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Sample records for concentrations eretic method

  1. A report of an aquatic beetle Eretes griseus (Fabricius, 1781 (Coleoptera: Dytiscidae: Dytiscinae: Eretini from the Western Ghats and other parts of Maharashtra, India

    Directory of Open Access Journals (Sweden)

    Sayali D. Sheth

    2014-11-01

    Full Text Available This note is the first authentic record of the dytiscid species Eretes griseus (Fabricius, 1781 from the Western Ghats of Maharashtra, India. It was found only from three localities (essentially isolated temporary pools out of 50+ localities sampled so far in the year 2013-2014. We provide light microscopic images of the habitus, SEM images of important diagnostic characteristics and also clarify the status and distribution of this species in India. 

  2. Methods and systems for concentrated solar power

    Science.gov (United States)

    Ma, Zhiwen

    2016-05-24

    Embodiments described herein relate to a method of producing energy from concentrated solar flux. The method includes dropping granular solid particles through a solar flux receiver configured to transfer energy from concentrated solar flux incident on the solar flux receiver to the granular solid particles as heat. The method also includes fluidizing the granular solid particles from the solar flux receiver to produce a gas-solid fluid. The gas-solid fluid is passed through a heat exchanger to transfer heat from the solid particles in the gas-solid fluid to a working fluid. The granular solid particles are extracted from the gas-solid fluid such that the granular solid particles can be dropped through the solar flux receiver again.

  3. Portable method of measuring gaseous acetone concentrations.

    Science.gov (United States)

    Worrall, Adam D; Bernstein, Jonathan A; Angelopoulos, Anastasios P

    2013-08-15

    Measurement of acetone in human breath samples has been previously shown to provide significant non-invasive diagnostic insight into the control of a patient's diabetic condition. In patients with diabetes mellitus, the body produces excess amounts of ketones such as acetone, which are then exhaled during respiration. Using various breath analysis methods has allowed for the accurate determination of acetone concentrations in exhaled breath. However, many of these methods require instrumentation and pre-concentration steps not suitable for point-of-care use. We have found that by immobilizing resorcinol reagent into a perfluorosulfonic acid polymer membrane, a controlled organic synthesis reaction occurs with acetone in a dry carrier gas. The immobilized, highly selective product of this reaction (a flavan) is found to produce a visible spectrum color change which could measure acetone concentrations to less than ppm. We here demonstrate how this approach can be used to produce a portable optical sensing device for real-time, non-invasive acetone analysis. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Prediction Methods for Blood Glucose Concentration

    DEFF Research Database (Denmark)

    , but the insulin amount is chosen using factors that account for this expectation. The increasing availability of more accurate continuous blood glucose measurement (CGM) systems is attracting much interest to the possibilities of explicit prediction of future BG values. Against this background, in 2014 a two......-day workshop on the design, use and evaluation of prediction methods for blood glucose concentration was held at the Johannes Kepler University Linz, Austria. One intention of the workshop was to bring together experts working in various fields on the same topic, in order to shed light from different angles...... Freckmann et al. discusses performance metrics used to characterize the accuracy of continuous glucose measurement devices. This topic is highly relevant for prediction models since many of them rely on the data given by the continuous sensors which are previously calibrated with blood glucose meter...

  5. Prediction Methods for Blood Glucose Concentration

    DEFF Research Database (Denmark)

    “Recent Results on Glucose–Insulin Predictions by Means of a State Observer for Time-Delay Systems” by Pasquale Palumbo et al. introduces a prediction model which in real time predicts the insulin concentration in blood which in turn is used in a control system. The method is tested in simulation......Standard diabetes insulin therapy for type 1 diabetes and late stages of type 2 is based on the expected development of blood glucose (BG) both as a consequence of the metabolic glucose consumption as well as of meals and exogenous insulin intake. Traditionally, this is not done explicitly......, but the insulin amount is chosen using factors that account for this expectation. The increasing availability of more accurate continuous blood glucose measurement (CGM) systems is attracting much interest to the possibilities of explicit prediction of future BG values. Against this background, in 2014 a two...

  6. Protein solutions: concentration by a rapid method.

    Science.gov (United States)

    Blatt, W F; Feinberg, M P; Hopfenberg, H B; Saravis, C A

    1965-10-08

    Protein solutions were concentrated, with no evidence of denaturation, by means of membranes formed from the complex interaction product of polyanions and polycations (Diaplex). The technique is considerably more rapid than conventional ultrafiltration with Visking tubing.

  7. Method of concentrating radioactive liquid waste

    International Nuclear Information System (INIS)

    Yasumura, Keijiro

    1990-01-01

    Radioactive liquid wastes generated from nuclear power facilities are caused to flow into a vessel incorporated with first hydrophobic porous membranes. Then, the radioactive liquid wastes are passed through the first hydrophobic porous membranes under an elevated or reduced pressure to remove fine particles contained in the liquid wastes. The radioactive liquid wastes passed through the first membranes are stored in a temporary store a vessel and steams generated under heating are passed through the second hydrophobic porous membranes and then cooled and concentrated as condensates. In this case, the first and the second hydrophobic porous membranes have a property of passing steams but not water and, for example, are made of tetrafluoroethylen resin type thin membranes. Accordingly, since the fine particles can be removed by the first hydrophobic porous membranes, lowering of the concentration rate due to the deposition of solid contents to the membranes upon concentration can be prevented. (I.S.)

  8. Methods for macro concentration speciation (>106 M)

    International Nuclear Information System (INIS)

    2001-01-01

    The range of topics covered by the term 'speciation' varies from the determination of isotopic composition, through whether an element or nuclide is present and under which form, to the full identification of the molecular compound present or the isolation of species. Therefore, it is quite understandable that a rather large range of techniques may be applicable for speciation purposes and that none may be sufficient by itself to cover all purposes. We tried in this report to review on technologies available for speciation purposes in nuclear fuel cycle activities and to provide a reference document to guide researchers in choosing the most useful technique for his purposes by summarizing their characteristics. Particular attention was given to highlight the advantages and disadvantages/limitations of a given technique as well as, when suitable, expected or necessary future improvements. It was also attempted to indicate a 'recommended' application field, though this was not an easy task. In the present part, we concentrate on techniques available for macro concentration speciation with an arbitrary limit fixed around 10 -6 M. However, one should be aware that some of the techniques discussed in the present may be also applicable for lower concentration (overlap with over Partim. of the whole report) and vice-versa. Then, we consider that the scope of the present can only be achieved considering the whole parts discussed at the OECD/NEA Workshop on evaluation of speciation technology held in October 1999 at JAERI/Tokai-mura. (author)

  9. Quantification of organic acids in beer by nuclear magnetic resonance (NMR)-based methods

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, J.E.A. [CICECO-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Erny, G.L. [CESAM - Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Barros, A.S. [QOPNAA-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Esteves, V.I. [CESAM - Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Brandao, T.; Ferreira, A.A. [UNICER, Bebidas de Portugal, Leca do Balio, 4466-955 S. Mamede de Infesta (Portugal); Cabrita, E. [Department of Chemistry, New University of Lisbon, 2825-114 Caparica (Portugal); Gil, A.M., E-mail: agil@ua.pt [CICECO-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal)

    2010-08-03

    The organic acids present in beer provide important information on the product's quality and history, determining organoleptic properties and being useful indicators of fermentation performance. NMR spectroscopy may be used for rapid quantification of organic acids in beer and different NMR-based methodologies are hereby compared for the six main acids found in beer (acetic, citric, lactic, malic, pyruvic and succinic). The use of partial least squares (PLS) regression enables faster quantification, compared to traditional integration methods, and the performance of PLS models built using different reference methods (capillary electrophoresis (CE), both with direct and indirect UV detection, and enzymatic essays) was investigated. The best multivariate models were obtained using CE/indirect detection and enzymatic essays as reference and their response was compared with NMR integration, either using an internal reference or an electrical reference signal (Electronic REference To access In vivo Concentrations, ERETIC). NMR integration results generally agree with those obtained by PLS, with some overestimation for malic and pyruvic acids, probably due to peak overlap and subsequent integral errors, and an apparent relative underestimation for citric acid. Overall, these results make the PLS-NMR method an interesting choice for organic acid quantification in beer.

  10. Discrete Spectral Local Measurement Method for Testing Solar Concentrators

    Directory of Open Access Journals (Sweden)

    Huifu Zhao

    2012-01-01

    Full Text Available In order to compensate for the inconvenience and instability of outdoor photovoltaic concentration test system which are caused by the weather changes, we design an indoor concentration test system with a large caliber and a high parallelism, and then verify its feasibility and scientificity. Furthermore, we propose a new concentration test method: the discrete spectral local measurement method. A two-stage Fresnel concentration system is selected as the test object. The indoor and the outdoor concentration experiments are compared. The results show that the outdoor concentration efficiency of the two-stage Fresnel concentration system is 85.56%, while the indoor is 85.45%. The two experimental results are so close that we can verify the scientificity and feasibility of the indoor concentration test system. The light divergence angle of the indoor concentration test system is 0.267° which also matches with sunlight divergence angle. The indoor concentration test system with large diameter (145 mm, simple structure, and low cost will have broad applications in solar concentration field.

  11. An Automatic High Efficient Method for Dish Concentrator Alignment

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2014-01-01

    for the alignment of faceted solar dish concentrator. The isosceles triangle configuration of facet’s footholds determines a fixed relation between light spot displacements and foothold movements, which allows an automatic determination of the amount of adjustments. Tests on a 25 kW Stirling Energy System dish concentrator verify the feasibility, accuracy, and efficiency of our method.

  12. Methods of gas hydrate concentration estimation with field examples

    Digital Repository Service at National Institute of Oceanography (India)

    Kumar, D.; Dash, R.; Dewangan, P.

    accuracy, sensitivity and cost issue. Seismic methods are the most common but the estimated gas hydrate concentration can be less accurate than coring method. Although coring method has certain difficulty such as the core sampling, preserving samples... general. The gas saturation is ignored for simplification, but in the case of free gas and gas hydrate coexisting both can be simultaneously estimated. The steps for hydrate saturation estimation in method 1 are: 1) first create a table of modeled seismic...

  13. Methods and devices for high-throughput dielectrophoretic concentration

    Science.gov (United States)

    Simmons, Blake A.; Cummings, Eric B.; Fiechtner, Gregory J.; Fintschenko, Yolanda; McGraw, Gregory J.; Salmi, Allen

    2010-02-23

    Disclosed herein are methods and devices for assaying and concentrating analytes in a fluid sample using dielectrophoresis. As disclosed, the methods and devices utilize substrates having a plurality of pores through which analytes can be selectively prevented from passing, or inhibited, on application of an appropriate electric field waveform. The pores of the substrate produce nonuniform electric field having local extrema located near the pores. These nonuniform fields drive dielectrophoresis, which produces the inhibition. Arrangements of electrodes and porous substrates support continuous, bulk, multi-dimensional, and staged selective concentration.

  14. Effect of Concentrated Language Encounter Method in Developing ...

    African Journals Online (AJOL)

    The paper examined the effect of concentrated language encounter method in developing sight word recognition skill in primary school pupils in cross river state. The purpose of the study was to find out the effect of Primary One pupils' reading level, English sight word recognition skill. It also examine the extent to which the ...

  15. Effect of Concentrated Language Encounter Method in Development ...

    African Journals Online (AJOL)

    Effect of Concentrated Language Encounter Method in Development of Beginning Literacy Skills of Letter KnowledgeWords Among Primary School Pupils in Cross River State. ... The instrument used included the Letter Knowledge Test (LKT) which was a standardized instrument, used in several prior studies in English.

  16. Effects of Concentrated Language Encounter Method in Developing ...

    African Journals Online (AJOL)

    Effects of Concentrated Language Encounter Method in Developing Comprehension Skills in Primary School Pupils in Cross River State, Nigeria. ... Lwati: A Journal of Contemporary Research ... The purpose of the study was to find out the effects of primary one pupils' reading level, English comprehension skill.

  17. Office-based sperm concentration: A simplified method for ...

    African Journals Online (AJOL)

    Methods: Semen samples from 51 sperm donors were used. Following swim-up separation, the sperm concentration of the retrieved motile fraction was counted, as well as progressive motile sperm using a standardised wet preparation. The number of sperm in a 10 μL droplet covered with a 22 × 22 mm coverslip was ...

  18. Magnetic flux concentration methods for magnetic energy harvesting module

    Directory of Open Access Journals (Sweden)

    Wakiwaka Hiroyuki

    2013-01-01

    Full Text Available This paper presents magnetic flux concentration methods for magnetic energy harvesting module. The purpose of this study is to harvest 1 mW energy with a Brooks coil 2 cm in diameter from environmental magnetic field at 60 Hz. Because the harvesting power is proportional to the square of the magnetic flux density, we consider the use of a magnetic flux concentration coil and a magnetic core. The magnetic flux concentration coil consists of an air­core Brooks coil and a resonant capacitor. When a uniform magnetic field crossed the coil, the magnetic flux distribution around the coil was changed. It is found that the magnetic field in an area is concentrated larger than 20 times compared with the uniform magnetic field. Compared with the air­core coil, our designed magnetic core makes the harvested energy ten­fold. According to ICNIRP2010 guideline, the acceptable level of magnetic field is 0.2 mT in the frequency range between 25 Hz and 400 Hz. Without the two magnetic flux concentration methods, the corresponding energy is limited to 1 µW. In contrast, our experimental results successfully demonstrate energy harvesting of 1 mW from a magnetic field of 0.03 mT at 60 Hz.

  19. Method and Apparatus for Concentrating Vapors for Analysis

    Science.gov (United States)

    Grate, Jay W.; Baldwin, David L.; Anheier, Jr., Norman C.

    2008-10-07

    An apparatus and method are disclosed for pre-concentrating gaseous vapors for analysis. The invention finds application in conjunction with, e.g., analytical instruments where low detection limits for gaseous vapors are desirable. Vapors sorbed and concentrated within the bed of the apparatus can be thermally desorbed achieving at least partial separation of vapor mixtures. The apparatus is suitable, e.g., for preconcentration and sample injection, and provides greater resolution of peaks for vapors within vapor mixtures, yielding detection levels that are 10-10,000 times better than for direct sampling and analysis systems. Features are particularly useful for continuous unattended monitoring applications.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-10-13

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

  1. Method of increased bioethanol concentration with reduced heat consumption

    International Nuclear Information System (INIS)

    Bremers, G.; Blija, A.

