Science.gov

Sample records for active sampling method

  1. Neutron activation analysis of certified samples by the absolute method

    NASA Astrophysics Data System (ADS)

    Kadem, F.; Belouadah, N.; Idiri, Z.

    2015-07-01

    The nuclear reactions analysis technique is mainly based on the relative method or the use of activation cross sections. In order to validate nuclear data for the calculated cross section evaluated from systematic studies, we used the neutron activation analysis technique (NAA) to determine the various constituent concentrations of certified samples for animal blood, milk and hay. In this analysis, the absolute method is used. The neutron activation technique involves irradiating the sample and subsequently performing a measurement of the activity of the sample. The fundamental equation of the activation connects several physical parameters including the cross section that is essential for the quantitative determination of the different elements composing the sample without resorting to the use of standard sample. Called the absolute method, it allows a measurement as accurate as the relative method. The results obtained by the absolute method showed that the values are as precise as the relative method requiring the use of standard sample for each element to be quantified.

  2. Sampling trace organic compounds in water: a comparison of a continuous active sampler to continuous passive and discrete sampling methods

    USGS Publications Warehouse

    Coes, Alissa L.; Paretti, Nicholas V.; Foreman, William T.; Iverson, Jana L.; Alvarez, David A.

    2014-01-01

    A continuous active sampling method was compared to continuous passive and discrete sampling methods for the sampling of trace organic compounds (TOCs) in water. Results from each method are compared and contrasted in order to provide information for future investigators to use while selecting appropriate sampling methods for their research. The continuous low-level aquatic monitoring (CLAM) sampler (C.I.Agent® Storm-Water Solutions) is a submersible, low flow-rate sampler, that continuously draws water through solid-phase extraction media. CLAM samplers were deployed at two wastewater-dominated stream field sites in conjunction with the deployment of polar organic chemical integrative samplers (POCIS) and the collection of discrete (grab) water samples. All samples were analyzed for a suite of 69 TOCs. The CLAM and POCIS samples represent time-integrated samples that accumulate the TOCs present in the water over the deployment period (19–23 h for CLAM and 29 days for POCIS); the discrete samples represent only the TOCs present in the water at the time and place of sampling. Non-metric multi-dimensional scaling and cluster analysis were used to examine patterns in both TOC detections and relative concentrations between the three sampling methods. A greater number of TOCs were detected in the CLAM samples than in corresponding discrete and POCIS samples, but TOC concentrations in the CLAM samples were significantly lower than in the discrete and (or) POCIS samples. Thirteen TOCs of varying polarity were detected by all of the three methods. TOC detections and concentrations obtained by the three sampling methods, however, are dependent on multiple factors. This study found that stream discharge, constituent loading, and compound type all affected TOC concentrations detected by each method. In addition, TOC detections and concentrations were affected by the reporting limits, bias, recovery, and performance of each method.

  3. Sampling trace organic compounds in water: a comparison of a continuous active sampler to continuous passive and discrete sampling methods.

    PubMed

    Coes, Alissa L; Paretti, Nicholas V; Foreman, William T; Iverson, Jana L; Alvarez, David A

    2014-03-01

    A continuous active sampling method was compared to continuous passive and discrete sampling methods for the sampling of trace organic compounds (TOCs) in water. Results from each method are compared and contrasted in order to provide information for future investigators to use while selecting appropriate sampling methods for their research. The continuous low-level aquatic monitoring (CLAM) sampler (C.I.Agent® Storm-Water Solutions) is a submersible, low flow-rate sampler, that continuously draws water through solid-phase extraction media. CLAM samplers were deployed at two wastewater-dominated stream field sites in conjunction with the deployment of polar organic chemical integrative samplers (POCIS) and the collection of discrete (grab) water samples. All samples were analyzed for a suite of 69 TOCs. The CLAM and POCIS samples represent time-integrated samples that accumulate the TOCs present in the water over the deployment period (19-23 h for CLAM and 29 days for POCIS); the discrete samples represent only the TOCs present in the water at the time and place of sampling. Non-metric multi-dimensional scaling and cluster analysis were used to examine patterns in both TOC detections and relative concentrations between the three sampling methods. A greater number of TOCs were detected in the CLAM samples than in corresponding discrete and POCIS samples, but TOC concentrations in the CLAM samples were significantly lower than in the discrete and (or) POCIS samples. Thirteen TOCs of varying polarity were detected by all of the three methods. TOC detections and concentrations obtained by the three sampling methods, however, are dependent on multiple factors. This study found that stream discharge, constituent loading, and compound type all affected TOC concentrations detected by each method. In addition, TOC detections and concentrations were affected by the reporting limits, bias, recovery, and performance of each method.

  4. Active Search on Carcasses versus Pitfall Traps: a Comparison of Sampling Methods.

    PubMed

    Zanetti, N I; Camina, R; Visciarelli, E C; Centeno, N D

    2016-04-01

    The study of insect succession in cadavers and the classification of arthropods have mostly been done by placing a carcass in a cage, protected from vertebrate scavengers, which is then visited periodically. An alternative is to use specific traps. Few studies on carrion ecology and forensic entomology involving the carcasses of large vertebrates have employed pitfall traps. The aims of this study were to compare both sampling methods (active search on a carcass and pitfall trapping) for each coleopteran family, and to establish whether there is a discrepancy (underestimation and/or overestimation) in the presence of each family by either method. A great discrepancy was found for almost all families with some of them being more abundant in samples obtained through active search on carcasses and others in samples from traps, whereas two families did not show any bias towards a given sampling method. The fact that families may be underestimated or overestimated by the type of sampling technique highlights the importance of combining both methods, active search on carcasses and pitfall traps, in order to obtain more complete information on decomposition, carrion habitat and cadaveric families or species. Furthermore, a hypothesis advanced on the reasons for the underestimation by either sampling method showing biases towards certain families. Information about the sampling techniques indicating which would be more appropriate to detect or find a particular family is provided.

  5. Comparison between active (pumped) and passive (diffusive) sampling methods for formaldehyde in pathology and histology laboratories

    PubMed Central

    Lee, Eun Gyung; Magrm, Rana; Kusti, Mohannad; Kashon, Michael L.; Guffey, Steven; Costas, Michelle M.; Boykin, Carie J.; Harper, Martin

    2016-01-01

    This study was to determine occupational exposures to formaldehyde and to compare concentrations of formaldehyde obtained by active and passive sampling methods. In one pathology and one histology laboratories, exposure measurements were collected with sets of active air samplers (Supelco LpDNPH tubes) and passive badges (ChemDisk Aldehyde Monitor 571). Sixty-six sample pairs (49 personal and 17 area) were collected and analyzed by NIOSH NMAM 2016 for active samples and OSHA Method 1007 (using the manufacturer’s updated uptake rate) for passive samples. All active and passive 8-hour time-weighted average (TWA) measurements showed compliance with the OSHA permissible exposure limit (PEL-0.75 ppm) except for one passive measurement, whereas 78% for the active and 88% for the passive samples exceeded the NIOSH recommended exposure limit (REL-0.016 ppm). Overall, 73% of the passive samples showed higher concentrations than the active samples and a statistical test indicated disagreement between two methods for all data and for data without outliers. The OSHA Method cautions that passive samplers should not be used for sampling situations involving formalin solutions because of low concentration estimates in the presence of reaction products of formaldehyde and methanol (a formalin additive). However, this situation was not observed, perhaps because the formalin solutions used in these laboratories included much less methanol (3%) than those tested in the OSHA Method (up to 15%). The passive samplers in general overestimated concentrations compared to the active method, which is prudent for demonstrating compliance with an occupational exposure limit, but occasional large differences may be a result of collecting aerosolized droplets or splashes on the face of the samplers. In the situations examined in this study the passive sampler generally produces higher results than the active sampler so that a body of results from passive samplers demonstrating compliance with

  6. [The activity of Codex Alimentarius Commission FAO/WHO Committee on Methods of Analysis and Sampling].

    PubMed

    Jedrzejczak, Renata; Brulińska-Ostrowska, Elzbieta; Traczyk, Iwona

    2004-01-01

    In the light of issues discussed during 24th Session of Codex Committee on Methods of Analysis and Sampling that was held in Budapest, 18-22 November 2002, the current activity of this Committee is presented. More detailed information about some of the most advanced or interesting documents is included, i. e. Proposed Draft General Guidelines On Sampling, Harmonized IUPAC Guidelines for Single-Laboratory Validation of Methods of Analysis, Consideration of methods for the detection and identification of food derived from biotechnology.

  7. A novel method for measuring aromatase activity in tissue samples by determining estradiol concentrations.

    PubMed

    Tinwell, H; Rascle, J B; Colombel, S; Al Khansa, I; Freyberger, A; Bars, R

    2011-07-01

    Increasing scrutiny of endocrine disrupters has led to changes to European pesticide and biocide legislation and to the introduction of the Endocrine Disrupter Screening Program by the US EPA. One element of endocrine disrupter identification is to determine its effects on aromatase, but most available assays are limited as they depend on tritiated water production to indicate enzyme activity. Whilst acceptable for determining aromatase effects using a cell-free approach, this method is unreliable for cell or tissue-based investigations as other cytochrome P-450 isoenzyme activities can similarly produce tritiated water and consequently confound interpretation of the aromatase data. To address this lack of specificity an assay directly measuring the final estrogen product by incubating rat tissue protein with testosterone and measuring the resultant estradiol concentration was developed. Using this approach we demonstrated marked increases in enzyme activity in pregnant rat ovary samples and dose-related inhibitions when incubating non-pregnant rat ovary samples with known aromatase inhibitors. Hepatic aromatase activity was investigated using our method and by tritiated water production with microsomes from rats dosed with the antiandrogen 1,1-dichloro-2,2-bis(4 chlorophenyl)ethane. Additional cytochrome P-450s were also measured. Treatment-related increased tritiated water production and general hepatic enzyme activity were recorded but estradiol was not increased, indicating that the increased tritiated water was due to general enzyme activity and not aromatase activity. A simple and specific method has been developed that can detect aromatase inhibition and induction, which when applied to tissue samples, provides a means of generating relevant animal data concerning chemical effects on the aromatase enzyme.

  8. Large loop conformation sampling using the activation relaxation technique, ART-nouveau method.

    PubMed

    St-Pierre, Jean-François; Mousseau, Normand

    2012-07-01

    We present an adaptation of the ART-nouveau energy surface sampling method to the problem of loop structure prediction. This method, previously used to study protein folding pathways and peptide aggregation, is well suited to the problem of sampling the conformation space of large loops by targeting probable folding pathways instead of sampling exhaustively that space. The number of sampled conformations needed by ART nouveau to find the global energy minimum for a loop was found to scale linearly with the sequence length of the loop for loops between 8 and about 20 amino acids. Considering the linear scaling dependence of the computation cost on the loop sequence length for sampling new conformations, we estimate the total computational cost of sampling larger loops to scale quadratically compared to the exponential scaling of exhaustive search methods.

  9. Sampling system and method

    DOEpatents

    Decker, David L.; Lyles, Brad F.; Purcell, Richard G.; Hershey, Ronald Lee

    2013-04-16

    The present disclosure provides an apparatus and method for coupling conduit segments together. A first pump obtains a sample and transmits it through a first conduit to a reservoir accessible by a second pump. The second pump further conducts the sample from the reservoir through a second conduit.

  10. Rapid Active Sampling Package

    NASA Technical Reports Server (NTRS)

    Peters, Gregory

    2010-01-01

    A field-deployable, battery-powered Rapid Active Sampling Package (RASP), originally designed for sampling strong materials during lunar and planetary missions, shows strong utility for terrestrial geological use. The technology is proving to be simple and effective for sampling and processing materials of strength. Although this originally was intended for planetary and lunar applications, the RASP is very useful as a powered hand tool for geologists and the mining industry to quickly sample and process rocks in the field on Earth. The RASP allows geologists to surgically acquire samples of rock for later laboratory analysis. This tool, roughly the size of a wrench, allows the user to cut away swaths of weathering rinds, revealing pristine rock surfaces for observation and subsequent sampling with the same tool. RASPing deeper (.3.5 cm) exposes single rock strata in-situ. Where a geologist fs hammer can only expose unweathered layers of rock, the RASP can do the same, and then has the added ability to capture and process samples into powder with particle sizes less than 150 microns, making it easier for XRD/XRF (x-ray diffraction/x-ray fluorescence). The tool uses a rotating rasp bit (or two counter-rotating bits) that resides inside or above the catch container. The container has an open slot to allow the bit to extend outside the container and to allow cuttings to enter and be caught. When the slot and rasp bit are in contact with a substrate, the bit is plunged into it in a matter of seconds to reach pristine rock. A user in the field may sample a rock multiple times at multiple depths in minutes, instead of having to cut out huge, heavy rock samples for transport back to a lab for analysis. Because of the speed and accuracy of the RASP, hundreds of samples can be taken in one day. RASP-acquired samples are small and easily carried. A user can characterize more area in less time than by using conventional methods. The field-deployable RASP used a Ni

  11. Determination of trace halogens in rock samples by radiochemical neutron activation analysis coupled with the k0-standardization method.

    PubMed

    Ozaki, Hiromasa; Ebihara, Mitsuru

    2007-02-05

    Radiochemical neutron activation analysis coupled with the k0-standardization method (k0-RNAA method) was applied to silicate rock samples for the simultaneous determination of trace halogens (Cl, Br and I). Analytical results obtained by the k0-RNAA method for geological standard rocks and meteorite samples agreed with those determined by the conventional comparison method conducted in the same set of experiments, suggesting that the k0-RNAA method is as reliable as the conventional method. Our data for these samples are in good agreement with their literature values except for rare cases. Detection limits calculated under the present experimental condition are sufficiently low for Cl and Br but not for I for typical geologic and meteoritic samples. The k0-RNAA method coupled with longer neutron-irradiation is expected to yield satisfactorily low detection limits for halogens including I in these samples.

  12. Monitoring airborne fungal spores in an experimental indoor environment to evaluate sampling methods and the effects of human activity on air sampling.

    PubMed Central

    Buttner, M P; Stetzenbach, L D

    1993-01-01

    Aerobiological monitoring was conducted in an experimental room to aid in the development of standardized sampling protocols for airborne microorganisms in the indoor environment. The objectives of this research were to evaluate the relative efficiencies of selected sampling methods for the retrieval of airborne fungal spores and to determine the effect of human activity on air sampling. Dry aerosols containing known concentrations of Penicillium chrysogenum spores were generated, and air samples were taken by using Andersen six-stage, Surface Air System, Burkard, and depositional samplers. The Andersen and Burkard samplers retrieved the highest numbers of spores compared with the measurement standard, an aerodynamic particle sizer located inside the room. Data from paired samplers demonstrated that the Andersen sampler had the highest levels of sensitivity and repeatability. With a carpet as the source of P. chrysogenum spores, the effects of human activity (walking or vacuuming near the sampling site) on air sampling were also examined. Air samples were taken under undisturbed conditions and after human activity in the room. Human activity resulted in retrieval of significantly higher concentrations of airborne spores. Surface sampling of the carpet revealed moderate to heavy contamination despite relatively low airborne counts. Therefore, in certain situations, air sampling without concomitant surface sampling may not adequately reflect the level of microbial contamination in indoor environments. PMID:8439150

  13. Sampling system and method

    DOEpatents

    Decker, David L.; Lyles, Brad F.; Purcell, Richard G.; Hershey, Ronald Lee

    2017-03-07

    In one embodiment, the present disclosure provides an apparatus and method for supporting a tubing bundle during installation or removal. The apparatus includes a clamp for securing the tubing bundle to an external wireline. In various examples, the clamp is external to the tubing bundle or integral with the tubing bundle. According to one method, a tubing bundle and wireline are deployed together and the tubing bundle periodically secured to the wireline using a clamp. In another embodiment, the present disclosure provides an apparatus and method for coupling conduit segments together. A first pump obtains a sample and transmits it through a first conduit to a reservoir accessible by a second pump. The second pump further conducts the sample from the reservoir through a second conduit. In a specific example, one or more clamps are used to connect the first and/or second conduits to an external wireline.

  14. Evaluation of sample preparation methods for water activity determination in jerky and kippered beef: a research note.

    PubMed

    Harper, N M; Getty, K J K; Boyle, E A E

    2010-10-01

    Commercially available packaged whole muscle beef jerky, chopped and formed beef jerky, and kippered beef steak were obtained from retail stores to determine the effect of two sample preparation methods on water activity (a(w)). Intact samples were prepared by cutting product into a hexagonal shape with a 3.2 cm diameter. Diced samples were prepared by cutting the product into 0.4 x 0.4 cm squares. Whole muscle jerky a(w) was higher (0.016 units; P<0.001) using the intact method compared to the diced method. There was no difference (P>0.05) in a(w) levels between the two preparation methods for chopped and formed jerky or kippered beef steak. An intact sample preparation method is recommended for a(w) determination of whole muscle jerky to obtain a more conservative value, especially if a(w) is near the margin of safety.

  15. Porous membrane ultrafiltration-A novel method for enrichment of the active compounds from micro-plasma samples

    NASA Astrophysics Data System (ADS)

    Liu, Qingshan; Yin, Xiaoying; Sha, Biying; You, Jingjing

    2014-10-01

    To enrich the active compounds from plasma samples, a novel and simple method has been developed using a porous membrane envelope based on the ultrafiltration technique combining with high-performance liquid chromatography. The ultrafiltration device is a sealed porous membrane envelope prepared with a polypropylene sheet to effectively separate the active small molecules and large biomolecules, and a sample carrier is held inside the envelope to load plasma samples. The enrichment of hyperoside and isoquercitrin from rat plasma was used as an example. Significant factors of this method, such as membrane types, the desorption solvent, and the desorption time were optimized for the ultrafiltration method. Under the optimal conditions, correlation coefficients of 0.999 and 0.998 were obtained for hyperoside and isoquercitrin, respectively, with a linear range between 0.5 and 100 μg/mL. The absolute extraction recoveries from 83.2% to 86.8% were achieved. The detection limits of the method for hyperoside and isoquercitrin were 0.22 and 0.20 μg/mL, respectively. Compared with protein precipitation, solid-phase extraction and commercial ultrafiltration membrane methods, our proposed method demonstrates lower detection limits and lower cost for extraction. Also, it consumes less plasma samples and is found to be applicable to biological samples.

  16. Porous membrane ultrafiltration-A novel method for enrichment of the active compounds from micro-plasma samples.

    PubMed

    Liu, Qingshan; Yin, Xiaoying; Sha, Biying; You, Jingjing

    2014-10-15

    To enrich the active compounds from plasma samples, a novel and simple method has been developed using a porous membrane envelope based on the ultrafiltration technique combining with high-performance liquid chromatography. The ultrafiltration device is a sealed porous membrane envelope prepared with a polypropylene sheet to effectively separate the active small molecules and large biomolecules, and a sample carrier is held inside the envelope to load plasma samples. The enrichment of hyperoside and isoquercitrin from rat plasma was used as an example. Significant factors of this method, such as membrane types, the desorption solvent, and the desorption time were optimized for the ultrafiltration method. Under the optimal conditions, correlation coefficients of 0.999 and 0.998 were obtained for hyperoside and isoquercitrin, respectively, with a linear range between 0.5 and 100μg/mL. The absolute extraction recoveries from 83.2% to 86.8% were achieved. The detection limits of the method for hyperoside and isoquercitrin were 0.22 and 0.20μg/mL, respectively. Compared with protein precipitation, solid-phase extraction and commercial ultrafiltration membrane methods, our proposed method demonstrates lower detection limits and lower cost for extraction. Also, it consumes less plasma samples and is found to be applicable to biological samples.

  17. Azocasein Substrate for Determination of Proteolytic Activity: Reexamining a Traditional Method Using Bromelain Samples.

    PubMed

    Coêlho, Diego F; Saturnino, Thais Peron; Fernandes, Fernanda Freitas; Mazzola, Priscila Gava; Silveira, Edgar; Tambourgi, Elias Basile

    2016-01-01

    Given the importance of protease's worldwide market, the determination of optimum conditions and the development of a standard protocol are critical during selection of a reliable method to determine its bioactivity. This paper uses quality control theory to validate a modified version of a method proposed by Charney and Tomarelli in 1947. The results obtained showed that using azocasein substrate bromelain had its optimum at 45°C and pH 9 (Glycine-NaOH 100 mM). We also quantified the limit of detection (LoD) and limit of quantification (LoQ) in the above-mentioned optimum (0.072 and 0.494 mg·mL(-1) of azocasein, resp.) and a calibration curve that correlates optical density with the amount of substrate digested. In all analysed samples, we observed a significant decrease in response after storage (around 17%), which suggests its use must be immediately after preparation. Thus, the protocol presented in this paper offers a significant improvement, given that subjective definitions are commonly used in the literature and this simple mathematical approach makes it clear and concise.

  18. Azocasein Substrate for Determination of Proteolytic Activity: Reexamining a Traditional Method Using Bromelain Samples

    PubMed Central

    Mazzola, Priscila Gava

    2016-01-01

    Given the importance of protease's worldwide market, the determination of optimum conditions and the development of a standard protocol are critical during selection of a reliable method to determine its bioactivity. This paper uses quality control theory to validate a modified version of a method proposed by Charney and Tomarelli in 1947. The results obtained showed that using azocasein substrate bromelain had its optimum at 45°C and pH 9 (Glycine-NaOH 100 mM). We also quantified the limit of detection (LoD) and limit of quantification (LoQ) in the above-mentioned optimum (0.072 and 0.494 mg·mL−1 of azocasein, resp.) and a calibration curve that correlates optical density with the amount of substrate digested. In all analysed samples, we observed a significant decrease in response after storage (around 17%), which suggests its use must be immediately after preparation. Thus, the protocol presented in this paper offers a significant improvement, given that subjective definitions are commonly used in the literature and this simple mathematical approach makes it clear and concise. PMID:26925415

  19. Field trial of applicability of lot quality assurance sampling survey method for rapid assessment of prevalence of active trachoma.

    PubMed Central

    Myatt, Mark; Limburg, Hans; Minassian, Darwin; Katyola, Damson

    2003-01-01

    OBJECTIVE: To test the applicability of lot quality assurance sampling (LQAS) for the rapid assessment of the prevalence of active trachoma. METHODS: Prevalence of active trachoma in six communities was found by examining all children aged 2-5 years. Trial surveys were conducted in these communities. A sampling plan appropriate for classifying communities with prevalences < or =20% and > or =40% was applied to the survey data. Operating characteristic and average sample number curves were plotted, and screening test indices were calculated. The ability of LQAS to provide a three-class classification system was investigated. FINDINGS: Ninety-six trial surveys were conducted. All communities with prevalences < or =20% and > or =40% were identified correctly. The method discriminated between communities with prevalences < or =30% and >30%, with sensitivity of 98% (95% confidence interval (CI)=88.2-99.9%), specificity of 84.4% (CI=69.9-93.0%), positive predictive value of 87.7% (CI=75.7-94.5%), negative predictive value of 97.4% (CI=84.9-99.9%), and accuracy of 91.7% (CI=83.8-96.1%). Agreement between the three prevalence classes and survey classifications was 84.4% (CI=75.2-90.7%). The time needed to complete the surveys was consistent with the need to complete a survey in one day. CONCLUSION: Lot quality assurance sampling provides a method of classifying communities according to the prevalence of active trachoma. It merits serious consideration as a replacement for the assessment of the prevalence of active trachoma with the currently used trachoma rapid assessment method. It may be extended to provide a multi-class classification method. PMID:14997240

  20. Improved Sampling Method Reduces Isokinetic Sampling Errors.

    ERIC Educational Resources Information Center

    Karels, Gale G.

    The particulate sampling system currently in use by the Bay Area Air Pollution Control District, San Francisco, California is described in this presentation for the 12th Conference on Methods in Air Pollution and Industrial Hygiene Studies, University of Southern California, April, 1971. The method represents a practical, inexpensive tool that can…

  1. Sample preparation method for the ER-CALUX bioassay screening of (xeno-)estrogenic activity in sediment extracts.

    PubMed

    Houtman, Corine J; Leonards, Pim E G; Kapiteijn, Wendy; Bakker, Joop F; Brouwer, Abraham; Lamoree, Marja H; Legler, Juliette; Klamer, Hans J C

    2007-11-01

    The application of bioassays to assess the occurrence of estrogenic compounds in the environment is increasing in both a scientific and statutory context. The availability of appropriate validated methods for sample pre-treatment and analysis is crucial for the successful implementation of bioassays. Here, we present a sample preparation method for the bioassay screening of estrogenic activity in sediment with the in vitro Estrogen Receptor mediated Chemical Activated LUciferase gene eXpression (ER-CALUX) assay. The method makes use of an Accelerated Solvent (ASE) or Soxhlet extraction with a mixture of dichloromethane and acetone (3:1, v/v), followed by clean up of the extract by Gel Permeation Chromatography (GPC). Recoveries of a panel of 17 pollutants differing largely in physical-chemical properties from spiked sediment were determined and appeared to be on average about 86%. Furthermore, the estrogenic potencies of all test compounds were individually assessed by determination of concentration-response relationships in the ER-CALUX assay. Concentration dependent estrogenic potency was found for 14 of the 17 compounds, with potencies of about 10(5) to 10(7) fold lower than the natural estrogenic hormone 17beta-estradiol. Anti-estrogenic potency was assessed by testing combinations of estradiol and individual test compounds, but was found for none of the compounds. The low estrogenic activity of the test compounds in the spiking mixture was well recovered during GPC treatment of the pure mixture, but did not contribute significantly to the background estrogenic activity present in the spiked sediment. Application of the method to field samples showed that estrogenic activity can be found at different types of locations, and demonstrated that levels between locations may vary considerably over relatively short distances.

  2. Final Project Report for the Development of an Active Soil Gas Sampling Method

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the nation's natural resources. Under the mandate of national environmental laws, the EPA strives to formulate and implement actions leading to a compatible balance between human activities and ...

  3. Sampling system and method

    SciTech Connect

    Decker, David L; Lyles, Brad F; Purcell, Richard G; Hershey, Ronald Lee

    2014-05-20

    An apparatus and method for supporting a tubing bundle during installation or removal. The apparatus includes a clamp for securing the tubing bundle to an external wireline. The method includes deploying the tubing bundle and wireline together, The tubing bundle is periodically secured to the wireline using a clamp.

  4. Elaborating transition interface sampling methods

    SciTech Connect

    Erp, Titus S. van . E-mail: bolhuis@science.uva.nl

    2005-05-01

    We review two recently developed efficient methods for calculating rate constants of processes dominated by rare events in high-dimensional complex systems. The first is transition interface sampling (TIS), based on the measurement of effective fluxes through hypersurfaces in phase space. TIS improves efficiency with respect to standard transition path sampling (TPS) rate constant techniques, because it allows a variable path length and is less sensitive to recrossings. The second method is the partial path version of TIS. Developed for diffusive processes, it exploits the loss of long time correlation. We discuss the relation between the new techniques and the standard reactive flux methods in detail. Path sampling algorithms can suffer from ergodicity problems, and we introduce several new techniques to alleviate these problems, notably path swapping, stochastic configurational bias Monte Carlo shooting moves and order-parameter free path sampling. In addition, we give algorithms to calculate other interesting properties from path ensembles besides rate constants, such as activation energies and reaction mechanisms.

  5. A New Method for Determining Residues Generated during Munition Demilitarization Activities: Analysis of Environmental Soil and Water Samples

    DTIC Science & Technology

    1991-04-18

    High Performance Liquid Chromatography (HPLC) gradient method was developed, and used to screen samples for a wide range of munitions and PAHs. Quantitation of munitions and their environmental reduction products was accomplished using an HPLC isocratic method. Recoveries of munitions and degradation products spiked into sandy loam soils were greater than 90% in all cases. Corresponding recoveries from aqueous samples were comparable for the nitroaromatics, but were poorer for the

  6. Active submarine volcano sampled

    USGS Publications Warehouse

    Taylor, B.

    1983-01-01

    On June 4, 1982, two full dredge hauls of fresh lava were recovered from the upper flanks of Kavachi submarine volcano, Solomon Islands, in the western Pacific Ocean, from the water depths of 1,200 and 2,700 feet. the shallower dredge site was within 0.5 mile of the active submarine vent shown at the surface by an area of slick water, probably caused by gas emissions. Kavachi is a composite stratovolcano that has been observed to erupt every year or two for at least the last 30 years (see photographs). An island formed in 1952, 1961, 1965, and 1978; but, in each case, it rapidly eroded below sea level. The latest eruption was observed by Solair pilots during the several weeks up to and including May 18, 1982. 

  7. Duplex sampling apparatus and method

    DOEpatents

    Brown, Paul E.; Lloyd, Robert

    1992-01-01

    An improved apparatus is provided for sampling a gaseous mixture and for measuring mixture components. The apparatus includes two sampling containers connected in series serving as a duplex sampling apparatus. The apparatus is adapted to independently determine the amounts of condensable and noncondensable gases in admixture from a single sample. More specifically, a first container includes a first port capable of selectively connecting to and disconnecting from a sample source and a second port capable of selectively connecting to and disconnecting from a second container. A second container also includes a first port capable of selectively connecting to and disconnecting from the second port of the first container and a second port capable of either selectively connecting to and disconnecting from a differential pressure source. By cooling a mixture sample in the first container, the condensable vapors form a liquid, leaving noncondensable gases either as free gases or dissolved in the liquid. The condensed liquid is heated to drive out dissolved noncondensable gases, and all the noncondensable gases are transferred to the second container. Then the first and second containers are separated from one another in order to separately determine the amount of noncondensable gases and the amount of condensable gases in the sample.

  8. A novel near-infrared spectroscopy and chemometrics method for rapid analysis of several chemical components and antioxidant activity of mint (Mentha haplocalyx Briq.) samples.

    PubMed

    Dong, Wenjiang; Ni, Yongnian; Kokot, Serge

    2014-01-01

    A novel near-infrared spectroscopy (NIRS) method has been researched and developed for the simultaneous analyses of the chemical components and associated properties of mint (Mentha haplocalyx Briq.) tea samples. The common analytes were: total polysaccharide content, total flavonoid content, total phenolic content, and total antioxidant activity. To resolve the NIRS data matrix for such analyses, least squares support vector machines was found to be the best chemometrics method for prediction, although it was closely followed by the radial basis function/partial least squares model. Interestingly, the commonly used partial least squares was unsatisfactory in this case. Additionally, principal component analysis and hierarchical cluster analysis were able to distinguish the mint samples according to their four geographical provinces of origin, and this was further facilitated with the use of the chemometrics classification methods-K-nearest neighbors, linear discriminant analysis, and partial least squares discriminant analysis. In general, given the potential savings with sampling and analysis time as well as with the costs of special analytical reagents required for the standard individual methods, NIRS offered a very attractive alternative for the simultaneous analysis of mint samples.

  9. Well purge and sample apparatus and method

    DOEpatents

    Schalla, Ronald; Smith, Ronald M.; Hall, Stephen H.; Smart, John E.; Gustafson, Gregg S.

    1995-01-01

    The present invention specifically permits purging and/or sampling of a well but only removing, at most, about 25% of the fluid volume compared to conventional methods and, at a minimum, removing none of the fluid volume from the well. The invention is an isolation assembly with a packer, pump and exhaust, that is inserted into the well. The isolation assembly is designed so that only a volume of fluid between the outside diameter of the isolation assembly and the inside diameter of the well over a fluid column height from the bottom of the well to the top of the active portion (lower annulus) is removed. The packer is positioned above the active portion thereby sealing the well and preventing any mixing or contamination of inlet fluid with fluid above the packer. Ports in the wall of the isolation assembly permit purging and sampling of the lower annulus along the height of the active portion.

  10. Well purge and sample apparatus and method

    DOEpatents

    Schalla, R.; Smith, R.M.; Hall, S.H.; Smart, J.E.; Gustafson, G.S.

    1995-10-24

    The present invention specifically permits purging and/or sampling of a well but only removing, at most, about 25% of the fluid volume compared to conventional methods and, at a minimum, removing none of the fluid volume from the well. The invention is an isolation assembly with a packer, pump and exhaust, that is inserted into the well. The isolation assembly is designed so that only a volume of fluid between the outside diameter of the isolation assembly and the inside diameter of the well over a fluid column height from the bottom of the well to the top of the active portion (lower annulus) is removed. The packer is positioned above the active portion thereby sealing the well and preventing any mixing or contamination of inlet fluid with fluid above the packer. Ports in the wall of the isolation assembly permit purging and sampling of the lower annulus along the height of the active portion. 8 figs.

  11. Apparatus and method for handheld sampling

    DOEpatents

    Staab, Torsten A.

    2005-09-20

    The present invention includes an apparatus, and corresponding method, for taking a sample. The apparatus is built around a frame designed to be held in at least one hand. A sample media is used to secure the sample. A sample media adapter for securing the sample media is operated by a trigger mechanism connectively attached within the frame to the sample media adapter.

  12. Soil sampling kit and a method of sampling therewith

    DOEpatents

    Thompson, C.V.

    1991-02-05

    A soil sampling device and a sample containment device for containing a soil sample is disclosed. In addition, a method for taking a soil sample using the soil sampling device and soil sample containment device to minimize the loss of any volatile organic compounds contained in the soil sample prior to analysis is disclosed. The soil sampling device comprises two close fitting, longitudinal tubular members of suitable length, the inner tube having the outward end closed. With the inner closed tube withdrawn a selected distance, the outer tube can be inserted into the ground or other similar soft material to withdraw a sample of material for examination. The inner closed end tube controls the volume of the sample taken and also serves to eject the sample. The soil sample containment device has a sealing member which is adapted to attach to an analytical apparatus which analyzes the volatile organic compounds contained in the sample. The soil sampling device in combination with the soil sample containment device allows an operator to obtain a soil sample containing volatile organic compounds and minimizing the loss of the volatile organic compounds prior to analysis of the soil sample for the volatile organic compounds. 11 figures.

  13. Soil sampling kit and a method of sampling therewith

    DOEpatents

    Thompson, Cyril V.

    1991-01-01

    A soil sampling device and a sample containment device for containing a soil sample is disclosed. In addition, a method for taking a soil sample using the soil sampling device and soil sample containment device to minimize the loss of any volatile organic compounds contained in the soil sample prior to analysis is disclosed. The soil sampling device comprises two close fitting, longitudinal tubular members of suitable length, the inner tube having the outward end closed. With the inner closed tube withdrawn a selected distance, the outer tube can be inserted into the ground or other similar soft material to withdraw a sample of material for examination. The inner closed end tube controls the volume of the sample taken and also serves to eject the sample. The soil sample containment device has a sealing member which is adapted to attach to an analytical apparatus which analyzes the volatile organic compounds contained in the sample. The soil sampling device in combination with the soil sample containment device allow an operator to obtain a soil sample containing volatile organic compounds and minimizing the loss of the volatile organic compounds prior to analysis of the soil sample for the volatile organic compounds.

  14. Quantifying Isoniazid Levels in Small Hair Samples: A Novel Method for Assessing Adherence during the Treatment of Latent and Active Tuberculosis

    PubMed Central

    Gerona, Roy; Wen, Anita; Chin, Aaron T.; Koss, Catherine A.; Bacchetti, Peter; Metcalfe, John; Gandhi, Monica

    2016-01-01

    Background Tuberculosis (TB) is the leading cause of death from an infectious pathogen worldwide and the most prevalent opportunistic infection in people living with HIV. Isoniazid preventive therapy (IPT) reduces the incidence of active TB and reduces morbidity and mortality in HIV-infected patients independently of antiretroviral therapy. However, treatment of latent or active TB is lengthy and inter-patient variability in pharmacokinetics and adherence common. Current methods of assessing adherence to TB treatment using drug levels in plasma or urine assess short-term exposure and pose logistical challenges. Drug concentrations in hair assess long-term exposure and have demonstrated pharmacodynamic relevance in HIV. Methods A large hair sample from a patient with active TB was obtained for assay development. Methods to pulverize hair and extract isoniazid were optimized and then the drug detected by liquid chromatography/ tandem mass spectrometry (LC/MS-MS). The method was validated for specificity, accuracy, precision, recovery, linearity and stability to establish the assay’s suitability for therapeutic drug monitoring (TDM). Hair samples from patients on directly-observe isoniazid-based latent or active TB therapy from the San Francisco Department of Public Health TB clinic were then tested. Results Our LC/MS-MS-based assay detected isoniazid in quantities as low as 0.02ng/mg using 10–25 strands hair. Concentrations in spiked samples demonstrated linearity from 0.05–50ng/mg. Assay precision and accuracy for spiked quality-control samples were high, with an overall recovery rate of 79.5%. In 18 patients with latent or active TB on treatment, isoniazid was detected across a wide linear dynamic range. Conclusions An LC-MS/MS-based assay to quantify isoniazid levels in hair with performance characteristics suitable for TDM was developed and validated. Hair concentrations of isoniazid assess long-term exposure and may be useful for monitoring adherence to

  15. Biological validation of a sample preparation method for ER-CALUX bioanalysis of estrogenic activity in sediment using mixtures of xeno-estrogens.

    PubMed

    Houtman, Corine J; Van Houten, Yoni K; Leonards, Pim E G; Brouwer, Abraham; Lamoree, Marja H; Legler, Juliette

    2006-04-01

    The combined estrogenic effects of mixtures of environmental pollutants in the in vitro ER-CALUX (chemical activated luciferase gene expression) bioassaywere examined to biologically validate a sample preparation method for the analysis of estrogenic compounds in sediment. The method used accelerated solvent extraction (ASE) and gel permeation chromatography (GPC) and was validated with respect to recovery of biological response taking mixture effects into account. Four mixtures of three to six xenoestrogenic compounds (bisphenol A, 4-nonylphenol, (4,4'-dichlorodiphenyl)trichloroethane, (2,4'-dichlorodiphenyl)trichloroethane, dieldrin, 4-n-octylphenol, alpha-chlordane, dibutylphthalate, (4,4'-dichlorodiphenyl)dichloroethylene, and 2,4,5-trichlorobiphenyl) were prepared. Experimentally determined mixture effects were well described by the concept of concentration addition (CA), as expected for similarly acting compounds. Observed estradiol equivalence factors of the mixtures (on average 1.2 +/- 0.3) agreed very well with the value predicted according to CA. The sample preparation method was then applied to pure mixtures of standards and to sediment spiked with one of the mixtures. Recoveries of estrogenic compounds were estimated by determination of their mixture potencies in ER-CALUX and compared to the mixture effects predicted by CA. Recoveries of estrogenic activity were between 80 and 129%, indicating that the additive behavior of mixtures of xeno-estrogens is well conserved during sample preparation. Together with an average repeatability of 18.3%, low average limit of detection (2.6 +/- 1.8 pg of EEQ/ g), and coefficient of variance (3.5 +/- 3.3%),this demonstrated the suitability of the sample preparation method for the analysis of mixtures of (xeno-)estrogenic compounds in sediment with the ER-CALUX assay.

  16. Characterization of Soil Samples of Enzyme Activity

    ERIC Educational Resources Information Center

    Freeland, P. W.

    1977-01-01

    Described are nine enzyme essays for distinguishing soil samples. Colorimetric methods are used to compare enzyme levels in soils from different sites. Each soil tested had its own spectrum of activity. Attention is drawn to applications of this technique in forensic science and in studies of soil fertility. (Author/AJ)

  17. Non-destructive elemental analysis of large meteorite samples by prompt gamma-ray neutron activation analysis with the internal mono-standard method.

    PubMed

    Latif, Sk A; Oura, Y; Ebihara, M; Nakahara, H

    2013-11-01

    Prompt gamma-ray neutron activation analysis (PGNAA) using the internal mono-standard method was tested for its applicability to analyzing large solid samples including irregularly shaped meteorite samples. For evaluating the accuracy and precision of the method, large quantities of the Geological Survey of Japan standardized rock powders (JB-1a, JG-1a, and JP-1) were analyzed and 12 elements (B, Na, Mg, Al, Cl, K, Ca, Ti, Mn, Fe, Sm, and Gd) were determined by using Si as an internal standard element. Analytical results were mostly in agreement with literature values within 10 %. The precision of the method was also shown to be within 10 % (1σ) for most of these elements. The analytical procedure was then applied to four stony meteorites (Allende, Kimble County, Leedey, Lake Labyrinth) and four iron meteorites (Canyon Diablo, Toluca (Mexico), Toluca (Xiquipilco), Squaw Creek) consisting of large chunks or single slabs. For stony meteorites, major elements (Mg, Al, Si, S, Ca, and Ni), minor elements (Na and Mn) and trace element (B, Cl, K, Ti, Co, and Sm) were determined with adequate accuracy. For iron meteorites, results for the Co and Ni mass fractions determined are all consistent with corresponding literature values. After the analysis, it was confirmed that the residual radioactivity remaining in the sample after PGNAA was very low and decreased down to the background level. This study shows that PGNAA with the internal mono-standard method is highly practical for determining the elemental composition of large, irregularly shaped solid samples including meteorites.

  18. Subrandom methods for multidimensional nonuniform sampling

    NASA Astrophysics Data System (ADS)

    Worley, Bradley

    2016-08-01

    Methods of nonuniform sampling that utilize pseudorandom number sequences to select points from a weighted Nyquist grid are commonplace in biomolecular NMR studies, due to the beneficial incoherence introduced by pseudorandom sampling. However, these methods require the specification of a non-arbitrary seed number in order to initialize a pseudorandom number generator. Because the performance of pseudorandom sampling schedules can substantially vary based on seed number, this can complicate the task of routine data collection. Approaches such as jittered sampling and stochastic gap sampling are effective at reducing random seed dependence of nonuniform sampling schedules, but still require the specification of a seed number. This work formalizes the use of subrandom number sequences in nonuniform sampling as a means of seed-independent sampling, and compares the performance of three subrandom methods to their pseudorandom counterparts using commonly applied schedule performance metrics. Reconstruction results using experimental datasets are also provided to validate claims made using these performance metrics.

  19. Method and apparatus for data sampling

    DOEpatents

    Odell, D.M.C.

    1994-04-19

    A method and apparatus for sampling radiation detector outputs and determining event data from the collected samples is described. The method uses high speed sampling of the detector output, the conversion of the samples to digital values, and the discrimination of the digital values so that digital values representing detected events are determined. The high speed sampling and digital conversion is performed by an A/D sampler that samples the detector output at a rate high enough to produce numerous digital samples for each detected event. The digital discrimination identifies those digital samples that are not representative of detected events. The sampling and discrimination also provides for temporary or permanent storage, either serially or in parallel, to a digital storage medium. 6 figures.

  20. Method and apparatus for data sampling

    DOEpatents

    Odell, Daniel M. C.

    1994-01-01

    A method and apparatus for sampling radiation detector outputs and determining event data from the collected samples. The method uses high speed sampling of the detector output, the conversion of the samples to digital values, and the discrimination of the digital values so that digital values representing detected events are determined. The high speed sampling and digital conversion is performed by an A/D sampler that samples the detector output at a rate high enough to produce numerous digital samples for each detected event. The digital discrimination identifies those digital samples that are not representative of detected events. The sampling and discrimination also provides for temporary or permanent storage, either serially or in parallel, to a digital storage medium.

  1. Mixed Methods Sampling: A Typology with Examples

    ERIC Educational Resources Information Center

    Teddlie, Charles; Yu, Fen

    2007-01-01

    This article presents a discussion of mixed methods (MM) sampling techniques. MM sampling involves combining well-established qualitative and quantitative techniques in creative ways to answer research questions posed by MM research designs. Several issues germane to MM sampling are presented including the differences between probability and…

  2. ALARA ASSESSMENT OF SETTLER SLUDGE SAMPLING METHODS

    SciTech Connect

    NELSEN LA

    2009-01-30

    The purpose of this assessment is to compare underwater and above water settler sludge sampling methods to determine if the added cost for underwater sampling for the sole purpose of worker dose reductions is justified. Initial planning for sludge sampling included container, settler and knock-out-pot (KOP) sampling. Due to the significantly higher dose consequence of KOP sludge, a decision was made to sample KOP underwater to achieve worker dose reductions. Additionally, initial plans were to utilize the underwater sampling apparatus for settler sludge. Since there are no longer plans to sample KOP sludge, the decision for underwater sampling for settler sludge needs to be revisited. The present sampling plan calls for spending an estimated $2,500,000 to design and construct a new underwater sampling system (per A21 C-PL-001 RevOE). This evaluation will compare and contrast the present method of above water sampling to the underwater method that is planned by the Sludge Treatment Project (STP) and determine if settler samples can be taken using the existing sampling cart (with potentially minor modifications) while maintaining doses to workers As Low As Reasonably Achievable (ALARA) and eliminate the need for costly redesigns, testing and personnel retraining.

  3. Uniform sampling table method and its applications: establishment of a uniform sampling method.

    PubMed

    Chen, Yibin; Chen, Jiaxi; Wang, Wei

    2013-01-01

    A novel uniform sampling method is proposed in this paper. According to the requirements of uniform sampling, we propose the properties that must be met by analyzing the distribution of samples. Based on this, the proposed uniform sampling method is demonstrated and evaluated strictly by mathematical means such as inference. The uniform sampling tables with respect to Cn(t2) and Cn(t3) are established. Furthermore, a one-dimension uniform sampling method and a multidimension method are proposed. The proposed novel uniform sampling method, which is guided by uniform design theory, enjoys the advantages of simplified use and good representativeness of the whole sample.

  4. A LITERATURE REVIEW OF WIPE SAMPLING METHODS ...

    EPA Pesticide Factsheets

    Wipe sampling is an important technique for the estimation of contaminant deposition in buildings, homes, or outdoor surfaces as a source of possible human exposure. Numerousmethods of wipe sampling exist, and each method has its own specification for the type of wipe, wetting solvent, and determinative step to be used, depending upon the contaminant of concern. The objective of this report is to concisely summarize the findings of a literature review that was conducted to identify the state-of-the-art wipe sampling techniques for a target list of compounds. This report describes the methods used to perform the literature review; a brief review of wipe sampling techniques in general; an analysis of physical and chemical properties of each target analyte; an analysis of wipe sampling techniques for the target analyte list; and asummary of the wipe sampling techniques for the target analyte list, including existing data gaps. In general, no overwhelming consensus can be drawn from the current literature on how to collect a wipe sample for the chemical warfare agents, organophosphate pesticides, and other toxic industrial chemicals of interest to this study. Different methods, media, and wetting solvents have been recommended and used by various groups and different studies. For many of the compounds of interest, no specific wipe sampling methodology has been established for their collection. Before a wipe sampling method (or methods) can be established for the co

  5. Determination of selected cardiovascular active compounds in environmental aquatic samples--Methods and results, a review of global publications from the last 10 years.

    PubMed

    Stankiewicz, Albert; Giebułtowicz, Joanna; Stankiewicz, Urszula; Wroczyński, Piotr; Nałęcz-Jawecki, Grzegorz

    2015-11-01

    In recent years cardiovascular diseases were the second most common cause of death worldwide. Therefore, the consumption of cardiovascular drugs is high, which might result in an increase of them in the environment. The major source of aquatic environmental contamination is still effluents of wastewater treatment plants (WWTPs). Unfortunately removal of cardiovascular active compounds and/or their metabolites in WWTP is still unsatisfactory. Among microbial and abiotic degradation of these compounds during wastewater processes, photolysis and photodegradation of cardiovascular drugs also play an important role. New formed compounds may be more toxic or retain the properties of parent compounds. Thus the main goal of this paper was to provide a detailed and comprehensive review of used analytical methods, coupled to liquid chromatography-tandem mass spectrometry, to determine the presence of cardiovascular compounds in surface waters as well as WTTPs effluents and influents. Exhaustive preparation for mass spectrometry detection and quantitation including samples pre-treatment, and the common problem of the matrix effect are thoroughly explored in this paper. Additionally, the article provides some hints in respect of recently noted problematic issue related to the availability of specific standards for the analysis of drug's metabolites. Furthermore, information concerning the metabolism of cardiovascular active compounds including differences in metabolism within enantiomers is described. This article also touches on the problems associated with environmental risk assessment due to the presence of cardiovasculars in the environment. The paper also tries to explain differences in concentrations among cardiovascular compounds between countries worldwide.

  6. Dynamic Method for Identifying Collected Sample Mass

    NASA Technical Reports Server (NTRS)

    Carson, John

    2008-01-01

    G-Sample is designed for sample collection missions to identify the presence and quantity of sample material gathered by spacecraft equipped with end effectors. The software method uses a maximum-likelihood estimator to identify the collected sample's mass based on onboard force-sensor measurements, thruster firings, and a dynamics model of the spacecraft. This makes sample mass identification a computation rather than a process requiring additional hardware. Simulation examples of G-Sample are provided for spacecraft model configurations with a sample collection device mounted on the end of an extended boom. In the absence of thrust knowledge errors, the results indicate that G-Sample can identify the amount of collected sample mass to within 10 grams (with 95-percent confidence) by using a force sensor with a noise and quantization floor of 50 micrometers. These results hold even in the presence of realistic parametric uncertainty in actual spacecraft inertia, center-of-mass offset, and first flexibility modes. Thrust profile knowledge is shown to be a dominant sensitivity for G-Sample, entering in a nearly one-to-one relationship with the final mass estimation error. This means thrust profiles should be well characterized with onboard accelerometers prior to sample collection. An overall sample-mass estimation error budget has been developed to approximate the effect of model uncertainty, sensor noise, data rate, and thrust profile error on the expected estimate of collected sample mass.

  7. Innovative methods for inorganic sample preparation

    SciTech Connect

    Essling, A.M.; Huff, E.A.; Graczyk, D.G.

    1992-04-01

    Procedures and guidelines are given for the dissolution of a variety of selected materials using fusion, microwave, and Parr bomb techniques. These materials include germanium glass, corium-concrete mixtures, and zeolites. Emphasis is placed on sample-preparation approaches that produce a single master solution suitable for complete multielement characterization of the sample. In addition, data are presented on the soil microwave digestion method approved by the Environmental Protection Agency (EPA). Advantages and disadvantages of each sample-preparation technique are summarized.

  8. Method and apparatus for sampling atmospheric mercury

    DOEpatents

    Trujillo, Patricio E.; Campbell, Evan E.; Eutsler, Bernard C.

    1976-01-20

    A method of simultaneously sampling particulate mercury, organic mercurial vapors, and metallic mercury vapor in the working and occupational environment and determining the amount of mercury derived from each such source in the sampled air. A known volume of air is passed through a sampling tube containing a filter for particulate mercury collection, a first adsorber for the selective adsorption of organic mercurial vapors, and a second adsorber for the adsorption of metallic mercury vapor. Carbon black molecular sieves are particularly useful as the selective adsorber for organic mercurial vapors. The amount of mercury adsorbed or collected in each section of the sampling tube is readily quantitatively determined by flameless atomic absorption spectrophotometry.

  9. The rank product method with two samples.

    PubMed

    Koziol, James A

    2010-11-05

    Breitling et al. (2004) introduced a statistical technique, the rank product method, for detecting differentially regulated genes in replicated microarray experiments. The technique has achieved widespread acceptance and is now used more broadly, in such diverse fields as RNAi analysis, proteomics, and machine learning. In this note, we extend the rank product method to the two sample setting, provide distribution theory attending the rank product method in this setting, and give numerical details for implementing the method.

  10. DOE methods for evaluating environmental and waste management samples.

    SciTech Connect

    Goheen, S C; McCulloch, M; Thomas, B L; Riley, R G; Sklarew, D S; Mong, G M; Fadeff, S K

    1994-04-01

    DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) provides applicable methods in use by. the US Department of Energy (DOE) laboratories for sampling and analyzing constituents of waste and environmental samples. The development of DOE Methods is supported by the Laboratory Management Division (LMD) of the DOE. This document contains chapters and methods that are proposed for use in evaluating components of DOE environmental and waste management samples. DOE Methods is a resource intended to support sampling and analytical activities that will aid in defining the type and breadth of contamination and thus determine the extent of environmental restoration or waste management actions needed, as defined by the DOE, the US Environmental Protection Agency (EPA), or others.

  11. Apparatus and method for time-integrated, active sampling of contaminants in fluids demonstrated by monitoring of hexavalent chromium in groundwater.

    PubMed

    Roll, Isaac B; Driver, Erin M; Halden, Rolf U

    2016-06-15

    Annual U.S. expenditures of $2B for site characterization invite the development of new technologies to improve data quality while reducing costs and minimizing uncertainty in groundwater monitoring. This work presents a new instrument for time-integrated sampling of environmental fluids using in situ solid-phase extraction (SPE). The In Situ Sampler (IS2) is an automated submersible device capable of extracting dissolved contaminants from water (100s-1000smL) over extended periods (hours to weeks), retaining the analytes, and rejecting the processed fluid. A field demonstration of the IS2 revealed 28-day average concentration of hexavalent chromium in a shallow aquifer affected by tidal stresses via sampling of groundwater as both liquid and sorbed composite samples, each obtained in triplicate. In situ SPE exhibited 75±6% recovery and an 8-fold improvement in reporting limit. Relative to use of conventional methods (100%), beneficial characteristics of the device and method included minimal hazardous material generation (2%), transportation cost (10%), and associated carbon footprint (2%). The IS2 is compatible with commercial SPE resins and standard extraction methods, and has been certified for more general use (i.e., inorganics and organics) by the Environmental Security Technology Certification Program (ESTCP) of the U.S. Department of Defense.

  12. Actinide recovery method -- Large soil samples

    SciTech Connect

    Maxwell , S.L. III

    2000-04-25

    There is a need to measure actinides in environmental samples with lower and lower detection limits, requiring larger sample sizes. This analysis is adversely affected by sample-matrix interferences, which make analyzing soil samples above five-grams very difficult. A new Actinide-Recovery Method has been developed by the Savannah River Site Central Laboratory to preconcentrate actinides from large-soil samples. Diphonix Resin (Eichrom Industries), a 1994 R and D 100 winner, is used to preconcentrate the actinides from large soil samples, which are bound powerfully to the resin's diphosphonic acid groups. A rapid microwave-digestion technique is used to remove the actinides from the Diphonix Resin, which effectively eliminates interfering matrix components from the soil matrix. The microwave-digestion technique is more effective and less tedious than catalyzed hydrogen peroxide digestions of the resin or digestion of diphosphonic stripping agents such as HEDPA. After resin digestion, the actinides are recovered in a small volume of nitric acid which can be loaded onto small extraction chromatography columns, such as TEVA Resin, U-TEVA Resin or TRU Resin (Eichrom Industries). Small, selective extraction columns do not generate large volumes of liquid waste and provide consistent tracer recoveries after soil matrix elimination.

  13. Magnificent Ground Water Connection. [Sample Activities].

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Washington, DC.

    Water conservation and usage is an important concept in science. This document, geared specifically to New England, provides many activities for protecting and discussing ground water situations. Sample activities for grades K-6 include: (1) All the Water in the World; (2) The Case of the Disappearing Water; (3) Deep Subjects--Wells and Ground…

  14. Constrained sampling method for analytic continuation.

    PubMed

    Sandvik, Anders W

    2016-12-01

    A method for analytic continuation of imaginary-time correlation functions (here obtained in quantum Monte Carlo simulations) to real-frequency spectral functions is proposed. Stochastically sampling a spectrum parametrized by a large number of δ functions, treated as a statistical-mechanics problem, it avoids distortions caused by (as demonstrated here) configurational entropy in previous sampling methods. The key development is the suppression of entropy by constraining the spectral weight to within identifiable optimal bounds and imposing a set number of peaks. As a test case, the dynamic structure factor of the S=1/2 Heisenberg chain is computed. Very good agreement is found with Bethe ansatz results in the ground state (including a sharp edge) and with exact diagonalization of small systems at elevated temperatures.

  15. Constrained sampling method for analytic continuation

    NASA Astrophysics Data System (ADS)

    Sandvik, Anders W.

    2016-12-01

    A method for analytic continuation of imaginary-time correlation functions (here obtained in quantum Monte Carlo simulations) to real-frequency spectral functions is proposed. Stochastically sampling a spectrum parametrized by a large number of δ functions, treated as a statistical-mechanics problem, it avoids distortions caused by (as demonstrated here) configurational entropy in previous sampling methods. The key development is the suppression of entropy by constraining the spectral weight to within identifiable optimal bounds and imposing a set number of peaks. As a test case, the dynamic structure factor of the S =1 /2 Heisenberg chain is computed. Very good agreement is found with Bethe ansatz results in the ground state (including a sharp edge) and with exact diagonalization of small systems at elevated temperatures.

  16. Actinide Recovery Method for Large Soil Samples

    SciTech Connect

    Maxwell, S.L. III; Nichols, S.

    1998-11-01

    A new Actinide Recovery Method has been developed by the Savannah River Site Central Laboratory to preconcentrate actinides in very large soil samples. Diphonix Resin(r) is used eliminate soil matrix interferences and preconcentrate actinides after soil leaching or soil fusion. A rapid microwave digestion technique is used to remove the actinides from the Diphonix Resin(r). After the resin digestion, the actinides are recovered in a small volume of nitric acid which can be easily loaded onto small extraction-chromatography columns, such as TEVA Resin(r), U-TEVA Resin(r) or TRU Resin(r) (Eichrom Industries). This method enables the application of small, selective extraction-columns to recover actinides from very large soil samples with high selectivity, consistent tracer recoveries and minimal liquid waste.

  17. Methods for Sampling of Airborne Viruses

    PubMed Central

    Verreault, Daniel; Moineau, Sylvain; Duchaine, Caroline

    2008-01-01

    Summary: To better understand the underlying mechanisms of aerovirology, accurate sampling of airborne viruses is fundamental. The sampling instruments commonly used in aerobiology have also been used to recover viruses suspended in the air. We reviewed over 100 papers to evaluate the methods currently used for viral aerosol sampling. Differentiating infections caused by direct contact from those caused by airborne dissemination can be a very demanding task given the wide variety of sources of viral aerosols. While epidemiological data can help to determine the source of the contamination, direct data obtained from air samples can provide very useful information for risk assessment purposes. Many types of samplers have been used over the years, including liquid impingers, solid impactors, filters, electrostatic precipitators, and many others. The efficiencies of these samplers depend on a variety of environmental and methodological factors that can affect the integrity of the virus structure. The aerodynamic size distribution of the aerosol also has a direct effect on sampler efficiency. Viral aerosols can be studied under controlled laboratory conditions, using biological or nonbiological tracers and surrogate viruses, which are also discussed in this review. Lastly, general recommendations are made regarding future studies on the sampling of airborne viruses. PMID:18772283

  18. SOIL AND SEDIMENT SAMPLING METHODS | Science ...

    EPA Pesticide Factsheets

    The EPA Office of Solid Waste and Emergency Response's (OSWER) Office of Superfund Remediation and Technology Innovation (OSRTI) needs innovative methods and techniques to solve new and difficult sampling and analytical problems found at the numerous Superfund sites throughout the United States. Inadequate site characterization and a lack of knowledge of surface and subsurface contaminant distributions hinders EPA's ability to make the best decisions on remediation options and to conduct the most effective cleanup efforts. To assist OSWER, NERL conducts research to improve their capability to more accurately, precisely, and efficiently characterize Superfund, RCRA, LUST, oil spills, and brownfield sites and to improve their risk-based decision making capabilities, research is being conducted on improving soil and sediment sampling techniques and improving the sampling and handling of volatile organic compound (VOC) contaminated soils, among the many research programs and tasks being performed at ESD-LV.Under this task, improved sampling approaches and devices will be developed for characterizing the concentration of VOCs in soils. Current approaches and devices used today can lose up to 99% of the VOCs present in the sample due inherent weaknesses in the device and improper/inadequate collection techniques. This error generally causes decision makers to markedly underestimate the soil VOC concentrations and, therefore, to greatly underestimate the ecological

  19. Flow cytometric detection method for DNA samples

    DOEpatents

    Nasarabadi,Shanavaz; Langlois, Richard G.; Venkateswaran, Kodumudi S.

    2011-07-05

    Disclosed herein are two methods for rapid multiplex analysis to determine the presence and identity of target DNA sequences within a DNA sample. Both methods use reporting DNA sequences, e.g., modified conventional Taqman.RTM. probes, to combine multiplex PCR amplification with microsphere-based hybridization using flow cytometry means of detection. Real-time PCR detection can also be incorporated. The first method uses a cyanine dye, such as, Cy3.TM., as the reporter linked to the 5' end of a reporting DNA sequence. The second method positions a reporter dye, e.g., FAM.TM. on the 3' end of the reporting DNA sequence and a quencher dye, e.g., TAMRA.TM., on the 5' end.

  20. Flow cytometric detection method for DNA samples

    DOEpatents

    Nasarabadi, Shanavaz; Langlois, Richard G.; Venkateswaran, Kodumudi S.

    2006-08-01

    Disclosed herein are two methods for rapid multiplex analysis to determine the presence and identity of target DNA sequences within a DNA sample. Both methods use reporting DNA sequences, e.g., modified conventional Taqman.RTM. probes, to combine multiplex PCR amplification with microsphere-based hybridization using flow cytometry means of detection. Real-time PCR detection can also be incorporated. The first method uses a cyanine dye, such as, Cy3.TM., as the reporter linked to the 5' end of a reporting DNA sequence. The second method positions a reporter dye, e.g., FAM, on the 3' end of the reporting DNA sequence and a quencher dye, e.g., TAMRA, on the 5' end.

