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Sample records for rapid direct determination

  1. Rapid determination of nicotine in urine by direct thermal desorption ion trap mass spectrometry

    SciTech Connect

    Wise, M.B.; Ilgner, R.H.; Guerin, M.R.

    1990-01-01

    The measurement of nicotine and cotinine in physiological fluids (urine, blood serum, and saliva) is widely used as a means of assessing human exposure to environmental tobacco smoke (ETS). Although numerous analytical methods exist for these measurements, they generally involve extensive sample preparation which increases cost and decreases sample throughput. We report the use of thermal desorption directly into an ion trap mass spectrometer (ITMS) for the rapid determination of nicotine and cotinine in urine. A 1{mu}L aliquot of urine is injected into a specially designed inlet and flash vaporized directly into an ITMS through an open-split capillary restrictor interface. Isobutane chemical ionization is used to generate (M+H){sup +} ions of the analytes and collision induced dissociation is used to generate characteristic fragment ions which are used to confirm their identity. Quantification is achieved by integrating the ion current for the characteristic ions and comparing with an external working curve. Detection limits are approximately 50 pg per analyte and the sample turnaround time is approximately 3 minutes without the need for extensive sample preparation. 12 refs., 5 figs.

  2. A fluorescence-based method for rapid and direct determination of polybrominated diphenyl ethers in water

    DOE PAGESBeta

    Shan, Huimei; Liu, Chongxuan; Wang, Zheming; Ma, Teng; Shang, Jianying; Pan, Duoqiang

    2015-01-01

    A new method was developed for rapid and direct measurement of polybrominated diphenyl ethers (PBDEs) in aqueous samples using fluorescence spectroscopy. The fluorescence spectra of tri- to deca-BDE (BDE 28, 47, 99, 153, 190, and 209) commonly found in environment were measured at variable emission and excitation wavelengths. The results revealed that the PBDEs have distinct fluorescence spectral profiles and peak positions that can be exploited to identify these species and determine their concentrations in aqueous solutions. The detection limits as determined in deionized water spiked with PBDEs are 1.71-5.82 ng/L for BDE 28, BDE 47, BDE 190, and BDEmore » 209 and 45.55–69.95 ng/L for BDE 99 and BDE 153. The effects of environmental variables including pH, humic substance, and groundwater chemical composition on PBDEs measurements were also investigated. These environmental variables affected fluorescence intensity, but their effect can be corrected through linear additivity and separation of spectral signal contribution. Compared with conventional GC-based analytical methods, the fluorescence spectroscopy method is more efficient as it only uses a small amount of samples (2-4 mL), avoids lengthy complicated concentration and extraction steps, and has a low detection limit of a few ng/L.« less

  3. A Fluorescence-Based Method for Rapid and Direct Determination of Polybrominated Diphenyl Ethers in Water

    PubMed Central

    Shan, Huimei; Ma, Teng; Shang, Jianying; Pan, Duoqiang

    2015-01-01

    A new method was developed for rapid and direct measurement of polybrominated diphenyl ethers (PBDEs) in aqueous samples using fluorescence spectroscopy. The fluorescence spectra of tri- to deca-BDE (BDE 28, 47, 99, 153, 190, and 209) commonly found in environment were measured at variable emission and excitation wavelengths. The results revealed that the PBDEs have distinct fluorescence spectral profiles and peak positions that can be exploited to identify these species and determine their concentrations in aqueous solutions. The detection limits as determined in deionized water spiked with PBDEs are 1.71–5.82 ng/L for BDE 28, BDE 47, BDE 190, and BDE 209 and 45.55–69.95 ng/L for BDE 99 and BDE 153. The effects of environmental variables including pH, humic substance, and groundwater chemical composition on PBDEs measurements were also investigated. These environmental variables affected fluorescence intensity, but their effect can be corrected through linear additivity and separation of spectral signal contribution. Compared with conventional GC-based analytical methods, the fluorescence spectroscopy method is more efficient as it only uses a small amount of samples (2–4 mL), avoids lengthy complicated concentration and extraction steps, and has a low detection limit of a few ng/L. PMID:25705548

  4. A fluorescence-based method for rapid and direct determination of polybrominated diphenyl ethers in water

    SciTech Connect

    Shan, Huimei; Liu, Chongxuan; Wang, Zheming; Ma, Teng; Shang, Jianying; Pan, Duoqiang

    2015-01-01

    A new method was developed for rapid and direct measurement of polybrominated diphenyl ethers (PBDEs) in aqueous samples using fluorescence spectroscopy. The fluorescence spectra of tri- to deca-BDE (BDE 28, 47, 99, 153, 190, and 209) commonly found in environment were measured at variable emission and excitation wavelengths. The results revealed that the PBDEs have distinct fluorescence spectral profiles and peak positions that can be exploited to identify these species and determine their concentrations in aqueous solutions. The detection limits as determined in deionized water spiked with PBDEs are 1.71-5.82 ng/L for BDE 28, BDE 47, BDE 190, and BDE 209 and 45.55–69.95 ng/L for BDE 99 and BDE 153. The effects of environmental variables including pH, humic substance, and groundwater chemical composition on PBDEs measurements were also investigated. These environmental variables affected fluorescence intensity, but their effect can be corrected through linear additivity and separation of spectral signal contribution. Compared with conventional GC-based analytical methods, the fluorescence spectroscopy method is more efficient as it only uses a small amount of samples (2-4 mL), avoids lengthy complicated concentration and extraction steps, and has a low detection limit of a few ng/L.

  5. Rapid, accurate, and direct determination of total lycopene content in tomato paste

    NASA Astrophysics Data System (ADS)

    Bicanic, D.; Anese, M.; Luterotti, S.; Dadarlat, D.; Gibkes, J.; Lubbers, M.

    2003-01-01

    Lycopene that imparts red color to the tomato fruit is the most potent antioxidant among carotenes, an important nutrient and also used as a color ingredient in many food formulations. Since cooked and processed foods derived from tomatoes were shown to provide optimal lycopene boost, products such as paste, puree, juice, etc. are nowadays gaining popularity as dietary sources. The analysis of lycopene in tomato paste (partially dehydrated product prepared by vacuum concentrating tomato juice) is carried out using either high pressure liquid chromatography (HPLC), spectrophotometry, or by evaluating the color. The instability of lycopene during processes of extraction, etc., handling, and disposal of organic solvents makes the preparation of a sample for the analysis a delicate task. Despite a recognized need for accurate and rapid assessment of lycopene in tomato products no such method is available at present. The study described here focuses on a direct determination of a total lycopene content in different tomato pastes by means of the laser optothermal window (LOW) method at 502 nm. The concentration of lycopene in tomato paste ranged between 25 and 150 mg per 100 g product; the results are in excellent agreement with those obtained by spectrophotometry. The time needed to complete LOW analysis is very short, so that decomposition of pigment and the formation of artifacts are minimized. Preliminary results indicate a good degree of reproducibility making the LOW method suitable for routine assays of lycopene content in tomato paste.

  6. Direct and rapid determination of cotton maturity by FT-Mid-IR technique

    Technology Transfer Automated Retrieval System (TEKTRAN)

    FT-mid-IR (FT-MIR) spectra of seed and lint cottons were collected to explore the potential for the discrimination of immature cottons from mature ones and also for the determination of actual cotton maturity. Spectral features of immature and mature cottons revealed large differences in the 1200-90...

  7. Codeine-binding RNA aptamers and rapid determination of their binding constants using a direct coupling surface plasmon resonance assay

    PubMed Central

    Win, Maung Nyan; Klein, Joshua S.; Smolke, Christina D.

    2006-01-01

    RNA aptamers that bind the opium alkaloid codeine were generated using an iterative in vitro selection process. The binding properties of these aptamers, including equilibrium and kinetic rate constants, were determined through a rapid, high-throughput approach using surface plasmon resonance (SPR) analysis to measure real-time binding. The approach involves direct coupling of the target small molecule onto a sensor chip without utilization of a carrier protein. Two highest binding aptamer sequences, FC5 and FC45 with Kd values of 2.50 and 4.00 μM, respectively, were extensively studied. Corresponding mini-aptamers for FC5 and FC45 were subsequently identified through the described direct coupling Biacore assays. These assays were also employed to confirm the proposed secondary structures of the mini-aptamers. Both aptamers exhibit high specificity to codeine over morphine, which differs from codeine by a methyl group. Finally, the direct coupling method was demonstrated to eliminate potential non-specific interactions that may be associated with indirect coupling methods in which protein linkers are commonly employed. Therefore, in addition to presenting the first RNA aptamers to a subclass of benzylisoquinoline alkaloid molecules, this work highlights a method for characterizing small molecule aptamers that is more robust, precise, rapid and high-throughput than other commonly employed techniques. PMID:17038331

  8. A rapid, direct method for determining organic sulfur content in coal

    NASA Astrophysics Data System (ADS)

    Davies, T. D.; Raymond, R.

    1981-02-01

    A recently develped analytical method using the EPM (electron probe microanalyzer) measures organic sulfur directly and avoids the uncertainty of calculating organic sulfur content by difference. Analysis of 18 different coals (from 10 states, ranging in rank from subbituminous C to low vol. bituminous, and in age from Pennsylvania to Palaeocene) shows that organic sulfur contents of coals can be calculated from the organic sulfur contents of the vitrinite in the coals. This empirical relationship exists because vitrinite is the dominant maceral type is most coals and generally has a sulfur composition intermediate between exinites and inertinites. For EPM organic sulfur analysis, representative samples (-20 to -60 mesh) are potted in 1″ diameter epoxy pellets, polished and carbon coated. Vitrinite grains are identified during analysis by shape and texture, with results equivalent to oil immersion, reflectance techniques. According to t-statistics, analyzing 15 vitrinite grains achieves a maximum variability of less than 0.20 wt % from the ''true'' organic sulfur content of coals containing less than 2.00 wt % organic sulfur. Neither operator experience nor variation in coal composition and rank appear to bias results. A mojor problem with the EPM technique has been finding a suitable EPM sulfur standard. Recently, in cooperation with L. A. Harris, Oak Ridge National Laboratory, we have prepared a good standard, derived from a petroleum coke, which is stable under an electron beam and contains a uniform sulfur content.

  9. Rapid and direct electrochemical determination of Ni(II) in industrial discharge water.

    PubMed

    Ferancová, Adriana; Hattuniemi, Maarit K; Sesay, Adama M; Räty, Jarkko P; Virtanen, Vesa T

    2016-04-01

    Industrial water contains a number of contaminants, such as organic pollutants and heavy metals, which can significantly affect the quality of soil, ground and environmental waters. We have successfully optimized and tested an electrochemical method and sensor modified with dimethylglyoxime for monitoring of nickel(II). The detection limit was 0.03mg/L and determination limit was 0.09mg/L. Linear concentration range was observed from 0.06 to 0.5mg/L Ni(II) and it is suitable for the analysis of environmental waters. The effect of all parameters important for on-site measurements (such as interferences, presence of dissolved oxygen, temperature) was investigated and considered in the analysis of mine discharge water. Water samples were analyzed without any pretreatment or filtration. A low level of error (5.6%) was observed for analysis demonstrating the usability of the optimized sensor and method for on-site measurements. PMID:26686524

  10. [Rapid determination of trace iodate using monolithic column ion-pair chromatography coupled with direct conductivity detection].

    PubMed

    Liu, Yuzhen; Yu, Hong; Li, Siwen

    2011-10-01

    A method was developed on a monolithic column for the fast determination of trace iodate (IO(3)- ) by ion-pair chromatography with direct conductivity detection. The analytes were separated using a mobile phase of tetrabutylammonium hydroxide (TBA)-phthalic acid-acetonitrile on a reversed-phase silica-based monolithic column. The effects of eluent, flow rate and column temperature on the retention of iodate were investigated. The optimized chromatographic conditions for the determination of the anion were as follows: 0. 25 mmol/L TBA-0. 18 mmol/L phthalic acid-3% acetonitrile (pH 5.5) as mobile phase, a flow rate of 4.0 mL/min and a column temperature of 30 degrees C. Under the optimal conditions, retention time of iodate was less than 0. 5 min and the baseline separation of iodate was achieved without any interference by other anions (Cl-, NO , SO4(2)-, I- ). The detection limit (S/N= 3) was 0.36 mg/L for IO(3)- . Relative standard deviation (RSD, n = 5) of chromatographic peak area and retention time were 0. 35% and 0. 28%, respectively. The proposed method was applied to the determination of trace iodate in iodized medicine. The spiked recovery of iodate was 96. 4%. The method is rapid, simple, accurate, reliable, and practical. PMID:22268363

  11. Rapid and direct determination of glyphosate, glufosinate, and aminophosphonic acid by online preconcentration CE with contactless conductivity detection.

    PubMed

    See, Hong Heng; Hauser, Peter C; Ibrahim, Wan Aini Wan; Sanagi, Mohd Marsin

    2010-01-01

    Rapid and direct online preconcentration followed by CE with capacitively coupled contactless conductivity detection (CE-C(4)D) is evaluated as a new approach for the determination of glyphosate, glufosinate (GLUF), and aminophosphonic acid (AMPA) in drinking water. Two online preconcentration techniques, namely large volume sample stacking without polarity switching and field-enhanced sample injection, coupled with CE-C(4)D were successfully developed and optimized. Under optimized conditions, LODs in the range of 0.01-0.1 microM (1.7-11.1 microg/L) and sensitivity enhancements of 48- to 53-fold were achieved with the large volume sample stacking-CE-C(4)D method. By performing the field-enhanced sample injection-CE-C(4)D procedure, excellent LODs down to 0.0005-0.02 microM (0.1-2.2 microg/L) as well as sensitivity enhancements of up to 245- to 1002-fold were obtained. Both techniques showed satisfactory reproducibility with RSDs of peak height of better than 10%. The newly established approaches were successfully applied to the analysis of glyphosate, glufosinate, and aminophosphonic acid in spiked tap drinking water. PMID:20119968

  12. Rapid determination of benzodiazepines, zolpidem and their metabolites in urine using direct injection liquid chromatography-tandem mass spectrometry.

    PubMed

    Jeong, Yu-Dong; Kim, Min Kyung; Suh, Sung Ill; In, Moon Kyo; Kim, Jin Young; Paeng, Ki-Jung

    2015-12-01

    Benzodiazepines and zolpidem are generally prescribed as sedative, hypnotics, anxiolytics or anticonvulsants. These drugs, however, are frequently misused in drug-facilitated crime. Therefore, a rapid and simple liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for identification and quantification of benzodiazepines, zolpidem and their metabolites in urine using deuterium labeled internal standards (IS). Urine samples (120 μL) mixed with 80 μL of the IS solution were centrifuged. An aliquot (5 μL) of the sample solution was directly injected into the LC-MS/MS system for analysis. The mobile phases consisted of water and acetonitrile containing 2mM ammonium trifluoroacetate and 0.2% acetic acid. The analytical column was a Zorbax SB-C18 (100 mm × 2.1 mm i.d., 3.5 μm, Agilent). The separation and detection of 18 analytes were achieved within 10 min. Calibration curves were linear over the concentration ranges of 0.5-20 ng/mL (zolpidem), 1.0-40 ng/mL (flurazepam and temazepam), 2.5-100 ng/mL (7-aminoclonazepam, 1-hydroxymidazolam, midazolam, flunitrazepam and alprazolam), 5.0-200 ng/mL (zolpidem phenyl-4-carboxylic acid, α-hydroxyalprazolam, oxazepam, nordiazepam, triazolam, diazepam and α-hydroxytriazolam), 10-400 ng/mL (lorazepam and desalkylflurazepam) and 10-100 ng/mL (N-desmethylflunitrazepam) with the coefficients of determination (r(2)) above 0.9971. The dilution integrity of the analytes was examined for supplementation of short linear range. Dilution precision and accuracy were tested using two, four and ten-folds dilutions and they ranged from 3.7 to 14.4% and -12.8 to 12.5%, respectively. The process efficiency for this method was 63.0-104.6%. Intra- and inter-day precisions were less than 11.8% and 9.1%, while intra- and inter-day accuracies were less than -10.0 to 8.2%, respectively. The lower limits of quantification were lower than 10 ng/mL for each analyte. The applicability of the developed method was successfully

  13. Rapid Determination of Clenbuterol in Pork by Direct Immersion Solid-Phase Microextraction Coupled with Gas Chromatography-Mass Spectrometry.

    PubMed

    Ye, Diru; Wu, Susu; Xu, Jianqiao; Jiang, Ruifen; Zhu, Fang; Ouyang, Gangfeng

    2016-02-01

    Direct immersion solid-phase microextraction (DI-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was developed for rapid analysis of clenbuterol in pork for the first time. In this work, a low-cost homemade 44 µm polydimethylsiloxane (PDMS) SPME fiber was employed to extract clenbuterol in pork. After extraction, derivatization was performed by suspending the fiber in the headspace of the 2 mL sample vial saturated with a vapor of 100 µL hexamethyldisilazane. Lastly, the fiber was directly introduced to GC-MS for analysis. All parameters that influenced absorption (extraction time), derivatization (derivatization reagent, time and temperature) and desorption (desorption time) were optimized. Under optimized conditions, the method offered a wide linear range (10-1000 ng g(-1)) and a low detection limit (3.6 ng g(-1)). Finally, the method was successfully applied in the analysis of pork from the market, and recoveries of the method for spiked pork were 97.4-105.7%. Compared with the traditional solvent extraction method, the proposed method was much cheaper and fast. PMID:26306572

  14. Development of a rapid and direct method for the determination of organic acids in peach fruit using LC-ESI-MS.

    PubMed

    Sandín-España, Pilar; Mateo-Miranda, M; López-Goti, Carmen; De Cal, A; Alonso-Prados, José Luis

    2016-02-01

    An accurate, simple and rapid liquid chromatography mass spectrometry method for the determination of organic acids in peach fruit has been developed. Direct injection and sample clean-up with a mixed-mode sorbent was compared. The best results for the determination of gluconic, oxalic, malic, citric and fumaric acids were obtained with only a simple dilution and filtration step, and nylon filters should be avoided since some organic acids are retained by them. It is the first time that gluconic acid has been determined in peach fruit. Different parameters involved in the separation and detection process have been optimized. Since matrix effects were observed in the peach commodity, organic acids were quantified by the standard addition method. All validation parameters of the method were found acceptable of all organic acids. Finally, the method was successfully applied to the analysis of samples of peach from two cultivars. PMID:26304346

  15. Development of Fourier transform infrared Spectroscopy in direct, non-destructive, and rapid determination of cotton fiber maturity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    FTIR spectra of seed and lint cottons were collected to explore the potential for the discrimination of immature cottons from mature ones and also for the determination of actual cotton maturity. Spectral features of immature and mature cottons revealed large differences in the 1200-900 cm-1 region,...

  16. Development of simple algorithm for direct and rapid determination of cotton maturity from FT-IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, Yongliang; Thibodeaux, Devron; Gamble, Gary R.

    2011-06-01

    Fourier transform infrared (FT-IR) spectra of seed and lint cottons were collected to explore the potential for the discrimination of immature cottons from mature ones and also for the determination of actual cotton maturity. Spectral features of immature and mature cottons revealed large differences in the 1200-900 cm-1 region, and such spectral distinctions formed the basis on which to develop simple three-band ratio algorithm for classification analysis. Next, an additional formula was created to assess the degree of cotton fiber maturity by converting the three-band ratios into an appropriate FT-IR maturity (MIR) index. Furthermore, the MIR index was compared with parameters derived from traditional image analysis (IA) and advanced fiber information system (AFIS) measurements. Results indicated strong correlations (R2 > 0.89) between MIR and MAFIS and between MIR and MIA among either International Cotton Calibration (ICC) standards or selected cotton maturity references. On the other hand, low correlations between the pairs were observed among regular cotton fibers, which likely resulted from the heterogeneous distribution of structural, physical, and chemical characteristics in cotton fibers and subsequent different sampling specimens for individual and independent measurement.

  17. A simple and rapid method for direct determination of Al(III) based on the enhanced resonance Rayleigh scattering of hemin-functionalized graphene-Al(III) system

    NASA Astrophysics Data System (ADS)

    Ling, Yu; Chen, Ling Xiao; Dong, Jiang Xue; Li, Nian Bing; Luo, Hong Qun

    2016-03-01

    A novel method for direct determination of Al(III) by using hemin-functionalized graphene (H-GO) has been established based on the enhancement of resonance Rayleigh scattering (RRS) intensity. The characteristics of RRS spectra, the optimum reaction conditions, and the reaction mechanism have been investigated. In this experiment, the Al(III) would exist in sol-gel Al(OH)3 species under the condition of pH 5.9 in aqueous solutions. When H-GO existed in the solution, the sol-gel Al(OH)3 would react with H-GO and result in enhancement of RRS intensity, owing to the enhanced hydrophobicity of H-GO surface. Therefore, a simple and rapid sensor for Al(III) was developed. The increased intensity of RRS is directly proportional to the concentration of Al(III) in the range of 10 nM-6 μM, along with a detection limit of 0.87 nM. Moreover, the sensor has been applied to determination of Al(III) concentration in real water and aspirin tablet samples with satisfactory results. Therefore, the proposed method is promising as an effective means for selective and sensitive determination of Al(III).

  18. Staph ID/R: a Rapid Method for Determining Staphylococcus Species Identity and Detecting the mecA Gene Directly from Positive Blood Culture

    PubMed Central

    Pasko, Chris; Dunn, John; Jaeckel, Heidi; Nieuwlandt, Dan; Weed, Diane; Woodruff, Evelyn; Zheng, Xiaotian

    2012-01-01

    Rapid diagnosis of staphylococcal bacteremia directs appropriate antimicrobial therapy, leading to improved patient outcome. We describe herein a rapid test (<75 min) that can identify the major pathogenic strains of Staphylococcus to the species level as well as the presence or absence of the methicillin resistance determinant gene, mecA. The test, Staph ID/R, combines a rapid isothermal nucleic acid amplification method, helicase-dependent amplification (HDA), with a chip-based array that produces unambiguous visible results. The analytic sensitivity was 1 CFU per reaction for the mecA gene and was 1 to 250 CFU per reaction depending on the staphylococcal species present in the positive blood culture. Staph ID/R has excellent specificity as well, with no cross-reactivity observed. We validated the performance of Staph ID/R by testing 104 frozen clinical positive blood cultures and comparing the results with rpoB gene or 16S rRNA gene sequencing for species identity determinations and mecA gene PCR to confirm mecA gene results. Staph ID/R agreed with mecA gene PCR for all samples and agreed with rpoB/16S rRNA gene sequencing in all cases except for one sample that contained a mixture of two staphylococcal species, one of which Staph ID/R correctly identified, for an overall agreement of 99.0% (P < 0.01). Staph ID/R could potentially be used to positively affect patient management for Staphylococcus-mediated bacteremia. PMID:22170912

  19. Sorptive thin film microextraction followed by direct solid state spectrofluorimetry: A simple, rapid and sensitive method for determination of carvedilol in human plasma.

    PubMed

    Karimi, Shima; Talebpour, Zahra; Adib, Noushin

    2016-06-14

    A poly acrylate-ethylene glycol (PA-EG) thin film is introduced for the first time as a novel polar sorbent for sorptive extraction method coupled directly to solid-state spectrofluorimetry without the necessity of a desorption step. The structure, polarity, fluorescence property and extraction performance of the developed thin film were investigated systematically. Carvedilol was used as the model analyte to evaluate the proposed method. The entire procedure involved one-step extraction of carvedilol from plasma using PA-EG thin film sorptive phase without protein precipitation. Extraction variables were studied in order to establish the best experimental conditions. Optimum extraction conditions were the followings: stirring speed of 1000 rpm, pH of 6.8, extraction temperature of 60 °C, and extraction time of 60 min. Under optimal conditions, extraction of carvedilol was carried out in spiked human plasma; and the linear range of calibration curve was 15-300 ng mL(-1) with regression coefficient of 0.998. Limit of detection (LOD) for the method was 4.5 ng mL(-1). The intra- and inter-day accuracy and precision of the proposed method were evaluated in plasma sample spiked with three concentration levels of carvedilol; yielding a recovery of 91-112% and relative standard deviation of less than 8%, respectively. The established procedure was successfully applied for quantification of carvedilol in plasma sample of a volunteer patient. The developed PA-EG thin film sorptive phase followed by solid-state spectrofluorimetric method provides a simple, rapid and sensitive approach for the analysis of carvedilol in human plasma. PMID:27181643

  20. Rapid Decimation for Direct Volume Rendering

    NASA Technical Reports Server (NTRS)

    Gibbs, Jonathan; VanGelder, Allen; Verma, Vivek; Wilhelms, Jane

    1997-01-01

    An approach for eliminating unnecessary portions of a volume when producing a direct volume rendering is described. This reduction in volume size sacrifices some image quality in the interest of rendering speed. Since volume visualization is often used as an exploratory visualization technique, it is important to reduce rendering times, so the user can effectively explore the volume. The methods presented can speed up rendering by factors of 2 to 3 with minor image degradation. A family of decimation algorithms to reduce the number of primitives in the volume without altering the volume's grid in any way is introduced. This allows the decimation to be computed rapidly, making it easier to change decimation levels on the fly. Further, because very little extra space is required, this method is suitable for the very large volumes that are becoming common. The method is also grid-independent, so it is suitable for multiple overlapping curvilinear and unstructured, as well as regular, grids. The decimation process can proceed automatically, or can be guided by the user so that important regions of the volume are decimated less than unimportant regions. A formal error measure is described based on a three-dimensional analog of the Radon transform. Decimation methods are evaluated based on this metric and on direct comparison with reference images.

  1. Rapid and simultaneous determination of tetrafluoroborate, thiocyanate and hexafluorophosphate by high-performance liquid chromatography using a monolithic column and direct conductivity detection.

    PubMed

    Yang, Ling; Yu, Hong; Wang, Yaqin

    2010-01-01

    A method was developed for fast and simultaneous determination of tetrafluoroborate (BF(4)(-)), thiocyanate (SCN(-)) and hexafluorophosphate (PF(6)(-)) by high-performance liquid chromatography using a silica-based monolithic column and direct (non-suppressed) conductivity detection. Chromatographic separation was performed on a Chromolith Speed ROD RP-18e column with tetrabutylammonium hydroxide (TBA) + citric acid + acetonitrile as eluent. The effects of the types of eluent, TBA concentration, acetonitrile volume fraction, eluent pH, column temperature and flow rate on the retention of anions were investigated. The optimized chromatographic conditions were selected. Under the optimal conditions, the baseline separation of BF(4)(-), SCN(-) and PF(6)(-) was achieved without any interference by other anions (F(-), Cl(-), Br(-), I(-), NO(3)(-), ClO(3)(-) and SO(4)(2-)). The detection limit (S/N = 3) was 0.42, 0.46 and 1.42 mg L(-1) for BF(4)(-), SCN(-) and PF(6)(-), respectively. The present method was successfully applied to the determination of BF(4)(-), SCN(-) and PF(6)(-) in ionic liquids. PMID:20702939

  2. RAPID DETERMINATION OF RADIOSTRONTIUM IN SEAWATER SAMPLES

    SciTech Connect

    Maxwell, S.

    2013-01-16

    A new method for the determination of radiostrontium in seawater samples has been developed at the Savannah River National Laboratory (SRNL) that allows rapid preconcentration and separation of strontium and yttrium isotopes in seawater samples for measurement. The new SRNL method employs a novel and effective pre-concentration step that utilizes a blend of calcium phosphate with iron hydroxide to collect both strontium and yttrium rapidly from the seawater matrix with enhanced chemical yields. The pre-concentration steps, in combination with rapid Sr Resin and DGA Resin cartridge separation options using vacuum box technology, allow seawater samples up to 10 liters to be analyzed. The total {sup 89}Sr + {sup 90}Sr activity may be determined by gas flow proportional counting and recounted after ingrowth of {sup 90}Y to differentiate {sup 89}Sr from {sup 90}Sr. Gas flow proportional counting provides a lower method detection limit than liquid scintillation or Cerenkov counting and allows simultaneous counting of samples. Simultaneous counting allows for longer count times and lower method detection limits without handling very large aliquots of seawater. Seawater samples up to 6 liters may be analyzed using Sr Resin for {sup 89}Sr and {sup 90}Sr with a Minimum Detectable Activity (MDA) of 1-10 mBq/L, depending on count times. Seawater samples up to 10 liters may be analyzed for {sup 90}Sr using a DGA Resin method via collection and purification of {sup 90}Y only. If {sup 89}Sr and other fission products are present, then {sup 91}Y (beta energy 1.55 MeV, 58.5 day half-life) is also likely to be present. {sup 91}Y interferes with attempts to collect {sup 90}Y directly from the seawater sample without initial purification of Sr isotopes first and {sup 90}Y ingrowth. The DGA Resin option can be used to determine {sup 90}Sr, and if {sup 91}Y is also present, an ingrowth option with using DGA Resin again to collect {sup 90}Y can be performed. An MDA for {sup 90}Sr of <1 m

  3. Morphological instability in rapid directional solidification

    NASA Technical Reports Server (NTRS)

    Merchant, G. J.; Davis, S. H.

    1990-01-01

    Mullins and Sekerka (1964) showed for fixed temperature gradient that the planar interface is linearly stable for all pulling speeds V above some critical value, the absolute stability limit. Near this limit, where solidification rates are rapid, the assumption of local equilibrium at the interface may be violated. Here, nonequilibrium effects are incorporated into a linear stability analysis of the planar front by allowing the segregation coefficient and interface temperature to depend on V in a thermodynamically consistent way. The absolute stability limit of the cellular mode is modified. A new oscillatory state is formed which, in the absence of latent heat, has a critical wavenumber of zero; by itself this instability would lead to the formation of solute bands in the solid. This mode has its own absolute-stability limit determined by solute trapping and kinetics. Under certain conditions, there exists a window of stability above the steady absolute-stability boundary and below the oscillatory-stability boundary; here the planar segregation-free state is restabilized.

  4. Development of Simple Algorithms in Direct, Non-destructive, and Rapid Determination of Cotton Fiber Maturity from FT-IR/ATR Spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    FT-IR/ATR spectra of seed and lint cottons were collected to explore the potential for the discrimination of immature cottons from mature ones and also for the determination of actual cotton maturity. Spectral features of immature and mature cottons revealed large differences in the 1200-900 cm-1 re...

  5. Rapid determination of actinides in seawater samples

    DOE PAGESBeta

    Maxwell, Sherrod L.; Culligan, Brian K.; Hutchison, Jay B.; Utsey, Robin C.; McAlister, Daniel R.

    2014-03-09

    A new rapid method for the determination of actinides in seawater samples has been developed at the Savannah River National Laboratory. The actinides can be measured by alpha spectrometry or inductively-coupled plasma mass spectrometry. The new method employs novel pre-concentration steps to collect the actinide isotopes quickly from 80 L or more of seawater. Actinides are co-precipitated using an iron hydroxide co-precipitation step enhanced with Ti+3 reductant, followed by lanthanum fluoride co-precipitation. Stacked TEVA Resin and TRU Resin cartridges are used to rapidly separate Pu, U, and Np isotopes from seawater samples. TEVA Resin and DGA Resin were used tomore » separate and measure Pu, Am and Cm isotopes in seawater volumes up to 80 L. This robust method is ideal for emergency seawater samples following a radiological incident. It can also be used, however, for the routine analysis of seawater samples for oceanographic studies to enhance efficiency and productivity. In contrast, many current methods to determine actinides in seawater can take 1–2 weeks and provide chemical yields of ~30–60 %. This new sample preparation method can be performed in 4–8 h with tracer yields of ~85–95 %. By employing a rapid, robust sample preparation method with high chemical yields, less seawater is needed to achieve lower or comparable detection limits for actinide isotopes with less time and effort.« less

  6. Rapid determination of actinides in asphalt samples

    SciTech Connect

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

    2014-01-12

    A new rapid method for the determination of actinides in asphalt samples has been developed that can be used in emergency response situations or for routine analysis If a radiological dispersive device (RDD), Improvised Nuclear Device (IND) or a nuclear accident such as the accident at the Fukushima Nuclear Power Plant in March, 2011 occurs, there will be an urgent need for rapid analyses of many different environmental matrices, including asphalt materials, to support dose mitigation and environmental clean up. The new method for the determination of actinides in asphalt utilizes a rapid furnace step to destroy bitumen and organics present in the asphalt and sodium hydroxide fusion to digest the remaining sample. Sample preconcentration steps are used to collect the actinides and a new stacked TRU Resin + DGA Resin column method is employed to separate the actinide isotopes in the asphalt samples. The TRU Resin plus DGA Resin separation approach, which allows sequential separation of plutonium, uranium, americium and curium isotopes in asphalt samples, can be applied to soil samples as well.

  7. Rapid determination of actinides in asphalt samples

    DOE PAGESBeta

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

    2014-01-12

    A new rapid method for the determination of actinides in asphalt samples has been developed that can be used in emergency response situations or for routine analysis If a radiological dispersive device (RDD), Improvised Nuclear Device (IND) or a nuclear accident such as the accident at the Fukushima Nuclear Power Plant in March, 2011 occurs, there will be an urgent need for rapid analyses of many different environmental matrices, including asphalt materials, to support dose mitigation and environmental clean up. The new method for the determination of actinides in asphalt utilizes a rapid furnace step to destroy bitumen and organicsmore » present in the asphalt and sodium hydroxide fusion to digest the remaining sample. Sample preconcentration steps are used to collect the actinides and a new stacked TRU Resin + DGA Resin column method is employed to separate the actinide isotopes in the asphalt samples. The TRU Resin plus DGA Resin separation approach, which allows sequential separation of plutonium, uranium, americium and curium isotopes in asphalt samples, can be applied to soil samples as well.« less

  8. Rapid determination of actinides in seawater samples

    SciTech Connect

    Maxwell, Sherrod L.; Culligan, Brian K.; Hutchison, Jay B.; Utsey, Robin C.; McAlister, Daniel R.

    2014-03-09

    A new rapid method for the determination of actinides in seawater samples has been developed at the Savannah River National Laboratory. The actinides can be measured by alpha spectrometry or inductively-coupled plasma mass spectrometry. The new method employs novel pre-concentration steps to collect the actinide isotopes quickly from 80 L or more of seawater. Actinides are co-precipitated using an iron hydroxide co-precipitation step enhanced with Ti+3 reductant, followed by lanthanum fluoride co-precipitation. Stacked TEVA Resin and TRU Resin cartridges are used to rapidly separate Pu, U, and Np isotopes from seawater samples. TEVA Resin and DGA Resin were used to separate and measure Pu, Am and Cm isotopes in seawater volumes up to 80 L. This robust method is ideal for emergency seawater samples following a radiological incident. It can also be used, however, for the routine analysis of seawater samples for oceanographic studies to enhance efficiency and productivity. In contrast, many current methods to determine actinides in seawater can take 1–2 weeks and provide chemical yields of ~30–60 %. This new sample preparation method can be performed in 4–8 h with tracer yields of ~85–95 %. By employing a rapid, robust sample preparation method with high chemical yields, less seawater is needed to achieve lower or comparable detection limits for actinide isotopes with less time and effort.