    2003-01-01

    Ethanol dehydration applying method of non-reflux saline distillation was conduced on a laboratory scale and in bigger pilot equipment. Results make possible recommend new method for the increased of ethanol concentration. Heat consumption reduced by 50% and cooling water consumption by 90 % when the non-reflux distillation was applied. Reflux flow in the column is replacing with contact mass, which consist from saline layer and seclude medium. Basis diagram of ethanol non-reflux saline distillation was established. Distillation equipment and number of plates in the column can calculate using basis diagram. Absolute ethanol can obtain with non-reflux saline distillation. Absolute ethanol use in produce of biofuel (author)

  2. Using nuclear methods for analyzing materials and determining concentration gradients

    International Nuclear Information System (INIS)

    Darras, R.

    After reviewing the various type of nuclear chemical analysis methods, the possibilities of analysis by activation and direct observation of nuclear reactions are specifically described. These methods make it possible to effect analyses of trace-elements or impurities, even as traces, in materials, with selectivity, accuracy and great sensitivity. This latter property makes them advantageous too for determining major elements in small quantities of available matter. Furthermore, they lend themselves to carrying out superficial analyses and the determination of concentration gradients, given the careful choice of the nature and energy of the incident particles. The paper is illustrated with typical examples of analyses on steels, pure iron, refractory metals, etc [fr

  3. Concentration of bioaerosols in composting plants using different quantification methods.

    Science.gov (United States)

    van Kampen, Vera; Sander, Ingrid; Liebers, Verena; Deckert, Anja; Neumann, Heinz-Dieter; Buxtrup, Martin; Willer, Eckart; Felten, Christian; Jäckel, Udo; Klug, Kerstin; Brüning, Thomas; Raulf, Monika; Bünger, Jürgen

    2014-07-01

    Bioaerosols (organic dusts) containing viable and non-viable microorganisms and their metabolic products can lead to adverse health effects in exposed workers. Standard quantification methods of airborne microorganisms are mainly based on cultivation, which often underestimates the microbial burden. The aim of the study was to determine the microbial load in German composting plants with different, mainly cultivation-independent, methods. Second purpose was to evaluate which working areas are associated with higher or lower bioaerosol concentrations. A total of 124 inhalable dust samples were collected at different workplaces in 31 composting plants. Besides the determination of inhalable dust, particles, and total cell numbers, antigen quantification for moulds (Aspergillus fumigatus, Aspergillus versicolor, Penicillium chrysogenum, and Cladosporium spp.) and mites was performed. Concentrations of β-glucans as well as endotoxin and pyrogenic activities were also measured. The number of colony forming units (cfu) was determined by cultivation of moulds and actinomycetes in 36 additional dust samples. With the exception of particle numbers, concentrations of all determined parameters showed significant correlations (P parameters were measured highest in dusty working areas like next to the shredder and during processing with the exception of Cladosporium antigens that were found in the highest concentrations in the delivery area. The lowest concentrations of dust, particles, antigens, and pyrogenic activity were determined in wheel loader cabins (WLCs), which were equipped with an air filtration system. It was possible to assess the microbial load of air in composting plants with different quantification methods. Since allergic and toxic reactions may be also caused by nonliving microorganisms, cultivation-independent methods may provide additional information about bioaerosol composition. In general, air filtration reduced the bioaerosol exposure shown in WLCs

  4. The active titration method for measuring local hydroxyl radical concentration

    Science.gov (United States)

    Sprengnether, Michele; Prinn, Ronald G.

    1994-01-01

    We are developing a method for measuring ambient OH by monitoring its rate of reaction with a chemical species. Our technique involves the local, instantaneous release of a mixture of saturated cyclic hydrocarbons (titrants) and perfluorocarbons (dispersants). These species must not normally be present in ambient air above the part per trillion concentration. We then track the mixture downwind using a real-time portable ECD tracer instrument. We collect air samples in canisters every few minutes for roughly one hour. We then return to the laboratory and analyze our air samples to determine the ratios of the titrant to dispersant concentrations. The trends in these ratios give us the ambient OH concentration from the relation: dlnR/dt = -k(OH). A successful measurement of OH requires that the trends in these ratios be measureable. We must not perturb ambient OH concentrations. The titrant to dispersant ratio must be spatially invariant. Finally, heterogeneous reactions of our titrant and dispersant species must be negligible relative to the titrant reaction with OH. We have conducted laboratory studies of our ability to measure the titrant to dispersant ratios as a function of concentration down to the few part per trillion concentration. We have subsequently used these results in a gaussian puff model to estimate our expected uncertainty in a field measurement of OH. Our results indicate that under a range of atmospheric conditions we expect to be able to measure OH with a sensitivity of 3x10(exp 5) cm(exp -3). In our most optimistic scenarios, we obtain a sensitivity of 1x10(exp 5) cm(exp -3). These sensitivity values reflect our anticipated ability to measure the ratio trends. However, because we are also using a rate constant to obtain our (OH) from this ratio trend, our accuracy cannot be better than that of the rate constant, which we expect to be about 20 percent.

  5. Bacterial contamination of platelet concentrates: pathogen detection and inactivation methods

    Directory of Open Access Journals (Sweden)

    Dana Védy

    2009-04-01

    Full Text Available Whereas the reduction of transfusion related viral transmission has been a priority during the last decade, bacterial infection transmitted by transfusion still remains associated to a high morbidity and mortality, and constitutes the most frequent infectious risk of transfusion. This problem especially concerns platelet concentrates because of their favorable bacterial growth conditions. This review gives an overview of platelet transfusion-related bacterial contamination as well as on the different strategies to reduce this problem by using either bacterial detection or inactivation methods.

  6. Determination of deuterium concentration by falling drop method

    International Nuclear Information System (INIS)

    Kawai, Hiroshi; Morishima, Hiroshige; Koga, Taeko; Niwa, Takeo; Fujii, Takashi.

    1976-01-01

    Falling drop method for determination of deuterium concentration in water sample was studied. The principle is the same as that developed by Kirshenbaum, I. in 1932. One drop of water sample falls down through a column filled with o-fluorotoluene at temperature of nearly 25 0 C. The falling time is, instead of using a stop-watch, measured with two light pulses led to a photomultiplier with mirrors, which make two pulse marks on moving chart paper. Distance between the two pulse marks is proportional to falling time. Instead of water filled double chambers of constant temperature equipped with heaters, thermostats and propellers for stirring, the column is dipped in circulating water supplied from a ''Thermoelectric'' made by ''Sharp'' company, which can circulate constant temperature water cooled or heated with thermoelements. Variation of the temperature is about 0.01 0 C. The range of deuterium concentration in our case was 20 -- 60D%. Sensitivity increased as the medium temperature decreased and as deuterium concentration of water sample increased. (auth.)

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

    Science.gov (United States)

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

    2009-12-01

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

  8. Evaluation of methods for monitoring air concentrations of hydrogen sulfide

    Directory of Open Access Journals (Sweden)

    Katarzyna Janoszka

    2013-06-01

    Full Text Available The development of different branches of industry and a growing fossil fuels mining results in a considerable emission of by-products. Major air pollutants are: CO, CO₂, SO₂, SO₃, H₂S, nitrogen oxides, as well as compounds of an organic origin. The main aspects of this paper is to review and evaluate methods used for monitoring of hydrogen sulfide in the air. Different instrumental techniques were discussed, electrochemical, chromatographic and spectrophotometric (wet and dry, to select the method most suitable for monitoring low levels of hydrogen sulfide, close to its odor threshold. Based on the literature review the method for H₂S determination in the air, involving absorption in aqueous zinc acetate and reaction with N,N-dimethylo-p-phenylodiamine and FeCl₃, has been selected and preliminary verified. The adopted method allows for routine measurements of low concentration of hydrogen sulfide, close to its odor threshold in workplaces and ambient air. Med Pr 2013;64(3:449–454

  9. Method of making a modular off-axis solar concentrator

    Science.gov (United States)

    Plesniak, Adam P.; Hall, John C.

    2017-05-23

    A method of making a solar concentrator may include forming a receiving wall having an elongated wall, a first side wall and a second side wall; attaching the first side wall and the second side wall to a reflecting wall to form a housing having an internal volume with an opening; forming a lip on the receiving wall and the reflecting wall; attaching a cover to the receiving wall and the reflecting wall at the lip to seal the opening into the internal volume, thereby creating a rigid structure; and mounting at least one receiver having at least one photovoltaic cell on the elongated wall to receive solar radiation entering the housing and reflected by the receiving wall, the receiver having an axis parallel with a surface normal of the photovoltaic cell, such that the axis is disposed at a non-zero angle relative to the vertical axis of the opening.

  10. Data Based Prediction of Blood Glucose Concentrations Using Evolutionary Methods.

    Science.gov (United States)

    Hidalgo, J Ignacio; Colmenar, J Manuel; Kronberger, Gabriel; Winkler, Stephan M; Garnica, Oscar; Lanchares, Juan

    2017-08-08

    Predicting glucose values on the basis of insulin and food intakes is a difficult task that people with diabetes need to do daily. This is necessary as it is important to maintain glucose levels at appropriate values to avoid not only short-term, but also long-term complications of the illness. Artificial intelligence in general and machine learning techniques in particular have already lead to promising results in modeling and predicting glucose concentrations. In this work, several machine learning techniques are used for the modeling and prediction of glucose concentrations using as inputs the values measured by a continuous monitoring glucose system as well as also previous and estimated future carbohydrate intakes and insulin injections. In particular, we use the following four techniques: genetic programming, random forests, k-nearest neighbors, and grammatical evolution. We propose two new enhanced modeling algorithms for glucose prediction, namely (i) a variant of grammatical evolution which uses an optimized grammar, and (ii) a variant of tree-based genetic programming which uses a three-compartment model for carbohydrate and insulin dynamics. The predictors were trained and tested using data of ten patients from a public hospital in Spain. We analyze our experimental results using the Clarke error grid metric and see that 90% of the forecasts are correct (i.e., Clarke error categories A and B), but still even the best methods produce 5 to 10% of serious errors (category D) and approximately 0.5% of very serious errors (category E). We also propose an enhanced genetic programming algorithm that incorporates a three-compartment model into symbolic regression models to create smoothed time series of the original carbohydrate and insulin time series.

  11. Image cytometer method for automated assessment of human spermatozoa concentration

    DEFF Research Database (Denmark)

    Egeberg, D L; Kjaerulff, S; Hansen, C

    2013-01-01

    In the basic clinical work-up of infertile couples, a semen analysis is mandatory and the sperm concentration is one of the most essential variables to be determined. Sperm concentration is usually assessed by manual counting using a haemocytometer and is hence labour intensive and may be subject...

  12. A neutronic method to determine low hydrogen concentrations in metals

    International Nuclear Information System (INIS)

    Bennun, Leonardo; Santisteban, Javier; Diaz-Valdes, J.; Granada, J.R.; Mayer, R.E.

    2007-01-01

    We propose a method for the non-destructive determination of low hydrogen content in metals. The method is based on measurements of neutron inelastic scattering combined with cadmium filters. Determination is simple and the method would allow to construct a mobile device, to perform the analysis 'in situ'. We give a brief description of the usual methods to determine low hydrogen contents in solids, paying special attention to those methods supported by neutron techniques. We describe the proposed method, calculations to achieve a better sensitivity, and experimental results

  13. Method for treatment of water containing low concentrations of mercury

    Science.gov (United States)

    Flood, D. J.; Kraynik, G. J.

    1973-01-01

    A process employing magnetic filtering techniques has been devised for treating water containing concentrations on the order of 1 microgram/cubic centimeter of atomic or ionic mercury. A laboratory-scale system has been operated and can reduce the mercury content of test solutions by as much as 90 percent.

  14. Method of processing concentrated liquid waste in nuclear power plant

    International Nuclear Information System (INIS)

    Hasegawa, Kazuyuki; Kitsukawa, Ryozo; Ohashi, Satoru.

    1988-01-01

    Purpose: To reduce the oxidizable material in the concentrated liquid wastes discharged from nuclear power plants. Constitution: Nitrate bacteria are added to liquid wastes in a storage tank for temporarily storing concentrated liquid wastes or relevant facilities thereof. That is, nitrites as the oxidizable material contained in the concentrated liquid wastes are converted into nitrate non-deleterious to solidification by utilizing biological reaction of nitrate bacteria. For making the conversion more effectively, required time for the biological reaction of the nitrate bacteria is maintained from the injection of nitrate bacteria to solidification, thereby providing advantageous conditions for the propagation of the nitrate bacteria. In this way, there is no problem for the increase of the volume of the powdery wastes formed by the addition of inhibitor for the effect of oxidizable material. Further, heating upon solidification which is indispensable so far is no more necessary to simplify the facility and the operation. Furthermore, the solidification inhibiting material can be reduced stably and reliably under the same operation conditions even if the composition of the liquid wastes is charged or varied. (Kamimura, M.)

  15. A modified method to determine biomass concentration as COD in ...

    African Journals Online (AJOL)

    drinie

    2002-10-04

    Oct 4, 2002 ... standard volatile suspended solid (VSS) method. The proposed ... allowed the biomass determination in 1 μm size bacteria cultures that cannot be detected by the standard VSS method because cells are not retained by the ... indicates consumption of oxygen in receiving water bodies for the biochemical ...

  16. Estimation of suspended sediment concentration in rivers using acoustic methods.

    Science.gov (United States)

    Elçi, Sebnem; Aydin, Ramazan; Work, Paul A

    2009-12-01

    Acoustic Doppler current meters (ADV, ADCP, and ADP) are widely used in water systems to measure flow velocities and velocity profiles. Although these meters are designed for flow velocity measurements, they can also provide information defining the quantity of particulate matter in the water, after appropriate calibration. When an acoustic instrument is calibrated for a water system, no additional sensor is needed to measure suspended sediment concentration (SSC). This provides the simultaneous measurements of velocity and concentration required for most sediment transport studies. The performance of acoustic Doppler current meters for measuring SSC was investigated in different studies where signal-to-noise ratio (SNR) and suspended sediment concentration were related using different formulations. However, these studies were each limited to a single study site where neither the effect of particle size nor the effect of temperature was investigated. In this study, different parameters that affect the performance of an ADV for the prediction of SSC are investigated. In order to investigate the reliability of an ADV for SSC measurements in different environments, flow and SSC measurements were made in different streams located in the Aegean region of Turkey having different soil types. Soil samples were collected from all measuring stations and particle size analysis was conducted by mechanical means. Multivariate analysis was utilized to investigate the effect of soil type and water temperature on the measurements. Statistical analysis indicates that SNR readings ob tained from the ADV are affected by water temperature and particle size distribution of the soil, as expected, and a prediction model is presented relating SNR readings to SSC mea surements where both water temperature and sediment characteristics type are incorporated into the model. The coefficients of the suggested model were obtained using the multivariate anal ysis. Effect of high turbidity

  17. [Microbiological assay method for T-3761 concentration in body fluids].