  1. Field evaluation of a VOST sampling method

    SciTech Connect

    Jackson, M.D.; Johnson, L.D.; Fuerst, R.G.; McGaughey, J.F.; Bursey, J.T.; Merrill, R.G.

    1994-12-31

    The VOST (SW-846 Method 0030) specifies the use of Tenax{reg_sign} and a particular petroleum-based charcoal (SKC Lot 104, or its equivalent), that is no longer commercially available. In field evaluation studies of VOST methodology, a replacement petroleum-based charcoal has been used: candidate replacement sorbents for charcoal were studied, and Anasorb{reg_sign} 747, a carbon-based sorbent, was selected for field testing. The sampling train was modified to use only Anasorb{reg_sign} in the back tube and Tenax{reg_sign} in the two front tubes to avoid analytical difficulties associated with the analysis of the sequential bed back tube used in the standard VOST train. The standard (SW-846 Method 0030) and the modified VOST methods were evaluated at a chemical manufacturing facility using a quadruple probe system with quadruple trains. In this field test, known concentrations of the halogenated volatile organic compounds, that are listed in the Clean Air Act Amendments of 1990, Title 3, were introduced into the VOST train and the modified VOST train, using the same certified gas cylinder as a source of test compounds. Statistical tests of the comparability of methods were performed on a compound-by-compound basis. For most compounds, the VOST and modified VOST methods were found to be statistically equivalent.

  2. Method and apparatus for sampling low-yield wells

    DOEpatents

    Last, George V.; Lanigan, David C.

    2003-04-15

    An apparatus and method for collecting a sample from a low-yield well or perched aquifer includes a pump and a controller responsive to water level sensors for filling a sample reservoir. The controller activates the pump to fill the reservoir when the water level in the well reaches a high level as indicated by the sensor. The controller deactivates the pump when the water level reaches a lower level as indicated by the sensors. The pump continuously activates and deactivates the pump until the sample reservoir is filled with a desired volume, as indicated by a reservoir sensor. At the beginning of each activation cycle, the controller optionally can select to purge an initial quantity of water prior to filling the sample reservoir. The reservoir can be substantially devoid of air and the pump is a low volumetric flow rate pump. Both the pump and the reservoir can be located either inside or outside the well.

  3. DOE methods for evaluating environmental and waste management samples

    SciTech Connect

    Goheen, S.C.; McCulloch, M.; Thomas, B.L.; Riley, R.G.; Sklarew, D.S.; Mong, G.M.; Fadeff, S.K.

    1994-10-01

    DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) is a resource intended to support sampling and analytical activities for the evaluation of environmental and waste management samples from U.S. Department of Energy (DOE) sites. DOE Methods is the result of extensive cooperation from all DOE analytical laboratories. All of these laboratories have contributed key information and provided technical reviews as well as significant moral support leading to the success of this document. DOE Methods is designed to encompass methods for collecting representative samples and for determining the radioisotope activity and organic and inorganic composition of a sample. These determinations will aid in defining the type and breadth of contamination and thus determine the extent of environmental restoration or waste management actions needed, as defined by the DOE, the U.S. Environmental Protection Agency, or others. The development of DOE Methods is supported by the Analytical Services Division of DOE. Unique methods or methods consolidated from similar procedures in the DOE Procedures Database are selected for potential inclusion in this document. Initial selection is based largely on DOE needs and procedure applicability and completeness. Methods appearing in this document are one of two types, {open_quotes}Draft{close_quotes} or {open_quotes}Verified{close_quotes}. {open_quotes}Draft{close_quotes} methods that have been reviewed internally and show potential for eventual verification are included in this document, but they have not been reviewed externally, and their precision and bias may not be known. {open_quotes}Verified{close_quotes} methods in DOE Methods have been reviewed by volunteers from various DOE sites and private corporations. These methods have delineated measures of precision and accuracy.

  4. Use of a novel radiometric method to assess the inhibitory effect of donepezil on acetylcholinesterase activity in minimally diluted tissue samples

    PubMed Central

    Kikuchi, Tatsuya; Okamura, Toshimitsu; Arai, Takuya; Obata, Takayuki; Fukushi, Kiyoshi; Irie, Toshiaki; Shiraishi, Tetsuya

    2010-01-01

    Background and purpose: Cholinesterase inhibitors have been widely used for the treatment of patients with dementia. Monitoring of the cholinesterase activity in the blood is used as an indicator of the effect of the cholinesterase inhibitors in the brain. The selective measurement of cholinesterase with low tissue dilution is preferred for accurate monitoring; however, the methods have not been established. Here, we investigated the effect of tissue dilution on the action of cholinesterase inhibitors using a novel radiometric method with selective substrates, N-[14C]methylpiperidin-4-yl acetate ([14C]MP4A) and (R)-N-[14C]methylpiperidin-3-yl butyrate ([14C]MP3B_R), for AChE and butyrylcholinesterase (BChE) respectively. Experimental approach: We investigated the kinetics of hydrolysis of [14C]-MP4A and [14C]-MP3B_R by cholinesterases, and evaluated the selectivity of [14C]MP4A and [14C]MP3B_R for human AChE and BChE, respectively, compared with traditional substrates. Then, IC50 values of cholinesterase inhibitors in minimally diluted and highly diluted tissues were measured with [14C]MP4A and [14C]MP3B_R. Key results: AChE and BChE activities were selectively measured as the first-order hydrolysis rates of [14C]-MP4A and [14C]MP3B_R respectively. The AChE selectivity of [14C]MP4A was an order of magnitude higher than traditional substrates used for the AChE assay. The IC50 values of specific AChE and BChE inhibitors, donepezil and ethopropazine, in 1.2-fold diluted human whole blood were much higher than those in 120-fold diluted blood. In addition, the IC50 values of donepezil in monkey brain were dramatically decreased as the tissue was diluted. Conclusions and implications: This method would effectively monitor the activity of cholinesterase inhibitors used for therapeutics, pesticides and chemical warfare agents. PMID:20401964

  5. System and Method for Isolation of Samples

    NASA Technical Reports Server (NTRS)

    Zhang, Ye (Inventor); Wu, Honglu (Inventor)

    2014-01-01

    Systems and methods for isolating samples are provided. The system comprises a first membrane and a second membrane disposed within an enclosure. First and second reservoirs can also be disposed within the enclosure and adapted to contain one or more reagents therein. A first valve can be disposed within the enclosure and in fluid communication with the first reservoir, the second reservoir, or both. The first valve can also be in fluid communication with the first or second membranes or both. The first valve can be adapted to selectively regulate the flow of the reagents from the first reservoir, through at least one of the first and second membranes, and into the second reservoir.

  6. Bacillus polymachus sp. nov., with a broad range of antibacterial activity, isolated from forest topsoil samples by using a modified culture method.

    PubMed

    Nguyen, Tuan Manh; Kim, Jaisoo

    2015-02-01

    A new, modified culture method that utilizes a transwell plate with a 0.4 µm pore-size microporous membrane was developed. This system allows only trace nutrients from the soil into the liquid culture through the microporous membrane. The method is a more powerful tool for the discovery of novel species from soils than are traditional methods. Such newly identified species could potentially produce useful metabolites. A bacterial strain, T515(T), was isolated using this modified culture method. Growth of strain T515(T) occurred at pH 4-9 in a temperature range between 20 °C and 40 °C and in the presence of 0-2 % (w/v) NaCl on R2A agar. Colonies on the agar plates were tiny, white, and convex after 5 days incubation at 28 °C. Comparative analysis of the nearly full-length 16S rRNA gene sequence of strain T515(T) revealed close pairwise similarity with species of the genus Bacillus, and strain T515(T) was most closely related to Bacillus panaciterrae Gsoil 1517(T) (96.7 %) and Bacillus funiculus NAF001(T) (96.0 %). The major quinone of strain T515(T) was menaquinone-7 (MK-7) and the major fatty acids were iso-C15 : 0 (45.5 %), anteiso-C15 : 0 (23.2 %) and C16 : 0 (10.9 %). The predominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Strain T515(T) was sensitive to streptomycin and tetracycline, but resistant to rifampicin (0.125 µg ml(-1)), ampicillin (0.5 µg ml(-1)) and chloramphenicol (1 µg ml(-1)). The strain showed antimicrobial activities against the six strains tested: Bacillus subtilis KEMB 51201-001, Staphylococcus aureus KEMB 4659, Pseudomonas aeruginosa KACC 10185, Staphylococcus epidermidis KACC 13234, Paenibacillus larvae KACC 14031 and Escherichia coli KEMB 212-234. Based on these results, strain T515(T) represents a novel species of the genus Bacillus with the proposed name, Bacillus polymachus sp. nov. The type strain is T515(T) ( = KEMB 9005-168(T) = KACC 18242(T) = NBRC 110614(T)).

  7. Battery equalization active methods

    NASA Astrophysics Data System (ADS)

    Gallardo-Lozano, Javier; Romero-Cadaval, Enrique; Milanes-Montero, M. Isabel; Guerrero-Martinez, Miguel A.

    2014-01-01

    Many different battery technologies are available for the applications which need energy storage. New researches are being focused on Lithium-based batteries, since they are becoming the most viable option for portable energy storage applications. As most of the applications need series battery strings to meet voltage requirements, battery imbalance is an important matter to be taken into account, since it leads the individual battery voltages to drift apart over time, and premature cells degradation, safety hazards, and capacity reduction will occur. A large number of battery equalization methods can be found, which present different advantages/disadvantages and are suitable for different applications. The present paper presents a summary, comparison and evaluation of the different active battery equalization methods, providing a table that compares them, which is helpful to select the suitable equalization method depending on the application. By applying the same weight to the different parameters of comparison, switch capacitor and double-tiered switching capacitor have the highest ratio. Cell bypass methods are cheap and cell to cell ones are efficient. Cell to pack, pack to cell and cell to pack to cell methods present a higher cost, size, and control complexity, but relatively low voltage and current stress in high-power applications.

  8. Evaluation of Sampling Methods for Bacillus Spore ...

    EPA Pesticide Factsheets

    Journal Article Following a wide area release of biological materials, mapping the extent of contamination is essential for orderly response and decontamination operations. HVAC filters process large volumes of air and therefore collect highly representative particulate samples in buildings. HVAC filter extraction may have great utility in rapidly estimating the extent of building contamination following a large-scale incident. However, until now, no studies have been conducted comparing the two most appropriate sampling approaches for HVAC filter materials: direct extraction and vacuum-based sampling.

  9. Well fluid isolation and sample apparatus and method

    DOEpatents

    Schalla, Ronald; Smith, Ronald M.; Hall, Stephen H.; Smart, John E.

    1995-01-01

    The present invention specifically permits purging and/or sampling of a well but only removing, at most, about 25% of the fluid volume compared to conventional methods and, at a minimum, removing none of the fluid volume from the well. The invention is an isolation assembly that is inserted into the well. The isolation assembly is designed so that only a volume of fluid between the outside diameter of the isolation assembly and the inside diameter of the well over a fluid column height from the bottom of the well to the top of the active portion (lower annulus) is removed. A seal may be positioned above the active portion thereby sealing the well and preventing any mixing or contamination of inlet fluid with fluid above the packer. Purged well fluid is stored in a riser above the packer. Ports in the wall of the isolation assembly permit purging and sampling of the lower annulus along the height of the active portion.

  10. The experience sampling method: Investigating students' affective experience

    NASA Astrophysics Data System (ADS)

    Nissen, Jayson M.; Stetzer, MacKenzie R.; Shemwell, Jonathan T.

    2013-01-01

    Improving non-cognitive outcomes such as attitudes, efficacy, and persistence in physics courses is an important goal of physics education. This investigation implemented an in-the-moment surveying technique called the Experience Sampling Method (ESM) [1] to measure students' affective experience in physics. Measurements included: self-efficacy, cognitive efficiency, activation, intrinsic motivation, and affect. Data are presented that show contrasts in students' experiences (e.g., in physics vs. non-physics courses).

  11. System and method for extracting a sample from a surface

    DOEpatents

    Van Berkel, Gary; Covey, Thomas

    2015-06-23

    A system and method is disclosed for extracting a sample from a sample surface. A sample is provided and a sample surface receives the sample which is deposited on the sample surface. A hydrophobic material is applied to the sample surface, and one or more devices are configured to dispense a liquid on the sample, the liquid dissolving the sample to form a dissolved sample material, and the one or more devices are configured to extract the dissolved sample material from the sample surface.

  12. Simultaneous quantitation of 14 active components in Yinchenhao decoction by using ultra high performance liquid chromatography with diode array detection: Method development and ingredient analysis of different commonly prepared samples.

    PubMed

    Yi, YaXiong; Zhang, Yong; Ding, Yue; Lu, Lu; Zhang, Tong; Zhao, Yuan; Xu, XiaoJun; Zhang, YuXin

    2016-11-01

    We developed a novel quantitative analysis method based on ultra high performance liquid chromatography coupled with diode array detection for the simultaneous determination of the 14 main active components in Yinchenhao decoction. All components were separated on an Agilent SB-C18 column by using a gradient solvent system of acetonitrile/0.1% phosphoric acid solution at a flow rate of 0.4 mL/min for 35 min. Subsequently, linearity, precision, repeatability, and accuracy tests were implemented to validate the method. Furthermore, the method has been applied for compositional difference analysis of 14 components in eight normal-extraction Yinchenhao decoction samples, accompanied by hierarchical clustering analysis and similarity analysis. The result that all samples were divided into three groups based on different contents of components demonstrated that extraction methods of decocting, refluxing, ultrasonication and extraction solvents of water or ethanol affected component differentiation, and should be related to its clinical applications. The results also indicated that the sample prepared by patients in the family by using water extraction employing a casserole was almost same to that prepared using a stainless-steel kettle, which is mostly used in pharmaceutical factories. This research would help patients to select the best and most convenient method for preparing Yinchenhao decoction.

  13. Exploration and Sampling Methods for Borrow Areas

    DTIC Science & Technology

    1990-12-01

    The principal geomorphic features associated with stratified deposits are kames, eskers , and proglacial outwash material. 60. Kames are moundlike...deposits without obtaining core samples or geophysical data. 61. Eskers are sinuous ridgelike features that form in channels, tun- nels, and crevasses in...the ice by meltwater transport and deposition of gla- cial material. Eskers are variable in dimensions but, at their largest, can be up to 100 m high

  14. A method for sampling waste corn

    USGS Publications Warehouse

    Frederick, R.B.; Klaas, E.E.; Baldassarre, G.A.; Reinecke, K.J.

    1984-01-01

    Corn had become one of the most important wildlife food in the United States. It is eaten by a wide variety of animals, including white-tailed deer (Odocoileus virginianus ), raccoon (Procyon lotor ), ring-necked pheasant (Phasianus colchicus , wild turkey (Meleagris gallopavo ), and many species of aquatic birds. Damage to unharvested crops had been documented, but many birds and mammals eat waste grain after harvest and do not conflict with agriculture. A good method for measuring waste-corn availability can be essential to studies concerning food density and food and feeding habits of field-feeding wildlife. Previous methods were developed primarily for approximating losses due to harvest machinery. In this paper, a method is described for estimating the amount of waste corn potentially available to wildlife. Detection of temporal changes in food availability and differences caused by agricultural operations (e.g., recently harvested stubble fields vs. plowed fields) are discussed.

  15. [DOE method for evaluating environmental and waste management samples: Revision 1, Addendum 1

    SciTech Connect

    Goheen, S.C.

    1995-04-01

    The US Dapartment of Energy`s (DOE`s) environmental and waste management (EM) sampling and analysis activities require that large numbers of samples be analyzed for materials characterization, environmental surveillance, and site-remediation programs. The present document, DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods), is a supplemental resource for analyzing many of these samples.

  16. Sampling Host-Seeking Anthropophilic Mosquito Vectors in West Africa: Comparisons of An Active Human-Baited Tent-Trap against Gold Standard Methods

    PubMed Central

    Krajacich, Benjamin J.; Slade, Jeremiah R.; Mulligan, Robert F.; LaBrecque, Brendan; Alout, Haoues; Grubaugh, Nathan D.; Meyers, Jacob I.; Fakoli, Lawrence S.; Bolay, Fatorma K.; Brackney, Doug E.; Burton, Timothy A.; Seaman, Jonathan A.; Diclaro, Joseph W.; Dabiré, Roch K.; Foy, Brian D.

    2015-01-01

    In this study, we characterize the ability of the previously described Infoscitex tent (IST) to capture mosquitoes in comparison to either the Centers for Disease Control Light Trap hung next to individuals under a bed net (LTC) or to human landing catches (HLC). In Senegal, the IST caught 6.14 times the number of Anopheles gambiae sensu lato (s.l.), and 8.78 times the Culex group V mosquitoes as LTC. In one of two locations in Burkina Faso, the IST caught An. gambiae at a rate not significantly different than HLC. Of importance, 9.1–36.1% of HLC caught An. gambiae were blood fed, mostly with fresh blood, suggesting they fed upon the collector, whereas only 0.5–5.0% from the IST had partial or old blood. The IST also caught outdoor biting species in proportions comparable to HLC. The results show this tent provides a safer and effective alternative to the skill-dependent, risky, and laborious HLC method. PMID:25422393

  17. Sampling host-seeking anthropophilic mosquito vectors in west Africa: comparisons of an active human-baited tent-trap against gold standard methods.

    PubMed

    Krajacich, Benjamin J; Slade, Jeremiah R; Mulligan, Robert F; LaBrecque, Brendan; Alout, Haoues; Grubaugh, Nathan D; Meyers, Jacob I; Fakoli, Lawrence S; Bolay, Fatorma K; Brackney, Doug E; Burton, Timothy A; Seaman, Jonathan A; Diclaro, Joseph W; Dabiré, Roch K; Foy, Brian D

    2015-02-01

    In this study, we characterize the ability of the previously described Infoscitex tent (IST) to capture mosquitoes in comparison to either the Centers for Disease Control Light Trap hung next to individuals under a bed net (LTC) or to human landing catches (HLC). In Senegal, the IST caught 6.14 times the number of Anopheles gambiae sensu lato (s.l.), and 8.78 times the Culex group V mosquitoes as LTC. In one of two locations in Burkina Faso, the IST caught An. gambiae at a rate not significantly different than HLC. Of importance, 9.1-36.1% of HLC caught An. gambiae were blood fed, mostly with fresh blood, suggesting they fed upon the collector, whereas only 0.5-5.0% from the IST had partial or old blood. The IST also caught outdoor biting species in proportions comparable to HLC. The results show this tent provides a safer and effective alternative to the skill-dependent, risky, and laborious HLC method.

  18. Modified electrokinetic sample injection method in chromatography and electrophoresis analysis

    DOEpatents

    Davidson, J. Courtney; Balch, Joseph W.

    2001-01-01

    A sample injection method for horizontal configured multiple chromatography or electrophoresis units, each containing a number of separation/analysis channels, that enables efficient introduction of analyte samples. This method for loading when taken in conjunction with horizontal microchannels allows much reduced sample volumes and a means of sample stacking to greatly reduce the concentration of the sample. This reduction in the amount of sample can lead to great cost savings in sample preparation, particularly in massively parallel applications such as DNA sequencing. The essence of this method is in preparation of the input of the separation channel, the physical sample introduction, and subsequent removal of excess material. By this method, sample volumes of 100 nanoliter to 2 microliters have been used successfully, compared to the typical 5 microliters of sample required by the prior separation/analysis method.

  19. Surface Sampling Methods for Bacillus anthracis Spore Contamination

    PubMed Central

    Hein, Misty J.; Taylor, Lauralynn; Curwin, Brian D.; Kinnes, Gregory M.; Seitz, Teresa A.; Popovic, Tanja; Holmes, Harvey T.; Kellum, Molly E.; McAllister, Sigrid K.; Whaley, David N.; Tupin, Edward A.; Walker, Timothy; Freed, Jennifer A.; Small, Dorothy S.; Klusaritz, Brian; Bridges, John H.

    2002-01-01

    During an investigation conducted December 17–20, 2001, we collected environmental samples from a U.S. postal facility in Washington, D.C., known to be extensively contaminated with Bacillus anthracis spores. Because methods for collecting and analyzing B. anthracis spores have not yet been validated, our objective was to compare the relative effectiveness of sampling methods used for collecting spores from contaminated surfaces. Comparison of wipe, wet and dry swab, and HEPA vacuum sock samples on nonporous surfaces indicated good agreement between results with HEPA vacuum and wipe samples. However, results from HEPA vacuum sock and wipe samples agreed poorly with the swab samples. Dry swabs failed to detect spores >75% of the time they were detected by wipe and HEPA vacuum samples. Wipe samples collected after HEPA vacuum samples and HEPA vacuum samples after wipe samples indicated that neither method completely removed spores from the sampled surfaces. PMID:12396930

  20. 7 CFR 58.245 - Method of sample analysis.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Method of sample analysis. 58.245 Section 58.245... Procedures § 58.245 Method of sample analysis. Samples shall be tested according to the applicable methods of laboratory analysis contained in either DA Instruction 918-RL as issued by the USDA, Agricultural...

  1. 7 CFR 58.812 - Methods of sample analysis.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Methods of sample analysis. 58.812 Section 58.812... Procedures § 58.812 Methods of sample analysis. Samples shall be tested according to the applicable methods of laboratory analysis contained in either DA Instruction 918-RL, as issued by the USDA,...

  2. 7 CFR 58.812 - Methods of sample analysis.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Methods of sample analysis. 58.812 Section 58.812... Procedures § 58.812 Methods of sample analysis. Samples shall be tested according to the applicable methods of laboratory analysis contained in either DA Instruction 918-RL, as issued by the USDA,...

  3. 7 CFR 58.245 - Method of sample analysis.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Method of sample analysis. 58.245 Section 58.245... Procedures § 58.245 Method of sample analysis. Samples shall be tested according to the applicable methods of laboratory analysis contained in either DA Instruction 918-RL as issued by the USDA, Agricultural...

  4. Microfluidic DNA sample preparation method and device

    DOEpatents

    Krulevitch, Peter A.; Miles, Robin R.; Wang, Xiao-Bo; Mariella, Raymond P.; Gascoyne, Peter R. C.; Balch, Joseph W.

    2002-01-01

    Manipulation of DNA molecules in solution has become an essential aspect of genetic analyses used for biomedical assays, the identification of hazardous bacterial agents, and in decoding the human genome. Currently, most of the steps involved in preparing a DNA sample for analysis are performed manually and are time, labor, and equipment intensive. These steps include extraction of the DNA from spores or cells, separation of the DNA from other particles and molecules in the solution (e.g. dust, smoke, cell/spore debris, and proteins), and separation of the DNA itself into strands of specific lengths. Dielectrophoresis (DEP), a phenomenon whereby polarizable particles move in response to a gradient in electric field, can be used to manipulate and separate DNA in an automated fashion, considerably reducing the time and expense involved in DNA analyses, as well as allowing for the miniaturization of DNA analysis instruments. These applications include direct transport of DNA, trapping of DNA to allow for its separation from other particles or molecules in the solution, and the separation of DNA into strands of varying lengths.

  5. Sample storage for soil enzyme activity and bacterial community profiles.

    PubMed

    Wallenius, K; Rita, H; Simpanen, S; Mikkonen, A; Niemi, R M

    2010-04-01

    Storage of samples is often an unavoidable step in environmental data collection, since available analytical capacity seldom permits immediate processing of large sample sets needed for representative data. In microbiological soil studies, sample pretreatments may have a strong influence on measurement results, and thus careful consideration is required in the selection of storage conditions. The aim of this study was to investigate the suitability of prolonged (up to 16 weeks) frozen or air-dried storage for divergent soil materials. The samples selected to this study were mineral soil (clay loam) from an agricultural field, humus from a pine forest and compost from a municipal sewage sludge composting field. The measured microbiological parameters included functional profiling with ten different hydrolysing enzyme activities determined by artificial fluorogenic substrates, and structural profiling with bacterial 16S rDNA community fingerprints by amplicon length heterogeneity analysis (LH-PCR). Storage of samples affected the observed fluorescence intensity of the enzyme assay's fluorophor standards dissolved in soil suspension. The impact was highly dependent on the soil matrix and storage method, making it important to use separate standardisation for each combination of matrix type, storage method and time. Freezing proved to be a better storage method than air-drying for all the matrices and enzyme activities studied. The effect of freezing on the enzyme activities was small (<20%) in clay loam and forest humus and moderate (generally 20-30%) in compost. The most dramatic decreases (>50%) in activity were observed in compost after air-drying. The bacterial LH-PCR community fingerprints were unaffected by frozen storage in all matrices. The effect of storage treatments was tested using a new statistical method based on showing similarity rather than difference of results.

  6. Method for sampling sub-micron particles

    DOEpatents

    Gay, Don D.; McMillan, William G.

    1985-01-01

    Apparatus and method steps for collecting sub-micron sized particles include a collection chamber and cryogenic cooling. The cooling is accomplished by coil tubing carrying nitrogen in liquid form, with the liquid nitrogen changing to the gas phase before exiting from the collection chamber in the tubing. Standard filters are used to filter out particles of diameter greater than or equal to 0.3 microns; however the present invention is used to trap particles of less than 0.3 micron in diameter. A blower draws air to said collection chamber through a filter which filters particles with diameters greater than or equal to 0.3 micron. The air is then cryogenically cooled so that moisture and sub-micron sized particles in the air condense into ice on the coil. The coil is then heated so that the ice melts, and the liquid is then drawn off and passed through a Buchner funnel where the liquid is passed through a Nuclepore membrane. A vacuum draws the liquid through the Nuclepore membrane, with the Nuclepore membrane trapping sub-micron sized particles therein. The Nuclepore membrane is then covered on its top and bottom surfaces with sheets of Mylar.RTM. and the assembly is then crushed into a pellet. This effectively traps the sub-micron sized particles for later analysis.

  7. Methods for characterizing, classifying, and identifying unknowns in samples

    DOEpatents

    Grate, Jay W [West Richland, WA; Wise, Barry M [Manson, WA

    2002-01-01

    Disclosed is a method for taking the data generated from an array of responses from a multichannel instrument, and determining the characteristics of a chemical in the sample without the necessity of calibrating or training the instrument with known samples containing the same chemical. The characteristics determined by the method are then used to classify and identify the chemical in the sample. The method can also be used to quantify the concentration of the chemical in the sample.

  8. Methods for characterizing, classifying, and identifying unknowns in samples

    DOEpatents

    Grate, Jay W.; Wise, Barry M.

    2003-08-12

    Disclosed is a method for taking the data generated from an array of responses from a multichannel instrument, and determining the characteristics of a chemical in the sample without the necessity of calibrating or training the instrument with known samples containing the same chemical. The characteristics determined by the method are then used to classify and identify the chemical in the sample. The method can also be used to quantify the concentration of the chemical in the sample.

  9. Quantification of 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5), a newly synthetized P-glycoprotein inducer/activator, in biological samples: method development and validation.

    PubMed

    Ferreira, Ana Filipa; Ponte, Filipa; Silva, Renata; Rocha-Pereira, Carolina; Sousa, Emília; Pinto, Madalena; Bastos, Maria de Lourdes; Remião, Fernando

    2017-02-01

    A simple, rapid and economical method was developed and validated for the analysis and quantification of 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5), a P-glycoprotein inducer/activator, in biological samples, using reverse-phase high-performance liquid chromatography (HPLC). A C18 column and a mobile phase composed of methanol-water (90/10, v/v) with 1% (v/v) triethylamine, at a flow rate of 1 mL/min, were used for chromatographic separation. TX5 standards (0.5-150 μm) were prepared in human serum. Methanol was used for TX5 extraction and serum protein precipitation. After filtration, samples were injected into the HPLC apparatus and TX5 was quantified by a conventional UV detector at 255 nm. The TX5 retention time was 13 min in this isocratic system. The method was validated according to ICH guidelines for specificity/selectivity, linearity, accuracy, precision, limits of detection and quantification (LOD and LOQ) and recovery. The method was proved to be selective, as there were no interferences of endogenous compounds with the same retention time of TX5. Also, the developed method was linear (r(2)  ≥ 0.99) for TX5 concentrations between 0.5 and 150 μm and the LOD and LOQ were 0.08 and 0.23 μm, respectively. The results indicated that the reported method could meet the requirements for TX5 analysis in the trace amounts expected to be present in biological samples.

  10. Sampling Methods in Cardiovascular Nursing Research: An Overview.

    PubMed

    Kandola, Damanpreet; Banner, Davina; O'Keefe-McCarthy, Sheila; Jassal, Debbie

    2014-01-01

    Cardiovascular nursing research covers a wide array of topics from health services to psychosocial patient experiences. The selection of specific participant samples is an important part of the research design and process. The sampling strategy employed is of utmost importance to ensure that a representative sample of participants is chosen. There are two main categories of sampling methods: probability and non-probability. Probability sampling is the random selection of elements from the population, where each element of the population has an equal and independent chance of being included in the sample. There are five main types of probability sampling including simple random sampling, systematic sampling, stratified sampling, cluster sampling, and multi-stage sampling. Non-probability sampling methods are those in which elements are chosen through non-random methods for inclusion into the research study and include convenience sampling, purposive sampling, and snowball sampling. Each approach offers distinct advantages and disadvantages and must be considered critically. In this research column, we provide an introduction to these key sampling techniques and draw on examples from the cardiovascular research. Understanding the differences in sampling techniques may aid nurses in effective appraisal of research literature and provide a reference pointfor nurses who engage in cardiovascular research.

  11. Simultaneous quantitation of 14 active components in Yinchenhao decoction with an ultrahigh performance liquid chromatography-diode array detector: Method development and ingredient analysis of different commonly prepared samples.

    PubMed

    Yi, YaXiong; Zhang, Yong; Ding, Yue; Lu, Lu; Zhang, Tong; Zhao, Yuan; Xu, XiaoJun; Zhang, YuXin

    2016-11-01

    J. Sep. Sci. 2016, 39, 4147-4157 DOI: 10.1002/jssc.201600284 Yinchenhao decoction (YCHD) is a famous Chinese herbal formula recorded in the Shang Han Lun which was prescribed by Zhongjing Zhang during 150-219 AD. A novel quantitative analysis method was developed, based on ultrahigh performance liquid chromatography coupled with a diode array detector for the simultaneous determination of 14 main active components in Yinchenhao decoction. Furthermore, the method has been applied for compositional difference analysis of the 14 components in eight normal extraction samples of Yinchenhao decoction, with the aid of hierarchical clustering analysis and similarity analysis. The present research could help hospital, factory and lab choose the best way to make Yinchenhao decoction with better efficacy.

  12. Active Learning Methods

    ERIC Educational Resources Information Center

    Zayapragassarazan, Z.; Kumar, Santosh

    2012-01-01

    Present generation students are primarily active learners with varied learning experiences and lecture courses may not suit all their learning needs. Effective learning involves providing students with a sense of progress and control over their own learning. This requires creating a situation where learners have a chance to try out or test their…

  13. Photoacoustic sample vessel and method of elevated pressure operation

    DOEpatents

    Autrey, Tom; Yonker, Clement R.

    2004-05-04

    An improved photoacoustic vessel and method of photoacoustic analysis. The photoacoustic sample vessel comprises an acoustic detector, an acoustic couplant, and an acoustic coupler having a chamber for holding the acoustic couplant and a sample. The acoustic couplant is selected from the group consisting of liquid, solid, and combinations thereof. Passing electromagnetic energy through the sample generates an acoustic signal within the sample, whereby the acoustic signal propagates through the sample to and through the acoustic couplant to the acoustic detector.

  14. Personal sampling of airborne particles: method performance and data quality.

    PubMed

    Janssen, N A; Hoek, G; Harssema, H; Brunekreef, B

    1998-01-01

    A study of personal exposure to respirable particles (PM10) and fine particles (FP) was conducted in groups of 50-70 year-old adults and primary school children in the Netherlands. Four to eight personal measurements per subject were conducted, on weekdays only. Averaging time was 24 hours. Method performance was evaluated regarding compliance, flow, weighing procedure, field blanks and co-located operation of the personal samplers with stationary methods. Furthermore, the possibility that subjects change their behavior due to the wearing of personal sampling equipment was studied by comparing time activity on days of personal sampling with time activity other weekdays. Compliance was high; 95% of the subjects who agreed to continue participating after the first measurement, successfully completed the study, and, expect for the first two days of FP sampling, over 90% of all personal measurements were successful. All pre and post sampling flow readings were within 10% of the required flow rate of 4 L/min. For PM10 precision of the gravimetric analyses was 2.8 microgram/m3 and 0.7 micrograms/m3 for filters weighted on an analytical and a micro-balance respectively. The detection limit was 10.8 micrograms/m3 and 8.6 micrograms/m3 respectively. For FP, weighing precision was 0.4 micrograms/m3 and the detection limit was 5.3 micrograms/m3. All measurements were above the detection limit. Co-located operation of the personal sampler with stationary samplers gave highly correlated concentration (R > 0.90). Outdoor PM10 concentrations measured with the personal sampler were on average 4% higher compared to a Sierra Anderson (SA) inlet and 9% higher compared to a PM10 Harvard Impactor (HI). With the FP cyclone 6% higher classroom concentrations were measured compared to a PM2.5 HI. Adults spent significantly less time outdoor (0.5 hour) and more time at home (0.9 hour) on days of personal sampling compared to other weekdays. For children no significant differences in time

  15. UFLC-MS/MS method for simultaneous determination of six lignans of Schisandra chinensis (Turcz.) Baill. in normal and insomniac rats brain microdialysates and homogenate samples: towards an in-depth study for its sedative-hypnotic activity.

    PubMed

    Wei, Binbin; Li, Qing; Fan, Ronghua; Su, Dan; Ou, Xiuli; Chen, Kelin; Chen, Xiaohui; Jia, Ying; Bi, Kaishun

    2013-04-01

    Schisandra chinensis (Turcz.) Baill., a traditional Chinese medicine, has been clinically used for the treatment of insomnia for centuries. The insomnia mechanism and the possible active ingredients of S. chinensis remain largely unknown. The objective of this study was to develop a method to detect its components which could pass through the blood brain barrier (BBB) by determining the brain microdialysate and brain tissue homogenate samples and then obtain the pharmacokinetic profile in brain for comprehensive understanding of its hypnotic clinical efficacy. Therefore, an efficient, sensitive and selective ultra fast liquid chromatography/tandem mass spectrometry method for the simultaneous determination of six sedative and hypnotic lignans (schisandrin, schisandrol B, schisantherin A, deoxyshisandrin, γ-schisandrin and gomisin N) of Schisandra chinensis (Turcz.) Baill. in rat brain tissue homogenate and brain microdialysates has been developed and validated. The analysis was performed on a Shim-pack XR-ODS column (75 mm × 3.0 mm, 2.2 µm) using gradient elution with the mobile phase consisting of acetonitrile and 0.1% formic acid water. The method was validated in brain homogenate and microdialysate samples, which all showed good linearity over a wide concentration range (r(2)> 0.99), and the obtained lower limit of quantification was 0.1 ng · ml(-1) for the analytes in brain microdialysate samples. The intra- and inter-day assay variability was less than 15% for all analytes. The study proved the six lignans, as sedative and hypnotic ingredients, could pass through the BBB with brain targeting, distributed mainly in the hypothalamus and possessed complete pharmacokinetics process in brain. The results also indicated that significant difference in pharmacokinetic parameters of the analytes was observed between two groups, while absorptions of these analytes in insomniac group were significantly better than those in normal group.

  16. Systems and methods for self-synchronized digital sampling

    NASA Technical Reports Server (NTRS)

    Samson, Jr., John R. (Inventor)

    2008-01-01

    Systems and methods for self-synchronized data sampling are provided. In one embodiment, a system for capturing synchronous data samples is provided. The system includes an analog to digital converter adapted to capture signals from one or more sensors and convert the signals into a stream of digital data samples at a sampling frequency determined by a sampling control signal; and a synchronizer coupled to the analog to digital converter and adapted to receive a rotational frequency signal from a rotating machine, wherein the synchronizer is further adapted to generate the sampling control signal, and wherein the sampling control signal is based on the rotational frequency signal.

  17. Sampling bee communities using pan traps: alternative methods increase sample size

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Monitoring of the status of bee populations and inventories of bee faunas require systematic sampling. Efficiency and ease of implementation has encouraged the use of pan traps to sample bees. Efforts to find an optimal standardized sampling method for pan traps have focused on pan trap color. Th...

  18. Measurements of 55Fe activity in activated steel samples with GEMPix

    NASA Astrophysics Data System (ADS)

    Curioni, A.; Dinar, N.; La Torre, F. P.; Leidner, J.; Murtas, F.; Puddu, S.; Silari, M.

    2017-03-01

    In this paper we present a novel method, based on the recently developed GEMPix detector, to measure the 55Fe content in samples of metallic material activated during operation of CERN accelerators and experimental facilities. The GEMPix, a gas detector with highly pixelated read-out, has been obtained by coupling a triple Gas Electron Multiplier (GEM) to a quad Timepix ASIC. Sample preparation, measurements performed on 45 samples and data analysis are described. The calibration factor (counts per second per unit specific activity) has been obtained via measurements of the 55Fe activity determined by radiochemical analysis of the same samples. Detection limit and sensitivity to the current Swiss exemption limit are calculated. Comparison with radiochemical analysis shows inconsistency for the sensitivity for only two samples, most likely due to underestimated uncertainties of the GEMPix analysis. An operative test phase of this technique is already planned at CERN.

  19. Passive Samplers for Investigations of Air Quality: Method Description, Implementation, and Comparison to Alternative Sampling Methods

    EPA Science Inventory

    This Paper covers the basics of passive sampler design, compares passive samplers to conventional methods of air sampling, and discusses considerations when implementing a passive sampling program. The Paper also discusses field sampling and sample analysis considerations to ensu...

  20. Method and apparatus for imaging a sample on a device

    DOEpatents

    Trulson, Mark; Stern, David; Fiekowsky, Peter; Rava, Richard; Walton, Ian; Fodor, Stephen P. A.

    2001-01-01

    A method and apparatus for imaging a sample are provided. An electromagnetic radiation source generates excitation radiation which is sized by excitation optics to a line. The line is directed at a sample resting on a support and excites a plurality of regions on the sample. Collection optics collect response radiation reflected from the sample I and image the reflected radiation. A detector senses the reflected radiation and is positioned to permit discrimination between radiation reflected from a certain focal plane in the sample and certain other planes within the sample.

  1. Engineering Study of 500 ML Sample Bottle Transportation Methods

    SciTech Connect

    BOGER, R.M.

    1999-08-25

    This engineering study reviews and evaluates all available methods for transportation of 500-mL grab sample bottles, reviews and evaluates transportation requirements and schedules and analyzes and recommends the most cost-effective method for transporting 500-mL grab sample bottles.

  2. 40 CFR Appendix I to Part 261 - Representative Sampling Methods

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Appendix I to Part 261 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) IDENTIFICATION AND LISTING OF HAZARDOUS WASTE Pt. 261, App. I Appendix I to Part 261—Representative Sampling Methods The methods and equipment used for sampling waste materials will vary with...

  3. GROUND WATER PURGING AND SAMPLING METHODS: HISTORY VS. HYSTERIA

    EPA Science Inventory

    It has been over 10 years since the low-flow ground water purging and sampling method was initially reported in the literature. The method grew from the recognition that well purging was necessary to collect representative samples, bailers could not achieve well purging, and high...

  4. Evaluation of Common Methods for Sampling Invertebrate Pollinator Assemblages: Net Sampling Out-Perform Pan Traps

    PubMed Central

    Popic, Tony J.; Davila, Yvonne C.; Wardle, Glenda M.

    2013-01-01

    Methods for sampling ecological assemblages strive to be efficient, repeatable, and representative. Unknowingly, common methods may be limited in terms of revealing species function and so of less value for comparative studies. The global decline in pollination services has stimulated surveys of flower-visiting invertebrates, using pan traps and net sampling. We explore the relative merits of these two methods in terms of species discovery, quantifying abundance, function, and composition, and responses of species to changing floral resources. Using a spatially-nested design we sampled across a 5000 km2 area of arid grasslands, including 432 hours of net sampling and 1296 pan trap-days, between June 2010 and July 2011. Net sampling yielded 22% more species and 30% higher abundance than pan traps, and better reflected the spatio-temporal variation of floral resources. Species composition differed significantly between methods; from 436 total species, 25% were sampled by both methods, 50% only by nets, and the remaining 25% only by pans. Apart from being less comprehensive, if pan traps do not sample flower-visitors, the link to pollination is questionable. By contrast, net sampling functionally linked species to pollination through behavioural observations of flower-visitation interaction frequency. Netted specimens are also necessary for evidence of pollen transport. Benefits of net-based sampling outweighed minor differences in overall sampling effort. As pan traps and net sampling methods are not equivalent for sampling invertebrate-flower interactions, we recommend net sampling of invertebrate pollinator assemblages, especially if datasets are intended to document declines in pollination and guide measures to retain this important ecosystem service. PMID:23799127

  5. Evaluation of common methods for sampling invertebrate pollinator assemblages: net sampling out-perform pan traps.

    PubMed

    Popic, Tony J; Davila, Yvonne C; Wardle, Glenda M

    2013-01-01

    Methods for sampling ecological assemblages strive to be efficient, repeatable, and representative. Unknowingly, common methods may be limited in terms of revealing species function and so of less value for comparative studies. The global decline in pollination services has stimulated surveys of flower-visiting invertebrates, using pan traps and net sampling. We explore the relative merits of these two methods in terms of species discovery, quantifying abundance, function, and composition, and responses of species to changing floral resources. Using a spatially-nested design we sampled across a 5000 km(2) area of arid grasslands, including 432 hours of net sampling and 1296 pan trap-days, between June 2010 and July 2011. Net sampling yielded 22% more species and 30% higher abundance than pan traps, and better reflected the spatio-temporal variation of floral resources. Species composition differed significantly between methods; from 436 total species, 25% were sampled by both methods, 50% only by nets, and the remaining 25% only by pans. Apart from being less comprehensive, if pan traps do not sample flower-visitors, the link to pollination is questionable. By contrast, net sampling functionally linked species to pollination through behavioural observations of flower-visitation interaction frequency. Netted specimens are also necessary for evidence of pollen transport. Benefits of net-based sampling outweighed minor differences in overall sampling effort. As pan traps and net sampling methods are not equivalent for sampling invertebrate-flower interactions, we recommend net sampling of invertebrate pollinator assemblages, especially if datasets are intended to document declines in pollination and guide measures to retain this important ecosystem service.

  6. Evaluating Composite Sampling Methods of Bacillus spores at Low Concentrations

    SciTech Connect

    Hess, Becky M.; Amidan, Brett G.; Anderson, Kevin K.; Hutchison, Janine R.

    2016-10-13

    Restoring facility operations after the 2001 Amerithrax attacks took over three months to complete, highlighting the need to reduce remediation time. The most time intensive tasks were environmental sampling and sample analyses. Composite sampling allows disparate samples to be combined, with only a single analysis needed, making it a promising method to reduce response times. We developed a statistical experimental design to test three different composite sampling methods: 1) single medium single pass composite: a single cellulose sponge samples multiple coupons; 2) single medium multi-pass composite: a single cellulose sponge is used to sample multiple coupons; and 3) multi-medium post-sample composite: a single cellulose sponge samples a single surface, and then multiple sponges are combined during sample extraction. Five spore concentrations of Bacillus atrophaeus Nakamura spores were tested; concentrations ranged from 5 to 100 CFU/coupon (0.00775 to 0.155CFU/cm2, respectively). Study variables included four clean surface materials (stainless steel, vinyl tile, ceramic tile, and painted wallboard) and three grime coated/dirty materials (stainless steel, vinyl tile, and ceramic tile). Analysis of variance for the clean study showed two significant factors: composite method (p-value < 0.0001) and coupon material (p-value = 0.0008). Recovery efficiency (RE) was higher overall using the post-sample composite (PSC) method compared to single medium composite from both clean and grime coated materials. RE with the PSC method for concentrations tested (10 to 100 CFU/coupon) was similar for ceramic tile, painted wall board, and stainless steel for clean materials. RE was lowest for vinyl tile with both composite methods. Statistical tests for the dirty study showed RE was significantly higher for vinyl and stainless steel materials, but significantly lower for ceramic tile. These results suggest post-sample compositing can be used to reduce sample analysis time when

  7. A Mixed Methods Sampling Methodology for a Multisite Case Study

    ERIC Educational Resources Information Center

    Sharp, Julia L.; Mobley, Catherine; Hammond, Cathy; Withington, Cairen; Drew, Sam; Stringfield, Sam; Stipanovic, Natalie

    2012-01-01

    The flexibility of mixed methods research strategies makes such approaches especially suitable for multisite case studies. Yet the utilization of mixed methods to select sites for these studies is rarely reported. The authors describe their pragmatic mixed methods approach to select a sample for their multisite mixed methods case study of a…

  8. [Respondent-Driven Sampling: a new sampling method to study visible and hidden populations].

    PubMed

    Mantecón, Alejandro; Juan, Montse; Calafat, Amador; Becoña, Elisardo; Román, Encarna

    2008-01-01

    The paper introduces a variant of chain-referral sampling: respondent-driven sampling (RDS). This sampling method shows that methods based on network analysis can be combined with the statistical validity of standard probability sampling methods. In this sense, RDS appears to be a mathematical improvement of snowball sampling oriented to the study of hidden populations. However, we try to prove its validity with populations that are not within a sampling frame but can nonetheless be contacted without difficulty. The basics of RDS are explained through our research on young people (aged 14 to 25) who go clubbing, consume alcohol and other drugs, and have sex. Fieldwork was carried out between May and July 2007 in three Spanish regions: Baleares, Galicia and Comunidad Valenciana. The presentation of the study shows the utility of this type of sampling when the population is accessible but there is a difficulty deriving from the lack of a sampling frame. However, the sample obtained is not a random representative one in statistical terms of the target population. It must be acknowledged that the final sample is representative of a 'pseudo-population' that approximates to the target population but is not identical to it.

  9. Cloud condensation nuclei activity and droplet activation kinetics of wet processed regional dust samples and minerals

    NASA Astrophysics Data System (ADS)

    Kumar, P.; Sokolik, I. N.; Nenes, A.

    2011-08-01

    This study reports laboratory measurements of particle size distributions, cloud condensation nuclei (CCN) activity, and droplet activation kinetics of wet generated aerosols from clays, calcite, quartz, and desert soil samples from Northern Africa, East Asia/China, and Northern America. The dependence of critical supersaturation, sc, on particle dry diameter, Ddry, is used to characterize particle-water interactions and assess the ability of Frenkel-Halsey-Hill adsorption activation theory (FHH-AT) and Köhler theory (KT) to describe the CCN activity of the considered samples. Wet generated regional dust samples produce unimodal size distributions with particle sizes as small as 40 nm, CCN activation consistent with KT, and exhibit hygroscopicity similar to inorganic salts. Wet generated clays and minerals produce a bimodal size distribution; the CCN activity of the smaller mode is consistent with KT, while the larger mode is less hydrophilic, follows activation by FHH-AT, and displays almost identical CCN activity to dry generated dust. Ion Chromatography (IC) analysis performed on regional dust samples indicates a soluble fraction that cannot explain the CCN activity of dry or wet generated dust. A mass balance and hygroscopicity closure suggests that the small amount of ions (from low solubility compounds like calcite) present in the dry dust dissolve in the aqueous suspension during the wet generation process and give rise to the observed small hygroscopic mode. Overall these results identify an artifact that may question the atmospheric relevance of dust CCN activity studies using the wet generation method. Based on the method of threshold droplet growth analysis, wet generated mineral aerosols display similar activation kinetics compared to ammonium sulfate calibration aerosol. Finally, a unified CCN activity framework that accounts for concurrent effects of solute and adsorption is developed to describe the CCN activity of aged or hygroscopic dusts.

  10. Method based on bioinspired sample improves autofocusing performances

    NASA Astrophysics Data System (ADS)

    Cao, Jie; Cheng, Yang; Wang, Peng; Peng, Yuxin; Zhang, Kaiyu; Wu, Leina; Xia, Wenze; Yu, Haoyong

    2016-10-01

    In order to solve the issue between fast autofocusing speed and high volume data processing, we propose a bioinspired sampling method based on a retina-like structure. We develop retina-like models and analyze the division of sampling structure. The optimal retina-like sample is obtained by analyzing two key parameters (sectors and radius of blind area) of the retina-like structure through experiments. Under the typical autofocus functions, including Vollath-4, Laplacian, Tenengrad, spatial frequency, and sum-modified-Laplacian (SML), we carry out comparative experiments of computation time based on the retina-like sample and a traditional uniform sample. The results show that the retina-like sample is suitable for those autofocus functions. Based on the autofocus function of SML, the average time of uniform sample decreases from 3.5 to 2.1 s for the retina-like sample.

  11. Method for using polarization gating to measure a scattering sample

    DOEpatents

    Baba, Justin S.

    2015-08-04

    Described herein are systems, devices, and methods facilitating optical characterization of scattering samples. A polarized optical beam can be directed to pass through a sample to be tested. The optical beam exiting the sample can then be analyzed to determine its degree of polarization, from which other properties of the sample can be determined. In some cases, an apparatus can include a source of an optical beam, an input polarizer, a sample, an output polarizer, and a photodetector. In some cases, a signal from a photodetector can be processed through attenuation, variable offset, and variable gain.

  12. Sampling and sample preparation methods for determining concentrations of mycotoxins in foods and feeds.

    PubMed

    2012-01-01

    Sample variation is often the largest error in determining concentrations of mycotoxins in food commodities. The worldwide safety evaluation of mycotoxins requires sampling plans that give acceptably accurate values for the levels of contamination in specific batches or lots of a commodity. Mycotoxin concentrations show a skewed or uneven distribution in foods and feeds, especially in whole kernels (or nuts), so it is extremely difficult to collect a sample that accurately represents the mean batch concentration. Sample variance studies and sampling plans have been published for select mycotoxins such as aflatoxin, fumonisin, and deoxynivalenol, emphasizing the importance of sample selection, sample size, and the number of incremental samples. For meaningful data to be generated from surveillance studies, representative samples should be collected from carefully selected populations (batches or lots) of food that, in turn, should be representative of clearly defined locations (e.g. a country, a region within a country). Although sampling variability is unavoidable, it is essential that the precision of the sampling plan be clearly defined and be considered acceptable by those responsible for interpreting and reporting the surveillance data. The factors influencing variability are detailed here, with reference to both major mycotoxins and major commodities. Sampling of large bag stacks, bulk shipments, and domestic supplies are all discussed. Sampling plans currently accepted in international trade are outlined. Acceptance sampling plans and the variabilities that affect operating characteristic curves of such plans are also detailed. The constraints and issues related to the sampling of harvested crops within subsistence farming areas are also discussed in this chapter, as are the essential rules of sample labelling and storage. The chapter concludes with a short section on sample preparation methods.

  13. [Recent advances in sample preparation methods of plant hormones].

    PubMed

    Wu, Qian; Wang, Lus; Wu, Dapeng; Duan, Chunfeng; Guan, Yafeng

    2014-04-01

    Plant hormones are a group of naturally occurring trace substances which play a crucial role in controlling the plant development, growth and environment response. With the development of the chromatography and mass spectroscopy technique, chromatographic analytical method has become a widely used way for plant hormone analysis. Among the steps of chromatographic analysis, sample preparation is undoubtedly the most vital one. Thus, a highly selective and efficient sample preparation method is critical for accurate identification and quantification of phytohormones. For the three major kinds of plant hormones including acidic plant hormones & basic plant hormones, brassinosteroids and plant polypeptides, the sample preparation methods are reviewed in sequence especially the recently developed methods. The review includes novel methods, devices, extractive materials and derivative reagents for sample preparation of phytohormones analysis. Especially, some related works of our group are included. At last, the future developments in this field are also prospected.

  14. Interval sampling methods and measurement error: a computer simulation.

    PubMed

    Wirth, Oliver; Slaven, James; Taylor, Matthew A

    2014-01-01

    A simulation study was conducted to provide a more thorough account of measurement error associated with interval sampling methods. A computer program simulated the application of momentary time sampling, partial-interval recording, and whole-interval recording methods on target events randomly distributed across an observation period. The simulation yielded measures of error for multiple combinations of observation period, interval duration, event duration, and cumulative event duration. The simulations were conducted up to 100 times to yield measures of error variability. Although the present simulation confirmed some previously reported characteristics of interval sampling methods, it also revealed many new findings that pertain to each method's inherent strengths and weaknesses. The analysis and resulting error tables can help guide the selection of the most appropriate sampling method for observation-based behavioral assessments.

  15. [Weighted estimation methods for multistage sampling survey data].

    PubMed

    Hou, Xiao-Yan; Wei, Yong-Yue; Chen, Feng

    2009-06-01

    Multistage sampling techniques are widely applied in the cross-sectional study of epidemiology, while methods based on independent assumption are still used to analyze such complex survey data. This paper aims to introduce the application of weighted estimation methods for the complex survey data. A brief overview of basic theory is described, and then a practical analysis is illustrated to apply to the weighted estimation algorithm in a stratified two-stage clustered sampling data. For multistage sampling survey data, weighted estimation method can be used to obtain unbiased point estimation and more reasonable variance estimation, and so make proper statistical inference by correcting the clustering, stratification and unequal probability effects.

  16. A random spatial sampling method in a rural developing nation

    PubMed Central

    2014-01-01

    Background Nonrandom sampling of populations in developing nations has limitations and can inaccurately estimate health phenomena, especially among hard-to-reach populations such as rural residents. However, random sampling of rural populations in developing nations can be challenged by incomplete enumeration of the base population. Methods We describe a stratified random sampling method using geographical information system (GIS) software and global positioning system (GPS) technology for application in a health survey in a rural region of Guatemala, as well as a qualitative study of the enumeration process. Results This method offers an alternative sampling technique that could reduce opportunities for bias in household selection compared to cluster methods. However, its use is subject to issues surrounding survey preparation, technological limitations and in-the-field household selection. Application of this method in remote areas will raise challenges surrounding the boundary delineation process, use and translation of satellite imagery between GIS and GPS, and household selection at each survey point in varying field conditions. This method favors household selection in denser urban areas and in new residential developments. Conclusions Random spatial sampling methodology can be used to survey a random sample of population in a remote region of a developing nation. Although this method should be further validated and compared with more established methods to determine its utility in social survey applications, it shows promise for use in developing nations with resource-challenged environments where detailed geographic and human census data are less available. PMID:24716473

  17. Integration of sample analysis method (SAM) for polychlorinated biphenyls

    SciTech Connect

    Monagle, M.; Johnson, R.C.

    1996-05-01

    A completely integrated Sample Analysis Method (SAM) has been tested as part of the Contaminant Analysis Automation program. The SAM system was tested for polychlorinated biphenyl samples using five Standard Laboratory Modules{trademark}: two Soxtec{trademark} modules, a high volume concentrator module, a generic materials handling module, and the gas chromatographic module. With over 300 samples completed within the first phase of the validation, recovery and precision data were comparable to manual methods. Based on experience derived from the first evaluation of the automated system, efforts are underway to improve sample recoveries and integrate a sample cleanup procedure. In addition, initial work in automating the extraction of semivolatile samples using this system will also be discussed.

  18. Method and sample spinning apparatus for measuring the NMR spectrum of an orientationally disordered sample

    DOEpatents

    Pines, Alexander; Samoson, Ago

    1990-01-01

    An improved NMR apparatus and method are described which substantially improve the resolution of NMR measurements made on powdered or amorphous or otherwise orientationally disordered samples. The apparatus spins the sample about an axis. The angle of the axis is mechanically varied such that the time average of two or more Legendre polynomials are zero.

  19. Methods for collection and analysis of water samples

    USGS Publications Warehouse

    Rainwater, Frank Hays; Thatcher, Leland Lincoln

    1960-01-01

    This manual contains methods used by the U.S. Geological Survey to collect, preserve, and analyze water samples. Throughout, the emphasis is on obtaining analytical results that accurately describe the chemical composition of the water in situ. Among the topics discussed are selection of sampling sites, frequency of sampling, field equipment, preservatives and fixatives, analytical techniques of water analysis, and instruments. Seventy-seven laboratory and field procedures are given for determining fifty-three water properties.

  20. Optimized method for dissolved hydrogen sampling in groundwater.

    PubMed

    Alter, Marcus D; Steiof, Martin

    2005-06-01

    Dissolved hydrogen concentrations are used to characterize redox conditions of contaminated aquifers. The currently accepted and recommended bubble strip method for hydrogen sampling (Wiedemeier et al., 1998) requires relatively long sampling times and immediate field analysis. In this study we present methods for optimized sampling and for sample storage. The bubble strip sampling method was examined for various flow rates, bubble sizes (headspace volume in the sampling bulb) and two different H2 concentrations. The results were compared to a theoretical equilibration model. Turbulent flow in the sampling bulb was optimized for gas transfer by reducing the inlet diameter. Extraction with a 5 mL headspace volume and flow rates higher than 100 mL/min resulted in 95-100% equilibrium within 10-15 min. In order to investigate the storage of samples from the gas sampling bulb gas samples were kept in headspace vials for varying periods. Hydrogen samples (4.5 ppmv, corresponding to 3.5 nM in liquid phase) could be stored up to 48 h and 72 h with a recovery rate of 100.1+/-2.6% and 94.6+/-3.2%, respectively. These results are promising and prove the possibility of storage for 2-3 days before laboratory analysis. The optimized method was tested at a field site contaminated with chlorinated solvents. Duplicate gas samples were stored in headspace vials and analyzed after 24 h. Concentrations were measured in the range of 2.5-8.0 nM corresponding to known concentrations in reduced aquifers.

  1. Capillary microextraction: A new method for sampling methamphetamine vapour.

    PubMed

    Nair, M V; Miskelly, G M

    2016-11-01

    Clandestine laboratories pose a serious health risk to first responders, investigators, decontamination companies, and the public who may be inadvertently exposed to methamphetamine and other chemicals used in its manufacture. Therefore there is an urgent need for reliable methods to detect and measure methamphetamine at such sites. The most common method for determining methamphetamine contamination at former clandestine laboratory sites is selected surface wipe sampling, followed by analysis with gas chromatography-mass spectrometry (GC-MS). We are investigating the use of sampling for methamphetamine vapour to complement such wipe sampling. In this study, we report the use of capillary microextraction (CME) devices for sampling airborne methamphetamine, and compare their sampling efficiency with a previously reported dynamic SPME method. The CME devices consisted of PDMS-coated glass filter strips inside a glass tube. The devices were used to dynamically sample methamphetamine vapour in the range of 0.42-4.2μgm(-3), generated by a custom-built vapour dosing system, for 1-15min, and methamphetamine was analysed using a GC-MS fitted with a ChromatoProbe thermal desorption unit. The devices showed good reproducibility (RSD<15%), and a curvilinear pre-equilibrium relationship between sampling times and peak area, which can be utilised for calibration. Under identical sampling conditions, the CME devices were approximately 30 times more sensitive than the dynamic SPME method. The CME devices could be stored for up to 3days after sampling prior to analysis. Consecutive sampling of methamphetamine and its isotopic substitute, d-9 methamphetamine showed no competitive displacement. This suggests that CME devices, pre-loaded with an internal standard, could be a feasible method for sampling airborne methamphetamine at former clandestine laboratories.

