340 K. The analysis repetitively fits six models to the individual data sets. The most general form of the nested set of multilinear models used is given in the following equation: [Formula: see text]where λ(ρ,T) is the predicted thermal conductivity (W·m(-1)·K(-1)), ρ is the bulk density (kg·m(-3)), T is the mean temperature (K) and ai (for i = 1, 2, … 6) are the regression coefficients. The least squares fit results for each model across all data sets are analyzed using both graphical and analytic techniques. The prevailing generic model for the majority of data sets is the bilinear model in ρ and T. [Formula: see text] One data set supports the inclusion of a cubic temperature term and two data sets with low-temperature data support the inclusion of an exponential term in T to improve the model predictions. Physical interpretations of the model function terms are described. Recommendations for future renewals of SRM 1450 are provided. An Addendum provides historical background on the origin of this SRM and the influence of the SRM on external measurement programs.

Development of a highly precise ID-ICP-SFMS method for analysis of low concentrations of lead in rice flour reference materials.

PubMed

Zhu, Yanbei; Inagaki, Kazumi; Yarita, Takashi; Chiba, Koichi

2008-07-01

Microwave digestion and isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-SFMS) has been applied to the determination of Pb in rice flour. In order to achieve highly precise determination of low concentrations of Pb, the digestion blank for Pb was reduced to 0.21 ng g(-1) after optimization of the digestion conditions, in which 20 mL analysis solution was obtained after digestion of 0.5 g rice flour. The observed value of Pb in a non-fat milk powder certified reference material (CRM), NIST SRM 1549, was 16.8 +/- 0.8 ng g(-1) (mean +/- expanded uncertainty, k = 2; n = 5), which agreed with the certified value of 19 +/- 3 ng g(-1) and indicated the effectiveness of the method. Analytical results for Pb in three brown rice flour CRMs, NIST SRM 1568a, NIES CRM 10-a, and NIES CRM 10-b, were 7.32 +/- 0.24 ng g(-1) (n = 5), 1010 +/- 10 ng g(-1) (n = 5), and 1250 +/- 20 ng g(-1) (n = 5), respectively. The concentration of Pb in a candidate white rice flour reference material (RM) sample prepared by the National Metrology Institute of Japan (NMIJ) was observed to be 4.36 +/- 0.28 ng g(-1) (n = 10 bottles).

Utilization of optimized BCR three-step sequential and dilute HCl single extraction procedures for soil-plant metal transfer predictions in contaminated lands.

PubMed

Kubová, Jana; Matús, Peter; Bujdos, Marek; Hagarová, Ingrid; Medved', Ján

2008-05-30

The prediction of soil metal phytoavailability using the chemical extractions is a conventional approach routinely used in soil testing. The adequacy of such soil tests for this purpose is commonly assessed through a comparison of extraction results with metal contents in relevant plants. In this work, the fractions of selected risk metals (Al, As, Cd, Cu, Fe, Mn, Ni, Pb, Zn) that can be taken up by various plants were obtained by optimized BCR (Community Bureau of Reference) three-step sequential extraction procedure (SEP) and by single 0.5 mol L(-1) HCl extraction. These procedures were validated using five soil and sediment reference materials (SRM 2710, SRM 2711, CRM 483, CRM 701, SRM RTH 912) and applied to significantly different acidified soils for the fractionation of studied metals. The new indicative values of Al, Cd, Cu, Fe, Mn, P, Pb and Zn fractional concentrations for these reference materials were obtained by the dilute HCl single extraction. The influence of various soil genesis, content of essential elements (Ca, Mg, K, P) and different anthropogenic sources of acidification on extraction yields of individual risk metal fractions was investigated. The concentrations of studied elements were determined by atomic spectrometry methods (flame, graphite furnace and hydride generation atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry). It can be concluded that the data of extraction yields from first BCR SEP acid extractable step and soil-plant transfer coefficients can be applied to the prediction of qualitative mobility of selected risk metals in different soil systems.

Some issues for blast from a structural reactive material solid

NASA Astrophysics Data System (ADS)

Zhang, F.

2018-07-01

Structural reactive material (SRM) is consolidated from a mixture of micro- or nanometric reactive metals and metal compounds to the mixture theoretical maximum density. An SRM can thus possess a higher energy density, relying on various exothermic reactions, and higher mechanical strength and heat resistance than that of conventional CHNO explosives. Progress in SRM solid studies is reviewed specifically as an energy source for air blast through the reaction of fine SRM fragments under explosive loading. This includes a baseline SRM solid explosion characterization, material properties of an SRM solid, and its dynamic fine fragmentation mechanisms and fragment reaction mechanisms. The overview is portrayed mainly from the author's own experimental studies combined with theoretical and numerical explanation. These advances have laid down some fundamentals for the next stage of developments.

Some issues for blast from a structural reactive material solid

NASA Astrophysics Data System (ADS)

Zhang, F.

2018-03-01

Structural reactive material (SRM) is consolidated from a mixture of micro- or nanometric reactive metals and metal compounds to the mixture theoretical maximum density. An SRM can thus possess a higher energy density, relying on various exothermic reactions, and higher mechanical strength and heat resistance than that of conventional CHNO explosives. Progress in SRM solid studies is reviewed specifically as an energy source for air blast through the reaction of fine SRM fragments under explosive loading. This includes a baseline SRM solid explosion characterization, material properties of an SRM solid, and its dynamic fine fragmentation mechanisms and fragment reaction mechanisms. The overview is portrayed mainly from the author's own experimental studies combined with theoretical and numerical explanation. These advances have laid down some fundamentals for the next stage of developments.

SAMPLE CHARACTERIZATION OF AUTOMOBILE AND FORKLIFT DIESEL EXHAUST PARTICLES AND COMPARATIVE PULMONARY TOXICITY IN MICE

EPA Science Inventory

Abstract

Two samples of diesel exhaust particles (DEP) predominate in DEP health effects research: an automobile-source DEP (A-DEP) sample and the National Institute of Standards Technology (NIST) standard reference material (SRM 2975) generated from a forklift engine...

Biomass-burning derived aromatic acids in NIST standard reference material 1649b and the environmental implications

NASA Astrophysics Data System (ADS)

Gao, Shaopeng; Xu, Baiqing; Dong, Xueling; Zheng, Xiaoyan; Wan, Xin; Kang, Shichang; Song, Qiuyin; Kawamura, Kimitaka; Cong, Zhiyuan

2018-07-01

Biomass burning is a serious problem in the environment and climate system. However, the source identification of biomass-burning aerosols was somewhat impeded, partly due to the difficulty in quantification of relevant molecular markers. In this study, we present reference values for five aromatic acids (including p-hydroxybenzoic, vanillic, dehydroabietic, syringic and p-coumaric acids) in the NIST Standard Reference Material (SRM) 1649b. The concentration of levoglucosan was also revisited. Notable positive matrix effect was found for vanillic, dehydroabietic, syringic and coumaric acid. Using the standard addition method, the average value of p-hydroxybenzoic, vanillic, syringic, dehydroabietic and p-coumaric acids in SRM 1649b were found to be 26.9, 9.53, 1.13, 7.60 and 1.66 μg g-1, respectively. The analytical method developed in this study was also applied to the PM10 samples from Beijing and PM2.5 samples from South Asia (Godavari, Nepal). The ratios of vanillic to p-hydroxybenzoic acid and syringic to vanillic acid further suggested that their biomass-burning types are mainly related to hard wood and herbaceous species (i.e., agricultural residues).

40 CFR Appendix A-1 to Part 50 - Reference Measurement Principle and Calibration Procedure for the Measurement of Sulfur Dioxide...

Code of Federal Regulations, 2012 CFR

2012-07-01

... to conveniently divert the SO2 from the sampling manifold to provide clean zero air at the output manifold for zero adjustment. The system may be made up using common laboratory components, or it may be a... Reference Material (SRM). 4.1.6.2Clean zero air, free of contaminants that could cause a detectable response...

40 CFR Appendix A-1 to Part 50 - Reference Measurement Principle and Calibration Procedure for the Measurement of Sulfur Dioxide...

Code of Federal Regulations, 2010 CFR

2010-07-01

... to conveniently divert the SO2 from the sampling manifold to provide clean zero air at the output manifold for zero adjustment. The system may be made up using common laboratory components, or it may be a... Reference Material (SRM). 4.1.6.2Clean zero air, free of contaminants that could cause a detectable response...

40 CFR Appendix A-1 to Part 50 - Reference Measurement Principle and Calibration Procedure for the Measurement of Sulfur Dioxide...

Code of Federal Regulations, 2014 CFR

2014-07-01

... SO2 from the sampling manifold to provide clean zero air at the output manifold for zero adjustment... Standard Reference Material (SRM). 4.1.6.2 Clean zero air, free of contaminants that could cause a... be sensitive to aromatic hydrocarbons and O2-to-N2 ratios, it is important that the clean zero air...

40 CFR Appendix A-1 to Part 50 - Reference Measurement Principle and Calibration Procedure for the Measurement of Sulfur Dioxide...

Code of Federal Regulations, 2011 CFR

2011-07-01

... to conveniently divert the SO2 from the sampling manifold to provide clean zero air at the output manifold for zero adjustment. The system may be made up using common laboratory components, or it may be a... Reference Material (SRM). 4.1.6.2Clean zero air, free of contaminants that could cause a detectable response...

40 CFR Appendix A-1 to Part 50 - Reference Measurement Principle and Calibration Procedure for the Measurement of Sulfur Dioxide...

Code of Federal Regulations, 2013 CFR

2013-07-01

... to conveniently divert the SO2 from the sampling manifold to provide clean zero air at the output manifold for zero adjustment. The system may be made up using common laboratory components, or it may be a... Reference Material (SRM). 4.1.6.2Clean zero air, free of contaminants that could cause a detectable response...

Modifications to the NIST reference measurement procedure (RMP) for the determination of serum glucose by isotope dilution gas chromatography/mass spectrometry.

PubMed

Prendergast, Jocelyn L; Sniegoski, Lorna T; Welch, Michael J; Phinney, Karen W

2010-07-01

The definitive method (DM), now known as the reference measurement procedure (RMP), for the analysis of glucose in serum was originally published in 1982 by the National Institute of Standards and Technology (NIST). Over the years the method has been subject to a number of modifications to adapt to newer technologies and simplify sample preparation. We discuss here an adaptation of the method associated with serum glucose measurements using a modified isotope dilution gas chromatography/mass spectrometry (ID-GC/MS) method. NIST has used this modified method to certify the concentrations of glucose in SRM 965b, Glucose in Frozen Human Serum, and SRM 1950, Metabolites in Human Plasma. Comparison of results from the revised method with certified values for existing Standard Reference Materials (SRMs) demonstrated that these modifications have not affected the quality of the measurements, giving both good precision and accuracy, while reducing the sample preparation time by a day and a half.

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

Lindahl, P.C.

A proposed American Society for Testing and Materials (ASTM) method for the determination of arsenic and selenium content in coal has been used and evaluated in the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) as part of an interlaboratory study. Coal is conducted with Eschka's mixture (MgO + Na/sub 2/CO/sub 3/), followed by determination of the aresnic and selenium content by hydride generation/atomic absorption spectrophotometry. The method was evaluated on a series of coals, including two National Bureau of Standards-Standards Reference Material (NBS-SRM) coals and twelve ASTM coal samples. Comparison of ACL/ANL arsenic and selenium data for themore » suite of coal analyzed showed excellent agreement with certified values for the NBS-SRM coals and with interlaboratory data from five other laboratories for the ASTM coals. 11 refs., 3 figs., 6 tabs.« less

AN EVALUATION OF SAMPLE DISPERSION MEDIAS USED WITH ACCELERATED SOLVENT EXTRACTION FOR THE EXTRACTION AND RECOVERY OF ARSENICALS FROM LFB AND DORM-2

EPA Science Inventory

An accelerated solvent extraction (ASE) device was evaluated as a semi-automated means for extracting arsenicals from quality control (QC) samples and DORM-2 [standard reference material (SRM)]. Unlike conventional extraction procedures, the ASE requires that the sample be dispe...

Determination of As, Hg and Pb in herbs using slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry.

PubMed

Tai, Chia-Yi; Jiang, Shiuh-Jen; Sahayam, A C

2016-02-01

Analysis of herbs for As, Hg and Pb has been carried out using slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) with flow injection vapor generation. Slurry containing 0.5% m/v herbal powder, 0.1% m/v citric acid and 2% v/v HCl was injected into the VG-ICP-MS system for the determination of As, Hg and Pb that obviate dissolution and mineralization. Standard addition and isotope dilution methods were used for quantifications in selected herbal powders. This method has been validated by the determination of As, Hg and Pb in NIST standard reference materials SRM 1547 Peach Leaves and SRM 1573a Tomato Leaves. The As, Hg and Pb analysis results of the reference materials agreed with the certified values. The precision obtained by the reported procedure was better than 7% for all determinations. The detection limit estimated from standard addition curve was 0.008, 0.003, and 0.007 ng mL(-1) for As, Hg and Pb, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Extraction of organic contaminants from marine sediments and tissues using microwave energy.

PubMed

Jayaraman, S; Pruell, R J; McKinney, R

2001-07-01

In this study, we compared microwave solvent extraction (MSE) to conventional methods for extracting organic contaminants from marine sediments and tissues with high and varying moisture content. The organic contaminants measured were polychlorinated biphenyl (PCB) congeners, chlorinated pesticides, and polycyclic aromatic hydrocarbons (PAHs). Initial experiments were conducted on dry standard reference materials (SRMs) and field collected marine sediments. Moisture content in samples greatly influenced the recovery of the analytes of interest. When wet sediments were included in a sample batch, low recoveries were often encountered in other samples in the batch, including the dry SRM. Experiments were conducted to test the effect of standardizing the moisture content in all samples in a batch prior to extraction. SRM1941a (marine sediment). SRM1974a (mussel tissue), as well as QA96SED6 (marine sediment), and QA96TIS7 (marine tissue), both from 1996 NIST Intercalibration Exercise were extracted using microwave and conventional methods. Moisture levels were adjusted in SRMs to match those of marine sediment and tissue samples before microwave extraction. The results demonstrated that it is crucial to standardize the moisture content in all samples, including dry reference material to ensure good recovery of organic contaminants. MSE yielded equivalent or superior recoveries compared to conventional methods for the majority of the compounds evaluated. The advantages of MSE over conventional methods are reduced solvent usage, higher sample throughput and the elimination of halogenated solvent usage.

HOW OLD IS IT? - 241PU/241AM NUCLEAR FORENSIC CHRONOLOGY REFERENCE MATERIALS

PubMed Central

Fitzgerald, Ryan; Inn, Kenneth G.W.; Horgan, Christopher

2018-01-01

One material attribute for nuclear forensics is material age. 241Pu is almost always present in uranium- and plutonium-based nuclear weapons, which pose the greatest threat to our security. The in-growth of 241Am due to the decay of 241Pu provides an excellent chronometer of the material. A well-characterized 241Pu/241Am standard is needed to validate measurement capability, as a basis for between-laboratory comparability, and as material for verifying laboratory performance. This effort verifies the certification of a 38 year old 241Pu Standard Reference Material (SRM4340) through alpha-gamma anticoincidence counting, and also establishes the separation date to two weeks of the documented date. PMID:29720779

Copper Oxide Precipitates in NBS Standard Reference Material 482

PubMed Central

Windsor, Eric S.; Carlton, Robert A.; Gillen, Greg; Wight, Scott A.; Bright, David S.

2002-01-01

Copper oxide has been detected in the copper containing alloys of NBS Standard Reference Material (SRM) 482. This occurrence is significant because it represents heterogeneity within a standard reference material that was certified to be homogeneous on a micrometer scale. Oxide occurs as elliptically to spherically shaped precipitates whose size differs with alloy composition. The largest precipitates occur in the Au20-Cu80 alloy and range in size from submicrometer up to 2 μm in diameter. Precipitates are observed using light microscopy, electron microscopy, and secondary ion mass spectrometry (SIMS). SIMS has demonstrated that the precipitates are present within all the SRM 482 wires that contain copper. Only the pure gold wire is precipitate free. Initial results from the analysis of the Au20-Cu80 alloy indicate that the percentage of precipitates is less than 1 % by area. Electron probe microanalysis (EPMA) of large (2 μm) precipitates in this same alloy indicates that precipitates are detectable by EPMA and that their composition differs significantly from the certified alloy composition. The small size and low percentage of these oxide precipitates minimizes the impact that they have upon the intended use of this standard for electron probe microanalysis. Heterogeneity caused by these oxide precipitates may however preclude the use of this standard for automated EPMA analyses and other microanalysis techniques. PMID:27446759

Heat-assisted aqueous extraction of rice flour for arsenic speciation analysis.

PubMed

Narukawa, Tomohiro; Chiba, Koichi

2010-07-28

A versatile heat-assisted pretreatment aqueous extraction method for the analysis of arsenic species in rice was developed. Rice flour certified reference materials NIST SRM1568a and NMIJ CRM 7503-a and a flour made from polished rice were used as samples, and HPLC-ICP-MS was employed for the determination of arsenic species. Arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA) were detected in NIST SRM, and As(III), As(V) and DMAA were found in NMIJ CRM and the prepared polished rice flour. The sums of the concentrations of all species in each rice flour sample were 97-102% of the total arsenic concentration in each sample.

Standard Reference Material (SRM 1990) for Single Crystal Diffractometer Alignment

USGS Publications Warehouse

Wong-Ng, W.; Siegrist, T.; DeTitta, G.T.; Finger, L.W.; Evans, H.T.; Gabe, E.J.; Enright, G.D.; Armstrong, J.T.; Levenson, M.; Cook, L.P.; Hubbard, C.R.

2001-01-01

An international project was successfully completed which involved two major undertakings: (1) a round-robin to demonstrate the viability of the selected standard and (2) the certification of the lattice parameters of the SRM 1990, a Standard Reference Material?? for single crystal diffractometer alignment. This SRM is a set of ???3500 units of Cr-doped Al2O3, or ruby spheres [(0 420.011 mole fraction % Cr (expanded uncertainty)]. The round-robin consisted of determination of lattice parameters of a pair of crystals' the ruby sphere as a standard, and a zeolite reference to serve as an unknown. Fifty pairs of crystals were dispatched from Hauptman-Woodward Medical Research Institute to volunteers in x-ray laboratories world-wide. A total of 45 sets of data was received from 32 laboratories. The mean unit cell parameters of the ruby spheres was found to be a=4.7608 A?? ?? 0.0062 A??, and c=12.9979 A?? ?? 0.020 A?? (95 % intervals of the laboratory means). The source of errors of outlier data was identified. The SRM project involved the certification of lattice parameters using four well-aligned single crystal diffractometers at (Bell Laboratories) Lucent Technologies and at NRC of Canada (39 ruby spheres), the quantification of the Cr content using a combined microprobe and SEM/EDS technique, and the evaluation of the mosaicity of the ruby spheres using a double-crystal spectrometry method. A confirmation of the lattice parameters was also conducted using a Guinier-Ha??gg camera. Systematic corrections of thermal expansion and refraction corrections were applied. These rubies_ are rhombohedral, with space group R3c. The certified mean unit cell parameters are a=4.76080 ?? 0.00029 A??, and c=12 99568 A?? ?? 0.00087 A?? (expanded uncertainty). These certified lattice parameters fall well within the results of those obtained from the international round-robin study. The Guinier-Ha??gg transmission measurements on five samples of powdered rubies (a=4.7610 A?? ?? 0.0013 A??, and c=12.9954 A?? ?? 0.0034 A??) agreed well with the values obtained from the single crystal spheres.

Standard Reference Material (SRM 1990) For Single Crystal Diffractometer Alignment

PubMed Central

Wong-Ng, W.; Siegrist, T.; DeTitta, G. T.; Finger, L. W.; Evans, H. T.; Gabe, E. J.; Enright, G. D.; Armstrong, J. T.; Levenson, M.; Cook, L. P.; Hubbard, C. R.

2001-01-01

An international project was successfully completed which involved two major undertakings: (1) a round-robin to demonstrate the viability of the selected standard and (2) the certification of the lattice parameters of the SRM 1990, a Standard Reference Material® for single crystal diffractometer alignment. This SRM is a set of ≈3500 units of Cr-doped Al2O3, or ruby spheres [(0.420.011 mole fraction % Cr (expanded uncertainty)]. The round-robin consisted of determination of lattice parameters of a pair of crystals: the ruby sphere as a standard, and a zeolite reference to serve as an unknown. Fifty pairs of crystals were dispatched from Hauptman-Woodward Medical Research Institute to volunteers in x-ray laboratories world-wide. A total of 45 sets of data was received from 32 laboratories. The mean unit cell parameters of the ruby spheres was found to be a=4.7608 ű0.0062 Å, and c=12.9979 ű0.020 Å (95 % intervals of the laboratory means). The source of errors of outlier data was identified. The SRM project involved the certification of lattice parameters using four well-aligned single crystal diffractometers at (Bell Laboratories) Lucent Technologies and at NRC of Canada (39 ruby spheres), the quantification of the Cr content using a combined microprobe and SEM/EDS technique, and the evaluation of the mosaicity of the ruby spheres using a double-crystal spectrometry method. A confirmation of the lattice parameters was also conducted using a Guinier-Hägg camera. Systematic corrections of thermal expansion and refraction corrections were applied. These rubies– are rhombohedral, with space group R3¯c. The certified mean unit cell parameters are a=4.76080±0.00029 Å, and c=12.99568 ű0.00087 Å (expanded uncertainty). These certified lattice parameters fall well within the results of those obtained from the international round-robin study. The Guinier-Hägg transmission measurements on five samples of powdered rubies (a=4.7610 ű0.0013 Å, and c = 12.9954 ű0.0034 Å) agreed well with the values obtained from the single crystal spheres. PMID:27500067

Establishment of a standard reference material (SRM) herbal DNA barcode library of Vitex negundo L. (lagundi) for quality control measures.

PubMed

Olivar, Jay Edneil C; Alaba, Joanner Paulus Erik P; Atienza, Jose Francisco M; Tan, Jerick Jeffrey S; Umali, Maximo T; Alejandro, Grecebio Jonathan D

2016-05-01

The majority of the population in the Philippines relies on herbal products as their primary source for their healthcare needs. After the recognition of Vitex negundo L. (lagundi) as an important and effective alternative medicine for cough, sore throat, asthma and fever by the Philippine Department of Health (DOH), there was an increase in the production of lagundi-based herbal products in the form of teas, capsules and syrups. The efficiency of these products is greatly reliant on the use of authentic plant material, and to this day no standard protocol has been established to authenticate plant materials. DNA barcoding offers a quick and reliable species authentication tool, but its application to plant material has been less successful due to (1) lack of a standard DNA barcoding loci in plants and (2) poor DNA yield from powderised plant products. This study reports the successful application of DNA barcoding in the authentication of five V. negundo herbal products sold in the Philippines. Also, the first standard reference material (SRM) herbal library for the recognition of authentic V. negundo samples was established using 42 gene accessions of ITS, psbA-trnH and matK barcoding loci. Authentication of the herbal products utilised the SRM following the BLASTn and maximum-likelihood (ML) tree construction criterion. Barcode sequences were retrieved for ITS and psbA-trnH of all products tested and the results of the study revealed that only one out of five herbal products satisfied both BLASTn and ML criterion and was considered to contain authentic V. negundo. The results prompt the urgent need to utilise DNA barcoding in authenticating herbal products available in the Philippine market. Authentication of these products will secure consumer health by preventing the negative effects of adulteration, substitution and contamination.

Standard reference materials: Thermal conductivity of electrolytic iron, SRM 734, from 4 to 300 K

NASA Technical Reports Server (NTRS)

Hust, J. G.; Sparks, L. L.

1971-01-01

Thermal conductivity data were obtained by the axial one-dimensional heat flow method for a cylindrical rod 3.6 mm in diameter and 23 cm long with an electric heater at one end and a temperature controlled sink at the other. Variability of this iron was studied by means of electrical residual resistivity ratio measurements on 63 specimens. This study showed that with a two-hour anneal at 1000 C one can obtain a thermal conductivity Standard Reference Material that has variability of less than 1% in thermal conductivity.

A comparative study of 129I content in environmental standard materials IAEA-375, NIST SRM 4354 and NIST SRM 4357 by Thermal Ionization Mass Spectrometry and Accelerator Mass Spectrometry.

PubMed

Olson, John; Adamic, Mary; Snyder, Darin; Brookhart, Jacob; Hahn, Paula; Watrous, Matthew

2017-08-01

Iodine environmental measurements have consistently been validated in the literature using the standard material IAEA-375, soil collected approximately 160 miles northeast of Chernobyl, which is currently the only soil/sediment material with a certified 129 I activity. IAEA-375 has not been available for purchase since approximately 2010. Two other standard materials that are available (NIST SRM 4354, freshwater lake sediment and NIST SRM 4357, ocean sediment) have certified activities for a variety of radionuclides but not for 129 I. This paper reports a comparison of TIMS and AMS data for all three standards. Copyright © 2017. Published by Elsevier Ltd.

Retrospective Analysis of NIST Standard Reference Material 1450, Fibrous Glass Board, for Thermal Insulation Measurements

PubMed Central

Zarr, Robert R; Heckert, N Alan; Leigh, Stefan D

2014-01-01

Thermal conductivity data acquired previously for the establishment of Standard Reference Material (SRM) 1450, Fibrous Glass Board, as well as subsequent renewals 1450a, 1450b, 1450c, and 1450d, are re-analyzed collectively and as individual data sets. Additional data sets for proto-1450 material lots are also included in the analysis. The data cover 36 years of activity by the National Institute of Standards and Technology (NIST) in developing and providing thermal insulation SRMs, specifically high-density molded fibrous-glass board, to the public. Collectively, the data sets cover two nominal thicknesses of 13 mm and 25 mm, bulk densities from 60 kg·m−3 to 180 kg·m−3, and mean temperatures from 100 K to 340 K. The analysis repetitively fits six models to the individual data sets. The most general form of the nested set of multilinear models used is given in the following equation: λ(ρ,T)=a0+a1ρ+a2T+a3T3+a4e−(T−a5a6)2where λ(ρ,T) is the predicted thermal conductivity (W·m−1·K−1), ρ is the bulk density (kg·m−3), T is the mean temperature (K) and ai (for i = 1, 2, … 6) are the regression coefficients. The least squares fit results for each model across all data sets are analyzed using both graphical and analytic techniques. The prevailing generic model for the majority of data sets is the bilinear model in ρ and T. λ(ρ,T)=a0+a1ρ+a2T One data set supports the inclusion of a cubic temperature term and two data sets with low-temperature data support the inclusion of an exponential term in T to improve the model predictions. Physical interpretations of the model function terms are described. Recommendations for future renewals of SRM 1450 are provided. An Addendum provides historical background on the origin of this SRM and the influence of the SRM on external measurement programs. PMID:26601034

Addressing the amorphous content issue in quantitative phase analysis : the certification of NIST SRM 676a.

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

Cline, J. P.; Von Dreele, R. B.; Winburn, R.

2011-07-01

A non-diffracting surface layer exists at any boundary of a crystal and can comprise a mass fraction of several percent in a finely divided solid. This has led to the long-standing issue of amorphous content in standards for quantitative phase analysis (QPA). NIST standard reference material (SRM) 676a is a corundum ({alpha}-Al{sub 2}O{sub 3}) powder, certified with respect to phase purity for use as an internal standard in powder diffraction QPA. The amorphous content of SRM 676a is determined by comparing diffraction data from mixtures with samples of silicon powders that were engineered to vary their specific surface area. Undermore » the (supported) assumption that the thickness of an amorphous surface layer on Si was invariant, this provided a method to control the crystalline/amorphous ratio of the silicon components of 50/50 weight mixtures of SRM 676a with silicon. Powder diffraction experiments utilizing neutron time-of-flight and 25 keV and 67 keV X-ray energies quantified the crystalline phase fractions from a series of specimens. Results from Rietveld analyses, which included a model for extinction effects in the silicon, of these data were extrapolated to the limit of zero amorphous content of the Si powder. The certified phase purity of SRM 676a is 99.02% {+-} 1.11% (95% confidence interval). This novel certification method permits quantification of amorphous content for any sample of interest, by spiking with SRM 676a.« less

Development of Rice Reprocessing to Strengthen Small Scale Rice Mills in Indramayu West Java

NASA Astrophysics Data System (ADS)

Firdaus, Y. R.; Hasbullah, R.; Djohar, S.

2018-05-01

Small Rice Mill (SRM) has a very important role in rice production of strong institutional relationships to farmers and rice markets. Nevertheless, the rice produced in low quality and changing consumer preferences cause SRM to have difficulty in maintaining the role. Development of a reprocessing business - called Rice to Rice Processing Plant (R2RP) - as a separate business unit will support their role and existence. This study aimed at analyzing the feasibility of R2RP business that integrates SRM and market as an independent business unit and determines mutual partnership pattern. The study was conducted with special reference to West Java Province. The qualitative method used for non-financial aspects analysis includes raw material, market, technical-technological, management and regulation and partnership pattern. The financial aspect used the quantitative method of Net Present Value (NPV), Net Benefit Cost Ratio (Net B/C), Internal Rate of Return (IRR), Payback Period (PP) and Switching Value to check their sensitivity.The results showed R2R business is feasible for non-financially, technical-technological and financial aspects. Technology has evolved to produce various qualities (premium or medium) after the quality of raw materials (low quality or off-grade rice) using profit optimization. Value of the financial parameters was NPV of Rp 137 billion, Net B/C of 5.80, IRR of 84.27 percent and PP of 2.18 years at capacity of 19,800 tons/year with total investment of Rp 30 billion (Rp 13,500/USD). The switching value analysis showed that a decrease in product prices is sensitively influencing the financial feasibility. To strengthen cooperation that enhancing mutually beneficial relationship, R2R assists equipment investment in and buy raw material from SRM at a rational agreed price.

Evaluation of moisture barrier coatings on carbon-phenolic SRM nozzle materials

NASA Technical Reports Server (NTRS)

Mcnutt, Ronald C.

1986-01-01

The carbon-phenolic composite ablative material used on the Solid Rocket Motor (SRM) nozzle is known to absorb moisture from the atmosphere. This could cause problems such as pocketing during firing. Several moisture barrier coatings were tested on the SRM nozzle material. Data are presented for six of the 12 coatings to be tested. The data were obtained from immersion of coated samples in an environmental chamber at 100 F and 100% relative humidity and by using a modified TGA (thermal gravimetric analysis) technique. The TGA technique involved allowing wet nitrogen (25 C, 80% relative humidity) to flow across a small sample at about 65 cu cm per minute while continually monitoring the weight increase. These preliminary results show Kel-F-800, a material supplied by 3M Corporation to be the better moisture barrier. A second task was to collect data on the relative absorption of water and kerosene into the carbon-phenolic SRM nozzle material. These data indicate that water absorbs into the nozzle material to a much greater extent than kerosene. Thus kerosene is the more likely solvent in which to make specific gravity measurements on the SRM nozzle material.

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

NASA Astrophysics Data System (ADS)

Huang, Shih-Yi; Jiang, Shiuh-Jen; Sahayam, A. C.

2014-11-01

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min- 1 methane (CH4) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g- 1 for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g- 1 (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions.

Determination of As, Cd, Hg and Pb in herbs using slurry sampling electrothermal vaporisation inductively coupled plasma mass spectrometry.

PubMed

Lin, Mei-Ling; Jiang, Shiuh-Jen

2013-12-01

Inductively coupled plasma mass spectrometry coupled with ultrasonic slurry sampling electrothermal vaporisation (USS-ETV-ICP-MS) has been applied to determine As, Cd, Hg and Pb in 0.5% m/v slurries of several herb samples. 1% m/v 8-Hydroxyquinoline was used as the modifier to enhance the ion signals. The influences of instrument operating conditions, slurry preparation and interferences on the ion signals were reported. This method has been applied to the determination of As, Cd, Hg and Pb in NIST SRM 1547 peach leaves and SRM 1573a tomato leaves reference materials and three herb samples purchased from the local market and ground to 150 μm. The analysis results of the standard reference materials agreed with the certified values which are at sub μg g(-1) levels. Precision between sample replicates was better than 4% for all the determinations. The method detection limits estimated from standard addition curves were about 0.3, 0.1, 0.1 and 0.2 ng g(-1) for As, Cd, Hg and Pb, respectively, in original herb samples. Copyright © 2013 Elsevier Ltd. All rights reserved.

An evaluation of the discriminating power of an Integrated Ballistics Identification System® Heritage™system with the NIST standard cartridge case (Standard Reference Material 2461).

PubMed

Morris, Keith B; Law, Eric F; Jefferys, Roger L; Dearth, Elizabeth C; Fabyanic, Emily B

2017-11-01

Through analysis and comparison of firing pin, breech face, and ejector impressions, where appropriate, firearm examiners may connect a cartridge case to a suspect firearm with a certain likelihood in a criminal investigation. When a firearm is not present, an examiner may use the Integrated Ballistics Identification System (IBIS ® ), an automated search and retrieval system coupled with the National Integrated Ballistics Information Network (NIBIN), a database of images showing the markings on fired cartridge cases and bullets from crime scenes along with test fired firearms. For the purpose of measurement quality control of these IBIS ® systems the National Institute of Standards and Technology (NIST) initiated the Standard Reference Material (SRM) 2460/2461 standard bullets and cartridge cases project. The aim of this study was to evaluate the overall performance of the IBIS ® system by using NIST standard cartridge cases. By evaluating the resulting correlation scores, error rates, and percent recovery, both the variability between and within examiners when using IBIS ® , in addition to any inter- and intra-variability between SRM cartridge cases was observed. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of an aerobic composting process for the management of Specified Risk Materials (SRM).

PubMed

Zeng, J; Price, G W; Arnold, P

2012-06-15

In Nova Scotia (NS), approximately 2700 tonnes of Specified Risk Materials (SRM) are produced annually. SRM disposal is a serious concern for abattoirs and the beef industry. Composting offers a low risk and simple means to transform raw SRM into a more stable and easily managed material. In this project, wheat straw and sawdust were used to compost with SRM on a pilot scale. The study evaluated changes over time in total carbon, total nitrogen, pH, temperature, moisture content and electrical conductivity. Compost temperatures in all treatments met the Canadian Council of Ministers of the Environment (CCME) guidelines for pathogen kill. The compost maturity tests showed that the evolution of CO(2)-C in all the final compost products was less than 1 mg g(-1) organic matter day(-1). Wheat straw performed well as a composting feedstock for raw SRM as sawdust. While the wheat straw has advantages including greater availability, lower cost and easily decomposable carbon compounds more management is required to maintain adequate compost temperatures. The influences of seasonal variations due to temperate climatic conditions on SRM composting were also studied with wheat straw. The results suggest no significant differences in composting effectiveness between the two seasons. Copyright © 2012 Elsevier B.V. All rights reserved.

Competitive inhibition of carcinogen-activating CYP1A1 and CYP1B1 enzymes by a standardized complex mixture of PAH extracted from coal tar

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

Mahadevan, B.; Marston, C.P.; Luch, A.

2007-03-15

A complex mixture of polycyclic aromatic hydrocarbons (PAH) extracted from coal tar, the Standard Reference Material (SRM) 1597, was recently shown to decrease the levels of DNA binding of the 2 strong carcinogens benzo(a)pyrene (BP) and dibenzo(a,l)pyrene (DBP) in the human mammary carcinoma-derived cell line MCF-7. The present study was designed to further elucidate the biochemical mechanisms involved in this inhibition process. We examined the effects of SRM 1597 on the metabolic activation of BP and DBP toward DNA-binding derivatives in Chinese hamster cells expressing either human cytochrome P450 (CYP) 1A1 or CYP1B1. The data obtained from biochemical experiments revealedmore » that SRM 1597 competitively inhibited the activity of both human enzymes as analyzed by 7-ethoxyresorufin O-deethylation assays. While the Michaelis-Menten constant (K-M) was {lt} 0.4 {mu}M in the absence of SRM 1597, this value increased up to 1.12 (CYP1A1) or 4.45 {mu}M (CYP1B1) in the presence of 0.1 {mu} g/ml SRM 1597. Hence the inhibitory effects of the complex mixture on human CYP1B1 were much stronger when compared to human CYP1A1 Taken together, the decreases in PAH-DNA adduct formation on co-treatment with SRM 1597 revealed inhibitory effects on the CYP enzymes that convert carcinogenic PAH into DNA-binding metabolites. The implications for the tumorigenicity of complex environmental PAR mixtures are discussed.« less

The Second National Ballistics Imaging Comparison (NBIC-2)

PubMed Central

Vorburger, TV; Yen, J; Song, JF; Thompson, RM; Renegar, TB; Zheng, A; Tong, M; Ols, M

2014-01-01

In response to the guidelines issued by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB-International) to establish traceability and quality assurance in U.S. crime laboratories, NIST and the ATF initiated a joint project, entitled the National Ballistics Imaging Comparison (NBIC). The NBIC project aims to establish a national traceability and quality system for ballistics identifications in crime laboratories utilizing ATF’s National Integrated Ballistics Information Network (NIBIN). The original NBIC was completed in 2010. In the second NBIC, NIST Standard Reference Material (SRM) 2461 Cartridge Cases were used as reference standards, and 14 experts from 11 U.S. crime laboratories each performed 17 image acquisitions and correlations of the SRM cartridge cases over the course of about half a year. Resulting correlation scores were collected by NIST for statistical analyses, from which control charts and control limits were developed for the proposed quality system and for promoting future assessments and accreditations for firearm evidence in U.S. forensic laboratories in accordance with the ISO 17025 Standard. PMID:26601051

The Second National Ballistics Imaging Comparison (NBIC-2).

PubMed

Vorburger, T V; Yen, J; Song, J F; Thompson, R M; Renegar, T B; Zheng, A; Tong, M; Ols, M

2014-01-01

In response to the guidelines issued by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB-International) to establish traceability and quality assurance in U.S. crime laboratories, NIST and the ATF initiated a joint project, entitled the National Ballistics Imaging Comparison (NBIC). The NBIC project aims to establish a national traceability and quality system for ballistics identifications in crime laboratories utilizing ATF's National Integrated Ballistics Information Network (NIBIN). The original NBIC was completed in 2010. In the second NBIC, NIST Standard Reference Material (SRM) 2461 Cartridge Cases were used as reference standards, and 14 experts from 11 U.S. crime laboratories each performed 17 image acquisitions and correlations of the SRM cartridge cases over the course of about half a year. Resulting correlation scores were collected by NIST for statistical analyses, from which control charts and control limits were developed for the proposed quality system and for promoting future assessments and accreditations for firearm evidence in U.S. forensic laboratories in accordance with the ISO 17025 Standard.

A candidate reference method for serum potassium measurement by inductively coupled plasma mass spectrometry.

PubMed

Yan, Ying; Han, Bingqing; Zeng, Jie; Zhou, Weiyan; Zhang, Tianjiao; Zhang, Jiangtao; Chen, Wenxiang; Zhang, Chuanbao

2017-08-28

Potassium is an important serum ion that is frequently assayed in clinical laboratories. Quality assurance requires reference methods; thus, the establishment of a candidate reference method for serum potassium measurements is important. An inductively coupled plasma mass spectrometry (ICP-MS) method was developed. Serum samples were gravimetrically spiked with an aluminum internal standard, digested with 69% ultrapure nitric acid, and diluted to the required concentration. The 39K/27Al ratios were measured by ICP-MS in hydrogen mode. The method was calibrated using 5% nitric acid matrix calibrators, and the calibration function was established using the bracketing method. The correlation coefficients between the measured 39K/27Al ratios and the analyte concentration ratios were >0.9999. The coefficients of variation were 0.40%, 0.68%, and 0.22% for the three serum samples, and the analytical recovery was 99.8%. The accuracy of the measurement was also verified by measuring certified reference materials, SRM909b and SRM956b. Comparison with the ion selective electrode routine method and international inter-laboratory comparisons gave satisfied results. The new ICP-MS method is specific, precise, simple, and low-cost, and it may be used as a candidate reference method for standardizing serum potassium measurements.

Microwave-assisted extraction and quantitative LC/ID-MS measurement of total choline and free carnitine in food standard reference materials.

PubMed

Phillips, Melissa M; Sander, Lane C

2012-01-01

The Stakeholder Panel on Infant Formula and Adult Nutritionals of AOAC INTERNATIONAL has declared both choline and carnitine to be priority nutrients in infant formulas, and ongoing efforts exist to develop or improve Official Methods of Analysis for these nutrients. As a result, matrix-based certified reference materials are needed with assigned values for these compounds. In this work, traditional acid and enzymatic hydrolysis procedures were compared to microwave-assisted acid hydrolysis, and conditions optimized to provide complete sample hydrolysis and recovery of total choline from four food standard reference materials (SRMs): whole milk powder, whole egg powder, infant formula, and soy flour. The extracts were analyzed using LC on a mixed-mode column (simultaneous RP and ion exchange) with isotope dilution-MS detection to achieve simultaneous quantification of total choline and free carnitine. Total choline has been determined in these four food matrixes with excellent precision (0.65 to 2.60%) and accuracy, as confirmed by use of SRM 1849 Infant/Adult Nutritional Formula as a control material. Free carnitine has been determined in two of these food matrixes with excellent precision (0.69 to 2.19%) and accuracy, as confirmed by use of SRM 1849 Infant/Adult Nutritional Formula as a control material. Limitations in simultaneous determination of total choline and free carnitine resulted from extreme differences in concentration of the two components in egg powder and soy flour (at least three orders of magnitude). Samples required dilution to prevent poor LC peak shape, which caused decreased precision in the determination of low concentrations of free carnitine. Despite this limitation, the described method yields results comparable to current AOAC Official Method 999.14 Choline in Infant Formula, with a decrease of more than 2 h in sample preparation time.

Alternate nozzle ablative materials program

NASA Technical Reports Server (NTRS)

Kimmel, N. A.

1984-01-01

Four subscale solid rocket motor tests were conducted successfully to evaluate alternate nozzle liner, insulation, and exit cone structural overwrap components for possible application to the Space Shuttle Solid Rocket Motor (SRM) nozzle asasembly. The 10,000 lb propellant motor tests were simulated, as close as practical, the configuration and operational environment of the full scale SRM. Fifteen PAN based and three pitch based materials had no filler in the phenolic resin, four PAN based materials had carbon microballoons in the resin, and the rest of the materials had carbon powder in the resin. Three nozzle insulation materials were evaluated; an aluminum oxide silicon oxide ceramic fiber mat phenolic material with no resin filler and two E-glass fiber mat phenolic materials with no resin filler. It was concluded by MTI/WD (the fabricator and evaluator of the test nozzles) and NASA-MSFC that it was possible to design an alternate material full scale SRM nozzle assembly, which could provide an estimated 360 lb increased payload capability for Space Shuttle launches over that obtainable with the current qualified SRM design.

Comparison of quartz standards for X-ray diffraction analysis: HSE A9950 (Sikron F600) and NIST SRM 1878.

PubMed

Chisholm, Jim

2005-06-01

A further comparison of the Health and Safety Executive (HSE) standard quartz, A9950 (Sikron F600), and the National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 1878, standard respirable alpha-quartz, has been carried out for the four principal diffraction peaks. In the earlier comparison by Jeyaratnam and Nagar (1993, Ann Occup Hyg; 37: 167-79), the standards were both treated in ways which might change the particle size distribution and therefore the proportion of crystalline quartz. The two standards have now been compared in the most direct way possible with the minimum of sample treatment. There are no significant differences in the diffraction peak positions for the two standards. Nor do the peak area intensities differ significantly. The peak height intensities are consistently and significantly higher for Sikron F600 than for NIST SRM 1878. The particle size broadening of the diffraction peaks is evidently greater for NIST 1878, whose mass median diameter is quoted as 1.6 microm against 2.6 microm for Sikron F600. Taking the certified reference value for SRM 1878 as 95.5 +/- 1.1% crystalline quartz, the HSE standard A9950 (Sikron F600) contains 96.3 +/- 1.4% crystalline quartz based on a comparison of peak area intensities. On the same basis but using peak height intensities, the nominal crystalline quartz content of A9950 (Sikron F600) is 101.2 +/- 1.8%. Results obtained by comparison of quartz standards may not be generally applicable because of the effect of sample treatment on particle size and crystalline quartz content.

Potassium Isotopic Compositions of NIST Potassium Standards and 40Ar/39Ar Mineral Standards

NASA Technical Reports Server (NTRS)

Morgan, Leah; Tappa, Mike; Ellam, Rob; Mark, Darren; Higgins, John; Simon, Justin I.

2013-01-01

Knowledge of the isotopic ratios of standards, spikes, and reference materials is fundamental to the accuracy of many geochronological methods. For example, the 238U/235U ratio relevant to U-Pb geochronology was recently re-determined [1] and shown to differ significantly from the previously accepted value employed during age determinations. These underlying values are fundamental to accurate age calculations in many isotopic systems, and uncertainty in these values can represent a significant (and often unrecognized) portion of the uncertainty budget for determined ages. The potassium isotopic composition of mineral standards, or neutron flux monitors, is a critical, but often overlooked component in the calculation of K-Ar and 40Ar/39Ar ages. It is currently assumed that all terrestrial materials have abundances indistinguishable from that of NIST SRM 985 [2]; this is apparently a reasonable assumption at the 0.25per mille level (1s) [3]. The 40Ar/39Ar method further relies on the assumption that standards and samples (including primary and secondary standards) have indistinguishable 40K/39K values. We will present data establishing the potassium isotopic compositions of NIST isotopic K SRM 985, elemental K SRM 999b, and 40Ar/39Ar biotite mineral standard GA1550 (sample MD-2). Stable isotopic compositions (41K/39K) were measured by the peak shoulder method with high resolution MC-ICP-MS (Thermo Scientific NEPTUNE Plus), using the accepted value of NIST isotopic SRM 985 [2] for fractionation [4] corrections [5]. 40K abundances were measured by TIMS (Thermo Scientific TRITON), using 41K/39K values from ICP-MS measurements (or, for SRM 985, values from [2]) for internal fractionation corrections. Collectively these data represent an important step towards a metrologically traceable calibration of 40K concentrations in primary 40Ar/39Ar mineral standards and improve uncertainties by ca. an order of magnitude in the potassium isotopic compositions of standards.

40 CFR Appendix C to Part 136 - Determination of Metals and Trace Elements in Water and Wastes by Inductively Coupled Plasma...

Code of Federal Regulations, 2014 CFR

2014-07-01

... comparative data to other methods and SRM materials are presented in Reference 23 of Section 16.0. 13... Plasma, Anal. Chem. 52:1965, 1980. 20. Deming, S.N. and S.L. Morgan. Experimental Design for Quality and... Statistical Designs, 9941 Rowlett, Suite 6, Houston, TX 77075, 1989. 21. Winefordner, J.D., Trace Analysis...

40 CFR Appendix C to Part 136 - Determination of Metals and Trace Elements in Water and Wastes by Inductively Coupled Plasma...

Code of Federal Regulations, 2013 CFR

2013-07-01

... comparative data to other methods and SRM materials are presented in Reference 23 of Section 16.0. 13... Plasma, Anal. Chem. 52:1965, 1980. 20. Deming, S.N. and S.L. Morgan. Experimental Design for Quality and... Statistical Designs, 9941 Rowlett, Suite 6, Houston, TX 77075, 1989. 21. Winefordner, J.D., Trace Analysis...

40 CFR Appendix C to Part 136 - Determination of Metals and Trace Elements in Water and Wastes by Inductively Coupled Plasma...

Code of Federal Regulations, 2012 CFR

2012-07-01

... comparative data to other methods and SRM materials are presented in Reference 23 of Section 16.0. 13... Plasma, Anal. Chem. 52:1965, 1980. 20. Deming, S.N. and S.L. Morgan. Experimental Design for Quality and... Statistical Designs, 9941 Rowlett, Suite 6, Houston, TX 77075, 1989. 21. Winefordner, J.D., Trace Analysis...

Interlaboratory Comparison of Magnetic Thin Film Measurements.

PubMed

da Silva, F C S; Wang, C M; Pappas, D P

2003-01-01

A potential low magnetic moment standard reference material (SRM) was studied in an interlaboratory comparison. The mean and the standard deviation of the saturation moment m s, the remanent moment m r, and the intrinsic coercivity H c of nine samples were extracted from hysteresis-loop measurements. Samples were measured by thirteen laboratories using inductive-field loopers, vibrating-sample magnetometers, alternating-gradient force magnetometers, and superconducting quantum-interference-device magnetometers. NiFe films on Si substrates had saturation moment measurements reproduced within 5 % variation among the laboratories. The results show that a good candidate for an SRM must have a highly square hysteresis loop (m r/m s > 90 %), H c ≈ 400 A·m(-1) (5 Oe), and m s ≈ 2 × 10(-7) A·m(2) (2 × 10(-4) emu).

Reference measurement procedure for total glycerides by isotope dilution GC-MS.

PubMed

Edwards, Selvin H; Stribling, Shelton L; Pyatt, Susan D; Kimberly, Mary M

2012-04-01

The CDC's Lipid Standardization Program established the chromotropic acid (CA) reference measurement procedure (RMP) as the accuracy base for standardization and metrological traceability for triglyceride testing. The CA RMP has several disadvantages, including lack of ruggedness. It uses obsolete instrumentation and hazardous reagents. To overcome these problems the CDC developed an isotope dilution GC-MS (ID-GC-MS) RMP for total glycerides in serum. We diluted serum samples with Tris-HCl buffer solution and spiked 200-μL aliquots with [(13)C(3)]-glycerol. These samples were incubated and hydrolyzed under basic conditions. The samples were dried, derivatized with acetic anhydride and pyridine, extracted with ethyl acetate, and analyzed by ID-GC-MS. Linearity, imprecision, and accuracy were evaluated by analyzing calibrator solutions, 10 serum pools, and a standard reference material (SRM 1951b). The calibration response was linear for the range of calibrator concentrations examined (0-1.24 mmol/L) with a slope and intercept of 0.717 (95% CI, 0.7123-0.7225) and 0.3122 (95% CI, 0.3096-0.3140), respectively. The limit of detection was 14.8 μmol/L. The mean %CV for the sample set (serum pools and SRM) was 1.2%. The mean %bias from NIST isotope dilution MS values for SRM 1951b was 0.7%. This ID-GC-MS RMP has the specificity and ruggedness to accurately quantify total glycerides in the serum pools used in the CDC's Lipid Standardization Program and demonstrates sufficiently acceptable agreement with the NIST primary RMP for total glyceride measurement.

Development of a NIST standard reference material containing thirty volatile organic compounds at 5 nmol/mol in nitrogen.

PubMed

Rhoderick, George C; Yen, James H

2006-05-01

Primary gravimetric gas cylinder standards containing 30 volatile organic compounds (VOCs) in nitrogen were prepared using a procedure previously developed to prepare gas mixture cylinder standards of VOCs at the 5 nmol/mol level. This set of primary standards was intercompared to existing gas cylinder standards, containing as many as 19 of the 30 volatile organics present in these new primaries, using gas chromatography with a hydrogen flame ionization detector coupled with cryogenic preconcentration. The linear regression analysis showed excellent agreement among the standards for each compound. Similar mixtures containing many of these compounds in treated aluminum gas cylinders have been evaluated over time and have shown stability for as much as 10 years. The development of these 30-component primary standards led to the preparation and certification of a reissue of Standard Reference Material (SRM) 1804 at the nominal amount-of-substance fraction of 5 nmol/mol for each analyte. A lot of 20 cylinders containing the mixture was prepared at NIST following previously demonstrated protocols for preparation of the cylinders. Each cylinder was analyzed against one cylinder from the lot, designated as the "lot standard," for each of the 30 compounds. As a result of the uncertainty analysis, the data showed that rather than declaring the lot homogeneous with a much higher uncertainty, each cylinder could be individually certified. The expanded uncertainty limits ranged from 1.5 to 10% for 28 of the 30 analytes, with two of the analytes having uncertainties as high as 19% in those SRM cylinders certified. Due to stability issues and some high uncertainties for a few analytes in 2 of the samples, 18 of the 20 candidate SRM samples were certified. These volatile organic gas mixtures represent the most complex gas SRMs developed at NIST.

Development of a Northern Continental Air Standard Reference Material.

PubMed

Rhoderick, George C; Kitzis, Duane R; Kelley, Michael E; Miller, Walter R; Hall, Bradley D; Dlugokencky, Edward J; Tans, Pieter P; Possolo, Antonio; Carney, Jennifer

2016-03-15

The National Institute of Standards and Technology (NIST) recently began to develop standard mixtures of greenhouse gases as part of a broad program mandated by the 2009 United States Congress to support research in climate change. To this end, NIST developed suites of gravimetrically assigned primary standard mixtures (PSMs) comprising carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in a dry-natural air balance at ambient mole fraction levels. In parallel, the National Oceanic and Atmospheric Administration (NOAA) in Boulder, Colorado, charged 30 aluminum gas cylinders with northern hemisphere air at Niwot Ridge, Colorado. These mixtures, which constitute NIST Standard Reference Material (SRM) 1720 Northern Continental Air, were certified by NIST for ambient mole fractions of CO2, CH4, and N2O relative to NIST PSMs. NOAA-assigned values are also provided as information in support of the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Program for CO2, CH4, and N2O, since NOAA serves as the WMO Central Calibration Laboratory (CCL) for CO2, CH4, and N2O. Relative expanded uncertainties at the 95% confidence interval are <±0.06% of the certified values for CO2 and N2O and <0.2% for CH4, which represents the smallest relative uncertainties specified to date for a gaseous SRM produced by NIST. Agreement between the NOAA (WMO/GAW) and NIST values based on their respective calibration standards suites is within 0.05%, 0.13%, and 0.06% for CO2, CH4, and N2O, respectively. This collaborative development effort also represents the first of its kind for a gaseous SRM developed by NIST.

Reference measurement procedure for the determination of electrolytes in human blood via ICP-OES measurement

NASA Astrophysics Data System (ADS)

Grote-Koska, D.; Klauke, R.; Brand, K.; Schumann, G.

2018-04-01

The determination of electrolytes in human body fluids is one of the most frequently performed analyses in clinical routine laboratories. Metrological traceability of measurement results in patient samples is essential and requires the involvement of higher order reference measurement procedures wherever available. Here, the authors present the evaluation of a higher order reference system for the simultaneous determination of K+, Li+, Na+, Ca2+ and Mg2+ in blood serum and plasma. In the same order, the determined measurement performances were as follows: measurement ranges: 0.75 mmol l-1-75.0 mmol l-1, 0.05 mmol l-1-5.00 mmol l-1, 5 mmol l-1-200 mmol l-1, 0.4 mmol l-1-8.0 mmol l-1 and 0.1 mmol l-1-4.0 mmol l-1. Measurement imprecision: CVs were  ⩽1.1% for intra assay investigations and  ⩽1.8% for long term inter assay investigations for all measurands. Excellent accuracy was found testing certified Standard Reference Materials from NIST: SRM 909 (deviations from 0.0% to 1.1%) and SRM 956 (deviations from 0.0% to 1.5%). Intercomparisons with the German Metrology Institute (PTB) revealed differences from 0.1% to 0.8%. Matrix influences and carry over were not detectable. The expanded combined measurement uncertainties for the determination of the reference method values were estimated as  ⩾1.5% (k  =  2) for each measurand. The reference measurement procedure is accredited by the German accreditation body (DAkkS) in association with the German calibration service (DKD) according to ISO 17025 and ISO 15195. Services comprise the certification of calibrators, control materials and samples used in proficiency testing schemes.

Hubble Space Telescope: SRM/QA observations and lessons learned

NASA Technical Reports Server (NTRS)

Rodney, George A.

1990-01-01

The Hubble Space Telescope (HST) Optical Systems Board of Investigation was established on July 2, 1990 to review, analyze, and evaluate the facts and circumstances regarding the manufacture, development, and testing of the HST Optical Telescope Assembly (OTA). Specifically, the board was tasked to ascertain what caused the spherical aberration and how it escaped notice until on-orbit operation. The error that caused the on-orbit spherical aberration in the primary mirror was traced to the assembly process of the Reflective Null Corrector, one of the three Null Correctors developed as special test equipment (STE) to measure and test the primary mirror. Therefore, the safety, reliability, maintainability, and quality assurance (SRM&QA) investigation covers the events and the overall product assurance environment during the manufacturing phase of the primary mirror and Null Correctors (from 1978 through 1981). The SRM&QA issues that were identified during the HST investigation are summarized. The crucial product assurance requirements (including nonconformance processing) for the HST are examined. The history of Quality Assurance (QA) practices at Perkin-Elmer (P-E) for the period under investigation are reviewed. The importance of the information management function is discussed relative to data retention/control issues. Metrology and other critical technical issues also are discussed. The SRM&QA lessons learned from the investigation are presented along with specific recommendations. Appendix A provides the MSFC SRM&QA report. Appendix B provides supplemental reference materials. Appendix C presents the findings of the independent optical consultants, Optical Research Associates (ORA). Appendix D provides further details of the fault-tree analysis portion of the investigation process.

Bromine isotope ratio measurements in seawater by multi-collector inductively coupled plasma-mass spectrometry with a conventional sample introduction system.

PubMed

de Gois, Jefferson S; Vallelonga, Paul; Spolaor, Andrea; Devulder, Veerle; Borges, Daniel L G; Vanhaecke, Frank

2016-01-01

A simple and accurate methodology for Br isotope ratio measurements in seawater by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) with pneumatic nebulization for sample introduction was developed. The Br(+) signals could be measured interference-free at high mass resolution. Memory effects for Br were counteracted using 5 mmol L(-1) of NH4OH in sample, standard, and wash solutions. The major cation load of seawater was removed via cation exchange chromatography using Dowex 50WX8 resin. Subsequent Br preconcentration was accomplished via evaporation of the sample solution at 90 °C, which did not induce Br losses or isotope fractionation. Mass discrimination was corrected for by external correction using a Cl-matched standard measured in a sample-standard bracketing approach, although Sr, Ge, and Se were also tested as potential internal standards for internal correction for mass discrimination. The δ(81)Br (versus standard mean ocean bromide (SMOB)) values thus obtained for the NaBr isotopic reference material NIST SRM 977 and for IRMM BCR-403 seawater certified reference material are in agreement with literature values. For NIST SRM 977, the (81)Br/(79)Br ratio (0.97291) was determined with a precision ≤0.08‰ relative standard deviation (RSD).

Statistical Analysis of a Round-Robin Measurement Survey of Two Candidate Materials for a Seebeck Coefficient Standard Reference Material

PubMed Central

Lu, Z. Q. J.; Lowhorn, N. D.; Wong-Ng, W.; Zhang, W.; Thomas, E. L.; Otani, M.; Green, M. L.; Tran, T. N.; Caylor, C.; Dilley, N. R.; Downey, A.; Edwards, B.; Elsner, N.; Ghamaty, S.; Hogan, T.; Jie, Q.; Li, Q.; Martin, J.; Nolas, G.; Obara, H.; Sharp, J.; Venkatasubramanian, R.; Willigan, R.; Yang, J.; Tritt, T.

2009-01-01

In an effort to develop a Standard Reference Material (SRM™) for Seebeck coefficient, we have conducted a round-robin measurement survey of two candidate materials—undoped Bi2Te3 and Constantan (55 % Cu and 45 % Ni alloy). Measurements were performed in two rounds by twelve laboratories involved in active thermoelectric research using a number of different commercial and custom-built measurement systems and techniques. In this paper we report the detailed statistical analyses on the interlaboratory measurement results and the statistical methodology for analysis of irregularly sampled measurement curves in the interlaboratory study setting. Based on these results, we have selected Bi2Te3 as the prototype standard material. Once available, this SRM will be useful for future interlaboratory data comparison and instrument calibrations. PMID:27504212

Airborne polycyclic aromatic hydrocarbons trigger human skin cells aging through aryl hydrocarbon receptor.

PubMed

Qiao, Yuan; Li, Qiang; Du, Hong-Yang; Wang, Qiao-Wei; Huang, Ye; Liu, Wei

2017-07-01

Accumulating evidence suggests that polycyclic aromatic hydrocarbons (PAH) which adsorbed on the surface of ambient air particulate matters (PM), are the major toxic compound to cause cardiovascular and respiratory diseases, even cancer. However, its detrimental effects on human skin cell remain unclear. Here, we demonstrated that SRM1649b, a reference urban dust material of PAH, triggers human skin cells aging through cell cycle arrest, cell growth inhibition and apoptosis. Principally, SRM1649b facilitated Aryl hydrocarbon receptor (AhR) translocated into nucleus, subsequently activated ERK/MAPK signaling pathway, and upregulated aging-related genes expression. Most important, we found that AhR antagonist efficiently revert the aging of skin cells. Thus our novel findings firstly revealed the mechanism of skin aging under PAH contamination and provided potential strategy for clinical application. Copyright © 2017. Published by Elsevier Inc.

cSRM 2035: a rare-earth oxide glass for the wavelength calibration of near-infrared dispersive and Fourier transform spectrometers

NASA Astrophysics Data System (ADS)

Choquette, Steven J.; Travis, John C.; Duewer, David L.

1998-10-01

The National Institute of Standards and Technology is developing an optical filter standard for calibration of the wavelength axis of near infrared (NIR) transmission spectrometers. A design goal for the initial candidate Standard Reference Material (cSRM) filter was to provide absorbance peaks evenly covering the spectral region between 800 nm to 1600 mm (12,000 cm-1 to 6,500 cm-1). The reproducibility of the peak location, for batch-certified filters, was to be better than 0.02 nm (approximately 0.1 cm-1). Glasses with 1 to 3 mole % Yb2O3, Sm2O3, and Nd2O3, incorporated into a commercial lanthanum oxide glass were evaluated for this proposed optical standard. An initial batch of cSRM 2035 filters was prepared based on studies of glasses made and evaluated in our laboratory. An interlaboratory comparison study was initiated in February 1997 to evaluate the utility of these filters for the chemical, pharmaceutical, instrumentation, and regulatory communities. Information concerning peak-picking algorithms, wavelength coverage, geometry preferences, and other parameters was solicited from the users. Based upon input from the participants of this interlaboratory study, we are making several changes to make SRM 2035 more useful to our customers. Two of these changes are: (1) incorporating Ho2O3 into the glass to introduce an absorbance peak at approximately 2000 nm (approximately 5000 cm-1) and (2) providing users with a standard center of gravity (COG) peak-picking algorithm to locate the absorbance peaks of the SRM filter precisely. Recent results have demonstrated that the COG method provides a 10 fold improvement in the precision of locating peaks compared with traditional peak-picking methods.

Discrimination of Biological and Chemical Threat Simulants in Residue Mixtures on Multiple Substrates

DTIC Science & Technology

2011-02-18

environmental interferents selected for this study included dolomitic limestone (Lime, NIST Standard Reference Materials, Catalog No. SRM 88b) and ovalbumin...emission lines due solely to substrates or interferents can be ignored. As in previous studies by our group, the background-corrected peak ...calculated by adding the intensi- ties of the emission lines at 486 and 656 nm); the summed intensities were normalized to the total peak intensity of the

Influence of chemical straightening on the stability of drugs of abuse in hair.

PubMed

Pritchett, Jeanita S; Phinney, Karen W

2015-01-01

Chemical straightening, also known as a relaxer, is ubiquitously used among African American women to obtain straighter hair compared with their natural tresses. This study focused on the stability of drugs of abuse in hair after a single application of the relaxer. Commercially available 'Lye' or 'No-Lye' chemical straightening products (Silk Elements™) were applied in vitro to drug-fortified hair (standard reference materials (SRM) 2379 and 2380) and hairs clipped from established drug users. Target analytes (cocaine (COC), benzoylecgonine (BZE), cocaethylene (CE), phencyclidine and tetrahydrocannabinol) were isolated using solid-phase extraction and then analyzed with isotope dilution gas chromatography-mass spectrometry with selective ion monitoring. After either treatment, drug concentrations were significantly (P < 0.05) decreased in both the SRM sample and the hair from authentic abusers. In the SRM groups, 6-67% of the original concentration remained after a single chemical treatment. Similarly, only 5-30% of the original concentration remained in authentic drug hairs that had formerly tested positive for COC, BZE and CE. Published by Oxford University Press 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.

ALT-114 and ALT-118 Alternative Approaches to NIST ...

EPA Pesticide Factsheets

In 2016, US EPA approved two separate alternatives (ALT 114 and ALT 118) for the preparation and certification of Hydrogen Chloride (HCl) and Mercury (Hg) cylinder reference gas standards that can serve as EPA Protocol gases where EPA Protocol are required, but unavailable. The alternatives were necessary due to the unavailability of NIST reference materials (SRM, NTRM, CRM or RGM) or VSL reference materials (VSL PRM or VSL CRM), reference materials identified in EPA’s Green Book as necessary to establish the traceability of EPA protocol gases. ALT 114 and ALT 118 provides a pathway for gas vendors to prepare and certify traceable gas cylinder standards for use in certifying Hg and HCl CEMS. In this presentation, EPA will describe the mechanics and requirements of the performance-based approach, provide an update on the availability of these gas standards and also discuss the potential for producing and certifying gas standards for other compounds using this approach. This presentation discusses the importance of NIST-traceable reference gases relative to regulatory source compliance emissions monitoring. Specifically this presentation discusses 2 new approaches for making necessary reference gases available in the absence of NIST reference materials. Moreover, these approaches provide an alternative approach to rapidly make available new reference gases for additional HAPS regulatory compliance emissions measurement and monitoring.

Isotopic Analysis of Uranium in NIST SRM Glass by Femtosecond Laser Ablation

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

Duffin, Andrew M.; Hart, Garret L.; Hanlen, Richard C.

We employed femtosecond Laser Ablation Multicollector Inductively Coupled Mass Spectrometry for the 11 determination of uranium isotope ratios in a series of standard reference material glasses (NIST 610, 612, 614, and 12 616). This uranium concentration in this series of SRM glasses is a combination of isotopically natural uranium in 13 the materials used to make the glass matrix and isotopically depleted uranium added to increase the uranium 14 elemental concentration across the series. Results for NIST 610 are in excellent agreement with literature values. 15 However, other than atom percent 235U, little information is available for the remaining glasses.more » We present atom 16 percent and isotope ratios for 234U, 235U, 236U, and 238U for all four glasses. Our results show deviations from the 17 certificate values for the atom percent 235U, indicating the need for further examination of the uranium isotopes in 18 NIST 610-616. Our results are fully consistent with a two isotopic component mixing between the depleted 19 uranium spike and natural uranium in the bulk glass.« less

An approach for identification and determination of arsenic species in the extract of kelp.

PubMed

Yu, Lee L; Wei, Chao; Zeisler, Rolf; Tong, Junting; Oflaz, Rabia; Bao, Haixia; Wang, Jun

2015-05-01

The National Institute of Standards and Technology is developing a kelp powder standard reference material (SRM) in support of dietary supplement measurements. Edible seaweeds such as kelp and laver consumed as diet or dietary supplement contain tens of mg/kg arsenic. The speciation information of arsenic in the seaweed should be provided because the total arsenic alone does not fully address the safety issue of the dietary supplement as the value assignment is originally intended. The inability to avail all arsenic species for value assignment measurements prevented the certification of arsenic species in the candidate SRM; however, approximately 70 % of total arsenic extracted with a 1:1 volume fraction of methanol:water mixture allowed arsenic speciation values to be assigned to a procedure-defined extract, which may be used for method validation in research to improve upon current extraction and measurement practices. Arsenic species in kelp and laver were identified using electrospray ionization ion trap time of flight mass spectrometry (ESI-IT-TOF). Arsenosugars As(328), As(482), and As(392) were found in the kelp candidate SRM while As(328) and As(482) were found in GBW 08521, a certified reference material (CRM) of laver produced by the National Institute of Metrology of China (NIM). A discovery that the digests of kelp and laver contained only dimethylarsinic acid led to the conclusion that the seaweeds did not contain detectible levels of arsenobetaine, arsenocholine or trimethylarsine oxide that could overlap with the peaks of arsenosugars in the separation. The mean ± s of (5.68 ± 0.28) mg/kg and (13.43 ± 0.31) mg/kg found for As(482) and As(392) in kelp, respectively, using instrumental neutron activation analysis (INAA) demonstrated that value assignment measurement of arsenosugars was possible without arsenosugar calibration standards.

