National Institute Of Standards & Technology Research Articles

Determination of 241Am in Urine Using Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS).

Quantification of 241Am in urine at low levels is important for assessment of individuals' or populations' accidental, environmental, or terrorism-related internal contamination, but no convenient, precise method has been established to rapidly determine these low levels. Here we report a new analytical method to measure 241Am as developed and validated at the Centers for Disease Control and Prevention (CDC) by means of the selective retention of Am from urine directly on DGA resin, followed by SF-ICP-MS detection. The method provides rapid results with a Limit of Detection (LOD) of 0.22 pg/L (0.028 Bq/L), which is lower than 1/3 of the C/P CDG for 241Am at 5 days post-exposure. The results obtained by this method closely agree with CDC values as measured by Liquid Scintillation Counting, and with National Institute of Standards Technology (NIST) Certified Reference Materials (CRM) target values.

NEURAL NETWORK BASED CRYPTOGRAPHY

In this paper, neural network based cryptology is performed. The sys- tem consists of two stages. In the first stage, neural network-based pseudo-random numbers (NPRNGs) are generated and the results are tested for randomness us- ing National Institute of Standard Technology (NIST) randomness tests. In the second stage, a neural network-based cryptosystem is designed using NPRNGs. In this cryptosystem, data, which is encrypted by non-linear techniques, is subject to decryption attempts by means of two identical artificial neural networks (ANNs). With the first neural network, non-linear encryption is modeled using relation- building functionality. The encrypted data is decrypted with the second neural network using decision-making functionality.

In vitro and in silico studies on the anticancer and apoptosis-inducing activities of the sterols identified from the soft coral, subergorgia reticulata

Background:Gorgonians and other octocorals are known to possess a huge array of secondary metabolites in which sterols are the major group of secondary metabolites apart from sesquiterpenes and diterpenes, and the bioactive metabolites could show marked biomedical potential for future drug discovery.Objective:This study was intended for the isolation and identification of sterols from the octocoral Subergorgia reticulata and to evaluate the anticancer and apoptosis-inducing activities of the identified sterols through in vitro and in silico approach.Materials and Methods:The organism was collected from Lakshadweep Island. The isolated sterols were identified using Gas chromatography-mass spectrometry (GC-MS). The structure was confirmed by using comparison of their spectra those in National Institute of Standard Technology (NIST) library. The apoptosis inducing effect of identified sterols were determined by PASS online prediction. In vitro cytotoxity studies were carried out using Dalton's lymphoma ascites cells (DLA) and the cell viability was determined by trypan blue exclusion method.Results:Six sterols were identified from the soft coral S. reticulata. They are Cholesta-5,22-diene-3ol (3β), Ergosta-5-22-dien-3ol (3β,22E 24S), Cholesterol, 26,26-Dimethyl-5,24(28)-ergostadien-3β-ol. β-sitosterol, and Fucosterol. In silico predictions showed that the identified sterols exhibited remarkable apoptosis agonist activity. The probability of apoptosis agonist activity were found maximum for 26,26-Dimethyl-5,24 (28)-S. reticulata sterol fractions isolated were found to be having anticancer activity.Conclusions:These findings suggest that S. reticulata contained biologically active sterol compounds that may be useful in the treatment of cancer.

CYBERSECURITY White House could offer firms incentives to adopt digital defenses

The White House says it may offer legal protections, less expensive insurance, and other incentives to encourage companies that own or operate “critical infrastructure”—including chemical plants, electric grids, and water systems—to join an evolving national cybersecurity program. The inducements stem from an executive order President Barack Obama issued in February. That order calls for the National Institute of Standards & Technology (NIST) to work with industry to create a voluntary set of cybersecurity best practices to help safeguard critical computer systems from crippling hacker attacks. NIST is required to produce a draft cybersecurity framework by October and publish a final version by February 2014 ( C&EN, March 18, page 8). The American Chemistry Council, an industry trade group, says it is encouraged that the White House “has recognized the important role that incentives can play in meeting the overall goals of the cybersecurity executive order.” To prod companies into adopting ...