  9. Ultra-rapid EOP determination with VLBI

    NASA Astrophysics Data System (ADS)

    Haas, Rüdiger; Kurihara, Shinobu; Nozawa, Kentaro; Hobiger, Thomas; Lovell, Jim; McCallum, Jamie; Quick, Jonathan

    2013-04-01

    In 2007 the Geospatial information Authority of Japan (GSI) and the Onsala Space Observatory (OSO) started a project aiming at determining the earth rotation angle, usually expressed as dUT1, in near real-time. In the beginning of this project dedicated one hour long one-baseline experiments were observed periodically using the VLBI stations Onsala (Sweden) and Tsukuba (Japan). The strategy is that the observed VLBI-data are sent in real-time via the international optical fibre backbone to the VLBI-correlator at Tsukuba where the data are correlated and analyzed in near-real time, producing ultra-rapid dUT1 results. An offline version of this strategy has been adopted in 2009 for the regular VLBI intensive series INT-2 involving Wettzell (Germany) and Tsukuba. Since March 2010 the INT-2 is using real-time e-transfer, too, and since June 2010 also automated analysis. Starting in 2009 the ultra-rapid approach was applied to regular 24 hour long VLBI-sessions that involve Tsukuba and Onsala, so that ultra-rapid dUT1 results can be produced already during ongoing VLBI-sessions. This strategy was successfully operated during the 15 days long CONT11 campaign. In 2011 the ultra-rapid strategy was extended to involve a network of VLBI-stations, so that not only dUT1 but also the polar motion components can be determined in near real-time. Initially, in November 2011 a dedicated three-station session was observed involving Onsala, Tsukuba and Hobart (Tasmania, Australia). In 2012 several regular 24 hour long IVS-sessions that involved Onsala, Tsukuba and HartRAO (South Africa) were operated with the ultra-rapid strategy, and in several cases also Hobart was added as a fourth station. For this project we use the new analysis software c5++ developed by the National Institute of Information and Communications Technology (NICT). In this presentation we give an overview of the UREOP-project, describe the recent developments, and discuss the obtained results.

  10. Novel and rapid method for determination of organophosphorus pesticide residues in edible fungus using direct gas purge microsyringe extraction coupled on-line with gas chromatography-mass spectrometry.

    PubMed

    Nan, Jingxi; Wang, Juan; Piao, Xiangfan; Yang, Cui; Wu, Xue; Quinto, Maurizio; Li, Donghao

    2015-09-01

    In this work a new analytical method for a rapid and simultaneous determination of 28 organophosphorus pesticides (OPPs) residues in edible fungus using gas purge microsyringe extraction (GP-MSE), coupled with on-line gas chromatography-mass spectrometry (GP-MSE-GC-MS) has been developed and optimized. GP-MSE, a novel gas flow liquid-phase microextraction technique, has been then fruitfully used as innovative and one-step extraction procedure, allowing a direct injection into the gas chromatograph coupled with a mass spectrometry detector (GC-MS) system without any further cleaning step. Once optimized, the GP-MSE-GC-MS analysis procedure showed reproducibility values, resolutions, linear responses, detection and quantification limits that allowed to consider this method suitable for the analysis of the 28 OPPs in real samples. Furthermore, OPP recoveries and the relative standard deviations (RSDs) ranged from 85.26% to 100.21%, and from 1.6% to 6.9%, respectively. This procedure was then used for the analysis of real samples and the obtained results were compared with those of ultrasonic extraction-solid phase extraction. Among the 28 OPPs, 14 of them were found in Lentinus edodes and Enoki mushrooms fungus samples, with a total concentrations of 112.7 and 210.7 μg kg(-1), respectively. This work demonstrated then that GP-MSE-GC-MS provided a highly efficient, solvent-saving, accurate and sensitive quantitative analysis method for a rapid determination of OPPs in edible fungus. PMID:26003693

  11. Method for rapidly determining a pulp kappa number using spectrophotometry

    DOEpatents

    Chai, Xin-Sheng; Zhu, Jun Yong

    2002-01-01

    A system and method for rapidly determining the pulp kappa number through direct measurement of the potassium permanganate concentration in a pulp-permanganate solution using spectrophotometry. Specifically, the present invention uses strong acidification to carry out the pulp-permanganate oxidation reaction in the pulp-permanganate solution to prevent the precipitation of manganese dioxide (MnO.sub.2). Consequently, spectral interference from the precipitated MnO.sub.2 is eliminated and the oxidation reaction becomes dominant. The spectral intensity of the oxidation reaction is then analyzed to determine the pulp kappa number.

  12. Rapid authentication of Gastrodiae rhizoma by direct ionization mass spectrometry.

    PubMed

    Wong, Ho-Yi; Hu, Bin; So, Pui-Kin; Chan, Chi-On; Mok, Daniel Kam-Wah; Xin, Gui-Zhong; Li, Ping; Yao, Zhong-Ping

    2016-09-28

    In this study, direct ionization mass spectrometry (DI-MS) for rapid authentication of Gastrodiae rhizoma (known as Tianma in Chinese), a popular herbal medicine, has been developed. This method is rapid, simple and allows direct generation of characteristic mass spectra from the raw herbal medicines with the application of some solvents and a high voltage. The acquired DI-MS spectra showed that gastrodin, parishin B/parishin C and parishin, the major active components of Gastrodiae rhizoma, could be found only in genuine Gastrodiae rhizoma samples, but not in counterfeit samples, thus allowing rapid authentication of Gastrodiae rhizoma. Moreover, wild and cultivated Gastrodiae rhizoma could be classified and Gastrodiae rhizoma from different geographical locations could be differentiated based on their different intensity ratios of characteristic ions or principal component analysis (PCA). This method is simple, rapid, reproducible, and can be extended to analyze other herbal medicines. PMID:27619090

  13. Rapid determination of the energy magnitude Me

    NASA Astrophysics Data System (ADS)

    di Giacomo, D.; Parolai, S.; Bormann, P.; Grosser, H.; Saul, J.; Wang, R.; Zschau, J.

    2009-12-01

    The magnitude of an earthquake is one of the most used parameters to evaluate the earthquake’s damage potential. Among the non-saturating magnitude scales, the energy magnitude Me is related to a well defined physical parameter of the seismic source, that is the radiated seismic energy Es (e.g. Bormann et al., 2002): Me = 2/3(log10 Es - 4.4). Me is more suitable than the moment magnitude Mw in describing an earthquake's shaking potential (Choy and Kirby, 2004). Indeed, Me is calculated over a wide frequency range of the source spectrum and represents a better measure of the shaking potential, whereas Mw is related to the low-frequency asymptote of the source spectrum and is a good measure of the fault size and hence of the static (tectonic) effect of an earthquake. We analyse teleseismic broadband P-waves signals in the distance range 20°-98° to calculate Es. To correct the frequency-dependent energy loss experienced by the P-waves during the propagation path, we use pre-calculated spectral amplitude decay functions for different frequencies obtained from numerical simulations of Green’s functions (Wang, 1999) given the reference Earth model AK135Q (Kennett et al., 1995; Montagner and Kennett, 1996). By means of these functions the correction for the various propagation effects of the recorded P-wave velocity spectra is performed in a rapid and robust way, and the calculation of ES, and hence of Me, can be computed at the single station. We show that our procedure is suitable for implementation in rapid response systems since it could provide stable Me determinations within 10-15 minutes after the earthquake’s origin time, even in case of great earthquakes. We tested our procedure for a large dataset composed by about 770 earthquakes globally distributed in the Mw range 5.5-9.3 recorded at the broadband stations managed by the IRIS, GEOFON, and GEOSCOPE global networks, as well as other regional seismic networks. Me and Mw express two different aspects of

  14. Rapid determination of the energy magnitude Me

    NASA Astrophysics Data System (ADS)

    di Giacomo, D.; Parolai, S.; Bormann, P.; Saul, J.; Grosser, H.; Wang, R.; Zschau, J.

    2009-04-01

    The magnitude of an earthquake is one of the most used parameters to evaluate the earthquake's damage potential. However, many magnitude scales developed over the past years have different meanings. Among the non-saturating magnitude scales, the energy magnitude Me is related to a well defined physical parameter of the seismic source, that is the radiated seismic energy ES (e.g. Bormann et al., 2002): Me = 2/3(log10 ES - 4.4). Me is more suitable than the moment magnitude Mw in describing an earthquake's shaking potential (Choy and Kirby, 2004). Indeed, Me is calculated over a wide frequency range of the source spectrum and represents a better measure of the shaking potential, whereas Mw is related to the low-frequency asymptote of the source spectrum and is a good measure of the fault size and hence of the static (tectonic) effect of an earthquake. The calculation of ES requires the integration over frequency of the squared P-waves velocity spectrum corrected for the energy loss experienced by the seismic waves along the path from the source to the receivers. To accout for the frequency-dependent energy loss, we computed spectral amplitude decay functions for different frequenciesby using synthetic Green's functions (Wang, 1999) based on the reference Earth model AK135Q (Kennett et al., 1995; Montagner and Kennett, 1996). By means of these functions the correction for the various propagation effects of the recorded P-wave velocity spectra is performed in a rapid and robust way, and the calculation of ES, and hence of Me, can be computed at the single station. We analyse teleseismic broadband P-waves signals in the distance range 20°-98°. We show that our procedure is suitable for implementation in rapid response systems since it could provide stable Me determinations within 10-15 minutes after the earthquake's origin time. Indeed, we use time variable cumulative energy windows starting 4 s after the first P-wave arrival in order to include the earthquake rupture

  15. Rapid determination of 226Ra in environmental samples

    SciTech Connect

    Maxwell, Sherrod L.; Culligan, Brian K.

    2012-02-04

    A new rapid method for the determination of {sup 228}Ra in natural water samples has been developed at the SRNL/EBL (Savannah River National Lab/ Environmental Bioassay Laboratory) that can be used for emergency response or routine samples. While gamma spectrometry can be employed with sufficient detection limits to determine {sup 228}Ra in solid samples (via {sup 228}Ac) , radiochemical methods that employ gas flow proportional counting techniques typically provide lower MDA (Minimal Detectable Activity) levels for the determination of {sup 228}Ra in water samples. Most radiochemical methods for {sup 228}Ra collect and purify {sup 228}Ra and allow for {sup 228}Ac daughter ingrowth for ~36 hours. In this new SRNL/EBL approach, {sup 228}Ac is collected and purified from the water sample without waiting to eliminate this delay. The sample preparation requires only about 4 hours so that {sup 228}Ra assay results on water samples can be achieved in < 6 hours. The method uses a rapid calcium carbonate precipitation enhanced with a small amount of phosphate added to enhance chemical yields (typically >90%), followed by rapid cation exchange removal of calcium. Lead, bismuth, uranium, thorium and protactinium isotopes are also removed by the cation exchange separation. {sup 228}Ac is eluted from the cation resin directly onto a DGA Resin cartridge attached to the bottom of the cation column to purify {sup 228}Ac. DGA Resin also removes lead and bismuth isotopes, along with Sr isotopes and {sup 90}Y. La is used to determine {sup 228}Ac chemical yield via ICP-MS, but {sup 133}Ba can also be used instead if ICP-MS assay is not available. Unlike some older methods, no lead or strontium holdback carriers or continual readjustment of sample pH is required.

  16. Rapid-Chill Cryogenic Coaxial Direct-Acting Solenoid Valve

    NASA Technical Reports Server (NTRS)

    Richard, James; Castor, Jim; Sheller, Richard

    2006-01-01

    A commercially available cryogenic direct- acting solenoid valve has been modified to incorporate a rapid-chill feature. The net effect of the modifications is to divert some of the cryogenic liquid to the task of cooling the remainder of the cryogenic liquid that flows to the outlet. Among the modifications are the addition of several holes and a gallery into a valve-seat retainer and the addition of a narrow vent passage from the gallery to the atmosphere.

  17. Rapid analytical determination of glutaraldehyde concentrations

    NASA Technical Reports Server (NTRS)

    Frigerio, N. A.; Shaw, M. H.

    1971-01-01

    Technique utilizes the iodimetric procedure which adds unknown excess of bisulfite to glutaraldehyde /GA/ then titrates unreacted bisulfite with standard iodine isotope to determine GA concentrations. Technique may interest microscopists, food researchers, biochemical or medical laboratories, and drug manufacturers.

  18. Rapid Modeling and Analysis Tools: Evolution, Status, Needs and Directions

    NASA Technical Reports Server (NTRS)

    Knight, Norman F., Jr.; Stone, Thomas J.; Ransom, Jonathan B. (Technical Monitor)

    2002-01-01

    Advanced aerospace systems are becoming increasingly more complex, and customers are demanding lower cost, higher performance, and high reliability. Increased demands are placed on the design engineers to collaborate and integrate design needs and objectives early in the design process to minimize risks that may occur later in the design development stage. High performance systems require better understanding of system sensitivities much earlier in the design process to meet these goals. The knowledge, skills, intuition, and experience of an individual design engineer will need to be extended significantly for the next generation of aerospace system designs. Then a collaborative effort involving the designer, rapid and reliable analysis tools and virtual experts will result in advanced aerospace systems that are safe, reliable, and efficient. This paper discusses the evolution, status, needs and directions for rapid modeling and analysis tools for structural analysis. First, the evolution of computerized design and analysis tools is briefly described. Next, the status of representative design and analysis tools is described along with a brief statement on their functionality. Then technology advancements to achieve rapid modeling and analysis are identified. Finally, potential future directions including possible prototype configurations are proposed.

  19. Pulsatile instability in rapid directional solidification: Strongly-nonlinear analysis

    NASA Technical Reports Server (NTRS)

    Braun, Richard J.; Merchant, G. J.; Brattkus, K.; Davis, S. H.

    1992-01-01

    In models of rapid directional solidification, non-equilibrium interfacial conditions are employed. As a result, there is an oscillatory mode of instability, as well as the steady cellular mode, found in the equilibrium model of Mullins and Sekerka. When the temperature field is decoupled from the problem, the preferred wave number for the oscillatory mode is zero, and the interface pulsates in time while remaining spatially uniform. Results from multiple scale analyses in the two limiting cases of the parameters are reported. In these limits, it is found that the instability is a bifurcation to relaxation oscillations; these nonlinear oscillations may be related to the observed microstructure that results from rapid solidification processes such as laser surface remelting.

  20. Determining Directional Dependency in Causal Associations

    ERIC Educational Resources Information Center

    Pornprasertmanit, Sunthud; Little, Todd D.

    2012-01-01

    Directional dependency is a method to determine the likely causal direction of effect between two variables. This article aims to critique and improve upon the use of directional dependency as a technique to infer causal associations. We comment on several issues raised by von Eye and DeShon (2012), including: encouraging the use of the signs of…

  1. Rapid and Direct Encoding of Numerosity in the Visual Stream.

    PubMed

    Park, Joonkoo; DeWind, Nicholas K; Woldorff, Marty G; Brannon, Elizabeth M

    2016-02-01

    Humans are endowed with an intuitive number sense that allows us to perceive and estimate numerosity without relying on language. It is controversial, however, as to whether there is a neural mechanism for direct perception of numerosity or whether numerosity is perceived indirectly via other perceptual properties. In this study, we used a novel regression-based analytic method, which allowed an assessment of the unique contributions of visual properties, including numerosity, to explain visual evoked potentials of participants passively viewing dot arrays. We found that the human brain is uniquely sensitive to numerosity and more sensitive to changes in numerosity than to changes in other visual properties, starting extremely early in the visual stream: 75 ms over a medial occipital site and 180 ms over bilateral occipitoparietal sites. These findings provide strong evidence for the existence of a neural mechanism for rapidly and directly extracting numerosity information in the human visual pathway. PMID:25715283

  2. Determining wave direction using curvature parameters.

    PubMed

    de Queiroz, Eduardo Vitarelli; de Carvalho, João Luiz Baptista

    2016-01-01

    The curvature of the sea wave was tested as a parameter for estimating wave direction in the search for better results in estimates of wave direction in shallow waters, where waves of different sizes, frequencies and directions intersect and it is difficult to characterize. We used numerical simulations of the sea surface to determine wave direction calculated from the curvature of the waves. Using 1000 numerical simulations, the statistical variability of the wave direction was determined. The results showed good performance by the curvature parameter for estimating wave direction. Accuracy in the estimates was improved by including wave slope parameters in addition to curvature. The results indicate that the curvature is a promising technique to estimate wave directions.•In this study, the accuracy and precision of curvature parameters to measure wave direction are analyzed using a model simulation that generates 1000 wave records with directional resolution.•The model allows the simultaneous simulation of time-series wave properties such as sea surface elevation, slope and curvature and they were used to analyze the variability of estimated directions.•The simultaneous acquisition of slope and curvature parameters can contribute to estimates wave direction, thus increasing accuracy and precision of results. PMID:27408830

  3. Determining Directions of Ultrasound in Solids

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.; Roth, Don J.

    1987-01-01

    Ultrasound shadows cast by grooves. Improved method for determining direction of ultrasound in materials is shadow method using Scanning laser acoustic microscopy (SLAM). Direction of ultrasound calculated from dimensions of groove and portion of surface groove shields from ultrasound. Method has variety of applications in nontraditional quality-control applications.

  4. Rapid exploration of curvilinear grids using direct volume rendering

    NASA Technical Reports Server (NTRS)

    Vangelder, Allen; Wilhelms, Jane

    1993-01-01

    Fast techniques for direct volume rendering over curvilinear grids of hexahedral cells are developed. This type of 3D grid is common in computational fluid dynamics and finite element analysis. Four new projection methods are presented and compared with each other and with previous methods for tetrahedral grids and rectilinear grids. All four methods use polygon-rendering hardware for speed. A simplified algorithm for visibility ordering, which is based on a combination of breadth-first and depth-first searches, is described. A new multi-pass blending method is described that reduces visual artifacts that are introduced by linear interpolation in hardware where exponential interpolation is needed. Multi-pass blending is of equal interest to hardware-oriented projection methods used on rectilinear grids. Visualization tools that permit rapid data banding and cycling through transfer functions, as well as region restrictions, are described.

  5. Flow direction determination of lava flows.

    NASA Technical Reports Server (NTRS)

    Smith, E. I.; Rhodes, R. C.

    1972-01-01

    The flow direction technique, previously applied to ash-flow sheets, can be used to determine direction of movement and locate eruptive centers for lava flows. The method provides statistically stronger and more consistent flow direction data for lava than ash-flow tuff. The accuracy and reliability of the technique was established on the porphyritic basaltic andesite of Mount Taylor, New Mexico, which erupted from a known center, the Mount Taylor Amphitheater. The technique was then applied to volcanic units with unknown sources: the John Kerr Peak Quartz Latite and mid-Tertiary andesite flows in the Mogollon Mountains, both in southwestern New Mexico. The flow direction technique indicated flow patterns and suggested source areas for each rock unit. In the Mogollon Mountains flow direction measurements were supported by independent directional criteria such as dips of cross beds, stratigraphic thickening, facies changes, and megascopic textures.-

  6. Resistive graphene humidity sensors with rapid and direct electrical readout

    NASA Astrophysics Data System (ADS)

    Smith, Anderson D.; Elgammal, Karim; Niklaus, Frank; Delin, Anna; Fischer, Andreas C.; Vaziri, Sam; Forsberg, Fredrik; Råsander, Mikael; Hugosson, Håkan; Bergqvist, Lars; Schröder, Stephan; Kataria, Satender; Östling, Mikael; Lemme, Max C.

    2015-11-01

    We demonstrate humidity sensing using a change of the electrical resistance of single-layer chemical vapor deposited (CVD) graphene that is placed on top of a SiO2 layer on a Si wafer. To investigate the selectivity of the sensor towards the most common constituents in air, its signal response was characterized individually for water vapor (H2O), nitrogen (N2), oxygen (O2), and argon (Ar). In order to assess the humidity sensing effect for a range from 1% relative humidity (RH) to 96% RH, the devices were characterized both in a vacuum chamber and in a humidity chamber at atmospheric pressure. The measured response and recovery times of the graphene humidity sensors are on the order of several hundred milliseconds. Density functional theory simulations are employed to further investigate the sensitivity of the graphene devices towards water vapor. The interaction between the electrostatic dipole moment of the water and the impurity bands in the SiO2 substrate leads to electrostatic doping of the graphene layer. The proposed graphene sensor provides rapid response direct electrical readout and is compatible with back end of the line (BEOL) integration on top of CMOS-based integrated circuits.We demonstrate humidity sensing using a change of the electrical resistance of single-layer chemical vapor deposited (CVD) graphene that is placed on top of a SiO2 layer on a Si wafer. To investigate the selectivity of the sensor towards the most common constituents in air, its signal response was characterized individually for water vapor (H2O), nitrogen (N2), oxygen (O2), and argon (Ar). In order to assess the humidity sensing effect for a range from 1% relative humidity (RH) to 96% RH, the devices were characterized both in a vacuum chamber and in a humidity chamber at atmospheric pressure. The measured response and recovery times of the graphene humidity sensors are on the order of several hundred milliseconds. Density functional theory simulations are employed to further

  7. Cellular instability in rapid directional solidification - Bifurcation theory

    NASA Technical Reports Server (NTRS)

    Braun, R. J.; Davis, S. H.

    1992-01-01

    Merchant and Davis performed a linear stability analysis on a model for the directional solidification of a dilute binary alloy valid for all speeds. The analysis revealed that nonequilibrium segregation effects modify the Mullins and Sekerka cellular mode, whereas attachment kinetics has no effect on these cells. In this paper, the nonlinear stability of the steady cellular mode is analyzed. A Landau equation is obtained that determines the amplitude of the cells. The Landau coefficient here depends on both nonequilibrium segregation effects and attachment kinetics. This equation gives the ranges of parameters for subcritical bifurcation (jump transition) or supercritical bifurcation (smooth transition) to cells.

  8. Pulsatile instability in rapid directional solidification - Strongly-nonlinear analysis

    NASA Technical Reports Server (NTRS)

    Merchant, G. J.; Braun, R. J.; Brattkus, K.; Davis, S. H.

    1992-01-01

    In the rapid directional solidification of a dilute binary alloy, analysis reveals that, in addition to the cellular mode of Mullins and Sekerka (1964), there is an oscillatory instability. For the model analyzed by Merchant and Davis (1990), the preferred wavenumber is zero; the mode is one of pulsation. Two strongly nonlinear analyses are performed that describe this pulsatile mode. In the first case, nonequilibrium effects that alter solute rejection at the interface are taken asymptotically small. A nonlinear oscillator equation governs the position of the solid-liquid interface at leading order, and amplitude and phase evolution equations are derived for the uniformly pulsating interface. The analysis provides a uniform description of both subcritical and supercritical bifurcation and the transition between the two. In the second case, nonequilibrium effects that alter solute rejection are taken asymptotically large, and a different nonlinear oscillator equation governs the location of the interface to leading order. A similar analysis allows for the derivation of an amplitude evolution equation for the uniformly pulsating interface. In this case, the bifurcation is always supercritical. The results are used to make predictions about the characteristics of solute bands that would be frozen into the solid.

  9. RAPID DETERMINATION OF {sup 210} PO IN WATER SAMPLES

    SciTech Connect

    Maxwell, S.

    2013-05-22

    A new rapid method for the determination of {sup 210}Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that can be used for emergency response or routine water analyses. If a radiological dispersive device (RDD) event or a radiological attack associated with drinking water supplies occurs, there will be an urgent need for rapid analyses of water samples, including drinking water, ground water and other water effluents. Current analytical methods for the assay of {sup 210}Po in water samples have typically involved spontaneous auto-deposition of {sup 210}Po onto silver or other metal disks followed by counting by alpha spectrometry. The auto-deposition times range from 90 minutes to 24 hours or more, at times with yields that may be less than desirable. If sample interferences are present, decreased yields and degraded alpha spectrums can occur due to unpredictable thickening in the deposited layer. Separation methods have focused on the use of Sr Resin, often in combination with 210Pb analysis. A new rapid method for {sup 210}Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that utilizes a rapid calcium phosphate co-precipitation method, separation using DGA Resin (N,N,N,N-tetraoctyldiglycolamide extractant-coated resin, Eichrom Technologies or Triskem-International), followed by rapid microprecipitation of {sup 210}Po using bismuth phosphate for counting by alpha spectrometry. This new method can be performed quickly with excellent removal of interferences, high chemical yields and very good alpha peak resolution, eliminating any potential problems with the alpha source preparation for emergency or routine samples. A rapid sequential separation method to separate {sup 210} Po and actinide isotopes was also developed. This new approach, rapid separation with DGA Resin plus microprecipitation for alpha source preparation, is a significant advance in radiochemistry for the rapid

  10. Rapid determination of 226Ra in emergency urine samples

    DOE PAGESBeta

    Maxwell, Sherrod L.; Culligan, Brian K.; Hutchison, Jay B.; Utsey, Robin C.; McAlister, Daniel R.

    2014-02-27

    A new method has been developed at the Savannah River National Laboratory (SRNL) that can be used for the rapid determination of 226Ra in emergency urine samples following a radiological incident. If a radiological dispersive device event or a nuclear accident occurs, there will be an urgent need for rapid analyses of radionuclides in urine samples to ensure the safety of the public. Large numbers of urine samples will have to be analyzed very quickly. This new SRNL method was applied to 100 mL urine aliquots, however this method can be applied to smaller or larger sample aliquots as needed.more » The method was optimized for rapid turnaround times; urine samples may be prepared for counting in <3 h. A rapid calcium phosphate precipitation method was used to pre-concentrate 226Ra from the urine sample matrix, followed by removal of calcium by cation exchange separation. A stacked elution method using DGA Resin was used to purify the 226Ra during the cation exchange elution step. This approach combines the cation resin elution step with the simultaneous purification of 226Ra with DGA Resin, saving time. 133Ba was used instead of 225Ra as tracer to allow immediate counting; however, 225Ra can still be used as an option. The rapid purification of 226Ra to remove interferences using DGA Resin was compared with a slightly longer Ln Resin approach. A final barium sulfate micro-precipitation step was used with isopropanol present to reduce solubility; producing alpha spectrometry sources with peaks typically <40 keV FWHM (full width half max). This new rapid method is fast, has very high tracer yield (>90 %), and removes interferences effectively. The sample preparation method can also be adapted to ICP-MS measurement of 226Ra, with rapid removal of isobaric interferences.« less

  11. Instructional authoring by direct manipulation of simulations: Exploratory applications of RAPIDS. RAPIDS 2 authoring manual

    NASA Technical Reports Server (NTRS)

    1990-01-01

    RAPIDS II is a simulation-based intelligent tutoring system environment. It is a system for producing computer-based training courses that are built on the foundation of graphical simulations. RAPIDS II simulations can be animated and they can have continuously updating elements.

  12. RAPID DETERMINATION OF RA-226 IN ENVIRONMENTAL SAMPLES

    SciTech Connect

    Maxwell, S.

    2012-01-03

    A new rapid method for the determination of {sup 226}Ra in environmental samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for emergency response or routine sample analyses. The need for rapid analyses in the event of a Radiological Dispersive Device or Improvised Nuclear Device event is well-known. In addition, the recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid analyses for radionuclides in environmental samples in the event of a nuclear accident. {sup 226}Ra (T1/2 = 1,620 years) is one of the most toxic of the long-lived alpha-emitters present in the environment due to its long life and its tendency to concentrate in bones, which increases the internal radiation dose of individuals. The new method to determine {sup 226}Ra in environmental samples utilizes a rapid sodium hydroxide fusion method for solid samples, calcium carbonate precipitation to preconcentrate Ra, and rapid column separation steps to remove interferences. The column separation process uses cation exchange resin to remove large amounts of calcium, Sr Resin to remove barium and Ln Resin as a final purification step to remove {sup 225}Ac and potential interferences. The purified {sup 226}Ra sample test sources are prepared using barium sulfate microprecipitation in the presence of isopropanol for counting by alpha spectrometry. The method showed good chemical recoveries and effective removal of interferences. The determination of {sup 226}Ra in environmental samples can be performed in less than 16 h for vegetation, concrete, brick, soil, and air filter samples with excellent quality for emergency or routine analyses. The sample preparation work takes less than 6 h. {sup 225}Ra (T1/2 = 14.9 day) tracer is used and the {sup 225}Ra progeny {sup 217}At is used to determine chemical yield via alpha spectrometry. The rapid fusion technique is a rugged sample digestion method that ensures that any

  13. Rapid Determination Of Radiostrontium In Large Soil Samples

    SciTech Connect

    Maxwell, Sherrod L.; Culligan, Brian K.; Shaw, Patrick J.

    2012-05-24

    A new method for the determination of radiostrontium in large soil samples has been developed at the Savannah River Environmental Laboratory (Aiken, SC, USA) that allows rapid preconcentration and separation of strontium in large soil samples for the measurement of strontium isotopes by gas flow proportional counting. The need for rapid analyses in the event of a Radiological Dispersive Device (RDD) or Improvised Nuclear Device (IND) event is well-known. In addition, the recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid analyses for radionuclides in environmental samples in the event of a nuclear accident. The method employs a novel pre-concentration step that utilizes an iron hydroxide precipitation (enhanced with calcium phosphate) followed by a final calcium fluoride precipitation to remove silicates and other matrix components. The pre-concentration steps, in combination with a rapid Sr Resin separation using vacuum box technology, allow very large soil samples to be analyzed for {sup 89,90}Sr using gas flow proportional counting with a lower method detection limit. The calcium fluoride precipitation eliminates column flow problems typically associated with large amounts of silicates in large soil samples.

  14. Mass Determination Of Directly Imaged Planet Candidates

    NASA Astrophysics Data System (ADS)

    Schmidt, Tobias; Neuhauser, R.; Seifahrt, A.

    2011-09-01

    About 20 sub-stellar companions with large separations (> 50 AU) to their young primary stars and brown dwarfs are confirmed by both common proper motion and late-M / early-L type spectra. The origin and early evolution of these objects is still under debate. While often these sub-stellar companions are regarded as brown dwarfs, they could possibly also be massive planets, the mass estimates are very uncertain so far. They are companions to primary stars or brown dwarfs in young associations and star forming regions like Taurus, Upper Scorpius, the TW Hya association, Beta Pic moving group, TucHor association, Lupus, Ophiuchus, and Chamaeleon, hence their ages and distances are well known, in contrast to free-floating brown dwarfs. Here we present how mass estimates of such young directly imaged companions can be derived, using e.g. evolutionary models, which are however currently almost uncalibrated by direct mass measurements of young objects. An empirical classification by medium-resolution spectroscopy is currently not possible, because a spectral sequence that is taking the lower gravity into account, is not existing. This problem leads to an apparent mismatch between spectra of old field type objects and young low-mass companions at the same effective temperature, hampering a determination of temperature and surface gravity independent from models. We show that from spectra of the objects, using the advantages of light concentration by an AO-assisted integral field spectrograph, temperature, extinction, metallicity and surface gravity can be derived using non-equilibrium radiative transfer atmosphere models as comparison and that this procedure as well allows a mass determination in combination with the luminosities found by the direct observations, as has recently been done by us for several young sub-stellar companions, as e.g. GQ Lup, CT Cha or UScoCTIO 108.

  15. Rapid optical determination of β-lactamase and antibiotic activity

    PubMed Central

    2014-01-01

    Background The absence of rapid tests evaluating antibiotic susceptibility results in the empirical prescription of antibiotics. This can lead to treatment failures due to escalating antibiotic resistance, and also furthers the emergence of drug-resistant bacteria. This study reports a rapid optical method to detect β-lactamase and thereby assess activity of β-lactam antibiotics, which could provide an approach for targeted prescription of antibiotics. The methodology is centred on a fluorescence quenching based probe (β-LEAF – β-Lactamase Enzyme Activated Fluorophore) that mimics the structure of β-lactam antibiotics. Results The β-LEAF assay was performed for rapid determination of β-lactamase production and activity of β-lactam antibiotic (cefazolin) on a panel of Staphylococcus aureus ATCC strains and clinical isolates. Four of the clinical isolates were determined to be lactamase producers, with the capacity to inactivate cefazolin, out of the twenty-five isolates tested. These results were compared against gold standard methods, nitrocefin disk test for β-lactamase detection and disk diffusion for antibiotic susceptibility, showing results to be largely consistent. Furthermore, in the sub-set of β-lactamase producers, it was demonstrated and validated that multiple antibiotics (cefazolin, cefoxitin, cefepime) could be assessed simultaneously to predict the antibiotic that would be most active for a given bacterial isolate. Conclusions The study establishes the rapid β-LEAF assay for β-lactamase detection and prediction of antibiotic activity using S. aureus clinical isolates. Although the focus in the current study is β-lactamase-based resistance, the overall approach represents a broad diagnostic platform. In the long-term, these studies form the basis for the development of assays utilizing a broader variety of targets, pathogens and drugs. PMID:24708478

  16. Micro-apparatus for rapid determinations of protein solubilities

    NASA Technical Reports Server (NTRS)

    Pusey, Marc L.; Munson, Sibyl

    1991-01-01

    We have developed a column-based micro-technique for rapid determinations of protein solubilities. While retaining a large crystal surface area, the column dead volume has been reduced to equal to or less than 5 micro liters. The technique was tested with tetragonal lysozyme (pH 4.5, 0.1 M acetate, 3.0 percent NaCl, 5-25 C) and column volumes of about 60, 300, and 900 micro liters. Identical solubility data were obtained, indicating that equilibration was obtained even in the smallest columns. In addition, solubility data for Br- and I- salts of lysozyme (pH 4.5, 0.1 M acetate buffer, 0.5 M salt concentrations) were obtained. It appears that the technique can be further miniaturized. The limit in further reducing the crystalline column volume is determined by the minimum solution sample size needed to determine the protein concentration.