    Science.gov (United States)

    Maehana, J; Kitayama, R; Matsumoto, Y; Kumano, K; Minami, S; Yasuda, T; Watanabe, Y; Narita, H

    1995-05-01

    A microbiological assay method for measurement of T-3761 and its stability in body fluids were investigated. The paper disc method proved suitable for this assay using Escherichia coli Kp as a test organism and commercially available heart infusion agar as a test medium. When using the paper disc method, lower detection limit of T-3761 was approximately 0.05 microgram/ml and 0.1 microgram/ml for 1/15M phosphate buffer (pH 7.0) and human serum, respectively. T-3761 in human serum and urine was stable under freezing -20 degrees C for at least 28 days.

  18. Combustible gas concentration control facility and operation method therefor

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Kazuhiro; Ando, Koji; Kinoshita, Shoichiro; Yamanari, Shozo; Moriya, Kimiaki; Karasawa, Hidetoshi

    1998-09-25

    The present invention provides a hydrogen gas-control facility by using a fuel battery-type combustible gas concentration reducing device as a countermeasure for controlling a hydrogen gas in a reactor container. Namely, a hydrogen electrode adsorb hydrogen by using an ion exchange membrane comprising hydrogen ions as a charge carrier. An air electrode adsorb oxygen in the air. A fuel battery converts recombining energy of hydrogen and oxygen to electric energy. Hydrogen in this case is supplied from an atmosphere in the container. Oxygen in this case is supplied from the air outside of the container. If hydrogen gas should be generated in the reactor, power generation of is performed by the fuel battery by using hydrogen gas, as a fuel, on the side of the hydrogen electrode of the fuel battery and using oxygen, as a fuel, in the air outside of the container on the side of the air electrode. Then, the hydrogen gas is consumed thereby controlling the hydrogen gas concentration in the container. Electric current generated in the fuel battery is used as an emergency power source for the countermeasure for a severe accident. (I.S.)

  19. A magnetic method to concentrate and trap biological targets

    KAUST Repository

    Li, Fuquan

    2012-11-01

    Magnetoresistive sensors in combination with magnetic particles have been used in biological applications due to, e.g., their small size and high sensitivity. A growing interest is to integrate magnetoresistive sensors with microchannels and electronics to fabricate devices that can perform complex analyses. A major task in such systems is to immobilize magnetic particles on top of the sensor surface, which is required to detect the particles\\' stray field. In the presented work, a bead concentrator, consisting of gold microstructures, at the bottom of a microchannel, is used to attract and move magnetic particles into a trap. The trap is made of a chamber with a gold microstructure underneath and is used to attract and immobilize a defined number of magnetic beads. In order to detect targets, two kinds of solutions were prepared; one containing only superparamagnetic particles, the other one containing beads with the protein Bovine serum albumin as the target and fluorescent markers. Due to the size difference between bare beads and beads with target, less magnetic beads were immobilized inside the volume chamber in case of magnetic beads with target as compared to bare magnetic beads. © 1965-2012 IEEE.

  20. Dish layouts analysis method for concentrative solar power plant.

    Science.gov (United States)

    Xu, Jinshan; Gan, Shaocong; Li, Song; Ruan, Zhongyuan; Chen, Shengyong; Wang, Yong; Gui, Changgui; Wan, Bin

    2016-01-01

    Designs leading to maximize the use of sun radiation of a given reflective area without increasing the expense on investment are important to solar power plants construction. We here provide a method that allows one to compute shade area at any given time as well as the total shading effect of a day. By establishing a local coordinate system with the origin at the apex of a parabolic dish and z -axis pointing to the sun, neighboring dishes only with [Formula: see text] would shade onto the dish when in tracking mode. This procedure reduces the required computational resources, simplifies the calculation and allows a quick search for the optimum layout by considering all aspects leading to optimized arrangement: aspect ratio, shifting and rotation. Computer simulations done with information on dish Stirling system as well as DNI data released from NREL, show that regular-spacing is not an optimal layout, shifting and rotating column by certain amount can bring more benefits.

  1. Comparison of two estimation methods for surface area concentration using number concentration and mass concentration of combustion-related ultrafine particles

    Science.gov (United States)

    Park, Ji Young; Raynor, Peter C.; Maynard, Andrew D.; Eberly, Lynn E.; Ramachandran, Gurumurthy

    Recent research has suggested that the adverse health effects caused by nanoparticles are associated with their surface area (SA) concentrations. In this study, SA was estimated in two ways using number and mass concentrations and compared with SA (SA meas) measured using a diffusion charger (DC). Aerosol measurements were made twice: once starting in October 2002 and again starting in December 2002 in Mysore, India in residences that used kerosene or liquefied petroleum gas (LPG) for cooking. Mass, number, and SA concentrations and size distributions by number were measured in each residence. The first estimation method (SA PSD) used the size distribution by number to estimate SA. The second method (SA INV) used a simple inversion scheme that incorporated number and mass concentrations while assuming a lognormal size distribution with a known geometrical standard deviation. SA PSD was, on average, 2.4 times greater (range = 1.6-3.4) than SA meas while SA INV was, on average, 6.0 times greater (range = 4.6-7.7) than SA meas. The logarithms of SA PSD and SA INV were found to be statistically significant predictors of the logarithm of SA meas. The study showed that particle number and mass concentration measurements can be used to estimate SA with a correction factor that ranges between 2 and 6.

  2. Comparative analysis of methods for concentrating venom from jellyfish Rhopilema esculentum Kishinouye

    Science.gov (United States)

    Li, Cuiping; Yu, Huahua; Feng, Jinhua; Chen, Xiaolin; Li, Pengcheng

    2009-02-01

    In this study, several methods were compared for the efficiency to concentrate venom from the tentacles of jellyfish Rhopilema esculentum Kishinouye. The results show that the methods using either freezing-dry or gel absorption to remove water to concentrate venom are not applicable due to the low concentration of the compounds dissolved. Although the recovery efficiency and the total venom obtained using the dialysis dehydration method are high, some proteins can be lost during the concentrating process. Comparing to the lyophilization method, ultrafiltration is a simple way to concentrate the compounds at high percentage but the hemolytic activities of the proteins obtained by ultrafiltration appear to be lower. Our results suggest that overall lyophilization is the best and recommended method to concentrate venom from the tentacles of jellyfish. It shows not only the high recovery efficiency for the venoms but high hemolytic activities as well.

  3. A new method for determining the formation energy of a vacancy in concentrated alloys

    International Nuclear Information System (INIS)

    Kinoshita, C.; Kitajima, S.; Eguchi, T.

    1978-01-01

    The disadvantages in the conventional method which determines the formation energy of a vacancy in concentrated alloys from their kinetic behavior during annealing after quenching are pointed out, and an alternative method for overcoming these disadvantages is proposed. (Auth.)

  4. Comparison of three methods for concentration of rotavirus from artificially spiked shellfish samples

    Directory of Open Access Journals (Sweden)

    Vysakh Mohan

    2014-07-01

    Full Text Available Background: Shellfish are a nutritious food source whose consumption and commercial value have risen dramatically worldwide. Shellfish being filter feeders concentrate particulate matters including microorganisms such as pathogenic bacteria and viruses and thus constitute a major public health concern. Effective preliminary sample treatment steps such as concentration of virus from shellfish are essential before RNA/DNA isolation for final PCR accuracy and reproducibility due to presence of PCR inhibitors in shellfish. Aim: The current study was done to compare three methods for concentration of rotavirus from shellfish samples. Materials and Methods: Shellfish samples artificially spiked with tenfold serial dilutions of known concentration of rotavirus were subjected to three different concentration methods namely; proteinase K treatment, precipitation with polyethylene glycol 8000 and use of lysis buffer. RNA was isolated from the concentrated samples using phenol chloroform method. Rota viral RNA was detected using RT-PCR. Results: Concentration of virus using proteinase K and lysis buffer yielded better result than concentration by PEG 8000 in samples with lowest concentration of virus. Among these two methods proteinase K treatment was superior as it showed better amplification of the highest dilution (107 used. Conclusion: Treatment with proteinase K was better than other two methods as it could detect the viral RNA in all three tenfold serial dilutions.

  5. A method for estimation of plasma albumin concentration from the buffering properties of whole blood

    DEFF Research Database (Denmark)

    Rees, Stephen Edward; Diemer, Tue; Kristensen, Søren Risom

    2012-01-01

    measurements of acid-base and oxygenation status. This article presents and evaluates a new method for doing so. MATERIALS AND METHODS: The mathematical method for estimating plasma albumin concentration is described. To evaluate the method at numerous albumin concentrations, blood from 19 healthy subjects......PURPOSE: Hypoalbuminemia is strongly associated with poor clinical outcome. Albumin is usually measured at the central laboratory rather than point of care, but in principle, information exists in the buffering properties of whole blood to estimate plasma albumin concentration from point of care...

  6. Non-Aqueous Titration Method for Determining Suppressor Concentration in the MCU Next Generation Solvent (NGS)

    International Nuclear Information System (INIS)

    Taylor-Pashow, Kathryn M. L.; Jones, Daniel H.

    2017-01-01

    A non-aqueous titration method has been used for quantifying the suppressor concentration in the MCU solvent hold tank (SHT) monthly samples since the Next Generation Solvent (NGS) was implemented in 2013. The titration method measures the concentration of the NGS suppressor (TiDG) as well as the residual tri-n-octylamine (TOA) that is a carryover from the previous solvent. As the TOA concentration has decreased over time, it has become difficult to resolve the TiDG equivalence point as the TOA equivalence point has moved closer. In recent samples, the TiDG equivalence point could not be resolved, and therefore, the TiDG concentration was determined by subtracting the TOA concentration as measured by semi-volatile organic analysis (SVOA) from the total base concentration as measured by titration. In order to improve the titration method so that the TiDG concentration can be measured directly, without the need for the SVOA data, a new method has been developed that involves spiking of the sample with additional TOA to further separate the two equivalence points in the titration. This method has been demonstrated on four recent SHT samples and comparison to results obtained using the SVOA TOA subtraction method shows good agreement. Therefore, it is recommended that the titration procedure be revised to include the TOA spike addition, and this to become the primary method for quantifying the TiDG.

  7. Non-Aqueous Titration Method for Determining Suppressor Concentration in the MCU Next Generation Solvent (NGS)

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, Kathryn M. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jones, Daniel H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-10-23

    A non-aqueous titration method has been used for quantifying the suppressor concentration in the MCU solvent hold tank (SHT) monthly samples since the Next Generation Solvent (NGS) was implemented in 2013. The titration method measures the concentration of the NGS suppressor (TiDG) as well as the residual tri-n-octylamine (TOA) that is a carryover from the previous solvent. As the TOA concentration has decreased over time, it has become difficult to resolve the TiDG equivalence point as the TOA equivalence point has moved closer. In recent samples, the TiDG equivalence point could not be resolved, and therefore, the TiDG concentration was determined by subtracting the TOA concentration as measured by semi-volatile organic analysis (SVOA) from the total base concentration as measured by titration. In order to improve the titration method so that the TiDG concentration can be measured directly, without the need for the SVOA data, a new method has been developed that involves spiking of the sample with additional TOA to further separate the two equivalence points in the titration. This method has been demonstrated on four recent SHT samples and comparison to results obtained using the SVOA TOA subtraction method shows good agreement. Therefore, it is recommended that the titration procedure be revised to include the TOA spike addition, and this to become the primary method for quantifying the TiDG.

  8. A method for the control of alumina concentration in aluminum reduction cells

    Directory of Open Access Journals (Sweden)

    Jens G. Balchen

    1992-01-01

    Full Text Available The paper presents a new method for the control of the concentration of the alumina in electrolysis cells for the production of aluminium. The method is based upon the well known fact that apparent resistivity of the cell is a function of the alumina concentration so that the resistivity has the lowest value around the concentration of three per cent and increases in both directions. The method uses the cross correlation between a perturbation of the feed flow of alumina into the cell and the resulting response in measured voltage across the cell. The cross-correlation is proportional to the slope of the resistivity against concentration curve, making it possible to control the alumina flow, to achieve a desired slope. The method has much in common with other methods presently in use which require a much more complicated computation scheme.

  9. LC/ESI-MS/MS method for determination of salivary eicosapentaenoic acid concentration to arachidonic acid concentration ratio.

    Science.gov (United States)

    Ogawa, Shoujiro; Tomaru, Koki; Matsumoto, Nagisa; Watanabe, Shui; Higashi, Tatsuya

    2016-01-01

    A simple liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) method for determination of the eicosapentaenoic acid (EPA) concentration to arachidonic acid (AA) concentration ratio in human saliva has been developed. The EPA/AA ratio in serum or plasma is widely recognized as a useful indicator in identifying the risk of cardiovascular disease, especially atherosclerosis. The salivary EPA/AA ratio is expected to be a convenient alternative to the serum or plasma EPA/AA ratio, because saliva offers the advantages of easy and noninvasive sampling. The saliva was deproteinized with acetonitrile, purified using an Oasis HLB cartridge, and derivatized with 1-[(4-dimethylaminophenyl)carbonyl]piperazine (DAPPZ). The derivatized EPA and AA were subjected to LC/ESI-MS/MS, and the EPA/AA ratio was determined using the selected reaction monitoring mode. The DAPPZ-derivatization increased the ESI sensitivity by 100- and 300-fold for EPA and AA, respectively, and enabled the detection of trace fatty acids in saliva using a 200 μL sample. The assay reproducibility was satisfactory (relative standard deviation, <5.0%). The method was successfully applied to the measurement of the salivary EPA/AA ratios of healthy Japanese subjects and their changes owing to the supplementation of EPA. Copyright © 2015 John Wiley & Sons, Ltd.

  10. Description of a double centrifugation tube method for concentrating canine platelets

    OpenAIRE

    Perazzi, Anna; Busetto, Roberto; Martinello, Tiziana; Drigo, Michele; Pasotto, Daniela; Cian, Francesco; Patruno, Marco; Iacopetti, Ilaria

    2013-01-01

    Background To evaluate the efficiency of platelet-rich plasma preparations by means of a double centrifugation tube method to obtain platelet-rich canine plasma at a concentration at least 4 times higher than the baseline value and a concentration of white blood cells not exceeding twice the reference range. A complete blood count was carried out for each sample and each concentrate. Whole blood samples were collected from 12 clinically healthy dogs (consenting blood donors). Blood was proces...

  11. Collaborative validation of a rapid method for efficient virus concentration in bottled water

    DEFF Research Database (Denmark)

    Schultz, Anna Charlotte; Perelle, Sylvie; Di Pasquale, Simona

    2011-01-01

    Enteric viruses, including norovirus (NoV) and hepatitis A virus (HAV), have emerged as a major cause of waterborne outbreaks worldwide. Due to their low infectious doses and low concentrations in water samples, an efficient and rapid virus concentration method is required for routine control. Th...