Requirements Analysis for Safer Ambulance Patient Compartments

Providing emergency care services in the confined space of the patient compartment of a moving ambulance has proven a hazardous activity. A National Institute of Standards & Technology (NIST)/Department of Homeland Security (DHS) project is applying systems engineering approaches to analyze requirements and develop design guidance that will improve Emergency Medical Services (EMS) workers’ safety while optimizing patient care. The analysis of an ambulance's patient compartment requires multiple disciplines such as ergonomics and crashworthiness. Systems engineering tools provide a platform to perform the analysis by bridging these disciplines and bringing information sources together.In the first phase of this project we compiled a number of requirements from the results of literature reviews, a nationwide web survey, workshops and focus group meetings. The next phase entails our process for reconciling potentially conflicting requirements from use case scenarios and then determining which constraints and metrics to be used for trade-off analysis and optimization in a human simulation modeling tool. The results of this analysis are being used to develop ambulance patient compartment design recommendations that will be provided as inputs to current and emerging ambulance design standards. In this paper we report on our efforts to provide science-based recommendations that may be used as a basis to revise and enhance current ambulance design standards and practices.

Determination of mercury in phosphate fertilizers by cold vapor atomic absorption spectrometry

In this paper, a method for the determination of mercury in phosphate fertilizers using slurry sampling and cold vapor atomic absorption spectrometry (CV QT AAS) is proposed. Because mercury (II) ions form strong complexes with phosphor compounds, the formation of metallic mercury vapor requires the presence of lanthanum chloride as a release agent. Thiourea increases the amount of mercury that is extracted from the solid sample to the liquid phase of the slurry. The method is established using two steps. First, the slurry is prepared using the sample, lanthanum chloride, hydrochloric acid solution and thiourea solution and is sonicated for 20min. Afterward, mercury vapor is generated using an aliquot of the slurry in the presence of the hydrochloric acid solution and isoamylic alcohol with sodium tetrahydroborate solution as the reducing agent. The experimental conditions for slurry preparation were optimized using two-level full factorial design involving the factors: thiourea and lanthanum chloride concentrations and the duration of sonication.The method allows the determination of mercury by external calibration using aqueous standards with limits of detection and quantification of 2.4 and 8.2μgkg−1, respectively, and precision, expressed as relative standard deviation, of 6.36 and 5.81% for two phosphate fertilizer samples with mercury concentrations of 0.24 and 0.57mgkg−1, respectively. The accuracy was confirmed by the analysis of a certified reference material of phosphate fertilizer that was provided by the National Institute of Standards & Technology (NIST). The method was applied to determine mercury in six commercial samples of phosphate fertilizers. The mercury content varied from 33.97 to 209.28μgkg−1. These samples were also analyzed employing inductively coupled plasma mass spectrometry (ICP-MS). The ICP-MS results were consistent with the results from our proposed method.

Analysis of carcinogenic polycyclic aromatic hydrocarbons in complex environmental mixtures by LC-APPI-MS/MS

Here we developed a highly sensitive, fast and reliable liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the detection and analysis of 16 different polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs that have been identified as carcinogens and classified according to their biological potency. Comparison to standard analysis procedures based on gas chromatography–mass spectrometry (GC–MS) instrumentation demonstrated an improved easiness of sample preparation and sensitivity of detection achieved with the new LC-MS/MS method employing an atmospheric pressure photoionization (APPI) source attached to an API 4000 mass spectrometer (LC-APPI-MS/MS). The favorable outcome could be confirmed by analyzing complex mixtures such as certain Standard Reference Materials (SRMs) obtained from the National Institute of Standards & Technology (NIST), i.e., SRM 1975 and SRM 2975, and several diesel exhaust soots provided by the German automobile industry. Certified concentrations of individual analytes provided by NIST not only could be confirmed, but additional extremely potent carcinogens such as several isomeric hexacyclic dibenzopyrenes (DBPs), 5-methylchrysene (5-MC), and others have been detected in these crude samples in a concentration range down to below 1 ng g −1 raw material.