  17. Simple and rapid determination of myristicin in human serum.

    PubMed

    Dawidowicz, Andrzej L; Dybowski, Michal P

    2013-01-01

    Myristicin (5-allyl-1-methoxy-2,3-methylenodioxybenzene) is the main component of nutmeg (Myristica fragrans Houtt.) essential oil. The increasing use of myristicin as a cheap hallucinogenic intoxicant, frequently causing fatal cases of myristicin poisoning, requires new methods for determination of this compound in blood. This report describes the rapid, simple, and useful procedure for myristicin analysis in human serum, involving myristicin-protein complex degradation before chromatographic analysis. The developed method is characterized by a high recovery (above 99 %), a low detection limit (6.0 ng/g) and good repeatability (average RDS of 2.01 %). PMID:23440626

  18. Rapid determination of global moment-tensor solutions

    USGS Publications Warehouse

    Sipkin, S.A.

    1994-01-01

    In an effort to improve data services, the National Earthquake Information Center has begun a program, in cooperation with the Incorporated Research Institutions for Seismology Data Management Center (IRIS DMC), to produce rapid estimates of the seismic moment tensor for most earthquakes with a bodywave magnitude of 5.8 or greater. An estimate of the moment tensor can usually be produced within 20 minutes of the arrival of the broadband P-waveform data from the IRIS DMC. The solutions do not vary significantly from the final solutions determined using the entire network. -from Author

  19. Directed Random Markets: Connectivity Determines Money

    NASA Astrophysics Data System (ADS)

    Martínez-Martínez, Ismael; López-Ruiz, Ricardo

    2013-12-01

    Boltzmann-Gibbs (BG) distribution arises as the statistical equilibrium probability distribution of money among the agents of a closed economic system where random and undirected exchanges are allowed. When considering a model with uniform savings in the exchanges, the final distribution is close to the gamma family. In this paper, we implement these exchange rules on networks and we find that these stationary probability distributions are robust and they are not affected by the topology of the underlying network. We introduce a new family of interactions: random but directed ones. In this case, it is found the topology to be determinant and the mean money per economic agent is related to the degree of the node representing the agent in the network. The relation between the mean money per economic agent and its degree is shown to be linear.

  20. Determining the direction of a turbulent cascade

    NASA Astrophysics Data System (ADS)

    Goldburg, Walter; Cerbus, Rory

    2015-11-01

    In two-dimensional (2D) turbulence, one expects a cascade of energy to larger spatial scales, while the enstrophy cascade is to smaller ones. Here we present a new tool to study cascades using simple ideas borrowed from information theory. It is entirely unrelated to the Navier-Stoke's equations or any scaling arguments. We use the conditional entropy (conditioned uncertainty) of velocity fluctuations on one scale conditioned on another larger or smaller scale. If the entropy is larger after conditioning on larger scales rather than smaller ones, then the cascade is to smaller scales. By varying the scale of the velocity fluctuations used in the conditioning, we can test both direction and locality. We use these tools on experimental data taken from a flowing soap film, an approximately 2D turbulent flow. The Reynolds number is varied over a wide range to determine the entropy's scaling with Reynolds number OIST.

  1. Rapid determination of particle size distribution of microbead catalysts

    SciTech Connect

    Mirshii, Y.V.; Goos, T.V.; Kaviev, V.M.; Kazahov, G.I.; Klimov, A.V.; Nesmeyanova, T.S.

    1986-05-01

    The authors have developed a rapid method for the determination of the particle size distribution of microbead catalysts by a photosedimentation method. This method is based on a determination of the settling velocity of the particles according to the change in optical density of the suspension as the particles settle. The design of the instrument was modified for application to the analysis of microbead cracking catalysts and microbead zeolites; it was originally developed for studies of particle size distribution in other materials. The measuring part of the AFS-2M photosedimentograph is shown schematically. For the high-zeolite catalysts, the results obtained by photosedimenation analysis are somewhat different from those obtained by the pipette method. The photosedimentation method can also be used in the analysis of microbead zeolites that are intended for use in the fluid-bed recovery of liquid paraffins.

  2. Rapid infrared determination of the potency of chlorinated bactericides.

    PubMed

    Spagnolo, F; Cestaro, J P

    1971-06-01

    A rapid infrared reflectance method for evaluating the germicidal potency of synthetic materials containing various amounts of two chlorinated bactericides was developed. The dimeric product 2,2'-methylenebis (4,6-dichlorophenol) exhibited a characteristic C=C skeletal inplane stretching infrared absorption band at 1,640 cm(-1). The monomeric 2,4-dichlorophenol precursor showed a characteristic absorption band at 1,579 cm(-1). These characteristic infrared absorptions may be used for analysis of the potency of the manufactured chlorinated bactericide. For a series of samples known to vary in dimer content, the micrograms per milliliter required for a 100% bacterial kill is first determined by a standard American Petroleum Institute method. Then the area ratio of the infrared absorption bands characteristic of the chlorinated bactericides is measured for each sample and plotted versus the microgram per milliliter required for 100% bacterial kill. The potency of subsequent samples is simply and rapidly determined by measuring this ratio from the infrared absorption curve and calculating micrograms per milliliter required for 100% kill from the calibration curve. Analysis time is approximately 1 hr compared to biocidal tests in current use requiring approximately a 1-month incubation period. PMID:5564677

  3. Rapid determination of nanogram amounts of tellurium in silicate rocks

    USGS Publications Warehouse

    Greenland, L.P.; Campbell, E.Y.

    1976-01-01

    A hydride-generation flameless atomic-absorption technique is used to determine as little as 5 ng g-1 tellurium in 0.25 g of silicate rock. After acid decomposition of the sample, tellurium hydride is generated with sodium borohydride and the vapor passed directly to a resistance-heated quartz cell mounted in an atomic-absorption spectrophotometer. Analyses of 11 U.S. Geological Survey standard rocks are presented. ?? 1976.

  4. Evaluation of a Rapid Bauer-Kirby Antibiotic Susceptibility Determination

    PubMed Central

    Liberman, Daniel F.; Robertson, Richard G.

    1975-01-01

    To reduce the incubation time requirement in the Bauer-Kirby antibiotic susceptibility test, comparisons were made of the test results at 18 to 20 h (standard) and 7 to 8 h (rapid) utilizing 100 recent clinical isolates. The zone diameters for 664 disks were monitored by using the standard classification: resistant, intermediate, or susceptible. The susceptibility determination was unchanged in 558 out of 664 instances (84.0%). An analysis of the remaining 106 sets revealed that an initial interpretation of intermediate in zone size, subsequently determined resistant or susceptible, accounted for 49 of the observed differences. The reverse changes, initial resistant or susceptible subsequently classified as intermediate, accounted for 20 of the changes. In five instances the interpretation changed from susceptible to resistant; in two cases the interpretation changed from resistant to susceptible. The remaining 30 determinations were classified as indeterminant due to (i) insufficient growth at the early (7 to 8 h) determination, and to (ii) zones which were so large that they could not be measured accurately. The data indicate that zone sizes when measured to the nearest 0.1 mm can be interpreted with reasonable accuracy and the results can be available 10 to 14 h sooner. PMID:1137377

  5. Motion Planning for a Direct Metal Deposition Rapid Prototyping System

    SciTech Connect

    AMES,ARLO L.; HENSINGER,DAVID M.; KUHLMANN,JOEL L.

    1999-10-18

    A motion planning strategy was developed and implemented to generate motion control instructions from solid model data for controlling a robotically driven solid free-form fabrication process. The planning strategy was tested using a PUMA type robot arm integrated into a LENS{trademark} (Laser Engineered Net Shape) system. Previous systems relied on a series of x, y, and z stages, to provide a minimal coordinated motion control capability. This limited the complexity of geometries that could be constructed. With the coordinated motion provided by a robotic arm, the system can produce three dimensional parts by ''writing'' material onto any face of existing material. The motion planning strategy relied on solid model geometry evaluation and exploited robotic positioning flexibility to allow the construction of geometrically complex parts. The integration of the robotic manipulator into the LENS{trademark} system was tested by producing metal parts directly from CAD models.

  6. Interferometric Laser Scanner for Direction Determination.

    PubMed

    Kaloshin, Gennady; Lukin, Igor

    2016-01-01

    In this paper, we explore the potential capabilities of new laser scanning-based method for direction determination. The method for fully coherent beams is extended to the case when interference pattern is produced in the turbulent atmosphere by two partially coherent sources. The performed theoretical analysis identified the conditions under which stable pattern may form on extended paths of 0.5-10 km in length. We describe a method for selecting laser scanner parameters, ensuring the necessary operability range in the atmosphere for any possible turbulence characteristics. The method is based on analysis of the mean intensity of interference pattern, formed by two partially coherent sources of optical radiation. Visibility of interference pattern is estimated as a function of propagation pathlength, structure parameter of atmospheric turbulence, and spacing of radiation sources, producing the interference pattern. It is shown that, when atmospheric turbulences are moderately strong, the contrast of interference pattern of laser scanner may ensure its applicability at ranges up to 10 km. PMID:26805841

  7. Interferometric Laser Scanner for Direction Determination

    PubMed Central

    Kaloshin, Gennady; Lukin, Igor

    2016-01-01

    In this paper, we explore the potential capabilities of new laser scanning-based method for direction determination. The method for fully coherent beams is extended to the case when interference pattern is produced in the turbulent atmosphere by two partially coherent sources. The performed theoretical analysis identified the conditions under which stable pattern may form on extended paths of 0.5–10 km in length. We describe a method for selecting laser scanner parameters, ensuring the necessary operability range in the atmosphere for any possible turbulence characteristics. The method is based on analysis of the mean intensity of interference pattern, formed by two partially coherent sources of optical radiation. Visibility of interference pattern is estimated as a function of propagation pathlength, structure parameter of atmospheric turbulence, and spacing of radiation sources, producing the interference pattern. It is shown that, when atmospheric turbulences are moderately strong, the contrast of interference pattern of laser scanner may ensure its applicability at ranges up to 10 km. PMID:26805841

  8. Determining orientation and direction of DNA sequences

    DOEpatents

    Goodwin, Edwin H.; Meyne, Julianne

    2000-01-01

    Determining orientation and direction of DNA sequences. A method by which fluorescence in situ hybridization can be made strand specific is described. Cell cultures are grown in a medium containing a halogenated nucleotide. The analog is partially incorporated in one DNA strand of each chromatid. This substitution takes place in opposite strands of the two sister chromatids. After staining with the fluorescent DNA-binding dye Hoechst 33258, cells are exposed to long-wavelength ultraviolet light which results in numerous strand nicks. These nicks enable the substituted strand to be denatured and solubilized by heat, treatment with high or low pH aqueous solutions, or by immersing the strands in 2.times.SSC (0.3M NaCl+0.03M sodium citrate), to name three procedures. It is unnecessary to enzymatically digest the strands using Exo III or another exonuclease in order to excise and solubilize nucleotides starting at the sites of the nicks. The denaturing/solubilizing process removes most of the substituted strand while leaving the prereplication strand largely intact. Hybridization of a single-stranded probe of a tandem repeat arranged in a head-to-tail orientation will result in hybridization only to the chromatid with the complementary strand present.

  9. Rapid Enzymatic Method for Pectin Methyl Esters Determination

    PubMed Central

    Łękawska-Andrinopoulou, Lucyna; Vasiliou, Efstathios G.; Georgakopoulos, Dimitrios G.; Yialouris, Constantinos P.; Georgiou, Constantinos A.

    2013-01-01

    Pectin is a natural polysaccharide used in food and pharma industries. Pectin degree of methylation is an important parameter having significant influence on pectin applications. A rapid, fully automated, kinetic flow method for determination of pectin methyl esters has been developed. The method is based on a lab-made analyzer using the reverse flow-injection/stopped flow principle. Methanol is released from pectin by pectin methylesterase in the first mixing coil. Enzyme working solution is injected further downstream and it is mixed with pectin/pectin methylesterase stream in the second mixing coil. Methanol is oxidized by alcohol oxidase releasing formaldehyde and hydrogen peroxide. This reaction is coupled to horse radish peroxidase catalyzed reaction, which gives the colored product 4-N-(p-benzoquinoneimine)-antipyrine. Reaction rate is proportional to methanol concentration and it is followed using Ocean Optics USB 2000+ spectrophotometer. The analyzer is fully regulated by a lab written LabVIEW program. The detection limit was 1.47 mM with an analysis rate of 7 samples h−1. A paired t-test with results from manual method showed that the automated method results are equivalent to the manual method at the 95% confidence interval. The developed method is rapid and sustainable and it is the first application of flow analysis in pectin analysis. PMID:24455426

  10. Rapid determination of plasmonic nanoparticle agglomeration status in blood.

    PubMed

    Jenkins, Samir V; Qu, Haiou; Mudalige, Thilak; Ingle, Taylor M; Wang, Rongrong; Wang, Feng; Howard, Paul C; Chen, Jingyi; Zhang, Yongbin

    2015-05-01

    Plasmonic nanomaterials as drug delivery or bio-imaging agents are typically introduced to biological systems through intravenous administration. However, the potential for agglomeration of nanoparticles in biological systems could dramatically affect their pharmacokinetic profile and toxic potential. Development of rapid screening methods to evaluate agglomeration is urgently needed to monitor the physical nature of nanoparticles as they are introduced into blood. Here, we establish novel methods using darkfield microscopy with hyperspectral detection (hsDFM), single particle inductively-coupled plasma mass spectrometry (spICP-MS), and confocal Raman microscopy (cRM) to discriminate gold nanoparticles (AuNPs) and their agglomerates in blood. Rich information about nanoparticle agglomeration in situ is provided by hsDFM monitoring of the plasmon resonance of primary nanoparticles and their agglomerates in whole blood; cRM is an effective complement to hsDFM to detect AuNP agglomerates in minimally manipulated samples. The AuNPs and the particle agglomerates were further distinguished in blood for the first time by quantification of particle mass using spICP-MS with excellent sensitivity and specificity. Furthermore, the agglomeration status of synthesized and commercial NPs incubated in blood was successfully assessed using the developed methods. Together, these complementary methods enable rapid determination of the agglomeration status of plasmonic nanomaterials in biological systems, specifically blood. PMID:25771013

  11. Rapid Determination of Plasmonic Nanoparticle Agglomeration Status in Blood

    PubMed Central

    Jenkins, Samir V.; Qu, Haiou; Mudalige, Thilak; Ingle, Taylor; Wang, RongRong; Wang, Feng; Howard, Paul C.; Chen, Jingyi; Zhang, Yongbin

    2015-01-01

    Plasmonic nanomaterials as drug delivery or bio-imaging agents are typically introduced to biological systems through intravenous administration. However, the potential for agglomeration of nanoparticles in biological systems could dramatically affect their pharmacokinetic profile and toxic potential. Development of rapid screening methods to evaluate agglomeration is urgently needed to monitor the physical nature of nanoparticles as they are introduced into blood. Here, we establish novel methods using darkfield microscopy with hyperspectral detection (hsDFM), single particle inductively-coupled plasma mass spectrometry (spICP-MS), and confocal Raman microscopy (cRM) to discriminate gold nanoparticles (AuNPs) and their agglomerates in blood. Rich information about nanoparticle agglomeration in situ is provided by hsDFM monitoring of the plasmon resonance of primary nanoparticles and their agglomerates in whole blood; cRM is an effective complement to hsDFM to detect AuNP agglomerates in minimally manipulated samples. The AuNPs and the particle agglomerates were further distinguished in blood for the first time by quantification of particle mass using spICP-MS with excellent sensitivity and specificity. Furthermore, the agglomeration status of synthesized and commercial NPs incubated in blood was successfully assessed using the developed methods. Together, these complementary methods enable rapid determination of the agglomeration status of plasmonic nanomaterials in biological systems, specifically blood. PMID:25771013

  12. Rapid enzymatic method for pectin methyl esters determination.

    PubMed

    Lękawska-Andrinopoulou, Lucyna; Vasiliou, Efstathios G; Georgakopoulos, Dimitrios G; Yialouris, Constantinos P; Georgiou, Constantinos A

    2013-01-01

    Pectin is a natural polysaccharide used in food and pharma industries. Pectin degree of methylation is an important parameter having significant influence on pectin applications. A rapid, fully automated, kinetic flow method for determination of pectin methyl esters has been developed. The method is based on a lab-made analyzer using the reverse flow-injection/stopped flow principle. Methanol is released from pectin by pectin methylesterase in the first mixing coil. Enzyme working solution is injected further downstream and it is mixed with pectin/pectin methylesterase stream in the second mixing coil. Methanol is oxidized by alcohol oxidase releasing formaldehyde and hydrogen peroxide. This reaction is coupled to horse radish peroxidase catalyzed reaction, which gives the colored product 4-N-(p-benzoquinoneimine)-antipyrine. Reaction rate is proportional to methanol concentration and it is followed using Ocean Optics USB 2000+ spectrophotometer. The analyzer is fully regulated by a lab written LabVIEW program. The detection limit was 1.47 mM with an analysis rate of 7 samples h(-1). A paired t-test with results from manual method showed that the automated method results are equivalent to the manual method at the 95% confidence interval. The developed method is rapid and sustainable and it is the first application of flow analysis in pectin analysis. PMID:24455426

  13. Rapid direct methods for enumeration of specific, active bacteria in water and biofilms

    NASA Technical Reports Server (NTRS)

    McFeters, G. A.; Pyle, B. H.; Lisle, J. T.; Broadaway, S. C.

    1999-01-01

    Conventional methods for detecting indicator and pathogenic bacteria in water may underestimate the actual population due to sublethal environmental injury, inability of the target bacteria to take up nutrients and other physiological factors which reduce bacterial culturability. Rapid and direct methods are needed to more accurately detect and enumerate active bacteria. Such a methodological advance would provide greater sensitivity in assessing the microbiological safety of water and food. The principle goal of this presentation is to describe novel approaches we have formulated for the rapid and simultaneous detection of bacteria plus the determination of their physiological activity in water and other environmental samples. The present version of our method involves the concentration of organisms by membrane filtration or immunomagnetic separation and combines an intracellular fluorochrome (CTC) for assessment of respiratory activity plus fluorescent-labelled antibody detection of specific bacteria. This approach has also been successfully used to demonstrate spatial and temporal heterogeneities of physiological activities in biofilms when coupled with cryosectioning. Candidate physiological stains include those capable of determining respiratory activity, membrane potential, membrane integrity, growth rate and cellular enzymatic activities. Results obtained thus far indicate that immunomagnetic separation can provide a high degree of sensitivity in the recovery of seeded target bacteria (Escherichia coli O157:H7) in water and hamburger. The captured and stained target bacteria are then enumerated by either conventional fluorescence microscopy or ChemScan(R), a new instrument that is very sensitive and rapid. The ChemScan(R) laser scanning instrument (Chemunex, Paris, France) provides the detection of individual fluorescently labelled bacterial cells using three emission channels in less than 5 min. A high degree of correlation has been demonstrated between

  14. Rapid Determination of the Presence of Enteric Bacteria in Water

    PubMed Central

    Kenard, R. P.; Valentine, R. S.

    1974-01-01

    A rapid and sensitive method is described for the detection of bacteria in water and various other natural substrates by the isolation of specific bacteriophage. By the addition of large numbers of the organism in question to the sample, the presence of virulent bacteriophage can be demonstrated in as little as 6 to 8 h. Fecal coliform, total coliform, and total coliphage counts were determined for over 150 water samples from several geographical areas over a period of 2 years. Computer analysis of the data shows a high degree of correlation between fecal coliforms and the coliphage present in the samples. With a high correlation coefficient between fecal coliform and coliphage counts, predictions of the fecal coliforms may be made by enumeration of the phage. PMID:4596384

  15. Evaluation of a rapid method of determination of plasma fibrinogen.

    PubMed

    Thomson, G W; McSherry, B J; Valli, V E

    1974-07-01

    An evaluation was made of a rapid semiautomated method of determining fibrinogen levels in bovine plasma. This method, the fibrometer method of Morse, Panek and Menga (8), is based on the principle that when thrombin is added to suitably diluted plasma the time of clotting is linearly related to the fibrinogen concentration. A standard curve prepared using bovine plasma had an r value of .9987 and analysis of variance showed there was no significant deviation from regression. A comparison of the fibrometer method and the biuret method of Ware, Guest and Seegers done on 158 bovine plasma samples showed good correlation between the two methods. It was concluded that the fibrometer method does measure bovine fibrinogen and has considerable merit for use in clinical diseases of cattle. PMID:4277474

  16. A rapid quantitative determination of acetaminophen in plasma.

    PubMed

    O'Connell, S E; Zurzola, F J

    1982-11-01

    A simple method is described for the rapid, quantitative analysis of acetaminophen in plasma. The nonconjugated acetaminophen present in the plasma following drug administration is determined after plasma protein precipitation by high-pressure liquid chromatography (HPLC) at a wavelength of 240 nm. Acetaminophen (I) is detectable at levels as low as 0.1 microgram/ml. Mean recoveries of 94% with a coefficient of variation of 3% were obtained for plasma standards whose concentrations ranged from 0 to 32 microgram/ml. Interassay variability of the slope of the standard curve had a coefficient of variation of 2.7%. Application and verification of this method by comparison with another procedure run simultaneously during several human bioavailability studies are described. PMID:7175728

  17. [Rapid Determination of Seven Fungicides in Citrus Fruits].

    PubMed

    Yoshioka, Naoki; Hayashi, Sachiko; Inada, Tadaaki

    2015-01-01

    A rapid and simple determination method of seven fungicides, thiabendazole (TBZ), pyrimethanil (PYR), o-phenylphenol (OPP), fludioxonil (FLD), azoxystrobin (AZX), imazalil (IMZ) and diphenyl (DP) in citrus fruits by LC-MS and HPLC-FL was developed. The seven fungicides were extracted with acetonitrile from citrus fruits and cleaned up with Z-Sep/C18 cartridges. The LC separation was performed on a phenyl-hexyl column with methanol-acetonitrile-10 mmol/L ammonium formate (10 : 35 : 55) as a mobile phase. The recoveries from citrus fruits fortified with the compounds at the MRLs and at 0.1 μg/g ranged from 85.4 to 106.3% and from 75.8 to 99.7%, respectively. The quantitation limits (S/N=10) were 0.03-0.07 μg/g. PMID:26537653

  18. Integrated microfluidic immunoassay for the rapid determination of clenbuterol.

    PubMed

    Kong, Jing; Jiang, Lei; Su, Xiaoou; Qin, Jianhua; Du, Yuguang; Lin, Bingcheng

    2009-06-01

    An integrated microfluidic immunoassay system was established for high throughput analysis of clenbuterol. This system consisted of an integrated microchip and a linear confocal laser induced fluorescence (LIF) scanner. The microchip was composed of three layers: a fluidic channel layer, a PDMS membrane layer and a pneumatic control layer. The multi-layer chip was integrated with 36 pneumatic micro-valves and multiple micro-pumps to realize the flexible reagent delivery, facilitating the automatic assays with less consumption of samples and reduced analysis time. The homemade LIF scanner was able to simultaneously detect multi-channels and provide the potential capability of high throughput assays. The performance of the system was demonstrated by the determination of clenbuterol, one of the most widely used beta-agonists. Under the optimal conditions, the linear range and the limit of detection of clenbuterol were 0 approximately 5.0 ng mL(-1) and 0.088 ng mL(-1), respectively. The recovery rates determined with pig urine samples of 1.0 ng mL(-1) and 2.0 ng mL(-1) were 98.74% and 102.51% (n = 3), respectively. The total detection time was less than 30 min. The system had the potential application for rapid detection of multiple beta-agonists in clinical, pharmaceutical and chemical analyses. PMID:19458860

  19. Direct spectrophotometric determination of alkylphenol polyethoxylate nonionic surfactants in wastewater.

    PubMed

    Zhu, Zhenzhong; Li, Zaijun; Hao, Zhuoli; Chen, Jian

    2003-11-01

    A new spectrophotometric method is proposed for direct determination of alkylphenol polyethoxylate, RO(CH(2)CH(2)O)(n)H (where R is alkylphenyl and n is the degree of polymerization), in wastewater. The method is based on the formation of ternary complex, Pb(II)-meso-tetra-(3,5-dibromo-4-hydrooxyphenyl)-Porphyrin (T(DBHP)P)-alkylphenol polyethoxylate (APE). Under optimum reaction conditions, T(DBHP)P reacts with lead(II) and APE to form a yellow ternary complex with the maximum absorption peak at 479 nm. The color reaction is rapidly completed and the absorbance remains stable for at least 24h under room temperature. The apparent molar absorption coefficients were 0.4-4.3 x 10(4) L mol(-1) cm(-1) for n=5-50. As little as 0.02 microg mL(-1) of APE can be detected. The effects of various substances on the determination of APE were also investigated in detail. It was found that all the studied co-existing substances, especially cationic and anionic surfactants, which always seriously interfere in some reported methods, could be tolerated in considerable amounts. The method offered the advantages of simplicity, rapidity, sensitivity and selectivity without any prior separation or extraction. PMID:14511721

  20. Rapid determination of alpha emitters using Actinide resin.

    PubMed

    Navarro, N; Rodriguez, L; Alvarez, A; Sancho, C

    2004-01-01

    The European Commission has recently published the recommended radiological protection criteria for the clearance of building and building rubble from the dismantling of nuclear installations. Radionuclide specific clearance levels for actinides are very low (between 0.1 and 1 Bq g(-1)). The prevalence of natural radionuclides in rubble materials makes the verification of these levels by direct alpha counting impossible. The capability of Actinide resin (Eichrom Industries, Inc.) for extracting plutonium and americium from rubble samples has been tested in this work. Besides a strong affinity for actinides in the tri, tetra and hexavalent oxidation states, this extraction chromatographic resin presents an easy recovery of absorbed radionuclides. The retention capability was evaluated on rubble samples spiked with certified radionuclide standards (239Pu and 241Am). Samples were leached with nitric acid, passed through a chromatographic column containing the resin and the elution fraction was measured by LSC. Actinide retention varies from 60% to 80%. Based on these results, a rapid method for the verification of clearance levels for actinides in rubble samples is proposed. PMID:15177360

  1. Rapid Determination of the Thermal Nociceptive Threshold in Diabetic Rats

    PubMed Central

    Alshahrani, Saeed; Fernandez-Conti, Filipe; Araujo, Amanda; DiFulvio, Mauricio

    2012-01-01

    Painful diabetic neuropathy (PDN) is characterized by hyperalgesia i.e., increased sensitivity to noxious stimulus, and allodynia i.e., hypersensitivity to normally innocuous stimuli1. Hyperalgesia and allodynia have been studied in many different rodent models of diabetes mellitus2. However, as stated by Bölcskei et al, determination of "pain" in animal models is challenging due to its subjective nature3. Moreover, the traditional methods used to determine behavioral responses to noxious thermal stimuli usually lack reproducibility and pharmacological sensitivity3. For instance, by using the hot-plate method of Ankier4, flinch, withdrawal and/or licking of either hind- and/or fore-paws is quantified as reflex latencies at constant high thermal stimuli (52-55 °C). However, animals that are hyperalgesic to thermal stimulus do not reproducibly show differences in reflex latencies using those supra-threshold temperatures3,5. As the recently described method of Bölcskei et al.6, the procedures described here allows for the rapid, sensitive and reproducible determination of thermal nociceptive thresholds (TNTs) in mice and rats. The method uses slowly increasing thermal stimulus applied mostly to the skin of mouse/rat plantar surface. The method is particularly sensitive to study anti-nociception during hyperalgesic states such as PDN. The procedures described bellow are based on the ones published in detail by Almási et al5 and Bölcskei et al3. The procedures described here have been approved the Laboratory Animal Care and Use Committee (LACUC), Wright State University. PMID:22643870

  2. Procedure for rapid determination of nickel, cobalt, and chromium in airborne particulate samples

    NASA Technical Reports Server (NTRS)

    Davis, W. F.; Graab, J. W.

    1972-01-01

    A rapid, selective procedure for the determination of 1 to 20 micrograms of nickel, chromium, and cobalt in airborne particulates is described. The method utilizes the combined techniques of low temperature ashing and atomic absorption spectroscopy. The airborne particulates are collected on analytical filter paper. The filter papers are ashed, and the residues are dissolved in hydrochloric acid. Nickel, chromium, and cobalt are determined directly with good precision and accuracy by means of atomic absorption. The effects of flame type, burner height, slit width, and lamp current on the atomic absorption measurements are reported.

  3. Rapid analysis of Callicarpa L. using direct spray ionization mass spectrometry.

    PubMed

    Liu, Jingjing; Gu, Zhixin; Yao, Shouzuo; Zhang, Zhaohui; Chen, Bo

    2016-05-30

    Direct spray such as leaf spray and paper spray ionization mass spectrometry (MS) is a powerful type of ambient MS for phytochemical analysis. In this paper, direct spray MS methods to rapidly distinguish and analyze five species of Callicarpa L. have been developed. To distinguish species, leaf spray MS was employed to directly analyze leaves. A small triangular leaf sample was wetted with 15μL of spray solvent and a high DC voltage was then simply applied to the wet leaf sample, which was positioned in front of the inlet of a mass spectrometer to produce electrospray ionization. The MS signals of phenylpropanoid glycosides, i.e. forsythiaside B, poliumoside, verbascoside in leaves could be sensitively detected. The content characteristics of the phenylpropanoid glycosides in five species including Callicarpae kwangtungensis Folium, Callicarpae macrophyllae Folium, Callicarpa nudiflora Folium, Callicarpae formosanae Folium, Callicarpa longissima Folium could be used to distinguish them, then the mass spectra of the Callicarpa L. samples were analyzed using principal component analysis(PCA) or partial least squares-discriminant analysis(PLS-DA). For the rapid semi-quantitative analysis, of phenylpropanoid glycosides in leaves, paper spray MS was employed to determine phenylpropanoid glycosides in the extracts of Callicarpa L. leaves. Ginsenoside Rg1 was selected as an internal standard (I.S.). The calibration curves were constructed through ratios of target ion abundance to I.S. ion abundance vs. concentration of targets. The linearity range was 8-250μg/mL (R(2)=0.9947) for forsythiaside B, 9-280μg/mL (R(2)=0.9939) for verbascoside, and 9-260μg/mL (R(2)=0.9917) for poliumoside, respectively. The limit of detection (LOD) was 1μg/mL, 0.5μg/mL and 1μg/mL for forsythiaside B, verbascoside, and poliumoside, respectively. PMID:26938160

  4. Modeling of rapid direct-contact condensation. Report on phase 1 (Final)

    SciTech Connect

    Wallis, G.B.; Richter, H.J.; Valenzuela, J.A.; Rothe, P.H.

    1985-08-01

    The focus of the study is on rapid direct-contact condensation phenomena, that is, direct-contact condensation situations characterized by extremely high condensation rates and violent mixing at the liquid-vapor interface. Rapid condensation phenomena arise in many industrial processes, but general methods do not presently exist to design effective components or to avoid system-flow instability. A conceptual model and preliminary analysis of rapid condensation are presented, and preliminary, proof-of-concept experiments are described. Some background information and a brief survey of previous work in the area are also provided.

  5. Rapid Direct Action of Estradiol in GnRH Neurons: Findings and Implications

    PubMed Central

    Kenealy, Brian P.; Terasawa, E.

    2011-01-01

    Estradiol plays a pivotal role in the control of gonadotropin-releasing hormone (GnRH) neuronal function and female reproduction. While positive and negative feedback actions of estradiol that enhance and suppress release of GnRH and LH are primarily mediated through estrogen receptor alpha located in interneurons, a series of recent studies in our laboratory indicate that rapid excitatory actions of estradiol also directly modify GnRH neuronal activity. We observed this phenomenon in cultured primate GnRH neurons, but similar rapid direct actions of estradiol are also described in cultured GnRH neurons and green fluorescent protein-labeled GnRH neurons of mice. Importantly, rapid direct action of estradiol in GnRH neurons is mediated through membrane or membrane associated receptors, such as GPR30, STX-sensitive receptors, and ERβ. In this review, possible implications of this rapid estradiol action in GnRH neurons are discussed. PMID:22654841

  6. Determination of rapid chlorination rate constants by a stopped-flow spectrophotometric competition kinetics method.

    PubMed

    Song, Dean; Liu, Huijuan; Qiang, Zhimin; Qu, Jiuhui

    2014-05-15

    Free chlorine is extensively used for water and wastewater disinfection nowadays. However, it still remains a big challenge to determine the rate constants of rapid chlorination reactions although competition kinetics and stopped-flow spectrophotometric (SFS) methods have been employed individually to investigate fast reaction kinetics. In this work, we proposed an SFS competition kinetics method to determine the rapid chlorination rate constants by using a common colorimetric reagent, N,N-diethyl-p-phenylenediamine (DPD), as a reference probe. A kinetic equation was first derived to estimate the reaction rate constant of DPD towards chlorine under a given pH and temperature condition. Then, on that basis, an SFS competition kinetics method was proposed to determine directly the chlorination rate constants of several representative compounds including tetracycline, ammonia, and four α-amino acids. Although Cl2O is more reactive than HOCl, its contribution to the overall chlorination kinetics of the test compounds could be neglected in this study. Finally, the developed method was validated through comparing the experimentally measured chlorination rate constants of the selected compounds with those obtained or calculated from literature and analyzing with Taft's correlation as well. This study demonstrates that the SFS competition kinetics method can measure the chlorination rate constants of a test compound rapidly and accurately. PMID:24602867

  7. Determination of saponins in legumes by direct densitometry.

    PubMed

    Gurfinkel, D M; Rao, A V

    2002-01-30

    Research has shown that dietary saponins may have health benefits. A simple, rapid method for the determination of saponins in legumes, using densitometry, is described. Saponin preparations, after pretreatment to remove nonsaponin components, are spotted in rows on a thin-layer chromatography plate, along with soyasaponin standards. The plate, without solvent development, is directly treated with sulfuric acid and heated. Violet spots develop which have a density proportional to the amount of saponin present. The standard curve has a correlation coefficient of 0.99 and is linear over the range of 1.25 to 10 microg of soyasaponins applied. The method has a coefficient of variation of less than 3% and compares favorably with quantitative thin-layer chromatography. Using this method the saponin contents of defatted soy flour (0.58%), dried navy beans (0.32%), and dried kidney beans (0.29%) were determined, and these results were found to be consistent with previous reports in the literature. PMID:11804507

  8. 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.

  9. Rapid distortion analysis and direct simulation of compressible homogeneous turbulence at finite Mach number

    NASA Technical Reports Server (NTRS)

    Cambon, C.; Coleman, G. N.; Mansour, N. N.

    1992-01-01

    The effect of rapid mean compression on compressible turbulence at a range of turbulent Mach numbers is investigated. Rapid distortion theory (RDT) and direct numerical simulation results for the case of axial (one-dimensional) compression are used to illustrate the existence of two distinct rapid compression regimes. These regimes are set by the relationships between the timescales of the mean distortion, the turbulence, and the speed of sound. A general RDT formulation is developed and is proposed as a means of improving turbulence models for compressible flows.