  12. Survival data analyses in ecotoxicology: critical effect concentrations, methods and models. What should we use?

    Science.gov (United States)

    Forfait-Dubuc, Carole; Charles, Sandrine; Billoir, Elise; Delignette-Muller, Marie Laure

    2012-05-01

    In ecotoxicology, critical effect concentrations are the most common indicators to quantitatively assess risks for species exposed to contaminants. Three types of critical effect concentrations are classically used: lowest/ no observed effect concentration (LOEC/NOEC), LC( x) (x% lethal concentration) and NEC (no effect concentration). In this article, for each of these three types of critical effect concentration, we compared methods or models used for their estimation and proposed one as the most appropriate. We then compared these critical effect concentrations to each other. For that, we used nine survival data sets corresponding to D. magna exposition to nine different contaminants, for which the time-course of the response was monitored. Our results showed that: (i) LOEC/NOEC values at day 21 were method-dependent, and that the Cochran-Armitage test with a step-down procedure appeared to be the most protective for the environment; (ii) all tested concentration-response models we compared gave close values of LC50 at day 21, nevertheless the Weibull model had the lowest global mean deviance; (iii) a simple threshold NEC-model both concentration and time dependent more completely described whole data (i.e. all timepoints) and enabled a precise estimation of the NEC. We then compared the three critical effect concentrations and argued that the use of the NEC might be a good option for environmental risk assessment.

  13. Comparing concentration methods: parasitrap® versus Kato-Katz for ...

    African Journals Online (AJOL)

    Comparing concentration methods: parasitrap® versus Kato-Katz for studying the prevalence of Helminths in Bengo province, Angola. Clara Mirante, Isabel Clemente, Graciette Zambu, Catarina Alexandre, Teresa Ganga, Carlos Mayer, Miguel Brito ...

  14. Accurate mass replacement method for the sediment concentration measurement with a constant volume container

    Science.gov (United States)

    Ban, Yunyun; Chen, Tianqin; Yan, Jun; Lei, Tingwu

    2017-04-01

    The measurement of sediment concentration in water is of great importance in soil erosion research and soil and water loss monitoring systems. The traditional weighing method has long been the foundation of all the other measuring methods and instrument calibration. The development of a new method to replace the traditional oven-drying method is of interest in research and practice for the quick and efficient measurement of sediment concentration, especially field measurements. A new method is advanced in this study for accurately measuring the sediment concentration based on the accurate measurement of the mass of the sediment-water mixture in the confined constant volume container (CVC). A sediment-laden water sample is put into the CVC to determine its mass before the CVC is filled with water and weighed again for the total mass of the water and sediments in the container. The known volume of the CVC, the mass of sediment-laden water, and sediment particle density are used to calculate the mass of water, which is replaced by sediments, therefore sediment concentration of the sample is calculated. The influence of water temperature was corrected by measuring water density to determine the temperature of water before measurements were conducted. The CVC was used to eliminate the surface tension effect so as to obtain the accurate volume of water and sediment mixture. Experimental results showed that the method was capable of measuring the sediment concentration from 0.5 up to 1200 kg m-3. A good liner relationship existed between the designed and measured sediment concentrations with all the coefficients of determination greater than 0.999 and the averaged relative error less than 0.2%. All of these seem to indicate that the new method is capable of measuring a full range of sediment concentration above 0.5 kg m-3 to replace the traditional oven-drying method as a standard method for evaluating and calibrating other methods.

  15. Determination of U-chain concentration in NaI(Tl) scintillator by delayed coincidence method

    CERN Document Server

    Umehara, S; Koori, N; Kudomi, N; Kume, K; Kuramoto, H; Nakayama, S; Shimojo, T; Takahisa, K; Tsubakida, R; Tsujimoto, Y; Yoshida, S

    2002-01-01

    We have accurately determined U-chain concentration in a detector by means of the beta-alpha delayed coincidence method. This method can measure the radioactivity of the order of 10 sup - sup 7 Bq/kg. It corresponds to the concentration of the order of 0.01 ppt under the assumption that the U-chain is in the secular radioactive equilibrium, by a signal-to-noise ratio of one to one.

  16. Chromatographic method of measurement of helium concentration in underground waters for dating in hydrological questions

    International Nuclear Information System (INIS)

    Najman, J.

    2008-04-01

    Research methods which use natural environmental indicators are widely applied in hydrology. Different concentrations of indicators and their isotopic components in ground waters allow to determine the genesis of waters and are valuable source of information about the water flow dynamics. One of the significant indicator is helium. The concentration of 4 He (helium) in ground water is a fine indicator in water dating in a range from a hundreds to millions of years (Aeschbach-Hertig i in., 1999; Andrews i in., 1989; Castro i in., 2000; Zuber i in., 2007). 4 He is also used for dating young waters of age about 10 years (Solomon i in., 1996). Thesis consist the description of elaborated in IFJ PAN in Krakow chromatographic measurement method of helium concentration in ground waters in aim of dating. Chapter 1 contain short introduction about ground water dating and chapter 2 description of helium property and chosen applications of helium for example in technology and earthquake predictions. Helium sources in ground waters are described in chapter 3. Helium concentration in water after infiltration (originated from atmosphere) to the ground water system depends mainly on the helium concentration coming from the equilibration with the atmosphere increased by additional concentration from '' excess air ''. With the increasing resistance time of ground water during the flow, radiogenic, non-atmospheric component of helium dissolves also in water. In chapter 4 two measurement methods of helium concentration in ground waters were introduced: mass spectrometric and gas chromatographic method. Detailed description of elaborated chromatographic measurement method of helium concentration in ground water contain chapter 5. To verify developed method the concentration of helium in ground waters from the regions of Krakow and Busko Zdroj were measured. For this waters the concentrations of helium are known from the earlier mass spectrometric measurements. The results of

  17. Quality assessment of platelet concentrates prepared by platelet rich plasma-platelet concentrate, buffy coat poor-platelet concentrate (BC-PC and apheresis-PC methods

    Directory of Open Access Journals (Sweden)

    Singh Ravindra

    2009-01-01

    Full Text Available Background: Platelet rich plasma-platelet concentrate (PRP-PC, buffy coat poor-platelet concentrate (BC-PC, and apheresis-PC were prepared and their quality parameters were assessed. Study Design: In this study, the following platelet products were prepared: from random donor platelets (i platelet rich plasma - platelet concentrate (PRP-PC, and (ii buffy coat poor- platelet concentrate (BC-PC and (iii single donor platelets (apheresis-PC by different methods. Their quality was assessed using the following parameters: swirling, volume of the platelet concentrate, platelet count, WBC count and pH. Results: A total of 146 platelet concentrates (64 of PRP-PC, 62 of BC-PC and 20 of apheresis-PC were enrolled in this study. The mean volume of PRP-PC, BC-PC and apheresis-PC was 62.30±22.68 ml, 68.81±22.95 ml and 214.05±9.91 ml and ranged from 22-135 ml, 32-133 ml and 200-251 ml respectively. The mean platelet count of PRP-PC, BC-PC and apheresis-PC was 7.6±2.97 x 1010/unit, 7.3±2.98 x 1010/unit and 4.13±1.32 x 1011/unit and ranged from 3.2-16.2 x 1010/unit, 0.6-16.4 x 1010/unit and 1.22-8.9 x 1011/unit respectively. The mean WBC count in PRP-PC (n = 10, BC-PC (n = 10 and apheresis-PC (n = 6 units was 4.05±0.48 x 107/unit, 2.08±0.39 x 107/unit and 4.8±0.8 x 106/unit and ranged from 3.4 -4.77 x 107/unit, 1.6-2.7 x 107/unit and 3.2 - 5.2 x 106/unit respectively. A total of 26 units were analyzed for pH changes. Out of these units, 10 each were PRP-PC and BC-PC and 6 units were apheresis-PC. Their mean pH was 6.7±0.26 (mean±SD and ranged from 6.5 - 7.0 and no difference was observed among all three types of platelet concentrate. Conclusion: PRP-PC and BC-PC units were comparable in terms of swirling, platelet count per unit and pH. As expected, we found WBC contamination to be less in BC-PC than PRP-PC units. Variation in volume was more in BC-PC than PRP-PC units and this suggests that further standardization is required for preparation of BC

  18. Radon concentrations in groundwater in Busan measured with a liquid scintillation counter method.

    Science.gov (United States)

    Cho, J S; Ahn, J K; Kim, H-Ch; Lee, D W

    2004-01-01

    In this paper, we present the first measurement of radon concentrations in drinking groundwater from private and public deep-bored wells located in the south-eastern area of Korea. The measurements were carried out on 439 samples by using a liquid scintillation method. The results show that the radon concentrations of the samples range from 0 to about 300 Bq l(-1). We find that Sasang ward shows the highest median value of radon concentration among 13 different wards, while Jung ward has the lowest. We find that the radon concentrations are highly dependent on the type of geological rock aquifers.

  19. A method for addressing differences in concentrations of fipronil and three degradates obtained by two different laboratory methods

    Science.gov (United States)

    Crawford, Charles G.; Martin, Jeffrey D.

    2017-07-21

    In October 2012, the U.S. Geological Survey (USGS) began measuring the concentration of the pesticide fipronil and three of its degradates (desulfinylfipronil, fipronil sulfide, and fipronil sulfone) by a new laboratory method using direct aqueous-injection liquid chromatography tandem mass spectrometry (DAI LC–MS/MS). This method replaced the previous method—in use since 2002—that used gas chromatography/mass spectrometry (GC/MS). The performance of the two methods is not comparable for fipronil and the three degradates. Concentrations of these four chemical compounds determined by the DAI LC–MS/MS method are substantially lower than the GC/MS method. A method was developed to correct for the difference in concentrations obtained by the two laboratory methods based on a methods comparison field study done in 2012. Environmental and field matrix spike samples to be analyzed by both methods from 48 stream sites from across the United States were sampled approximately three times each for this study. These data were used to develop a relation between the two laboratory methods for each compound using regression analysis. The relations were used to calibrate data obtained by the older method to the new method in order to remove any biases attributable to differences in the methods. The coefficients of the equations obtained from the regressions were used to calibrate over 16,600 observations of fipronil, as well as the three degradates determined by the GC/MS method retrieved from the USGS National Water Information System. The calibrated values were then compared to over 7,800 observations of fipronil and to the three degradates determined by the DAI LC–MS/MS method also retrieved from the National Water Information System. The original and calibrated values from the GC/MS method, along with measures of uncertainty in the calibrated values and the original values from the DAI LC–MS/MS method, are provided in an accompanying data release.

  20. Fixed Nadir Focus Concentrated Solar Power Applying Reflective Array Tracking Method

    Science.gov (United States)

    Setiawan, B.; DAMayanti, A. M.; Murdani, A.; Habibi, I. I. A.; Wakidah, R. N.

    2018-04-01

    The Sun is one of the most potential renewable energy develoPMent to be utilized, one of its utilization is for solar thermal concentrators, CSP (Concentrated Solar Power). In CSP energy conversion, the concentrator is as moving the object by tracking the sunlight to reach the focus point. This method need quite energy consumption, because the unit of the concentrators has considerable weight, and use large CSP, means the existence of the usage unit will appear to be wider and heavier. The addition of weight and width of the unit will increase the torque to drive the concentrator and hold the wind gusts. One method to reduce energy consumption is direct the sunlight by the reflective array to nadir through CSP with Reflective Fresnel Lens concentrator. The focus will be below the nadir direction, and the position of concentrator will be fixed position even the angle of the sun’s elevation changes from morning to afternoon. So, the energy concentrated maximally, because it has been protected from wind gusts. And then, the possibility of dAMage and changes in focus construction will not occur. The research study and simulation of the reflective array (mechanical method) will show the reflective angle movement. The distance between reflectors and their angle are controlled by mechatronics. From the simulation using fresnel 1m2, and efficiency of solar energy is 60.88%. In restriction, the intensity of sunlight at the tropical circles 1KW/peak, from 6 AM until 6 PM.

  1. Concentration gradient driven molecular dynamics: a new method for simulations of membrane permeation and separation.

    Science.gov (United States)

    Ozcan, Aydin; Perego, Claudio; Salvalaglio, Matteo; Parrinello, Michele; Yazaydin, Ozgur

    2017-05-01

    In this study, we introduce a new non-equilibrium molecular dynamics simulation method to perform simulations of concentration driven membrane permeation processes. The methodology is based on the application of a non-conservative bias force controlling the concentration of species at the inlet and outlet of a membrane. We demonstrate our method for pure methane, ethane and ethylene permeation and for ethane/ethylene separation through a flexible ZIF-8 membrane. Results show that a stationary concentration gradient is maintained across the membrane, realistically simulating an out-of-equilibrium diffusive process, and the computed permeabilities and selectivity are in good agreement with experimental results.

  2. Continuous measurement of the radon concentration in water using electret ion chamber method

    International Nuclear Information System (INIS)

    Dua, S.K.; Hopke, P.K.

    1992-10-01

    A radon concentration of 300 pCi/L has been proposed by the US Environmental Protection Agency as a limit for radon dissolved in municipal drinking water supplies. There is therefore a need for a continuous monitor to insure that the daily average concentration does not exceed this limit. In order to calibrate the system, varying concentrations of radon in water have been generated by bubbling radon laden air through a dynamic flowthrough water system. The value of steady state concentration of radon in water from this system depends on the concentration of radon in air, the air bubbling rate, and the water flow rate. The measurement system has been designed and tested using a 1 L volume electret ion chamber to determine the radon in water. In this dynamic method, water flows directly through the electret ion chamber. Radon is released to the air and measured with the electret. A flow of air is maintained through the chamber to prevent the build-up of high radon concentrations and too rapid discharge of the electret. It was found that the system worked well when the air flow was induced by the application of suction. The concentration in the water was calculated from the measured concentration in air and water and air flow rates. Preliminary results suggest that the method has sufficient sensitivity to measure concentrations of radon in water with acceptable accuracy and precision

  3. Evaluation of single and double centrifugation tube methods for concentrating equine platelets.

    Science.gov (United States)

    Argüelles, D; Carmona, J U; Pastor, J; Iborra, A; Viñals, L; Martínez, P; Bach, E; Prades, M

    2006-10-01

    The aim of this study was to evaluate single and double centrifugation tube methods for concentrating equine platelets. Whole blood samples were collected from clinically normal horses and processed by use of single and double centrifugation tube methods to obtain four platelet concentrates (PCs): PC-A, PC-B, PC-C, and PC-D, which were analyzed using a flow cytometry hematology system for hemogram and additional platelet parameters (mean platelet volume, platelet distribution width, mean platelet component concentration, mean platelet component distribution width). Concentrations of transforming growth factor beta 1 (TGF-beta(1)) were determined in all the samples. Platelet concentrations for PC-A, PC-B, PC-C, and PC-D were 45%, 44%, 71%, and 21% higher, respectively, compared to the same values for citrated whole blood samples. TGF-beta(1) concentrations for PC-A, PC-B, PC-C, and PC-D were 38%, 44%, 44%, and 37% higher, respectively, compared to citrated whole blood sample values. In conclusion, the single and double centrifugation tube methods are reliable methods for concentrating equine platelets and for obtaining potentially therapeutic TGF-beta(1) levels.