SMART GROUND Project: SMART data collection and inteGRation platform to enhance availability and accessibility of data and infOrmation in the EU territory on SecoNDary Raw Materials

NASA Astrophysics Data System (ADS)

Rossetti, Piergiorgio; Antonella Dino, Giovanna; de la Feld, Marco; Pizza, Antonietta; Coulon, Frederic; Wagland, Stuart; Gomes, Diogo

2016-04-01

The issue of resource security has come to the forefront of the debate over recent years, partly due to considerable concern over the security of supply of the so called 'critical' materials, with rare earths attracting the greatest attention in the press. Their supply is fundamental to maintain and develop EU economy and its industries relied on a steady supply of Raw Materials. Thus considering the increasing scarcity and raising prices of both, energy raw materials and other raw materials, such as metals and minerals, the recycling and recovery of these materials from anthropogenic deposits such as landfills is of increasing relevance. Europe has somewhere between 150,000 and 500,000 landfill sites, with an estimated 90% of them being "non-sanitary" pre-dating the EU Landfill Directive of 1999. Thus historical background makes the numerous old waste dumps as possible sources of critical and secondary raw materials (SRM and CRM). However, to date there is no inventory available of SRM and CRM present in EU landfills, and best management practices to recover SRM from landfill activities are inefficient. In this context, the EU SMART GROUND (SG) project (Grant Agreement No 641988) intends to foster resource recovery in landfills by improving both the availability and the accessibility of data and information on SRM in the EU and creating synergies among the different stakeholders involved in the SRM value chain. To do so, the project aims to collect and integrate in a single EU databank (SMART GROUND Data Bank) all the data from existing databases and new information retrieved during project activities. Such data will be collected from the different waste streams including municipal, industrial and mining wastes across EU landfills. It will improve data gathering on SRM from different types of waste, by defining new and integrated data acquisition methods and standards. At last, but not least, the project will also improve the SRM economic and employment potential, by i) providing training on the assessment of landfill sites material recovery to targeting end-users, ii) establishing a dedicated network of academic, industrial, regulators and other stakeholders committed to cost-effective research, technology transfer and training. The present contribution will provide an overview of the SMART GROUND project and highlights the results obtained during the first six months of project activity.

Mouse assay for determination of arsenic bioavailability in contaminated soils.

PubMed

Bradham, Karen D; Diamond, Gary L; Scheckel, Kirk G; Hughes, Michael F; Casteel, Stan W; Miller, Bradley W; Klotzbach, Julie M; Thayer, William C; Thomas, David J

2013-01-01

A mouse assay for measuring the relative bioavailability (RBA) of arsenic (As) in soil was developed. In this study, results are presented of RBA assays of 16 soils, including multiple assays of the same soils, which provide a quantitative assessment of reproducibility of mouse assay results, as well as a comparison of results from the mouse assay with results from a swine and monkey assay applied to the same test soils. The mouse assay is highly reproducible; three repeated assays on the same soils yielded RBA estimates that ranged from 1 to 3% of the group mean. The mouse, monkey, and swine models yielded similar results for some, but not all, test materials. RBA estimates for identical soils (nine test soils and three standard reference materials [SRM]) assayed in mice and swine were significantly correlated (r = 0.70). Swine RBA estimates for 6 of the 12 test materials were higher than those from the mouse assay. RBA estimates for three standard reference materials (SRM) were not statistically different (mouse/swine ratio ranged from 0.86-1). When four test soils from the same orchard were assessed in the mouse, monkey, and swine assays, the mean soil As RBA were not statistically different. Mouse and swine models predicted similar steady state urinary excretion fractions (UEF) for As of 62 and 74%, respectively, during repeated ingestion doses of sodium arsenate, the water-soluble As form used as the reference in the calculation of RBA. In the mouse assay, the UEF for water soluble As(V) (sodium arsenate) and As(III) (sodium [meta] arsenite) were 62% and 66%, respectively, suggesting similar absolute bioavailabilities for the two As species. The mouse assay can serve as a highly cost-effective alternative or supplement to monkey and swine assays for improving As risk assessments by providing site-specific assessments of RBA of As in soils.

Statistical Analysis of Firearms/Toolmarks Interpretation of Cartridge Case Evidence Using IBIS and Bayesian Networks

DTIC Science & Technology

2015-10-24

reference material (SRM) was entered into IBIS 10 times by each of three users (EBF, RLJ, and EFL). Each of these users has more than 12 months...bullet leaves the muzzle. In a recoil action (locked breech) pistol, the barrel and slide are securely locked together at the moment of firing. They...travel backward together until the barrel unlocks, forced down by a link or inclined plane, and continues rearward under its own momentum. A

The use of a single multielement standard for trace analysis in biological materials by external beam PIXE

NASA Astrophysics Data System (ADS)

Biswas, S. K.; Khaliquzzaman, M.; Islam, M. M.; Khan, A. H.

1984-04-01

The validity of the use of a single multielement standard for mass calibration in thick-target external beam PIXE analysis of biological materials has been investigated. In this study, the NBS orchard leaf, SRM 1571, was used as the basic standard for trace element analysis in other biological materials. Using the present procedure, the concentrations of K, Ca, Mn, Fe, Ni, Cu, Zn, Br, Rb and Sr were determined in several NBS reference materials such as bovine liver, spinach, rice flour, etc., generally in 20 μC irradiations with 2.0 MeV protons. The analytical results are compared with certified values of the NBS as well as with other measurements and the sources of errors are discussed.

Bimetallic Nanocatalysts in Mesoporous Silica for Hydrogen Production from Coal-Derived Fuels

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

Kuila, Debasish; Ilias, Shamsuddin

2013-02-13

In steam reforming reactions (SRRs) of alkanes and alcohols to produce H 2, noble metals such as platinum (Pt) and palladium (Pd) are extensively used as catalyst. These metals are expensive; so, to reduce noble-metal loading, bi-metallic nanocatalysts containing non-noble metals in MCM-41 (Mobil Composition of Material No. 41, a mesoporous material) as a support material with high-surface area were synthesized using one-pot hydrothermal procedure with a surfactant such as cetyltrimethylammonium bromide (CTAB) as a template. Bi-metallic nanocatalysts of Pd-Ni and Pd-Co with varying metal loadings in MCM-41 were characterized by x-ray diffraction (XRD), N 2 adsorption, and Transmission electronmore » microscopy (TEM) techniques. The BET surface area of MCM-41 (~1000 m 2/g) containing metal nanoparticles decreases with the increase in metal loading. The FTIR studies confirm strong interaction between Si-O-M (M = Pd, Ni, Co) units and successful inclusion of metal into the mesoporous silica matrix. The catalyst activities were examined in steam reforming of methanol (SRM) reactions to produce hydrogen. Reference tests using catalysts containing individual metals (Pd, Ni and Co) were also performed to investigate the effect of the bimetallic system on the catalytic behavior in the SRM reactions. The bimetallic system remarkably improves the hydrogen selectivity, methanol conversion and stability of the catalyst. The results are consistent with a synergistic behavior for the Pd-Ni-bimetallic system. The performance, durability and thermal stability of the Pd-Ni/MCM-41 and Pd-Co/MCM-41 suggest that these materials may be promising catalysts for hydrogen production from biofuels. A part of this work for synthesis and characterization of Pd-Ni-MCM-41 and its activity for SRM reactions has been published (“Development of Mesoporous Silica Encapsulated Pd-Ni Nanocatalyst for Hydrogen Production” in “Production and Purification of Ultraclean Transportation Fuels”; Hu, Y., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.)« less

Evaluation of a tunable bandpass reaction cell inductively coupled plasma mass spectrometer for the determination of selenium in serum and urine

NASA Astrophysics Data System (ADS)

Nixon, David E.; Neubauer, Kenneth R.; Eckdahl, Steven J.; Butz, John A.; Burritt, Mary F.

2003-01-01

A Dynamic Reaction Cell™ inductively coupled plasma mass spectrometer (DRC-ICP-MS) was evaluated for the determination of selenium in serum and urine. Reaction cell conditions were evaluated for the suppression of Ar 2+ dimer at m/ z 78 and 80 using methane as the reaction gas. A diluent containing 10% ethanol, 1% nitric acid, 0.5% Triton X-100 with gallium and yttrium internal standards was used to dilute urine and serum samples. Instrument response calibration was achieved by using aqueous acidic standards spiked into a urine matrix. Slopes for aqueous inorganic selenium, seleno- DL-cystine, seleno- DL-methionine and trimethylselenonium iodide spiked into urine and serum matrices were nearly identical. In general, reagent blank readings and detection limits were significantly lower in the DRC mode (reaction cell pressurized) than the standard mode (cell vented). Average results for the analysis of National Institute of Standards and Technology Standard Reference Material (NIST SRM) 1598 bovine serum (attained over 13 days) are: 43.8±3.6 μg Se/l. Reference concentration is 43.6±3.6 μg Se/l. For NIST SRM 2670 Normal Urine the DRC-ICP-MS results are 30.7±4.6 μg Se/l with a certified concentration of 30±8 μg Se/l. For NIST SRM 2670 Elevated Urine the DRC-ICP-MS results are 463±35 μg Se/l with a certified concentration of 460±30 μg Se/l. The DRC-ICP-MS results for selenium determinations in urine and serum survey samples from the Institut National de Sante Publique du Quebec were compared with the reference concentrations and results produced by conventional ICP-MS. While conventional ICP-MS gave acceptable results for survey samples, DRC-ICP-MS gave excellent results for both urine and sera. Closer correlation was observed for DRC-ICP-MS results with target concentrations than with conventional ICP-MS.

Thermostructural responses of carbon phenolics in a restrained thermal growth test

NASA Technical Reports Server (NTRS)

Wang, C. Jeff

1992-01-01

The thermostructural response of carbon phenolic components in a solid rocket motor (SRM) is a complex process. It involves simultaneous heat and mass transfer along with chemical reactions in a multiphase system with time-dependent material properties and boundary conditions. In contrast to metals, the fracture of fiber-reinforced composites is characterized by the initiation and progression of multiple failures of different modes such as matrix cracks, interfacial debonding, fiber breaks, and delamination. The investigation of thermostructural responses of SRM carbon phenolics is further complicated by different failure modes under static and dynamic load applications. Historically, there have been several types of post-firing anomalies found in the carbon phenolic composites of the Space Shuttle SRM nozzle. Three major failure modes which have been observed on SRM nozzles are pocketing (spallation), ply-lift, and wedge-out. In order to efficiently control these anomalous phenomena, an investigation of fracture mechanisms under NASA/MSFC RSRM (Redesigned Solid Rocket Motor) and SPIP (Solid Propulsion Integrity Program) programs have been conducted following each anomaly. This report reviews the current progress in understanding the effects of the thermostructural behavior of carbon phenolics on the failure mechanisms of the SRM nozzle. A literature search was conducted and a technical bibliography was developed to support consolidation and assimilation of learning from the RSRM and SPIP investigation efforts. Another important objective of this report is to present a knowledge-based design basis for carbon phenolics that combines the analyses of thermochemical decomposition, pore pressure stresses, and thermostructural properties. Possible areas of application of the knowledge-based design include critical material properties development, nozzle component design, and SRM materials control.

Additional historical solid rocket motor burns

NASA Astrophysics Data System (ADS)

Wiedemann, Carsten; Homeister, Maren; Oswald, Michael; Stabroth, Sebastian; Klinkrad, Heiner; Vörsmann, Peter

2009-06-01

The use of orbital solid rocket motors (SRM) is responsible for the release of a high number of slag and Al 2O 3 dust particles which contribute to the space debris environment. This contribution has been modeled for the ESA space debris model MASTER (Meteoroid and Space Debris Terrestrial Environment Reference). The current model version, MASTER-2005, is based on the simulation of 1076 orbital SRM firings which mainly contributed to the long-term debris environment. SRM firings on very low earth orbits which produce only short living particles are not considered. A comparison of the modeled flux with impact data from returned surfaces shows that the shape and quantity of the modeled SRM dust distribution matches that of recent Hubble Space Telescope (HST) solar array measurements very well. However, the absolute flux level for dust is under-predicted for some of the analyzed Long Duration Exposure Facility (LDEF) surfaces. This indicates that some past SRM firings are not included in the current event database. Thus it is necessary to investigate, if additional historical SRM burns, like the retro-burn of low orbiting re-entry capsules, may be responsible for these dust impacts. The most suitable candidates for these firings are the large number of SRM retro-burns of return capsules. This paper focuses on the SRM retro-burns of Russian photoreconnaissance satellites, which were used in high numbers during the time of the LDEF mission. It is discussed which types of satellites and motors may have been responsible for this historical contribution. Altogether, 870 additional SRM retro-burns have been identified. An important task is the identification of such missions to complete the current event data base. Different types of motors have been used to de-orbit both large satellites and small film return capsules. The results of simulation runs are presented.

Inertial Upper Stage Thermal Test Program

DTIC Science & Technology

1989-04-12

EPDM , a tnermal insuiative rubber material covering the SRM ignitor housing, were made in both convective and radiative heater environments under...N2 to ensure an inert environment for these tests. 11 EPDM RUBBER FIBERGLAS PHENOLIC Fig. 2. IUS SRM-2 ignitor. 12 RADIA TOR EMI SHIELD-,," MOVABLE...testing. EPDM Grafoil seal, Viton Thermal-protection materials , IBSTRACT (Continue on reve4 if necessary and identify by block number) An extensive ther

Development of an Ultra-Pure, Carrier-Free 209Po Solution Standard

PubMed Central

Collé, R.; Fitzgerald, R. P.; Laureano-Perez, L.

2015-01-01

Ultra-pure, carrier-free 209Po solution standards have been prepared and standardized for their massic alpha-particle emission rate. The standards, which will be disseminated by the National Institute of Standards and Technology (NIST) as Standard Reference Material SRM 4326a, have a mean mass of (5.169 ± 0.003) g of a solution of polonium in nominal 2.0 mol▪L−1 HCl (having a solution density of (1.032 ± 0.002) g▪ mL−1 at 20 °C) that are contained in 5 mL, flame-sealed, borosilicate glass ampoules. They are certified to contain a 209Po massic alpha-particle emission rate of (39.01 ± 0.18) s−1▪g−1 as of a reference time of 1200 EST, 01 December 2013. This new standard series replaces SRM 4326 that was issued by NIST in 1994. The standardization was based on 4πα liquid scintillation (LS) spectrometry with two different LS counting systems and under wide variations in measurement and counting source conditions. The methodology for the standardization, with corrections for detection of the low-energy conversion electrons from the delayed 2 keV isomeric state in 205Pb and for the radiations accompanying the small 0.45 % electron-capture branch to 209Bi, involves a unique spectral analysis procedure that is specific for the case of 209Po decay. The entire measurement protocol is similar, but revised and improved from that used for SRM 4326. Spectroscopic impurity analyses revealed that no photon-emitting or alpha-emitting radionuclidic impurities were detected. The most common impurity associated with 209Po is 208Po and the activity ratio of 208Po/209Po was < 10−7. PMID:26958444

A Liquid Density Standard Over Wide Ranges of Temperature and Pressure Based on Toluene

PubMed Central

McLinden, Mark O.; Splett, Jolene D.

2008-01-01

The density of liquid toluene has been measured over the temperature range −60 °C to 200 °C with pressures up to 35 MPa. A two-sinker hydrostatic-balance densimeter utilizing a magnetic suspension coupling provided an absolute determination of the density with low uncertainties. These data are the basis of NIST Standard Reference Material® 211d for liquid density over the temperature range −50 °C to 150 °C and pressure range 0.1 MPa to 30 MPa. A thorough uncertainty analysis is presented; this includes effects resulting from the experimental density determination, possible degradation of the sample due to time and exposure to high temperatures, dissolved air, uncertainties in the empirical density model, and the sample-to-sample variations in the SRM vials. Also considered is the effect of uncertainty in the temperature and pressure measurements. This SRM is intended for the calibration of industrial densimeters. PMID:27096111

78 FR 33008 - Consideration of Rulemaking To Address Prompt Remediation of Residual Radioactivity During...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-03

...-0162] Consideration of Rulemaking To Address Prompt Remediation of Residual Radioactivity During... address prompt remediation of residual radioactivity during the operational phase of licensed material... radiological remediation during operations. In the Staff Requirements Memorandum (SRM), SRM-SECY-07-0177...

R Dump Converter without DC Link Capacitor for an 8/6 SRM: Experimental Investigation

PubMed Central

Kavitha, Pasumalaithevan; Umamaheswari, Bhaskaran

2015-01-01

The objective of this paper is to investigate the performance of 8/6 switched reluctance motor (SRM) when excited with sinusoidal voltage. The conventional R dump converter provides DC excitation with the help of capacitor. In this paper the converter used is the modified R dump converter without DC link capacitor providing AC or sinusoidal excitation. Torque ripple and speed ripple are investigated based on hysteresis current control. Constant and sinusoidal current references are considered for comparison in both DC and AC excitation. Extensive theoretical and experimental investigations are made to bring out the merits and demerits of AC versus DC excitation. It is shown that the constructionally simple SRM can be favorably controlled with simple R dump converter with direct AC excitation without need for DC link capacitor. A 4-phase 8/6 0.5 kW SRM is used for experimentation. PMID:25642452

R dump converter without DC link capacitor for an 8/6 SRM: experimental investigation.

PubMed

Kavitha, Pasumalaithevan; Umamaheswari, Bhaskaran

2015-01-01

The objective of this paper is to investigate the performance of 8/6 switched reluctance motor (SRM) when excited with sinusoidal voltage. The conventional R dump converter provides DC excitation with the help of capacitor. In this paper the converter used is the modified R dump converter without DC link capacitor providing AC or sinusoidal excitation. Torque ripple and speed ripple are investigated based on hysteresis current control. Constant and sinusoidal current references are considered for comparison in both DC and AC excitation. Extensive theoretical and experimental investigations are made to bring out the merits and demerits of AC versus DC excitation. It is shown that the constructionally simple SRM can be favorably controlled with simple R dump converter with direct AC excitation without need for DC link capacitor. A 4-phase 8/6 0.5 kW SRM is used for experimentation.

Automated selected reaction monitoring software for accurate label-free protein quantification.

PubMed

Teleman, Johan; Karlsson, Christofer; Waldemarson, Sofia; Hansson, Karin; James, Peter; Malmström, Johan; Levander, Fredrik

2012-07-06

Selected reaction monitoring (SRM) is a mass spectrometry method with documented ability to quantify proteins accurately and reproducibly using labeled reference peptides. However, the use of labeled reference peptides becomes impractical if large numbers of peptides are targeted and when high flexibility is desired when selecting peptides. We have developed a label-free quantitative SRM workflow that relies on a new automated algorithm, Anubis, for accurate peak detection. Anubis efficiently removes interfering signals from contaminating peptides to estimate the true signal of the targeted peptides. We evaluated the algorithm on a published multisite data set and achieved results in line with manual data analysis. In complex peptide mixtures from whole proteome digests of Streptococcus pyogenes we achieved a technical variability across the entire proteome abundance range of 6.5-19.2%, which was considerably below the total variation across biological samples. Our results show that the label-free SRM workflow with automated data analysis is feasible for large-scale biological studies, opening up new possibilities for quantitative proteomics and systems biology.

Methodologies for the Detection of BSE Risk Material in Meat and Meat Products

NASA Astrophysics Data System (ADS)

Lücker, Ernst

Soon after the emergence of bovine spongiform encephalopathy (BSE), a fatal disease of the central nervous system (CNS) in cattle, so-called specified bovine offal were legally defined and banned (SBO-ban) in order to reduce the presumed potential BSE exposition risk for British consumers (UK, 1989). Later on the legal definition of risk material was frequently modified according to new scientific results on BSE tissue infectivity (Table 19.1). A European-wide ban on specified risk materials (SRM) was established in 2001 (EC, 2001). In effect, the SRM-ban is still the most important direct measure in reducing potential human BSE exposure risk (EC, 2005). Taking into account the overall and constant reduction of the frequency of BSE cases as well as the very high costs of preventive measures, the European Commission has envisioned a future lifting of the SRM-ban (EC, 2005).

Analysis of Bisphenol A, Alkylphenols, and Alkylphenol Ethoxylates in NIST SRM 2585 and Indoor House Dust by Gas Chromatography-Tandem Mass Spectrometry (GC/MS/MS).

PubMed

Fan, Xinghua; Kubwabo, Cariton; Wu, Fang; Rasmussen, Pat E

2018-06-26

Background: Ingestion of house dust has been demonstrated to be an important exposure pathway to several contaminants in young children. These compounds include bisphenol A (BPA), alkylphenols (APs), and alkylphenol ethoxylates (APEOs). Analysis of these compounds in house dust is challenging because of the complex composition of the sample matrix. Objective: The objective was to develop a simple and sensitive method to measure BPA, APs, and APEOs in indoor house dust. Methods: An integrated method that involved solvent extraction using sonication, sample cleanup by solid-phase extraction, derivatization by 2,2,2-trifluoro- N -methyl- N -(trimethylsilyl)acetamide, and analysis by GC coupled with tandem MS was developed for the simultaneous determination of BPA, APs, and APEOs in NIST Standard Reference Material (SRM) 2585 (Organic contaminants in house dust) and in settled house dust samples. Results: Target analytes included BPA, 4- tert -octylphenol (OP), OP monoethoxylate, OP diethoxylate, 4- n -nonylphenol (4 n NP), 4 n NP monoethoxylate (4 n NP 1 EO), branched nonylphenol (NP), NP monoethoxylate, NP diethoxylate, NP triethoxylate, and NP tetraethoxylate. The method was sensitive, with method detection limits ranging from 0.05 to 5.1 μg/g, and average recoveries between 82 and 115%. All target analytes were detected in SRM 2585 and house dust except 4 n NP and 4 n NP 1 EO. Conclusions: The method is simple and fast, with high sensitivity and good reproducibility. It is applicable to the analysis of target analytes in similar matrixes, such as sediments, soil, and biosolids. Highlights: Values measured in SRM 2585 will be useful for future research in method development and method comparison.

Preparation and characterization of a suite of ephedra-containing standard reference materials.

PubMed

Sharpless, Katherine E; Anderson, David L; Betz, Joseph M; Butler, Therese A; Capar, Stephen G; Cheng, John; Fraser, Catharine A; Gardner, Graeme; Gay, Martha L; Howell, Daniel W; Ihara, Toshihide; Khan, Mansoor A; Lam, Joseph W; Long, Stephen E; McCooeye, Margaret; Mackey, Elizabeth A; Mindak, William R; Mitvalsky, Staci; Murphy, Karen E; NguyenPho, Agnes; Phinney, Karen W; Porter, Barbara J; Roman, Mark; Sander, Lane C; Satterfield, Mary B; Scriver, Christine; Sturgeon, Ralph; Thomas, Jeanice Brown; Vocke, Robert D; Wise, Stephen A; Wood, Laura J; Yang, Lu; Yen, James H; Ziobro, George C

2006-01-01

The National Institute of Standards and Technology, the U.S. Food and Drug Administration, Center for Drug Evaluation and Research and Center for Food Safety and Applied Nutrition, and the National Institutes of Health, Office of Dietary Supplements, are collaborating to produce a series of Standard Reference Materials (SRMs) for dietary supplements. A suite of ephedra materials is the first in the series, and this paper describes the acquisition, preparation, and value assignment of these materials: SRMs 3240 Ephedra sinica Stapf Aerial Parts, 3241 E. sinica Stapf Native Extract, 3242 E. sinica Stapf Commercial Extract, 3243 Ephedra-Containing Solid Oral Dosage Form, and 3244 Ephedra-Containing Protein Powder. Values are assigned for ephedrine alkaloids and toxic elements in all 5 materials. Values are assigned for other analytes (e.g., caffeine, nutrient elements, proximates, etc.) in some of the materials, as appropriate. Materials in this suite of SRMs are intended for use as primary control materials when values are assigned to in-house (secondary) control materials and for validation of analytical methods for the measurement of alkaloids, toxic elements, and, in the case of SRM 3244, nutrients in similar materials.

Novel approach to study the cardiovascular effects and mechanism of action of urban particulate matter using lung epithelial-endothelial tetra-culture system.

PubMed

Kim, Ha Ryong; Cho, Han Soo; Shin, Da Young; Chung, Kyu Hyuck

2017-02-01

In vitro models have become increasingly sophisticated, and their usefulness in supporting toxicity testing is well established. The present study was designed to establish a novel in vitro model that mimics the cellular network surrounding airways and pulmonary blood vessels, to study the cardiovascular toxic effects of particulate matter (PM). Transwell culture method was used to develop a novel tetra-culture system consisting of tri-cultures (one lung epithelial and two immune cell lines) in the apical chamber and endothelial cells in the basolateral chamber. Tri-cultures were exposed to standard reference material (SRM) 1648a, an urban PM. SRM 1648a did not show cytotoxic effects; however, it increased IL-6 level in apical and basolateral chambers. The cells in the basolateral chamber showed increased monocyte adhesion. Furthermore, exposure of tri-cultured cells to SRM 1648a in the apical chamber induced ICAM-1 expression in endothelial cells in the basolateral chamber by activating the IL-6/STAT3 pathway. In conclusion, a tetra-culture system was established to facilitate the identification of cellular adhesion molecule expression induced by the interaction between pulmonary epithelial and endothelial cells. The tetra-culture system will contribute to elucidation of the relationships between inhalable PM and cardiovascular diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous determination of water-soluble vitamins in SRM 1849 Infant/Adult Nutritional Formula powder by liquid chromatography-isotope dilution mass spectrometry.

PubMed

Goldschmidt, Robert J; Wolf, Wayne R

2010-05-01

Assessing dietary intake of vitamins from all sources, including foods, dietary supplements, and fortified foods, would be aided considerably by having analytical methodologies that are capable of simultaneous determination of several vitamins. Vitamins naturally present in foods may occur in different chemical forms, with levels ranging over several orders of magnitude. Vitamins in dietary supplements and fortified foods, however, are typically added in a single chemical form, and matrix issues are usually not as complex. These sources should thus be relatively amenable to approaches that aim for simultaneous determination of multiple vitamins. Our recent work has focused on development of liquid chromatography (LC)-UV/fluorescence and LC-tandem mass spectrometry methods for the simultaneous determination of water-soluble vitamins (thiamine, niacin, pyridoxine, pantothenic acid, folic acid, biotin, and riboflavin) in dietary supplement tablets and fortified foods, such as formula powders and breakfast cereals. As part of the validation of our methods and collaboration in characterization of a new NIST SRM 1849 Infant/Adult Nutritional Formula powder, we report data on SRM 1849 using isotope dilution mass spectrometric methods. Use of available NIST Standard Reference Materials(R) as test matrices in our method development and validation gives a benchmark for future application of these methods. We compare three chromatographic approaches and provide data on stability of vitamin standard solutions for LC-based multiple vitamin determinations.

Development of Argon Isotope Reference Standards for the U.S. Geological Survey

PubMed Central

Miiller, Archie P.

2006-01-01

The comparison of physical ages of geological materials measured by laboratories engaged in geochronological studies has been limited by the accuracy of mineral standards or monitors for which reported ages have differed by as much as 2 %. In order to address this problem, the U.S. Geological Survey is planning to calibrate the conventional 40Ar/40K age of a new preparation of an international hornblende standard labeled MMhb-2. The 40K concentration in MMhb-2 has already been determined by the Analytical Chemistry Division at NIST with an uncertainty of 0.2 %. The 40Ar concentration will be measured by the USGS using the argon isotope reference standards that were recently developed by NIST and are described in this paper. The isotope standards were constructed in the form of pipette/reservoir systems and calibrated by gas expansion techniques to deliver small high-precision aliquots of high-purity argon. Two of the pipette systems will deliver aliquots of 38Ar having initial molar quantities of 1.567 × 10−10 moles and 2.313 × 10−10 moles with expanded (k = 2) uncertainties of 0.058 % and 0.054 %, respectively. Three other pipette systems will deliver aliquots (nominally 4 × 10−10 moles) of 40Ar:36Ar artificial mixtures with similar accuracy and with molar ratios of 0.9974 ± 0.06 %, 29.69 ± 0.06 %, and 285.7 ± 0.08 % (k = 2). These isotope reference standards will enable the USGS to measure the 40Ar concentration in MMhb-2 with an expanded uncertainty of ≈ 0.1 %. In the process of these measurements, the USGS will re-determine the isotopic composition of atmospheric Ar and calculate a new value for its atomic weight. Upon completion of the USGS calibrations, the MMhb-2 mineral standard will be certified by NIST for its K and Ar concentrations and distributed as a Standard Reference Material (SRM). The new SRM and the NIST-calibrated transportable pipette systems have the potential for dramatically improving the accuracy of interlaboratory calibrations and thereby the measured ages of geological materials, by as much as a factor of ten. PMID:27274937

INAA Application for Trace Element Determination in Biological Reference Material

NASA Astrophysics Data System (ADS)

Atmodjo, D. P. D.; Kurniawati, S.; Lestiani, D. D.; Adventini, N.

2017-06-01

Trace element determination in biological samples is often used in the study of health and toxicology. Determination change to its essentiality and toxicity of trace element require an accurate determination method, which implies that a good Quality Control (QC) procedure should be performed. In this study, QC for trace element determination in biological samples was applied by analyzing the Standard Reference Material (SRM) Bovine muscle 8414 NIST using Instrumental Neutron Activation Analysis (INAA). Three selected trace element such as Fe, Zn, and Se were determined. Accuracy of the elements showed as %recovery and precision as %coefficient of variance (%CV). The result showed that %recovery of Fe, Zn, and Se were in the range between 99.4-107%, 92.7-103%, and 91.9-112%, respectively, whereas %CV were 2.92, 3.70, and 5.37%, respectively. These results showed that INAA method is precise and accurate for trace element determination in biological matrices.

Microbial communities and greenhouse gas emissions associated with the biodegradation of specified risk material in compost

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

Xu, Shanwei; Agriculture and Agri-Food Canada, Lethbridge Research Centre, P.O. Box 3000, Lethbridge, Alberta, Canada T1J 4B1; Reuter, Tim

Highlights: ► Addition of feathers altered bacterial and fungal communities in compost. ► Microbial communities degrading SRM and compost matrix were distinct. ► Addition of feathers may enrich for microbial communities that degrade SRM. ► Inclusion of feather in compost increased both CH{sub 4} and N{sub 2}O emissions from compost. ► Density of methanogens and methanotrophs were weakly associated with CH{sub 4} emissions. - Abstract: Provided that infectious prions (PrP{sup Sc}) are inactivated, composting of specified risk material (SRM) may be a viable alternative to rendering and landfilling. In this study, bacterial and fungal communities as well as greenhouse gasmore » emissions associated with the degradation of SRM were examined in laboratory composters over two 14 day composting cycles. Chicken feathers were mixed into compost to enrich for microbial communities involved in the degradation of keratin and other recalcitrant proteins such as prions. Feathers altered the composition of bacterial and fungal communities primarily during the first cycle. The bacterial genera Saccharomonospora, Thermobifida, Thermoactinomycetaceae, Thiohalospira, Pseudomonas, Actinomadura, and Enterobacter, and the fungal genera Dothideomycetes, Cladosporium, Chaetomium, and Trichaptum were identified as candidates involved in SRM degradation. Feathers increased (P < 0.05) headspace concentrations of CH{sub 4} primarily during the early stages of the first cycle and N{sub 2}O during the second. Although inclusion of feathers in compost increases greenhouse gas emissions, it may promote the establishment of microbial communities that are more adept at degrading SRM and recalcitrant proteins such as keratin and PrP{sup Sc}.« less

Determination of macro and trace elements in multivitamin dietary supplements by high-resolution continuum source graphite furnace atomic absorption spectrometry with slurry sampling.

PubMed

Krawczyk, Magdalena

2014-01-01

In this research, three different commercially available multivitamin dietary supplements were analyzed by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS) with slurry sampling. The concentrations of Cr, Cu, Fe, Mn, and Se were determined and compared to the amounts stated by producers. The safety of multivitamin dietary supplements depends on various factors including the manufacturing process and the purity and origins of the raw ingredients. For this reason, this research determined concentrations of several toxic elements (As, Cd, and Pb). Microwave-assisted high pressure Teflon bomb digestion was used to determine total amounts of elements in samples. Samples were prepared as slurries at a concentration of 0.1% (m/v) for macro elements (Cr, Cu, Fe, Mn, and Se) and at a concentration of % (m/v) for trace elements (As, Cd, and Pb) in acidic media (3M HNO3). The influence of acid concentration, Triton X-100 addition, sonication time, and sonication power on absorbance was investigated. The accuracy of this method was validated by analyses of NRCC LUTS-1 (Lobster hepatopancreas), NRCC DORM-1 (Dogfish Muscle), NRCC DOLT-2 (Dogfish Liver), NBS SRM 1570 (Spinach Leaves) and NBS SRM 1573 (Tomato Leaves) certified reference materials. The measured elements contents in these reference materials (except NRCC DOLT-2) were in satisfactory agreement with the certified values according to the t-test for a 95% confidence level. Copyright © 2013 Elsevier B.V. All rights reserved.

Validation of a Thermo-Ablative Model of Elastomeric Internal Insulation Materials

NASA Technical Reports Server (NTRS)

Martin, Heath T.

2017-01-01

In thermo-ablative material modeling, as in many fields of analysis, the quality of the existing models significantly exceeds that of the experimental data required for their validation. In an effort to narrow this gap, a laboratory-scale internal insulation test bed was developed that exposes insulation samples to realistic solid rocket motor (SRM) internal environments while being instrumented to record real-time rates of both model inputs (i.e., chamber pressure, total surface heat flux, and radiative heat flux) as well as model outputs (i.e., material decomposition depths (MDDs) and in-depth material temperatures). In this work, the measured SRM internal environment parameters were used in conjunction with equilibrium thermochemistry codes as inputs to one-dimensional thermo-ablative models of the PBINBR and CFEPDM insulation samples used in the lab-scale test firings. The computed MDD histories were then compared with those deduced from real-time X-ray radiography of the insulation samples, and the calculated in-depth temperatures were compared with those measured by embedded thermocouples. The results of this exercise emphasize the challenges of modeling and testing elastomeric materials in SRM environments while illuminating the path forward to improved fidelity.

Speciation of Mn(II), Mn(VII) and total manganese in water and food samples by coprecipitation-atomic absorption spectrometry combination.

PubMed

Citak, Demirhan; Tuzen, Mustafa; Soylak, Mustafa

2010-01-15

A speciation procedure based on the coprecipitation of manganese(II) with zirconium(IV) hydroxide has been developed for the investigation of levels of manganese species. The determination of manganese levels was performed by flame atomic absorption spectrometry (FAAS). Total manganese was determined after the reduction of Mn(VII) to Mn(II) by ascorbic acid. The analytical parameters including pH, amount of zirconium(IV), sample volume, etc., were investigated for the quantitative recoveries of manganese(II). The effects of matrix ions were also examined. The recoveries for manganese(II) were in the range of 95-98%. Preconcentration factor was calculated as 50. The detection limit for the analyte ions based on 3 sigma (n=21) was 0.75 microg L(-1) for Mn(II). The relative standard deviation was found to be lower than 7%. The validation of the presented procedure was performed by analysis of certified reference material having different matrices, NIST SRM 1515 (Apple Leaves) and NIST SRM 1568a (Rice Flour). The procedure was successfully applied to natural waters and food samples.

Synthesis of cerium oxide (CeO 2) by co-precipitation for application as a reference material for X-ray powder diffraction peak widths

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

de Lima Batista, Anderson Márcio; Miranda, Marcus Aurélio Ribeiro; Martins, Fátima Itana Chaves Custódio

Several methods can be used to obtain, from powder diffraction patterns, crystallite size and lattice strain of polycrystalline samples. Some examples are the Scherrer equation, Williamson–Hall plots, Warren/Averbach Fourier decomposition, Whole Powder Pattern Modeling, and Debye function analysis. To apply some of these methods, it is necessary to remove the contribution of the instrument to the widths of the diffraction peaks. Nowadays, one of the main samples used for this purpose is the LaB6 SRM660b commercialized by the National Institute of Standard Technology; the width of the diffraction peak of this sample is caused only by the instrumental apparatus. However,more » this sample can be expensive for researchers in developing countries. In this work, the authors present a simple route to obtain micron-sized polycrystalline CeO 2that have a full width at half maximum comparable with the SRM660b and therefore it can be used to remove instrumental broadening.« less

Documentation of operational protocol for the use of MAMA software

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

Schwartz, Daniel S.

2016-01-21

Image analysis of Scanning Electron Microscope (SEM) micrographs is a complex process that can vary significantly between analysts. The factors causing the variation are numerous, and the purpose of Task 2b is to develop and test a set of protocols designed to minimize variation in image analysis between different analysts and laboratories, specifically using the MAMA software package, Version 2.1. The protocols were designed to be “minimally invasive”, so that expert SEM operators will not be overly constrained in the way they analyze particle samples. The protocols will be tested using a round-robin approach where results from expert SEM usersmore » at Los Alamos National Laboratory, Lawrence Livermore National Laboratory, Pacific Northwest National Laboratory, Savannah River National Laboratory, and the National Institute of Standards and Testing will be compared. The variation of the results will be used to quantify uncertainty in the particle image analysis process. The round-robin exercise will proceed with 3 levels of rigor, each with their own set of protocols, as described below in Tasks 2b.1, 2b.2, and 2b.3. The uncertainty will be developed using NIST standard reference material SRM 1984 “Thermal Spray Powder – Particle Size Distribution, Tungsten Carbide/Cobalt (Acicular)” [Reference 1]. Full details are available in the Certificate of Analysis, posted on the NIST website (http://www.nist.gov/srm/).« less

[Determination of trace Cs, Th and U in ten kinds of human autopsy tissues by ICP-MS].

PubMed

Wang, Jing-yu; Zhu, Hong-da; Ouyang, Li; Liu, Ya-qiong; Wang, Xiao-yan; Huang, Zhuo; Wang, Nai-fen; Liu, Hu-sheng

2004-09-01

This paper studied the trace elements Cs, Th and U in ten kinds of human autopsy tissues by ICP-MS. The instrumental operating conditions were optimized for the measurement of Cs, Th and U. Rhodium (Rh) was used as an internal standard element to compensate matrix effect. Detection limits for Th, U and Cs were 5.7-17.8 pg x mL(-1). The recoveries for spiking liver samples were 96%-107%, and their RSDs were 4.8%-8.9%. Reference materials of NIST SRM 8414 Bovine and NIST SRM 1486 Bone Meal were analyzed by the described method, and the analytical results agreed well with the reference values. Human autopsy tissues samples were digested by mixed acid (HNO3 + HClO4). The determination of Cs, Th and U in lung, liver, bone, heart, stomach, spleen, muscle, kidney, thyroid gland and intestinum tenue was performed by ICP-MS without separation and enrichment procedures. The obtained results indicated that this method is rapid, sensitive and accurate; the distribution of the three elements is different from one to another human organ sample; the main organ targets for Th and U are lungs and kidneys; and a coordinated variation of Cs, Th and U concentration in lungs was found in the samples collected from Hebei and Sichuan provinces.

Viscoelastic property tuning for reducing noise radiated by switched-reluctance machines

NASA Astrophysics Data System (ADS)

Millithaler, Pierre; Dupont, Jean-Baptiste; Ouisse, Morvan; Sadoulet-Reboul, Émeline; Bouhaddi, Noureddine

2017-10-01

Switched-reluctance motors (SRM) present major acoustic drawbacks that hinder their use for electric vehicles in spite of widely-acknowledged robustness and low manufacturing costs. Unlike other types of electric machines, a SRM stator is completely encapsulated/potted with a viscoelastic resin. By taking advantage of the high damping capacity that a viscoelastic material has in certain temperature and frequency ranges, this article proposes a tuning methodology for reducing the noise emitted by a SRM in operation. After introducing the aspects the tuning process will focus on, the article details a concrete application consisting in computing representative electromagnetic excitations and then the structural response of the stator including equivalent radiated power levels. An optimised viscoelastic material is determined, with which the peak radiated levels are reduced up to 10 dB in comparison to the initial state. This methodology is implementable for concrete industrial applications as it only relies on common commercial finite-element solvers.

The influence of solid rocket motor retro-burns on the space debris environment

NASA Astrophysics Data System (ADS)

Stabroth, Sebastian; Homeister, Maren; Oswald, Michael; Wiedemann, Carsten; Klinkrad, Heiner; Vörsmann, Peter

The ESA space debris population model MASTER (Meteoroid and Space Debris Terrestrial Environment Reference) considers firings of solid rocket motors (SRM) as a debris source with the associated generation of slag and dust particles. The resulting slag and dust population is a major contribution to the sub-millimetre size debris environment in Earth orbit. The current model version, MASTER-2005, is based on the simulation of 1076 orbital SRM firings which contributed to the long-term debris environment. A comparison of the modelled flux with impact data from returned surfaces shows that the shape and quantity of the modelled SRM dust distribution matches that of recent Hubble Space Telescope (HST) solar array measurements very well. However, the absolute flux level for dust is under-predicted for some of the analysed Long Duration Exposure Facility (LDEF) surfaces. This points into the direction of some past SRM firings not included in the current event database. The most suitable candidates for these firings are the large number of SRM retro-burns of return capsules. Objects released by those firings have highly eccentric orbits with perigees in the lower regions of the atmosphere. Thus, they produce no long-term effect on the debris environment. However, a large number of those firings during the on-orbit time frame of LDEF might lead to an increase of the dust population for some of the LDEF surfaces. In this paper, the influence of SRM retro-burns on the short- and long-term debris environment is analysed. The existing firing database is updated with gathered information of some 800 Russian retro-firings. Each firing is simulated with the MASTER population generation module. The resulting population is compared against the existing background population of SRM slag and dust particles in terms of spatial density and flux predictions.

The shoulder pain and disability index: the construct validity and responsiveness of a region-specific disability measure.

PubMed

Heald, S L; Riddle, D L; Lamb, R L

1997-10-01

The purposes of this study were (1) to assess the construct validity of the Shoulder Pain and Disability Index (SPADI) and (2) to determine whether the SPADI is more responsive than the Sickness Impact Profile (SIP), a generic health status measure. The sample consisted of 94 patients who were diagnosed with a shoulder problem and referred to six outpatient physical therapy clinics. Clinically meaningful change was determined by use of an ordinal rating scale designed to determine whether the patient's shoulder function was improved, the same, or worse following treatment. Spearman rho correlations were calculated for the initial visit SPADI and SIP scores. The standardized response mean (SRM) was used to measure responsiveness for the patients who were judged to be improved. One-tailed paired t tests (alpha = .01) were used to determine whether differences existed among SRM values. Correlations between the SPADI and SIP scores ranged from r = .01 to r = .57. The SRM value was higher for the SPADI total score (SRM = 1.38) than for the SIP total score (SRM = 0.79). Most correlations between SPADI and SIP scores provided support for the construct validity of the SPADI. The SPADI does not appear to strongly reflect occupational and recreational disability and is more responsive than the SIP.

On the isolation of elemental carbon (EC) for micro-molar 14C accelerator mass spectrometry: development of a hybrid reference material for 14C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK) EC isolation procedure

NASA Astrophysics Data System (ADS)

Currie, L. A.; Kessler, J. D.

2005-10-01

The primary objective of the research reported here has been the development of a hybrid reference material (RM) to serve as a test of accuracy for elemental carbon (EC) isotopic (14C) speciation measurements. Such measurements are vital for the quantitative apportionment of fossil and biomass sources of "soot" (EC), the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust), showed a range of results, but since the "truth" was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence (14C in PAH, EC) of measurement validity (Currie et al., 2002). Components of the new Hybrid RM (DiesApple), however, have known 14C and EC composition, and they are nearly orthogonal (isotopically and chemically). NIST SRM 2975 (Forklift Diesel Soot) has little or no 14C, and its major compositional component is EC; SRM 1515 (Apple Leaves) has the 14C content of biomass-C, and it has little or no EC. Thus, the Hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C (char) from SRM 1515 in the EC isolate of the Hybrid RM, as well as a test for conservation of its dominant soot fraction throughout the isolation procedure.

The secondary objective was to employ the Hybrid RM for the comparative evaluation of the thermal optical kinetic (TOK) and thermal optical transmission (TOT) methods for the isolation of EC for micro-molar carbon accelerator mass spectrometry (AMS). As part of this process, the relatively new TOK method was subjected to a critical evaluation and significant development. Key findings of our study are: (1) both methods exhibited biomass-C "leakage"; for TOT, the EC fraction isolated for AMS contained about 8% of the original biomass-C; for TOK, the refractory carbon (RC) isolated contained about 3% of the original biomass-C.; (2) the initial isothermal oxidation stage of the TOK method substantially reduced the transfer of artifact char to the RC fraction, improving isolation capabilities; (3) the Hybrid RM was not equal to the sum of its parts, with matrix interactions inducing premature loss of EC which, however, could be quantified and minimized; (4) the three-stage TOK method provided a superior capability for carbonate quantification at the sub-micromolar level, with "reagent-free" removal of carbonate-C from EC - essential for low-level EC-14C AMS.

A novel sample preparation method using rapid nonheated saponification method for the determination of cholesterol in emulsified foods.

PubMed

Jeong, In-Seek; Kwak, Byung-Man; Ahn, Jang-Hyuk; Leem, Donggil; Yoon, Taehyung; Yoon, Changyong; Jeong, Jayoung; Park, Jung-Min; Kim, Jin-Man

2012-10-01

In this study, nonheated saponification was employed as a novel, rapid, and easy sample preparation method for the determination of cholesterol in emulsified foods. Cholesterol content was analyzed using gas chromatography with a flame ionization detector (GC-FID). The cholesterol extraction method was optimized for maximum recovery from baby food and infant formula. Under these conditions, the optimum extraction solvent was 10 mL ethyl ether per 1 to 2 g sample, and the saponification solution was 0.2 mL KOH in methanol. The cholesterol content in the products was determined to be within the certified range of certified reference materials (CRMs), NIST SRM 1544 and SRM 1849. The results of the recovery test performed using spiked materials were in the range of 98.24% to 99.45% with an relative standard devitation (RSD) between 0.83% and 1.61%. This method could be used to reduce sample pretreatment time and is expected to provide an accurate determination of cholesterol in emulsified food matrices such as infant formula and baby food. A novel, rapid, and easy sample preparation method using nonheated saponification was developed for cholesterol detection in emulsified foods. Recovery tests of CRMs were satisfactory, and the recoveries of spiked materials were accurate and precise. This method was effective and decreased the time required for analysis by 5-fold compared to the official method. © 2012 Institute of Food Technologists®

Real-Time X-ray Radiography Diagnostics of Components in Solid Rocket Motors

NASA Technical Reports Server (NTRS)

Cortopassi, A. C.; Martin, H. T.; Boyer, E.; Kuo, K. K.

2012-01-01

Solid rocket motors (SRMs) typically use nozzle materials which are required to maintain their shape as well as insulate the underlying support structure during the motor operation. In addition, SRMs need internal insulation materials to protect the motor case from the harsh environment resulting from the combustion of solid propellant. In the nozzle, typical materials consist of high density graphite, carbon-carbon composites and carbon phenolic composites. Internal insulation of the motor cases is typically a composite material with carbon, asbestos, Kevlar, or silica fibers in an ablative matrix such as EPDM or NBR. For both nozzle and internal insulation materials, the charring process occurs when the hot combustion products heat the material intensely. The pyrolysis of the matrix material takes away a portion of the thermal energy near the wall surface and leaves behind a char layer. The fiber reinforcement retains the porous char layer which provides continued thermal protection from the hot combustion products. It is of great interest to characterize both the total erosion rates of the material and the char layer thickness. By better understanding of the erosion process for a particular ablative material in a specific flow environment, the required insulation material thickness can be properly selected. The recession rates of internal insulation and nozzle materials of SRMs are typically determined by testing in some sort of simulated environment; either arc-jet testing, flame torch testing, or subscale SRMs of different size. Material recession rates are deduced by comparison of pre- and post-test measurements and then averaging over the duration of the test. However, these averaging techniques cannot be used to determine the instantaneous recession rates of the material. Knowledge of the variation in recession rates in response to the instantaneous flow conditions during the motor operation is of great importance. For example, in many SRM configurations the recession of the solid propellant grain can drastically alter the flow-field and effect the recession of internal insulation and nozzle materials. Simultaneous measurement of the overall erosion rate, the development of the char layer, and the recession of the char-virgin interface during the motor operation can be rather difficult. While invasive techniques have been used with limited success, they have serious drawbacks. Break wires or make wire sensors can be installed into a sufficient number of locations in the charring material from which a time history of the charring surface can be deduced. These sensors fundamentally alter the local structure of the material in which they are imbedded. Also, the location of these sensors within the material is not known precisely without the use of an X-ray. To determine instantaneous recession rates, real-time X-ray radiography (X-ray RTR) has been utilized in several SRM experiments at PSU. The X-ray RTR system discussed in this paper consists of an X-ray source, X-ray image intensifier, and CCD camera connected to a capture computer. The system has been used to examine the ablation process of internal insulation as well as nozzle material erosion in a subscale SRM. The X-ray source is rated to 320 kV at 10 mA and has both a large (5.5 mm) and small (3.0 mm) focal spot. The lead-lined cesium iodide X-ray image intensifier produces an image which is captured by a CCD camera with a 1,000 x 1,000 pixel resolution. To produce accurate imagery of the object of interest, the alignment of the X-ray source to the X-ray image intensifier is crucial. The image sequences captured during the operation of an SRM are then processed to enhance the quality of the images. This procedure allows for computer software to extract data on the total erosion rate and the char layer thickness. Figure 1 Error! Reference source not found.shows a sequence of images captured during the operation the subscale SRM with the X-ray RTR system. The X-rayTR system, alignment procedure, uncertainty determination, and image analysis process will be discussed in detail in the full manuscript.

Grafting 3-mercaptopropyl trimethoxysilane on multi-walled carbon nanotubes surface for improving on-line cadmium(II) preconcentration from water samples.

PubMed

Corazza, Marcela Zanetti; Somera, Bruna Fabrin; Segatelli, Mariana Gava; Tarley, Cesar Ricardo Teixeira

2012-12-01

In the present study, the performance of multi-walled carbon nanotubes (MWCNTs) grafted with 3-mercaptopropyltrimethoxysilane (3-MPTMS), used as a solid phase extractor for Cd(2+) preconcentration in a flow injection system coupled to flame atomic absorption spectrometry (FAAS), was evaluated. The procedure involved the preconcentration of 20.0 mL of Cd(2+) solution at pH 7.5 (0.1 mol L(-1) buffer phosphate) through 70 mg of 3-MPTMS-grafted MWCNTs packed into a minicolumn at 6.0 mL min(-1). The elution step was carried out with 1.0 mol L(-1) HCl. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to estimate the extent of the MWCNT chemical modification. The 3-MPTMS-grafted MWCNTs provided a 1.68 times improvement in the sensitivity of the Cd(2+) FAAS determination compared to the unsilanized oxidized MWCNTs. The following parameters were obtained: preconcentration factor of 31.5, consumptive index of 0.635 mL, sample throughput of 14 h(-1), and concentration efficiency of 9.46 min(-1). The analytical curve was constructed in the range of 1.0-60.0 μg L(-1) (r=0.9988), and the detection and quantification limits were found to be 0.15 μg L(-1) and 0.62 μg L(-1), respectively. Different types of water samples and cigarette sample were successfully analyzed, and the results were compared using electrothermal atomic absorption spectrometry (ETAAS) as reference technique. In addition, the accuracy of proposed method was also checked by analysis of certified reference material NIST SRM 1573a (tomato leaves) and standard reference material NIST SRM 1643e (trace elements in natural waters). Copyright © 2012 Elsevier B.V. All rights reserved.

Automated clean-up, separation and detection of polycyclic aromatic hydrocarbons in particulate matter extracts from urban dust and diesel standard reference materials using a 2D-LC/2D-GC system.

PubMed

Ahmed, Trifa M; Lim, Hwanmi; Bergvall, Christoffer; Westerholm, Roger

2013-10-01

A multidimensional, on-line coupled liquid chromatographic/gas chromatographic system was developed for the quantification of polycyclic aromatic hydrocarbons (PAHs). A two-dimensional liquid chromatographic system (2D-liquid chromatography (LC)), with three columns having different selectivities, was connected on-line to a two-dimensional gas chromatographic system (2D-gas chromatography (GC)). Samples were cleaned up by combining normal elution and column back-flush of the LC columns to selectively remove matrix constituents and isolate well-defined, PAH enriched fractions. Using this system, the sequential removal of polar, mono/diaromatic, olefinic and alkane compounds from crude extracts was achieved. The LC/GC coupling was performed using a fused silica transfer line into a programmable temperature vaporizer (PTV) GC injector. Using the PTV in the solvent vent mode, excess solvent was removed and the enriched PAH sample extract was injected into the GC. The 2D-GC setup consisted of two capillary columns with different stationary phase selectivities. Heart-cutting of selected PAH compounds in the first GC column (first dimension) and transfer of these to the second GC column (second dimension) increased the baseline resolutions of closely eluting PAHs. The on-line system was validated using the standard reference materials SRM 1649a (urban dust) and SRM 1975 (diesel particulate extract). The PAH concentrations measured were comparable to the certified values and the fully automated LC/GC system performed the clean-up, separation and detection of PAHs in 16 extracts in less than 24 h. The multidimensional, on-line 2D-LC/2D-GC system eliminated manual handling of the sample extracts and minimised the risk of sample loss and contamination, while increasing accuracy and precision.

The stable Cr isotopic compositions of chondrites and silicate planetary reservoirs

NASA Astrophysics Data System (ADS)

Schoenberg, Ronny; Merdian, Alexandra; Holmden, Chris; Kleinhanns, Ilka C.; Haßler, Kathrin; Wille, Martin; Reitter, Elmar

2016-06-01

The depletion of chromium in Earth's mantle (∼2700 ppm) in comparison to chondrites (∼4400 ppm) indicates significant incorporation of chromium into the core during our planet's metal-silicate differentiation, assuming that there was no significant escape of the moderately volatile element chromium during the accretionary phase of Earth. Stable Cr isotope compositions - expressed as the ‰-difference in 53Cr/52Cr from the terrestrial reference material SRM979 (δ53/52CrSRM979 values) - of planetary silicate reservoirs might thus yield information about the conditions of planetary metal segregation processes when compared to chondrites. The stable Cr isotopic compositions of 7 carbonaceous chondrites, 11 ordinary chondrites, 5 HED achondrites and 2 martian meteorites determined by a double spike MC-ICP-MS method are within uncertainties indistinguishable from each other and from the previously determined δ53/52CrSRM979 value of -0.124 ± 0.101‰ for the igneous silicate Earth. Extensive quality tests support the accuracy of the stable Cr isotope determinations of various meteorites and terrestrial silicates reported here. The uniformity in stable Cr isotope compositions of samples from planetary silicate mantles and undifferentiated meteorites indicates that metal-silicate differentiation of Earth, Mars and the HED parent body did not cause measurable stable Cr isotope fractionation between these two reservoirs. Our results also imply that the accretionary disc, at least in the inner solar system, was homogeneous in its stable Cr isotopic composition and that potential volatility loss of chromium during accretion of the terrestrial planets was not accompanied by measurable stable isotopic fractionation. Small but reproducible variations in δ53/52CrSRM979 values of terrestrial magmatic rocks point to natural stable Cr isotope variations within Earth's silicate reservoirs. Further and more detailed studies are required to investigate whether silicate differentiation processes, such as partial mantle melting and crystal fractionation, can cause stable Cr isotopic fractionation on Earth and other planetary bodies.

18O-labeled proteome reference as global internal standards for targeted quantification by selected reaction monitoring-mass spectrometry.

PubMed

Kim, Jong-Seo; Fillmore, Thomas L; Liu, Tao; Robinson, Errol; Hossain, Mahmud; Champion, Boyd L; Moore, Ronald J; Camp, David G; Smith, Richard D; Qian, Wei-Jun

2011-12-01

Selected reaction monitoring (SRM)-MS is an emerging technology for high throughput targeted protein quantification and verification in biomarker discovery studies; however, the cost associated with the application of stable isotope-labeled synthetic peptides as internal standards can be prohibitive for screening a large number of candidate proteins as often required in the preverification phase of discovery studies. Herein we present a proof of concept study using an (18)O-labeled proteome reference as global internal standards (GIS) for SRM-based relative quantification. The (18)O-labeled proteome reference (or GIS) can be readily prepared and contains a heavy isotope ((18)O)-labeled internal standard for every possible tryptic peptide. Our results showed that the percentage of heavy isotope ((18)O) incorporation applying an improved protocol was >99.5% for most peptides investigated. The accuracy, reproducibility, and linear dynamic range of quantification were further assessed based on known ratios of standard proteins spiked into the labeled mouse plasma reference. Reliable quantification was observed with high reproducibility (i.e. coefficient of variance <10%) for analyte concentrations that were set at 100-fold higher or lower than those of the GIS based on the light ((16)O)/heavy ((18)O) peak area ratios. The utility of (18)O-labeled GIS was further illustrated by accurate relative quantification of 45 major human plasma proteins. Moreover, quantification of the concentrations of C-reactive protein and prostate-specific antigen was illustrated by coupling the GIS with standard additions of purified protein standards. Collectively, our results demonstrated that the use of (18)O-labeled proteome reference as GIS provides a convenient, low cost, and effective strategy for relative quantification of a large number of candidate proteins in biological or clinical samples using SRM.

The Influence of Solid Rocket Motor Retro-Burns on the Space Debris Environment

NASA Astrophysics Data System (ADS)

Stabroth, S.; Homeister, M.; Oswald, M.; Wiedemann, C.; Klinkrad, H.; Vörsmann, P.

The ESA space debris population model MASTER Meteoroid and Space Debris Terrestrial Environment Reference considers firings of solid rocket motors SRM as a debris source with the associated generation of slag and dust particles The resulting slag and dust population is a major contribution to the sub-millimetre size debris environment in Earth orbit The current model version MASTER-2005 is based on the simulation of 1 076 orbital SRM firings which contributed to the long-term debris environment A comparison of the modelled flux with impact data from returned surfaces shows that the shape and quantity of the modelled SRM dust distribution matches that of recent Hubble Space Telescope HST solar array measurements very well However the absolute flux level for dust is under-predicted for some of the analysed Long Duration Exposure Facility LDEF surfaces This points into the direction of some past SRM firings not included in the current event database The most suitable candidates for these firings are the large number of SRM retro-burns of return capsules Objects released by those firings have highly eccentric orbits with perigees in the lower regions of the atmosphere Thus they produce no long-term effect on the debris environment However a large number of those firings during the on-orbit time frame of LDEF might lead to an increase of the dust population for some of the LDEF surfaces In this paper the influence of SRM retro-burns on the short- and long-term debris environment is analysed The existing firing database is updated with gathered

Analysis of Human Plasma Metabolites across Different Liquid Chromatography - Mass Spectrometry Platforms: Cross-platform Transferable Chemical Signatures

PubMed Central

Telu, Kelly H.; Yan, Xinjian; Wallace, William E.; Stein, Stephen E.; Simón-Manso, Yamil

2016-01-01

RATIONALE The metabolite profiling of a NIST plasma Standard Reference Material (SRM 1950) on different LC-MS platforms showed significant differences. Although these findings suggest caution when interpreting metabolomics results, the degree of overlap of both profiles allowed us to use tandem mass spectral libraries of recurrent spectra to evaluate to what extent these results are transferable across platforms and to develop cross-platform chemical signatures. METHODS Non-targeted global metabolite profiles of SRM 1950 were obtained on different LC-MS platforms using reversed phase chromatography and different chromatographic scales (nano, conventional and UHPLC). The data processing and the metabolite differential analysis were carried out using publically available (XCMS), proprietary (Mass Profiler Professional) and in-house software (NIST pipeline). RESULTS Repeatability and intermediate precision showed that the non-targeted SRM 1950 profiling was highly reproducible when working on the same platform (RSD < 2%); however, substantial differences were found in the LC-MS patterns originating on different platforms or even using different chromatographic scales (conventional HPLC, UHPLC and nanoLC) on the same platform. A substantial degree of overlap (common molecular features) was also found. A procedure to generate consistent chemical signatures using tandem mass spectral libraries of recurrent spectra is proposed. CONLUSIONS Different platforms rendered significantly different metabolite profiles, but the results were highly reproducible when working within one platform. Tandem mass spectral libraries of recurrent spectra are proposed to evaluate the degree of transferability of chemical signatures generated on different platforms. Chemical signatures based on our procedure are most likely cross-platform transferable. PMID:26842580

Rapid Quantitation of Ascorbic and Folic Acids in SRM 3280 Multivitamin/Multielement Tablets using Flow-Injection Tandem Mass Spectrometry

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

Bhandari, Deepak; Kertesz, Vilmos; Van Berkel, Gary J

RATIONALE: Ascorbic acid (AA) and folic acid (FA) are water-soluble vitamins and are usually fortified in food and dietary supplements. For the safety of human health, proper intake of these vitamins is recommended. Improvement in the analysis time required for the quantitative determination of these vitamins in food and nutritional formulations is desired. METHODS: A simple and fast (~5 min) in-tube sample preparation was performed, independently for FA and AA, by mixing extraction solvent with a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Quantitative detection was achieved by flow-injection (1 L injectionmore » volume) electrospray ionization tandem mass spectrometry (ESI-MS/MS) in negative ion mode using the method of standard addition. RESULTS: Method of standard addition was employed for the quantitative estimation of each vitamin in a sample extract. At least 2 spiked and 1 non-spiked sample extract were injected in triplicate for each quantitative analysis. Given an injection-to-injection interval of approximately 2 min, about 18 min was required to complete the quantitative estimation of each vitamin. The concentration values obtained for the respective vitamins in the standard reference material (SRM) 3280 using this approach were within the statistical range of the certified values provided in the NIST Certificate of Analysis. The estimated limit of detections of FA and AA were 13 and 5.9 ng/g, respectively. CONCLUSIONS: Flow-injection ESI-MS/MS was successfully applied for the rapid quantitation of FA and AA in SRM 3280 multivitamin/multielement tablets.« less

Development of a standard reference material for Cr(vi) in contaminated soil

USGS Publications Warehouse

Nagourney, S.J.; Wilson, S.A.; Buckley, B.; Kingston, H.M.S.; Yang, S.-Y.; Long, S.E.

2008-01-01

Over the last several decades, considerable contamination by hexavalent chromium has resulted from the land disposal of Chromite Ore Processing Residue (COPR). COPR contains a number of hexavalent chromium-bearing compounds that were produced in high temperature industrial processes. Concern over the carcinogenic potential of this chromium species, and its environmental mobility, has resulted in efforts to remediate these waste sites. To provide support to analytical measurements of hexavalent chromium, a candidate National Institute of Standards and Technology (NIST) Standard Reference Material?? (SRM 2701), having a hexavalent chromium content of approximately 500 mg kg -1, has been developed using material collected from a waste site in Hudson County, New Jersey, USA. The collection, processing, preparation and preliminary physico-chemical characterization of the material are discussed. A two-phase multi-laboratory testing study was carried out to provide data on material homogeneity and to assess the stability of the material over the duration of the study. The study was designed to incorporate several United States Environmental Protection Agency (USEPA) determinative methods for hexavalent chromium, including Method 6800 which is based on speciated isotope dilution mass spectrometry (SIDMS), an approach which can account for chromium species inter-conversion during the extraction and measurement sequence. This journal is ?? The Royal Society of Chemistry 2008.

46 CFR Sec. 2 - Description of NSA-WORKSMALREP Contract.

Code of Federal Regulations, 2010 CFR

2010-10-01

... competitive bids, spot bids, or by negotiation for the performance of ship repair work. NSA Order No. 46 (SRM... bids, spot bids or negotiation, therefore, further reference thereto will not be made herein. ...

230Th-234U Model-Ages of Some Uranium Standard Reference Materials

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

Williams, R W; Gaffney, A M; Kristo, M J

The 'age' of a sample of uranium is an important aspect of a nuclear forensic investigation and of the attribution of the material to its source. To the extent that the sample obeys the standard rules of radiochronometry, then the production ages of even very recent material can be determined using the {sup 230}Th-{sup 234}U chronometer. These standard rules may be summarized as (a) the daughter/parent ratio at time=zero must be known, and (b) there has been no daughter/parent fractionation since production. For most samples of uranium, the 'ages' determined using this chronometer are semantically 'model-ages' because (a) some assumptionmore » of the initial {sup 230}Th content in the sample is required and (b) closed-system behavior is assumed. The uranium standard reference materials originally prepared and distributed by the former US National Bureau of Standards and now distributed by New Brunswick Laboratory as certified reference materials (NBS SRM = NBL CRM) are good candidates for samples where both rules are met. The U isotopic standards have known purification and production dates, and closed-system behavior in the solid form (U{sub 3}O{sub 8}) may be assumed with confidence. We present here {sup 230}Th-{sup 234}U model-ages for several of these standards, determined by isotope dilution mass spectrometry using a multicollector ICP-MS, and compare these ages with their known production history.« less

Analysis of human plasma metabolites across different liquid chromatography/mass spectrometry platforms: Cross-platform transferable chemical signatures.

PubMed

Telu, Kelly H; Yan, Xinjian; Wallace, William E; Stein, Stephen E; Simón-Manso, Yamil

2016-03-15

The metabolite profiling of a NIST plasma Standard Reference Material (SRM 1950) on different liquid chromatography/mass spectrometry (LC/MS) platforms showed significant differences. Although these findings suggest caution when interpreting metabolomics results, the degree of overlap of both profiles allowed us to use tandem mass spectral libraries of recurrent spectra to evaluate to what extent these results are transferable across platforms and to develop cross-platform chemical signatures. Non-targeted global metabolite profiles of SRM 1950 were obtained on different LC/MS platforms using reversed-phase chromatography and different chromatographic scales (conventional HPLC, UHPLC and nanoLC). The data processing and the metabolite differential analysis were carried out using publically available (XCMS), proprietary (Mass Profiler Professional) and in-house software (NIST pipeline). Repeatability and intermediate precision showed that the non-targeted SRM 1950 profiling was highly reproducible when working on the same platform (relative standard deviation (RSD) <2%); however, substantial differences were found in the LC/MS patterns originating on different platforms or even using different chromatographic scales (conventional HPLC, UHPLC and nanoLC) on the same platform. A substantial degree of overlap (common molecular features) was also found. A procedure to generate consistent chemical signatures using tandem mass spectral libraries of recurrent spectra is proposed. Different platforms rendered significantly different metabolite profiles, but the results were highly reproducible when working within one platform. Tandem mass spectral libraries of recurrent spectra are proposed to evaluate the degree of transferability of chemical signatures generated on different platforms. Chemical signatures based on our procedure are most likely cross-platform transferable. Published in 2016. This article is a U.S. Government work and is in the public domain in the USA.

Isotope-ratio measurements of lead in NIST standard reference materials by multiple-collector inductively coupled plasma mass spectrometry.