  10. Determination of direct alcohol markers: a review.

    PubMed

    Cabarcos, Pamela; Álvarez, Iván; Tabernero, María Jesús; Bermejo, Ana María

    2015-07-01

    Alcohol is the most popular legal drug used in our society today, and its consumption by pregnant women remains an important public health problem. Gestational alcohol consumption can result in a continuum of adverse fetal outcomes known as fetal alcohol spectrum disorder (FASD). Effective strategies are needed to prevent the increasing adoption of risky drinking behaviors. Because ethanol itself is only measurable for a few hours after ethanol intake in conventional matrices including blood, urine, and sweat, these matrices are only useful to detect recent ethanol exposure. Since approximately early 2000, the non-oxidative ethanol metabolites have received increasing attention because of their specificity and, in some cases, wide time window of detection in non-conventional matrices including hair and meconium. In the attempt to update analytical methods for the determination of non-oxidative markers of alcohol, the objective of this study is to review published studies that measure fatty-acid ethyl esters (FAEE), ethyl glucuronide (EtG), and phosphatidylethanol (PEth) in alternative biological matrices, focusing on the extraction and detection methods and full analytical conditions used. PMID:25935676

  11. Direct Determination of Nonmetals in Solution with Atomic Spectrometry.

    ERIC Educational Resources Information Center

    McGregor, David A.; And Others

    1988-01-01

    Addresses solution nonmetal determinations on a fundamental level. Characterizes research in this area of chemical instrumentation. Discusses the fundamental limitations of nonmetal atomic spectrometry, the status of nonmetals and atomic spectroscopic techniques, and current directions in solution nonmetal determinations. (CW)

  12. Direct, Specific and Rapid Detection of Staphylococcal Proteins and Exotoxins Using a Multiplex Antibody Microarray

    PubMed Central

    Stieber, Bettina; Monecke, Stefan; Müller, Elke; Büchler, Joseph; Ehricht, Ralf

    2015-01-01

    Background S. aureus is a pathogen in humans and animals that harbors a wide variety of virulence factors and resistance genes. This bacterium can cause a wide range of mild to life-threatening diseases. In the latter case, fast diagnostic procedures are important. In routine diagnostic laboratories, several genotypic and phenotypic methods are available to identify S. aureus strains and determine their resistances. However, there is a demand for multiplex routine diagnostic tests to directly detect staphylococcal toxins and proteins. Methods In this study, an antibody microarray based assay was established and validated for the rapid detection of staphylococcal markers and exotoxins. The following targets were included: staphylococcal protein A, penicillin binding protein 2a, alpha- and beta-hemolysins, Panton Valentine leukocidin, toxic shock syndrome toxin, enterotoxins A and B as well as staphylokinase. All were detected simultaneously within a single experiment, starting from a clonal culture on standard media. The detection of bound proteins was performed using a new fluorescence reading device for microarrays. Results 110 reference strains and clinical isolates were analyzed using this assay, with a DNA microarray for genotypic characterization performed in parallel. The results showed a general high concordance of genotypic and phenotypic data. However, genotypic analysis found the hla gene present in all S. aureus isolates but its expression under given conditions depended on the clonal complex affiliation of the actual isolate. Conclusions The multiplex antibody assay described herein allowed a rapid and reliable detection of clinically relevant staphylococcal toxins as well as resistance- and species-specific markers. PMID:26624622

  13. Note: Non-invasive optical method for rapid determination of alignment degree of oriented nanofibrous layers.

    PubMed

    Pokorny, M; Klemes, J; Rebicek, J; Kotzianova, A; Velebny, V

    2015-10-01

    This paper presents a rapid non-destructive method that provides information on the anisotropic internal structure of nanofibrous layers. A laser beam of a wavelength of 632.8 nm is directed at and passes through a nanofibrous layer prepared by electrostatic spinning. Information about the structural arrangement of nanofibers in the layer is directly visible in the form of a diffraction image formed on a projection screen or obtained from measured intensities of the laser beam passing through the sample which are determined by the dependency of the angle of the main direction of polarization of the laser beam on the axis of alignment of nanofibers in the sample. Both optical methods were verified on Polyvinyl alcohol (PVA) nanofibrous layers (fiber diameter of 470 nm) with random, single-axis aligned and crossed structures. The obtained results match the results of commonly used methods which apply the analysis of electron microscope images. The presented simple method not only allows samples to be analysed much more rapidly and without damaging them but it also makes possible the analysis of much larger areas, up to several square millimetres, at the same time. PMID:26521008

  14. Note: Non-invasive optical method for rapid determination of alignment degree of oriented nanofibrous layers

    NASA Astrophysics Data System (ADS)

    Pokorny, M.; Klemes, J.; Rebicek, J.; Kotzianova, A.; Velebny, V.

    2015-10-01

    This paper presents a rapid non-destructive method that provides information on the anisotropic internal structure of nanofibrous layers. A laser beam of a wavelength of 632.8 nm is directed at and passes through a nanofibrous layer prepared by electrostatic spinning. Information about the structural arrangement of nanofibers in the layer is directly visible in the form of a diffraction image formed on a projection screen or obtained from measured intensities of the laser beam passing through the sample which are determined by the dependency of the angle of the main direction of polarization of the laser beam on the axis of alignment of nanofibers in the sample. Both optical methods were verified on Polyvinyl alcohol (PVA) nanofibrous layers (fiber diameter of 470 nm) with random, single-axis aligned and crossed structures. The obtained results match the results of commonly used methods which apply the analysis of electron microscope images. The presented simple method not only allows samples to be analysed much more rapidly and without damaging them but it also makes possible the analysis of much larger areas, up to several square millimetres, at the same time.

  15. Note: Non-invasive optical method for rapid determination of alignment degree of oriented nanofibrous layers

    SciTech Connect

    Pokorny, M.; Rebicek, J.; Klemes, J.; Kotzianova, A.; Velebny, V.

    2015-10-15

    This paper presents a rapid non-destructive method that provides information on the anisotropic internal structure of nanofibrous layers. A laser beam of a wavelength of 632.8 nm is directed at and passes through a nanofibrous layer prepared by electrostatic spinning. Information about the structural arrangement of nanofibers in the layer is directly visible in the form of a diffraction image formed on a projection screen or obtained from measured intensities of the laser beam passing through the sample which are determined by the dependency of the angle of the main direction of polarization of the laser beam on the axis of alignment of nanofibers in the sample. Both optical methods were verified on Polyvinyl alcohol (PVA) nanofibrous layers (fiber diameter of 470 nm) with random, single-axis aligned and crossed structures. The obtained results match the results of commonly used methods which apply the analysis of electron microscope images. The presented simple method not only allows samples to be analysed much more rapidly and without damaging them but it also makes possible the analysis of much larger areas, up to several square millimetres, at the same time.

  16. Estimation and modeling of direct rapid sand filtration for total fecal coliform removal from secondary clarifier effluents.

    PubMed

    Li, Yi; Yu, Jingjing; Liu, Zhigang; Ma, Tian

    2012-01-01

    The filtration of fecal coliform from a secondary clarifier effluent was investigated using direct rapid sand filters as tertiary wastewater treatment on a pilot scale. The effect of the flocculation dose, flow loading rate, and grain size on fecal coliform removal was determined. Direct rapid sand filters can remove 0.6-1.5 log-units of fecal coliform, depending on the loading rate and grain size distribution. Meanwhile, the flocculation dose has little effect on coliform removal, and increasing the loading rate and/or grain size decreases the bacteria removal efficiency. A model was then developed for the removal process. Bacteria elimination and inactivation both in the water phase and the sand bed can be described by first-order kinetics. Removal was successfully simulated at different loading rates and grain size distributions and compared with the data obtained using pilot-scale filters. PMID:22508124

  17. Direct Detection of Nocardia spp. in Clinical Samples by a Rapid Molecular Method

    PubMed Central

    Couble, Andrée; Rodríguez-Nava, Verónica; de Montclos, Michèle Pérouse; Boiron, Patrick; Laurent, Frédéric

    2005-01-01

    We developed a 16S PCR-based assay for the rapid detection of Nocardia spp. directly from human clinical samples. The applicability of the assay was confirmed by using 18 samples from patients with nocardiosis as diagnosed by conventional cultures and 20 clinical samples from patients with confirmed tuberculosis used as negative controls. PMID:15815019

  18. Rapid prototyping of frequency selective surfaces by laser direct-write

    NASA Astrophysics Data System (ADS)

    Mathews, Scott A.; Mirotznik, Mark; Good, Brandon L.; Piqué, Alberto

    2007-02-01

    In this work we describe the use of laser direct-write for the rapid prototyping of frequency selective surfaces. Frequency selective surfaces are generally described by a periodic array of conducting or dielectric features (i.e. crosses, loops, grids, etc.) that when properly designed can pass or reject specific frequency bands of incoming electromagnetic radiation. While simple frequency selective surfaces are relatively straight forward to design and fabricate, operational demands, particularly military, have motivated the design and fabrication of much more complicated patterns. These new designs combine features of significantly different length scales, randomly dithered patterns and combinations of passive and active elements. We will demonstrate how laser direct-write is an ideal tool for the rapid prototyping of these new more complicated frequency selective surface designs. We will present experimental results for devices fabricated using several different laser direct-write processes.

  19. Rapid computation of directional wellbore drawdown in a confined aquifer via Poisson resummation

    NASA Astrophysics Data System (ADS)

    Blumenthal, Benjamin J.; Zhan, Hongbin

    2016-08-01

    We have derived a rapidly computed analytical solution for drawdown caused by a partially or fully penetrating directional wellbore (vertical, horizontal, or slant) via Green's function method. The mathematical model assumes an anisotropic, homogeneous, confined, box-shaped aquifer. Any dimension of the box can have one of six possible boundary conditions: 1) both sides no-flux; 2) one side no-flux - one side constant-head; 3) both sides constant-head; 4) one side no-flux; 5) one side constant-head; 6) free boundary conditions. The solution has been optimized for rapid computation via Poisson Resummation, derivation of convergence rates, and numerical optimization of integration techniques. Upon application of the Poisson Resummation method, we were able to derive two sets of solutions with inverse convergence rates, namely an early-time rapidly convergent series (solution-A) and a late-time rapidly convergent series (solution-B). From this work we were able to link Green's function method (solution-B) back to image well theory (solution-A). We then derived an equation defining when the convergence rate between solution-A and solution-B is the same, which we termed the switch time. Utilizing the more rapidly convergent solution at the appropriate time, we obtained rapid convergence at all times. We have also shown that one may simplify each of the three infinite series for the three-dimensional solution to 11 terms and still maintain a maximum relative error of less than 10-14.

  20. New Algorithm for CAD Solid Model Direct Slicing on Rapid Prototyping

    NASA Astrophysics Data System (ADS)

    Zhou, Huiqun; Wu, Jianjun

    In the paper, a new algorithm for CAD solid model direct slicing has been given. The three-dimensional CAD solid models have been divided into a series of layer which meeting tolerance required on the basis of rapid prototyping. Section contour extraction method has been adopted, then, section contour has been into line, arc, free curves, and the data is stored in a specific file format. In the contour interior, scanning area has been formed. The examples show that the algorithm can better achieve layered manufacturing to rapid prototyping.

  1. Rapidly patterning micro/nano devices by directly assembling ions and nanomaterials

    PubMed Central

    Liu, Na; Wang, Feifei; Liu, Lianqing; Yu, Haibo; Xie, Shaorong; Wang, Jun; Wang, Yuechao; Lee, Gwo-Bin; Li, Wen J.

    2016-01-01

    The synthesis and assembly of components are key steps in micro/nano device manufacturing. In this article, we report an optically controlled assembly method that can rapidly pattern micro/nano devices by directly assembling ions and nanomaterials without expensive physical masks and complex etching processes. Utilizing this controllable process, different types of device components (e.g., metallic and semiconductor) can be fabricated and assembled in 10–30 seconds, which is far more rapid and cost-effective than any other micro/nano fabrication method. PMID:27561917

  2. Rapidly patterning micro/nano devices by directly assembling ions and nanomaterials.

    PubMed

    Liu, Na; Wang, Feifei; Liu, Lianqing; Yu, Haibo; Xie, Shaorong; Wang, Jun; Wang, Yuechao; Lee, Gwo-Bin; Li, Wen J

    2016-01-01

    The synthesis and assembly of components are key steps in micro/nano device manufacturing. In this article, we report an optically controlled assembly method that can rapidly pattern micro/nano devices by directly assembling ions and nanomaterials without expensive physical masks and complex etching processes. Utilizing this controllable process, different types of device components (e.g., metallic and semiconductor) can be fabricated and assembled in 10-30 seconds, which is far more rapid and cost-effective than any other micro/nano fabrication method. PMID:27561917

  3. Rapid determination of filterable residue in natural waters

    USGS Publications Warehouse

    Allen, Herbert E.; Bacon, Charles W.

    1969-01-01

    The most widely used procedures for determining filterable residue (total dissolved solids) in water are macromethods given in Standard Methods. Although macromethods give good results, they require large amounts of water and long drying times. This report describes a microtechnique for determining filterable residue that requires only 0.05 ml of water and 15 min/sample drying time. The sensitivity of the method is within the range (4 mg/l or 5 per cent) given in Standard Methods and that reported by Sokoloff.

  4. Evaluating an alternative method for rapid urinary creatinine determination

    EPA Science Inventory

    Creatinine (CR) is an endogenously-produced chemical routinely assayed in urine specimens to assess kidney function, sample dilution. The industry-standard method for CR determination, known as the kinetic Jaffe (KJ) method, relies on an exponential rate of a colorimetric change,...

  5. A rapid method for the determination of lithium transference numbers

    SciTech Connect

    Zawodzinski, T.A. Jr.; Dai, H.; Sanderson, S.; Davey, J.; Uribe, F.

    1997-05-01

    Lithium ion-conducting polymer electrolytes are of increasing interest for use in lithium-polymer batteries. Lithium transference numbers, the net fraction of current carried by lithium in a cell, are key figures of merit for potential lithium battery electrolytes. The authors describe the Electrophoretic NMR (ENMR) method for the determination of lithium ion transference numbers (T{sub Li}). The work presented is a proof-of-concept of the application of the ENMR method to lithium ion transference measurements for several different lithium salts in gelled electrolytes. The NMR method allows accurate determination of T{sub Li} values, as indicated by the similarity of T{sub Li} in the gelled electrolytes to those in aqueous electrolyte solutions at low salt concentration. Based on calculated tradeoffs of various experimental parameters, they also discuss some conclusions concerning the range of applicability of the method to other electrolytes with lower lithium mobility.

  6. A portable photoelectrochemical probe for rapid determination of chemical oxygen demand in wastewaters.

    PubMed

    Zhang, Shanqing; Li, Lihong; Zhao, Huijun

    2009-10-15

    A photoelectrochemical probe for rapid determination of chemical oxygen demand (COD) is developed using a nanostructured mixed-phase TiO2 photoanode, namely PeCOD probe. A UV-LED light source and a USB mircroelectrochemical station are powered and controlled by a laptop computer, which makes the probe portable for onsite COD analyses. The photoelectrochemical measurement of COD was optimized in terms of light intensity, applied bias, and pH. Under the optimized conditions, the net steady state currents originated from the oxidation of organic compounds were found to be directly proportional to COD concentrations. A practical detection limit of 0.2 ppm COD and a linear range of 0-120 ppm COD were achieved. The analytical method using the portable PeCOD probe has the advantages of being rapid, low cost, robust, user-friendly, and environmental friendly. It has been successfully applied to determine the COD values of the synthetic samples consisting of potassium hydrogen phthalate, D-glucose, glutamic acid, glutaric acid, succinic acid, and malonic acid, and real samples from various industries, such as bakery, oil and grease manufacturer, poultry, hotel, fine food factory, and fresh food producer, commercial bread manufacturer. Excellent agreement between the proposed method and the conventional COD method (dichromate) was achieved. PMID:19921898

  7. Rapid determination of 5-hydroxymethylfurfural by DART ionization with time-of-flight mass spectrometry.

    PubMed

    Rajchl, Aleš; Drgová, Ladislava; Grégrová, Adéla; Cížková, Helena; Sevčík, Rudolf; Voldřich, Michal

    2013-05-01

    DART (direct analysis in real time), a novel technique with wide potential for rapid screening analysis, coupled with high-resolution time-of-flight mass spectrometry (TOF-MS) has been used for quantitative analysis of 5-hydroxymethylfurfural (5-HMF), a typical temperature marker of food. The DART/TOF-MS method was optimised and validated. Quantification of 5-HMF was achieved by use of a stable isotope-labelled 5-HMF standard prepared from glucose. Formation of 5-HMF from saccharides, a potential source of overestimation of results, was evaluated. Forty-four real samples (honey and caramelised condensed sweetened milk) and 50 model samples of heated honey were analysed. The possibility of using DART for analysis of heated samples of honey was confirmed. HPLC and DART/TOF-MS methods for determination of 5-HMF were compared. The correlation equation between these methods was DART = 1.0287HPLC + 0.21340, R(2) = 0.9557. The DART/TOF-MS method has been proved to enable efficient and rapid determination of 5-HMF in a variety of food matrices, for example honey and caramel. PMID:23503749

  8. A rapid geochemical spectrophotometric determination of tungsten with dithiol

    USGS Publications Warehouse

    Welsch, E.P.

    1983-01-01

    1-g sample is decomposed with nitric and hydrofluoric acids, and after evaporation of the solution to dryness the residue is dissolved in concentrated hydrochloric acid. A clear aliquot is treated with stannous chloride to inhibit interferences. The blue tungsten dithiol complex is developed at a temperature of 85?? over a half-hour period. The complex is extracted into 2 ml of heptane and the tungsten is determined spectrophotometrically with a sensitivity of 0.5 ppm. Fifty samples per man-day can be analysed in this manner. ?? 1983.

  9. Novel rapidity dependence of directed flow in high-energy heavy-Ion collisions

    PubMed

    Snellings; Sorge; Voloshin; Wang; Xu

    2000-03-27

    For high-energy nucleus-nucleus collisions, we show that a combination of space-momentum correlations characteristic of radial expansion, together with the correlation between the position of a nucleon in the nucleus and its stopping, results in a very specific rapidity dependence of directed flow: a reversal of sign in the midrapidity region. We support our argument by RQMD model calculations for Au+Au collisions at sqrt[s] = 200A GeV. PMID:11018946

  10. Measurements of Direct Photon Double Longitudinal Spin Asymmetry at Large Rapidity

    NASA Astrophysics Data System (ADS)

    Bourgeois, Paul

    2008-10-01

    Direct photon production in polarized p-p collisions is expected to be the cleanest measurement of the gluon polarization. Current measurements using inclusive pion production, in the PHENIX central arms, suggest a small contribution from the gluons to the proton spin in the presently accessible Bjorken x range xBj>10-2. The addition of the Nose Cone Calorimeter (NCC) in the large rapidity 1<η<3 will allow PHENIX to access xBj˜10-3. In this talk I will present the prospects of measuring direct photon double longitudinal spin asymmetry ALL employing the NCC.

  11. Rapid and Sensitive Voltammetric Determination of Aclonifen in Water Samples.

    PubMed

    Guziejewski, Dariusz; Smarzewska, Sylwia; Skowron, Monika; Ciesielski, Witold; Nosal-Wiercinłska, Agnieszka; Skrzypek, Slawomira

    2016-01-01

    This paper presents the use of square wave voltammetry (SWV) and square wave adsorptive stripping voltammetry (SWAdSV) in conjunction with a cyclic renewable silver amalgam film electrode (Hg(Ag)FE) for the determination of aclonifen in spiked water samples. A reduction peak at -0.65 V versus Ag/AgCl was obtained in the selected buffer (borax buffer with pH 9.2), exhibiting the characteristics of an irreversible reaction. The effect of square wave (SW) frequency, SW amplitude and step potential, as well as accumulation parameters (time and potential) were studied to select the optimal experimental conditions. The calibration curve was linear in the aclonifen concentration range from 1.0×10(-7) to 1.0×10(-6) mol L(-1) and from 1.0×10(-8) to1.0×10(-7) mol L(-1) for SWV and SWAdSV, respectively. The detection and quantification limits were found to be 3.1×10(-8) mol L(-1); 1.0×10(-7) mol L(-1) and 2.9×10(-9) mol L(-1); 9.6×10(-9) mol L-1 for SWV and SWAdSV, respectively. The proposed method was applied successfully in the determination of aclonifen in spiked water samples. The developed procedure can be adequate at least for screening purposes, where positive results should be confirmed by more selective method. PMID:26970782

  12. Separation-free electrochemical immunosensor for rapid determination of atrazine.

    PubMed

    Keay, R W; McNeil, C J

    1998-10-15

    A separation-free electrochemical immunoassay method for the detection of the pesticide atrazine is described. The method developed is a competitive ELISA incorporating disposable screen printed horseradish peroxidase modified electrodes as the detector element in conjunction with single-use atrazine immuno-membranes. Screen printed carbon electrodes were prepared using carbon ink incorporating horseradish peroxidase. A monoclonal antibody for atrazine was immobilised onto Biodyne C membranes which were, in turn, placed over the electrode surface. The assay was based on competition for available binding sites between free atrazine and an atrazine-glucose oxidase conjugate prepared 'in-house'. In the presence of glucose, H2O2 formed by the conjugate was reduced by enzyme-channelling via the HRP electrode. The HRP was in turn re-reduced by a direct electron transfer mechanism at a potential of +50 mV Vs Ag/AgCl. Any H2O2 formed in the bulk solution by unbound atrazine-GOD conjugate was scavenged by excess catalase thus removing the requirement for a washing step. The performance of the method was compared with a commercial immunoassay kit for atrazine. PMID:9839385

  13. Rapid determination of RMSDs corresponding to macromolecular rigid body motions.

    PubMed

    Popov, Petr; Grudinin, Sergei

    2014-05-01

    Finding the root mean sum of squared deviations (RMSDs) between two coordinate vectors that correspond to the rigid body motion of a macromolecule is an important problem in structural bioinformatics, computational chemistry, and molecular modeling. Standard algorithms compute the RMSD with time proportional to the number of atoms in the molecule. Here, we present RigidRMSD, a new algorithm that determines a set of RMSDs corresponding to a set of rigid body motions of a macromolecule in constant time with respect to the number of atoms in the molecule. Our algorithm is particularly useful for rigid body modeling applications, such as rigid body docking, and also for high-throughput analysis of rigid body modeling and simulation results. We also introduce a constant-time rotation RMSD as a similarity measure for rigid molecules. A C++ implementation of our algorithm is available at http://nano-d.inrialpes.fr/software/RigidRMSD. PMID:24615729

  14. [Simple and rapid screening for psychotropic natural products using Direct Analysis in Real Time (DART)-TOFMS].

    PubMed

    Kawamura, Maiko; Kikura-Hanajiri, Ruri; Goda, Yukihiro

    2009-06-01

    Direct Analysis in Real Time (DART) is a novel ionization technique that provides for the rapid ionization of small molecules under ambient conditions. To investigate the trend of non-controlled psychotropic plants of abuse in Japan, a rapid screening method, without sample preparation, was developed using DART-time of flight mass spectrometer (TOFMS) for plant products. The major psychotropic constituents of these products were determined using liquid chromatography-mass spectrometry (LC/MS). As a result of the DART-TOFMS analyses of 36 products, the protonated molecular ions [M+H](+), corresponding to 6 kinds of major hallucinogenic constituents (mescaline, salvinorin A, N,N-dimethyltryptamine, harmine, harmaline and lysergamide), were detected in 21 products. It was possible to estimate their accurate elemental compositions through exact mass measurements. These results were consistent with those of the LC/MS analyses and the contents of the 6 psychotropic constituents were in the range from 0.05 to 45 microg/mg. Typical controlled narcotic drugs, tetrahydrocannabinol, opioid alkaloids and psilocin were also directly detected in marijuana cigarette, opium gum and magic mushroom respectively. Although it is difficult to estimate the matrix effects caused by other plant ingredients, the DART-TOFMS could be useful as a simple and rapid screening method for the targeted psychotropic natural products, because it provides the molecular information of the target compounds without time-consuming extraction and pre-treatment steps. PMID:19483414

  15. Rapid Staphylococcus aureus agr type determination by a novel multiplex real-time quantitative PCR assay.

    PubMed

    Francois, Patrice; Koessler, Thibaud; Huyghe, Antoine; Harbarth, Stephan; Bento, Manuela; Lew, Daniel; Etienne, Jérôme; Pittet, Didier; Schrenzel, Jacques

    2006-05-01

    The accessory gene regulator (agr) is a crucial regulatory component of Staphylococcus aureus involved in the control of bacterial virulence factor expression. We developed a real-time multiplex quantitative PCR assay for the rapid determination of S. aureus agr type. This assay represents a rapid and affordable alternative to sequence-based strategies for assessing relevant epidemiological information. PMID:16672433

  16. Rapid Staphylococcus aureus agr Type Determination by a Novel Multiplex Real-Time Quantitative PCR Assay

    PubMed Central

    Francois, Patrice; Koessler, Thibaud; Huyghe, Antoine; Harbarth, Stephan; Bento, Manuela; Lew, Daniel; Etienne, Jérôme; Pittet, Didier; Schrenzel, Jacques

    2006-01-01

    The accessory gene regulator (agr) is a crucial regulatory component of Staphylococcus aureus involved in the control of bacterial virulence factor expression. We developed a real-time multiplex quantitative PCR assay for the rapid determination of S. aureus agr type. This assay represents a rapid and affordable alternative to sequence-based strategies for assessing relevant epidemiological information. PMID:16672433

  17. DEVELOPMENT OF A RAPID ANALYTICAL METHOD FOR DETERMINING ASBESTOS IN WATER

    EPA Science Inventory

    The development of a rapid analytical method for determining chrysotile asbestos in water that requires substantially less time per analysis than electron microscopy methods is described. Based on the proposition that separation of chrysotile from other waterborne particulate wou...

  18. Rapid Determination of Mercury in Seafood in an Introductory Environmental Science Class

    ERIC Educational Resources Information Center

    Rice, Jeanette K.; Jenkins, J. David; Manley, A. Citabria; Sorel, Eric; Smith, C. Jimmy

    2005-01-01

    An experiment is described which allows easy, rapid determination of mercury levels in commercially seafood samples from a contaminated area. Students gain experience in the preparation of a calibration curve, the determination of unknown concentrations, and risk assessment based on experimentally determined data.

  19. A general geometric theory of attitude determination from directional sensing

    NASA Technical Reports Server (NTRS)

    Fang, B. T.

    1976-01-01

    A general geometric theory of spacecraft attitude determination from external reference direction sensors was presented. Outputs of different sensors are reduced to two kinds of basic directional measurements. Errors in these measurement equations are studied in detail. The partial derivatives of measurements with respect to the spacecraft orbit, the spacecraft attitude, and the error parameters form the basis for all orbit and attitude determination schemes and error analysis programs and are presented in a series of tables. The question of attitude observability is studied with the introduction of a graphical construction which provides a great deal of physical insight. The result is applied to the attitude observability of the IMP-8 spacecraft.

  20. A study on the diamond lapping direction determination

    NASA Astrophysics Data System (ADS)

    Yang, Ning; Zong, WenJun; Li, ZengQiang; Sun, Tao

    2014-08-01

    The anisotropy of material removal rate for diamond gives a method to control the lapping rate of diamond specimen, i.e. changing the lapping direction. This requires comprehension on the relationship of the material removal rate and the lapping direction for diamond. This paper provides a method to figure out the diamond lapping direction. By preprocessing a straight edge formed by lapping a surface intersects with the required machining surface, the diamond lapping direction can be figured out under the Confocal Scanning Laser Microscope only if the crystal directions of the two surfaces are determined at first. The advantage of our method is that there is no need to consider the position and posture of the diamond specimen fixed on the holder.

  1. Method for determining shear direction using liquid crystal coatings

    NASA Technical Reports Server (NTRS)

    Reda, Daniel C.

    1995-01-01

    A method is provided for determining shear direction wherein a beam of white light is directed onto the surface of a liquid crystal coating to cause the white light to be dispersed (reflected) from the surface in a spectrum having bands of different colors in a fixed spatial 2 (angular) sequence. The system is calibrated by locating an observer, e.g., a video and movie camera, such that a particular color band (preferably at or near the center of the reflected spectrum) is observed to thereby provide a reference color band. Because the application of shear causes either clockwise or counterclockwise rotation of the reflected spectrum dependent on the direction of the shear, a determination is then made of the reflected color band observed by the observer when the surface of the liquid crystal is subjected to shear to thereby determine the direction of the shear based on the directional (rotation) relation of the observed color band with respect to the reference color band in the spatial sequence of color bands.

  2. Direct experimental determination of Frisch grid inefficiency in ionization chamber

    NASA Astrophysics Data System (ADS)

    Khriachkov, V. A.; Goverdovski, A. A.; Ketlerov, V. V.; Mitrofanov, V. F.; Semenova, N. N.

    1997-07-01

    The present work describes the method of direct experimental determination of the Frisch grid inefficiency in an ionization chamber. The method is based on analysis of the anode signal after Waveform Digitizer. It is shown that the calculated grid inefficiency value can differ much from the measured ones.

  3. Direct potentiometric determination of diastase activity in honey.

    PubMed

    Sak-Bosnar, Milan; Sakač, Nikola

    2012-11-15

    A novel method for the determination of diastase activity is reported. The method is based on a direct potentiometric measurement of triiodide ion that is released when a starch-triiodide complex is hydrolysed by honey diastase. The increase of free triiodide ion concentration in a sample is found to be directly proportional to the diastase activity of the sample. A response mechanism of the platinum redox electrode is proposed, allowing a calculation of the diastase activity factor (F). The sensor and analyte parameters, including F, were obtained by least squares fitting of potentiometric data using the optimisation function of the Solver add-in of Microsoft Excel. The values of F obtained by the new direct potentiometric method were compared with those obtained using the standard Phadebas method (DN values), and the two values were found to agree within experimental error. Finally, the diastase activity of nine varieties of honey was determined using the novel method developed here. PMID:22868165

  4. Direct determination of the hit locations from experimental HPGe pulses

    NASA Astrophysics Data System (ADS)

    Désesquelles, P.; Boston, A. J.; Boston, H. C.; Cresswell, J. R.; Dimmock, M. R.; Lazarus, I. H.; Ljungvall, J.; Nelson, L.; Nga, D.-T.; Nolan, P. J.; Rigby, S. V.; Simpson, J.; Van-Oanh, N.-T.

    2013-11-01

    The gamma-tracking technique optimises the determination of the energy and emission angle of gamma-rays detected by modern segmented HPGe detectors. This entails the determination, using the delivered pulse shapes, of the interaction points of the gamma-ray within the crystal. The direct method presented here allows the localisation of the hits using only a large sample of pulses detected in the actual operating conditions. No external crystal scanning system or pulse shape simulation code is needed. In order to validate this method, it is applied to sets of pulses obtained using the University of Liverpool scanning system. The hit locations are determined by the method with good precision.

  5. Rapid Directional Change Degrades GPS Distance Measurement Validity during Intermittent Intensity Running

    PubMed Central

    Rawstorn, Jonathan C.; Maddison, Ralph; Ali, Ajmol; Foskett, Andrew; Gant, Nicholas

    2014-01-01

    Use of the Global Positioning System (GPS) for quantifying athletic performance is common in many team sports. The effect of running velocity on measurement validity is well established, but the influence of rapid directional change is not well understood in team sport applications. This effect was systematically evaluated using multidirectional and curvilinear adaptations of a validated soccer simulation protocol that maintained identical velocity profiles. Team sport athletes completed 90 min trials of the Loughborough Intermittent Shuttle-running Test movement pattern on curvilinear, and multidirectional shuttle running tracks while wearing a 5 Hz (with interpolated 15 Hz output) GPS device. Reference total distance (13 200 m) was systematically over- and underestimated during curvilinear (2.61±0.80%) and shuttle (−3.17±2.46%) trials, respectively. Within-epoch measurement uncertainty dispersion was widest during the shuttle trial, particularly during the jog and run phases. Relative measurement reliability was excellent during both trials (Curvilinear r = 1.00, slope = 1.03, ICC = 1.00; Shuttle r = 0.99, slope = 0.97, ICC = 0.99). Absolute measurement reliability was superior during the curvilinear trial (Curvilinear SEM = 0 m, CV = 2.16%, LOA ± 223 m; Shuttle SEM = 119 m, CV = 2.44%, LOA ± 453 m). Rapid directional change degrades the accuracy and absolute reliability of GPS distance measurement, and caution is recommended when using GPS to quantify rapid multidirectional movement patterns. PMID:24733158

  6. A Rapid Method for Determining the Concentration of Recombinant Protein Secreted from Pichia pastoris

    NASA Astrophysics Data System (ADS)

    Sun, L. W.; Zhao, Y.; Niu, L. P.; Jiang, R.; Song, Y.; Feng, H.; feng, K.; Qi, C.

    2011-02-01

    Pichia secretive expression system is one of powerful eukaryotic expression systems in genetic engineering, which is especially suitable for industrial utilization. Because of the low concentration of the target protein in initial experiment, the methods and conditions for expression of the target protein should be optimized according to the protein yield repetitively. It is necessary to set up a rapid, simple and convenient analysis method for protein expression levels instead of the generally used method such as ultrafiltration, purification, dialysis, lyophilization and so on. In this paper, acetone precipitation method was chosen to concentrate the recombinant protein firstly after comparing with four different protein precipitation methods systematically, and then the protein was analyzed by SDS-Polyacrylamide Gel Electrophoresis. The recombinant protein was determined with the feature of protein band by the Automated Image Capture and 1-D Analysis Software directly. With this method, the optimized expression conditions of basic fibroblast growth factor secreted from pichia were obtained, which is as the same as using traditional methods. Hence, a convenient tool to determine the optimized conditions for the expression of recombinant proteins in Pichia was established.