Identification of Keys and Cryptographic Algorithms Using Genetic Algorithm and Graph Theory

This paper describes genetic algorithms that use the Calisnki-Harabasz index as its evaluation function and graphs techniques that are both used to identify patterns in cryptograms generated by cryptographies algorithms certified by NIST (National Institute Standard Technology), namely AES, RC6, MARS, Twofish and Serpent. Evidence of patterns or "signatures" generated by the algorithms under test were detected, thus corroborating the results of other studies quoted here. The results obtained with these two techniques are compared with results reported, showing superiority in the accuracy of class generation.

Study on the Effects of Characteristic Polynomial in LFSR for Randomness Quality

Randomness quality of keys becomes an essential in secure communications, since the security of modern cryptographic techniques relies on unpredictable and irreproducible digital keys which are generated by random number generator (RNG). This study focuses on the effects of characteristic polynomial in linear feedback shift registers (LFSR) for randomness quality. RNG's output is produced by integrating binary random source based on optic and LFSR. In this observation, randomness of the RNG's output with different characteristic polynomials has been tested using National Institute of Standards & Technology (NIST) test. The result shows that RNG with LFSR which is characterized by a feedback being a primitive polynomial of n-1 passes all the NISTstandard statistical tests.

APPLICATION OF NEUTRON ACTIVATION ANALYSIS IN CHARACTERIZATION OF ENVIRONMENTAL SRM SAMPLES

Neutron activation analysis (NAA) is a nuclear technique that is excellent, multi-elemental, sensitive and has limit detection up to nanogram level. The application of NAA in analysis of Standard Reference Material (SRM) National Institute of Standard Technology (NIST) 1633b Coal Fly Ash and SRM NIST 1646a Estuarine Sediment was carried out for NAA laboratory inter-comparison program. The samples were distributed by Technology Centre for Nuclear Industry Material, National Nuclear Energy Agency as a coordinator of the inter-comparison program. The samples were irradiated in rabbit facility of G.A. Siwabessy reactor with neutron flux ~ 1013 n.cm-2.s-1, and counted with HPGe spectrometry gamma detector. Several trace elements in these samples were detected. The concentration of Al, Mg, K, Na and Ti in SRM NIST 1633b were 15.11, 7.35, 2.09, 0.192 and 0.756% respectively and the concentration of As, Cr, Mn, Se, V, Sb, Co, Cs, La, Sc and Sm were 137.0, 195.6, 129.4, 9.61, 305.8, 5.45, 56.2, 11.18, 83.73, 41.1 and 19.13 mg/kg respectively. The analysis result in SRM NIST 1646a of the concentration of Al and Na were 2.15 and 0.70% and the concentration of As, Cr, Co, La and Sc were 5.75, 36.3, 4.58, 15.67 and 4.00 mg/kg respectively. These results analysis had relative bias and u-test ranged from 0.4-11.3% and 0.15-2.25. The accuracy and precision evaluation based on International Atomic Energy Agency (IAEA) criteria was also applied. The result showed that NAA technique is applicable for the environmental samples analysis, and it also showed that the NAA laboratory in BATAN Bandung has a good performance. Keywords: NAA, inter-comparison, estuarine sediment, coal fly ash, environmental samples

Towards a Culture of Application: Science and Decision Making at the National Institute of Standards & Technology

How does the research performed by a government mission agency contribute to useable technologies for its constituents? Is it possible to incorporate science policy mechanisms for increasing benefits to users in the decision process? The United States National Institute of Standards & Technology (NIST) promises research directed towards industrial application. This paper considers the processes that produce science and technology at NIST. The institute’s policies for science provide robust examples for how effective science policies can contribute to the emergence of useful technologies. To progress towards technologies that can be years away, the agency uses several means for integrating the needs of eventual information users into the prioritization process. To accomplish this, NIST units, such as the Materials Science and Engineering Laboratory, incorporate mechanisms for considering user need and project impact into different stages of its scientific decision processes. This, and other specific strategies that the agency utilizes for connecting the supply of science to information demand, provide lessons for generating useable science.