PubMed

Platzner, I; Ehrlich, S; Halicz, L

2001-07-01

The capability of a second-generation Nu Instruments multiple collector inductively coupled plasma mass spectrometer (MC-ICP-MS) has been evaluated for precise and accurate isotope-ratio determinations of lead. Essentially the mass spectrometer is a double-focusing instrument of Nier-Johnson analyzer geometry equipped with a newly designed variable-dispersion ion optical device, enabling the measured ion beams to be focused into a fixed array of Faraday collectors and an ion-counting assembly. NIST SRM Pb 981, 982, and 983 isotopic standards were used. Addition of thallium to the lead standards and subsequent simultaneous measurement of the thallium and lead isotopes enabled correction for mass discrimination, by use of the exponential correction law and 205Tl/203Tl = 2.3875. Six measurements of SRM Pb-982 furnished the results 206Pb/204Pb = 36.7326(68), 207Pb/204Pb = 17.1543(30), 208Pb/204Pb = 36.7249(69), 207Pb/206Pb = 0.46700(1), and 208Pb/206Pb = 0.99979(2); the NIST-certified values were 36.738(37), 17.159(25), 36.744(50), 0.46707(20), and 1.00016(36), respectively. Direct isotope lead analysis in silicates can be performed without any chemical separation. NIST SRM 610 glass was dissolved and introduced into the MC-ICP-MS by means of a micro concentric nebulizer. The ratios observed were in excellent agreement with previously reported data obtained by TIMS and laser ablation MC-ICP-MS, despite the high Ca/Pb concentration ratio (200/1) and the presence of many other elements at levels comparable with that of lead. Approximately 0.2 microg lead are sufficient for isotope analysis with ratio uncertainties between 240 and 530 ppm.

Simultaneous determination of thirteen organophosphate esters in settled indoor house dust and a comparison between two sampling techniques.

PubMed

Fan, Xinghua; Kubwabo, Cariton; Rasmussen, Pat E; Wu, Fang

2014-09-01

An analytical method for the simultaneous determination of 13 organophosphate esters (OPEs) in house dust was developed. The method is based on solvent extraction by sonication, sample cleanup by solid phase extraction (SPE), and analysis by gas chromatography-positive chemical ionization-tandem mass spectrometry (GC/PCI-MS/MS). Method detection limits (MDLs) ranged from 0.03 to 0.43 μg/g and recoveries from 60% to 118%. The inter- and intra-day variations ranged from 3% to 23%. The method was applied to dust samples collected using two vacuum sampling techniques from 134 urban Canadian homes: a sample of fresh or "active" dust (FD) collected by technicians and a composite sample taken from the household vacuum cleaner (HD). Results show that the two sampling methods (i.e., FD vs HD) provided comparable results. Tributoxyethyl phosphate (TBEP), triphenyl phosphate (TPhP), tris(chloropropyl) phosphate (TCPP), tri(2-chloroethyl) phosphate (TCEP), tris(dichloro-isopropyl) phosphate (TDCPP), tricresyl phosphate (TCrP), and tri-n-butyl phosphate (TnBP) were detected in the majority of samples. The most predominant OPE was TBEP, with median concentrations of 31.9 μg/g and 22.8 μg/g in FD and HD samples, respectively, 1 to 2 orders of magnitude higher than other OPEs. The method was also applied to the analysis of OPEs in the National Institute of Standards and Technology (NIST) standard reference material (NIST SRM 2585, organic contaminants in house dust). The results from SRM 2585 may contribute to the certification of OPE concentration values in this SRM. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Spectral characterization of near-infrared acousto-optic tunable filter (AOTF) hyperspectral imaging systems using standard calibration materials.

PubMed

Bürmen, Miran; Pernuš, Franjo; Likar, Boštjan

2011-04-01

In this study, we propose and evaluate a method for spectral characterization of acousto-optic tunable filter (AOTF) hyperspectral imaging systems in the near-infrared (NIR) spectral region from 900 nm to 1700 nm. The proposed spectral characterization method is based on the SRM-2035 standard reference material, exhibiting distinct spectral features, which enables robust non-rigid matching of the acquired and reference spectra. The matching is performed by simultaneously optimizing the parameters of the AOTF tuning curve, spectral resolution, baseline, and multiplicative effects. In this way, the tuning curve (frequency-wavelength characteristics) and the corresponding spectral resolution of the AOTF hyperspectral imaging system can be characterized simultaneously. Also, the method enables simple spectral characterization of the entire imaging plane of hyperspectral imaging systems. The results indicate that the method is accurate and efficient and can easily be integrated with systems operating in diffuse reflection or transmission modes. Therefore, the proposed method is suitable for characterization, calibration, or validation of AOTF hyperspectral imaging systems. © 2011 Society for Applied Spectroscopy

Acid digestion of geological and environmental samples using open-vessel focused microwave digestion.

PubMed

Taylor, Vivien F; Toms, Andrew; Longerich, Henry P

2002-01-01

The application of open vessel focused microwave acid digestion is described for the preparation of geological and environmental samples for analysis using inductively coupled plasma-mass spectrometry (ICP-MS). The method is compared to conventional closed-vessel high pressure methods which are limited in the use of HF to break down silicates. Open-vessel acid digestion more conveniently enables the use of HF to remove Si from geological and plant samples as volatile SiF4, as well as evaporation-to-dryness and sequential acid addition during the procedure. Rock reference materials (G-2 granite, MRG-1 gabbros, SY-2 syenite, JA-1 andesite, and JB-2 and SRM-688 basalts) and plant reference materials (BCR and IAEA lichens, peach leaves, apple leaves, Durham wheat flour, and pine needles) were digested with results comparable to conventional hotplate digestion. The microwave digestion method gave poor results for granitic samples containing refractory minerals, however fusion was the preferred method of preparation for these samples. Sample preparation time was reduced from several days, using conventional hotplate digestion method, to one hour per sample using our microwave method.

A simulation analysis of phase processing circuitry in the Ohio University Omega receiver prototype

NASA Technical Reports Server (NTRS)

Palkovic, R. A.

1975-01-01

A FORTRAN IV simulation study of the all-digital phase-processing circuitry is described. A digital phase-lock loop (DPLL) forms the heart of the Omega navigation receiver prototype, and through the DPLL, the phase of the 10.2 KHz Omega signal was estimated when the true signal phase is contaminated with noise. The DPLL uses a frequency synthesizer as the reference oscillator. The synthesizer is composed of synchronous rate multipliers (SRM's) driven by a temperature-compensated crystal oscillator, and the use of the SRM's in this application introduces phase jitter which degrades system performance. Simulation of the frequency synthesizer discussed was to analyze the circuits on a bit-by-bit level in order to evaluate the overall design, to see easily the effects of proposed design changes prior to actual breadboarding, to determine the optimum integration time for the DPLL in an environment typical of general aviation conditions, and to quantify the phase error introduced by the SRM synthesizer and examine its effect on the system.

Effect of collision energy optimization on the measurement of peptides by selected reaction monitoring (SRM) mass spectrometry.

PubMed

Maclean, Brendan; Tomazela, Daniela M; Abbatiello, Susan E; Zhang, Shucha; Whiteaker, Jeffrey R; Paulovich, Amanda G; Carr, Steven A; Maccoss, Michael J

2010-12-15

Proteomics experiments based on Selected Reaction Monitoring (SRM, also referred to as Multiple Reaction Monitoring or MRM) are being used to target large numbers of protein candidates in complex mixtures. At present, instrument parameters are often optimized for each peptide, a time and resource intensive process. Large SRM experiments are greatly facilitated by having the ability to predict MS instrument parameters that work well with the broad diversity of peptides they target. For this reason, we investigated the impact of using simple linear equations to predict the collision energy (CE) on peptide signal intensity and compared it with the empirical optimization of the CE for each peptide and transition individually. Using optimized linear equations, the difference between predicted and empirically derived CE values was found to be an average gain of only 7.8% of total peak area. We also found that existing commonly used linear equations fall short of their potential, and should be recalculated for each charge state and when introducing new instrument platforms. We provide a fully automated pipeline for calculating these equations and individually optimizing CE of each transition on SRM instruments from Agilent, Applied Biosystems, Thermo-Scientific and Waters in the open source Skyline software tool ( http://proteome.gs.washington.edu/software/skyline ).

Applications of surface metrology in firearm identification

NASA Astrophysics Data System (ADS)

Zheng, X.; Soons, J.; Vorburger, T. V.; Song, J.; Renegar, T.; Thompson, R.

2014-01-01

Surface metrology is commonly used to characterize functional engineering surfaces. The technologies developed offer opportunities to improve forensic toolmark identification. Toolmarks are created when a hard surface, the tool, comes into contact with a softer surface and causes plastic deformation. Toolmarks are commonly found on fired bullets and cartridge cases. Trained firearms examiners use these toolmarks to link an evidence bullet or cartridge case to a specific firearm, which can lead to a criminal conviction. Currently, identification is typically based on qualitative visual comparison by a trained examiner using a comparison microscope. In 2009, a report by the National Academies called this method into question. Amongst other issues, they questioned the objectivity of visual toolmark identification by firearms examiners. The National Academies recommended the development of objective toolmark identification criteria and confidence limits. The National Institute of Standards and Technology (NIST) have applied its experience in surface metrology to develop objective identification criteria, measurement methods, and reference artefacts for toolmark identification. NIST developed the Standard Reference Material SRM 2460 standard bullet and SRM 2461 standard cartridge case to facilitate quality control and traceability of identifications performed in crime laboratories. Objectivity is improved through measurement of surface topography and application of unambiguous surface similarity metrics, such as the maximum value (ACCFMAX) of the areal cross correlation function. Case studies were performed on consecutively manufactured tools, such as gun barrels and breech faces, to demonstrate that, even in this worst case scenario, all the tested tools imparted unique surface topographies that were identifiable. These studies provide scientific support for toolmark evidence admissibility in criminal court cases.

NHANES Monitoring of Serum 25-Hydroxyvitamin D: A Roundtable Summary123

PubMed Central

Yetley, Elizabeth A.; Pfeiffer, Christine M.; Schleicher, Rosemary L.; Phinney, Karen W.; Lacher, David A.; Christakos, Sylvia; Eckfeldt, John H.; Fleet, James C.; Howard, George; Hoofnagle, Andrew N.; Hui, Siu L.; Lensmeyer, Gary L.; Massaro, Joseph; Peacock, Munro; Rosner, Bernard; Wiebe, Donald; Bailey, Regan L.; Coates, Paul M.; Looker, Anne C.; Sempos, Christopher; Johnson, Clifford L.; Picciano, Mary Frances

2010-01-01

A roundtable to discuss monitoring of serum 25-hydroxyvitamin D [25(OH)D] in the NHANES was held in late July 2009. Topics included the following: 1) options for dealing with assay fluctuations in serum 25(OH)D in the NHANES conducted between 1988 and 2006; 2) approaches for transitioning between the RIA used in the NHANES between 1988 and 2006 to the liquid chromatography tandem MS (LC-MS/MS) measurement procedure to be used in NHANES 2007 and later; 3) approaches for integrating the recently available standard reference material for vitamin D in human serum (SRM 972) from the National Institute of Standards and Technology (NIST) into the NHANES; 4) questions regarding whether the C-3 epimer of 25-hydroxyvitamin D3 [3-epi-25(OH)D3] should be measured in NHANES 2007 and later; and 5) identification of research and educational needs. The roundtable experts agreed that the NHANES data needed to be adjusted to control for assay fluctuations and offered several options for addressing this issue. The experts suggested that the LC-MS/MS measurement procedure developed by NIST could serve as a higher order reference measurement procedure. They noted the need for a commutability study for the recently released NIST SRM 972 across a range of measurement procedures. They suggested that federal agencies and professional organizations work with manufacturers to improve the quality and comparability of measurement procedures across all laboratories. The experts noted the preliminary nature of the evidence of the 3-epi-25(OH)D3 but felt that it should be measured in 2007 NHANES and later. PMID:20881084

Assessment of SRM, MRM(3) , and DIA for the targeted analysis of phosphorylation dynamics in non-small cell lung cancer.

PubMed

Schmidlin, Thierry; Garrigues, Luc; Lane, Catherine S; Mulder, T Celine; van Doorn, Sander; Post, Harm; de Graaf, Erik L; Lemeer, Simone; Heck, Albert J R; Altelaar, A F Maarten

2016-08-01

Hypothesis-driven MS-based targeted proteomics has gained great popularity in a relatively short timespan. Next to the widely established selected reaction monitoring (SRM) workflow, data-independent acquisition (DIA), also referred to as sequential window acquisition of all theoretical spectra (SWATH) was introduced as a high-throughput targeted proteomics method. DIA facilitates increased proteome coverage, however, does not yet reach the sensitivity obtained with SRM. Therefore, a well-informed method selection is crucial for designing a successful targeted proteomics experiment. This is especially the case when targeting less conventional peptides such as those that contain PTMs, as these peptides do not always adhere to the optimal fragmentation considerations for targeted assays. Here, we provide insight into the performance of DIA, SRM, and MRM cubed (MRM(3) ) in the analysis of phosphorylation dynamics throughout the phosphoinositide 3-kinase mechanistic target of rapamycin (PI3K-mTOR) and mitogen-activated protein kinase (MAPK) signaling network. We observe indeed that DIA is less sensitive when compared to SRM, however demonstrates increased flexibility, by postanalysis selection of alternative phosphopeptide precursors. Additionally, we demonstrate the added benefit of MRM(3) , allowing the quantification of two poorly accessible phosphosites. In total, targeted proteomics enabled the quantification of 42 PI3K-mTOR and MAPK phosphosites, gaining a so far unachieved in-depth view mTOR signaling events linked to tyrosine kinase inhibitor resistance in non-small cell lung cancer. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comprehensive Chemical Characterization of Hydrocarbons in NIST Standard Reference Material 2779 Gulf of Mexico Crude Oil

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

Worton, David R.; Zhang, Haofei; Isaacman-VanWertz, Gabriel

Comprehensive chemical information is needed to understand the environmental fate and impact of hydrocarbons released during oil spills. However, chemical information remains incomplete because of the limitations of current analytical techniques and the inherent chemical complexity of crude oils. In this study, gas chromatography (GC)-amenable C 9-C 33 hydrocarbons were comprehensively characterized from the National Institute of Standards and Technology Standard Reference Material (NIST SRM) 2779 Gulf of Mexico crude oil by GC coupled to vacuum ultraviolet photoionization mass spectrometry (GC/VUV-MS), with a mass balance of 68 ± 22%. This technique overcomes one important limitation faced by traditional GC andmore » even comprehensive 2D gas chromatography (GC×GC): the necessity for individual compounds to be chromatographically resolved from one another in order to be characterized. VUV photoionization minimizes fragmentation of the molecular ions, facilitating the characterization of the observed hydrocarbons as a function of molecular weight (carbon number, N C), structure (number of double bond equivalents, N DBE), and mass fraction (mg kg -1), which represent important metrics for understanding their fate and environmental impacts. Linear alkanes (8 ± 1%), bran ched alkanes (11 ± 2%), and cycloalkanes (37 ± 12%) dominated the mass with the largest contribution from cycloalkanes containing one or two rings and one or more alkyl side chains (27 ± 9%). Linearity and good agreement with previous work for a subset of >100 components and for the sum of compound classes provided confidence in our measurements and represents the first independent assessment of our analytical approach and calibration methodology. Another crude oil collected from the Marlin platform (35 km northeast of the Macondo well) was shown to be chemically identical within experimental errors to NIST SRM 2779, demonstrating that Marlin crude is an appropriate surrogate oil for researchers conducting laboratory research into impacts of the DeepWater Horizon disaster.« less

Comprehensive Chemical Characterization of Hydrocarbons in NIST Standard Reference Material 2779 Gulf of Mexico Crude Oil

DOE PAGES

Worton, David R.; Zhang, Haofei; Isaacman-VanWertz, Gabriel; ...

2015-10-13

Comprehensive chemical information is needed to understand the environmental fate and impact of hydrocarbons released during oil spills. However, chemical information remains incomplete because of the limitations of current analytical techniques and the inherent chemical complexity of crude oils. In this study, gas chromatography (GC)-amenable C 9-C 33 hydrocarbons were comprehensively characterized from the National Institute of Standards and Technology Standard Reference Material (NIST SRM) 2779 Gulf of Mexico crude oil by GC coupled to vacuum ultraviolet photoionization mass spectrometry (GC/VUV-MS), with a mass balance of 68 ± 22%. This technique overcomes one important limitation faced by traditional GC andmore » even comprehensive 2D gas chromatography (GC×GC): the necessity for individual compounds to be chromatographically resolved from one another in order to be characterized. VUV photoionization minimizes fragmentation of the molecular ions, facilitating the characterization of the observed hydrocarbons as a function of molecular weight (carbon number, N C), structure (number of double bond equivalents, N DBE), and mass fraction (mg kg -1), which represent important metrics for understanding their fate and environmental impacts. Linear alkanes (8 ± 1%), bran ched alkanes (11 ± 2%), and cycloalkanes (37 ± 12%) dominated the mass with the largest contribution from cycloalkanes containing one or two rings and one or more alkyl side chains (27 ± 9%). Linearity and good agreement with previous work for a subset of >100 components and for the sum of compound classes provided confidence in our measurements and represents the first independent assessment of our analytical approach and calibration methodology. Another crude oil collected from the Marlin platform (35 km northeast of the Macondo well) was shown to be chemically identical within experimental errors to NIST SRM 2779, demonstrating that Marlin crude is an appropriate surrogate oil for researchers conducting laboratory research into impacts of the DeepWater Horizon disaster.« less

Comprehensive Chemical Characterization of Hydrocarbons in NIST Standard Reference Material 2779 Gulf of Mexico Crude Oil.

PubMed

Worton, David R; Zhang, Haofei; Isaacman-VanWertz, Gabriel; Chan, Arthur W H; Wilson, Kevin R; Goldstein, Allen H

2015-11-17

Comprehensive chemical information is needed to understand the environmental fate and impact of hydrocarbons released during oil spills. However, chemical information remains incomplete because of the limitations of current analytical techniques and the inherent chemical complexity of crude oils. In this work, gas chromatography (GC)-amenable C9-C33 hydrocarbons were comprehensively characterized from the National Institute of Standards and Technology Standard Reference Material (NIST SRM) 2779 Gulf of Mexico crude oil by GC coupled to vacuum ultraviolet photoionization mass spectrometry (GC/VUV-MS), with a mass balance of 68 ± 22%. This technique overcomes one important limitation faced by traditional GC and even comprehensive 2D gas chromatography (GC×GC): the necessity for individual compounds to be chromatographically resolved from one another in order to be characterized. VUV photoionization minimizes fragmentation of the molecular ions, facilitating the characterization of the observed hydrocarbons as a function of molecular weight (carbon number, NC), structure (number of double bond equivalents, NDBE), and mass fraction (mg kg(-1)), which represent important metrics for understanding their fate and environmental impacts. Linear alkanes (8 ± 1%), branched alkanes (11 ± 2%), and cycloalkanes (37 ± 12%) dominated the mass with the largest contribution from cycloalkanes containing one or two rings and one or more alkyl side chains (27 ± 9%). Linearity and good agreement with previous work for a subset of >100 components and for the sum of compound classes provided confidence in our measurements and represents the first independent assessment of our analytical approach and calibration methodology. Another crude oil collected from the Marlin platform (35 km northeast of the Macondo well) was shown to be chemically identical within experimental errors to NIST SRM 2779, demonstrating that Marlin crude is an appropriate surrogate oil for researchers conducting laboratory research into impacts of the DeepWater Horizon disaster.

Dynamic Simulation of VEGA SRM Bench Firing By Using Propellant Complex Characterization

NASA Astrophysics Data System (ADS)

Di Trapani, C. D.; Mastrella, E.; Bartoccini, D.; Squeo, E. A.; Mastroddi, F.; Coppotelli, G.; Linari, M.

2012-07-01

During the VEGA launcher development, from the 2004 up to now, 8 firing tests have been performed at Salto di Quirra (Sardinia, Italy) and Kourou (Guyana, Fr) with the objective to characterize and qualify of the Zefiros and P80 Solid Rocket Motors (SRM). In fact the VEGA launcher configuration foreseen 3 solid stages based on P80, Z23 and Z9 Solid Rocket Motors respectively. One of the primary objectives of the firing test is to correctly characterize the dynamic response of the SRM in order to apply such a characterization to the predictions and simulations of the VEGA launch dynamic environment. Considering that the solid propellant is around 90% of the SRM mass, it is very important to dynamically characterize it, and to increase the confidence in the simulation of the dynamic levels transmitted to the LV upper part from the SRMs. The activity is articulated in three parts: • consolidation of an experimental method for the dynamic characterization of the complex dynamic elasticity modulus of elasticity of visco-elastic materials applicable to the SRM propellant operative conditions • introduction of the complex dynamic elasticity modulus in a numerical FEM benchmark based on MSC NASTRAN solver • analysis of the effect of the introduction of the complex dynamic elasticity modulus in the Zefiros FEM focusing on experimental firing test data reproduction with numerical approach.

Attenuation of Diabetic Conditions by Sida rhombifolia in Moderately Diabetic Rats and Inability to Produce Similar Effects in Severely Diabetic in Rats.

PubMed

Chaturvedi, Padmaja; Kwape, Tebogo Elvis

2015-12-01

This study was done out to evaluate the effects of Sida rhombifolia methanol extract (SRM) on diabetes in moderately diabetic (MD) and severely diabetic (SD) Sprague-Dawley rats. SRM was prepared by soaking the powdered plant material in 70% methanol and rota evaporating the methanol from the extract. Effective hypoglycemic doses were established by performing oral glucose tolerance tests (OGTTs) in normal rats. Hourly effects of SRM on glucose were observed in the MD and the SD rats. Rats were grouped, five rats to a group, into normal control 1 (NC1), MD control 1 (MDC1), MD experimental 1 (MDE1), SD control 1 (SDC1), and SD experimental 1 (SDE1) groups. All rats in the control groups were administered 1 mL of distilled water (DW). The rats in the MDE1 and the SDE1 groups were administered SRM orally at 200 and 300 mg/kg body weight (BW), respectively, dissolved in 1 mL of DW. Blood was collected initially and at intervals of 1 hour for 6 hours to measure blood glucose. A similar experimental design was followed for the 30-day long-term trial. Finally, rats were sacrificed, and blood was collected to measure blood glucose, lipid profiles, thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH). OGTTs indicated that two doses (200 and 300 mg/kg BW) were effective hypoglycemic doses in normal rats. Both doses reduced glucose levels after 1 hour in the MDE1 and the SDE1 groups. A long-term trial of SRM in the MD group showed a reduced glucose level, a normal lipid profile, and normal GSH and TBARS levels. In SD rats, SRM had no statistically significant effects on these parameters. Normal weight was achieved in the MD rats, but the SD rats showed reduced BW. The study demonstrates that SRM has potential to alleviate the conditions of moderate diabetic, but not severe diabetes.

Two-Phase Exhumation of the Santa Rosa Mountains: Low- and High-Angle Normal Faulting During Initiation and Evolution of the Southern San Andreas Fault System

NASA Astrophysics Data System (ADS)

Mason, Cody C.; Spotila, James A.; Axen, Gary; Dorsey, Rebecca J.; Luther, Amy; Stockli, Daniel F.

2017-12-01

Low-angle detachment fault systems are important elements of oblique-divergent plate boundaries, yet the role detachment faulting plays in the development of such boundaries is poorly understood. The West Salton Detachment Fault (WSDF) is a major low-angle normal fault that formed coeval with localization of the Pacific-North America plate boundary in the northern Salton Trough, CA. Apatite U-Th/He thermochronometry (AHe; n = 29 samples) and thermal history modeling of samples from the Santa Rosa Mountains (SRM) reveal that initial exhumation along the WSDF began at circa 8 Ma, exhuming footwall material from depths of >2 to 3 km. An uplifted fossil (Miocene) helium partial retention zone is present in the eastern SRM, while a deeper crustal section has been exhumed along the Pleistocene high-angle Santa Rosa Fault (SFR) to much higher elevations in the southwest SRM. Detachment-related vertical exhumation rates in the SRM were 0.15-0.36 km/Myr, with maximum fault slip rates of 1.2-3.0 km/Myr. Miocene AHe isochrons across the SRM are consistent with northeast crustal tilting of the SRM block and suggest that the post-WSDF vertical exhumation rate along the SRF was 1.3 km/Myr. The timing of extension initiation in the Salton Trough suggests that clockwise rotation of relative plate motions that began at 8 Ma is associated with initiation of the southern San Andreas system. Pleistocene regional tectonic reorganization was contemporaneous with an abrupt transition from low- to high-angle faulting and indicates that local fault geometry may at times exert a fundamental control on rock uplift rates along strike-slip fault systems.

Bioassay-directed fractionation and salmonella mutagenicity of automobile and forklift diesel exhaust particles.

PubMed Central

DeMarini, David M; Brooks, Lance R; Warren, Sarah H; Kobayashi, Takahiro; Gilmour, M Ian; Singh, Pramila

2004-01-01

Many pulmonary toxicity studies of diesel exhaust particles (DEPs) have used an automobile-generated sample (A-DEPs) whose mutagenicity has not been reported. In contrast, many mutagenicity studies of DEPs have used a forklift-generated sample (SRM 2975) that has been evaluated in only a few pulmonary toxicity studies. Therefore, we evaluated the mutagenicity of both DEPs in Salmonella coupled to a bioassay-directed fractionation. The percentage of extractable organic material (EOM) was 26.3% for A-DEPs and 2% for SRM 2975. Most of the A-EOM (~55%) eluted in the hexane fraction, reflecting the presence of alkanes and alkenes, typical of uncombusted fuel. In contrast, most of the SRM 2975 EOM (~58%) eluted in the polar methanol fraction, indicative of oxygenated and/or nitrated organics derived from combustion. Most of the direct-acting, base-substitution activity of the A-EOM eluted in the hexane/dichloromethane (DCM) fraction, but this activity eluted in the polar methanol fraction for the SRM 2975 EOM. The direct-acting frameshift mutagenicity eluted across fractions of A-EOM, whereas > 80% eluted only in the DCM fraction of SRM 2975 EOM. The A-DEPs were more mutagenic than SRM 2975 per mass of particle, having 227 times more polycyclic aromatic hydrocarbon-type and 8-45 more nitroarene-type mutagenic activity. These differences were associated with the different conditions under which the two DEP samples were generated and collected. A comprehensive understanding of the mechanisms responsible for the health effects of DEPs requires the evaluation of DEP standards for a variety of end points, and our results highlight the need for multidisciplinary studies on a variety of representative samples of DEPs. PMID:15175166

Absolute quantitation of low abundance plasma APL1β peptides at sub-fmol/mL Level by SRM/MRM without immunoaffinity enrichment.

PubMed

Sano, Shozo; Tagami, Shinji; Hashimoto, Yuuki; Yoshizawa-Kumagaye, Kumiko; Tsunemi, Masahiko; Okochi, Masayasu; Tomonaga, Takeshi

2014-02-07

Selected/multiple reaction monitoring (SRM/MRM) has been widely used for the quantification of specific proteins/peptides, although it is still challenging to quantitate low abundant proteins/peptides in complex samples such as plasma/serum. To overcome this problem, enrichment of target proteins/peptides is needed, such as immunoprecipitation; however, this is labor-intense and generation of antibodies is highly expensive. In this study, we attempted to quantify plasma low abundant APLP1-derived Aβ-like peptides (APL1β), a surrogate marker for Alzheimer's disease, by SRM/MRM using stable isotope-labeled reference peptides without immunoaffinity enrichment. A combination of Cibacron Blue dye mediated albumin removal and acetonitrile extraction followed by C18-strong cation exchange multi-StageTip purification was used to deplete plasma proteins and unnecessary peptides. Optimal and validated precursor ions to fragment ion transitions of APL1β were developed on a triple quadruple mass spectrometer, and the nanoliquid chromatography gradient for peptide separation was optimized to minimize the biological interference of plasma. Using the stable isotope-labeled (SI) peptide as an internal control, absolute concentrations of plasma APL1β peptide could be quantified as several hundred amol/mL. To our knowledge, this is the lowest detection level of endogenous plasma peptide quantified by SRM/MRM.

Correlative Super-Resolution Microscopy: New Dimensions and New Opportunities.

PubMed

Hauser, Meghan; Wojcik, Michal; Kim, Doory; Mahmoudi, Morteza; Li, Wan; Xu, Ke

2017-06-14

Correlative microscopy, the integration of two or more microscopy techniques performed on the same sample, produces results that emphasize the strengths of each technique while offsetting their individual weaknesses. Light microscopy has historically been a central method in correlative microscopy due to its widespread availability, compatibility with hydrated and live biological samples, and excellent molecular specificity through fluorescence labeling. However, conventional light microscopy can only achieve a resolution of ∼300 nm, undercutting its advantages in correlations with higher-resolution methods. The rise of super-resolution microscopy (SRM) over the past decade has drastically improved the resolution of light microscopy to ∼10 nm, thus creating exciting new opportunities and challenges for correlative microscopy. Here we review how these challenges are addressed to effectively correlate SRM with other microscopy techniques, including light microscopy, electron microscopy, cryomicroscopy, atomic force microscopy, and various forms of spectroscopy. Though we emphasize biological studies, we also discuss the application of correlative SRM to materials characterization and single-molecule reactions. Finally, we point out current limitations and discuss possible future improvements and advances. We thus demonstrate how a correlative approach adds new dimensions of information and provides new opportunities in the fast-growing field of SRM.

A simple way to measure daily lifestyle regularity

NASA Technical Reports Server (NTRS)

Monk, Timothy H.; Frank, Ellen; Potts, Jaime M.; Kupfer, David J.

2002-01-01

A brief diary instrument to quantify daily lifestyle regularity (SRM-5) is developed and compared with a much longer version of the instrument (SRM-17) described and used previously. Three studies are described. In Study 1, SRM-17 scores (2 weeks) were collected from a total of 293 healthy control subjects (both genders) aged between 19 and 92 years. Five items (1) Get out of bed, (2) First contact with another person, (3) Start work, housework or volunteer activities, (4) Have dinner, and (5) Go to bed were then selected from the 17 items and SRM-5 scores calculated as if these five items were the only ones collected. Comparisons were made with SRM-17 scores from the same subject-weeks, looking at correlations between the two SRM measures, and the effects of age and gender on lifestyle regularity as measured by the two instruments. In Study 2 this process was repeated in a group of 27 subjects who were in remission from unipolar depression after treatment with psychotherapy and who completed SRM-17 for at least 20 successive weeks. SRM-5 and SRM-17 scores were then correlated within an individual using time as the random variable, allowing an indication of how successful SRM-5 was in tracking changes in lifestyle regularity (within an individual) over time. In Study 3 an SRM-5 diary instrument was administered to 101 healthy control subjects (both genders, aged 20-59 years) for two successive weeks to obtain normative measures and to test for correlations with age and morningness. Measures of lifestyle regularity from SRM-5 correlated quite well (about 0.8) with those from SRM-17 both between subjects, and within-subjects over time. As a detector of irregularity as defined by SRM-17, the SRM-5 instrument showed acceptable values of kappa (0.69), sensitivity (74%) and specificity (95%). There were, however, differences in mean level, with SRM-5 scores being about 0.9 units [about one standard deviation (SD)] above SRM-17 scores from the same subject-weeks. SRM-5 scores also deviated more from a Gaussian distribution than did SRM-17 ones. In a study with a sample size of 101, the new SRM-5 instrument yielded scores with a mean of 4.11 and an SD of 1.13. Correlations between lifestyle regularity and age, and between lifestyle regularity and morningness appeared similar whether 5-item or 17-item SRM measures were used. When a gender difference in lifestyle regularity appeared, it was detected by both SRM-5 and SRM-17 measures.

Free and combined amino acids in size-segregated atmospheric aerosol samples

NASA Astrophysics Data System (ADS)

Di Filippo, Patrizia; Pomata, Donatella; Riccardi, Carmela; Buiarelli, Francesca; Gallo, Valentina; Quaranta, Alessandro

2014-12-01

Concentrations of free and combined amino acids in an urban atmosphere and their distributions in size-segregated particles were investigated in the cold and warm seasons. In particular this article provides the first investigation of protein bioaerosol concentrations in ultrafine fraction (PM0.1) of particulate matter. In addition the present work provides amino acid and total proteinaceous material concentrations in NIST SRM 1649b, useful as reference values. The reference material was also used to build matrix matched calibration curves. Free amino acid total content in winter and summer PM0.1 was respectively 48.0 and 94.4 ng m-3, representing about 0.7 and 7.4% by weight of urban particulate matter in the two seasons. Total airborne protein and peptide concentrations in the same ultrafine fractions were 93.6 and 449.9 ng m-3 respectively in winter and in summer, representing 7.5 and 35.4% w/w of PM0.1, and demonstrating an exceptionally high percentage in summer ultrafine fraction. The significant potential adverse health effects of ultrafine particulate matter include allergies mainly caused by protein particles and we assumed that in summer 162 ng h-1 of proteinaceous material, by means of ultrafine particles, can penetrate from the lungs into the bloodstream.

238U/235U determinations of some commonly used reference materials and U-bearing accessory minerals (Invited)

NASA Astrophysics Data System (ADS)

Condon, D.; Noble, S.; McLean, N.; Bowring, S. A.

2009-12-01

We have determined 238U/235U ratios for a suite of commonly used natural (CRM 112a, SRM 950a, HU-1) and synthetic (IRMM 184 and CRM U500) uranium reference materials in addition to several U-bearing accessory phases (zircon and monazite) by thermal ionisation mass-spectrometry (TIMS) using the IRMM 3636 233U-236U double spike to accurately correct for mass fractionation. The 238U/235U values for the natural uranium reference materials differ, by up to 0.1%, from the widely used ‘consensus’ value (137.88) with all having 238U/235U values less than 137.88. Similarly, initial 238U/235U data from zircon and monazite yield 238U/235U values that are lower than the ‘consensus’ value. The data obtained from U-bearing minerals is used to assess how the uncertainty in the 238U/235U ratio contributes to the systematic discordance observed in 238U/206Pb and 235U/207Pb dates (Mattinson, 2000; Schoene et al., 2006) which has traditionally been wholly attributed to error in the U decay constants. The 238U/235U determinations made on the synthetic reference materials yield results that are considerably more precise and accurate than the certified values (0.02% vs. 0.1% for CRM U500). The calibration of isotopic tracers used for U-daughter geochronology that are partially based upon these reference materials, and the resultant age determinations, will benefit from increased accuracy and precision. Mattinson, J.M., 2000. Revising the “gold standard”—the uranium decay constants of Jaffey et al., 1971. Eos Trans. AGU, Spring Meet. Suppl., Abstract V61A-02. Schoene B., Crowley J.L., Condon D.C., Schmitz M.D., Bowring S.A., 2006, Reassessing the uranium decay constants for geochronology using ID-TIMS U-Pb data. Geochimica et Cosmochimica Acta 70: 426-445

Workshop on standards in biomass for energy and chemicals: proceedings

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

Milne, T.A.

1984-11-01

In the course of reviewing standards literature, visiting prominent laboratories and research groups, attending biomass meetings and corresponding widely, a whole set of standards needs was identified, the most prominent of which were: biomass standard reference materials, research materials and sample banks; special collections of microorganisms, clonal material, algae, etc.; standard methods of characterization of substrates and biomass fuels; standard tests and methods for the conversion and end-use of biomass; standard protocols for the description, harvesting, preparation, storage, and measurement of productivity of biomass materials in the energy context; glossaries of terms; development of special tests for assay of enzymaticmore » activity and related processes. There was also a recognition of the need for government, professional and industry support of concensus standards development and the dissemination of information on standards. Some 45 biomass researchers and managers met with key NBS staff to identify and prioritize standards needs. This was done through three working panels: the Panel on Standard Reference Materials (SRM's), Research Materials (RM's), and Sample Banks; the Panel on Production and Characterization; and the Panel on Tests and Methods for Conversion and End Use. This report gives a summary of the action items in standards development recommended unanimously by the workshop attendees. The proceedings of the workshop, and an appendix, contain an extensive written record of the findings of the workshop panelists and others regarding presently existing standards and standards issues and needs. Separate abstracts have been prepared for selected papers for inclusion in the Energy Database.« less

Evaluation of a tunable bandpass reaction cell for an inductively coupled plasma mass spectrometer for the determination of chromium and vanadium in serum and urine

NASA Astrophysics Data System (ADS)

Nixon, David E.; Neubauer, Kenneth R.; Eckdahl, Steven J.; Butz, John A.; Burritt, Mary F.

2002-05-01

A Dynamic Reaction Cell™ inductively coupled argon plasma mass spectrometer (DRC-ICP-MS) was evaluated for the determination of chromium and vanadium in serum and urine. Reaction cell conditions were evaluated for the elimination of ArC + and ClOH + interferences on chromium at mass 52 and OCl + on vanadium at mass 51. A diluent containing only 1% nitric acid and internal standards (Y and Ga) was used to prepare serum and urine for analysis. Instrument response calibration was achieved by using aqueous acidic standards spiked into pooled sera or urine matrices. The slopes of the calibration curves prepared in urine and serum matrices were nearly identical. On average, chromium detection limits are 2.5 times lower using the DRC than Zeeman graphite furnace atomic absorption spectrometry (ZGFAAS). Vanadium detection limits are approximately 50 times lower. Average detection limits achieved with DRC-ICP-MS are 0.075 μg Cr/l and 0.028 μg V/l. Average results for the analysis of National Institute of Standards and Technology Standard Reference Material (NIST SRM) 1598 Bovine Serum (attained over 22 days) are: 0.14 μg Cr/l and 0.068 μg V/l. The reference concentrations for vanadium and chromium in NIST SRM 1598 are (0.06) μg V/l and 0.14±0.08 μg Cr/l, respectively. Results for chromium and vanadium determinations on ICP-MS survey samples from the Toxocologie du Quebec are equivalent to those reported by high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for the same survey samples.

Microwave digestion for the quantification of inorganic elements in coal and coal ash using ICP-OES.

PubMed

Low, Fiona; Zhang, Lian

2012-11-15

In this paper, microwave digestion conditions have been optimised to achieve complete recoveries for the ash-forming inorganic elements in coal and coal combustion fly ash, during the analysis by inductively coupled plasma optical emission spectroscopy (ICP-OES). The elements analysed include six major (Al, Ca, Fe, K, Mg and Na) and twelve trace (As, Ba, Be, Co, Cr, Cu, Li, Mn, Ni, Pb, Sr and V). Seven reference samples have been tested, including two standard coal references, SRM1632c and SARM19, their corresponding high-temperature ashes (HTAs), and three coal fly ash references, SRM1633c, SRM2690 and BCR38. The recoveries of individual elements in these samples have been examined intensively, as a function of the amount of hydrofluoric acid (HF, 0-2.0 ml), microwave power (900 W vs. 1200 W) and sample mass (0.05 g vs. 0.1 g). As have been confirmed, the recoveries of these individual elements varied significantly with the microwave digestion condition, elemental type and sample property. For the coal references and their HTAs, the use of HF can be ruled out for most of the elements, except K associated with feldspar, Pb and V. In particular, the recovery of Pb in coal is highly sample-specific and thus unpredictable. The majority of elements in fly ash references require the use of 0.1-0.2 ml HF for a complete recovery. Al in fly ash is the only exceptional element which gave incomplete recoveries throughout, suggesting the use of a complementary technique for its quantification. As has proven to be the only element inconsequential of sample type and digestion conditions, achieving complete recoveries for all cases. On the power parameter, using a higher power such as 1200 W is critical, which has proved to be an ultimatum for the recovery of certain elements, especially in fly ash. Halving sample mass from 0.1 g to 0.05 g was also found to be insignificant. Copyright © 2012 Elsevier B.V. All rights reserved.

Graphite furnace atomic absorption spectrometric detection of vanadium in water and food samples after solid phase extraction on multiwalled carbon nanotubes.

PubMed

Wadhwa, Sham Kumar; Tuzen, Mustafa; Gul Kazi, Tasneem; Soylak, Mustafa

2013-11-15

Vanadium(V) ions as 8-hydroxyquinoline chelates were loaded on multiwalled carbon nanotubes (MWNTs) in a mini chromatographic column. Vanadium was determined by graphite furnace atomic absorption spectrometry (GFAAS). Various analytical parameters including pH of the working solutions, amounts of 8-hydroxyquinoline, eluent type, sample volume, and flow rates were investigated. The effects of matrix ions and some transition metals were also studied. The column can be reused 250 times without any loss in its sorption properties. The preconcentration factor was found as 100. Detection limit (3 s) and limit of quantification (10 s) for the vanadium in the optimal conditions were observed to be 0.012 µg L(-1) and 0.040 μg L(-1), respectively. The capacity of adsorption was 9.6 mg g(-1). Relative standard deviation (RSD) was found to be 5%. The validation of the method was confirmed by using NIST SRM 1515 Apple leaves, NIST SRM 1570a Spinach leaves and GBW 07605 Tea certified reference materials. The procedure was applied to the determination of vanadium in tap water and bottled drinking water samples. The procedure was also successfully applied to microwave digested food samples including black tea, coffee, tomato, cabbage, zucchini, apple and chicken samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Evaluation of Flow-Injection Tandem Mass Spectrometry for Rapid and High-Throughput Quantitative Determination of B-Vitamins in Nutritional Supplements

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

Bhandari, Deepak; Van Berkel, Gary J

2012-01-01

The use of flow-injection electrospray ionization tandem mass spectrometry for rapid and high-throughput mass spectral analysis of selected B-vitamins, viz. B1, B2, B3, B5, and B6, in nutritional formulations was demonstrated. A simple and rapid (~5 min) in-tube sample preparation was performed by adding extraction solvent to a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Automated flow injection introduced 1 L of the extracts directly into the mass spectrometer ion source without chromatographic separation. Sample-to-sample analysis time was 60 s representing significant improvement over conventional liquid chromatography approaches which typically require 25-45more » min, and often require more significant sample preparation procedures. Quantitative capabilities of the flow-injection analysis were tested using the method of standard additions and NIST standard reference material (SRM 3280) multivitamin/multielement tablets. The quantity determined for each B-vitamin in SRM 3280 was within the statistical range provided for the respective certified values. The same sample preparation and analysis approach was also applied to two different commercial vitamin supplement tablets and proved to be successful in the quantification of the selected B-vitamins as evidenced by an agreement with the labels values and the results obtained using isotope dilution liquid chromatography/mass spectrometry.« less

Determination of cadmium in grains by isotope dilution ICP-MS and coprecipitation using sample constituents as carrier precipitants.

PubMed

Inagaki, Kazumi; Narukawa, Tomohiro; Yarita, Takashi; Takatsu, Akiko; Okamoto, Kensaku; Chiba, Koichi

2007-10-01

A coprecipitation method using sample constituents as carrier precipitants was developed that can remove molybdenum, which interferes with the determination of cadmium in grain samples via isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). Samples were digested with HNO3, HF, and HClO4, and then purified 6 M sodium hydroxide solution was added to generate colloidal hydrolysis compounds, mainly magnesium hydroxide. Cadmium can be effectively separated from molybdenum because the cadmium forms hydroxides and adsorbs onto and/or is occluded in the colloid, while the molybdenum does not form hydroxides or adsorb onto the hydrolysis colloid. The colloid was separated by centrifugation and then dissolved with 0.2 M HNO3 solution to recover the cadmium. The recovery of Cd achieved using the coprecipitation was >97%, and the removal efficiency of Mo was approximately 99.9%. An extremely low procedural blank (below the detection limit of ICPMS) was achieved by purifying the 6 M sodium hydroxide solution via Mg coprecipitation using Mg(NO3)2 solution. The proposed method was applied to two certified reference materials (NIST SRM 1567a wheat flour and SRM 1568a rice flour) and CCQM-P64 soybean powder. Good analytical results with small uncertainties were obtained for all samples. This method is simple and reliable for the determination of Cd in grain samples by ID-ICPMS.

Semiautomatic sequential extraction of polycyclic aromatic hydrocarbons and elemental bio-accessible fraction by accelerated solvent extraction on a single particulate matter sample.

PubMed

Astolfi, Maria Luisa; Di Filippo, Patrizia; Gentili, Alessandra; Canepari, Silvia

2017-11-01

We describe the optimization and validation of a sequential extractive method for the determination of the polycyclic aromatic hydrocarbons (PAHs) and elements (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se, V and Zn) that are chemically fractionated into bio-accessible and mineralized residual fractions on a single particulate matter filter. The extraction is performed by automatic accelerated solvent extraction (ASE); samples are sequentially treated with dichloromethane/acetone (4:1) for PAHs extraction and acetate buffer (0.01M; pH 4.5) for elements extraction (bio-accessible fraction). The remaining solid sample is then collected and subjected to acid digestion with HNO 3 :H 2 O 2 (2:1) to determine the mineralized residual element fraction. We also describe a homemade ASE cell that reduces the blank values for most elements; in this cell, the steel frit was replaced by a Teflon pierced disk and a Teflon cylinder was used as the filler. The performance of the proposed method was evaluated in terms of recovery from standard reference material (SRM 1648 and SRM 1649a) and repeatability. The equivalence between the new ASE method and conventional methods was verified for PAHs and for bio-accessible and mineralized residual fractions of elements on PM 10 twin filters. Copyright © 2017 Elsevier B.V. All rights reserved.

Attenuation of Diabetic Conditions by Sida rhombifolia in Moderately Diabetic Rats and Inability to Produce Similar Effects in Severely Diabetic in Rats

PubMed Central

Chaturvedi, Padmaja; Kwape, Tebogo Elvis

2015-01-01

Objectives: This study was done out to evaluate the effects of Sida rhombifolia methanol extract (SRM) on diabetes in moderately diabetic (MD) and severely diabetic (SD) Sprague-Dawley rats. Methods: SRM was prepared by soaking the powdered plant material in 70% methanol and rota evaporating the methanol from the extract. Effective hypoglycemic doses were established by performing oral glucose tolerance tests (OGTTs) in normal rats. Hourly effects of SRM on glucose were observed in the MD and the SD rats. Rats were grouped, five rats to a group, into normal control 1 (NC1), MD control 1 (MDC1), MD experimental 1 (MDE1), SD control 1 (SDC1), and SD experimental 1 (SDE1) groups. All rats in the control groups were administered 1 mL of distilled water (DW). The rats in the MDE1 and the SDE1 groups were administered SRM orally at 200 and 300 mg/kg body weight (BW), respectively, dissolved in 1 mL of DW. Blood was collected initially and at intervals of 1 hour for 6 hours to measure blood glucose. A similar experimental design was followed for the 30-day long-term trial. Finally, rats were sacrificed, and blood was collected to measure blood glucose, lipid profiles, thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH). Results: OGTTs indicated that two doses (200 and 300 mg/kg BW) were effective hypoglycemic doses in normal rats. Both doses reduced glucose levels after 1 hour in the MDE1 and the SDE1 groups. A long-term trial of SRM in the MD group showed a reduced glucose level, a normal lipid profile, and normal GSH and TBARS levels. In SD rats, SRM had no statistically significant effects on these parameters. Normal weight was achieved in the MD rats, but the SD rats showed reduced BW. Conclusion: The study demonstrates that SRM has potential to alleviate the conditions of moderate diabetic, but not severe diabetes. PMID:26998385

[The matrix effects of organic acid compounds in ICP-MS].

PubMed

Nie, Xi-Du; He, Xiao-Mei; Li, Li-Bo; Xie, Hua-Lin

2007-07-01

The matrix effects arising from oxalic acid, lactic acid, tartaric acid and citric acid in inductively coupled plasma mass spectrometry (ICP-MS) were investigated. It has been proved that the sensitivity of analytes can be significantly enhanced by adding small amounts of organic acid compounds with adjusted nebulizer gas flow-rate, especially for the elements with ionization potential between 9 and 11 eV. The tartaric acid has higher enhancement effect on the signal intensity of the hard-to-ionize elements than oxalic acid, lactic acid and citric acid. The mechanism of the enhancement was investigated. The method has been used to determine Be, Zn, As, Se, Sb and Hg in water standard reference materials (SRM). The analytical results are very close to the certified values.

Sub-fragmentation of structural-reactive-material casings under explosion

NASA Astrophysics Data System (ADS)

Zhang, Fan

2015-06-01

The sub-fragmentation of structural reactive material (SRM) thick-casings is to generate fine fragments during casing fragmentation under explosive loading for their efficient energy release to enhance air blast. This has been investigated using a cylindrical casing made from either rich Al-MoO3 or Al-W-based granular composites. The former composite was to study the concept of reactive hot spots where the reaction of reactive particles, which were distributed into base SRM in a fuel-rich equivalence ratio, created heat and gas products during SRM fragmentation. The expansion of these distributed hot spots initiated local fractures of the casing, leading to fine fragments. The Al-W-based composite investigated the concept of impedance mismatch, where shock dynamics at the interfaces of different impedance ingredients resulted in non-uniform, high local temperatures and stresses and late in times the dissimilar inertia resulted in different accelerations, leading to material separation and fine fragments. The casings were manufactured through both hot iso-static pressing and cold gas dynamic spray deposition. Explosion experiments were conducted in a 3 m diameter, 23 m3 cylindrical chamber for these cased charges in a casing-to-explosive mass ratio of 1.75. The results demonstrated the presence of fine fragments and more efficient fragment combustion, compared with previous results, and indicated the effectiveness of both concepts. This work was jointly funded by Defence R&D Canada and the Advanced Energetics Program of DTRA (Dr. William H. Wilson).

An Evaluation of Partial Digestion Protocols for the Extraction and Measurement of Trace Metals of Environmental Concern in Marine and Estuarine Sediments

NASA Astrophysics Data System (ADS)

Winters, S. J.; Krahforst, C.; Sherman, L.; Kehm, K.

2013-12-01

As part of a broad study of the fate and transport of trace metals in estuarine sediments (Krahforst et al., 2013), the efficacy of commonly-used partial digestion protocols, including ISO 11466 (treatment with aqua regia), EPA 3050B (nitric acid followed by H2O2) and a modified rock digestion method ('RD' method- H2O2 followed by nitric), were evaluated for two NIST SRM materials, marine sediment 2702 and estuarine sediment 1646a. Unlike so-called total sediment digestions, the methods studied in this work do not employ hydrofluoric acid and are thought to leave silicates substantially or wholly intact. These methods can in principle compliment studies based on total digestions by providing information about trace metals in phases that are potentially more labile in the marine environment. Samples were digested in ~150 mg aliquots. Application of ISO 11466 and EPA 3050B followed published protocols except that digestions were carried out in trace-metal clean 15 mL capped Teflon vessels in an Al block digester and, at the end of the procedure, the supernatant was decanted from undigested material following repeated centrifugation in 2% nitric acid. Digested solutions were analyzed for Al, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Ag, Cd, Sn and Pb content by ICPMS. All elements were analyzed in collision reaction cell mode to minimize isobaric interferences, except Cd and Ag, which were analyzed in standard mode. Instrument performance was monitored in-run by analyzing the SRM 1643e and several quality-check standards. Two repeated digestions of SRM 2702 and SRM 1646a using EPA 3050B produced identical yields, within the standard deviation of repeated analyses (0 - 5%), for all analyzed elements except Cu, which varied by 30% for SRM 2702. The same was true for ISO 11466, although the standard deviation of repeated analyses for this digestion series tended to be larger (< ~15%). The RD method, which consists of pre-treatment with H2O2 followed by repeated treatments with nitric acid, produced the highest average yields for all elements, ranging from 50% of the Al in SRM 2702 up to ~100% for Cd and Pb. The higher recoveries for the RD method may indicate that pre-treatment with H2O2 more effectively removes organics compared with the conventional methods. Yields for ISO 11466 digestions typically range from 5 - 15% higher than EPA 3050B for all studied elements. Comparisons between the two sediments demonstrated that the acid-extractable fraction differs for several elements. For example results from all three digestion methods confirm a ~40% difference in yield for Mn between SRM 2702 and SRM 1646a. Overall, the results indicate that yields for trace element analyses of marine and estuarine sediments resulting from partial digestion are sensitive to the digestion technique, and in particular the methods employed for removal of organic phases. This work was supported by NSF Grant EAR-0922733 and a Maryland Sea Grant Program Development Award.

The residual and temperature-dependent resistance of reference-grade platinum wire below 13.8 K

NASA Astrophysics Data System (ADS)

Tew, W. L.; Murdock, W. E.; Chojnacky, M. J.; Ripple, D. C.

2013-09-01

We report the Residual Resistance Ratio (RRR) and resistance ratio W(GaMP) (gallium melting point) values for well-annealed samples of the original NIST platinum thermoelectric standard (SRM 1967), for its contemporary substitute SRM 1967a, and for a collection of NIST capsule-type SPRTs. The RRR dependence on annealing temperature is investigated and our results are compared with calculations based on contemporary chemical impurity analyses. The data are corrected to remove temperature-dependent components to derive the RRR at 0 K using W(T) data over the range 1 K

SRM Manual, Selected Resource Materials: Description and Evaluation.

ERIC Educational Resources Information Center

Alberta Dept. of Education, Edmonton. Special Educational Services Branch.

Provided in the manual is descriptive and evaluative information on 67 instructional materials or programs frequently used with exceptional children in Alberta schools. A flow chart describes the three methods of using the manual: l) to obtain descriptive and evaluative information of an instruction program in the manual 2) to classify and record…

46 CFR Sec. 5 - General Agent's authority to effect payment of duties.

Code of Federal Regulations, 2012 CFR

2012-10-01

... AUTHORITY GENERAL AGENT'S RESPONSIBILITY IN CONNECTION WITH FOREIGN REPAIR CUSTOM'S ENTRIES Sec. 5 General... section 3 of SRM-4 do not prevail, the General Agent shall effect payment of duties imposed by Customs and... cases, he shall refer the matter to the appropriate Coast Director for his (The Director) determination...

46 CFR Sec. 5 - General Agent's authority to effect payment of duties.

Code of Federal Regulations, 2011 CFR

2011-10-01

... AUTHORITY GENERAL AGENT'S RESPONSIBILITY IN CONNECTION WITH FOREIGN REPAIR CUSTOM'S ENTRIES Sec. 5 General... section 3 of SRM-4 do not prevail, the General Agent shall effect payment of duties imposed by Customs and... cases, he shall refer the matter to the appropriate Coast Director for his (The Director) determination...

46 CFR Sec. 5 - General Agent's authority to effect payment of duties.

Code of Federal Regulations, 2010 CFR

2010-10-01

... AUTHORITY GENERAL AGENT'S RESPONSIBILITY IN CONNECTION WITH FOREIGN REPAIR CUSTOM'S ENTRIES Sec. 5 General... section 3 of SRM-4 do not prevail, the General Agent shall effect payment of duties imposed by Customs and... cases, he shall refer the matter to the appropriate Coast Director for his (The Director) determination...

46 CFR Sec. 5 - General Agent's authority to effect payment of duties.

Code of Federal Regulations, 2013 CFR

2013-10-01

... AUTHORITY GENERAL AGENT'S RESPONSIBILITY IN CONNECTION WITH FOREIGN REPAIR CUSTOM'S ENTRIES Sec. 5 General... section 3 of SRM-4 do not prevail, the General Agent shall effect payment of duties imposed by Customs and... cases, he shall refer the matter to the appropriate Coast Director for his (The Director) determination...

46 CFR Sec. 5 - General Agent's authority to effect payment of duties.

Code of Federal Regulations, 2014 CFR

2014-10-01

... AUTHORITY GENERAL AGENT'S RESPONSIBILITY IN CONNECTION WITH FOREIGN REPAIR CUSTOM'S ENTRIES Sec. 5 General... section 3 of SRM-4 do not prevail, the General Agent shall effect payment of duties imposed by Customs and... cases, he shall refer the matter to the appropriate Coast Director for his (The Director) determination...

77 FR 38856 - An Approach for Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-29

... discussion on defense-in-depth. Specifically, the SRM stated, Because the statements in Regulatory Guide 1... language to assure that the defense-in-depth philosophy is interpreted and implemented consistently. To the extent that other regulatory guidance refers to defense in depth, the relevant documents should be...

77 FR 29391 - An Approach for Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-17

... revise the discussion on defense-in-depth. Specifically, the SRM stated, Because the statements in... precise language to assure that the defense-in-depth philosophy is interpreted and implemented consistently. To the extent that other regulatory guidance refers to defense in depth, the relevant documents...

Analytical, experimental, and Monte Carlo system response matrix for pinhole SPECT reconstruction

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

Aguiar, Pablo, E-mail: pablo.aguiar.fernandez@sergas.es; Pino, Francisco; Silva-Rodríguez, Jesús

2014-03-15

Purpose: To assess the performance of two approaches to the system response matrix (SRM) calculation in pinhole single photon emission computed tomography (SPECT) reconstruction. Methods: Evaluation was performed using experimental data from a low magnification pinhole SPECT system that consisted of a rotating flat detector with a monolithic scintillator crystal. The SRM was computed following two approaches, which were based on Monte Carlo simulations (MC-SRM) and analytical techniques in combination with an experimental characterization (AE-SRM). The spatial response of the system, obtained by using the two approaches, was compared with experimental data. The effect of the MC-SRM and AE-SRM approachesmore » on the reconstructed image was assessed in terms of image contrast, signal-to-noise ratio, image quality, and spatial resolution. To this end, acquisitions were carried out using a hot cylinder phantom (consisting of five fillable rods with diameters of 5, 4, 3, 2, and 1 mm and a uniform cylindrical chamber) and a custom-made Derenzo phantom, with center-to-center distances between adjacent rods of 1.5, 2.0, and 3.0 mm. Results: Good agreement was found for the spatial response of the system between measured data and results derived from MC-SRM and AE-SRM. Only minor differences for point sources at distances smaller than the radius of rotation and large incidence angles were found. Assessment of the effect on the reconstructed image showed a similar contrast for both approaches, with values higher than 0.9 for rod diameters greater than 1 mm and higher than 0.8 for rod diameter of 1 mm. The comparison in terms of image quality showed that all rods in the different sections of a custom-made Derenzo phantom could be distinguished. The spatial resolution (FWHM) was 0.7 mm at iteration 100 using both approaches. The SNR was lower for reconstructed images using MC-SRM than for those reconstructed using AE-SRM, indicating that AE-SRM deals better with the projection noise than MC-SRM. Conclusions: The authors' findings show that both approaches provide good solutions to the problem of calculating the SRM in pinhole SPECT reconstruction. The AE-SRM was faster to create and handle the projection noise better than MC-SRM. Nevertheless, the AE-SRM required a tedious experimental characterization of the intrinsic detector response. Creation of the MC-SRM required longer computation time and handled the projection noise worse than the AE-SRM. Nevertheless, the MC-SRM inherently incorporates extensive modeling of the system and therefore experimental characterization was not required.« less

Ablation characteristics and reaction mechanism of insulation materials under slag deposition condition

NASA Astrophysics Data System (ADS)

Guan, Yiwen; Li, Jiang; Liu, Yang

2017-07-01

Current understanding of the physical and chemical processes involved in the ablation of insulation materials by highly aluminized solid propellants is limited. The study on the heat transfer and ablation principle of ethylene propylene diene monomer (EPDM) materials under slag deposition condition is essential for future design or modification of large solid rocket motors (SRMs) for launch application. In this paper, the alumina liquid flow pattern and the deposition principle in full-scale SRM engines are discussed. The interaction mechanism between the alumina droplets and the wall are analyzed. Then, an experimental method was developed to simulate the insulation material ablation under slag deposition condition. Experimental study was conducted based on a laboratory-scale device. Meanwhile, from the analysis of the cross-sectional morphology and chemical composition of the charring layer after ablation, the reaction mechanism of the charring layer under deposition condition was discussed, and the main reaction equation was derived. The numerical simulation and experimental results show the following. (i) The alumina droplet flow in the deposition section of the laboratory-scale device is similar to that of a full-scale SRM. (ii) The charring layer of the EPDM insulator displays a porous tight/loose structure under high-temperature slag deposition condition. (iii) A seven-step carbothermal reduction in the alumina is derived and established under high-pressure and high-temperature environment in the SRM combustion chamber. (iv) The analysis using thermodynamic software indicates that the reaction of the alumina and charring layer initially forms Al4C3 during the operation. Then, Al element and Al2OC compound are subsequently produced with the reduction in the release of gas CO as well with continuous environmental heating.

Striking against bioterrorism with advanced proteomics and reference methods.

PubMed

Armengaud, Jean

2017-01-01

The intentional use by terrorists of biological toxins as weapons has been of great concern for many years. Among the numerous toxins produced by plants, animals, algae, fungi, and bacteria, ricin is one of the most scrutinized by the media because it has already been used in biocrimes and acts of bioterrorism. Improving the analytical toolbox of national authorities to monitor these potential bioweapons all at once is of the utmost interest. MS/MS allows their absolute quantitation and exhibits advantageous sensitivity, discriminative power, multiplexing possibilities, and speed. In this issue of Proteomics, Gilquin et al. (Proteomics 2017, 17, 1600357) present a robust multiplex assay to quantify a set of eight toxins in the presence of a complex food matrix. This MS/MS reference method is based on scheduled SRM and high-quality standards consisting of isotopically labeled versions of these toxins. Their results demonstrate robust reliability based on rather loose scheduling of SRM transitions and good sensitivity for the eight toxins, lower than their oral median lethal doses. In the face of an increased threat from terrorism, relevant reference assays based on advanced proteomics and high-quality companion toxin standards are reliable and firm answers. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation of Platinum from Palladium and Iridium in Iron Meteorites and Accurate High-Precision Determination of Platinum Isotopes by Multi-Collector ICP-MS.

PubMed

Hunt, Alison C; Ek, Mattias; Schönbächler, Maria

2017-12-01

This study presents a new measurement procedure for the isolation of Pt from iron meteorite samples. The method also allows for the separation of Pd from the same sample aliquot. The separation entails a two-stage anion-exchange procedure. In the first stage, Pt and Pd are separated from each other and from major matrix constituents including Fe and Ni. In the second stage, Ir is reduced with ascorbic acid and eluted from the column before Pt collection. Platinum yields for the total procedure were typically 50-70%. After purification, high-precision Pt isotope determinations were performed by multi-collector ICP-MS. The precision of the new method was assessed using the IIAB iron meteorite North Chile. Replicate analyses of multiple digestions of this material yielded an intermediate precision for the measurement results of 0.73 for ε 192 Pt, 0.15 for ε 194 Pt and 0.09 for ε 196 Pt (2 standard deviations). The NIST SRM 3140 Pt solution reference material was passed through the measurement procedure and yielded an isotopic composition that is identical to the unprocessed Pt reference material. This indicates that the new technique is unbiased within the limit of the estimated uncertainties. Data for three iron meteorites support that Pt isotope variations in these samples are due to exposure to galactic cosmic rays in space.

Quarry waste management and recovery: first results connected to Carrara marble ravaneti (Italy)

NASA Astrophysics Data System (ADS)

Antonella Dino, Giovanna; Chiappino, Claudia; Rossetti, Piergiorgio

2017-04-01

Quarry waste (QW) represents a huge economic and environmental issue, due to loss of resources and to economic and environmental costs connected to waste management and landfilling activities. In many cases, valuable Raw Materials (RM) and Secondary Raw Materials (SRM) can be supplied by enhancing the QW recovery. In Italy large amounts of QW have been and still are dumped: such materials, if their quality (chemical, mineralogical, physical characteristics) and quantity are adequate, and if the impacts connected to their management are positive, can represent a valuable resource for SRM exploitation. Several dimension stone quarries have been and are interested by researches as for QW exploitation. Some researches show positive results, which are the basis for QW recovery (both from waste streams and from quarry dumps exploitation): a noticeable example is represented by Carrara marble waste. The Carrara quarry basin is characterized by ca. one hundred quarries for colored and white marble exploitation. The waste production can be summarized in: 80 Mm3 waste present in old quarry dumps (Ravaneti) and 3 Mm3/y of waste stream from quarrying activities. At present only 0.5 Mm3/y of QW is exploited for SRM production, causing a huge loss of resource. This has been the background for a preliminary research, on Carrara marble Ravaneti characterization, which was carried out thanks to the close cooperation between University of Torino, Società Apuana Marmi srl, and SET srl. In 2015, two QW dumping areas, Calocara and Lorano, were selected as representative for sampling activities. Three main sample categories were individuated based on granulometry (0.5-4 mm, 0-25 mm, 0-150 mm) to be characterized (size distribution, density, Atterberg limits, Los Angeles test, freezing and heat tests, flat and shape indexes, geochemistry, mineralogy). The results obtained are promising: the physical characterization shows an attitude for Carrara QW to be recovered as crushed materials for embankments and armour stone. Furthermore, the mineralogical and geochemical analyses show that these materials, being composed of nearly pure CaCO3, could find a proper application in high value products, as filler for paper, rubber, paint, plastic, etc. These data need to be confirmed by other analyses, thus a systematic characterization of QW present in the different quarry dumps is going to be programmed. R&D is strategic to solve problems connected to QW and landscape management. The cooperation between private Companies, Research Centers and Local Authorities is fundamental to reach the target, in terms of experimentation of new products (for civil works and infrastructure, building industry, agronomy, high-tech, etc.). Furthermore, if the stone industry aims at guaranteeing the systematic and convenient SRM recovery from QW, a change in exploitation and working activities has to be planned (eg. selection of the potential SRMs; dedicated stock areas for selected SRM; proper treatments depending on the kinds of reuse; treatment-activity protocols to produce each new product, etc.).

Self-regulation method: psychological, physiological and clinical considerations. An overview.

PubMed

Ikemi, A; Tomita, S; Kuroda, M; Hayashida, Y; Ikemi, Y

1986-01-01

Body-oriented therapies as relaxation training and certain forms of meditation are gaining popularity in the treatment and prevention of psychosomatic disorders. In this paper, a new method of self-control called self-regulation method (SRM), derived from autogenic training and Zen meditation, is presented. The technique of SRM is introduced. Secondly, physiological studies on SRM using skin temperature, galvanic skin response, and cortical evoked potentials are presented. Thirdly, the results of psychological tests conducted on SRM are presented. These psycho-physiological studies suggest that SRM may elicit a state of 'relaxed alertness'. Fourthly, clinical applications of SRM are discussed, and 3 cases are presented. Finally, SRM is discussed in relation to the psychology and physiology of 'relaxed alertness'.

NBL CRM 112-A: A new certified isotopic composition

NASA Astrophysics Data System (ADS)

Thomas, R. B.; Essex, R. M.; Mason, P.

2007-12-01

NBL CRM 112-A Uranium Metal Assay Standard is commonly used as a natural uranium isotopic reference material within the earth science mass spectrometry community. The metal is from the same parent material as NBS SRM 960, the uranyl nitrate solution, CRM 145, and the high-purity uranyl nitrate solution CRM 145-B. Because CRM 112-A has not yet been certified for isotopic composition, it has been assumed that this material has a natural 235U/238U (0.0072527), and the δ234U has been determined by measurement (e.g. -37.1‰; Cheng et al., 2000). These values have been widely used to calibrate the concentration of spikes and standards, and to correct measurements for instrument or mass bias. New, preliminary, isotopic measurements on CRM 145 and CRM 112-A performed at New Brunswick Laboratory suggest that these reference materials have a slightly lower 235U/238U and δ234U than have been commonly used. If this is the case, then data using the accepted values may be slightly biased. The significance of this bias will depend on the uncertainty of the measurement, how the CRM 112-A data is used to correct measurement data, the cited values that were used to correct the data, and the final certified values of the CRM. This fall, New Brunswick Laboratory is certifying the isotopic composition of the CRM 112-A metal using high precision thermal ionization mass spectrometry techniques. Upon completion of certification, the new CRM 112- A standard with certified isotopic ratios will provide the earth science community with a well characterized and traceable reference for calibrating and correcting their mass spectrometry measurement systems.