  7. Changes in gravity rapidly alter the magnitude and direction of a cellular calcium current.

    PubMed

    Salmi, Mari L; ul Haque, Aeraj; Bushart, Thomas J; Stout, Stephen C; Roux, Stanley J; Porterfield, D Marshall

    2011-05-01

    In single-celled spores of the fern Ceratopteris richardii, gravity directs polarity of development and induces a directional, trans-cellular calcium (Ca(2+)) current. To clarify how gravity polarizes this electrophysiological process, we measured the kinetics of the cellular response to changes in the gravity vector, which we initially estimated using the self-referencing calcium microsensor. In order to generate more precise and detailed data, we developed a silicon microfabricated sensor array which facilitated a lab-on-a-chip approach to simultaneously measure calcium currents from multiple cells in real time. These experiments revealed that the direction of the gravity-dependent polar calcium current is reversed in less than 25 s when the cells are inverted, and that changes in the magnitude of the calcium current parallel rapidly changing g-forces during parabolic flight on the NASA C-9 aircraft. The data also revealed a hysteresis in the response of cells in the transition from 2g to micro-g in comparison to cells in the micro-g to 2-g transition, a result consistent with a role for mechanosensitive ion channels in the gravity response. The calcium current is suppressed by either nifedipine (calcium-channel blocker) or eosin yellow (plasma membrane calcium pump inhibitor). Nifedipine disrupts gravity-directed cell polarity, but not spore germination. These results indicate that gravity perception in single plant cells may be mediated by mechanosensitive calcium channels, an idea consistent with some previously proposed models of plant gravity perception. PMID:21234599

  8. Direct laser photo-induced fluorescence determination of bisphenol A.

    PubMed

    Maroto, Alicia; Kissingou, Prosnick; Diascorn, Alexandre; Benmansour, Badr; Deschamps, Laure; Stephan, Ludovic; Cabon, Jean-Yves; Giamarchi, Philippe

    2011-11-01

    Classical photo-induced fluorescence methods are conducted in two steps: a UV irradiation step in order to form a photo-induced compound followed by its fluorimetric determination. Automated flow injection methods are frequently used for these analyses. In this work, we propose a new method of direct laser photo-induced fluorescence analysis. This new method is based on direct irradiation of the analyte in a fluorimetric cell in order to form a photo-induced fluorescent compound and its direct fluorimetric detection during a short irradiation time. Irradiation is performed with a tuneable Nd:YAG laser to select the optimal excitation wavelength and to improve the specificity. It has been applied to the determination of bisphenol A, an endocrine disrupter compound that may be a potential contaminant for food. Irradiation of bisphenol A at 230 nm produces a photo-induced compound with a much higher fluorescence quantum yield and specific excitation/emission wavelengths. In tap water, the fluorescence of bisphenol A increases linearly versus its concentration and, its determination by direct laser photo-induced fluorescence permits to obtain a low limit of detection of 17 μg L(-1). PMID:21904798

  9. A rapid and sensitive fluorometric microassay for determining cell mediated cytotoxicity to adherent growing cell lines.

    PubMed

    Krüger-Krasagakes, S; Garbe, C; Kossman, P; Orfanos, C E

    1992-11-25

    In order to measure cell mediated cytotoxicity to adherent growing cell lines in vitro more rapidly and conveniently, a fluorometric microassay was developed and results were compared with those obtained by the 51Cr release assay. The fluorometric method is based on the hydrolysis of the fluorochrome 4-methylumbelliferyl heptanoate (MUH) by intracellular esterases of viable cells. Melanoma cell monolayers were incubated with lymphokine activated killer (LAK) cells for 4 h at various effector: target (E:T) cell ratios (E:T = 16, 8, 4, 2:1). Thereafter surviving adherent melanoma cells were stained with MUH for 30 min and fluorescence was measured directly in a 96 well plate reader. For the calculation of LAK cell cytotoxicity fluorescence values were corrected for the number of nonspecifically detached tumor cells during the washes and the number of nonspecifically adherent LAK cells. Using identical target and effector cell preparations both assays showed a nearly proportional increase of percentage cytotoxicity with rising numbers of lymphocytes. Compared with the 51Cr release assay, however, higher cytotoxicity values were obtained with the fluorometric MUH microassay: 57% with MUH versus 26% with 51Cr and 39% versus 14% for cell lines StML-11 and SKMel-28, respectively (E:T ratio = 16:1). The higher cytotoxicity rates obtained with the fluorometric MUH microassay were not due to the additional 30 min staining with MUH or due to nonspecific hydrolysis of MUH by extracellular esterases released from damaged cells, as could be shown by a series of experiments. In conclusion, a simple and rapid fluorometric microassay has been developed showing reliable reproducibility and a higher sensitivity compared with the 51Cr release assay for the determination of cellular cytotoxicity to adherent growing cell lines, avoiding hazardous radioactive labels. PMID:1431156

  10. Rapid monitoring of soil, smears, and air dusts by direct large-area alpha spectrometry

    SciTech Connect

    Sill, C.W.

    1992-01-01

    Experimental conditions to permit rapid monitoring of soils, smears, and air dusts for transuranic (TRU) radionuclides under field conditions are described. The monitoring technique involves direct measurement of alpha emitters by alpha spectrometry using a large-area detector to identify and quantify the radionuclides present. The direct alpha spectrometry employs a circular gridded ionization chamber 35 cm in diameter which accommodates either a circular sample holder 25 cm in diameter or a rectangular one 20 by 25 cm (8 by 10 in.). Soils or settled dusts are finely ground, suspended in 30% ethanol, and sprayed onto a 25-cm stainless steel dish. Air dusts are collected with a high-volume sampler onto 20- by 25-cm membrane filters. Removable contamination is collected from surfaces onto a 20- by 25-cm filter using an 18-cm (7-in.) paint roller to hold the large filter in contact with the surface during sample collection. All three types of samples are then counted directly in the alpha spectrometer and no other sample preparation is necessary. Some results obtained are described.

  11. A Molecular Imaging Paradigm to Rapidly Profile Response to Angiogenesis-directed Therapy in Small Animals

    PubMed Central

    Virostko, John; Xie, Jingping; Hallahan, Dennis E.; Arteaga, Carlos L.; Gore, John C.; Manning, H. Charles

    2009-01-01

    Purpose The development of novel angiogenesis-directed therapeutics is hampered by the lack of non-invasive imaging metrics capable of assessing treatment response. We report the development and validation of a novel molecular imaging paradigm to rapidly assess response to angiogenesis-directed therapeutics in preclinical animal models. Procedures A monoclonal antibody-based optical imaging probe targeting vascular endothelial growth factor receptor-2 (VEGFR2) expression was synthesized and evaluated in vitro and in vivo via multispectral fluorescence imaging. Results The optical imaging agent demonstrated specificity for the target receptor in cultured endothelial cells and in vivo. The agent exhibited significant accumulation within 4T1 xenograft tumors. Mice bearing 4T1 xenografts and treated with sunitinib exhibited both tumor growth arrest and decreased accumulation of NIR800-αVEGFR2ab compared to untreated cohorts (p=0.0021). Conclusions Molecular imaging of VEGFR2 expression is a promising non-invasive biomarker for assessing angiogenesis and evaluating the efficacy of angiogenesis-directed therapies. PMID:19130143

  12. Rapid and simultaneous determination of Strontium-89 and Strontium-90 in seawater.

    PubMed

    Tayeb, Michelle; Dai, Xiongxin; Sdraulig, Sandra

    2016-03-01

    A rapid method has been developed for the direct determination of radiostrontium ((89)Sr and (90)Sr) released in seawater in the early phase of an accident. The method employs a fast and effective pre-concentration of radiostrontium by Sr-Ca co-precipitation followed by separation of radiostrontium using extraction chromatography technique. Radiostrontium is effectively separated in the presence of excessive dominant salts of seawater. Čerenkov and liquid scintillation assay (LSA) techniques are used to determine (89)Sr and (90)Sr. Sample preparation time is approximately 4 h for a set of 10 samples. The method was validated using spiked seawater samples at various activity ratios of (89)Sr:(90)Sr ranging from 1:10 to 9:1. The mean chemical recovery of Sr was 85 ± 3%. (90)Sr showed variable relative bias which enhanced with increasing ratio of (89)Sr:(90)Sr and was in the range ± 21%. The highest biases of (90)Sr determination were due to lower activity concentrations of (90)Sr and are regarded as acceptable in emergency situations with elevated levels of radiostrontium in the sample. The minimum detectable concentration (MDC) of (90)Sr and (89)Sr varied at different (89)Sr:(90)Sr ratios. For 0.1 L seawater and 15 min counting time on a low background Hidex liquid scintillation counter (LSC), the MDC of (90)Sr was in the range of 1.7-3.5 Bq L(-1) and MDC of (89)Sr was in the range 0.5-2.4 Bq L(-1). PMID:26803402

  13. Direct determination of quantum efficiency of semiconducting films

    DOEpatents

    Faughnan, B.W.; Hanak, J.J.

    Photovoltaic quantum efficiency of semiconductor samples is determined directly, without requiring that a built-in photovoltage be generated by the sample. Electrodes are attached to the sample so as to form at least one Schottky barrier therewith. When illuminated, the generated photocurrent carriers are collected by an external bias voltage impressed across the electrodes. The generated photocurrent is measured, and photovoltaic quantum efficiency is calculated therefrom.

  14. Direct determination of quantum efficiency of semiconducting films

    DOEpatents

    Faughnan, Brian W.; Hanak, Joseph J.

    1986-01-01

    Photovoltaic quantum efficiency of semiconductor samples is determined directly, without requiring that a built-in photovoltage be generated by the sample. Electrodes are attached to the sample so as to form at least one Schottky barrier therewith. When illuminated, the generated photocurrent carriers are collected by an external bias voltage impressed across the electrodes. The generated photocurrent is measured, and photovoltaic quantum efficiency is calculated therefrom.

  15. A General-applications Direct Global Matrix Algorithm for Rapid Seismo-acoustic Wavefield Computations

    NASA Technical Reports Server (NTRS)

    Schmidt, H.; Tango, G. J.; Werby, M. F.

    1985-01-01

    A new matrix method for rapid wave propagation modeling in generalized stratified media, which has recently been applied to numerical simulations in diverse areas of underwater acoustics, solid earth seismology, and nondestructive ultrasonic scattering is explained and illustrated. A portion of recent efforts jointly undertaken at NATOSACLANT and NORDA Numerical Modeling groups in developing, implementing, and testing a new fast general-applications wave propagation algorithm, SAFARI, formulated at SACLANT is summarized. The present general-applications SAFARI program uses a Direct Global Matrix Approach to multilayer Green's function calculation. A rapid and unconditionally stable solution is readily obtained via simple Gaussian ellimination on the resulting sparsely banded block system, precisely analogous to that arising in the Finite Element Method. The resulting gains in accuracy and computational speed allow consideration of much larger multilayered air/ocean/Earth/engineering material media models, for many more source-receiver configurations than previously possible. The validity and versatility of the SAFARI-DGM method is demonstrated by reviewing three practical examples of engineering interest, drawn from ocean acoustics, engineering seismology and ultrasonic scattering.

  16. Flies evade looming targets by executing rapid visually directed banked turns.

    PubMed

    Muijres, Florian T; Elzinga, Michael J; Melis, Johan M; Dickinson, Michael H

    2014-04-11

    Avoiding predators is an essential behavior in which animals must quickly transform sensory cues into evasive actions. Sensory reflexes are particularly fast in flying insects such as flies, but the means by which they evade aerial predators is not known. Using high-speed videography and automated tracking of flies in combination with aerodynamic measurements on flapping robots, we show that flying flies react to looming stimuli with directed banked turns. The maneuver consists of a rapid body rotation followed immediately by an active counter-rotation and is enacted by remarkably subtle changes in wing motion. These evasive maneuvers of flies are substantially faster than steering maneuvers measured previously and indicate the existence of sensory-motor circuitry that can reorient the fly's flight path within a few wingbeats. PMID:24723606

  17. Determinants of direct costs in Dutch rheumatoid arthritis patients

    PubMed Central

    Verstappen, S; Verkleij, H; Bijlsma, J; Buskens, E; Kruize, A; Heurkens, A; van der Veen, M J; Jacobs, J

    2004-01-01

    Objectives: To estimate annual direct costs in four distinct disease duration groups (0 to ⩽2, 2 to ⩽6, 6 to ⩽10, and >10 years) of patients with rheumatoid arthritis (RA), to determine predictors of high costs and to describe characteristics of patients with high and with low costs. Methods: A questionnaire assessing RA related care and resource utilisation rates and costs was completed by 615 RA patients. Predictive variables for incurred costs, as observed during the first year after disease onset, were determined in a subgroup of patients (n = 347). Results: Mean (median) annual direct costs for the four groups with increasing disease duration were respectively: €5235 (2923), €3930 (1968), €4664 (1952), and €8243 (3778), (p < 0.05). During the first 2 years of the disease total direct costs comprised mainly of consultations with heatlhcare workers (28%). After 10 years, devices and adaptations were the main contributors (40%) to total costs. Positive rheumatoid factor results at the time of diagnosis and deterioration of functional disability in the first year of disease were predictors of high costs later on in the course of the disease. Conclusion: Annual direct costs among patients with a disease duration of less than 2 years tend to be lower among patients with a disease duration of between 2 and 10 years than among patients with a disease duration of more than 10 years. In addition, the proportional distribution of different cost categories to total costs increases with with increasing disease duration. PMID:15194577

  18. Rapid Method for the Determination of the Stable Oxygen Isotope Ratio of Water in Alcoholic Beverages.

    PubMed

    Wang, Daobing; Zhong, Qiding; Li, Guohui; Huang, Zhanbin

    2015-10-28

    This paper demonstrates the first successful application of an online pyrolysis technique for the direct determination of oxygen isotope ratios (δ(18)O) of water in alcoholic beverages. Similar water concentrations in each sample were achieved by adjustment with absolute ethyl alcohol, and then a fixed GC split ratio can be used. All of the organic ingredients were successfully separated from the analyte on a CP-PoraBond Q column and subsequently vented out, whereas water molecules were transferred into the reaction furnace and converted to CO. With the system presented, 15-30 μL of raw sample was diluted and can be analyzed repeatedly; the analytical precision was better than 0.4‰ (n = 5) in all cases, and more than 50 injections can be made per day. No apparent memory effect was observed even if water samples were injected using the same syringe; a strong correlation (R(2) = 0.9998) was found between the water δ(18)O of measured sample and that of working standards. There was no significant difference (p > 0.05) between the mean δ(18)O value and that obtained by the traditional method (CO2-water equilibration/isotope ratio mass spectrometry) and the newly developed method in this study. The advantages of this new method are its rapidity and straightforwardness, and less test portion is required. PMID:26373434

  19. Determination of very rapid molecular rotation by using the central electron paramagnetic resonance line.

    PubMed

    Kurban, Mark R

    2013-02-21

    Picosecond rotational correlation times of perdeuterated tempone (PDT) are found in alkane and aromatic liquids by directly using the spectral width of the central electron paramagnetic resonance line. This is done by mathematically eliminating the nonsecular spectral density from the spectral parameter equations, thereby removing the need to assume a particular form for it. This is preferable to fitting a constant correction factor to the spectral density, because such a factor does not fit well in the low picosecond range. The electron-nuclear spin dipolar interaction between the probe and solvent is shown to be negligible for the very rapid rotation of PDT in these liquids at the temperatures of the study. The rotational correlation times obtained with the proposed method generally agree to within experimental uncertainty with those determined by using the traditional parameters. Using the middle line width offers greater precision and smoother trends. Previous work with the central line width is discussed, and past discrepancies are explained as possibly resulting from residual inhomogeneous broadening. The rotational correlation time almost forms a common curve across all of the solvents when plotted with respect to isothermal compressibility, which shows the high dependence of rotation on liquid free volume. PMID:23320940

  20. Determination of Very Rapid Molecular Rotation by Using the Central EPR Line

    PubMed Central

    Kurban, Mark R.

    2014-01-01

    Picosecond rotational correlation times of perdeuterated tempone (PDT) are found in alkane and aromatic liquids by directly using the spectral width of the central electron paramagnetic resonance line. This is done by mathematically eliminating the non-secular spectral density from the spectral parameter equations, thereby removing the need to assume a particular form for it. This is preferable to fitting a constant correction factor to the spectral density, because such a factor does not fit well in the low picosecond range. The electron-nuclear spin dipolar interaction between the probe and solvent is shown to be negligible for the very rapid rotation of PDT in these liquids at the temperatures of the study. The rotational correlation times obtained with the proposed method generally agree to within experimental uncertainty with those determined by using the traditional parameters. Using the middle line width offers greater precision and smoother trends. Previous work with the central line width is discussed, and past discrepancies are explained as possibly resulting from residual inhomogeneous broadening. The rotational correlation time almost forms a common curve across all of the solvents when plotted with respect to isothermal compressibility, which shows the high dependence of rotation on liquid free volume. PMID:23320940

  1. Study on the fast optimal direction determination for missile-borne star sensor

    NASA Astrophysics Data System (ADS)

    Yang, Jing; Kong, Long-tao; Xiong, Kai

    2013-12-01

    To ensure the accuracy and effectiveness of missile-borne star sensor for attitude determination, its optical axis direction must be adjusted in real time to avoid the stray light effectively and obtain star image with high-quality. In this paper, a fast optimal direction determination method that can be applied online in engineering is studied. Take the range of missile maneuver into consider, the proposed method solves the optimal direction of optical axis which can make star sensor obtain the best star image for star identification within the visible sky that avoids stray light. In the optical axis optimization model established, for a star sensor with given specification, the optimization indexes include the stars number and their mean magnitude of a star image obtained at a given direction, the control cost to reach the optimal direction from current status. The constraints include invisible sky, stray light etc. For such a complex nonlinear optimization problem without analytical solutions, the combination of enumeration method and table look-up method is employed to obtain solution rapidly for engineering applications. The stray light model is validated by comparing the simulation results with Satellite Tool Kit (STK). Simulation results show that the optimal direction determined by the proposed method can significantly improve the star image's quality and the optimization speed is fast enough to meet the requirement of online applications.

  2. A protocol for direct and rapid multiplex PCR amplification on forensically relevant samples.

    PubMed

    Verheij, Saskia; Harteveld, Joyce; Sijen, Titia

    2012-03-01

    Forensic DNA typing involves a multi-step workflow. Steps include DNA isolation, quantification, amplification of a set of short tandem repeat (STR) markers, separation of polymerase chain reaction (PCR) products by capillary electrophoresis (CE) and DNA profile analysis and interpretation. With that, the process takes around 10-12h. For several scenarios it may be very valuable to speed up this process and obtain an interpretable DNA profile, suited to search a DNA database, within a few hours. For instance in cases of national security, abduction with danger of life, risk of repetition by a serial perpetrator or when custody time of suspects is limited. By a direct and rapid PCR approach we reduced the total DNA profiling time to 2-3h after which genotyping information for the 10 STR markers plus the amelogenin (AMEL) marker present in the commercially available AmpFℓSTR(®) SGM Plus™ (SGM+) profiling kit is obtained. This reduction in time is achieved by using the following elements: (1) the inhibitor tolerant, highly processive Phusion(®) Flash DNA polymerase; (2) a modified, non-adenylated allelic ladder; (3) the quick PIKO(®) thermal cycler system with ultra-thin walled reaction tubes; (4) profile interpretation guidelines with an increased allele calling threshold, modified stutter ratios and marked low-level artefact peaks and (5) regulation of sample input by the use of mini-tapes that lift a limited amount of cell material from swabs or fabrics. The procedure is specifically effective for high level DNA, single source samples such as samples containing saliva, blood, semen and hair roots. Success rates, defined as a complete DNA profile, depend on stain type and surface. Due to the use of tape lifting as the sampling technique, the swab or fabric remains dry and intact and can be analyzed at a later stage using regular procedures. Validation experiments were performed which showed that the protocol effectively instructs researchers unfamiliar with

  3. Direct determination of the refractive index of natural multilayer systems

    NASA Astrophysics Data System (ADS)

    Yoshioka, Shinya; Kinoshita, Shuichi

    2011-05-01

    It is well known that the metal-like strong reflection observed in the elytra of some kinds of beetles is produced by multilayer thin-film interference. For the quantitative analyses of the structural colors in these elytra, it is necessary to know accurate values of the refractive indices of the materials that comprise the multilayer structure. However, index determination is not an easy task: The elytron surface is not flat but curved and usually contains many irregular bumps, which cause scattering loss. These structural characteristics prevent us from directly applying conventional optical techniques for index determination, such as ellipsometry, since these techniques require a perfectly specular surface. In this paper, we report a new experimental procedure that can directly determine the refractive indices of individual layers in natural multilayer systems. This procedure involves semi-frontal thin-sectioning of the sample and subsequent optical examinations using a microspectrophotometer. We demonstrate that the complex refractive index and its wavelength dependence can be successfully determined for one kind of beetle.

  4. Rapid Microcystin Determination Using a Paper Spray Ionization Method with a Time-of-Flight Mass Spectrometry System.

    PubMed

    Zhu, Xiaoqiang; Huang, Zhengxu; Gao, Wei; Li, Xue; Li, Lei; Zhu, Hui; Mo, Ting; Huang, Bao; Zhou, Zhen

    2016-07-13

    The eutrophication of surface water sources and climate changes have resulted in an annual explosion of cyanobacterial blooms in many irrigating and drinking water resources. To decrease health risks to the public, a rapid real time method for the synchronous determination of two usually harmful microcystins (MC-RR and MC-LR) in environmental water samples was built by employing a paper spray ionization method coupled with a time-of-flight mass spectrometer system. With this approach, direct analysis of microcystin mixtures without sample preparation has been achieved. Rapid detection was performed, simulating the release process of microcystins in reservoir water samples, and the routine detection frequency was every three minutes. The identification time of microcystins was reduced from several hours to a few minutes. The limit of detection is 1 μg/L, and the limit of quantitation is 3 μg/L. This method displays the ability for carrying out rapid, direct, and high-throughput experiments for determination of microcystins, and it would be of significant interest for environmental and food safety applications. PMID:27345366

  5. Rapid, Time-Division Multiplexed, Direct Absorption- and Wavelength Modulation-Spectroscopy

    PubMed Central

    Klein, Alexander; Witzel, Oliver; Ebert, Volker

    2014-01-01

    We present a tunable diode laser spectrometer with a novel, rapid time multiplexed direct absorption- and wavelength modulation-spectroscopy operation mode. The new technique allows enhancing the precision and dynamic range of a tunable diode laser absorption spectrometer without sacrificing accuracy. The spectroscopic technique combines the benefits of absolute concentration measurements using calibration-free direct tunable diode laser absorption spectroscopy (dTDLAS) with the enhanced noise rejection of wavelength modulation spectroscopy (WMS). In this work we demonstrate for the first time a 125 Hz time division multiplexed (TDM-dTDLAS-WMS) spectroscopic scheme by alternating the modulation of a DFB-laser between a triangle-ramp (dTDLAS) and an additional 20 kHz sinusoidal modulation (WMS). The absolute concentration measurement via the dTDLAS-technique allows one to simultaneously calibrate the normalized 2f/1f-signal of the WMS-technique. A dTDLAS/WMS-spectrometer at 1.37 μm for H2O detection was built for experimental validation of the multiplexing scheme over a concentration range from 50 to 3000 ppmV (0.1 MPa, 293 K). A precision of 190 ppbV was achieved with an absorption length of 12.7 cm and an averaging time of two seconds. Our results show a five-fold improvement in precision over the entire concentration range and a significantly decreased averaging time of the spectrometer. PMID:25405508

  6. Development of a rapid diagnostic test for pertussis: direct detection of pertussis toxin in respiratory secretions.

    PubMed Central

    Friedman, R L; Paulaitis, S; McMillan, J W

    1989-01-01

    Monoclonal antibodies (MAb) were produced against the specific Bordetella pertussis antigen pertussis toxin (PT). In preliminary studies, one MAb (IB12) was selected and used in an enzyme-linked dot blot immunoassay to evaluate the ability of the method to detect known amounts of PT in control experiments and to test its potential for direct detection of PT in nasopharyngeal secretion (NP) specimens from patients with confirmed cases of whooping cough. The dot blot assay was able to detect PT at levels as low as 10 ng per dot in either buffer or control NP specimens. The assay demonstrated specificity, reacting only with dot blots of whole B. pertussis and not Bordetella bronchiseptica, Bordetella parapertussis, or other bacterial strains. In preliminary studies, NP aspirate, swab, and wash specimens were compared. The specimen of choice was found to be the NP aspirate, for which 100% positive results were found in the assay. These initial studies suggest that the dot blot immunoassay in which a MAb is used for direct detection of PT in NP specimens may be useful as a rapid diagnostic test for pertussis. Images PMID:2808670

  7. Digital Direct-to-Consumer Advertising: A Perfect Storm of Rapid Evolution and Stagnant Regulation

    PubMed Central

    Mackey, Tim K.

    2016-01-01

    The adoption and use of digital forms of direct-to-consumer advertising (also known as "eDTCA") is on the rise. At the same time, the universe of eDTCA is expanding, as technology on Internet-based platforms continues to evolve, from static websites, to social media, and nearly ubiquitous use of mobile devices. However, little is known about how this unique form of pharmaceutical marketing impacts consumer behavior, public health, and overall healthcare utilization. The study by Kim analyzing US Food and Drug Administration (FDA) notices of violations (NOVs) and warning letters regarding online promotional activities takes us in the right direction, but study results raise as many questions as it does answers. Chief among these are unanswered concerns about the unique regulatory challenges posed by the "disruptive" qualities of eDTCA, and whether regulators have sufficient resources and oversight powers to proactively address potential violations. Further, the globalization of eDTCA via borderless Internet-based technologies raises larger concerns about the potential global impact of this form of health marketing unique to only the United States and New Zealand. Collectively, these challenges make it unlikely that regulatory science will be able to keep apace with the continued rapid evolution of eDTCA unless more creative policy solutions are explored. PMID:27239871

  8. Sensitive and rapid detection of Chlamydia trachomatis by recombinase polymerase amplification directly from urine samples.

    PubMed

    Krõlov, Katrin; Frolova, Jekaterina; Tudoran, Oana; Suhorutsenko, Julia; Lehto, Taavi; Sibul, Hiljar; Mäger, Imre; Laanpere, Made; Tulp, Indrek; Langel, Ülo

    2014-01-01

    Chlamydia trachomatis is the most common sexually transmitted human pathogen. Infection results in minimal to no symptoms in approximately two-thirds of women and therefore often goes undiagnosed. C. trachomatis infections are a major public health concern because of the potential severe long-term consequences, including an increased risk of ectopic pregnancy, chronic pelvic pain, and infertility. To date, several point-of-care tests have been developed for C. trachomatis diagnostics. Although many of them are fast and specific, they lack the required sensitivity for large-scale application. We describe a rapid and sensitive form of detection directly from urine samples. The assay uses recombinase polymerase amplification and has a minimum detection limit of 5 to 12 pathogens per test. Furthermore, it enables detection within 20 minutes directly from urine samples without DNA purification before the amplification reaction. Initial analysis of the assay from clinical patient samples had a specificity of 100% (95% CI, 92%-100%) and a sensitivity of 83% (95% CI, 51%-97%). The whole procedure is fairly simple and does not require specific machinery, making it potentially applicable in point-of-care settings. PMID:24331366

  9. Rapid label-free determination of ketamine in whole blood using secondary ion mass spectrometry.

    PubMed

    Liao, Hua-Yang; Chen, Jung-Hsuan; Shyue, Jing-Jong; Shun, Chia-Tung; Chen, Huei-Wen; Liao, Su-Wei; Hong, Chih-Kang; Chen, Pai-Shan

    2015-10-01

    A fast and accurate drug screening to identify the possible presence of a wide variety of pharmaceutical and illicit drugs is increasingly requested in forensic and clinical toxicology. The current first-line screening relies on immunoassays. They determine only certain common drugs of which antibodies are commercially available. To address the issue, a rapid screening using secondary ion mass spectrometry (SIMS) has been developed. In the study, SIMS directly analyzed ketamine in whole blood without any pretreatment. While the untreated blood has a complicated composition, principal-components analysis (PCA) is used to detect unknown specimens by building up an analytical model from blank samples which were spiked with ketamine at 100 ng mL(-1), to simulate the presence of ketamine. Each characteristics m/z is normalized and scaled by multiplying the root square of intensity and square of corresponding m/z, developed by National Institute of Standards and Technology (NIST). Using linear regression and the result of PCA, this study enables to correctly distinguish ketamine positive and negative groups in an unknown set of specimens. The quantity of ketamine in an unknown set was determined using gas chromatography-mass spectrometry (GC-MS) as the reference methodology. Instead limited by commercially available antibodies, SIMS detects target molecules straight despite the label-free detection capabilities of SIMS, additional data processing (here, PCA) can be used to fully analyse the produced data, which extends the range of analytes of interest on drug screening. Furthermore, extremely low sample volume, 5 µL, is required owing to the high spatial resolution of SIMS. In addition, while the whole blood is analyzed within 3 min, the whole analysis has been shortened significantly and high throughput can be achieved. PMID:26078127

  10. Extremely rapid directional change during Matuyama-Brunhes geomagnetic polarity reversal

    NASA Astrophysics Data System (ADS)

    Sagnotti, Leonardo; Scardia, Giancarlo; Giaccio, Biagio; Liddicoat, Joseph C.; Nomade, Sebastien; Renne, Paul R.; Sprain, Courtney J.

    2014-11-01

    We report a palaeomagnetic investigation of the last full geomagnetic field reversal, the Matuyama-Brunhes (M-B) transition, as preserved in a continuous sequence of exposed lacustrine sediments in the Apennines of Central Italy. The palaeomagnetic record provides the most direct evidence for the tempo of transitional field behaviour yet obtained for the M-B transition. 40Ar/39Ar dating of tephra layers bracketing the M-B transition provides high-accuracy age constraints and indicates a mean sediment accumulation rate of about 0.2 mm yr-1 during the transition. Two relative palaeointensity (RPI) minima are present in the M-B transition. During the terminus of the upper RPI minimum, a directional change of about 180 ° occurred at an extremely fast rate, estimated to be less than 2 ° per year, with no intermediate virtual geomagnetic poles (VGPs) documented during the transit from the southern to northern hemisphere. Thus, the entry into the Brunhes Normal Chron as represented by the palaeomagnetic directions and VGPs developed in a time interval comparable to the duration of an average human life, which is an order of magnitude more rapid than suggested by current models. The reported investigation therefore provides high-resolution integrated palaeomagnetic and radioisotopic data that document the fine details of the anatomy and tempo of the M-B transition in Central Italy that in turn are crucial for a better understanding of Earth's magnetic field, and for the development of more sophisticated models that are able to describe its global structure and behaviour.

  11. Rapid Whole-Genome Sequencing of Mycobacterium tuberculosis Isolates Directly from Clinical Samples

    PubMed Central

    Brown, Amanda C.; Einer-Jensen, Katja; Holdstock, Jolyon; Houniet, Darren T.; Chan, Jacqueline Z. M.; Depledge, Daniel P.; Nikolayevskyy, Vladyslav; Broda, Agnieszka; Stone, Madeline J.; Christiansen, Mette T.; Williams, Rachel; McAndrew, Michael B.; Tutill, Helena; Brown, Julianne; Melzer, Mark; Rosmarin, Caryn; McHugh, Timothy D.; Shorten, Robert J.; Drobniewski, Francis; Speight, Graham; Breuer, Judith

    2015-01-01

    The rapid identification of antimicrobial resistance is essential for effective treatment of highly resistant Mycobacterium tuberculosis. Whole-genome sequencing provides comprehensive data on resistance mutations and strain typing for monitoring transmission, but unlike for conventional molecular tests, this has previously been achievable only from cultures of M. tuberculosis. Here we describe a method utilizing biotinylated RNA baits designed specifically for M. tuberculosis DNA to capture full M. tuberculosis genomes directly from infected sputum samples, allowing whole-genome sequencing without the requirement of culture. This was carried out on 24 smear-positive sputum samples, collected from the United Kingdom and Lithuania where a matched culture sample was available, and 2 samples that had failed to grow in culture. M. tuberculosis sequencing data were obtained directly from all 24 smear-positive culture-positive sputa, of which 20 were of high quality (>20× depth and >90% of the genome covered). Results were compared with those of conventional molecular and culture-based methods, and high levels of concordance between phenotypical resistance and predicted resistance based on genotype were observed. High-quality sequence data were obtained from one smear-positive culture-negative case. This study demonstrated for the first time the successful and accurate sequencing of M. tuberculosis genomes directly from uncultured sputa. Identification of known resistance mutations within a week of sample receipt offers the prospect for personalized rather than empirical treatment of drug-resistant tuberculosis, including the use of antimicrobial-sparing regimens, leading to improved outcomes. PMID:25972414

  12. A rapid direct telomerase assay method using 96-well streptavidin plates.

    PubMed

    Francis, Rawle; Friedman, Simon H

    2002-05-01

    We have developed a high-throughput direct assay methodfor the assay of telomerase activity that improves on previous direct telomerase assays in two ways that allow larger numbers of samples to be conveniently processed: (i) 96-well streptavidin coated plates are used to bind and wash biotinylated primer extension products from the telomerase assay, as opposed to tubes containing streptavidin-coated magnetic beads; and (ii) storage phosphor-imagery is used instead of film autoradiography to detect telomerase products after being washed and released from the streptavidin-derivatized matrix. This method improves on previous direct assay methods using magnetic beads by allowing larger numbers of samples to be conveniently assayed. Also, the total activity of the radiolabeled nucleotides used in this procedure is significantly lower than that used in standard direct telomerase assays, lowering costs and exposure to radioactivity. We have validated the assay by repeating, in triplicate, the IC50 determination of rivanol, our previously identified telomerase inhibitor. PMID:12019789

  13. Evaluation of Three Rapid Diagnostic Methods for Direct Identification of Microorganisms in Positive Blood Cultures

    PubMed Central

    Martinez, Raquel M.; Bauerle, Elizabeth R.; Fang, Ferric C.

    2014-01-01

    The identification of organisms from positive blood cultures generally takes several days. However, recently developed rapid diagnostic methods offer the potential for organism identification within only a few hours of blood culture positivity. In this study, we evaluated the performance of three commercial methods to rapidly identify organisms directly from positive blood cultures: QuickFISH (AdvanDx, Wolburn, MA), Verigene Gram-Positive Blood Culture (BC-GP; Nanosphere, Northbrook, IL), and matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) with Sepsityper processing (Bruker Daltonics, Billerica, MA). A total of 159 blood cultures (VersaTREK Trek Diagnostic Systems, Cleveland, OH) positive for Gram-positive and Gram-negative bacteria as well as yeast were analyzed with QuickFISH and MALDI-TOF MS. In all, 102 blood cultures were analyzed using the BC-GP assay. For monomicrobial cultures, we observed 98.0% concordance with routine methods for both QuickFISH (143/146) and the BC-GP assay (93/95). MALDI-TOF MS demonstrated 80.1% (117/146) and 87.7% (128/146) concordance with routine methods to the genus and species levels, respectively. None of the methods tested were capable of consistently identifying polymicrobial cultures in their entirety or reliably differentiating Streptococcus pneumoniae from viridans streptococci. Nevertheless, the methods evaluated in this study are convenient and accurate for the most commonly encountered pathogens and have the potential to dramatically reduce turnaround time for the provision of results to the treating physician. PMID:24808235

  14. Determination of HIV status in African adults with discordant HIV rapid tests

    PubMed Central

    Fogel, Jessica M.; Piwowar-Manning, Estelle; Donohue, Kelsey; Cummings, Vanessa; Marzinke, Mark A.; Clarke, William; Breaud, Autumn; Fiamma, Agnès; Donnell, Deborah; Kulich, Michal; Mbwambo, Jessie K. K.; Richter, Linda; Gray, Glenda; Sweat, Michael; Coates, Thomas J.; Eshleman, Susan H.