  2. Demonstration Report for Visual Sample Plan (VSP) Verification Sampling Methods at the Navy/DRI Site

    DTIC Science & Technology

    2011-08-01

    STATISTICAL VERIFICATION AND REMEDIATION SAMPLING METHODS (200837) August 2011 Pacific Northwest National Laboratory Brent Pulsipher...17. LIMIT ATIOH OF 1S. NUMSER 19~. NAME OS: RESPONSI’SLE PERSON ABSTRACT o• Brent Pulsipher ... ...., .. •. ’ · ’"" .... PAG .’ES uu 93 19b... Statistical Verification Sampling Methods in VSP ii August 2011 6.2.1  Transect Survey Design and Parameter Settings

  3. Nominal Weights Mean Equating: A Method for Very Small Samples

    ERIC Educational Resources Information Center

    Babcock, Ben; Albano, Anthony; Raymond, Mark

    2012-01-01

    The authors introduced nominal weights mean equating, a simplified version of Tucker equating, as an alternative for dealing with very small samples. The authors then conducted three simulation studies to compare nominal weights mean equating to six other equating methods under the nonequivalent groups anchor test design with sample sizes of 20,…

  4. Field Evaluation of Personal Sampling Methods for Multiple Bioaerosols

    PubMed Central

    Wang, Chi-Hsun; Chen, Bean T.; Han, Bor-Cheng; Liu, Andrew Chi-Yeu; Hung, Po-Chen; Chen, Chih-Yong; Chao, Hsing Jasmine

    2015-01-01

    Ambient bioaerosols are ubiquitous in the daily environment and can affect health in various ways. However, few studies have been conducted to comprehensively evaluate personal bioaerosol exposure in occupational and indoor environments because of the complex composition of bioaerosols and the lack of standardized sampling/analysis methods. We conducted a study to determine the most efficient collection/analysis method for the personal exposure assessment of multiple bioaerosols. The sampling efficiencies of three filters and four samplers were compared. According to our results, polycarbonate (PC) filters had the highest relative efficiency, particularly for bacteria. Side-by-side sampling was conducted to evaluate the three filter samplers (with PC filters) and the NIOSH Personal Bioaerosol Cyclone Sampler. According to the results, the Button Aerosol Sampler and the IOM Inhalable Dust Sampler had the highest relative efficiencies for fungi and bacteria, followed by the NIOSH sampler. Personal sampling was performed in a pig farm to assess occupational bioaerosol exposure and to evaluate the sampling/analysis methods. The Button and IOM samplers yielded a similar performance for personal bioaerosol sampling at the pig farm. However, the Button sampler is more likely to be clogged at high airborne dust concentrations because of its higher flow rate (4 L/min). Therefore, the IOM sampler is a more appropriate choice for performing personal sampling in environments with high dust levels. In summary, the Button and IOM samplers with PC filters are efficient sampling/analysis methods for the personal exposure assessment of multiple bioaerosols. PMID:25799419

  5. Passive sampling methods for contaminated sediments: Risk assessment and management

    PubMed Central

    Greenberg, Marc S; Chapman, Peter M; Allan, Ian J; Anderson, Kim A; Apitz, Sabine E; Beegan, Chris; Bridges, Todd S; Brown, Steve S; Cargill, John G; McCulloch, Megan C; Menzie, Charles A; Shine, James P; Parkerton, Thomas F

    2014-01-01

    This paper details how activity-based passive sampling methods (PSMs), which provide information on bioavailability in terms of freely dissolved contaminant concentrations (Cfree), can be used to better inform risk management decision making at multiple points in the process of assessing and managing contaminated sediment sites. PSMs can increase certainty in site investigation and management, because Cfree is a better predictor of bioavailability than total bulk sediment concentration (Ctotal) for 4 key endpoints included in conceptual site models (benthic organism toxicity, bioaccumulation, sediment flux, and water column exposures). The use of passive sampling devices (PSDs) presents challenges with respect to representative sampling for estimating average concentrations and other metrics relevant for exposure and risk assessment. These challenges can be addressed by designing studies that account for sources of variation associated with PSMs and considering appropriate spatial scales to meet study objectives. Possible applications of PSMs include: quantifying spatial and temporal trends in bioavailable contaminants, identifying and evaluating contaminant source contributions, calibrating site-specific models, and, improving weight-of-evidence based decision frameworks. PSM data can be used to assist in delineating sediment management zones based on likelihood of exposure effects, monitor remedy effectiveness, and, evaluate risk reduction after sediment treatment, disposal, or beneficial reuse after management actions. Examples are provided illustrating why PSMs and freely dissolved contaminant concentrations (Cfree) should be incorporated into contaminated sediment investigations and study designs to better focus on and understand contaminant bioavailability, more accurately estimate exposure to sediment-associated contaminants, and better inform risk management decisions. Research and communication needs for encouraging broader use are discussed. Integr

  6. A cryopreservation method for Pasteurella multocida from wetland samples

    USGS Publications Warehouse

    Moore, Melody K.; Shadduck, D.J.; Goldberg, D.R.; Samuel, M.D.

    1998-01-01

    A cryopreservation method and improved isolation techniques for detection of Pasteurella multocida from wetland samples were developed. Wetland water samples were collected in the field, diluted in dimethyl sulfoxide (DMSO, final concentration 10%), and frozen at -180 C in a liquid nitrogen vapor shipper. Frozen samples were transported to the laboratory where they were subsequently thawed and processed in Pasteurella multocida selective broth (PMSB) to isolate P. multocida. This method allowed for consistent isolation of 2 to 18 organisms/ml from water seeded with known concentrations of P. multocida. The method compared favorably with the standard mouse inoculation method and allowed for preservation of the samples until they could be processed in the laboratory.

  7. Probability Sampling Method for a Hidden Population Using Respondent-Driven Sampling: Simulation for Cancer Survivors.

    PubMed

    Jung, Minsoo

    2015-01-01

    When there is no sampling frame within a certain group or the group is concerned that making its population public would bring social stigma, we say the population is hidden. It is difficult to approach this kind of population survey-methodologically because the response rate is low and its members are not quite honest with their responses when probability sampling is used. The only alternative known to address the problems caused by previous methods such as snowball sampling is respondent-driven sampling (RDS), which was developed by Heckathorn and his colleagues. RDS is based on a Markov chain, and uses the social network information of the respondent. This characteristic allows for probability sampling when we survey a hidden population. We verified through computer simulation whether RDS can be used on a hidden population of cancer survivors. According to the simulation results of this thesis, the chain-referral sampling of RDS tends to minimize as the sample gets bigger, and it becomes stabilized as the wave progresses. Therefore, it shows that the final sample information can be completely independent from the initial seeds if a certain level of sample size is secured even if the initial seeds were selected through convenient sampling. Thus, RDS can be considered as an alternative which can improve upon both key informant sampling and ethnographic surveys, and it needs to be utilized for various cases domestically as well.

  8. Quality of plasma sampled by different methods for multiple blood sampling in mice.

    PubMed

    Christensen, S D; Mikkelsen, L F; Fels, J J; Bodvarsdóttir, T B; Hansen, A K

    2009-01-01

    For oral glucose tolerance test (OGTT) in mice, multiple blood samples need to be taken within a few hours from conscious mice. Today, a number of essential parameters may be analysed on very small amounts of plasma, thus reducing the number of animals to be used. It is, however, crucial to obtain high-quality plasma or serum in order to avoid increased data variation and thereby increased group sizes. The aim of this study was to find the most valid and reproducible method for withdrawal of blood samples when performing OGTT. Four methods, i.e. amputation of the tail tip, lateral tail incision, puncture of the tail tip and periorbital puncture, were selected for testing at 21 degrees C and 30 degrees C after a pilot study. For each method, four blood samples were drawn from C57BL/6 mice at 30 min intervals. The presence of clots was registered, haemolysis was monitored spectrophotometrically at 430 nm, and it was noted whether it was possible to achieve 30-50 microL blood. Furthermore, a small amount of extra blood was sampled before and after the four samplings for testing of whether the sampling induced a blood glucose change over the 90 min test period. All methods resulted in acceptable amounts of plasma. Clots were observed in a sparse number of samples with no significant differences between the methods. Periorbital puncture did not lead to any haemolysed samples at all, and lateral tail incision resulted in only a few haemolysed samples, while puncture or amputation of the tail tip induced haemolysis in a significant number of samples. All methods, except for puncture of the tail tip, influenced blood glucose. Periorbital puncture resulted in a dramatic increase in blood glucose of up to 3.5 mmol/L indicating that it is stressful. Although lateral tail incision also had some impact on blood glucose, it seems to be the method of choice for OGTT, as it is likely to produce a clot-free non-haemolysed sample, while periorbital sampling, although producing a

  9. A quantitative sampling method for Oncomelania quadrasi by filter paper.

    PubMed

    Tanaka, H; Santos, M J; Matsuda, H; Yasuraoka, K; Santos, A T

    1975-08-01

    Filter paper was found to attract Oncomelania quadrasi in waters the same way as fallen dried banana leaves, although less number of other species of snails was collected on the former than on the latter. Snails were collected in limited areas using a tube (85 cm2 area at cross-section) and a filter paper (20 X 20 CM) samplers. The sheet of filter paper was placed close to the spot where a tube sample was taken, and recovered after 24 hours. At each sampling, 30 samples were taken by each method in an area and sampling was made four times. The correlation of the number of snails collected by the tube and that by filter paper was studied. The ratio of the snail counts by the tube sampler to those by the filter paper was 1.18. A loose correlation was observed between snail counts of both methods as shown by the correlation coefficient r = 0.6502. The formulas for the regression line were Y = 0.77 X + 1.6 and X = 0.55 Y + 1.35 for 3 experiments where Y is the number of snails collected by tube sampling and X is the number of snails collected in the sheet of filter paper. The type of snail distribution was studied in the 30 samples taken by each method and this was observed to be nearly the same in both sampling methods. All sampling data were found to fit the negative binomial distribution with the values of the constant k varying very much from 0.5775 to 5.9186 in (q -- p)-k. In each experiment, the constant k was always larger in tube sampling than in filter paper sampling. This indicates that the uneven distribution of snails on the soil surface becomes more conspicuous by the filter paper sampling.

  10. Soil separator and sampler and method of sampling

    SciTech Connect

    O'Brien, Barry H; Ritter, Paul D

    2010-02-16

    A soil sampler includes a fluidized bed for receiving a soil sample. The fluidized bed may be in communication with a vacuum for drawing air through the fluidized bed and suspending particulate matter of the soil sample in the air. In a method of sampling, the air may be drawn across a filter, separating the particulate matter. Optionally, a baffle or a cyclone may be included within the fluidized bed for disentrainment, or dedusting, so only the finest particulate matter, including asbestos, will be trapped on the filter. The filter may be removable, and may be tested to determine the content of asbestos and other hazardous particulate matter in the soil sample.

  11. Method and apparatus for imaging a sample on a device

    DOEpatents

    Trulson, Mark; Stern, David; Fiekowsky, Peter; Rava, Richard; Walton, Ian; Fodor, Stephen P. A.

    1996-01-01

    The present invention provides methods and systems for detecting a labeled marker on a sample located on a support. The imaging system comprises a body for immobilizing the support, an excitation radiation source and excitation optics to generate and direct the excitation radiation at the sample. In response, labeled material on the sample emits radiation which has a wavelength that is different from the excitation wavelength, which radiation is collected by collection optics and imaged onto a detector which generates an image of the sample.

  12. System and method for measuring fluorescence of a sample

    DOEpatents

    Riot, Vincent J

    2015-03-24

    The present disclosure provides a system and a method for measuring fluorescence of a sample. The sample may be a polymerase-chain-reaction (PCR) array, a loop-mediated-isothermal amplification array, etc. LEDs are used to excite the sample, and a photodiode is used to collect the sample's fluorescence. An electronic offset signal is used to reduce the effects of background fluorescence and the noises from the measurement system. An integrator integrates the difference between the output of the photodiode and the electronic offset signal over a given period of time. The resulting integral is then converted into digital domain for further processing and storage.

  13. Neutron activation analysis for antimetabolites. [in food samples

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Determination of metal ion contaminants in food samples is studied. A weighed quantity of each sample was digested in a concentrated mixture of nitric, hydrochloric and perchloric acids to affect complete solution of the food products. The samples were diluted with water and the pH adjusted according to the specific analysis performed. The samples were analyzed by neutron activation analysis, polarography, and atomic absorption spectrophotometry. The solid food samples were also analyzed by neutron activation analysis for increased sensitivity and lower levels of detectability. The results are presented in tabular form.

  14. A quantitative evaluation of two methods for preserving hair samples

    USGS Publications Warehouse

    Roon, David A.; Waits, L.P.; Kendall, K.C.

    2003-01-01

    Hair samples are an increasingly important DNA source for wildlife studies, yet optimal storage methods and DNA degradation rates have not been rigorously evaluated. We tested amplification success rates over a one-year storage period for DNA extracted from brown bear (Ursus arctos) hair samples preserved using silica desiccation and -20C freezing. For three nuclear DNA microsatellites, success rates decreased significantly after a six-month time point, regardless of storage method. For a 1000 bp mitochondrial fragment, a similar decrease occurred after a two-week time point. Minimizing delays between collection and DNA extraction will maximize success rates for hair-based noninvasive genetic sampling projects.

  15. Convenient mounting method for electrical measurements of thin samples

    NASA Technical Reports Server (NTRS)

    Matus, L. G.; Summers, R. L.

    1986-01-01

    A method for mounting thin samples for electrical measurements is described. The technique is based on a vacuum chuck concept in which the vacuum chuck simultaneously holds the sample and established electrical contact. The mounting plate is composed of a glass-ceramic insulating material and the surfaces of the plate and vacuum chuck are polished. The operation of the vacuum chuck is examined. The contacts on the sample and mounting plate, which are sputter-deposited through metal masks, are analyzed. The mounting method was utilized for van der Pauw measurements.

  16. Tests of a comparative method of dating plutonium samples

    NASA Astrophysics Data System (ADS)

    West, D.

    1987-04-01

    Tests of a comparative method of dating plutonium samples have been carried out using 241Pu in aqueous solution. The six samples were of known ages (between 0.25 and 15 yr) and with one exception the measured ages, using particular samples as standards, agreed with the stated ages. In one case the agreement was beter than 1% in age. Mixed-oxide fuel pins were also intercompared. In this case it was with some difficulty that a sample of known age was obtaine. Comparison using this sample and an older one gave the same value (within ±1%) for the separation date of the unknown sample on three occasions over a three year period.

  17. Evaluating Composite Sampling Methods of Bacillus Spores at Low Concentrations

    PubMed Central

    Hess, Becky M.; Amidan, Brett G.; Anderson, Kevin K.; Hutchison, Janine R.

    2016-01-01

    Restoring all facility operations after the 2001 Amerithrax attacks took years to complete, highlighting the need to reduce remediation time. Some of the most time intensive tasks were environmental sampling and sample analyses. Composite sampling allows disparate samples to be combined, with only a single analysis needed, making it a promising method to reduce response times. We developed a statistical experimental design to test three different composite sampling methods: 1) single medium single pass composite (SM-SPC): a single cellulose sponge samples multiple coupons with a single pass across each coupon; 2) single medium multi-pass composite: a single cellulose sponge samples multiple coupons with multiple passes across each coupon (SM-MPC); and 3) multi-medium post-sample composite (MM-MPC): a single cellulose sponge samples a single surface, and then multiple sponges are combined during sample extraction. Five spore concentrations of Bacillus atrophaeus Nakamura spores were tested; concentrations ranged from 5 to 100 CFU/coupon (0.00775 to 0.155 CFU/cm2). Study variables included four clean surface materials (stainless steel, vinyl tile, ceramic tile, and painted dry wallboard) and three grime coated/dirty materials (stainless steel, vinyl tile, and ceramic tile). Analysis of variance for the clean study showed two significant factors: composite method (p< 0.0001) and coupon material (p = 0.0006). Recovery efficiency (RE) was higher overall using the MM-MPC method compared to the SM-SPC and SM-MPC methods. RE with the MM-MPC method for concentrations tested (10 to 100 CFU/coupon) was similar for ceramic tile, dry wall, and stainless steel for clean materials. RE was lowest for vinyl tile with both composite methods. Statistical tests for the dirty study showed RE was significantly higher for vinyl and stainless steel materials, but lower for ceramic tile. These results suggest post-sample compositing can be used to reduce sample analysis time when

  18. An easy method for the determination of active concentrations of cholinesterase reactivators in blood samples: Application to the efficacy assessment of non quaternary reactivators compared to HI-6 and pralidoxime in VX-poisoned mice.

    PubMed

    Calas, André-Guilhem; Dias, José; Rousseau, Catherine; Arboléas, Mélanie; Touvrey-Loiodice, Mélanie; Mercey, Guillaume; Jean, Ludovic; Renard, Pierre-Yves; Nachon, Florian

    2017-04-01

    Organophosphorus nerve agents, like VX, are highly toxic due to their strong inhibition potency against acetylcholinesterase (AChE). AChE inhibited by VX can be reactivated using powerful nucleophilic molecules, most commonly oximes, which are one major component of the emergency treatment in case of nerve agent intoxication. We present here a comparative in vivo study on Swiss mice of four reactivators: HI-6, pralidoxime and two uncharged derivatives of 3-hydroxy-2-pyridinaldoxime that should more easily cross the blood-brain barrier and display a significant central nervous system activity. The reactivability kinetic profile of the oximes is established following intraperitoneal injection in healthy mice, using an original and fast enzymatic method based on the reactivation potential of oxime-containing plasma samples. HI-6 displays the highest reactivation potential whatever the conditions, followed by pralidoxime and the two non quaternary reactivators at the dose of 50 mg/kg bw. But these three last reactivators display equivalent reactivation potential at the same dose of 100 μmol/kg bw. Maximal reactivation potential closely correlates to surviving test results of VX intoxicated mice.

  19. Active sampling technique to enhance chemical signature of buried explosives

    NASA Astrophysics Data System (ADS)

    Lovell, John S.; French, Patrick D.

    2004-09-01

    Deminers and dismounted countermine engineers commonly use metal detectors, ground penetrating radar and probes to locate mines. Many modern landmines have a very low metal content, which severely limits the effectiveness of metal detectors. Canines have also been used for landmine detection for decades. Experiments have shown that canines smell the explosives which are known to leak from most types of landmines. The fact that dogs can detect landmines indicates that vapor sensing is a viable approach to landmine detection. Several groups are currently developing systems to detect landmines by "sniffing" for the ultra-trace explosive vapors above the soil. The amount of material that is available to passive vapor sensing systems is limited to no more than the vapor in equilibrium with the explosive related chemicals (ERCs) distributed in the surface soils over and near the landmine. The low equilibrium vapor pressure of TNT in the soil/atmosphere boundary layer and the limited volume of the boundary layer air imply that passive chemical vapor sensing systems require sensitivities in the picogram range, or lower. ADA is working to overcome many of the limitations of passive sampling methods, by the use of an active sampling method that employs a high-powered (1,200+ joules) strobe lamp to create a highly amplified plume of vapor and/or ERC-bearing fine particulates. Initial investigations have demonstrated that this approach can amplify the detectability of TNT by two or three orders of magnitude. This new active sampling technique could be used with any suitable explosive sensor.

  20. COMPARISON OF MACROINVERTEBRATE SAMPLING METHODS FOR NONWADEABLE STREAMS

    EPA Science Inventory

    The bioassessment of nonwadeable streams in the United States is increasing, but methods for these systems are not as well developed as for wadeable streams. In this study, we compared six benthic macroinvertebrate field sampling methods for nonwadeable streams based on those us...

  1. The Precision Efficacy Analysis for Regression Sample Size Method.

    ERIC Educational Resources Information Center

    Brooks, Gordon P.; Barcikowski, Robert S.

    The general purpose of this study was to examine the efficiency of the Precision Efficacy Analysis for Regression (PEAR) method for choosing appropriate sample sizes in regression studies used for precision. The PEAR method, which is based on the algebraic manipulation of an accepted cross-validity formula, essentially uses an effect size to…

  2. Standard methods for sampling North American freshwater fishes

    USGS Publications Warehouse

    Bonar, Scott A.; Hubert, Wayne A.; Willis, David W.

    2009-01-01

    This important reference book provides standard sampling methods recommended by the American Fisheries Society for assessing and monitoring freshwater fish populations in North America. Methods apply to ponds, reservoirs, natural lakes, and streams and rivers containing cold and warmwater fishes. Range-wide and eco-regional averages for indices of abundance, population structure, and condition for individual species are supplied to facilitate comparisons of standard data among populations. Provides information on converting nonstandard to standard data, statistical and database procedures for analyzing and storing standard data, and methods to prevent transfer of invasive species while sampling.

  3. A multi-dimensional sampling method for locating small scatterers

    NASA Astrophysics Data System (ADS)

    Song, Rencheng; Zhong, Yu; Chen, Xudong

    2012-11-01

    A multiple signal classification (MUSIC)-like multi-dimensional sampling method (MDSM) is introduced to locate small three-dimensional scatterers using electromagnetic waves. The indicator is built with the most stable part of signal subspace of the multi-static response matrix on a set of combinatorial sampling nodes inside the domain of interest. It has two main advantages compared to the conventional MUSIC methods. First, the MDSM is more robust against noise. Second, it can work with a single incidence even for multi-scatterers. Numerical simulations are presented to show the good performance of the proposed method.

  4. Efficiency of snake sampling methods in the Brazilian semiarid region.

    PubMed

    Mesquita, Paula C M D; Passos, Daniel C; Cechin, Sonia Z

    2013-09-01

    The choice of sampling methods is a crucial step in every field survey in herpetology. In countries where time and financial support are limited, the choice of the methods is critical. The methods used to sample snakes often lack objective criteria, and the traditional methods have apparently been more important when making the choice. Consequently researches using not-standardized methods are frequently found in the literature. We have compared four commonly used methods for sampling snake assemblages in a semiarid area in Brazil. We compared the efficacy of each method based on the cost-benefit regarding the number of individuals and species captured, time, and financial investment. We found that pitfall traps were the less effective method in all aspects that were evaluated and it was not complementary to the other methods in terms of abundance of species and assemblage structure. We conclude that methods can only be considered complementary if they are standardized to the objectives of the study. The use of pitfall traps in short-term surveys of the snake fauna in areas with shrubby vegetation and stony soil is not recommended.

  5. Beryllium Wipe Sampling (differing methods - differing exposure potentials)

    SciTech Connect

    Kerr, Kent

    2005-03-09

    This research compared three wipe sampling techniques currently used to test for beryllium contamination on room and equipment surfaces in Department of Energy facilities. Efficiencies of removal of beryllium contamination from typical painted surfaces were tested by wipe sampling without a wetting agent, with water-moistened wipe materials, and by methanol-moistened wipes. Analysis indicated that methanol-moistened wipe sampling removed about twice as much beryllium/oil-film surface contamination as water-moistened wipes, which removed about twice as much residue as dry wipes. Criteria at 10 CFR 850.30 and .31 were established on unspecified wipe sampling method(s). The results of this study reveal a need to identify criteria-setting method and equivalency factors. As facilities change wipe sampling methods among the three compared in this study, these results may be useful for approximate correlations. Accurate decontamination decision-making depends on the selection of appropriate wetting agents for the types of residues and surfaces. Evidence for beryllium sensitization via skin exposure argues in favor of wipe sampling with wetting agents that provide enhanced removal efficiency such as methanol when surface contamination includes oil mist residue.

  6. Sample preparation methods for determination of drugs of abuse in hair samples: A review.

    PubMed

    Vogliardi, Susanna; Tucci, Marianna; Stocchero, Giulia; Ferrara, Santo Davide; Favretto, Donata

    2015-02-01

    Hair analysis has assumed increasing importance in the determination of substances of abuse, both in clinical and forensic toxicology investigations. Hair analysis offers particular advantages over other biological matrices (blood and urine), including a larger window of detection, ease of collection and sample stability. In the present work, an overview of sample preparation techniques for the determination of substances of abuse in hair is provided, specifically regarding the principal steps in hair sample treatment-decontamination, extraction and purification. For this purpose, a survey of publications found in the MEDLINE database from 2000 to date was conducted. The most widely consumed substances of abuse and psychotropic drugs were considered. Trends in simplification of hair sample preparation, washing procedures and cleanup methods are discussed. Alternative sample extraction techniques, such as head-space solid phase microextraction (HS-SPDE), supercritical fluid extraction (SFE) and molecularly imprinted polymers (MIP) are also reported.

  7. SNS Sample Activation Calculator Flux Recommendations and Validation

    SciTech Connect

    McClanahan, Tucker C.; Gallmeier, Franz X.; Iverson, Erik B.; Lu, Wei

    2015-02-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) uses the Sample Activation Calculator (SAC) to calculate the activation of a sample after the sample has been exposed to the neutron beam in one of the SNS beamlines. The SAC webpage takes user inputs (choice of beamline, the mass, composition and area of the sample, irradiation time, decay time, etc.) and calculates the activation for the sample. In recent years, the SAC has been incorporated into the user proposal and sample handling process, and instrument teams and users have noticed discrepancies in the predicted activation of their samples. The Neutronics Analysis Team validated SAC by performing measurements on select beamlines and confirmed the discrepancies seen by the instrument teams and users. The conclusions were that the discrepancies were a result of a combination of faulty neutron flux spectra for the instruments, improper inputs supplied by SAC (1.12), and a mishandling of cross section data in the Sample Activation Program for Easy Use (SAPEU) (1.1.2). This report focuses on the conclusion that the SAPEU (1.1.2) beamline neutron flux spectra have errors and are a significant contributor to the activation discrepancies. The results of the analysis of the SAPEU (1.1.2) flux spectra for all beamlines will be discussed in detail. The recommendations for the implementation of improved neutron flux spectra in SAPEU (1.1.3) are also discussed.

  8. Self-contained cryogenic gas sampling apparatus and method

    DOEpatents

    McManus, G.J.; Motes, B.G.; Bird, S.K.; Kotter, D.K.

    1996-03-26

    Apparatus for obtaining a whole gas sample, is composed of: a sample vessel having an inlet for receiving a gas sample; a controllable valve mounted for controllably opening and closing the inlet; a valve control coupled to the valve for opening and closing the valve at selected times; a portable power source connected for supplying operating power to the valve control; and a cryogenic coolant in thermal communication with the vessel for cooling the interior of the vessel to cryogenic temperatures. A method is described for obtaining an air sample using the apparatus described above, by: placing the apparatus at a location at which the sample is to be obtained; operating the valve control to open the valve at a selected time and close the valve at a selected subsequent time; and between the selected times maintaining the vessel at a cryogenic temperature by heat exchange with the coolant. 3 figs.

  9. Self-contained cryogenic gas sampling apparatus and method

    DOEpatents

    McManus, Gary J.; Motes, Billy G.; Bird, Susan K.; Kotter, Dale K.

    1996-01-01

    Apparatus for obtaining a whole gas sample, composed of: a sample vessel having an inlet for receiving a gas sample; a controllable valve mounted for controllably opening and closing the inlet; a valve control coupled to the valve for opening and closing the valve at selected times; a portable power source connected for supplying operating power to the valve control; and a cryogenic coolant in thermal communication with the vessel for cooling the interior of the vessel to cryogenic temperatures. A method of obtaining an air sample using the apparatus described above, by: placing the apparatus at a location at which the sample is to be obtained; operating the valve control to open the valve at a selected time and close the valve at a selected subsequent time; and between the selected times maintaining the vessel at a cryogenic temperature by heat exchange with the coolant.

  10. Fluidics platform and method for sample preparation and analysis

    SciTech Connect

    Benner, W. Henry; Dzenitis, John M.; Bennet, William J.; Baker, Brian R.

    2014-08-19

    Herein provided are fluidics platform and method for sample preparation and analysis. The fluidics platform is capable of analyzing DNA from blood samples using amplification assays such as polymerase-chain-reaction assays and loop-mediated-isothermal-amplification assays. The fluidics platform can also be used for other types of assays and analyzes. In some embodiments, a sample in a sealed tube can be inserted directly. The following isolation, detection, and analyzes can be performed without a user's intervention. The disclosed platform may also comprises a sample preparation system with a magnetic actuator, a heater, and an air-drying mechanism, and fluid manipulation processes for extraction, washing, elution, assay assembly, assay detection, and cleaning after reactions and between samples.

  11. Examination of Hydrate Formation Methods: Trying to Create Representative Samples

    SciTech Connect

    Kneafsey, T.J.; Rees, E.V.L.; Nakagawa, S.; Kwon, T.-H.

    2011-04-01

    Forming representative gas hydrate-bearing laboratory samples is important so that the properties of these materials may be measured, while controlling the composition and other variables. Natural samples are rare, and have often experienced pressure and temperature changes that may affect the property to be measured [Waite et al., 2008]. Forming methane hydrate samples in the laboratory has been done a number of ways, each having advantages and disadvantages. The ice-to-hydrate method [Stern et al., 1996], contacts melting ice with methane at the appropriate pressure to form hydrate. The hydrate can then be crushed and mixed with mineral grains under controlled conditions, and then compacted to create laboratory samples of methane hydrate in a mineral medium. The hydrate in these samples will be part of the load-bearing frame of the medium. In the excess gas method [Handa and Stupin, 1992], water is distributed throughout a mineral medium (e.g. packed moist sand, drained sand, moistened silica gel, other porous media) and the mixture is brought to hydrate-stable conditions (chilled and pressurized with gas), allowing hydrate to form. This method typically produces grain-cementing hydrate from pendular water in sand [Waite et al., 2004]. In the dissolved gas method [Tohidi et al., 2002], water with sufficient dissolved guest molecules is brought to hydrate-stable conditions where hydrate forms. In the laboratory, this is can be done by pre-dissolving the gas of interest in water and then introducing it to the sample under the appropriate conditions. With this method, it is easier to form hydrate from more soluble gases such as carbon dioxide. It is thought that this method more closely simulates the way most natural gas hydrate has formed. Laboratory implementation, however, is difficult, and sample formation is prohibitively time consuming [Minagawa et al., 2005; Spangenberg and Kulenkampff, 2005]. In another version of this technique, a specified quantity of gas

  12. Characterizing lentic freshwater fish assemblages using multiple sampling methods

    USGS Publications Warehouse

    Fischer, Jesse R.; Quist, Michael

    2014-01-01

    Characterizing fish assemblages in lentic ecosystems is difficult, and multiple sampling methods are almost always necessary to gain reliable estimates of indices such as species richness. However, most research focused on lentic fish sampling methodology has targeted recreationally important species, and little to no information is available regarding the influence of multiple methods and timing (i.e., temporal variation) on characterizing entire fish assemblages. Therefore, six lakes and impoundments (48–1,557 ha surface area) were sampled seasonally with seven gear types to evaluate the combined influence of sampling methods and timing on the number of species and individuals sampled. Probabilities of detection for species indicated strong selectivities and seasonal trends that provide guidance on optimal seasons to use gears when targeting multiple species. The evaluation of species richness and number of individuals sampled using multiple gear combinations demonstrated that appreciable benefits over relatively few gears (e.g., to four) used in optimal seasons were not present. Specifically, over 90 % of the species encountered with all gear types and season combinations (N = 19) from six lakes and reservoirs were sampled with nighttime boat electrofishing in the fall and benthic trawling, modified-fyke, and mini-fyke netting during the summer. Our results indicated that the characterization of lentic fish assemblages was highly influenced by the selection of sampling gears and seasons, but did not appear to be influenced by waterbody type (i.e., natural lake, impoundment). The standardization of data collected with multiple methods and seasons to account for bias is imperative to monitoring of lentic ecosystems and will provide researchers with increased reliability in their interpretations and decisions made using information on lentic fish assemblages.

  13. Compressive sampling in computed tomography: Method and application

    NASA Astrophysics Data System (ADS)

    Hu, Zhanli; Liang, Dong; Xia, Dan; Zheng, Hairong

    2014-06-01

    Since Donoho and Candes et al. published their groundbreaking work on compressive sampling or compressive sensing (CS), CS theory has attracted a lot of attention and become a hot topic, especially in biomedical imaging. Specifically, some CS based methods have been developed to enable accurate reconstruction from sparse data in computed tomography (CT) imaging. In this paper, we will review the progress in CS based CT from aspects of three fundamental requirements of CS: sparse representation, incoherent sampling and reconstruction algorithm. In addition, some potential applications of compressive sampling in CT are introduced.

  14. [Progress in sample preparation and analytical methods for trace polar small molecules in complex samples].

    PubMed

    Zhang, Qianchun; Luo, Xialin; Li, Gongke; Xiao, Xiaohua

    2015-09-01

    Small polar molecules such as nucleosides, amines, amino acids are important analytes in biological, food, environmental, and other fields. It is necessary to develop efficient sample preparation and sensitive analytical methods for rapid analysis of these polar small molecules in complex matrices. Some typical materials in sample preparation, including silica, polymer, carbon, boric acid and so on, are introduced in this paper. Meanwhile, the applications and developments of analytical methods of polar small molecules, such as reversed-phase liquid chromatography, hydrophilic interaction chromatography, etc., are also reviewed.

  15. Comparison of pigment content of paint samples using spectrometric methods.

    PubMed

    Trzcińska, Beata; Kowalski, Rafał; Zięba-Palus, Janina

    2014-09-15

    The aim of the paper was to evaluate the influence of pigment concentration and its distribution in polymer binder on the possibility of colour identification and paint sample comparison. Two sets of paint samples: one containing red and another one green pigment were prepared. Each set consisted of 13 samples differing gradually in the concentration of pigment. To obtain the sets of various colour shades white paint was mixed with the appropriate pigment in the form of a concentrated suspension. After solvents evaporation the samples were examined using spectrometric methods. The resin and main filler were identified by IR method. Colour and white pigments were identified on the base of Raman spectra. Colour of samples were compared based on Vis spectrometry according to colour theory. It was found that samples are homogenous (parameter measuring colour similarity ΔE<3). The values of ΔE between the neighbouring samples in the set revealed decreasing linear function and between the first and following one--a logarithmic function.

  16. A Review of Methods for Detecting Melamine in Food Samples.

    PubMed

    Lu, Yang; Xia, Yinqiang; Liu, Guozhen; Pan, Mingfei; Li, Mengjuan; Lee, Nanju Alice; Wang, Shuo

    2017-01-02

    Melamine is a synthetic chemical used in the manufacture of resins, pigments, and superplasticizers. Human beings can be exposed to melamine through various sources such as migration from related products into foods, pesticide contamination, and illegal addition to foods. Toxicity studies suggest that prolonged consumption of melamine could lead to the formation of kidney stones or even death. Therefore, reliable and accurate detection methods are essential to prevent human exposure to melamine. Sample preparation is of critical importance, since it could directly affect the performance of analytical methods. Some methods for the detection of melamine include instrumental analysis, immunoassays, and sensor methods. In this paper, we have summarized the state-of-the-art methods used for food sample preparation as well as the various detection techniques available for melamine. Combinations of multiple techniques and new materials used in the detection of melamine have also been reviewed. Finally, future perspectives on the applications of microfluidic devices have also been provided.

  17. RAPID METHOD FOR DETERMINATION OF RADIOSTRONTIUM IN EMERGENCY MILK SAMPLES

    SciTech Connect

    Maxwell, S.; Culligan, B.

    2008-07-17

    A new rapid separation method for radiostrontium in emergency milk samples was developed at the Savannah River Site (SRS) Environmental Bioassay Laboratory (Aiken, SC, USA) that will allow rapid separation and measurement of Sr-90 within 8 hours. The new method uses calcium phosphate precipitation, nitric acid dissolution of the precipitate to coagulate residual fat/proteins and a rapid strontium separation using Sr Resin (Eichrom Technologies, Darien, IL, USA) with vacuum-assisted flow rates. The method is much faster than previous method that use calcination or cation exchange pretreatment, has excellent chemical recovery, and effectively removes beta interferences. When a 100 ml sample aliquot is used, the method has a detection limit of 0.5 Bq/L, well below generic emergency action levels.

  18. A comparison of sampling methods for examining the laryngeal microbiome

    PubMed Central

    Hanshew, Alissa S.; Jetté, Marie E.; Tadayon, Stephanie; Thibeault, Susan L.

    2017-01-01

    Shifts in healthy human microbial communities have now been linked to disease in numerous body sites. Noninvasive swabbing remains the sampling technique of choice in most locations; however, it is not well known if this method samples the entire community, or only those members that are easily removed from the surface. We sought to compare the communities found via swabbing and biopsied tissue in true vocal folds, a location that is difficult to sample without causing potential damage and impairment to tissue function. A secondary aim of this study was to determine if swab sampling of the false vocal folds could be used as proxy for true vocal folds. True and false vocal fold mucosal samples (swabbed and biopsied) were collected from six pigs and used for 454 pyrosequencing of the V3–V5 region of the 16S rRNA gene. Most of the alpha and beta measures of diversity were found to be significantly similar between swabbed and biopsied tissue samples. Similarly, the communities found in true and false vocal folds did not differ considerably. These results suggest that samples taken via swabs are sufficient to assess the community, and that samples taken from the false vocal folds may be used as proxies for the true vocal folds. Assessment of these techniques opens an avenue to less traumatic means to explore the role microbes play in the development of diseases of the vocal folds, and perhaps the rest of the respiratory tract. PMID:28362810

  19. NEW COLUMN SEPARATION METHOD FOR EMERGENCY URINE SAMPLES

    SciTech Connect

    Maxwell, S; Brian Culligan, B

    2007-08-28

    The Savannah River Site Environmental Bioassay Lab participated in the 2007 NRIP Emergency Response program administered by the National Institute for Standards and Technology (NIST) in May, 2007. A new rapid column separation method was applied directly to the NRIP 2007 emergency urine samples, with only minimal sample preparation to reduce preparation time. Calcium phosphate precipitation, previously used to pre-concentrate actinides and Sr-90 in NRIP 2006 urine and water samples, was not used for the NRIP 2007 urine samples. Instead, the raw urine was acidified and passed directly through the stacked resin columns (TEVA+TRU+SR Resins) to separate the actinides and strontium from the NRIP urine samples more quickly. This improvement reduced sample preparation time for the NRIP 2007 emergency urine analyses significantly. This approach works well for small volume urine samples expected during an emergency response event. Based on initial feedback from NIST, the SRS Environmental Bioassay Lab had the most rapid analysis times for actinides and strontium-90 analyses for NRIP 2007 urine samples.

  20. On the Exploitation of Sensitivity Derivatives for Improving Sampling Methods

    NASA Technical Reports Server (NTRS)

    Cao, Yanzhao; Hussaini, M. Yousuff; Zang, Thomas A.

    2003-01-01

    Many application codes, such as finite-element structural analyses and computational fluid dynamics codes, are capable of producing many sensitivity derivatives at a small fraction of the cost of the underlying analysis. This paper describes a simple variance reduction method that exploits such inexpensive sensitivity derivatives to increase the accuracy of sampling methods. Three examples, including a finite-element structural analysis of an aircraft wing, are provided that illustrate an order of magnitude improvement in accuracy for both Monte Carlo and stratified sampling schemes.

  1. Two-dimensional signal reconstruction: The correlation sampling method

    SciTech Connect

    Roman, H. E.

    2007-12-15

    An accurate approach for reconstructing a time-dependent two-dimensional signal from non-synchronized time series recorded at points located on a grid is discussed. The method, denoted as correlation sampling, improves the standard conditional sampling approach commonly employed in the study of turbulence in magnetoplasma devices. Its implementation is illustrated in the case of an artificial time-dependent signal constructed using a fractal algorithm that simulates a fluctuating surface. A statistical method is also discussed for distinguishing coherent (i.e., collective) from purely random (noisy) behavior for such two-dimensional fluctuating phenomena.

  2. Evaluation of Stress Loaded Steel Samples Using Selected Electromagnetic Methods

    SciTech Connect

    Chady, T.

    2004-02-26

    In this paper the magnetic leakage flux and eddy current method were used to evaluate changes of materials' properties caused by stress. Seven samples made of ferromagnetic material with different level of applied stress were prepared. First, the leakage magnetic fields were measured by scanning the surface of the specimens with GMR gradiometer. Next, the same samples were evaluated using an eddy current sensor. A comparison between results obtained from both methods was carried out. Finally, selected parameters of the measured signal were calculated and utilized to evaluate level of the applied stress. A strong coincidence between amount of the applied stress and the maximum amplitude of the derivative was confirmed.

  3. A method for time-resolved calorespirometry of terrestrial samples.

    PubMed

    Wadsö, Lars

    2015-04-01

    A new vessel for simultaneous isothermal calorimetry and respirometry (calorespirometry) on terrestrial (non-aqueous) samples has been developed. All types of small (<1 g) biological samples (insects, soil, leaves, fungi, etc.) can be studied. The respirometric measurements are made by opening and closing a valve to a vial inside the sample ampoule containing a carbon dioxide absorbent. Typically a 7 h measurement results in seven measurements of heat production rate, oxygen consumption and carbon dioxide production, which can be used to evaluate how the metabolic activity in a sample changes over time. Results from three experiments on leaves, a cut vegetable, and mold are given. As uncertainties--especially in the carbon dioxide production--tend to be quite high, improvements to the technique are also discussed.

  4. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-01

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  5. A molecular method to assess Phytophthora diversity in environmental samples.

    PubMed

    Scibetta, Silvia; Schena, Leonardo; Chimento, Antonio; Cacciola, Santa O; Cooke, David E L

    2012-03-01

    Current molecular detection methods for the genus Phytophthora are specific to a few key species rather than the whole genus and this is a recognized weakness of protocols for ecological studies and international plant health legislation. In the present study a molecular approach was developed to detect Phytophthora species in soil and water samples using novel sets of genus-specific primers designed against the internal transcribed spacer (ITS) regions. Two different rDNA primer sets were tested: one assay amplified a long product including the ITS1, 5.8S and ITS2 regions (LP) and the other a shorter product including the ITS1 only (SP). Both assays specifically amplified products from Phytophthora species without cross-reaction with the related Pythium s. lato, however the SP assay proved the more sensitive and reliable. The method was validated using woodland soil and stream water from Invergowrie, Scotland. On-site use of a knapsack sprayer and in-line water filters proved more rapid and effective than centrifugation at sampling Phytophthora propagules. A total of 15 different Phytophthora phylotypes were identified which clustered within the reported ITS-clades 1, 2, 3, 6, 7 and 8. The range and type of the sequences detected varied from sample to sample and up to three and five different Phytophthora phylotypes were detected within a single sample of soil or water, respectively. The most frequently detected sequences were related to members of ITS-clade 6 (i.e. P. gonapodyides-like). The new method proved very effective at discriminating multiple species in a given sample and can also detect as yet unknown species. The reported primers and methods will prove valuable for ecological studies, biosecurity and commercial plant, soil or water (e.g. irrigation water) testing as well as the wider metagenomic sampling of this fascinating component of microbial pathogen diversity.

  6. RAPID SEPARATION METHOD FOR EMERGENCY WATER AND URINE SAMPLES

    SciTech Connect

    Maxwell, S.; Culligan, B.

    2008-08-27

    The Savannah River Site Environmental Bioassay Lab participated in the 2008 NRIP Emergency Response program administered by the National Institute for Standards and Technology (NIST) in May, 2008. A new rapid column separation method was used for analysis of actinides and {sup 90}Sr the NRIP 2008 emergency water and urine samples. Significant method improvements were applied to reduce analytical times. As a result, much faster analysis times were achieved, less than 3 hours for determination of {sup 90}Sr and 3-4 hours for actinides. This represents a 25%-33% improvement in analysis times from NRIP 2007 and a {approx}100% improvement compared to NRIP 2006 report times. Column flow rates were increased by a factor of two, with no significant adverse impact on the method performance. Larger sample aliquots, shorter count times, faster cerium fluoride microprecipitation and streamlined calcium phosphate precipitation were also employed. Based on initial feedback from NIST, the SRS Environmental Bioassay Lab had the most rapid analysis times for actinides and {sup 90}Sr analyses for NRIP 2008 emergency urine samples. High levels of potential matrix interferences may be present in emergency samples and rugged methods are essential. Extremely high levels of {sup 210}Po were found to have an adverse effect on the uranium results for the NRIP-08 urine samples, while uranium results for NRIP-08 water samples were not affected. This problem, which was not observed for NRIP-06 or NRIP-07 urine samples, was resolved by using an enhanced {sup 210}Po removal step, which will be described.

  7. Proteome Analysis of Human Perilymph using an Intraoperative Sampling Method.

    PubMed

    Schmitt, Heike Andrea; Pich, Andreas; Schröder, Anke; Scheper, Verena; Lilli, Giorgio; Reuter, Günter; Lenarz, Thomas

    2017-03-10

    The knowledge about the etiology and pathophysiology of sensorineural hearing loss (SNHL) is still very limited. The project aims at the improvement of understanding different types of SNHL by proteome analysis of human perilymph. Sampling of perilymph has been established during inner ear surgeries (cochlear implant and vestibular schwannoma surgeries) and safety of the sampling method was determined by pure tone audiometry. An in-depth shot-gun proteomics approach was performed to identify cochlear proteins and individual proteome in perilymph of patients. This method enables the identification and quantification of protein composition of perilymph. The proteome of 41 collected perilymph samples with volumes of 1-12 µl was analyzed by data dependent acquisition resulting in overall 878 detected protein groups. At least 203 protein groups were solely identified in perilymph, not in reference samples (serum, cerebrospinal fluid), displaying a specific protein pattern for perilymph. Samples were grouped according to age of patients and type of surgery leading to identification of some proteins specific to particular subgroups. Proteins with different abundances between different sample groups were subjected to classification by gene ontology annotations. The identified proteins might be used to develop tools for non-invasive inner ear diagnostics and to elucidate molecular profiles of SNHL.

  8. Detection of autoinducer (AI-2)-like activity in food samples.

    PubMed

    Sivakumar, Kirthiram K; Jesudhasan, Palmy R; Pillai, Suresh D

    2011-01-01

    The contamination, survival, and possible foodborne disease outbreaks are major issues confronting the food industry. However, from a microbial perspective, any food whether natural or processed is just another environmental niche that is available for colonization. Quorum sensing or cell-cell communication is a process by which microorganisms are thought to communicate with each other using a variety of small molecules termed autoinducers. The autoinducer AI-2 is thought to be a universal signaling molecule due to its ability to modulate the gene expression of a number of different bacterial species and genera. Pathogens such as Pseudomonas aeruginosa, Aeromonas hydrophila, Vibrio anguillarum, Streptococcus sp., and Burkholderia cepacia form biofilms on a variety of man-made and natural surfaces using cell-cell mechanisms. It is important to detect and study autoinducers and their activities in foods, since a better understanding of these molecules in food and food ingredients may help in designing new approaches to thwart microbial persistence and biofilm formation. The autoinducer AI-2 is thought to be involved in microbial attachment and biofilm formation leading to food spoilage. To better understand microbial cell-cell signaling in foods especially as it relates to pathogen persistence, biofilm formation, and food spoilage, methods to process, extract, and purify autoinducer molecules need to be developed. This chapter details methods to process food samples to obtain cell-free supernatants (CFS), which could subsequently be tested for the presence of AI-2 or "AI-2-like activity" in the extracted CFS using autoinducer bioassays. Additionally, the method of synthesizing AI-2 in the laboratory is also provided. The methods that are presented in this chapter are based on previously published research articles from the authors' laboratory.

  9. Development of an automated data processing method for sample to sample comparison of seized methamphetamines.

    PubMed

    Choe, Sanggil; Lee, Jaesin; Choi, Hyeyoung; Park, Yujin; Lee, Heesang; Pyo, Jaesung; Jo, Jiyeong; Park, Yonghoon; Choi, Hwakyung; Kim, Suncheun

    2012-11-30

    The information about the sources of supply, trafficking routes, distribution patterns and conspiracy links can be obtained from methamphetamine profiling. The precursor and synthetic method for the clandestine manufacture can be estimated from the analysis of minor impurities contained in methamphetamine. Also, the similarity between samples can be evaluated using the peaks that appear in chromatograms. In South Korea, methamphetamine was the most popular drug but the total seized amount of methamphetamine whole through the country was very small. Therefore, it would be more important to find the links between samples than the other uses of methamphetamine profiling. Many Asian countries including Japan and South Korea have been using the method developed by National Research Institute of Police Science of Japan. The method used gas chromatography-flame ionization detector (GC-FID), DB-5 column and four internal standards. It was developed to increase the amount of impurities and minimize the amount of methamphetamine. After GC-FID analysis, the raw data have to be processed. The data processing steps are very complex and require a lot of time and effort. In this study, Microsoft Visual Basic Application (VBA) modules were developed to handle these data processing steps. This module collected the results from the data into an Excel file and then corrected the retention time shift and response deviation generated from the sample preparation and instruments analysis. The developed modules were tested for their performance using 10 samples from 5 different cases. The processed results were analyzed with Pearson correlation coefficient for similarity assessment and the correlation coefficient of the two samples from the same case was more than 0.99. When the modules were applied to 131 seized methamphetamine samples, four samples from two different cases were found to have the common origin and the chromatograms of the four samples were appeared visually identical

  10. METHODS FOR THE ANALYSIS OF CARPET SAMPLES FOR ASBESTOS

    EPA Science Inventory

    Assessing asbestos fiber contamination in a carpet is complicated by the nature of the carpeting – because of the pile’s rough surface and thickness, samples cannot be collected directly from carpet for analysis by TEM. Two indirect methods are currently used by laboratories when...

  11. A General Linear Method for Equating with Small Samples

    ERIC Educational Resources Information Center

    Albano, Anthony D.

    2015-01-01

    Research on equating with small samples has shown that methods with stronger assumptions and fewer statistical estimates can lead to decreased error in the estimated equating function. This article introduces a new approach to linear observed-score equating, one which provides flexible control over how form difficulty is assumed versus estimated…

  12. 40 CFR Appendix I to Part 261 - Representative Sampling Methods

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Representative Sampling Methods I Appendix I to Part 261 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) IDENTIFICATION AND LISTING OF HAZARDOUS WASTE Pt. 261, App. I Appendix I to Part...

  13. 40 CFR Appendix I to Part 261 - Representative Sampling Methods

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Representative Sampling Methods I Appendix I to Part 261 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) IDENTIFICATION AND LISTING OF HAZARDOUS WASTE Pt. 261, App. I Appendix I to Part...

  14. 40 CFR Appendix I to Part 261 - Representative Sampling Methods

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Representative Sampling Methods I Appendix I to Part 261 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) IDENTIFICATION AND LISTING OF HAZARDOUS WASTE Pt. 261, App. I Appendix I to Part...

  15. 40 CFR Appendix I to Part 261 - Representative Sampling Methods

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Representative Sampling Methods I Appendix I to Part 261 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) IDENTIFICATION AND LISTING OF HAZARDOUS WASTE Pt. 261, App. I Appendix I to Part...

  16. A DOE manual: DOE methods for evaluating environmental and waste management samples

    SciTech Connect

    Goheen, S.C.; Fadeff, S.K.; Sklarew, D.S.; McCulloch, M.; Mong, G.M.; Riley, R.G.; Thomas, B.L.

    1994-08-01

    DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) is a guidance/methods document supporting environmental restoration (ER) and waste management (WM) (collectively referred to as EM) sampling and analysis activities at US Department of Energy (DOE) sites. DOE Methods is intended to supplement existing guidance documents (e.g., the US Environmental Protection Agency`s Test Methods for Evaluating Solid Waste, SW-846), which apply to low-level or non-radioactive samples, and the complexities of waste and environmental samples encountered at DOE sites. The document contains quality assurance (QA), quality control (QC), safety, sampling, organic analysis, inorganic analysis, and radio-analytical guidance as well as sampling and analytical methods. It is updated every six months (April and October) with additional methods. As of April 1994, DOE methods contained 3 sampling and 39 analytical methods. It is anticipated that between 10 and 20 new methods will be added in October 1994. All methods are either peer reviewed and contain performance data, or are included as draft methods.

  17. Extravehicular Activity Asteroid Exploration and Sample Collection Capability

    NASA Technical Reports Server (NTRS)

    Sipila, Stephanie A.; Scoville, Zebulon C.; Bowie, Jonathan T.; Buffington, Jesse A.

    2014-01-01

    One of the challenging primary objectives associated with NASA's Asteroid Redirect Crewed Mission (ARCM) is to demonstrate deep space Extravehicular Activity (EVA) and tools and to obtain asteroid samples to return to Earth for further study. Prior Shuttle and International Space Station (ISS) spacewalks have benefited from engineered EVA interfaces which have been designed and manufactured on Earth. Rigid structurally mounted handrails, and tools with customized interfaces and restraints optimize EVA performance. For ARCM, EVA complexity increases due to the uncertainty of the asteroid properties. The variability of rock size, shape and composition, as well as behavior of the asteroid capture mechanism will complicate EVA translation, tool restraint, and body stabilization. The unknown asteroid hardness and brittleness will complicate tool use. The rock surface will introduce added safety concerns for cut gloves and debris control. Feasible solutions to meet ARCM EVA objectives were identified using experience gained during Apollo, Shuttle, and ISS EVAs, terrestrial mountaineering practices, NASA Extreme Environment Mission Operations (NEEMO) 16 mission, and during Neutral Buoyancy Laboratory testing in the Modified Advanced Crew Escape Suit (MACES) suit. This paper will summarize the overall operational concepts for conducting EVAs for the ARCM mission including translation paths and body restraint methods, potential tools used to extract the samples, design implications for the Asteroid Redirect Vehicle (ARV) for EVA, and the results of early development testing of potential EVA tasks.

  18. Comparison of DNA preservation methods for environmental bacterial community samples

    USGS Publications Warehouse

    Gray, Michael A.; Pratte, Zoe A.; Kellogg, Christina A.

    2013-01-01

    Field collections of environmental samples, for example corals, for molecular microbial analyses present distinct challenges. The lack of laboratory facilities in remote locations is common, and preservation of microbial community DNA for later study is critical. A particular challenge is keeping samples frozen in transit. Five nucleic acid preservation methods that do not require cold storage were compared for effectiveness over time and ease of use. Mixed microbial communities of known composition were created and preserved by DNAgard™, RNAlater®, DMSO–EDTA–salt (DESS), FTA® cards, and FTA Elute® cards. Automated ribosomal intergenic spacer analysis and clone libraries were used to detect specific changes in the faux communities over weeks and months of storage. A previously known bias in FTA® cards that results in lower recovery of pure cultures of Gram-positive bacteria was also detected in mixed community samples. There appears to be a uniform bias across all five preservation methods against microorganisms with high G + C DNA. Overall, the liquid-based preservatives (DNAgard™, RNAlater®, and DESS) outperformed the card-based methods. No single liquid method clearly outperformed the others, leaving method choice to be based on experimental design, field facilities, shipping constraints, and allowable cost.

  19. Comparison of aquatic macroinvertebrate samples collected using different field methods

    USGS Publications Warehouse

    Lenz, Bernard N.; Miller, Michael A.

    1996-01-01

    Government agencies, academic institutions, and volunteer monitoring groups in the State of Wisconsin collect aquatic macroinvertebrate data to assess water quality. Sampling methods differ among agencies, reflecting the differences in the sampling objectives of each agency. Lack of infor- mation about data comparability impedes data shar- ing among agencies, which can result in duplicated sampling efforts or the underutilization of avail- able information. To address these concerns, com- parisons were made of macroinvertebrate samples collected from wadeable streams in Wisconsin by personnel from the U.S. Geological Survey- National Water Quality Assessment Program (USGS-NAWQA), the Wisconsin Department of Natural Resources (WDNR), the U.S. Department of Agriculture-Forest Service (USDA-FS), and volunteers from the Water Action Volunteer-Water Quality Monitoring Program (WAV). This project was part of the Intergovernmental Task Force on Monitoring Water Quality (ITFM) Wisconsin Water Resources Coordination Project. The numbers, types, and environmental tolerances of the organ- isms collected were analyzed to determine if the four different field methods that were used by the different agencies and volunteer groups provide comparable results. Additionally, this study com- pared the results of samples taken from different locations and habitats within the same streams.

  20. Sample Selected Averaging Method for Analyzing the Event Related Potential

    NASA Astrophysics Data System (ADS)

    Taguchi, Akira; Ono, Youhei; Kimura, Tomoaki

    The event related potential (ERP) is often measured through the oddball task. On the oddball task, subjects are given “rare stimulus” and “frequent stimulus”. Measured ERPs were analyzed by the averaging technique. In the results, amplitude of the ERP P300 becomes large when the “rare stimulus” is given. However, measured ERPs are included samples without an original feature of ERP. Thus, it is necessary to reject unsuitable measured ERPs when using the averaging technique. In this paper, we propose the rejection method for unsuitable measured ERPs for the averaging technique. Moreover, we combine the proposed method and Woody's adaptive filter method.

  1. A flexible importance sampling method for integrating subgrid processes

    DOE PAGES

    Raut, E. K.; Larson, V. E.

    2016-01-29

    Numerical models of weather and climate need to compute grid-box-averaged rates of physical processes such as microphysics. These averages are computed by integrating subgrid variability over a grid box. For this reason, an important aspect of atmospheric modeling is spatial integration over subgrid scales. The needed integrals can be estimated by Monte Carlo integration. Monte Carlo integration is simple and general but requires many evaluations of the physical process rate. To reduce the number of function evaluations, this paper describes a new, flexible method of importance sampling. It divides the domain of integration into eight categories, such as the portion that containsmore » both precipitation and cloud, or the portion that contains precipitation but no cloud. It then allows the modeler to prescribe the density of sample points within each of the eight categories. The new method is incorporated into the Subgrid Importance Latin Hypercube Sampler (SILHS). The resulting method is tested on drizzling cumulus and stratocumulus cases. In the cumulus case, the sampling error can be considerably reduced by drawing more sample points from the region of rain evaporation.« less

  2. A flexible importance sampling method for integrating subgrid processes

    NASA Astrophysics Data System (ADS)

    Raut, E. K.; Larson, V. E.

    2016-01-01

    Numerical models of weather and climate need to compute grid-box-averaged rates of physical processes such as microphysics. These averages are computed by integrating subgrid variability over a grid box. For this reason, an important aspect of atmospheric modeling is spatial integration over subgrid scales. The needed integrals can be estimated by Monte Carlo integration. Monte Carlo integration is simple and general but requires many evaluations of the physical process rate. To reduce the number of function evaluations, this paper describes a new, flexible method of importance sampling. It divides the domain of integration into eight categories, such as the portion that contains both precipitation and cloud, or the portion that contains precipitation but no cloud. It then allows the modeler to prescribe the density of sample points within each of the eight categories. The new method is incorporated into the Subgrid Importance Latin Hypercube Sampler (SILHS). The resulting method is tested on drizzling cumulus and stratocumulus cases. In the cumulus case, the sampling error can be considerably reduced by drawing more sample points from the region of rain evaporation.

  3. New Methods of Sample Preparation for Atom Probe Specimens

    NASA Technical Reports Server (NTRS)

    Kuhlman, Kimberly, R.; Kowalczyk, Robert S.; Ward, Jennifer R.; Wishard, James L.; Martens, Richard L.; Kelly, Thomas F.

    2003-01-01

    Magnetite is a common conductive mineral found on Earth and Mars. Disk-shaped precipitates approximately 40 nm in diameter have been shown to have manganese and aluminum concentrations. Atom-probe field-ion microscopy (APFIM) is the only technique that can potentially quantify the composition of these precipitates. APFIM will be used to characterize geological and planetary materials, analyze samples of interest for geomicrobiology; and, for the metrology of nanoscale instrumentation. Prior to APFIM sample preparation was conducted by electropolishing, the method of sharp shards (MSS), or Bosch process (deep reactive ion etching) with focused ion beam (FIB) milling as a final step. However, new methods are required for difficult samples. Many materials are not easily fabricated using electropolishing, MSS, or the Bosch process, FIB milling is slow and expensive, and wet chemistry and the reactive ion etching are typically limited to Si and other semiconductors. APFIM sample preparation using the dicing saw is commonly used to section semiconductor wafers into individual devices following manufacture. The dicing saw is a time-effective method for preparing high aspect ratio posts of poorly conducting materials. Femtosecond laser micromachining is also suitable for preparation of posts. FIB time required is reduced by about a factor of 10 and multi-tip specimens can easily be fabricated using the dicing saw.

  4. Extravehicular Activity Asteroid Exploration and Sample Collection Capability

    NASA Technical Reports Server (NTRS)

    Scoville, Zebulon; Sipila, Stephanie; Bowie, Jonathan

    2014-01-01

    NASA's Asteroid Redirect Crewed Mission (ARCM) is challenged with primary mission objectives of demonstrating deep space Extravehicular Activity (EVA) and tools, and obtaining asteroid samples to return to Earth for further study. Although the Modified Advanced Crew Escape Suit (MACES) is used for the EVAs, it has limited mobility which increases fatigue and decreases the crews' capability to perform EVA tasks. Furthermore, previous Shuttle and International Space Station (ISS) spacewalks have benefited from EVA interfaces which have been designed and manufactured on Earth. Rigid structurally mounted handrails, and tools with customized interfaces and restraints optimize EVA performance. For ARCM, some vehicle interfaces and tools can leverage heritage designs and experience. However, when the crew ventures onto an asteroid capture bag to explore the asteroid and collect rock samples, EVA complexity increases due to the uncertainty of the asteroid properties. The variability of rock size, shape and composition, as well as bunching of the fabric bag will complicate EVA translation, tool restraint and body stabilization. The unknown asteroid hardness and brittleness will complicate tool use. The rock surface will introduce added safety concerns for cut gloves and debris control. Feasible solutions to meet ARCM EVA objectives were identified using experience gained during Apollo, Shuttle, and ISS EVAs, terrestrial mountaineering practices, NASA Extreme Environment Mission Operations (NEEMO) 16 mission, and during Neutral Buoyancy Laboratory testing in the MACES suit. The proposed concept utilizes expandable booms and integrated features of the asteroid capture bag to position and restrain the crew at the asteroid worksite. These methods enable the capability to perform both finesse, and high load tasks necessary to collect samples for scientific characterization of the asteroid. This paper will explore the design trade space and options that were examined for EVA, the

  5. Transuranic waste characterization sampling and analysis methods manual. Revision 1

    SciTech Connect

    Suermann, J.F.