Large strain detection of SRM composite shell based on fiber Bragg grating sensor

NASA Astrophysics Data System (ADS)

Zhang, Lei; Chang, Xinlong; Zhang, Youhong; Yang, Fan

2017-12-01

There may be more than 2% strain of carbon fiber composite material on solid rocket motor (SRM) in some extreme cases. A surface-bonded silica fiber Bragg grating (FBG) strain sensor coated by polymer is designed to detect the large strain of composite material. The strain transfer relation of the FBG large strain sensor is deduced, and the strain transfer mechanism is verified by finite element simulation. To calibrate the sensors, the tensile test is done by using the carbon fiber composite plate specimen attached to the designed strain sensor. The results show that the designed sensor can detect the strain more than 3%, the strain sensitivity is 0.0762 pm/μɛ, the resolution is 13.13μɛ, and the fitting degree of the wavelength-strain curve fitting function is 0.9988. The accuracy and linearity of the sensor can meet the engineering requirements.

Optimization of fly ash as sand replacement materials (SRM) in cement composites containing coconut fiber

NASA Astrophysics Data System (ADS)

Nadzri, N. I. M.; Jamaludin, S. B.; Mazlee, M. N.; Jamal, Z. A. Z.

2016-07-01

The need of utilizing industrial and agricultural wastes is very important to maintain sustainability. These wastes are often incorporated with cement composites to improve performances in term of physical and mechanical properties. This study presents the results of the investigation of the response of cement composites containing coconut fiber as reinforcement and fly ash use as substitution of sand at different hardening days. Hardening periods of time (7, 14 and 28 days) were selected to study the properties of cement composites. Optimization result showed that 20 wt. % of fly ash (FA) is a suitable material for sand replacement (SRM). Meanwhile 14 days of hardening period gave highest compressive strength (70.12 MPa) from the cement composite containing 9 wt. % of coconut fiber and fly ash. This strength was comparable with the cement without coconut fiber (74.19 MPa) after 28 days of curing.

Finite element method for viscoelastic medium with damage and the application to structural analysis of solid rocket motor grain

NASA Astrophysics Data System (ADS)

Deng, Bin; Shen, ZhiBin; Duan, JingBo; Tang, GuoJin

2014-05-01

This paper studies the damage-viscoelastic behavior of composite solid propellants of solid rocket motors (SRM). Based on viscoelastic theories and strain equivalent hypothesis in damage mechanics, a three-dimensional (3-D) nonlinear viscoelastic constitutive model incorporating with damage is developed. The resulting viscoelastic constitutive equations are numerically discretized by integration algorithm, and a stress-updating method is presented by solving nonlinear equations according to the Newton-Raphson method. A material subroutine of stress-updating is made up and embedded into commercial code of Abaqus. The material subroutine is validated through typical examples. Our results indicate that the finite element results are in good agreement with the analytical ones and have high accuracy, and the suggested method and designed subroutine are efficient and can be further applied to damage-coupling structural analysis of practical SRM grain.

Line drawing of anomaly discovered in redesigned shuttle motor nozzle

NASA Technical Reports Server (NTRS)

1987-01-01

Line drawing titled 'DM-9 Case-to-Nozzle Joint' shows anomaly discovered in redesigned shuttle motor nozzle. The second full-duration test firing of NASA's redesigned Space Shuttle solid rocket motor (SRM), designated DM-9, was conducted 12-23-87 at Morton Thiokol's Wasatch facility in Utah. A post-test examination of the motor has revealed an anomaly in one nozzle component. Material was discovered missing from the nozzle outer boot ring, a large carbon phenolic composite ring used to anchor one end of the flexible boot that allows the nozzle to move and 'steer' the vehicle. About one-third of the missing 160 degrees of missing ring material was found adjacent to the forward nozzle section inside the motor. This diagram shows the location of the nozzle joint on an assembled SRM, and points out the shaded location of the outer boot ring that circles the motor within the nozzle joint.

Forensic discrimination of three common brands of kitchen knives in China by ICP-AES and infrared absorption.

PubMed

Bai, Ru-feng; Ma, Shu-hua; Zhang, Hai-dong; Chang, Lin; Zhang, Zhong; Liu, Li; Zhang, Feng-qin; Guo, Zhao-ming; Shi, Mei-sen

2014-03-01

A block of an injury instrument will be left in wounds sometimes, and the suspect instrument can be discriminated by comparison with the block that was left through elemental analysis. In this study, three brands (Shibazi, Zhangxiaoquan, Qiaoxifu) of kitchen knives with forged, chop, and slice application series were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and Infrared Absorption to investigate the type, number of elements and the reference range used for comparing. The results show that when regarding one or more element as the discriminative threshold, together with 5% relative standard deviation (RSD) as the reference range, all the samples could be distinguished among different series. Furthermore, within the same series, the discriminative capability could reach up to 88.57% for all samples. In addition, elements with high content, such as Cr, Mn, and C, were useful to discriminate among different series, and trace elements, such as Ni, Si, and Cu, were useful within the same series. However, in practice, it is necessary to evaluate the accuracy of the method by Standard Reference Material (SRM) before an examination is performed.

Comparison of a portable micro-X-ray fluorescence spectrometry with inductively coupled plasma atomic emission spectrometry for the ancient ceramics analysis

NASA Astrophysics Data System (ADS)

Papadopoulou, D. N.; Zachariadis, G. A.; Anthemidis, A. N.; Tsirliganis, N. C.; Stratis, J. A.

2004-12-01

Two multielement instrumental methods of analysis, micro X-ray fluorescence spectrometry (micro-XRF) and inductively coupled plasma atomic emission spectrometry (ICP-AES) were applied for the analysis of 7th and 5th century B.C. ancient ceramic sherds in order to evaluate the above two methods and to assess the potential to use the current compact and portable micro-XRF instrument for the in situ analysis of ancient ceramics. The distinguishing factor of interest is that micro-XRF spectrometry offers the possibility of a nondestructive analysis, an aspect of primary importance in the compositional analysis of cultural objects. Micro-XRF measurements were performed firstly directly on the ceramic sherds with no special pretreatment apart from surface cleaning (micro-XRF on sherds) and secondly on pressed pellet disks which were prepared for each ceramic sherd (micro-XRF on pellet). For the ICP-AES determination of elements, test solutions were prepared by the application of a microwave-assisted decomposition procedure in closed high-pressure PFA vessels. Also, the standard reference material SARM 69 was used for the efficiency calibration of the micro-XRF instrument and was analysed by both methods. In order to verify the calibration, the standard reference materials NCS DC 73332 and SRM620 as well as the reference materials AWI-1 and PRI-1 were analysed by micro-XRF. Elemental concentrations determined by the three analytical procedures (ICP-AES, micro-XRF on sherds and micro-XRF on pellets) were statistically treated by correlation analysis and Student's t-test (at the 95% confidence level).

BSE situation and establishment of Food Safety Commission in Japan

PubMed Central

Kim, Chi-Kyeong

2006-01-01

Eight major policies were implemented by Japanese Government since Oct. 2001, to deal with bovine spongiform encephalopathy (BSE). These are; 1) Surveillance in farm by veterinarian, 2) Prion test at healthy 1.3mi cows/yr, by veterinarian, 3) Elimination of specified risk material (SRM), 4) Ban of MBM for production, sale use, 5) Prion test for fallen stocks, 6) Transparent information and traceability, 7) New Measures such as Food Safety Basic Law, and 8) Establish of Food Safety Commission in the Cabinet Office. At this moment, the extent of SRM risk has only been indicated by several reports employing tests with a limited sensitivity. There is still a possibility that the items in the SRM list will increase in the future, and this indiscriminately applies to Japanese cattle as well. Although current practices of SRM elimination partially guarantee total food safety, additional latent problems and imminent issues remain as potential headaches to be addressed. If the index of SRM elimination cannot guarantee reliable food safety, we have but to resort to total elimination of tissues from high risk-bearing and BSE-infected animals. However, current BSE tests have their limitations and can not yet completely detect high-risk and/or infected animals. Under such circumstances, tissues/wastes and remains of diseased, affected fallen stocks and cohort animals have to be eliminated to prevent BSE invading the human food chain systems. The failure to detect any cohort should never be allowed to occur, and with regular and persistent updating of available stringent records, we are at least adopting the correct and useful approach as a reawakening strategy to securing food safety. In this perspective, traceability based on a National Identification System is required. PMID:16434842

Microwave digestion preparation and ICP determination of boron in human plasma

NASA Technical Reports Server (NTRS)

Ferrando, A. A.; Green, N. R.; Barnes, K. W.; Woodward, B.

1993-01-01

A microwave digestion procedure, followed by Inductively Coupled Argon Plasma Spectroscopy, is described for the determination of boron (B) in human plasma. The National Institute of Standards and Technology (NIST) currently does not certify the concentration of B in any substance. The NIST citrus leaves 1572 (CL) Standard Reference Material (SRM) and wheat flour 1567a (WF) were chosen to determine the efficacy of digestion. CL and WF values compare favorably to those obtained from an open-vessel, wet digestion followed by ICP, and by neutron activation and mass spectrometric measurements. Plasma samples were oxidized by doubled-distilled ultrapure HNO3 in 120 mL PFA Teflon vessels. An MDS-81D microwave digestion procedure allows for rapid and relatively precise determination of B in human plasma, while limiting handling hazards and sources of contamination.

Multielemental analysis in small amounts of environmental reference materials with inductively coupled plasma mass spectrometry.

PubMed

Dombovári, J; Becker, J S; Dietze, H J

2000-07-01

The lowest possible sample weight for performing multielemental trace element analysis on environmental and biological samples by ICP-MS has been investigated. The certified reference materials Bovine Liver NIST SRM 1577b, Human Hair NCS DC 73347 and Oriental Tobacco Leaves CTA-OTL-1 were applied at sample weights (1, 5, 20 and 50 mg aliquots, n = 10) which were significantly lower than those recommended with most recoveries in the range of 95-110%. Samples were digested in a mixture of nitric acid, hydrogen peroxide and hydrogen fluoride by closed-vessel microwave digestion. Multielemental analysis was performed with an optimized ICP-QMS method. Aqueous standard solutions were applied for external calibration with rhodium as the internal standard element. The detection limits varied between 0.02-0.38 microg/g for Li, Na, Cr, Mn, Ni, Cu, Zn, Sr, Cd, Ba and Pb, and up to 1.92 microg/g for Mg, Al, Ca, Fe and Ni. Digested human plasma samples were spiked with multielemental solution (0.5-10 microg/L) to test the analytical method and the recoveries were 95-105% for most analytes. Our results show that in the case of homogeneous SRMs it is possible to use them in very low amounts (1-5 mg) for method development and quality control.

The Solid Rocket Motor Slag Population: Results of a Radar-Based Regressive Statistical Evaluation

NASA Technical Reports Server (NTRS)

Horstman, Matthew F.; Xu, Yu-Lin

2008-01-01

Solid rocket motor (SRM) slag has been identified as a potential source of man-made orbital debris. The possibility that SRMs (in addition to generating dust particles in the sub-millimeter range) may generate particles up to centimeters in size has caused concern regarding their contribution to the debris environment. Returned surfaces from space do not have sufficient area or exposure time to provide a clear picture of the SRM millimeter and centimeter debris population. Currently, radar observation is probably the only way to collect data showing the debris contribution from SRMs. Such observation is used to sample the debris environment, but it is difficult to obtain accurate orbital elements for the detected debris objects. NASA has developed several models to describe the different orbital debris populations, based on assumed debris production mechanisms to create clouds of debris objects that can be propagated in time. The NASA model, LEGEND (LEO-to-GEO Environment Debris), functions as a time-tested debris model for most debris sources. However, the current LEGEND model does not include contributions from the SRM population. An SRM model has recently been developed by NASA, based on purely theoretical details of SRM production and known SRM launches, but verification with hard data is needed. Because the detections of individual SRM objects cannot be deterministically separated from the total debris observed by radar, the validation of the SRM model can only be done by combining it with the LEGEND breakup model and comparing it with data. By applying observational constraints, the degree of SRM slag contribution to the environment may be estimated. This serves as an observationally sound method from which to calibrate a purely theoretical model into something more realistic. For this study, we use the populations observed by the Haystack radar from 1996 to present. For the SRM debris, we use a historical database of SRM launches, propellant masses, and estimated locations and times of tailoff to produce and propagate the SRM debris clouds. Comparisons with radar data from the ensuing years were made, and the SRM model was altered with respect to size and mass production of slag particles to reflect the populations estimated from the data. The result is a model SRM population that fits within the bounds of the observed environment and estimates of the production and contribution of SRM debris to the environment.

Determination of Chloride in Infant Formula and Adult/Pediatric Nutritional Formula by Potentiometric Titration: Single-Laboratory Validation, First Action 2015.07.

PubMed

Bolong, Wu; Fengxia, Zhang; Xiaoning, Ma; Fengjuan, Zhou; Brunelle, Sharon L

2016-01-01

A potentiometric method for determination of chloride was validated against AOAC Standard Method Performance Requirement (SMPR(®)) 2014.015. Ten AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) matrixes, including National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 1849a, were tested in duplicate on 6 independent days. The repeatability (RSDr) ranged from 0.43 to 1.34%, and the intermediate reproducibility (RSDiR) ranged from 0.80 to 3.04%. All results for NIST SRM 1849a were within the range of the certified concentration (701 ± 17 mg/100 g). Recovery was demonstrated with two overspike levels, 50 and 100%, in the 10 SPIFAN matrixes. Samples were tested in duplicate on 3 different days, and all results were within the SMPR requirement of 95 to 105%. The LOQs of the method for powdered products and ready-to-feed or reconstituted products were 20 mg/100 g and 2.2 mg/100 mL, respectively. A wide analytical range from the LOQ to 99.5% chlorine content can be reached with an appropriate dilution factor, but in practice, the upper analytical value observed in routine matrix testing was approximately 1080 mg/100 g in skim milk powder. This is a rapid, simple, and reliable chlorine-testing method applicable to infant formula, adult nutritionals, and ingredients used in these dairy-based products, such as skim milk powder, desalted whey powder, whey protein powder, and whole milk powder.

An interlaboratory comparison study on the measurement of elements in PM10

NASA Astrophysics Data System (ADS)

Yatkin, Sinan; Belis, Claudio A.; Gerboles, Michel; Calzolai, Giulia; Lucarelli, Franco; Cavalli, Fabrizia; Trzepla, Krystyna

2016-01-01

An inter-laboratory comparison study was conducted to measure elemental loadings on PM10 samples, collected in Ispra, a regional background/rural site in Italy, using three different XRF (X-ray Fluorescence) methods, namely Epsilon 5 by linear calibration, Quant'X by the standardless analysis, and PIXE (Particle Induced X-ray Emission) with linear calibration. A subset of samples was also analyzed by ICP-MS (Inductively Coupled Plasma-Mass Spectrometry). Several metrics including method detection limits (MDLs), precision, bias from a NIST standard reference material (SRM 2783) quoted values, relative absolute difference, orthogonal regression and the ratio of the absolute difference between the methods to claimed uncertainty were used to compare the laboratories. The MDLs were found to be comparable for many elements. Precision estimates were less than 10% for the majority of the elements. Absolute biases from SRM 2783 remained less than 20% for the majority of certified elements. The regression results of PM10 samples showed that the three XRF laboratories measured very similar mass loadings for S, K, Ti, Mn, Fe, Cu, Br, Sr and Pb with slopes within 20% of unity. The ICP-MS results confirmed the agreement and discrepancies between XRF laboratories for Al, K, Ca, Ti, V, Cu, Sr and Pb. The ICP-MS results are inconsistent with the XRF laboratories for Fe and Zn. The absolute differences between the XRF laboratories generally remained within their claimed uncertainties, showing a pattern generally consistent with the orthogonal regression results.

Certification of the Uranium Isotopic Ratios in Nbl Crm 112-A, Uranium Assay Standard (Invited)

NASA Astrophysics Data System (ADS)

Mathew, K. J.; Mason, P.; Narayanan, U.

2010-12-01

Isotopic reference materials are needed to validate measurement procedures and to calibrate multi-collector ion counting detector systems. New Brunswick Laboratory (NBL) provides a suite of certified isotopic and assay standards for the US and international nuclear safeguards community. NBL Certified Reference Material (CRM) 112-A Uranium Metal Assay Standard with a consensus value of 137.88 for the 238U/235U ratio [National Bureau of Standards -- NBS, currently named National Institute for Standards and Technology, Standard Reference Material (SRM) 960 had been renamed CRM 112-A] is commonly used as a natural uranium isotopic reference material within the earth science community. We have completed the analytical work for characterizing the isotopic composition of NBL CRM 112-A Uranium Assay Standard and NBL CRM 145 (uranyl nitrate solution prepared from CRM 112-A). The 235U/238U isotopic ratios were characterized using the total evaporation (TE) and the modified total evaporation (MTE) methods. The 234U/238U isotope ratios were characterized using a conventional analysis technique and verified using the ratios measured in the MTE analytical technique. The analysis plan for the characterization work was developed such that isotopic ratios that are traceable to NBL CRM U030-A are obtained. NBL is preparing a certificate of Analysis and will issue a certificate for Uranium Assay and Isotopics. The results of the CRM 112-A certification measurements will be discussed. These results will be compared with the average values from Richter et al (2010). A comparison of the precision and accuracy of the measurement methods (TE, MTE and Conventional) employed in the certification will be presented. The uncertainties in the 235U/238U and 234U/238U ratios, calculated according to the Guide to the Expression of Uncertainty in Measurements (GUM) and the dominant contributors to the combined standard uncertainty will be discussed.

Strategic effects of future environmental policy commitments: climate change, solar radiation management and correlated air pollutants.

PubMed

Qu, Jingwen; Silva, Emilson Caputo Delfino

2015-03-15

We study the effects of environmental policy commitments in a futuristic world in which solar radiation management (SRM) can be utilized to reduce climate change damages. Carbon and sulfur dioxide emissions (correlated pollutants) can be reduced through tradable permits. We show that if nations simultaneously commit to carbon permit policies, national SRM levels rise with carbon quotas. Alternatively, if they simultaneously commit to SRM policies, the global temperature falls with each unit increase in the global SRM level. A nation always wishes to be a leader in policymaking, but prefers carbon to SRM policymaking. The globe prefers SRM policy commitments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Core Sulphate-Reducing Microorganisms in Metal-Removing Semi-Passive Biochemical Reactors and the Co-Occurrence of Methanogens

PubMed Central

Rezadehbashi, Maryam; Baldwin, Susan A.

2018-01-01

Biochemical reactors (BCRs) based on the stimulation of sulphate-reducing microorganisms (SRM) are emerging semi-passive remediation technologies for treatment of mine-influenced water. Their successful removal of metals and sulphate has been proven at the pilot-scale, but little is known about the types of SRM that grow in these systems and whether they are diverse or restricted to particular phylogenetic or taxonomic groups. A phylogenetic study of four established pilot-scale BCRs on three different mine sites compared the diversity of SRM growing in them. The mine sites were geographically distant from each other, nevertheless the BCRs selected for similar SRM types. Clostridia SRM related to Desulfosporosinus spp. known to be tolerant to high concentrations of copper were members of the core microbial community. Members of the SRM family Desulfobacteraceae were dominant, particularly those related to Desulfatirhabdium butyrativorans. Methanogens were dominant archaea and possibly were present at higher relative abundances than SRM in some BCRs. Both hydrogenotrophic and acetoclastic types were present. There were no strong negative or positive co-occurrence correlations of methanogen and SRM taxa. Knowing which SRM inhabit successfully operating BCRs allows practitioners to target these phylogenetic groups when selecting inoculum for future operations. PMID:29473875

Five solar geoengineering tropes that have outstayed their welcome

NASA Astrophysics Data System (ADS)

Reynolds, Jesse L.; Parker, Andy; Irvine, Peter

2016-12-01

In the last decade, solar geoengineering (solar radiation management, or SRM) has received increasing consideration as a potential means to reduce risks of anthropogenic climate change. Some ideas regarding SRM that have been proposed have receded after being appropriately scrutinized, while others have strengthened through testing and critique. This process has improved the understanding of SRM's potential and limitations. However, several claims are frequently made in the academic and popular SRM discourses and, despite evidence to the contrary, pose the risk of hardening into accepted facts. Here, in order to foster a more productive and honest debate, we identify, describe, and refute five of the most problematic claims that are unsupported by existing evidence, unlikely to occur, or greatly exaggerated. These are: (A) once started, SRM cannot be stopped; (B) SRM is a right-wing project; (C) SRM would cost only a few billion dollars per year; (D) modeling studies indicate that SRM would disrupt monsoon precipitation; and (E) there is an international prohibition on outdoors research. SRM is a controversial proposed set of technologies that could prove to be very helpful or very harmful, and it warrants vigorous and informed public debate. By highlighting and debunking some persistent but unsupported claims, this paper hopes to bring rigor to such discussions.

Evaluation of SRM flex bearing materials and processes

NASA Technical Reports Server (NTRS)

Wood, T. E.

1980-01-01

Tensile, peel, and shear testing was performed on combinations of primers, adhesives, tycements and rubber compounds cured at various times and temperatures. The materials used in the fabrication of the solid rocket motor flex bearing as well as in other systems were evaluated. A compatibility study between adhesives and tycements was initiated. The flex bearing mold design was reviewed by our tooling experts.

Development of an SRM method for absolute quantitation of MYDGF/C19orf10 protein.

PubMed

Dwivedi, Ravi C; Krokhin, Oleg V; El-Gabalawy, Hani S; Wilkins, John A

2016-06-01

To develop a MS-based selected reaction monitoring (SRM) assay for quantitation of myeloid-derived growth factor (MYDGF) formerly chromosome 19 open reading frame (C19orf10). Candidate reporter peptides were identified in digests of recombinant MYDGF. Isotopically labeled forms of these reporter peptides were employed as internal standards for assay development. Two reference peptides were selected SYLYFQTFFK and GAEIEYAMAYSK with respective LOQ of 42 and 380 attomole per injection. Application of the assay to human serum and synovial fluid determined that the assay sensitivity was reduced and quantitation was not achievable. However, the partial depletion of albumin and immunoglobulin from synovial fluids provided estimates of 300-650 femtomoles per injection (0.7-1.6 nanomolar (nM) fluid concentrations) in three of the six samples analyzed. A validated sensitive assay for the quantitation of MYDGF in biological fluids was developed. However, the endogenous levels of MYDGF in such fluids are at or below the current levels of quantitation. The levels of MYDGF are lower than those previously reported using an ELISA. The current results suggest that additional steps may be required to remove high abundance proteins or to enrich MYDGF for SRM-based quantitation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Test stand for Titan 34D SRM static firing

NASA Technical Reports Server (NTRS)

Glozman, Vladimir; Shipway, George

1988-01-01

An existing liquid engine test stand at the AF Astronautics Laboratory was refurbished and extensively modified to accommodate the static firing of the Titan 34D solid rocket motor (SRM) in the vertical nozzle down orientation. The main load restraint structure was designed and built to secure the SRM from lifting off during the firing. In addition, the structure provided weather protection, temperature conditioning of the SRM, and positioning of the measurement and recording equipment. The structure was also used for stacking/de-stacking of SRM segments and other technological processes. The existing stand, its foundation and anchorage were thoroughly examined and reanalyzed. Necessary stand modifications were carried out to comply with the requirements of the Titan 34D SRM static firing.

SRM-Assisted Trajectory for the GTX Reference Vehicle

NASA Technical Reports Server (NTRS)

Riehl, John; Trefny, Charles; Kosareo, Daniel

2002-01-01

A goal of the GTX effort has been to demonstrate the feasibility of a single stage- to- orbit (SSTO) vehicle that delivers a small payload to low earth orbit. The small payload class was chosen in order to minimize the risk and cost of development of this revolutionary system. A preliminary design study by the GTX team has resulted in the current configuration that offers considerable promise for meeting the stated goal. The size and gross lift-off weight resulting from scaling the current design to closure however may be considered impractical for the small payload. In lieu of evolving the project's reference vehicle to a large-payload class, this paper offers the alternative of using solid-rocket motors in order to close the vehicle at a practical scale. This approach offers a near-term, quasi-reusable system that easily evolves to reusable SSTO following subsequent development and optimization. This paper presents an overview of the impact of the addition of SRM's to the GTX reference vehicle's performance and trajectory. The overall methods of vehicle modeling and trajectory optimization will also be presented. A key element in the trajectory optimization is the use of the program OTIS 3.10 that provides rapid convergence and a great deal of flexibility to the user. This paper will also present the methods used to implement GTX requirements into OTIS modeling.

SRM-Assisted Trajectory for the GTX Reference Vehicle

NASA Technical Reports Server (NTRS)

Riehl, John; Trefny, Charles; Kosareo, Daniel (Technical Monitor)

2002-01-01

A goal of the GTX effort has been to demonstrate the feasibility of a single stage-to-orbit (SSTO) vehicle that delivers a small payload to low earth orbit. The small payload class was chosen in order to minimize the risk and cost of development of this revolutionary system. A preliminary design study by the GTX team has resulted in the current configuration that offers considerable promise for meeting the stated goal. The size and gross lift-off weight resulting from scaling the current design to closure however may be considered impractical for the small payload. In lieu of evolving the project' reference vehicle to a large-payload class, this paper offers the alternative of using solid-rocket motors in order to close the vehicle at a practical scale. This approach offers a near-term, quasi-reusable system that easily evolves to reusable SSTO following subsequent development and optimization. This paper presents an overview of the impact of the addition of SRM's to the GTX reference vehicle#s performance and trajectory. The overall methods of vehicle modeling and trajectory optimization will also be presented. A key element in the trajectory optimization is the use of the program OTIS 3.10 that provides rapid convergence and a great deal of flexibility to the user. This paper will also present the methods used to implement GTX requirements into OTIS modeling.

A workflow for multiclass determination of 256 pesticides in essential oils by liquid chromatography tandem mass spectrometry using evaporation and dilution approaches: Application to lavandin, lemon and cypress essential oils.

PubMed

Fillatre, Yoann; Rondeau, David; Daguin, Antoine; Communal, Pierre-Yves

2016-01-01

This paper describes the determination of 256 multiclass pesticides in cypress and lemon essential oils (EOs) by the way of liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS) analysis using the scheduled selected reaction monitoring mode (sSRM) available on a hybrid quadrupole linear ion trap (QLIT) mass spectrometer. The performance of a sample preparation of lemon and cypress EOs based on dilution or evaporation under nitrogen assisted by a controlled heating were assessed. The best limits of quantification (LOQs) were achieved with the evaporation under nitrogen method giving LOQs≤10µgL(-1) for 91% of the pesticides. In addition the very satisfactory results obtained for recovery, repeatability and linearity showed that for EOs of relatively low evaporation temperature, a sample preparation based on evaporation under nitrogen is well adapted and preferable to dilution. By compiling these results with those previously published by some of us on lavandin EO, we proposed a workflow dedicated to multiresidue determination of pesticides in various EOs by LC-ESI/sSRM. Among the steps involved in this workflow, the protocol related to mass spectrometry proposes an alternative confirmation method to the classical SRM ratio criteria based on a sSRM survey scan followed by an information-dependent acquisition using the sensitive enhanced product ion (EPI) scan to generate MS/MS spectra then compared to a reference. The submitted workflow was applied to the case of lemon EOs samples highlighting for the first time the simultaneous detection of 20 multiclass pesticides in one EO. Some pesticides showed very high concentration levels with amounts greatly exceeding the mgL(-1). Copyright © 2015 Elsevier B.V. All rights reserved.

Microbiological Horticultural Internship Final Abstract

NASA Technical Reports Server (NTRS)

Palmer, Shane R.; Spencer, Lashelle (Editor)

2017-01-01

GMO dwarf plum (Prunus domestica) is being evaluated as a candidate food crop for long duration space flight missions. A project was undertaken to develop a protocol for transferring selected genetic lines of GMO plum (previously maintained in pots and propagated by cuttings at NASA's Kennedy Space Center in Florida) into in vitro tissue culture. In vitro culture may reduce the space, materials, and labor required to maintain the current lines of GMO plum and better preserve them for future study. Fresh plant material from three selected GMO plum lines (NASA-5, NASA-10, and NASA-11) and a non-modified control line (Control-5) were processed aseptically into in vitro culture on four separate occasions. The impact of multiple treatments on the successful growth of GMO plum tissue in vitro were tested: Parent explant tissue type (leaf petioles, stem nodes containing buds and internodes without buds), tissue sterilization method [soaking in 10 bleach only (5 min for petioles or 10 min for nodesinternodes), or soaking in 70 EtOH (30 sec) followed by 10 bleach (5 min for petioles and 10 min for nodesinternodes)], and media type [three Murashige and Skoog-based medias (SGM, SRM, and SRM+2,4-D) and one recipe containing woody plant media (WPM)]. 22.2 of the plates containing tissue sterilized with bleach alone developed microbial contamination after two weeks, while only 11.8 of plates containing tissue sterilized sequentially with EtOH and bleach developed contamination. Node bud tissue from all four genetic lines of plum produced leafy plantlets on SGM and SRM media after 4-6 weeks. The most numerous and well-developed plantlets were present on SGM. Upon reaching suitable size, plantlets were transferred to larger media containers for further growth. Some node bud growth occurred on SRM+2,4-D and WPM 2.5 weeks after plating, however as of yet no pieces on SRM+2,4-D have adequate development for transferring. Tissue pieces from NASA-5 plated on WPM are developing leaves and will be ready for transferring soon. Petioles and internode tissue lacking bud meristem failed to produce any plantlets on any plates, however petioles developed large masses of undifferentiated callus tissue on SRM+2,4-D media. These callused pieces were then transferred to SRM+TDZ media, which resulted in even larger callus growth but no differentiation. All four selected plum lines were successfully transitioned into in vitro culture. Nodes from NASA-5 and NASA-10 lines produced the most numerous and well-developed leafy plantlets in vitro, while those from NASA-11 and Control-5 were generally smaller, slower growing and less numerous. The best method overall was to use young stem node tissue with buds, surface sterilize the pieces sequentially with 70 EtOH and 10 bleach, and then plate them onto SGM media. Future areas of study will include introducing additional genetic lines of GMO plum into in vitro culture, attempting to induce shoot growth in petiole callus tissue, testing methods (such as cold storage) that extend the time interval between transferring explants into new media, and testing viability of plantlets transferred from in vitro culture back to traditional pot culture.

Treatment of Solid Rocket Motors that Complies with Established Protocols to Ensure Planetary Protection

NASA Technical Reports Server (NTRS)

Stefanski, Philip L.; Soler-Luna, Adrian

2017-01-01

This presentation discusses recent work being conducted by the National Aeronautics and Space Administration (NASA) at Marshall Space Flight Center (MSFC) to evaluate various methods that could be employed to provide for planetary protection of those solar system bodies that are candidates for extraterrestrial life, thus preventing contamination of such bodies. MSFC is presently involved in the development phase of the Europa Lander De-Orbital Stage (DOS) braking motor. In order to prevent bio-contamination of this Jovian satellite, three paths are currently being considered. The first is (1) Bio-Reduction of those microscopic organisms in or on the vehicle (in this case a solid rocket motor (SRM)) that might otherwise be transported during the mission. Possible methods being investigated include heat sterilization, application or incorporation of biocide materials, and irradiation. While each method can be made to work, effects on the SRM's components (propellant, liner, insulation, etc.) could well prove deleterious. A second path would be use of (2) Bio-Barrier material(s). So long as such barrier(s) can maintain their integrity, planetary protection should be afforded. Under the harsh conditions encountered during extended spaceflight (vacuum, temperature extremes, radiation), however, such barrier(s) could well experience a breach. Finally, a third path would be to perform (3) Pyrotechnic Sterilization of the SRM during its end-of-mission phase. Multiple pyrotechnic units would be triggered to ensure activation of such an event and provide for a final sterilization before vehicle impact. In light of Europa's stringent bio-reduction targets, the final and best choice to minimize risk will probably be some combination of the above.

Multiple products monitoring as a robust approach for peptide quantification.

PubMed

Baek, Je-Hyun; Kim, Hokeun; Shin, Byunghee; Yu, Myeong-Hee

2009-07-01

Quantification of target peptides and proteins is crucial for biomarker discovery. Approaches such as selected reaction monitoring (SRM) and multiple reaction monitoring (MRM) rely on liquid chromatography and mass spectrometric analysis of defined peptide product ions. These methods are not very widespread because the determination of quantifiable product ion using either SRM or MRM is a very time-consuming process. We developed a novel approach for quantifying target peptides without such an arduous process of ion selection. This method is based on monitoring multiple product ions (multiple products monitoring: MpM) from full-range MS2 spectra of a target precursor. The MpM method uses a scoring system that considers both the absolute intensities of product ions and the similarities between the query MS2 spectrum and the reference MS2 spectrum of the target peptide. Compared with conventional approaches, MpM greatly improves sensitivity and selectivity of peptide quantification using an ion-trap mass spectrometer.

Public understanding of solar radiation management

NASA Astrophysics Data System (ADS)

Mercer, A. M.; Keith, D. W.; Sharp, J. D.

2011-10-01

We report the results of the first large-scale international survey of public perception of geoengineering and solar radiation management (SRM). Our sample of 3105 individuals in the United States, Canada and the United Kingdom was recruited by survey firms that administer internet surveys to nationally representative population samples. Measured familiarity was higher than expected, with 8% and 45% of the population correctly defining the terms geoengineering and climate engineering respectively. There was strong support for allowing the study of SRM. Support decreased and uncertainty rose as subjects were asked about their support for using SRM immediately, or to stop a climate emergency. Support for SRM is associated with optimism about scientific research, a valuing of SRM's benefits and a stronger belief that SRM is natural, while opposition is associated with an attitude that nature should not be manipulated in this way. The potential risks of SRM are important drivers of public perception with the most salient being damage to the ozone layer and unknown risks. SRM is a new technology and public opinions are just forming; thus all reported results are sensitive to changes in framing, future information on risks and benefits, and changes to context.

Development of inspection techniques for quantitatively measuring surface contamination on SRM hardware

NASA Technical Reports Server (NTRS)

Law, R. D.

1989-01-01

A contaminant is any material or substance which is potentially undesirable or which may adversely affect any part, component, or assembly. Contamination control of SRM hardware surfaces is a serious concern, for both Thiokol and NASA, with particular concern for contaminants which may adversely affect bonding surfaces. The purpose of this study is to develop laboratory analytical techniques which will make it possible to certify the cleanliness of any designated surface, with special focus on particulates (dust, dirt, lint, etc.), oils (hydrocarbons, silicones, plasticizers, etc.), and greases (HD-2, fluorocarbon grease, etc.). The hardware surfaces of concern will include D6AC steel, aluminum alloys, anodized aluminum alloys, glass/phenolic, carbon/phenolic, NBR/asbestos-silica, and EPDM rubber.

Standardization of proton-induced x-ray emission technique for analysis of thick samples

NASA Astrophysics Data System (ADS)

Ali, Shad; Zeb, Johar; Ahad, Abdul; Ahmad, Ishfaq; Haneef, M.; Akbar, Jehan

2015-09-01

This paper describes the standardization of the proton-induced x-ray emission (PIXE) technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard reference materials (SRMs) were analyzed using this technique and the data were compared with the already known data of these certified SRMs. These samples were selected in order to cover the maximum range of elements in the periodic table. Each sample was irradiated for three different values of collected beam charges at three different times. A proton beam of 2.57 MeV obtained using 5UDH-II Pelletron accelerator was used for excitation of x-rays from the sample. The acquired experimental data were analyzed using the GUPIXWIN software. The results show that the SRM data and the data obtained using the PIXE technique are in good agreement.

Method for characterization of low molecular weight organic acids in atmospheric aerosols using ion chromatography mass spectrometry.

PubMed

Brent, Lacey C; Reiner, Jessica L; Dickerson, Russell R; Sander, Lane C

2014-08-05

The structural composition of PM2.5 monitored in the atmosphere is usually divided by the analysis of organic carbon, black (also called elemental) carbon, and inorganic salts. The characterization of the chemical composition of aerosols represents a significant challenge to analysts, and studies are frequently limited to determination of aerosol bulk properties. To better understand the potential health effects and combined interactions of components in aerosols, a variety of measurement techniques for individual analytes in PM2.5 need to be implemented. The method developed here for the measurement of organic acids achieves class separation of aliphatic monoacids, aliphatic diacids, aromatic acids, and polyacids. The selective ion monitoring capability of a triple quadropole mass analyzer was frequently capable of overcoming instances of incomplete separations. Standard Reference Material (SRM) 1649b Urban Dust was characterized; 34 organic acids were qualitatively identified, and 6 organic acids were quantified.

Determination and distribution of rare earth elements in beach rock samples using instrumental neutron activation analysis (INAA)

NASA Astrophysics Data System (ADS)

Ravisankar, R.; Manikandan, E.; Dheenathayalu, M.; Rao, Brahmaji; Seshadreesan, N. P.; Nair, K. G. M.

2006-10-01

Beach rocks are a peculiar type of formation when compared to other types of rocks. Rare earth element (REE) concentrations in beach rock samples collected from the South East Coast of Tamilnadu, India, have been measured using the instrumental neutron activation analysis (INAA) single comparator K0 method. The irradiations were carried out using a thermal neutron flux of ˜10 11 n cm -2 s -1 at 20 kW power using the Kalpakkam mini reactor (KAMINI), IGCAR, Kalpakkam, Tamilnadu. Accuracy and precision were evaluated by assaying irradiated standard reference material (SRM 1646a estuarine sediment). The results being found to be in good agreement with certified values. REE elements have been determined from 15 samples using high-resolution gamma spectrometry. The geochemical behavior of REE in beach rock, in particular REE (chondrite-normalized) pattern has been studied.

A new method for stable lead isotope extraction from seawater.

PubMed

Zurbrick, Cheryl M; Gallon, Céline; Flegal, A Russell

2013-10-24

A new technique for stable lead (Pb) isotope extraction from seawater is established using Toyopearl AF-Chelate 650M(®) resin (Tosoh Bioscience LLC). This new method is advantageous because it is semi-automated and relatively fast; in addition it introduces a relatively low blank by minimizing the volume of chemicals used in the extraction. Subsequent analyses by HR ICP-MS have a good relative external precision (2σ) of 3.5‰ for (206)Pb/(207)Pb, while analyses by MC-ICP-MS have a better relative external precision of 0.6‰. However, Pb sample concentrations limit MC-ICP-MS analyses to (206)Pb, (207)Pb, and (208)Pb. The method was validated by processing the common Pb isotope reference material NIST SRM-981 and several GEOTRACES intercalibration samples, followed by analyses by HR ICP-MS, all of which showed good agreement with previously reported values. Copyright © 2013 Elsevier B.V. All rights reserved.

Responsiveness of the WOMAC osteoarthritis index as compared with the SF-36 in patients with osteoarthritis of the legs undergoing a comprehensive rehabilitation intervention

PubMed Central

Angst, F; Aeschlimann, A; Steiner, W; Stucki, G

2001-01-01

OBJECTIVE—To compare the responsiveness of the condition-specific Western Ontario and McMaster Universities osteoarthritis (OA) index (WOMAC) and the generic Short Form-36 (SF-36) in patients with OA of the legs undergoing a comprehensive inpatient rehabilitation intervention.
METHODS—A prospective follow up study of consecutively referred inpatients of a rehabilitation clinic was made. The patients included fulfilled the American College of Rheumatology criteria for knee or hip OA and underwent both passive and, particularly, active physical therapy for three to four weeks. Responsiveness assessment was performed using the standardised response mean (SRM), effect size, and Guyatt's responsiveness statistic between admission and discharge (end of rehabilitation) and then again between admission and three months later. For pain and function the SRMs were stratified by sex and OA joint. Effects were tested by the t test and SRMs of different scales were compared by the jack knife test.
RESULTS—At the three month follow up, complete data were obtained for 223 patients. In general, the three responsiveness statistics showed a similar order of responsiveness. For both instruments, the pain scales were more responsive than the function scales. The responsiveness of the pain scale of both instruments was comparable (SRM=0.723 for WOMAC and SRM=0.528 for SF-36 at the end of rehabilitation; SRM=0.377 for WOMAC and SRM=0.468 for SF-36 at the three month follow up). In the measurement of function, the WOMAC was significantly more responsive than the SF-36 (SRMs, end of rehabilitation: 0.628 v 0.249; three month follow up: 0.235 v −0.001). Responsiveness tended to be higher in women and in knee OA than in men and hip OA.
CONCLUSIONS—Both instruments, the WOMAC and the SF-36, capture improvement in pain in patients undergoing comprehensive inpatient rehabilitation intervention. Functional improvement can be detected better by the WOMAC than by the SF-36. All the other scales of both instruments were more weakly responsive.

 PMID:11502609

Targeted quantification of low ng/mL level proteins in human serum without immunoaffinity depletion

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

Shi, Tujin; Sun, Xuefei; Gao, Yuqian

2013-07-05

We recently reported an antibody-free targeted protein quantification strategy, termed high-pressure, high-resolution separations with intelligent selection and multiplexing (PRISM) for achieving significantly enhanced sensitivity using selected reaction monitoring (SRM) mass spectrometry. Integrating PRISM with front-end IgY14 immunoaffinity depletion, sensitive detection of targeted proteins at 50-100 pg/mL levels in human blood plasma/serum was demonstrated. However, immunoaffinity depletion is often associated with undesired losses of target proteins of interest. Herein we report further evaluation of PRISM-SRM quantification of low-abundance serum proteins without immunoaffinity depletion and the multiplexing potential of this technique. Limits of quantification (LOQs) at low ng/mL levels with a medianmore » CV of ~12% were achieved for proteins spiked into human female serum using as little as 2 µL serum. PRISM-SRM provided up to ~1000-fold improvement in the LOQ when compared to conventional SRM measurements. Multiplexing capability of PRISM-SRM was also evaluated by two sets of serum samples with 6 and 21 target peptides spiked at the low attomole/µL levels. The results from SRM measurements for pooled or post-concatenated samples were comparable to those obtained from individual peptide fractions in terms of signal-to-noise ratios and SRM peak area ratios of light to heavy peptides. PRISM-SRM was applied to measure several ng/mL-level endogenous plasma proteins, including prostate-specific antigen, in clinical patient sera where correlation coefficients > 0.99 were observed between the results from PRISM-SRM and ELISA assays. Our results demonstrate that PRISM-SRM can be successfully used for quantification of low-abundance endogenous proteins in highly complex samples. Moderate throughput (50 samples/week) can be achieved by applying the post-concatenation or fraction multiplexing strategies. We anticipate broad applications for targeted PRISM-SRM quantification of low-abundance cellular proteins in systems biology studies as well as candidate biomarkers in biofluids.« less

Trade-offs of Solar Geoengineering and Mitigation under Climate Targets

NASA Astrophysics Data System (ADS)

Mohammadi Khabbazan, M.; Stankoweit, M.; Roshan, E.; Schmidt, H.; Held, H.

2016-12-01

Scientific analyses have hitherto focused on the pros and cons of solar-radiation management (SRM) as a climate-policy option mainly in mere isolation. Here we put SRM into the context of mitigation by a strictly temperature-target-based approach. To the best of our knowledge, for the first time, we introduce a concept for a regional integrated analysis of SRM and mitigation in-line with the `2°C target'. We explicitly account for a risk-risk comparison of SRM and global warming, extending the applicability regime of temperature targets from mitigation-only to joint-SRM-mitigation analysis while minimizing economic costs required for complying with the 2°C target. Upgrading it to include SRM, we employ the integrated energy-economy-climate model MIND. We utilize the two-box climate model of DICE and calibrate the short and long time scales respectively into GeoMIP G3 experiment and quadrupled atmospheric CO2 concentrations experiment from CEMIP5 suite. Our results show that without risk-risk accounting SRM will displace mitigation. However, our analysis highlights that the value system enshrined in the 2°C target can almost preclude SRM; this is exemplified by one single regional climate variable, here precipitation, which is confined to regional bounds compatible with 2°C of global warming. Although about a half of policy costs can be saved, the results indicate that the additional amount of CO2 that could be released to the atmosphere corresponds to only 0.2°C of further global warming. Hence, the society might debate whether the risks of SRM should be taken for that rather small amount of additional carbon emissions. Nonetheless, our results point out a significantly larger role for SRM implementation if the guardrails of some regions are relaxed.

Response of selected plant and insect species to simulated SRM exhaust mixtures and to exhaust components from SRM fuels

NASA Technical Reports Server (NTRS)

Heck, W. W.

1980-01-01

The possible biologic effects of exhaust products from solid rocket motor (SRM) burns associated with the space shuttle are examined. The major components of the exhaust that might have an adverse effect on vegetation, HCl and Al2O3 are studied. Dose response curves for native and cultivated plants and selected insects exposed to simulated exhaust and component chemicals from SRM exhaust are presented. A system for dispensing and monitoring component chemicals of SRM exhaust (HCl and Al2O3) and a system for exposing test plants to simulated SRM exhaust (controlled fuel burns) are described. The effects of HCl, Al2O3, and mixtures of the two on the honeybee, the corn earworm, and the common lacewing and the effects of simulated exhaust on the honeybee are discussed.

Estimating the Global Agricultural Impact of Solar Radiation Management using Volcanic Eruptions as Natural Experiments

NASA Astrophysics Data System (ADS)

Proctor, J.; Hsiang, S. M.; Burney, J. A.; Burke, M.; Schlenker, W.

2017-12-01

Solar radiation management (SRM) is increasingly considered an option for managing global temperatures, yet the economic impacts of ameliorating climatic changes by scattering sunlight back to space remain largely unknown. Though SRM may increase crop yields by reducing heat stress, its impacts from concomitant changes in available sunlight have never been empirically estimated. Here we use the volcanic eruptions that inspired modern SRM proposals as natural experiments to provide the first estimates of how the stratospheric sulfate aerosols (SS) created by the eruptions of El Chichon and Pinatubo altered the quantity and quality of global sunlight, how those changes in sunlight impacted global crop yields, and the total effect that SS may have on yields in an SRM scenario when the climatic and sunlight effects are jointly considered. We find that the sunlight-mediated impact of SS on yields is negative for both C4 (maize) and C3 (soy, rice, wheat) crops. Applying our yield model to a geoengineering scenario using SS-based SRM from 2050-2069, we find that SRM damages due to scattering sunlight are roughly equal in magnitude to SRM benefits from cooling. This suggests that SRM - if deployed using SS similar to those emitted by the volcanic eruptions it seeks to mimic - would attenuate little of the damages from climate change to global agriculture on net. Our approach could be extended to study SRM impacts on other global systems, such as human health or ecosystem function.

Selected reaction monitoring (SRM) mass spectrometry without isotope labeling can be used for rapid protein quantification

PubMed Central

Zhi, Wenbo; Wang, Meiyao

2014-01-01

The validation of putative biomarker candidates has become the major bottle-neck in protein biomarker development. Conventional immunoaffinity methods are limited by the availability of antibodies and kits. Here we demonstrated the feasibility of using the selected reaction monitoring (SRM) without isotope labeling to achieve fast and reproducible quantification of serum proteins. The SRM/MRM assays for three standard serum proteins, including ceruloplasmin (CP), serum aymloid A (SAA) and sex hormone binding globulin (SHBG) have good linear ranges, generally 103 – 104. There are almost perfect correlations between SRM intensities and the loaded peptide amounts (R2 is usually ~0.99). Our data suggest that SRM/MRM is able to quantify proteins at 0.2 – 2 fmol level, which are comparable to the commercial ELISA/LUMINEX kits for these proteins. Excellent correlations between SRM/MRM and ELISA/LUMINEX assays were observed for SAA and SHBG (R2 = 0.928 and 0.851 respectively). The correlation between SRM/MRM and ELISA for CP is less desirable (R2 = 0.565). The reproducibility for SRM/MRM assays is generally very good but may depend on the proteins/peptides (R2 = 0.931 and 0.882 for SAA and SHBG, and 0.723 for CP). SRM/MRM assay without isotope labeling is a rapid and useful method for protein biomarker validation in a modest number of samples and is especially useful when other assays such as ELISA or Luminex beads are not available. PMID:21594933

Targeted quantification of low ng/mL level proteins in human serum without immunoaffinity depletion

PubMed Central

Shi, Tujin; Sun, Xuefei; Gao, Yuqian; Fillmore, Thomas L.; Schepmoes, Athena A.; Zhao, Rui; He, Jintang; Moore, Ronald J.; Kagan, Jacob; Rodland, Karin D.; Liu, Tao; Liu, Alvin Y.; Smith, Richard D.; Tang, Keqi; Camp, David G.; Qian, Wei-Jun

2013-01-01

We recently reported an antibody-free targeted protein quantification strategy, termed high-pressure, high-resolution separations with intelligent selection and multiplexing (PRISM) for achieving significantly enhanced sensitivity using selected reaction monitoring (SRM) mass spectrometry. Integrating PRISM with front-end IgY14 immunoaffinity depletion, sensitive detection of targeted proteins at 50–100 pg/mL levels in human blood plasma/serum was demonstrated. However, immunoaffinity depletion is often associated with undesired losses of target proteins of interest. Herein we report further evaluation of PRISM-SRM quantification of low-abundance serum proteins without immunoaffinity depletion. Limits of quantification (LOQ) at low ng/mL levels with a median coefficient of variation (CV) of ~12% were achieved for proteins spiked into human female serum. PRISM-SRM provided >100-fold improvement in the LOQ when compared to conventional LC-SRM measurements. PRISM-SRM was then applied to measure several low-abundance endogenous serum proteins, including prostate-specific antigen (PSA), in clinical prostate cancer patient sera. PRISM-SRM enabled confident detection of all target endogenous serum proteins except the low pg/mL-level cardiac troponin T. A correlation coefficient >0.99 was observed for PSA between the results from PRISM-SRM and immunoassays. Our results demonstrate that PRISM-SRM can successful quantify low ng/mL proteins in human plasma or serum without depletion. We anticipate broad applications for PRISM-SRM quantification of low-abundance proteins in candidate biomarker verification and systems biology studies. PMID:23763644

Advanced Multi-phase Flow CFD Model Development for Solid Rocket Motor Flowfield Analysis

NASA Technical Reports Server (NTRS)

Liaw, Paul; Chen, Yen-Sen

1995-01-01

A Navier-Stokes code, finite difference Navier-Stokes (FDNS), is used to analyze the complicated internal flowfield of the SRM (solid rocket motor) to explore the impacts due to the effects of chemical reaction, particle dynamics, and slag accumulation on the solid rocket motor (SRM). The particulate multi-phase flowfield with chemical reaction, particle evaporation, combustion, breakup, and agglomeration models are included in present study to obtain a better understanding of the SRM design. Finite rate chemistry model is applied to simulate the chemical reaction effects. Hermsen correlation model is used for the combustion simulation. The evaporation model introduced by Spalding is utilized to include the heat transfer from the particulate phase to the gase phase due to the evaporation of the particles. A correlation of the minimum particle size for breakup expressed in terms of the Al/Al2O3 surface tension and shear force was employed to simulate the breakup of particles. It is assumed that the breakup occurs when the Weber number exceeds 6. A simple L agglomeration model is used to investigate the particle agglomeration. However, due to the large computer memory requirements for the agglomeration model, only 2D cases are tested with the agglomeration model. The VOF (Volume of Fluid) method is employed to simulate the slag buildup in the aft-end cavity of the redesigned solid rocket motor (RSRM). Monte Carlo method is employed to calculate the turbulent dispersion effect of the particles. The flowfield analysis obtained using the FDNS code in the present research with finite rate chemical reaction, particle evaporation, combustion, breakup, agglomeration, and VOG models will provide a design guide for the potential improvement of the SRM including the use of materials and the shape of nozzle geometry such that a better performance of the SRM can be achieved. The simulation of the slag buildup in the aft-end cavity can assist the designer to improve the design of the RSRM geometry.

Deep-Dive Targeted Quantification for Ultrasensitive Analysis of Proteins in Nondepleted Human Blood Plasma/Serum and Tissues

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

Nie, Song; Shi, Tujin; Fillmore, Thomas L.

Mass spectrometry-based targeted proteomics (e.g., selected reaction monitoring, SRM) is emerging as an attractive alternative to immunoassays for protein quantification. Recently we have made significant progress in SRM sensitivity for enabling quantification of low ng/mL to sub-ng/mL level proteins in nondepleted human blood plasma/serum without affinity enrichment. However, precise quantification of extremely low abundant but biologically important proteins (e.g., ≤100 pg/mL in blood plasma/serum) using targeted proteomics approaches still remains challenging. To address this need, we have developed an antibody-independent Deep-Dive SRM (DD-SRM) approach that capitalizes on multidimensional high-resolution reversed-phase liquid chromatography (LC) separation for target peptide enrichment combined withmore » precise selection of target peptide fractions of interest, significantly improving SRM sensitivity by ~5 orders of magnitude when compared to conventional LC-SRM. Application of DD-SRM to human serum and tissue has been demonstrated to enable precise quantification of endogenous proteins at ~10 pg/mL level in nondepleted serum and at <10 copies per cell level in tissue. Thus, DD-SRM holds great promise for precisely measuring extremely low abundance proteins or protein modifications, especially when high-quality antibody is not available.« less

Evaluating MODIS snow products for modelling snowmelt runoff: Case study of the Rio Grande headwaters

NASA Astrophysics Data System (ADS)

Steele, Caitriana; Dialesandro, John; James, Darren; Elias, Emile; Rango, Albert; Bleiweiss, Max

2017-12-01

Snow-covered area (SCA) is a key variable in the Snowmelt-Runoff Model (SRM) and in other models for simulating discharge from snowmelt. Landsat Thematic Mapper (TM), Enhanced Thematic Mapper (ETM +) or Operational Land Imager (OLI) provide remotely sensed data at an appropriate spatial resolution for mapping SCA in small headwater basins, but the temporal resolution of the data is low and may not always provide sufficient cloud-free dates. The coarser spatial resolution Moderate Resolution Imaging Spectroradiometer (MODIS) offers better temporal resolution and in cloudy years, MODIS data offer the best alternative for mapping snow cover when finer spatial resolution data are unavailable. However, MODIS' coarse spatial resolution (500 m) can obscure fine spatial patterning in snow cover and some MODIS products are not sensitive to end-of-season snow cover. In this study, we aimed to test MODIS snow products for use in simulating snowmelt runoff from smaller headwater basins by a) comparing maps of TM and MODIS-based SCA and b) determining how SRM streamflow simulations are changed by the different estimates of seasonal snow depletion. We compared gridded MODIS snow products (Collection 5 MOD10A1 fractional and binary SCA; SCA derived from Collection 6 MOD10A1 Normalised Difference Snow Index (NDSI) Snow Cover), and the MODIS Snow Covered-Area and Grain size retrieval (MODSCAG) canopy-corrected fractional SCA (SCAMG), with reference SCA maps (SCAREF) generated from binary classification of TM imagery. SCAMG showed strong agreement with SCAREF; excluding true negatives (where both methods agreed no snow was present) the median percent difference between SCAREF and SCAMG ranged between -2.4% and 4.7%. We simulated runoff for each of the four study years using SRM populated with and calibrated for snow depletion curves derived from SCAREF. We then substituted in each of the MODIS-derived depletion curves. With efficiency coefficients ranging between 0.73 and 0.93, SRM simulation results from the SCAMG runs yielded the best results of all the MODIS products and only slightly underestimated discharge volume (between 7 and 11% of measured annual discharge). SRM simulations that used SCA derived from Collection 6 NDSI Snow Cover also yielded promising results, with efficiency coefficients ranging between 0.73 and 0.91. In conclusion, we recommend that when simulating snowmelt runoff from small basins (<4000 km2) with SRM, we recommend that users select either canopy-corrected MODSCAG or create their own site-specific products from the Collection 6 MOD10A1 NDSI.

Use of sol-gels as solid matrixes for simultaneous multielement determination by radio frequency glow discharge optical emission spectrometry: determinations of suspended particulate matter.

PubMed

Davis, W Clay; Knippel, Brad C; Cooper, Julia E; Spraul, Bryan K; Rice, Jeanette K; Smith, Dennis W; Marcus, R Kenneth

2003-05-15

A new approach for the analysis of particulate matter by radio frequency glow discharge optical emission spectrometry (rf-GD-OES) is described. Dispersion of the particles in a sol-gel sample matrix provides a convenient means of generating a thin film suitable for sputter-sampling into the discharge. Acid-catalyzed sol-gel glasses synthesized from tetramethyl orthosilicate were prepared and spun-cast on glass substrates. The resultant thin films on glass substrates were analyzed to determine the discharge operating conditions and resultant sputtering characteristics while a number of optical emission lines of the film components were monitored. Slurries of powdered standard reference materials NIST SRM 1884a (Portland Cement) and NIST SRM 2690 (Coal Fly Ash) dispersed in the sols were cast into films in the same manner. Use of the sol-gels as sample matrixes allows for background subtraction through the use of analytical blanks and may facilitate the generation of calibration curves via readily synthesized, matrix-matched analytical standards in solids analysis. Detection limits were determined for minor elements via the RSDB method to be in the range of 1-10 microg/g in Portland Cement and Coal Fly Ash samples for the elements Al, Fe, Mg, S, and Si. Values for Ca were in the range of 15-35 microg/g. This preliminary study demonstrates the possibility of incorporating various insoluble species, including ceramics and geological specimens in powder form, into a solid matrix for further analysis by either rf-GD-OES or MS.

Non-PBDE halogenated flame retardants in Canadian indoor house dust: sampling, analysis, and occurrence.

PubMed

Fan, Xinghua; Kubwabo, Cariton; Rasmussen, Pat E; Wu, Fang

2016-04-01

An analytical method was developed for the measurement of 18 novel halogenated flame retardants in house dust. Sample preparation was based on ultrasound-assisted solvent extraction and clean up with solid phase extraction (SPE). Sample extracts were analyzed by gas chromatography-mass spectrometry (GC/MS) operated in electron capture negative ion (ECNI) chemical ionization mode. Baseline data from 351 fresh (active) dust samples collected under the Canadian House Dust Study (CHDS) revealed that five out of 18 target chemicals were present with detection frequencies higher than 90 %. Median (range) concentrations for these five compounds were as follows: 104 (<1.5-13,000) ng/g for 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTBB), 8.5 (<1.7-2390) ng/g for 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), 10.2 (<1.7-430) ng/g for hexabromobenzene (HBB), 2.9 (<1.2-1410) ng/g for syn-dechlorane plus (syn-DP) and 5.6 (<1.9-1570) ng/g for anti-dechlorane plus (anti-DP). A comparison of two sampling methods in a subset of 40 homes showed significant positive correlations between samples of "active" dust and samples taken directly from the household vacuum cleaner for all target compounds having median values above their corresponding method detection limits (MDLs). In addition, the method was also applied to the analysis of the targeted compounds in National Institute of Standards and Technology (NIST) standard reference material (SRM 2585, organic contaminants in house dust). Results from the current study could contribute to the potential certification of target chemicals in SRM 2585.

Comparison of gas chromatography-combustion-mass spectrometry and gas chromatography-flame ionization detector for the determination of fatty acid methyl esters in biodiesel without specific standards.

PubMed

Sobrado, Laura Alonso; Freije-Carrelo, Laura; Moldovan, Mariella; Encinar, Jorge Ruiz; Alonso, J Ignacio García

2016-07-29

GC-FID has been effectively used as a universal quantification technique for volatile organic compounds for a long time. In most cases, the use of the ECN allows for quantification by GC-FID without external calibration using only the response of a single internal standard. In this paper we compare the performance characteristics of GC-FID with those of post-column (13)C Isotope Dilution GC-Combustion-MS for the absolute quantification of organic compounds without the need for individual standards. For this comparison we have selected the quantification of FAMEs in biodiesel. The selection of the right internal standard was critical for GC-FID even when ECN were considered. On the other hand, the nature of the internal standard was not relevant when GC-Combustion-MS was employed. The proposed method was validated with the analysis of the certified reference material SRM 2772 and comparative data was obtained on real biodiesel samples. The analysis of the SRM 2772 biodiesel provided recoveries in the range 100.6-103.5% and 96.4-103.6% for GC-combustion-MS and GC-FID, respectively. The detection limit for GC-combustion-MS was found to be 4.2ng compound/g of injected sample. In conclusion, the quantitative performance of GC-Combustion-MS compared satisfactorily with that of GC-FID constituting a viable alternative for the quantification of organic compounds without the need for individual standards. Copyright © 2016 Elsevier B.V. All rights reserved.

Single-laboratory validation of a high-performance liquid chromatographic-diode array detector-fluorescence detector/mass spectrometric method for simultaneous determination of water-soluble vitamins in multivitamin dietary tablets.

PubMed

Chen, Pei; Atkinson, Renata; Wolf, Wayne R

2009-01-01

The purpose of this study was to develop a single-laboratory validated (SLV) method using high-performance liquid chromatography with different detectors [diode array detector (DAD); fluorescence detector (FLD); and mass spectrometry (MS)] for determination of 7 B-complex vitamins (B1-thiamin, B2-riboflavin, B3-nicotinamide, B6-pyridoxine, B9-folic acid, pantothenic acid, and biotin) and vitamin C in multivitamin/multimineral dietary supplements. The method involves the use of a reversed-phase octadecylsilyl column (4 microm, 250 x 2.0 mm id) and a gradient mobile phase profile. Gradient elution was performed at a flow rate of 0.25 mL/min. After a 5 min isocratic elution at 100% A (0.1% formic acid in water), a linear gradient to 50% A and 50% B (0.1% formic acid in acetonitrile) at 15 min was employed. Detection was performed with a DAD as well as either an FLD or a triple-quadrupole MS detector in the multiple reaction monitoring mode. SLV was performed using Standard Reference Material (SRM) 3280 Multivitamin/Multimineral Tablets, being developed by the National Institute of Standards and Technology, with support by the Office of Dietary Supplements of the National Institutes of Health. Phosphate buffer (10 mM, pH 2.0) extracts of the NIST SRM 3280 were analyzed by the liquid chromatographic (LC)-DAD-FLDIMS method. Following extraction, the method does not require any sample cleanup/preconcentration steps except centrifugation and filtration.

Single-Laboratory Validation of a High-Performance Liquid Chromatographic-Diode Array Detector-Fluorescence Detector/Mass Spectrometric Method for Simultaneous Determination of Water-Soluble Vitamins in Multivitamin Dietary Tablets

PubMed Central

Chen, Pei; Atkinson, Renata; Wolf, Wayne R.

2014-01-01

The purpose of this study was to develop a single-laboratory validated (SLV) method using high-performance liquid chromatography with different detectors [diode array detector (DAD); fluorescence detector (FLD); and mass spectrometry (MS)] for determination of 7 B-complex vitamins (B1-thiamin, B2-riboflavin, B3-nicotinamide, B6-pyridoxine, B9-folic acid, pantothenic acid, and biotin) and vitamin C in multivitamin/multimineral dietary supplements. The method involves the use of a reversed-phase octadecylsilyl column (4 µm, 250 × 2.0 mm id) and a gradient mobile phase profile. Gradient elution was performed at a flow rate of 0.25 mL/min. After a 5 min isocratic elution at 100% A (0.1% formic acid in water), a linear gradient to 50% A and 50% B (0.1% formic acid in acetonitrile) at 15 min was employed. Detection was performed with a DAD as well as either an FLD or a triple-quadrupole MS detector in the multiple reaction monitoring mode. SLV was performed using Standard Reference Material (SRM) 3280 Multivitamin/Multimineral Tablets, being developed by the National Institute of Standards and Technology, with support by the Office of Dietary Supplements of the National Institutes of Health. Phosphate buffer (10 mM, pH 2.0) extracts of the NIST SRM 3280 were analyzed by the liquid chromatographic (LC)-DAD-FLD/MS method. Following extraction, the method does not require any sample cleanup/preconcentration steps except centrifugation and filtration. PMID:19485230

Halloysite nanotubes as a solid sorbent in ultrasound-assisted dispersive micro solid-phase extraction for the determination of bismuth in water samples using high-resolution continuum source graphite-furnace atomic absorption spectrometry

NASA Astrophysics Data System (ADS)

Krawczyk-Coda, Magdalena

2017-03-01

In this research, a simple, accurate, and inexpensive preconcentration procedure was developed for the determination of bismuth in water samples, using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS). During the preconcentration step, halloysite nanotubes (HNTs) were used as a solid sorbent in ultrasound-assisted dispersive micro solid-phase extraction (USA DMSPE). The influence of the pH of the sample solution, amount of HNTs, and extraction time, as well as of the main parameters of HR CS GFAAS, on absorbance was investigated. The limit of detection was 0.005 μg L- 1. The preconcentration factor achieved for bismuth was 32. The relative standard deviation (RSD) was 4%. The accuracy of this method was validated by analyses of NIST SRM 1643e (Trace elements in water) and TMDA-54.5 (A high level fortified sample for trace elements) certified reference materials. The measured bismuth contents in these certified reference materials were in satisfactory agreement with the certified values according to the t-test for a 95% confidence level. The proposed method has been successfully applied to the determination of bismuth in five different real water samples (seawater, lake water, river water, stream water and rain water).

Development of an on-line flow injection Sr/matrix separation method for accurate, high-throughput determination of Sr isotope ratios by multiple collector-inductively coupled plasma-mass spectrometry.

PubMed

Galler, Patrick; Limbeck, Andreas; Boulyga, Sergei F; Stingeder, Gerhard; Hirata, Takafumi; Prohaska, Thomas

2007-07-01

This work introduces a newly developed on-line flow injection (FI) Sr/Rb separation method as an alternative to the common, manual Sr/matrix batch separation procedure, since total analysis time is often limited by sample preparation despite the fast rate of data acquisition possible by inductively coupled plasma-mass spectrometers (ICPMS). Separation columns containing approximately 100 muL of Sr-specific resin were used for on-line FI Sr/matrix separation with subsequent determination of (87)Sr/(86)Sr isotope ratios by multiple collector ICPMS. The occurrence of memory effects exhibited by the Sr-specific resin, a major restriction to the repetitive use of this costly material, could successfully be overcome. The method was fully validated by means of certified reference materials. A set of two biological and six geological Sr- and Rb-bearing samples was successfully characterized for its (87)Sr/(86)Sr isotope ratios with precisions of 0.01-0.04% 2 RSD (n = 5-10). Based on our measurements we suggest (87)Sr/(86)Sr isotope ratios of 0.713 15 +/- 0.000 16 (2 SD) and 0.709 31 +/- 0.000 06 (2 SD) for the NIST SRM 1400 bone ash and the NIST SRM 1486 bone meal, respectively. Measured (87)Sr/(86)Sr isotope ratios for five basalt samples are in excellent agreement with published data with deviations from the published value ranging from 0 to 0.03%. A mica sample with a Rb/Sr ratio of approximately 1 was successfully characterized for its (87)Sr/(86)Sr isotope signature to be 0.718 24 +/- 0.000 29 (2 SD) by the proposed method. Synthetic samples with Rb/Sr ratios of up to 10/1 could successfully be measured without significant interferences on mass 87, which would otherwise bias the accuracy and uncertainty of the obtained data.

Study of solid rocket motors for a space shuttle booster, volume 2

NASA Technical Reports Server (NTRS)

1972-01-01

Additional technical data have been prepared to supplement the data supplied in the SRM shuttle booster final report. These data cover performance characteristics utilizing motor efficiencies of 0.960 and 0.947 with nozzle divergence half angles of 15 deg and 20 deg, respectively; PBAN propellant characteristics; parametric data to extend baseline designs to varying states of SRM's; summary of SRM mass properties; and SRM exhaust plume profiles.