An Automated Hydride Generation Interface to ICPMS for Measuring Total Arsenic in Environmental Samples

An automated hydride generation (AHG) interface to inductive coupled plasma mass spectroscopy (ICPMS) was developed for measuring arsenic in environmental samples. This technique provides statistically indistinguishable response slopes (within about 3%) for hydride generation-ICPMS (HG-ICPMS) analysis of all major As species, inorganic As(III), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), and inorganic As(V); this has not previously been achieved. Previously, sample pretreatment to convert all forms of As into As(V) has been a prerequisite for measuring total arsenic in complex matrices. Under our operating conditions, arsenobetaine (AsB), until now regarded to be inert, also generates a hydride (albeit the response is only approximately 7% of others). The limit of detection (LOD) based on three times the standard deviation of the blank with this technique for AsB, DMA, As(III), MMA, and As(V) is 90, 66, 63, 63, and 63 pg As, respectively. This AHG-ICPMS technique was compared with a flow injection-UV photolysis-HG-ICPMS (FI-UV-ICPMS) and liquid chromatography-UV-HG-ICPMS analysis of arsenic content in National Institute of Standards & Technology (NIST) standard rice flour (standard reference material: SRM 1568a) and rice samples collected from West Bengal, India. Both oxidative acid digestion and methanol:water (1:1) extraction were used. The analytical results for total As in the SRM 1568a digest were 99.2 +/- 0.6 and 100.2 +/- 0.8% of the certified value (290 +/- 3 microg As/kg) by the AHG-ICPMS and the FI-UV-HG-ICPMS techniques, respectively. For rice extracts and the digests, the two techniques provided results that were correlated with linear r2 values of 0.9988 and 0.9987 with intercepts statistically indistinguishable from zero. Chromatographic analysis indicated that As in these rice samples were 75-90% inorganic.

Differential Pulmonary Retention of Diesel Exhaust Particles in Wistar Kyoto and Spontaneously Hypertensive Rats

Spontaneously hypertensive (SH) and normotensive Wistar Kyoto (WKY) rats have been used for understanding the mechanisms of variations in susceptibility to airborne pollutants. We examined the lung burden of diesel exhaust particles (DEP) following inhalation of diesel engine exhaust (DEE) in both strains. The kinetics of clearance was also examined after single intratracheal (IT) instillation of DEP. Lungs were analyzed for DEP elemental carbon (EC) after exposure to DEE (0, 500, or 2000 microg/m(3) 4 h/day, 5 days/week x 4 weeks). SH rats had 16% less DEP-EC at 500 and 32% less at 2000 microg/m(3) in the lungs, despite having 50% higher than the average minute volume. No strain-related differences were noted in number of alveolar macrophages or their average DEP load as evident from examining cells in bronchoalveolar lavage fluid (BALF). The kinetics of DEP clearance from lungs of male WKY and SH rats was studied following a single instillation at 0.0 or 8.33 mg/kg of DEP standard reference material (SRM 2975) from the National Institute of Standards Technology. SH rats cleared 60% DEP over 112 days while minimal clearance occurred from the lungs of WKY. The pattern of DEP-induced inflammatory response assessed by BALF analysis was similar in both strains, although the overall protein leak was slightly greater in SH rats. A time-dependent accumulation of DEP occurred in tracheal lymph nodes of both strains (SH > WKY). Thus, SH rats may clear DEP more efficiently from their lungs than normotensive WKY rats, with a small contribution of more effective lymphatic drainage.