    1996-04-01

    This Methods Manual provides a unified source of information on the sampling and analytical techniques that enable Department of Energy (DOE) facilities to comply with the requirements established in the current revision of the Transuranic Waste Characterization Quality Assurance Program Plan (QAPP) for the Waste Isolation Pilot Plant (WIPP) Transuranic (TRU) Waste Characterization Program (the Program) and the WIPP Waste Analysis Plan. This Methods Manual includes all of the testing, sampling, and analytical methodologies accepted by DOE for use in implementing the Program requirements specified in the QAPP and the WIPP Waste Analysis Plan. The procedures in this Methods Manual are comprehensive and detailed and are designed to provide the necessary guidance for the preparation of site-specific procedures. With some analytical methods, such as Gas Chromatography/Mass Spectrometry, the Methods Manual procedures may be used directly. With other methods, such as nondestructive characterization, the Methods Manual provides guidance rather than a step-by-step procedure. Sites must meet all of the specified quality control requirements of the applicable procedure. Each DOE site must document the details of the procedures it will use and demonstrate the efficacy of such procedures to the Manager, National TRU Program Waste Characterization, during Waste Characterization and Certification audits.

  6. RAPID SEPARATION METHOD FOR ACTINIDES IN EMERGENCY SOIL SAMPLES

    SciTech Connect

    Maxwell, S.; Culligan, B.; Noyes, G.

    2009-11-09

    A new rapid method for the determination of actinides in soil and sediment samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for samples up to 2 grams in emergency response situations. The actinides in soil method utilizes a rapid sodium hydroxide fusion method, a lanthanum fluoride soil matrix removal step, and a streamlined column separation process with stacked TEVA, TRU and DGA Resin cartridges. Lanthanum was separated rapidly and effectively from Am and Cm on DGA Resin. Vacuum box technology and rapid flow rates are used to reduce analytical time. Alpha sources are prepared using cerium fluoride microprecipitation for counting by alpha spectrometry. The method showed high chemical recoveries and effective removal of interferences. This new procedure was applied to emergency soil samples received in the NRIP Emergency Response exercise administered by the National Institute for Standards and Technology (NIST) in April, 2009. The actinides in soil results were reported within 4-5 hours with excellent quality.

  7. Spanish Multicenter Normative Studies (NEURONORMA Project): methods and sample characteristics.

    PubMed

    Peña-Casanova, Jordi; Blesa, Rafael; Aguilar, Miquel; Gramunt-Fombuena, Nina; Gómez-Ansón, Beatriz; Oliva, Rafael; Molinuevo, José Luis; Robles, Alfredo; Barquero, María Sagrario; Antúnez, Carmen; Martínez-Parra, Carlos; Frank-García, Anna; Fernández, Manuel; Alfonso, Verónica; Sol, Josep M

    2009-06-01

    This paper describes the methods and sample characteristics of a series of Spanish normative studies (The NEURONORMA project). The primary objective of our research was to collect normative and psychometric information on a sample of people aged over 49 years. The normative information was based on a series of selected, but commonly used, neuropsychological tests covering attention, language, visuo-perceptual abilities, constructional tasks, memory, and executive functions. A sample of 356 community dwelling individuals was studied. Demographics, socio-cultural, and medical data were collected. Cognitive normality was validated via informants and a cognitive screening test. Norms were calculated for midpoint age groups. Effects of age, education, and sex were determined. The use of these norms should improve neuropsychological diagnostic accuracy in older Spanish subjects. These data may also be of considerable use for comparisons with other normative studies. Limitations of these normative data are also commented on.

  8. A direct method for e-cigarette aerosol sample collection.

    PubMed

    Olmedo, Pablo; Navas-Acien, Ana; Hess, Catherine; Jarmul, Stephanie; Rule, Ana

    2016-08-01

    E-cigarette use is increasing in populations around the world. Recent evidence has shown that the aerosol produced by e-cigarettes can contain a variety of toxicants. Published studies characterizing toxicants in e-cigarette aerosol have relied on filters, impingers or sorbent tubes, which are methods that require diluting or extracting the sample in a solution during collection. We have developed a collection system that directly condenses e-cigarette aerosol samples for chemical and toxicological analyses. The collection system consists of several cut pipette tips connected with short pieces of tubing. The pipette tip-based collection system can be connected to a peristaltic pump, a vacuum pump, or directly to an e-cigarette user for the e-cigarette aerosol to flow through the system. The pipette tip-based system condenses the aerosol produced by the e-cigarette and collects a liquid sample that is ready for analysis without the need of intermediate extraction solutions. We tested a total of 20 e-cigarettes from 5 different brands commercially available in Maryland. The pipette tip-based collection system condensed between 0.23 and 0.53mL of post-vaped e-liquid after 150 puffs. The proposed method is highly adaptable, can be used during field work and in experimental settings, and allows collecting aerosol samples from a wide variety of e-cigarette devices, yielding a condensate of the likely exact substance that is being delivered to the lungs.

  9. A Mixed Methods Investigation of Mixed Methods Sampling Designs in Social and Health Science Research

    ERIC Educational Resources Information Center

    Collins, Kathleen M. T.; Onwuegbuzie, Anthony J.; Jiao, Qun G.

    2007-01-01

    A sequential design utilizing identical samples was used to classify mixed methods studies via a two-dimensional model, wherein sampling designs were grouped according to the time orientation of each study's components and the relationship of the qualitative and quantitative samples. A quantitative analysis of 121 studies representing nine fields…

  10. Rock sampling. [method for controlling particle size distribution

    NASA Technical Reports Server (NTRS)

    Blum, P. (Inventor)

    1971-01-01

    A method for sampling rock and other brittle materials and for controlling resultant particle sizes is described. The method involves cutting grooves in the rock surface to provide a grouping of parallel ridges and subsequently machining the ridges to provide a powder specimen. The machining step may comprise milling, drilling, lathe cutting or the like; but a planing step is advantageous. Control of the particle size distribution is effected primarily by changing the height and width of these ridges. This control exceeds that obtainable by conventional grinding.

  11. Recent advances in sample preparation techniques for effective bioanalytical methods.

    PubMed

    Kole, Prashant Laxman; Venkatesh, Gantala; Kotecha, Jignesh; Sheshala, Ravi

    2011-01-01

    This paper reviews the recent developments in bioanalysis sample preparation techniques and gives an update on basic principles, theory, applications and possibilities for automation, and a comparative discussion on the advantages and limitation of each technique. Conventional liquid-liquid extraction (LLE), protein precipitation (PP) and solid-phase extraction (SPE) techniques are now been considered as methods of the past. The last decade has witnessed a rapid development of novel sample preparation techniques in bioanalysis. Developments in SPE techniques such as selective sorbents and in the overall approach to SPE, such as hybrid SPE and molecularly imprinted polymer SPE, have been addressed. Considerable literature has been published in the area of solid-phase micro-extraction and its different versions, e.g. stir bar sorptive extraction, and their application in the development of selective and sensitive bioanalytical methods. Techniques such as dispersive solid-phase extraction, disposable pipette extraction and micro-extraction by packed sorbent offer a variety of extraction phases and provide unique advantages to bioanalytical methods. On-line SPE utilizing column-switching techniques is rapidly gaining acceptance in bioanalytical applications. PP sample preparation techniques such as PP filter plates/tubes offer many advantages like removal of phospholipids and proteins in plasma/serum. Newer approaches to conventional LLE techniques (salting-out LLE) are also covered in this review article.

  12. Activation energy for a model ferrous-ferric half reaction from transition path sampling.

    PubMed

    Drechsel-Grau, Christof; Sprik, Michiel

    2012-01-21

    Activation parameters for the model oxidation half reaction of the classical aqueous ferrous ion are compared for different molecular simulation techniques. In particular, activation free energies are obtained from umbrella integration and Marcus theory based thermodynamic integration, which rely on the diabatic gap as the reaction coordinate. The latter method also assumes linear response, and both methods obtain the activation entropy and the activation energy from the temperature dependence of the activation free energy. In contrast, transition path sampling does not require knowledge of the reaction coordinate and directly yields the activation energy [C. Dellago and P. G. Bolhuis, Mol. Simul. 30, 795 (2004)]. Benchmark activation energies from transition path sampling agree within statistical uncertainty with activation energies obtained from standard techniques requiring knowledge of the reaction coordinate. In addition, it is found that the activation energy for this model system is significantly smaller than the activation free energy for the Marcus model, approximately half the value, implying an equally large entropy contribution.

  13. Minimum detectable activity concentration in direct alpha spectrometry from outdoor air samples: continuous monitoring versus separate sampling and counting.

    PubMed

    Pöllänen, R; Siiskonen, T

    2006-02-01

    Rapid method for identifying the presence of alpha particle emitting radionuclides in outdoor air is of paramount importance should a nuclear or radiological incident occur. Minimum detectable activity concentrations of U, U, Pu, and Pu in outdoor air are calculated for two direct alpha spectrometry methods: continuous air monitoring is compared with separate sampling and subsequent alpha particle counting in a vacuum chamber. The radon progeny activity concentration typical for outdoor air and the effects for the alpha particle spectra caused by the properties of the filter and the aerosol particles are taken into account using measurements and Monte Carlo simulations. Continuous air monitoring is a faster method for identifying the presence of (trans)uranium elements when their activity concentration is considerably higher than the typical detection limit. Separate sampling and counting in a vacuum chamber is a more sensitive method when concentrations are close to the detection limit and when the duration of the sampling-counting cycle is greater than approximately 2 h. The method may serve as a tool for rapid field measurements.

  14. Sediment sampling and processing methods in Hungary, and possible improvements

    NASA Astrophysics Data System (ADS)

    Tamas, Eniko Anna; Koch, Daniel; Varga, Gyorgy

    2016-04-01

    The importance of the monitoring of sediment processes is unquestionable: sediment balance of regulated rivers suffered substantial alterations in the past century, affecting navigation, energy production, fish habitats and floodplain ecosystems alike; infiltration times to our drinking water wells have shortened, exposing them to an eventual pollution event and making them vulnerable; and sediment-attached contaminants accumulate in floodplains and reservoirs, threatening our healthy environment. The changes in flood characteristics and rating curves of our rivers are regularly being researched and described, involving state-of-the-art measurement methods, modeling tools and traditional statistics. Sediment processes however, are much less known. Unlike the investigation of flow processes, sediment-related research is scarce, which is partly due to the outdated methodology and poor database background in the specific field. Sediment-related data, information and analyses form an important and integral part of Civil engineering in relation to rivers all over the world. In relation to the second largest river of Europe, the Danube, it is widely known in expert community and for long discussed at different expert forums that the sediment balance of the river Danube has changed drastically over the past century. Sediment monitoring on the river Danube started as early as the end of the 19th century, with scattered measurements carried out. Regular sediment sampling was developed in the first half of the 20th century all along the river, with different station density and monitoring frequencies in different countries. After the first few decades of regular sampling, the concept of (mainly industrial) development changed along the river and data needs changed as well, furthermore the complicated and inexact methods of sampling bed load on the alluvial reach of the river were not developed further. Frequency of suspended sediment sampling is very low along the river

  15. Cool walking: a new Markov chain Monte Carlo sampling method.

    PubMed

    Brown, Scott; Head-Gordon, Teresa

    2003-01-15

    Effective relaxation processes for difficult systems like proteins or spin glasses require special simulation techniques that permit barrier crossing to ensure ergodic sampling. Numerous adaptations of the venerable Metropolis Monte Carlo (MMC) algorithm have been proposed to improve its sampling efficiency, including various hybrid Monte Carlo (HMC) schemes, and methods designed specifically for overcoming quasi-ergodicity problems such as Jump Walking (J-Walking), Smart Walking (S-Walking), Smart Darting, and Parallel Tempering. We present an alternative to these approaches that we call Cool Walking, or C-Walking. In C-Walking two Markov chains are propagated in tandem, one at a high (ergodic) temperature and the other at a low temperature. Nonlocal trial moves for the low temperature walker are generated by first sampling from the high-temperature distribution, then performing a statistical quenching process on the sampled configuration to generate a C-Walking jump move. C-Walking needs only one high-temperature walker, satisfies detailed balance, and offers the important practical advantage that the high and low-temperature walkers can be run in tandem with minimal degradation of sampling due to the presence of correlations. To make the C-Walking approach more suitable to real problems we decrease the required number of cooling steps by attempting to jump at intermediate temperatures during cooling. We further reduce the number of cooling steps by utilizing "windows" of states when jumping, which improves acceptance ratios and lowers the average number of cooling steps. We present C-Walking results with comparisons to J-Walking, S-Walking, Smart Darting, and Parallel Tempering on a one-dimensional rugged potential energy surface in which the exact normalized probability distribution is known. C-Walking shows superior sampling as judged by two ergodic measures.

  16. RAPID SEPARATION METHOD FOR ACTINIDES IN EMERGENCY AIR FILTER SAMPLES

    SciTech Connect

    Maxwell, S.; Noyes, G.; Culligan, B.

    2010-02-03

    A new rapid method for the determination of actinides and strontium in air filter samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used in emergency response situations. The actinides and strontium in air filter method utilizes a rapid acid digestion method and a streamlined column separation process with stacked TEVA, TRU and Sr Resin cartridges. Vacuum box technology and rapid flow rates are used to reduce analytical time. Alpha emitters are prepared using cerium fluoride microprecipitation for counting by alpha spectrometry. The purified {sup 90}Sr fractions are mounted directly on planchets and counted by gas flow proportional counting. The method showed high chemical recoveries and effective removal of interferences. This new procedure was applied to emergency air filter samples received in the NRIP Emergency Response exercise administered by the National Institute for Standards and Technology (NIST) in April, 2009. The actinide and {sup 90}Sr in air filter results were reported in {approx}4 hours with excellent quality.

  17. Neutron Activation Analysis of Soil Samples from Different Parts of Edirne in Turkey*

    NASA Astrophysics Data System (ADS)

    Zaim, N.; Dogan, C.; Camtakan, Z.

    2016-05-01

    The concentrations of constituent elements were determined in soil samples collected from different parts of the Maritza Basin, Edirne, Turkey. Neutron activation analysis, an extremely accurate technique, and the comparator method (using a standard) were applied for the first time in this region. After preparing the soil samples for neutron activation analysis, they were activated with thermal neutrons in a nuclear reactor, TRIGA-MARK II, at Istanbul Technical University. The activated samples were analyzed using a high-efficiency high-purity germanium detector, and gamma spectrometry was employed to determine the elemental concentration in the samples. Eight elements (chromium, manganese, cobalt, zinc, arsenic, molybdenum, cadmium, and barium) were qualitatively and quantitatively identified in 36 samples. The concentrations of some elements in the soil samples were high compared with values reported in the literature.

  18. Hand held sample tube manipulator, system and method

    DOEpatents

    Kenny, Donald V [Liberty Township, OH; Smith, Deborah L [Liberty Township, OH; Severance, Richard A [late of Columbus, OH

    2001-01-01

    A manipulator apparatus, system and method for measuring analytes present in sample tubes. The manipulator apparatus includes a housing having a central bore with an inlet end and outlet end; a plunger mechanism with at least a portion thereof slideably disposed for reciprocal movement within the central bore, the plunger mechanism having a tubular gas channel with an inlet end and an outlet end, the gas channel inlet end disposed in the same direction as said inlet end of the central bore, wherein the inlet end of said plunger mechanism is adapted for movement so as to expel a sample tube inserted in the bore at the outlet end of the housing, the inlet end of the plunger mechanism is adapted for connection to gas supply; a first seal is disposed in the housing for sealing between the central bore and the plunger mechanism; a second seal is disposed at the outlet end of the housing for sealing between the central bore and a sample tube; a holder mounted on the housing for holding the sample tube; and a biasing mechanism for returning the plunger mechanism to a starting position.

  19. [A membrane filter sampling method for determining microbial air pollution].

    PubMed

    Cherneva, P; Kiranova, A

    1996-01-01

    The method is a contribution in the evaluation of the exposition and the control of the standards for organic powders. The method concerns the sample-taking procedure and the analysis-making technique for determining of the concentration of the microbial pollution of the air. It is based on filtering of some amount of air through a membrane filter which is then processed for cultivating of microbial colonies on its surface. The results are obtained in number of microbial colonies per unit of air. The method presents opportunity to select and vary the filtered volume of air, to determine the respirable fraction, to determine the personal exposition, as well as for the simultaneous determining of the microbial pollution together with other important parameters of the particle pollutants of the air (metal, fibre and others).

  20. A Novel Method for Sampling Alpha-Helical Protein Backbones

    DOE R&D Accomplishments Database

    Fain, Boris; Levitt, Michael

    2001-01-01

    We present a novel technique of sampling the configurations of helical proteins. Assuming knowledge of native secondary structure, we employ assembly rules gathered from a database of existing structures to enumerate the geometrically possible 3-D arrangements of the constituent helices. We produce a library of possible folds for 25 helical protein cores. In each case the method finds significant numbers of conformations close to the native structure. In addition we assign coordinates to all atoms for 4 of the 25 proteins. In the context of database driven exhaustive enumeration our method performs extremely well, yielding significant percentages of structures (0.02%--82%) within 6A of the native structure. The method's speed and efficiency make it a valuable contribution towards the goal of predicting protein structure.

  1. Methods for parasitic protozoans detection in the environmental samples.

    PubMed

    Skotarczak, B

    2009-09-01

    The environmental route of transmission of many parasitic protozoa and their potential for producing large numbers of transmissive stages constitute persistent threats to public and veterinary health. Conventional and new immunological and molecular methods enable to assess the occurrence, prevalence, levels and sources of waterborne protozoa. Concentration, purification, and detection are the three key steps in all methods that have been approved for routine monitoring of waterborne cysts and oocysts. These steps have been optimized to such an extent that low levels of naturally occurring (oo)cysts of protozoan can be efficiently recovered from water. Ten years have passed since the United States Environmental Protection Agency (USEPA) introduced the 1622 and 1623 methods and used them to concentrate and detect the oocysts of Cryptosporidium and cysts of Giardia in water samples. Nevertheless, the methods still need studies and improvements. Pre-PCR processing procedures have been developed and they are still improved to remove or reduce the effects of PCR inhibitors. The progress in molecular methods allows to more precise distinction of species or simultaneous detection of several parasites, however, they are still not routinely used and need standardization. Standardized methods are required to maximize public health surveillance.

  2. Path Sampling Methods for Enzymatic Quantum Particle Transfer Reactions.

    PubMed

    Dzierlenga, M W; Varga, M J; Schwartz, S D

    2016-01-01

    The mechanisms of enzymatic reactions are studied via a host of computational techniques. While previous methods have been used successfully, many fail to incorporate the full dynamical properties of enzymatic systems. This can lead to misleading results in cases where enzyme motion plays a significant role in the reaction coordinate, which is especially relevant in particle transfer reactions where nuclear tunneling may occur. In this chapter, we outline previous methods, as well as discuss newly developed dynamical methods to interrogate mechanisms of enzymatic particle transfer reactions. These new methods allow for the calculation of free energy barriers and kinetic isotope effects (KIEs) with the incorporation of quantum effects through centroid molecular dynamics (CMD) and the full complement of enzyme dynamics through transition path sampling (TPS). Recent work, summarized in this chapter, applied the method for calculation of free energy barriers to reaction in lactate dehydrogenase (LDH) and yeast alcohol dehydrogenase (YADH). We found that tunneling plays an insignificant role in YADH but plays a more significant role in LDH, though not dominant over classical transfer. Additionally, we summarize the application of a TPS algorithm for the calculation of reaction rates in tandem with CMD to calculate the primary H/D KIE of YADH from first principles. We found that the computationally obtained KIE is within the margin of error of experimentally determined KIEs and corresponds to the KIE of particle transfer in the enzyme. These methods provide new ways to investigate enzyme mechanism with the inclusion of protein and quantum dynamics.

  3. Miniaturized sample preparation method for determination of amphetamines in urine.

    PubMed

    Nishida, Manami; Namera, Akira; Yashiki, Mikio; Kimura, Kojiro

    2004-07-16

    A simple and miniaturized sample preparation method for determination of amphetamines in urine was developed using on-column derivatization and gas chromatography-mass spectrometry (GC-MS). Urine was directly applied to the extraction column that was pre-packed with Extrelut and sodium carbonate. Amphetamine (AP) and methamphetamine (MA) in urine were adsorbed on the surface of Extrelut. AP and MA were then converted to a free base and derivatized to N-propoxycarbonyl derivatives using propylchloroformate on the column. Pentadeuterated MA was used as an internal standard. The recoveries of AP and MA from urine were 100 and 102%, respectively. The calibration curves showed linearity in the range of 0.50-50 microg/mL for AP and MA in urine. When urine samples containing two different concentrations (0.50 and 5.0 microg/mL) of AP and MA were determined, the intra-day and inter-day coefficients of variation were 1.4-7.7%. This method was applied to 14 medico-legal cases of MA intoxication. The results were compared and a good agreement was obtained with a HPLC method.

  4. Vadose Zone Sampling Methods for Detection of Preferential Pesticides Transport

    NASA Astrophysics Data System (ADS)

    Peranginangin, N.; Richards, B. K.; Steenhuis, T. S.

    2003-12-01

    Leaching of agricultural applied chemicals through the vadose zone is a major cause for the occurrence of agrichemicals in groundwater. Accurate soil water sampling methods are needed to ensure meaningful monitoring results, especially for soils that have significant preferential flow paths. The purpose of this study was to assess the capability and the effectiveness of various soil water sampling methods in detecting preferential transport of pesticides in a strongly-structured silty clay loam (Hudson series) soil. Soil water sampling devices tested were wick pan and gravity pan lysimeters, tile lines, porous ceramic cups, and pipe lysimeters; all installed at 45 to105 cm depth below the ground surface. A reasonable worse-case scenario was tested by applying a simulated rain storm soon after pesticides were sprayed at agronomic rates. Herbicides atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) and 2,4-D (2,4-dichloro-phenoxyacetic acid) were chosen as model compounds. Chloride (KCl) tracer was used to determine spatial and temporal distribution of non-reactive solute and water as well as a basis for determining the retardation in pesticides movement. Results show that observed pesticide mobility was much greater than would be predicted by uniform flow. Under relatively high soil moisture conditions, gravity and wick pan lysimeters had comparably good collection efficiencies, whereas the wick samplers had an advantage over gravity driven sampler when the soil moisture content was below field capacity. Pipe lysimeters had breakthrough patterns that were similar to pan samplers. At small plot scale, tile line samplers tended to underestimate solute concentration because of water dilution around the samplers. The use of porous cup samplers performed poorly because of their sensitivity to local profile characteristics: only by chance can they intercept and sample the preferential flow paths that are critical to transport. Wick sampler had the least

  5. Determining the phagocytic activity of clinical antibody samples.

    PubMed

    McAndrew, Elizabeth G; Dugast, Anne-Sophie; Licht, Anna F; Eusebio, Justin R; Alter, Galit; Ackerman, Margaret E

    2011-11-30

    Antibody-driven phagocytosis is induced via the engagement of Fc receptors on professional phagocytes, and can contribute to both clearance as well as pathology of disease. While the properties of the variable domains of antibodies have long been considered critical to in vivo function, the ability of antibodies to recruit innate immune cells via their Fc domains has become increasingly appreciated as a major factor in their efficacy, both in the setting of recombinant monoclonal antibody therapy, as well as in the course of natural infection or vaccination(1-3). Importantly, despite its nomenclature as a constant domain, the antibody Fc domain does not have constant function, and is strongly modulated by IgG subclass (IgG1-4) and glycosylation at Asparagine 297(4-6). Thus, this method to study functional differences of antigen-specific antibodies in clinical samples will facilitate correlation of the phagocytic potential of antibodies to disease state, susceptibility to infection, progression, or clinical outcome. Furthermore, this effector function is particularly important in light of the documented ability of antibodies to enhance infection by providing pathogens access into host cells via Fc receptor-driven phagocytosis(7). Additionally, there is some evidence that phagocytic uptake of immune complexes can impact the Th1/Th2 polarization of the immune response(8). Here, we describe an assay designed to detect differences in antibody-induced phagocytosis, which may be caused by differential IgG subclass, glycan structure at Asn297, as well as the ability to form immune complexes of antigen-specific antibodies in a high-throughput fashion. To this end, 1 μm fluorescent beads are coated with antigen, then incubated with clinical antibody samples, generating fluorescent antigen specific immune complexes. These antibody-opsonized beads are then incubated with a monocytic cell line expressing multiple FcγRs, including both inhibitory and activating. Assay output

  6. Several methods for concentrating bacteria in fluid samples

    NASA Technical Reports Server (NTRS)

    Thomas, R. R.

    1976-01-01

    The sensitivities of the firefly luciferase - ATP flow system and luminol flow system were established as 300,000 E. coli per milliliter and 10,000 E. coli per milliliter respectively. To achieve the detection limit of 1,000 bacteria per milliliter previously established, a method of concentrating microorganisms using a sartorius membrane filter system is investigated. Catalase in 50% ethanol is found to be a stable luminol standard and can be used up to 24 hours with only a 10% loss of activity. The luminol reagent is also stable over a 24 hour period. A method of preparing relatively inexpensive luciferase from desiccated firefly tails is developed.

  7. Drum plug piercing and sampling device and method

    DOEpatents

    Counts, Kevin T.

    2011-04-26

    An apparatus and method for piercing a drum plug of a drum in order to sample and/or vent gases that may accumulate in a space of the drum is provided. The drum is not damaged and can be reused since the pierced drum plug can be subsequently replaced. The apparatus includes a frame that is configured for engagement with the drum. A cylinder actuated by a fluid is mounted to the frame. A piercer is placed into communication with the cylinder so that actuation of the cylinder causes the piercer to move in a linear direction so that the piercer may puncture the drum plug of the drum.

  8. A GPU code for analytic continuation through a sampling method

    NASA Astrophysics Data System (ADS)

    Nordström, Johan; Schött, Johan; Locht, Inka L. M.; Di Marco, Igor

    We here present a code for performing analytic continuation of fermionic Green's functions and self-energies as well as bosonic susceptibilities on a graphics processing unit (GPU). The code is based on the sampling method introduced by Mishchenko et al. (2000), and is written for the widely used CUDA platform from NVidia. Detailed scaling tests are presented, for two different GPUs, in order to highlight the advantages of this code with respect to standard CPU computations. Finally, as an example of possible applications, we provide the analytic continuation of model Gaussian functions, as well as more realistic test cases from many-body physics.

  9. INVESTIGATION OF THE TOTAL ORGANIC HALOGEN ANALYTICAL METHOD AT THE WASTE SAMPLING CHARACTERIZATION FACILITY (WSCF)

    SciTech Connect

    DOUGLAS JG; MEZNARICH HD, PHD; OLSEN JR; ROSS GA; STAUFFER M

    2008-09-30

    Total organic halogen (TOX) is used as a parameter to screen groundwater samples at the Hanford Site. Trending is done for each groundwater well, and changes in TOX and other screening parameters can lead to costly changes in the monitoring protocol. The Waste Sampling and Characterization Facility (WSCF) analyzes groundwater samples for TOX using the United States Environmental Protection Agency (EPA) SW-846 method 9020B (EPA 1996a). Samples from the Soil and Groundwater Remediation Project (S&GRP) are submitted to the WSCF for analysis without information regarding the source of the sample; each sample is in essence a 'blind' sample to the laboratory. Feedback from the S&GRP indicated that some of the WSCF-generated TOX data from groundwater wells had a number of outlier values based on the historical trends (Anastos 2008a). Additionally, analysts at WSCF observed inconsistent TOX results among field sample replicates. Therefore, the WSCF lab performed an investigation of the TOX analysis to determine the cause of the outlier data points. Two causes were found that contributed to generating out-of-trend TOX data: (1) The presence of inorganic chloride in the groundwater samples: at inorganic chloride concentrations greater than about 10 parts per million (ppm), apparent TOX values increase with increasing chloride concentration. A parallel observation is the increase in apparent breakthrough of TOX from the first to the second activated-carbon adsorption tubes with increasing inorganic chloride concentration. (2) During the sample preparation step, excessive purging of the adsorption tubes with oxygen pressurization gas after sample loading may cause channeling in the activated-carbon bed. This channeling leads to poor removal of inorganic chloride during the subsequent wash step with aqueous potassium nitrate. The presence of this residual inorganic chloride then produces erroneously high TOX values. Changes in sample preparation were studied to more effectively

  10. Sample Size for Assessing Agreement between Two Methods of Measurement by Bland-Altman Method.

    PubMed

    Lu, Meng-Jie; Zhong, Wei-Hua; Liu, Yu-Xiu; Miao, Hua-Zhang; Li, Yong-Chang; Ji, Mu-Huo

    2016-11-01

    The Bland-Altman method has been widely used for assessing agreement between two methods of measurement. However, it remains unsolved about sample size estimation. We propose a new method of sample size estimation for Bland-Altman agreement assessment. According to the Bland-Altman method, the conclusion on agreement is made based on the width of the confidence interval for LOAs (limits of agreement) in comparison to predefined clinical agreement limit. Under the theory of statistical inference, the formulae of sample size estimation are derived, which depended on the pre-determined level of α, β, the mean and the standard deviation of differences between two measurements, and the predefined limits. With this new method, the sample sizes are calculated under different parameter settings which occur frequently in method comparison studies, and Monte-Carlo simulation is used to obtain the corresponding powers. The results of Monte-Carlo simulation showed that the achieved powers could coincide with the pre-determined level of powers, thus validating the correctness of the method. The method of sample size estimation can be applied in the Bland-Altman method to assess agreement between two methods of measurement.

  11. Eigenvector method for umbrella sampling enables error analysis.

    PubMed

    Thiede, Erik H; Van Koten, Brian; Weare, Jonathan; Dinner, Aaron R

    2016-08-28

    Umbrella sampling efficiently yields equilibrium averages that depend on exploring rare states of a model by biasing simulations to windows of coordinate values and then combining the resulting data with physical weighting. Here, we introduce a mathematical framework that casts the step of combining the data as an eigenproblem. The advantage to this approach is that it facilitates error analysis. We discuss how the error scales with the number of windows. Then, we derive a central limit theorem for averages that are obtained from umbrella sampling. The central limit theorem suggests an estimator of the error contributions from individual windows, and we develop a simple and computationally inexpensive procedure for implementing it. We demonstrate this estimator for simulations of the alanine dipeptide and show that it emphasizes low free energy pathways between stable states in comparison to existing approaches for assessing error contributions. Our work suggests the possibility of using the estimator and, more generally, the eigenvector method for umbrella sampling to guide adaptation of the simulation parameters to accelerate convergence.

  12. Method for testing earth samples for contamination by organic contaminants

    DOEpatents

    Schabron, J.F.

    1996-10-01

    Provided is a method for testing earth samples for contamination by organic contaminants, and particularly for aromatic compounds such as those found in diesel fuel and other heavy fuel oils, kerosene, creosote, coal oil, tars and asphalts. A drying step is provided in which a drying agent is contacted with either the earth sample or a liquid extract phase to reduce to possibility of false indications of contamination that could occur when humic material is present in the earth sample. This is particularly a problem when using relatively safe, non-toxic and inexpensive polar solvents such as isopropyl alcohol since the humic material tends to be very soluble in those solvents when water is present. Also provided is an ultraviolet spectroscopic measuring technique for obtaining an indication as to whether a liquid extract phase contains aromatic organic contaminants. In one embodiment, the liquid extract phase is subjected to a narrow and discrete band of radiation including a desired wave length and the ability of the liquid extract phase to absorb that wavelength of ultraviolet radiation is measured to provide an indication of the presence of aromatic organic contaminants. 2 figs.

  13. Method for testing earth samples for contamination by organic contaminants

    DOEpatents

    Schabron, John F.

    1996-01-01

    Provided is a method for testing earth samples for contamination by organic contaminants, and particularly for aromatic compounds such as those found in diesel fuel and other heavy fuel oils, kerosene, creosote, coal oil, tars and asphalts. A drying step is provided in which a drying agent is contacted with either the earth sample or a liquid extract phase to reduce to possibility of false indications of contamination that could occur when humic material is present in the earth sample. This is particularly a problem when using relatively safe, non-toxic and inexpensive polar solvents such as isopropyl alcohol since the humic material tends to be very soluble in those solvents when water is present. Also provided is an ultraviolet spectroscopic measuring technique for obtaining an indication as to whether a liquid extract phase contains aromatic organic contaminants. In one embodiment, the liquid extract phase is subjected to a narrow and discrete band of radiation including a desired wave length and the ability of the liquid extract phase to absorb that wavelength of ultraviolet radiation is measured to provide an indication of the presence of aromatic organic contaminants.

  14. Eigenvector method for umbrella sampling enables error analysis

    NASA Astrophysics Data System (ADS)

    Thiede, Erik H.; Van Koten, Brian; Weare, Jonathan; Dinner, Aaron R.

    2016-08-01

    Umbrella sampling efficiently yields equilibrium averages that depend on exploring rare states of a model by biasing simulations to windows of coordinate values and then combining the resulting data with physical weighting. Here, we introduce a mathematical framework that casts the step of combining the data as an eigenproblem. The advantage to this approach is that it facilitates error analysis. We discuss how the error scales with the number of windows. Then, we derive a central limit theorem for averages that are obtained from umbrella sampling. The central limit theorem suggests an estimator of the error contributions from individual windows, and we develop a simple and computationally inexpensive procedure for implementing it. We demonstrate this estimator for simulations of the alanine dipeptide and show that it emphasizes low free energy pathways between stable states in comparison to existing approaches for assessing error contributions. Our work suggests the possibility of using the estimator and, more generally, the eigenvector method for umbrella sampling to guide adaptation of the simulation parameters to accelerate convergence.

  15. BMAA extraction of cyanobacteria samples: which method to choose?

    PubMed

    Lage, Sandra; Burian, Alfred; Rasmussen, Ulla; Costa, Pedro Reis; Annadotter, Heléne; Godhe, Anna; Rydberg, Sara

    2016-01-01

    β-N-Methylamino-L-alanine (BMAA), a neurotoxin reportedly produced by cyanobacteria, diatoms and dinoflagellates, is proposed to be linked to the development of neurological diseases. BMAA has been found in aquatic and terrestrial ecosystems worldwide, both in its phytoplankton producers and in several invertebrate and vertebrate organisms that bioaccumulate it. LC-MS/MS is the most frequently used analytical technique in BMAA research due to its high selectivity, though consensus is lacking as to the best extraction method to apply. This study accordingly surveys the efficiency of three extraction methods regularly used in BMAA research to extract BMAA from cyanobacteria samples. The results obtained provide insights into possible reasons for the BMAA concentration discrepancies in previous publications. In addition and according to the method validation guidelines for analysing cyanotoxins, the TCA protein precipitation method, followed by AQC derivatization and LC-MS/MS analysis, is now validated for extracting protein-bound (after protein hydrolysis) and free BMAA from cyanobacteria matrix. BMAA biological variability was also tested through the extraction of diatom and cyanobacteria species, revealing a high variance in BMAA levels (0.0080-2.5797 μg g(-1) DW).

  16. Automated Aqueous Sample Concentration Methods for in situ Astrobiological Instrumentation

    NASA Astrophysics Data System (ADS)

    Aubrey, A. D.; Grunthaner, F. J.

    2009-12-01

    The era of wet chemical experiments for in situ planetary science investigations is upon us, as evidenced by recent results from the surface of Mars by Phoenix’s microscopy, electrochemistry, and conductivity analyzer, MECA [1]. Studies suggest that traditional thermal volatilization methods for planetary science in situ investigations induce organic degradation during sample processing [2], an effect that is enhanced in the presence of oxidants [3]. Recent developments have trended towards adaptation of non-destructive aqueous extraction and analytical methods for future astrobiological instrumentation. Wet chemical extraction techniques under investigation include subcritical water extraction, SCWE [4], aqueous microwave assisted extraction, MAE, and organic solvent extraction [5]. Similarly, development of miniaturized analytical space flight instruments that require aqueous extracts include microfluidic capillary electrophoresis chips, μCE [6], liquid-chromatography mass-spectrometrometers, LC-MS [7], and life marker chips, LMC [8]. If organics are present on the surface of Mars, they are expected to be present at extremely low concentrations (parts-per-billion), orders of magnitude below the sensitivities of most flight instrument technologies. Therefore, it becomes necessary to develop and integrate concentration mechanisms for in situ sample processing before delivery to analytical flight instrumentation. We present preliminary results of automated solid-phase-extraction (SPE) sample purification and concentration methods for the treatment of highly saline aqueous soil extracts. These methods take advantage of the affinity of low molecular weight organic compounds with natural and synthetic scavenger materials. These interactions allow for the separation of target organic analytes from unfavorable background species (i.e. salts) during inline treatment, and a clever method for selective desorption is utilized to obtain concentrated solutions on the order

  17. 19 CFR 151.70 - Method of sampling by Customs.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... THE TREASURY (CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.70... feasible to obtain a representative general sample of the wool or hair in a sampling unit or to test such...

  18. 19 CFR 151.70 - Method of sampling by Customs.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... THE TREASURY (CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.70... feasible to obtain a representative general sample of the wool or hair in a sampling unit or to test such...

  19. 19 CFR 151.70 - Method of sampling by Customs.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... THE TREASURY (CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.70... feasible to obtain a representative general sample of the wool or hair in a sampling unit or to test such...

  20. 19 CFR 151.70 - Method of sampling by Customs.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... THE TREASURY (CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.70... feasible to obtain a representative general sample of the wool or hair in a sampling unit or to test such...

  1. 19 CFR 151.70 - Method of sampling by Customs.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... THE TREASURY (CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.70... feasible to obtain a representative general sample of the wool or hair in a sampling unit or to test such...

  2. Comparative study of activation analyses for the determination of trace halogens in geological and cosmochemical samples.

    PubMed

    Nakamoto, Tomoshi; Oura, Yasuji; Ebihara, Mitsuru

    2007-09-01

    Halogens (fluorine, chlorine, bromine and iodine) were determined by activation analyses (neutron activation analysis (NAA), photon activation analysis (PAA) and prompt gamma-ray analysis (PGA)) for geological and cosmochemical solid samples. We studied how each analytical method was for the determination of trace amounts of halogens in rock samples. Radiochemical NAA (RNAA) showed the highest analytical reliability for three halogens (chlorine, bromine and iodine), whereas a set of four halogens (fluorine, chlorine, bromine and iodine) could be determined in principle by radiochemical PAA (RPAA) from a single specimen. Although it is a non-destructive method, PGA showed an analytical sensitivity for chlorine comparable to those of RNAA and RPAA.

  3. Comparison of blood chemistry values for samples collected from juvenile chinook salmon by three methods

    USGS Publications Warehouse

    Congleton, J.L.; LaVoie, W.J.

    2001-01-01

    Thirteen blood chemistry indices were compared for samples collected by three commonly used methods: caudal transection, heart puncture, and caudal vessel puncture. Apparent biases in blood chemistry values for samples obtained by caudal transection were consistent with dilution with tissue fluids: alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), triglyceride, and K+ were increased and Na+ and Cl- were decreased relative to values for samples obtained by caudal vessel puncture. Some enzyme activities (ALT, AST, LDH) and K+ concentrations were also greater in samples taken by heart puncture than in samples taken by caudal vessel puncture. Of the methods tested, caudal vessel puncture had the least effect on blood chemistry values and should be preferred for blood chemistry studies on juvenile salmonids.

  4. Active sample acquisition system for micro-penetrators

    NASA Astrophysics Data System (ADS)

    Voorhees, Chris; Potsaid, Benjamin

    1998-05-01

    This paper summarizes the design and development of a sub-surface sample acquisition system for use in micro-penetrators. The system was developed for flight use under NASA's New Millennium Program, Deep Space 2 project. The system goal is to acquire approximately 100 mg of Martian sub-surface soil and return it to the inside of the micro-penetrator for analysis to determine the presence of water. Various passive and active sampling techniques that were tested during the development cycle are described. After significant testing, a side bore drill mechanism was chosen to be developed for use in the flight penetrators. The design, development, and testing of mechanism element are outlined, with particular emphasis placed on actuator development, drill stem design, impact testing, and mechanism testing in various soil types. The other system elements, a pyrotechnically actuated door mechanism to seal the sample and an impact restraint mechanism, are also described.

  5. Enhanced activities of organically bound tritium in biota samples.

    PubMed

    Svetlik, I; Fejgl, M; Malátová, I; Tomaskova, L

    2014-11-01

    A pilot study aimed on possible occurrence of elevated activity of non-exchangable organically bound tritium (NE-OBT) in biota was performed. The first results showed a significant surplus of NE-OBT activity in biota of the valley of Mohelno reservoir and Jihlava river. The liquid releases of HTO from the nuclear power plant Dukovany is the source of tritium in this area. This area can be a source of various types of natural samples for future studies of tritium pathways.

  6. Clustering Methods with Qualitative Data: a Mixed-Methods Approach for Prevention Research with Small Samples.

    PubMed

    Henry, David; Dymnicki, Allison B; Mohatt, Nathaniel; Allen, James; Kelly, James G

    2015-10-01

    Qualitative methods potentially add depth to prevention research but can produce large amounts of complex data even with small samples. Studies conducted with culturally distinct samples often produce voluminous qualitative data but may lack sufficient sample sizes for sophisticated quantitative analysis. Currently lacking in mixed-methods research are methods allowing for more fully integrating qualitative and quantitative analysis techniques. Cluster analysis can be applied to coded qualitative data to clarify the findings of prevention studies by aiding efforts to reveal such things as the motives of participants for their actions and the reasons behind counterintuitive findings. By clustering groups of participants with similar profiles of codes in a quantitative analysis, cluster analysis can serve as a key component in mixed-methods research. This article reports two studies. In the first study, we conduct simulations to test the accuracy of cluster assignment using three different clustering methods with binary data as produced when coding qualitative interviews. Results indicated that hierarchical clustering, K-means clustering, and latent class analysis produced similar levels of accuracy with binary data and that the accuracy of these methods did not decrease with samples as small as 50. Whereas the first study explores the feasibility of using common clustering methods with binary data, the second study provides a "real-world" example using data from a qualitative study of community leadership connected with a drug abuse prevention project. We discuss the implications of this approach for conducting prevention research, especially with small samples and culturally distinct communities.

  7. Optimizing Estimated Loss Reduction for Active Sampling in Rank Learning

    DTIC Science & Technology

    2008-01-01

    ranging from the income level to age and her preference order over a set of products (e.g. movies in Netflix ). The ranking task is to learn a map- ping...learners in RankBoost. However, in both cases, the proposed strategy selects the samples which are estimated to produce a faster convergence from the...steps in Section 5. 2. Related Work A number of strategies have been proposed for active learning in the classification framework. Some of those center

  8. Improved transition path sampling methods for simulation of rare events.

    PubMed

    Chopra, Manan; Malshe, Rohit; Reddy, Allam S; de Pablo, J J

    2008-04-14

    The free energy surfaces of a wide variety of systems encountered in physics, chemistry, and biology are characterized by the existence of deep minima separated by numerous barriers. One of the central aims of recent research in computational chemistry and physics has been to determine how transitions occur between deep local minima on rugged free energy landscapes, and transition path sampling (TPS) Monte-Carlo methods have emerged as an effective means for numerical investigation of such transitions. Many of the shortcomings of TPS-like approaches generally stem from their high computational demands. Two new algorithms are presented in this work that improve the efficiency of TPS simulations. The first algorithm uses biased shooting moves to render the sampling of reactive trajectories more efficient. The second algorithm is shown to substantially improve the accuracy of the transition state ensemble by introducing a subset of local transition path simulations in the transition state. The system considered in this work consists of a two-dimensional rough energy surface that is representative of numerous systems encountered in applications. When taken together, these algorithms provide gains in efficiency of over two orders of magnitude when compared to traditional TPS simulations.

  9. A comparison of methods for representing sparsely sampled random quantities.

    SciTech Connect

    Romero, Vicente Jose; Swiler, Laura Painton; Urbina, Angel; Mullins, Joshua

    2013-09-01

    This report discusses the treatment of uncertainties stemming from relatively few samples of random quantities. The importance of this topic extends beyond experimental data uncertainty to situations involving uncertainty in model calibration, validation, and prediction. With very sparse data samples it is not practical to have a goal of accurately estimating the underlying probability density function (PDF). Rather, a pragmatic goal is that the uncertainty representation should be conservative so as to bound a specified percentile range of the actual PDF, say the range between 0.025 and .975 percentiles, with reasonable reliability. A second, opposing objective is that the representation not be overly conservative; that it minimally over-estimate the desired percentile range of the actual PDF. The presence of the two opposing objectives makes the sparse-data uncertainty representation problem interesting and difficult. In this report, five uncertainty representation techniques are characterized for their performance on twenty-one test problems (over thousands of trials for each problem) according to these two opposing objectives and other performance measures. Two of the methods, statistical Tolerance Intervals and a kernel density approach specifically developed for handling sparse data, exhibit significantly better overall performance than the others.

  10. PerPAS: Topology-Based Single Sample Pathway Analysis Method.

    PubMed

    Liu, Chengyu; Lehtonen, Rainer; Hautaniemi, Sampsa

    2017-03-08

    Identification of intracellular pathways that play key roles in cancer progression and drug resistance is a prerequisite for developing targeted cancer treatments. The era of personalized medicine calls for computational methods that can function with one sample or very small set of samples. Developing such methods is challenging because standard statistical approaches pose several limiting assumptions, such as number of samples, that prevent their application when n approaches to one. We have developed a novel pathway analysis method called PerPAS to estimate pathway activity at a single sample level by integrating pathway topology and transcriptomics data. In addition, PerPAS is able to identify altered pathways between cancer and control samples as well as to identify key nodes that contribute to the pathway activity. In our case study using breast cancer data, we show that PerPAS can identify highly altered pathways that are associated with patient survival. PerPAS identified four pathways that were associated with patient survival and were successfully validated in three independent breast cancer cohorts. In comparison to two other pathway analysis methods that function at a single sample level, PerPAS had superior performance in both synthetic and breast cancer expression datasets. PerPAS is a free R package (http://csbi.ltdk.helsinki.fi/pub/czliu/perpas/).

  11. Experience-Sampling Research Methods and Their Potential for Education Research

    ERIC Educational Resources Information Center

    Zirkel, Sabrina; Garcia, Julie A.; Murphy, Mary C.

    2015-01-01

    Experience-sampling methods (ESM) enable us to learn about individuals' lives in context by measuring participants' feelings, thoughts, actions, context, and/or activities as they go about their daily lives. By capturing experience, affect, and action "in the moment" and with repeated measures, ESM approaches allow researchers…

  12. COMPARISON OF SAMPLING METHODS FOR SEMI-VOLATILE ORGANIC CARBON ASSOCIATED WITH PM 2.5

    EPA Science Inventory

    This study evaluates the influence of denuder sampling methods and filter collection media on the measurement of semi-volatile organic carbon (SVOC) associated with PM2.5. Two types of collection media, charcoal (activated carbon) and XAD, were used both in diffusion denuders ...

  13. A simple capacitive method to evaluate ethanol fuel samples

    NASA Astrophysics Data System (ADS)

    Vello, Tatiana P.; de Oliveira, Rafael F.; Silva, Gustavo O.; de Camargo, Davi H. S.; Bufon, Carlos C. B.

    2017-02-01

    Ethanol is a biofuel used worldwide. However, the presence of excessive water either during the distillation process or by fraudulent adulteration is a major concern in the use of ethanol fuel. High water levels may cause engine malfunction, in addition to being considered illegal. Here, we describe the development of a simple, fast and accurate platform based on nanostructured sensors to evaluate ethanol samples. The device fabrication is facile, based on standard microfabrication and thin-film deposition methods. The sensor operation relies on capacitance measurements employing a parallel plate capacitor containing a conformational aluminum oxide (Al2O3) thin layer (15 nm). The sensor operates over the full range water concentration, i.e., from approximately 0% to 100% vol. of water in ethanol, with water traces being detectable down to 0.5% vol. These characteristics make the proposed device unique with respect to other platforms. Finally, the good agreement between the sensor response and analyses performed by gas chromatography of ethanol biofuel endorses the accuracy of the proposed method. Due to the full operation range, the reported sensor has the technological potential for use as a point-of-care analytical tool at gas stations or in the chemical, pharmaceutical, and beverage industries, to mention a few.

  14. A simple capacitive method to evaluate ethanol fuel samples

    PubMed Central

    Vello, Tatiana P.; de Oliveira, Rafael F.; Silva, Gustavo O.; de Camargo, Davi H. S.; Bufon, Carlos C. B.

    2017-01-01

    Ethanol is a biofuel used worldwide. However, the presence of excessive water either during the distillation process or by fraudulent adulteration is a major concern in the use of ethanol fuel. High water levels may cause engine malfunction, in addition to being considered illegal. Here, we describe the development of a simple, fast and accurate platform based on nanostructured sensors to evaluate ethanol samples. The device fabrication is facile, based on standard microfabrication and thin-film deposition methods. The sensor operation relies on capacitance measurements employing a parallel plate capacitor containing a conformational aluminum oxide (Al2O3) thin layer (15 nm). The sensor operates over the full range water concentration, i.e., from approximately 0% to 100% vol. of water in ethanol, with water traces being detectable down to 0.5% vol. These characteristics make the proposed device unique with respect to other platforms. Finally, the good agreement between the sensor response and analyses performed by gas chromatography of ethanol biofuel endorses the accuracy of the proposed method. Due to the full operation range, the reported sensor has the technological potential for use as a point-of-care analytical tool at gas stations or in the chemical, pharmaceutical, and beverage industries, to mention a few. PMID:28240312

  15. MARKOV CHAIN MONTE CARLO POSTERIOR SAMPLING WITH THE HAMILTONIAN METHOD

    SciTech Connect

    K. HANSON

    2001-02-01

    The Markov Chain Monte Carlo technique provides a means for drawing random samples from a target probability density function (pdf). MCMC allows one to assess the uncertainties in a Bayesian analysis described by a numerically calculated posterior distribution. This paper describes the Hamiltonian MCMC technique in which a momentum variable is introduced for each parameter of the target pdf. In analogy to a physical system, a Hamiltonian H is defined as a kinetic energy involving the momenta plus a potential energy {var_phi}, where {var_phi} is minus the logarithm of the target pdf. Hamiltonian dynamics allows one to move along trajectories of constant H, taking large jumps in the parameter space with relatively few evaluations of {var_phi} and its gradient. The Hamiltonian algorithm alternates between picking a new momentum vector and following such trajectories. The efficiency of the Hamiltonian method for multidimensional isotropic Gaussian pdfs is shown to remain constant at around 7% for up to several hundred dimensions. The Hamiltonian method handles correlations among the variables much better than the standard Metropolis algorithm. A new test, based on the gradient of {var_phi}, is proposed to measure the convergence of the MCMC sequence.

  16. Spline methods for approximating quantile functions and generating random samples

    NASA Technical Reports Server (NTRS)

    Schiess, J. R.; Matthews, C. G.

    1985-01-01

    Two cubic spline formulations are presented for representing the quantile function (inverse cumulative distribution function) of a random sample of data. Both B-spline and rational spline approximations are compared with analytic representations of the quantile function. It is also shown how these representations can be used to generate random samples for use in simulation studies. Comparisons are made on samples generated from known distributions and a sample of experimental data. The spline representations are more accurate for multimodal and skewed samples and to require much less time to generate samples than the analytic representation.

  17. Parametric estimation of sample entropy for physical activity recognition.

    PubMed

    Aktaruzzaman, Md; Scarabottolo, Nello; Sassi, Roberto

    2015-08-01

    Insufficient amount of physical activity, and hence storage of calories may lead depression, obesity, cardiovascular diseases, and diabetes. The amount of consumed calorie depends on the type of activity. The recognition of physical activity is very important to estimate the amount of calories spent by a subject every day. There are some research works already published in the literature for activity recognition through accelerometers (body worn sensors). The accuracy of any recognition system depends on the robustness of selected features and classifiers. The typical features reported for most physical activities recognitions are autoregressive coefficients (ARcoeffs), signal magnitude area (SMA), tilt angle (TA), and standard deviation (STD). In this study, we have studied the feasibility of using single value of sample entropy estimated parametrically (SETH) of an AR model instead of ARcoeffs. After feasibility study, we also compared the recognition accuracies between two popular classifiers ı.e. artificial neural network (ANN) and support vector machines (SVM). The recognition accuracies using linear structure (where all types of activities are classified using a single classifier) and hierarchical structure (where activities are first divided into static and dynamic events, and then activities of each event are classified in the second stage). The study showed that the use of SETH provides similar recognition accuracy (69.82%) as provided by ARcoeffs (67.67%) using ANN. The linear structure of SVM performs better (average accuracy of SVM: 98.22%) than linear ANN (average accuracy with ANN: 94.78%). The use of hierarchical structure of ANN increases the average recognition accuracy of static activities to about 100%. However, no significant changes are observed using hierarchical SVM than the linear one.

  18. Sequential sampling: a novel method in farm animal welfare assessment.

    PubMed

    Heath, C A E; Main, D C J; Mullan, S; Haskell, M J; Browne, W J

    2016-02-01

    Lameness in dairy cows is an important welfare issue. As part of a welfare assessment, herd level lameness prevalence can be estimated from scoring a sample of animals, where higher levels of accuracy are associated with larger sample sizes. As the financial cost is related to the number of cows sampled, smaller samples are preferred. Sequential sampling schemes have been used for informing decision making in clinical trials. Sequential sampling involves taking samples in stages, where sampling can stop early depending on the estimated lameness prevalence. When welfare assessment is used for a pass/fail decision, a similar approach could be applied to reduce the overall sample size. The sampling schemes proposed here apply the principles of sequential sampling within a diagnostic testing framework. This study develops three sequential sampling schemes of increasing complexity to classify 80 fully assessed UK dairy farms, each with known lameness prevalence. Using the Welfare Quality herd-size-based sampling scheme, the first 'basic' scheme involves two sampling events. At the first sampling event half the Welfare Quality sample size is drawn, and then depending on the outcome, sampling either stops or is continued and the same number of animals is sampled again. In the second 'cautious' scheme, an adaptation is made to ensure that correctly classifying a farm as 'bad' is done with greater certainty. The third scheme is the only scheme to go beyond lameness as a binary measure and investigates the potential for increasing accuracy by incorporating the number of severely lame cows into the decision. The three schemes are evaluated with respect to accuracy and average sample size by running 100 000 simulations for each scheme, and a comparison is made with the fixed size Welfare Quality herd-size-based sampling scheme. All three schemes performed almost as well as the fixed size scheme but with much smaller average sample sizes. For the third scheme, an overall

  19. Probing methane hydrate nucleation through the forward flux sampling method.

    PubMed

    Bi, Yuanfei; Li, Tianshu

    2014-11-26

    Understanding the nucleation of hydrate is the key to developing effective strategies for controlling methane hydrate formation. Here we present a computational study of methane hydrate nucleation, by combining the forward flux sampling (FFS) method and the coarse-grained water model mW. To facilitate the application of FFS in studying the formation of methane hydrate, we developed an effective order parameter λ on the basis of the topological analysis of the tetrahedral network. The order parameter capitalizes the signature of hydrate structure, i.e., polyhedral cages, and is capable of efficiently distinguishing hydrate from ice and liquid water while allowing the formation of different hydrate phases, i.e., sI, sII, and amorphous. Integration of the order parameter λ with FFS allows explicitly computing hydrate nucleation rates and obtaining an ensemble of nucleation trajectories under conditions where spontaneous hydrate nucleation becomes too slow to occur in direct simulation. The convergence of the obtained hydrate nucleation rate was found to depend crucially on the convergence of the spatial distribution for the spontaneously formed hydrate seeds obtained from the initial sampling of FFS. The validity of the approach is also verified by the agreement between the calculated nucleation rate and that inferred from the direct simulation. Analyzing the obtained large ensemble of hydrate nucleation trajectories, we show hydrate formation at 220 K and 500 bar is initiated by the nucleation events occurring in the vicinity of water-methane interface, and facilitated by a gradual transition from amorphous to crystalline structure. The latter provides the direct support to the proposed two-step nucleation mechanism of methane hydrate.

  20. Determination of rare-earth elements in Luna 16 regolith sample by chemical spectral method

    NASA Technical Reports Server (NTRS)

    Stroganova, N. S.; Ryabukhin, V. A.; Laktinova, N. V.; Ageyeva, L. V.; Galkina, I. P.; Gatinskaya, N. G.; Yermakov, A. N.; Karyakin, A. V.

    1974-01-01

    An analysis was made of regolith from layer A of the Luna 16 sample for rare earth elements, by a chemical spectral method. Chemical and ion exchange concentrations were used to determine the content of 12 elements and Y at the level 0.001 to 0.0001 percent with 10 to 15 percent reproducibility of the emission determination. Results within the limits of reproducibility agree with data obtained by mass spectra, activation, and X-ray fluorescent methods.

  1. COMPARISON OF USEPA FIELD SAMPLING METHODS FOR BENTHIC MACROINVERTEBRATE STUDIES

    EPA Science Inventory

    Two U.S. Environmental Protection Agency (USEPA) macroinvertebrate sampling protocols were compared in the Mid-Atlantic Highlands region. The Environmental Monitoring and Assessment Program (EMAP) wadeable streams protocol results in a single composite sample from nine transects...

  2. Vegetation Sampling for Wetland Delineation: A Review and Synthesis of Methods and Sampling Issues

    DTIC Science & Technology

    2010-07-01

    bryophytes , can be effectively sampled using much smaller plots (Bonham 1989). The most appropriate size for a sample plot depends on the type of...and, when abundant, provide strong indicators of hydrophytic vegetation (Seppelt et al. 2008; Lichvar et al. 2009). Sampling bryophytes presents...of wetland specialist bryophytes (USACE 2007). In some wetland types, bryophytes may contribute significant floristic diversity and canopy coverage

  3. Comparing citrated native, kaolin-activated, and tissue factor-activated samples and determining intraindividual variability for feline thromboelastography.

    PubMed

    Banerjee, Amrita; Blois, Shauna L; Wood, R Darren

    2011-11-01

    Thromboelastography (TEG) is a point-of-care whole blood test of hemostasis. While TEG is becoming more widely used in veterinary medicine, few studies describe the use of TEG in cats. The objectives of the current study were to: 1) document the range of TEG variables produced in healthy cats using 3 sample types (citrated native, kaolin-activated, and tissue factor-activated), and 2) determine if there was a significant difference between 2 separate samples obtained from individual healthy cats on the same day. Jugular venipuncture was performed in 20 cats, and citrated blood collected for TEG. TEG analysis was performed on citrated native, kaolin-activated, and tissue factor-activated blood for each sample. Two hours later, the procedure was repeated from the opposite jugular vein, yielding a total of 120 analyses. Reaction time (R), alpha angle (α), kappa value (κ), and maximum amplitude (MA) were recorded from each tracing. No significant differences were found between TEG tracings from the first and second venipuncture samples. Significant differences were found between sample types for R, α, κ, and MA. Means for citrated native/kaolin-activated/tissue factor-activated methods were R = 4.1/3.7/0.6 min; κ = 2.5/1.8/2.2 min; α = 59.9/65.1/70.4 degrees; MA = 47.4/49.9/44.7 mm. A limitation of this study was the small number of cats used. Thromboelastography analysis may be a suitable method of evaluating hemostasis in cats.

  4. Nondestructive neutron activation analysis of volcanic samples: Hawaii

    SciTech Connect

    Zoller, W.H.; Finnegan, D.L.; Crowe, B.

    1986-01-01

    Samples of volcanic emissions have been collected between and during eruptions of both Kilauea and Mauna Loa volcanoes during the last three years. Airborne particles have been collected on Teflon filters and acidic gases on base-impregnated cellulose filters. Chemically neutral gas-phase species are collected on charcoal-coated cellulose filters. The primary analytical technique used is nondestructive neutron activation analysis, which has been used to determine the quantities of up to 35 elements on the different filters. The use of neutron activation analysis makes it possible to analyze for a wide range of elements in the different matrices used for the collection and to learn about the distribution between particles and gas phases for each of the elements.

  5. Heterosexual sexual behaviour in a sample of homosexually active men.

    PubMed Central

    Fitzpatrick, R; Hart, G; Boulton, M; McLean, J; Dawson, J

    1989-01-01

    Three hundred and fifty six homosexually active men were recruited in 1988 for a study by interview of sexual behaviour. Thirty two per cent had homosexual passive anal sex in the previous month and 60% in the year before interview. Anal sex and unprotected anal sex were more common with regular than non-regular partners. Heterosexual sex was reported by 4% of men in the last month and 10% for the last year. Sixteen per cent of heterosexually active men reported anal sex with a female partner. Fewer men described themselves as bisexual than would be expected from the sample's recent sexual histories. More attention is needed to the definition and measurement of "bisexuality" to understand its role in HIV transmission. PMID:2807286

  6. Photoacoustic spectroscopy sample array vessels and photoacoustic spectroscopy methods for using the same

    DOEpatents

    Amonette, James E.; Autrey, S. Thomas; Foster-Mills, Nancy S.

    2006-02-14

    Methods and apparatus for simultaneous or sequential, rapid analysis of multiple samples by photoacoustic spectroscopy are disclosed. Particularly, a photoacoustic spectroscopy sample array vessel including a vessel body having multiple sample cells connected thereto is disclosed. At least one acoustic detector is acoustically positioned near the sample cells. Methods for analyzing the multiple samples in the sample array vessels using photoacoustic spectroscopy are provided.