  4. Methods to Concentrate Proteins for Protein Isolation, Proteomic, and Peptidomic Evaluation.

    Science.gov (United States)

    Goldring, J P Dean

    2015-01-01

    In protein isolation, proteomic, or peptidomic procedures, protein solutions are often concentrated to remove solvents and undesirable molecules, to separate protein fractions or to increase protein concentrations. Proteins can be concentrated by precipitation from solution with ammonium sulfate, polyethylene glycol, organic solvent, trichloroacetic acid, potassium chloride/sodium dodecyl sulfate, and three-phase partitioning. Solvents can be removed by passage through a semipermeable barrier where protein solutions are forced against the barrier in a centrifuge tube or with increased pressure concentrating protein in the remaining solution. The semipermeable barrier can be surrounded by a hygroscopic reagent to draw the solvent across the membrane. Proteins can be concentrated by freeze-drying (lyophilization). All these methods to concentrate proteins are discussed.

  5. A high-accuracy measurement method of glucose concentration in interstitial fluid based on microdialysis

    Science.gov (United States)

    Li, Dachao; Xu, Qingmei; Liu, Yu; Wang, Ridong; Xu, Kexin; Yu, Haixia

    2017-11-01

    A high-accuracy microdialysis method that can provide the reference values of glucose concentration in interstitial fluid for the accurate evaluation of non-invasive and minimally invasive continuous glucose monitoring is reported in this study. The parameters of the microdialysis process were firstly optimized by testing and analyzing three main factors that impact microdialysis recovery, including the perfusion rate, temperature, and glucose concentration in the area surrounding the microdialysis probe. The precision of the optimized microdialysis method was then determined in a simulation system that was designed and established in this study to simulate variations in continuous glucose concentration in the human body. Finally, the microdialysis method was tested for in vivo interstitial glucose concentration measurement.

  6. Standard Test Method for Electrical Performance of Concentrator Terrestrial Photovoltaic Modules and Systems Under Natural Sunlight

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This test method covers the determination of the electrical performance of photovoltaic concentrator modules and systems under natural sunlight using a normal incidence pyrheliometer. 1.2 The test method is limited to module assemblies and systems where the geometric concentration ratio specified by the manufacturer is greater than 5. 1.3 This test method applies to concentrators that use passive cooling where the cell temperature is related to the air temperature. 1.4 Measurements under a variety of conditions are allowed; results are reported under a select set of concentrator reporting conditions to facilitate comparison of results. 1.5 This test method applies only to concentrator terrestrial modules and systems. 1.6 This test method assumes that the module or system electrical performance characteristics do not change during the period of test. 1.7 The performance rating determined by this test method applies only at the period of the test, and implies no past or future performance level. 1.8...

  7. A Toxocara cati eggs concentration method from cats' faeces, for experimental and diagnostic purposes.

    Science.gov (United States)

    Cardillo, N; Sommerfelt, I; Fariña, F; Pasqualetti, M; Pérez, M; Ercole, M; Rosa, A; Ribicich, M

    2014-09-01

    Toxocariosis is a zoonotic parasite infection worldwide distributed, now considered a neglected disease associated to poverty. For experimental infection in animals and to develop the diagnosis in humans it is necessary to obtain large number of Toxocara spp. larval eggs. Toxocara cati eggs recovered percentage from faeces of infected cats was determined employing a novel egg concentration method. The McMaster egg counting technique and the concentration method were applied on 20 positive cats' sample faeces obtained from naturally infected cats. The mean percentage of eggs recovered by the concentration method was 24.37% higher than the count obtained by McMaster egg counting technique. The main advantage of this method is that it can be obtained a small final volume with a high number of recovered eggs and a good quality inoculum for experimental and diagnostic purposes. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Direct concentration and viability measurement of yeast in corn mash using a novel imaging cytometry method.

    Science.gov (United States)

    Chan, Leo L; Lyettefi, Emily J; Pirani, Alnoor; Smith, Tim; Qiu, Jean; Lin, Bo

    2011-08-01

    Worldwide awareness of fossil-fuel depletion and global warming has been increasing over the last 30 years. Numerous countries, including the USA and Brazil, have introduced large-scale industrial fermentation facilities for bioethanol, biobutanol, or biodiesel production. Most of these biofuel facilities perform fermentation using standard baker's yeasts that ferment sugar present in corn mash, sugar cane, or other glucose media. In research and development in the biofuel industry, selection of yeast strains (for higher ethanol tolerance) and fermentation conditions (yeast concentration, temperature, pH, nutrients, etc.) can be studied to optimize fermentation performance. Yeast viability measurement is needed to identify higher ethanol-tolerant yeast strains, which may prolong the fermentation cycle and increase biofuel output. In addition, yeast concentration may be optimized to improve fermentation performance. Therefore, it is important to develop a simple method for concentration and viability measurement of fermenting yeast. In this work, we demonstrate an imaging cytometry method for concentration and viability measurements of yeast in corn mash directly from operating fermenters. It employs an automated cell counter, a dilution buffer, and staining solution from Nexcelom Bioscience to perform enumeration. The proposed method enables specific fluorescence detection of viable and nonviable yeasts, which can generate precise results for concentration and viability of yeast in corn mash. This method can provide an essential tool for research and development in the biofuel industry and may be incorporated into manufacturing to monitor yeast concentration and viability efficiently during the fermentation process.

  9. Description of a double centrifugation tube method for concentrating canine platelets.

    Science.gov (United States)

    Perazzi, Anna; Busetto, Roberto; Martinello, Tiziana; Drigo, Michele; Pasotto, Daniela; Cian, Francesco; Patruno, Marco; Iacopetti, Ilaria

    2013-07-22

    To evaluate the efficiency of platelet-rich plasma preparations by means of a double centrifugation tube method to obtain platelet-rich canine plasma at a concentration at least 4 times higher than the baseline value and a concentration of white blood cells not exceeding twice the reference range. A complete blood count was carried out for each sample and each concentrate. Whole blood samples were collected from 12 clinically healthy dogs (consenting blood donors). Blood was processed by a double centrifugation tube method to obtain platelet concentrates, which were then analyzed by a flow cytometry haematology system for haemogram. Platelet concentration and white blood cell count were determined in all samples. Platelet concentration at least 4 times higher than the baseline value and a white blood cell count not exceeding twice the reference range were obtained respectively in 10 cases out of 12 (83.3%) and 11 cases out of 12 (91.6%). This double centrifugation tube method is a relatively simple and inexpensive method for obtaining platelet-rich canine plasma, potentially available for therapeutic use to improve the healing process.

  10. Methods to homogenize electrochemical concentration cell (ECC) ozonesonde measurements across changes in sensing solution concentration or ozonesonde manufacturer

    Science.gov (United States)

    Deshler, Terry; Stübi, Rene; Schmidlin, Francis J.; Mercer, Jennifer L.; Smit, Herman G. J.; Johnson, Bryan J.; Kivi, Rigel; Nardi, Bruno

    2017-06-01

    function can be characterized as a simple ratio of the less sensitive to the more sensitive method. This ratio is 0.96 for both solution concentration and ozonesonde type. The ratios differ at pressures < 30 hPa such that OZ0. 5%/OZ1. 0 % = 0. 90 + 0. 041 ṡ log10(p) and OZSciencePump/OZENSCI = 0. 764 + 0. 133 ṡ log10(p) for p in units of hPa. For the manufacturer-recommended solution concentrations the dispersion of the ratio (SP-1.0 / EN-0.5 %), while significant, is generally within 3 % and centered near 1.0, such that no changes are recommended. For stations which have used multiple ozonesonde types with solution concentrations different from the WMO's and manufacturer's recommendations, this work suggests that a reasonably homogeneous data set can be created if the quantitative relationships specified above are applied to the non-standard measurements. This result is illustrated here in an application to the Nairobi data set.

  11. Methods to homogenize electrochemical concentration cell (ECC ozonesonde measurements across changes in sensing solution concentration or ozonesonde manufacturer

    Directory of Open Access Journals (Sweden)

    T. Deshler

    2017-06-01

    ≥  30 hPa, and thus the transfer function can be characterized as a simple ratio of the less sensitive to the more sensitive method. This ratio is 0.96 for both solution concentration and ozonesonde type. The ratios differ at pressures < 30 hPa such that OZ0. 5%/OZ1. 0 % =  0. 90 + 0. 041 ⋅ log10(p and OZSciencePump/OZENSCI =  0. 764 + 0. 133 ⋅ log10(p for p in units of hPa. For the manufacturer-recommended solution concentrations the dispersion of the ratio (SP-1.0 / EN-0.5 %, while significant, is generally within 3 % and centered near 1.0, such that no changes are recommended. For stations which have used multiple ozonesonde types with solution concentrations different from the WMO's and manufacturer's recommendations, this work suggests that a reasonably homogeneous data set can be created if the quantitative relationships specified above are applied to the non-standard measurements. This result is illustrated here in an application to the Nairobi data set.

  12. A new modelling method and unified code with MCRT for concentrating solar collectors and its applications

    International Nuclear Information System (INIS)

    Cheng, Z.D.; He, Y.L.; Cui, F.Q.

    2013-01-01

    Highlights: ► A general-purpose method or design/simulation tool needs to be developed for CSCs. ► A new modelling method and homemade unified code with MCRT are presented. ► The photo-thermal conversion processes in three typical CSCs were analyzed. ► The results show that the proposed method and model are feasible and reliable. -- Abstract: The main objective of the present work is to develop a general-purpose numerical method for improving design/simulation tools for the concentrating solar collectors (CSCs) of concentrated solar power (CSP) systems. A new modelling method and homemade unified code with the Monte Carlo Ray-Trace (MCRT) method for the CSCs are presented firstly. The details of the new designing method and homemade unified code with MCRT for numerical investigations on solar concentrating and collecting characteristics of the CSCs are introduced. Three coordinate systems are used in the MCRT program and can be totally independent from each other. Solar radiation in participating medium and/or non-participating medium can be taken into account simultaneously or dividedly in the simulation. The criteria of data processing and method/code checking are also proposed in detail. Finally the proposed method and code are applied to simulate and analyze the involuted photo-thermal conversion processes in three typical CSCs. The results show that the proposed method and model are reliable to simulate various types of CSCs.

  13. Effects of protein and phosphate buffer concentrations on thermal denaturation of lysozyme analyzed by isoconversional method.

    Science.gov (United States)

    Cao, X M; Tian, Y; Wang, Z Y; Liu, Y W; Wang, C X

    2016-07-03

    Thermal denaturation of lysozymes was studied as a function of protein concentration, phosphate buffer concentration, and scan rate using differential scanning calorimetry (DSC), which was then analyzed by the isoconversional method. The results showed that lysozyme thermal denaturation was only slightly affected by the protein concentration and scan rate. When the protein concentration and scan rate increased, the denaturation temperature (Tm) also increased accordingly. On the contrary, the Tm decreased with the increase of phosphate buffer concentration. The denaturation process of lysozymes was accelatated and the thermal stability was reduced with the increase of phosphate concentration. One part of degeneration process was not reversible where the aggregation occurred. The other part was reversible. The apparent activation energy (Ea) was computed by the isoconversional method. It decreased with the increase of the conversion ratio (α). The observed denaturation process could not be described by a simple reaction mechanism. It was not a process involving 2 standard reversible states, but a multi-step process. The new opportunities for investigating the kinetics process of protein denaturation can be supplied by this novel isoconversional method.

  14. A new method for rapid determination of carbohydrate and total carbon concentrations using UV spectrophotometry.

    Science.gov (United States)

    Albalasmeh, Ammar A; Berhe, Asmeret Asefaw; Ghezzehei, Teamrat A

    2013-09-12

    A new UV spectrophotometry based method for determining the concentration and carbon content of carbohydrate solution was developed. This method depends on the inherent UV absorption potential of hydrolysis byproducts of carbohydrates formed by reaction with concentrated sulfuric acid (furfural derivatives). The proposed method is a major improvement over the widely used Phenol-Sulfuric Acid method developed by DuBois, Gilles, Hamilton, Rebers, and Smith (1956). In the old method, furfural is allowed to develop color by reaction with phenol and its concentration is detected by visible light absorption. Here we present a method that eliminates the coloration step and avoids the health and environmental hazards associated with phenol use. In addition, avoidance of this step was shown to improve measurement accuracy while significantly reducing waiting time prior to light absorption reading. The carbohydrates for which concentrations and carbon content can be reliably estimated with this new rapid Sulfuric Acid-UV technique include: monosaccharides, disaccharides and polysaccharides with very high molecular weight. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. An enhanced-gravity method to recover ultra-fine coal from tailings: Falcon concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Filiz Oruc; Selcuk Ozgen; Eyup Sabah [Afyon Kocatepe University, Afyonkarahisar (Turkey). Department of Mining Engineering

    2010-09-15

    The Falcon concentrator is an enhanced-gravity separator used for the concentration of fine and ultra-fine minerals. This study was conducted to evaluate the effects of different process variables on the performance of the Falcon SB-40 concentrator for beneficiation of tailings to recover ultra-fine coal. Various operating and design conditions such as bowl speed (G force), water pressure, pulp solid ratio and pulp feed rate were investigated. A hydrocyclone was used for pre-enrichment with the Falcon concentrator. Operation parameters of the hydrocyclone, namely feed solids, inlet pressure, vortex finder and apex diameters were investigated. In order to produce fine coal concentrates, regression equations were derived by applying the least squares method using Minitab 15 software. Response functions were produced for the ash content and the recovery of the clean coal concentrates for the performance of the hydrocyclone and Falcon concentrator under different operating conditions. Predicted values were found with the experimental values giving R{sup 2} values of between 0.73 and 0.58 for ash content and between 0.65 and 0.39 for recovery of the clean coal. It was shown that under optimized conditions the Falcon concentrator can produce a clean coal with an ash value of 36% from a feed coal of about 66% ash. 19 refs., 7 figs., 5 tabs.