How does the sensitivity of climate affect stratospheric solar radiation management?

NASA Astrophysics Data System (ADS)

Ricke, K.; Rowlands, D. J.; Ingram, W.; Keith, D.; Morgan, M. G.

2011-12-01

If implementation of proposals to engineer the climate through solar radiation management (SRM) ever occurs, it is likely to be contingent upon climate sensitivity. Despite this, no modeling studies have examined how the effectiveness of SRM forcings differs between the typical Atmosphere-Ocean General Circulation Models (AOGCMs) with climate sensitivities close to the Coupled Model Intercomparison Project (CMIP) mean and ones with high climate sensitivities. Here, we use a perturbed physics ensemble modeling experiment to examine variations in the response of climate to SRM under different climate sensitivities. When SRM is used as a substitute for mitigation its ability to maintain the current climate state gets worse with increased climate sensitivity and with increased concentrations of greenhouse gases. However, our results also demonstrate that the potential of SRM to slow climate change, even at the regional level, grows with climate sensitivity. On average, SRM reduces regional rates of temperature change by more than 90 percent and rates of precipitation change by more than 50 percent in these higher sensitivity model configurations. To investigate how SRM might behave in models with high climate sensitivity that are also consistent with recent observed climate change we perform a "perturbed physics" ensemble (PPE) modelling experiment with the climateprediction.net (cpdn) version of the HadCM3L AOGCM. Like other perturbed physics climate modelling experiments, we simulate past and future climate scenarios using a wide range of model parameter combinations that both reproduce past climate within a specified level of accuracy and simulate future climates with a wide range of climate sensitivities. We chose 43 members ("model versions") from a subset of the 1,550 from the British Broadcasting Corporation (BBC) climateprediction.net project that have data that allow restarts. We use our results to explore how much assessments of SRM that use best-estimate models, and so near-median climate sensitivity, may be ignoring important contingencies associated with implementing SRM in reality. A primary motivation for studying SRM via the injection of aerosols in the stratosphere is to evaluate its potential effectiveness as "insurance" in the case of higher-than-expected climate response to global warming. We find that this is precisely when SRM appears to be least effective in returning regional climates to their baseline states and reducing regional rates of precipitation change. On the other hand, given the very high regional temperature anomalies associated with rising greenhouse gas concentrations in high sensitivity models, it is also where SRM is most effective in reducing rates of change relative to a no SRM alternative.

Effects of geoengineering on crop yields

NASA Astrophysics Data System (ADS)

Pongratz, J.; Lobell, D. B.; Cao, L.; Caldeira, K.

2011-12-01

The potential of "solar radiation management" (SRM) to reduce future climate change and associated risks has been receiving significant attention in scientific and policy circles. SRM schemes aim to reduce global warming despite increasing atmospheric CO2 concentrations by diminishing the amount of solar insolation absorbed by the Earth, for example, by injecting scattering aerosols into the atmosphere. Climate models predict that SRM could fully compensate warming at the global mean in a high-CO2 world. While reduction of global warming may offset a part of the predicted negative effects of future climate change on crop yields, SRM schemes are expected to alter regional climate and to have substantial effects on climate variables other than temperature, such as precipitation. It has therefore been warned that, overall, SRM may pose a risk to food security. Assessments of benefits and risks of geoengineering are imperative, yet such assessments are only beginning to emerge; in particular, effects on global food security have not previously been assessed. Here, for the first time, we combine climate model simulations with models of crop yield responses to climate to assess large-scale changes in yields and food production under SRM. In most crop-growing regions, we find that yield losses caused by climate changes are substantially reduced under SRM as compared with a non-geoengineered doubling of atmospheric CO2. Substantial yield losses with SRM are only found for rice in high latitudes, where the limits of low temperatures are no longer alleviated. At the same time, the beneficial effect of CO2-fertilization on plant productivity remains active. Overall therefore, SRM in our models causes global crop yields to increase. We estimate the direct effects of climate and CO2 changes on crop production, and do not quantify effects of market dynamics and management changes. We note, however, that an SRM deployment would be unlikely to maintain the economic status quo, as market shares of agricultural output may change with the different spatial pattern of climate change. More importantly, geoengineering by SRM does not address a range of other detrimental consequences of climate change, such as ocean acidification, which could also affect food security via effects on marine food webs. Finally, SRM poses substantial anticipated and unanticipated risks by interfering with complex, not fully understood systems. Therefore, despite potential positive effects of SRM on crop yields, the most certain way to reduce climate risks to global food security is to reduce emissions of greenhouse gases.

DNA barcoding detects contamination and substitution in North American herbal products

PubMed Central

2013-01-01

Background Herbal products available to consumers in the marketplace may be contaminated or substituted with alternative plant species and fillers that are not listed on the labels. According to the World Health Organization, the adulteration of herbal products is a threat to consumer safety. Our research aimed to investigate herbal product integrity and authenticity with the goal of protecting consumers from health risks associated with product substitution and contamination. Methods We used DNA barcoding to conduct a blind test of the authenticity for (i) 44 herbal products representing 12 companies and 30 different species of herbs, and (ii) 50 leaf samples collected from 42 herbal species. Our laboratory also assembled the first standard reference material (SRM) herbal barcode library from 100 herbal species of known provenance that were used to identify the unknown herbal products and leaf samples. Results We recovered DNA barcodes from most herbal products (91%) and all leaf samples (100%), with 95% species resolution using a tiered approach (rbcL + ITS2). Most (59%) of the products tested contained DNA barcodes from plant species not listed on the labels. Although we were able to authenticate almost half (48%) of the products, one-third of these also contained contaminants and or fillers not listed on the label. Product substitution occurred in 30/44 of the products tested and only 2/12 companies had products without any substitution, contamination or fillers. Some of the contaminants we found pose serious health risks to consumers. Conclusions Most of the herbal products tested were of poor quality, including considerable product substitution, contamination and use of fillers. These activities dilute the effectiveness of otherwise useful remedies, lowering the perceived value of all related products because of a lack of consumer confidence in them. We suggest that the herbal industry should embrace DNA barcoding for authenticating herbal products through testing of raw materials used in manufacturing products. The use of an SRM DNA herbal barcode library for testing bulk materials could provide a method for 'best practices? in the manufacturing of herbal products. This would provide consumers with safe, high quality herbal products. PMID:24120035

Broadband Photometric Reverberation Mapping Analysis on SDSS-RM and Stripe 82 Quasars

NASA Astrophysics Data System (ADS)

Zhang, Haowen; Yang, Qian; Wu, Xue-Bing

2018-02-01

We modified the broadband photometric reverberation mapping (PRM) code, JAVELIN, and tested the availability to get broad-line region time delays that are consistent with the spectroscopic reverberation mapping (SRM) project SDSS-RM. The broadband light curves of SDSS-RM quasars produced by convolution with the system transmission curves were used in the test. We found that under similar sampling conditions (evenly and frequently sampled), the key factor determining whether the broadband PRM code can yield lags consistent with the SRM project is the flux ratio of the broad emission line to the reference continuum, which is in line with the previous findings. We further found a critical line-to-continuum flux ratio, about 6%, above which the mean of the ratios between the lags from PRM and SRM becomes closer to unity, and the scatter is pronouncedly reduced. We also tested our code on a subset of SDSS Stripe 82 quasars, and found that our program tends to give biased lag estimations due to the observation gaps when the R-L relation prior in Markov Chain Monte Carlo is discarded. The performance of the damped random walk (DRW) model and the power-law (PL) structure function model on broadband PRM were compared. We found that given both SDSS-RM-like or Stripe 82-like light curves, the DRW model performs better in carrying out broadband PRM than the PL model.

Optimizing signal recycling for detecting a stochastic gravitational-wave background

NASA Astrophysics Data System (ADS)

Tao, Duo; Christensen, Nelson

2018-06-01

Signal recycling is applied in laser interferometers such as the Advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO) to increase their sensitivity to gravitational waves. In this study, signal recycling configurations for detecting a stochastic gravitational wave background are optimized based on aLIGO parameters. Optimal transmission of the signal recycling mirror (SRM) and detuning phase of the signal recycling cavity under a fixed laser power and low-frequency cutoff are calculated. Based on the optimal configurations, the compatibility with a binary neutron star (BNS) search is discussed. Then, different laser powers and low-frequency cutoffs are considered. Two models for the dimensionless energy density of gravitational waves , the flat model and the model, are studied. For a stochastic background search, it is found that an interferometer using signal recycling has a better sensitivity than an interferometer not using it. The optimal stochastic search configurations are typically found when both the SRM transmission and the signal recycling detuning phase are low. In this region, the BNS range mostly lies between 160 and 180 Mpc. When a lower laser power is used the optimal signal recycling detuning phase increases, the optimal SRM transmission increases and the optimal sensitivity improves. A reduced low-frequency cutoff gives a better sensitivity limit. For both models of , a typical optimal sensitivity limit on the order of 10‑10 is achieved at a reference frequency of Hz.

Solid-propellant rocket motor internal ballistics performance variation analysis, phase 5

NASA Technical Reports Server (NTRS)

Sforzini, R. H.; Murph, J. E.

1980-01-01

The results of research aimed at improving the predictability of internal ballistics performance of solid-propellant rocket motors (SRM's) including thrust imbalance between two SRM's firing in parallel are presented. Static test data from the first six Space Shuttle SRM's is analyzed using a computer program previously developed for this purpose. The program permits intentional minor design biases affecting the imbalance between any two SMR's to be removed. Results for the last four of the six SRM's, with only the propellant bulk temperature as a non-random variable, are generally within limits predicted by theory. Extended studies of internal ballistic performance of single SRM's are presented based on an earlier developed mathematical model which includes an assessment of grain deformation. The erosive burning rate law used in the model is upgraded and made more general. Excellent results are obtained in predictions of the performances of five different SRM's of quite different sizes and configurations. These SRM's all employ PBAN type propellants with ammonium perchlorate oxidizer and 16 to 20% aluminum except one which uses carboxyl terminated butadiene binder. The only non-calculated parameters in the burning rate equations that are changed for the different SRM's are the zero crossflow velocity burning rate coefficients and exponents. The results, in general, confirm the importance of grain deformation. The improved internal ballistic model makes practical development of an effective computer program for application of an optimization technique to SRM design which is also demonstrated. The program uses a pattern search technique to minimize the difference between a desired thrust-time trace and one calculated based on the internal ballistic model.

An Internal Thermal Environment Model of an Aluminized Solid Rocket Motor with Experimental Validation

NASA Technical Reports Server (NTRS)

Martin, Heath T.

2015-01-01

Due to the severity of the internal solid rocket motor (SRM) environment, very few direct measurements of that environment exist; therefore, the appearance of such data provides a unique opportunity to assess current thermal/fluid modeling capabilities. As part of a previous study of SRM internal insulation performance, the internal thermal environment of a laboratory-scale SRM featuring aluminized propellant was characterized with two types of custom heat-flux calorimeters: one that measured the total heat flux to a graphite slab within the SRM chamber and another that measured the thermal radiation flux. Therefore, in the current study, a thermal/fluid model of this lab-scale SRM was constructed using ANSYS Fluent to predict not only the flow field structure within the SRM and the convective heat transfer to the interior walls, but also the resulting dispersion of alumina droplets and the radiative heat transfer to the interior walls. The dispersion of alumina droplets within the SRM chamber was determined by employing the Lagrangian discrete phase model that was fully coupled to the Eulerian gas-phase flow. The P1-approximation was engaged to model the radiative heat transfer through the SRM chamber where the radiative contributions of the gas phase were ignored and the aggregate radiative properties of the alumina dispersion were computed from the radiative properties of its individual constituent droplets, which were sourced from literature. The convective and radiative heat fluxes computed from the thermal/fluid model were then compared with those measured in the lab-scale SRM test firings and the modeling approach evaluated.

Solar radiation management - on feasibility, side effects, and reaching the 2 degree target

NASA Astrophysics Data System (ADS)

Korhonen, Hannele; Laakso, Anton; Ekholm, Tommi; Maalick, Zubair; Partanen, Antti-Ilari; Kokkola, Harri; Romakkaniemi, Sami

2015-04-01

Solar radiation management (SRM), i.e. artificially increasing the reflectivity of the Earth, has been suggested as a fast-response, low-cost method to mitigate the impacts of potential rapid future climate change. We have used 1) large eddy simulations as well as an aerosol-climate model and an earth system model to investigate the feasibility and side effects of two types of SRM (marine cloud brightening and stratospheric sulfur injections) and 2) a sequential decision-making approach to determine strategies that combine emission reductions and an uncertain SRM option to limit global mean temperature increase to 2 degree. Regarding stratospheric injections, we find that a large explosive volcanic eruption taking place while SRM is in full force would result in overcooling of the planet, as expected; however, the radiative and climate effects would be clearly smaller than could be expected from the sum of the effects from volcanic eruption alone or SRM alone. In addition, the stratospheric sulphur load would recover from the eruption faster under SRM and natural conditions. If the eruption took place in the high latitudes, the resulting global forcing would be highly dependent on the season of the eruption. Furthermore, regarding marine cloud brightening we find that the spraying of sea water drops leads to cooling due to evaporation and leads to delay in particle dispersion. This delay enhances particle scavenging, and can influence the efficacy of cloud seeding. In terms of combining emission reductions and SRM to reach the 2° C warming target, we find that before the termination risk for SRM can be completely excluded, the acceptable greenhouse gas emission pathways remain only slightly higher than in scenarios without SRM. More generally, the uncertainties in SRM start time, acceptable magnitude and sustainability mean that it can be only a limited substitute to greenhouse gas (GHG) emission reductions. If an additional constraint for CO2 concentration to mitigate ocean acidification is included, the CO2 emissions need to be rapidly reduced even if strong SRM will become available. However, in such scenarios the reductions for other greenhouse gases are not needed to reach the 2 degree target. Therefore, we conclude that the needs to simultaneously mitigate ocean acidification and temperature increase have important implications on how climatic targets and policies in the presence of uncertain SRM should be framed.

In-wheel hub SRM simulation and analysis

NASA Astrophysics Data System (ADS)

Sager, Milton W., III

Is it feasible to replace the conventional gasoline engine and subsequent drive system in a motorcycle with an electric switched reluctance motor (SRM) by placing the SRM inside the rear wheel, thereby removing the need for things such as a clutch, chain, transmission, gears and sprockets? The goal of this thesis is to study the theoretical aspect of prototyping and analyzing an in-wheel electric hub motor to replace the standard gasoline engine traditionally found on motorcycles. With the recent push for clean energy, electric vehicles are becoming more common. All currently produced electric motorcycles use conventional, prefabricated electric motors connected to the traditional sprocket and chain design. This greatly restricts the efficiency and range of these motorcycles. My design stands apart by turning the rear wheel into a SRM which uses electromagnets around a non-magnetic core to convert electrical energy into mechanical force driving the rear wheel. To my knowledge, there is currently no motorcycle designed with an in-wheel hub SRM. A three-phase SRM and a five-phase SRM will be simulated and analyzed using MATLAB with Simulink. Factors such as friction, weight, power, etc. will be taken into account in order to create a realistic simulation as if it were inside the rear wheel of a motorcycle. Since time and finances will not allow for a full scale build, a scaled model three-phase SRM will be attempted for demonstration purposes.

Depth Distribution and Assembly of Sulfate-Reducing Microbial Communities in Marine Sediments of Aarhus Bay

PubMed Central

Jochum, Lara M.; Chen, Xihan; Lever, Mark A.; Loy, Alexander; Jørgensen, Bo Barker; Schramm, Andreas

2017-01-01

ABSTRACT Most sulfate-reducing microorganisms (SRMs) present in subsurface marine sediments belong to uncultured groups only distantly related to known SRMs, and it remains unclear how changing geochemical zones and sediment depth influence their community structure. We mapped the community composition and abundance of SRMs by amplicon sequencing and quantifying the dsrB gene, which encodes dissimilatory sulfite reductase subunit beta, in sediment samples covering different vertical geochemical zones ranging from the surface sediment to the deep sulfate-depleted subsurface at four locations in Aarhus Bay, Denmark. SRMs were present in all geochemical zones, including sulfate-depleted methanogenic sediment. The biggest shift in SRM community composition and abundance occurred across the transition from bioturbated surface sediments to nonbioturbated sediments below, where redox fluctuations and the input of fresh organic matter due to macrofaunal activity are absent. SRM abundance correlated with sulfate reduction rates determined for the same sediments. Sulfate availability showed a weaker correlation with SRM abundances and no significant correlation with the composition of the SRM community. The overall SRM species diversity decreased with depth, yet we identified a subset of highly abundant community members that persists across all vertical geochemical zones of all stations. We conclude that subsurface SRM communities assemble by the persistence of members of the surface community and that the transition from the bioturbated surface sediment to the unmixed sediment below is a main site of assembly of the subsurface SRM community. IMPORTANCE Sulfate-reducing microorganisms (SRMs) are key players in the marine carbon and sulfur cycles, especially in coastal sediments, yet little is understood about the environmental factors controlling their depth distribution. Our results suggest that macrofaunal activity is a key driver of SRM abundance and community structure in marine sediments and that a small subset of SRM species of high relative abundance in the subsurface SRM community persists from the sulfate-rich surface sediment to sulfate-depleted methanogenic subsurface sediment. More generally, we conclude that SRM communities inhabiting the subsurface seabed assemble by the selective survival of members of the surface community. PMID:28939599

We Don't Need a "Geoengineering" Research Program

NASA Astrophysics Data System (ADS)

Caldeira, K.

2011-12-01

Most approaches commonly labeled as 'geoengineering' can be divided into two categories: approaches that attempt to reduce the change in atmospheric composition caused by anthropogenic emissions (commonly labeled CDR, for Carbon Dioxide Removal), and approaches that attempt to reduce the change in climate caused by changes in atmospheric composition (commonly labeled SRM, for Sunlight Reflection Methods or Solar Radiation Management). CDR is relatively uncontroversial (apart from ocean fertilization), and the primary issues are typically cost, effectiveness, local environmental consequences, and verification. In contrast, SRM has provoked much controversy, because large-scale SRM deployments necessarily would affect everyone on this planet. Several proposals have been tabled for SRM-specific or geoengineering-specific research and governance structures, treating SRM or geoengineering research as a thing apart. We should instead view CDR and SRM research as part of a broader continuum of activities aimed at understanding Earth system dynamics and reducing risks associated with climate change. The scope of existing research efforts should be broadened so that CDR and SRM approaches are, at this stage in development, treated as an extension of what we are already doing. What is 'geoengineering research'? A primary need at this time is for expansion of scope of and funding for existing climate-related research efforts. For examples: Scientists studying the role of aerosols in clouds or stratospheric processes can expand the domain of concern to consider effects of intentionally introduced aerosols (and not just natural aerosols and aerosols we introduce as a byproduct of civilization's normal functioning). Scientists studying effects of land-surface change on global and regional climates can expand the domain of concern beyond inadvertent effects to consider effects of land-surface changes undertaken with the intent to affect these climates. Research programs aimed at removing carbon dioxide from power plant flue gases can be broadened to consider industrial approaches to remove carbon dioxide that has already been released to the atmosphere. There appears to be little need for new overarching research structures or institutions at this time for activities for which there are no plans for deployment. Defining the scope of reference of 'geoengineering' and related terms (eg, 'geoengineering experiment') is a linguistic distraction and a waste of time. We should focus instead on substantive issues of primary concern. If our goal is to reduce risk from scientific experiments, then let's develop approaches aimed at governing risky experiments. Governance efforts can be aimed at eliminating unjustified risk independently of whether some people might want to apply labels like 'geoengineering' to those activities. We do not need 'a geoengineering research program'. We need to expand existing research programs to consider a broader range of activities and conditions. We do not need efforts to govern 'geoengineering experiments' although we may need efforts to govern scientific experiments that pose unjustified risks. Let's focus on gaining knowledge and managing risks, and not let our brains be addled by emotionally-charged language.

Determination of (87)Sr/(86)Sr and δ(88/86)Sr ratios in plant materials using MC-ICP-MS.

PubMed

Liu, Hou-Chun; Chung, Chuan-Hsiung; You, Chen-Feng; Chiang, Yi-Hsuan

2016-01-01

A protocol for highly accurate and precise determination of Sr isotope ratios in plant materials, (87)Sr/(86)Sr and δ (88/86)Sr, by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) is presented in this study. An Eichrom Sr resin was used for matrix separation and an improved Zr empirical external normalization coupled with standard-sample bracketing method (Zr EEN-SSB) was applied to mass bias correction during Sr isotope MC-ICP-MS measurements. Potential influences of matrix elements, and polyatomic and isobaric interferences on the Sr isotopic determination were further evaluated using NIST SRM 987 Sr isotopic standard spiked with various amount of Ca, Mg, and Rb contents. Concentrations of Ca and Mg lower than 30 ng g(-1) or Rb < 2 ng g(-1) in 150 ng g(-1) Sr analyte were estimated to have only a minor effect on Sr isotope ratios determination. On the other hand, intensity differences between sample and standards (IntSample/IntStandards) represented a large δ (88/86)Sr deviation of <0.9 or >1.3, reflecting the significance of intensity bias attributed to different mass bias behavior. An apple leaf material, NIST SRM 1515, was adopted as the plant material for overall evaluation of sample digestion, matrix separation, and potential spectral interferences on the measurements of Sr isotope ratios. Our results suggest that the partially remaining organic compounds in the incomplete digestion would have a significant bias on the extraction chromatography procedure, resulting in sizable uncertainty in δ (88/86)Sr ratios. Thus, complete digestion of the organic-enriched materials is of great importance for efficiency assurance in matrix separation. Extraction chromatography works well for the total digested samples, where Ca, Mg, and Rb were efficiently removed. The obtained average (87)Sr/(86)Sr and δ (88/86)Sr values for the NIST SRM 1515 apple leaves are 0.71398 ± 0.00004 and 0.23 ± 0.03‰ (2SD, n = 10), respectively.

Block 2 Solid Rocket Motor (SRM) conceptual design study. Volume 1: Appendices

NASA Technical Reports Server (NTRS)

1986-01-01

The design studies task implements the primary objective of developing a Block II Solid Rocket Motor (SRM) design offering improved flight safety and reliability. The SRM literature was reviewed. The Preliminary Development and Validation Plan is presented.

Mass spectrometry-based quantitation of Her2 in gastroesophageal tumor tissue: Comparison to IHC and FISH

PubMed Central

Catenacci, Daniel V.T.; Liao, Wei-Li; Zhao, Lei; Whitcomb, Emma; Henderson, Les; O’Day, Emily; Xu, Peng; Thyparambil, Sheeno; Krizman, David; Bengali, Kathleen; Uzzell, Jamar; Darfler, Marlene; Cecchi, Fabiola; Blackler, Adele; Bang, Yung-Jue; Hart, John; Xiao, Shu-Yuan; Lee, Sang Mee; Burrows, Jon; Hembrough, Todd

2015-01-01

Background Trastuzumab showed survival benefit for Her2-positive gastroesophageal cancers (GEC). Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) currently determine eligibility for trastuzumab-based therapy. However, these low-throughput assays often produce discordant or equivocal results. Methods We developed a targeted proteomic assay based on selected reaction monitoring mass spectrometry (SRM-MS) and quantified levels (amol/ug) of Her2-SRM protein in cell lines (n=27) and GEC tissues (n=139). We compared Her2-SRM protein expression with IHC/FISH, seeking to determine optimal SRM protein expression cut-offs to identify HER2 gene amplification. Results After demonstrating assay development, precision, and stability, Her2-SRM protein measurement was observed to be highly concordant with HER2/CEP17 ratio, particularly in a multivariate regression model adjusted for SRM-expression of Met, Egfr, Her3, and HER2-heterogeneity covariates, and their interactions (cell lines r2=0.9842; FFPE r2=0.7643). In GEC tissues, Her2-SRM protein was detected in 71.2% of cases. ROC curves demonstrated Her2-SRM protein levels to have high specificity (100%) at an upper-level cut-off of >750 amol/μg and sensitivity (75%) at lower-level cut-off of <450 amol/ug to identify HER2 FISH amplified tumors. An ‘equivocal-zone’ of 450-750 amol/ug of Her2-SRM protein was analogous to ’IHC2+#x2019;, but represented fewer cases (9-16% of cases versus 36-41%). Conclusions Compared to IHC, targeted SRM-Her2 proteomics provided more objective and quantitative Her2 expression with excellent HER2/CEP17 FISH correlation and fewer equivocal cases. Along with the multiplex capability for other relevant oncoproteins, these results demonstrated a refined HER2 protein expression assay for clinical application. PMID:26581548

Horizontally scaling dChache SRM with the Terracotta platform

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

Perelmutov, T.; Crawford, M.; Moibenko, A.

2011-01-01

The dCache disk caching file system has been chosen by a majority of LHC experiments Tier 1 centers for their data storage needs. It is also deployed at many Tier 2 centers. The Storage Resource Manager (SRM) is a standardized grid storage interface and a single point of remote entry into dCache, and hence is a critical component. SRM must scale to increasing transaction rates and remain resilient against changing usage patterns. The initial implementation of the SRM service in dCache suffered from an inability to support clustered deployment, and its performance was limited by the hardware of a singlemore » node. Using the Terracotta platform, we added the ability to horizontally scale the dCache SRM service to run on multiple nodes in a cluster configuration, coupled with network load balancing. This gives site administrators the ability to increase the performance and reliability of SRM service to face the ever-increasing requirements of LHC data handling. In this paper we will describe the previous limitations of the architecture SRM server and how the Terracotta platform allowed us to readily convert single node service into a highly scalable clustered application.« less

Monofluorophosphate is a selective inhibitor of respiratory sulfate-reducing microorganisms.

PubMed

Carlson, Hans K; Stoeva, Magdalena K; Justice, Nicholas B; Sczesnak, Andrew; Mullan, Mark R; Mosqueda, Lorraine A; Kuehl, Jennifer V; Deutschbauer, Adam M; Arkin, Adam P; Coates, John D

2015-03-17

Despite the environmental and economic cost of microbial sulfidogenesis in industrial operations, few compounds are known as selective inhibitors of respiratory sulfate reducing microorganisms (SRM), and no study has systematically and quantitatively evaluated the selectivity and potency of SRM inhibitors. Using general, high-throughput assays to quantitatively evaluate inhibitor potency and selectivity in a model sulfate-reducing microbial ecosystem as well as inhibitor specificity for the sulfate reduction pathway in a model SRM, we screened a panel of inorganic oxyanions. We identified several SRM selective inhibitors including selenate, selenite, tellurate, tellurite, nitrate, nitrite, perchlorate, chlorate, monofluorophosphate, vanadate, molydate, and tungstate. Monofluorophosphate (MFP) was not known previously as a selective SRM inhibitor, but has promising characteristics including low toxicity to eukaryotic organisms, high stability at circumneutral pH, utility as an abiotic corrosion inhibitor, and low cost. MFP remains a potent inhibitor of SRM growing by fermentation, and MFP is tolerated by nitrate and perchlorate reducing microorganisms. For SRM inhibition, MFP is synergistic with nitrite and chlorite, and could enhance the efficacy of nitrate or perchlorate treatments. Finally, MFP inhibition is multifaceted. Both inhibition of the central sulfate reduction pathway and release of cytoplasmic fluoride ion are implicated in the mechanism of MFP toxicity.

Rapid and reversible impairments of short- and long-term social recognition memory are caused by acute isolation of adult rats via distinct mechanisms.

PubMed

Shahar-Gold, Hadar; Gur, Rotem; Wagner, Shlomo

2013-01-01

Mammalian social organizations require the ability to recognize and remember individual conspecifics. This social recognition memory (SRM) can be examined in rodents using their innate tendency to investigate novel conspecifics more persistently than familiar ones. Here we used the SRM paradigm to examine the influence of housing conditions on the social memory of adult rats. We found that acute social isolation caused within few days a significant impairment in acquisition of short-term SRM of male and female rats. Moreover, SRM consolidation into long-term memory was blocked following only one day of social isolation. Both impairments were reversible, but with different time courses. Furthermore, only the impairment in SRM consolidation was reversed by systemic administration of arginine-vasopressin (AVP). In contrast to SRM, object recognition memory was not affected by social isolation. We conclude that acute social isolation rapidly induces reversible changes in the brain neuronal and molecular mechanisms underlying SRM, which hamper its acquisition and completely block its consolidation. These changes occur via distinct, AVP sensitive and insensitive mechanisms. Thus, acute social isolation of rats swiftly causes changes in their brain and interferes with their normal social behavior.

Block 2 Solid Rocket Motor (SRM) conceptual design study, volume 1

NASA Technical Reports Server (NTRS)

1986-01-01

Segmented and monolithic Solid Rocket Motor (SRM) design concepts were evaluated with emphasis on joints and seals. Particular attention was directed to eliminating deficiencies in the SRM High Performance Motor (HPM). The selected conceptual design is described and discussed.

The Snowmelt-Runoff Model (SRM) user's manual

NASA Technical Reports Server (NTRS)

Martinec, J.; Rango, A.; Major, E.

1983-01-01

A manual to provide a means by which a user may apply the snowmelt runoff model (SRM) unaided is presented. Model structure, conditions of application, and data requirements, including remote sensing, are described. Guidance is given for determining various model variables and parameters. Possible sources of error are discussed and conversion of snowmelt runoff model (SRM) from the simulation mode to the operational forecasting mode is explained. A computer program is presented for running SRM is easily adaptable to most systems used by water resources agencies.

Long-Gradient Separations Coupled with Selected Reaction Monitoring for Highly Sensitive, Large Scale Targeted Protein Quantification in a Single Analysis

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

Shi, Tujin; Fillmore, Thomas L.; Gao, Yuqian

2013-10-01

Long-gradient separations coupled to tandem MS were recently demonstrated to provide a deep proteome coverage for global proteomics; however, such long-gradient separations have not been explored for targeted proteomics. Herein, we investigate the potential performance of the long-gradient separations coupled with selected reaction monitoring (LG-SRM) for targeted protein quantification. Direct comparison of LG-SRM (5 h gradient) and conventional LC-SRM (45 min gradient) showed that the long-gradient separations significantly reduced background interference levels and provided an 8- to 100-fold improvement in LOQ for target proteins in human female serum. Based on at least one surrogate peptide per protein, an LOQ ofmore » 10 ng/mL was achieved for the two spiked proteins in non-depleted human serum. The LG-SRM detection of seven out of eight endogenous plasma proteins expressed at ng/mL or sub-ng/mL levels in clinical patient sera was also demonstrated. A correlation coefficient of >0.99 was observed for the results of LG-SRM and ELISA measurements for prostate-specific antigen (PSA) in selected patient sera. Further enhancement of LG-SRM sensitivity was achieved by applying front-end IgY14 immunoaffinity depletion. Besides improved sensitivity, LG-SRM offers at least 3 times higher multiplexing capacity than conventional LC-SRM due to ~3-fold increase in average peak widths for a 300-min gradient compared to a 45-min gradient. Therefore, LG-SRM holds great potential for bridging the gap between global and targeted proteomics due to its advantages in both sensitivity and multiplexing capacity.« less

A Computational Tool to Detect and Avoid Redundancy in Selected Reaction Monitoring

PubMed Central

Röst, Hannes; Malmström, Lars; Aebersold, Ruedi

2012-01-01

Selected reaction monitoring (SRM), also called multiple reaction monitoring, has become an invaluable tool for targeted quantitative proteomic analyses, but its application can be compromised by nonoptimal selection of transitions. In particular, complex backgrounds may cause ambiguities in SRM measurement results because peptides with interfering transitions similar to those of the target peptide may be present in the sample. Here, we developed a computer program, the SRMCollider, that calculates nonredundant theoretical SRM assays, also known as unique ion signatures (UIS), for a given proteomic background. We show theoretically that UIS of three transitions suffice to conclusively identify 90% of all yeast peptides and 85% of all human peptides. Using predicted retention times, the SRMCollider also simulates time-scheduled SRM acquisition, which reduces the number of interferences to consider and leads to fewer transitions necessary to construct an assay. By integrating experimental fragment ion intensities from large scale proteome synthesis efforts (SRMAtlas) with the information content-based UIS, we combine two orthogonal approaches to create high quality SRM assays ready to be deployed. We provide a user friendly, open source implementation of an algorithm to calculate UIS of any order that can be accessed online at http://www.srmcollider.org to find interfering transitions. Finally, our tool can also simulate the specificity of novel data-independent MS acquisition methods in Q1–Q3 space. This allows us to predict parameters for these methods that deliver a specificity comparable with that of SRM. Using SRM interference information in addition to other sources of information can increase the confidence in an SRM measurement. We expect that the consideration of information content will become a standard step in SRM assay design and analysis, facilitated by the SRMCollider. PMID:22535207

Long-term social recognition memory is mediated by oxytocin-dependent synaptic plasticity in the medial amygdala.

PubMed

Gur, Rotem; Tendler, Alex; Wagner, Shlomo

2014-09-01

Recognition of specific individuals is fundamental to mammalian social behavior and is mediated in most mammals by the main and accessory olfactory systems. Both these systems innervate the medial amygdala (MeA), where activity of the neuropeptide oxytocin is thought to mediate social recognition memory (SRM). The specific contribution of the MeA to SRM formation and the specific actions of oxytocin in the MeA are unknown. We used the social discrimination test to evaluate short-term and long-term SRM in adult Sprague-Dawley male rats (n = 38). The role of protein synthesis in the MeA was investigated by local application of the protein synthesis blocker anisomycin (n = 11). Synaptic plasticity was assessed in vivo by recording the MeA evoked field potential responses to stimulation of the main (n = 21) and accessory (n = 56) olfactory bulbs before and after theta burst stimulation. Intracerebroventricular administration of saline, oxytocin, or oxytocin receptor antagonist was used to measure the effect of oxytocin on synaptic plasticity. Anisomycin application to the MeA prevented the formation of long-term SRM. In addition, the responses of MeA neurons underwent long-term depression (LTD) after theta burst stimulation of the accessory olfactory bulb, but not the main accessory bulb, in an oxytocin-dependent manner. No LTD was found in socially isolated rats, which are known to lack long-term SRM. Finally, accessory olfactory bulb stimulation before SRM acquisition blocked long-term SRM, supporting the involvement of LTD in the MeA in formation of long-term SRM. Our results indicate that long-term SRM in rats involves protein synthesis and oxytocin-dependent LTD in the MeA. Copyright © 2014 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Selected reaction monitoring mass spectrometry: a methodology overview.

PubMed

Ebhardt, H Alexander

2014-01-01

Moving past the discovery phase of proteomics, the term targeted proteomics combines multiple approaches investigating a certain set of proteins in more detail. One such targeted proteomics approach is the combination of liquid chromatography and selected or multiple reaction monitoring mass spectrometry (SRM, MRM). SRM-MS requires prior knowledge of the fragmentation pattern of peptides, as the presence of the analyte in a sample is determined by measuring the m/z values of predefined precursor and fragment ions. Using scheduled SRM-MS, many analytes can robustly be monitored allowing for high-throughput sample analysis of the same set of proteins over many conditions. In this chapter, fundaments of SRM-MS are explained as well as an optimized SRM pipeline from assay generation to data analyzed.

Effect of 25(OH) vitamin D reference method procedure (RMP) alignment on clinical measurements obtained with the IDS-iSYS chemiluminescent-based automated analyzer.

PubMed

Simpson, Christine A; Cusano, Anna Maria; Bihuniak, Jessica; Walker, Joanne; Insogna, Karl L

2015-04-01

The Vitamin D Standardization Program (VDSP) has identified ID-LC/MS/MS as the reference method procedure (RMP) for 25(OH) vitamin D and NIST Standard SRM2972 as the standard reference material (SRM). As manufacturers align their products to the RMP and NIST standard, a concern is that results obtained in aligned assays will be divergent from those obtained with pre-alignment assays. The Immunodiagnostic Systems Ltd., chemiluminescent, 25(OH) vitamin D iSYS platform assay, was recently harmonized to the RMP. To determine the impact of standardization on results obtained with iSYS reagents, 119 single donor serum samples from eight different disease categories were analyzed in four non-standardized and two standardized iSYS assays. There were strong correlations between the four non-standardized and two standardized assays with Spearman's rank r values between 0.975 and 0.961 and four of the eight r values were >0.97. R(2) values for the eight best-fit linear regression equations ranging between 0.947 and 0.916. None of the slopes were found to be significantly different from one another. Bland-Altman plots showed that the bias was comparable when each of the four non-standardized assays was compared to either of the standardized assays. When the data were segregated in values between 6 and 49ng/mL (15-122nmol/L) or between 50 and 100ng/mL (125-250nmol/L) significant associations remained between results obtained with non-standardized and standardized calibrators regardless of the absolute value. When five recent DEQAS unknowns were analyzed in one non-standardized and one standardized assay the mean percent difference from the NIST target in values obtained using standardized vs. non-standardized calibrators were not significantly different. Finally, strong and statistically significant associations between the results were obtained using non-standardized and standardized assays for six of eight clinical conditions. The only exceptions were hypocalcemia and breast cancer, which likely reflect the small sample sizes for each of these diseases. These initial data provide confidence that the move to a NIST standardized assay will have little impact on results obtained with the iSYS platform. This article is part of a Special Issue entitled '17th Vitamin D Workshop'. Copyright © 2014 Elsevier Ltd. All rights reserved.

Block 2 SRM conceptual design studies. Volume 1, Book 2: Preliminary development and verification plan

NASA Technical Reports Server (NTRS)

1986-01-01

Activities that will be conducted in support of the development and verification of the Block 2 Solid Rocket Motor (SRM) are described. Development includes design, fabrication, processing, and testing activities in which the results are fed back into the project. Verification includes analytical and test activities which demonstrate SRM component/subassembly/assembly capability to perform its intended function. The management organization responsible for formulating and implementing the verification program is introduced. It also identifies the controls which will monitor and track the verification program. Integral with the design and certification of the SRM are other pieces of equipment used in transportation, handling, and testing which influence the reliability and maintainability of the SRM configuration. The certification of this equipment is also discussed.

On the effect of grain burnback on STS-SRM fragment velocity

NASA Astrophysics Data System (ADS)

Eck, Marshall B.; Mukunda, Meera

Concerns raised during the Ulysses Final Safety Analysis Review (FSAR) process called the solid rocket motor (SRM) fragment velocity prediction model into question. The specific area of concern was that there was a section of the SRM casing which was exposed to SRM chamber pressure as the grain (fuel) was consumed. These questions centered on the velocity of fragments which originated from the field joint region given that failure occurred between 37 and 72 seconds mission elapsed time (MET). Two dimensional coupled Eulerian-Lagrangian calculations were performed to assess the hot gas flow field which resulted from SRM casing fragmentation. The fragment to gas interface-pressure time-history obtained from these analyses was reduced to a boundary condition algorithm which was applied to an explicit-time-integration, finite element, three dimensional shell model of the SRM casing and unburned fuel. The results of these calculations showed that the velocity of fragments originating in the field joint was adequately described by the range of velocities given in the Shuttle Data Book (1988). Based on these results, no further analyses were required, and approval was obtained from the Launch Abort Subpanel of the Interagency Nuclear Safety Review Panel to use the SRM fragment velocity environments presented in the Ulysses FSAR (1990).

On the effect of grain burnback on STS-SRM fragment velocity

NASA Astrophysics Data System (ADS)

Eck, Marshall B.; Mukunda, Meera

1991-01-01

Concerns raised during the Ulysses Final Safety Analysis Review (FSAR) process called the solid rocket motor (SRM) fragment velocity prediction model into question. The specific area of concern was that there was a section of the SRM casing which was exposed to SRM chamber pressure as the grain (fuel) was consumed. These questions centered on the velocity of fragments which originated from the field joint region given that failure occurred between 37 and 72 seconds mission elapsed time (MET). Two dimensional coupled Eulerian-Lagrangian calculations were performed to assess the hot gas flow field which resulted from SRM casing fragmentation. The fragment to gas interface-pressure time-history obtained from these analyses was reduced to a boundary condition algorithm which was applied to an explicit-time-integration, finite element, three dimensional shell model of the SRM casing and unburned fuel. The results of these calculations showed that the velocity of fragments originating in the field joint was adequately described by the range of velocities given in the Shuttle Data Book (1988). Based on these results, no further analyses were required, and approval was obtained from the Launch Abort Subpanel of the Interagency Nuclear Safety Review Panel to use the SRM fragment velocity environments presented in the Ulysses FSAR (1990).

Space Shuttle solid rocket booster

NASA Technical Reports Server (NTRS)

Hardy, G. B.

1979-01-01

Details of the design, operation, testing and recovery procedures of the reusable solid rocket boosters (SRB) are given. Using a composite PBAN propellant, they will provide the primary thrust (six million pounds maximum at 20 s after ignition) within a 3 g acceleration constraint, as well as thrust vector control for the Space Shuttle. The drogues were tested to a load of 305,000 pounds, and the main parachutes to 205,000. Insulation in the solid rocket motor (SRM) will be provided by asbestos-silica dioxide filled acrylonitrile butadiene rubber ('asbestos filled NBR') except in high erosion areas (principally in the aft dome), where a carbon-filled ethylene propylene diene monomer-neopreme rubber will be utilized. Furthermore, twenty uses for the SRM nozzle will be allowed by its ablative materials, which are principally carbon cloth and silica cloth phenolics.

Elastomeric Thermal Insulation Design Considerations in Long, Aluminized Solid Rocket Motors

NASA Technical Reports Server (NTRS)

Martin, Heath T.

2017-01-01

An all-new sounding rocket was designed at NASA's Marshall Space Flight Center that featured an aft finocyl, aluminized solid propellant grain and silica-filled ethylene-propylene-diene monomer (SFEPDM) internal insulation. Upon the initial static firing of the first of this new design, the solid rocket motor (SRM) case failed thermally just upstream of the aft closure early in the burn time. Subsequent fluid modeling indicated that the high-velocity combustion-product jets emanating from the fin-slots in the propellant grain were likely inducing a strongly swirling flow, thus substantially increasing the severity of the convective environment on the exposed portion of the SFEPDM insulation in this region. The aft portion of the fin-slots in another of the motors were filled with propellant to eliminate the possibility of both direct jet impingement on the exposed SFEPDM and the appearance of strongly swirling flow in the aft region of the motor. When static-fired, this motor's case still failed in the same axial location, and, though somewhat later than for the first static firing, still in less than 1/3rd of the desired burn duration. These results indicate that the extreme material decomposition rates of the SFEPDM in this application are not due to gas-phase convection or shear but rather to interactions with burning aluminum or alumina slag. Further comparisons with between SFEPDM performance in this design and that in other hot-fire tests provide insight into the mechanisms of SFEPDM decomposition in SRM aft domes that can guide the upcoming redesign effort, as well as other future SRM designs. These data also highlight the current limitations of modeling elastomeric insulators solely with diffusion-controlled, gas-phase thermochemistry in SRM regions with significant viscous shear and/or condense-phase impingement or flow.

Temperature-dependent instability of the cTnI subunit in NIST SRM2921 characterized by tryptic peptide mapping.

PubMed

van der Burgt, Yuri E M; Cobbaert, Christa M; Dalebout, Hans; Smit, Nico; Deelder, André M

2012-08-01

In this study temperature-dependent instability of the cTnI subunit of the three-protein complex NIST SRM2921 was demonstrated using a mass spectrometric tryptic peptide mapping approach. The results were compared to the cTnI subunit obtained as a protein standard from Calbiochem with identical amino acid sequence. Both the three-protein complex from NIST as well as the cTnI subunit were incubated at elevated temperatures and then evaluated with respect to the primary sequence. The corresponding peptide maps were analyzed using LC-MS/MS. From a Mascot database search in combination with "semiTrypsin" tolerance it was found that two peptide backbone cleavages had occurred in subunit cTnI in NIST SRM2921 material upon incubation at 37°C, namely between amino acids at 148/149 and 194/195. The Calbiochem standard did not show increased levels of "unexpected" peptides in tryptic peptide maps. One of the two peptide backbone cleavages could also be monitored using a "single-step" MALDI-MS approach, i.e. without the need for peptide separation. The amount of degradation appeared rather constant in replicate temperature-instability experiments. However, for accurate quantification internal labelled standards are needed. Copyright © 2012 Elsevier B.V. All rights reserved.

Asymmetric transmission and optical low-pass filtering in a stack of random media with graded transport mean free path

NASA Astrophysics Data System (ADS)

Bingi, J.; Hemalatha, M.; Anita, R. W.; Vijayan, C.; Murukeshan, V. M.

2015-11-01

Light transport and the physical phenomena related to light propagation in random media are very intriguing, they also provide scope for new paradigms of device functionality, most of which remain unexplored. Here we demonstrate, experimentally and by simulation, a novel kind of asymmetric light transmission (diffusion) in a stack of random media (SRM) with graded transport mean free path. The structure is studied in terms of transmission, of photons propagated through and photons generated within the SRM. It is observed that the SRM exhibits asymmetric transmission property with a transmission contrast of 0.25. In addition, it is shown that the SRM works as a perfect optical low-pass filter with a well-defined cutoff wavelength at 580 nm. Further, the photons generated within the SRM found to exhibit functionality similar to an optical diode with a transmission contrast of 0.62. The basis of this functionality is explained in terms of wavelength dependent photon randomization and the graded transport mean free path of SRM.

Psychophysiological effects of self-regulation method: EEG frequency analysis and contingent negative variations.

PubMed

Ikemi, A

1988-01-01

Experiments were conducted to investigate the psychophysiological effects of self-regulation method (SRM), a newly developed method of self-control, using EEG frequency analysis and contingent negative variations (CNV). The results of the EEG frequency analysis showed that there is a significant increase in the percentage (power) of the theta-band and a significant decrease in the percentage (power) of the beta-band during SRM. Moreover, the results of an identical experiment conducted on subjects in a drowsy state showed that the changes in EEG frequencies during SRM can be differentiated from those of a drowsy state. Furthermore, experiments using CNV showed that there is a significant reduction of CNV amplitude during SRM. Despite the reduced amplitude during SRM, the number of errors in a task to evoke the CNV was reduced significantly without significant delay of reaction time. When an identical experiment was conducted in a drowsy state, CNV amplitude was reduced significantly, but reaction time and errors increased. From these experiments, the state of vigilance during SRM was discussed as a state of 'relaxed alertness'.

Determination of arsenic and cadmium in crude oil by direct sampling graphite furnace atomic absorption spectrometry

NASA Astrophysics Data System (ADS)

de Jesus, Alexandre; Zmozinski, Ariane Vanessa; Damin, Isabel Cristina Ferreira; Silva, Márcia Messias; Vale, Maria Goreti Rodrigues

2012-05-01

In this work, a direct sampling graphite furnace atomic absorption spectrometry method has been developed for the determination of arsenic and cadmium in crude oil samples. The samples were weighed directly on the solid sampling platforms and introduced into the graphite tube for analysis. The chemical modifier used for both analytes was a mixture of 0.1% Pd + 0.06% Mg + 0.06% Triton X-100. Pyrolysis and atomization curves were obtained for both analytes using standards and samples. Calibration curves with aqueous standards could be used for both analytes. The limits of detection obtained were 5.1 μg kg- 1 for arsenic and 0.2 μg kg- 1 for cadmium, calculated for the maximum amount of sample that can be analyzed (8 mg and 10 mg) for arsenic and cadmium, respectively. Relative standard deviations lower than 20% were obtained. For validation purposes, a calibration curve was constructed with the SRM 1634c and aqueous standards for arsenic and the results obtained for several crude oil samples were in agreement according to paired t-test. The result obtained for the determination of arsenic in the SRM against aqueous standards was also in agreement with the certificate value. As there is no crude oil or similar reference material available with a certified value for cadmium, a digestion in an open vessel under reflux using a "cold finger" was adopted for validation purposes. The use of paired t-test showed that the results obtained by direct sampling and digestion were in agreement at a 95% confidence level. Recovery tests were carried out with inorganic and organic standards and the results were between 88% and 109%. The proposed method is simple, fast and reliable, being appropriated for routine analysis.

Determination of copper and mercury in phosphate fertilizers employing direct solid sampling analysis and high resolution continuum source graphite furnace atomic absorption spectrometry

NASA Astrophysics Data System (ADS)

de Oliveira Souza, Sidnei; François, Luciane Luiza; Borges, Aline Rocha; Vale, Maria Goreti Rodrigues; Araujo, Rennan Geovanny Oliveira

2015-12-01

The present study proposes the determination of copper and mercury in phosphate fertilizers by direct solid sampling analysis (SS) employing high resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS). For Cu determination, two analytical lines were used: 327.3960 nm and 249.2146 nm. Hg determination was carried out on the line 253.6521 nm and 100 μg KMnO4 was used as chemical modifier. The optimal pyrolysis temperature for Cu determination was 1300 °C. Atomization temperatures for Cu and Hg were 2400 and 1100 °C, respectively. External calibration with aqueous standard solutions was adopted for both elements. The limits of quantification (LoQs) and characteristic mass (m0) obtained for Cu determination were 0.4 μg g- 1 and 1.12 ng, respectively, on line 249.2146 nm, and 64 μg g- 1 and 25 pg on 327.3960 nm. For mercury, LoQ and m0 were 4.8 ng g- 1 and 39 pg, respectively. The accuracy of the proposed methods was confirmed by the analysis of standard reference material (SRM) of Trace Elements in Multi-Nutrient Fertilizer (SRM NIST 695). The precision expressed as relative standard deviation (RSD), was better than 8.2% for Hg and 7.7% for the Cu (n = 5), considered satisfactory for microanalysis in solid sample. Four fertilizer samples acquired in commercial establishments in the city of Salvador, Bahia, Brazil, were analyzed. The optimized analytical methods were simple, fast, accurate, precise and free of spectral interferences for the determination of Cu and Hg in phosphate fertilizer samples by SS-HR-CS GF AAS, avoiding the dissolution of the sample, the use of harmful reagents and the generation of residues.

Comparison of four USEPA digestion methods for trace metal analysis using certified and Florida soils

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

Chen, M.; Ma, L.Q.

1998-11-01

It is critical to compare existing sample digestion methods for evaluating soil contamination and remediation. USEPA Methods 3050, 3051, 3051a, and 3052 were used to digest standard reference materials and representative Florida surface soils. Fifteen trace metals (Ag, As, Ba, Be, Cd, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Se, and Za), and six macro elements (Al, Ca, Fe, K, Mg, and P) were analyzed. Precise analysis was achieved for all elements except for Cd, Mo, Se, and Sb in NIST SRMs 2704 and 2709 by USEPA Methods 3050 and 3051, and for all elements except for As, Mo,more » Sb, and Se in NIST SRM 2711 by USEPA Method 3052. No significant differences were observed for the three NIST SRMs between the microwave-assisted USEPA Methods 3051 and 3051A and the conventional USEPA Method 3050 Methods 3051 and 3051a and the conventional USEPA Method 3050 except for Hg, Sb, and Se. USEPA Method 3051a provided comparable values for NIST SRMs certified using USEPA Method 3050. However, for method correlation coefficients and elemental recoveries in 40 Florida surface soils, USEPA Method 3051a was an overall better alternative for Method 3050 than was Method 3051. Among the four digestion methods, the microwave-assisted USEPA Method 3052 achieved satisfactory recoveries for all elements except As and Mg using NIST SRM 2711. This total-total digestion method provided greater recoveries for 12 elements Ag, Be, Cr, Fe, K, Mn, Mo, Ni, Pb, Sb, Se, and Zn, but lower recoveries for Mg in Florida soils than did the total-recoverable digestion methods.« less

Determination of egg proteins in snack food and noodles.

PubMed

Williams, Kristina M; Westphal, Carmen D; Shriver-Lake, Lisa C

2004-01-01

Egg is one of the 5 major allergenic foods that are responsible for more than 3/4 of food allergies in children. Food-allergic responses can be controlled by avoidance of the offending foods. The applicability of a commercial enzyme-linked immunosorbent assay (ELISA) kit for the detection of egg in food products such as cookies, crackers, pretzels, salad dressings, and raw and cooked noodles was evaluated. A preliminary evaluation of an antibody-based biosensor was also performed. A National Institute of Standards and Technology (NIST) whole dried egg powder reference material, SRM 8415, was used as a standard. A homogeneous and stable aqueous egg suspension was prepared for the evaluation of the performance of the Veratox for Egg Allergen Test (Neogen Corp., Lansing, MI). This test does not detect egg yolk proteins. Each gram of the aqueous dried egg suspension contained 643 microg whole dried egg, 0.5 mg thimerosal, and 2.5 mg bovine serum albumin. When cookies, crackers, salad dressings, noodles, and ice cream were spiked at a level of 24 mg/kg SRM 8415, recoveries for whole egg averaged about 28%. All foods containing egg as indicated on the ingredient label were found positive by the Veratox test. No false positives occurred in samples that did not contain eggs. Similar results were obtained using the Naval Research Laboratory (NRL) array biosensor, an evanescent wave fluoroimmunosensor. Results for cooked noodles showed that they contained <1% of the egg found in uncooked noodles. A comparison of extracts from cooked and uncooked noodles by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed differences in protein profiles. The boiling of the noodles could have reduced the immunoreactivity of the egg proteins to the antibodies used in the kit or rendered the egg proteins nonextractable.

Cyanovanadate(III) complexes as novel additives for efficient generation of volatile cadmium species in complex samples prior to determinations by inductively coupled plasma mass spectrometry (ICP-MS)

PubMed Central

Yilmaz, Vedat; Arslan, Zikri; Rose, LaKeysha; Little, Maria D.

2013-01-01

A new method has been described for generation of volatile species of Cd using vanadium(III) cyanide complex. Aqueous solutions of 0.04 mol L−1 vanadium chloride (VCl3) and 0.12 mol L−1 potassium cyanide (KCN) were reacted on-line yielding a suspension of vanadium hydroxide, V(OH)3. This suspension was dissolved along the stream of sample solution in dilute HCl to form heptacyanovanadate(III) complex, [V(CN)7]4−. Volatile Cd species were generated by reacting the stream of sample solution and cyanovanadate(III) complex with sodium borohydride (NaBH4). Feasibility of off-line and on-online approaches was investigated for quantitative determinations. Better precision and daily stability were achieved with on-line settings. Optimum signals were obtained from sample solutions within a range of 3 to 5% v/v HCl. A concentration of 2% m/v NaBH4 was adequate to achieve an enhancement of 20-fold in the presence of cyanovanadate(III) complex. The limits of detection were 5.0 and 4.5 ng L−1 for 110Cd and 111Cd isotopes, respectively. Precision (%RSD) was better than 4.7% for six replicate measurements. The interferences of Cu(II) and Ni(II) were marginal (<10%) at 1.0 μg mL−1. Depressive effects from Bi, Se and Sn were not significant below 0.1 μg mL−1. The method was validated by determination of Cd using ICP-MS in certified reference materials of Nearshore seawater (CASS-4), Bone ash (SRM 1400), Dogfish liver (DOLT-4) and Mussel tissue (SRM 2976). PMID:24014893

An assessment of 25-hydroxyvitamin D measurements in comparability studies conducted by the Vitamin D Metabolites Quality Assurance Program.

PubMed

Bedner, Mary; Lippa, Katrice A; Tai, Susan S-C

2013-11-15

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health Office of Dietary Supplements, established the first accuracy-based program for improving the comparability of vitamin D metabolite measurements, the Vitamin D Metabolites Quality Assurance Program. The study samples were human serum or plasma Standard Reference Materials (SRMs) with 25-hydroxyvitamin D values that were determined at NIST. Participants evaluated the materials using immunoassay (IA), liquid chromatography (LC) with mass spectrometric detection, and LC with ultraviolet absorbance detection. NIST evaluated the results for concordance within the participant community as well as trueness relative to the NIST value. For the study materials that contain mostly 25-hydroxyvitamin D3 (25(OH)D3),the coefficient of variation (CV) for the participant results was consistently in the range from 7% to 19%, and the median values were biased high relative to the NIST values. However, for materials that contain significant concentrations of both 25-hydroxyvitamin D2 (25(OH)D2) and 25(OH)D3, the median IA results were biased lower than both the LC and the NIST values, and the CV was as high as 28%. The first interlaboratory comparison results for SRM 972a Vitamin D Metabolites in Human Serum are also reported. Relatively large within-lab and between-lab variability hinders conclusive assessments of bias and accuracy. © 2013.

Regularity of daily life in relation to personality, age, gender, sleep quality and circadian rhythms

NASA Technical Reports Server (NTRS)

Monk, T. H.; Petrie, S. R.; Hayes, A. J.; Kupfer, D. J.

1994-01-01

A diary-like instrument to measure lifestyle regularity (the 'Social Rhythm Metric'-SRM) was given to 96 subjects (48 women, 48 men), 39 of whom repeated the study after at least one year, with additional objective measures of rest/activity. Lifestyle regularity as measured by the SRM related to age, morningness, subjective sleep quality and time-of-day variations in alertness, but not to gender, extroversion or neuroticism. Statistically significant test-retest correlations of about 0.4 emerged for SRM scores over the 12-30 month delay. Diary-based estimates of bedtime and waketime appeared fairly reliable. In a further study of healthy young men, 4 high SRM scorers ('regular') had a deeper nocturnal body temperature trough than 5 low SRM scorers ('irregular'), suggesting a better functioning circadian system in the 'regular' group.

Snowmelt-runoff Model Utilizing Remotely-sensed Data

NASA Technical Reports Server (NTRS)

Rango, A.

1985-01-01

Remotely sensed snow cover information is the critical data input for the Snowmelt-Runoff Model (SRM), which was developed to simulatke discharge from mountain basins where snowmelt is an important component of runoff. Of simple structure, the model requires only input of temperature, precipitation, and snow covered area. SRM was run successfully on two widely separated basins. The simulations on the Kings River basin are significant because of the large basin area (4000 sq km) and the adequate performance in the most extreme drought year of record (1976). The performance of SRM on the Okutadami River basin was important because it was accomplished with minimum snow cover data available. Tables show: optimum and minimum conditions for model application; basin sizes and elevations where SRM was applied; and SRM strengths and weaknesses. Graphs show results of discharge simulation.

Stratospheric Aerosols for Solar Radiation Management

NASA Astrophysics Data System (ADS)

Kravitz, Ben

SRM in the context of this entry involves placing a large amount of aerosols in the stratosphere to reduce the amount of solar radiation reaching the surface, thereby cooling the surface and counteracting some of the warming from anthropogenic greenhouse gases. The way this is accomplished depends on the specific aerosol used, but the basic mechanism involves backscattering and absorbing certain amounts of solar radiation aloft. Since warming from greenhouse gases is due to longwave (thermal) emission, compensating for this warming by reduction of shortwave (solar) energy is inherently imperfect, meaning SRM will have climate effects that are different from the effects of climate change. This will likely manifest in the form of regional inequalities, in that, similarly to climate change, some regions will benefit from SRM, while some will be adversely affected, viewed both in the context of present climate and a climate with high CO2 concentrations. These effects are highly dependent upon the means of SRM, including the type of aerosol to be used, the particle size and other microphysical concerns, and the methods by which the aerosol is placed in the stratosphere. SRM has never been performed, nor has deployment been tested, so the research up to this point has serious gaps. The amount of aerosols required is large enough that SRM would require a major engineering endeavor, although SRM is potentially cheap enough that it could be conducted unilaterally. Methods of governance must be in place before deployment is attempted, should deployment even be desired. Research in public policy, ethics, and economics, as well as many other disciplines, will be essential to the decision-making process. SRM is only a palliative treatment for climate change, and it is best viewed as part of a portfolio of responses, including mitigation, adaptation, and possibly CDR. At most, SRM is insurance against dangerous consequences that are directly due to increased surface air temperatures.

Efficient generation of volatile cadmium species using Ti(III) and Ti(IV) and application to determination of cadmium by cold vapor generation inductively coupled plasma mass spectrometry (CVG-ICP-MS)†

PubMed Central

Arslan, Zikri; Yilmaz, Vedat; Rose, LaKeysha

2015-01-01

In this study, a highly efficient chemical vapor generation (CVG) approach is reported for determination of cadmium (Cd). Titanium (III) and titanium (IV) were investigated for the first time as catalytic additives along with thiourea, L-cysteine and potassium cyanide (KCN) for generation of volatile Cd species. Both Ti(III) and Ti(IV) provided the highest enhancement with KCN. The improvement with thiourea was marginal (ca. 2-fold), while L-cysteine enhanced signal slightly only with Ti(III) in H2SO4. Optimum CVG conditions were 4% (v/v) HCl + 0.03 M Ti(III) + 0.16 M KCN and 2% (v/v) HNO3 + 0.03 M Ti(IV) + 0.16 M KCN with a 3% (m/v) NaBH4 solution. The sensitivity was improved about 40-fold with Ti(III) and 35-fold with Ti(IV). A limit of detection (LOD) of 3.2 ng L−1 was achieved with Ti(III) by CVG-ICP-MS. The LOD with Ti(IV) was 6.4 ng L−1 which was limited by the blank signals in Ti(IV) solution. Experimental evidence indicated that Ti(III) and Ti(IV) enhanced Cd vapor generation catalytically; for best efficiency mixing prior to reaction with NaBH4 was critical. The method was highly robust against the effects of transition metal ions. No significant suppression was observed in the presence of Co(II), Cr(III), Cu(II), Fe(III), Mn(II), Ni(II) and Zn(II) up to 1.0 μg mL−1. Among the hydride forming elements, no interference was observed from As(III) and Se(IV) at 0.5 μg mL−1 level. The depressive effects from Pb(II) and Sb(III) were not significant at 0.1 μg mL−1 while those from Bi(III) and Sn(II) were marginal. The procedures were validated with determination of Cd by CVG-ICP-MS in a number certified reference materials, including Nearshore seawater (CASS-4), Bone ash (SRM 1400), Dogfish liver (DOLT-4), Mussel tissue (SRM 2976) and Domestic Sludge (SRM 2781). PMID:26251554

Development of a murre (Uria spp.) egg control material

USGS Publications Warehouse

Vander Pol, Stacy S.; Ellisor, M.B.; Pugh, Rebecca S.; Becker, P.R.; Poster, D.L.; Schantz, M.M.; Leigh, S.D.; Wakeford, B.J.; Roseneau, David G.; Simac, K.S.

2007-01-01

The Seabird Tissue Archival and Monitoring Project (STAMP) is a collaborative Alaska-wide effort by the US Fish and Wildlife Service's Alaska Maritime National Wildlife Refuge (USFWS/AMNWR), the US Geological Survey's Biological Resources Division (USGS/BRD), the Bureau of Indian Affairs Alaska Region Subsistence Branch (BIA/ARSB), and the National Institute of Standards and Technology (NIST) to monitor long-term (decadal) trends in environmental contaminants using seabird eggs. To support this effort, a matrix- (seabird egg) and concentration-specific control material was needed to ensure quality during analytical work. Although a herring gull egg quality assurance (HGQA) material is available from Environment Canada (EC), contaminant concentrations in this material tended to be higher than those observed in Alaskan murre (Uria spp.) eggs. Therefore, to prepare a more appropriate control material, a total of 12 common murre (U. aalge) and thick-billed murre (U. lomvia) eggs from four Bering Sea and Gulf of Alaska nesting locations were cryohomogenized to create 190 aliquots each containing approximately 6 g. This new control material was analyzed by different methods at NIST and EC facilities for the determination of concentrations and value assignment of 63 polychlorinated biphenyl (PCB) congeners, 20 organochlorine pesticides, and 11 polybrominated diphenyl ether (PBDE) congeners. The total PCB concentration is approximately 58 ng g -1 wet mass. Results obtained for analytes not listed on the certificates of analysis of the previously used control materials, HGQA and NIST's Standard Reference Material (SRM) 1946 Lake Superior Fish Tissue, are also presented. [Figure not available: see fulltext.]. ?? Springer-Verlag 2007.

Determination of traces of palladium in stream sediment and auto catalyst by FI-ICP-OES using on-line separation and preconcentration with QuadraSil TA.

PubMed

Nakajima, Junichi; Ohno, Masashi; Chikama, Katsumi; Seki, Tatsuya; Oguma, Koichi

2009-09-15

A flow injection analysis (FIA) method using on-line separation and preconcentration with a novel metal scavenger beads, QuadraSil TA, has been developed for the ICP-OES determination of traces of palladium. QuadraSil TA contains diethylenetriamine as a functional group on spherical silica beads and shows the highest selectivity for Pd(II) at pH 1 (0.1 mol l(-1) hydrochloric acid) solution. An aliquot of the sample solution prepared as 0.1 mol l(-1) in hydrochloric acid was passed through the QuadraSil TA column. After washing the column with the carrier solution, the Pd(II) retained on the column was eluted with 0.05 mol l(-1) thiourea solution and the eluate was directly introduced into an ICP-OES. The proposed method was successfully applied to the determination of traces of palladium in JSd-2 stream sediment certified reference material [0.019+/-0.001 microg g(-1) (n=3); provisional value: 0.0212 microg g(-1)] and SRM 2556 used auto catalyst certified reference material [315+/-4 microg g(-1) (n=4); certified value: 326 microg g(-1)]. The detection limit (3 sigma) of 0.28 ng ml(-1) was obtained for 5 ml of sample solution. The sample through puts for 5 ml and 100 microl of the sample solutions were 10 and 15 h(-1), respectively.

Rapid determination of vitamin D₃ in milk-based infant formulas by liquid chromatography-tandem mass spectrometry.

PubMed

Kwak, Byung-Man; Jeong, In-Seek; Lee, Moon-Seok; Ahn, Jang-Hyuk; Park, Jong-Su

2014-12-15

A rapid and simple sample preparation method for vitamin D3 (cholecalciferol) was developed for emulsified dairy products such as milk-based infant formulas. A sample was mixed in a 50 mL centrifuge tube with the same amount of water and isopropyl alcohol to achieve chemical extraction. Ammonium sulfate was used to induce phase separation. No-heating saponification was performed in the sample tube by adding KOH, NaCl, and NH3. Vitamin D3 was then separated and quantified using liquid chromatography-tandem mass spectrometry. The results for added recovery tests were in the range 93.11-110.65%, with relative standard deviations between 2.66% and 2.93%. The results, compared to those obtained using a certified reference material (SRM 1849a), were within the range of the certificated values. This method could be implemented in many laboratories that require time and labour saving. Copyright © 2014 Elsevier Ltd. All rights reserved.

Optimization and Validation of Thermal Desorption Gas Chromatography-Mass Spectrometry for the Determination of Polycyclic Aromatic Hydrocarbons in Ambient Air

PubMed Central

Durana, Nieves; García, José Antonio; Gómez, María Carmen; Alonso, Lucio

2018-01-01

Thermal desorption (TD) coupled with gas chromatography/mass spectrometry (TD-GC/MS) is a simple alternative that overcomes the main drawbacks of the solvent extraction-based method: long extraction times, high sample manipulation, and large amounts of solvent waste. This work describes the optimization of TD-GC/MS for the measurement of airborne polycyclic aromatic hydrocarbons (PAHs) in particulate phase. The performance of the method was tested by Standard Reference Material (SRM) 1649b urban dust and compared with the conventional method (Soxhlet extraction-GC/MS), showing a better recovery (mean of 97%), precision (mean of 12%), and accuracy (±25%) for the determination of 14 EPA PAHs. Furthermore, other 15 nonpriority PAHs were identified and quantified using their relative response factors (RRFs). Finally, the proposed method was successfully applied for the quantification of PAHs in real 8 h-samples (PM10), demonstrating its capability for determination of these compounds in short-term monitoring. PMID:29854561

Dispersive liquid-liquid microextraction of lead(II) as 5-(4-dimethylaminobenzylidene) rhodanine chelates from food and water samples.