FUNDING FOR AMERICA COMPETES ACT

WHEN PRESIDENT Barack Obama committed $787 billion of taxpayers’ money to stimulate the economy, he chose to sign the American Recovery & Reinvestment Act (ARRA) of 2009 at the Denver Museum of Nature & Science. The symbolic venue underscores Obama’s commitment to boosting the economy through science and technology. ARRA provides as much as $21.5 billion in federal research and development funding, according to estimates by the American Association for the Advancement of Science. Of that, almost $5.2 billion goes to the three science agencies identified for increased funding by the America Competes Act (ACA): the National Science Foundation, the National Institute of Standards & Technology (NIST), and the Department of Energy’s Office of Science (DOE OS). “Just as President Kennedy sparked an explosion of innovation when he set America’s sights on the moon, I hope this investment will ignite our imagination once more, spurring new discoveries and breakthroughs in science, in medicine, in energy, ...

NIST PLAYS FOR HIGH STAKES

SMALL AND MEDIUM -sized U.S. companies, as well as universities and nonprofit organizations, pursuing high-risk research have a new path to federal funding in the Technology Innovation Program (TIP) of the National Institute of Standards & Technology (NIST). The program will award financial support for up to nine projects in the fall, but funding beyond 2008 is uncertain. TIP replaces NIST’s embattled Advanced Technology Program (ATP), which the Bush Administration eliminated last year. The new program, which is similar in some ways to ATP, supports U.S. innovation by funding high-risk research, but TIP requires that projects be focused on areas of critical national need. As part of the legislation that established TIP in 2007, ongoing ATP programs can continue to receive support under TIP. “The key thing to understand is that TIP is not ATP. It is a new and different program, with different goals,” TIP Program Director Marc G. Stanley emphasizes when asked to compare ...

Determination of Al, Cr, Fe, Zn, Cd, Pb and Bi in Crude Drugs by Inductively Coupled Plasma Atomic Emission Spectrometry after Coprecipitation with Yttrium Phosphate

A novel method that combines inductively coupled plasma atomic emission spectrometry (ICPAES) with a coprecipitation technique to determine trace and sub-trace elements in crude drugs is described herein. Yttrium phosphate quantitatively coprecipitated seven elements (Al, Cr, Fe, Zn, Cd, Pb and Bi) at pH 6 in a solution prepared from microwave-digested samples of crude drugs. Some matrix elements such as Na, K, Mg and Ca were effectively removed by this process. The thus coprecipitated elements were then determined by ICPAES with yttrium as an internal standard element. The detection limits (3σ, n=10) were 0.17 mg/kg for Al, 0.004 mg/kg for Cr, 0.03 mg/kg for Fe, 0.13 mg/kg for Zn, 0.004 mg/kg for Cd, 0.19 mg/kg for Pb and 0.06 mg/kg for Bi. The proposed method was successfully utilized to determine the concentration of the above-mentioned seven elements in standard reference materials [National Institute of Standards Technology (NIST) SRM1515, SRM1547 and SRM1575a] and seven kinds of crude drugs.

Mineral composition of wheat flour consumed in Brazilian cities

In the present paper, the mineral composition of wheat flour consumed in Brazil was evaluated. In the sampling step 54 samples were collected in 15 cities, including principal Brazilian cities such as: Sao Paulo, Rio de Janeiro, Salvador, Porto Alegre, Recife and others. The elements determinate were: calcium, copper, magnesium, manganese, iron, phosphorus, potassium and zinc. The samples were digested using nitric acid and hydrogen peroxide in open system. The analytical technique employed was Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES). The method validation (including digestion and determination) was performed using a certified reference material of wheat flour furnished by National Institute of Standards & Technology (NIST). Considering the 54 samples analyzed, the results demonstrated that the macronutrients: calcium, magnesium, potassium and phosphorus have average contents of 0.27, 0.35, 1.71 and 1.92 mg g-1, for concentration ranges of 0.11-1.96, 0.19-0.51, 0.76-3.16 and 0.81-7.15 mg g-1, respectively. The micronutrients: copper, iron, manganese and zinc have average contents of 1.84, 37.8, 8.2 and 9.4 µg g-1, for concentration ranges of 1.00-2.80, 10.5-146.6, 3.9-14.7 and 5.1-13.9 µg g-1, respectively. The results were also evaluated using the multivariate analysis techniques: principal component analysis (PCA) and hierarchical cluster analysis (HCA).