  7. Seasonal Variation, Chemical Composition and Antioxidant activity of Brazilian Propolis Samples

    PubMed Central

    Teixeira, Érica Weinstein; Message, Dejair; Negri, Giuseppina; Stringheta, Paulo César

    2010-01-01

    Total phenolic contents, antioxidant activity and chemical composition of propolis samples from three localities of Minas Gerais state (southeast Brazil) were determined. Total phenolic contents were determined by the Folin–Ciocalteau method, antioxidant activity was evaluated by DPPH, using BHT as reference, and chemical composition was analyzed by GC/MS. Propolis from Itapecerica and Paula Cândido municipalities were found to have high phenolic contents and pronounced antioxidant activity. From these extracts, 40 substances were identified, among them were simple phenylpropanoids, prenylated phenylpropanoids, sesqui- and diterpenoids. Quantitatively, the main constituent of both samples was allyl-3-prenylcinnamic acid. A sample from Virginópolis municipality had no detectable phenolic substances and contained mainly triterpenoids, the main constituents being α- and β-amyrins. Methanolic extracts from Itapecerica and Paula Cândido exhibited pronounced scavenging activity towards DPPH, indistinguishable from BHT activity. However, extracts from Virginópolis sample exhibited no antioxidant activity. Total phenolic substances, GC/MS analyses and antioxidant activity of samples from Itapecerica collected monthly over a period of 1 year revealed considerable variation. No correlation was observed between antioxidant activity and either total phenolic contents or contents of artepillin C and other phenolic substances, as assayed by CG/MS analysis. PMID:18955317

  8. Seasonal variation, chemical composition and antioxidant activity of Brazilian propolis samples.

    PubMed

    Teixeira, Erica Weinstein; Message, Dejair; Negri, Giuseppina; Salatino, Antonio; Stringheta, Paulo César

    2010-09-01

    Total phenolic contents, antioxidant activity and chemical composition of propolis samples from three localities of Minas Gerais state (southeast Brazil) were determined. Total phenolic contents were determined by the Folin-Ciocalteau method, antioxidant activity was evaluated by DPPH, using BHT as reference, and chemical composition was analyzed by GC/MS. Propolis from Itapecerica and Paula Cândido municipalities were found to have high phenolic contents and pronounced antioxidant activity. From these extracts, 40 substances were identified, among them were simple phenylpropanoids, prenylated phenylpropanoids, sesqui- and diterpenoids. Quantitatively, the main constituent of both samples was allyl-3-prenylcinnamic acid. A sample from Virginópolis municipality had no detectable phenolic substances and contained mainly triterpenoids, the main constituents being α- and β-amyrins. Methanolic extracts from Itapecerica and Paula Cândido exhibited pronounced scavenging activity towards DPPH, indistinguishable from BHT activity. However, extracts from Virginópolis sample exhibited no antioxidant activity. Total phenolic substances, GC/MS analyses and antioxidant activity of samples from Itapecerica collected monthly over a period of 1 year revealed considerable variation. No correlation was observed between antioxidant activity and either total phenolic contents or contents of artepillin C and other phenolic substances, as assayed by CG/MS analysis.

  9. An automated method of sample preparation of biofluids using pierceable caps to eliminate the uncapping of the sample tubes during sample transfer.

    PubMed

    Teitz, D S; Khan, S; Powell, M L; Jemal, M

    2000-09-11

    Biological samples are normally collected and stored frozen in capped tubes until analysis. To obtain aliquots of biological samples for analysis, the sample tubes have to be thawed, uncapped, samples removed and then recapped for further storage. In this paper, we report an automated method of sample transfer devised to eliminate the uncapping and recapping process. This sampling method was incorporated into an automated liquid-liquid extraction procedure of plasma samples. Using a robotic system, the plasma samples were transferred directly from pierceable capped tubes into microtubes contained in a 96-position block. The aliquoted samples were extracted with methyl-tert-butyl ether in the same microtubes. The supernatant organic layers were transferred to a 96-well collection plate and evaporated to dryness. The dried extracts were reconstituted and injected from the same plate for analysis by liquid chromatography with tandem mass spectrometry.

  10. Validated Test Method 5030C: Purge-and-Trap for Aqueous Samples

    EPA Pesticide Factsheets

    This method describes a purge-and-trap procedure for the analysis of volatile organic compoundsin aqueous samples & water miscible liquid samples. It also describes the analysis of high concentration soil and waste sample extracts prepared in Method 5035.

  11. Evaluation of sample preservation methods for space mission

    NASA Technical Reports Server (NTRS)

    Schubert, W.; Rohatgi, N.; Kazarians, G.

    2002-01-01

    For interplanetary spacecraft that will travel to destinations where future life detection experiments may be conducted or samples are to be returned to earth, we should archive and preserve relevant samples from the spacecraft and cleanrooms for evaluation at a future date.

  12. Rapid-Viability PCR Method for Detection of Live, Virulent Bacillus anthracis in Environmental Samples

    PubMed Central

    Létant, Sonia E.; Murphy, Gloria A.; Alfaro, Teneile M.; Avila, Julie R.; Kane, Staci R.; Raber, Ellen; Bunt, Thomas M.; Shah, Sanjiv R.

    2011-01-01

    In the event of a biothreat agent release, hundreds of samples would need to be rapidly processed to characterize the extent of contamination and determine the efficacy of remediation activities. Current biological agent identification and viability determination methods are both labor- and time-intensive such that turnaround time for confirmed results is typically several days. In order to alleviate this issue, automated, high-throughput sample processing methods were developed in which real-time PCR analysis is conducted on samples before and after incubation. The method, referred to as rapid-viability (RV)-PCR, uses the change in cycle threshold after incubation to detect the presence of live organisms. In this article, we report a novel RV-PCR method for detection of live, virulent Bacillus anthracis, in which the incubation time was reduced from 14 h to 9 h, bringing the total turnaround time for results below 15 h. The method incorporates a magnetic bead-based DNA extraction and purification step prior to PCR analysis, as well as specific real-time PCR assays for the B. anthracis chromosome and pXO1 and pXO2 plasmids. A single laboratory verification of the optimized method applied to the detection of virulent B. anthracis in environmental samples was conducted and showed a detection level of 10 to 99 CFU/sample with both manual and automated RV-PCR methods in the presence of various challenges. Experiments exploring the relationship between the incubation time and the limit of detection suggest that the method could be further shortened by an additional 2 to 3 h for relatively clean samples. PMID:21764960

  13. Alternative methods for determining the electrical conductivity of core samples.

    PubMed

    Lytle, R J; Duba, A G; Willows, J L

    1979-05-01

    Electrode configurations are described that can be used in measuring the electrical conductivity of a core sample and that do not require access to the core end faces. The use of these configurations eliminates the need for machining the core ends for placement of end electrodes. This is because the conductivity in the cases described is relatively insensitive to the length of the sample. We validated the measurement technique by comparing mathematical models with actual measurements that were made perpendicular and paralled to the core axis of granite samples.

  14. Transformation-cost time-series method for analyzing irregularly sampled data.

    PubMed

    Ozken, Ibrahim; Eroglu, Deniz; Stemler, Thomas; Marwan, Norbert; Bagci, G Baris; Kurths, Jürgen

    2015-06-01

    Irregular sampling of data sets is one of the challenges often encountered in time-series analysis, since traditional methods cannot be applied and the frequently used interpolation approach can corrupt the data and bias the subsequence analysis. Here we present the TrAnsformation-Cost Time-Series (TACTS) method, which allows us to analyze irregularly sampled data sets without degenerating the quality of the data set. Instead of using interpolation we consider time-series segments and determine how close they are to each other by determining the cost needed to transform one segment into the following one. Using a limited set of operations-with associated costs-to transform the time series segments, we determine a new time series, that is our transformation-cost time series. This cost time series is regularly sampled and can be analyzed using standard methods. While our main interest is the analysis of paleoclimate data, we develop our method using numerical examples like the logistic map and the Rössler oscillator. The numerical data allows us to test the stability of our method against noise and for different irregular samplings. In addition we provide guidance on how to choose the associated costs based on the time series at hand. The usefulness of the TACTS method is demonstrated using speleothem data from the Secret Cave in Borneo that is a good proxy for paleoclimatic variability in the monsoon activity around the maritime continent.

  15. Evaluation of sampling methods for toxicological testing of indoor air particulate matter.

    PubMed

    Tirkkonen, Jenni; Täubel, Martin; Hirvonen, Maija-Riitta; Leppänen, Hanna; Lindsley, William G; Chen, Bean T; Hyvärinen, Anne; Huttunen, Kati

    2016-09-01

    There is a need for toxicity tests capable of recognizing indoor environments with compromised air quality, especially in the context of moisture damage. One of the key issues is sampling, which should both provide meaningful material for analyses and fulfill requirements imposed by practitioners using toxicity tests for health risk assessment. We aimed to evaluate different existing methods of sampling indoor particulate matter (PM) to develop a suitable sampling strategy for a toxicological assay. During three sampling campaigns in moisture-damaged and non-damaged school buildings, we evaluated one passive and three active sampling methods: the Settled Dust Box (SDB), the Button Aerosol Sampler, the Harvard Impactor and the National Institute for Occupational Safety and Health (NIOSH) Bioaerosol Cyclone Sampler. Mouse RAW264.7 macrophages were exposed to particle suspensions and cell metabolic activity (CMA), production of nitric oxide (NO) and tumor necrosis factor (TNFα) were determined after 24 h of exposure. The repeatability of the toxicological analyses was very good for all tested sampler types. Variability within the schools was found to be high especially between different classrooms in the moisture-damaged school. Passively collected settled dust and PM collected actively with the NIOSH Sampler (Stage 1) caused a clear response in exposed cells. The results suggested the higher relative immunotoxicological activity of dust from the moisture-damaged school. The NIOSH Sampler is a promising candidate for the collection of size-fractionated PM to be used in toxicity testing. The applicability of such sampling strategy in grading moisture damage severity in buildings needs to be developed further in a larger cohort of buildings.

  16. Accuracy of activPAL Self-Attachment Methods

    ERIC Educational Resources Information Center

    Kringen, Nina L.; Healy, Genevieve N.; Winkler, Elisabeth A. H.; Clark, Bronwyn K.

    2016-01-01

    This study examined the accuracy of self-attachment of the activPAL activity monitor. A convenience sample of 50 participants self-attached the monitor after being presented with written material only (WMO) and then written and video (WV) instructions; and completed a questionnaire regarding the acceptability of the instructional methods.…

  17. Analytical Chemistry Laboratory (ACL) procedure compendium. Volume 2, Sample preparation methods

    SciTech Connect

    Not Available

    1993-08-01

    This volume contains the interim change notice for sample preparation methods. Covered are: acid digestion for metals analysis, fusion of Hanford tank waste solids, water leach of sludges/soils/other solids, extraction procedure toxicity (simulate leach in landfill), sample preparation for gamma spectroscopy, acid digestion for radiochemical analysis, leach preparation of solids for free cyanide analysis, aqueous leach of solids for anion analysis, microwave digestion of glasses and slurries for ICP/MS, toxicity characteristic leaching extraction for inorganics, leach/dissolution of activated metal for radiochemical analysis, extraction of single-shell tank (SST) samples for semi-VOC analysis, preparation and cleanup of hydrocarbon- containing samples for VOC and semi-VOC analysis, receiving of waste tank samples in onsite transfer cask, receipt and inspection of SST samples, receipt and extrusion of core samples at 325A shielded facility, cleaning and shipping of waste tank samplers, homogenization of solutions/slurries/sludges, and test sample preparation for bioassay quality control program.

  18. Associations between Physical Activity and Health-Related Factors in a National Sample of College Students

    ERIC Educational Resources Information Center

    Dinger, Mary K.; Brittain, Danielle R.; Hutchinson, Susan R.

    2014-01-01

    Objective: To examine associations between meeting the current moderate to vigorous physical activity (MVPA) recommendation and health-related factors in a national sample of college students. Participants: Participants (N = 67,861) completed the National College Health Assessment II during the Fall 2008/Spring 2009 academic year. Methods:…

  19. Active sampling and decision making in Drosophila chemotaxis

    PubMed Central

    Gomez-Marin, Alex; Stephens, Greg J.; Louis, Matthieu

    2011-01-01

    The ability to respond to chemical stimuli is fundamental to the survival of motile organisms, but the strategies underlying odour tracking remain poorly understood. Here we show that chemotaxis in Drosophila melanogaster larvae is an active sampling process analogous to sniffing in vertebrates. Combining computer-vision algorithms with reconstructed olfactory environments, we establish that larvae orient in odour gradients through a sequential organization of stereotypical behaviours, including runs, stops, lateral head casts and directed turns. Negative gradients, integrated during runs, control the timing of turns. Positive gradients detected through high-amplitude head casts determine the direction of individual turns. By genetically manipulating the peripheral olfactory circuit, we examine how orientation adapts to losses and gains of function in olfactory input. Our findings suggest that larval chemotaxis represents an intermediate navigation strategy between the biased random walks of Escherichia Coli and the stereo-olfaction observed in rats and humans. PMID:21863008

  20. Comparison of sample preparation methods for the recovery of foodborne pathogens from fresh produce.

    PubMed

    Kim, Se-Ri; Yoon, Yohan; Kim, Won-Il; Park, Kyeong-Hun; Yun, Hye-Jeong; Chung, Duck Hwa; Yun, Jong Chul; Ryu, Kyoung Yul

    2012-07-01

    Sample preparation methods (pummeling, pulsifying, sonication, and shaking by hand) were compared for achieving maximum recovery of foodborne pathogens from iceberg lettuce, perilla leaves, cucumber, green pepper, and cherry tomato. Antimicrobial and dehydration effects also were examined to investigate causes of poor recovery of pathogens. Each produce type was inoculated with Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus at 6.0 log CFU/cm(2), and samples were prepared using the four methods. Bacterial populations recovered from the five types of produce were significantly different (P < 0.05) according to sample preparation methods and produce type. The bacterial populations recovered from pummeled and pulsified samples were higher (P < 0.05) than those recovered from sonicated and hand-shaken samples, except for cherry tomato. The number of bacteria recovered from produce was reduced (P < 0.05) from that of the inoculum by 0.16 to 2.69 log CFU/cm(2). Although extracts of iceberg lettuce, perilla leaves, cucumber, and green pepper had no antimicrobial activity, the populations of E. coli O157:H7, Salmonella Typhimurium, B. cereus, and L. monocytogenes in cherry tomato extract were slightly reduced after these treatments (P < 0.05). The pathogen populations on perilla leaves and cherry tomatoes decreased by >2 log CFU/cm(2) after exposure to 40% relative humidity for 1 h. No reduction was observed when the five pathogens were exposed to 90% relative humidity. These data suggest that pummeling and pulsifying are optimal sample preparation methods for detection of microorganisms. Acidic produce such as cherry tomato should be treated with a method that does not cause sample breakdown so that acid stress on the bacteria can be minimized. Dehydration stress also affects recovery of pathogens from produce.

  1. Field sampling method for quantifying odorants in humid environments.

    PubMed

    Trabue, Steven L; Scoggin, Kenwood D; Li, Hong; Burns, Robert; Xin, Hongwei

    2008-05-15

    Most air quality studies in agricultural environments use thermal desorption analysis for quantifying semivolatile organic compounds (SVOCs) associated with odor. The objective of this study was to develop a robust sampling technique for measuring SVOCs in humid environments. Test atmospheres were generated at ambient temperatures (23 +/- 1.5 degrees C) and 25, 50, and 80% relative humidity (RH). Sorbent material used included Tenax, graphitized carbon, and carbon molecular sieve (CMS). Sorbent tubes were challenged with 2, 4, 8, 12, and 24 L of air at various RHs. Sorbent tubes with CMS material performed poorly at both 50 and 80% RH dueto excessive sorption of water. Heating of CMS tubes during sampling or dry-purging of CMS tubes post sampling effectively reduced water sorption with heating of tubes being preferred due to the higher recovery and reproducibility. Tenaxtubes had breakthrough of the more volatile compounds and tended to form artifacts with increasing volumes of air sampled. Graphitized carbon sorbent tubes containing Carbopack X and Carbopack C performed best with quantitative recovery of all compounds at all RHs and sampling volumes tested. The graphitized carbon tubes were taken to the field for further testing. Field samples taken from inside swine feeding operations showed that butanoic acid, 4-methylphenol, 4-ethylphenol, indole, and 3-methylindole were the compounds detected most often above their odor threshold values. Field samples taken from a poultry facility demonstrated that butanoic acid, 3-methylbutanoic acid, and 4-methylphenol were the compounds above their odor threshold values detected most often, relative humidity, CAFO, VOC, SVOC, thermal desorption, swine, poultry, air quality, odor.

  2. Measurements of cloud condensation nuclei activity and droplet activation kinetics of wet processed regional dust samples and minerals

    NASA Astrophysics Data System (ADS)

    Kumar, P.; Sokolik, I. N.; Nenes, A.

    2011-04-01

    This study reports laboratory measurements of particle size distributions, cloud condensation nuclei (CCN) activity, and droplet activation kinetics of wet generated aerosols from clays, calcite, quartz, and desert soil samples from Northern Africa, East Asia/China, and Northern America. The dependence of critical supersaturation, sc, on particle dry diameter, Ddry, is used to characterize particle-water interactions and assess the ability of Frenkel-Halsey-Hill adsorption activation theory (FHH-AT) and Köhler theory (KT) to describe the CCN activity of the considered samples. Regional dust samples produce unimodal size distributions with particle sizes as small as 40 nm, CCN activation consistent with KT, and exhibit hygroscopicity similar to inorganic salts. Clays and minerals produce a bimodal size distribution; the CCN activity of the smaller mode is consistent with KT, while the larger mode is less hydrophilic, follows activation by FHH-AT, and displays almost identical CCN activity to dry generated dust. Ion Chromatography (IC) analysis performed on regional dust samples indicates a soluble fraction that cannot explain the CCN activity of dry or wet generated dust. A mass balance and hygroscopicity closure suggests that the small amount of ions (of low solubility compounds like calcite) present in the dry dust dissolve in the aqueous suspension during the wet generation process and give rise to the observed small hygroscopic mode. Overall these results identify an artifact that may question the atmospheric relevance of dust CCN activity studies using the wet generation method. Based on a threshold droplet growth analysis, wet generated mineral aerosols display similar activation kinetics compared to ammonium sulfate calibration aerosol. Finally, a unified CCN activity framework that accounts for concurrent effects of solute and adsorption is developed to describe the CCN activity of aged or hygroscopic dusts.

  3. Photoacoustic spectroscopy sample array vessel and photoacoustic spectroscopy method for using the same

    DOEpatents

    Amonette, James E.; Autrey, S. Thomas; Foster-Mills, Nancy S.; Green, David

    2005-03-29

    Methods and apparatus for analysis of multiple samples by photoacoustic spectroscopy are disclosed. Particularly, a photoacoustic spectroscopy sample array vessel including a vessel body having multiple sample cells connected thereto is disclosed. At least one acoustic detector is acoustically coupled with the vessel body. Methods for analyzing the multiple samples in the sample array vessels using photoacoustic spectroscopy are provided.

  4. Analytical instrument with apparatus and method for sample concentrating

    DOEpatents

    Zaromb, S.

    1986-08-04

    A system for analysis of trace concentrations of contaminants in air includes a portable liquid chromatograph and a preconcentrator for the contaminants to be analyzed. The preconcentrator includes a sample bag having an inlet valve and an outlet valve for collecting an air sample. When the sample is collected the sample bag is connected in series with a sorbing apparatus in a recirculation loop. The sorbing apparatus has an inner gas-permeable container containing a sorbent material and an outer gas-impermeable container. The sample is circulated through the outer container and around the inner container for trapping and preconcentrating the contaminants in the sorbent material. The sorbent material may be a liquid having the same composition as the mobile phase of the chromatograph for direct injection thereinto. Alternatively, the sorbent material may be a porous, solid body, to which mobile phase liquid is added after preconcentration of the contaminants for dissolving the contaminants, the liquid solution then being withdrawn for injection into the chromatograph.

  5. Method for preconcentrating a sample for subsequent analysis

    DOEpatents

    Zaromb, Solomon

    1990-01-01

    A system for analysis of trace concentration of contaminants in air includes a portable liquid chromatograph and a preconcentrator for the contaminants to be analyzed. The preconcentrator includes a sample bag having an inlet valve and an outlet valve for collecting an air sample. When the sample is collected the sample bag is connected in series with a sorbing apparatus in a recirculation loop. The sorbing apparatus has an inner gas-permeable container containing a sorbent material and an outer gas-impermeable container. The sample is circulated through the outer container and around the inner container for trapping and preconcentrating the contaminants in the sorbent material. The sorbent material may be a liquid having the same composition as the mobile phase of the chromatograph for direct injection thereinto. Alternatively, the sorbent material may be a porous, solid body, to which mobile phase liquid is added after preconcentration of the contaminants for dissolving the contaminants, the liquid solution then being withdrawn for injection into the chromatograph.

  6. Sample Selection in Randomized Experiments: A New Method Using Propensity Score Stratified Sampling

    ERIC Educational Resources Information Center

    Tipton, Elizabeth; Hedges, Larry; Vaden-Kiernan, Michael; Borman, Geoffrey; Sullivan, Kate; Caverly, Sarah

    2014-01-01

    Randomized experiments are often seen as the "gold standard" for causal research. Despite the fact that experiments use random assignment to treatment conditions, units are seldom selected into the experiment using probability sampling. Very little research on experimental design has focused on how to make generalizations to well-defined…

  7. Statistical Methods and Tools for Hanford Staged Feed Tank Sampling

    SciTech Connect

    Fountain, Matthew S.; Brigantic, Robert T.; Peterson, Reid A.

    2013-10-01

    This report summarizes work conducted by Pacific Northwest National Laboratory to technically evaluate the current approach to staged feed sampling of high-level waste (HLW) sludge to meet waste acceptance criteria (WAC) for transfer from tank farms to the Hanford Waste Treatment and Immobilization Plant (WTP). The current sampling and analysis approach is detailed in the document titled Initial Data Quality Objectives for WTP Feed Acceptance Criteria, 24590-WTP-RPT-MGT-11-014, Revision 0 (Arakali et al. 2011). The goal of this current work is to evaluate and provide recommendations to support a defensible, technical and statistical basis for the staged feed sampling approach that meets WAC data quality objectives (DQOs).

  8. Implementation of Fowler's method for end-tidal air sampling.

    PubMed

    Di Francesco, F; Loccioni, C; Fioravanti, M; Russo, A; Pioggia, G; Ferro, M; Roehrer, I; Tabucchi, S; Onor, M

    2008-09-01

    The design, realization and testing of a CO(2)-triggered breath sampler, capable of a separate collection of dead space and end-tidal air on multiple breaths, is presented. This sampling procedure has advantages in terms of the sample volume, insights regarding the origin of compounds, increased reproducibility and higher concentrations of compounds. The high quality of design and the speed of the components ensure a breath-by-breath estimate of dead volume, as well as the comfort and safety of the subject under test. The system represents a valid tool to contribute to the development of a standardized sampling protocol needed to compare results obtained by the various groups in this field.

  9. Apparatus and method for centrifugation and robotic manipulation of samples

    NASA Technical Reports Server (NTRS)

    Vellinger, John C. (Inventor); Ormsby, Rachel A. (Inventor); Kennedy, David J. (Inventor); Thomas, Nathan A. (Inventor); Shulthise, Leo A. (Inventor); Kurk, Michael A. (Inventor); Metz, George W. (Inventor)

    2007-01-01

    A device for centrifugation and robotic manipulation of specimen samples, including incubating eggs, and uses thereof are provided. The device may advantageously be used for the incubation of avian, reptilian or any type of vertebrate eggs. The apparatus comprises a mechanism for holding samples individually, rotating them individually, rotating them on a centrifuge collectively, injecting them individually with a fixative or other chemical reagent, and maintaining them at controlled temperature, relative humidity and atmospheric composition. The device is applicable to experiments involving entities other than eggs, such as invertebrate specimens, plants, microorganisms and molecular systems.

  10. Activation energy for a model ferrous-ferric half reaction from transition path sampling

    NASA Astrophysics Data System (ADS)

    Drechsel-Grau, Christof; Sprik, Michiel

    2012-01-01

    Activation parameters for the model oxidation half reaction of the classical aqueous ferrous ion are compared for different molecular simulation techniques. In particular, activation free energies are obtained from umbrella integration and Marcus theory based thermodynamic integration, which rely on the diabatic gap as the reaction coordinate. The latter method also assumes linear response, and both methods obtain the activation entropy and the activation energy from the temperature dependence of the activation free energy. In contrast, transition path sampling does not require knowledge of the reaction coordinate and directly yields the activation energy [C. Dellago and P. G. Bolhuis, Mol. Simul. 30, 795 (2004), 10.1080/08927020412331294869]. Benchmark activation energies from transition path sampling agree within statistical uncertainty with activation energies obtained from standard techniques requiring knowledge of the reaction coordinate. In addition, it is found that the activation energy for this model system is significantly smaller than the activation free energy for the Marcus model, approximately half the value, implying an equally large entropy contribution.

  11. Effects of repeated blood samplings on locomotor activity, evasion and wheel-running activity in mice.

    PubMed

    Pfeil, R

    1988-01-01

    The effects of serial blood sampling on nocturnal locomotor activity, evasion, wheel-running activity and body mass were studied in male NMRI mice aged 7-8 weeks. The erythrocyte count, haematocrit and haemoglobin concentration at the beginning and end of the study showed no difference in group 1 (two samples per week, 0.08 ml each) while there was a significant decrease in the group 2 values (three samples per week, 0.08 ml each). The total amount of nocturnal locomotor activity decreased in the animals bled repeatedly while the periods with locomotor activity increased. These alterations appeared particularly after bleeding. In the test-group animals evasion showed a decrease compared with the untreated control animals, but there was no evidence of a relation to the timing of the bleedings.

  12. A calorimetric method to determine water activity

    NASA Astrophysics Data System (ADS)

    Björklund, Sebastian; Wadsö, Lars

    2011-11-01

    A calorimetric method to determine water activity covering the full range of the water activity scale is presented. A dry stream of nitrogen gas is passed either over the solution whose activity should be determined or left dry before it is saturated by bubbling through water in an isothermal calorimeter. The unknown activity is in principle determined by comparing the thermal power of vaporization related to the gas stream with unknown activity to that with zero activity. Except for three minor corrections (for pressure drop, non-perfect humidification, and evaporative cooling) the unknown water activity is calculated solely based on the water activity end-points zero and unity. Thus, there is no need for calibration with references with known water activities. The method has been evaluated at 30 °C by measuring the water activity of seven aqueous sodium chloride solutions ranging from 0.1 mol kg-1 to 3 mol kg-1 and seven saturated aqueous salt solutions (LiCl, MgCl2, NaBr, NaCl, KCl, KNO3, and K2SO4) with known water activities. The performance of the method was adequate over the complete water activity scale. At high water activities the performance was excellent, which is encouraging as many other methods used for water activity determination have limited performance at high water activities.

  13. SAMSAN- MODERN NUMERICAL METHODS FOR CLASSICAL SAMPLED SYSTEM ANALYSIS

    NASA Technical Reports Server (NTRS)

    Frisch, H. P.

    1994-01-01

    SAMSAN was developed to aid the control system analyst by providing a self consistent set of computer algorithms that support large order control system design and evaluation studies, with an emphasis placed on sampled system analysis. Control system analysts have access to a vast array of published algorithms to solve an equally large spectrum of controls related computational problems. The analyst usually spends considerable time and effort bringing these published algorithms to an integrated operational status and often finds them less general than desired. SAMSAN reduces the burden on the analyst by providing a set of algorithms that have been well tested and documented, and that can be readily integrated for solving control system problems. Algorithm selection for SAMSAN has been biased toward numerical accuracy for large order systems with computational speed and portability being considered important but not paramount. In addition to containing relevant subroutines from EISPAK for eigen-analysis and from LINPAK for the solution of linear systems and related problems, SAMSAN contains the following not so generally available capabilities: 1) Reduction of a real non-symmetric matrix to block diagonal form via a real similarity transformation matrix which is well conditioned with respect to inversion, 2) Solution of the generalized eigenvalue problem with balancing and grading, 3) Computation of all zeros of the determinant of a matrix of polynomials, 4) Matrix exponentiation and the evaluation of integrals involving the matrix exponential, with option to first block diagonalize, 5) Root locus and frequency response for single variable transfer functions in the S, Z, and W domains, 6) Several methods of computing zeros for linear systems, and 7) The ability to generate documentation "on demand". All matrix operations in the SAMSAN algorithms assume non-symmetric matrices with real double precision elements. There is no fixed size limit on any matrix in any

  14. A Bayesian Method to Improve Sampling in Weapons Testing

    DTIC Science & Technology

    1988-12-01

    New York, 1961. 4. Duncan, Acheson J., Quality Control and Industrial Statistics, Richard D. Irwan, Inc., Homewood, Illinois, 1986. 5. DeGroot ... Morris H., Probability and Statistics, Second Edition, Addison-Wesley Publishing Company, Inc., USA, 1986. 6. Manion, Rober B., Number of Samples Needed

  15. Improved sample management in the cylindrical-tube microelectrophoresis method

    NASA Technical Reports Server (NTRS)

    Smolka, A. J. K.

    1980-01-01

    A modification to an analytical microelectrophoresis system is described that improves the manipulation of the sample particles and fluid. The apparatus modification and improved operational procedure should yield more accurate measurements of particle mobilities and permit less skilled operators to use the apparatus.

  16. A rapid wire-based sampling method for DNA profiling.

    PubMed

    Chen, Tong; Catcheside, David E A; Stephenson, Alice; Hefford, Chris; Kirkbride, K Paul; Burgoyne, Leigh A

    2012-03-01

    This paper reports the results of a commission to develop a field deployable rapid short tandem repeat (STR)-based DNA profiling system to enable discrimination between tissues derived from a small number of individuals. Speed was achieved by truncation of sample preparation and field deployability by use of an Agilent 2100 Bioanalyser(TM). Human blood and tissues were stabbed with heated stainless steel wire and the resulting sample dehydrated with isopropanol prior to direct addition to a PCR. Choice of a polymerase tolerant of tissue residues and cycles of amplification appropriate for the amount of template expected yielded useful profiles with a custom-designed quintuplex primer set suitable for use with the Bioanalyser(TM). Samples stored on wires remained amplifiable for months, allowing their transportation unrefrigerated from remote locations to a laboratory for analysis using AmpFlSTR(®) Profiler Plus(®) without further processing. The field system meets the requirements for discrimination of samples from small sets and retains access to full STR profiling when required.

  17. Technical Evaluation of Sample-Processing, Collection, and Preservation Methods

    DTIC Science & Technology

    2014-07-01

    policy document entitled The National Strategy for Biosurveillance was released (White House, July 2012) as part of the National Security Strategy...concept of leveraging existing capabilities to “scan and discern the environment,” which implies the use of current technical biosurveillance ...testing of existing sample-processing technologies are expected to enable in silico evaluations of biosurveillance methodologies, equipment, and

  18. Modern Numerical Methods for Classical Sampled System Analysis-SAMSAN

    NASA Technical Reports Server (NTRS)

    Frisch, H. P.

    1984-01-01

    SAMSAN aids control-system analyst by providing self-consistent set of computer algorithms that support large-order control-system design and evaluation studies, with emphasis placed on sampled system analysis. Program provides set of algorithms readily integrated for solving control-system problems.

  19. Numerical Methods for Classical Sampled-System Analysis

    NASA Technical Reports Server (NTRS)

    Frisch, H. P.; Bauer, F. H.

    1986-01-01

    SAMSAN provides control-system analyst with self-consistent computer algorithms that support large-order control-system design and evaluation studies. Emphasizes sampled-system analysis. SAMSAN reduces burden on analyst by providing set of algorithms well tested and documented and readily integrated for solving control-system problems.

  20. Rapid and reliable determination of the halogenating peroxidase activity in blood samples.

    PubMed

    Flemmig, Jörg; Schwarz, Pauline; Bäcker, Ingo; Leichsenring, Anna; Lange, Franziska; Arnhold, Jürgen

    2014-12-15

    By combining easy and fast leukocyte enrichment with aminophenyl-fluorescein (APF) staining we developed a method to quickly and specifically address the halogenating activity of the immunological relevant blood heme peroxidases myeloperoxidase and eosinophil peroxidase, respectively. For leukocyte enrichment a two-fold hypotonic lysis procedure of the blood with Millipore water was chosen which represents a cheap, fast and reliable method to diminish the amount of erythrocytes in the samples. This procedure is shown to be suitable both to human and murine blood micro-samples, making it also applicable to small animal experiments with recurring blood sampling. As all types of leukocytes are kept in the sample during the preparation, they can be analysed separately after discrimination during the flow cytometry analysis. This also holds for all heme peroxidase-containing cells, namely neutrophils, eosinophils and monocytes. Moreover additional parameters (e.g. antibody staining) can be combined with the heme peroxidase activity determination to gain additional information about the different immune cell types. Based on previous results we applied APF for specifically addressing the halogenating activity of leukocyte peroxidases in blood samples. This dye is selectively oxidized by the MPO and EPO halogenation products hypochlorous and hypobromous acid. This approach may provide a suitable tool to gain more insights into the immune-physiological role of the halogenating activity of heme peroxidases.

  1. The laboratory methods of induced polarization measurement of manganese sample

    NASA Astrophysics Data System (ADS)

    Adhiguna, D.; Handayani, G.

    2015-09-01

    Metallic minerals are polarizable. The polarizable property can be used as the basis for metallic minerals exploration process. By use of induced polarization method, we observed polarization phenomenon that occur in metallic material. In this study, physical events were observed that occur in rocks containing manganese minerals using induced polarization method. Induced polarization method is a geophysical method that is based on the principle of electrical charging and discharging of a capacitor which is applied to the rock. By using the method of induced polarization, chargeability values can be determined for the rock. Chargeability is one of the important properties of metal material. Measurement on this research will be done in two different ways to determine the induced events that occurred in both methods.

  2. Post-Decontamination Vapor Sampling and Analytical Test Methods

    DTIC Science & Technology

    2015-08-12

    emission rate) after treatment with a decontamination system (decontaminant and/or applicator) used against CWAs, simulants, NTAs, TICs, or other...Residual liquid testing is addressed in TOP 08-2-061A1*. b. This TOP includes procedures for analyzing the decontamination of equipment and...Residual contaminant in samples from solid sorbent tubes (SSTs), or equivalent. Gas chromatograph (GC), liquid chromatograph (LC), flame

  3. INVESTIGATION OF THE TOTAL ORGANIC HALOGEN ANALYTICAL METHOD AT THE WASTE SAMPLING AND CHARACTERIZATION FACILITY

    SciTech Connect

    JG DOUGLAS; HK MEZNARICH, PHD; JR OLSEN; GA ROSS PHD; M STAUFFER

    2009-02-13

    Total organic halogen (TOX) is used as a parameter to screen groundwater samples at the Hanford Site. Trending is done for each groundwater well, and changes in TOX and other screening parameters can lead to costly changes in the monitoring protocol. The Waste Sampling and Characterization Facility (WSCF) analyzes groundwater samples for TOX using the United States Environmental Protection Agency (EPA) SW-S46 method 9020B (EPA 1996a). Samples from the Soil and Groundwater Remediation Project (SGRP) are submitted to the WSCF for analysis without information regarding the source of the sample; each sample is in essence a ''blind'' sample to the laboratory. Feedback from the SGRP indicated that some of the WSCF-generated TOX data from groundwater wells had a number of outlier values based on the historical trends (Anastos 200Sa). Additionally, analysts at WSCF observed inconsistent TOX results among field sample replicates. Therefore, the WSCF lab performed an investigation of the TOX analysis to determine the cause of the outlier data points. Two causes were found that contributed to generating out-of-trend TOX data: (1) The presence of inorganic chloride in the groundwater samples: at inorganic chloride concentrations greater than about 10 parts per million (ppm), apparent TOX values increase with increasing chloride concentration. A parallel observation is the increase in apparent breakthrough of TOX from the first to the second activated-carbon adsorption tubes with increasing inorganic chloride concentration. (2) During the sample preparation step, excessive purging of the adsorption tubes with oxygen pressurization gas after sample loading may cause channeling in the activated carbon bed. This channeling leads to poor removal of inorganic chloride during the subsequent wash step with aqueous potassium nitrate. The presence of this residual inorganic chloride then produces erroneously high TOX values. Changes in sample preparation were studied to more effectively

  4. A new method of snowmelt sampling for water stable isotopes

    USGS Publications Warehouse

    Penna, D.; Ahmad, M.; Birks, S. J.; Bouchaou, L.; Brencic, M.; Butt, S.; Holko, L.; Jeelani, G.; Martinez, D. E.; Melikadze, G.; Shanley, J.B.; Sokratov, S. A.; Stadnyk, T.; Sugimoto, A.; Vreca, P.

    2014-01-01

    We modified a passive capillary sampler (PCS) to collect snowmelt water for isotopic analysis. Past applications of PCSs have been to sample soil water, but the novel aspect of this study was the placement of the PCSs at the ground-snowpack interface to collect snowmelt. We deployed arrays of PCSs at 11 sites in ten partner countries on five continents representing a range of climate and snow cover worldwide. The PCS reliably collected snowmelt at all sites and caused negligible evaporative fractionation effects in the samples. PCS is low-cost, easy to install, and collects a representative integrated snowmelt sample throughout the melt season or at the melt event scale. Unlike snow cores, the PCS collects the water that would actually infiltrate the soil; thus, its isotopic composition is appropriate to use for tracing snowmelt water through the hydrologic cycle. The purpose of this Briefing is to show the potential advantages of PCSs and recommend guidelines for constructing and installing them based on our preliminary results from two snowmelt seasons.

  5. Capture-recapture and removal methods for sampling closed populations

    USGS Publications Warehouse

    White, Gary C.; Anderson, David R.; Burnham, Kenneth P.; Otis, David L.

    1982-01-01

    The problem of estimating animal abundance is common in wildlife management and environmental impact asessment. Capture-recapture and removal methods are often used to estimate population size. Statistical Inference From Capture Data On Closed Animal Populations, a monograph by Otis et al. (1978), provides a comprehensive synthesis of much of the wildlife and statistical literature on the methods, as well as some extensions of the general theory. In our primer, we focus on capture-recapture and removal methods for trapping studies in which a population is assumed to be closed and do not treat open-population models, such as the Jolly-Seber model, or catch-effort methods in any detail. The primer, written for students interested in population estimation, is intended for use with the more theoretical monograph.

  6. Detecting spatial structures in throughfall data: the effect of extent, sample size, sampling design, and variogram estimation method

    NASA Astrophysics Data System (ADS)

    Voss, Sebastian; Zimmermann, Beate; Zimmermann, Alexander

    2016-04-01

    In the last three decades, an increasing number of studies analyzed spatial patterns in throughfall to investigate the consequences of rainfall redistribution for biogeochemical and hydrological processes in forests. In the majority of cases, variograms were used to characterize the spatial properties of the throughfall data. The estimation of the variogram from sample data requires an appropriate sampling scheme: most importantly, a large sample and an appropriate layout of sampling locations that often has to serve both variogram estimation and geostatistical prediction. While some recommendations on these aspects exist, they focus on Gaussian data and high ratios of the variogram range to the extent of the study area. However, many hydrological data, and throughfall data in particular, do not follow a Gaussian distribution. In this study, we examined the effect of extent, sample size, sampling design, and calculation methods on variogram estimation of throughfall data. For our investigation, we first generated non-Gaussian random fields based on throughfall data with heavy outliers. Subsequently, we sampled the fields with three extents (plots with edge lengths of 25 m, 50 m, and 100 m), four common sampling designs (two grid-based layouts, transect and random sampling), and five sample sizes (50, 100, 150, 200, 400). We then estimated the variogram parameters by method-of-moments and residual maximum likelihood. Our key findings are threefold. First, the choice of the extent has a substantial influence on the estimation of the variogram. A comparatively small ratio of the extent to the correlation length is beneficial for variogram estimation. Second, a combination of a minimum sample size of 150, a design that ensures the sampling of small distances and variogram estimation by residual maximum likelihood offers a good compromise between accuracy and efficiency. Third, studies relying on method-of-moments based variogram estimation may have to employ at least

  7. Detecting spatial structures in throughfall data: The effect of extent, sample size, sampling design, and variogram estimation method

    NASA Astrophysics Data System (ADS)

    Voss, Sebastian; Zimmermann, Beate; Zimmermann, Alexander

    2016-09-01

    In the last decades, an increasing number of studies analyzed spatial patterns in throughfall by means of variograms. The estimation of the variogram from sample data requires an appropriate sampling scheme: most importantly, a large sample and a layout of sampling locations that often has to serve both variogram estimation and geostatistical prediction. While some recommendations on these aspects exist, they focus on Gaussian data and high ratios of the variogram range to the extent of the study area. However, many hydrological data, and throughfall data in particular, do not follow a Gaussian distribution. In this study, we examined the effect of extent, sample size, sampling design, and calculation method on variogram estimation of throughfall data. For our investigation, we first generated non-Gaussian random fields based on throughfall data with large outliers. Subsequently, we sampled the fields with three extents (plots with edge lengths of 25 m, 50 m, and 100 m), four common sampling designs (two grid-based layouts, transect and random sampling) and five sample sizes (50, 100, 150, 200, 400). We then estimated the variogram parameters by method-of-moments (non-robust and robust estimators) and residual maximum likelihood. Our key findings are threefold. First, the choice of the extent has a substantial influence on the estimation of the variogram. A comparatively small ratio of the extent to the correlation length is beneficial for variogram estimation. Second, a combination of a minimum sample size of 150, a design that ensures the sampling of small distances and variogram estimation by residual maximum likelihood offers a good compromise between accuracy and efficiency. Third, studies relying on method-of-moments based variogram estimation may have to employ at least 200 sampling points for reliable variogram estimates. These suggested sample sizes exceed the number recommended by studies dealing with Gaussian data by up to 100 %. Given that most previous

  8. A method for simultaneous determination of 210Pb and 212Pb in drinking water samples

    NASA Astrophysics Data System (ADS)

    Jia, Guogang; Torri, G.; Leandro, M.

    2012-04-01

    A sensitive and accurate method for determination of 210Pb and 212Pb in drinking water samples was developed. In the method Pb was pre-concentrated as hydroxides, separated from alkaline earth elements as PbS precipitate, purified by an anion exchange resin chro-matography column, precipitated as PbSC4 for source preparation and counted by a low background β-counter. The procedure was checked with a reference material supplied by the IAEA, and the obtained data were in good agreement with the recommended values, showing the recommended procedure can provide reliable results. The minimum detectable activity of the method was 0.039 mBq L-1 for 210Pb and 0.033 mBq L-1 for 212Pb if a 48 liter of water sample was analyzed. Seventeen drinking water samples were analyzed with a Pb recovery of 88.8 ± 5.5%, and the typical activity concentration was in the range of 0.191-15.1 mBq L-1 for 210Pb and of 1.12-5.77 mBq L-1 for 212Pb.

  9. Analytical methods for the determination of personal care products in human samples: an overview.

    PubMed

    Jiménez-Díaz, I; Zafra-Gómez, A; Ballesteros, O; Navalón, A

    2014-11-01

    Personal care products (PCPs) are organic chemicals widely used in everyday human life. Nowadays, preservatives, UV-filters, antimicrobials and musk fragrances are widely used PCPs. Different studies have shown that some of these compounds can cause adverse health effects, such as genotoxicity, which could even lead to mutagenic or carcinogenic effects, or estrogenicity because of their endocrine disruption activity. Due to the absence of official monitoring protocols, there is an increasing demand of analytical methods that allow the determination of those compounds in human samples in order to obtain more information regarding their behavior and fate in the human body. The complexity of the biological matrices and the low concentration levels of these compounds make necessary the use of advanced sample treatment procedures that afford both, sample clean-up, to remove potentially interfering matrix components, as well as the concentration of analytes. In the present work, a review of the more recent analytical methods published in the scientific literature for the determination of PCPs in human fluids and tissue samples, is presented. The work focused on sample preparation and the analytical techniques employed.

  10. A personal sampling method for the determination of styrene exposure.

    PubMed

    Brown, R H; Saunders, K J; Walkin, K T

    1987-09-01

    A diffusive sampler, which is suitable for the determination of time-weighted average personal and static exposures to styrene, is described. The sampler is based on a commercially available tube design that is amenable to fully-automated thermal desorption. The performance of the sampler has been evaluated using a protocol, developed by the U.K. Health and Safety Executive, involving both laboratory and field experiments. The sampler has been shown to give results that are similar both in magnitude and precision to those obtained using conventional sorbent tube and pump methods. The diffusive method is preferred because of its simplicity and convenience.

  11. 7 CFR 31.400 - Samples for wool and wool top grades; method of obtaining.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Samples for wool and wool top grades; method of... STANDARDS AND STANDARD CONTAINER REGULATIONS PURCHASE OF WOOL AND WOOL TOP SAMPLES § 31.400 Samples for wool and wool top grades; method of obtaining. Samples certified as representative of the...

  12. 7 CFR 31.400 - Samples for wool and wool top grades; method of obtaining.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Samples for wool and wool top grades; method of... STANDARDS AND STANDARD CONTAINER REGULATIONS PURCHASE OF WOOL AND WOOL TOP SAMPLES § 31.400 Samples for wool and wool top grades; method of obtaining. Samples certified as representative of the...

  13. 7 CFR 32.402 - Samples of mohair top grades; method of obtaining.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Samples of mohair top grades; method of obtaining. 32... STANDARD CONTAINER REGULATIONS PURCHASE OF GREASE MOHAIR AND MOHAIR TOP SAMPLES § 32.402 Samples of mohair top grades; method of obtaining. Samples certified as representative of the official standards of...

  14. Rapid method to determine 89Sr/90Sr in large concrete samples

    DOE PAGES

    Maxwell, Sherrod L.; Culligan, Brian; Hutchison, Jay B.; ...

    2016-03-24

    Here, a new rapid method has been developed that provides high quality low-level measurements of 89,90Sr in concrete samples with an MDA (Minimum Detectable Activity) of <1 mBq g-1. The new method is fast, meets new decommissioning regulatory limits and is robust even if refractory particles are present. The method utilizes a rapid fusion to ensure total dissolution of samples and rapid preconcentration and separation of 89,90Sr from 5-10 g concrete samples. When, the 89Sr/90Sr ratio is high, Sr can be isolated from up to 5g concrete samples, total 89/90Sr measured, and then 90Sr determined via 90Y separated after amore » period of ingrowth. Another approach allows the immediate determination of 90Sr in 10 g concrete aliquots without waiting for 90Y ingrowth, in instances where the shorter lived 89Sr is unlikely to be encountered.« less

  15. TESTING METHODS FOR DETECTION OF CRYPTOSPORIDIUM SPP. IN WATER SAMPLES

    EPA Science Inventory

    A large waterborne outbreak of cryptosporidiosis in Milwaukee, Wisconsin, U.S.A. in 1993 prompted a search for ways to prevent large-scale waterborne outbreaks of protozoan parasitoses. Methods for detecting Cryptosporidium parvum play an integral role in strategies that lead to...

  16. Ant colony optimization as a method for strategic genotype sampling.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A simulation study was carried out to develop an alternative method of selecting animals to be genotyped. Simulated pedigrees included 5000 animals, each assigned genotypes for a bi-allelic single nucleotide polymorphism (SNP) based on assumed allelic frequencies of 0.7/ 0.3 and 0.5/0.5. In addition...

  17. COMPARISON OF LARGE RIVER SAMPLING METHOD USING DIATOM METRICS

    EPA Science Inventory

    We compared the results of four methods used to assess the algal communities at 60 sites distributed among four rivers. Based on Principle Component Analysis of physical habitat data collected concomitantly with the algal data, sites were separated into those with a mean thalweg...

  18. COMPARISON OF LARGE RIVER SAMPLING METHODS ON ALGAL METRICS

    EPA Science Inventory

    We compared the results of four methods used to assess the algal communities at 60 sites distributed among four rivers. Based on Principle Component Analysis of physical habitat data collected concomitantly with the algal data, sites were separated into those with a mean thalweg...

  19. 40 CFR 761.243 - Standard wipe sample method and size.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., AND USE PROHIBITIONS Determining a PCB Concentration for Purposes of Abandonment or Disposal of Natural Gas Pipeline: Selecting Sample Sites, Collecting Surface Samples, and Analyzing Standard PCB Wipe Samples § 761.243 Standard wipe sample method and size. (a) Collect a surface sample from a natural...

  20. 40 CFR 761.243 - Standard wipe sample method and size.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., AND USE PROHIBITIONS Determining a PCB Concentration for Purposes of Abandonment or Disposal of Natural Gas Pipeline: Selecting Sample Sites, Collecting Surface Samples, and Analyzing Standard PCB Wipe Samples § 761.243 Standard wipe sample method and size. (a) Collect a surface sample from a natural...

  1. 40 CFR 761.243 - Standard wipe sample method and size.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., AND USE PROHIBITIONS Determining a PCB Concentration for Purposes of Abandonment or Disposal of Natural Gas Pipeline: Selecting Sample Sites, Collecting Surface Samples, and Analyzing Standard PCB Wipe Samples § 761.243 Standard wipe sample method and size. (a) Collect a surface sample from a natural...

  2. Estimating the Expected Value of Sample Information Using the Probabilistic Sensitivity Analysis Sample: A Fast, Nonparametric Regression-Based Method.

    PubMed

    Strong, Mark; Oakley, Jeremy E; Brennan, Alan; Breeze, Penny

    2015-07-01

    Health economic decision-analytic models are used to estimate the expected net benefits of competing decision options. The true values of the input parameters of such models are rarely known with certainty, and it is often useful to quantify the value to the decision maker of reducing uncertainty through collecting new data. In the context of a particular decision problem, the value of a proposed research design can be quantified by its expected value of sample information (EVSI). EVSI is commonly estimated via a 2-level Monte Carlo procedure in which plausible data sets are generated in an outer loop, and then, conditional on these, the parameters of the decision model are updated via Bayes rule and sampled in an inner loop. At each iteration of the inner loop, the decision model is evaluated. This is computationally demanding and may be difficult if the posterior distribution of the model parameters conditional on sampled data is hard to sample from. We describe a fast nonparametric regression-based method for estimating per-patient EVSI that requires only the probabilistic sensitivity analysis sample (i.e., the set of samples drawn from the joint distribution of the parameters and the corresponding net benefits). The method avoids the need to sample from the posterior distributions of the parameters and avoids the need to rerun the model. The only requirement is that sample data sets can be generated. The method is applicable with a model of any complexity and with any specification of model parameter distribution. We demonstrate in a case study the superior efficiency of the regression method over the 2-level Monte Carlo method.

  3. [Diabetic nephropathy and plasminogen activator inhibitor 1 in urine samples].

    PubMed

    Torii, Kunio; Kimura, Hideki; Li, Xuan; Okada, Toshiharu; Imura, Toshio; Oida, Koji; Miyamori, Isamu; Furusaki, Fumio; Ono, Tomoko; Yoshida, Haruyoshi

    2004-06-01

    Plasminogen activator inhibitor-1 (PAI-1) may contribute to renal fibrosis because of its involvement in matrix (ECM) accumulation through inhibition of plasmin-dependent ECM degradation. The aim of this study is to determine urinary PAI-1 concentrations and its intrarenal localization in patients with various renal diseases and to identify inducers for PAI-1 expression in human cultured proximal renal tubular cells (HRCs). Urinary PAI-1 concentrations were significantly higher in patients with overt diabetic nephropathy (DN, n=36) than in proliferative glomerulonephritis (PGN, n=8), nephrotic syndrome (NS, n=10) and healthy controls (n=12). Urinary PAI-1 concentrations (ng/gCr) were directly correlated with urinary N-acetyl glucosaminidase (NAG) levels (r=0.58, p<0.05). As for intrarenal localization of PAI-1 antigen, strong stainings for PAI-1 were observed in proximal tubular cells of renal biopsy samples from patients with DN, while no stainings for PAI-1 were found in renal tissues of PGN or NS. Immunoblot analysis revealed the presence of PAI-1 protein in whole cell lyzates from HRCs grown to semiconfluency. Exposure of growth-arrested HRCs with hypoxia (1% O2) or TNF-alpha (10 ng/ml) for 24 hours increased the secretion rate of PAI-1 protein by about 2.0-fold, while 24-hour treatment with high glucose (450 mg/dl) did not increase PAI-1 secretion at all, compared with that of the control cells under normal glucose (100 mg/dl) and normoxia (18% O2). These findings suggest that PAI-1 expression is upregulated especially in the proximal renal tubular cells of DN, which may be explained partially by hypoxia and inflammatory cytokines but not high glucose.

  4. Development of a sampling and analysis method for 4-vinyl-1-cyclohexene in air.

    PubMed

    Kongtip, Pornpimol; Tangprakorn, Bantoon; Yoosook, Witaya; Chantanakul, Suttinun

    2008-01-01

    The purpose of this research was to develop an applicable sampling and analytical method to determine airborne 4-vinyl-1-cyclohexene concentrations which are usually found in the atmosphere of polybutadiene factories. A solid sorbent tube, containing two sections (100 mg in the front and 50 mg in the back) of activated coconut-shell charcoal was chosen for sampling 4-vinyl-1-cyclohexene vapor. The 4-vinyl-1-cyclohexene in the charcoal samples was desorbed with carbon disulfide and analyzed by gas chromatography equipped with a flame ionization detector. The suitable air flow rate, adsorption capacity, sample storage stability, desorption efficiency and reliability of the method for sampling and analysis of 4-vinyl-1-cyclohexene were evaluated. The method was applied to sampling and analysis of 4-vinyl-1-cyclohexene in the rubber industry. The results indicated a suitable air flow rate of 0.3 to 1.5 l/min. The adsorption capacity of 4-vinyl-1-cyclohexene on 100 mg of charcoal was 0.2134 mg. The 4-vinyl-1-cyclohexene adsorbed on the charcoal was stable for 7 d at room temperature or 21 d in a refrigerated condition. The average percent desorption efficiency of 4-vinyl-1-cyclohexene ranged from 90.45% to 97.04% with the loaded amount ranging from 0.412 to 8.250 microg using 1 ml carbon disulfide. The limit of detection of 4-vinyl-1-cyclohexene was 0.044 ng. The average percent recoveries (n=6) of 4-vinyl-1-cyclohexene adsorbed on charcoal ranging from 0.46 to 8.87 microg were 96.78-102.87% with relative standard deviations (RSDs) of 0.34-1.92%, respectively. The concentrations of 4-vinyl-1-cyclohexene ranged from 0.011 to 0.105 mg/m(3) in the working environment of a polybutadiene factory.

  5. A sampling method for conducting relocation studies with freshwater mussels

    USGS Publications Warehouse

    Waller, D.L.; Rach, J.J.; Cope, W.G.; Luoma, J.A.

    1993-01-01

    Low recovery of transplanted mussels often prevents accurate estimates of survival. We developed a method that provided a high recovery of transplanted mussels and allowed for a reliable assessment of mortality. A 3 x 3 m polyvinyl chloride (PVC) pipe grid was secured to the sediment with iron reinforcing bars. The grid was divided into nine 1-m super(2) segments and each treatment segment, was stocked with 100 marked mussels. The recovery of mussels after six months exceeded 80% in all but one treatment group.

  6. Method and apparatus for processing a test sample to concentrate an analyte in the sample from a solvent in the sample

    DOEpatents

    Turner, T.D.; Beller, L.S.; Clark, M.L.; Klingler, K.M.

    1997-10-14

    A method of processing a test sample to concentrate an analyte in the sample from a solvent in the sample includes: (a) boiling the test sample containing the analyte and solvent in a boiling chamber to a temperature greater than or equal to the solvent boiling temperature and less than the analyte boiling temperature to form a rising sample vapor mixture; (b) passing the sample vapor mixture from the boiling chamber to an elongated primary separation tube, the separation tube having internal sidewalls and a longitudinal axis, the longitudinal axis being angled between vertical and horizontal and thus having an upper region and a lower region; (c) collecting the physically transported liquid analyte on the internal sidewalls of the separation tube; and (d) flowing the collected analyte along the angled internal sidewalls of the separation tube to and pass the separation tube lower region. The invention also includes passing a turbulence inducing wave through a vapor mixture to separate physically transported liquid second material from vaporized first material. Apparatus is also disclosed for effecting separations. Further disclosed is a fluidically powered liquid test sample withdrawal apparatus for withdrawing a liquid test sample from a test sample container and for cleaning the test sample container. 8 figs.

  7. Method and apparatus for processing a test sample to concentrate an analyte in the sample from a solvent in the sample

    DOEpatents

    Turner, Terry D.; Beller, Laurence S.; Clark, Michael L.; Klingler, Kerry M.

    1997-01-01

    A method of processing a test sample to concentrate an analyte in the sample from a solvent in the sample includes: a) boiling the test sample containing the analyte and solvent in a boiling chamber to a temperature greater than or equal to the solvent boiling temperature and less than the analyte boiling temperature to form a rising sample vapor mixture; b) passing the sample vapor mixture from the boiling chamber to an elongated primary separation tube, the separation tube having internal sidewalls and a longitudinal axis, the longitudinal axis being angled between vertical and horizontal and thus having an upper region and a lower region; c) collecting the physically transported liquid analyte on the internal sidewalls of the separation tube; and d) flowing the collected analyte along the angled internal sidewalls of the separation tube to and pass the separation tube lower region. The invention also includes passing a turbulence inducing wave through a vapor mixture to separate physically transported liquid second material from vaporized first material. Apparatus are also disclosed for effecting separations. Further disclosed is a fluidically powered liquid test sample withdrawal apparatus for withdrawing a liquid test sample from a test sample container and for cleaning the test sample container.

  8. Microwave acid digestion and preconcentration neutron activation analysis of biological and diet samples for iodine.

    PubMed

    Rao, R R; Chatt, A

    1991-07-01

    A simple preconcentration neutron activation analysis (PNAA) method has been developed for the determination of low levels of iodine in biological and nutritional materials. The method involves dissolution of the samples by microwave digestion in the presence of acids in closed Teflon bombs and preconcentration of total iodine, after reduction to iodide with hydrazine sulfate, by coprecipitation with bismuth sulfide. The effects of different factors such as acidity, time for complete precipitation, and concentrations of bismuth, sulfide, and diverse ions on the quantitative recovery of iodide have been studied. The absolute detection limit of the PNAA method is 5 ng of iodine. Precision of measurement, expressed in terms of relative standard deviation, is about 5% at 100 ppb and 10% at 20 ppb levels of iodine. The PNAA method has been applied to several biological reference materials and total diet samples.

  9. Random Sampling of Quantum States: a Survey of Methods. And Some Issues Regarding the Overparametrized Method

    NASA Astrophysics Data System (ADS)

    Maziero, Jonas

    2015-12-01

    The numerical generation of random quantum states (RQS) is an important procedure for investigations in quantum information science. Here, we review some methods that may be used for performing that task. We start by presenting a simple procedure for generating random state vectors, for which the main tool is the random sampling of unbiased discrete probability distributions (DPD). Afterwards, the creation of random density matrices is addressed. In this context, we first present the standard method, which consists in using the spectral decomposition of a quantum state for getting RQS from random DPDs and random unitary matrices. In the sequence, the Bloch vector parametrization method is described. This approach, despite being useful in several instances, is not in general convenient for RQS generation. In the last part of the article, we regard the overparametrized method (OPM) and the related Ginibre and Bures techniques. The OPM can be used to create random positive semidefinite matrices with unit trace from randomly produced general complex matrices in a simple way that is friendly for numerical implementations. We consider a physically relevant issue related to the possible domains that may be used for the real and imaginary parts of the elements of such general complex matrices. Subsequently, a too fast concentration of measure in the quantum state space that appears in this parametrization is noticed.

  10. Analytical methods for determination of anticoagulant rodenticides in biological samples.

    PubMed

    Imran, Muhammad; Shafi, Humera; Wattoo, Sardar Ali; Chaudhary, Muhammad Taimoor; Usman, Hafiz Faisal

    2015-08-01

    Anticoagulant rodenticides belong to a heterogeneous group of compounds which are used to kill rodents. They bind to enzyme complexes responsible for recycling of vitamin K, thus producing impairment in coagulation process. Rodenticides are among the most common house hold toxicants and exhibit wide variety of toxicities in non-target species especially in human, dogs and cats. This article reviews published analytical methods reported in literature for qualitative and quantitative determination of anticoagulant rodenticides in biological specimens. These techniques include high performance liquid chromatography coupled with ultraviolet and florescence detectors, liquid chromatography electrospray ionization tandem mass spectrometry, liquid chromatography with high resolution tandem mass spectrometry, ultra performance liquid chromatography mass spectrometry, gas chromatography mass spectrometry, ion chromatography with fluorescence detection, ion chromatography electrospray ionization ion trap mass spectrometry and ion chromatography electrospray ionization tandem mass spectrometry.

  11. Sparsity-weighted outlier FLOODing (OFLOOD) method: Efficient rare event sampling method using sparsity of distribution.