PubMed

Alothman, Zeid A; Al-Shaalan, Nora H; Habila, Mohamed A; Unsal, Yunus E; Tuzen, Mustafa; Soylak, Mustafa

2015-02-01

A dispersive liquid-liquid microextraction procedure for lead(II) as its 5-(4-dimethylaminobenzylidene) rhodanine complex has been established prior to its microsampling flame atomic absorption spectrometric determination. The influences of various analytical parameters including pH, solvent type and volume, dispersive solvent type and volume, 5-(4-dimethylaminobenzylidene) rhodanine amount, salt effect, and centrifugation time and speed were investigated. The effects of certain alkali, alkaline earth, and transition metal ions on the quantitative extraction of lead(II) were also studied. Quantitative recoveries were obtained at pH 6. The enrichment factor was calculated as 125. The detection limit for lead is 1.1 μg/L. The accuracy of the method was tested with the additions recovery test and analysis of the standard reference materials (SPS-WW2 waste water, NIST SRM 1515 apple leaves, and TMDA-51.3 fortified water). Applications of the present procedure were tested by analyzing water and food samples.

Polyhydroxybutyrate-b-polyethyleneglycol block copolymer for the solid phase extraction of lead and copper in water, baby foods, tea and coffee samples.

PubMed

Wadhwa, Sham Kumar; Tuzen, Mustafa; Kazi, Tasneem Gul; Soylak, Mustafa; Hazer, Baki

2014-01-01

A new adsorbent, polyhydroxybutyrate-b-polyethyleneglycol, was used for the separation and preconcentration of copper(II) and lead(II) ions prior to their flame atomic absorption spectrometric detections. The influences of parameters such as pH, amount of adsorbent, flow rates and sample volumes were investigated. The polymer does not interact with alkaline, alkaline-earth metals and transition metals. The enrichment factor was 50. The detection limits were 0.32 μg L(-1) and 1.82 μg L(-1) for copper and lead, respectively. The recovery values were found >95%. The relative standard deviations were found to be less than 6%. The validation of the procedure was performed by analysing certified reference materials; NIST SRM 1515 Apple leaves, IAEA-336 Lichen and GBW-07605 Tea. The method was successfully applied for the analysis of analytes in water and food samples. Copyright © 2013 Elsevier Ltd. All rights reserved.

Direct determination of halogens in powdered geological and environmental samples using isotope dilution laser ablation ICP-MS

NASA Astrophysics Data System (ADS)

Boulyga, Sergei F.; Heumann, Klaus G.

2005-04-01

Laser ablation inductively coupled plasma isotope dilution mass spectrometry (LA-ICP-IDMS) with a special laser ablation system for bulk analyses (LINA-Spark(TM)-Atomiser) was applied for direct determinations of chlorine, bromine, and iodine in rock and sediment samples. Special attention was focused on possible inter-halogen fractionations and analyte/spike isotope fractionations by using LA-ICP-MS and LA-ICP-IDMS, respectively. A variation of Br/Cl and I/Cl element intensity ratios by a factor of 1.3-3 was observed when changing the nebulizer gas flow rate in the range of 0.84-1.0 L min-1 and the laser power density in the range of 2-10 GW cm-2, respectively. When using an internal standard for halogen quantification in LA-ICP-MS, this inter-element fractionation can cause systematic errors, which can be avoided by applying the isotope dilution technique. However, at high laser power densities (>5.7 GW cm-2 for iodine and >4.0 GW cm-2 for bromine and chlorine) the corresponding measured isotope ratio of the isotope-diluted sample deviates significantly from the target value. Under optimised conditions concentrations in the range of 30 [mu]g g-1-16 × 103 [mu]g g-1 for chlorine, <2-140 [mu]g g-1 for bromine, and <0.1-31 [mu]g g-1 for iodine were determined by LA-ICP-IDMS in two sediment reference materials (SRM 1646, SRM 2704) and three rock reference samples (GS-N, Granite; BX-N, Bauxite; DT-N, Disthene), which have not been certified for these halogens. The sediment results agree well within the given uncertainties with indicative values by different methods and the results of the rock samples with those obtained by negative thermal ionisation isotope dilution mass spectrometry. The detection limits of LA-ICP-IDMS are 8 [mu]g g-1 for chlorine, 1.7 [mu]g g-1 for bromine, and 0.1 [mu]g g-1 for iodine.

Self-Referenced Memory, Social Cognition, and Symptom Presentation in Autism

ERIC Educational Resources Information Center

Henderson, Heather A.; Zahka, Nicole E.; Kojkowski, Nicole M.; Inge, Anne P.; Schwartz, Caley B.; Hileman, Camilla M.; Coman, Drew C.; Mundy, Peter C.

2009-01-01

Background: We examined performance on a self-referenced memory (SRM) task for higher-functioning children with autism (HFA) and a matched comparison group. SRM performance was examined in relation to symptom severity and social cognitive tests of mentalizing. Method: Sixty-two children (31 HFA, 31 comparison; 8-16 years) completed a SRM task in…

A Progress Report on X-Ray Diffraction Measurements on New Low-Thermal Conductivity Thermoelectric Materials

DTIC Science & Technology

1999-04-01

as the only moving parts and no environmentally unfriendly gases . Thermoelectric generators can also improve fuel efficiency by using the heat lost...Facolta di Chimica Industriale di Bologna, 24[4] (1966) 113-132. 11 — i at £ 73 U « ■ 2-Theta (deg) Figure 1. Calibration plot for SRM1976

Static and dynamic deflection studies of the SRM aft case-nozzle joint

NASA Technical Reports Server (NTRS)

Christian, David C.; Kos, Lawrence D.; Torres, Isaias

1989-01-01

The redesign of the joints on the solid rocket motor (SRM) has prompted the need for analyzing the behavior of the joints using several different types of analyses. The types of analyses performed include modal analysis, static analysis, transient response analysis, and base driving response analysis. The forces used in these analyses to drive the mathematical model include SRM internal chamber pressure, nozzle blowout and side forces, shuttle vehicle lift-off dynamics, SRM pressure transient rise curve, gimbal forces and moments, actuator gimbal loads, and vertical and radial bolt preloads. The math model represented the SRM from the aft base tangent point (1,823.95 in) all the way back to the nozzle, where a simplified, tuned nozzle model was attached. The new design used the radial bolts as an additional feature to reduce the gap opening at the aft dome/nozzle fixed housing interface.

Substantial enhancement in intrinsic coercivity on M-type strontium hexaferrite through the increase in magneto-crystalline anisotropy by co-doping of group-V and alkali elements

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

Ahn, Kyunghan, E-mail: kyunghan.ahn@samsung.com; Ryu, Byungki; Korolev, Dmitry

2013-12-09

The effect of d{sup 1} impurity doping in Sr-hexaferrite (SrM) on the magnetic anisotropy is investigated. First-principles calculations revealed that group-V elements (V, Nb) are stabilized with co-doping of alkali elements. Na{sup 1+}/K{sup 1+} doping at Sr{sup 2+}-site is found to be critical to form the d{sup 1} impurities at Fe-site. Experimentally, Na–V doped SrM shows the intrinsic coercivity of ∼5.4 kOe, which is ∼300% enhancement compared to undoped SrM and comparable value to La–Co co-doped SrM. Finally, the spin-orbit coupling from non-vanishing angular momentum of d{sup 1} impurity in SrM should be a main factor for such a substantialmore » improvement of intrinsic coercivity.« less

Using the snowmelt runoff model to evaluate climate change effects and to compare basin runoff between New Mexico and Idaho.

USDA-ARS?s Scientific Manuscript database

The Snowmelt Runoff Model(SRM) has been developed and tested in small to large basins worldwide. SRM has been found to be very useful for understanding snowmelt processes as well as for simulating or forecasting snowmelt-derived water supplies. SRM is being used in New Mexico in a NSF-funded EPSCo...

Sustained release of a novel anti-quorum-sensing agent against oral fungal biofilms.

PubMed

Feldman, Mark; Shenderovich, Julia; Al-Quntar, Abed Al Aziz; Friedman, Michael; Steinberg, Doron

2015-04-01

Thiazolidinedione-8 (S-8) has recently been identified as a potential anti-quorum-sensing/antibiofilm agent against bacteria and fungi. Based on these results, we investigated the possibility of incorporating S-8 in a sustained-release membrane (SRM) to increase its pharmaceutical potential against Candida albicans biofilm. We demonstrated that SRM containing S-8 inhibits fungal biofilm formation in a time-dependent manner for 72 h, due to prolonged release of S-8. Moreover, the SRM effectively delivered the agent in its active form to locations outside the membrane reservoir. In addition, eradication of mature biofilm by the SRM containing S-8 was also significant. Of note, S-8-containing SRM affected the characteristics of mature C. albicans biofilm, such as thickness, exopolysaccharide (EPS) production, and morphogenesis of fungal cells. The concept of using an antibiofilm agent with no antifungal activity incorporated into a sustained-release delivery system is new in medicine and dentistry. This concept of an SRM containing a quorum-sensing quencher with an antibiofilm effect could pave the way for combating oral fungal infectious diseases. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Analysis of pressure blips in aft-finocyl solid rocket motor

NASA Astrophysics Data System (ADS)

Di Giacinto, M.; Favini, B.; Cavallini, E.

2016-07-01

Ballistic anomalies have frequently occurred during the firing of several solid rocket motors (SRMs) (Inertial Upper Stage, Space Shuttle Redesigned SRM (RSRM) and Titan IV SRM Upgrade (SRMU)), producing even relevant and unexpected variations of the SRM pressure trace from its nominal profile. This paper has the purpose to provide a numerical analysis of the following possible causes of ballistic anomalies in SRMs: an inert object discharge, a slag ejection, and an unexpected increase in the propellant burning rate or in the combustion surface. The SRM configuration under investigation is an aft-finocyl SRM with a first-stage/small booster design. The numerical simulations are performed with a quasi-one-dimensional (Q1D) unsteady model of the SRM internal ballistics, properly tailored to model each possible cause of the ballistic anomalies. The results have shown that a classification based on the head-end pressure (HEP) signature, relating each other the HEP shape and the ballistic anomaly cause, can be made. For each cause of ballistic anomalies, a deepened discussion of the parameters driving the HEP signatures is provided, as well as qualitative and quantitative assessments of the resultant pressure signals.

Accurate Quantification of Cardiovascular Biomarkers in Serum Using Protein Standard Absolute Quantification (PSAQ™) and Selected Reaction Monitoring*

PubMed Central

Huillet, Céline; Adrait, Annie; Lebert, Dorothée; Picard, Guillaume; Trauchessec, Mathieu; Louwagie, Mathilde; Dupuis, Alain; Hittinger, Luc; Ghaleh, Bijan; Le Corvoisier, Philippe; Jaquinod, Michel; Garin, Jérôme; Bruley, Christophe; Brun, Virginie

2012-01-01

Development of new biomarkers needs to be significantly accelerated to improve diagnostic, prognostic, and toxicity monitoring as well as therapeutic follow-up. Biomarker evaluation is the main bottleneck in this development process. Selected Reaction Monitoring (SRM) combined with stable isotope dilution has emerged as a promising option to speed this step, particularly because of its multiplexing capacities. However, analytical variabilities because of upstream sample handling or incomplete trypsin digestion still need to be resolved. In 2007, we developed the PSAQ™ method (Protein Standard Absolute Quantification), which uses full-length isotope-labeled protein standards to quantify target proteins. In the present study we used clinically validated cardiovascular biomarkers (LDH-B, CKMB, myoglobin, and troponin I) to demonstrate that the combination of PSAQ and SRM (PSAQ-SRM) allows highly accurate biomarker quantification in serum samples. A multiplex PSAQ-SRM assay was used to quantify these biomarkers in clinical samples from myocardial infarction patients. Good correlation between PSAQ-SRM and ELISA assay results was found and demonstrated the consistency between these analytical approaches. Thus, PSAQ-SRM has the capacity to improve both accuracy and reproducibility in protein analysis. This will be a major contribution to efficient biomarker development strategies. PMID:22080464

Sulfate-reducing bacteria influence the nucleation and growth of mackinawite and greigite

NASA Astrophysics Data System (ADS)

Picard, Aude; Gartman, Amy; Clarke, David R.; Girguis, Peter R.

2018-01-01

Sedimentary iron sulfide minerals play a key role in maintaining the oxygenation of Earth's atmosphere over geological timescales; they also record critical geochemical information that can be used to reconstruct paleo-environments. On modern Earth, sedimentary iron sulfide mineral formation takes places in low-temperature environments and requires the production of free sulfide by sulfate-reducing microorganisms (SRM) under anoxic conditions. Yet, most of our knowledge on the properties and formation pathways of iron sulfide minerals, including pyrite, derives from experimental studies performed in abiotic conditions, and as such the role of biotic processes in the formation of sedimentary iron sulfide minerals is poorly understood. Here we investigate the role of SRM in the nucleation and growth of iron sulfide minerals in laboratory experiments. We set out to test the hypothesis that SRM can influence Fe-S mineralization in ways other than providing sulfide through the comparison of the physical properties of iron sulfide minerals precipitated in the presence and in the absence of the sulfate-reducing bacterium Desulfovibrio hydrothermalis AM13 under well-controlled conditions. X-ray diffraction and microscopy analyses reveal that iron sulfide minerals produced in the presence of SRM exhibit unique morphology and aggregate differently than abiotic minerals formed in media without cells. Specifically, mackinawite growth is favored in the presence of both live and dead SRM, when compared to the abiotic treatments tested. The cell surface of live and dead SRM, and the extracellular polymers produced by live cells, provide templates for the nucleation of mackinawite and favor mineral growth. The morphology of minerals is however different when live and dead cells are provided. The transformation of greigite from mackinawite occurred after several months of incubation only in the presence of live SRM, suggesting that SRM might accelerate the kinetics of greigite formation under strict anoxic conditions. Pyrite formation was not observed in any experiments. While SRM provide nearly all the sulfide to the Fe-S system at low temperatures, we also posit that SRM play an additional formative role in the size, morphology and potentially the mineralogy of iron sulfide minerals in sedimentary environments, therefore potentially influencing their reactivity. Attempting to reconstruct modern and ancient biogeochemical cycles based on the geochemistry of iron sulfide minerals formed under purely abiotic conditions should be therefore done with caution.

New Carbonate Standard Reference Materials for Boron Isotope Geochemistry

NASA Astrophysics Data System (ADS)

Stewart, J.; Christopher, S. J.; Day, R. D.

2015-12-01

The isotopic composition of boron (δ11B) in marine carbonates is well established as a proxy for past ocean pH. Yet, before palaeoceanographic interpretation can be made, rigorous assessment of analytical uncertainty of δ11B data is required; particularly in light of recent interlaboratory comparison studies that reported significant measurement disagreement between laboratories [1]. Well characterised boron standard reference materials (SRMs) in a carbonate matrix are needed to assess the accuracy and precision of carbonate δ11B measurements throughout the entire procedural chemistry; from sample cleaning, to ionic separation of boron from the carbonate matrix, and final δ11B measurement by multi-collector inductively coupled plasma mass spectrometry. To date only two carbonate reference materials exist that have been value-assigned by the boron isotope measurement community [2]; JCp-1 (porites coral) and JCt-1 (Giant Clam) [3]. The National Institute of Standards and Technology (NIST) will supplement these existing standards with new solution based inorganic carbonate boron SRMs that replicate typical foraminiferal and coral B/Ca ratios and δ11B values. These new SRMs will not only ensure quality control of full procedural chemistry between laboratories, but have the added benefits of being both in abundant supply and free from any restrictions associated with shipment of biogenic samples derived from protected species. Here we present in-house δ11B measurements of these new boron carbonate SRM solutions. These preliminary data will feed into an interlaboratory comparison study to establish certified values for these new NIST SRMs. 1. Foster, G.L., et al., Chemical Geology, 2013. 358(0): p. 1-14. 2. Gutjahr, M., et al., Boron Isotope Intercomparison Project (BIIP): Development of a new carbonate standard for stable isotopic analyses. Geophysical Research Abstracts, EGU General Assembly 2014, 2014. 16(EGU2014-5028-1). 3. Inoue, M., et al., Geostandards and Geoanalytical Research, 2004. 28(3): p. 411-416.

Rhythmic Behavior Is Controlled by the SRm160 Splicing Factor in Drosophila melanogaster.

PubMed

Beckwith, Esteban J; Hernando, Carlos E; Polcowñuk, Sofía; Bertolin, Agustina P; Mancini, Estefania; Ceriani, M Fernanda; Yanovsky, Marcelo J

2017-10-01

Circadian clocks organize the metabolism, physiology, and behavior of organisms throughout the day-night cycle by controlling daily rhythms in gene expression at the transcriptional and post-transcriptional levels. While many transcription factors underlying circadian oscillations are known, the splicing factors that modulate these rhythms remain largely unexplored. A genome-wide assessment of the alterations of gene expression in a null mutant of the alternative splicing regulator SR-related matrix protein of 160 kDa (SRm160) revealed the extent to which alternative splicing impacts on behavior-related genes. We show that SRm160 affects gene expression in pacemaker neurons of the Drosophila brain to ensure proper oscillations of the molecular clock. A reduced level of SRm160 in adult pacemaker neurons impairs circadian rhythms in locomotor behavior, and this phenotype is caused, at least in part, by a marked reduction in period ( per ) levels. Moreover, rhythmic accumulation of the neuropeptide PIGMENT DISPERSING FACTOR in the dorsal projections of these neurons is abolished after SRm160 depletion. The lack of rhythmicity in SRm160-downregulated flies is reversed by a fully spliced per construct, but not by an extra copy of the endogenous locus, showing that SRm160 positively regulates per levels in a splicing-dependent manner. Our findings highlight the significant effect of alternative splicing on the nervous system and particularly on brain function in an in vivo model. Copyright © 2017 by the Genetics Society of America.

Neurogenesis Inhibition Prevents Enriched Environment to Prolong and Strengthen Social Recognition Memory, But Not to Increase BDNF Expression.

PubMed

Pereira-Caixeta, Ana Raquel; Guarnieri, Leonardo O; Pena, Roberta R; Dias, Thomáz L; Pereira, Grace Schenatto

2017-07-01

Hippocampus-dependent memories, such as social recognition (SRM), are modulated by neurogenesis. However, the precise role of newborn neurons in social memory processing is still unknown. We showed previously that 1 week of enriched environment (EE) is sufficient to increase neurogenesis in the hippocampus (HIP) and the olfactory bulb (OB) of mice. Here, we tested the hypothesis that 1 week of EE would enhance SRM persistence and strength. In addition, as brain-derived neurotrophic factor (BDNF) may mediate some of the neurogenesis effects on memory, we also tested if 1 week of EE would increase BDNF expression in the HIP and OB. We also predicted that neurogenesis inhibition would block the gain of function caused by EE on both SRM and BDNF expression. We found that EE increased BDNF expression in the HIP and OB of mice; at the same time, it allowed SRM to last longer. In addition, mice on EE had their SRM unaffected by memory consolidation interferences. As we predicted, treatment with the anti-mitotic drug AraC blocked EE effects on SRM. Surprisingly, neurogenesis inhibition did not affect the BDNF expression, increased by EE. Together, our results suggest that newborn neurons improve SRM persistence through a BDNF-independent mechanism. Interestingly, this study on social memory uncovered an unexpected dissociation between the effect of adult neurogenesis and BDNF expression on memory persistence, reassuring the idea that not all neurogenesis effects on memory are BDNF-dependent.

High Accuracy Thermal Expansion Measurement At Cryogenic Temperatures

NASA Technical Reports Server (NTRS)

Stallcup, Michael; Presson, Joan; Tucker, James; Daspit, Gregory; Nein, Max

2003-01-01

A new, interferometer based system for measuring thermal expansion to an absolute accuracy of 20 ppb or better at cryogenic temperatures has been developed. Data from NIST Copper SRM 736 measured from room temperature to 15 K will be presented along with data from many other materials including beryllium, ULE, Zerodur, and composite materials. Particular attention will be given to a study by the Space Optics Manufacturing Technology Center (SOMTC) investigating the variability of ULE and beryllium materials used in the AMSD program. Approximately 20 samples of each material, tested from room temperature to below 30 K are compared as a function of billet location.

High Accuracy Thermal Expansion Measurement at Cryogenic Temperatures

NASA Technical Reports Server (NTRS)

Tucker, Jim; Despit, Gregory; Stallcup, Michael; Presson, Joan; Nein, Max

2003-01-01

A new, interferometer-based system for measuring thermal expansion to an absolute accuracy of 20 ppb or better at cryogenic temperatures has been developed. Data from NIST Copper SRM 736 measured from room temperature to 15 K will be presented along with data from many other materials including beryllium, ULE, Zerodur, and composite materials. Particular attention will be given to a study by the Space Optics Manufacturing Technology Center (SOMTC) investigating the variability of ULE and beryllium materials used in the AMSD program Approximately 20 samples of each material, tested from room temperature to below 30 K are compared as a function of billet location.

Screening of the chemical reactivity of three different graphite sources using the formation of reductively alkylated graphene as a model reaction.

PubMed

Knirsch, Kathrin C; Englert, Jan M; Dotzer, Christoph; Hauke, Frank; Hirsch, Andreas

2013-11-28

Reductive alkylation of three graphite starting materials G(flake), G(powder), and G(spherical) reveals pronounced differences in the obtained covalently functionalized graphene with respect to the degree of functionalization, exfoliation efficiency and product homogeneity, as demonstrated by statistical Raman microscopy (SRM), TGA/MS, IR-spectroscopy and solubility behavior.

Influence of different propellant systems on ablation of EPDM insulators in overload state

NASA Astrophysics Data System (ADS)

Guan, Yiwen; Li, Jiang; Liu, Yang; Xu, Tuanwei

2018-04-01

This study examines the propellants used in full-scale solid rocket motors (SRM) and investigates how insulator ablation is affected by two propellant formulations (A and B) during flight overload conditions. An experimental study, theoretical analysis, and numerical simulations were performed to discover the intrinsic causes of insulator ablation rates from the perspective of lab-scaled ground-firing tests, the decoupling of thermochemical ablation, and particle erosion. In addition, the difference in propellant composition, and the insulator charring layer microstructure were analyzed. Results reveal that the degree of insulator ablation is positively correlated with the propellant burn rate, particle velocity, and aggregate concentrations during the condensed phase. A lower ratio of energetic additive material in the AP oxidizer of the propellant is promising for the reduction in particle size and increase in the burn rate and pressure index. However, the overall higher velocity of a two-phase flow causes severe erosion of the insulation material. While the higher ratio of energetic additive to the AP oxidizer imparts a smaller ablation rate to the insulator (under lab-scale test conditions), the slag deposition problem in the combustion chamber may cause catastrophic consequences for future large full-scale SRM flight experiments.

Application of supercritical fluid chromatography coupled to mass spectrometry to the determination of fat-soluble vitamins in selected food products.

PubMed

Oberson, Jean-Marie; Campos-Giménez, Esther; Rivière, Johann; Martin, Frédéric

2018-06-01

In the present manuscript, we describe a fully optimized and validated method suitable to analyse nine compounds (retinyl acetate, retinyl palmitate, retinol, α-tocopherol, α-tocopheryl acetate, cholecalciferol, ergocalciferol, phylloquinone, menaquinone-4) representing the major contributors to the fat-soluble vitamin activity of selected food products (infant formulas, adult nutritionals, infant cereals and mixed meals). Sample preparation involves direct solvent extraction using enzyme-assisted matrix disintegration and methanolic protein precipitation. Direct injection of the extract allows quantification of vitamins A, E and K in only 7 min, while vitamin D is determined after fast derivatization of the extract. Separation is achieved by supercritical fluid chromatography and detection performed by tandem mass spectrometry in positive Atmospheric Pressure Chemical Ionization mode. Results on a Standard Reference Material (SRM 1849a Infant/Adult Nutritional) were not statistically different from reference values. Full validation of the method showed excellent overall performance. Average recovery rate was between 90 and 110% for all vitamins and matrixes. The methodology shows enhanced safety and reduced cost as compared with previously published methods, together with potential for application to more complex matrixes. The full procedure can be easily applied in control laboratories dramatically increasing sample throughput and reducing solvent consumption. Copyright © 2018 Elsevier B.V. All rights reserved.

Scenario of solid waste reuse in Khulna city of Bangladesh

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

Bari, Quazi H., E-mail: qhbari@yahoo.com; Mahbub Hassan, K.; Haque, R.

2012-12-15

The reuse and recycling of waste materials are now sincerely considered to be an integral part of solid waste management in many parts of the world. In this context, a vast number of options ranging from small scale decentralized to larger scale centralized plants have been adopted. This study aimed at investigating the waste reuse schemes in Khulna city located in the southern part of Bangladesh and ranked third largest city in the country. The shops for reusable material (SRM) were mostly situated around railway, waterway, and truck station markets which provided easy transportation to further locations. For the reusesmore » of waste materials and products, a chain system was found to collect reusable wastes under a total number of 310 identified SRM with 859 persons directly or indirectly involved in the scheme. This was a decentralized waste management system with self sufficient (autonomous) management. According to mass balance, about 38.52 tons d{sup -1} solid wastes were reused in Khulna city area, accounting for 7.65% of the total generated wastes. This study revealed that apparently a silent, systematic, smooth, and clean reuse chain has been established in Khulna city area under private initiatives, whose sustainability was confirmed over the years in the country without any official or formal funds. However, proper adjustment between the higher and lower chain in the materials flow path, as well as personal hygiene training for the workers, would further improve the achievements of the established reuse scheme.« less

Scenario of solid waste reuse in Khulna city of Bangladesh.

PubMed

Bari, Quazi H; Mahbub Hassan, K; Haque, R

2012-12-01

The reuse and recycling of waste materials are now sincerely considered to be an integral part of solid waste management in many parts of the world. In this context, a vast number of options ranging from small scale decentralized to larger scale centralized plants have been adopted. This study aimed at investigating the waste reuse schemes in Khulna city located in the southern part of Bangladesh and ranked third largest city in the country. The shops for reusable material (SRM) were mostly situated around railway, waterway, and truck station markets which provided easy transportation to further locations. For the reuses of waste materials and products, a chain system was found to collect reusable wastes under a total number of 310 identified SRM with 859 persons directly or indirectly involved in the scheme. This was a decentralized waste management system with self sufficient (autonomous) management. According to mass balance, about 38.52 tons d(-1) solid wastes were reused in Khulna city area, accounting for 7.65% of the total generated wastes. This study revealed that apparently a silent, systematic, smooth, and clean reuse chain has been established in Khulna city area under private initiatives, whose sustainability was confirmed over the years in the country without any official or formal funds. However, proper adjustment between the higher and lower chain in the materials flow path, as well as personal hygiene training for the workers, would further improve the achievements of the established reuse scheme. Copyright © 2012 Elsevier Ltd. All rights reserved.

Absolute Calibration of Si iRMs used for Measurements of Si Paleo-nutrient proxies

NASA Astrophysics Data System (ADS)

Vocke, R. D., Jr.; Rabb, S. A.

2016-12-01

Silicon isotope variations (reported as δ30Si and δ29Si, relative to NBS28) in silicic acid dissolved in ocean waters, in biogenic silica and in diatoms are extremely informative paleo-nutrient proxies. The resolution and comparability of such measurements depend on the quality of the isotopic Reference Materials (iRMs) defining the delta scale. We report new absolute Si isotopic measurements on the iRMs NBS28 (RM 8546 - Silica Sand), Diatomite, and Big Batch using the Avogadro measurement approach and comparing them with prior assessments of these iRMs. The Avogadro Si measurement technique was developed by the German Physikalish-Technische Bundesanstalt (PTB) to provide a precise and highly accurate method to measure absolute isotopic ratios in highly enriched 28Si (99.996%) material. These measurements are part of an international effort to redefine the kg and mole based on the Planck constant h and the Avogadro constant NA, respectively (Vocke et al., 2014 Metrologia 51, 361, Azuma et al., 2015 Metrologia 52 360). This approach produces absolute Si isotope ratio data with lower levels of uncertainty when compared to the traditional "Atomic Weights" method of absolute isotope ratio measurement calibration. This is illustrated in Fig. 1 where absolute Si isotopic measurements on SRM 990, separated by 40+ years of advances in instrumentation, are compared. The availability of this new technique does not say that absolute Si isotopic ratios are or ever will be better for normal Si isotopic measurements when seeking isotopic variations in nature, because they are not. However, by determining the absolute isotopic ratios of all the Si iRM scale artifacts, such iRMs become traceable to the metric system (SI); thereby automatically conferring on all the artifact-based δ30Si and δ29Si measurements traceability to the base SI unit, the mole. Such traceability should help reduce the potential of bias between different iRMs and facilitate the replacement of delta-scale artefacts when they run out. Fig. 1 Comparison of absolute isotopic measurements of SRM 990 using two radically different approaches to absolute calibration and mass bias corrections.

Protein turnover measurement using selected reaction monitoring-mass spectrometry (SRM-MS)

PubMed Central

Holman, Stephen W.; Hammond, Dean E.; Simpson, Deborah M.; Waters, John; Hurst, Jane L.

2016-01-01

Protein turnover represents an important mechanism in the functioning of cells, with deregulated synthesis and degradation of proteins implicated in many diseased states. Therefore, proteomics strategies to measure turnover rates with high confidence are of vital importance to understanding many biological processes. In this study, the more widely used approach of non-targeted precursor ion signal intensity (MS1) quantification is compared with selected reaction monitoring (SRM), a data acquisition strategy that records data for specific peptides, to determine if improved quantitative data would be obtained using a targeted quantification approach. Using mouse liver as a model system, turnover measurement of four tricarboxylic acid cycle proteins was performed using both MS1 and SRM quantification strategies. SRM outperformed MS1 in terms of sensitivity and selectivity of measurement, allowing more confident determination of protein turnover rates. SRM data are acquired using cheaper and more widely available tandem quadrupole mass spectrometers, making the approach accessible to a larger number of researchers than MS1 quantification, which is best performed on high mass resolution instruments. SRM acquisition is ideally suited to focused studies where the turnover of tens of proteins is measured, making it applicable in determining the dynamics of proteins complexes and complete metabolic pathways. This article is part of the themed issue ‘Quantitative mass spectrometry’. PMID:27644981

Analysis of Serum Total and Free PSA Using Immunoaffinity Depletion Coupled to SRM: Correlation with Clinical Immunoassay Tests

PubMed Central

Liu, Tao; Hossain, Mahmud; Schepmoes, Athena A.; Fillmore, Thomas L.; Sokoll, Lori J.; Kronewitter, Scott R.; Izmirlian, Grant; Shi, Tujin; Qian, Wei-Jun; Leach, Robin J.; Thompson, Ian M.; Chan, Daniel W.; Smith, Richard D.; Kagan, Jacob; Srivastava, Sudhir; Rodland, Karin D.; Camp, David G.

2012-01-01

Recently, selected reaction monitoring mass spectrometry (SRM-MS) has been more frequently applied to measure low abundance biomarker candidates in tissues and biofluids, owing to its high sensitivity and specificity, simplicity of assay configuration, and exceptional multiplexing capability. In this study, we report for the first time the development of immunoaffinity depletion-based workflows and SRM-MS assays that enable sensitive and accurate quantification of total and free prostate-specific antigen (PSA) in serum without the requirement for specific PSA antibodies. Low ng/mL level detection of both total and free PSA was consistently achieved in both PSA-spiked female serum samples and actual patient serum samples. Moreover, comparison of the results obtained when SRM PSA assays and conventional immunoassays were applied to the same samples showed good correlation in several independent clinical serum sample sets. These results demonstrate that the workflows and SRM assays developed here provide an attractive alternative for reliably measuring candidate biomarkers in human blood, without the need to develop affinity reagents. Furthermore, the simultaneous measurement of multiple biomarkers, including the free and bound forms of PSA, can be performed in a single multiplexed analysis using high-resolution liquid chromatographic separation coupled with SRM-MS. PMID:22846433

Accuracy of the Velotron ergometer and SRM power meter.

PubMed

Abbiss, C R; Quod, M J; Levin, G; Martin, D T; Laursen, P B

2009-02-01

The purpose of this study was to determine the accuracy of the Velotron cycle ergometer and the SRM power meter using a dynamic calibration rig over a range of exercise protocols commonly applied in laboratory settings. These trials included two sustained constant power trials (250 W and 414 W), two incremental power trials and three high-intensity interval power trials. To further compare the two systems, 15 subjects performed three dynamic 30 km performance time trials. The Velotron and SRM displayed accurate measurements of power during both constant power trials (<1% error). However, during high-intensity interval trials the Velotron and SRM were found to be less accurate (3.0%, CI=1.6-4.5% and -2.6%, CI=-3.2--2.0% error, respectively). During the dynamic 30 km time trials, power measured by the Velotron was 3.7+/-1.9% (CI=2.9-4.8%) greater than that measured by the SRM. In conclusion, the accuracy of the Velotron cycle ergometer and the SRM power meter appears to be dependent on the type of test being performed. Furthermore, as each power monitoring system measures power at various positions (i.e. bottom bracket vs. rear wheel), caution should be taken when comparing power across the two systems, particularly when power is variable.

Spatial release from masking based on binaural processing for up to six maskers

PubMed Central

Yost, William A.

2017-01-01

Spatial Release from Masking (SRM) was measured for identification of a female target word spoken in the presence of male masker words. Target words from a single loudspeaker located at midline were presented when two, four, or six masker words were presented either from the same source as the target or from spatially separated masker sources. All masker words were presented from loudspeakers located symmetrically around the centered target source in the front azimuth hemifield. Three masking conditions were employed: speech-in-speech masking (involving both informational and energetic masking), speech-in-noise masking (involving energetic masking), and filtered speech-in-filtered speech masking (involving informational masking). Psychophysical results were summarized as three-point psychometric functions relating proportion of correct word identification to target-to-masker ratio (in decibels) for both the co-located and spatially separated target and masker sources cases. SRM was then calculated by comparing the slopes and intercepts of these functions. SRM decreased as the number of symmetrically placed masker sources increased from two to six. This decrease was independent of the type of masking, with almost no SRM measured for six masker sources. These results suggest that when SRM is dependent primarily on binaural processing, SRM is effectively limited to fewer than six sound sources. PMID:28372135

Estimating option values of solar radiation management assuming that climate sensitivity is uncertain.

PubMed

Arino, Yosuke; Akimoto, Keigo; Sano, Fuminori; Homma, Takashi; Oda, Junichiro; Tomoda, Toshimasa

2016-05-24

Although solar radiation management (SRM) might play a role as an emergency geoengineering measure, its potential risks remain uncertain, and hence there are ethical and governance issues in the face of SRM's actual deployment. By using an integrated assessment model, we first present one possible methodology for evaluating the value arising from retaining an SRM option given the uncertainty of climate sensitivity, and also examine sensitivities of the option value to SRM's side effects (damages). Reflecting the governance challenges on immediate SRM deployment, we assume scenarios in which SRM could only be deployed with a limited degree of cooling (0.5 °C) only after 2050, when climate sensitivity uncertainty is assumed to be resolved and only when the sensitivity is found to be high (T2x = 4 °C). We conduct a cost-effectiveness analysis with constraining temperature rise as the objective. The SRM option value is originated from its rapid cooling capability that would alleviate the mitigation requirement under climate sensitivity uncertainty and thereby reduce mitigation costs. According to our estimates, the option value during 1990-2049 for a +2.4 °C target (the lowest temperature target level for which there were feasible solutions in this model study) relative to preindustrial levels were in the range between $2.5 and $5.9 trillion, taking into account the maximum level of side effects shown in the existing literature. The result indicates that lower limits of the option values for temperature targets below +2.4 °C would be greater than $2.5 trillion.

Identification and quantification of cardiac glycosides in blood and urine samples by HPLC/MS/MS.

PubMed

Guan, F; Ishii, A; Seno, H; Watanabe-Suzuki, K; Kumazawa, T; Suzuki, O

1999-09-15

Cardiac glycosides (CG) are of forensic importance because of their toxicity and the fact that very limited methods are available for identification of CG in biological samples. In this study, we have developed an identification and quantification method for digoxin, digitoxin, deslanoside, digoxigenin, and digitoxigenin by high-performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS). CG formed abundant [M + NH4]+ ions and much less abundant [M + H]+ ions as observed with electrospray ionization (ESI) source and ammonium formate buffer. Under mild conditions for collision-induced dissociation (CID), each [M + NH4]+ ion fragmented to produce a dominant daughter ion, which was essential to the sensitive method of selected reaction monitoring (SRM) quantification of CG achieved in this study. SRM was compared with selected ion monitoring (SIM) regarding the effects of sample matrixes on the methodology. SRM produced lower detection limits with biological samples than SIM, while both methods produced equal detection limits with CG standards. On the basis of the HPLC/MS/MS results for CG, we have proposed some generalized points for conducting sensitive SRM measurements, in view of the property of analytes as well as instrumental conditions such as the type of HPLC/MS interface and CID parameters. Analytes of which the molecular ion can produce one abundant daughter ion with high yield under CID conditions may be sensitively measured by SRM. ESI is the most soft ionization source developed so far and can afford formation of the fragile molecular ions that are necessary for sensitive SRM detection. Mild CID conditions such as low collision energy and low pressure of collision gas favor production of an abundant daughter ion that is essential to sensitive SRM detection. This knowledge may provide some guidelines for conducting sensitive SRM measurements of very low concentrations of drugs or toxicants in biological samples.

An evaluation of the interfacial bond properties between carbon phenolic and glass phenolic composites

NASA Technical Reports Server (NTRS)

Jordan, Kelvin; Clinton, Raymond; Jeelani, Shaik

1989-01-01

The effects of moisture and surface finish on the mechanical and physical properties of the interfacial bond between the carbon/phenolic (C/P) and glass/phenolic (G/P) composite materials are presented. Four flat panel laminates were fabricated using the C/P and G/P materials. Of the four laminates, one panel was fabricated in which the C/P and G/P materials were cured simultaneously. It was identified as the cocure. The remaining laminates were processed with an initial simultaneous cure of the three C/P billets. Two surface finishes, one on each half, were applied to the top surface. Prior to the application and cure of the G/P material to the machined surface of the three C/P panels, each was subjected to the specific environmental conditioning. Types of conditioning included: (1) nominal fabrication environment, (2) a prescribed drying cycle, and (3) a total immersion in water at 160 F. Physical property tests were performed on specimens removed from the C/P materials of each laminate for determination of the specific gravity, residual volatiles and and resin content. Comparisons of results with shuttle solid rocket motor (SRM) nozzle material specifications verified that the materials used in fabricating the laminates met acceptance criteria and were representative of SRM nozzle materials. Mechanical property tests were performed at room temperature on specimens removed from the G/P, the C/P and the interface between the two materials for each laminate. The double-notched shear strength test was used to determine the ultimate interlaminar shear strength. Results indicate no appreciable difference in the C/P material of the four laminates with the exception of the cocure laminate, where 20 percent reduction in the strength was observed. The most significant effect and the ultimate strength was significantly reduced in the wet material. No appreciable variation was noted between the surface finishes in the wet laminate.

The UK geochemical environment and cardiovascular diseases: magnesium in food and water.

PubMed

Davies, B E

2015-06-01

Cardiovascular diseases (CVDs) contribute approximately one-third to noncommunicable diseases in the UK. The central role of magnesium in CVDs (enzyme activity, cardiac signalling, etc.) is well established. Mortality and morbidity rates for CVDs may be inversely related to water hardness, suggesting a role for environmental magnesium. Published official and quasi-official data sources were evaluated to establish a model magnesium intake for a representative adult: standardised reference individual (SRI), standardised reference male (SRM) or standardised reference female (SRF). For typical dietary constituents, only tap water is probably locally derived and bottled water may not be. Fruits and vegetables are imported from many countries, while meat, dairy and cereal products represent a composite of UK source areas. Alcoholic beverages provide magnesium, there is doubt about its absorptive efficiency, and they are not locally derived. A simple model was devised to examine the effect of varying dietary contributions to total daily intake of magnesium. Omitting tap or bottled water, the combined intake, solid food plus alcoholic beverages, is 10.57 mmol Mg (84.5 % RNI) for the SRM and for the SRF, 8.10 mmol Mg (71.7 % RNI). Consumers drinking water derived from reservoirs or rivers, or supplementing it with the purest bottled water, improve their magnesium intake only slightly compared with water containing no magnesium. Choosing bottled water with high magnesium content when the public supply derives from rivers or reservoirs partially satisfies magnesium needs. Real improvement in SRI magnesium nutrition is seen only where water is hard. However, this conclusion cannot be validated until new measurement technologies for body magnesium become available.

Design of a space shuttle structural dynamics model

NASA Technical Reports Server (NTRS)

1972-01-01

A 1/8 scale structural dynamics model of a parallel burn space shuttle has been designed. Basic objectives were to represent the significant low frequency structural dynamic characteristics while keeping the fabrication costs low. The model was derived from the proposed Grumman Design 619 space shuttle. The design includes an orbiter, two solid rocket motors (SRM) and an external tank (ET). The ET consists of a monocoque LO2 tank an interbank skirt with three frames to accept SRM attachment members, an LH2 tank with 10 frames of which 3 provide for orbiter attachment members, and an aft skirt with on frame to provide for aft SRM attachment members. The frames designed for the SRM attachments are fitted with transverse struts to take symmetric loads.

Block 2 SRM conceptual design studies. Volume 1, Book 1: Conceptual design package

NASA Technical Reports Server (NTRS)

Smith, Brad; Williams, Neal; Miller, John; Ralston, Joe; Richardson, Jennifer; Moore, Walt; Doll, Dan; Maughan, Jeff; Hayes, Fred

1986-01-01

The conceptual design studies of a Block 2 Solid Rocket Motor (SRM) require the elimination of asbestos-filled insulation and was open to alternate designs, such as case changes, different propellants, modified burn rate - to improve reliability and performance. Limitations were placed on SRM changes such that the outside geometry should not impact the physical interfaces with other Space Shuttle elements and should have minimum changes to the aerodynamic and dynamic characteristics of the Space Shuttle vehicle. Previous Space Shuttle SRM experience was assessed and new design concepts combined to define a valid approach to assured flight success and economic operation of the STS. Trade studies, preliminary designs, analyses, plans, and cost estimates are documented.

Technology transfer into the solid propulsion industry

NASA Technical Reports Server (NTRS)

Campbell, Ralph L.; Thomson, Lawrence J.

1995-01-01

This paper is a survey of the waste minimization efforts of industries outside of aerospace for possible applications in the manufacture of solid rocket motors (SRM) for NASA. The Redesigned Solid Rocket Motor (RSRM) manufacturing plan was used as the model for processes involved in the production of an SRM. A literature search was conducted to determine the recycling, waste minimization, and waste treatment methods used in the commercial sector that might find application in SRM production. Manufacturers, trade organizations, and professional associations were also contacted. Waste minimization efforts for current processes and replacement technologies, which might reduce the amount or severity of the wastes generated in SRM production, were investigated. An overview of the results of this effort are presented in this paper.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory : determination of polycyclic aromatic hydrocarbon compounds in sediment by gas chromatography/mass spectrometry

USGS Publications Warehouse

Olson, Mary C.; Iverson, Jana L.; Furlong, Edward T.; Schroeder, Michael P.

2004-01-01

A method for the determination of 28 polycyclic aromatic hydrocarbons (PAHs) and 25 alkylated PAH homolog groups in sediment samples is described. The compounds are extracted from sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography. The compounds are identified and uantitated using capillary-column gas chromatography/mass spectrometry. The report presents performance data for full-scan ion monitoring. Method detection limits in laboratory reagent matrix samples range from 1.3 to 5.1 micrograms per kilogram for the 28 PAHs. The 25 groups of alkylated PAHs are homologs of five groups of isomeric parent PAHs. Because of the lack of authentic standards, these homologs are reported semiquantitatively using a response factor from a parent PAH or a specific alkylated PAH. Precision data for the alkylated PAH homologs are presented using two different standard reference manuals produced by the National Institute of Standards and Technology: SRM 1941b and SRM 1944. The percent relative standard deviations for identified alkylated PAH homolog groups ranged from 1.55 to 6.98 for SRM 1941b and from 6.11 to 12.0 for SRM 1944. Homolog group concentrations reported under this method include the concentrations of individually identified compounds that are members of the group. Organochlorine (OC) pesticides--including toxaphene, polychlorinated biphenyls (PCBs), and organophosphate (OP) pesticides--can be isolated simultaneously using this method. In brief, sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethan (95 percent) and methanol (5 percent). The extract is concentrated and then filtered through a 0.2-micrometer polytetrafluoroethylene syringe filter. The PAH fraction is isolated by quantitatively injecting an aliquot of sample onto two polystyrene-divinylbenzene gel-permeation chromatographic columns connected in series. The compounds are eluted with dichloromethane, a PAH fraction is collected, and a portion of the coextracted interferences, including elemental sulfur, is separated and discarded. The extract is solvent exchanged, the volume is reduced, and internal standard is added. Sample analysis is completed using a gas chromatograph/mass spectrometer and full-scan acquisition.

Characterization and Detailed Analysis of Regression Behavior for HTPB Solid Fuels Containing High Aluminum Loadings

NASA Technical Reports Server (NTRS)

Kibbey, Timothy P.; Cortopassi, Andrew C.; Boyer, Eric C.

2017-01-01

NASA Marshall Space Flight Center's Materials and Processes Department, with support from the Propulsion Systems Department, has renewed the development and maintenance of a hybrid test bed for exposing ablative thermal protection materials to an environment similar to that seen in solid rocket motors (SRM). The Solid Fuel Torch (SFT), operated during the Space Shuttle program, utilized gaseous oxygen for oxidizer and an aluminized hydroxyl-terminated polybutadiene (HTPB) fuel grain to expose a converging section of phenolic material to a 400 psi, 2-phase flow combustion environment. The configuration allows for up to a 2 foot long, 5 inch diameter fuel grain cartridge. Wanting to now test rubber insulation materials with a turn-back feature to mimic the geometry of an aft dome being impinged by alumina particles, the throat area has now been increased by several times to afford flow similarity. Combined with the desire to maintain a higher operating pressure, the oxidizer flow rate is being increased by a factor of 10. Out of these changes has arisen the need to characterize the fuel/oxidizer combination in a higher mass flux condition than has been previously tested at MSFC, and at which the literature has little to no reporting as well. For (especially) metalized fuels, hybrid references have pointed out possible dependence of fuel regression rate on a number of variables: mass flux, G - oxidizer only (G0), or - total mass flux (Gtot), Length, L, Pressure, P, and Diameter, D.

An Assessment of 25-Hydroxyvitamin D Measurements in Comparability Studies Conducted by the Vitamin D Metabolites Quality Assurance Program

PubMed Central

Bedner, Mary; Lippa, Katrice A.; Tai, Susan S.-C.

2013-01-01

Background The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health Office of Dietary Supplements, established the first accuracy-based program for improving the comparability of vitamin D metabolite measurements, the Vitamin D Metabolites Quality Assurance Program. Methods Study samples were comprised of human serum or plasma Standard Reference Materials (SRMs) with 25-hydroxyvitamin D values that were determined at NIST. Participants evaluated the materials using immunoassay (IA), liquid chromatography (LC) with mass spectrometric detection, and LC with ultraviolet absorbance detection. NIST evaluated the results for concordance within the participant community as well as trueness relative to the NIST value. Results For the study materials that contain mostly 25-hydroxyvitamin D3 (25(OH)D3), the coefficient of variation (CV) for the participant results was consistently in the range from 7% to 19%, and the median values were biased high relative to the NIST values. However, for materials that contain significant concentrations of both 25-hydroxyvitamin D2 (25(OH)D2) and 25(OH)D3, the median IA results were biased lower than both the LC and the NIST values, and the CV was as high as 28%. The first interlaboratory comparison results for SRM 972a Vitamin D Metabolites in Human Serum are also reported. Conclusions Relatively large within-lab and between-lab variability hinders conclusive assessments of bias and accuracy. PMID:23978484

Loglines. May - June 2011

DTIC Science & Technology

2011-06-01

chief of the Aerial Delivery and Textile Section. When orders for construction material peaked in 2010, the riggers helped pack about 200 air...ensures effective inspection programs and that SRM projects are scheduled to ensure critical defense missions can be fueled while the projects are...the Active Item Walk and Pick helps distribution workers quickly grab any of 8,000 items considered fast movers, such as washers and gaskets

Liquid Chromatography with Post-Column Reagent Addition of Ammonia in Methanol Coupled to Negative Ion Electrospray Ionization Tandem Mass Spectrometry for Determination of Phenoxyacid Herbicides and their Degradation Products in Surface Water

PubMed Central

Raina, Renata; Etter, Michele L.

2010-01-01

A new liquid chromatography (LC)-negative ion electrospray ionization (ESI−)–tandem mass spectrometry (MS/MS) method with post-column addition of ammonia in methanol has been developed for the analysis of acid herbicides: 2,4-dichlorophenoxy acetic acid, 4-chloro-o-tolyloxyacetic acid, 2-(2-methyl-4-chlorophenoxy)butyric acid, mecoprop, dichlorprop, 4-(2,4-dichlorophenoxy) butyric acid, 2,4,5-trichlorophenoxy propionic acid, dicamba and bromoxynil, along with their degradation products: 4-chloro-2-methylphenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol and 3,5-dibromo-4-hydroxybenzoic acid. The samples were extracted from the surface water matrix using solid-phase extraction (SPE) with a polymeric sorbent and analyzed with LC ESI− with selected reaction monitoring (SRM) using a three-point confirmation approach. Chromatography was performed on a Zorbax Eclipse XDB-C18 (50 × 4.6 mm i.d., 1.8 μm) with a gradient elution using water-methanol with 2 mM ammonium acetate mobile phase at a flow rate of 0.15 mL/min. Ammonia in methanol (0.8 M) was added post-column at a flow rate of 0.05 mL/min to enhance ionization of the degradation products in the MS source. One SRM transition was used for quantitative analysis while the second SRM along with the ratio of SRM1/SRM2 within the relative standard deviation determined by standards for each individual pesticide and retention time match were used for confirmation. The standard deviation of ratio of SRM1/SRM2 obtained from standards run on the day of analysis for different phenoxyacid herbicides ranged from 3.9 to 18.5%. Limits of detection (LOD) were between 1 and 15 ng L−1 and method detection limits (MDL) with strict criteria requiring <25% deviation of peak area from best-fit line for both SRM1 and SRM2 ranged from 5 to 10 ng L−1 for acid ingredients (except dicamba at 30 ng L−1) and from 2 to 30 ng L−1 for degradation products. The SPE-LC-ESI− MS/MS method permitted low nanogram-per-liter determination of pesticides and degradation products for surface water samples. PMID:20212919

Prosopis cineraria: a potential nootropic agent.

PubMed

Bithu, Bhawani Singh; Reddy, N Ranga; Prasad, Satyendra K; Sairam, Krishnamurthy; Hemalatha, S

2012-10-01

Prosopis cineraria (L.) Druce (Leguminosae), a plant of the Thar Desert of India and Pakistan is used traditionally by local people for the treatment of memory disorders and to arrest wandering of the mind. The study includes scientific validation of P. cineraria for nootropic activity. To elucidate the possible mechanism, the anticholinesterase activity was also investigated in different parts of the brain. Methanol extract of P. cineraria stem bark (200, 400 and 600 mg/kg body weight p.o.) was administered once in a day for 7 days to rats and these rats were then subjected to Morris water-maze (MWM) test for spatial reference memory (SRM) and spatial working memory (SWM) versions of memory testing. The inhibitory effect of the extract on acetylcholinesterase (AChE) in discrete rat brain regions (prefrontal cortex [PFC], hippocampus [HIP] and amygdala [AMY]) was also investigated using acetyl thiocholine iodide and dithiobisnitrobenzoic acid reagent. The oral administrations of methanol extract of P. cineraria in all doses tested, significantly (p < 0.05) improved both spatial reference and working memories in the MWM test in terms of decrease in escape latency during SRM and increase in time spent in the target quadrant during SWM probe trial. A ceiling effect was observed at 400 mg/kg. Pre-treatment for 7 days significantly inhibited the activity of AChE in the HIP, PFC and AMY. The extract exerted significant nootropic activity in the MWM test which may be attributed to the inhibition of brain AChE.

Determination of high-molecular weight polycyclic aromatic hydrocarbons in high performance liquid chromatography fractions of coal tar standard reference material 1597a via solid-phase nanoextraction and laser-excited time-resolved Shpol'skii spectroscopy

PubMed Central

Wilson, Walter B.; Alfarhani, Bassam; Moore, Anthony F. T.; Bisson, Cristina; Wise, Stephen A.; Campiglia, Andres D.

2016-01-01

This article presents an alternative approach for the analysis of high molecular weight – polycyclic aromatic hydrocarbons (HMW-PAHs) with molecular mass 302 Da in complex environmental samples. This is not a trivial task due to the large number of molecular mass 302 Da isomers with very similar chromatographic elution times and similar, possibly even virtually identical, mass fragmentation patterns. The method presented here is based on 4.2 K laser-excited time-resolved Shpol'skii spectroscopy, a high resolution spectroscopic technique with the appropriate selectivity for the unambiguous determination of PAHs with the same molecular mass. The potential of this approach is demonstrated here with the analysis of a coal tar standard reference material (SRM) 1597a. Liquid chromatography fractions were submitted to the spectroscopic analysis of five targeted isomers, namely dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene, naphtho[2,3-a]pyrene and dibenzo[a,h]pyrene. Prior to analyte determination, the liquid chromatographic fractions were pre-concentrated with gold nanoparticles. Complete analysis was possible with microliters of chromatographic fractions and organic solvents. The limits of detection varied from 0.05 (dibenzo[a,l]pyrene) to 0.24 μg L−1 (dibenzo[a,e]pyrene). The excellent analytical figures of merit associated to its non-destructive nature, which provides ample opportunity for further analysis with other instrumental methods, makes this approach an attractive alternative for the determination of PAH isomers in complex environmental samples. PMID:26653471

Comparison of solid phase extraction, saponification and gel permeation chromatography for the clean-up of microwave-assisted biological extracts in the analysis of polycyclic aromatic hydrocarbons.

PubMed

Navarro, P; Cortazar, E; Bartolomé, L; Deusto, M; Raposo, J C; Zuloaga, O; Arana, G; Etxebarria, N

2006-09-22

The feasibility of different clean-up procedures was studied for the determination of polycyclic aromatic hydrocarbons (PAHs) in biota samples such as oysters, mussels and fish liver. In this sense, once the samples were extracted--essentially with acetone and in a microwave system--and before they could be analysed by gas chromatography-mass spectrometry (GC-MS), three different approaches were studied for the clean-up step: solid phase extraction (SPE), microwave-assisted saponification (MAS) and gel permeation chromatography (GPC). The main aim of this work was to maximise the recoveries of PAHs and to minimise the presence of interfering compounds in the last extract. In the case of SPE, Florisil cartridges of 1, 2 and 5 g, and silica cartridges of 5 g were studied. In that case, and with oysters and mussels, microwave-assisted extraction and 5 g Florisil cartridges provided good results. In addition, the concentrations obtained for Standard Reference Material (SRM) NIST 2977 (mussel tissue) were in good agreement with the certified values. In the case of microwave-assisted saponification, the extracts were not as clean as those obtained with 5 g Florisil and this fact lead to overestimate the concentration of the heaviest PAHs. Finally, the cleanest extracts were obtained by GPC. The method was successfully applied to mussels, oysters and hake liver, and the results obtained for NIST 2977 (mussel tissue) were within the confidence interval of the certified reference material for most of the certified analytes.

High resolution isotopic analysis of U-bearing particles via fusion of SIMS and EDS images

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

Tarolli, Jay G.; Naes, Benjamin E.; Garcia, Benjamin J.

Image fusion of secondary ion mass spectrometry (SIMS) images and X-ray elemental maps from energy-dispersive spectroscopy (EDS) was performed to facilitate the isolation and re-analysis of isotopically unique U-bearing particles where the highest precision SIMS measurements are required. Image registration, image fusion and particle micromanipulation were performed on a subset of SIMS images obtained from a large area pre-screen of a particle distribution from a sample containing several certified reference materials (CRM) U129A, U015, U150, U500 and U850, as well as a standard reference material (SRM) 8704 (Buffalo River Sediment) to simulate particles collected on swipes during routine inspections ofmore » declared uranium enrichment facilities by the International Atomic Energy Agency (IAEA). In total, fourteen particles, ranging in size from 5 – 15 µm, were isolated and re-analyzed by SIMS in multi-collector mode identifying nine particles of CRM U129A, one of U150, one of U500 and three of U850. These identifications were made within a few percent errors from the National Institute of Standards and Technology (NIST) certified atom percent values for 234U, 235U and 238U for the corresponding CRMs. This work represents the first use of image fusion to enhance the accuracy and precision of isotope ratio measurements for isotopically unique U-bearing particles for nuclear safeguards applications. Implementation of image fusion is essential for the identification of particles of interests that fall below the spatial resolution of the SIMS images.« less

Systems biology approach to developing S(2)RM-based "systems therapeutics" and naturally induced pluripotent stem cells.

PubMed

Maguire, Greg; Friedman, Peter

2015-05-26

The degree to, and the mechanisms through, which stem cells are able to build, maintain, and heal the body have only recently begun to be understood. Much of the stem cell's power resides in the release of a multitude of molecules, called stem cell released molecules (SRM). A fundamentally new type of therapeutic, namely "systems therapeutic", can be realized by reverse engineering the mechanisms of the SRM processes. Recent data demonstrates that the composition of the SRM is different for each type of stem cell, as well as for different states of each cell type. Although systems biology has been successfully used to analyze multiple pathways, the approach is often used to develop a small molecule interacting at only one pathway in the system. A new model is emerging in biology where systems biology is used to develop a new technology acting at multiple pathways called "systems therapeutics". A natural set of healing pathways in the human that uses SRM is instructive and of practical use in developing systems therapeutics. Endogenous SRM processes in the human body use a combination of SRM from two or more stem cell types, designated as S(2)RM, doing so under various state dependent conditions for each cell type. Here we describe our approach in using state-dependent SRM from two or more stem cell types, S(2)RM technology, to develop a new class of therapeutics called "systems therapeutics." Given the ubiquitous and powerful nature of innate S(2)RM-based healing in the human body, this "systems therapeutic" approach using S(2)RM technology will be important for the development of anti-cancer therapeutics, antimicrobials, wound care products and procedures, and a number of other therapeutics for many indications.

Longitudinal change in quantitative meniscus measurements in knee osteoarthritis--data from the Osteoarthritis Initiative.

PubMed

Bloecker, Katja; Wirth, W; Guermazi, A; Hitzl, W; Hunter, D J; Eckstein, F

2015-10-01

We aimed to apply 3D MRI-based measurement technology to studying 2-year change in quantitative measurements of meniscus size and position. Forty-seven knees from the Osteoarthritis Initiative with medial radiographic joint space narrowing had baseline and 2-year follow-up MRIs. Quantitative measures were obtained from manual segmentation of the menisci and tibia using coronal DESSwe images. The standardized response mean (SRM = mean/SD change) was used as measure of sensitivity to longitudinal change. Medial tibial plateau coverage decreased from 34.8% to 29.9% (SRM -0.82; p < 0.001). Change in medial meniscus extrusion in a central image (SRM 0.18) and in the central five slices (SRM 0.22) did not reach significance, but change in extrusion across the entire meniscus (SRM 0.32; p = 0.03) and in the relative area of meniscus extrusion (SRM 0.56; p < 0.001) did. There was a reduction in medial meniscus volume (10%; p < 0.001), width (7%; p < 0.001), and height (2%; p = 0.08); meniscus substance loss was strongest in the posterior (SRM -0.51; p = 0.001) and weakest in the anterior horn (SRM -0.15; p = 0.31). This pilot study reports, for the first time, longitudinal change in quantitative 3D meniscus measurements in knee osteoarthritis. It provides evidence of improved sensitivity to change of 3D measurements compared with single slice analysis. • First longitudinal MRI-based measurements of change of meniscus position and size. • Quantitative longitudinal evaluation of meniscus change in knee osteoarthritis. • Improved sensitivity to change of 3D measurements compared with single slice analysis.

Bandwidth and Detection of Packet Length Covert Channels

DTIC Science & Technology

2011-03-01

Shared Resource Matrix ( SRM ): Develop a matrix of all resources on one side and on the other all the processes. Then, determine which process uses which...system calls. This method is similar to that of the SRM . Covert channels have also been created by modulating packet timing, data and headers of net- work...analysis, noninterference analysis, SRM method, and the covert flow tree method [4]. These methods can be used during the design phase of a system. Less

A case study of multi-seam coal mine entry stability analysis with strength reduction method

PubMed Central

Tulu, Ihsan Berk; Esterhuizen, Gabriel S; Klemetti, Ted; Murphy, Michael M.; Sumner, James; Sloan, Michael

2017-01-01

In this paper, the advantage of using numerical models with the strength reduction method (SRM) to evaluate entry stability in complex multiple-seam conditions is demonstrated. A coal mine under variable topography from the Central Appalachian region is used as a case study. At this mine, unexpected roof conditions were encountered during development below previously mined panels. Stress mapping and observation of ground conditions were used to quantify the success of entry support systems in three room-and-pillar panels. Numerical model analyses were initially conducted to estimate the stresses induced by the multiple-seam mining at the locations of the affected entries. The SRM was used to quantify the stability factor of the supported roof of the entries at selected locations. The SRM-calculated stability factors were compared with observations made during the site visits, and the results demonstrate that the SRM adequately identifies the unexpected roof conditions in this complex case. It is concluded that the SRM can be used to effectively evaluate the likely success of roof supports and the stability condition of entries in coal mines. PMID:28239503

A case study of multi-seam coal mine entry stability analysis with strength reduction method.

PubMed

Tulu, Ihsan Berk; Esterhuizen, Gabriel S; Klemetti, Ted; Murphy, Michael M; Sumner, James; Sloan, Michael

2016-03-01

In this paper, the advantage of using numerical models with the strength reduction method (SRM) to evaluate entry stability in complex multiple-seam conditions is demonstrated. A coal mine under variable topography from the Central Appalachian region is used as a case study. At this mine, unexpected roof conditions were encountered during development below previously mined panels. Stress mapping and observation of ground conditions were used to quantify the success of entry support systems in three room-and-pillar panels. Numerical model analyses were initially conducted to estimate the stresses induced by the multiple-seam mining at the locations of the affected entries. The SRM was used to quantify the stability factor of the supported roof of the entries at selected locations. The SRM-calculated stability factors were compared with observations made during the site visits, and the results demonstrate that the SRM adequately identifies the unexpected roof conditions in this complex case. It is concluded that the SRM can be used to effectively evaluate the likely success of roof supports and the stability condition of entries in coal mines.

Storage resource manager

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

Perelmutov, T.; Bakken, J.; Petravick, D.

Storage Resource Managers (SRMs) are middleware components whose function is to provide dynamic space allocation and file management on shared storage components on the Grid[1,2]. SRMs support protocol negotiation and reliable replication mechanism. The SRM standard supports independent SRM implementations, allowing for a uniform access to heterogeneous storage elements. SRMs allow site-specific policies at each location. Resource Reservations made through SRMs have limited lifetimes and allow for automatic collection of unused resources thus preventing clogging of storage systems with ''orphan'' files. At Fermilab, data handling systems use the SRM management interface to the dCache Distributed Disk Cache [5,6] and themore » Enstore Tape Storage System [15] as key components to satisfy current and future user requests [4]. The SAM project offers the SRM interface for its internal caches as well.« less

Space Shuttle SRM development. [Solid Rocket Motors

NASA Technical Reports Server (NTRS)

Brinton, B. C.; Kilminster, J. C.

1979-01-01

The successful static test of the fourth Development Space Shuttle Solid Rocket Motor (SRM) in February 1979 concluded the development testing phase of the SRM Project. Qualification and flight motors are currently being fabricated, with the first qualification motor to be static tested. Delivered thrust-time traces on all development motors were very close to predicted values, and both specific and total impulse exceeded specification requirements. 'All-up' static tests conducted with a solid rocket booster equipment on development motors achieved all test objectives. Transportation and support equipment concepts have been proven, baselining is complete, and component reusability has been demonstrated. Evolution of the SRM transportation support equipment, and special test equipment designs are reviewed, and development activities discussed. Handling and processing aspects of large, heavy components are described.

Analysis of Rare Earth Elements in Uranium Using Handheld Laser-Induced Breakdown Spectroscopy (HH LIBS)

DOE PAGES

Manard, Benjamin T.; Wylie, E. Miller; Willson, Stephen P.

2018-05-22

In this paper, a portable handheld laser-induced breakdown spectroscopy (HH LIBS) instrument was evaluated as a rapid method to qualitatively analyze rare earth elements in a uranium oxide matrix. This research is motivated by the need for development of a method to perform rapid, at-line chemical analysis in a nuclear facility, particularly to provide a rapid first pass analysis to determine if additional actions or measurements are warranted. This will result in the minimization of handling and transport of radiological and nuclear material and subsequent exposure to their associated hazards. In this work, rare earth elements (Eu, Nd, and Yb)more » were quantitatively spiked into a uranium oxide powder and analyzed by the HH LIBS instrumentation. This method demonstrates the ability to rapidly identify elemental constituents in sub-percent levels in a uranium matrix. Preliminary limits of detection (LODs) were determined with values on the order of hundredths of a percent. Validity of this methodology was explored by employing a National Institute of Standards and Technology (NIST) standard reference materials (SRM) 610 and 612 (Trace Elements in Glass). Finally, it was determined that the HH LIBS method was able to clearly discern the rare earths elements of interest in the glass or uranium matrices.« less

Analysis of Rare Earth Elements in Uranium Using Handheld Laser-Induced Breakdown Spectroscopy (HH LIBS)

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

Manard, Benjamin T.; Wylie, E. Miller; Willson, Stephen P.

In this paper, a portable handheld laser-induced breakdown spectroscopy (HH LIBS) instrument was evaluated as a rapid method to qualitatively analyze rare earth elements in a uranium oxide matrix. This research is motivated by the need for development of a method to perform rapid, at-line chemical analysis in a nuclear facility, particularly to provide a rapid first pass analysis to determine if additional actions or measurements are warranted. This will result in the minimization of handling and transport of radiological and nuclear material and subsequent exposure to their associated hazards. In this work, rare earth elements (Eu, Nd, and Yb)more » were quantitatively spiked into a uranium oxide powder and analyzed by the HH LIBS instrumentation. This method demonstrates the ability to rapidly identify elemental constituents in sub-percent levels in a uranium matrix. Preliminary limits of detection (LODs) were determined with values on the order of hundredths of a percent. Validity of this methodology was explored by employing a National Institute of Standards and Technology (NIST) standard reference materials (SRM) 610 and 612 (Trace Elements in Glass). Finally, it was determined that the HH LIBS method was able to clearly discern the rare earths elements of interest in the glass or uranium matrices.« less

Analysis of Rare Earth Elements in Uranium Using Handheld Laser-Induced Breakdown Spectroscopy (HH LIBS).