  16. Method of estimating changes in vapor concentrations continuously generated from two-component organic solvents.

    Science.gov (United States)

    Hori, Hajime; Ishidao, Toru; Ishimatsu, Sumiyo

    2010-12-01

    We measured vapor concentrations continuously evaporated from two-component organic solvents in a reservoir and proposed a method to estimate and predict the evaporation rate or generated vapor concentrations. Two kinds of organic solvents were put into a small reservoir made of glass (3 cm in diameter and 3 cm high) that was installed in a cylindrical glass vessel (10 cm in diameter and 15 cm high). Air was introduced into the glass vessel at a flow rate of 150 ml/min, and the generated vapor concentrations were intermittently monitored for up to 5 hours with a gas chromatograph equipped with a flame ionization detector. The solvent systems tested in this study were the methanoltoluene system and the ethyl acetate-toluene system. The vapor concentrations of the more volatile component, that is, methanol in the methanol-toluene system and ethyl acetate in the ethyl acetate-toluene system, were high at first, and then decreased with time. On the other hand, the concentrations of the less volatile component were low at first, and then increased with time. A model for estimating multicomponent organic vapor concentrations was developed, based on a theory of vapor-liquid equilibria and a theory of the mass transfer rate, and estimated values were compared with experimental ones. The estimated vapor concentrations were in relatively good agreement with the experimental ones. The results suggest that changes in concentrations of two-component organic vapors continuously evaporating from a liquid reservoir can be estimated by the proposed model.

  17. General method for calculation of hydrogen-ion concentration in multicomponent acid-base mixtures.

    Science.gov (United States)

    Ventura, D A; Ando, H Y

    1980-08-01

    A generalized method for the rapid evaluation of complicated ionic equilibria in terms of the hydrogen-ion concentration was developed. The method was based on the derivation of a single general equation that could be used to evaluate any mixture. A tableau method also was developed which allowed calculation of the numerical solution to the general equation without computer analysis or graphical or intuitive approximations. Examples illustrating the utility of the method are presented. These examples include a mixture of barbital, citric acid, boric acid, monobasic sodium phosphate, and sodium hydroxide. Calculated hydrogen-ion concentrations showed good agreement with experimental values for simple and complex solutions. The major advantages of the method are its simplicity and the obtainment of numerical solutions without initial approximations in the calculations. However, activity corrections are not included in the calculations.

  18. Validation of analytical method to calculate the concentration of conjugated monoclonal antibody

    International Nuclear Information System (INIS)

    Alcarde, Lais F.; Massicano, Adriana V.F.; Oliveira, Ricardo S.; Araujo, Elaine B. de

    2013-01-01

    The objective of this study was to develop a quantitative analytical method using high performance liquid chromatography (HPLC) to determine the antibody concentration in conjunction with bifunctional chelator. Assays were performed using a high performance liquid chromatograph, and the following conditions were used: flow rate of 1 mL / min, 15 min run time, 0.2 M sodium phosphate buffer pH 7.0 as the mobile phase and column of molecular exclusion BioSep SEC S-3000 (300 x 7.8 mm, 5 μM - Phenomenex). The calibration curve was obtained with AcM diluted in 0.2 M sodium phosphate buffer pH 7.0 by serial dilution, yielding the concentrations: 400 μg/mL, 200 μg/mL, 100 μg/mL, 50 μg/mL, 25 μg/mL and 12.5 μg/mL. From the calibration curve calculated the equation of the line and with it the concentration of the immunoconjugate. To ensure the validity of the method accuracy and precision studies were conducted. The accuracy test consisted in the evaluation of 3 samples of known concentration, being this test performed with low concentrations (50 μg/mL), medium (100 μg/mL) and high (200 μg/mL). The precision test consisted of 3 consecutive measurements of one sample of known concentration, subject to the conditions set forth above for the other tests. The correlation coefficient of the standard curve was greater than 97%, the accuracy was satisfactory at low concentrations as well as accuracy. The method was validated by showing it for the accurate and precise determination of the concentration of the immunoconjugate. Furthermore, this assay was found to be extremely important, because using the correct mass of the protein, the radiochemical purity of the radioimmunoconjugate was above 95% in all studies

  19. Determination of scandium concentrate composition by WD-XRF and ICP-MS methods

    Science.gov (United States)

    Sarkisova, A. S.; Shibitko, A. O.; Abramov, A. V.; Rebrin, O. I.; Bunkov, G. M.; Lisienko, D. G.

    2017-09-01

    WD-XRF spectroscopy was applied for determining composition of scandium concentrate (ScC) containing 70 % scandium fluoride. Determination of ScC composition was performed using 6 glass beads reference materials produced by fusing synthesized mixture of analyte compounds with the lithium-borate flux in the ratio of 1:10. ScC powder with the known composition was then used as a powder pellet reference material to analyze scandium concentrate from technological line by external standard method. ICP-MS method was employed to control the ScC composition. The statistical data processing and metrological parameters evaluation of the analytical technique developed were carried out.

  20. Evaluation of potentially nonlethal sampling methods for monitoring mercury concentrations in smallmouth bass (Micropterus dolomieu)

    Science.gov (United States)

    Schmitt, C.J.; Brumbaugh, W.G.

    2007-01-01

    We evaluated three potentially nonlethal alternatives to fillet sampling for the determination of mercury (Hg) concentrations in smallmouth bass (Micropterus dolomieu). Fish (n = 62, 226-464 mm total length) from six sites in southern Missouri were captured by electrofishing. Blood samples (1 mL) from each fish were obtained by caudal veinipuncture with a heparinized needle and syringe. Biopsy needle (10 mm x 14 gauge; three cuts per fish; 10-20 mg total dry weight) and biopsy punch (7 mm x 5 mm in diameter, one plug per fish, 30-50 mg dry weight) samples were obtained from the area beneath the dorsal fin. Fillet samples were obtained from the opposite side of the fish. All samples were freeze-dried and analyzed for total Hg by combustion amalgamation atomic absorption spectrophotometry. Mean relative standard deviations (RSDs) of triplicate samples were similar for all four methods (2.2-2.4%), but the range of RSDs was greater for blood (0.4-5.5%) than for the muscle methods (1.8-4.0%). Total Hg concentrations in muscle were 0.0200-0.8809 ??g/g wet weight; concentrations in plug, needle, and fillet samples from each fish were nearly identical. Blood Hg concentrations were 0.0006-0.0812 ??g/mL and were highly correlated with muscle concentrations; linear regressions between log-transformed blood and fillet Hg concentrations were linear and statistically significant (p contamination. ?? 2007 Springer Science+Business Media, LLC.

  1. Development of a fluorescent method for simultaneous measurement of glucose concentrations in interstitial fluid and blood

    International Nuclear Information System (INIS)

    Shi, Ting; Li, Dachao; Li, Guoqing; Xu, Kexin; Chen, Limin; Lin, Yuan; Lu, Luo

    2013-01-01

    Continuous blood glucose monitoring is of great clinical significance to patients with diabetes. One of the effective methods to monitor blood glucose is to measure glucose concentrations of interstitial fluid (ISF). However, a time-delay problem exists between ISF and blood glucose concentrations, which results in difficulty in indicating real-time blood glucose concentrations. Therefore, we developed a fluorescent method to verify the accuracy and reliability of simultaneous ISF and blood glucose measurement, especially incorporating it into research on the delay relationship between blood and ISF glucose changes. This method is based on a competitive reaction among borate polymer, alizarin and glucose. When glucose molecules combine with borate polymers in alizarin–borate polymer competitively, changes in fluorescence intensity demonstrate changes in glucose concentrations. By applying the measured results to the blood and ISF glucose delay relationship, we were able to calculate the time delay as an average of 2.16 ± 2.05 min for ISF glucose changes with reference to blood glucose concentrations. (paper)

  2. Absorption method for determining concentrations using the Fabry-Perot interferometer

    International Nuclear Information System (INIS)

    Zhuravlev, A.A.; Izmailov, A.M.; Kuchinskii, V.V.; Sheikin, E.G.

    1986-01-01

    This study determines a means of processing experimental data using a non-ideal Fabry-Perot interferometer. Using such an instrument, one can ignore distortion induced by the instrument profile in the results of measuring the concentration of atoms. With a priori information (e.g., on the ratio of the gas temperatures for the test and illuminating discharges) the procedure of processing is substantially simplified, and one obtains simple equations for determining the concentrations of atoms in a metal. The effectiveness of this method is analyzed through an example in determining the concentration of atoms in a metal with a discharge in a hollow cathode. As a control for the experiment, the concentration is simultaneously determined by a spectral-sounding technique

  3. A Concentrated Hydrochloric Acid-based Method for Complete Recovery of DNA from Bone.

    Science.gov (United States)

    Huynen, Leon; Lambert, David M

    2015-11-01

    The successful extraction of DNA from historical or ancient animal bone is important for the analysis of discriminating genetic markers. Methods used currently rely on the digestion of bone with EDTA and proteinase K, followed by purification with phenol/chloroform and silica bed binding. We have developed a simple concentrated hydrochloric acid-based method that precludes the use of phenol/chloroform purification and can lead to a several-fold increase in DNA yield when compared to other commonly used methods. Concentrated hydrochloric acid was shown to dissolve most of the undigested bone and allowed the efficient recovery of DNA fragments <100 bases in length. This method should prove useful for the recovery of DNAs from highly degraded animal bone, such as that found in historical or ancient samples. © 2015 American Academy of Forensic Sciences.

  4. A new method research of monitoring low concentration NO and SO2 mixed gas

    Science.gov (United States)

    Bo, Peng; Gao, Chao; Guo, Yongcai; Chen, Fang

    2018-01-01

    In order to reduce the pollution of the environment, China has implemented a new ultra-low emission control regulations for polluting gas, requiring new coal-fired power plant emissions SO2 less than 30ppm, NO less than 75ppm, NO2 less than 50ppm, Monitoring low concentration of NO and SO2 mixed gases , DOAS technology facing new challenges, SO2 absorb significantly weaken at the original absorption peak, what more the SNR is very low, it is difficult to extract the characteristic signal, and thus cannot obtain its concentration. So it cannot separate the signal of NO from the mixed gas at the wavelength of 200 230nm through the law of spectral superposition, it cannot calculate the concentration of NO. The classical DOAS technology cannot meet the needs of monitoring. In this paper, we found another absorption spectrum segment of SO2, the SNR is 10 times higher than before, Will not be affected by NO, can calculate the concentration of SO2 accurately, A new method of segmentation and demagnetization separation technology of spectral signals is proposed, which achieves the monitoring the low concentration mixed gas accurately. This function cannot be achieved by the classical DOAS. Detection limit of this method is 0.1ppm per meter which is higher than before, The relative error below 5% when the concentration between 0 5ppm, the concentration of NO between 6 75ppm and SO2 between 6 30ppm the relative error below 1.5%, it has made a great breakthrough In the low concentration of NO and SO2 monitoring. It has great scientific significance and reference value for the development of coal-fired power plant emission control, atmospheric environmental monitoring and high-precision on-line instrumentation.

  5. Method of controlling flow rate and concentration of centrifugal gas separation cascade

    International Nuclear Information System (INIS)

    Hayakawa, Katsuyuki; Ishiguro, Shin-ichi; Shirahashi, Junji; Omae, Masayoshi.

    1976-01-01

    Object: To permit efficient adjustment of product concentration by systematically combining a stage cut detection method and stage cut correction method. Structure: One or more stages in a centrifugal gas separation cascade are made to be correction stages, in which the stage cut of the cascade is corrected to thereby control the flow rate. In the correction stage or stages, a supply side header is provided with a pressure detector, and concentration side and loss side headers are provided with respective flow control valves. The concentration side and loss side headers are connected together by bypass ducts, which are provided with respective on-off valves, and the flow control valves and on-off valves are connected to a computor. A design pressure pattern which is memorized in the computor and an input pressure pattern are compared by the computor, whereby the correction of the stage cut is obtained in order to control the stage flow rate. (Nakamura, S.)

  6. The method to calculate concentration of CO2 and H2S in the liquid phase.

    Directory of Open Access Journals (Sweden)

    YUDIN Pavel Evgenievich

    2017-08-01

    Full Text Available The article proposes the method to calculate the necessary concentration of dissolved gases in the liquid phase. It also deals with development of the computer program that could consider all the main parameters of the tests. The numerous mathematical calculations resulted in formulation of the method to calculate concentration of dissolved gases in the liquid phase. The implementation of the developed model in the form of the software product «Autoclave 2.1» is presented. The developed methodology for calculating the concentration of dissolved gases in the liquid phase is designed to perform accelerated tests that concern resistance of internal anticorrosive coatings of pipelines to aggressive media and explosive decompression, to intensify corrosion processes and to identify the main mechanisms and patterns of changes in the physical, mechanical and operational properties of coatings from hydrothermal influences of fishing environments.

  7. Method for recovering aroma concentrate from a caffeine- or theobromine-comprising food base material

    NARCIS (Netherlands)

    Kattenberg, H.R.; Willemsen, J.H.A.; Starmans, D.A.J.; Hoving, H.D.; Winters, M.G.M.

    2002-01-01

    Described is a method for recovering aroma concentrate from a caffeine- or theobromine-comprising food base material, such as coffee or tea, and in particular cocoa, at least comprising the steps of: introducing the food base material into an aqueous extractant and incubating the food base material

  8. Method for determining the absolute number concentration of nanoparticles from electrospray sources.

    Science.gov (United States)

    Li, Mingdong; Guha, Suvajyoti; Zangmeister, Rebecca; Tarlov, Michael J; Zachariah, Michael R

    2011-12-20

    We have developed a simple, fast, and accurate method to measure the absolute number concentration of nanoparticles in solution. The method combines electrospray differential mobility analysis (ES-DMA) with a statistical analysis of droplet-induced oligomer formation. A key feature of the method is that it allows determination of the absolute number concentration of particles by knowing only the droplet size generated from a particular ES source, thereby eliminating the need for sample-specific calibration standards or detailed analysis of transport losses. The approach was validated by comparing the total number concentration of monodispersed Au nanoparticles determined by ES-DMA with UV/vis measurements. We also show that this approach is valid for protein molecules by quantifying the absolute number concentration of Rituxan monoclonal antibody in solution. The methodology is applicable for quantification of any electrospray process coupled to an analytical tool that can distinguish monomers from higher order oligomers. The only requirement is that the droplet size distribution be evaluated. For users only interested in implementation of the theory, we provide a section that summarizes the relevant formulas. This method eliminates the need for sample-specific calibration standards or detailed analysis of transport losses. © 2011 American Chemical Society

  9. A revised method to calculate the concentration time integral of atmospheric pollutants

    International Nuclear Information System (INIS)

    Voelz, E.; Schultz, H.