    2015-01-01

    Background In resource-limited settings, HIV infection is often diagnosed using two rapid tests. If the results are discordant, a third tie-breaker test is often used to determine HIV status. This study characterized samples with discordant rapid tests and compared different testing strategies for determining HIV status in these cases. Methods Samples were previously collected from 173 African adults in a population-based survey who had discordant rapid test results. Samples were classified as HIV positive or HIV negative using a rigorous testing algorithm that included two fourth-generation tests, a discriminatory test, and two HIV RNA tests. Tie-breaker tests were evaluated, including: rapid tests (one performed in-country), a third-generation enzyme immunoassay (EIA), and two fourth-generation tests. Selected samples were further characterized using additional assays. Results Twenty-nine (16.8%) samples were classified as HIV positive; 24 (82.8%) of those samples had undetectable HIV RNA. Antiretroviral drugs were detected in one sample. Sensitivity was 8.3%–43% for the rapid tests; 24.1% for the third-generation EIA; 95.8% and 96.6% for the fourth-generation tests. Specificity was lower for the fourth-generation tests than the other tests. Accuracy ranged from 79.5–91.3%. Conclusions In this population-based survey, most HIV-infected adults with discordant rapid tests were virally suppressed without antiretroviral drugs. Use of individual assays as tie-breaker tests was not a reliable method for determining HIV status in these individuals. More extensive testing algorithms that use a fourth-generation screening test with a discriminatory test and HIV RNA test are preferable for determining HIV status in these cases. PMID:25835607

  15. A rapid method for determining salinomycin and monensin sensitivity in Eimeria tenella

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Standard methods of determining the ionophore sensitivity of Eimeria rely on infecting chickens with an isolate or a mixture of Eimeria spp. oocysts in the presence of different anti-coccidial drugs. The purpose of this study was to develop a rapid in vitro method for assessing salinomycin and mone...

  16. 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.

  17. Rapid methods of determining cooling rates of iron and stony iron meteorites

    USGS Publications Warehouse

    Short, J.M.; Goldstein, J.I.

    1967-01-01

    Two rapid and simple methods have been developed for determining the approximate cooling rates of iron and stony-iron meteorites in which kamacite formed by diffusion-controlled growth along planar fronts. The first method requires only measurements of the mean kamacite bandwidth and the bulk nickel content. The second method requires the determination of the nickel composition near the taenite-kamacite interface with an electron microprobe.

  18. Rapid Detection of Thrombin and Other Protease Activity Directly in Whole Blood

    NASA Astrophysics Data System (ADS)

    Yu, Johnson Chung Sing

    Thrombin is a serine protease that plays a key role in the clotting cascade to promote hemostasis following injury to the endothelium. From a clinical diagnostic perspective, in-vivo thrombin activity is linked to various blood clotting disorders, as well as cardiovascular disease (DVT, arteriosclerosis, etc). Thus, the ability to rapidly measure protease activity directly in whole blood will provide important new diagnostics, and clinical researchers with a powerful tool to further elucidate the relationship between circulating protease levels and disease. The ultimate goal is to design novel point of care (POC) diagnostic devices that are capable of monitoring protease activities directly in whole blood and biological sample. A charge-changing substrate specific to the thrombin enzyme was engineered and its functionality was confirmed by a series of experiments. This led to the preliminary design, construction, and testing of two device platforms deemed fully functional for the electrophoretic separation and focusing of charged peptide fragments. The concept of using the existing charge-changing substrate platform for bacterial protease detection was also investigated. Certain strains of E coli are associated with severe symptoms such as abdominal cramps, bloody diarrhea, and vomiting. The OmpT protease is expressed on the outer membrane of E coli and plays a role in the cleavage of antimicrobial peptides, the degradation of recombinant heterologous proteins, and the activation of plasminogen in the host. Thus, a synthetic peptide substrate specific to the OmpT protease was designed and modeled for the purpose of detecting E coli in biological sample.

  19. Rapid determination of Faraday rotation in optical glasses by means of secondary Faraday modulator.

    PubMed

    Sofronie, M; Elisa, M; Sava, B A; Boroica, L; Valeanu, M; Kuncser, V

    2015-05-01

    A rapid high sensitive method for determining the Faraday rotation of optical glasses is proposed. Starting from an experimental setup based on a Faraday rod coupled to a lock-in amplifier in the detection chain, two methodologies were developed for providing reliable results on samples presenting low and large Faraday rotations. The proposed methodologies were critically discussed and compared, via results obtained in transmission geometry, on a new series of aluminophosphate glasses with or without rare-earth doping ions. An example on how the method can be used for a rapid examination of the optical homogeneity of the sample with respect to magneto-optical effects is also provided. PMID:26026534

  20. A simplified CARS measurement system for rapid determination of temperature and oxygen concentration

    NASA Technical Reports Server (NTRS)

    Fujii, Shoichi

    1987-01-01

    A new spectroscopic concept for the rapid determination of temperature and oxygen concentration by CARS (Coherent Anti-Stokes Raman Spectroscopy) was described. The ratio of two spectral regions in the broadband Q-branch spectrum was detected by photomultipliers in a monochromator, which ratio depends on temperature and species concentration. The comparison of the measured data with theory was made using a flat flame burner and an electric furnace, with reasonable results. Various optical techniques for alignment were introduced including a highly efficient, stable dye oscillator. The combination of the spectroscopic concept and the optical techniques will make the CARS measurement system rapid in data processing and simple in optical parts.

  1. Rapid method to determine actinides and 89/90Sr in limestone and marble samples

    DOE PAGESBeta

    Maxwell, Sherrod L.; Culligan, Brian; Hutchison, Jay B.; Utsey, Robin C.; Sudowe, Ralf; McAlister, Daniel R.

    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.

  2. Simple, rapid method for direct isolation of nucleic acids from aquatic environments.

    PubMed Central

    Somerville, C C; Knight, I T; Straube, W L; Colwell, R R

    1989-01-01

    Direct isolation of nucleic acids from the environment may be useful in several respects, including the estimation of total biomass, detection of specific organisms and genes, estimations of species diversity, and cloning applications. We have developed a method that facilitates the concentration of microorganisms from aquatic samples and the extraction of their nucleic acids. Natural water samples of 350 to greater than 1,000 ml are concentrated on a single cylindrical filter membrane (type SVGS01015; Millipore Corp., Bedford, Mass.), and cell lysis and proteolysis are carried out within the filter housing. Crude, high-molecular-weight nucleic acid solutions are then drawn off the filter. These solutions can be immediately analyzed, concentrated, or purified, depending on the intended application. The method is simple, rapid, and economical and provides high-molecular-weight chromosomal DNA, plasmid DNA, and speciated RNAs which comigrate with 5S, 16S, and 23S rRNAs. The methods presented here should prove useful in studying both the ecology and the phylogeny of microbes that resist classical culture methods. Images PMID:2467621

  3. Direct, rapid, facile photochemical method for preparing copper nanoparticles and copper patterns.

    PubMed

    Zhu, Xiaoqun; Wang, Bowen; Shi, Feng; Nie, Jun

    2012-10-01

    We develop a facile method for preparing copper nanoparticles and patterned surfaces with copper stripes by ultraviolet (UV) irradiation of a mixture solution containing a photoinitiator and a copper-amine coordination compound. The copper-amine compound is formed by adding diethanol amine to an ethanol solution of copper chloride. Under UV irradiation, free radicals are generated by photoinitiator decomposition. Meanwhile, the copper-amine coordination compound is rapidly reduced to copper particles because the formation of the copper-amine coordination compound prevents the production of insoluble cuprous chloride. Poly(vinylpyrrolidone) is used as a capping agent to prevent the aggregation of the as-prepared copper nanoparticles. The capping agent increases the dispersion of copper nanoparticles in the ethanol solution and affects their size and morphology. Increasing the concentration of the copper-amine coordination compound to 0.1 M directly forms a patterned surface with copper stripes on the transparent substrate. This patterned surface is formed through the combination of the heterogeneous nucleation of copper nanoparticles and photolithography. We also investigate the mechanism of photoreduction by UV-vis spectroscopy and gas chromatography-mass spectrometry. PMID:22974517

  4. Recursive directional ligation by plasmid reconstruction allows rapid and seamless cloning of oligomeric genes.

    PubMed

    McDaniel, Jonathan R; Mackay, J Andrew; Quiroz, Felipe García; Chilkoti, Ashutosh

    2010-04-12

    This paper reports a new strategy, recursive directional ligation by plasmid reconstruction (PRe-RDL), to rapidly clone highly repetitive polypeptides of any sequence and specified length over a large range of molecular weights. In a single cycle of PRe-RDL, two halves of a parent plasmid, each containing a copy of an oligomer, are ligated together, thereby dimerizing the oligomer and reconstituting a functional plasmid. This process is carried out recursively to assemble an oligomeric gene with the desired number of repeats. PRe-RDL has several unique features that stem from the use of type IIs restriction endonucleases: first, PRe-RDL is a seamless cloning method that leaves no extraneous nucleotides at the ligation junction. Because it uses type IIs endonucleases to ligate the two halves of the plasmid, PRe-RDL also addresses the major limitation of RDL in that it abolishes any restriction on the gene sequence that can be oligomerized. The reconstitution of a functional plasmid only upon successful ligation in PRe-RDL also addresses two other limitations of RDL: the significant background from self-ligation of the vector observed in RDL, and the decreased efficiency of ligation due to nonproductive circularization of the insert. PRe-RDL can also be used to assemble genes that encode different sequences in a predetermined order to encode block copolymers or append leader and trailer peptide sequences to the oligomerized gene. PMID:20184309

  5. Rapid Exploration of Configuration Space with Diffusion Map-directed-Molecular Dynamics

    PubMed Central

    Zheng, Wenwei; Rohrdanz, Mary A.; Clementi, Cecilia

    2013-01-01

    The gap between the timescale of interesting behavior in macromolecular systems and that which our computational resources can afford oftentimes limits Molecular Dynamics (MD) from understanding experimental results and predicting what is inaccessible in experiments. In this paper, we introduce a new sampling scheme, named Diffusion Map-directed-MD (DM-d-MD), to rapidly explore molecular configuration space. The method uses diffusion map to guide MD on the fly. DM-d-MD can be combined with other methods to reconstruct the equilibrium free energy, and here we used umbrella sampling as an example. We present results from two systems: alanine dipeptide and alanine-12. In both systems we gain tremendous speedup with respect to standard MD both in exploring the configuration space and reconstructing the equilibrium distribution. In particular, we obtain 3 orders of magnitude of speedup over standard MD in the exploration of the configurational space of alanine-12 at 300K with DM-d-MD. The method is reaction coordinate free and minimally dependent on a priori knowledge of the system. We expect wide applications of DM-d-MD to other macromolecular systems in which equilibrium sampling is not affordable by standard MD. PMID:23865517

  6. Direct Blood Dry LAMP: A Rapid, Stable, and Easy Diagnostic Tool for Human African Trypanosomiasis

    PubMed Central

    Hayashida, Kyoko; Kajino, Kiichi; Hachaambwa, Lottie; Namangala, Boniface; Sugimoto, Chihiro

    2015-01-01

    Loop-mediated isothermal amplification (LAMP) is a rapid and sensitive tool used for the diagnosis of a variety of infectious diseases. One of the advantages of this method over the polymerase chain reaction is that DNA amplification occurs at a constant temperature, usually between 60–65°C; therefore, expensive devices are unnecessary for this step. However, LAMP still requires complicated sample preparation steps and a well-equipped laboratory to produce reliable and reproducible results, which limits its use in resource-poor laboratories in most developing countries. In this study, we made several substantial modifications to the technique to carry out on-site diagnosis of Human African Trypanosomiasis (HAT) in remote areas using LAMP. The first essential improvement was that LAMP reagents were dried and stabilized in a single tube by incorporating trehalose as a cryoprotectant to prolong shelf life at ambient temperature. The second technical improvement was achieved by simplifying the sample preparation step so that DNA or RNA could be amplified directly from detergent-lysed blood samples. With these modifications, diagnosis of HAT in local clinics or villages in endemic areas becomes a reality, which could greatly impact on the application of diagnosis not only for HAT but also for other tropical diseases. PMID:25769046

  7. Directed evolution can rapidly improve the activity of chimeric assembly-line enzymes

    PubMed Central

    Fischbach, Michael A.; Lai, Jonathan R.; Roche, Eric D.; Walsh, Christopher T.; Liu, David R.

    2007-01-01

    Nonribosomal peptides (NRPs) are produced by NRP synthetase (NRPS) enzymes that function as molecular assembly lines. The modular architecture of NRPSs suggests that a domain responsible for activating a building block could be replaced with a domain from a foreign NRPS to create a chimeric assembly line that produces a new variant of a natural NRP. However, such chimeric NRPS modules are often heavily impaired, impeding efforts to create novel NRP variants by swapping domains from different modules or organisms. Here we show that impaired chimeric NRPSs can be functionally restored by directed evolution. Using rounds of mutagenesis coupled with in vivo screens for NRP production, we rapidly isolated variants of two different chimeric NRPSs with ≈10-fold improvements in enzyme activity and product yield, including one that produces new derivatives of the potent NRP/polyketide antibiotic andrimid. Because functional restoration in these examples required only modest library sizes (103 to 104 clones) and three or fewer rounds of screening, our approach may be widely applicable even for NRPSs from genetically challenging hosts. PMID:17620609

  8. Limits of accuracy obtainable in the direct determination by fluorimetry of fluorescent whitening agents in solution.

    PubMed

    Anders, G

    1975-01-01

    In direct determination by fluorimetry the limits of detection are governed by the restricted light stability of fluorescent whitening agents (FWAs) in solution. The initial value of a fluorimetric reading can be registered by a rapid recorder, and in this way very light sensitive traces of FWAs as low as 10 parts per thousand million can be measured be measured with a statistical standard deviation of +/-15% for a single measurement and a reproducibility of +/-50% with a statistical certainty of 99%. PMID:1064529

  9. Rapid and quantitative determination of critical micelle concentration by automatic continuous mixing and static light scattering.

    PubMed

    Paillet, Sabrina; Grassl, Bruno; Desbrières, Jacques

    2009-03-23

    We present the rapid and quantitative characterization of ionic, non-ionic and zwitterionic surfactants based upon the combination of an automatic continuous mixing technique and static light scattering. Collection and subsequent analysis of data are both rapid and semiautomatic, which increases precision, sensitivity, and range of applicability while substantially decreasing the amount of manual intervention required by the investigator. By treating the continuous data, the entire data set may be rapidly analyzed in the context of the closed association model to determine the critical micelle concentration cmc and aggregation number Nag of a detergent; these technique are comparable in the scope and resolution currently obtainable from other conductimetric, fluorescence and surface tension techniques. PMID:19264174

  10. Rapid and simple spectrophotometric determination of persulfate in water by microwave assisted decolorization of Methylene Blue.

    PubMed

    Zhao, Lajuan; Yang, Shiying; Wang, Leilei; Shi, Chao; Huo, Meiqing; Li, Yan

    2015-05-01

    A rapid and simple method for determination of persulfate in aqueous solution was developed. The method is based on the rapid reaction of persulfate with Methylene Blue (MB) via domestic microwave activation, which can promote the activation of persulfate and decolorize MB quickly. The depletion of MB at 644 nm (the maximum absorption wavelength of MB) is in proportion to the increasing concentration of persulfate in aqueous solution. Linear calibration curve was obtained in the range 0-1.5 mmol/L, with a limit of detection of 0.0028 mmol/L. The reaction time is rapid (within 60 sec), which is much shorter than that used for conventional methods. Compared with existing analytical methods, it need not any additives, especially colorful Fe2+, and need not any pretreatment for samples, such as pH adjustment. PMID:25968279

  11. Rapid determination of 226Ra in emergency urine samples

    SciTech Connect

    Maxwell, Sherrod L.; Culligan, Brian K.; Hutchison, Jay B.; Utsey, Robin C.; McAlister, Daniel R.

    2014-02-27

    A new method has been developed at the Savannah River National Laboratory (SRNL) that can be used for the rapid determination of 226Ra in emergency urine samples following a radiological incident. If a radiological dispersive device event or a nuclear accident occurs, there will be an urgent need for rapid analyses of radionuclides in urine samples to ensure the safety of the public. Large numbers of urine samples will have to be analyzed very quickly. This new SRNL method was applied to 100 mL urine aliquots, however this method can be applied to smaller or larger sample aliquots as needed. The method was optimized for rapid turnaround times; urine samples may be prepared for counting in <3 h. A rapid calcium phosphate precipitation method was used to pre-concentrate 226Ra from the urine sample matrix, followed by removal of calcium by cation exchange separation. A stacked elution method using DGA Resin was used to purify the 226Ra during the cation exchange elution step. This approach combines the cation resin elution step with the simultaneous purification of 226Ra with DGA Resin, saving time. 133Ba was used instead of 225Ra as tracer to allow immediate counting; however, 225Ra can still be used as an option. The rapid purification of 226Ra to remove interferences using DGA Resin was compared with a slightly longer Ln Resin approach. A final barium sulfate micro-precipitation step was used with isopropanol present to reduce solubility; producing alpha spectrometry sources with peaks typically <40 keV FWHM (full width half max). This new rapid method is fast, has very high tracer yield (>90 %), and removes interferences effectively. The sample preparation method can also be adapted to ICP-MS measurement of 226Ra, with rapid removal of isobaric interferences.

  12. Direction sensitive laser velocimeter. [determining the direction of particles using a helium-neon laser

    NASA Technical Reports Server (NTRS)

    Franke, J. M. (Inventor)

    1981-01-01

    A laser velocimeter is described which determines the direction of movement of particles. A laser produces a transmitted beam that illuminates the volume under investigation. The backscattered light is divided into two equal intensity beams. A first part of a sample of the transmitted beam is mixed with one of the two equal intensity beams and applied to a first photodetector. A second part of the sample is phase shifted by 90 deg, mixed with the other of the two equal intensity beams and applied to a second photodetector. The output of the first photodetector is phase shifted by 90 deg and then multiplied with the output of the second photodetector to produce a signal indicative of direction of movement.

  13. Rapid Intrinsic Fluorescence Method for Direct Identification of Pathogens in Blood Cultures

    PubMed Central

    Walsh, John D.; Hyman, Jay M.; Borzhemskaya, Larisa; Bowen, Ann; McKellar, Caroline; Ullery, Michael; Mathias, Erin; Ronsick, Christopher; Link, John; Wilson, Mark; Clay, Bradford; Robinson, Ron; Thorpe, Thurman; van Belkum, Alex; Dunne, W. Michael

    2013-01-01

    ABSTRACT A positive blood culture is a critical result that requires prompt identification of the causative agent. This article describes a simple method to identify microorganisms from positive blood culture broth within the time taken to perform a Gram stain (<20 min). The method is based on intrinsic fluorescence spectroscopy (IFS) of whole cells and required development of a selective lysis buffer, aqueous density cushion, optical microcentrifuge tube, and reference database. A total of 1,121 monomicrobial-positive broth samples from 751 strains were analyzed to build a database representing 37 of the most commonly encountered species in bloodstream infections or present as contaminants. A multistage algorithm correctly classified 99.6% of unknown samples to the Gram level, 99.3% to the family level, and 96.5% to the species level. There were no incorrect results given at the Gram or family classification levels, while 0.8% of results were discordant at the species level. In 8/9 incorrect species results, the misidentified isolate was assigned to a species of the same genus. This unique combination of selective lysis, density centrifugation, and IFS can rapidly identify the most common microbial species present in positive blood cultures. Faster identification of the etiologic agent may benefit the clinical management of sepsis. Further evaluation is now warranted to determine the performance of the method using clinical blood culture specimens. PMID:24255123

  14. Direct determination of phosphatase activity from physiological substrates in cells.

    PubMed

    Ren, Zhongyuan; Do, Le Duy; Bechkoff, Géraldine; Mebarek, Saida; Keloglu, Nermin; Ahamada, Saandia; Meena, Saurabh; Magne, David; Pikula, Slawomir; Wu, Yuqing; Buchet, René

    2015-01-01

    A direct and continuous approach to determine simultaneously protein and phosphate concentrations in cells and kinetics of phosphate release from physiological substrates by cells without any labeling has been developed. Among the enzymes having a phosphatase activity, tissue non-specific alkaline phosphatase (TNAP) performs indispensable, multiple functions in humans. It is expressed in numerous tissues with high levels detected in bones, liver and neurons. It is absolutely required for bone mineralization and also necessary for neurotransmitter synthesis. We provided the proof of concept that infrared spectroscopy is a reliable assay to determine a phosphatase activity in the osteoblasts. For the first time, an overall specific phosphatase activity in cells was determined in a single step by measuring simultaneously protein and substrate concentrations. We found specific activities in osteoblast like cells amounting to 116 ± 13 nmol min(-1) mg(-1) for PPi, to 56 ± 11 nmol min(-1) mg(-1) for AMP, to 79 ± 23 nmol min(-1) mg(-1) for beta-glycerophosphate and to 73 ± 15 nmol min(-1) mg(-1) for 1-alpha-D glucose phosphate. The assay was also effective to monitor phosphatase activity in primary osteoblasts and in matrix vesicles. The use of levamisole--a TNAP inhibitor--served to demonstrate that a part of the phosphatase activity originated from this enzyme. An IC50 value of 1.16 ± 0.03 mM was obtained for the inhibition of phosphatase activity of levamisole in osteoblast like cells. The infrared assay could be extended to determine any type of phosphatase activity in other cells. It may serve as a metabolomic tool to monitor an overall phosphatase activity including acid phosphatases or other related enzymes. PMID:25785438

  15. Ultra-rapid earth rotation determination with VLBI during CONT11 and CONT14

    NASA Astrophysics Data System (ADS)

    Haas, Rüdiger; Hobiger, Thomas; Kurihara, Shinobu; Hara, Tetsuya

    2015-08-01

    In 2007 the Geospatial Information Authority of Japan (GSI) and the Onsala Space Observatory (OSO) started a collaboration project aiming at determining the earth rotation angle, usually expressed as UT1-UTC, in near real-time. In the beginning of this project dedicated one hour long one-baseline experiments were observed periodically using the VLBI stations Onsala (Sweden) and Tsukuba (Japan). The strategy is that the observed VLBI data are sent in real-time via the international optical fibre backbone to the correlator at Tsukuba where the data are correlated with a software correlator and analyzed in near-real time with the c5++ VLBI data analysis software, thus producing UT1-UTC results with very low latency. The latency between the observation at the stations and the determination of UT1-UTC is on the order of a few minutes, thus we can talk about an ultra-rapid determination of UT1-UTC. An offline version of this strategy was adopted in 2009 for the regular VLBI intensive series INT-2, organized by the International VLBI Service for Geodesy and Astrometry (IVS), that involves Wettzell (Germany) and Tsukuba. Since March 2010 the INT-2 is using real-time e-transfer, too, and since June 2010 also automated analysis. Starting in 2009 the ultra-rapid approach was applied to regular 24 hour long IVS VLBI-sessions that involve Tsukuba and Onsala, so that ultra-rapid UT1-UTC results can be produced already during ongoing VLBI-sessions. This strategy was successfully operated during the 15 days long continuous VLBI campaigns CONT11 and CONT14. In this presentation we give an overview of the ultra-rapid concept, present the results derived during CONT11 and CONT14, and compare these ultra-rapid results to results derived from post-processing

  16. Ultra-rapid earth rotation determination with VLBI during CONT11 and CONT14

    NASA Astrophysics Data System (ADS)

    Haas, Rüdiger; Hobiger, Thomas; Kurihara, Shinobu; Hara, Tetsuya

    2016-04-01

    In 2007 the Geospatial Information Authority of Japan (GSI) and the Onsala Space Observatory (OSO) started a collaboration project aiming at determining the earth rotation angle, usually expressed as UT1-UTC, in near real-time. In the beginning of this project dedicated one hour long one-baseline experiments were observed periodically using the VLBI stations Onsala (Sweden) and Tsukuba (Japan). The strategy is that the observed VLBI data are sent in real-time via the international optical fibre backbone to the correlator at Tsukuba where the data are correlated with a software correlator and analyzed in near-real time with the c5++ VLBI data analysis software, thus producing UT1-UTC results with very low latency. The latency between the observation at the stations and the determination of UT1-UTC is on the order of a few minutes, thus we can talk about an ultra-rapid determination of UT1-UTC. An offline version of this strategy was adopted in 2009 for the regular VLBI intensive series INT-2, organized by the International VLBI Service for Geodesy and Astrometry (IVS), that involves Wettzell (Germany) and Tsukuba. Since March 2010 the INT-2 is using real-time e-transfer, too, and since June 2010 also automated analysis. Starting in 2009 the ultra-rapid approach was applied to regular 24 hour long IVS VLBI-sessions that involve Tsukuba and Onsala, so that ultra-rapid UT1-UTC results can be produced already during ongoing VLBI-sessions. This strategy was successfully operated during the 15 days long continuous VLBI campaigns CONT11 and CONT14. In this presentation we give an overview of the ultra-rapid concept, present the results derived during CONT11 and CONT14, and compare these ultra-rapid results to results derived from post-processing.

  17. Direct Determination of the Intracellular Oxidation State of Plutonium

    PubMed Central

    Gorman-Lewis, Drew; Aryal, Baikuntha P.; Paunesku, Tatjana; Vogt, Stefan; Lai, Barry; Woloschak, Gayle E.; Jensen, Mark P.

    2013-01-01

    Microprobe X-ray absorption near edge structure (μ-XANES) measurements were used to determine directly, for the first time, the oxidation state of intracellular plutonium in individual 0.1 μm2 areas within single rat pheochromocytoma cells (PC12). The living cells were incubated in vitro for 3 hours in the presence of Pu added to the media in different oxidation states (Pu(III), Pu(IV), and Pu(VI)) and in different chemical forms. Regardless of the initial oxidation state or chemical form of Pu presented to the cells, the XANES spectra of the intracellular Pu deposits was always consistent with tetravalent Pu even though the intracellular milieu is generally reducing. PMID:21755934

  18. Direct determination of the intracellular oxidation state of plutonium.

    PubMed

    Gorman-Lewis, Drew; Aryal, Baikuntha P; Paunesku, Tatjana; Vogt, Stefan; Lai, Barry; Woloschak, Gayle E; Jensen, Mark P

    2011-08-15

    Microprobe X-ray absorption near edge structure (μ-XANES) measurements were used to determine directly, for the first time, the oxidation state of intracellular plutonium in individual 0.1-μm(2) areas within single rat pheochromocytoma cells (PC12). The living cells were incubated in vitro for 3 h in the presence of Pu added to the media in different oxidation states (Pu(III), Pu(IV), and Pu(VI)) and in different chemical forms. Regardless of the initial oxidation state or chemical form of Pu presented to the cells, the XANES spectra of the intracellular Pu deposits were always consistent with tetravalent Pu even though the intracellular milieu is generally reducing. PMID:21755934

  19. Determining Charged Particle Flux Direction in MSL/RAD

    NASA Astrophysics Data System (ADS)

    Appel, J. K.; Kohler, J.; Guo, J.; Ehresmann, B.; Zeitlin, C. J.; Wimmer-Schweingruber, R. F.; Hassler, D.; Rafkin, S. C.; Boehm, E.; Böttcher, S. I.; Martin-Garcia, C.; Brinza, D. E.; Weigle, E.; Lohf, H.; Burmeister, S.; Reitz, G.; Matthiae, D.; Posner, A.; Martín-Torres, J.; Zorzano, M. P.

    2014-12-01

    The Radiation Assessment Detector (RAD) is an instrument onboard the Mars Science Laboratory (MSL) rover Curiosity, currently characterizing the radiation environment on the surface of Mars. The radiation entering the instrument from above consists mostly of Galactic Cosmic Rays (GCRs) modulated by the Martian atmosphere. From below, the instrument is exposed to secondary radiation produced by the interactions of the GCR with the soil. This secondary radiation gets further modulated going through the rover body before entering RAD. We developed a method of determining the direction of the charged particles measured by RAD. This method also extends the energy range possible for measurements with RAD beyond the intruments design limit. Using a combination of GEANT4 and Planetocosmics simulations, we reconstructed the expected charged particle spectra and intensities for upward and downward directed radiation which can be compared with observations. With the developed method, we are able to, for the first time, measure the upward charged particle flux with RAD both during the cruise phase and the surface science phase. Comparing the results of the simulations with the instrument data sets enables us to evaluate the simulation tools used to predict the Martian radiation envronment.

  20. A novel, micro, rapid and direct assay to assess total antioxidant capacity of solid foods.

    PubMed

    Condezo-Hoyos, Luis; Abderrahim, Fatima; Arriba, Silvia M; Carmen González, M

    2015-06-01

    A novel, micro, rapid and direct procedure to measure the total antioxidant capacity of solid foods using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) (mR-QUENCHER-DPPH) was developed and validated. The mR-QUENCHER-DPPH assay was performed in semi-aqueous medium (methanol-Tris buffer) using very small sample amounts (below 3.6 µg), as estimated by a Bradford reagent-based chemical predictor, and it was completed in 10 min at room temperature. The total antioxidant capacity (TAC) of solid foods was expressed as scavenging capacity index (SCI, mmol DPPH scavenged per kg sample), a theoretical and stoichiometric parameter deduced in this study. SCI values measured by mR-QUENCHER-DPPH assay for cereals cous-cous (7.20±0.35), amaranth (7.99±0.35) and buckwheat (194.2±6.72); Goji fruit (91.27±3.98); lotus root (2402±168); and spices turmeric (3767±355), ginger (2493±283), and cinnamon (10461±2133) were further validated using Folin-Ciocalteau assay. Bland-Altman analysis showed that there were not statistically significant differences in TAC values as measured by both assays. In the same way, TAC values measured by mR-QUENCHER-DPPH were correlated with free (r=0.8088, P=0.0151), bound (r=0.9668, P<0.0001) and total (r=0.9067, P=0.0019) reducing capacity of extracts from solid foods as assessed by Folin-Ciocalteau assay. The mR-QUENCHER-DPPH assay allows to measure TAC values using micro-gram amounts in solid food samples with a wide content range of antioxidants (low, high and very high), and omitting the time-consuming dilution cellulose-step commonly employed in the traditional QUENCHER procedures. PMID:25863378

  1. [Rapid determination of silicon content in black liquor of straw fibrous material].

    PubMed

    Li, Hai-Long; Chai, Xin-Sheng; Zhan, Huai-Yu; Liu, Meng-Ru; Fu, Shi-Yu; Sun, Li-Jin

    2012-06-01

    The present paper reports a novel method for the determination of silicon content in straw fibrous material black liquor based on alpha-Si--Mo heteropoly acid spectrophotometry. The selected conditions were as follows: detection wavelength 360 nm, pH 4.0, and reaction time 10 min. It was found that the acidic soluble lignin in the sample liquor was the major interference species in the silicon content determination. The interference of acidic soluble lignin can be eliminated by hydrogen peroxide-nitric acid digestion method. The present method is not only simple, rapid, stable and less interferential, but also of good measurement precision and accuracy, with the relative standard deviations of 0.9%, and recoveries of 99.0%-102%. It is suitable for use in high silicon content of black liquor routine rapid analyses. PMID:22870666

  2. Evaluation of methods for rapid determination of freezing point of aviation fuels

    NASA Technical Reports Server (NTRS)

    Mathiprakasam, B.

    1982-01-01

    Methods for identification of the more promising concepts for the development of a portable instrument to rapidly determine the freezing point of aviation fuels are described. The evaluation process consisted of: (1) collection of information on techniques previously used for the determination of the freezing point, (2) screening and selection of these techniques for further evaluation of their suitability in a portable unit for rapid measurement, and (3) an extensive experimental evaluation of the selected techniques and a final selection of the most promising technique. Test apparatuses employing differential thermal analysis and the change in optical transparency during phase change were evaluated and tested. A technique similar to differential thermal analysis using no reference fuel was investigated. In this method, the freezing point was obtained by digitizing the data and locating the point of inflection. Results obtained using this technique compare well with those obtained elsewhere using different techniques. A conceptual design of a portable instrument incorporating this technique is presented.

  3. Rapid determination of ampicillin in bovine milk by liquid chromatography with fluorescence detection

    SciTech Connect

    Ang, C.Y.W.; Luo, Wenhong

    1997-01-01

    A rapid and sensitive liquid chromatographic (LC) method was developed for the determination of ampicillin residues in raw bovine milk, processed skim milk, and pasteurized, homogenized whole milk with vitamin D. Milk samples were deproteinized with trichloroacetic acid (TCA) and acetonictrile. After centrifugation, the clear supernatant was reacted with formaldehyde and TCA under heat. The major fluorescent derivative of ampicillin was then determined by reversed-phase LC with fluorescence detection. Average recoveries of ampicillin fortified at 5, 10, and 20 ppb (ng/mL) were all >85% with coefficients of variation <10%. Limits of detection ranged from 0.31 to 0.51 ppb and limits of quantitation, from 0.66 to 1.2 ppb. After appropriate validation, this method should be suitable for rapid analysis of milk for ampicillin residues at the tolerance level of 10 ppb. 16 refs., 4 figs., 3 tabs.

  4. Simple XRD algorithm for direct determination of cotton crystallinity

    NASA Astrophysics Data System (ADS)

    Liu, Yongliang; Thibodeaux, Devron; Gamble, Gary; Bauer, Philip; VanDerveer, Don

    2012-06-01

    Traditionally, XRD had been used to study the crystalline structure of cotton celluloses. Despite considerable efforts in developing the curve-fitting protocol to evaluate the crystallinity index (CI), in its present state, XRD measurement can only provide a qualitative or semi-quantitative assessment of the amounts of crystalline and amorphous cellulosic components in a sample. The greatest barrier to establish quantitative XRD is the lack of appropriate cellulose standards needed to calibrate the measurements. In practical, samples with known CIs are very difficult to be prepared or determined. As an approach, we might assign the samples with reported CIs from FT-IR procedure, in which the threeband ratios were first calculated and then were converted into CIs within a large and diversified pool of cotton fibers. This study reports the development of simple XRD algorithm, over time-consuming and subjective curve-fitting process, for direct determination of cotton cellulose CI by correlating XRD with the FT-IR CI references.