    PubMed

    Harada, Ryuhei; Nakamura, Tomotake; Shigeta, Yasuteru

    2016-03-30

    As an extension of the Outlier FLOODing (OFLOOD) method [Harada et al., J. Comput. Chem. 2015, 36, 763], the sparsity of the outliers defined by a hierarchical clustering algorithm, FlexDice, was considered to achieve an efficient conformational search as sparsity-weighted "OFLOOD." In OFLOOD, FlexDice detects areas of sparse distribution as outliers. The outliers are regarded as candidates that have high potential to promote conformational transitions and are employed as initial structures for conformational resampling by restarting molecular dynamics simulations. When detecting outliers, FlexDice defines a rank in the hierarchy for each outlier, which relates to sparsity in the distribution. In this study, we define a lower rank (first ranked), a medium rank (second ranked), and the highest rank (third ranked) outliers, respectively. For instance, the first-ranked outliers are located in a given conformational space away from the clusters (highly sparse distribution), whereas those with the third-ranked outliers are nearby the clusters (a moderately sparse distribution). To achieve the conformational search efficiently, resampling from the outliers with a given rank is performed. As demonstrations, this method was applied to several model systems: Alanine dipeptide, Met-enkephalin, Trp-cage, T4 lysozyme, and glutamine binding protein. In each demonstration, the present method successfully reproduced transitions among metastable states. In particular, the first-ranked OFLOOD highly accelerated the exploration of conformational space by expanding the edges. In contrast, the third-ranked OFLOOD reproduced local transitions among neighboring metastable states intensively. For quantitatively evaluations of sampled snapshots, free energy calculations were performed with a combination of umbrella samplings, providing rigorous landscapes of the biomolecules.

  12. Estimating time-correlation functions by sampling and unbiasing dynamically activated events.

    PubMed

    Athènes, Manuel; Marinica, Mihai-Cosmin; Jourdan, Thomas

    2012-11-21

    Transition path sampling is a rare-event method that estimates state-to-state time-correlation functions in many-body systems from samples of short trajectories. In this framework, it is proposed to bias the importance function using the lowest Jacobian eigenvalue moduli along the dynamical trajectory. A lowest eigenvalue modulus is related to the lowest eigenvalue of the Hessian matrix and is evaluated here using the Lanczos algorithm as in activation-relaxation techniques. This results in favoring the sampling of activated trajectories and enhancing the occurrence of the rare reactive trajectories of interest, those corresponding to transitions between locally stable states. Estimating the time-correlation functions involves unbiasing the sample of simulated trajectories which is done using the multi-state Bennett acceptance ratio (MBAR) method. To assess the performance of our procedure, we compute the time-correlation function associated with the migration of a vacancy in α-iron. The derivative of the estimated time-correlation function yields a migration rate in agreement with the one given by transition state theory. Besides, we show that the information relative to rejected trajectories can be recycled within MBAR, resulting in a substantial speed-up. Unlike original transition path-sampling, our approach does not require computing the reversible work to confine the trajectory endpoints to a reactive state.

  13. METHOD OF SUPPRESSING GASTROINTESTINAL UREASE ACTIVITY

    DOEpatents

    Visek, W.J.

    1963-04-23

    This patent shows a method of increasing the growth rate of chicks. Certain diacyl substituted ureas such as alloxan, murexide, and barbituric acid are added to their feed, thereby suppressing gastrointestinal urease activity and thus promoting growth. (AEC)

  14. Method for sequential injection of liquid samples for radioisotope separations

    DOEpatents

    Egorov, Oleg B.; Grate, Jay W.; Bray, Lane A.

    2000-01-01

    The present invention is a method of separating a short-lived daughter isotope from a longer lived parent isotope, with recovery of the parent isotope for further use. Using a system with a bi-directional pump and one or more valves, a solution of the parent isotope is processed to generate two separate solutions, one of which contains the daughter isotope, from which the parent has been removed with a high decontamination factor, and the other solution contains the recovered parent isotope. The process can be repeated on this solution of the parent isotope. The system with the fluid drive and one or more valves is controlled by a program on a microprocessor executing a series of steps to accomplish the operation. In one approach, the cow solution is passed through a separation medium that selectively retains the desired daughter isotope, while the parent isotope and the matrix pass through the medium. After washing this medium, the daughter is released from the separation medium using another solution. With the automated generator of the present invention, all solution handling steps necessary to perform a daughter/parent radionuclide separation, e.g. Bi-213 from Ac-225 "cow" solution, are performed in a consistent, enclosed, and remotely operated format. Operator exposure and spread of contamination are greatly minimized compared to the manual generator procedure described in U.S. patent application Ser. No. 08/789,973, now U.S. Pat. No. 5,749,042, herein incorporated by reference. Using 16 mCi of Ac-225 there was no detectable external contamination of the instrument components.

  15. Development of unmanned aerial vehicle (UAV) based high altitude balloon (HAB) platform for active aerosol sampling

    NASA Astrophysics Data System (ADS)

    Lateran, S.; Sedan, M. F.; Harithuddin, A. S. M.; Azrad, S.

    2016-10-01

    The knowledge on the abundance and diversity of the minute particles or aerosols in the earth's stratosphere is still in its infancy as aerosol sampling at high-altitude still possess a lot of challenges. Thus far, high-altitude aerosol sampling has been conducted mostly using manned flights, which requires enormous financial and logistical resources. There had been researches for the utilisation of high altitude balloon (HAB) for active and passive aerosol samplings within the stratosphere. However, the gathered samples in the payload were either brought down by controlling the balloon air pressure or were just dropped with a parachute to slow the descend speed in order to reduce the impact upon landing. In most cases, the drop location of the sample are unfavorable such as in the middle of the sea, dense foliage, etc. Hence a system that can actively sample aerosols at high-altitude and improve the delivery method in terms of quality and reliability using unmanned aerial vehicle (UAV) is designed and tested in this study.

  16. Electroosmotic sampling. Application to determination of ectopeptidase activity in organotypic hippocampal slice cultures.

    PubMed

    Xu, Hongjuan; Guy, Yifat; Hamsher, Amy; Shi, Guoyue; Sandberg, Mats; Weber, Stephen G

    2010-08-01

    We hypothesize that peptide-containing solutions pulled through tissue should reveal the presence and activity of peptidases in the tissue. Using the natural zeta-potential in the organotypic hippocampal slice culture (OHSC), physiological fluids can be pulled through the tissue with an electric field. The hydrolysis of the peptides present in the fluid drawn through the tissue can be determined using capillary HPLC with electrochemical detection of the biuret complexes of the peptides following a postcolumn reaction. We have characterized this new sampling method by measuring the flow rate, examining the use of internal standards, and examining cell death caused by sampling. The sampling flow rate ranges from 60 to 150 nL/min with a 150 microm (ID) sampling capillary with an electric field (at the tip of the capillary) from 30 to 60 V/cm. Cell death can be negligible with controlled sampling conditions. Using this sampling approach, we have electroosmotically pulled Leu-enkephalin through OHSCs to identify ectopeptidase activity in the CA3 region. These studies show that a bestatin-sensitive aminopeptidase may be critical for the hydrolysis of exogenous Leu-enkephalin, a neuropeptide present in the CA3 region of OHSCs.

  17. Electroosmotic Sampling. Application to Determination of Ectopeptidase Activity in Organotypic Hippocampal Slice Cultures

    PubMed Central

    Xu, Hongjuan; Guy, Yifat; Hamsher, Amy; Shi, Guoyue; Sandberg, Mats; Weber, Stephen G.

    2010-01-01

    We hypothesize that peptide-containing solutions pulled through tissue should reveal the presence and activity of peptidases in the tissue. Using the natural ζ-potential in the organotypic hippocampal slice culture (OHSC), physiological fluids can be pulled through the tissue with an electric field. The hydrolysis of the peptides present in the fluid drawn through the tissue can be determined using capillary HPLC with electrochemical detection of the biuret complexes of the peptides following a postcolumn reaction. We have characterized this new sampling method by measuring the flow rate, examining the use of internal standards, and examining cell death caused by sampling. The sampling flow rate ranges from 60 to 150 nL/min with a 150 μm (ID) sampling capillary with an electric field (at the tip of the capillary) from 30 to 60 V/cm. Cell death can be negligible with controlled sampling conditions. Using this sampling approach, we have electroosmotically pulled Leu-enkephalin through OHSCs to identify ectopeptidase activity in the CA3 region. These studies show that a bestatin-sensitive aminopeptidase may be critical for the hydrolysis of exogenous Leu-enkephalin, a neuropeptide present in the CA3 region of OHSCs. PMID:20669992

  18. Encapsulation method for maintaining biodecontamination activity

    DOEpatents

    Rogers, Robert D.; Hamilton, Melinda A.; Nelson, Lee O.; Benson, Jennifer; Green, Martin J.; Milner, Timothy N.

    2006-04-11

    A method for maintaining the viability and subsequent activity of microorganisms utilized in a variety of environments to promote biodecontamination of surfaces. One application involves the decontamination of concrete surfaces. Encapsulation of microbial influenced degradation (MID) microorganisms has shown that MID activity is effectively maintained under passive conditions, that is, without manual addition of moisture or nutrients, for an extended period of time.

  19. Encapsulation method for maintaining biodecontamination activity

    DOEpatents

    Rogers, Robert D.; Hamilton, Melinda A.; Nelson, Lee O.; Benson, Jennifer; Green, Martin J.; Milner, Timothy N.

    2002-01-01

    A method for maintaining the viability and subsequent activity of microorganisms utilized in a variety of environments to promote biodecontamination of surfaces. One application involves the decontamination of concrete surfaces. Encapsulation of microbial influenced degradation (MID) microorganisms has shown that MID activity is effectively maintained under passive conditions, that is, without manual addition of moisture or nutrients, for an extended period of time.

  20. [Comparative Analysis of Spectrophotometric Methods of the Protein Measurement in the Pectic Polysaccharide Samples].

    PubMed

    Ponomareva, S A; Golovchenko, V V; Patova, O A; Vanchikova, E V; Ovodov, Y S

    2015-01-01

    For the assay to reliability of determination of the protein content in the pectic polysaccharide samples by absorbance in the ultraviolet and visible regions of the spectrum a comparison of the eleven techniques called Flores, Lovry, Bradford, Sedmak, Rueman (ninhydrin reaction) methods, the method of ultraviolet spectrophotometry, the method Benedict's reagent, the method Nessler's reagent, the method with amide black, the bicinchoninic reagent and the biuret method was carried out. The data obtained show that insufficient sensitivity of the seven methods from the listed techniques doesn't allow their usage for determination of protein content in pectic polysaccharide samples. But the Lowry, Bradford, Sedmak methods, and the method Nessler's reagent may be used for determination of protein content in pectic polysaccharide samples, and the Bradford method is advisable for protein contaminants content determination in pectic polysaccharide samples in case protein content is less than 15%, and the Lowry method--for samples is more than 15%.

  1. Chemical compositions and antimicrobial activities of four different Anatolian propolis samples.

    PubMed

    Uzel, Ataç; Sorkun, Kadriye; Onçağ, Ozant; Cogŭlu, Dilşah; Gençay, Omür; Salih, Bekir

    2005-01-01

    Propolis means a gum that is gathered by bees from various plants. It is known for its biological properties, having antibacterial, antifungal and healing properties. The aims of this study were to evaluate the antimicrobial activity of four different Anatolian propolis samples on different groups of microorganisms including some oral pathogens and comparison between their chemical compositions. Ethanol extracts of propolis (EEP) were prepared from four different Anatolian propolis samples and examined whether EEP inhibit the growth of the test microorganisms or not. For the antimicrobial activity assays, minimum inhibitory concentrations (MIC) were determined by using macrodilution method. The MIC values of the most effective propolis (TB) were 2 microg/ml for Streptococcus sobrinus and Enterococcus faecalis, 4 microg/ml for Micrococcus luteus, Candida albicans and C. krusei, 8 microg/ml for Streptococcus mutans, Staphylococcus aureus, Staphylococcus epidermidis and Enterobacter aerogenes, 16 microg/ml for Escherichia coli and C. tropicalis and 32 microg/ml for Salmonella typhimurium and Pseudomonas aeruginosa. The chemical compositions of EEP's were determined by high-temperature high-resolution gas chromatography coupled to mass spectrometry. The main compounds of four Anatolian propolis samples were flavonoids such as pinocembrin, pinostropin, isalpinin, pinobanksin, quercetin, naringenin, galangine and chrysin. Although propolis samples were collected from different regions of Anatolia all showed significant antimicrobial activity against the Gram positive bacteria and yeasts. Propolis can prevent dental caries since it demonstrated significant antimicrobial activity against the microorganisms such as Streptococcus mutans, Streptococcus sobrinus and C. albicans, which involves in oral diseases.

  2. Surveying immigrants without sampling frames - evaluating the success of alternative field methods.

    PubMed

    Reichel, David; Morales, Laura

    2017-01-01

    This paper evaluates the sampling methods of an international survey, the Immigrant Citizens Survey, which aimed at surveying immigrants from outside the European Union (EU) in 15 cities in seven EU countries. In five countries, no sample frame was available for the target population. Consequently, alternative ways to obtain a representative sample had to be found. In three countries 'location sampling' was employed, while in two countries traditional methods were used with adaptations to reach the target population. The paper assesses the main methodological challenges of carrying out a survey among a group of immigrants for whom no sampling frame exists. The samples of the survey in these five countries are compared to results of official statistics in order to assess the accuracy of the samples obtained through the different sampling methods. It can be shown that alternative sampling methods can provide meaningful results in terms of core demographic characteristics although some estimates differ to some extent from the census results.

  3. Measurement of bedload transport in sand-bed rivers: a look at two indirect sampling methods

    USGS Publications Warehouse

    Holmes, Robert R.; Gray, John R.; Laronne, Jonathan B.; Marr, Jeffrey D.G.

    2010-01-01

    Sand-bed rivers present unique challenges to accurate measurement of the bedload transport rate using the traditional direct sampling methods of direct traps (for example the Helley-Smith bedload sampler). The two major issues are: 1) over sampling of sand transport caused by “mining” of sand due to the flow disturbance induced by the presence of the sampler and 2) clogging of the mesh bag with sand particles reducing the hydraulic efficiency of the sampler. Indirect measurement methods hold promise in that unlike direct methods, no transport-altering flow disturbance near the bed occurs. The bedform velocimetry method utilizes a measure of the bedform geometry and the speed of bedform translation to estimate the bedload transport through mass balance. The bedform velocimetry method is readily applied for the estimation of bedload transport in large sand-bed rivers so long as prominent bedforms are present and the streamflow discharge is steady for long enough to provide sufficient bedform translation between the successive bathymetric data sets. Bedform velocimetry in small sandbed rivers is often problematic due to rapid variation within the hydrograph. The bottom-track bias feature of the acoustic Doppler current profiler (ADCP) has been utilized to accurately estimate the virtual velocities of sand-bed rivers. Coupling measurement of the virtual velocity with an accurate determination of the active depth of the streambed sediment movement is another method to measure bedload transport, which will be termed the “virtual velocity” method. Much research remains to develop methods and determine accuracy of the virtual velocity method in small sand-bed rivers.

  4. Recent developments on field gas extraction and sample preparation methods for radiokrypton dating of groundwater

    NASA Astrophysics Data System (ADS)

    Yokochi, Reika

    2016-09-01

    Current and foreseen population growths will lead to an increased demand in freshwater, large quantities of which is stored as groundwater. The ventilation age is crucial to the assessment of groundwater resources, complementing the hydrological model approach based on hydrogeological parameters. Ultra-trace radioactive isotopes of Kr (81 Kr and 85 Kr) possess the ideal physical and chemical properties for groundwater dating. The recent advent of atom trap trace analyses (ATTA) has enabled determination of ultra-trace noble gas radioisotope abundances using 5-10 μ L of pure Kr. Anticipated developments will enable ATTA to analyze radiokrypton isotope abundances at high sample throughput, which necessitates simple and efficient sample preparation techniques that are adaptable to various sample chemistries. Recent developments of field gas extraction devices and simple and rapid Kr separation method at the University of Chicago are presented herein. Two field gas extraction devices optimized for different sampling conditions were recently designed and constructed, aiming at operational simplicity and portability. A newly developed Kr purification system enriches Kr by flowing a sample gas through a moderately cooled (138 K) activated charcoal column, followed by a gentle fractionating desorption. This simple process uses a single adsorbent and separates 99% of the bulk atmospheric gases from Kr without significant loss. The subsequent two stages of gas chromatographic separation and a hot Ti sponge getter further purify the Kr-enriched gas. Abundant CH4 necessitates multiple passages through one of the gas chromatographic separation columns. The presented Kr separation system has a demonstrated capability of extracting Kr with > 90% yield and 99% purity within 75 min from 1.2 to 26.8 L STP of atmospheric air with various concentrations of CH4. The apparatuses have successfully been deployed for sampling in the field and purification of groundwater samples.

  5. Sampling methods for the quasistationary regime of epidemic processes on regular and complex networks

    NASA Astrophysics Data System (ADS)

    Sander, Renan S.; Costa, Guilherme S.; Ferreira, Silvio C.

    2016-10-01

    A major hurdle in the simulation of the steady state of epidemic processes is that the system will unavoidably visit an absorbing, disease-free state at sufficiently long times due to the finite size of the networks where epidemics evolves. In the present work, we compare different quasistationary (QS) simulation methods where the absorbing states are suitably handled and the thermodynamical limit of the original dynamics can be achieved. We analyze the standard QS (SQS) method, where the sampling is constrained to active configurations, the reflecting boundary condition (RBC), where the dynamics returns to the pre-absorbing configuration, and hub reactivation (HR), where the most connected vertex of the network is reactivated after a visit to an absorbing state. We apply the methods to the contact process (CP) and susceptible-infected-susceptible (SIS) models on regular and scale free networks. The investigated methods yield the same epidemic threshold for both models. For CP, that undergoes a standard collective phase transition, the methods are equivalent. For SIS, whose phase transition is ruled by the hub mutual reactivation, the SQS and HR methods are able to capture localized epidemic phases while RBC is not. We also apply the autocorrelation time as a tool to characterize the phase transition and observe that this analysis provides the same finite-size scaling exponents for the critical relaxation time for the investigated methods. Finally, we verify the equivalence between RBC method and a weak external field for epidemics on networks.

  6. 7 CFR 32.402 - Samples of mohair top grades; method of obtaining.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... through 20s. (b) Each application for standard samples of mohair top shall be upon an application form... 7 Agriculture 2 2010-01-01 2010-01-01 false Samples of mohair top grades; method of obtaining. 32... STANDARD CONTAINER REGULATIONS PURCHASE OF GREASE MOHAIR AND MOHAIR TOP SAMPLES § 32.402 Samples of...

  7. A Typology of Mixed Methods Sampling Designs in Social Science Research

    ERIC Educational Resources Information Center

    Onwuegbuzie, Anthony J.; Collins, Kathleen M. T.

    2007-01-01

    This paper provides a framework for developing sampling designs in mixed methods research. First, we present sampling schemes that have been associated with quantitative and qualitative research. Second, we discuss sample size considerations and provide sample size recommendations for each of the major research designs for quantitative and…

  8. 40 CFR 80.8 - Sampling methods for gasoline and diesel fuel.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Sampling methods for gasoline and... gasoline and diesel fuel. The sampling methods specified in this section shall be used to collect samples of gasoline and diesel fuel for purposes of determining compliance with the requirements of this...

  9. 40 CFR 80.8 - Sampling methods for gasoline and diesel fuel.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Sampling methods for gasoline and... gasoline and diesel fuel. The sampling methods specified in this section shall be used to collect samples of gasoline and diesel fuel for purposes of determining compliance with the requirements of this...

  10. 40 CFR 80.8 - Sampling methods for gasoline and diesel fuel.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Sampling methods for gasoline and... gasoline and diesel fuel. The sampling methods specified in this section shall be used to collect samples of gasoline and diesel fuel for purposes of determining compliance with the requirements of this...

  11. A Sequential Optimization Sampling Method for Metamodels with Radial Basis Functions

    PubMed Central

    Pan, Guang; Ye, Pengcheng; Yang, Zhidong

    2014-01-01

    Metamodels have been widely used in engineering design to facilitate analysis and optimization of complex systems that involve computationally expensive simulation programs. The accuracy of metamodels is strongly affected by the sampling methods. In this paper, a new sequential optimization sampling method is proposed. Based on the new sampling method, metamodels can be constructed repeatedly through the addition of sampling points, namely, extrema points of metamodels and minimum points of density function. Afterwards, the more accurate metamodels would be constructed by the procedure above. The validity and effectiveness of proposed sampling method are examined by studying typical numerical examples. PMID:25133206

  12. Predictive Sampling of Rare Conformational Events in Aqueous Solution: Designing a Generalized Orthogonal Space Tempering Method.

    PubMed

    Lu, Chao; Li, Xubin; Wu, Dongsheng; Zheng, Lianqing; Yang, Wei

    2016-01-12

    In aqueous solution, solute conformational transitions are governed by intimate interplays of the fluctuations of solute-solute, solute-water, and water-water interactions. To promote molecular fluctuations to enhance sampling of essential conformational changes, a common strategy is to construct an expanded Hamiltonian through a series of Hamiltonian perturbations and thereby broaden the distribution of certain interactions of focus. Due to a lack of active sampling of configuration response to Hamiltonian transitions, it is challenging for common expanded Hamiltonian methods to robustly explore solvent mediated rare conformational events. The orthogonal space sampling (OSS) scheme, as exemplified by the orthogonal space random walk and orthogonal space tempering methods, provides a general framework for synchronous acceleration of slow configuration responses. To more effectively sample conformational transitions in aqueous solution, in this work, we devised a generalized orthogonal space tempering (gOST) algorithm. Specifically, in the Hamiltonian perturbation part, a solvent-accessible-surface-area-dependent term is introduced to implicitly perturb near-solute water-water fluctuations; more importantly in the orthogonal space response part, the generalized force order parameter is generalized as a two-dimension order parameter set, in which essential solute-solvent and solute-solute components are separately treated. The gOST algorithm is evaluated through a molecular dynamics simulation study on the explicitly solvated deca-alanine (Ala10) peptide. On the basis of a fully automated sampling protocol, the gOST simulation enabled repetitive folding and unfolding of the solvated peptide within a single continuous trajectory and allowed for detailed constructions of Ala10 folding/unfolding free energy surfaces. The gOST result reveals that solvent cooperative fluctuations play a pivotal role in Ala10 folding/unfolding transitions. In addition, our assessment

  13. Enhanced Sampling in Free Energy Calculations: Combining SGLD with the Bennett's Acceptance Ratio and Enveloping Distribution Sampling Methods.

    PubMed

    König, Gerhard; Miller, Benjamin T; Boresch, Stefan; Wu, Xiongwu; Brooks, Bernard R

    2012-10-09

    One of the key requirements for the accurate calculation of free energy differences is proper sampling of conformational space. Especially in biological applications, molecular dynamics simulations are often confronted with rugged energy surfaces and high energy barriers, leading to insufficient sampling and, in turn, poor convergence of the free energy results. In this work, we address this problem by employing enhanced sampling methods. We explore the possibility of using self-guided Langevin dynamics (SGLD) to speed up the exploration process in free energy simulations. To obtain improved free energy differences from such simulations, it is necessary to account for the effects of the bias due to the guiding forces. We demonstrate how this can be accomplished for the Bennett's acceptance ratio (BAR) and the enveloping distribution sampling (EDS) methods. While BAR is considered among the most efficient methods available for free energy calculations, the EDS method developed by Christ and van Gunsteren is a promising development that reduces the computational costs of free energy calculations by simulating a single reference state. To evaluate the accuracy of both approaches in connection with enhanced sampling, EDS was implemented in CHARMM. For testing, we employ benchmark systems with analytical reference results and the mutation of alanine to serine. We find that SGLD with reweighting can provide accurate results for BAR and EDS where conventional molecular dynamics simulations fail. In addition, we compare the performance of EDS with other free energy methods. We briefly discuss the implications of our results and provide practical guidelines for conducting free energy simulations with SGLD.

  14. Sample Energy Conservation Education Activities for Elementary School Students.

    ERIC Educational Resources Information Center

    Allen, Rodney F., Ed.; LaHart, David E., Ed.

    The booklet contains learning activities for introducing energy and conservation concepts into the existing elementary school curriculum. The activities were developed by Palm Beach County teachers during a one-week workshop. A framework of ideas is divided into three functional categories: universe of energy, living systems and energy, and social…

  15. Monitoring benthic aIgal communides: A comparison of targeted and coefficient sampling methods

    USGS Publications Warehouse

    Edwards, Matthew S.; Tinker, M. Tim

    2009-01-01

    Choosing an appropriate sample unit is a fundamental decision in the design of ecological studies. While numerous methods have been developed to estimate organism abundance, they differ in cost, accuracy and precision.Using both field data and computer simulation modeling, we evaluated the costs and benefits associated with two methods commonly used to sample benthic organisms in temperate kelp forests. One of these methods, the Targeted Sampling method, relies on different sample units, each "targeted" for a specific species or group of species while the other method relies on coefficients that represent ranges of bottom cover obtained from visual esti-mates within standardized sample units. Both the field data and the computer simulations suggest that both methods yield remarkably similar estimates of organism abundance and among-site variability, although the Coefficient method slightly underestimates variability among sample units when abundances are low. In contrast, the two methods differ considerably in the effort needed to sample these communities; the Targeted Sampling requires more time and twice the personnel to complete. We conclude that the Coefficent Sampling method may be better for environmental monitoring programs where changes in mean abundance are of central concern and resources are limiting, but that the Targeted sampling methods may be better for ecological studies where quantitative relationships among species and small-scale variability in abundance are of central concern.

  16. Comparative analysis of three methods for HPV DNA detection in cervical samples.

    PubMed

    Michelli, Elvia; Téllez, Luis; Mendoza, José-Andrés; Jürgensen, Claudia; Muñoz, Maritza; Pérez, Saberio; Mosqueda, Noraida; Hernández, Erick; Noguera, María-Eugenia; Callejas, Diana; Correnti, María; Cavazza, María-Eugenia; Vielma, Silvana

    2011-12-01

    High risk HPV infection is considered to play a central role in cervical carcinogenesis. HPV DNA testing has shown to be a very useful tool for screening and following cervical infections. The aim of this study was to compare three methods for HPV DNA detection, along with cytology and colposcopy analysis. Cervical samples were collected from 100 sexually active women in Mérida, western Venezuela. HPV infection was screened using Hybrid-Capture 2 (HC2), L1-Nested-PCR and E6/E7-PCR assays. 40% of the samples (40/100) were HPV positive by at least one of the DNA detection methods. HC2 detected HPV in 12% specimens. L1- and E6/E7-PCRs showed 50% sensitivity and 77% specificity.The agreement rate between HC2 and both PCR assays was 65%. Kappa value showed moderate concordance between HC2 and both PCR methods (kappa=0.55; CI 95%). Also moderate concordance was seen when L1- and E6/E7-PCRs were compared (kappa=0.48; CI 95%). There was a significant association between the Schiller test and E6/E7-PCR (p=0.006) for HPV infection. An acceptable agreement between all three assays for HPV detection was observed. Nevertheless, different PCR formats need to be further analyzed in order to make the right choice of method for HPV testing.

  17. Jazz Listening Activities: Children's Literature and Authentic Music Samples.

    ERIC Educational Resources Information Center

    McDonald, Nan L.; Fisher, Douglas; Helzer, Rick

    2002-01-01

    Describes a unit that is appropriate for upper elementary and middle school students that focuses on jazz music using biographies about jazz musicians. Discusses the five sections of the unit. Includes a list of "Suggested Jazz Listening Samples," jazz videos, and a bibliography of resources related to jazz music. (CMK)

  18. 137Cs re-sampling as a method for soil erosion assessment in Alpine grasslands

    NASA Astrophysics Data System (ADS)

    Arata, Laura; Meusburger, Katrin; Bissig, Nicole; Mabit, Lionel; Alewell, Christine

    2014-05-01

    Over the past decades, radioactive fallout 137Cs has been used as a tracer to provide information on soil erosion and sedimentation rates. However, the method may produce relatively large uncertainties in Alpine grasslands. The latter difficulties are caused by a combination of (i) the heterogeneous distribution of atmospheric 137Cs Chernobyl fallout, (ii) the partly snow covered ground in Alpine areas during the fallout event in April 1986, which results in inhomogeneous 137Cs distribution during snow melt and (iii) uncertainties in finding undisturbed references sites in the geomorphological and anthropogenic highly active slopes of the Alps. To overcome these difficulties, our aim is to replace the classical 137Cs approach, where an undisturbed reference site is compared to erosional sites, with a re-sampling approach, where we re-sample sites which have already been measured for 137Cs inventories in the past. Thus, we use temporal instead of spatial reference. The study area is located in the Central Swiss Alps in the Urseren Valley. Potential erosional sites have been sampled in 2007 and re-sampled in 2012. Two different grassland types were investigated: hayfield (2 sites) and pasture without dwarf shrubs (3 sites). For each site, 4 to 9 sampling points have been defined, and at each point two soil samples have been collected. To reduce the random error, the two soil samples were bulked prior to gamma-analysis. 137Cs inventories of the two sampling years were calculated and used to assess recent soil erosion in the experimental sites. Our results show that within the 5 years measurable soil erosion and deposition processes have occurred within the sites, as indicated by the relevant difference between the 137Cs inventories of 2007 and 2012. 64% of the sites exhibit a decrease in 137Cs inventories, 20% of the sites an increase, and the remaining 16% no significant difference. In particular, hayfield sites have been affected by erosion processes, mostly due to

  19. Differences in Movement Pattern and Detectability between Males and Females Influence How Common Sampling Methods Estimate Sex Ratio

    PubMed Central

    Rodrigues, João Fabrício Mota; Coelho, Marco Túlio Pacheco

    2016-01-01

    Sampling the biodiversity is an essential step for conservation, and understanding the efficiency of sampling methods allows us to estimate the quality of our biodiversity data. Sex ratio is an important population characteristic, but until now, no study has evaluated how efficient are the sampling methods commonly used in biodiversity surveys in estimating the sex ratio of populations. We used a virtual ecologist approach to investigate whether active and passive capture methods are able to accurately sample a population’s sex ratio and whether differences in movement pattern and detectability between males and females produce biased estimates of sex-ratios when using these methods. Our simulation allowed the recognition of individuals, similar to mark-recapture studies. We found that differences in both movement patterns and detectability between males and females produce biased estimates of sex ratios. However, increasing the sampling effort or the number of sampling days improves the ability of passive or active capture methods to properly sample sex ratio. Thus, prior knowledge regarding movement patterns and detectability for species is important information to guide field studies aiming to understand sex ratio related patterns. PMID:27441554

  20. Microscopic and mesoscopic structural features of an activated carbon sample, prepared from sorghum via activation by phosphoric acid

    SciTech Connect

    Temleitner, László; Pusztai, László; Rubio-Arroyo, Manuel F.; Aguilar-López, Sergio; Pizio, Orest

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► Preparation of a new activated carbon sample from sorghum. ► Characterization by adsorption/desorption methods. ► Determination of the structure by synchrotron X-ray diffraction. ► The sample is amorphous and contains distorted graphene fragments. ► A characteristic nanoscale distance is established from the radial distribution function. -- Abstract: An acidic chemical activation procedure has been used for preparing activated carbon with a surface area exceeding 1000 m{sup 2}/g from sorghum. In order to reveal structural features, synchrotron X-ray diffraction measurements have been performed. The structure of the material has been characterized by the total scattering structure factor and the radial distribution function describing short-range arrangement of atoms at distances of the order of a few atomic diameters as well as correlations at a longer scale, of the order of nanometers. The atomic arrangement has been found to be consistent with that of amorphous graphite-like carbon. As far as the mesoscopic structure is concerned, the presence of a characteristic distance is suggested on the basis of the clear nanometer scale oscillations of the radial distribution function, which distance may be assigned as the mesopore size in the material. It is suggested that the approach devized here may later be applied routinely for other activated carbon samples, too, for characterizing atomic and nanoscale order simultaneously.

  1. Measurement of radon potential from soil using a special method of sampling

    NASA Astrophysics Data System (ADS)

    Cosma, Constantin; Papp, Botond; Moldovan, Mircea; Cosma, Victor; Cindea, Ciprian; Suciu, Liviu; Apostu, Adelina

    2010-10-01

    Soil radon gas and/or its exhalation rate are used as indicators for some applications, such as uranium exploration, indoor radon concentration, seismic activity, location of subsurface faults, etc., and also in the studies where the main interest is the field verification of radon transport models. This work proposes a versatile method for the soil radon sampling using a special manner of pumping. The soil gas is passed through a column of charcoal by using passive pumping. A plastic bottle filled with water is coupled to an activated charcoal column and the flow of water through an adjustable hole made at the bottom of bottle assures a controlled gas flow from the soil. The results obtained for the activity of activated charcoal are in the range of 20-40 kBq/m3, for a depth of approximately 0.8 m. The results obtained by this method were confirmed by simultaneous measurements using LUK 3C device for soil radon measurements. Possible applications for the estimation of radon soil potential are discussed.

  2. Different methods for extracting bacteria from freshwater sediment and a simple method to measure bacterial production in sediment samples.

    PubMed

    dos Santos Furtado, A L; Casper, P

    2000-08-01

    The efficiency of different treatments was tested to extract bacterial cells from freshwater sediment samples. The influence of sonication, density gradient centrifugation, fixation by formalin and centrifugation speed on bacterial recovery was investigated. The method developed by Smith and Azam [Mar. Microb. Food Webs 6 (1992) 107] to measure microbial activity on bacterioplankton (3H-leucine incorporation), was also evaluated in sediment samples. After 1 min of sonication bacterial abundance was reduced by about 47% in diluted sediments with tetrasodium pyrophosphate. With the addition of Percoll after sonication, bacterial counts were not significantly different (P<0.05). Fixation by formalin increased bacterial counts using sonication. However, higher bacterial abundance was estimated in non-sonicated samples. Bacterial abundance in samples centrifuged at 7000xg with and without Percoll was not significantly different (P<0.05). Highest bacterial abundance was obtained after centrifugation at low speed (750xg). Bacterial abundance decreased with higher centrifugation speed (750, 1500 and 3000xg), the difference, however, was not significant. Bacterial production ranged from 0.10 microg C cm(-3) d(-1) in autoclaved sediment to 0. 27 microg C cm(-3) d(-1) in untreated sediment. The radioactivity measured in controls of both untreated and autoclaved sediment was high (70 and 91%, respectively), indicating a high level of leucine adsorption in sediment particles. In contrast, radioactivity in control samples previously centrifuged was markedly lower (6%). Despite the high values of radioactivity in the controls, bacterial production in untreated sediment was significantly higher than in centrifuged sediment (P<0.05).

  3. Enhanced Stability of Blood Matrices Using a Dried Sample Spot Assay to Measure Human Butyrylcholinesterase Activity and Nerve Agent Adducts

    PubMed Central

    Perez, Jonas W.; Pantazides, Brooke G.; Watson, Caroline M.; Thomas, Jerry D.; Blake, Thomas A.; Johnson, Rudolph C.

    2015-01-01

    Dried matrix spots are safer to handle and easier to store than wet blood products, but factors such as intra-spot variability and unknown sample volumes have limited their appeal as a sampling format for quantitative analyses. In this work, we introduce a dried spot activity assay for quantifying butyrylcholinesterase (BChE) specific activity which is BChE activity normalized to the total protein content in a sample spot. The method was demonstrated with blood, serum, and plasma spotted on specimen collection devices (cards) which were extracted to measure total protein and BChE activity using a modified Ellman assay. Activity recovered from dried spots was ∼80% of the initial spotted activity for blood and >90% for plasma and serum. Measuring total protein in the sample and calculating specific activity substantially improved quantification and reduced intra-spot variability. Analyte stability of nerve agent adducts was also evaluated, and the results obtained via BChE-specific activity measurements were confirmed by quantification of BChE adducts using a previously established LC-MS/MS method. The spotted samples were up to 10-times more resistant to degradation compared to unspotted control samples when measuring BChE inhibition by the nerve agents sarin and VX. Using this method, both BChE activity and adducts can be accurately measured from a dried sample spot. This use of a dried sample spot with normalization to total protein is robust, demonstrates decreased intra-spot variability without the need to control for initial sample volume, and enhances analyte stability. PMID:25955132

  4. A neutron activation analysis procedure for the determination of uranium, thorium and potassium in geologic samples

    USGS Publications Warehouse

    Aruscavage, P. J.; Millard, H.T.

    1972-01-01

    A neutron activation analysis procedure was developed for the determination of uranium, thorium and potassium in basic and ultrabasic rocks. The three elements are determined in the same 0.5-g sample following a 30-min irradiation in a thermal neutron flux of 2??1012 n??cm-2??sec-1. Following radiochemical separation, the nuclides239U (T=23.5 m),233Th (T=22.2 m) and42K (T=12.36 h) are measured by ??-counting. A computer program is used to resolve the decay curves which are complex owing to contamination and the growth of daughter activities. The method was used to determine uranium, throium and potassium in the U. S. Geological Survey standard rocks DTS-1, PCC-1 and BCR-1. For 0.5-g samples the limits of detection for uranium, throium and potassium are 0.7, 1.0 and 10 ppb, respectively. ?? 1972 Akade??miai Kiado??.

  5. A method for measuring total thiaminase activity in fish tissues

    USGS Publications Warehouse

    Zajicek, James L.; Tillitt, Donald E.; Honeyfield, Dale C.; Brown, Scott B.; Fitzsimons, John D.

    2005-01-01

    An accurate, quantitative, and rapid method for the measurement of thiaminase activity in fish samples is required to provide sufficient information to characterize the role of dietary thiaminase in the onset of thiamine deficiency in Great Lakes salmonines. A radiometric method that uses 14C-thiamine was optimized for substrate and co-substrate (nicotinic acid) concentrations, incubation time, and sample dilution. Total thiaminase activity was successfully determined in extracts of selected Great Lakes fishes and invertebrates. Samples included whole-body and selected tissues of forage fishes. Positive control material prepared from frozen alewives Alosa pseudoharengus collected in Lake Michigan enhanced the development and application of the method. The method allowed improved discrimination of thiaminolytic activity among forage fish species and their tissues. The temperature dependence of the thiaminase activity observed in crude extracts of Lake Michigan alewives followed a Q10 = 2 relationship for the 1-37??C temperature range, which is consistent with the bacterial-derived thiaminase I protein. ?? Copyright by the American Fisheries Society 2005.

  6. A method to optimize sampling locations for measuring indoor air distributions

    NASA Astrophysics Data System (ADS)

    Huang, Yan; Shen, Xiong; Li, Jianmin; Li, Bingye; Duan, Ran; Lin, Chao-Hsin; Liu, Junjie; Chen, Qingyan

    2015-02-01

    Indoor air distributions, such as the distributions of air temperature, air velocity, and contaminant concentrations, are very important to occupants' health and comfort in enclosed spaces. When point data is collected for interpolation to form field distributions, the sampling locations (the locations of the point sensors) have a significant effect on time invested, labor costs and measuring accuracy on field interpolation. This investigation compared two different sampling methods: the grid method and the gradient-based method, for determining sampling locations. The two methods were applied to obtain point air parameter data in an office room and in a section of an economy-class aircraft cabin. The point data obtained was then interpolated to form field distributions by the ordinary Kriging method. Our error analysis shows that the gradient-based sampling method has 32.6% smaller error of interpolation than the grid sampling method. We acquired the function between the interpolation errors and the sampling size (the number of sampling points). According to the function, the sampling size has an optimal value and the maximum sampling size can be determined by the sensor and system errors. This study recommends the gradient-based sampling method for measuring indoor air distributions.

  7. Identification of Volatile Organic Compounds (VOCs) From Photochemical Activity in Snow Samples

    NASA Astrophysics Data System (ADS)

    Kos, G.; Ariya, P. A.

    2004-05-01

    The occurrence of VOCs in snow has been observed and can be related to anthropogenic emissions and biological activity. Photochemistry and microorganisms play a major role in the transformation of compounds in different compartments of the global ecosystem. Studies so far focused on the determination of single analytes or a class of compounds - mainly of anthropogenic origin (e.g. halogenated aromatic hydrocarbons) - that were considered important with regard to health and environmental concerns. Broader studies that describe a range of different compounds with different functionalities are relatively rare, especially for those of biological origin. The presented study investigated the formation of VOCs in snow samples and their connection with microbiological activity. The main aim was to pre-concentrate, identify and quantify volatile organic compounds. Snow samples were collected in an urban environment (Montreal, Canada) with sterilized containers. Samples were transferred into a heated reaction flask, where the sample was melted. A two-trap system was employed for pre-concentration: The first trap was used for water removal. The second trap was used for the collection of expected analytes by removing volatiles from the circulating air. Circulation was maintained with a pump at atmospheric pressure. Adsorption to glass walls of the reaction flask was prevented with halocarbon wax coating. Different sterilization methods were employed to suppress microbiological activity in order to collect background data and identify compounds of biological origin. VOC concentration and compound identification was performed with gas chromatography and mass spectrometric detection (GC-MS) by taking a sample with a gas-tight syringe through a septum-port. The sample was directly injected into the GC system. Compounds were identified by their respective mass spectra and included aldehydes and alcohols.

  8. The method of radioactive tracer for measuring the amount of inorganic nanoparticles in biological samples

    NASA Astrophysics Data System (ADS)

    Buzulukov, Yu; Antsiferova, A.; Demin, V. A.; Demin, V. F.; Kashkarov, P.

    2015-11-01

    The method to measure the mass of inorganic nanoparticles in biological (or any other samples) using nanoparticles labeled with radioactive tracers is developed and applied to practice. The tracers are produced in original nanoparticles by radioactive activation of some of their atomic nuclei. The method of radioactive tracers demonstrates a sensitivity, specificity and accuracy equal or better than popular methods of optical and mass spectrometry, or electron microscopy and has some specific advantages. The method can be used for study of absorption, distribution, metabolism and excretion in living organism, as well as in ecological and fundamental research. It was used in practice to study absorption, distribution, metabolism and excretion of nanoparticles of Ag, Au, Se, ZnO, TiO2 as well as to study transportation of silver nanoparticles through the barriers of blood-brain, placenta and milk gland of rats. Brief descriptions of data obtained in experiments with application of this method included in the article. The method was certified in Russian Federation standard system GOST-R and recommended by the Russian Federation regulation authority ROSPOTREBNADZOR for measuring of toxicokinetic and organotropy parameters of nanoparticles.

  9. Toxin activity assays, devices, methods and systems therefor

    DOEpatents

    Koh, Chung-Yan; Schaff, Ulrich Y.; Sommer, Gregory Jon

    2016-04-05

    Embodiments of the present invention are directed toward devices, system and method for conducting toxin activity assay using sedimentation. The toxin activity assay may include generating complexes which bind to a plurality of beads in a fluid sample. The complexes may include a target toxin and a labeling agent, or may be generated due to presence of active target toxin and/or labeling agent designed to be incorporated into complexes responsive to the presence of target active toxin. The plurality of beads including the complexes may be transported through a density media, wherein the density media has a lower density than a density of the beads and higher than a density of the fluid sample, and wherein the transporting occurs, at least in part, by sedimentation. Signal may be detected from the labeling agents of the complexes.

  10. Comparison of preprocessing methods and storage times for touch DNA samples

    PubMed Central

    Dong, Hui; Wang, Jing; Zhang, Tao; Ge, Jian-ye; Dong, Ying-qiang; Sun, Qi-fan; Liu, Chao; Li, Cai-xia

    2017-01-01

    Aim To select appropriate preprocessing methods for different substrates by comparing the effects of four different preprocessing methods on touch DNA samples and to determine the effect of various storage times on the results of touch DNA sample analysis. Method Hand touch DNA samples were used to investigate the detection and inspection results of DNA on different substrates. Four preprocessing methods, including the direct cutting method, stubbing procedure, double swab technique, and vacuum cleaner method, were used in this study. DNA was extracted from mock samples with four different preprocessing methods. The best preprocess protocol determined from the study was further used to compare performance after various storage times. DNA extracted from all samples was quantified and amplified using standard procedures. Results The amounts of DNA and the number of alleles detected on the porous substrates were greater than those on the non-porous substrates. The performances of the four preprocessing methods varied with different substrates. The direct cutting method displayed advantages for porous substrates, and the vacuum cleaner method was advantageous for non-porous substrates. No significant degradation trend was observed as the storage times increased. Conclusion Different substrates require the use of different preprocessing method in order to obtain the highest DNA amount and allele number from touch DNA samples. This study provides a theoretical basis for explorations of touch DNA samples and may be used as a reference when dealing with touch DNA samples in case work. PMID:28252870

  11. Sampling uncertainty evaluation for data acquisition board based on Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Ge, Leyi; Wang, Zhongyu

    2008-10-01

    Evaluating the data acquisition board sampling uncertainty is a difficult problem in the field of signal sampling. This paper analyzes the sources of dada acquisition board sampling uncertainty in the first, then introduces a simulation theory of dada acquisition board sampling uncertainty evaluation based on Monte Carlo method and puts forward a relation model of sampling uncertainty results, sampling numbers and simulation times. In the case of different sample numbers and different signal scopes, the author establishes a random sampling uncertainty evaluation program of a PCI-6024E data acquisition board to execute the simulation. The results of the proposed Monte Carlo simulation method are in a good agreement with the GUM ones, and the validities of Monte Carlo method are represented.

  12. Quantification of active infliximab in human serum with liquid chromatography-tandem mass spectrometry using a tumor necrosis factor alpha -based pre-analytical sample purification and a stable isotopic labeled infliximab bio-similar as internal standard: A target-based, sensitive and cost-effective method.

    PubMed

    El Amrani, Mohsin; van den Broek, Marcel P H; Göbel, Camiel; van Maarseveen, Erik M

    2016-07-08

    The therapeutic monoclonal antibody Infliximab (IFX) is a widely used drug for the treatment of several inflammatory autoimmune diseases. However, approximately 10% of patients develop anti-infliximab antibodies (ATIs) rendering the treatment ineffective. Early detection of underexposure to unbound IFX would result in a timely switch of therapy which could aid in the treatment of this disease. Streptavidin coated 96 well plates were used to capture biotinylated-tumor necrosis factor -alpha (b-TNF-α), which in turn was used to selectively extract the active form of IFX in human serum. After elution, IFX was digested using trypsin and one signature peptide was selected for subsequent analysis on liquid chromatography-tandem mass spectrometry (LC-MS/MS). The internal standard used was a stable isotopic labeled IFX bio-similar. The assay was successfully validated according to European Medicines Agency (EMA) guidelines and was found to be linear in a range of 0.5-20μg/mL (r(2)=0.994). Lower limit of quantification for the assay (<20% CV) was 0.5μg/mL, requiring only 2μL of sample. Cross-validation against enzyme-linked immunosorbent assay (ELISA) resulted in a high correlation between methods (r(2)=0.95 with a ρc=0.83) and the accuracy was in line with previously published results. In conclusion, a sensitive, robust and cost-effective method was developed for the bio-analysis of IFX with LC-MS/MS by means of a target-based pre-analytical sample purification. Moreover, low volume and costs of consumables per sample promote its feasibility in (pre)clinical studies and in therapeutic drug monitoring. This method should be considered as first choice due to its accuracy and multiple degree of selectivity.

  13. Evaluation of seven aquatic sampling methods for amphibians and other aquatic fauna

    USGS Publications Warehouse

    Gunzburger, M.S.

    2007-01-01

    To design effective and efficient research and monitoring programs researchers must have a thorough understanding of the capabilities and limitations of their sampling methods. Few direct comparative studies exist for aquatic sampling methods for amphibians. The objective of this study was to simultaneously employ seven aquatic sampling methods in 10 wetlands to compare amphibian species richness and number of individuals detected with each method. Four sampling methods allowed counts of individuals (metal dipnet, D-frame dipnet, box trap, crayfish trap), whereas the other three methods allowed detection of species (visual encounter, aural, and froglogger). Amphibian species richness was greatest with froglogger, box trap, and aural samples. For anuran species, the sampling methods by which each life stage was detected was related to relative length of larval and breeding periods and tadpole size. Detection probability of amphibians varied across sampling methods. Box trap sampling resulted in the most precise amphibian count, but the precision of all four count-based methods was low (coefficient of variation > 145 for all methods). The efficacy of the four count sampling methods at sampling fish and aquatic invertebrates was also analyzed because these predatory taxa are known to be important predictors of amphibian habitat distribution. Species richness and counts were similar for fish with the four methods, whereas invertebrate species richness and counts were greatest in box traps. An effective wetland amphibian monitoring program in the southeastern United States should include multiple sampling methods to obtain the most accurate assessment of species community composition at each site. The combined use of frogloggers, crayfish traps, and dipnets may be the most efficient and effective amphibian monitoring protocol. ?? 2007 Brill Academic Publishers.

  14. Quantitative Method of Measuring Metastatic Activity

    NASA Technical Reports Server (NTRS)

    Morrison, Dennis R. (Inventor)

    1999-01-01

    The metastatic potential of tumors can be evaluated by the quantitative detection of urokinase and DNA. The cell sample selected for examination is analyzed for the presence of high levels of urokinase and abnormal DNA using analytical flow cytometry and digital image analysis. Other factors such as membrane associated uroldnase, increased DNA synthesis rates and certain receptors can be used in the method for detection of potentially invasive tumors.

  15. Incorporating Writing into the Science Curriculum: A Sample Activity.

    ERIC Educational Resources Information Center

    Totten, Samuel; Tinnin, Claire

    1988-01-01

    Presents a lesson on introducing writing into the science curriculum by using an experiment to illustrate the detrimental effect of tobacco smoke on human lungs. Outlines the materials, procedures, a summary of the project, extension activities, and additional information about the writing process. Two handout sheets are included. (RT)

  16. Evaluation of micro-colorimetric lipid determination method with samples prepared using sonication and accelerated solvent extraction methods.

    PubMed

    Billa, Nanditha; Hubin-Barrows, Dylan; Lahren, Tylor; Burkhard, Lawrence P

    2014-02-01

    Two common laboratory extraction techniques were evaluated for routine use with the micro-colorimetric lipid determination method developed by Van Handel (1985) [2] and recently validated for small samples by Inouye and Lotufo (2006) [1]. With the accelerated solvent extraction method using chloroform:methanol solvent and the colorimetric lipid determination method, 28 of 30 samples had significant proportional bias (α=1%, determined using standard additions) and 1 of 30 samples had significant constant bias (α=1%, determined using Youden Blank measurements). With sonic extraction, 0 of 6 samples had significant proportional bias (α=1%) and 1 of 6 samples had significant constant bias (α=1%). These demonstrate that the accelerated solvent extraction method with chloroform:methanol solvent system creates an interference with the colorimetric assay method, and without accounting for the bias in the analysis, inaccurate measurements would be obtained.

  17. An inter-laboratory comparison of different analytical methods for the determination of monomethylmercury in various soil and sediment samples: A platform for method improvement.

    PubMed

    Kodamatani, Hitoshi; Balogh, Steven J; Nollet, Yabing H; Matsuyama, Akito; Fajon, Vesna; Horvat, Milena; Tomiyasu, Takashi

    2017-02-01

    An inter-laboratory study was conducted to compare results from different analytical methods for monomethylmercury (MeHg) concentrations in 17 soil and sediment samples. The samples were collected from mercury-contaminated areas, including Minamata Bay and Kagoshima Bay in Japan, the Idrija mercury mine in Slovenia, and an artisanal small-scale gold mining area in Indonesia. The Hg in these samples comes from several different sources: industrial waste from an acetaldehyde production facility, volcanic activity, Hg mining activity, and artisanal and small-scale gold mining activity (ASGM). MeHg concentrations in all the samples were measured in four separate laboratories, using three different determination methods: Kagoshima University (Japan), using high-performance liquid chromatography-chemiluminescence detection (HPLC-CL); National Institute for Minamata Disease (Japan), using gas chromatography-electron capture detection; and Metropolitan Council Environmental Services (USA) and Jozef Stefan Institute (Slovenia), both using alkylation-gas chromatography-atomic fluorescence spectrometry detection. The methods gave comparable MeHg results for most of the samples tested, but for some samples, the results exhibited significant variability depending on the method used. The HPLC-CL method performed poorly when applied to samples with elevated sulfur concentrations, producing MeHg concentrations that were much lower than those from the other methods. Additional analytical work demonstrated the elimination of this sulfur interference when the method was modified to bind sulfur prior to the analytical step by using Hg(2+) as a masking agent. These results demonstrate the value of laboratory intercomparison exercises in contributing to the improvement of analytical methods.

  18. Development of a sampling and analytical method for 2,2-dichloro-1,1,1-trifluoroethane in workplace air.

    PubMed

    Shin, Yong Chul; Yi, Gwang Yong; Kim, Yangho; Paik, Nam Won

    2002-01-01

    The use of 2,2-dichloro-1,1,1-trifluoroethane (compound number: HCFC-123) is growing in industry as a substitute for ozone-depleting chlorofluorocarbons (CFCs). Recently, liver-related illnesses have been reported from industries handling HCFC-123. However, information on worker exposure to the material is limited, and an acceptable sampling/analytical method is not available. The aim of this study was to develop a widely applicable sampling and analytical method to determine worker exposures to airborne HCFC-123 and to evaluate the performance of the method. A solid sorbent tube, containing two sections (400 mg in the front and 200 mg in the back) of activated coconut-shell charcoal was chosen for sampling airborne HCFC-123 vapor. The breakthrough volumes were 13.6 L at 3597 +/- 210.1 ppm (with a sampling airflow rate of 0.046 L/min) and 17.0 L at 1841 +/- 4.5 ppm (with sampling airflow rate of 0.046-0.050 L/min). Samples of HCFC-123 in the charcoal tube were stable for 7 days either at room temperature or in a refrigerator and a migration occurred within 14 days at room temperature. It is recommended that the HCFC-123 sample in activated charcoal tubes be stored either at room temperature or in a refrigerator and be analyzed within 7 days. The HCFC-123 in the charcoal tubes was desorbed into dichloromethane and analyzed using gas chromatography/ flame ionization detection. The limit of detection was 0.23 mg/sample, and the average desorption efficiency was 99.0%. The total coefficient of variation was 0.060, and the method accuracy was 16.6%. In conclusion, the performance of the sampling and analytical method developed for the determination of airborne HCFC-123 concentrations was acceptable to the NIOSH sampling and analytical criteria.

  19. A Novel Method of Failure Sample Selection for Electrical Systems Using Ant Colony Optimization

    PubMed Central

    Tian, Shulin; Yang, Chenglin; Liu, Cheng

    2016-01-01

    The influence of failure propagation is ignored in failure sample selection based on traditional testability demonstration experiment method. Traditional failure sample selection generally causes the omission of some failures during the selection and this phenomenon could lead to some fearful risks of usage because these failures will lead to serious propagation failures. This paper proposes a new failure sample selection method to solve the problem. First, the method uses a directed graph and ant colony optimization (ACO) to obtain a subsequent failure propagation set (SFPS) based on failure propagation model and then we propose a new failure sample selection method on the basis of the number of SFPS. Compared with traditional sampling plan, this method is able to improve the coverage of testing failure samples, increase the capacity of diagnosis, and decrease the risk of using. PMID:27738424

  20. Methods for using polypeptides having cellobiohydrolase activity

    DOEpatents

    Morant, Marc D; Harris, Paul

    2016-08-23

    The present invention relates to isolated polypeptides having cellobiohydrolase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  1. Practical method for extraction of PCR-quality DNA from environmental soil samples.

    PubMed

    Fitzpatrick, Kelly A; Kersh, Gilbert J; Massung, Robert F

    2010-07-01

    Methods for the extraction of PCR-quality DNA from environmental soil samples by using pairs of commercially available kits were evaluated. Coxiella burnetii DNA was detected in spiked soil samples at <1,000 genome equivalents per gram of soil and in 12 (16.4%) of 73 environmental soil samples.

  2. Study on Determination of Antimony in Environmental Samples by Neutron Activation Analysis

    NASA Astrophysics Data System (ADS)

    Martins, Tassiane Cristina Gomes; Saiki, Mitiko; Zahn, Guilherme Soares

    2011-08-01

    There is an increasing interest in the determination of antimony in environmental samples since this element is cumulative and potentially toxic at very low concentrations. Moreover, the quantification of antimony presents difficulties due to its low concentrations in the samples and to the interference problem in the analyses. In this study, neutron activation analysis procedure was established in order to obtain reliable results for Sb determination in environmental samples. For this study ten reference materials were analyzed. Aliquots of these materials and synthetic standard of Sb were irradiated at the IEA- R1 nuclear reactor under a thermal neutron flux of about 5×1012 n cm-2 s-1 for 8 or 16 hours. The induced gamma activities of 122Sb and 124Sb were measured using a hyperpure Ge detector. Antimony concentrations were calculated by comparative method and the uncertainties of the results were estimated using statistical counting errors of the sample and standard. Relative errors calculated demonstrated that the accuracy of the results depends on the Sb radioisotope measured and the decay time for counting.

  3. METHOD DEVELOPMENT FOR THE DETERMINATION OF FORMALDEHYDE IN SAMPLES OF ENVIRONMENTAL ORIGIN

    EPA Science Inventory

    An analytical method was developed for the determination of formaldehyde in samples of environmental origin. After a review of the current literature, five candidate methods involving chemical derivatization were chosen for evaluation. The five derivatization reagents studied wer...

  4. Substrate-zymography: a still worthwhile method for gelatinases analysis in biological samples.

    PubMed

    Ricci, Serena; D'Esposito, Vittoria; Oriente, Francesco; Formisano, Pietro; Di Carlo, Angelina

    2016-08-01

    Matrix metallo-proteinases (MMPs) are a family of zinc-dependent endopeptidases, capable of degrading all the molecular components of extracellular matrix. A class of MMPs is gelatinases which includes gelatinase A or MMP-2 (72 kDa) and gelatinase B or MMP-9 (92 kDa), which have been shown to play critical roles in pathophysiology of many human disease and, in particular, cancer progression. For these reasons they obtained a great interest as potential non-invasive biomarker in providing useful clinical information in cancer diagnosis and therapy. A sensitive and unexpensive method for analysis of gelatinases is the gelatine zymography, which allows to measure the relative amounts of active and inactive enzymes in body fluids and tissue extracts. The procedure involves the electrophoretic separation of proteins under denaturing but non reducing conditions through a polyacrylamide gel containing a synthetic substrate (gelatin). The aim of this mini-review has been to describe the general principles of gelatine zymography technique, underling the main advantages and disadvantages. Even though an improvement of this method is necessary for a better applicability in laboratory medicine, gelatine zymography represents the most convenient method to detect the activity of the different gelatinases from a wide range of biological samples.

  5. Global mean estimation using a self-organizing dual-zoning method for preferential sampling.

    PubMed

    Pan, Yuchun; Ren, Xuhong; Gao, Bingbo; Liu, Yu; Gao, YunBing; Hao, Xingyao; Chen, Ziyue

    2015-03-01

    Giving an appropriate weight to each sampling point is essential to global mean estimation. The objective of this paper was to develop a global mean estimation method with preferential samples. The procedure for this estimation method was to first zone the study area based on self-organizing dual-zoning method and then to estimate the mean according to stratified sampling method. In this method, spreading of points in both feature and geographical space is considered. The method is tested in a case study on the metal Mn concentrations in Jilin provinces of China. Six sample patterns are selected to estimate the global mean and compared with the global mean calculated by direct arithmetic mean method, polygon method, and cell method. The results show that the proposed method produces more accurate and stable mean estimates under different feature deviation index (FDI) values and sample sizes. The relative errors of the global mean calculated by the proposed method are from 0.14 to 1.47 % and they are the largest (4.83-8.84 %) by direct arithmetic mean method. At the same time, the mean results calculated by the other three methods are sensitive to the FDI values and sample sizes.

  6. Review of Analytes of Concern and Sample Methods for Closure of DOE High Level Waste Storage Tanks

    SciTech Connect

    Thomas, T.R.

    2002-05-06

    Sampling residual waste after tank cleaning and analysis for analytes of concern to support closure and cleaning targets of large underground tanks used for storage of legacy high level radioactive waste (HLW) at Department of Energy (DOE) sites has been underway since about 1995. The DOE Tanks Focus Area (TFA) has been working with DOE tank sites to develop new sampling plans, and sampling methods for assessment of residual waste inventories. This paper discusses regulatory analytes of concern, sampling plans, and sampling methods that support closure and cleaning target activities for large storage tanks at the Hanford Site, the Savannah River Site (SRS), the Idaho National Engineering and Environmental Laboratory (INEEL), and the West Valley Demonstration Project (WVDP).

  7. Review of Analytes of Concern and Sample Methods for Closure of DOE High Level Waste Storage Tanks

    SciTech Connect

    Thomas, Thomas Russell

    2002-08-01

    Sampling residual waste after tank cleaning and analysis for analytes of concern to support closure and cleaning targets of large underground tanks used for storage of legacy high level radioactive waste (HLW) at Department of Energy (DOE) sites has been underway since about 1995. The DOE Tanks Focus Area (TFA) has been working with DOE tank sites to develop new sampling plans, and sampling methods for assessment of residual waste inventories. This paper discusses regulatory analytes of concern, sampling plans, and sampling methods that support closure and cleaning target activities for large storage tanks at the Hanford Site, the Savannah River Site (SRS), the Idaho National Engineering and Environmental Laboratory (INEEL), and the West Valley Demonstration Project (WVDP).