PubMed

Manard, Benjamin T; Wylie, E Miller; Willson, Stephen P

2018-01-01

A portable handheld laser-induced breakdown spectroscopy (HH LIBS) instrument was evaluated as a rapid method to qualitatively analyze rare earth elements in a uranium oxide matrix. This research is motivated by the need for development of a method to perform rapid, at-line chemical analysis in a nuclear facility, particularly to provide a rapid first pass analysis to determine if additional actions or measurements are warranted. This will result in the minimization of handling and transport of radiological and nuclear material and subsequent exposure to their associated hazards. In this work, rare earth elements (Eu, Nd, and Yb) were quantitatively spiked into a uranium oxide powder and analyzed by the HH LIBS instrumentation. This method demonstrates the ability to rapidly identify elemental constituents in sub-percent levels in a uranium matrix. Preliminary limits of detection (LODs) were determined with values on the order of hundredths of a percent. Validity of this methodology was explored by employing a National Institute of Standards and Technology (NIST) standard reference materials (SRM) 610 and 612 (Trace Elements in Glass). It was determined that the HH LIBS method was able to clearly discern the rare earths elements of interest in the glass or uranium matrices.

Structural behavior of the space shuttle SRM Tang-Clevis joint

NASA Technical Reports Server (NTRS)

Greene, W. H.; Knight, N. F., Jr.; Stockwell, A. E.

1986-01-01

The space shuttle Challenger accident investigation focused on the failure of a tang-clevis joint on the right solid rocket motor. The existence of relative motion between the inner arm of the clevis and the O-ring sealing surface on the tang has been identified as a potential contributor to this failure. This motion can cause the O-rings to become unseated and therefore lose their sealing capability. Finite element structural analyses have been performed to predict both deflections and stresses in the joint under the primary, pressure loading condition. These analyses have demonstrated the difficulty of accurately predicting the structural behavior of the tang-clevis joint. Stresses in the vicinity of the connecting pins, obtained from elastic analyses, considerably exceed the material yield allowables indicating that inelastic analyses are probably necessary. Two modifications have been proposed to control the relative motion between the inner clevis arm and the tang at the O-ring sealing surface. One modification, referred to as the capture feature, uses additional material on the inside of the tang to restrict motion of the inner clevis arm. The other modification uses external stiffening rings above and below the joint to control the local bending in the shell near the joint. Both of these modifications are shown to be effective in controlling the relative motion in the joint.

Structural behavior of the space shuttle SRM tang-clevis joint

NASA Technical Reports Server (NTRS)

Greene, William H.; Knight, Norman F., Jr.; Stockwell, Alan E.

1988-01-01

The space shuttle Challenger accident investigation focused on the failure of a tang-clevis joint on the right solid rocket motor. The existence of relative motion between the inner arm of the clevis and the O-ring sealing surface on the tang has been identified as a potential contributor to this failure. This motion can cause the O-rings to become unseated and therefore lose their sealing capability. Finite element structural analyses have been performed to predict both deflections and stresses in the joint under the primary, pressure loading condition. These analyses have demonstrated the difficulty of accurately predicting the structural behavior of the tang-clevis joint. Stresses in the vicinity of the connecting pins, obtained from elastic analyses, considerably exceed the material yield allowables indicating that inelastic analyses are probably necessary. Two modifications have been proposed to control the relative motion between the inner clevis arm and the tang at the O-ring sealing surface. One modification, referred to as the capture feature, uses additional material on the inside of the tang to restrict motion of the inner clevis arm. The other modification uses external stiffening rings above and below the joint to control the local bending in the shell near the joint. Both of these modifications are shown to be effective in controlling the relative motion in the joint.

X-ray Fluorescence Spectroscopy Study of Coating Thickness and Base Metal Composition

NASA Technical Reports Server (NTRS)

Rolin, T. D.; Leszczuk, Y.

2008-01-01

For electrical, electronic, and electromechanical (EEE) parts to be approved for space use, they must be able to meet safety standards approved by NASA. A fast, reliable, and precise method is needed to make sure these standards are met. Many EEE parts are coated in gold (Au) and nickel (Ni), and the thickness coating is crucial to a part s performance. A nondestructive method that is efficient in measuring coating thickness is x-ray fluorescence (XRF) spectroscopy. The XRF spectrometer is a machine designed to measure layer thickness and composition of single or multilayered samples. By understanding the limitations in the collection of the data by this method, accurate composition and thickness measurements can be obtained for samples with Au and Ni coatings. To understand the limitations of data found, measurements were taken with the XRF spectrometer and compared to true values of standard reference materials (SRM) that were National Institute of Standards and Technology (NIST) traceable. For every sample, six different parameters were varied to understand measurement error: coating/substrate combination, number of layers, counting interval, collimator size, coating thickness, and test area location. Each measurement was taken in accordance with standards set by the American Society for Testing and Materials (ASTM) International Standard B 568.

SRB Materials and Processes Assessment from Laboratory and Ocean Environmental Tests

NASA Technical Reports Server (NTRS)

1978-01-01

The Materials and Processes Laboratory evaluation of Solid Rocket Boosters (SRB) and Solid Rocket Motors (SRM) candidate material, both in-house and with ocean exposure tests at Panama City and Kennedy Space Center (KSC), Florida is presented. Early sample tests showed excellent seawater corrosion resistance for inconel 718 and titanium 6A1-4V alloys. Considerable corrosion and biofouling occurred with bare 2219-T87 aluminum. Subsequent tests conclusively demonstrated that epoxy coatings prevented corrosion of 2219-T87 aluminum as long as the coatings stays intact. The results and assessment of the series of ocean environmental tests that were conducted are also presented.

How well could existing sensors detect the deployment of a solar radiation management (SRM) geoengineering effort?

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

Hurd, Alan J.

2016-04-29

While the stated reason for asking this question is “to understand better our ability to warn policy makers in the unlikely event of an unanticipated SRM geoengineering deployment or large-scale field experiment”, my colleagues and I felt that motives would be important context because the scale of any meaningful SRM deployment would be so large that covert deployment seems impossible. However, several motives emerged that suggest a less-than-global effort might be important.

SU-D-9A-02: Relative Effects of Threshold Choice and Spatial Resolution Modeling On SUV and Volume Quantification in F18-FDG PET Imaging of Anal Cancer Patients

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

Zhao, F; Shandong Cancer Hospital and Insititute, Jinan, Shandong; Bowsher, J

2014-06-01

Purpose: PET imaging with F18-FDG is utilized for treatment planning, treatment assessment, and prognosis. A region of interest (ROI) encompassing the tumor may be determined on the PET image, often by a threshold T on the PET standard uptake values (SUVs). Several studies have shown prognostic value for relevant ROI properties including maximum SUV value (SUVmax), metabolic tumor volume (MTV), and total glycolytic activity (TGA). The choice of threshold T may affect mean SUV value (SUVmean), MTV, and TGA. Recently spatial resolution modeling (SRM) has been introduced on many PET systems. SRM may also affect these ROI properties. The purposemore » of this work is to investigate the relative influence of SRM and threshold choice T on SUVmean, MTV, TGA, and SUVmax. Methods: For 9 anal cancer patients, 18F-FDG PET scans were performed prior to treatment. PET images were reconstructed by 2 iterations of Ordered Subsets Expectation Maximization (OSEM), with and without SRM. ROI contours were generated by 5 different SUV threshold values T: 2.5, 3.0, 30%, 40%, and 50% of SUVmax. Paired-samples t tests were used to compare SUVmean, MTV, and TGA (a) for SRM on versus off and (b) between each pair of threshold values T. SUVmax was also compared for SRM on versus off. Results: For almost all (57/60) comparisons of 2 different threshold values, SUVmean, MTV, and TGA showed statistically significant variation. For comparison of SRM on versus off, there were no statistically significant changes in SUVmax and TGA, but there were statistically significant changes in MTV for T=2.5 and T=3.0 and in SUVmean for all T. Conclusion: The near-universal statistical significance of threshold choice T suggests that, regarding harmonization across sites, threshold choice may be a greater concern than choice of SRM. However, broader study is warranted, e.g. other iterations of OSEM should be considered.« less

Assessment of trace element contents of chicken products from Turkey.

PubMed

Uluozlu, Ozgur Dogan; Tuzen, Mustafa; Mendil, Durali; Soylak, Mustafa

2009-04-30

Due to the consumption of chicken and chicken products in Turkey at high ratio, trace metal content of chicken and chicken products from Turkey were determined by atomic absorption spectrometry after microwave digestion. The accuracy of the method was confirmed by analysis of standard reference material (NIST SRM 1577b Bovine liver). Trace element content in various parts of chicken samples and chicken products were to be in the range of 0.10-114 microg/g for copper, 0.25-6.09 microg/kg for cadmium, 0.01-0.40 microg/g for lead, 0.10-0.91 microg/g for selenium, 0.05-3.91 microg/g for manganese, 0.06-0.10 microg/g for arsenic, 0.01-0.72 microg/g for chromium, 0.01-2.08 microg/g for nickel, 0.01-0.02 microg/g for cobalt, 0.10-1.90 microg/g for aluminium, 1.21-24.3 microg/g for zinc, 2.91-155 microg/g for iron. The levels of lead in some analyzed chicken products were higher than the recommended legal limits for human consumption.

A green and efficient procedure for the preconcentration and determination of cadmium, nickel and zinc from freshwater, hemodialysis solutions and tuna fish samples by cloud point extraction and flame atomic absorption spectrometry.

PubMed

Galbeiro, Rafaela; Garcia, Samara; Gaubeur, Ivanise

2014-04-01

Cloud point extraction (CPE) was used to simultaneously preconcentrate trace-level cadmium, nickel and zinc for determination by flame atomic absorption spectrometry (FAAS). 1-(2-Pyridilazo)-2-naphthol (PAN) was used as a complexing agent, and the metal complexes were extracted from the aqueous phase by the surfactant Triton X-114 ((1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol). Under optimized complexation and extraction conditions, the limits of detection were 0.37μgL(-1) (Cd), 2.6μgL(-1) (Ni) and 2.3μgL(-1) (Zn). This extraction was quantitative with a preconcentration factor of 30 and enrichment factor estimated to be 42, 40 and 43, respectively. The method was applied to different complex samples, and the accuracy was evaluated by analyzing a water standard reference material (NIST SRM 1643e), yielding results in agreement with the certified values. Copyright © 2013 Elsevier GmbH. All rights reserved.

Application of an automatic thermal desorption-gas chromatography-mass spectrometry system for the analysis of polycyclic aromatic hydrocarbons in airborne particulate matter.

PubMed

Gil-Moltó, J; Varea, M; Galindo, N; Crespo, J

2009-02-27

The application of the thermal desorption (TD) method coupled with gas chromatography-mass spectrometry (GC-MS) to the analysis of aerosol organics has been the focus of many studies in recent years. This technique overcomes the main drawbacks of the solvent extraction approach such as the use of large amounts of toxic organic solvents and long and laborious extraction processes. In this work, the application of an automatic TD-GC-MS instrument for the determination of particle-bound polycyclic aromatic hydrocarbons (PAHs) is evaluated. This device offers the advantage of allowing the analysis of either gaseous or particulate organics without any modification. Once the thermal desorption conditions for PAH extraction were optimised, the method was verified on NIST standard reference material (SRM) 1649a urban dust, showing good linearity, reproducibility and accuracy for all target PAHs. The method has been applied to PM10 and PM2.5 samples collected on quartz fibre filters with low volume samplers, demonstrating its capability to quantify PAHs when only a small amount of sample is available.

Vortex-assisted switchable liquid-liquid microextraction for the preconcentration of cadmium in environmental samples prior to its determination with flame atomic absorption spectrometry.

PubMed

Fırat, Merve; Bodur, Süleyman; Tışlı, Büşra; Özlü, Cansu; Chormey, Dotse Selali; Turak, Fatma; Bakırdere, Sezgin

2018-06-12

In this study, a switchable solvent was used to preconcentrate trace amounts of Cd from aqueous solution for its determination by flame atomic absorption spectrometry (FAAS). Protonation of N,N-dimethylbenzylamine by dry ice (solid CO 2 ) made it water soluble, and addition of sodium hydroxide converted it back to its original nonionic state for phase separation and subsequent extraction of Cd. A slotted quartz tube (SQT) was attached to the flame burner head to increase the residence time of Cd atoms in the light path. Under the optimum conditions, limits of detection and quantification were determined as 0.7 and 2.6 μg L -1 , respectively. Low relative standard deviations calculated from seven replicate measurements of the lowest concentration indicated high precision. Accuracy of the developed method was checked by using a standard reference material (SRM 1633c). Spiked recovery tests were also performed on lake water and wastewater samples at different concentrations to check the applicability of the developed method, and the results obtained (90-103%) established high recovery.

Application of solid phase extraction on multiwalled carbon nanotubes of some heavy metal ions to analysis of skin whitening cosmetics using ICP-AES.

PubMed

Alqadami, Ayoub A; Abdalla, Mohammad Abulhassan; AlOthman, Zeid A; Omer, Kamal

2013-01-14

A novel and highly sensitive method for the determination of some heavy metals in skin whitening cosmetics creams using multiwalled carbon nanotubes MWCNTs as solid phase extraction sorbent for the preconcentration of these heavy metals prior to their determination by inductively coupled plasma atomic emission spectrometry is described. Different practical parameters have been thoroughly investigated and the optimum experimental conditions were employed. The developed method was then applied for the determination of arsenic, bismuth, cadmium, mercury, lead and titanium in samples of skin whitening cosmetics. The detection limits under these conditions for As, Bi, Cd, Pb, Hg and Ti were 2.4, 4.08, 0.3, 2.1, 1.8, and 1.8 ng·mL-1, respectively. The relative standard deviations (RSDs) were found to be less than 2.0%. For validation, a certified reference material of NIST SRM 1570a spinach leaves was analyzed and the determined values were in good agreement with the certified values. The recoveries for spiked samples were found to be in the range of 89.6-104.4%.

Ultrasound-assisted ionic liquid dispersive liquid-liquid microextraction combined with graphite furnace atomic absorption spectrometric for selenium speciation in foods and beverages.

PubMed

Tuzen, Mustafa; Pekiner, Ozlem Zeynep

2015-12-01

A rapid and environmentally friendly ultrasound assisted ionic liquid dispersive liquid liquid microextraction (USA-IL-DLLME) was developed for the speciation of inorganic selenium in beverages and total selenium in food samples by using graphite furnace atomic absorption spectrometry. Some analytical parameters including pH, amount of complexing agent, extraction time, volume of ionic liquid, sample volume, etc. were optimized. Matrix effects were also investigated. Enhancement factor (EF) and limit of detection (LOD) for Se(IV) were found to be 150 and 12 ng L(-1), respectively. The relative standard deviation (RSD) was found 4.2%. The accuracy of the method was confirmed with analysis of LGC 6010 Hard drinking water and NIST SRM 1573a Tomato leaves standard reference materials. Optimized method was applied to ice tea, soda and mineral water for the speciation of Se(IV) and Se(VI) and some food samples including beer, cow's milk, red wine, mixed fruit juice, date, apple, orange, grapefruit, egg and honey for the determination of total selenium. Copyright © 2015 Elsevier Ltd. All rights reserved.

A new method of UA_CPE coupled with spectrophotometry for the faster and cost-effective detection of proline in fruit juice, honey, and wine.

PubMed

Dağdeviren, Semahat; Altunay, Nail; Sayman, Yasin; Gürkan, Ramazan

2018-07-30

The study developed a new method for proline detection in honey, wine and fruit juice using ultrasound assisted-cloud point extraction (UA-CPE) and spectrophotometry. Initially, a quaternary complex was built, containing proline, histamine, Cu(II), and fluorescein at pH 5.5. Samples were treated with ethanol-water mixture before extraction and preconcentration, using an ultrasonic bath for 10 min at 40 °C (40 kHz, 300 W). After the optimization of variables affecting extraction efficiency, good linearity was obtained between 15 and 600 µg L -1 with sensitivity enhancement factor of 105. The limits of detection and quantification were 5.7 and 19.0 µg L -1 , respectively. The recovery percentage and relative standard deviations (RSD %) were between 95.3 and 103.3%, and 2.5 and 4.2%, respectively. The accuracy of the method was verified by the analysis of a standard reference material (SRM 2389a). Copyright © 2018 Elsevier Ltd. All rights reserved.

Gravimetric Analysis of Particulate Matter using Air Samplers Housing Internal Filtration Capsules.

PubMed

O'Connor, Sean; O'Connor, Paula Fey; Feng, H Amy; Ashley, Kevin

2014-10-01

An evaluation was carried out to investigate the suitability of polyvinyl chloride (PVC) internal capsules, housed within air sampling devices, for gravimetric analysis of airborne particles collected in workplaces. Experiments were carried out using blank PVC capsules and PVC capsules spiked with 0,1 - 4 mg of National Institute of Standards and Technology Standard Reference Material ® (NIST SRM) 1648 (Urban Particulate Matter) and Arizona Road Dust (Air Cleaner Test Dust). The capsules were housed within plastic closed-face cassette samplers (CFCs). A method detection limit (MDL) of 0,075 mg per sample was estimated. Precision S r at 0,5 - 4 mg per sample was 0,031 and the estimated bias was 0,058. Weight stability over 28 days was verified for both blanks and spiked capsules. Independent laboratory testing on blanks and field samples verified long-term weight stability as well as sampling and analysis precision and bias estimates. An overall precision estimate Ŝ rt of 0,059 was obtained. An accuracy measure of ±15,5% was found for the gravimetric method using PVC internal capsules.

Isotope ratio analysis of individual sub-micrometer plutonium particles with inductively coupled plasma mass spectrometry.

PubMed

Esaka, Fumitaka; Magara, Masaaki; Suzuki, Daisuke; Miyamoto, Yutaka; Lee, Chi-Gyu; Kimura, Takaumi

2010-12-15

Information on plutonium isotope ratios in individual particles is of great importance for nuclear safeguards, nuclear forensics and so on. Although secondary ion mass spectrometry (SIMS) is successfully utilized for the analysis of individual uranium particles, the isobaric interference of americium-241 to plutonium-241 makes difficult to obtain accurate isotope ratios in individual plutonium particles. In the present work, an analytical technique by a combination of chemical separation and inductively coupled plasma mass spectrometry (ICP-MS) is developed and applied to isotope ratio analysis of individual sub-micrometer plutonium particles. The ICP-MS results for individual plutonium particles prepared from a standard reference material (NBL SRM-947) indicate that the use of a desolvation system for sample introduction improves the precision of isotope ratios. In addition, the accuracy of the (241)Pu/(239)Pu isotope ratio is much improved, owing to the chemical separation of plutonium and americium. In conclusion, the performance of the proposed ICP-MS technique is sufficient for the analysis of individual plutonium particles. Copyright © 2010 Elsevier B.V. All rights reserved.

Gravimetric Analysis of Particulate Matter using Air Samplers Housing Internal Filtration Capsules

PubMed Central

O'Connor, Sean; O'Connor, Paula Fey; Feng, H. Amy

2015-01-01

Summary An evaluation was carried out to investigate the suitability of polyvinyl chloride (PVC) internal capsules, housed within air sampling devices, for gravimetric analysis of airborne particles collected in workplaces. Experiments were carried out using blank PVC capsules and PVC capsules spiked with 0,1 – 4 mg of National Institute of Standards and Technology Standard Reference Material® (NIST SRM) 1648 (Urban Particulate Matter) and Arizona Road Dust (Air Cleaner Test Dust). The capsules were housed within plastic closed-face cassette samplers (CFCs). A method detection limit (MDL) of 0,075 mg per sample was estimated. Precision Sr at 0,5 - 4 mg per sample was 0,031 and the estimated bias was 0,058. Weight stability over 28 days was verified for both blanks and spiked capsules. Independent laboratory testing on blanks and field samples verified long-term weight stability as well as sampling and analysis precision and bias estimates. An overall precision estimate Ŝrt of 0,059 was obtained. An accuracy measure of ±15,5% was found for the gravimetric method using PVC internal capsules. PMID:26435581

Status of emerging standards for removable computer storage media and related contributions of NIST

NASA Technical Reports Server (NTRS)

Podio, Fernando L.

1992-01-01

Standards for removable computer storage media are needed so that users may reliably interchange data both within and among various computer installations. Furthermore, media interchange standards support competition in industry and prevent sole-source lock-in. NIST participates in magnetic tape and optical disk standards development through Technical Committees X3B5, Digital Magnetic Tapes, X3B11, Optical Digital Data Disk, and the Joint Technical Commission on Data Permanence. NIST also participates in other relevant national and international standards committees for removable computer storage media. Industry standards for digital magnetic tapes require the use of Standard Reference Materials (SRM's) developed and maintained by NIST. In addition, NIST has been studying care and handling procedures required for digital magnetic tapes. NIST has developed a methodology for determining the life expectancy of optical disks. NIST is developing care and handling procedures for optical digital data disks and is involved in a program to investigate error reporting capabilities of optical disk drives. This presentation reflects the status of emerging magnetic tape and optical disk standards, as well as NIST's contributions in support of these standards.

Design and Experimental Study on Spinning Solid Rocket Motor

NASA Astrophysics Data System (ADS)

Xue, Heng; Jiang, Chunlan; Wang, Zaicheng

The study on spinning solid rocket motor (SRM) which used as power plant of twice throwing structure of aerial submunition was introduced. This kind of SRM which with the structure of tangential multi-nozzle consists of a combustion chamber, propellant charge, 4 tangential nozzles, ignition device, etc. Grain design, structure design and prediction of interior ballistic performance were described, and problem which need mainly considered in design were analyzed comprehensively. Finally, in order to research working performance of the SRM, measure pressure-time curve and its speed, static test and dynamic test were conducted respectively. And then calculated values and experimental data were compared and analyzed. The results indicate that the designed motor operates normally, and the stable performance of interior ballistic meet demands. And experimental results have the guidance meaning for the pre-research design of SRM.

Engaging the Global South on climate engineering research

NASA Astrophysics Data System (ADS)

Winickoff, David E.; Flegal, Jane A.; Asrat, Asfawossen

2015-07-01

The Global South is relatively under-represented in public deliberations about solar radiation management (SRM), a controversial climate engineering concept. This Perspective analyses the outputs of a deliberative exercise about SRM, which took place at the University of California-Berkeley and involved 45 mid-career environmental leaders, 39 of whom were from the Global South. This analysis identifies and discusses four themes from the Berkeley workshop that might inform research and governance in this arena: (1) the 'moral hazard' problem should be reframed to emphasize 'moral responsibility'; (2) climate models of SRM deployment may not be credible as primary inputs to policy because they cannot sufficiently address local concerns such as access to water; (3) small outdoor experiments require some form of international public accountability; and (4) inclusion of actors from the Global South will strengthen both SRM research and governance.

KSC technicians use propellant slump measurement tool on ATA SRM

NASA Technical Reports Server (NTRS)

1988-01-01

Kennedy Space Center (KSC) technicians use new propellant slump measurement tool on the Assembly Test Article (ATA) aft solid rocket motor (SRM). The tool measures any slumping of the top of the solid rocket booster (SRB) solid propellant. Data gathered by this tool and others during the ATA test will be analyzed by SRM engineers. Astronaut Stephen S. Oswald at far right (barely visible) and Morton Thiokol supervisor Howard Fichtl look on during the data gathering process. The month-long ATA test is designed to evaluate the performance of new tools required to put the tighter fitting redesigned SRM joints together. In addition, new procedures are being used and ground crews are receiving training in preparation for stacking the STS-26 flight set of motors. View provided by KSC with alternate number KSC-87PC-956.

Determination of mercury in SRM crude oils and refined products by isotope dilution cold vapor ICP-MS using closed-system combustion.

PubMed

Kelly, W Robert; Long, Stephen E; Mann, Jacqueline L

2003-07-01

Mercury was determined by isotope dilution cold-vapor inductively coupled plasma mass spectrometry (ID-CV-ICP-MS) in four different liquid petroleum SRMs. Samples of approximately 0.3 g were spiked with stable (201)Hg and wet ashed in a closed system (Carius tube) using 6 g of high-purity nitric acid. Three different types of commercial oils were measured: two Texas crude oils, SRM 2721 (41.7+/-5.7 pg g(-1)) and SRM 2722 (129+/-13 pg g(-1)), a low-sulfur diesel fuel, SRM 2724b (34+/-26 pg g(-1)), and a low-sulfur residual fuel oil, SRM 1619b (3.5+/-0.74 ng g(-1)) (mean value and 95% CI). The Hg values for the crude oils and the diesel fuel are the lowest values ever reported for these matrices. The method detection limit, which is ultimately limited by method blank uncertainty, is approximately 10 pg g(-1) for a 0.3 g sample. Accurate Hg measurements in petroleum products are needed to assess the contribution to the global Hg cycle and may be needed in the near future to comply with reporting regulations for toxic elements.

Study of solid rocket motors for a space shuttle booster. Appendix C: Recovery and reuse 120-inch diameter solid rocket motor boosters

NASA Technical Reports Server (NTRS)

1972-01-01

A baseline for a space shuttle configuration utilizing four parallel-burn 120-in. diameter SRMS is presented. Topics discussed include parachute system sequence, recovery system development profile, parachute container, and segment and closure recovery operations. A cost analysis for recovery of the SRM stage is presented. It is concluded that from the standpoint of minimum cost and development, parachutes are the best means of achieving SRM recovery. Major SRM components can be reused safely.

Evaluation of bilirubin interference and accuracy of six creatinine assays compared with isotope dilution-liquid chromatography mass spectrometry.

PubMed

Nah, Hyunjin; Lee, Sang-Guk; Lee, Kyeong-Seob; Won, Jae-Hee; Kim, Hyun Ok; Kim, Jeong-Ho

2016-02-01

The aim of this study was to estimate bilirubin interference and accuracy of six routine methods for measuring creatinine compared with isotope dilution-liquid chromatography mass spectrometry (ID-LC/MS). A total of 40 clinical serum samples from 31 patients with serum total bilirubin concentration >68.4μmol/L were collected. Serum creatinine was measured using two enzymatic reagents and four Jaffe reagents as well as ID-LC/MS. Correlations between bilirubin concentration and percent difference in creatinine compared with ID-LC/MS were analyzed to investigate bilirubin interference. Bias estimations between the six reagents and ID-LC/MS were performed. Recovery tests using National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 967a were also performed. Both the enzymatic methods showed no bilirubin interference. However, three of the four Jaffe methods demonstrated significant bilirubin concentration-dependent interference in samples with creatinine levels <53μmol/L, and two of them showed significant bilirubin interference in samples with creatinine levels ranging from 53.0 to 97.2μmol/L. Comparison of these methods with ID-LC/MS using patients' samples with elevated bilirubin revealed that the tested methods failed to achieve the bias goal at especially low levels of creatinine. In addition, recovery test using NIST SRM 967a showed that bias in one Jaffe method and two enzymatic methods did not achieve the bias goal at either low or high level of creatinine, indicating they had calibration bias. One enzymatic method failed to achieve all the bias goals in both comparison experiment and recovery test. It is important to understand that both bilirubin interference and calibration traceability to ID-LC/MS should be considered to improve the accuracy of creatinine measurement. Copyright © 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Standardization of 63Ni by 4πβ Liquid Scintillation Spectrometry With 3H-Standard Efficiency Tracing

PubMed Central

Zimmerman, B. E.; Collé, R.

1997-01-01

The low energy (Eβmax = 66.945 keV ± 0.004 keV) β-emitter 63Ni has become increasingly important in the field of radionuclidic metrology. In addition to having a low β-endpoint energy, the relatively long half-life (101.1 a ± 1.4 a) makes it an appealing standard for such applications. This paper describes the recent preparation and calibration of a new solution Standard Reference Material of 63Ni, SRM 4226C, released by the National Institute of Standards and Technology. The massic activity CA for these standards was determined using 4πβ liquid scintillation (LS) spectrometry with 3H-standard efficiency tracing using the CIEMAT/NIST method, and is certified as 50.53 kBq ·g−1 ± 0.46 Bq · g−1 at the reference time of 1200 EST August 15, 1995. The uncertainty given is the expanded (coverage factor k = 2 and thus a 2 standard deviation estimate) uncertainty based on the evaluation of 28 different uncertainty components. These components were evaluated on the basis of an exhaustive number (976) of LS counting measurements investigating over 15 variables. Through the study of these variables it was found that LS cocktail water mass fraction and ion concentration play important roles in cocktail stability and consistency of counting results. The results of all of these experiments are discussed. PMID:27805155

Recalibrated Equations for Determining Effect of Oil Filtration on Rolling Bearing Life

NASA Technical Reports Server (NTRS)

Needelman, William M.; Zaretsky, Erwin V.

2014-01-01

In 1991, Needelman and Zaretsky presented a set of empirically derived equations for bearing fatigue life (adjustment) factors (LFs) as a function of oil filter ratings. These equations for life factors were incorporated into the reference book, "STLE Life Factors for Rolling Bearings." These equations were normalized (LF = 1) to a 10-micrometer filter rating at Beta(sub x) = 200 (normal cleanliness) as it was then defined. Over the past 20 years, these life factors based on oil filtration have been used in conjunction with ANSI/ABMA standards and bearing computer codes to predict rolling bearing life. Also, additional experimental studies have been made by other investigators into the relationship between rolling bearing life and the size, number, and type of particle contamination. During this time period filter ratings have also been revised and improved, and they now use particle counting calibrated to a new National Institute of Standards and Technology (NIST) reference material, NIST SRM 2806, 1997. This paper reviews the relevant bearing life studies and describes the new filter ratings. New filter ratings, Beta(sub x(c)) = 200 and Beta(sub x(c)) = 1000, are benchmarked to old filter ratings, Beta(sub x) = 200, and vice versa. Two separate sets of filter LF values were derived based on the new filter ratings for roller bearings and ball bearings, respectively. Filter LFs can be calculated for the new filter ratings.

Direct separation of boron from Na- and Ca-rich matrices by sublimation for stable isotope measurement by MC-ICP-MS.

PubMed

Wang, Bo-Shian; You, Chen-Feng; Huang, Kuo-Fang; Wu, Shein-Fu; Aggarwal, Suresh Kumar; Chung, Chuan-Hsiung; Lin, Pei-Ying

2010-09-15

An improved technique for precise and accurate determination of boron isotopic composition in Na-rich natural waters (groundwater, seawater) and marine biogenic carbonates was developed. This study used a 'micro-sublimation' technique to separate B from natural sample matrices in place of the conventional ion-exchange extraction. By adjusting analyte to appropriate pH, quantitative recovery of boron can be achieved (>98%) and the B procedural blank is limited to <8 pg. An additional mass bias effect in MC-ICP-MS was observed which could not be improved via the standard-sample-standard bracketing or the 'pseudo internal' normalization by Li. Therefore a standard other than NBS SRM 951 was used to monitor plasma condition in order to maintain analytical accuracy. An isotope cross-calibration with results from TIMS shows that the space-charge mass bias on MC-ICP-MS can be successfully corrected using off-line mathematical manipulation. Several reference materials, including the seawater IAPSO and two groundwater standards IAEA-B-2 and IAEA-B-3, were used to validate this approach. We found that the delta(11)B of the reference coral JCp-1 was 24.22+/-0.28 per thousand, corresponding to seawater pH based on the coral delta(11)B-pH function. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Quantification and Comparison of Anti-Fibrotic Therapies by Polarized SRM and SHG-Based Morphometry in Rat UUO Model

PubMed Central

Weldon, Steve M.; Matera, Damian; Lee, ChungWein; Yang, Haichun; Fryer, Ryan M.; Fogo, Agnes B.; Reinhart, Glenn A.

2016-01-01

Renal interstitial fibrosis (IF) is an important pathologic manifestation of disease progression in a variety of chronic kidney diseases (CKD). However, the quantitative and reproducible analysis of IF remains a challenge, especially in experimental animal models of progressive IF. In this study, we compare traditional polarized Sirius Red morphometry (SRM) to novel Second Harmonic Generation (SHG)-based morphometry of unstained tissues for quantitative analysis of IF in the rat 5 day unilateral ureteral obstruction (UUO) model. To validate the specificity of SHG for detecting fibrillar collagen components in IF, co-localization studies for collagens type I, III, and IV were performed using IHC. In addition, we examined the correlation, dynamic range, sensitivity, and ability of polarized SRM and SHG-based morphometry to detect an anti-fibrotic effect of three different treatment regimens. Comparisons were made across three separate studies in which animals were treated with three mechanistically distinct pharmacologic agents: enalapril (ENA, 15, 30, 60 mg/kg), mycophenolate mofetil (MMF, 2, 20 mg/kg) or the connective tissue growth factor (CTGF) neutralizing antibody, EX75606 (1, 3, 10 mg/kg). Our results demonstrate a strong co-localization of the SHG signal with fibrillar collagens I and III but not non-fibrillar collagen IV. Quantitative IF, calculated as percent cortical area of fibrosis, demonstrated similar response profile for both polarized SRM and SHG-based morphometry. The two methodologies exhibited a strong correlation across all three pharmacology studies (r2 = 0.89–0.96). However, compared with polarized SRM, SHG-based morphometry delivered a greater dynamic range and absolute magnitude of reduction of IF after treatment. In summary, we demonstrate that SHG-based morphometry in unstained kidney tissues is comparable to polarized SRM for quantitation of fibrillar collagens, but with an enhanced sensitivity to detect treatment-induced reductions in IF. Thus, performing SHG-based morphometry on unstained kidney tissue is a reliable alternative to traditional polarized SRM for quantitative analysis of IF. PMID:27257917

Impacts of stratospheric sulfate geoengineering on tropospheric ozone

NASA Astrophysics Data System (ADS)

Xia, Lili; Nowack, Peer J.; Tilmes, Simone; Robock, Alan

2017-10-01

A range of solar radiation management (SRM) techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air pollution. In conclusion, surface ozone and tropospheric chemistry would likely be affected by SRM, but the overall effect is strongly dependent on the SRM scheme. Due to the health and economic impacts of surface ozone, all these impacts should be taken into account in evaluations of possible consequences of SRM.

Thermal conductivity of austenitic stainless steel, SRM 735, from 5 to 280 K

NASA Technical Reports Server (NTRS)

Hust, J. G.; Sparks, L. L.

1972-01-01

Thermal conductivity and electrical resistivity measurements were conducted on two lots of an austenitic stainless steel. Electrical resistivity measurements were performed on the second lot, both before and after the material was hot-swaged and reannealed to a size 1/10 the original diameter. These measurements indicate that this steel can be swaged and reannealed without an appreciable change in thermal conductivity. Electrical resistivity measurements as well as direct thermal conductivity measurements on several specimens from both lots indicate a material variability in these lots of less than 1% in thermal conductivity.

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

Song, Ehwang; Gao, Yuqian; Wu, Chaochao

Here, mass spectrometry (MS) based targeted proteomic methods such as selected reaction monitoring (SRM) are becoming the method of choice for preclinical verification of candidate protein biomarkers. The Clinical Proteomic Tumor Analysis Consortium (CPTAC) of the National Cancer Institute has investigated the standardization and analytical validation of the SRM assays and demonstrated robust analytical performance on different instruments across different laboratories. An Assay Portal has also been established by CPTAC to provide the research community a resource consisting of large set of targeted MS-based assays, and a depository to share assays publicly, providing that assays meet the guidelines proposed bymore » CPTAC. Herein, we report 98 SRM assays covering 70 candidate protein biomarkers previously reported as associated with ovarian cancer that have been thoroughly characterized according to the CPTAC Assay Characterization Guidance Document. The experiments, methods and results for characterizing these SRM assays for their MS response, repeatability, selectivity, stability, and reproducible detection of endogenous analytes are described in detail.« less

Ecological effects and environmental fate of solid rocket exhaust

NASA Technical Reports Server (NTRS)

Nimmo, B.; Stout, I. J.; Mickus, J.; Vickers, D.; Madsen, B.

1974-01-01

Specific target processes were classified as to the chemical, chemical-physical, and biological reactions and toxic effects of solid rocket emissions within selected ecosystems at Kennedy Space Center. Exposure of Citris seedlings, English peas, and bush beans to SRM exhaust under laboratory conditions demonstrated reduced growth rates, but at very high concentrations. Field studies of natural plant populations in three diverse ecosystems failed to reveal any structural damage at the concentration levels tested. Background information on elemental composition of selected woody plants from two terrestrial ecosystems is reported. LD sub 50 for a native mouse (peromysous gossypinus) exposed to SRM exhaust was determined to be 50 ppm/g body weight. Results strongly indicate that other components of the SRM exhaust act synergically to enhance the toxic effects of HCl gas when inhaled. A brief summary is given regarding the work on SRM exhaust and its possible impact on hatchability of incubating bird eggs.

Design of C18 Organic Phases with Multiple Embedded Polar Groups for Ultraversatile Applications with Ultrahigh Selectivity.

PubMed

Mallik, Abul K; Qiu, Hongdeng; Oishi, Tomohiro; Kuwahara, Yutaka; Takafuji, Makoto; Ihara, Hirotaka

2015-07-07

For the first time, we synthesized multiple embedded polar groups (EPGs) containing linear C18 organic phases. The new materials were characterized by elemental analysis, IR spectroscopy, (1)H NMR, diffuse reflectance infrared Fourier transform (DRIFT), solid-state (13)C cross-polarization magic angle spinning (CP/MAS) NMR, suspended-state (1)H NMR, and differential scanning calorimetry (DSC). (29)Si CP/MAS NMR was carried out to investigate the degree of cross-linking of the silane and silane functionality of the modified silica. Solid-state (13)C CP/MAS NMR and suspended-state (1)H NMR spectroscopy indicated a higher alkyl chain order for the phase containing four EPGs than for the phase with three EPGs. To correlate the NMR results with temperature-dependent chromatographic studies, standard reference materials (SRM 869b and SRM 1647e), a column selectivity test mixture for liquid chromatography was employed. A single EPG containing the C18 phase was also prepared in a similar manner to be used as a reference column especially for the separation of basic and polar compounds in reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC), respectively. Detailed chromatographic characterization of the new phases was performed in terms of their surface coverage, hydrophobic selectivity, shape selectivity, hydrogen bonding capacity, and ion-exchange capacity at pH 2.7 and 7.6 for RPLC as well as their hydrophilicity, the selectivity for hydrophilic-hydrophobic substituents, the selectivity for the region and configurational differences in hydrophilic substituents, the evaluation of electrostatic interactions, and the evaluation of the acidic-basic nature for HILIC-mode separation. Furthermore, peak shapes for the basic analytes propranolol and amitriptyline were studied as a function of the number of EPGs on the C18 phases in the RPLC. The chromatographic performance of multiple EPGs containing C18 HILIC phases is illustrated by the separation of sulfa drugs, β-blockers, xanthines, nucleic acid bases, nucleosides, and water-soluble vitamins. Both of the phases showed the best performance for the separation of shape-constrained isomers, nonpolar, polar, and basic compounds in RPLC- and HILIC-mode separation of sulfa drugs, and other polar and basic analytes compared to the conventional alkyl phases with and without embedded polar groups and HILIC phases. Surprisingly, one phase would be able to serve the performance of three different types of phases with very high selectivity, and we named this phase the "smart phase". Versatile applications with a single column will reduce the column purchasing cost for the analyst as well as achieve high separation, which is challenging with the commercially available columns.

Spatial Release From Masking in 2-Year-Olds With Normal Hearing and With Bilateral Cochlear Implants

PubMed Central

Hess, Christi L.; Misurelli, Sara M.; Litovsky, Ruth Y.

2018-01-01

This study evaluated spatial release from masking (SRM) in 2- to 3-year-old children who are deaf and were implanted with bilateral cochlear implants (BiCIs), and in age-matched normal-hearing (NH) toddlers. Here, we examined whether early activation of bilateral hearing has the potential to promote SRM that is similar to age-matched NH children. Listeners were 13 NH toddlers and 13 toddlers with BiCIs, ages 27 to 36 months. Speech reception thresholds (SRTs) were measured for target speech in front (0°) and for competitors that were either Colocated in front (0°) or Separated toward the right (+90°). SRM was computed as the difference between SRTs in the front versus in the asymmetrical condition. Results show that SRTs were higher in the BiCI than NH group in all conditions. Both groups had higher SRTs in the Colocated and Separated conditions compared with Quiet, indicating masking. SRM was significant only in the NH group. In the BiCI group, the group effect of SRM was not significant, likely limited by the small sample size; however, all but two children had SRM values within the NH range. This work shows that to some extent, the ability to use spatial cues for source segregation develops by age 2 to 3 in NH children and is attainable in most of the children in the BiCI group. There is potential for the paradigm used here to be used in clinical settings to evaluate outcomes of bilateral hearing in very young children. PMID:29761735

Self-referenced memory, social cognition, and symptom presentation in autism.

PubMed

Henderson, Heather A; Zahka, Nicole E; Kojkowski, Nicole M; Inge, Anne P; Schwartz, Caley B; Hileman, Camilla M; Coman, Drew C; Mundy, Peter C

2009-07-01

We examined performance on a self-referenced memory (SRM) task for higher-functioning children with autism (HFA) and a matched comparison group. SRM performance was examined in relation to symptom severity and social cognitive tests of mentalizing. Sixty-two children (31 HFA, 31 comparison; 8-16 years) completed a SRM task in which they read a list of words and decided whether the word described something about them, something about Harry Potter, or contained a certain number of letters. They then identified words that were familiar from a longer list. Dependent measures were memory performance (d') in each of the three encoding conditions as well as a self-memory bias score (d' self-d' other). Children completed The Strange Stories Task and The Children's Eyes Test as measures of social cognition. Parents completed the SCQ and ASSQ as measures of symptom severity. Children in the comparison sample showed the standard SRM effect in which they recognized significantly more self-referenced words relative to words in the other-referenced and letter conditions. In contrast, HFA children showed comparable rates of recognition for self- and other-referenced words. For all children, SRM performance improved with age and enhanced SRM performance was related to lower levels of social problems. These associations were not accounted for by performance on the mentalizing tasks. Children with HFA did not show the standard enhanced processing of self- vs. other-relevant information. Individual differences in the tendency to preferentially process self-relevant information may be associated with social cognitive processes that serve to modify the expression of social symptoms in children with autism.

Measurement of the ultrasonic properties of human coronary arteries in vitro with a 50-MHz acoustic microscope.

PubMed

Machado, J C; Foster, F S; Gotlieb, A I

2002-08-01

Ultrasonic attenuation coefficient, wave propagation speed and integrated backscatter coefficient (IBC) of human coronary arteries were measured in vitro over the -6 dB frequency bandwidth (36 to 67 MHz) of a focused ultrasound transducer (50 MHz, focal distance 5.7 mm, f/number 1.7). Corrections were made for diffraction effects. Normal and diseased coronary artery sub-samples (N = 38) were obtained from 10 individuals at autopsy. The measured mean +/- SD of the wave speed (average over the entire vessel wall thickness) was 1581.04 +/- 53.88 m/s. At 50 MHz, the average attenuation coefficient was 4.99 +/- 1.33 dB/mm with a frequency dependence term of 1.55 +/- 0.18 determined over the 36- to 67-MHz frequency range. The IBC values were: 17.42 +/- 13.02 (sr.m)-1 for thickened intima, 11.35 +/- 6.54 (sr.m)-1 for fibrotic intima, 39.93 +/- 50.95 (sr.m)-1 for plaque, 4.26 +/- 2.34 (sr.m)-1 for foam cells, 5.12 +/- 5.85 (sr.m)-1 for media and 21.26 +/- 31.77 (sr.m)-1 for adventitia layers. The IBC results indicate the possibility for ultrasound characterization of human coronary artery wall tissue layer, including the situations of diseased arteries with the presence of thickened intima, fibrotic intima and plaque. The mean IBC normalized with respect to the mean IBC of the media layer seems promising for use as a parameter to differentiate a plaque or a thickened intima from a fibrotic intima.

An effective XML based name mapping mechanism within StoRM

NASA Astrophysics Data System (ADS)

Corso, E.; Forti, A.; Ghiselli, A.; Magnoni, L.; Zappi, R.

2008-07-01

In a Grid environment the naming capability allows users to refer to specific data resources in a physical storage system using a high level logical identifier. This logical identifier is typically organized in a file system like structure, a hierarchical tree of names. Storage Resource Manager (SRM) services map the logical identifier to the physical location of data evaluating a set of parameters as the desired quality of services and the VOMS attributes specified in the requests. StoRM is a SRM service developed by INFN and ICTP-EGRID to manage file and space on standard POSIX and high performing parallel and cluster file systems. An upcoming requirement in the Grid data scenario is the orthogonality of the logical name and the physical location of data, in order to refer, with the same identifier, to different copies of data archived in various storage areas with different quality of service. The mapping mechanism proposed in StoRM is based on a XML document that represents the different storage components managed by the service, the storage areas defined by the site administrator, the quality of service they provide and the Virtual Organization that want to use the storage area. An appropriate directory tree is realized in each storage component reflecting the XML schema. In this scenario StoRM is able to identify the physical location of a requested data evaluating the logical identifier and the specified attributes following the XML schema, without querying any database service. This paper presents the namespace schema defined, the different entities represented and the technical details of the StoRM implementation.

AmeriFlux US-SRM Santa Rita Mesquite

DOE Data Explorer

Scott, Russell [United States Department of Agriculture

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-SRM Santa Rita Mesquite. Site Description - Semidesert grassland encroached by mesquite (Prosopis velutina) trees. Please see Scott et al. 2009 JGR-Biogeo, 114, G04004

Impact of the Surgical Research Methodology Program on surgical residents' research profiles.

PubMed

Farrokhyar, Forough; Amin, Nalin; Dath, Deepak; Bhandari, Mohit; Kelly, Stephan; Kolkin, Ann M; Gill-Pottruff, Catherine; Skot, Martina; Reid, Susan

2014-01-01

To evaluate whether implementing the formal Surgical Research Methodology (SRM) Program in the surgical residency curriculum improved research productivity compared with the preceding informal Research Seminar Series (RSS). The SRM Program replaced the RSS in July 2009. In the SRM Program, the curriculum in Year-1 consisted of 12 teaching sessions on the principles of clinical epidemiology and biostatistics, whereas the focus in Year-2 was on the design, conduct, and presentation of a research project. The RSS consisted of 8 research methodology sessions repeated annually for 2 years along with the design, conduct, and presentation of a research project. Research productivity was measured as the number of peer-reviewed publications and the generation of studies with higher levels of evidence. Outcome measures were independently assessed by 2 authors to avoid bias. Student t test and chi-square test were used for the analysis. Frequencies, mean differences with 95% CI, and effect sizes have been reported. In this study, 81 SRM residents were compared with 126 RSS residents. The performance of the SRM residents was superior on all metrics in our evaluation. They were significantly more productive and published more articles than the RSS residents (mean difference = 1.0 [95% CI: 0.5-1.5], p < 0.001) with an effect size of 0.26. The SRM residents presented significantly more projects that were of higher levels of evidence (systematic reviews/meta-analyses, randomized controlled trials, and prospective cohorts) than the RSS residents (52.5% vs 29%, p = 0.005). In addition, the research performance improved 11.0 grades (95% CI: 8.5%-13.5%, p < 0.001) with an effect size of 0.51 in favor of the SRM Program. Although not all surgeons opt for a career as surgeon-scientist, knowledge of research methodology is crucial to appropriately apply evidence-based findings in clinical practice. The SRM Program has significantly improved the research productivity and performance of the surgical residents from all disciplines. The implementation of a similar research methodology program is highly recommended for the benefit of residents' future careers and ultimately, evidence-based patient care. Copyright © 2014 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Surrogate Reservoir Model

NASA Astrophysics Data System (ADS)

Mohaghegh, Shahab

2010-05-01

Surrogate Reservoir Model (SRM) is new solution for fast track, comprehensive reservoir analysis (solving both direct and inverse problems) using existing reservoir simulation models. SRM is defined as a replica of the full field reservoir simulation model that runs and provides accurate results in real-time (one simulation run takes only a fraction of a second). SRM mimics the capabilities of a full field model with high accuracy. Reservoir simulation is the industry standard for reservoir management. It is used in all phases of field development in the oil and gas industry. The routine of simulation studies calls for integration of static and dynamic measurements into the reservoir model. Full field reservoir simulation models have become the major source of information for analysis, prediction and decision making. Large prolific fields usually go through several versions (updates) of their model. Each new version usually is a major improvement over the previous version. The updated model includes the latest available information incorporated along with adjustments that usually are the result of single-well or multi-well history matching. As the number of reservoir layers (thickness of the formations) increases, the number of cells representing the model approaches several millions. As the reservoir models grow in size, so does the time that is required for each run. Schemes such as grid computing and parallel processing helps to a certain degree but do not provide the required speed for tasks such as: field development strategies using comprehensive reservoir analysis, solving the inverse problem for injection/production optimization, quantifying uncertainties associated with the geological model and real-time optimization and decision making. These types of analyses require hundreds or thousands of runs. Furthermore, with the new push for smart fields in the oil/gas industry that is a natural growth of smart completion and smart wells, the need for real time reservoir modeling becomes more pronounced. SRM is developed using the state of the art in neural computing and fuzzy pattern recognition to address the ever growing need in the oil and gas industry to perform accurate, but high speed simulation and modeling. Unlike conventional geo-statistical approaches (response surfaces, proxy models …) that require hundreds of simulation runs for development, SRM is developed only with a few (from 10 to 30 runs) simulation runs. SRM can be developed regularly (as new versions of the full field model become available) off-line and can be put online for real-time processing to guide important decisions. SRM has proven its value in the field. An SRM was developed for a giant oil field in the Middle East. The model included about one million grid blocks with more than 165 horizontal wells and took ten hours for a single run on 12 parallel CPUs. Using only 10 simulation runs, an SRM was developed that was able to accurately mimic the behavior of the reservoir simulation model. Performing a comprehensive reservoir analysis that included making millions of SRM runs, wells in the field were divided into five clusters. It was predicted that wells in cluster one & two are best candidates for rate relaxation with minimal, long term water production while wells in clusters four and five are susceptive to high water cuts. Two and a half years and 20 wells later, rate relaxation results from the field proved that all the predictions made by the SRM analysis were correct. While incremental oil production increased in all wells (wells in clusters 1 produced the most followed by wells in cluster 2, 3 …) the percent change in average monthly water cut for wells in each cluster clearly demonstrated the analytic power of SRM. As it was correctly predicted, wells in clusters 1 and 2 actually experience a reduction in water cut while a substantial increase in water cut was observed in wells classified into clusters 4 and 5. Performing these analyses would have been impossible using the original full field simulation model.

Standardizing CT lung density measure across scanner manufacturers.

PubMed

Chen-Mayer, Huaiyu Heather; Fuld, Matthew K; Hoppel, Bernice; Judy, Philip F; Sieren, Jered P; Guo, Junfeng; Lynch, David A; Possolo, Antonio; Fain, Sean B

2017-03-01

Computed Tomography (CT) imaging of the lung, reported in Hounsfield Units (HU), can be parameterized as a quantitative image biomarker for the diagnosis and monitoring of lung density changes due to emphysema, a type of chronic obstructive pulmonary disease (COPD). CT lung density metrics are global measurements based on lung CT number histograms, and are typically a quantity specifying either the percentage of voxels with CT numbers below a threshold, or a single CT number below which a fixed relative lung volume, nth percentile, falls. To reduce variability in the density metrics specified by CT attenuation, the Quantitative Imaging Biomarkers Alliance (QIBA) Lung Density Committee has organized efforts to conduct phantom studies in a variety of scanner models to establish a baseline for assessing the variations in patient studies that can be attributed to scanner calibration and measurement uncertainty. Data were obtained from a phantom study on CT scanners from four manufacturers with several protocols at various tube potential voltage (kVp) and exposure settings. Free from biological variation, these phantom studies provide an assessment of the accuracy and precision of the density metrics across platforms solely due to machine calibration and uncertainty of the reference materials. The phantom used in this study has three foam density references in the lung density region, which, after calibration against a suite of Standard Reference Materials (SRM) foams with certified physical density, establishes a HU-electron density relationship for each machine-protocol. We devised a 5-step calibration procedure combined with a simplified physical model that enabled the standardization of the CT numbers reported across a total of 22 scanner-protocol settings to a single energy (chosen at 80 keV). A standard deviation was calculated for overall CT numbers for each density, as well as by scanner and other variables, as a measure of the variability, before and after the standardization. In addition, a linear mixed-effects model was used to assess the heterogeneity across scanners, and the 95% confidence interval of the mean CT number was evaluated before and after the standardization. We show that after applying the standardization procedures to the phantom data, the instrumental reproducibility of the CT density measurement of the reference foams improved by more than 65%, as measured by the standard deviation of the overall mean CT number. Using the lung foam that did not participate in the calibration as a test case, a mixed effects model analysis shows that the 95% confidence intervals are [-862.0 HU, -851.3 HU] before standardization, and [-859.0 HU, -853.7 HU] after standardization to 80 keV. This is in general agreement with the expected CT number value at 80 keV of -855.9 HU with 95% CI of [-857.4 HU, -854.5 HU] based on the calibration and the uncertainty in the SRM certified density. This study provides a quantitative assessment of the variations expected in CT lung density measures attributed to non-biological sources such as scanner calibration and scanner x-ray spectrum and filtration. By removing scanner-protocol dependence from the measured CT numbers, higher accuracy and reproducibility of quantitative CT measures were attainable. The standardization procedures developed in study may be explored for possible application in CT lung density clinical data. © 2017 American Association of Physicists in Medicine.

Antibody-free PRISM-SRM for multiplexed protein quantification: Is this the new competition for immunoassays in bioanalysis?

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

Shi, Tujin; Qian, Weijun

2013-02-01

Highly sensitive technologies for multiplexed quantification of a large number of candidate proteins will play an increasingly important role in clinical biomarker discovery, systems biology, and general biomedical research. Herein we introduce the new PRISM-SRM technology, which represents a highly sensitive multiplexed quantification technology capable of simultaneous quantification of many low-abundance proteins without the need of affinity reagents. The versatility of antibody-free PRISM-SRM for quantifying various types of targets including protein isoforms, protein modifications, metabolites, and others, thus offering new competition with immunoassays.

Optical model with multiple band couplings using soft rotator structure

NASA Astrophysics Data System (ADS)

Martyanov, Dmitry; Soukhovitskii, Efrem; Capote, Roberto; Quesada, Jose Manuel; Chiba, Satoshi

2017-09-01

A new dispersive coupled-channel optical model (DCCOM) is derived that describes nucleon scattering on 238U and 232Th targets using a soft-rotator-model (SRM) description of the collective levels of the target nucleus. SRM Hamiltonian parameters are adjusted to the observed collective levels of the target nucleus. SRM nuclear wave functions (mixed in K quantum number) have been used to calculate coupling matrix elements of the generalized optical model. Five rotational bands are coupled: the ground-state band, β-, γ-, non-axial- bands, and a negative parity band. Such coupling scheme includes almost all levels below 1.2 MeV of excitation energy of targets. The "effective" deformations that define inter-band couplings are derived from SRM Hamiltonian parameters. Conservation of nuclear volume is enforced by introducing a monopolar deformed potential leading to additional couplings between rotational bands. The present DCCOM describes the total cross section differences between 238U and 232Th targets within experimental uncertainty from 50 keV up to 200 MeV of neutron incident energy. SRM couplings and volume conservation allow a precise calculation of the compound-nucleus (CN) formation cross sections, which is significantly different from the one calculated with rigid-rotor potentials with any number of coupled levels.

High-Throughput Screening To Identify Potent and Specific Inhibitors of Microbial Sulfate Reduction.

PubMed

Carlson, Hans K; Mullan, Mark R; Mosqueda, Lorraine A; Chen, Steven; Arkin, Michelle R; Coates, John D

2017-06-20

The selective perturbation of complex microbial ecosystems to predictably influence outcomes in engineered and industrial environments remains a grand challenge for geomicrobiology. In some industrial ecosystems, such as oil reservoirs, sulfate reducing microorganisms (SRM) produce hydrogen sulfide which is toxic, explosive, and corrosive. Despite the economic cost of sulfidogenesis, there has been minimal exploration of the chemical space of possible inhibitory compounds, and very little work has quantitatively assessed the selectivity of putative souring treatments. We have developed a high-throughput screening strategy to identify potent and selective inhibitors of SRM, quantitatively ranked the selectivity and potency of hundreds of compounds and identified previously unrecognized SRM selective inhibitors and synergistic interactions between inhibitors. Zinc pyrithione is the most potent inhibitor of sulfidogenesis that we identified, and is several orders of magnitude more potent than commonly used industrial biocides. Both zinc and copper pyrithione are also moderately selective against SRM. The high-throughput (HT) approach we present can be readily adapted to target SRM in diverse environments and similar strategies could be used to quantify the potency and selectivity of inhibitors of a variety of microbial metabolisms. Our findings and approach are relevant to efforts to engineer environmental ecosystems and also to understand the role of natural gradients in shaping microbial niche space.

Using Data Independent Acquisition (DIA) to Model High-responding Peptides for Targeted Proteomics Experiments*

PubMed Central

Searle, Brian C.; Egertson, Jarrett D.; Bollinger, James G.; Stergachis, Andrew B.; MacCoss, Michael J.

2015-01-01

Targeted mass spectrometry is an essential tool for detecting quantitative changes in low abundant proteins throughout the proteome. Although selected reaction monitoring (SRM) is the preferred method for quantifying peptides in complex samples, the process of designing SRM assays is laborious. Peptides have widely varying signal responses dictated by sequence-specific physiochemical properties; one major challenge is in selecting representative peptides to target as a proxy for protein abundance. Here we present PREGO, a software tool that predicts high-responding peptides for SRM experiments. PREGO predicts peptide responses with an artificial neural network trained using 11 minimally redundant, maximally relevant properties. Crucial to its success, PREGO is trained using fragment ion intensities of equimolar synthetic peptides extracted from data independent acquisition experiments. Because of similarities in instrumentation and the nature of data collection, relative peptide responses from data independent acquisition experiments are a suitable substitute for SRM experiments because they both make quantitative measurements from integrated fragment ion chromatograms. Using an SRM experiment containing 12,973 peptides from 724 synthetic proteins, PREGO exhibits a 40–85% improvement over previously published approaches at selecting high-responding peptides. These results also represent a dramatic improvement over the rules-based peptide selection approaches commonly used in the literature. PMID:26100116

Expediting SRM assay development for large-scale targeted proteomics experiments

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

Wu, Chaochao; Shi, Tujin; Brown, Joseph N.

2014-08-22

Due to their high sensitivity and specificity, targeted proteomics measurements, e.g. selected reaction monitoring (SRM), are becoming increasingly popular for biological and translational applications. Selection of optimal transitions and optimization of collision energy (CE) are important assay development steps for achieving sensitive detection and accurate quantification; however, these steps can be labor-intensive, especially for large-scale applications. Herein, we explored several options for accelerating SRM assay development evaluated in the context of a relatively large set of 215 synthetic peptide targets. We first showed that HCD fragmentation is very similar to CID in triple quadrupole (QQQ) instrumentation, and by selection ofmore » top six y fragment ions from HCD spectra, >86% of top transitions optimized from direct infusion on QQQ instrument are covered. We also demonstrated that the CE calculated by existing prediction tools was less accurate for +3 precursors, and a significant increase in intensity for transitions could be obtained using a new CE prediction equation constructed from the present experimental data. Overall, our study illustrates the feasibility of expediting the development of larger numbers of high-sensitivity SRM assays through automation of transitions selection and accurate prediction of optimal CE to improve both SRM throughput and measurement quality.« less

Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality

NASA Astrophysics Data System (ADS)

Nowack, Peer Johannes; Abraham, Nathan Luke; Braesicke, Peter; Pyle, John Adrian

2016-03-01

Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere-ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both stratospheric and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

Bridging the Gap: From Model Surfaces to Nanoparticle Analogs for Selective Oxidation and Steam Reforming of Methanol and Selective Hydrogenation Catalysis

NASA Astrophysics Data System (ADS)

Boucher, Matthew B.

Most industrial catalysts are very complex, comprising of non-uniform materials with varying structures, impurities, and interaction between the active metal and supporting substrate. A large portion of the ongoing research in heterogeneous catalysis focuses on understanding structure-function relationships in catalytic materials. In parallel, there is a large area of surface science research focused on studying model catalytic systems for which structural parameters can be tuned and measured with high precision. It is commonly argued, however, that these systems are oversimplified, and that observations made in model systems do not translate to robust catalysts operating in practical environments; this discontinuity is often referred to as a "gap." The focus of this thesis is to explore the mutual benefits of surface science and catalysis, or "bridge the gap," by studying two catalytic systems in both ultra-high vacuum (UHV) and near ambient-environments. The first reaction is the catalytic steam reforming of methanol (SRM) to hydrogen and carbon dioxide. The SRM reaction is a promising route for on-demand hydrogen production. For this catalytic system, the central hypothesis in this thesis is that a balance between redox capability and weak binding of reaction intermediates is necessary for high SRM activity and selectivity to carbon dioxide. As such, a new catalyst for the SRM reaction is developed which incorporates very small amounts of gold (<1 atomic %) supported on zinc oxide nanoparticles with controlled crystal structures. The performance of these catalysts was studied in a fixed-bed micro-reactor system at ambient pressures, and their structure was characterized by high-resolution microscopic and spectroscopic techniques. Pre-existing oxygen defects in zinc oxide {0001} surfaces, and those created by a perturbation of the defect equilibrium by addition of gold, provide an anchoring site for highly dispersed gold species. By utilizing shape control of zinc oxide supports, it is found that highly dispersed gold, capable of low-temperature redox behavior is most prominent on zinc oxide {0001} surfaces and leads to high SRM activity and selectivity to carbon dioxide. Like other Group IB metal catalysts the SRM over gold-zinc oxide proceeds through the formation and weak binding of formaldehyde, and subsequent coupling with methoxy to produce methyl formate. Mechanistic clarification of this point was achieved by studying the interaction methanol-water mixtures with model catalyst surfaces. Model catalysts were studied in a UHV chamber where the base pressure was maintained at 10-10 mbar. High resolutions surface science techniques show that hydrogen-bonded networks of water are capable of deprotonating methanol to methoxy on low index surfaces in the absence of atomic oxygen. These UHV studies show that adsorbates, other than oxygen, are capable of activating methanol on Group IB metal surfaces. The second reaction involves the selective hydrogenation of alkynes to alkenes. Selective hydrogenations of carbon-carbon multiple bonds are important for a wide range of industrial processes. The governing hypothesis for this reaction system is that cooperation between a minority metal with a low barrier for hydrogen dissociation, and a less-reactive host metal capable of hydrogen uptake via spillover will lead to high alkene selectivity. A strategy for the preparation of such a catalyst is developed using model catalyst studied in a UHV chamber. The model catalyst features isolated palladium atoms in a copper(111) surface, termed single atom alloy (SAA). Individual, isolated palladium atoms act as sites for hydrogen uptake, dissociation, and spillover onto an otherwise inert copper(111) host. Weak binding offered by copper provides a surface where selective hydrogenation reactions can take place. Palladium-copper SAA model catalysts are highly selective to the partial hydrogenation of acetylene, whereas surfaces containing larger palladium ensembles facilitate complete hydrogenation and decomposition. Nanoparticle analogs of palladium-copper SAAs were prepared to investigate the feasibility of this strategy for practical application. Very small amounts of palladium (<0.2 atomic %) on the surface of copper nanoparticles are highly active and selective catalysts for the partial hydrogenation of phenylacetylene to styrene. The performance of these catalysts was studied in a liquid-phase, stirred-tank batch reactor under a hydrogen head pressure of approximately 7 bar. Palladium alloyed into the surface of otherwise inactive copper nanoparticles shows a marked improvement in selectivity when compared to monometallic palladium catalysts with the same metal loading. This effect is attributed hydrogen spillover onto the copper surface. In summary, the development of new, highly active and selective catalysts for the methanol steam reforming reaction and for the partial hydrogenation of alkynes to alkenes was accomplished by the use of state-of-the-art techniques in both surface science and heterogeneous catalysis. The implications of this work can be extended to a wide variety of catalytic systems.

Paleomagnetism Onboard the IODP Research Vessel JOIDES Resolution: Recent Advances, Best Practices, and Pitfalls

NASA Astrophysics Data System (ADS)

Acton, G. D.; Morris, A.; Musgrave, R. J.; Zhao, X., , prof; Clement, B. M.; Evans, H. F.; Hastedt, M.; Houpt, D.; Mills, B.; Novak, B.; Petronotis, K. E.

2017-12-01

One of the largest openly available paleomagnetism databases is derived from paleomagnetic data acquired continuously along drill cores collected by the International Ocean Discovery Program (IODP) and its predecessors. The bulk of data are magnetic remanences measured using superconducting rock magnetometers (SRMs) with automated track systems and in-line alternating field (AF) demagnetization units produced by 2G Enterprises. Our goal in this study is to (1) report on the new SRM that was installed onboard the JOIDES Resolution in December 2016 prior to the start of IODP Expedition 366, (2) consider best practices that may aid shipboard scientists in collecting high quality data, and (3) discuss common pitfalls associated with using an SRM in the shipboard environment to measure a diverse range of lithologies collected in metal core barrels that pass through a relatively strongly magnetized drill string. From a series of tests conducted on the new SRM during a June 11-13, 2017 port call, our main conclusion was that the new magnetometer is functioning as designed. While overall its capabilities are comparable to the previous magnetometer, the new SRM does have several significant advances, including better flux counting, which allows more strongly magnetized rocks to be measured accurately. It also performs AF demagnetizations at high fields (up to 80 mT) without imparting spurious anhysteretic magnetizations, which was a common problem in the old SRM. A worrisome observation, and one that has been made in many shore-based labs, is that devices that emit radio-frequency electromagnetic waves, like actively transmitting cell phones, interfere significantly with SRM measurements. This pitfall will likely have to be addressed on all forthcoming cruises unless better electromagnetic shielding for the SQUID sensors can be found.

Self-Referenced Memory, Social Cognition, and Symptom Presentation in Autism

PubMed Central

Henderson, Heather A.; Zahka, Nicole E.; Kojkowski, Nicole M.; Inge, Anne P.; Schwartz, Caley B.; Hileman, Camilla M.; Coman, Drew C.; Mundy, Peter C.

2009-01-01

Background We examined performance on a self-referenced memory (SRM) task for higher functioning children with autism (HFA) and a matched comparison group. SRM performance was examined in relation to symptom severity and social cognitive tests of mentalizing. Method Sixty-two children (31 HFA, 31 comparison; 8–16 years) completed a SRM task in which they read a list of words and decided whether the word described something about them, something about Harry Potter, or contained a certain number of letters. They then identified words that were familiar from a longer list. Dependent measures were memory performance (d′) in each of the three encoding conditions as well as a self-memory bias score (d′ self-d′ other). Children completed The Strange Stories Task and The Children’s Eyes Test as measures of social cognition. Parents completed the SCQ and ASSQ as measures of symptom severity. Results Children in the comparison sample showed the standard SRM effect in which they recognized significantly more self-referenced words relative to words in the other-referenced and letter conditions. In contrast, HFA children showed comparable rates of recognition for self- and other-referenced words. For all children, SRM performance improved with age and enhanced SRM performance was related to lower levels of social problems. These associations were not accounted for by performance on the mentalizing tasks. Conclusions Children with HFA did not show the standard enhanced processing of self- vs. other-relevant information. Individual differences in the tendency to preferentially process self-relevant information may be associated with social cognitive processes that serve to modify the expression of social symptoms in children with autism. PMID:19298471

Analysis of Serum Total and Free PSA Using Immunoaffinity Depletion Coupled to SRM: Correlation with Clinical Immunoassay Tests

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

Liu, Tao; Hossain, Mahmud; Schepmoes, Athena A.