    1980-01-01

    It is possible to calculate the spreading of a plume in the atmosphere under nonstationary and nonhomogeneous conditions by introducing the ''particle-in-cell'' method (PIC). This is a numerical method by which the transport of and the diffusion in the plume is reproduced in such a way, that particles representing the concentration are moved time step-wise in restricted regions (cells) and separately with the advection velocity and the diffusion velocity. This has a systematical advantage over the steady state Gaussian plume model usually used. The fixed-point concentration time integral is calculated directly instead of being substituted by the locally integrated concentration at a constant time as is done in the Gaussian model. In this way inaccuracies due to the above mentioned computational techniques may be avoided for short-time emissions, as may be seen by the fact that both integrals do not lead to the same results. Also the PIC method enables one to consider the height-dependent wind speed and its variations while the Gaussian model can be used only with averaged wind data. The concentration time integral calculated by the PIC method results in higher maximum values in shorter distances to the source. This is an effect often observed in measurements. (author)

  10. Comparison of point-of-care methods for preparation of platelet concentrate (platelet-rich plasma).

    Science.gov (United States)

    Weibrich, Gernot; Kleis, Wilfried K G; Streckbein, Philipp; Moergel, Maximilian; Hitzler, Walter E; Hafner, Gerd

    2012-01-01

    This study analyzed the concentrations of platelets and growth factors in platelet-rich plasma (PRP), which are likely to depend on the method used for its production. The cellular composition and growth factor content of platelet concentrates (platelet-rich plasma) produced by six different procedures were quantitatively analyzed and compared. Platelet and leukocyte counts were determined on an automatic cell counter, and analysis of growth factors was performed using enzyme-linked immunosorbent assay. The principal differences between the analyzed PRP production methods (blood bank method of intermittent flow centrifuge system/platelet apheresis and by the five point-of-care methods) and the resulting platelet concentrates were evaluated with regard to resulting platelet, leukocyte, and growth factor levels. The platelet counts in both whole blood and PRP were generally higher in women than in men; no differences were observed with regard to age. Statistical analysis of platelet-derived growth factor AB (PDGF-AB) and transforming growth factor β1 (TGF-β1) showed no differences with regard to age or gender. Platelet counts and TGF-β1 concentration correlated closely, as did platelet counts and PDGF-AB levels. There were only rare correlations between leukocyte counts and PDGF-AB levels, but comparison of leukocyte counts and PDGF-AB levels demonstrated certain parallel tendencies. TGF-β1 levels derive in substantial part from platelets and emphasize the role of leukocytes, in addition to that of platelets, as a source of growth factors in PRP. All methods of producing PRP showed high variability in platelet counts and growth factor levels. The highest growth factor levels were found in the PRP prepared using the Platelet Concentrate Collection System manufactured by Biomet 3i.

  11. A Quantification Method for Breast Tissue Thickness and Iodine Concentration Using Photon-Counting Detector.

    Science.gov (United States)

    Han, Seokmin

    2015-10-01

    The purpose of contrast-enhanced digital mammography (CEDM) is to facilitate detection and characterization of the lesions in the breast using intravenous injection of an iodinated contrast agent. CEDM produces iodine images with gray levels proportional to iodine concentration at each pixel, which can be considered as quantification of iodine. While dual-energy CEDM requires an accurate knowledge of the thickness of compressed breast for the quantification, it is known that the accuracy of the built-in thickness measurement is not satisfactory. Triple-energy CEDM, which can provide a third image, can alleviate the limitation of dual-energy CEDM. If triple exposure technique is applied, it can lead to increased risk of motion artifact. An energy-resolving photon-counting detector (PCD) that can acquire multispectral X-ray images can reduce the risk of motion artifact. In this research, an easily implementable method for iodine quantification in breast imaging was suggested, and it was applied to the images of breast phantom with various iodine concentrations. The iodine concentrations in breast phantom simulate lesions filled with different iodine concentrations in the breast. The result shows that the proposed method can quantify the iodine concentrations in breast phantom accurately.

  12. Using depolarization to quantify ice nucleating particle concentrations: a new method

    Directory of Open Access Journals (Sweden)

    J. Zenker

    2017-12-01

    Full Text Available We have developed a new method to determine ice nucleating particle (INP concentrations observed by the Texas A&M University continuous flow diffusion chamber (CFDC under a wide range of operating conditions. In this study, we evaluate differences in particle optical properties detected by the Cloud and Aerosol Spectrometer with POLarization (CASPOL to differentiate between ice crystals, droplets, and aerosols. The depolarization signal from the CASPOL instrument is used to determine the occurrence of water droplet breakthrough (WDBT conditions in the CFDC. The standard procedure for determining INP concentration is to count all particles that have grown beyond a nominal size cutoff as ice crystals. During WDBT this procedure overestimates INP concentration, because large droplets are miscounted as ice crystals. Here we design a new analysis method based on depolarization ratio that can extend the range of operating conditions of the CFDC. The method agrees reasonably well with the traditional method under non-WDBT conditions with a mean percent error of ±32.1 %. Additionally, a comparison with the Colorado State University CFDC shows that the new analysis method can be used reliably during WDBT conditions.

  13. A novel method for assessing chronic cortisol concentrations in dogs using the nail as a source.

    Science.gov (United States)

    Mack, Z; Fokidis, H B

    2017-04-01

    Cortisol, a glucocorticoid secreted in response to stress, is used to assess adrenal function and mental health in clinical settings. Current methods assess cortisol sources that reflect short-term secretion that can vary with current stress state. Here, we present a novel method for the extraction and quantification of cortisol from the dog nail using solid phase extraction coupled to enzyme-linked immunosorbent assay. Validation experiments demonstrated accuracy (r = 0.836, P cortisol concentrations were positively correlated to an established hair cortisol method (r = 0.736, P cortisol concentrations did not differ with dog sex, breed, age, or weights; however, sample size limitations may preclude statistical significance. Nail cortisol may provide information on cortisol secretion integrated over the time corresponding to nail growth and may be useful as a tool for diagnosing stress and adrenal disorders in dogs. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Estimation of very low concentrations of Ruthenium by spectrophotometric method using barbituric acid as complexing agent

    International Nuclear Information System (INIS)

    Ramakrishna Reddy, S.; Srinivasan, R.; Mallika, C.; Kamachi Mudali, U.; Natarajan, R.

    2012-01-01

    Spectrophotometric method employing numerous chromogenic reagents like thiourea, 1,10-phenanthroline, thiocyanate and tropolone is reported in the literature for the estimation of very low concentrations of Ru. A sensitive spectrophotometric method has been developed for the determination of ruthenium in the concentration range 1.5 to 6.5 ppm in the present work. This method is based on the reaction of ruthenium with barbituric acid to produce ruthenium(ll)tris-violurate, (Ru(H 2 Va) 3 ) -1 complex which gives a stable deep-red coloured solution. The maximum absorption of the complex is at 491 nm due to the inverted t 2g → Π(L-L ligand) electron - transfer transition. The molar absorptivity of the coloured species is 9,851 dm 3 mol -1 cm -1

  15. Verification of statistical method CORN for modeling of microfuel in the case of high grain concentration

    Energy Technology Data Exchange (ETDEWEB)

    Chukbar, B. K., E-mail: bchukbar@mail.ru [National Research Center Kurchatov Institute (Russian Federation)

    2015-12-15

    Two methods of modeling a double-heterogeneity fuel are studied: the deterministic positioning and the statistical method CORN of the MCU software package. The effect of distribution of microfuel in a pebble bed on the calculation results is studied. The results of verification of the statistical method CORN for the cases of the microfuel concentration up to 170 cm{sup –3} in a pebble bed are presented. The admissibility of homogenization of the microfuel coating with the graphite matrix is studied. The dependence of the reactivity on the relative location of fuel and graphite spheres in a pebble bed is found.

  16. Verification of statistical method CORN for modeling of microfuel in the case of high grain concentration

    Science.gov (United States)

    Chukbar, B. K.

    2015-12-01

    Two methods of modeling a double-heterogeneity fuel are studied: the deterministic positioning and the statistical method CORN of the MCU software package. The effect of distribution of microfuel in a pebble bed on the calculation results is studied. The results of verification of the statistical method CORN for the cases of the microfuel concentration up to 170 cm-3 in a pebble bed are presented. The admissibility of homogenization of the microfuel coating with the graphite matrix is studied. The dependence of the reactivity on the relative location of fuel and graphite spheres in a pebble bed is found.

  17. A simple and inexpensive method to control oxygen concentrations within physiological and neoplastic ranges.

    Science.gov (United States)

    Penketh, P G; Shyam, K; Baumann, R P; Ratner, E S; Sartorelli, A C

    2015-12-15

    Traditional methods for regulating oxygen concentration ([O2]) in in vitro experiments over the range found in normal and tumor tissues require the use of expensive equipment to generate controlled gas atmospheres or the purchase of a range of gas cylinders with certified O2 percentages. Here we describe a simple and inexpensive enzymatic method for generating low, precise steady-state [O2] levels that are stable for several hours. This method is particularly applicable to the in vitro study of some classes of hypoxia-targeted antitumor prodrugs and bioreductively activated agents. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Quantification of total aluminium concentrations in food samples at trace levels by INAA and PIGE methods

    International Nuclear Information System (INIS)

    Nanda, Braja B.; Acharya, R.

    2017-01-01

    Total aluminium contents in various food samples were determined by Instrumental Neutron Activation Analysis (INAA) and Particle Induced Gamma-ray Emission (PIGE) methods. A total of 16 rice samples, collected from the field, were analyzed by INAA using reactor neutrons from Dhruva reactor. Whereas a total 17 spices collected from market, were analyzed by both INAA and PIGE methods in conjunction with high resolution gamma-ray spectrometry. Aluminium concentration values were found to be in the range of 19-845 mg kg -1 for spices and 15-104 mg kg -1 for rice samples. The methods were validated by analyzing standard reference materials (SRMs) form NIST. (author)

  19. The role and importance of ozone for atmospheric chemistry and methods for measuring its concentration

    Directory of Open Access Journals (Sweden)

    Marković Dragan M.

    2003-01-01

    Full Text Available Depending on where ozone resides, it can protect or harm life on Earth. The thin layer of ozone that surrounds Earth acts as a shield protecting the planet from irradiation by UV light. When it is close to the planet's surface, ozone is a powerful photochemical oxidant that damage, icons frescos, museum exhibits, rubber, plastic and all plant and animal life. Besides the basic properties of some methods for determining the ozone concentration in working and living conditions, this paper presents a detailed description of the electrochemical method. The basic properties of the electrochemical method are used in the construction of mobile equipment for determining the sum of oxidants in the atmosphere. The equipment was used for testing the determination of the ozone concentration in working rooms, where the concentration was at a high level and caused by UV radiation or electrostatic discharge. According to the obtained results, it can be concluded that this equipment for determining the ozone concentration in the atmosphere is very powerful and reproducible in measurements.

  20. Standard method for the determination of activity concentration of 90Sr in water

    International Nuclear Information System (INIS)

    1987-01-01

    The subject of the standard is the determination of the radioactive concentration of 90 Sr in surface waters, in ground water and in drinking water, by measuring the radioactivity of the daughter isotope 90 Y that was previously separated by a selective radiochemical method. Yttrium ions are extracted from alkaline earth metal cations by tributil-phosphate equilibrated with concentrated nitric acid. The ions are then reextracted into distilled water and precipitated in the form of yttrium-oxalate. Radioactivity of the precipitate is determined based on the measurement of the β-disintegration rate using a low-background nuclear instrument. (V.N.)

  1. Standard test method for uranium and plutonium concentrations and isotopic abundances by thermal ionization mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the determination of the concentration and isotopic composition of uranium and plutonium in solutions. The purified uranium or plutonium from samples ranging from nuclear materials to environmental or bioassay matrices is loaded onto a mass spectrometric filament. The isotopic ratio is determined by thermal ionization mass spectrometry, the concentration is determined by isotope dilution. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish safety and health practices and determine the applicability of regulatory limitations prior to use.

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

    Science.gov (United States)

    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.

  3. Standard Test Method for Determining Thermal Performance of Tracking Concentrating Solar Collectors

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1987-01-01

    1.1 This test method covers the determination of thermal performance of tracking concentrating solar collectors that heat fluids for use in thermal systems. 1.2 This test method applies to one- or two-axis tracking reflecting concentrating collectors in which the fluid enters the collector through a single inlet and leaves the collector through a single outlet, and to those collectors where a single inlet and outlet can be effectively provided, such as into parallel inlets and outlets of multiple collector modules. 1.3 This test method is intended for those collectors whose design is such that the effects of diffuse irradiance on performance is negligible and whose performance can be characterized in terms of direct irradiance. Note 1—For purposes of clarification, this method shall apply to collectors with a geometric concentration ratio of seven or greater. 1.4 The collector may be tested either as a thermal collection subsystem where the effects of tracking errors have been essentially removed from t...

  4. An optical-density-based feedback feeding method for ammonium concentration control in Spirulina platensis cultivation.

    Science.gov (United States)

    Bao, Yilu; Wen, Shumei; Cong, Wei; Wu, Xia; Ning, Zhengxiang

    2012-07-01

    Cultivation of Spirulina platensis using ammonium salts or wastewater containing ammonium as alternative nitrogen sources is considered as a commercial way to reduce the production cost. In this research, by analyzing the relationship between biomass production and ammonium- N consumption in the fed-batch culture of Spirulina platensis using ammonium bicarbonate as a nitrogen nutrient source, an online adaptive control strategy based on optical density (OD) measurements for controlling ammonium feeding was presented. The ammonium concentration was successfully controlled between the cell growth inhibitory and limiting concentrations using this OD-based feedback feeding method. As a result, the maximum biomass concentration (2.98 g/l), productivity (0.237 g/l·d), nitrogen-to-cell conversion factor (7.32 gX/gN), and contents of protein (64.1%) and chlorophyll (13.4 mg/g) obtained by using the OD-based feedback feeding method were higher than those using the constant and variable feeding methods. The OD-based feedback feeding method could be recognized as an applicable way to control ammonium feeding and a benefit for Spirulina platensis cultivations.