  5. [Determination of major carbonyls in mainstream smoke by rapid column high performance liquid chromatography].

    PubMed

    Huang, Yun; Wang, Yigeng; Miao, Mingming; Zhao, Qihua; Yang, Guangyu

    2007-03-01

    Abstract: The determination of major carbonyl compounds in mainstream cigarette smoke by rapid column high performance liquid chromatography was investigated. The cigarette smoke was collected using a Cambridge filter treated with acidic solution of 2, 4-dinitrophenyl-hydrazine. Formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, crotonaldehyde, 2-butanone and butyraldehyde were extracted from the Cambridge filter with 50 mL of 2% pyridine acetonitrile solution. The carbonyl compounds in samples were separated on a ZORBAX Stable Bound rapid column (50 mm x 4. 6 mm, 1. 8 microm) in approximately seven minutes and then determined by high performance liquid chromatography with a diode array detector. The average recoveries were in the range of 89. 1% to 99. 2% and the relative standard deviations (RSDs) were generally below 6. 0%. The eight carbonyl compounds in the mainstream smoke of five brands of cigarettes were determined using this method. This method is faster, simpler and consumes less solvent. It is suitable for rapid analysis of carbonyl compounds in mainstream cigarette smoke. PMID:17580693

  6. Sensitive, Rapid, and Specific Bioassay for the Determination of Antilipogenic Compounds

    PubMed Central

    Ulitzur, S.; Goldberg, I.

    1977-01-01

    A sensitive and rapid bioassay for the determination of the antilipogenic compounds cerulenin and CM-55 is described. The bioassay is based on the inhibitory effect of cerulenin and CM-55 on the in vivo luminescence of an aldehyde-requiring mutant of the marine bacterium Beneckea harveyi. A total quantity as low as 0.1 μg of cerulenin can be determined within 15 min with an error of ±2%. The bioassay, as presented, is specific for compounds that are known to inhibit fatty acid biosynthesis and, as such, it might be used as a general screening method for the detection of antilipogenic compounds. PMID:303076

  7. A rapid ICP-OES strategy for determination of gold and silver in blister copper by nitric acid digestion

    NASA Astrophysics Data System (ADS)

    Zhang, Gai; Tian, Min

    2014-03-01

    A rapid strategy for the analysis of gold and silver in blister copper by inductively coupled plasma optical emission spectrometry (ICP-OES) was firstly proposed. Nitric acid was used to digest blister copper instead of commonly used sulfuric acid. This prevented forming the salt of copper sulfate in the filtration process when the volume of the mixture is very small. Thus, the time of filtration was saved. After filtrating, aqua regia was used to digest the residue and acidize the filter liquor. Two parts of gotten solution were directly determined by ICP-OES. The cycle of analysis was shortened compared with sulfuric acid-fire assay. The proposed method was successfully applied to determine gold and silver in blister copper, and the results were in good agreement with those obtained by lead fire assay.

  8. Development of rapid determination of 18 phthalate esters in edible vegetable oils by gas chromatography tandem mass spectrometry.

    PubMed

    Liu, Yinping; Wang, Shuhui; Wang, Li

    2013-02-13

    A simultaneous and fast determination of 18 phthalic acid esters (PAEs) in edible vegetable oils was developed. After solvent extraction, the PAEs in the oil sample were further cleaned up by solid-phase extraction. After concentration, the extract was directly injected into gas chromatography tandem mass spectrometry (GC-MS/MS) in positive-ion electron impact (EI) mode. Method quantification limits of 18 PAEs were between 0.01 and 0.1 mg/kg. Quantitative recoveries ranging from 63.9 to 115.3% were obtained by analysis of spiked oil. The relative standard deviations were less than 15% (n = 6). The method could potentially overcome the interference from large amounts of lipids and pigment. It was applied to real sample and shown to be a rapid and reliable alternative for determination and confirmation of PAEs in routine analysis. PMID:23339279

  9. Rapid on-line determination of cholesterol distribution among plasma lipoproteins after high-performance gel filtration chromatography.

    PubMed

    Kieft, K A; Bocan, T M; Krause, B R

    1991-05-01

    A high-performance gel chromatography (HPGC) system has been developed which allows the unattended on-line determination of lipoprotein cholesterol distribution (VLDL-C, LDL-C, HDL-C), within 40 min, in microliter quantities of plasma using a single, relatively inexpensive column (Superose 6HR). The FAST cholesterol reagent (Sclavo) and a knitted PFTE Kratos reaction coil (Applied Biosystems) were found to provide optimal sensitivity, linearity, resolution, and dispersion characteristics. Validation is provided by comparison to target values for human quality control reference sera, and by comparing the values obtained by HPGC to the beta-quant method (LRC). The utility of the system is illustrated by comparing profiles from seven different species with normal or elevated plasma cholesterol concentrations. This technique allows rapid analysis of samples, regardless of species, without the use of precipitating agents or the ultracentrifuge. It could also be applied for the direct clinical determination of LDL-cholesterol. PMID:2072044

  10. Evidence for extremely rapid directional changes during the Brunhes-Matuyama polarity transition

    NASA Astrophysics Data System (ADS)

    Sagnotti, L.; Scardia, G.; Giaccio, B.; Liddicoat, J. C.; Nomade, S.; Renne, P. R.; Sprain, C. J.

    2013-12-01

    section, the stratigraphic intervals recording the two RPI minima are each about 50 cm thick (~2.5 ka) and are separated by a ~60 cm thick interval (~3 ka) of higher RPI. During the two RPI minima intervals, sharp directional variations are recorded, showing the occurrence of full Virtual Geomagnetic Pole (VGP) reversals (ca. 180° VGP switch). These polarity switches must have been extremely fast, since essentially no intermediate directions were recorded in individual specimens. We conclude that while the whole period of geomagnetic instability, including the precursor and the final reversal, developed along a time interval of about 8 ka, the associated sharp directional changes were extremely rapid and must have been taken place at a sub-centennial scale.

  11. Direct, non-destructive, and rapid evaluation of developmental cotton fibers by ATR FT-IR spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chemical, compositional, and structural differences within the fibers at different growth stages have been investigated considerably through a number of methodologies. Due to its direct, non-destructive, and rapid attribute, this study reports the utilization of attenuated total reflection Fourier t...

  12. [Rapid site-directed mutagenesis on full-length plasmid DNA by using designed restriction enzyme assisted mutagenesis].

    PubMed

    Zhang, Baozhong; Ran, Duoliang; Zhang, Xin; An, Xiaoping; Shan, Yunzhu; Zhou, Yusen; Tong, Yigang

    2009-02-01

    To use the designed restriction enzyme assisted mutagenesis technique to perform rapid site-directed mutagenesis on double-stranded plasmid DNA. The target amino acid sequence was reversely translated into DNA sequences with degenerate codons, resulting in large amount of silently mutated sequences containing various restriction endonucleases (REs). Certain mutated sequence with an appropriate RE was selected as the target DNA sequence for designing mutation primers. The full-length plasmid DNA was amplified with high-fidelity Phusion DNA polymerase and the amplified product was 5' phosphorylated by T4 polynucleotide kinase and then self-ligated. After transformation into an E. coli host the transformants were rapidly screened by cutting with the designed RE. With this strategy we successfully performed the site-directed mutagenesis on an 8 kb plasmid pcDNA3.1-pIgR and recovered the wild-type amino acid sequence of human polymeric immunoglobulin receptor (pIgR). A novel site-directed mutagenesis strategy based on DREAM was developed which exploited RE as a rapid screening measure. The highly efficient, high-fidelity Phusion DNA polymerase was applied to ensure the efficient and faithful amplification of the full-length sequence of a plasmid of up to 8 kb. This rapid mutagenesis strategy avoids using any commercial site-directed mutagenesis kits, special host strains or isotopes. PMID:19459340

  13. A hybrid approach for rapid, accurate, and direct kilovoltage radiation dose calculations in CT voxel space

    SciTech Connect

    Kouznetsov, Alexei; Tambasco, Mauro

    2011-03-15

    Purpose: To develop and validate a fast and accurate method that uses computed tomography (CT) voxel data to estimate absorbed radiation dose at a point of interest (POI) or series of POIs from a kilovoltage (kV) imaging procedure. Methods: The authors developed an approach that computes absorbed radiation dose at a POI by numerically evaluating the linear Boltzmann transport equation (LBTE) using a combination of deterministic and Monte Carlo (MC) techniques. This hybrid approach accounts for material heterogeneity with a level of accuracy comparable to the general MC algorithms. Also, the dose at a POI is computed within seconds using the Intel Core i7 CPU 920 2.67 GHz quad core architecture, and the calculations are performed using CT voxel data, making it flexible and feasible for clinical applications. To validate the method, the authors constructed and acquired a CT scan of a heterogeneous block phantom consisting of a succession of slab densities: Tissue (1.29 cm), bone (2.42 cm), lung (4.84 cm), bone (1.37 cm), and tissue (4.84 cm). Using the hybrid transport method, the authors computed the absorbed doses at a set of points along the central axis and x direction of the phantom for an isotropic 125 kVp photon spectral point source located along the central axis 92.7 cm above the phantom surface. The accuracy of the results was compared to those computed with MCNP, which was cross-validated with EGSnrc, and served as the benchmark for validation. Results: The error in the depth dose ranged from -1.45% to +1.39% with a mean and standard deviation of -0.12% and 0.66%, respectively. The error in the x profile ranged from -1.3% to +0.9%, with standard deviations of -0.3% and 0.5%, respectively. The number of photons required to achieve these results was 1x10{sup 6}. Conclusions: The voxel-based hybrid method evaluates the LBTE rapidly and accurately to estimate the absorbed x-ray dose at any POI or series of POIs from a kV imaging procedure.

  14. Human Visual Cortex Responses to Rapid Cone and Melanopsin-Directed Flicker

    PubMed Central

    Spitschan, Manuel; Datta, Ritobrato; Stern, Andrew M.

    2016-01-01

    Signals from cones are recombined in postreceptoral channels [luminance, L + M; red-green, L − M; blue-yellow, S − (L + M)]. The melanopsin-containing retinal ganglion cells are also active at daytime light levels and recent psychophysical results suggest that melanopsin contributes to conscious vision in humans. Here, we measured BOLD fMRI responses to spectral modulations that separately targeted the postreceptoral cone channels and melanopsin. Responses to spatially uniform (27.5° field size, central 5° obscured) flicker at 0.5, 1, 2, 4, 8, 16, 32, and 64 Hz were recorded from areas V1, V2/V3, motion-sensitive area MT, and the lateral occipital complex. In V1 and V2/V3, higher temporal sensitivity was observed to L + M + S (16 Hz) compared with L − M flicker (8 Hz), consistent with psychophysical findings. Area MT was most sensitive to rapid (32 Hz) flicker of either L + M + S or L − M. We found S cone responses only in areas V1 and V2/V3 (peak frequency: 4–8 Hz). In addition, we studied an L + M modulation and found responses that were effectively identical at all temporal frequencies to those recorded for the L + M + S modulation. Finally, we measured the cortical response to melanopsin-directed flicker and compared this response with control modulations that addressed stimulus imprecision and the possibility of stimulation of cones in the shadow of retinal blood vessels (penumbral cones). For our stimulus conditions, melanopsin flicker did not elicit a cortical response exceeding that of the control modulations. We note that failure to control for penumbral cone stimulation could be mistaken for a melanopsin response. SIGNIFICANCE STATEMENT The retina contains cone photoreceptors and ganglion cells that contain the photopigment melanopsin. Cones provide brightness and color signals to visual cortex. Melanopsin influences circadian rhythm and the pupil, but its contribution to cortex and perception is less clear. We measured the response of human

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

    DOE PAGESBeta

    Maxwell, Sherrod L.; Culligan, Brian; Hutchison, Jay B.; Utsey, Robin C.; Sudowe, Ralf; McAlister, Daniel R.

    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

  16. Direct determination of absorption anisotropy in colloidal quantum rods

    NASA Astrophysics Data System (ADS)

    Kamal, John Sundar; Gomes, Raquel; Hens, Zeger; Karvar, Masoumeh; Neyts, Kristiaan; Compernolle, Sien; Vanhaecke, Frank

    2012-01-01

    We propose a direct method to determine absorption anisotropy of colloidal quantum rods. In this method, the rods are aligned in solution by using an alternating electric field and we measure simultaneously the resulting average change in absorption. We show that a frequency window for the electric field exists in which the change in absorbance as a function of field strength can be analyzed in terms of the quantum-rod dipole moment and the absorption coefficient for light that is polarized parallel or perpendicular to the long axis of the rod. The approach is verified by measuring the absorbance change of CdSe rods at 400 nm as a function of field strength, where we demonstrate excellent agreement between experiment and theory. This enables us to propose improved values for the CdSe quantum-rod extinction coefficient. Next, we analyze CdSe/CdS dot-in-rods and find that the absorption of the first exciton transition is fully anisotropic, with a vanishing absorption coefficient for light that is polarized perpendicularly to the long axis of the rods.

  17. Direct experimental determination of the atomic structure at internal interfaces

    SciTech Connect

    Browning, N.D. |; Pennycook, S.J.

    1995-07-01

    A crucial first step in understanding the effect that internal interfaces have on the properties of materials is the ability to determine the atomic structure at the interface. As interfaces can contain atomic disorder, dislocations, segregated impurities and interphases, sensitivity to all of these features is essential for complete experimental characterization. By combining Z-contrast imaging and electron energy loss spectroscopy (EELS) in a dedicated scanning transmission electron microscope (STEM), the ability to probe the structure, bonding and composition at interfaces with the necessary atomic resolution has been obtained. Experimental conditions can be controlled to provide, simultaneously, both incoherent imaging and spectroscopy. This enables interface structures observed in the image to be interpreted intuitively and the bonding in a specified atomic column to be probed directly by EELS. The bonding and structure information can then be correlated using bond-valence sum analysis to produce structural models. This technique is demonstrated for 25{degrees}, 36{degrees} and 67{degrees} symmetric and 45{degrees} and 25{degrees} asymmetric [001] tilt grain boundaries in SrTiO{sub 3} The structures of both types of boundary were found to contain partially occupied columns in the boundary plane. From these experimental results, a series of structural units were identified which could be combined, using continuity of gain boundary structure principles, to construct all [001] tilt boundaries in SrTiO{sub 3}. Using these models, the ability of this technique to address the issues of vacancies and dopant segregation at grain boundaries in electroceramics is discussed.

  18. Rapid CMT determination through the joint inversion of GPS and strain data

    NASA Astrophysics Data System (ADS)

    Mencin, D.; Bilham, R. G.; Hodgkinson, K. M.; Mattioli, G. S.

    2013-12-01

    The success of recent efforts to rapidly determine centroid moment tensors of large earthquakes (M>6.5) using geodetic data (Melgar et. al. 2011, Crowell et. al. 2012) has opened up a new area of outreach with the potential to enhance early warning systems and emergency response planning. It would be beneficial to expand these efforts to volcanic activity, but because earthquakes associated with eruptions tend to be smaller, the rapid assessment of centroid moment tensors is limited by noise in the data. Joint inversion of GPS, strainmeter and tiltmeter data potentially provides an enhanced method to determine centroid moments to lower magnitudes. Geodetic instrumentation tends to surround a volcano and hence the inversions care potentially well constrained. We present an algorithm to determine the moment tensors and centroid location of M≈5 earthquakes based on the joint inversions of GPS and borehole strainmeter data. We show that the inversions can be undertaken in near real time. We explore the relative weighting of the data based on instrument characteristics, SNR, event magnitude and distance to achieve optimal inversions and compare the results with seismically determined moment tensors and earthquake location. By simultaneously analyzing data from multiple monitoring systems we will improve our understanding of earthquake characteristics in volcanic settings. Using many different instruments and tools is beneficial in tectonic regions where typically not all types of monitoring systems are available either spatially or temporally due to difficult access, instrument failure or network outages.

  19. A rapid method to determine sterol, erythrodiol, and uvaol concentrations in olive oil.

    PubMed

    Mathison, Brian; Holstege, Dirk

    2013-05-15

    A rapid, accurate, and efficient method for determining the sterol, uvaol, and erythrodiol concentrations was developed to meet International Olive Council (IOC) certification criteria for extra virgin olive oil (EVOO). The unsaponifiable fraction of the sample (0.2 g) was separated with a diatomaceous earth column, and the sterol and triterpenic dialcohols were isolated with a novel base-activated silica solid-phase extraction (SPE) cartridge cleanup protocol. The improved method and the IOC method provided identical pass/fail results (n = 34) for each of the six sterol and erythrodiol/uvaol IOC criteria used to assess olive oil. This method was validated, and recoveries of stigmasterol (88%) and β-sitosterol (84%) were greater than previously published values obtained using the IOC method. This method requires approximately one-third the time required to complete the IOC method and has great utility for the rapid screening of EVOO to detect adulteration, false labeling, and an inferior product. PMID:23587059

  20. Fuji apple storage time rapid determination method using Vis/NIR spectroscopy.

    PubMed

    Liu, Fuqi; Tang, Xuxiang

    2015-01-01

    Fuji apple storage time rapid determination method using visible/near-infrared (Vis/NIR) spectroscopy was studied in this paper. Vis/NIR diffuse reflection spectroscopy responses to samples were measured for 6 days. Spectroscopy data were processed by stochastic resonance (SR). Principal component analysis (PCA) was utilized to analyze original spectroscopy data and SNR eigen value. Results demonstrated that PCA could not totally discriminate Fuji apples using original spectroscopy data. Signal-to-noise ratio (SNR) spectrum clearly classified all apple samples. PCA using SNR spectrum successfully discriminated apple samples. Therefore, Vis/NIR spectroscopy was effective for Fuji apple storage time rapid discrimination. The proposed method is also promising in condition safety control and management for food and environmental laboratories. PMID:25874818

  1. A preliminary report on the rapid fluorimetric determination of uranium in low-grade ores

    USGS Publications Warehouse

    Grimaldi, F.S.; Levine, Harry

    1950-01-01

    A simple and very rapid fluorimetric procedure is described for the determination of uranium in low-grade shale and phosphate ores. The best working range is from 0.001 to about 0.04 percent U. The procedure employs batch extraction of uranium nitrate by ethyl acetate, using aluminum nitrate as the salting agent, prior to the visual fluorimetric estimation. The procedure is especially designed to save reagents; only 9.5 g of aluminum nitrate and 10 ml of ethyl acetate being used for one analysis. The solution of the sample by means of a fusion with NaOH-NaNO3 flux is rapid. After fusion the sample is immediately extracted without removing silica and other hydrolytic precipitates. Aluminum nitrate very effectively ties up fluoride and phosphate, thus eliminating steps required for their removal.

  2. Rapid HPLC-MS method for the simultaneous determination of tea catechins and folates.

    PubMed

    Araya-Farias, Monica; Gaudreau, Alain; Rozoy, Elodie; Bazinet, Laurent

    2014-05-14

    An effective and rapid HPLC-MS method for the simultaneous separation of the eight most abundant tea catechins, gallic acid, and caffeine was developed. These compounds were rapidly separated within 9 min by a linear gradient elution using a Zorbax SB-C18 packed with sub 2 μm particles. This methodology did not require preparative and semipreparative HPLC steps. In fact, diluted tea samples can be easily analyzed using HPLC-MS as described in this study. The use of mass spectrometry detection for quantification of catechins ensured a higher specificity of the method. The percent relative standard deviation was generally lower than 4 and 7% for most of the compounds tested in tea drinks and tea extracts, respectively. Furthermore, the method provided excellent resolution for folate determination alone or in combination with catechins. To date, no HPLC method able to discriminate catechins and folates in a quick analysis has been reported in the literature. PMID:24734959

  3. A Design Methodology for Rapid Implementation of Active Control Systems Across Lean Direct Injection Combustor Platforms

    NASA Technical Reports Server (NTRS)

    Baumann, William T.; Saunders, William R.; Vandsburger, Uri; Saus, Joseph (Technical Monitor)

    2003-01-01

    The VACCG team is comprised of engineers at Virginia Tech who specialize in the subject areas of combustion physics, chemical kinetics, dynamics and controls, and signal processing. Currently, the team's work on this NRA research grant is designed to determine key factors that influence combustion control performance through a blend of theoretical and experimental investigations targeting design and demonstration of active control for three different combustors. To validiate the accuracy of conclusions about control effectiveness, a sequence of experimental verifications on increasingly complex lean, direct injection combustors is underway. During the work period January 1, 2002 through October 15, 2002, work has focused on two different laboratory-scale combustors that allow access for a wide variety of measurements. As the grant work proceeds, one key goal will be to obtain certain knowledge about a particular combustor process using a minimum of sophisticated measurements, due to the practical limitations of measurements on full-scale combustors. In the second year, results obtained in the first year will be validated on test combustors to be identified in the first quarter of that year. In the third year, it is proposed to validate the results at more realistic pressure and power levels by utilizing the facilities at the Glenn Research Center.

  4. Determination of backbone chain direction of PDA using FFM

    NASA Astrophysics Data System (ADS)

    Jo, Sadaharu; Okamoto, Kentaro; Takenaga, Mitsuru

    2010-01-01

    The effect of backbone chains on friction force was investigated on both Langmuir-Blodgett (LB) films of 10,12-heptacosadiynoic acid and the (0 1 0) surfaces of single crystals of 2,4-hexadiene-1,6-diol using friction force microscopy (FFM). It was observed that friction force decreased when the scanning direction was parallel to the [0 0 1] direction in both samples. Moreover, friction force decreased when the scanning direction was parallel to the crystallographic [1 0 2], [1 0 1], [1 0 0] and [1 0 1¯] directions in only the single crystals. For the LB films, the [0 0 1] direction corresponds to the backbone chain direction of 10,12-heptacosadiynoic acid. For the single crystals, both the [0 0 1] and [1 0 1] directions correspond to the backbone chain direction, and the [1 0 2], [1 0 0] and [1 0 1¯] directions correspond to the low-index crystallographic direction. In both the LB films and single crystals, the friction force was minimized when the directions of scanning and the backbone chain were parallel.

  5. Simultaneous and rapid determination of multiple component concentrations in a Kraft liquor process stream

    SciTech Connect

    Li, Jian; Chai, Xin Sheng; Zhu, Junyoung

    2008-06-24

    The present invention is a rapid method of determining the concentration of the major components in a chemical stream. The present invention is also a simple, low cost, device of determining the in-situ concentration of the major components in a chemical stream. In particular, the present invention provides a useful method for simultaneously determining the concentrations of sodium hydroxide, sodium sulfide and sodium carbonate in aqueous kraft pulping liquors through use of an attenuated total reflectance (ATR) tunnel flow cell or optical probe capable of producing a ultraviolet absorbency spectrum over a wavelength of 190 to 300 nm. In addition, the present invention eliminates the need for manual sampling and dilution previously required to generate analyzable samples. The inventive method can be used in Kraft pulping operations to control white liquor causticizing efficiency, sulfate reduction efficiency in green liquor, oxidation efficiency for oxidized white liquor and the active and effective alkali charge to kraft pulping operations.

  6. Rapid Detection of Microorganisms--State of Art and Future Directions

    NASA Astrophysics Data System (ADS)

    Hong, George

    2008-03-01

    For the last several decades, nutrient-based culture growth methods have been accepted as the standard for microorganism detection and identification. However, since the discovery of nucleic acids and molecular breakthrough technologies such as restriction enzymes and polymerase chain reactions, the detection and identification of microorganisms have advanced to culture-independent methods that fall under the category of rapid microbial detections. Here, we present an overview of major rapid microbial detection technologies. These technologies will include both amplification and non-amplification based methods for the detection and identification of target microorganisms. The technologies described can be applied to detecting a wide variety of microorganisms, including bacteria, viruses, mycoplasma, and fungi and have the potential sensitivity to detect a single microorganism. Also in this presentation, we will present examples of real-life applications as well as future challenges for the advancement of the field of rapid microbiology.

  7. Rapid Procedure for Determining Present Plate Motion at Any Point on the Earth's Surface.

    ERIC Educational Resources Information Center

    Christofferson, Eric

    1986-01-01

    Presents a procedure for calculating the compass direction and velocity of present plate motions at any geographical point of interest. Includes a table of the relative and geographic motion of the 11 largest plates and a flow chart for determining their present motion. Also offers suggestions for classroom instruction. (ML)

  8. Sex Differences in Knee Flexion Angle During a Rapid Change of Direction While Running

    PubMed Central

    Sheu, Christopher L.; Gray, Aaron M.; Brown, David; Smith, Brian A.

    2015-01-01

    Background: Females experience greater overall rates of athletic anterior cruciate ligament (ACL) injury than males. The specific mechanisms of the predisposition remain unclear. Hypothesis: Modeling of knee kinematics has shown that the more extended the knee joint, the greater the strain on the ACL. The authors hypothesized that female athletes would have a lesser degree of knee flexion than male athletes at initial ground contact while performing change-of-direction cutting maneuvers. Study Design: Controlled laboratory study. Methods: Twenty female and 20 male high school soccer athletes with at least 1 year of experience were recruited for the study. Athletes were excluded if they had a history of any major lower limb injury or current knee pain causing a reduction in training and/or competition. Reflective markers were attached at the greater trochanter of the femur, the lateral epicondyle of the knee, and the lateral malleolus of the ankle to enable motion capture. Each athlete performed 6 change-of-direction maneuvers in random order in front of 2 cameras. Multiple regression analysis was used to determine differences between the sexes from the motion data captured; P < .05 defined significance. Results: Statistically significant differences existed in knee flexion angles between male and female participants at the 90° and 135° cutting angles. At 90°, males and females showed initial contact knee flexion angles (mean ± SD) of 39.0° ± 6.8° and 29.3° ± 6.2°, respectively (P < .0001), and mean maximum flexion angles of 56.4° ± 6.9° and 49.7° ± 7.0°, respectively (P = .0036). At 135°, males and females showed mean initial contact knee flexion angles of 36.8° ± 7.9° and 29.7° ± 7.8°, respectively (P = .0053), and mean maximum flexion angles of 60.7° ± 8.1° and 51.6° ± 9.4°, respectively (P = .0017). Conclusion: The research conducted is intended to foster an awareness of injury disposition in female athletes and guide future

  9. [Rapid determination of componential contents and calorific value of selected agricultural biomass feedstocks using spectroscopic technology].

    PubMed

    Sheng, Kui-Chuan; Shen, Ying-Ying; Yang, Hai-Qing; Wang, Wen-Jin; Luo, Wei-Qiang

    2012-10-01

    Rapid determination of biomass feedstock properties is of value for the production of biomass densification briquetting fuel with high quality. In the present study, visible and near-infrared (Vis-NIR) spectroscopy was employed to build prediction models of componential contents, i. e. moisture, ash, volatile matter and fixed-carbon, and calorific value of three selected species of agricultural biomass feedstock, i. e. pine wood, cedar wood, and cotton stalk. The partial least squares (PLS) cross validation results showed that compared with original reflection spectra, PLS regression models developed for first derivative spectra produced higher prediction accuracy with coefficients of determination (R2) of 0.97, 0.94 and 0.90, and residual prediction deviation (RPD) of 6.57, 4.00 and 3.01 for ash, volatile matter and moisture, respectively. Good prediction accuracy was achieved with R2 of 0.85 and RPD of 2.55 for fixed carbon, and R2 of 0.87 and RPD of 2.73 for calorific value. It is concluded that the Vis-NIR spectroscopy is promising as an alternative of traditional proximate analysis for rapid determination of componential contents and calorific value of agricultural biomass feedstock PMID:23285891

  10. Rapid determination of internal volumes of membrane vesicles with electron spin resonance-stopped flow technique.

    PubMed

    Anzai, K; Higashi, K; Kirino, Y

    1988-01-13

    We have developed an electron spin resonance (ESR)-stopped flow technique and employed it for the simple and rapid determination of internal volumes of biomembrane vesicles and liposomes. A vesicle suspension containing a neutral and membrane-permeable spin label, 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (TEMPONE), was mixed in the stopped-flow apparatus with an isotonic solution of relatively impermeable line broadening agents, potassium tris(oxalato)chromate(III) or potassium ferricyanide, and an ESR spectrum was recorded. From the relative intensity of the sharp triplet signal due to TEMPONE in the aqueous space within vesicles, the determination of the internal aqueous volume was straightforward. Using this technique, it is possible to measure intravesicular volumes in 0.1 s. The internal volume of sonicated phospholipid vesicles was approximately 0.3 microliter/mg lipid. The light fraction of sarcoplasmic reticulum membrane vesicles isolated from rabbit skeletal muscle was estimated to have an internal volume of 2.2-2.6 microliter/mg protein in its resting state. Activation of Ca2+ pumps in the membrane upon addition of ATP and Ca2+ ions decreased the internal volume by about 10%. This finding supports the hypothesis that the Ca2+ pump is electrogenic and that the efflux of potassium ions compensates for the influx of positive charges. The present technique is widely applicable to the simple and rapid determination of the internal volumes of membrane vesicles. PMID:2825810

  11. Determinants of the electric field during transcranial direct current stimulation.

    PubMed

    Opitz, Alexander; Paulus, Walter; Will, Susanne; Antunes, Andre; Thielscher, Axel

    2015-04-01

    Transcranial direct current stimulation (tDCS) causes a complex spatial distribution of the electric current flow in the head which hampers the accurate localization of the stimulated brain areas. In this study we show how various anatomical features systematically shape the electric field distribution in the brain during tDCS. We constructed anatomically realistic finite element (FEM) models of two individual heads including conductivity anisotropy and different skull layers. We simulated a widely employed electrode montage to induce motor cortex plasticity and moved the stimulating electrode over the motor cortex in small steps to examine the resulting changes of the electric field distribution in the underlying cortex. We examined the effect of skull thickness and composition on the passing currents showing that thinner skull regions lead to higher electric field strengths. This effect is counteracted by a larger proportion of higher conducting spongy bone in thicker regions leading to a more homogenous current over the skull. Using a multiple regression model we could identify key factors that determine the field distribution to a significant extent, namely the thicknesses of the cerebrospinal fluid and the skull, the gyral depth and the distance to the anode and cathode. These factors account for up to 50% of the spatial variation of the electric field strength. Further, we demonstrate that individual anatomical factors can lead to stimulation "hotspots" which are partly resistant to electrode positioning. Our results give valuable novel insights in the biophysical foundation of tDCS and highlight the importance to account for individual anatomical factors when choosing an electrode montage. PMID:25613437

  12. Rapid method for the determination of 226Ra in hydraulic fracturing wastewater samples

    DOE PAGESBeta

    Maxwell, Sherrod L.; Culligan, Brian K.; Warren, Richard A.; McAlister, Daniel R.

    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.

  13. Directional Effects between Rapid Auditory Processing and Phonological Awareness in Children

    ERIC Educational Resources Information Center

    Johnson, Erin Phinney; Pennington, Bruce F.; Lee, Nancy Raitano; Boada, Richard

    2009-01-01

    Background: Deficient rapid auditory processing (RAP) has been associated with early language impairment and dyslexia. Using an auditory masking paradigm, children with language disabilities perform selectively worse than controls at detecting a tone in a backward masking (BM) condition (tone followed by white noise) compared to a forward masking…

  14. Rapid genotypic detection of rifampin- and isoniazid-resistant Mycobacterium tuberculosis directly in clinical specimens.

    PubMed

    Bang, Didi; Bengård Andersen, Ase; Thomsen, Vibeke Østergaard

    2006-07-01

    A multiplex PCR DNA strip assay (Genotype MTBDR) designed to detect rifampin (rpoB) and high-level isoniazid (katG) resistance mutations in Mycobacterium tuberculosis isolates was optimized for clinical specimens. Successful genotypic results were achieved with 36 of 38 (95%) smear-positive respiratory specimens, allowing rapid therapeutic adjustments in transmittable drug-resistant tuberculosis. PMID:16825393

  15. Rapid reversed-phase liquid chromatographic determination of patulin in apple juice.

    PubMed

    Gökmen, V; Acar, J

    1996-04-12

    A rapid, simple and economical method using a limited amount of organic solvent is described for the determination of patulin in apple juice. The sample was extracted with ethyl acetate and the extract was cleaned up by extraction with sodium carbonate solution. Patulin was then determined by reversed-phase liquid chromatography using a MicroPack C18 column and a variable-wavelength UV-Vis detector set at 276 nm. Patulin and 5-hydroxymethylfurfural were completely resolved by using water-acetonitrile (99:1, v/v) as the mobile phase at a flow-rate of 1.0 ml/min. The detection limit was < 5 micrograms/l and the recovery was 98%. PMID:8680596

  16. Limits of rapid log P determination methods for highly lipophilic and flexible compounds.

    PubMed

    Martel, Sophie; Begnaud, Frédéric; Schuler, William; Gillerat, Fabrice; Oberhauser, Nils; Nurisso, Alessandra; Carrupt, Pierre-Alain

    2016-04-01

    Lipophilicity is of crucial importance in many fields including pharmaceutical, environmental, cosmetic and food industries. Whereas different experimental strategies have been developed for rapid lipophilicity determination of new chemical entities, log P determination of highly lipophilic compounds is always challenging. In this study, three published chromatographic methods have been compared on a series of phenylalkanoic acids including the pro-perfume HaloscentD (HD-C12). Different log P values were obtained depending on the chromatographic method used for log P estimation. Molecular modelling suggested that log P variations may be due to the chromatographic conditions applied (isocratic or gradient mode, ratio methanol/water in the mobile phase), responsible of specific conformations of the molecule in solution. Thus, for flexible compounds, published methods have to be used with caution and considered as a good tool to estimate a log P range, depending on the molecular conformational state. PMID:26995644

  17. Rapid determination of hydrogen peroxide in pulp bleaching effluents by headspace gas chromatography.

    PubMed

    Hu, Hui-Chao; Jin, Hui-Jun; Chai, Xin-Sheng

    2012-04-27

    A headspace gas chromatographic (HS-GC) method has been developed for the determination of residual hydrogen peroxide in pulp bleaching effluents. The method is based on the reaction of hydrogen peroxide and permanganate in an acidic medium (0.1 mol/L), in which hydrogen peroxide is quantitatively converted to oxygen within 10 min at 60°C in a sealed headspace sample vial. The released oxygen is then determined by GC equipped with a thermal conductivity detector. The method is robust, sensitive, and accurate, with reproducibility characterized by a relative standard deviation of <0.5%, a sensitivity whose limit of quantification (LOQ) is 0.96 μmol, and a demonstrated recovery ranging from 98 to 103%. Further, the method is simple, rapid, and automated. PMID:22444430

  18. Rapid endoglin determination in serum samples using an amperometric magneto-actuated disposable immunosensing platform.