  8. Systems and methods for separating particles and/or substances from a sample fluid

    DOEpatents

    Mariella, Jr., Raymond P.; Dougherty, George M.; Dzenitis, John M.; Miles, Robin R.; Clague, David S.

    2016-11-01

    Systems and methods for separating particles and/or toxins from a sample fluid. A method according to one embodiment comprises simultaneously passing a sample fluid and a buffer fluid through a chamber such that a fluidic interface is formed between the sample fluid and the buffer fluid as the fluids pass through the chamber, the sample fluid having particles of interest therein; applying a force to the fluids for urging the particles of interest to pass through the interface into the buffer fluid; and substantially separating the buffer fluid from the sample fluid.

  9. A standardized method for sampling and extraction methods for quantifying microplastics in beach sand.

    PubMed

    Besley, Aiken; Vijver, Martina G; Behrens, Paul; Bosker, Thijs

    2017-01-15

    Microplastics are ubiquitous in the environment, are frequently ingested by organisms, and may potentially cause harm. A range of studies have found significant levels of microplastics in beach sand. However, there is a considerable amount of methodological variability among these studies. Methodological variation currently limits comparisons as there is no standard procedure for sampling or extraction of microplastics. We identify key sampling and extraction procedures across the literature through a detailed review. We find that sampling depth, sampling location, number of repeat extractions, and settling times are the critical parameters of variation. Next, using a case-study we determine whether and to what extent these differences impact study outcomes. By investigating the common practices identified in the literature with the case-study, we provide a standard operating procedure for sampling and extracting microplastics from beach sand.

  10. Method for monitoring stack gases for uranium activity

    DOEpatents

    Beverly, Claude R.; Ernstberger, Harold G.

    1988-01-01

    A method for monitoring the stack gases of a purge cascade of a gaseous diffusion plant for uranium activity. A sample stream is taken from the stack gases and contacted with a volume of moisture-laden air for converting trace levels of uranium hexafluoride, if any, in the stack gases into particulate uranyl fluoride. A continuous strip of filter paper from a supply roll is passed through this sampling stream to intercept and gather any uranyl fluoride in the sampling stream. This filter paper is then passed by an alpha scintillation counting device where any radioactivity on the filter paper is sensed so as to provide a continuous monitoring of the gas stream for activity indicative of the uranium content in the stack gases.

  11. Method for monitoring stack gases for uranium activity

    DOEpatents

    Beverly, C.R.; Ernstberger, E.G.

    1985-07-03

    A method for monitoring the stack gases of a purge cascade of gaseous diffusion plant for uranium activity. A sample stream is taken from the stack gases and contacted with a volume of moisture-laden air for converting trace levels of uranium hexafluoride, if any, in the stack gases into particulate uranyl fluoride. A continuous strip of filter paper from a supply roll is passed through this sampling stream to intercept and gather any uranyl fluoride in the sampling stream. This filter paper is then passed by an alpha scintillation counting device where any radioactivity on the filter paper is sensed so as to provide a continuous monitoring of the gas stream for activity indicative of the uranium content in the stack gases. 1 fig.

  12. Accelerometer-Determined Physical Activity and Its Comparison with the International Physical Activity Questionnaire in a Sample of Nigerian Adults

    PubMed Central

    Oyeyemi, Adewale L.; Umar, Maimuna; Oguche, Friday; Aliyu, Salamatu U.; Oyeyemi, Adetoyeje Y.

    2014-01-01

    Introduction Accurate assessment of physical activity to identify current levels and changes within the population is dependent on the precision of the measurement tools. The aim of this study was to compare components of physical activity measured with an adapted version of the International Physical Activity Questionnaire (Hausa IPAQ-SF) and the accelerometer in a sample of Nigeria adults. Methods One hundred and forty-four participants (Mean age = 32.6±9.9 years, 40.3% women) in a cross-sectional study wore an accelerometer for seven consecutive days and completed the Hausa IPAQ-SF questionnaire on the eighth day. Total physical activity, time spent in moderate-to-vigorous activity (MVPA) and sedentary time assessed by Hausa IPAQ-SF and accelerometer were compared. The absolute and criterion- related validity of the Hausa IPAQ-SF was assessed by Bland-Altman analysis and Spearman Correlation Coefficients, respectively. Specificity and sensitivity were calculated to classify individuals according to the global standard guideline for sufficient physical activity. Results Compared with the accelerometer, higher time in MVPA and total physical activity were reported on the Hausa IPAQ-SF (p<0.001), while low to moderate correlations (Rs = 0.03–0.38) were found between the two methods. The 95% limits of agreement were wide between methods for total physical activity (−23019 to 20375 METmin.d−1) and sedentary time (−510 to 150 min.d−1). The sensitivity (76.2%) of Hausa IPAQ-SF to identify insufficiently active people was good, but its specificity (33.3%) to correctly classify sufficiently active people was low. Conclusions The Hausa IPAQ-SF overestimated components of physical activity among Nigerian adults, and demonstrated poor to moderate evidence of absolute and criterion validity. Further evaluation of IPAQ and other self-report physical activity instruments in other Africa populations could enhance accurate evaluation of physical activity data

  13. Evaluation of methods to assess physical activity

    NASA Astrophysics Data System (ADS)

    Leenders, Nicole Y. J. M.

    Epidemiological evidence has accumulated that demonstrates that the amount of physical activity-related energy expenditure during a week reduces the incidence of cardiovascular disease, diabetes, obesity, and all-cause mortality. To further understand the amount of daily physical activity and related energy expenditure that are necessary to maintain or improve the functional health status and quality of life, instruments that estimate total (TDEE) and physical activity-related energy expenditure (PAEE) under free-living conditions should be determined to be valid and reliable. Without evaluation of the various methods that estimate TDEE and PAEE with the doubly labeled water (DLW) method in females there will be eventual significant limitations on assessing the efficacy of physical activity interventions on health status in this population. A triaxial accelerometer (Tritrac-R3D, (TT)), an uniaxial (Computer Science and Applications Inc., (CSA)) activity monitor, a Yamax-Digiwalker-500sp°ler , (YX-stepcounter), by measuring heart rate responses (HR method) and a 7-d Physical Activity Recall questionnaire (7-d PAR) were compared with the "criterion method" of DLW during a 7-d period in female adults. The DLW-TDEE was underestimated on average 9, 11 and 15% using 7-d PAR, HR method and TT. The underestimation of DLW-PAEE by 7-d PAR was 21% compared to 47% and 67% for TT and YX-stepcounter. Approximately 56% of the variance in DLW-PAEE*kgsp{-1} is explained by the registration of body movement with accelerometry. A larger proportion of the variance in DLW-PAEE*kgsp{-1} was explained by jointly incorporating information from the vertical and horizontal movement measured with the CSA and Tritrac-R3D (rsp2 = 0.87). Although only a small amount of variance in DLW-PAEE*kgsp{-1} is explained by the number of steps taken per day, because of its low cost and ease of use, the Yamax-stepcounter is useful in studies promoting daily walking. Thus, studies involving the

  14. The impact of particle size selective sampling methods on occupational assessment of airborne beryllium particulates.

    PubMed

    Sleeth, Darrah K

    2013-05-01

    In 2010, the American Conference of Governmental Industrial Hygienists (ACGIH) formally changed its Threshold Limit Value (TLV) for beryllium from a 'total' particulate sample to an inhalable particulate sample. This change may have important implications for workplace air sampling of beryllium. A history of particle size-selective sampling methods, with a special focus on beryllium, will be provided. The current state of the science on inhalable sampling will also be presented, including a look to the future at what new methods or technology may be on the horizon. This includes new sampling criteria focused on particle deposition in the lung, proposed changes to the existing inhalable convention, as well as how the issues facing beryllium sampling may help drive other changes in sampling technology.

  15. Total nitrogen determination of various sample types: a comparison of the Hach, Kjeltec, and Kjeldahl methods.

    PubMed

    Watkins, K L; Veum, T L; Krause, G F

    1987-01-01

    Conventional Kjeldahl analysis with modifications, Kjeltec analysis with block digestion and semiautomated distillation, and the Hach method for determining nitrogen (N) were compared using a wide range of samples. Twenty different sample types were ground and mixed. Each sample type was divided into 5 subsamples which were analyzed for N by each of the 3 methods. In each sample type, differences (P less than 0.05) were detected among the 3 N determination methods in 5 of the 20 N sources analyzed. The mean N content over all 20 samples was higher with Kjeldahl analysis (P less than 0.05) than with Kjeltec, while Hach analysis produced intermediate results. Results also indicated that the Hach procedure had the greatest ability to detect differences in N content among sample types, being more sensitive than either other method (P less than 0.05).

  16. The Basket Method for Selecting Balanced Samples. Part II. Applications to Price Estimation.

    DTIC Science & Technology

    1981-12-01

    AD-AI12 949 CLEMSON UNIV SC OEPT OF MATHEMATICAL SCIENCES F/B 12/1 THE BASKET METHOD FOR SELECTING BALANCED SAMPLES. PART 11. APPL-ETC(U) DEC SI K T...1111󈧝 1.4 1.6 MICROCOPY RESOLUTION TEST CHARTNN’( 4~ THE BASKET METHOD FOR SELECTING BALANCED SAMPLES - PART II: APPLICATIONS TO PRICE ESTIMATION * K...for Selecting Balanced Samples Part I: Applications to Price Estimation AB9TRACT The "Basket Method" of sampling, a tool designed to achieve

  17. Rapid method for the determination of 226Ra in hydraulic fracturing wastewater samples

    DOE PAGES

    Maxwell, Sherrod L.; Culligan, Brian K.; Warren, Richard A.; ...

    2016-03-24

    A new method that rapidly preconcentrates and measures 226Ra from hydraulic fracturing wastewater samples was developed in the Savannah River Environmental Laboratory. The method improves the quality of 226Ra measurements using gamma spectrometry by providing up to 100x preconcentration of 226Ra from this difficult sample matrix, which contains very high levels of calcium, barium, strontium, magnesium and sodium. The high chemical yield, typically 80-90%, facilitates a low detection limit, important for lower level samples, and indicates method ruggedness. Ba-133 tracer is used to determine chemical yield and correct for geometry-related counting issues. The 226Ra sample preparation takes < 2 hours.

  18. A Method for Microalgae Proteomics Analysis Based on Modified Filter-Aided Sample Preparation.

    PubMed

    Li, Song; Cao, Xupeng; Wang, Yan; Zhu, Zhen; Zhang, Haowei; Xue, Song; Tian, Jing

    2017-04-11

    With the fast development of microalgal biofuel researches, the proteomics studies of microalgae increased quickly. A filter-aided sample preparation (FASP) method is widely used proteomics sample preparation method since 2009. Here, a method of microalgae proteomics analysis based on modified filter-aided sample preparation (mFASP) was described to meet the characteristics of microalgae cells and eliminate the error caused by over-alkylation. Using Chlamydomonas reinhardtii as the model, the prepared sample was tested by standard LC-MS/MS and compared with the previous reports. The results showed mFASP is suitable for most of occasions of microalgae proteomics studies.

  19. Purposeful Sampling for Qualitative Data Collection and Analysis in Mixed Method Implementation Research.

    PubMed

    Palinkas, Lawrence A; Horwitz, Sarah M; Green, Carla A; Wisdom, Jennifer P; Duan, Naihua; Hoagwood, Kimberly

    2015-09-01

    Purposeful sampling is widely used in qualitative research for the identification and selection of information-rich cases related to the phenomenon of interest. Although there are several different purposeful sampling strategies, criterion sampling appears to be used most commonly in implementation research. However, combining sampling strategies may be more appropriate to the aims of implementation research and more consistent with recent developments in quantitative methods. This paper reviews the principles and practice of purposeful sampling in implementation research, summarizes types and categories of purposeful sampling strategies and provides a set of recommendations for use of single strategy or multistage strategy designs, particularly for state implementation research.

  20. Optical method for the characterization of laterally-patterned samples in integrated circuits

    DOEpatents

    Maris, Humphrey J.

    2001-01-01

    Disclosed is a method for characterizing a sample having a structure disposed on or within the sample, comprising the steps of applying a first pulse of light to a surface of the sample for creating a propagating strain pulse in the sample, applying a second pulse of light to the surface so that the second pulse of light interacts with the propagating strain pulse in the sample, sensing from a reflection of the second pulse a change in optical response of the sample, and relating a time of occurrence of the change in optical response to at least one dimension of the structure.

  1. Optical method and system for the characterization of laterally-patterned samples in integrated circuits

    DOEpatents

    Maris, Humphrey J.

    2008-03-04

    Disclosed is a method for characterizing a sample having a structure disposed on or within the sample, comprising the steps of applying a first pulse of light to a surface of the sample for creating a propagating strain pulse in the sample, applying a second pulse of light to the surface so that the second pulse of light interacts with the propagating strain pulse in the sample, sensing from a reflection of the second pulse a change in optical response of the sample, and relating a time of occurrence of the change in optical response to at least one dimension of the structure.

  2. Quantitative method of determining beryllium or a compound thereof in a sample

    DOEpatents

    McCleskey, T. Mark; Ehler, Deborah S.; John, Kevin D.; Burrell, Anthony K.; Collis, Gavin E.; Minogue, Edel M.; Warner, Benjamin P.

    2006-10-31

    A method of determining beryllium or a beryllium compound thereof in a sample, includes providing a sample suspected of comprising beryllium or a compound thereof, extracting beryllium or a compound thereof from the sample by dissolving in a solution, adding a fluorescent indicator to the solution to thereby bind any beryllium or a compound thereof to the fluorescent indicator, and determining the presence or amount of any beryllium or a compound thereof in the sample by measuring fluorescence.

  3. Quantitative method of determining beryllium or a compound thereof in a sample

    SciTech Connect

    McCleskey, T. Mark; Ehler, Deborah S.; John, Kevin D.; Burrell, Anthony K.; Collis, Gavin E.; Minogue, Edel M.; Warner, Benjamin P.

    2010-08-24

    A method of determining beryllium or a beryllium compound thereof in a sample, includes providing a sample suspected of comprising beryllium or a compound thereof, extracting beryllium or a compound thereof from the sample by dissolving in a solution, adding a fluorescent indicator to the solution to thereby bind any beryllium or a compound thereof to the fluorescent indicator, and determining the presence or amount of any beryllium or a compound thereof in the sample by measuring fluorescence.

  4. Estimation of the sugar cane cultivated area from LANDSAT images using the two phase sampling method

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (Principal Investigator); Cappelletti, C. A.; Mendonca, F. J.; Lee, D. C. L.; Shimabukuro, Y. E.

    1982-01-01

    A two phase sampling method and the optimal sampling segment dimensions for the estimation of sugar cane cultivated area were developed. This technique employs visual interpretations of LANDSAT images and panchromatic aerial photographs considered as the ground truth. The estimates, as a mean value of 100 simulated samples, represent 99.3% of the true value with a CV of approximately 1%; the relative efficiency of the two phase design was 157% when compared with a one phase aerial photographs sample.

  5. 7 CFR 51.308 - Methods of sampling and calculation of percentages.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Grades of Apples Methods of Sampling and Calculation of Percentages § 51.308 Methods of sampling and... weigh ten pounds or less, or in any container where the minimum diameter of the smallest apple does not vary more than 1/2 inch from the minimum diameter of the largest apple, percentages shall be...

  6. 7 CFR 51.308 - Methods of sampling and calculation of percentages.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Grades of Apples Methods of Sampling and Calculation of Percentages § 51.308 Methods of sampling and... weigh ten pounds or less, or in any container where the minimum diameter of the smallest apple does not vary more than 1/2 inch from the minimum diameter of the largest apple, percentages shall be...

  7. A LITERATURE REVIEW OF WIPE SAMPLING METHODS FOR CHEMICAL WARFARE AGENTS AND TOXIC INDUSTRIAL CHEMICALS

    EPA Science Inventory

    Wipe sampling is an important technique for the estimation of contaminant deposition in buildings, homes, or outdoor surfaces as a source of possible human exposure. Numerous

    methods of wipe sampling exist, and each method has its own specification for the type of wipe, we...

  8. Evaluation of beef trim sampling methods for detection of Shiga toxin-producing Escherichia coli (STEC)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Presence of Shiga toxin-producing Escherichia coli (STEC) is a major concern in ground beef. Several methods for sampling beef trim prior to grinding are currently used in the beef industry. The purpose of this study was to determine the efficacy of the sampling methods for detecting STEC in beef ...

  9. THE INFLUENCE OF PHYSICAL FACTORS ON COMPARATIVE PERFORMANCE OF SAMPLING METHODS IN LARGE RIVERS

    EPA Science Inventory

    In 1999, we compared five existing benthic macroinvertebrate sampling methods used in boatable rivers. Each sampling protocol was performed at each of 60 sites distributed among four rivers in the Ohio River drainage basin. Initial comparison of methods using key macroinvertebr...

  10. Application of a Permethrin Immunosorbent Assay Method to Residential Soil and Dust Samples

    EPA Science Inventory

    A low-cost, high throughput bioanalytical screening method was developed for monitoring cis/trans-permethrin in dust and soil samples. The method consisted of a simple sample preparation procedure [sonication with dichloromethane followed by a solvent exchange into methanol:wate...

  11. Active music therapy and Parkinson's disease: methods.

    PubMed

    Pacchetti, C; Aglieri, R; Mancini, F; Martignoni, E; Nappi, G

    1998-01-01

    Music therapy (MT) is an unconventional, multisensorial therapy poorly assessed in medical care but widely used to different ends in a variety of settings. MT has two branches: active and passive. In active MT the utilisation of instruments is structured to correspond to all sensory organs so as to obtain suitable motor and emotional responses. We conducted a prospective study to evaluate the effects of MT in the neurorehabilitation of patients with Parkinson's Disease (PD), a common degenerative disorder involving movement and emotional impairment. Sixteen PD patients took part in 13 weekly sessions of MT each lasting 2 hours. At the beginning and at the end of the session, every 2 weeks, the patients were evaluated by a neurologist, who assessed PD severity with UPDRS, emotional functions with Happiness Measures (HM) and quality of life using the Parkinson's Disease Quality of Life Questionnaire (PDQL). After every session a significant improvement in motor function, particularly in relation to hypokinesia, was observed both in the overall and in the pre-post session evaluations. HM, UPDRS-ADL and PDQL changes confirmed an improving effect of MT on emotional functions, activities of daily living and quality of life. In conclusion, active MT, operating at a multisensorial level, stimulates motor, affective and behavioural functions. Finally, we propose active MT as new method to include in PD rehabilitation programmes. This article describes the methods adopted during MT sessions with PD patients.

  12. Non-uniform sampling knife-edge method for camera modulation transfer function measurement

    NASA Astrophysics Data System (ADS)

    Duan, Yaxuan; Xue, Xun; Chen, Yongquan; Tian, Liude; Zhao, Jianke; Gao, Limin

    2016-11-01

    Traditional slanted knife-edge method experiences large errors in the camera modulation transfer function (MTF) due to tilt angle error in the knife-edge resulting in non-uniform sampling of the edge spread function. In order to resolve this problem, a non -uniform sampling knife-edge method for camera MTF measurement is proposed. By applying a simple direct calculation of the Fourier transform of the derivative for the non-uniform sampling data, the camera super-sampled MTF results are obtained. Theoretical simulations for images with and without noise under different tilt angle errors are run using the proposed method. It is demonstrated that the MTF results are insensitive to tilt angle errors. To verify the accuracy of the proposed method, an experimental setup for camera MTF measurement is established. Measurement results show that the proposed method is superior to traditional methods, and improves the universality of the slanted knife-edge method for camera MTF measurement.

  13. Universal nucleic acids sample preparation method for cells, spores and their mixture

    DOEpatents

    Bavykin, Sergei [Darien, IL

    2011-01-18

    The present invention relates to a method for extracting nucleic acids from biological samples. More specifically the invention relates to a universal method for extracting nucleic acids from unidentified biological samples. An advantage of the presently invented method is its ability to effectively and efficiently extract nucleic acids from a variety of different cell types including but not limited to prokaryotic or eukaryotic cells and/or recalcitrant organisms (i.e. spores). Unlike prior art methods which are focused on extracting nucleic acids from vegetative cell or spores, the present invention effectively extracts nucleic acids from spores, multiple cell types or mixtures thereof using a single method. Important that the invented method has demonstrated an ability to extract nucleic acids from spores and vegetative bacterial cells with similar levels effectiveness. The invented method employs a multi-step protocol which erodes the cell structure of the biological sample, isolates, labels, fragments nucleic acids and purifies labeled samples from the excess of dye.

  14. COMPARISON OF SAMPLING METHODS FOR SEMI-VOLATILE ORGANIC CARBON (SVOC) ASSOCIATED WITH PM 2.5

    EPA Science Inventory

    This study evaluates the influence of denuder sampling methods and filter collection media on the measurement of semi-volatile organic carbon (SVOC) associated with PM2.5. Two types of collection media, charcoal (activated carbon) and XAD, were used both in diffusion denuders ...

  15. Preliminary field evaluation of EPA Method CTM-039 (PM2.5 Stack Sampling Method)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural operations are encountering difficulties complying with current air pollution regulations for particulate matter (PM). These regulations are based on the National Ambient Air Quality Standards which set maximum concentration limits for ambient air PM. Source sampling for compliance purp...

  16. Update on field evaluation of EPA Method CTM-039 (PM2.5 Stack Sampling Method)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural operations are encountering difficulties complying with current air pollution regulations for particulate matter (PM). These regulations are based on the National Ambient Air Quality Standards, which set maximum concentration limits for ambient air PM. Source sampling for compliance pur...

  17. [Establishment and assessment of QA/QC method for sampling and analysis of atmosphere background CO2].

    PubMed

    Liu, Li-xin; Zhou, Ling-xi; Xia, Ling-jun; Wang, Hong-yang; Fang, Shuang-xi

    2014-12-01

    To strengthen scientific management and sharing of greenhouse gas data obtained from atmospheric background stations in China, it is important to ensure the standardization of quality assurance and quality control method for background CO2 sampling and analysis. Based on the greenhouse gas sampling and observation experience of CMA, using portable sampling observation and WS-CRDS analysis technique as an example, the quality assurance measures for atmospheric CO,sampling and observation in the Waliguan station (Qinghai), the glass bottle quality assurance measures and the systematic quality control method during sample analysis, the correction method during data processing, as well as the data grading quality markers and data fitting interpolation method were systematically introduced. Finally, using this research method, the CO2 sampling and observation data at the atmospheric background stations in 3 typical regions were processed and the concentration variation characteristics were analyzed, indicating that this research method could well catch the influences of the regional and local environmental factors on the observation results, and reflect the characteristics of natural and human activities in an objective and accurate way.

  18. Specific activity and hazards of granite samples collected from the Eastern Desert of Egypt.

    PubMed

    Arafa, Wafaa

    2004-01-01

    Fifty granitic rock samples were collected from different plutons in the central part of the Eastern Desert of Egypt and were analyzed for specific concentrations of (238)U, (232)Th and (40)K radionuclei. The measurements were carried out using a high performance and stability Nomad Plus spectroscopy system attached to a 1.7 keV (FWHM) HPGe detector. The spectra were analyzed using the direct gamma counting comparison method as well as the traditional absolute efficiency curve method. The highest average value of (238)U concentration (1184 Bq kg(-1)) was observed at EI Misikat region whereas the highest average values of (40)K and (232)Th concentration (2301.8 and 162.5 Bq kg(-1) respectively), were detected at Gabal Homret Waggat area. The radium equivalent activity (Ra(eq)), the absorbed dose rate (D), the external hazard index (H(ex)) and the annual gonadal dose equivalent were also calculated and compared to the international recommended values. Radon exhalation rate from the rock samples were measured using the activated charcoal canister method. The average value of radon exhalation varies from 0.052 to 0.69 Bq m(-2) h(-1) and depends on the specific concentration of uranium.

  19. Neutron activation determination of iridium, gold, platinum, and silver in geologic samples

    USGS Publications Warehouse

    Millard, H.T.

    1987-01-01

    Low-level methods for the determination of iridium and other noble metals have become increasingly important in recent years due to interest in locating abundance anomalies associated with the Cretaceous and Tertiary (K-T) boundary. Typical iridium anomalies are in the range of 1 to 100 ??g/kg (ppb). Thus methods with detection limits near 0.1 ??g/kg should be adequate to detect K-T boundary anomalies. Radiochemical neutron activation analysis methods continue to be required although instrumental neutron activation analysis techniques employing elaborate gamma-counters are under development. In the procedure developed in this study samples irradiated in the epithermal neutron facility of the U. S. Geological Survey TRIGA Reactor (Denver, Colorado) are treated with a mini-fire assay technique. The iridium, gold, and silver are collected in a 1-gram metallic lead button. Primary contaminants at this stage are arsenic and antimony. These can be removed by heating the button with a mixture of sodium perioxide and sodium hydroxide. The resulting 0.2-gram lead bead is counted in a Compton suppression spectrometer. Carrier yields are determined by reirradiation of the lead beads. This procedure has been applied to the U.S.G.S. Standard Rock PCC-1 and samples from K-T boundary sites in the Western Interior of North America. ?? 1987 Akade??miai Kiado??.

  20. Comparability among four invertebrate sampling methods, Fountain Creek Basin, Colorado, 2010-2012

    USGS Publications Warehouse

    Zuellig, Robert E.; Bruce, James F.; Stogner, Robert W.; Brown, Krystal D.

    2014-01-01

    The U.S. Geological Survey, in cooperation with Colorado Springs City Engineering and Colorado Springs Utilities, designed a study to determine if sampling method and sample timing resulted in comparable samples and assessments of biological condition. To accomplish this task, annual invertebrate samples were collected concurrently using four sampling methods at 15 U.S. Geological Survey streamflow gages in the Fountain Creek basin from 2010 to 2012. Collectively, the four methods are used by local (U.S. Geological Survey cooperative monitoring program) and State monitoring programs (Colorado Department of Public Health and Environment) in the Fountain Creek basin to produce two distinct sample types for each program that target single-and multiple-habitats. This study found distinguishable differences between single-and multi-habitat sample types using both community similarities and multi-metric index values, while methods from each program within sample type were comparable. This indicates that the Colorado Department of Public Health and Environment methods were compatible with the cooperative monitoring program methods within multi-and single-habitat sample types. Comparisons between September and October samples found distinguishable differences based on community similarities for both sample types, whereas only differences were found for single-habitat samples when multi-metric index values were considered. At one site, differences between September and October index values from single-habitat samples resulted in opposing assessments of biological condition. Direct application of the results to inform the revision of the existing Fountain Creek basin U.S. Geological Survey cooperative monitoring program are discussed.

  1. Transition Path Sampling Method and Its Application in Argon Phase Transition

    NASA Astrophysics Data System (ADS)

    Li, Bingxi

    Rare events during both physical and chemical transitions are of great significance to under- stand the evolution of systems from one stable state to another. Solid-solid phase transition is a fundamental problem in this field and a lot of experimental and theoretical efforts have been made into tackling it. However Molecular Dynamics simulation in this field encounters the problem that these transitions occur too rarely to be observed within current simulations. Thus the Transition Path Sampling (TPS) method is designed to tackle this issue. The phase transition between face centered cubic (fcc) and hexagonal close packed (hcp) phases in argon solid at 40K is investigated with TPS method. TPS is a rare event sampling methodology, which combine Molecular Dynamics and Monte Carlo. Molecular Dynamics is used to generate the whole trajectory from an assigned starting point, based on the time evolution of the system. Monte Carlo is applied to select a structure from the known phase transition trajectories as the starting point. This is an importance sampling process and the acceptance probability for starting point selection depends on its equilibrium probability in the ensemble of interest. With TPS method, the sampling of trajectories can be efficiently performed in the phase transition trajectories ensemble. The sampling process will yield energetically favorable trajectories. A phase transition trajectory is required to initialize the Molecular Dynamics Transition Path Sampling process. This trajectory can be generated with Variable Cell Nudged Elastic Band (VCNEB) method, which determines Ar fcc to hcp transition at 0K. The configuration of transition state in VCNEB trajectory is selected as the initial state to start TPS calculation. An atomistic description of the mechanism of the fcc-to- hcp transformation in solid argon is then obtained from Molecular Dynamics transition path sampling simulations. We show that the transition barrier at 40 K under ambient

  2. Phosphatase activity in Antarctica soil samples as a biosignature of extant life

    NASA Astrophysics Data System (ADS)

    Sato, Shuji; Itoh, Yuki; Takano, Yoshinori; Fukui, Manabu; Kaneko, Takeo; Kobayashi, Kensei

    Microbial activities have been detected in such extreme terrestrial environments as deep lithosphere, a submarine hydrothermal systems, stratosphere, and Antarctica. Microorganisms have adapted to such harsh environments by evolving their biomolecules. Some of these biomolecules such as enzymes might have different characteristics from those of organisms in ordinary environments. Many biosignatures (or biomarkers) have been proposed to detect microbial activities in such extreme environments. A number of techniques are proposed to evaluate biological activities in extreme environments including cultivation methods, assay of metabolism, and analysis of bioorganic compounds like amino acids and DNA. Enzyme activities are useful signature of extant life in extreme environments. Among many enzymes, phosphatase could be a good indicator of biological activities, since phosphate esters are essential for all the living terrestrial organisms. In addition, alkaline phosphatase is known as a typical zinc-containing metalloenzyme and quite stable in environments. We analyzed phosphatase activities in Antarctica soil samples to see whether they can be used as biosignatures for extant life. In addition, we characterized phosphatases extracted from the Antarctica soil samples, and compared with those obtained from other types of environments. Antarctica surface environments are quite severe environments for life since it is extremely cold and dry and exposed to strong UV and cosmic rays. We tried to evaluate biological activities in Antarctica by measuring phosphatase activities. Surface soil samples are obtained at the Sites 1-8 near Showa Base in Antarctica during the 47th Japan Antarctic exploration mission in 2005-6. Activities of acid phosphatase (ACP) and alkaline phosphatase (ALP) are measured spectrophotometrically after mixing the powdered sample and p-nitrophenyl phosphate solution (pH 6.5 for ACP, pH 8.0 for ALP). ALP was characterized after extraction from soils with

  3. Application of ATP-based bioluminescence for bioaerosol quantification: effect of sampling method.

    PubMed

    Han, Taewon; Wren, Melody; DuBois, Kelsey; Therkorn, Jennifer; Mainelis, Gediminas

    2015-12-01

    An adenosine triphosphate (ATP)-based bioluminescence has potential to offer a quick and affordable method for quantifying bioaerosol samples. Here we report on our investigation into how different bioaerosol aerosolization parameters and sampling methods affect bioluminescence output per bacterium, and implications of that effect for bioaerosol research. Bacillus atrophaeus and Pseudomonas fluorescens bacteria were aerosolized by using a Collison nebulizer (BGI Inc., Waltham, MA) with a glass or polycarbonate jar and then collected for 15 and 60 min with: (1) Button Aerosol Sampler (SKC Inc., Eighty Four, PA) with polycarbonate, PTFE, and cellulose nitrate filters, (2) BioSampler (SKC Inc.) with 5 and 20 mL of collection liquid, and (3) our newly developed Electrostatic Precipitator with Superhydrophobic Surface (EPSS). For all aerosolization and sampling parameters we compared the ATP bioluminescence output per bacterium relative to that before aerosolization and sampling. In addition, we also determined the ATP reagent storage and preparation conditions that that do not affect the bioluminescence signal intensity. Our results show that aerosolization by a Collison nebulizer with a polycarbonate jar yields higher bioluminescence output per bacterium compared to the glass jar. Interestingly enough, the bioluminescence output by P. fluorescens increased substantially after its aerosolization compared to the fresh liquid suspension. For both test microorganisms, the bioluminescence intensity per bacterium after sampling was significantly lower than that before sampling suggesting negative effect of sampling stress on bioluminescence output. The decrease in bioluminescence intensity was more pronounces for longer sampling times and significantly and substantially depended on the sampling method. Among the investigated method, the EPSS was the least injurious for both microorganisms and sampling times. While the ATP-based bioluminescence offers a quick bioaerosol

  4. Application of ATP-based bioluminescence for bioaerosol quantification: effect of sampling method

    PubMed Central

    Han, Taewon; Wren, Melody; DuBois, Kelsey; Therkorn, Jennifer; Mainelis, Gediminas

    2015-01-01

    An adenosine triphosphate (ATP)-based bioluminescence has potential to offer a quick and affordable method for quantifying bioaerosol samples. Here we report on our investigation into how different bioaerosol aerosolization parameters and sampling methods affect bioluminescence output per bacterium, and implications of that effect for bioaerosol research. Bacillus atrophaeus and Pseudomonas fluorescens bacteria were aerosolized by using a Collison nebulizer (BGI Inc., Waltham, MA) with a glass or polycarbonate jar and then collected for 15 and 60 min with: (1) Button Aerosol Sampler (SKC Inc., Eighty Four, PA) with polycarbonate, PTFE, and cellulose nitrate filters, (2) BioSampler (SKC Inc.) with 5 and 20 mL of collection liquid, and (3) our newly developed Electrostatic Precipitator with Superhydrophobic Surface (EPSS). For all aerosolization and sampling parameters we compared the ATP bioluminescence output per bacterium relative to that before aerosolization and sampling. In addition, we also determined the ATP reagent storage and preparation conditions that that do not affect the bioluminescence signal intensity. Our results show that aerosolization by a Collison nebulizer with a polycarbonate jar yields higher bioluminescence output per bacterium compared to the glass jar. Interestingly enough, the bioluminescence output by P. fluorescens increased substantially after its aerosolization compared to the fresh liquid suspension. For both test microorganisms, the bioluminescence intensity per bacterium after sampling was significantly lower than that before sampling suggesting negative effect of sampling stress on bioluminescence output. The decrease in bioluminescence intensity was more pronounces for longer sampling times and significantly and substantially depended on the sampling method. Among the investigated method, the EPSS was the least injurious for both microorganisms and sampling times. While the ATP-based bioluminescence offers a quick bioaerosol

  5. [Bioluminescent method of determining antiprotease activity].

    PubMed

    Gitel'zon, I I; Rykov, S A; Kratasiuk, G A; Petushkov, V N; Shvetskiĭ, A G

    1985-11-01

    A method for antiprotease activity measurement based on the use of luminous bacteria luciferase as protein substrate of proteases is suggested. Antiprotease is incubated with protease for 1 to 2 min at 30 degrees C and then it is added to the reaction mixture containing luciferase, NADH: FMN-oxidoreductase and their substrates--myristic aldehyde, FMN and NADH. Biofluorescence is measured in a temperature-controlled cuvette for 1 min. The total time of the measurement is 3 min. The method can be applied both in fine biochemical assays and in medical rapid diagnosis.

  6. Cytotoxic Activity of Six Samples of Brazilian Propolis on Sea Urchin (Lytechinus variegatus) Eggs

    PubMed Central

    Fernandes-Silva, C. C.; Freitas, J. C.; Salatino, A.; Salatino, M. L. F.

    2013-01-01

    The cytotoxic activities of extracts of four samples of propolis from the state of Minas Gerais (Southeast Brazil) and two from the state of Paraná (South Brazil) were evaluated using sea urchin (Lytechinus variegatus) eggs. Cytotoxic activity was observed, characterized mainly by the inhibition of the first cleavage of newly fertilized eggs. Methanol extracts at 32 µg mL−1 of all samples were highly active (97–100%). Extracts were also prepared by successive treatments of the samples with hexane, chloroform, ethyl acetate, and methanol. High activity was observed using the ethyl acetate fractions of all samples, but hexane and chloroform fractions of some samples also had high activity. Based on the chemical composition of the extracts and fractions (published previously), it is hypothesized that the cytotoxic activities observed are due mainly to artepillin C, p-coumaric acid, and kaempferide. The results suggest that caffeoylquinic acids have no cytotoxic activity in sea urchin eggs. PMID:23662146

  7. Method to produce catalytically active nanocomposite coatings

    DOEpatents

    Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

    2016-02-09

    A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

  8. Method for photon activation positron annihilation analysis

    DOEpatents

    Akers, Douglas W.

    2006-06-06

    A non-destructive testing method comprises providing a specimen having at least one positron emitter therein; determining a threshold energy for activating the positron emitter; and determining whether a half-life of the positron emitter is less than a selected half-life. If the half-life of the positron emitter is greater than or equal to the selected half-life, then activating the positron emitter by bombarding the specimen with photons having energies greater than the threshold energy and detecting gamma rays produced by annihilation of positrons in the specimen. If the half-life of the positron emitter is less then the selected half-life, then alternately activating the positron emitter by bombarding the specimen with photons having energies greater then the threshold energy and detecting gamma rays produced by positron annihilation within the specimen.

  9. Electrodeposition as an alternate method for preparation of environmental samples for iodide by AMS

    SciTech Connect

    Adamic, M. L.; Lister, T. E.; Dufek, E. J.; Jenson, D. D.; Olson, J. E.; Vockenhuber, C.; Watrous, M. G.

    2015-03-25

    This paper presents an evaluation of an alternate method for preparing environmental samples for 129I analysis by accelerator mass spectrometry (AMS) at Idaho National Laboratory. The optimal sample preparation method is characterized by ease of preparation, capability of processing very small quantities of iodide, and ease of loading into a cathode. Electrodeposition of iodide on a silver wire was evaluated using these criteria. This study indicates that the electrochemically-formed silver iodide deposits produce ion currents similar to those from precipitated silver iodide for the same sample mass. Furthermore, precipitated silver iodide samples are usually mixed with niobium or silver powder prior to loading in a cathode. Using electrodeposition, the silver is already mixed with the sample and can simply be picked up with tweezers, placed in the sample die, and pressed into a cathode. The major advantage of this method is that the silver wire/electrodeposited silver iodide is much easier to load into a cathode.

  10. Method validation and uncertainty evaluation of organically bound tritium analysis in environmental sample.

    PubMed

    Huang, Yan-Jun; Zeng, Fan; Zhang, Bing; Chen, Chao-Feng; Qin, Hong-Juan; Wu, Lian-Sheng; Guo, Gui-Yin; Yang, Li-Tao; Shang-Guan, Zhi-Hong

    2014-08-01

    The analytical method for organically bound tritium (OBT) was developed in our laboratory. The optimized operating conditions and parameters were established for sample drying, special combustion, distillation, and measurement on a liquid scintillation spectrometer (LSC). Selected types of OBT samples such as rice, corn, rapeseed, fresh lettuce and pork were analyzed for method validation of recovery rate reproducibility, the minimum detection concentration, and the uncertainty for typical low level environmental sample was evaluated. The combustion water recovery rate of different dried environmental sample was kept at about 80%, the minimum detection concentration of OBT ranged from 0.61 to 0.89 Bq/kg (dry weight), depending on the hydrogen content. It showed that this method is suitable for OBT analysis of environmental sample with stable recovery rate, and the combustion water yield of a sample with weight about 40 g would provide sufficient quantity for measurement on LSC.

  11. Activity of titania and zeolite samples dosed with triethylamine

    SciTech Connect

    Baker, Caitlin; Gole, James L.; Brauer, Jonathan; Graham, Samuel; Hu, Jianzhi; Kenvin, Jeff; D'Amico, Andrew D.; White, Mark G.

    2016-01-01

    Certain properties of titania and the ammonium- and proton-form of Y zeolites (silica/alumina ratio of 5.2) were explored before and after treatment by triethylamine (TEA). The effect of the triethylamine upon the physical and chemical properties of both titania and the zeolite were characterized by physical and chemical adsorption methods. BET surface area data showed enhanced surface area of the TEA-treated nanotitania over the untreated nanotitania whereas the TEA-treated zeolite showed a considerable decrease in surface area compared to the untreated zeolite. TPD of the TEA-treated Y zeolite showed that weakly adsorbed TEA left the surface between 150 and 300 oC; strongly adsorbed TEA decomposed to ethylene and ammonia at higher temperatures. XPS, IR, and Raman spectroscopies, powder XRD, and 27Al MAS-NMR spectroscopy were used to further characterize the changes introduced by in-situ nitridation. Pre-adsorbed triethylamine decorated acid sites so as to neutralize these sites for the reaction of methanol to dimethylether. Carbon monoxide and ormaldehyde, products of the methanol probe reaction, were observed-- suggesting that basic sites are present in this treated zeolite and titania.

  12. A new enrichment method for isolation of Bacillus thuringiensis from diverse sample types.

    PubMed

    Patel, Ketan D; Bhanshali, Forum C; Chaudhary, Avani V; Ingle, Sanjay S

    2013-05-01

    New or more efficient methodologies having different principles are needed, as one method could not be suitable for isolation of organisms from samples of diverse types and from various environments. In present investigation, growth kinetics study revealed a higher germination rate, a higher growth rate, and maximum sporulation of Bacillus thuringiensis (Bt) compared to other Bacillus species. Considering these facts, a simple and efficient enrichment method was devised which allowed propagation of spores and vegetative cells of Bt and thereby increased Bt cell population proportionately. The new enrichment method yielded Bt from 44 out of 58 samples. Contrarily, Bt was isolated only from 16 and 18 samples by sodium acetate selection and dry heat pretreatment methods, respectively. Moreover, the percentages of Bt colonies isolated by the enrichment method were higher comparatively. Vegetative whole cell protein profile analysis indicated isolation of diverse population of Bt from various samples. Bt strains isolated by the enrichment method represented novel serovars and possibly new cry2 gene.

  13. A modified method for estimation of chemical oxygen demand for samples having high suspended solids.

    PubMed

    Yadvika; Yadav, Asheesh Kumar; Sreekrishnan, T R; Satya, Santosh; Kohli, Sangeeta

    2006-03-01

    Determination of chemical oxygen demand (COD) of samples having high suspended solids concentration such as cattle dung slurry with open reflux method of APHA-AWWA-WPCF did not give consistent results. This study presents a modification of the open reflux method (APHA-AWWA-WPCF) to make it suitable for samples with high percentage of suspended solids. The new method is based on a different technique of sample preparation, modified quantities of reagents and higher reflux time as compared to the existing open reflux method. For samples having solids contents of 14.0 g/l or higher, the modified method was found to give higher value of COD with much higher consistency and accuracy as compared to the existing open reflux method.

  14. Melting Temperature Mapping Method: A Novel Method for Rapid Identification of Unknown Pathogenic Microorganisms within Three Hours of Sample Collection.

    PubMed

    Niimi, Hideki; Ueno, Tomohiro; Hayashi, Shirou; Abe, Akihito; Tsurue, Takahiro; Mori, Masashi; Tabata, Homare; Minami, Hiroshi; Goto, Michihiko; Akiyama, Makoto; Yamamoto, Yoshihiro; Saito, Shigeru; Kitajima, Isao

    2015-07-28

    Acquiring the earliest possible identification of pathogenic microorganisms is critical for selecting the appropriate antimicrobial therapy in infected patients. We herein report the novel "melting temperature (Tm) mapping method" for rapidly identifying the dominant bacteria in a clinical sample from sterile sites. Employing only seven primer sets, more than 100 bacterial species can be identified. In particular, using the Difference Value, it is possible to identify samples suitable for Tm mapping identification. Moreover, this method can be used to rapidly diagnose the absence of bacteria in clinical samples. We tested the Tm mapping method using 200 whole blood samples obtained from patients with suspected sepsis, 85% (171/200) of which matched the culture results based on the detection level. A total of 130 samples were negative according to the Tm mapping method, 98% (128/130) of which were also negative based on the culture method. Meanwhile, 70 samples were positive according to the Tm mapping method, and of the 59 suitable for identification, 100% (59/59) exhibited a "match" or "broad match" with the culture or sequencing results. These findings were obtained within three hours of whole blood collection. The Tm mapping method is therefore useful for identifying infectious diseases requiring prompt treatment.

  15. Guidance for characterizing explosives contaminated soils: Sampling and selecting on-site analytical methods

    SciTech Connect

    Crockett, A.B.; Craig, H.D.; Jenkins, T.F.; Sisk, W.E.

    1996-09-01

    A large number of defense-related sites are contaminated with elevated levels of secondary explosives. Levels of contamination range from barely detectable to levels above 10% that need special handling due to the detonation potential. Characterization of explosives-contaminated sites is particularly difficult due to the very heterogeneous distribution of contamination in the environment and within samples. To improve site characterization, several options exist including collecting more samples, providing on-site analytical data to help direct the investigation, compositing samples, improving homogenization of samples, and extracting larger samples. On-site analytical methods are essential to more economical and improved characterization. On-site methods might suffer in terms of precision and accuracy, but this is more than offset by the increased number of samples that can be run. While verification using a standard analytical procedure should be part of any quality assurance program, reducing the number of samples analyzed by the more expensive methods can result in significantly reduced costs. Often 70 to 90% of the soil samples analyzed during an explosives site investigation do not contain detectable levels of contamination. Two basic types of on-site analytical methods are in wide use for explosives in soil, calorimetric and immunoassay. Calorimetric methods generally detect broad classes of compounds such as nitroaromatics or nitramines, while immunoassay methods are more compound specific. Since TNT or RDX is usually present in explosive-contaminated soils, the use of procedures designed to detect only these or similar compounds can be very effective.

  16. A bone sample cleaning method using trypsin for the isolation of DNA.

    PubMed

    Li, Richard; Liriano, Lidissy

    2011-11-01

    Cleaning the surface of bone samples is a necessary step to remove contaminants prior to isolating DNA for forensic DNA analysis. In this study, a simple trypsin method for cleaning bone samples prior to DNA isolation was developed. Cleaning the surface of human bone samples was achieved by the application of trypsin solution. Light microscopy and scanning electron microscopy results indicated that trypsin treatment was effective in removing the outer surface of bone samples. The yield of DNA isolated from trypsin-treated bone samples was sufficient for subsequent short tandem repeat (STR) analysis. STR analysis revealed no adverse effect on the DNA profile after the trypsin treatment. The data suggest that this trypsin method can potentially be an alternative cleaning method to mechanical cleaning methods.

  17. Comparison of individual and pooled sampling methods for detecting bacterial pathogens of fish

    USGS Publications Warehouse

    Mumford, Sonia; Patterson, Chris; Evered, J.; Brunson, Ray; Levine, J.; Winton, J.

    2005-01-01

    Examination of finfish populations for viral and bacterial pathogens is an important component of fish disease control programs worldwide. Two methods are commonly used for collecting tissue samples for bacteriological culture, the currently accepted standards for detection of bacterial fish pathogens. The method specified in the Office International des Epizooties Manual of Diagnostic Tests for Aquatic Animals permits combining renal and splenic tissues from as many as 5 fish into pooled samples. The American Fisheries Society (AFS) Blue Book/US Fish and Wildlife Service (USFWS) Inspection Manual specifies the use of a bacteriological loop for collecting samples from the kidney of individual fish. An alternative would be to more fully utilize the pooled samples taken for virology. If implemented, this approach would provide substantial savings in labor and materials. To compare the relative performance of the AFS/USFWS method and this alternative approach, cultures of Yersinia ruckeri were used to establish low-level infections in groups of rainbow trout (Oncorhynchus mykiss) that were sampled by both methods. Yersinia ruckeri was cultured from 22 of 37 groups by at least 1 method. The loop method yielded 18 positive groups, with 1 group positive in the loop samples but negative in the pooled samples. The pooled samples produced 21 positive groups, with 4 groups positive in the pooled samples but negative in the loop samples. There was statistically significant agreement (Spearman coefficient 0.80, P < 0.001) in the relative ability of the 2 sampling methods to permit detection of low-level bacterial infections of rainbow trout.

  18. Determination of ATP-activity as a useful tool for monitoring microbial load in aqueous humidifier samples.

    PubMed

    Liebers, Verena; Bachmann, Dieter; Franke, Gabriele; Freundt, Susanne; Stubel, Heike; Düser, Maria; Kendzia, Benjamin; Böckler, Margret; Brüning, Thomas; Raulf, Monika

    2015-03-01

    Air humidifier water tanks are potential sources of microbial contaminants. Aerosolization of these contaminants is associated with the development of airway and lung diseases; therefore, implementation of preventive strategies including monitoring of the microbial contamination is recommended. So far, culture-based methods that include measuring colony forming units (CFU) are widely used to monitor microbial load. However, these methods are time consuming and have considerable drawbacks. As a result, alternative methods are needed which provide not only clear and accurate results concerning microbial load in water samples, but are also rapid and easy to use in the field. This paper reports on a rapid test for ATP quantification as an alternative method for microbial monitoring, including its implementation, validation and application in the field. For this purpose, 186 water samples were characterized with different methods, which included ATP analysis, culture-based methods, endotoxin activity (common and rapid test), pyrogenic activity and number of particles. Half of the samples was measured directly in the field and the other half one day later in the laboratory. The results of both tests are highly correlated. Furthermore, to check how representative the result from one sample of a water source is, a second sample of the same water tank were collected and measured. Bioluminescence results of the undiluted samples covered a range between 20 and 25,000 relative light units (RLU) and correlated with the results obtained using the other methods. The highest correlation was found between bioluminescence and endotoxin activity (rs=0.79) as well as pyrogenic activity (rs=0.75). Overall, the results of this study indicate that ATP measurement using bioluminescence is a suitable tool to obtain rapid, reproducible and sensitive information on the microbial load of water samples, and is suitable to use in the field. However, to use ATP measurement as an indicator of

  19. Quality assurance guidance for field sampling and measurement assessment plates in support of EM environmental sampling and analysis activities

    SciTech Connect

    Not Available

    1994-05-01

    This document is one of several guidance documents developed by the US Department of Energy (DOE) Office of Environmental Restoration and Waste Management (EM). These documents support the EM Analytical Services Program (ASP) and are based on applicable regulatory requirements and DOE Orders. They address requirements in DOE Orders by providing guidance that pertains specifically to environmental restoration and waste management sampling and analysis activities. DOE 5700.6C Quality Assurance (QA) defines policy and requirements to establish QA programs ensuring that risks and environmental impacts are minimized and that safety, reliability, and performance are maximized. This is accomplished through the application of effective management systems commensurate with the risks imposed by the facility and the project. Every organization supporting EM`s environmental sampling and analysis activities must develop and document a QA program. Management of each organization is responsible for appropriate QA program implementation, assessment, and improvement. The collection of credible and cost-effective environmental data is critical to the long-term success of remedial and waste management actions performed at DOE facilities. Only well established and management supported assessment programs within each EM-support organization will enable DOE to demonstrate data quality. The purpose of this series of documents is to offer specific guidance for establishing an effective assessment program for EM`s environmental sampling and analysis (ESA) activities.

  20. An effective method based on dynamic sampling for data assimilation in a global wave model

    NASA Astrophysics Data System (ADS)

    Sun, Meng; Yin, Xunqiang; Yang, Yongzeng; Wu, Kejian

    2017-01-01

    The ensemble Kalman filter (EnKF) performs well because that the covariance of background error is varying along time. It provides a dynamic estimate of background error and represents the reasonable statistic characters of background error. However, high computational cost due to model ensemble in EnKF is employed. In this study, two methods referred as static and dynamic sampling methods are proposed to obtain a good performance and reduce the computation cost. Ensemble adjustment Kalman filter (EAKF) method is used in a global surface wave model to examine the performance of EnKF. The 24-h interval difference of simulated significant wave height (SWH) within 1 year is used to compose the static samples for ensemble errors, and these errors are used to construct the ensemble states at each time the observations are available. And then, the same method of updating the model states in the EAKF is applied for the ensemble states constructed by a static sampling method. The dynamic sampling method employs a similar method to construct the ensemble states, but the period of the simulated SWH is changing with time. Here, 7 days before and after the observation time is used as this period. To examine the performance of three schemes, EAKF, static, or dynamic sampling method, observations from satellite Jason-2 in 2014 are assimilated into a global wave model, and observations from satellite Saral are used for validation. The results indicate that the EAKF performs best, while the static sampling method is relatively worse. The dynamic sampling method improves an assimilation effect dramatically compared to the static sampling method, and its overall performance is closed to the EAKF. In low latitudes, the dynamic sampling method has a slight advantage over the EAKF. In the dynamic or static sampling methods, only one wave model is required to run and their computational cost is reduced sharply. According to the performance of these three methods, the dynamic sampling

  1. RAPID FUSION METHOD FOR DETERMINATION OF PLUTONIUM ISOTOPES IN LARGE RICE SAMPLES

    SciTech Connect

    Maxwell, S.

    2013-03-01

    A new rapid fusion method for the determination of plutonium in large rice samples has been developed at the Savannah River National Laboratory (Aiken, SC, USA) that can be used to determine very low levels of plutonium isotopes in rice. The recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid, reliable radiochemical analyses for radionuclides in environmental and food samples. Public concern regarding foods, particularly foods such as rice in Japan, highlights the need for analytical techniques that will allow very large sample aliquots of rice to be used for analysis so that very low levels of plutonium isotopes may be detected. The new method to determine plutonium isotopes in large rice samples utilizes a furnace ashing step, a rapid sodium hydroxide fusion method, a lanthanum fluoride matrix removal step, and a column separation process with TEVA Resin cartridges. The method can be applied to rice sample aliquots as large as 5 kg. Plutonium isotopes can be determined using alpha spectrometry or inductively-coupled plasma mass spectrometry (ICP-MS). The method showed high chemical recoveries and effective removal of interferences. The rapid fusion technique is a rugged sample digestion method that ensures that any refractory plutonium particles are effectively digested. The MDA for a 5 kg rice sample using alpha spectrometry is 7E-5 mBq g{sup -1}. The method can easily be adapted for use by ICP-MS to allow detection of plutonium isotopic ratios.

  2. A novel method for sampling bacteria on plant root and soil surfaces at the microhabitat scale.

    PubMed

    Dennis, Paul G; Miller, Anthony J; Clark, Ian M; Taylor, Richard G; Valsami-Jones, Eugenia; Hirsch, Penny R

    2008-09-01

    This study reports the first method for sampling bacteria at a spatial scale approximating a microhabitat. At the core of this method is the use of tungsten rods with laser-cut tips of known surface area (0.013 mm(2)). Exposed plant root or soil surfaces were viewed with a dissecting microscope and micro-sampling rods were guided to sample sites using a micro-manipulator. Bacteria that adhered to the sampling tips were then recovered for microbiological analyses. The efficiency of this method for removing bacteria from root surfaces was similar to that with which bacteria are recovered from dissected root segments using the conventional technique of washing. However, as the surface area of the micro-sampling tips was known, the new method has the advantage of eliminating inaccuracy in estimates of bacterial densities due to inaccurate estimation of the root or soil surface sampled. When used to investigate spatial distributions of rhizoplane bacteria, the new technique revealed trends that were consistent with those reported with existing methods, while providing access to additional information about community structure at a much smaller spatial scale. The spatial scale of this new method is ca. 1000-times smaller than other sampling methods involving swabbing. This novel technique represents an important methodological step facilitating microbial ecological investigations at a microhabitat scale.

  3. Rapid method to determine actinides and 89/90Sr in limestone and marble samples

    DOE PAGES

    Maxwell, Sherrod L.; Culligan, Brian; Hutchison, Jay B.; ...

    2016-04-12

    A new method for the determination of actinides and radiostrontium in limestone and marble samples has been developed that utilizes a rapid sodium hydroxide fusion to digest the sample. Following rapid pre-concentration steps to remove sample matrix interferences, the actinides and 89/90Sr are separated using extraction chromatographic resins and measured radiometrically. The advantages of sodium hydroxide fusion versus other fusion techniques will be discussed. Lastly, this approach has a sample preparation time for limestone and marble samples of <4 hours.

  4. Melting Temperature Mapping Method: A Novel Method for Rapid Identification of Unknown Pathogenic Microorganisms within Three Hours of Sample Collection

    PubMed Central

    Niimi, Hideki; Ueno, Tomohiro; Hayashi, Shirou; Abe, Akihito; Tsurue, Takahiro; Mori, Masashi; Tabata, Homare; Minami, Hiroshi; Goto, Michihiko; Akiyama, Makoto; Yamamoto, Yoshihiro; Saito, Shigeru; Kitajima, Isao

    2015-01-01

    Acquiring the earliest possible identification of pathogenic microorganisms is critical for selecting the appropriate antimicrobial therapy in infected patients. We herein report the novel “melting temperature (Tm) mapping method” for rapidly identifying the dominant bacteria in a clinical sample from sterile sites. Employing only seven primer sets, more than 100 bacterial species can be identified. In particular, using the Difference Value, it is possible to identify samples suitable for Tm mapping identification. Moreover, this method can be used to rapidly diagnose the absence of bacteria in clinical samples. We tested the Tm mapping method using 200 whole blood samples obtained from patients with suspected sepsis, 85% (171/200) of which matched the culture results based on the detection level. A total of 130 samples were negative according to the Tm mapping method, 98% (128/130) of which were also negative based on the culture method. Meanwhile, 70 samples were positive according to the Tm mapping method, and of the 59 suitable for identification, 100% (59/59) exhibited a “match” or “broad match” with the culture or sequencing results. These findings were obtained within three hours of whole blood collection. The Tm mapping method is therefore useful for identifying infectious diseases requiring prompt treatment. PMID:26218169

  5. Probe Heating Method for the Analysis of Solid Samples Using a Portable Mass Spectrometer

    PubMed Central

    Kumano, Shun; Sugiyama, Masuyuki; Yamada, Masuyoshi; Nishimura, Kazushige; Hasegawa, Hideki; Morokuma, Hidetoshi; Inoue, Hiroyuki; Hashimoto, Yuichiro

    2015-01-01

    We previously reported on the development of a portable mass spectrometer for the onsite screening of illicit drugs, but our previous sampling system could only be used for liquid samples. In this study, we report on an attempt to develop a probe heating method that also permits solid samples to be analyzed using a portable mass spectrometer. An aluminum rod is used as the sampling probe. The powdered sample is affixed to the sampling probe or a droplet of sample solution is placed on the tip of the probe and dried. The probe is then placed on a heater to vaporize the sample. The vapor is then introduced into the portable mass spectrometer and analyzed. With the heater temperature set to 130°C, the developed system detected 1 ng of methamphetamine, 1 ng of amphetamine, 3 ng of 3,4-methylenedioxymethamphetamine, 1 ng of 3,4-methylenedioxyamphetamine, and 0.3 ng of cocaine. Even from mixtures consisting of clove powder and methamphetamine powder, methamphetamine ions were detected by tandem mass spectrometry. The developed probe heating method provides a simple method for the analysis of solid samples. A portable mass spectrometer incorporating this method would thus be useful for the onsite screening of illicit drugs. PMID:26819909

  6. Probe Heating Method for the Analysis of Solid Samples Using a Portable Mass Spectrometer.

    PubMed

    Kumano, Shun; Sugiyama, Masuyuki; Yamada, Masuyoshi; Nishimura, Kazushige; Hasegawa, Hideki; Morokuma, Hidetoshi; Inoue, Hiroyuki; Hashimoto, Yuichiro

    2015-01-01

    We previously reported on the development of a portable mass spectrometer for the onsite screening of illicit drugs, but our previous sampling system could only be used for liquid samples. In this study, we report on an attempt to develop a probe heating method that also permits solid samples to be analyzed using a portable mass spectrometer. An aluminum rod is used as the sampling probe. The powdered sample is affixed to the sampling probe or a droplet of sample solution is placed on the tip of the probe and dried. The probe is then placed on a heater to vaporize the sample. The vapor is then introduced into the portable mass spectrometer and analyzed. With the heater temperature set to 130°C, the developed system detected 1 ng of methamphetamine, 1 ng of amphetamine, 3 ng of 3,4-methylenedioxymethamphetamine, 1 ng of 3,4-methylenedioxyamphetamine, and 0.3 ng of cocaine. Even from mixtures consisting of clove powder and methamphetamine powder, methamphetamine ions were detected by tandem mass spectrometry. The developed probe heating method provides a simple method for the analysis of solid samples. A portable mass spectrometer incorporating this method would thus be useful for the onsite screening of illicit drugs.

  7. Trace-element analysis of 1000 environmental samples per year using instrumental neutron activation analysis

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.

    1974-01-01

    The technology and methods developed at the Plum Brook Reactor to analyze 1000 samples per year and report data on as many as 56 elements are described. The manpower for the complete analysis of 20 to 24 samples per week required only 3 to 3.5 hours per sample. The solutions to problems encountered in sample preparation, irradiation, and counting are discussed. The automation of data reduction is described. Typical data on various sample matrices are presented.