2012-08-03

Sandwich immunoassay is the standard technique used in clinical labs for quantifying protein biomarkers for disease detection, monitoring and therapeutic intervention. Albeit highly sensitive, the development of a specific immunoassay is rather time-consuming and associated with extremely high cost due to the requirement for paired immunoaffinity reagents of high specificity. Recently, mass spectrometry-based methods, specifically selected reaction monitoring mass spectrometry (SRM-MS), have been increasingly applied to measure low abundance biomarker candidates in tissue and biofluids, owing to high sensitivity and specificity, simplicity of assay configuration, and great multiplexing capability. In this study, we report for the first time the developmentmore » of immunoaffinity depletion-based workflows and SRM-MS assays that enable sensitive and accurate quantification of total and free prostate-specific antigen (PSA) in serum without the requirement for specific PSA antibodies. With stable isotope dilution and external calibration, low ng/mL level detection of both total and free PSA was consistently achieved in both PSA-spiked female serum samples and actual patient serum samples. Moreover, comparison of the results obtained when SRM PSA assays and conventional immunoassays were applied to the same samples showed very good correlation (R2 values ranging from 0.90 to 0.99) in several independent clinical serum sample sets, including a set of 33 samples assayed in a blinded test. These results demonstrate that the workflows and SRM assays developed here provide an attractive alternative for reliably measuring total and free PSA in human blood. Furthermore, simultaneous measurement of free and total PSA and many other biomarkers can be performed in a single analysis using high-resolution liquid chromatographic separation coupled with SRM-MS.« less

An Analysis of the Orbital Distribution of Solid Rocket Motor Slag

NASA Technical Reports Server (NTRS)

Horstman, Matthew F.; Mulrooney, Mark

2007-01-01

The contribution made by orbiting solid rocket motors (SRMs) to the orbital debris environment is both potentially significant and insufficiently studied. A combination of rocket motor design and the mechanisms of the combustion process can lead to the emission of sufficiently large and numerous by-products to warrant assessment of their contribution to the orbital debris environment. These particles are formed during SRM tail-off, or the termination of burn, by the rapid expansion, dissemination, and solidification of the molten Al2O3 slag pool accumulated during the main burn phase of SRMs utilizing immersion-type nozzles. Though the usage of SRMs is low compared to the usage of liquid fueled motors, the propensity of SRMs to generate particles in the 100 m and larger size regime has caused concern regarding their contributing to the debris environment. Particle sizes as large as 1 cm have been witnessed in ground tests conducted under vacuum conditions and comparable sizes have been estimated via ground-based telescopic and in-situ observations of sub-orbital SRM tail-off events. Using sub-orbital and post recovery observations, a simplistic number-size-velocity distribution of slag from on-orbit SRM firings was postulated. In this paper we have developed more elaborate distributions and emission scenarios and modeled the resultant orbital population and its time evolution by incorporating a historical database of SRM launches, propellant masses, and likely location and time of particulate deposition. From this analysis a more comprehensive understanding has been obtained of the role of SRM ejecta in the orbital debris environment, indicating that SRM slag is a significant component of the current and future population.

Validity and reliability of the PowerTap mobile cycling powermeter when compared with the SRM Device.

PubMed

Bertucci, W; Duc, S; Villerius, V; Pernin, J N; Grappe, F

2005-12-01

The SRM power measuring crank system is nowadays a popular device for cycling power output (PO) measurements in the field and in laboratories. The PowerTap (CycleOps, Madison, USA) is a more recent and less well-known device that allows mobile PO measurements of cycling via the rear wheel hub. The aim of this study is to test the validity and reliability of the PowerTap by comparing it with the most accurate (i.e. the scientific model) of the SRM system. The validity of the PowerTap is tested during i) sub-maximal incremental intensities (ranging from 100 to 420 W) on a treadmill with different pedalling cadences (45 to 120 rpm) and cycling positions (standing and seated) on different grades, ii) a continuous sub-maximal intensity lasting 30 min, iii) a maximal intensity (8-s sprint), and iiii) real road cycling. The reliability is assessed by repeating ten times the sub-maximal incremental and continuous tests. The results show a good validity of the PowerTap during sub-maximal intensities between 100 and 450 W (mean PO difference -1.2 +/- 1.3 %) when it is compared to the scientific SRM model, but less validity for the maximal PO during sprint exercise, where the validity appears to depend on the gear ratio. The reliability of the PowerTap during the sub-maximal intensities is similar to the scientific SRM model (the coefficient of variation is respectively 0.9 to 2.9 % and 0.7 to 2.1 % for PowerTap and SRM). The PowerTap must be considered as a suitable device for PO measurements during sub-maximal real road cycling and in sub-maximal laboratory tests.

Influence of La content on magnetic properties of Cu doped M-type strontium hexaferrite: Structural, magnetic, and Mossbauer spectroscopy study

NASA Astrophysics Data System (ADS)

Ghimire, M.; Yoon, S.; Wang, L.; Neupane, D.; Alam, J.; Mishra, S. R.

2018-05-01

The present study investigates the influence of Cu2+ and La3+-Cu2+ doping on the magnetic properties of Sr1-xLaxFe12-xCuxO19 (x = 0.0-0.5) hexaferrite (SrM) compounds. The samples were prepared via facile autocombustion technique followed by sintering. X-ray powder diffraction patterns show the formation of the pure phase of M-type hexaferrite for all x. Invariance in lattice parameters was observed with only Cu2+ substitution while lattice contraction along c-axis was observed with co-doping La3+-Cu2+ in SrM. The magnetic property of these compounds is explained based on Cu2+ occupancy in the absence and presence of La3+ in SrM magnetoplumbite structure. The Cu2+ doped SrFe12-xCuxO19 sample showed a monotonic decrease in Ms value while La3+-Cu2+ showed a noticeable increase in Ms value with x. Furthermore, while coercivity of Cu2+ doped SrM reduced with x, the coercivity of La3+-Cu2+ doped SrM showed a marked 12% increase in coercivity at x = 0.1 (Hc = 4391 Oe) from that of x = 0.0 (3918 Oe). Interestingly, Cu2+ doped SrM displayed invariance in Tc ∼ 458.6 °C with x, while La3+-Cu2+ doping reduced Tc by 5% from its x = 0 (Tc = 451.9 °C) to 429.6 °C. The room temperature Mossbauer spectral analysis confirmed a Cu2+ preference for the 12k site and its occupancy is observed to be influenced by the presence of La3+ ion at the Sr2+ site.

Shortening of the bovine tongue according to regulation (EC) 999/2001 is not complying with the current legal definition of specified risk material - a macroscopical and histological preliminary study.

PubMed

Kühne, M; Klein, G; Gasse, H

2005-03-01

The full elimination of all specified risk material (SRM) in food of animal origin is crucial for consumer protection and is of high priority in inner EU trade. Among other tissues, the tonsils of cattle are considered as SRM. The aim of this study was to evaluate whether the 'cut at the back of the tongue just before the tongue bones' required by EC regulation is sufficient to remove tonsils and lymphatic tissue completely. Eight skulls from cattle were collected for the simulation of a vertical cut according to the EC regulation and the detection of the target at the back of the tongue. Further, specimens of the lingual mucosa were cut out from two tongues and examined microscopically. The most caudal of these specimens was from the macroscopically visible part of the lingual tonsil. The most rostral specimen contained the most caudal Papilla vallata. Simulation of the obligatory ventro-dorsal cut yielded hits at varying locations on the dorsal surface of the tongue, sometimes including tissue of the lingual tonsil. Histological examination of the lingual mucosa gave clear evidence that lymphatic tissue resembling the tissue of a tonsil in terms of its histological organization and infiltration of the mucosal epithelium could even be found in areas with no macroscopically visible lingual tonsils.

Development of a solid propellant viscoelastic dynamic model

NASA Technical Reports Server (NTRS)

Hufferd, W. L.; Fitzgerald, J. E.

1976-01-01

The results of a one year study to develop a dynamic response model for the Space Shuttle Solid Rocket Motor (SRM) propellant are presented. An extensive literature survey was conducted, from which it was concluded that the only significant variables affecting the dynamic response of the SRM propellant are temperature and frequency. Based on this study, and experimental data on propellants related to the SRM propellant, a dynamic constitutive model was developed in the form of a simple power law with temperature incorporated in the form of a modified power law. A computer program was generated which performs a least-squares curve-fit of laboratory data to determine the model parameters and it calculates dynamic moduli at any desired temperature and frequency. Additional studies investigated dynamic scaling laws and the extent of coupling between the SRM propellant and motor cases. It was found, in agreement with other investigations, that the propellant provides all of the mass and damping characteristics whereas the case provides all of the stiffness.

Ethics as an Integral Component of Geoengineering Analysis

NASA Astrophysics Data System (ADS)

Haqq-Misra, J.; Tuana, N.; Keller, K.; Sriver, R. L.; Svoboda, T.; Tonkonojenkov, R.; Irvine, P. J.

2011-12-01

Concerns about the risks of unmitigated greenhouse gas emissions are growing. At the same time, confidence is declining that international policy agreements will succeed in considerably lowering anthropogenic greenhouse gas emissions. Perhaps as a result, various geoengineering solutions are gaining attention and credibility as a way to manage climate change. Serious consideration is currently being given to proposals to cool the planet through solar-radiation management (SRM). Here we analyze how the unique and nontrivial risks of geoengineering strategies pose fundamental questions at the interface between science and ethics. We define key open questions to analyze SRM geoengineering proposals, which include whether SRM can be tested, how quickly learning could occur, normative decisions embedded in how different climate trajectories are valued, and justice issues regarding distribution of the harms and benefits of geoengineering. To ensure that ethical analyses are coupled with scientific analyses of this form of geoengineering, we advocate that funding agencies recognize the essential nature of this coupled research by establishing an Ethical, Legal, and Social Implications (ELSI) program for SRM.

Targeted proteomic assays for quantitation of proteins identified by proteogenomic analysis of ovarian cancer

DOE PAGES

Song, Ehwang; Gao, Yuqian; Wu, Chaochao; ...

2017-07-19

Here, mass spectrometry (MS) based targeted proteomic methods such as selected reaction monitoring (SRM) are becoming the method of choice for preclinical verification of candidate protein biomarkers. The Clinical Proteomic Tumor Analysis Consortium (CPTAC) of the National Cancer Institute has investigated the standardization and analytical validation of the SRM assays and demonstrated robust analytical performance on different instruments across different laboratories. An Assay Portal has also been established by CPTAC to provide the research community a resource consisting of large set of targeted MS-based assays, and a depository to share assays publicly, providing that assays meet the guidelines proposed bymore » CPTAC. Herein, we report 98 SRM assays covering 70 candidate protein biomarkers previously reported as associated with ovarian cancer that have been thoroughly characterized according to the CPTAC Assay Characterization Guidance Document. The experiments, methods and results for characterizing these SRM assays for their MS response, repeatability, selectivity, stability, and reproducible detection of endogenous analytes are described in detail.« less

Enhanced Control of Listeria monocytogenes by Enterococcus faecium KE82, a Multiple Enterocin-Producing Strain, in Different Milk Environments.

PubMed

Vandera, Elpiniki; Lianou, Alexandra; Kakouri, Athanasia; Feng, Jinbo; Koukkou, Anna-Irini; Samelis, John

2017-01-01

Enterococcus faecium KE82, isolated from traditional Greek Graviera cheese, was identified in pure broth cultures in vitro as a multiple enterocin-producing bacterial strain possessing the structural entA, entB, and entP enterocin genes. E. faecium KE82 was further assessed for in situ antilisterial activity in raw milk (RM) and commercially thermized milk (TM; 63°C for 30 s) in the presence of the indigenous microbiota and in sterile raw milk (SRM; 121°C for 5 min) with or without the addition of two commercial starter culture (CSC) strains Streptococcus thermophilus and Lactococcus lactis . Growth of Listeria monocytogenes was completely inhibited in RM incubated at 37°C for 6 h, whereas the pathogen was significantly inactivated in RM+KE82 samples during further incubation at 18°C for 66 h. In contrast, L. monocytogenes levels increased by approximately 2 log CFU/ml in TM, but in TM+KE82 samples, pathogen growth was retarded during the first 6 h at 37°C followed by growth cessation and partial inactivation at 18°C. After 48 to 72 h, growth of L. monocytogenes in SRM+CSC samples decreased by 4 to 5 log CFU/ml compared with the SRM control, whereas additional 10-fold decreases in the pathogen were observed in SRM+CSC+KE82 samples. Reverse transcription PCR analysis of SRM+KE82 and SRM+CSC+KE82 samples confirmed that the entA and entB genes were transcribed, but entP gene transcription was not detected. All RM and SRM samples inoculated with E. faecium KE82 displayed strong in situ inhibitory activity against L. monocytogenes in well diffusion bioassays, whereas activity was weaker to undetectable in comparable or additional TM+KE82 samples; no milk sample without E. faecium KE82 had activity against L. monocytogenes . The findings of this study indicate that E. faecium KE82 is an antilisterial agent that could be used in traditional dairy foods because it concomitantly produces enterocins A and B in situ in milk.

A proposal for the international regulation of solar radiation management research

NASA Astrophysics Data System (ADS)

Morrow, D. R.; Kopp, R. E.; Lloyd, I. D.; Oppenheimer, M.

2011-12-01

The most ethically problematic experiments in geoengineering are regional or global trials of solar radiation management (SRM) technologies. Because of their potential wide-spread impacts, if trials are to be conducted, international oversight is necessary to assure they are conducted ethically. The three main questions to ask about any (constellation of) institution(s) that would oversee SRM trials are: (1) Is it conducive to good science? (2) Is it politically effective? (3) Is it politically legitimate? We sketch a proposal for an international body that would regulate SRM trials in such a way as to promote an affirmative answer to all three questions.

A new two-phase homopolar switched reluctance motor for electric vehicle applications

NASA Astrophysics Data System (ADS)

Tsai, Mi-Ching; Huang, Chien-Chin; Huang, Zheng-Yi

2003-12-01

This paper presents a novel 2-phase homopolar switched reluctance motor (SRM), whose design successfully avoids dead-zone problems that afflict low cost 1- and/or 2-phase SRMs. Unlike conventional radial-winding-radial-gap motors, the proposed SRM has an interior stator that is of the pancake type with axial winding. Such a design allows for a high slot-fill factor and is suitable for implementation as a flat pancake-shaped stator. An efficient, compact prototype was produced with TMS320F240 DSP driving control unit. Experimental results indicate that the present SRM design has the potential to be used for electric bicycles and scooters.

Solution of internal ballistic problem for SRM with grain of complex shape during main firing phase

NASA Astrophysics Data System (ADS)

Kiryushkin, A. E.; Minkov, L. L.

2017-10-01

Solid rocket motor (SRM) internal ballistics problems are related to the problems with moving boundaries. The algorithm able to solve similar problems in axisymmetric formulation on Cartesian mesh with an arbitrary order of accuracy is considered in this paper. The base of this algorithm is the ghost point extrapolation using inverse Lax-Wendroff procedure. Level set method is used as an implicit representation of the domain boundary. As an example, the internal ballistics problem for SRM with umbrella type grain was solved during the main firing phase. In addition, flow parameters distribution in the combustion chamber was obtained for different time moments.

Lunar Paleomagnetism: The Case for an Ancient Lunar Dynamo. (Invited)

NASA Astrophysics Data System (ADS)

Fuller, M.; Weiss, B. P.; Gattacceca, J.

2010-12-01

The failure of lunar samples to satisfy minimal criteria for classical paleointensity determinations has led to skepticism of the case for an ancient lunar dynamo. There are however practical and fundamental reasons why such experiments are doomed to failure in most lunar samples. In such methods, NRMs in successive blocking temperatures ranges are thermally demagnetized and replaced with partial thermoremanent magnetization (pTRMs) given in a known field (Thellier, 1938). A practical difficulty is that it is hard to heat lunar samples without altering them. A fundamental problem is that whereas pottery, for which these methods were designed, carries a primary (TRM) from its initial cooling and little secondary magnetization, lunar samples are likely to carry weak field isothermal remanent magnetization (IRM) and shock remanent magnetization (SRM) as secondary overprints. Thermal demagnetization does not isolate weak field IRM well. For example, on thermal demagnetization of the Apollo sample 14053.48 carrying a 2000nT TRM with a superposed 5mT IRM, the IRM persists to the Curie point obscuring the TRM. Fortunately, weak field IRM is removed by AF demagnetization to fields comparable to that in which it is acquired. Furthermore, Gattacceca et al. (2008) demonstrated that experimentally generated SRM from several GPa, like weak field IRM, is demagnetized by AF fields of between ~20 and 30 mT, leaving the pre-shock remanent magnetization essentially untouched. This agrees with our theoretical understanding of SRM, which at pressures below approximately the Hugoniot elastic limit (several GPa for most rocks) should essentially be a pressure remanent magnetization (e.g., Dunlop and Ozdemir, 1997). Unlike IRM, SRM in the range of a few GPa may carry recoverable lunar field records (Gattacceca et al., 2008). NRM in samples shocked to less than ~5 GPa, which is stable against AF demagnetization beyond the fields necessary to eliminate weak SRM (~20-30 mT), requires some other explanation. Such NRM carried by the small amount of single domain iron and iron nickel present in the samples can be very stable. The troctolite 76535 is an example of such a sample. It cooled over thousands of years, or longer, which is far too long for any possible transient fields associated with impacts and must carry a TRM like NRM. Note that despite predictions that even km sized craters may generate fields up to 0.1T at 1 crater radius, no unambiguous evidence for paleomagnetic recording of such fields over individual craters has materialized. There are numerous other candidate samples having experienced <~5 GPa carrying stable NRM, which have been analyzed, or are being presently investigated. The only other obvious source of a field to explain stable TRM in lunar rocks is that of surface lunar fields, but over the mare these are too weak to account for the NRM of mare basalts. In summary, recent advances in our understanding of SRM and reanalysis of lunar paleomagnetism lead us to conclude that lunar paleomagnetism is most easily explained by a lunar dynamo.

Advances in targeted proteomics and applications to biomedical research

PubMed Central

Shi, Tujin; Song, Ehwang; Nie, Song; Rodland, Karin D.; Liu, Tao; Qian, Wei-Jun; Smith, Richard D.

2016-01-01

Targeted proteomics technique has emerged as a powerful protein quantification tool in systems biology, biomedical research, and increasing for clinical applications. The most widely used targeted proteomics approach, selected reaction monitoring (SRM), also known as multiple reaction monitoring (MRM), can be used for quantification of cellular signaling networks and preclinical verification of candidate protein biomarkers. As an extension to our previous review on advances in SRM sensitivity herein we review recent advances in the method and technology for further enhancing SRM sensitivity (from 2012 to present), and highlighting its broad biomedical applications in human bodily fluids, tissue and cell lines. Furthermore, we also review two recently introduced targeted proteomics approaches, parallel reaction monitoring (PRM) and data-independent acquisition (DIA) with targeted data extraction on fast scanning high-resolution accurate-mass (HR/AM) instruments. Such HR/AM targeted quantification with monitoring all target product ions addresses SRM limitations effectively in specificity and multiplexing; whereas when compared to SRM, PRM and DIA are still in the infancy with a limited number of applications. Thus, for HR/AM targeted quantification we focus our discussion on method development, data processing and analysis, and its advantages and limitations in targeted proteomics. Finally, general perspectives on the potential of achieving both high sensitivity and high sample throughput for large-scale quantification of hundreds of target proteins are discussed. PMID:27302376

Advances in targeted proteomics and applications to biomedical research

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

Shi, Tujin; Song, Ehwang; Nie, Song

Targeted proteomics technique has emerged as a powerful protein quantification tool in systems biology, biomedical research, and increasing for clinical applications. The most widely used targeted proteomics approach, selected reaction monitoring (SRM), also known as multiple reaction monitoring (MRM), can be used for quantification of cellular signaling networks and preclinical verification of candidate protein biomarkers. As an extension to our previous review on advances in SRM sensitivity (Shi et al., Proteomics, 12, 1074–1092, 2012) herein we review recent advances in the method and technology for further enhancing SRM sensitivity (from 2012 to present), and highlighting its broad biomedical applications inmore » human bodily fluids, tissue and cell lines. Furthermore, we also review two recently introduced targeted proteomics approaches, parallel reaction monitoring (PRM) and data-independent acquisition (DIA) with targeted data extraction on fast scanning high-resolution accurate-mass (HR/AM) instruments. Such HR/AM targeted quantification with monitoring all target product ions addresses SRM limitations effectively in specificity and multiplexing; whereas when compared to SRM, PRM and DIA are still in the infancy with a limited number of applications. Thus, for HR/AM targeted quantification we focus our discussion on method development, data processing and analysis, and its advantages and limitations in targeted proteomics. Finally, general perspectives on the potential of achieving both high sensitivity and high sample throughput for large-scale quantification of hundreds of target proteins are discussed.« less

The relationship between lifestyle regularity and subjective sleep quality

NASA Technical Reports Server (NTRS)

Monk, Timothy H.; Reynolds, Charles F 3rd; Buysse, Daniel J.; DeGrazia, Jean M.; Kupfer, David J.

2003-01-01

In previous work we have developed a diary instrument-the Social Rhythm Metric (SRM), which allows the assessment of lifestyle regularity-and a questionnaire instrument--the Pittsburgh Sleep Quality Index (PSQI), which allows the assessment of subjective sleep quality. The aim of the present study was to explore the relationship between lifestyle regularity and subjective sleep quality. Lifestyle regularity was assessed by both standard (SRM-17) and shortened (SRM-5) metrics; subjective sleep quality was assessed by the PSQI. We hypothesized that high lifestyle regularity would be conducive to better sleep. Both instruments were given to a sample of 100 healthy subjects who were studied as part of a variety of different experiments spanning a 9-yr time frame. Ages ranged from 19 to 49 yr (mean age: 31.2 yr, s.d.: 7.8 yr); there were 48 women and 52 men. SRM scores were derived from a two-week diary. The hypothesis was confirmed. There was a significant (rho = -0.4, p < 0.001) correlation between SRM (both metrics) and PSQI, indicating that subjects with higher levels of lifestyle regularity reported fewer sleep problems. This relationship was also supported by a categorical analysis, where the proportion of "poor sleepers" was doubled in the "irregular types" group as compared with the "non-irregular types" group. Thus, there appears to be an association between lifestyle regularity and good sleep, though the direction of causality remains to be tested.

76 FR 22308 - Airworthiness Directives; Airbus Model A340-541 and -642 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-21

... airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct... PB201 were de-validated starting from the SRM revision issued on January 2009. The terminology ``De... ``de-validated SRM'' repairs and, if necessary, to apply the associated corrective actions [repair...

Students' Motivation to Learn in Middle School--A Self-Regulated Learning Approach

ERIC Educational Resources Information Center

Paulino, Paula; Sá, Isabel; Lopes da Silva, Adelina

2016-01-01

Introduction: The self-regulation of motivation (SRM) is conceptualized as a meta-motivational process that guides students' efforts and persistence when performing tasks. This process regulates students' behavior through strategies that are influenced by motivational beliefs. SRM allows students to motivate themselves and guides their behavior.…

An Improved Model Predictive Current Controller of Switched Reluctance Machines Using Time-Multiplexed Current Sensor

PubMed Central

Li, Bingchu; Ling, Xiao; Huang, Yixiang; Gong, Liang; Liu, Chengliang

2017-01-01

This paper presents a fixed-switching-frequency model predictive current controller using multiplexed current sensor for switched reluctance machine (SRM) drives. The converter was modified to distinguish currents from simultaneously excited phases during the sampling period. The only current sensor installed in the converter was time division multiplexing for phase current sampling. During the commutation stage, the control steps of adjacent phases were shifted so that sampling time was staggered. The maximum and minimum duty ratio of pulse width modulation (PWM) was limited to keep enough sampling time for analog-to-digital (A/D) conversion. Current sensor multiplexing was realized without complex adjustment of either driver circuit nor control algorithms, while it helps to reduce the cost and errors introduced in current sampling due to inconsistency between sensors. The proposed controller is validated by both simulation and experimental results with a 1.5 kW three-phase 12/8 SRM. Satisfied current sampling is received with little difference compared with independent phase current sensors for each phase. The proposed controller tracks the reference current profile as accurately as the model predictive current controller with independent phase current sensors, while having minor tracking errors compared with a hysteresis current controller. PMID:28513554

Determination of polycyclic aromatic hydrocarbons in fractions in asphalt mixtures using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization.

PubMed

Nascimento, Paulo Cicero; Gobo, Luciana Assis; Bohrer, Denise; Carvalho, Leandro Machado; Cravo, Margareth Coutinho; Leite, Leni Figueiredo Mathias

2015-07-01

An analytical method using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization for the determination of polycyclic aromatic hydrocarbons in asphalt fractions has been developed. The 14 compounds determined, characterized by having two or more condensed aromatic rings, are expected to be present in asphalt and are considered carcinogenic and mutagenic. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all of the compounds. The limits of detection ranged from 0.5 to 346.5 μg/L and the limits of quantification ranged from 1.7 to 1550 μg/L. The method was validated against a diesel particulate extract standard reference material (NIST SRM 1975), and the obtained concentrations agreed with the certified values. The method was applied to asphalt samples after its fractionation according to ASTM D4124 and the method of Green. The concentrations of the seven polycyclic aromatic hydrocarbons quantified in the sample ranged from 0.86 mg/kg for benzo[ghi]perylene to 98.32 mg/kg for fluorene. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method validation for chemical composition determination by electron microprobe with wavelength dispersive spectrometer

NASA Astrophysics Data System (ADS)

Herrera-Basurto, R.; Mercader-Trejo, F.; Muñoz-Madrigal, N.; Juárez-García, J. M.; Rodriguez-López, A.; Manzano-Ramírez, A.

2016-07-01

The main goal of method validation is to demonstrate that the method is suitable for its intended purpose. One of the advantages of analytical method validation is translated into a level of confidence about the measurement results reported to satisfy a specific objective. Elemental composition determination by wavelength dispersive spectrometer (WDS) microanalysis has been used over extremely wide areas, mainly in the field of materials science, impurity determinations in geological, biological and food samples. However, little information is reported about the validation of the applied methods. Herein, results of the in-house method validation for elemental composition determination by WDS are shown. SRM 482, a binary alloy Cu-Au of different compositions, was used during the validation protocol following the recommendations for method validation proposed by Eurachem. This paper can be taken as a reference for the evaluation of the validation parameters more frequently requested to get the accreditation under the requirements of the ISO/IEC 17025 standard: selectivity, limit of detection, linear interval, sensitivity, precision, trueness and uncertainty. A model for uncertainty estimation was proposed including systematic and random errors. In addition, parameters evaluated during the validation process were also considered as part of the uncertainty model.

Development and Validation of a Sensitive Method for Trace Nickel Determination by Slotted Quartz Tube Flame Atomic Absorption Spectrometry After Dispersive Liquid-Liquid Microextraction.

PubMed

Yolcu, Şükran Melda; Fırat, Merve; Chormey, Dotse Selali; Büyükpınar, Çağdaş; Turak, Fatma; Bakırdere, Sezgin

2018-05-01

In this study, dispersive liquid-liquid microextraction was systematically optimized for the preconcentration of nickel after forming a complex with diphenylcarbazone. The measurement output of the flame atomic absorption spectrometer was further enhanced by fitting a custom-cut slotted quartz tube to the flame burner head. The extraction method increased the amount of nickel reaching the flame and the slotted quartz tube increased the residence time of nickel atoms in the flame to record higher absorbance. Two methods combined to give about 90 fold enhancement in sensitivity over the conventional flame atomic absorption spectrometry. The optimized method was applicable over a wide linear concentration range, and it gave a detection limit of 2.1 µg L -1 . Low relative standard deviations at the lowest concentration in the linear calibration plot indicated high precision for both extraction process and instrumental measurements. A coal fly ash standard reference material (SRM 1633c) was used to determine the accuracy of the method, and experimented results were compatible with the certified value. Spiked recovery tests were also used to validate the applicability of the method.

Tracing lead pollution sources in abandoned mine areas using stable Pb isotope ratios.

PubMed

Yoo, Eun-Jin; Lee, Jung-A; Park, Jae-Seon; Lee, Khanghyun; Lee, Won-Seok; Han, Jin-Seok; Choi, Jong-Woo

2014-02-01

This study focused on Pb isotope ratios of sediments in areas around an abandoned mine to determine if the ratios can be used as a source tracer. For pretreatment, sediment samples were dissolved with mixed acids, and a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS, Nu plasma II) was used to investigate the Pb isotopic composition of the samples. The measured isotope ratios were then corrected for instrumental mass fractionation by measuring the (203)Tl/(205)Tl ratio. Repeated measurements with the NIST SRM 981 reference material showed that the precision of all ratios was below 104 ppm (±2σ) for 50 ng/g. The isotope ratios ((207)Pb/(206)Pb) found were 0.85073 ± 0.0004~0.85373 ± 0.0003 for the main stream, while they were 0.83736 ± 0.0010 for the tributary and 0.84393 ± 0.0002 for the confluence. A binary mixing equation for isotope ratios showed that the contributions of mine lead to neighboring areas were up to 60%. Therefore, Pb isotope ratios can be a good source tracer for areas around abandoned mines.

Determination of Iodate in Food, Environmental, and Biological Samples after Solid-Phase Extraction with Ni-Al-Zr Ternary Layered Double Hydroxide as a Nanosorbent

PubMed Central

Abdolmohammad-Zadeh, Hossein; Tavarid, Keyvan; Talleb, Zeynab

2012-01-01

Nanostructured nickel-aluminum-zirconium ternary layered double hydroxide was successfully applied as a solid-phase extraction sorbent for the separation and pre-concentration of trace levels of iodate in food, environmental and biological samples. An indirect method was used for monitoring of the extracted iodate ions. The method is based on the reaction of the iodate with iodide in acidic solution to produce iodine, which can be spectrophotometrically monitored at 352 nm. The absorbance is directly proportional to the concentration of iodate in the sample. The effect of several parameters such as pH, sample flow rate, amount of nanosorbent, elution conditions, sample volume, and coexisting ions on the recovery was investigated. In the optimum experimental conditions, the limit of detection (3s) and enrichment factor were 0.12 μg mL−1 and 20, respectively. The calibration graph using the preconcentration system was linear in the range of 0.2–2.8 μg mL−1 with a correlation coefficient of 0.998. In order to validate the presented method, a certified reference material, NIST SRM 1549, was also analyzed. PMID:22619590

Application of Solid Phase Extraction on Multiwalled Carbon Nanotubes of Some Heavy Metal Ions to Analysis of Skin Whitening Cosmetics Using ICP-AES

PubMed Central

ALqadami, Ayoub A.; Abdalla, Mohammad Abulhassan; ALOthman, Zeid A.; Omer, Kamal

2013-01-01

A novel and highly sensitive method for the determination of some heavy metals in skin whitening cosmetics creams using multiwalled carbon nanotubes MWCNTs as solid phase extraction sorbent for the preconcentration of these heavy metals prior to their determination by inductively coupled plasma atomic emission spectrometry is described. Different practical parameters have been thoroughly investigated and the optimum experimental conditions were employed. The developed method was then applied for the determination of arsenic, bismuth, cadmium, mercury, lead and titanium in samples of skin whitening cosmetics. The detection limits under these conditions for As, Bi, Cd, Pb, Hg and Ti were 2.4, 4.08, 0.3, 2.1, 1.8, and 1.8 ng·mL−1, respectively. The relative standard deviations (RSDs) were found to be less than 2.0%. For validation, a certified reference material of NIST SRM 1570a spinach leaves was analyzed and the determined values were in good agreement with the certified values. The recoveries for spiked samples were found to be in the range of 89.6–104.4%. PMID:23343988

Space shuttle system program definition. Volume 4: Cost and schedule report

NASA Technical Reports Server (NTRS)

1972-01-01

The supporting cost and schedule data for the second half of the Space Shuttle System Phase B Extension Study is summarized. The major objective for this period was to address the cost/schedule differences affecting final selection of the HO orbiter space shuttle system. The contending options under study included the following booster launch configurations: (1) series burn ballistic recoverable booster (BRB), (2) parallel burn ballistic recoverable booster (BRB), (3) series burn solid rocket motors (SRM's), and (4) parallel burn solid rocket motors (SRM's). The implications of varying payload bay sizes for the orbiter, engine type for the ballistics recoverable booster, and SRM motors for the solid booster were examined.

46 CFR Sec. 3 - General provisions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... thereof or if the contractor does not hold a Master Repair Contract under NSA-WORKSMALREP if the contract price does not exceed $2,000 and said contract is made in accordance with NSA Order 46 (SRM-5, Revised) and NSA Order 51 (SRM-6, Revised). (b) The repairs to or servicing of ships equipment, as covered by...

46 CFR Sec. 3 - General provisions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... thereof or if the contractor does not hold a Master Repair Contract under NSA-WORKSMALREP if the contract price does not exceed $2,000 and said contract is made in accordance with NSA Order 46 (SRM-5, Revised) and NSA Order 51 (SRM-6, Revised). (b) The repairs to or servicing of ships equipment, as covered by...

Agreement of Power Measures between Garmin Vector and SRM Cycle Power Meters

ERIC Educational Resources Information Center

Novak, Andrew R.; Dascombe, Benjamin J.

2016-01-01

This study aimed to determine if the Garmin Vector (Schaffhausen, Switzerland) power meter produced acceptable measures when compared with the Schoberer Rad Messetechnik (SRM; Julich, Germany) power meter across a range of high-intensity efforts. Twenty-one well-trained cyclists completed power profiles (seven maximal mean efforts between 5 and…

INTERLABORATORY COMPARISON OF MASS SPECTROMETRIC METHODS FOR LEAD ISOTOPES AND TRACE ELEMENTS IN NIST SRM 1400 BONE ASH

EPA Science Inventory

The results of an interlaboratory comparison are reported for he lead isotope composition and for trace element concentrations in NIST SRM 1400 Bone Ash obtained using quadrupole and magnetic-sector inductively coupled plasma mass spectrometry (ICP-MS) and (for the Pb isotopes on...

Correlation of Slag Expulsion with Ballistic Anomalies in Shuttle Solid Rocket Motors

NASA Technical Reports Server (NTRS)

Sambamurthi, Jay K.; Alvarado, Alexis; Mathias, Edward C.

1996-01-01

During the Shuttle launches, the solid rocket motors (SRM) occasionally experience pressure perturbations (8-13 psi) between 65-75 s into the motor burn time. The magnitudes of these perturbations are very small in comparison with the operating motor chamber pressure, which is over 600 psi during this time frame. These SRM pressure perturbations are believed to he caused primarily by the expulsion of slag (aluminum oxide). Two SRM static tests, TEM-11 and FSM-4, were instrumented extensively for the study of the phenomena associated with pressure perturbations. The test instrumentation used included nonintrusive optical and infrared diagnostics of the plume, such as high-speed photography, radiometers, and thermal image cameras. Results from all of these nonintrusive observations provide substantial circumstantial evidence to support the scenario that the pressure perturbation event in the Shuttle SRM is caused primarily by the expulsion of molten slag. In the static motor tests, the slag was also expelled preferentially near the bottom of the nozzle because of slag accumulation at the bottom of the aft end of the horizontally oriented motor.

Markov-random-field-based super-resolution mapping for identification of urban trees in VHR images

NASA Astrophysics Data System (ADS)

Ardila, Juan P.; Tolpekin, Valentyn A.; Bijker, Wietske; Stein, Alfred

2011-11-01

Identification of tree crowns from remote sensing requires detailed spectral information and submeter spatial resolution imagery. Traditional pixel-based classification techniques do not fully exploit the spatial and spectral characteristics of remote sensing datasets. We propose a contextual and probabilistic method for detection of tree crowns in urban areas using a Markov random field based super resolution mapping (SRM) approach in very high resolution images. Our method defines an objective energy function in terms of the conditional probabilities of panchromatic and multispectral images and it locally optimizes the labeling of tree crown pixels. Energy and model parameter values are estimated from multiple implementations of SRM in tuning areas and the method is applied in QuickBird images to produce a 0.6 m tree crown map in a city of The Netherlands. The SRM output shows an identification rate of 66% and commission and omission errors in small trees and shrub areas. The method outperforms tree crown identification results obtained with maximum likelihood, support vector machines and SRM at nominal resolution (2.4 m) approaches.

Space Shuttle SRM Ignition System. [Solid Rocket Motor

NASA Technical Reports Server (NTRS)

Bolieau, C. W.; Baker, J. S.; Folkman, S. L.

1978-01-01

This paper presents the Space Shuttle SRM Ignition System, which consists of a large solid propellant main igniter, a small solid propellant initiating igniter and an electromechanical safety and arming device containing two NASA Standard Initiators and a B-KNO3 pyrotechnic booster charge. In development motors, the igniter also has a valve through which CO2 is injected for post-firing quench of the SRM. The igniter has redundant, testable seals at all pressurized joints and three major reusable components; the case, the adapter, and the S&A device. Two development problem areas are discussed. One problem area was transverse mode combustion instability in the main igniter with maximum amplitude of 340 psi peak-to-peak at a frequency of 1500 Hz, which was reduced by a propellant grain configuration change and a change from a 2% aluminum content propellant to a formulation containing 10% aluminum. The other problem area was an excessively rapid rise of thrust in the SRM, which was reduced by reducing the igniter mass flow rate. This mass flow rate reduction was accomplished by removing portions of the grain starpoints in the head end.

Study of solid rocket motors for a space shuttle booster. Appendix D: Recovery and reuse 156-inch diameter solid rocket motor booster

NASA Technical Reports Server (NTRS)

1972-01-01

The baseline for a space shuttle configuration utilizing two parallel-burn, 156-in.-diameter SRMs with three segments and techroll seal movable nozzles is presented. The concept and general economic benefits of SRM recovery are equally valid for the series-burn SRMs, provided that those SRMs are also designed for the same strength, stiffness, segmentation, and interchangeability as the present design, and that those SRMs are also recovered as individual units. Feasibility studies were initiated to investigate SRM recoverability. These studies were based upon recovery of the SRM boosters for the Titan 3C. Ground rules precluded SRM modification that required significant changes in motor qualification or schedule. Even with this restriction, the study determined that the recoverable booster concept was completely feasible, both technically and economically. Parachute recovery has been selected as the best method, principally because it can accomplish the task with a minimum development cost and time to achieve operational recovery status. This system affords the highest probability for achieving large cost reductions.

Highly multiplexed targeted proteomics using precise control of peptide retention time.

PubMed

Gallien, Sebastien; Peterman, Scott; Kiyonami, Reiko; Souady, Jamal; Duriez, Elodie; Schoen, Alan; Domon, Bruno

2012-04-01

Large-scale proteomics applications using SRM analysis on triple quadrupole mass spectrometers present new challenges to LC-MS/MS experimental design. Despite the automation of building large-scale LC-SRM methods, the increased numbers of targeted peptides can compromise the balance between sensitivity and selectivity. To facilitate large target numbers, time-scheduled SRM transition acquisition is performed. Previously published results have demonstrated incorporation of a well-characterized set of synthetic peptides enabled chromatographic characterization of the elution profile for most endogenous peptides. We have extended this application of peptide trainer kits to not only build SRM methods but to facilitate real-time elution profile characterization that enables automated adjustment of the scheduled detection windows. Incorporation of dynamic retention time adjustments better facilitate targeted assays lasting several days without the need for constant supervision. This paper provides an overview of how the dynamic retention correction approach identifies and corrects for commonly observed LC variations. This adjustment dramatically improves robustness in targeted discovery experiments as well as routine quantification experiments. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Monitoring bacterial resistance to chloramphenicol and other antibiotics by liquid chromatography electrospray ionization tandem mass spectrometry using selected reaction monitoring.

PubMed

Haag, Anthony M; Medina, Audrie M; Royall, Ariel E; Herzog, Norbert K; Niesel, David W

2013-06-01

Antibiotic resistance is a growing problem worldwide. For this reason, clinical laboratories often determine the susceptibility of the bacterial isolate to a number of different antibiotics in order to establish the most effective antibiotic for treatment. Unfortunately, current susceptibility assays are time consuming. Antibiotic resistance often involves the chemical modification of an antibiotic to an inactive form by an enzyme expressed by the bacterium. Selected reaction monitoring (SRM) has the ability to quickly monitor and identify these chemical changes in an unprecedented time scale. In this work, we used SRM as a technique to determine the susceptibility of several different antibiotics to the chemically modifying enzymes β-lactamase and chloramphenicol acetyltransferase, enzymes used by bacteria to confer resistance to major classes of commonly used antibiotics. We also used this technique to directly monitor the effects of resistant bacteria grown in a broth containing a specific antibiotic. Because SRM is highly selective and can also identify chemical changes in a multitude of antibiotics in a single assay, SRM has the ability to detect organisms that are resistant to multiple antibiotics in a single assay. For these reasons, the use of SRM greatly reduces the time it takes to determine the susceptibility or resistance of an organism to a multitude of antibiotics by eliminating the time-consuming process found in other currently used methods. Copyright © 2013 John Wiley & Sons, Ltd.

Large-Scale SRM Screen of Urothelial Bladder Cancer Candidate Biomarkers in Urine.

PubMed

Duriez, Elodie; Masselon, Christophe D; Mesmin, Cédric; Court, Magali; Demeure, Kevin; Allory, Yves; Malats, Núria; Matondo, Mariette; Radvanyi, François; Garin, Jérôme; Domon, Bruno

2017-04-07

Urothelial bladder cancer is a condition associated with high recurrence and substantial morbidity and mortality. Noninvasive urinary tests that would detect bladder cancer and tumor recurrence are required to significantly improve patient care. Over the past decade, numerous bladder cancer candidate biomarkers have been identified in the context of extensive proteomics or transcriptomics studies. To translate these findings in clinically useful biomarkers, the systematic evaluation of these candidates remains the bottleneck. Such evaluation involves large-scale quantitative LC-SRM (liquid chromatography-selected reaction monitoring) measurements, targeting hundreds of signature peptides by monitoring thousands of transitions in a single analysis. The design of highly multiplexed SRM analyses is driven by several factors: throughput, robustness, selectivity and sensitivity. Because of the complexity of the samples to be analyzed, some measurements (transitions) can be interfered by coeluting isobaric species resulting in biased or inconsistent estimated peptide/protein levels. Thus the assessment of the quality of SRM data is critical to allow flagging these inconsistent data. We describe an efficient and robust method to process large SRM data sets, including the processing of the raw data, the detection of low-quality measurements, the normalization of the signals for each protein, and the estimation of protein levels. Using this methodology, a variety of proteins previously associated with bladder cancer have been assessed through the analysis of urine samples from a large cohort of cancer patients and corresponding controls in an effort to establish a priority list of most promising candidates to guide subsequent clinical validation studies.

Validity and reproducibility of the ErgomoPro power meter compared with the SRM and Powertap power meters.

PubMed

Duc, Sebastien; Villerius, Vincent; Bertucci, William; Grappe, Frederic

2007-09-01

The ErgomoPro (EP) is a power meter that measures power output (PO) during outdoor and indoor cycling via 2 optoelectronic sensors located in the bottom bracket axis. The aim of this study was to determine the validity and the reproducibility of the EP compared with the SRM crank set and Powertap hub (PT). The validity of the EP was tested in the laboratory during 8 submaximal incremental tests (PO: 100 to 400 W), eight 30-min submaximal constant-power tests (PO = 180 W), and 8 sprint tests (PO > 750 W) and in the field during 8 training sessions (time: 181 +/- 73 min; PO: approximately 140 to 160 W). The reproducibility was assessed by calculating the coefficient of PO variation (CV) during the submaximal incremental and constant tests. The EP provided a significantly higher PO than the SRM and PT during the submaximal incremental test: The mean PO differences were +6.3% +/- 2.5% and +11.1% +/- 2.1% respectively. The difference was greater during field training sessions (+12.0% +/- 5.7% and +16.5% +/- 5.9%) but lower during sprint tests (+1.6% +/- 2.5% and +3.2% +/- 2.7%). The reproducibility of the EP is lower than those of the SRM and PT (CV = 4.1% +/- 1.8%, 1.9% +/- 0.4%, and 2.1% +/- 0.8%, respectively). The EP power meter appears less valid and reliable than the SRM and PT systems.

Commercially Available Gas-Permeable Cell Culture Bags May Not Prevent Anoxia in Cultured or Shipped Islets

PubMed Central

Avgoustiniatos, E.S.; Hering, B.J.; Rozak, P.R.; Wilson, J.R.; Tempelman, L.A.; Balamurugan, A.N.; Welch, D.P.; Weegman, B.P.; Suszynski, T.M.; Papas, K.K.

2009-01-01

Prolonged anoxia has deleterious effects on islets. Gas-permeable cell culture devices can be used to minimize anoxia during islet culture and especially during shipment when elimination of gas-liquid interfaces is required to prevent the formation of damaging gas bubbles. Gas-permeable bags may have several drawbacks, such as propensity for puncture and contamination, difficult islet retrieval, and significantly lower oxygen permeability than silicone rubber membranes (SRM). We hypothesized that oxygen permeability of bags may be insufficient for islet oxygenation. We measured oxygen transmission rates through the membrane walls of three different types of commercially available bags and through SRM currently used for islet shipment. We found that the bag membranes have oxygen transmission rates per unit area about 100-fold lower than SRM. We solved the oxygen diffusion-reaction equation for 150-μm diameter islets seeded at 3000 islet equivalents per cm2, a density adequate to culture and ship an entire human or porcine islet preparation in a single gas-permeable device, predicting that about 40% of the islet volume would be anoxic at 22°C and about 70% would be anoxic at 37°C. Islets of larger size or islets accumulated during shipment would be even more anoxic. The model predicted no anoxia in islets similarly seeded in devices with SRM bottoms. We concluded that commercially available bags may not prevent anoxia during islet culture or shipment; devices with SRM bottoms are more suitable alternatives. PMID:18374080

A four-culture study of self-enhancement and adjustment using the social relations model: do alternative conceptualizations and indices make a difference?

PubMed

Church, A Timothy; Katigbak, Marcia S; Mazuera Arias, Rina; Rincon, Brigida Carolina; Vargas-Flores, José de Jesús; Ibáñez-Reyes, Joselina; Wang, Lei; Alvarez, Juan M; Wang, Congcong; Ortiz, Fernando A

2014-06-01

In the self-enhancement literature, 2 major controversies remain--whether self-enhancement is a cultural universal and whether it is healthy or maladaptive. Use of the social relations model (SRM; Kenny, 1994) might facilitate resolution of these controversies. We applied the SRM with a round-robin design in both friend and family contexts in 4 diverse cultures: the United States (n = 399), Mexico (n = 413), Venezuela (n = 290), and China (n = 222). Results obtained with social comparison, self-insight, and SRM conceptualizations and indices of self-enhancement were compared for both agentic traits (i.e., egoistic bias) and communal traits (i.e., moralistic bias). Conclusions regarding cultural differences in the prevalence of self-enhancement vs. self-effacement tendencies, and the relationship between self-enhancement and adjustment, varied depending on the index of self-enhancement used. For example, consistent with cultural psychology perspectives, Chinese showed a greater tendency to self-efface than self-enhance using social comparison and self-insight indices, particularly on communal traits in the friend context. However, no cultural differences were observed when perceiver and target effects were controlled using the SRM indices. In all cultures, self-enhancement indices were moderately consistent across friend and family contexts, suggesting traitlike tendencies. To a similar extent in all 4 cultures, self-enhancement tendencies, as measured by the SRM indices, were moderately related to self-rated adjustment, but unrelated, or less so, to observer-rated adjustment.

ECOSYSTEM IMPACTS OF GEOENGINEERING: A Review for Developing a Science Plan

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

Russell, Lynn M; Jackson, Robert B; Norby, Richard J

2012-01-01

Geoengineering methods are intended to reduce the magnitude of climate change, which is already having demonstrable effects on ecosystem structure and functioning. Two different types of activities have been proposed: solar radiation management (SRM), or sunlight reflection methods, which involves reflecting a small percentage of solar light back into space to offset the warming due to greenhouse gases, and carbon dioxide removal (CDR), which includes a range of engineered and biological processes to remove carbon dioxide (CO2) from the atmosphere. This report evaluates some of the possible impacts of CDR and SRM on the physical climate and their subsequent influencemore » on ecosystems, which include the risks and uncertainties associated with new kinds of purposeful perturbations to the Earth. Therefore, the question considered in this review is whether CDR and SRM methods would exacerbate or alleviate the deleterious impacts on ecosystems associated with climate changes that might occur in the foreseeable future.Geoengineering methods are intended to reduce the magnitude of climate change, which is already having demonstrable effects on ecosystem structure and functioning. Two different types of activities have been proposed: solar radiation management (SRM), or sunlight reflection methods, which involves reflecting a small percentage of solar light back into space to offset the warming due to greenhouse gases, and carbon dioxide removal (CDR), which includes a range of engineered and biological processes to remove carbon dioxide (CO2) from the atmosphere. This report evaluates some of the possible impacts of CDR and SRM on the physical climate and their subsequent influence on ecosystems, which include the risks and uncertainties associated with new kinds of purposeful perturbations to the Earth. Therefore, the question considered in this review is whether CDR and SRM methods would exacerbate or alleviate the deleterious impacts on ecosystems associated with climate changes that might occur in the foreseeable future.« less

Cost-Risk Trade-off of Solar Radiation Management and Mitigation under Probabilistic Information on Climate Sensitivity

NASA Astrophysics Data System (ADS)

Khabbazan, Mohammad Mohammadi; Roshan, Elnaz; Held, Hermann

2017-04-01

In principle solar radiation management (SRM) offers an option to ameliorate anthropogenic temperature rise. However we cannot expect it to simultaneously compensate for anthropogenic changes in further climate variables in a perfect manner. Here, we ask to what extent a proponent of the 2°C-temperature target would apply SRM in conjunction with mitigation in view of global or regional disparities in precipitation changes. We apply cost-risk analysis (CRA), which is a decision analytic framework that makes a trade-off between the expected welfare-loss from climate policy costs and the climate risks from transgressing a climate target. Here, in both global-scale and 'Giorgi'-regional-scale analyses, we evaluate the optimal mixture of SRM and mitigation under probabilistic information about climate sensitivity. To do so, we generalize CRA for the sake of including not only temperature risk, but also globally aggregated and regionally disaggregated precipitation risks. Social welfare is maximized for the following three valuation scenarios: temperature-risk-only, precipitation-risk-only, and equally weighted both-risks. For now, the Giorgi regions are treated by equal weight. We find that for regionally differentiated precipitation targets, the usage of SRM will be comparably more restricted. In the course of time, a cooling of up to 1.3°C can be attributed to SRM for the latter scenario and for a median climate sensitivity of 3°C (for a global target only, this number reduces by 0.5°C). Our results indicate that although SRM would almost completely substitute for mitigation in the globally aggregated analysis, it only saves 70% to 75% of the welfare-loss compared to a purely mitigation-based analysis (from economic costs and climate risks, approximately 4% in terms of BGE) when considering regional precipitation risks in precipitation-risk-only and both-risks scenarios. It remains to be shown how the inclusion of further risks or different regional weights would change that picture.

Validity and Responsiveness of the Short Version of the Western Ontario Rotator Cuff Index (Short-WORC) in Patients With Rotator Cuff Repair.

PubMed

Dewan, Neha; MacDermid, Joy C; MacIntyre, Norma

2018-05-01

Study Design Clinical measurement. Background Recently, the Western Ontario Rotator Cuff Index (WORC) was shortened, but few studies have reported its measurement properties. Objective To compare the validity and responsiveness of the short version of the Western Ontario Rotator Cuff Index (Short-WORC) and the WORC (disease-specific measures) with those of the Shoulder Pain and Disability Index (SPADI) and the simple shoulder test (SST) (joint-specific measures); the Disabilities of the Arm, Shoulder and Hand (DASH) (a region-specific measure); and the Medical Outcomes Study 12-Item Short-Form Health Survey version 2 (SF-12v2) (a general health status measure) in patients undergoing rotator cuff repair (RCR). Methods A cohort of patients (n = 223) completed the WORC, SPADI, SST, DASH, and SF-12v2 preoperatively and at 3 and 6 months after RCR. Short-WORC scores were extracted from the WORC questionnaire. The construct validity (Pearson correlations) and internal responsiveness (effect size [ES], standardized response mean [SRM], relative efficiency [RE]) of the Short-WORC were calculated. Results The Short-WORC was strongly correlated with the WORC (r = 0.89-0.96) and moderately to strongly correlated with non-disease-specific measures at preoperative and postoperative assessments (r = 0.51-0.92). The Short-WORC and WORC were equally responsive (RE Short-WORC/WORC = 1) at 0 to 6 months and highly responsive overall at 0 to 3 months (ES Short-WORC , 0.72; ES WORC , 0.92; SRM Short-WORC , 0.75; SRM WORC , 0.81) and 0 to 6 months (ES Short-WORC , 1.05; ES WORC , 1.12; SRM Short-WORC , 0.89; SRM WORC , 0.89). The responsiveness of the comparator measures (SPADI, SST, DASH, SF-12v2) was poor to moderate at 0 to 3 months (ES, 0.07-0.55; SRM, 0.09-0.49) and 0 to 6 months (ES, 0.05-0.78; SRM, 0.07-0.78). Conclusion The Short-WORC and WORC have similar responsiveness in patients undergoing RCR, and are more responsive than non-disease-specific measures. Future studies should focus on validation of the Short-WORC in samples representing the spectrum of rotator cuff disorders. J Orthop Sports Phys Ther 2018;48(5):409-418. doi:10.2519/jospt.2018.7928.

ATAQS: A computational software tool for high throughput transition optimization and validation for selected reaction monitoring mass spectrometry

PubMed Central

2011-01-01

Background Since its inception, proteomics has essentially operated in a discovery mode with the goal of identifying and quantifying the maximal number of proteins in a sample. Increasingly, proteomic measurements are also supporting hypothesis-driven studies, in which a predetermined set of proteins is consistently detected and quantified in multiple samples. Selected reaction monitoring (SRM) is a targeted mass spectrometric technique that supports the detection and quantification of specific proteins in complex samples at high sensitivity and reproducibility. Here, we describe ATAQS, an integrated software platform that supports all stages of targeted, SRM-based proteomics experiments including target selection, transition optimization and post acquisition data analysis. This software will significantly facilitate the use of targeted proteomic techniques and contribute to the generation of highly sensitive, reproducible and complete datasets that are particularly critical for the discovery and validation of targets in hypothesis-driven studies in systems biology. Result We introduce a new open source software pipeline, ATAQS (Automated and Targeted Analysis with Quantitative SRM), which consists of a number of modules that collectively support the SRM assay development workflow for targeted proteomic experiments (project management and generation of protein, peptide and transitions and the validation of peptide detection by SRM). ATAQS provides a flexible pipeline for end-users by allowing the workflow to start or end at any point of the pipeline, and for computational biologists, by enabling the easy extension of java algorithm classes for their own algorithm plug-in or connection via an external web site. This integrated system supports all steps in a SRM-based experiment and provides a user-friendly GUI that can be run by any operating system that allows the installation of the Mozilla Firefox web browser. Conclusions Targeted proteomics via SRM is a powerful new technique that enables the reproducible and accurate identification and quantification of sets of proteins of interest. ATAQS is the first open-source software that supports all steps of the targeted proteomics workflow. ATAQS also provides software API (Application Program Interface) documentation that enables the addition of new algorithms to each of the workflow steps. The software, installation guide and sample dataset can be found in http://tools.proteomecenter.org/ATAQS/ATAQS.html PMID:21414234

PCV Solid Rocket Motor: Design Status of the Motor Case Structure

NASA Astrophysics Data System (ADS)

Mataloni, A.; Zallo, A.; Perugini, P.; Di Cosmo, A.; Pasquale, N.; Mucci, R.

2014-06-01

For the VEGA Launch system new developments are running in order to allow: a) performances increase b) cost reduction c) introduction of new technologies.In the VEGA C configuration the PCV SRM replace the P80 in the first stage.The PCV design is based on the consolidate AVIO heritage with important improvements both from the material and from the technological side.Important improvements in skirts manufacturing will be tested as well, with the development of a customized automatic tape laying machine.From the material side a top class fiber will be selected on the bases of extensive trade-off plan which is under completion.The pre-preg material is based on an in-house resin formulation tailored to the specific motor case process requirements.

Reusable Solid Rocket Motor - Accomplishment, Lessons, and a Culture of Success

NASA Technical Reports Server (NTRS)

Moore, D. R.; Phelps, W. J.

2011-01-01

The Reusable Solid Rocket Motor (RSRM) represents the largest solid rocket motor (SRM) ever flown and the only human-rated solid motor. High reliability of the RSRM has been the result of challenges addressed and lessons learned. Advancements have resulted by applying attention to process control, testing, and postflight through timely and thorough communication in dealing with all issues. A structured and disciplined approach was taken to identify and disposition all concerns. Careful consideration and application of alternate opinions was embraced. Focus was placed on process control, ground test programs, and postflight assessment. Process control is mandatory for an SRM, because an acceptance test of the delivered product is not feasible. The RSRM maintained both full-scale and subscale test articles, which enabled continuous improvement of design and evaluation of process control and material behavior. Additionally RSRM reliability was achieved through attention to detail in post flight assessment to observe any shift in performance. The postflight analysis and inspections provided invaluable reliability data as it enables observation of actual flight performance, most of which would not be available if the motors were not recovered. RSRM reusability offered unique opportunities to learn about the hardware. NASA is moving forward with the Space Launch System that incorporates propulsion systems that takes advantage of the heritage Shuttle and Ares solid motor programs. These unique challenges, features of the RSRM, materials and manufacturing issues, and design improvements will be discussed in the paper.

Simulated impact of climate change on hydrology of multiple watersheds using traditional and recommended snowmelt runoff model methodology

USDA-ARS?s Scientific Manuscript database

For more than three decades, researchers have utilized the Snowmelt Runoff Model (SRM) to test the impacts of climate change on streamflow of snow-fed systems. In this study, the hydrological effects of climate change are modeled over three sequential years using SRM with both typical and recommende...

A General and Flexible Approach to Estimating the Social Relations Model Using Bayesian Methods

ERIC Educational Resources Information Center

Ludtke, Oliver; Robitzsch, Alexander; Kenny, David A.; Trautwein, Ulrich

2013-01-01

The social relations model (SRM) is a conceptual, methodological, and analytical approach that is widely used to examine dyadic behaviors and interpersonal perception within groups. This article introduces a general and flexible approach to estimating the parameters of the SRM that is based on Bayesian methods using Markov chain Monte Carlo…

Space Shuttle Projects

NASA Image and Video Library

1987-05-27

This photograph is a long shot view of a full scale solid rocket motor (SRM) for the solid rocket booster (SRB) being test fired at Morton Thiokol's Wasatch Operations in Utah. The twin boosters provide the majority of thrust for the first two minutes of flight, about 5.8 million pounds, augmenting the Shuttle's main propulsion system during liftoff. The major design drivers for the SRM's were high thrust and reuse. The desired thrust was achieved by using state-of-the-art solid propellant and by using a long cylindrical motor with a specific core design that allows the propellant to burn in a carefully controlled marner. Under the direction of the Marshall Space Flight Center, the SRM's are provided by the Morton Thiokol Corporation.

Determination of lead by hydride generation inductively coupled plasma mass spectrometry (HG-ICP-MS): on-line generation of plumbane using potassium hexacyanomanganate(III)

PubMed Central

Yilmaz, Vedat; Arslan, Zikri; Rose, LaKeysha

2012-01-01

A hydride generation (HG) procedure has been described for determination of Pb by ICP-MS using potassium hexacyanomanganate(III), K3Mn(CN)6, as an additive to facilitate the generation of plumbane (PbH4). Potassium hexacyanomanganate(III) was prepared in acidic medium as it was unstable in water. The stability of hexacyanomanganate(III) was examined in dilute solutions of HCl, HNO3 and H2SO4. The solutions prepared in 1% v/v/ H2SO4 were found to be stable for over a period of 24 h. The least suitable medium was 1% v/v HNO3. For generation of plumbane, acidic hexacyanomanganate(III) and sample solutions were mixed online along a 5-cm long tygon tubing (1.14 mm i.d.) and then reacted with 2% m/v sodium borohydride (NaBH4). A concentration of 0.5% m/v K3Mn(CN)6 facilitated the generation of PbH4 remarkably. In comparison to H2SO4, HCl provided broader working range for which optimum concentration was 1% v/v. No significant interferences were noted from transition metals and hydride forming elements, up to 0.5 μg mL−1 levels, except Cu which depressed the signals severely. The depressive effects in the presence of 0.1 μg mL−1 Cu were alleviated by increasing the concentration of K3Mn(CN)6 to 2% m/v. Under these conditions, the sensitivity was enhanced by a factor of at least 42 to 48. The detection limit (3s) was 0.008 μg L−1 for 208Pb isotope. Average signal-to-noise ratio (S/N) ranged between 18 and 20 for 1.0 μg mL−1 Pb solution. The accuracy of the method was verified by analysis of several certified reference materials, including Nearshore seawater (CASS-4), Bone ash (SRM 1400), and Mussel tissue (SRM 2976). The procedure was also successfully applied to the determination of Pb in coastal seawater samples by ICP-MS. PMID:23312310

Simultaneous measurement of sulfur and lead isotopes in sulfides using nanosecond laser ablation coupled with two multi-collector inductively coupled plasma mass spectrometers

NASA Astrophysics Data System (ADS)

Yuan, Honglin; Liu, Xu; Chen, Lu; Bao, Zhian; Chen, Kaiyun; Zong, Chunlei; Li, Xiao-Chun; Qiu, Johnson Wenhong

2018-04-01

We herein report the coupling of a nanosecond laser ablation system with a large-scale multi-collector inductively coupled plasma mass spectrometer (Nu1700 MC-ICPMS, NP-1700) and a conventional Nu Plasma II MC-ICPMS (NP-II) for the simultaneous laser ablation and determination of in situ S and Pb isotopic compositions of sulfide minerals. We found that the required aerosol distribution between the two spectrometers depended on the Pb content of the sample. For example, for a sulfide containing 100-3000 ppm Pb, the aerosol was distributed between the NP-1700 and the NP-II spectrometers in a 1:1 ratio, while for lead contents >3000 and <100 ppm, these ratios were 5:1 and 1:3, respectively. In addition, S isotopic analysis showed a pronounced matrix effect, so a matrix-matched external standard was used for standard-sample bracketing correction. The NIST NBS 977 (NBS, National Bureau of Standards; NIST, National Institute of Standards & Technology) Tl (thallium) dry aerosol internal standard and the NIST SRM 610 (SRM, standard reference material) external standard were employed to obtain accurate results for the analysis of Pb isotopes. In tandem experiments where airflow conditions were similar to those employed during stand-alone analyses, small changes in the aerosol carrier gas flow did not significantly influence the accurate determination of S and Pb isotope ratios. In addition, careful optimization of the flow ratio of the aerosol carrier (He) and makeup (Ar) gases to match stand-alone analytical conditions allowed comparable S and Pb isotope ratios to be obtained within an error of 2 s analytical uncertainties. Furthermore, the results of tandem analyses obtained using our method were consistent with those of previously reported stand-alone techniques for the S and Pb isotopes of chalcopyrite, pyrite, galena, and sphalerite, thus indicating that this method is suitable for the simultaneous analysis of S and Pb isotopes of natural sulfide minerals, and provides an effective tool to determine S and Pb isotope compositions of sulfides formed through multi-stage deposition routes.

Automated selected reaction monitoring data analysis workflow for large-scale targeted proteomic studies.

PubMed

Surinova, Silvia; Hüttenhain, Ruth; Chang, Ching-Yun; Espona, Lucia; Vitek, Olga; Aebersold, Ruedi

2013-08-01

Targeted proteomics based on selected reaction monitoring (SRM) mass spectrometry is commonly used for accurate and reproducible quantification of protein analytes in complex biological mixtures. Strictly hypothesis-driven, SRM assays quantify each targeted protein by collecting measurements on its peptide fragment ions, called transitions. To achieve sensitive and accurate quantitative results, experimental design and data analysis must consistently account for the variability of the quantified transitions. This consistency is especially important in large experiments, which increasingly require profiling up to hundreds of proteins over hundreds of samples. Here we describe a robust and automated workflow for the analysis of large quantitative SRM data sets that integrates data processing, statistical protein identification and quantification, and dissemination of the results. The integrated workflow combines three software tools: mProphet for peptide identification via probabilistic scoring; SRMstats for protein significance analysis with linear mixed-effect models; and PASSEL, a public repository for storage, retrieval and query of SRM data. The input requirements for the protocol are files with SRM traces in mzXML format, and a file with a list of transitions in a text tab-separated format. The protocol is especially suited for data with heavy isotope-labeled peptide internal standards. We demonstrate the protocol on a clinical data set in which the abundances of 35 biomarker candidates were profiled in 83 blood plasma samples of subjects with ovarian cancer or benign ovarian tumors. The time frame to realize the protocol is 1-2 weeks, depending on the number of replicates used in the experiment.

Predicting the optical observables for nucleon scattering on even-even actinides

NASA Astrophysics Data System (ADS)

Martyanov, D. S.; Soukhovitskiĩ, E. Sh.; Capote, R.; Quesada, J. M.; Chiba, S.

2017-09-01

The previously derived Lane consistent dispersive coupled-channel optical model for nucleon scattering on 232Th and 238U nuclei is extended to describe scattering on even-even actinides with Z = 90-98. A soft-rotator-model (SRM) description of the low-lying nuclear structure is used, where the SRM Hamiltonian parameters are adjusted to the observed collective levels of the target nucleus. SRM nuclear wave functions (mixed in K quantum number) have been used to calculate the coupling matrix elements of the generalized optical model. The “effective” deformations that define inter-band couplings are derived from the SRM Hamiltonian parameters. Conservation of nuclear volume is enforced by introducing a dynamic monopolar term to the deformed potential, leading to additional couplings between rotational bands. The fitted static deformation parameters are in very good agreement with those derived by Wang and collaborators using the Weizsäcker-Skyrme global mass model (WS4), allowing use of the latter to predict cross sections for nuclei without experimental data. A good description of the scarce “optical” experimental database is achieved. SRM couplings and volume conservation allow a precise calculation of the compound-nucleus formation cross sections, which is significantly different from that calculated with rigid-rotor potentials coupling the ground-state rotational band. The derived parameters can be used to describe both neutron- and proton-induced reactions. Supported by International Atomic Energy Agency, through the IAEA Research Contract 19263, by the Spanish Ministry of Economy and Competitivity under Contracts FPA2014-53290-C2-2-P and FPA2016-77689-C2-1-R.

Estimating option values of solar radiation management assuming that climate sensitivity is uncertain

PubMed Central

Arino, Yosuke; Akimoto, Keigo; Sano, Fuminori; Homma, Takashi; Oda, Junichiro; Tomoda, Toshimasa

2016-01-01

Although solar radiation management (SRM) might play a role as an emergency geoengineering measure, its potential risks remain uncertain, and hence there are ethical and governance issues in the face of SRM’s actual deployment. By using an integrated assessment model, we first present one possible methodology for evaluating the value arising from retaining an SRM option given the uncertainty of climate sensitivity, and also examine sensitivities of the option value to SRM’s side effects (damages). Reflecting the governance challenges on immediate SRM deployment, we assume scenarios in which SRM could only be deployed with a limited degree of cooling (0.5 °C) only after 2050, when climate sensitivity uncertainty is assumed to be resolved and only when the sensitivity is found to be high (T2x = 4 °C). We conduct a cost-effectiveness analysis with constraining temperature rise as the objective. The SRM option value is originated from its rapid cooling capability that would alleviate the mitigation requirement under climate sensitivity uncertainty and thereby reduce mitigation costs. According to our estimates, the option value during 1990–2049 for a +2.4 °C target (the lowest temperature target level for which there were feasible solutions in this model study) relative to preindustrial levels were in the range between $2.5 and $5.9 trillion, taking into account the maximum level of side effects shown in the existing literature. The result indicates that lower limits of the option values for temperature targets below +2.4 °C would be greater than $2.5 trillion. PMID:27162346