    PubMed

    Torrente-Rodríguez, Rebeca M; Campuzano, Susana; Ruiz-Valdepeñas-Montiel, Víctor; Pedrero, María; Fernández-Aceñero, M Jesús; Barderas, Rodrigo; Pingarrón, José M

    2016-09-10

    A sensitive and rapid method for the determination of the clinically relevant biomarker human endoglin (CD105) in serum samples is presented, involving a magneto-actuated immunoassay and amperometric detection at disposable screen-printed carbon electrodes (SPCEs). Micro-sized magnetic particles were modified with a specific antibody to selectively capture the target protein which was further sandwiched with a secondary HRP-labeled antibody. The immunocomplexes attached to the magnetic carriers were amperometrically detected at SPCEs using the hydroquinone (HQ)/H2O2/HRP system. The magneto-actuated immunosensing platform was able to detect 5 pmoles of endoglin (in 25μL of sample, 0.2μM) in 30min providing statistically similar results to those obtained using a commercial ELISA kit for the determination of endogenous content of endoglin in human serum samples. PMID:27448312

  19. Rapid determination of moisture content in paper materials by multiple headspace extraction gas chromatography.

    PubMed

    Xie, Wei-Qi; Chai, Xin-Sheng

    2016-04-22

    This paper describes a new method for the rapid determination of the moisture content in paper materials. The method is based on multiple headspace extraction gas chromatography (MHE-GC) at a temperature above the boiling point of water, from which an integrated water loss from the tested sample due to evaporation can be measured and from which the moisture content in the sample can be determined. The results show that the new method has a good precision (with the relative standard deviation <0.96%), high sensitivity (the limit of quantitation=0.005%) and good accuracy (the relative differences <1.4%). Therefore, the method is quite suitable for many uses in research and industrial applications. PMID:27033986

  20. Rapid acid digestion and simple microplate method for milk iodine determination.

    PubMed

    Hedayati, Mehdi; Ordookhani, Arash; Daneshpour, Maryam Sadat; Azizi, Fereidoun

    2007-01-01

    Iodine deficiency leads to deficiency of thyroid hormones, which causes mental retardation in infant. Laboratory confirmation is important in its diagnosis. The major problems associated with the existing methods for iodine determination in milk samples are: 1) nonsafe alkaline solution; 2) harsh thermal condition; and 3) extra time required to complete various steps. In this study, a simple and rapid colorimetric method was investigated, which used acid digestion in combination with a rapid microplate reading format method to determine the total iodine content in milk. Sample digestion was done on 50 microL milk in metavanadate/perchloric, at 230 degrees C for 10 min. After digestion, iodine determination was based on the Sandell-Kolthoff reaction. The reaction results were read in 96-well microplates by an enzyme-linked immunosorbent assay (ELISA) reader. The determination range of the assay was between 2 and 40 microg/dL. The within-run coefficient of variation percent in three levels (3, 12, and 36 microg/dL) ranged from 6.7 to 9.3 and between-run coefficients of variation ranged from 8.6 to 12.3%. The results obtained (n=70) by the optimized method have good correlation with the results of alkaline incineration as a reference method (n=70; r2=0.907; y=0.952x+1.77). Recovery tests for accuracy assessment in six levels from 6.2 to 34.2 microg/dL) were between 91.3 and 113%. This method has enabled us to achieve 0.12 microg/dL sensitivity. The results of this study show that a quick acid digestion combined with mild thermal and low sample volume with a quick reading of assay results were the main advantages of the acid digestion and microplate reading format. PMID:17847102

  1. Rapid fabrication and packaging of AlGaN/GaN high-temperature ultraviolet photodetectors using direct wire bonding

    NASA Astrophysics Data System (ADS)

    So, Hongyun; Senesky, Debbie G.

    2016-07-01

    Cost-effective fabrication and rapid packaging of AlGaN/GaN ultraviolet (UV) photodetectors was demonstrated using direct wire bonding between aluminum wires and a GaN surface. The fabricated photodetectors showed stable dark current levels through the highly conductive 2D electron gas (2DEG), which was electrically connected to aluminum bonding wires. At room temperature, the current passing through the 2DEG rapidly increased upon exposure to UV light because of the generated electrons excited in the AlGaN/GaN layers. In addition, the devices showed consistent and reliable operation at high temperatures up to 100 °C with mechanically stable bonding wires (pull strength of 3–5.2 gram-force), supporting the use of direct wire bonding techniques to fabricate simple AlGaN/GaN sensors for UV detection within harsh environments, such as downhole and space exploration applications.

  2. Formation of stable nanocarriers by in situ ion pairing during block-copolymer-directed rapid precipitation.

    PubMed

    Pinkerton, Nathalie M; Grandeury, Arnaud; Fisch, Andreas; Brozio, Jörg; Riebesehl, Bernd U; Prud'homme, Robert K

    2013-01-01

    We present an in situ hydrophobic salt forming technique for the encapsulation of weakly hydrophobic, ionizable active pharmaceutical ingredients (API) into stable nanocarriers (NCs) formed via a rapid precipitation process. Traditionally, NC formation via rapid precipitation has been difficult with APIs in this class because their intermediate solubility makes achieving high supersaturation difficult during the precipitation process and the intermediate solubility causes rapid Ostwald ripening or recrystallization after precipitation. By forming a hydrophobic salt in situ, the API solubility and crystallinity can be tuned to allow for NC formation. Unlike covalent API modification, the hydrophobic salt formation modifies properties via ionic interactions, thus circumventing the need for full FDA reapproval. This technique greatly expands the types of APIs that can be successfully encapsulated in NC form. Three model APIs were investigated and successfully incorporated into NCs by forming salts with hydrophobic counterions: cinnarizine, an antihistamine, clozapine, an antipsychotic, and α-lipoic acid, a common food supplement. We focus on cinnarizine to develop the rules for the in situ nanoprecipitation of salt NCs. These rules include the pK(a)s and solubilities of the API and counterion, the effect of the salt former-to-API ratio on particle stability and encapsulation efficiency, and the control of NC size. Finally, we present results on the release rates of these ion pair APIs from the NCs. PMID:23259920

  3. The ultra-rapid synthesis of 2D graphitic carbon nitride nanosheets via direct microwave heating for field emission.

    PubMed

    Yu, Yongzhi; Zhou, Qing; Wang, Jigang

    2016-02-16

    The 2D g-C3N4 nanosheets were ultra-rapidly prepared via a direct microwave heating approach. The as-synthesized g-C3N4 possessed a large surface area, few stacking layers, a large aspect ratio and an enlarged bandgap. As a consequence, the excellent field emission properties of 2D g-C3N4 nanosheets were exhibited with extremely low turn-on fields. PMID:26879135

  4. Direct Determinations of the πNN Coupling Constants

    NASA Astrophysics Data System (ADS)

    Ericson, T. E. O.; Loiseau, B.

    1998-11-01

    A novel extrapolation method has been used to deduce directly the charged πN N coupling constant from backward np differential scattering cross sections. The extracted value, g2c = 14.52(0.26) is higher than the indirectly deduced values obtained in nucleon-nucleon energy-dependent partial-wave analyses. Our preliminary direct value from a reanalysis of the GMO sum-rule points to an intermediate value of g2c about 13.97(30).

  5. Direct methods for the determination of lead in whole blood by anodic stripping voltammetry.

    PubMed

    Lee, S W; Méranger, J C

    1980-12-01

    Two methods for the direct determination of lead in whole blood by anodic stripping voltammetry (ASV) are described. The procedure in both methods involved the mixing of micro blood samples with a metal releasing reagent, Metexchange, and electrochemical analysis using carbon electrodes. A multiple Anodic Stripping Analyzer equipped with composite graphite mercury electrodes and a Charge Transfer Analyzer equipped with a mercury film electrode were employed. The standard addition method was used to minimize the matrix effects of whole blood. The ASV results correlated well with those obtained by flameless atomic absorption analysis. The methods are simple, reliable, and suitable for applications in the clinical field. The procedure using the Charge Transfer Analyzer is recommended because of its sensitivity and rapidity. PMID:7211939

  6. Commercialized rapid immunoanalytical tests for determination of allergenic food proteins: an overview.

    PubMed

    Schubert-Ullrich, Patricia; Rudolf, Judith; Ansari, Parisa; Galler, Brigitte; Führer, Manuela; Molinelli, Alexandra; Baumgartner, Sabine

    2009-09-01

    Food allergies have become an important health issue especially in industrialized countries. Undeclared allergenic ingredients or the presence of "hidden" allergens because of contamination during the food production process pose great health risks to sensitised individuals. The EU directive for food labelling lists allergenic foods that have to be declared on food products by the manufacturers. The list includes gluten-containing cereals, crustaceans, eggs, fish, peanuts, soybeans, milk, various nuts (e.g. almond, hazelnut, and walnut, etc.), celery, mustard, sesame seeds, lupin, and molluscs. Reliable methods for detection and quantification of food allergens are needed that can be applied in a fast and easy-to-use manner, are portable, and need only limited technical equipment. This review focuses on the latest developments in food allergen analysis with special emphasis on fast immunoanalytical methods such as rapid enzyme-linked immunosorbent assays (ELISA), lateral-flow immunochromatographic assays (LFA) and dipstick tests. Emerging technologies such as immunochemical microarrays and biosensors are also discussed and their application to food allergen analysis is reviewed. Finally, a comprehensive overview of rapid immunochemical test kits that are currently available commercially is given in tabular form. PMID:19308361

  7. Combining nebulization-mediated transfection and polymer microarrays for the rapid determination of optimal transfection substrates.

    PubMed

    Unciti-Broceta, Asier; Díaz-Mochón, Juan J; Mizomoto, Hitoshi; Bradley, Mark

    2008-01-01

    In this manuscript, we report how transfection efficiencies vary as a function of the substrate upon which cells adhere using a polymer microarray platform to allow rapid analysis of a large number of substrates. During these studies, traditional transfection protocols were nonsatisfactory, and thus we developed an approach in which an ultrasonic nebulizer was used to dispense lipoplexes onto cell-based microarrays in the absence of liquid. Under these conditions, droplets were directly deposited onto the cells thereby enhancing transfection. This approach was successfully applied to the transfection of various cell lines immobilized on a library of polyacrylates and permitted the identification of highly efficient transfection/polymer combinations, while showing that specific polymer-cell interactions may promote the efficacy of chemical transfection. PMID:18247582

  8. Rapid and accurate determination of the lignin content of lignocellulosic biomass by solid-state NMR

    PubMed Central

    Fu, Li; McCallum, Scott A.; Miao, Jianjun; Hart, Courtney; Tudryn, Gregory J.; Zhang, Fuming; Linhardt, Robert J.

    2014-01-01

    Biofuels and biomaterials, produced from lignocellulosic feedstock, require facile access to cellulose and hemicellulose to be competitive with petroleum processing and sugar-based fermentation. Physical-chemical barriers resulting from lignin complicates the hydrolysis biomass into fermentable sugars. Thus, the amount of lignin within a substrate is critical in determining biomass processing. The application of 13C cross-polarization, magic-angle spinning, and solid-state nuclear magnetic resonance for the direct quantification of lignin content in biomass is examined. Using a standard curve constructed from pristine lignin and cellulose, the lignin content of a biomass sample is accurately determined through direct measurement without chemical or enzymatic pre-treatment. PMID:25404762

  9. Rapid and accurate determination of the lignin content of lignocellulosic biomass by solid-state NMR.

    PubMed

    Fu, Li; McCallum, Scott A; Miao, Jianjun; Hart, Courtney; Tudryn, Gregory J; Zhang, Fuming; Linhardt, Robert J

    2015-02-01

    Biofuels and biomaterials, produced from lignocellulosic feedstock, require facile access to cellulose and hemicellulose to be competitive with petroleum processing and sugar-based fermentation. Physical-chemical barriers resulting from lignin complicates the hydrolysis biomass into fermentable sugars. Thus, the amount of lignin within a substrate is critical in determining biomass processing. The application of (13)C cross-polarization, magic-angle spinning, and solid-state nuclear magnetic resonance for the direct quantification of lignin content in biomass is examined. Using a standard curve constructed from pristine lignin and cellulose, the lignin content of a biomass sample is accurately determined through direct measurement without chemical or enzymatic pre-treatment. PMID:25404762

  10. Lunar soft landing rapid trajectory optimization using direct collocation method and nonlinear programming

    NASA Astrophysics Data System (ADS)

    Tu, Lianghui; Yuan, Jianping; Luo, Jianjun; Ning, Xin; Zhou, Ruiwu

    2007-11-01

    Direct collocation method has been widely used for trajectory optimization. In this paper, the application of direct optimization method (direct collocation method & nonlinear programming (NLP)) to lunar probe soft-landing trajectory optimization is introduced. Firstly, the model of trajectory optimization control problem to lunar probe soft landing trajectory is established and the equations of motion are simplified respectively based on some reasonable hypotheses. Performance is selected to minimize the fuel consumption. The control variables are thrust attack angle and thrust of engine. Terminal state variable constraints are velocity and altitude constraints. Then, the optimal control problem is transformed into nonlinear programming problem using direct collocation method. The state variables and control variables are selected as optimal parameters at all nodes and collocation nodes. Parameter optimization problem is solved using the SNOPT software package. The simulation results demonstrate that the direct collocation method is not sensitive to lunar soft landing initial conditions; they also show that the optimal solutions of trajectory optimization problem are fairly good in real-time. Therefore, the direct collocation method is a viable approach to lunar probe soft landing trajectory optimization problem.

  11. Method of rapid determination of MHD equilibrium properties with the modified version of the SURFAS code

    SciTech Connect

    Lee, D.K.; Hirshman, S.P.; Okabayashi, M.; Reusch, M.F.; Sun, Y.C.

    1993-09-01

    Rapid determination of MHD eqilibrium properties of tokamak plasmas is carried out by means of an approximation method based on the use of database files. These are computed a priori from MHD equilibrium solutions obtained by performing reconstruction to match experimental measurements, which include motional Stark effect (MSE) data. The procedure carries out a single iteration of Newton`s method to determine the poloidal variation of the toroidal plasma current density in the equilibrium form j{sub {phi}} = {minus}2{pi}({mu}{sub 0}Rp{prime} + FF{prime}/R) by representing p{prime}({psi}) and F({psi})F{prime}({psi}) in series expansions of Chebyshev polynomials. The polynominal expansion coefficients are obtained through a least-squares data fitting process similar to that used in the equilibrium reconstruction. Knowing the current density j{phi} allows the determination of the internal q-profile from the MSE data. This important stability parameter is generally unavailable from a current filament model. Numerical results calculated in this approach are compared with those determined from an accurate solution of the Grad-Shafranov equation, subject to a similar set of magnetic and pressure measurement constraints.

  12. Apparent directional spectral emissivity determination of semitransparent materials

    NASA Astrophysics Data System (ADS)

    Chun-Yang, Niu; Hong, Qi; Ya-Tao, Ren; Li-Ming, Ruan

    2016-04-01

    An inverse estimation method and corresponding measurement system are developed to measure the apparent spectral directional emissivities of semitransparent materials. The normal spectral emissivity and transmissivity serve as input for the inverse analysis. Consequently, the refractive index and absorption coefficient of the semitransparent material could be retrieved by using the pseudo source adding method as the forward method and the stochastic particle swarm optimization algorithm as the inverse method. Finally, the arbitrary apparent spectral directional emissivity of semitransparent material is estimated by using the pseudo source adding method given the retrieval refractive index and absorption coefficient. The present system has the advantage of a simple experimental structure, high accuracy, and excellent capability to measure the emissivity in an arbitrary direction. Furthermore, the apparent spectral directional emissivity of sapphire at 773 K is measured by using this system in a spectral range of 3 μm–12 μm and a viewing range of 0°–90°. The present method paves the way for a new directional spectral emissivity measurement strategy. Project supported by the National Natural Science Foundation of China (Grant Nos. 51476043 and 51576053) and the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (Grant No. 51421063).

  13. Directly heated high surface area solid phase microextraction sampler for rapid field forensic analyses.

    PubMed

    Ramsey, Scott A; Mustacich, Robert V; Smith, Philip A; Hook, Gary L; Eckenrode, Brian A

    2009-11-01

    A high-surface area solid phase microextraction (HSA-SPME) sampler is described for dynamic sampling at high air velocities (up to several hundred centimeters per second). The sampling device consists of a thin wire coated with carboxen/polydimethylsiloxane (carboxen/PDMS) material, wound in the annular space between two concentric glass tubes, providing a large trapping surface from which analytes may then be thermally desorbed with little power consumption upon resistive heating of the wire. Desorbed analytes are focused and reconcentrated on a microtrap that is subsequently resistively heated to introduce analytes for GC or GC/MS analysis. Benzene, toluene, ethylbenzene, and xylenes (BTEX) included in a 39-component toxic organics (TO-14) gas mixture were used to evaluate the efficiency of the HSA-SPME sampler. Quantitation of trace-level BTEX compounds present during weapons cleaning was completed using stepwise calibration. Detection limits of 0.2-6.9 pptr(v) were observed for these analytes using single ion monitoring GC/MS analysis, and an improvement in sensitivity of several orders of magnitude was achieved when compared to standard dynamic flow SPME with a commercially available 10 mm carboxen/PDMS fiber. The potential for rapid analyte uptake and improved sensitivity using the HSA-SPME design will make it possible to rapidly collect and analyze VOC samples in field settings using a portable hand-held pump and a small, low power GC/MS instrument. This system will be especially useful for situations involving forensics, public safety, and military defensive or intelligence needs where rapid, sensitive detection of airborne analytes is required. PMID:19795869

  14. Genetically Encoded Cyclopropene Directs Rapid, Photoclick Chemistry-Mediated Protein Labeling in Mammalian Cells

    PubMed Central

    Yu, Zhipeng; Pan, Yanchao; Wang, Zhiyong; Wang, Jiangyun; Lin, Qing

    2012-01-01

    Genetic incorporation of a cyclopropene amino acid, Nε-(1-methylcycloprop-2-enecarboxamido)-lysine (CpK), into sperm whale myoglobin site-specifically in E. coli as well as enhanced green fluorescent protein in mammalian cells was achieved through amber codon suppression employing an orthogonal aminoacyl-tRNA synthetase/tRNACUA pair. Because of its high ring strain, cyclopropene exhibited fast reaction kinetics (up to 58 ± 16 M−1 s−1) in the photoclick reaction and allowed rapid (~ 2 min) bioorthogonal labeling of proteins in mammalian cells. PMID:22997015

  15. An experiment for determining the Euler load by direct computation

    NASA Technical Reports Server (NTRS)

    Thurston, Gaylen A.; Stein, Peter A.

    1986-01-01

    A direct algorithm is presented for computing the Euler load of a column from experimental data. The method is based on exact inextensional theory for imperfect columns, which predicts two distinct deflected shapes at loads near the Euler load. The bending stiffness of the column appears in the expression for the Euler load along with the column length, therefore the experimental data allows a direct computation of bending stiffness. Experiments on graphite-epoxy columns of rectangular cross-section are reported in the paper. The bending stiffness of each composite column computed from experiment is compared with predictions from laminated plate theory.

  16. Genetically encoded norbornene directs site-specific cellular protein labelling via a rapid bioorthogonal reaction

    NASA Astrophysics Data System (ADS)

    Lang, Kathrin; Davis, Lloyd; Torres-Kolbus, Jessica; Chou, Chungjung; Deiters, Alexander; Chin, Jason W.

    2012-04-01

    The site-specific incorporation of bioorthogonal groups via genetic code expansion provides a powerful general strategy for site-specifically labelling proteins with any probe. However, the slow reactivity of the bioorthogonal functional groups that can be encoded genetically limits the utility of this strategy. We demonstrate the genetic encoding of a norbornene amino acid using the pyrrolysyl tRNA synthetase/tRNACUA pair in Escherichia coli and mammalian cells. We developed a series of tetrazine-based probes that exhibit ‘turn-on’ fluorescence on their rapid reaction with norbornenes. We demonstrate that the labelling of an encoded norbornene is specific with respect to the entire soluble E. coli proteome and thousands of times faster than established encodable bioorthogonal reactions. We show explicitly the advantages of this approach over state-of-the-art bioorthogonal reactions for protein labelling in vitro and on mammalian cells, and demonstrate the rapid bioorthogonal site-specific labelling of a protein on the mammalian cell surface.

  17. Rapid and reversible knockdown of endogenous proteins by peptide-directed lysosomal degradation

    PubMed Central

    Fan, Xuelai; Jin, Wu Yang; Lu, Jie; Wang, Jin; Wang, Yu Tian

    2014-01-01

    Rapid and reversible methods for altering the level of endogenous proteins are critically important for studying biological systems and developing therapeutics. Here, we describe a membrane permeable targeting peptide-based method that rapidly and reversibly knocks down endogenous proteins through chaperone-mediated autophagy in vitro and in vivo. We demonstrated the specificity, efficacy and generalizability of the method by showing efficient knockdown of various proteins including death associated protein kinase 1 (160kDa), scaffolding protein PSD-95 (95kDa) and α-synuclein (18kDa) with their respective targeting peptides in a dose-, time- and lysosomal activity-dependent manner in neuronal cultures. More significantly, we showed that when given systemically, the peptide system efficiently knocked down the targeted protein in the brain of intact rats. Our study provides a robust and convenient research tool to manipulate endogenous protein levels, and may also lead to the development of protein knockdown-based novel therapeutics for treating various human diseases. PMID:24464042

  18. Direct imprinting of porous substrates: a rapid and low-cost approach for patterning porous nanomaterials.

    PubMed

    Ryckman, Judson D; Liscidini, Marco; Sipe, J E; Weiss, S M

    2011-05-11

    This work describes a technique for one-step, direct patterning of porous nanomaterials, including insulators, semiconductors, and metals without the need for intermediate polymer processing or dry etching steps. Our process, which we call "direct imprinting of porous substrates (DIPS)", utilizes reusable stamps with micro- and nanoscale features that are applied directly to a porous material to selectively compress or crush the porous network. The stamp pattern is transferred to the porous material with high fidelity, vertical resolution below 5 nm, and lateral resolution below 100 nm. The process is performed in less than one minute at room temperature and at standard atmospheric pressure. We have demonstrated structures ranging from subwavelength optical components to microparticles and present exciting avenues for applications including surface-enhanced Raman spectroscopy (SERS), label-free biosensors, and drug delivery. PMID:20849094

  19. Unsaturated hydraulic parameters determined from direct and indirect methods

    SciTech Connect

    Flint, Lorraine E.; Hudson, David B.; Flint, Alan L.

    1997-10-22

    Hydraulic parameters are required for numerical simulations of unsaturated flow at Yucca Mountain, a vertically heterogeneous volcanic site for a potential high-level waste repository in the desert southwest. In this paper, direct measurements of the unsaturated hydraulic conductivity using a centrifuge with a specialized rotor are compared to those estimated using a predictive conductivity equation and two methods of measuring moisture retention.

  20. Determining the Bauschinger effect using the direct impact technique

    NASA Astrophysics Data System (ADS)

    Bragov, A. M.; Konstantinov, A. Yu.; Lomunov, A. K.

    2010-08-01

    A new simple method for quantitatively evaluating the dynamic Bauschinger effect has been developed based on the measurement of elastoplastic loading-unloading profiles for a sample dynamically loaded by direct impact. The proposed method has been verified by testing a D16 aluminum alloy.

  1. Subcellular distribution of enzymes determined by rapid digitonin fractionation of isolated hepatocytes.

    PubMed

    Janski, A M; Cornell, N W

    1980-02-15

    Conditions were determined for rapid separation of cytosolic and mitochondrial compartments by digitonin fractionation of rat hepatocytes. The minimum time required for separation of mitochondrial and cytosolic enzyme markers decreased rapidly with increasing temperature. Kyro EOB, a non-ionic detergent, increases the release of cytosolic enzymes, particularly at lower temperatures. Experimental procedures are described for greater than 90% release of cytosolic enzymes and less than 2% release of mitochondrial enzymes in 3s. By using appropriate concentrations of digitonin and Kyro EOB in a fractionation medium maintained at 1 degrees C and a minimum time of exposure to the medium, nearly separate patterns of release were obtained for enzyme markers for the cytosol, mitochondrial matrix and mitochondrial intermembrane space. The distribution of enzymes that exist in more than one of these compartments was quantified by comparing their rates of release with those of marker enzymes. The cytosol/mitochondrial-matrix distributions for such enzymes in hepatocytes from starved rats were 16%/84% for aspartate aminotransferase, 34%/66% for fumarase and 77%/23% for ATP citrate lyase. In hepatocytes from rats that were induced to synthesize ATP citrate lyase by starvation and re-feeding, the ratio had increased to 95%/5%. The maximum cytosol/intermembrane-space ratio for adenylate kinase was 8%/92%. A procedure is also described for treating commercial digitonin that increases its solubility in water from about 1mg/ml to more than 800mg/ml. PMID:7378059

  2. Subcellular distribution of enzymes determined by rapid digitonin fractionation of isolated hepatocytes

    PubMed Central

    Janski, Alvin M.; Cornell, Neal W.

    1980-01-01

    Conditions were determined for rapid separation of cytosolic and mitochondrial compartments by digitonin fractionation of rat hepatocytes. The minimum time required for separation of mitochondrial and cytosolic enzyme markers decreased rapidly with increasing temperature. Kyro EOB, a non-ionic detergent, increases the release of cytosolic enzymes, particularly at lower temperatures. Experimental procedures are described for greater than 90% release of cytosolic enzymes and less than 2% release of mitochondrial enzymes in 3s. By using appropriate concentrations of digitonin and Kyro EOB in a fractionation medium maintained at 1°C and a minimum time of exposure to the medium, nearly separate patterns of release were obtained for enzyme markers for the cytosol, mitochondrial matrix and mitochondrial intermembrane space. The distribution of enzymes that exist in more than one of these compartments was quantified by comparing their rates of release with those of marker enzymes. The cytosol/mitochondrial-matrix distributions for such enzymes in hepatocytes from starved rats were 16%/84% for aspartate aminotransferase, 34%/66% for fumarase and 77%/23% for ATP citrate lyase. In hepatocytes from rats that were induced to synthesize ATP citrate lyase by starvation and re-feeding, the ratio had increased to 95%/5%. The maximum cytosol/intermembrane-space ratio for adenylate kinase was 8%/92%. A procedure is also described for treating commercial digitonin that increases its solubility in water from about 1mg/ml to more than 800mg/ml. PMID:7378059

  3. Rapid determination of uranium isotopes in urine by inductively coupled plasma-mass spectrometry.

    PubMed

    Shi, Y; Dai, X; Collins, R; Kramer-Tremblay, S

    2011-08-01

    Following a radiological or nuclear emergency involving uranium exposure, rapid analytical methods are needed to analyze the concentration of uranium isotopes in human urine samples for early dose assessment. The inductively coupled plasma mass spectrometry (ICP-MS) technique, with its high sample throughput and high sensitivity, has advantages over alpha spectrometry for uranium urinalysis after minimum sample preparation. In this work, a rapid sample preparation method using an anion exchange chromatographic column was developed to separate uranium from the urine matrix. A high-resolution sector field ICP-MS instrument, coupled with a high sensitivity desolvation sample introduction inlet, was used to determine uranium isotopes in the samples. The method can analyze up to 24 urine samples in two hours with the limits of detection of 0.0014, 0.10, and 2.0 pg mL(-1) for (234)U, (235)U, and (238)U, respectively, which meet the requirement for isotopic analysis of uranium in a radiation emergency. PMID:21709502

  4. [Rapid determination of aspartame in compound sweetening by reversed-phase high performance liquid chromatography].

    PubMed

    Zhang, R; Jiang, M

    1997-11-01

    A method for rapid determination of Aspartame in compound sweetening by reversed-phase high performance liquid chromatography is presented. Aspartame in compound sweetening was separated in a short column (Ultrasphere XL-ODS, 3 microm, 4.6 mm x 70 mm) by using CH3OH-0.02 mol/L NH4Ac as mobile phase. The flow rate was 0.8 mL/min. Detection was performed with UV detector at 220 nm. The injection volume was 20 microL. It was qualitatively analysed by UV scanning at a wavelength range of 200-350 nm under no-stop flow according to their retention time. Quantitative analysis was carried out by measuring peak height and comparing it with external standard. The minimum detectable amount was 5 microg/L. The linear range of the calibration curve was 40-200 mg/L. The average recovery of Aspartame was 92%. The relative standard deviation was 2.9%. This method is simple, rapid and sensitive. PMID:15739346

  5. Fully automated VLBI analysis with c5++ for ultra-rapid determination of UT1

    NASA Astrophysics Data System (ADS)

    Hobiger, Thomas; Otsubo, Toshimichi; Sekido, Mamoru; Gotoh, Tadahiro; Kubooka, Toshihiro; Takiguchi, Hiroshi

    2010-12-01

    VLBI is the only space-geodetic technique which gives direct access to the Earth's phase of rotation, i.e. universal time UT1. Beside multi-baseline sessions, regular single baseline VLBI experiments are scheduled in order to provide estimates of UT1 for the international space community. Although the turn-around time of such sessions is usually much shorter and results are available within one day after the data were recorded, lower latency of UT1 results is still requested. Based on the experience gained over the last two years, an automated analysis procedure was established. The main goal was to realize fully unattended operation and robust estimation of UT1. Our new analysis software, named c5++, is capable of interfacing directly with the correlator output, carries out all processing stages without human interaction and provides the results for the scientific community or dedicated space applications. Moreover, the concept of ultra-rapid VLBI sessions can be extended to include further well-distributed stations, in order to obtain the polar motion parameters with the same latency and provide an up-to-date complete set of Earth orientation parameters for navigation of space and satellite missions.

  6. Rapid determination of ions by combined solid-phase extraction--diffuse reflectance spectroscopy

    NASA Technical Reports Server (NTRS)

    Fritz, James S.; Arena, Matteo P.; Steiner, Steven A.; Porter, Marc D.

    2003-01-01

    We introduce colorimetric solid-phase extraction (C-SPE) for the rapid determination of selected ions. This new technique links the exhaustive concentration of an analyte by SPE onto a membrane disk surface for quantitative measurement with a hand-held diffuse reflectance spectrometer. The concentration/measurement procedure is complete in approximately 1 min and can be performed almost anywhere. This method has been used to monitor iodine and iodide in spacecraft water in the 0.1-5.0 ppm range and silver(I) in the range of 5.0-1000 microg/l. Applications to the trace analysis of copper(II), nickel(II), iron(III) and chromium(VI) are described. Studies on the mechanism of extraction showed that impregnation of the disk with a surfactant as well as a complexing reagent results in uptake of additional water, which markedly improves the extraction efficiency.

  7. Rapid determination of rifaximin on dried blood spots by LC-ESI-MS.

    PubMed

    Rao, R Nageswara; Vali, R Mastan; Ramachandra, Bondigalla; Maurya, Pawan K

    2011-11-01

    The use of blood spot collection cards is a simple way to obtain specimens for therapeutic drug monitoring, assessing adherence to medications and preventing toxicity in a clinical setting. A high-throughput liquid chromatography-electrospray ionization mass spectrometric (LC-ESI-MS) method for determination of rifaximin on dried blood spots (DBS) was developed and validated. It involves solvent extraction of a punch of DBS followed by reversed-phase LC on a monolithic column consisting of a silica rod with bimodal pore structure and detection by ESI-MS. Rifampicin was used as an internal standard (IS). The run time was within 5.0 min with a very low back-pressure at a flow rate of 0.5 mL/min. The assay was linear from 0.1 to 10 ng/mL. The mean recovery was 98.42%. The developed method is very simple, rapid and useful for clinical applications. PMID:21287584

  8. Evaluation of a rapid method of determination of plasma fibrinogen in swine.

    PubMed

    Fontaine, M; McSherry, B J; Valli, V E

    1977-04-01

    An evaluation was made of a rapid semiautomated method for determining fibrinogen level in swine plasma. This method, referred to as thrombin time method or fibrometer method, is based on the principle that when thrombin is added to suitably diluted plasma, the time of clotting is linearly related to the fibrinogen concentration. The linear regression model for the standard curve prepared using swine plasma had an r value of 0.998. A comparison between the fibrometer and the Grannis methods done on 189 swine plasma samples showed good correlation between these two mehtods (r value 0.847). It was concluded that although the fibrometer method may not be as precise as the Grannis method, it would still be acceptable for clinical use in swine. PMID:861838

  9. A novel correlation for rapid lactose determination in milk by a cryoscopic technique.

    PubMed

    Colinas, Carmen; Barrera, Ignacio; Blanco, Carlos A

    2006-01-01

    Residual lactose in special milk was systematically determined for people with lactose intolerance by means of a rapid on-line measurement of the cryoscopic point. A proposed cryoscopic procedure was compared to 2 conventional yet highly laborious methods: the enzymatic procedure with spectrophotometric control and the polarimetric method. Several experiments with different mixtures of both semi-skimmed and low-lactose milk were performed. A lineal relationship was found between lactose concentration and freezing point, the analytical equation for which shows a close relationship regarding the 3 methods used. The advantages of the cryoscopic procedure include speed in obtaining results and operational simplicity at a low cost, better monitoring of enzymatic hydrolysis kinetics, and greater control over the production process for delactosed milk. The equation obtained also enables prediction of the lactose percentage in commercial milk by a simple measurement of freezing point. PMID:17225605

  10. Rapid method for determining concentrations of Bayer 73 in water during lampricide treatments

    USGS Publications Warehouse

    Dawson, V.K.; Harman, P.D.; Schultz, D.P.; Allen, J.L.

    1978-01-01

    Two simple, rapid, sensitive methods were developed for determining the concentration of the lampricide 2',5-dichloro-4'-nitrosalicylanilide (Bayer 73) in stream water. Bayer 73 was extracted from acidified water samples with chloroform and then hydrolyzed to 2-chloro-4-nitroaniline (CNA) with either acid or base. The CNA was diazotized with sodium nitrite, and an azo dye was formed with either N-( 1-naphthyl) ethylenediamine dihydrochloride (after acid hydrolysis) or 1-naphthol (after base hydrolysis). There was no interference from the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) in either method. Standard curves were prepared with untreated water to compensate for interfering substances that occurred naturally in some streams. The methods were sensitive to about 0.005 mg/L (ppm). Time required for analysis of a sample ranged from 25 min to 1 h.