  8. A new method for FMRI activation detection

    NASA Astrophysics Data System (ADS)

    Wei, Jianing; Talavage, Thomas M.; Pollak, Ilya

    2009-02-01

    The objective of fMRI data analysis is to detect the region of the brain that gets activated in response to a specific stimulus presented to the subject. We develop a new algorithm for activation detection in event-related fMRI data. We utilize a forward model for fMRI data acquisition which explicitly incorporates physiological noise, scanner noise and the spatial blurring introduced by the scanner. After slice-by-slice image restoration procedure that independently restores each data slice corresponding to each time index, we estimate the parameters of the hemodynamic response function (HRF) model for each pixel of the restored data. In order to enforce spatial regularity in our estimates, we model the prior distribution of the HRF parameters as a generalized Gaussian Markov random field (GGMRF) model. We develop an algorithm to compute the maximum a posteriori (MAP) estimates of the parameters. We then threshold the amplitude parameters to obtain the final activation map. We illustrate our algorithm by comparing it with the widely used general linear model (GLM) method. In synthetic data experiments, under the same probability of false alarm, the probability of correct detection for our method is up to 15% higher than GLM. In real data experiments, through anatomical analysis and benchmark testing using block paradigm results, we demonstrate that our algorithm produces fewer false alarms than GLM.

  9. Apparatus and method for maintaining multi-component sample gas constituents in vapor phase during sample extraction and cooling

    DOEpatents

    Felix, Larry Gordon; Farthing, William Earl; Irvin, James Hodges; Snyder, Todd Robert

    2010-05-11

    A dilution apparatus for diluting a gas sample. The apparatus includes a sample gas conduit having a sample gas inlet end and a diluted sample gas outlet end, and a sample gas flow restricting orifice disposed proximate the sample gas inlet end connected with the sample gas conduit and providing fluid communication between the exterior and the interior of the sample gas conduit. A diluted sample gas conduit is provided within the sample gas conduit having a mixing end with a mixing space inlet opening disposed proximate the sample gas inlet end, thereby forming an annular space between the sample gas conduit and the diluted sample gas conduit. The mixing end of the diluted sample gas conduit is disposed at a distance from the sample gas flow restricting orifice. A dilution gas source connected with the sample gas inlet end of the sample gas conduit is provided for introducing a dilution gas into the annular space, and a filter is provided for filtering the sample gas. The apparatus is particularly suited for diluting heated sample gases containing one or more condensable components.

  10. The effect of sampling methods on the apparent constituents of ink from the squid Sepioteuthis australis.

    PubMed

    Madaras, F; Gerber, J P; Peddie, F; Kokkinn, M J

    2010-11-01

    Results of experiments conducted on ink recovered from the squid Sepioteuthis australis indicate that there is no epinephrine or protein naturally present in the ink as it would be ejected in vivo. Protein content was effectively zero when ink was syringed from the duct end of the ink sac of freshly killed animals. By contrast, there were proteins in samples collected from dead specimens where ink was collected by a stripping method. From these samples, a single large molecular weight protein was identified as having tyrosinase activity. Digestion of syringed ink did not yield signs of melanin-bound proteins. Analysis of supernatants after centrifugation of squid ink consistently revealed the presence of DOPA, dopamine, and taurine, whereas epinephrine and nor-epinephrine were recorded from what was believed to be contaminated ink. Histological investigations of the ink sac revealed a compartmentalised glandular structure distal to the duct end. Closer observation of the glandular tissue showed that compartments increased in size as they matured and moved further into the lumen. It was concluded that the presence of epinephrine and tyrosinase (or a related protein) in the ink of S. australis could be attributed to rupturing of basal glandular compartments or contamination from other sources during the extraction process.

  11. Passive sampling methods for contaminated sediments: scientific rationale supporting use of freely dissolved concentrations.

    PubMed

    Mayer, Philipp; Parkerton, Thomas F; Adams, Rachel G; Cargill, John G; Gan, Jay; Gouin, Todd; Gschwend, Philip M; Hawthorne, Steven B; Helm, Paul; Witt, Gesine; You, Jing; Escher, Beate I

    2014-04-01

    Passive sampling methods (PSMs) allow the quantification of the freely dissolved concentration (Cfree ) of an organic contaminant even in complex matrices such as sediments. Cfree is directly related to a contaminant's chemical activity, which drives spontaneous processes including diffusive uptake into benthic organisms and exchange with the overlying water column. Consequently, Cfree provides a more relevant dose metric than total sediment concentration. Recent developments in PSMs have significantly improved our ability to reliably measure even very low levels of Cfree . Application of PSMs in sediments is preferably conducted in the equilibrium regime, where freely dissolved concentrations in the sediment are well-linked to the measured concentration in the sampler via analyte-specific partition ratios. The equilibrium condition can then be assured by measuring a time series or a single time point using passive samplers with different surface to volume ratios. Sampling in the kinetic regime is also possible and generally involves the application of performance reference compounds for the calibration. Based on previous research on hydrophobic organic contaminants, it is concluded that Cfree allows a direct assessment of 1) contaminant exchange and equilibrium status between sediment and overlying water, 2) benthic bioaccumulation, and 3) potential toxicity to benthic organisms. Thus, the use of PSMs to measure Cfree provides an improved basis for the mechanistic understanding of fate and transport processes in sediments and has the potential to significantly improve risk assessment and management of contaminated sediments.

  12. Passive sampling methods for contaminated sediments: State of the science for organic contaminants

    PubMed Central

    Lydy, Michael J; Landrum, Peter F; Oen, Amy MP; Allinson, Mayumi; Smedes, Foppe; Harwood, Amanda D; Li, Huizhen; Maruya, Keith A; Liu, Jingfu

    2014-01-01

    This manuscript surveys the literature on passive sampler methods (PSMs) used in contaminated sediments to assess the chemical activity of organic contaminants. The chemical activity in turn dictates the reactivity and bioavailability of contaminants in sediment. Approaches to measure specific binding of compounds to sediment components, for example, amorphous carbon or specific types of reduced carbon, and the associated partition coefficients are difficult to determine, particularly for native sediment. Thus, the development of PSMs that represent the chemical activity of complex compound–sediment interactions, expressed as the freely dissolved contaminant concentration in porewater (Cfree), offer a better proxy for endpoints of concern, such as reactivity, bioaccumulation, and toxicity. Passive sampling methods have estimated Cfree using both kinetic and equilibrium operating modes and used various polymers as the sorbing phase, for example, polydimethylsiloxane, polyethylene, and polyoxymethylene in various configurations, such as sheets, coated fibers, or vials containing thin films. These PSMs have been applied in laboratory exposures and field deployments covering a variety of spatial and temporal scales. A wide range of calibration conditions exist in the literature to estimate Cfree, but consensus values have not been established. The most critical criteria are the partition coefficient between water and the polymer phase and the equilibrium status of the sampler. In addition, the PSM must not appreciably deplete Cfree in the porewater. Some of the future challenges include establishing a standard approach for PSM measurements, correcting for nonequilibrium conditions, establishing guidance for selection and implementation of PSMs, and translating and applying data collected by PSMs. Integr Environ Assess Manag 2014;10:167–178. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of

  13. Methods, compounds and systems for detecting a microorganism in a sample

    DOEpatents

    Colston, Jr, Bill W.; Fitch, J. Patrick; Gardner, Shea N.; Williams, Peter L.; Wagner, Mark C.

    2016-09-06

    Methods to identify a set of probe polynucleotides suitable for detecting a set of targets and in particular methods for identification of primers suitable for detection of target microorganisms related polynucleotides, set of polynucleotides and compositions, and related methods and systems for detection and/or identification of microorganisms in a sample.

  14. A COMPARISON OF SIX BENTHIC MACROINVERTEBRATE SAMPLING METHODS IN FOUR LARGE RIVERS

    EPA Science Inventory

    In 1999, a study was conducted to compare six macroinvertebrate sampling methods in four large (boatable) rivers that drain into the Ohio River. Two methods each were adapted from existing methods used by the USEPA, USGS and Ohio EPA. Drift nets were unable to collect a suffici...

  15. Comparison of dust sampling methods in Estonia and Sweden--a field study.

    PubMed

    Berg, P; Jaakmees, V; Bodin, L

    1999-09-01

    The purpose of this field study was to compare an Estonian dust sampling method, a method also used in other former East Block countries, with a Swedish method and to estimate inter-method agreement with statistical analyses. The Estonian standard method (ESM), used to assess exposure in Estonia since the early 1950s, is based on a strategy where air samples are collected for 10 minutes every hour over a full shift. This method was compared to a Swedish standard method (SSM), a modified NIOSH method, comparable to international standards, where one air sample is collected during a full shift. The study was carried out at a cement plant that in the beginning of the 1990s was subjected to an epidemiological study, including collection of exposure data. The results of the analysis from 31 clusters of parallel samples of the two methods, when dust consisting of Portland cement was collected, showed a relatively weak correlation between the SSM and the ESM, ri = 0.81 (Pearson's intra-class correlation coefficient). A conversion factor between the two methods was estimated, where SSM is 0.69 times ESM and the limits of agreement are 0.25 and 1.84, respectively. These results indicate a substantial inter-method difference. We therefore recommend that measurements obtained from the two methods should not be used interchangeably. Because the present study is of limited extent, our findings are confined to the operations studied and further studies covering other exposure situations will be needed.

  16. High-throughput DNA isolation method for detection of Xylella fastidiosa in plant and insect samples.

    PubMed

    Brady, Jeff A; Faske, Jennifer B; Castañeda-Gill, Jessica M; King, Jonathan L; Mitchell, Forrest L

    2011-09-01

    We report an inexpensive, high-throughput method for isolating DNA from insect and plant samples for the purpose of detecting Xylella fastidiosa infection. Existing methods often copurify inhibitors of DNA polymerases, limiting their usefulness for PCR-based detection assays. When compared to commercially available kits, the method provides enhanced pathogen detection at a fraction of the cost.

  17. 40 CFR 80.580 - What are the sampling and testing methods for sulfur?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... methods for sulfur? 80.580 Section 80.580 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... the sampling and testing methods for sulfur? The sulfur content of diesel fuel and diesel fuel... methodology is provided in § 80.330(b). (b) Test method for sulfur—(1) For ECA marine fuel subject to the...

  18. 40 CFR 80.580 - What are the sampling and testing methods for sulfur?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... methods for sulfur? 80.580 Section 80.580 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... the sampling and testing methods for sulfur? The sulfur content of diesel fuel and diesel fuel... methodology is provided in § 80.330(b). (b) Test method for sulfur—(1) For ECA marine fuel subject to the...

  19. 40 CFR 80.580 - What are the sampling and testing methods for sulfur?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... methods for sulfur? 80.580 Section 80.580 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... the sampling and testing methods for sulfur? The sulfur content of diesel fuel and diesel fuel... methodology is provided in § 80.330(b). (b) Test method for sulfur—(1) For ECA marine fuel subject to the...

  20. NREL Develops Accelerated Sample Activation Process for Hydrogen Storage Materials (Fact Sheet)

    SciTech Connect

    Not Available

    2010-12-01

    This fact sheet describes NREL's accomplishments in developing a new sample activation process that reduces the time to prepare samples for measurement of hydrogen storage from several days to five minutes and provides more uniform samples. Work was performed by NREL's Chemical and Materials Science Center.

  1. Transfer of sampling methods for studies on most-at-risk populations (MARPs) in Brazil.

    PubMed

    Barbosa Júnior, Aristides; Pascom, Ana Roberta Pati; Szwarcwald, Célia Landmann; Kendall, Carl; McFarland, Willi

    2011-01-01

    The objective of this paper was to describe the process of transferring two methods for sampling most-at-risk populations: respondent-driven sampling (RDS) and time-space sampling (TSS). The article describes steps in the process, the methods used in the 10 pilot studies, and lessons learned. The process was conducted in six steps, from a state-of-the-art seminar to a workshop on writing articles with the results of the pilot studies. The principal investigators reported difficulties in the fieldwork and data analysis, independently of the pilot sampling method. One of the most important results of the transfer process is that Brazil now has more than 100 researchers able to sample MARPs using RDS or TSS. The process also enabled the construction of baselines for MARPS, thus providing a broader understanding of the dynamics of HIV infection in the country and the use of evidence to plan the national response to the epidemic in these groups.

  2. A comparison of microscopic and spectroscopic identification methods for analysis of microplastics in environmental samples.

    PubMed

    Song, Young Kyoung; Hong, Sang Hee; Jang, Mi; Han, Gi Myung; Rani, Manviri; Lee, Jongmyoung; Shim, Won Joon

    2015-04-15

    The analysis of microplastics in various environmental samples requires the identification of microplastics from natural materials. The identification technique lacks a standardized protocol. Herein, stereomicroscope and Fourier transform infrared spectroscope (FT-IR) identification methods for microplastics (<1mm) were compared using the same samples from the sea surface microlayer (SML) and beach sand. Fragmented microplastics were significantly (p<0.05) underestimated and fiber was significantly overestimated using the stereomicroscope both in the SML and beach samples. The total abundance by FT-IR was higher than by microscope both in the SML and beach samples, but they were not significantly (p>0.05) different. Depending on the number of samples and the microplastic size range of interest, the appropriate identification method should be determined; selecting a suitable identification method for microplastics is crucial for evaluating microplastic pollution.

  3. Analytical determination of flavonoids aimed to analysis of natural samples and active packaging applications.

    PubMed

    Castro-López, María del Mar; López-Vilariño, José Manuel; González-Rodríguez, María Victoria

    2014-05-01

    Several HPLC and UHPLC developed methods were compared to analyse the natural antioxidants catechins and quercetin used in active packaging and functional foods. Photodiode array detector coupled with a fluorescence detector and compared with LTQ-Orbitrap-MS was used. UHPLC was investigated as quick alternative without compromising the separation, analysis time shortened up to 6-fold. The feasibility of the four developed methods was compared. Linearity up to 0.9995, low detection limits (between 0.02 and 0.7 for HPLC-PDA, 2 to 7-fold lower for HPLC- LTQ-Orbitrap-MS and from 0.2 to 2mgL(-)(1) for UHPLC-PDA) and good precision parameters (RSD lower than 0.06%) were obtained. All methods were successfully applied to natural samples. LTQ-Orbitrap-MS allowed to identify other analytes of interest too. Good feasibility of the methods was also concluded from the analysis of catechin and quercetin release from new active packaging materials based on polypropylene added with catechins and green tea.

  4. Study of activation of metal samples from LDEF-1 and Spacelab-2

    NASA Technical Reports Server (NTRS)

    Laird, C. E.

    1991-01-01

    The activation of metal samples and other material orbited onboard the Long Duration Exposure Facility (LDEF) and Spacelab-2 were studied. Measurements of the radioactivities of spacecraft materials were made, and corrections for self-absorption and efficiency were calculated. Activation cross sections for specific metal samples were updated while cross sections for other materials were tabulated from the scientific literature. Activation cross sections for 200 MeV neutrons were experimentally determined. Linear absorption coefficients, half lives, branching ratios and other pertinent technical data needed for LDEF sample analyses were tabulated. The status of the sample counting at low background facilities at national laboratories is reported.

  5. A Study Of The Radionuclidic Content Of The Environmental Samples Resulting From NIPNE Activities

    SciTech Connect

    Stochioiu, Ana I.; Bercea, Sorin I.; Ivan, Constantin G.; Dumitru, Octavian R.; Pantelica, Ana I.

    2007-04-23

    The results of alpha, beta, gamma global activity measurements and gamma spectrometric measurements are presented. For more detailed characterization of samples, gamma-spectrometric measurement, implying identification of radionuclides and their activities are carried-out on significant ambiental annual samples.

  6. A SIMPLE METHOD FOR DETERMINATION OF CAFFEINE CONTENT IN TEA SAMPLES

    PubMed Central

    Venkatesh, Sama; Swamy, M.M.; Reddy, Y.S.R.; Suresh, B.; Sethuraman, M.

    1994-01-01

    The present communication describes a simple and modified colorimetric procedure for the estimation of caffeine content in both commercial and locally available tea samples. Comparative data of caffeine content in different brands of tea samples are shown here. The present method is no doubt an improvised procedure for estimating directly caffeine content from the tea extracts. A possible explanation to account for the variability in caffeine content in different samples is offered. PMID:22556672

  7. Probabilistic Requirements (Partial) Verification Methods Best Practices Improvement. Variables Acceptance Sampling Calculators: Empirical Testing. Volume 2

    NASA Technical Reports Server (NTRS)

    Johnson, Kenneth L.; White, K. Preston, Jr.

    2012-01-01

    The NASA Engineering and Safety Center was requested to improve on the Best Practices document produced for the NESC assessment, Verification of Probabilistic Requirements for the Constellation Program, by giving a recommended procedure for using acceptance sampling by variables techniques as an alternative to the potentially resource-intensive acceptance sampling by attributes method given in the document. In this paper, the results of empirical tests intended to assess the accuracy of acceptance sampling plan calculators implemented for six variable distributions are presented.

  8. A unified method to process biosolids samples for the recovery of bacterial, viral, and helminths pathogens.

    PubMed

    Alum, Absar; Rock, Channah; Abbaszadegan, Morteza

    2014-01-01

    For land application, biosolids are classified as Class A or Class B based on the levels of bacterial, viral, and helminths pathogens in residual biosolids. The current EPA methods for the detection of these groups of pathogens in biosolids include discrete steps. Therefore, a separate sample is processed independently to quantify the number of each group of the pathogens in biosolids. The aim of the study was to develop a unified method for simultaneous processing of a single biosolids sample to recover bacterial, viral, and helminths pathogens. At the first stage for developing a simultaneous method, nine eluents were compared for their efficiency to recover viruses from a 100 gm spiked biosolids sample. In the second stage, the three top performing eluents were thoroughly evaluated for the recovery of bacteria, viruses, and helminthes. For all three groups of pathogens, the glycine-based eluent provided higher recovery than the beef extract-based eluent. Additional experiments were performed to optimize performance of glycine-based eluent under various procedural factors such as, solids to eluent ratio, stir time, and centrifugation conditions. Last, the new method was directly compared with the EPA methods for the recovery of the three groups of pathogens spiked in duplicate samples of biosolids collected from different sources. For viruses, the new method yielded up to 10% higher recoveries than the EPA method. For bacteria and helminths, recoveries were 74% and 83% by the new method compared to 34% and 68% by the EPA method, respectively. The unified sample processing method significantly reduces the time required for processing biosolids samples for different groups of pathogens; it is less impacted by the intrinsic variability of samples, while providing higher yields (P = 0.05) and greater consistency than the current EPA methods.

  9. Application of the van der Pauw method for samples with holes

    NASA Astrophysics Data System (ADS)

    Oh, Donggeon; Ahn, Cheongeung; Kim, Minchul; Park, Eung-Kyu; Kim, Yong-Sang

    2016-12-01

    Modifications of the original van der Pauw relation were suggested recently. The methods are applicable to samples with a hole, unlike the original van der Pauw relation, but it takes too much time and effort to apply the methods to samples with high randomness. So in this paper we suggest two generalizations of the van der Pauw method which are applicable for two-dimensional homogeneous systems with a finite number of holes. Both methods rely on obtaining a crucial constant of the system, ν. The first method involves setting the probes far from each other while conducting the experiment using a sample with a small hole, approximating a relation that gives ν as a linear function of the area ratio of the hole only. The second method produces an identical sample of known resistivity and thickness to obtain ν, which is believed to be dependent on the geometrical properties only. Unlike the earlier methods, which entailed complex procedures, little in the way of measurements and computation is needed for the new methods. The methods will be very useful in electric experiments or industries which need to measure the resistivity of samples.

  10. Advances in sample preparation in electromigration, chromatographic and mass spectrometric separation methods.

    PubMed

    Gilar, M; Bouvier, E S; Compton, B J

    2001-02-16

    The quality of sample preparation is a key factor in determining the success of analysis. While analysis of pharmaceutically important compounds in biological matrixes has driven forward the development of sample clean-up procedures in last 20 years, today's chemists face an additional challenge: sample preparation and analysis of complex biochemical samples for characterization of genotypic or phenotypic information contained in DNA and proteins. This review focuses on various sample pretreatment methods designed to meet the requirements for the analysis of biopolymers and small drugs in complex matrices. We discuss the advances in development of solid-phase extraction (SPE) sorbents, on-line SPE, membrane-based sample preparation, and sample clean-up of biopolymers prior to their analysis by mass spectrometry.

  11. A venue-based method for sampling hard-to-reach populations.

    PubMed Central

    Muhib, F. B.; Lin, L. S.; Stueve, A.; Miller, R. L.; Ford, W. L.; Johnson, W. D.; Smith, P. J.

    2001-01-01

    Constructing scientifically sound samples of hard-to-reach populations, also known as hidden populations, is a challenge for many research projects. Traditional sample survey methods, such as random sampling from telephone or mailing lists, can yield low numbers of eligible respondents while non-probability sampling introduces unknown biases. The authors describe a venue-based application of time-space sampling (TSS) that addresses the challenges of accessing hard-to-reach populations. The method entails identifying days and times when the target population gathers at specific venues, constructing a sampling frame of venue, day-time units (VDTs), randomly selecting and visiting VDTs (the primary sampling units), and systematically intercepting and collecting information from consenting members of the target population. This allows researchers to construct a sample with known properties, make statistical inference to the larger population of venue visitors, and theorize about the introduction of biases that may limit generalization of results to the target population. The authors describe their use of TSS in the ongoing Community Intervention Trial for Youth (CITY) project to generate a systematic sample of young men who have sex with men. The project is an ongoing community level HIV prevention intervention trial funded by the Centers for Disease Control and Prevention. The TSS method is reproducible and can be adapted to hard-to-reach populations in other situations, environments, and cultures. PMID:11889287

  12. Development and Evaluation of a Micro- and Nanoscale Proteomic Sample Preparation Method

    SciTech Connect

    Wang, Haixing H.; Qian, Weijun; Mottaz, Heather M.; Clauss, Therese R.W.; Anderson, David J.; Moore, Ronald J.; Camp, David G.; Khan, Arshad H.; Sforza, Daniel M.; Pallavicini, Maria; Smith, Desmond J.; Smith, Richard D.

    2005-10-05

    Efficient and effective sample preparation of micro- and nano-scale (micro- and nano-gram) clinical specimens for proteomic applications is often difficult due to losses during the processing steps. Herein we describe a simple “single-tube” preparation protocol appropriate for small proteomic samples using the organic co-solvent, trifluoroethanol (TFE). TFE facilitates both protein extraction and protein denaturation without requiring a separate cleanup step, thus minimizing sample loss. The performance of the TFE method was initially evaluated by comparing to traditional detergent-based methods on relatively large scale sample processing using human breast cancer cells and mouse brain tissue. The results demonstrated that the TFE protocol provided comparable results to the traditional detergent-based protocols for larger samples (milligrams), based on both sample recovery and peptide/protein identification. The effectiveness of this protocol for micro- and nano-scale sample processing was then evaluated for the extraction of proteins/peptides and shown effective for small mouse brain tissue samples (~ 20 μg total protein content) and also for samples of ~ 5 000 human breast cancer MCF-7 cells (~ 500 ng total protein content), where the detergent-based methods were ineffective due to losses during cleanup and transfer steps.

  13. GROUND WATER MONITORING AND SAMPLING: MULTI-LEVEL VERSUS TRADITIONAL METHODS WHATS WHAT?

    EPA Science Inventory

    After years of research and many publications, the question still remains: What is the best method to collect representative ground water samples from monitoring wells? Numerous systems and devices are currently available for obtaining both multi-level samples as well as traditi...

  14. Fast identification of microplastics in complex environmental samples by a thermal degradation method.

    PubMed

    Dümichen, Erik; Eisentraut, Paul; Bannick, Claus Gerhard; Barthel, Anne-Kathrin; Senz, Rainer; Braun, Ulrike

    2017-05-01

    In order to determine the relevance of microplastic particles in various environmental media, comprehensive investigations are needed. However, no analytical method exists for fast identification and quantification. At present, optical spectroscopy methods like IR and RAMAN imaging are used. Due to their time consuming procedures and uncertain extrapolation, reliable monitoring is difficult. For analyzing polymers Py-GC-MS is a standard method. However, due to a limited sample amount of about 0.5 mg it is not suited for analysis of complex sample mixtures like environmental samples. Therefore, we developed a new thermoanalytical method as a first step for identifying microplastics in environmental samples. A sample amount of about 20 mg, which assures the homogeneity of the sample, is subjected to complete thermal decomposition. The specific degradation products of the respective polymer are adsorbed on a solid-phase adsorber and subsequently analyzed by thermal desorption gas chromatography mass spectrometry. For certain identification, the specific degradation products for the respective polymer were selected first. Afterwards real environmental samples from the aquatic (three different rivers) and the terrestrial (bio gas plant) systems were screened for microplastics. Mainly polypropylene (PP), polyethylene (PE) and polystyrene (PS) were identified for the samples from the bio gas plant and PE and PS from the rivers. However, this was only the first step and quantification measurements will follow.

  15. Effectiveness of Four Methods of Handling Missing Data Using Samples from a National Database.

    ERIC Educational Resources Information Center

    Witta, E. Lea

    The effectiveness of four methods of handling missing data in reproducing the target sample covariance matrix and mean vector was tested using three levels of incomplete cases: 30%, 50%, and 70%. Data were selected from the National Education Longitudinal Study (NELS) database. Three levels of sample sizes (500, 1000, and 2000) were used. The…

  16. Aerostat-lofted instrument and sampling method for determination of emissions from open area sources

    EPA Science Inventory

    An aerostat-borne instrument and sampling method was developed to characterize air samples from area sources, such as emissions from open burning. The 10 kg battery-powered instrument system, termed "the Flyer," is lofted with a helium-filled aerostat of 4 m nominal diameter and ...

  17. The "Closed School-Cluster" Method of Selecting a Probability Sample.

    ERIC Educational Resources Information Center

    Shaycoft, Marion F.

    In some educational research studies--particularly longitudinal studies requiring a probability sample of schools and spanning a wide range of grades--it is desirable to so select the sample that schools at different levels (e.g., elementary and secondary) "correspond." This has often proved unachievable, using standard methods of selecting school…

  18. Method and apparatus for measuring the NMR spectrum of an orientationally disordered sample

    DOEpatents

    Pines, Alexander; Samoson, Ago

    1990-01-01

    An improved NMR probe and method are described which substantially improve the resolution of NMR measurements made on powdered or amorphous or otherwise oreintationally disordered samples. The apparatus mechanically varies the orientation of the sample such that the time average of two or more sets of spherical harmonic functions is zero.

  19. Comparison of alternative methods, sample grinds, and fermentation times for determining indigestible neutral detergent fiber

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of this study were to evaluate the effects of sample grind, fermentation method, and time on the determination of indigestible neutral detergent fiber (iNDF). Samples of: 1) alfalfa hay and silage, 2) corn stalks and silage, and 3) ryegrass and mixed grass hays were ground through 2-m...

  20. Design Study of Methods for Sampling Migrant and Seasonal Farm Workers. Final Report.

    ERIC Educational Resources Information Center

    Kalsbeek, William D.; Parker, Rebecca Robin

    This report describes efforts to develop sampling methods to be used in national or regional studies of migrant and seasonal farm workers (MSFWs). Several facets of the MSFWs' lifestyle create sampling difficulties. One is mobility. Although the dynamic nature of MSFWs' movement is partly understood, it is sufficiently unpredictable to create…

  1. Drying and storage methods affect cyfluthrin concentrations in exposed plant samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Standard procedures exist for collection and chemical analyses of pyrethroid insecticides in environmental matrices. However, less detail is given for drying and potential storage methods of plant samples prior to analyses. Due to equipment and financial limitations, immediate sample analysis is n...

  2. Environmental Sampling Procedures and Methods to Respond to Biological Contamination (White Powder)

    SciTech Connect

    Piepel, Gregory F.; Amidan, Brett G.; Matzke, Brett D.

    2008-11-01

    This is a contribution to the annual report for the DHS Standards Office. It summarizes statistics-focused work associated with developing validated sampling procedures and methods. The main focus is on the experimental and sampling design constructed for contamination and decontamination field tests conducted during September 2007 in a remote, unused office building on the Idaho National Laboratory site.

  3. Evaluation and characterization of thyroid-disrupting activities in soil samples along the Second Songhua River, China.

    PubMed

    Kong, Dongdong; Wang, Yafei; Wang, Jinsheng; Teng, Yanguo; Li, Na; Li, Jian

    2016-11-01

    In this study, a recombinant thyroid receptor (TR) gene yeast assay combined with Monte Carlo simulation were used to evaluate and characterize soil samples collected from Jilin (China) along the Second Songhua River, for their ant/agonist effect on TR. No TR agonistic activity was found in soils, but many soil samples exhibited TR antagonistic activities, and the bioassay-derived amiodarone hydrochloride equivalents, which was calculated based on Monte Carlo simulation, ranged from not detected (N.D.) to 35.5μg/g. Hydrophilic substance fractions were determined to be the contributors to TR antagonistic activity in these soil samples. Our results indicate that the novel calculation method is effective for the quantification and characterization of TR antagonists in soil samples, and these data could provide useful information for future management and remediation efforts for contaminated soils.

  4. System and method for monitoring cellular activity

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H. (Inventor); Fraser, Scott E. (Inventor); Lansford, Russell D. (Inventor)

    2004-01-01

    A system and method for monitoring cellular activity in a cellular specimen. According to one embodiment, a plurality of excitable markers are applied to the specimen. A multi-photon laser microscope is provided to excite a region of the specimen and cause fluorescence to be radiated from the region. The radiating fluorescence is processed by a spectral analyzer to separate the fluorescence into respective wavelength bands. The respective bands of fluorescence are then collected by an array of detectors, with each detector receiving a corresponding one of the wavelength bands.

  5. System and method for monitoring cellular activity

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H. (Inventor); Fraser, Scott E. (Inventor); Lansford, Russell D. (Inventor)

    2002-01-01

    A system and method for monitoring cellular activity in a cellular specimen. According to one embodiment, a plurality of excitable markers are applied to the specimen. A multi-photon laser microscope is provided to excite a region of the specimen and cause fluorescence to be radiated from the region. The radiating fluorescence is processed by a spectral analyzer to separate the fluorescence into respective wavelength bands. The respective bands of fluorescence are then collected by an array of detectors, with each detector receiving a corresponding one of the wavelength bands.

  6. Dual stage active magnetic regenerator and method

    DOEpatents

    Pecharsky, Vitalij K.; Gschneidner, Jr., Karl A.

    1999-03-30

    A dual stage active magnetic regenerator refrigerator as well as method using the Joule-Brayton thermodynamic cycle includes a high temperature stage refrigerant comprising DyAl.sub.2 or (Dy.sub.1-x Er.sub.x)Al.sub.2 where x is selected to be greater than 0 and less than about 0.3 in combination with a low temperature stage comprising (Dy.sub.1-x Er.sub.x)Al.sub.2 where x is selected to be greater than about 0.5 and less than 1 to provide significantly improved refrigeration efficiency in the liquefaction of gaseous hydrogen.

  7. Dual stage active magnetic regenerator and method

    DOEpatents

    Pecharsky, V.K.; Gschneidner, K.A. Jr.

    1999-03-30

    A dual stage active magnetic regenerator refrigerator as well as method using the Joule-Brayton thermodynamic cycle includes a high temperature stage refrigerant comprising DyAl{sub 2} or (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} where x is selected to be greater than 0 and less than about 0.3 in combination with a low temperature stage comprising (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} where x is selected to be greater than about 0.5 and less than 1 to provide significantly improved refrigeration efficiency in the liquefaction of gaseous hydrogen. 17 figs.

  8. Quantification of creatinine in biological samples based on the pseudoenzyme activity of copper-creatinine complex

    NASA Astrophysics Data System (ADS)

    Nagaraja, Padmarajaiah; Avinash, Krishnegowda; Shivakumar, Anantharaman; Krishna, Honnur

    Glomerular filtration rate (GFR), the marker of chronic kidney disease can be analyzed by the concentration of cystatin C or creatinine and its clearance in human urine and serum samples. The determination of cystatin C alone as an indicator of GFR does not provide high accuracy, and is more expensive, thus measurement of creatinine has an important role in estimating GFR. We have made an attempt to quantify creatinine based on its pseudoenzyme activity of creatinine in the presence of copper. Creatinine in the presence of copper oxidizes paraphenylenediamine dihydrochloride (PPDD) which couples with dimethylamino benzoicacid (DMAB) giving green colored chromogenic product with maximum absorbance at 710 nm. Kinetic parameters relating this reaction were evaluated. Analytical curves of creatinine by fixed time and rate methods were linear at 8.8-530 μmol L-1 and 0.221-2.65 mmol L-1, respectively. Recovery of creatinine varied from 97.8 to 107.8%. Limit of detection and limit of quantification were 2.55 and 8.52 μmol L-1 respectively whereas Sandell's sensitivity and molar absorption coefficient values were 0.0407 μg cm-2 and 0.1427 × 104 L mol-1 cm-1 respectively. Precision studies showed that within day imprecision was 0.745-1.26% and day-to-day imprecision was 1.55-3.65%. The proposed method was applied to human urine and serum samples and results were validated in accordance with modified Jaffe's procedure. Wide linearity ranges with good recovery, less tolerance from excipients and application of the method to serum and urine samples are the claims which ascertain much advantage to this method.

  9. A Combined Metadynamics and Umbrella Sampling Method for the Calculation of Ion Permeation Free Energy Profiles

    PubMed Central

    Zhang, Yong; Voth, Gregory A.

    2011-01-01

    Free energy calculations are one of the most useful methods for the study of ion transport mechanisms through confined spaces such as protein ion channels. Their reliability depends on a correctly defined reaction coordinate (RC). A straight line is usually not a proper RC for such complicated processes so in this work a combined metadynamics/umbrella sampling (MTD/US) method is proposed. In the combined method, the ion transport pathway is first identified by the MTD method and then the free energy profile or potential of mean force (PMF) along the path is calculated using umbrella sampling. This combined method avoids the discontinuity problem often associated with normal umbrella sampling calculations that assume a straight line RC and it provides a more physically accurate PMF for such processes. The method is demonstrated for the proton transport process through the protein channel of aquaporin-1. PMID:25100923

  10. Comparison of dust sampling methods in Estonia and Sweden -- A field study

    SciTech Connect

    Berg, P.; Jaakmees, V.; Bodin, L.

    1999-09-01

    The purpose of this field study was to compare an Estonian dust sampling method, a method also used in other former East Block countries, with a Swedish method and to estimate inter-method agreement with statistical analyses. The Estonian standard method (ESM), used to assess exposure in Estonia since the early 1950s, is based on a strategy where air samples are collected for 10 minutes every hour over a full shift. This method was compared to a Swedish standard method (SSM), a modified NIOSH method, comparable to international standards, where one air sample is collected during a full shift. The study was carried out at a cement plant that in the beginning of the 1990s was subjected to an epidemiological study, including collection of exposure data. The results of the analysis from 31 clusters of parallel samples of the two methods, when dust consisting of Portland cement was collected, showed a relatively weak correlation between the SSM and the ESM, r{sub i} = 0.91 (Pearson's intro-class correlation coefficient). A conversion factor between the two methods was estimated, where SSM is 0.69 times ESm and the limits of agreement are 0.25 and 1.84, respectively. These results indicate a substantial intermethod difference. The authors therefore recommend that measurements obtained from the two methods should not be used interchangeably. Because the present study is of limited extent, the findings are confined to the operations studied and further studies covering other exposure situation will be needed.

  11. Referred Air Method 25E: Determination of a Vapor Phase Organic Concentration in Waste Samples

    EPA Pesticide Factsheets

    This method is applicable for determining the vapor pressure of waste. The headspace vapor of the sample is analyzed for carbon content by a headspace analyzer, which uses a flame ionization detector (FID).

  12. Field Sampling and Selecting On-Site Analytical Methods for Explosives in Soil

    EPA Pesticide Factsheets

    The purpose of this issue paper is to provide guidance to Remedial Project Managers regarding field sampling and on-site analytical methods fordetecting and quantifying secondary explosive compounds in soils.

  13. 43 CFR 11.64 - Injury determination phase-testing and sampling methods.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... established, including a description of the following: (A) Hydraulic geometry, physiographic features, and... the air resource. Air modeling methods may be used for injury determination only when air sampling...

  14. 43 CFR 11.64 - Injury determination phase-testing and sampling methods.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... established, including a description of the following: (A) Hydraulic geometry, physiographic features, and... the air resource. Air modeling methods may be used for injury determination only when air sampling...

  15. A New Automated Method and Sample Data Flow for Analysis of Volatile Nitrosamines in Human Urine*

    PubMed Central

    Hodgson, James A.; Seyler, Tiffany H.; McGahee, Ernest; Arnstein, Stephen; Wang, Lanqing

    2016-01-01

    Volatile nitrosamines (VNAs) are a group of compounds classified as probable (group 2A) and possible (group 2B) carcinogens in humans. Along with certain foods and contaminated drinking water, VNAs are detected at high levels in tobacco products and in both mainstream and sidestream smoke. Our laboratory monitors six urinary VNAs—N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), N-nitrosopyrrolidine (NPYR), and N-nitrosomorpholine (NMOR)—using isotope dilution GC-MS/MS (QQQ) for large population studies such as the National Health and Nutrition Examination Survey (NHANES). In this paper, we report for the first time a new automated sample preparation method to more efficiently quantitate these VNAs. Automation is done using Hamilton STAR™ and Caliper Staccato™ workstations. This new automated method reduces sample preparation time from 4 hours to 2.5 hours while maintaining precision (inter-run CV < 10%) and accuracy (85% - 111%). More importantly this method increases sample throughput while maintaining a low limit of detection (<10 pg/mL) for all analytes. A streamlined sample data flow was created in parallel to the automated method, in which samples can be tracked from receiving to final LIMs output with minimal human intervention, further minimizing human error in the sample preparation process. This new automated method and the sample data flow are currently applied in bio-monitoring of VNAs in the US non-institutionalized population NHANES 2013-2014 cycle. PMID:26949569

  16. Sample preparation method for glass welding by ultrashort laser pulses yields higher seam strength

    SciTech Connect

    Cvecek, K.; Miyamoto, I.; Strauss, J.; Wolf, M.; Frick, T.; Schmidt, M.

    2011-05-01

    Glass welding by ultrashort laser pulses allows joining without the need of an absorber or a preheating and postheating process. However, cracks generated during the welding process substantially impair the joining strength of the welding seams. In this paper a sample preparation method is described that prevents the formation of cracks. The measured joining strength of samples prepared by this method is substantially higher than previously reported values.

  17. Applicability of Demirjian's four methods and Willems method for age estimation in a sample of Turkish children.

    PubMed

    Akkaya, Nursel; Yilanci, Hümeyra Özge; Göksülük, Dinçer

    2015-09-01

    The aim of this study was to evaluate applicability of five dental methods including Demirjian's original, revised, four teeth, and alternate four teeth methods and Willems method for age estimation in a sample of Turkish children. Panoramic radiographs of 799 children (412 females, 387 males) aged between 2.20 and 15.99years were examined by two observers. A repeated measures ANOVA was performed to compare dental methods among gender and age groups. All of the five methods overestimated the chronological age on the average. Among these, Willems method was found to be the most accurate method, which showed 0.07 and 0.15years overestimation for males and females, respectively. It was followed by Demirjian's four teeth methods, revised and original methods. According to the results, Willems method can be recommended for dental age estimation of Turkish children in forensic applications.

  18. Mitochondrial Respiration Chain Enzymatic Activities in the Human Brain: Methodological Implications for Tissue Sampling and Storage.

    PubMed

    Ronsoni, Marcelo Fernando; Remor, Aline Pertile; Lopes, Mark William; Hohl, Alexandre; Troncoso, Iris H Z; Leal, Rodrigo Bainy; Boos, Gustavo Luchi; Kondageski, Charles; Nunes, Jean Costa; Linhares, Marcelo Neves; Lin, Kátia; Latini, Alexandra Susana; Walz, Roger

    2016-04-01

    Mitochondrial respiratory chain complexes enzymatic (MRCCE) activities were successfully evaluated in frozen brain samples. Epilepsy surgery offers an ethical opportunity to study human brain tissue surgically removed to treat drug resistant epilepsies. Epilepsy surgeries are done with hemodynamic and laboratory parameters to maintain physiology, but there are no studies analyzing the association among these parameters and MRCCE activities in the human brain tissue. We determined the intra-operative parameters independently associated with MRCCE activities in middle temporal neocortex (Cx), amygdala (AMY) and head of hippocampus (HIP) samples of patients (n = 23) who underwent temporal lobectomy using multiple linear regressions. MRCCE activities in Cx, AMY and HIP are differentially associated to trans-operative mean arterial blood pressure, O2 saturation, hemoglobin, and anesthesia duration to time of tissue sampling. The time-course between the last seizure occurrence and tissue sampling as well as the sample storage to biochemical assessments were also associated with enzyme activities. Linear regression models including these variables explain 13-17 % of MRCCE activities and show a moderate to strong effect (r = 0.37-0.82). Intraoperative hemodynamic and laboratory parameters as well as the time from last seizure to tissue sampling and storage time are associated with MRCCE activities in human samples from the Cx, AMYG and HIP. Careful control of these parameters is required to minimize confounding biases in studies using human brain samples collected from elective neurosurgery.

  19. Validation of the total organic carbon (TOC) swab sampling and test method.

    PubMed

    Glover, Chris

    2006-01-01

    For cleaning validation purposes, the combination of swab sampling and the total organic carbon (TOC) test method provides a useful mechanism to monitor the cleanliness of equipment surfaces. The TOC test method is an ideal choice for monitoring carbon-containing residuals. Sample and test method validation "TOC Swabbing Method Validation" BV-000-BC-078-01, Bayer Healthcare, proved quantifiable recovery of albumin down to 25 microg. The validation characteristics included accuracy, repeatability and intermediate precision, specificity, linearity, assay range, detection and quantitation limit, and robustness.

  20. Sampling and analysis method for measuring airborne coal dust mass in mixtures with limestone (rock) dust

    PubMed Central

    Barone, T. L.; Patts, J. R.; Janisko, S. J.; Colinet, J. F.; Patts, L. D.; Beck, T. W.; Mischler, S. E.

    2016-01-01

    Airborne coal dust mass measurements in underground bituminous coal mines can be challenged by the presence of airborne limestone dust, which is an incombustible dust applied to prevent the propagation of dust explosions. To accurately measure the coal portion of this mixed airborne dust, the National Institute for Occupational Safety and Health (NIOSH) developed a sampling and analysis protocol that used a stainless steel cassette adapted with an isokinetic inlet and the low temperature ashing (LTA) analytical method. The Mine Safety and Health Administration (MSHA) routinely utilizes this LTA method to quantify the incombustible content of bulk dust samples collected from the roof, floor, and ribs of mining entries. The use of the stainless steel cassette with isokinetic inlet allowed NIOSH to adopt the LTA method for the analysis of airborne dust samples. Mixtures of known coal and limestone dust masses were prepared in the laboratory, loaded into the stainless steel cassettes, and analyzed to assess the accuracy of this method. Coal dust mass measurements differed from predicted values by an average of 0.5%, 0.2%, and 0.1% for samples containing 20%, 91%, and 95% limestone dust, respectively. The ability of this method to accurately quantify the laboratory samples confirmed the validity of this method and allowed NIOSH to successfully measure the coal fraction of airborne dust samples collected in an underground coal mine. PMID:26618374

  1. Sampling and analysis method for measuring airborne coal dust mass in mixtures with limestone (rock) dust.

    PubMed

    Barone, T L; Patts, J R; Janisko, S J; Colinet, J F; Patts, L D; Beck, T W; Mischler, S E

    2016-01-01

    Airborne coal dust mass measurements in underground bituminous coal mines can be challenged by the presence of airborne limestone dust, which is an incombustible dust applied to prevent the propagation of dust explosions. To accurately measure the coal portion of this mixed airborne dust, the National Institute for Occupational Safety and Health (NIOSH) developed a sampling and analysis protocol that used a stainless steel cassette adapted with an isokinetic inlet and the low temperature ashing (LTA) analytical method. The Mine Safety and Health Administration (MSHA) routinely utilizes this LTA method to quantify the incombustible content of bulk dust samples collected from the roof, floor, and ribs of mining entries. The use of the stainless steel cassette with isokinetic inlet allowed NIOSH to adopt the LTA method for the analysis of airborne dust samples. Mixtures of known coal and limestone dust masses were prepared in the laboratory, loaded into the stainless steel cassettes, and analyzed to assess the accuracy of this method. Coal dust mass measurements differed from predicted values by an average of 0.5%, 0.2%, and 0.1% for samples containing 20%, 91%, and 95% limestone dust, respectively. The ability of this method to accurately quantify the laboratory samples confirmed the validity of this method and allowed NIOSH to successfully measure the coal fraction of airborne dust samples collected in an underground coal mine.

  2. A Predictive Model for Toxicity Effects Assessment of Biotransformed Hepatic Drugs Using Iterative Sampling Method

    PubMed Central

    Tharwat, Alaa; Moemen, Yasmine S.; Hassanien, Aboul Ella

    2016-01-01

    Measuring toxicity is one of the main steps in drug development. Hence, there is a high demand for computational models to predict the toxicity effects of the potential drugs. In this study, we used a dataset, which consists of four toxicity effects:mutagenic, tumorigenic, irritant and reproductive effects. The proposed model consists of three phases. In the first phase, rough set-based methods are used to select the most discriminative features for reducing the classification time and improving the classification performance. Due to the imbalanced class distribution, in the second phase, different sampling methods such as Random Under-Sampling, Random Over-Sampling and Synthetic Minority Oversampling Technique are used to solve the problem of imbalanced datasets. ITerative Sampling (ITS) method is proposed to avoid the limitations of those methods. ITS method has two steps. The first step (sampling step) iteratively modifies the prior distribution of the minority and majority classes. In the second step, a data cleaning method is used to remove the overlapping that is produced from the first step. In the third phase, Bagging classifier is used to classify an unknown drug into toxic or non-toxic. The experimental results proved that the proposed model performed well in classifying the unknown samples according to all toxic effects in the imbalanced datasets. PMID:27934950

  3. Efficient free energy calculations by combining two complementary tempering sampling methods.

    PubMed

    Xie, Liangxu; Shen, Lin; Chen, Zhe-Ning; Yang, Mingjun

    2017-01-14

    Although energy barriers can be efficiently crossed in the reaction coordinate (RC) guided sampling, this type of method suffers from identification of the correct RCs or requirements of high dimensionality of the defined RCs for a given system. If only the approximate RCs with significant barriers are used in the simulations, hidden energy barriers with small to medium height would exist in other degrees of freedom (DOFs) relevant to the target process and consequently cause the problem of insufficient sampling. To address the sampling in this so-called hidden barrier situation, here we propose an effective approach to combine temperature accelerated molecular dynamics (TAMD), an efficient RC-guided sampling method, with the integrated tempering sampling (ITS), a generalized ensemble sampling method. In this combined ITS-TAMD method, the sampling along the major RCs with high energy barriers is guided by TAMD and the sampling of the rest of the DOFs with lower but not negligible barriers is enhanced by ITS. The performance of ITS-TAMD to three systems in the processes with hidden barriers has been examined. In comparison to the standalone TAMD or ITS approach, the present hybrid method shows three main improvements. (1) Sampling efficiency can be improved at least five times even if in the presence of hidden energy barriers. (2) The canonical distribution can be more accurately recovered, from which the thermodynamic properties along other collective variables can be computed correctly. (3) The robustness of the selection of major RCs suggests that the dimensionality of necessary RCs can be reduced. Our work shows more potential applications of the ITS-TAMD method as the efficient and powerful tool for the investigation of a broad range of interesting cases.

  4. Arsenic speciation in marine product samples: comparison of extraction-HPLC method and digestion-cryogenic trap method.

    PubMed

    Geng, Wenhua; Komine, Rieko; Ohta, Toshiharu; Nakajima, Tsunenori; Takanashi, Hirokazu; Ohki, Akira

    2009-07-15

    For the arsenic speciation in marine product samples, two types of pretreatment-analysis combination were compared. One is the combination of solvent extraction and high performance liquid chromatography (HPLC) followed by a highly sensitive arsenic detection, while the other is the combination of alkaline digestion and cryogenic trap (CT) method followed by a highly sensitive arsenic detection. For six certified reference materials (CRMs) of marine animal samples, the concentrations of arsenobetaine (AsB) obtained from the extraction-HPLC method were very consistent with those of trimethylated arsenic species measured by the digestion-CT method. For four seaweed samples, the determination of three arsenosugars (Sugar-1, Sugar-2, and Sugar-3) was favorably carried out by the extraction-HPLC method. Those seaweed samples were also subjected to the digestion-CT method, and the amounts of dimethylated arsenic species measured by the method were approximately equal to the sum of the amounts of dimethylarsinic acid (DMAA) and three arsenosugars (Sugar-1+Sugar-2+Sugar-3) obtained from the extraction-HPLC method.

  5. Systems and methods for laser assisted sample transfer to solution for chemical analysis

    DOEpatents

    Van Berkel, Gary J.; Kertesz, Vilmos; Ovchinnikova, Olga S.

    2014-06-03

    Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

  6. Systems and methods for laser assisted sample transfer to solution for chemical analysis

    DOEpatents

    Van Berkel, Gary J; Kertesz, Vilmos; Ovchinnikova, Olga S

    2013-08-27

    Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

  7. Systems and methods for laser assisted sample transfer to solution for chemical analysis

    DOEpatents

    Van Berkel, Gary J.; Kertesz, Vilmos; Ovchinnikova, Olga S.

    2015-09-29

    Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

  8. Preparation of the components of the modified method 5 (method 0010) sampling train for analysis by SW-846 method 8270. Report for December 1992-December 1993

    SciTech Connect

    McGaughey, J.F.; Merrill, R.G.; Bursey, J.T.; Wagoner, D.E.; Jackson, M.D.

    1993-12-01

    In a field evaluation study for semivolatile halogenated organic compounds listed in Title III of the Clean Air Act Amendments of 1990, dynamic spiking experiments using a liquid solution were performed in the field. Two of four quadruple sampling trains were spiked for eight sampling runs. Method 0010 train components were prepared and analyzed in three parts: filter/front halt rinse, XAD-2 resin, and condensate/condensate rinse. Because the results were at variance with results obtained for analytes spiked in laboratory studies and a previous field study, the sample preparation process was investigated in detail. Sample preparation procedures had followed Method 0010, but use of some procedures which were not specifically prohibited by Method 0010 had depressed compound recoveries. To ensure that the sample preparation procedures for Method 0010 train components were clear and unamibiguous, a new protocol to address preparation of Method 0010 train components for Method 8270 analysis was written.

  9. Method and apparatus for the preparation of liquid samples for determination of boron

    DOEpatents

    Siemer, Darryl D.

    1986-03-04

    A method and apparatus for the preparation of a liquid sample for the quantitative determination of boron by flame photometry. The sample is combined in a vessel with sulfuric acid, and an excess of methanol is added thereto. The methanol reacts with any boron present in the sample to form trimethyl borate which is volatilized by the heat of reaction between the excess methanol and sulfuric acid. The volatilized trimethyl borate is withdrawn from the vessel by either a partial vacuum or a positive pressure and is rapidly transferred to a standard flame photometer. The method is free of interference from typical boron concomitants.

  10. Method and apparatus for the preparation of liquid samples for determination of boron

    DOEpatents

    Siemer, Darryl D.

    1986-01-01

    A method and apparatus for the preparation of a liquid sample for the quantitative determination of boron by flame photometry. The sample is combined in a vessel with sulfuric acid, and an excess of methanol is added thereto. The methanol reacts with any boron present in the sample to form trimethyl borate which is volatilized by the heat of reaction between the excess methanol and sulfuric acid. The volatilized trimethyl borate is withdrawn from the vessel by either a partial vacuum or a positive pressure and is rapidly transferred to a standard flame photometer. The method is free of interference from typical boron concomitants.

  11. Method and apparatus for the preparation of liquid samples for determination of boron

    DOEpatents

    Siemer, D.D.

    A method and apparatus are described for the preparation of a liquid sample for the quantitative determination of boron by flame photometry. The sample is combined in a vessel with sulfuric acid, and an excess of methanol is added thereto. The methanol reacts with any boron present in the sample to form trimethyl borate which is volatilized by the heat of reaction between the excess methanol and sulfuric acid. The volatilized trimethyl borate is withdrawn from the vessel by either a partial vacuum or a positive pressure and is rapidly transferred to a standard flame photometer. The method is free of interference from typical boron concomitants.

  12. Method for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein

    DOEpatents

    Sinha, Dipen N.; Anthony, Brian W.

    1997-01-01

    A method for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein. A direct correlation between the octane rating of gasoline and the frequency of corresponding acoustic resonances therein has been experimentally observed. Therefore, the octane rating of a gasoline sample can be directly determined through speed of sound measurements instead of by the cumbersome process of quantifying the knocking quality of the gasoline. Various receptacle geometries and construction materials may be employed. Moreover, it is anticipated that the measurements can be performed on flowing samples in pipes, thereby rendering the present method useful in refineries and distilleries.

  13. Method for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein

    DOEpatents

    Sinha, D.N.; Anthony, B.W.

    1997-02-25

    A method is described for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein. A direct correlation between the octane rating of gasoline and the frequency of corresponding acoustic resonances therein has been experimentally observed. Therefore, the octane rating of a gasoline sample can be directly determined through speed of sound measurements instead of by the cumbersome process of quantifying the knocking quality of the gasoline. Various receptacle geometries and construction materials may be employed. Moreover, it is anticipated that the measurements can be performed on flowing samples in pipes, thereby rendering the present method useful in refineries and distilleries. 3 figs.

  14. Two media method for gamma ray attenuation coefficient measurement of archaeological ceramic samples

    PubMed

    Cunha e Silva RM; Appoloni; Parreira; Espinoza-Quinones; Coimbra; Aragao

    2000-12-01

    This work reports the application of an alternative methodology for the linear attenuation coefficient determination of irregular shape samples, in such a way that it is not necessary to know the sample thickness. Based on this method, indigenous archaeological ceramic fragments from the region of Londrina, north of Parana State in Brazil, were studied. On the other hand, theoretical mass attenuation coefficient values were determined with the XCOM computer code. With the results obtained, it was concluded that the two media method works very well for the linear attenuation coefficient measurement of irregular-shaped ceramic samples, which makes it suitable, especially, for archaeometric studies.

  15. A novel method to handle the effect of uneven sampling effort in biodiversity databases.

    PubMed

    Pardo, Iker; Pata, María P; Gómez, Daniel; García, María B

    2013-01-01

    How reliable are results on spatial distribution of biodiversity based on databases? Many studies have evidenced the uncertainty related to this kind of analysis due to sampling effort bias and the need for its quantification. Despite that a number of methods are available for that, little is known about their statistical limitations and discrimination capability, which could seriously constrain their use. We assess for the first time the discrimination capacity of two widely used methods and a proposed new one (FIDEGAM), all based on species accumulation curves, under different scenarios of sampling exhaustiveness using Receiver Operating Characteristic (ROC) analyses. Additionally, we examine to what extent the output of each method represents the sampling completeness in a simulated scenario where the true species richness is known. Finally, we apply FIDEGAM to a real situation and explore the spatial patterns of plant diversity in a National Park. FIDEGAM showed an excellent discrimination capability to distinguish between well and poorly sampled areas regardless of sampling exhaustiveness, whereas the other methods failed. Accordingly, FIDEGAM values were strongly correlated with the true percentage of species detected in a simulated scenario, whereas sampling completeness estimated with other methods showed no relationship due to null discrimination capability. Quantifying sampling effort is necessary to account for the uncertainty in biodiversity analyses, however, not all proposed methods are equally reliable. Our comparative analysis demonstrated that FIDEGAM was the most accurate discriminator method in all scenarios of sampling exhaustiveness, and therefore, it can be efficiently applied to most databases in order to enhance the reliability of biodiversity analyses.

  16. A passive guard for low thermal conductivity measurement of small samples by the hot plate method

    NASA Astrophysics Data System (ADS)

    Jannot, Yves; Degiovanni, Alain; Grigorova-Moutiers, Veneta; Godefroy, Justine

    2017-01-01

    Hot plate methods under steady state conditions are based on a 1D model to estimate the thermal conductivity, using measurements of the temperatures T 0 and T 1 of the two sides of the sample and of the heat flux crossing it. To be consistent with the hypothesis of the 1D heat flux, either a hot plate guarded apparatus is used, or the temperature is measured at the centre of the sample. On one hand the latter method can be used only if the ratio thickness/width of the sample is sufficiently low and on the other hand the guarded hot plate method requires large width samples (typical cross section of 0.6  ×  0.6 m2). That is why both methods cannot be used for low width samples. The method presented in this paper is based on an optimal choice of the temperatures T 0 and T 1 compared to the ambient temperature T a, enabling the estimation of the thermal conductivity with a centered hot plate method, by applying the 1D heat flux model. It will be shown that these optimal values do not depend on the size or on the thermal conductivity of samples (in the range 0.015-0.2 W m-1 K-1), but only on T a. The experimental results obtained validate the method for several reference samples for values of the ratio thickness/width up to 0.3, thus enabling the measurement of the thermal conductivity of samples having a small cross-section, down to 0.045  ×  0.045 m2.

  17. Culture methods of allograft musculoskeletal tissue samples in Australian bacteriology laboratories.

    PubMed

    Varettas, Kerry

    2013-12-01

    Samples of allograft musculoskeletal tissue are cultured by bacteriology laboratories to determine the presence of bacteria and fungi. In Australia, this testing is performed by 6 TGA-licensed clinical bacteriology laboratories with samples received from 10 tissue banks. Culture methods of swab and tissue samples employ a combination of solid agar and/or broth media to enhance micro-organism growth and maximise recovery. All six Australian laboratories receive Amies transport swabs and, except for one laboratory, a corresponding biopsy sample for testing. Three of the 6 laboratories culture at least one allograft sample directly onto solid agar. Only one laboratory did not use a broth culture for any sample received. An international literature review found that a similar combination of musculoskeletal tissue samples were cultured onto solid agar and/or broth media. Although variations of allograft musculoskeletal tissue samples, culture media and methods are used in Australian and international bacteriology laboratories, validation studies and method evaluations have challenged and supported their use in recovering fungi and aerobic and anaerobic bacteria.

  18. PhyloChip™ microarray comparison of sampling methods used for coral microbial ecology

    USGS Publications Warehouse

    Kellogg, Christina A.; Piceno, Yvette M.; Tom, Lauren M.; DeSantis, Todd Z.; Zawada, David G.; Andersen, Gary L.

    2012-01-01

    Interest in coral microbial ecology has been increasing steadily over the last decade, yet standardized methods of sample collection still have not been defined. Two methods were compared for their ability to sample coral-associated microbial communities: tissue punches and foam swabs, the latter being less invasive and preferred by reef managers. Four colonies of star coral, Montastraea annularis, were sampled in the Dry Tortugas National Park (two healthy and two with white plague disease). The PhyloChip™ G3 microarray was used to assess microbial community structure of amplified 16S rRNA gene sequences. Samples clustered based on methodology rather than coral colony. Punch samples from healthy and diseased corals were distinct. All swab samples clustered closely together with the seawater control and did not group according to the health state of the corals. Although more microbial taxa were detected by the swab method, there is a much larger overlap between the water control and swab samples than punch samples, suggesting some of the additional diversity is due to contamination from water absorbed by the swab. While swabs are useful for noninvasive studies of the coral surface mucus layer, these results show that they are not optimal for studies of coral disease.

  19. New method to estimate the sample size for calculation of a proportion assuming binomial distribution.

    PubMed

    Vallejo, Adriana; Muniesa, Ana; Ferreira, Chelo; de Blas, Ignacio

    2013-10-01

    Nowadays the formula to calculate the sample size for estimate a proportion (as prevalence) is based on the Normal distribution, however it would be based on a Binomial distribution which confidence interval was possible to be calculated using the Wilson Score method. By comparing the two formulae (Normal and Binomial distributions), the variation of the amplitude of the confidence intervals is relevant in the tails and the center of the curves. In order to calculate the needed sample size we have simulated an iterative sampling procedure, which shows an underestimation of the sample size for values of prevalence closed to 0 or 1, and also an overestimation for values closed to 0.5. Attending to these results we proposed an algorithm based on Wilson Score method that provides similar values for the sample size than empirically obtained by simulation.

  20. [Sample preprocessing method for residual quinolones in honey using immunoaffinity resin].

    PubMed

    Ihara, Yoshiharu; Kato, Mihoko; Kodaira, Tsukasa; Itoh, Shinji; Terakawa, Mika; Horie, Masakazu; Saito, Koichi; Nakazawa, Hiroyuki

    2009-06-01

    A sample preparation method was developed for determination of quinolones in honey using immunoaffinity resin. For this purpose, an immunoaffinity resin for quinolones was prepared by coupling a quinolone-specific monoclonal antibody to agarose resin. Honey samples diluted with phosphate buffer were reacted with immunoaffinity resin. After the resin was washed, quinolones were eluted with glycine-HCl. Quinolones in the eluate were determined by HPLC with fluorescence detection. No interfering peak was found on the chromatograms of honey samples. The recoveries of quinolones from samples were over 70% at fortification levels of 20 ng/g (for norfloxacin, ciprofloxacin and enrofloxacin) and 10 ng/g (for danofloxacin). The quantification limits of quinolones were 2 ng/g. This sample preprocessing method using immunoaffinity resin was found to be effective and suitable for determining residual quinolones in honey.