A Simple Direct Injection Method for GC/MS Analysis of PAHs in Particulate Matter

A simple direct injection method for analysis of polycyclic aromatic hydrocarbons (PAHs) or other organic components of particulate matter by gas chromatography/mass spectrometry (GC/MS) was developed. This method uses a small custom brass capsule to insert a particulate sample deposited on a quartz fiber filter or powdery sample directly into a GC injector inlet. This approach was applied in the analysis of PAHs in diesel emissions and other particulate samples, which are introduced into the GC and analyzed by MS using selected ion monitoring mode. Quantitation is based on the concentration of PAHs in a standard reference material (SRM), which are certified by US National Institute of Standard Technology to avoid matrix effects on extraction efficiency. A standard filter is prepared by deposition of small amount of SRM of diesel particulate or ambient PM on quartz fiber filter. By this method, the linearity for 12 kinds of PAHs (3 to 6 rings) was demonstrated from 0.022 mg to 0.65 mg of SRM 1650. The linearity of BaP, for example, was confirmed from 0.028 to 0.845 ng. The reproducibility of this method determined by analyzing the standard filter was 15.4%. By selecting an appropriate SRM as a standard material, this method is applicable for analyzing PAHs in fine particulate matter of less than 1 microm from various origins. Preliminary results for a series of ambient particulate matter, roadside PM, diesel soot and sidestream smoke, are presented. This method enables analysis of organic chemical substances, for example PAHs, in PM without any pretreatment using organic solvent, and without any expensive modification of GC instrument.

Non-occupational lead exposure and hypertension in Pakistani adults

Hypertension is one of the most prevalent diseases in the developed and developing countries. Based on the long historical association and the provocative findings of blood pressure effects at low level of lead exposure a study was carried out to determine if an association existed between low blood lead concentration and hypertension. In this study the effects of low-level exposure to lead on blood pressure were examined among 244 adults using atomic absorption spectrometer. For quality assurance purpose certified reference materials i.e., Animal blood A-13, Bovine liver 1577 and cotton cellulose V-9 from IAEA (International Atomic Energy Agency) and NIST (National Institute of Standard Technology) were analyzed under identical experimental conditions. The mean age of hypertensive adults was 52 years (range 43 - 66). The mean values of systolic and diastolic blood pressure were (209+/-11.7) (range 170 - 250) and (117+/-3.9) (range 105 - 140) mmHg respectively. Blood lead concentration ranged from 78 - 201 microg/L with a mean of 139 microg/L and 165 - 497 microg/L with a mean of 255 microg/L in normal and hypertensive adults respectively. Increase in systolic blood pressure was significantly predictive with increase in blood lead levels. Body mass index (BMI) and lipid profile including total cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol and triglyceride correlated with blood pressure.

Disseminator for rapid, selectable, and quantitative delivery of low and semivolatile liquid species to the vapor phase

Nelson and Griggs [Rev. Sci. Instrum. 39, 927 (1968)] introduced a quantitative method for disseminating liquid samples to the vapor phase using a lead screw to depress the plunger of a syringe whose body was heated and whose ambient tip was placed into the flow of a carrier gas. In order to measure quantitative vapor-phase infrared spectra, we have modified a commercial device to improve the accuracy and precision for quantitative vapor delivery. Design changes have focused on disseminating reactive or low volatility liquids by heating only the syringe tip and dispensed liquid. Performance features include quantitative vapor-phase generation with greater than three orders of magnitude concentration range, including low volatility species, with most equilibration times <40s. The method has been vetted by comparing the derived gas-phase infrared data versus IR spectra taken using both gravimetric (National Institute of Standards Technology) and passive vapor generation (Pacific Northwest National Laboratory) techniques. Quantitative vapor spectra of low volatility samples are reported.