  5. Controlling method for impurity concentration in the feedwater system of a BWR type reactor

    International Nuclear Information System (INIS)

    Yamazaki, Kenji

    1987-01-01

    Purpose: To decrease ionic radioactive deposition and reduce the exposure dose upon inspection in the recycling system of a nuclear reactor. Method: Fe concentration is analyzed based on the crud concentration measured by a turbidimeter and the concentration is calculated. Further, Ni density is analyzed by an ion crossed meter and the density is calculated. From the calculated values, the density between Fe density and Ni density, i.e., Fe/Ni is calculated. If the calculated value for Fe/Ni is lower than a setting value (Fe/Ni = 2), an open signal is outputted for an iron injection valve disposed at the midway of a pipeway connected from a tank containing suspended iron oxide or iron hydroxide to a feedwater pipe. Then, the opening degree of the iron injection valve is adjusted based on the deviation value between the setting value (Fe/Ni = 2) and the calculated value for Fe/Ni. (Yoshino, Y.)

  6. Method for concentration and separation of biological organisms by ultrafiltration and dielectrophoresis

    Science.gov (United States)

    Simmons, Blake A.; Hill, Vincent R.; Fintschenko, Yolanda; Cummings, Eric B.

    2012-09-04

    Disclosed is a method for monitoring sources of public water supply for a variety of pathogens by using a combination of ultrafiltration techniques together dielectrophoretic separation techniques. Because water-borne pathogens, whether present due to "natural" contamination or intentional introduction, would likely be present in drinking water at low concentrations when samples are collected for monitoring or outbreak investigations, an approach is needed to quickly and efficiently concentrate and separate particles such as viruses, bacteria, and parasites in large volumes of water (e.g., 100 L or more) while simultaneously reducing the sample volume to levels sufficient for detecting low concentrations of microbes (e.g., <10 mL). The technique is also designed to screen the separated microbes based on specific conductivity and size.

  7. Predicting contaminant concentration at a pumping well with method combining statistical and mathematical models

    Science.gov (United States)

    Lim, J.; Bae, G.; Kaown, D.; Lee, K.

    2008-12-01

    In predicting contamination of groundwater, both the statistical and mathematical modeling methods are used in combination with one another with the aim of taking the advantage of each method. With a mathematical model based on the backward transport equation, probabilistic capture zones of pumping wells are delineated. And these capture zones are used as a buffer zone of each pumping well for a statistical regression model. Tobit regression model is used to investigate the influence of land use on contaminant concentration at a pumping well. Using probabilistic capture zones as buffer zones instead of circular zones, flow and transport regime near pumping wells can be considered in the regression model as well as different types of land use. The method is applied to a small agricultural basin in Chuncheon, Korea which is occupied by vegetation fields, orchards and small barns. Accordingly, chemical fertilizers and manures are frequently applied on the land surface for agricultural purposes. Area of land use type - vegetation fields, orchards, and small barns - within the probabilistic capture zones, land slope, and elevation are used as explanatory variables. As dependent variable, nitrate concentrations observed at pumping wells are used. The proposed method gives better prediction of nitrate concentration than the general regression model using circular buffer zones does. Also, it is expected that the proposed method can be effectively used to relate the loading mass of fertilizer and its concentration in ground water at pumping wells and further to suggest an allowable loading mass of fertilizer for preservation of ground water quality under regulatory limits.

  8. Uncertainty assessment of the breath methane concentration method to determine methane production of dairy cows.

    Science.gov (United States)

    Wu, Liansun; Koerkamp, Peter W G Groot; Ogink, Nico

    2018-02-01

    The breath methane concentration method uses the methane concentrations in the cow's breath during feed bin visits as a proxy for the methane production rate. The objective of this study was to assess the uncertainty of a breath methane concentration method in a feeder and its capability to measure and rank cows' methane production. A range of controlled methane fluxes from a so-called artificial reference cow were dosed in a feed bin, and its exhaled air was sampled by a tube inside the feeder and analyzed. The artificial reference cow simulates the lungs, respiratory tract, and rumen of a cow and releases a variable methane flux to generate a concentration pattern in the exhaled breath that closely resembles a real cow's pattern. The strength of the relation between the controlled methane release rates of the artificial reference cow and the measured methane concentrations was analyzed by linear regression, using the coefficient of determination (R 2 ) and the residual standard error as performance indicators. The effect of error sources (source-sampling distance, air turbulence, and cow's head movement) on this relation was experimentally investigated, both under laboratory and barn conditions. From the laboratory to the dairy barn at the 30-cm sampling distance, the R 2 -value decreased from 0.97 to 0.37 and the residual standard error increased from 75 to 86 ppm as a result of barn air turbulence, the latter increasing to a theoretical 94 ppm if modeled variability due to cow's head movement was accounted for as well. In practice, the effect of these random errors can be compensated by sampling strategies including repeated measurements on each cow over time, thus increasing the distinctive power between cows. However, systematic errors that may disturb the relation between concentration and production rate, such as cow variation in air exhalation rate and air flow patterns around sampling locations that differ between barns, cannot be compensated by repeated

  9. CFD Method for Predicting Annular Pressure Losses and Cuttings Concentration in Eccentric Horizontal Wells

    Directory of Open Access Journals (Sweden)

    Titus N. Ofei

    2014-01-01

    Full Text Available In oil and gas drilling operations, predictions of pressure losses and cuttings concentration in the annulus are very complex due to the combination of interacting drilling parameters. Past studies have proposed many empirical correlations to estimate pressure losses and cuttings concentration. However, these developed correlations are limited to their experimental data range and setup, and hence, they cannot be applicable to all cases. CFD methods have the advantages of handling complex multiphase flow problems, as well as, an unlimited number of physical and operational conditions. The present study employs the inhomogeneous (Eulerian-Eulerian model to simulate a two-phase solid-fluid flow and predict pressure losses and cuttings concentration in eccentric horizontal annuli as a function of varying drilling parameters: fluid velocity, diameter ratio (ratio of inner pipe diameter to outer pipe diameter, inner pipe rotation speed, and fluid type. Experimental data for pressure losses and cuttings concentration from previous literature compared very well with simulation data, confirming the validity of the current model. The study shows how reliable CFD methods can replicate the actual, yet complex oil and gas drilling operations.

  10. Phosphorus Concentrations in Sequentially Fractionated Soil Samples as Affected by Digestion Methods

    Science.gov (United States)

    do Nascimento, Carlos A. C.; Pagliari, Paulo H.; Schmitt, Djalma; He, Zhongqi; Waldrip, Heidi

    2015-01-01

    Sequential fractionation has helped improving our understanding of the lability and bioavailability of P in soil. Nevertheless, there have been no reports on how manipulation of the different fractions prior to analyses affects the total P (TP) concentrations measured. This study investigated the effects of sample digestion, filtration, and acidification on the TP concentrations determined by ICP-OES in 20 soil samples. Total P in extracts were either determined without digestion by ICP-OES, or ICP-OES following block digestion, or autoclave digestion. The effects of sample filtration, and acidification on undigested alkaline extracts prior to ICP-OES were also evaluated. Results showed that, TP concentrations were greatest in the block-digested extracts, though the variability introduced by the block-digestion was the highest. Acidification of NaHCO3 extracts resulted in lower TP concentrations, while acidification of NaOH randomly increased or decreased TP concentrations. The precision observed with ICP-OES of undigested extracts suggests this should be the preferred method for TP determination in sequentially extracted samples. Thus, observations reported in this work would be helpful in appropriate sample handling for P determination, thereby improving the precision of P determination. The results are also useful for literature data comparison and discussion when there are differences in sample treatments. PMID:26647644

  11. Method for calculating ionic and electronic defect concentrations in y-stabilised zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Poulsen, F.W. [Risoe National Lab., Materials Research Dept., Roskilde (Denmark)

    1997-10-01

    A numerical (trial and error) method for calculation of concentration of ions, vacancies and ionic and electronic defects in solids (Brouwer-type diagrams) is presented. No approximations or truncations of the set of equations describing the chemistry for the various defect regions are used. Doped zirconia and doped thoria with simultaneous presence of protonic and electronic defects are taken as examples: 7 concentrations as function of oxygen partial pressure and/or water vapour partial pressure are determined. Realistic values for the equilibrium constants for equilibration with oxygen gas and water vapour, as well as for the internal equilibrium between holes and electrons were taken from the literature. The present mathematical method is versatile - it has also been employed by the author to treat more complex systems, such as perovskite structure oxides with over- and under-stoichiometry in oxygen, cation vacancies and simultaneous presence of protons. (au) 6 refs.

  12. Two methods for calculating regional cerebral blood flow from emission computed tomography of inert gas concentrations

    DEFF Research Database (Denmark)

    Kanno, I; Lassen, N A

    1979-01-01

    Two methods are described for calculation of regional cerebral blood flow from completed tomographic data of radioactive inert gas distribution in a slice of brain tissue. It is assumed that the tomographic picture gives the average inert gas concentration in each pixel over data collection perio...... are implemented using synthetic data of xenon-133 emission computed tomography and some of the difficulties likely to be encountered in practice are stressed.......Two methods are described for calculation of regional cerebral blood flow from completed tomographic data of radioactive inert gas distribution in a slice of brain tissue. It is assumed that the tomographic picture gives the average inert gas concentration in each pixel over data collection periods...

  13. Trace and low concentration co2 removal methods and apparatus utilizing metal organic frameworks

    KAUST Repository

    Eddaoudi, Mohamed

    2016-03-10

    In general, this disclosure describes techniques for removing trace and low concentration CO2 from fluids using SIFSIX-n-M MOFs, wherein n is at least two and M is a metal. In some embodiments, the metal is zinc or copper. Embodiments include devices comprising SIFSIX-n-M MOFs for removing CO2 from fluids. In particular, embodiments relate to devices and methods utilizing SIFSIX-n-M MOFs for removing CO2 from fluids, wherein CO2 concentration is trace. Methods utilizing SIFSIX-n-M MOFs for removing CO2 from fluids can occur in confined spaces. SIFSIX-n-M MOFs can comprise bidentate organic ligands. In a specific embodiment, SIFSIX-n-M MOFs comprise pyrazine or dipryidilacetylene ligands.

  14. 40 CFR Table 4 of Subpart Bbbbbbb... - Continuous Compliance Demonstration Methods With the Emission Reduction and PM Concentration...

    Science.gov (United States)

    2010-07-01

    ... Methods With the Emission Reduction and PM Concentration Requirements 4 Table 4 of Subpart BBBBBBB of Part... Concentration Requirements If you are demonstrating compliance with the * * * You must demonstrate continuous...) or an outlet concentration of 0.03 gr/dscf or less Using one of the following monitoring methods:a. A...

  15. A New Method for the Determination of Sucrose Concentration in a Pure and Impure System: Spectrophotometric Method

    Directory of Open Access Journals (Sweden)

    A. Borji

    2017-01-01

    Full Text Available Analytical chemistry is a set of procedures and techniques used to identify and quantify the composition of a sample of material. It is also focused on improvements in experimental design and the creation of new measurement tools. Analytical chemistry has broad applications to forensics, medicine, science, and engineering. The objective of this study is to develop a new method of sucrose dosage using a spectrophotometry method in a pure and impure system (presence of glucose and fructose. The work performed shows the reliability of this method. A model linking sucrose solution absorbance and mass percentage of glucose and fructose has been developed using experimental design. The results obtained show that all the investigated factors (sucrose concentration, mass percentage of glucose, and mass percentage of fructose have a positive effect on the absorbance. The effect of the interaction between glucose and fructose on the absorbance is very significant.

  16. Simplified "No-D" NMR Methods for Routine Analysis and Organometallic Reagent Concentration Determination.

    Science.gov (United States)

    Fallon, Thomas; Meek, Tamaryn

    2017-11-03

    The use of tetrachloroethylene spiked with tetramethylsilane as a solvent for routine NMR analysis has been evaluated. Excellent quality spectra are reliably obtained, comparable to samples run in chloroform-d. Validation of this method is presented, together with the spectral data of commonly encountered trace impurities. In addition, NMR analysis for the concentration determination of organometallic reagents has been simplified using double-walled NMR tubes using a calibrated external reference solution within a hermetically sealed chamber.

  17. Comparing concentration methods: parasitrap® versus Kato-Katz for ...

    African Journals Online (AJOL)

    Cite as: Mirante C, Clemente I, Zambu G, Alexandre C, Ganga T, Mayer C, Brito M. Comparing concentration methods: parasiTrap® ver- sus Kato-Katz for studying the prevalence of helminths in Bengo Province, Angola. Afri Health Sci 2016;16(3): 698-703. DOI: http://dx.doi. org/10.4314/ahs.v16i3.9. Corresponding author:.

  18. Method for recovering aroma concentrate from a caffeine- or theobromine-comprising food base material

    OpenAIRE

    Kattenberg, H.R.; Willemsen, J.H.A.; Starmans, D.A.J.; Hoving, H.D.; Winters, M.G.M.

    2002-01-01

    Described is a method for recovering aroma concentrate from a caffeine- or theobromine-comprising food base material, such as coffee or tea, and in particular cocoa, at least comprising the steps of: introducing the food base material into an aqueous extractant and incubating the food base material at a suitable temperature and for a suitable period, substantial extraction of the aromas taking place to form an aqueous food extract, pervaporating the food extract using a hydrophobic pervaporat...

  19. Determination of chicken and turkey plasma and serum protein concentrations by refractometry and the biuret method.

    Science.gov (United States)

    Andreasen, C B; Latimer, K S; Kircher, I M; Brown, J

    1989-01-01

    Plasma and serum protein concentrations were determined in chickens and turkeys by refractometry (with human and veterinary refractometers) and by the biuret method. Chicken and turkey serum protein values were significantly lower than respective plasma protein values according to both methods. Refractometer readings for both plasma and serum correlated closely with the results of the biuret test (r2 = 0.72 to 0.97). These findings indicate that plasma and serum protein values may be determined accurately in chickens and turkeys with a handheld refractometer.

  20. Novel method for online monitoring of dissolved N2O concentrations through a gas stripping device.

    Science.gov (United States)

    Mampaey, Kris E; van Dongen, Udo G J M; van Loosdrecht, Mark C M; Volcke, Eveline I P

    2015-01-01

    Nitrous oxide emissions from wastewater treatment plants are currently measured by online gas phase analysis or grab sampling from the liquid phase. In this study, a novel method is presented to monitor the liquid phase N2O concentration for aerated as well as non-aerated conditions/reactors, following variations both in time and in space. The monitoring method consists of a gas stripping device, of which the measurement principle is based on a continuous flow of reactor liquid through a stripping flask and subsequent analysis of the N2O concentration in the stripped gas phase. The method was theoretically and experimentally evaluated for its fit for use in the wastewater treatment context. Besides, the influence of design and operating variables on the performance of the gas stripping device was addressed. This method can easily be integrated with online off-gas measurements and allows to better investigate the origin of the gas emissions from the treatment plant. Liquid phase measurements of N2O are of use in mitigation of these emissions. The method can also be applied to measure other dissolved gasses, such as methane, being another important greenhouse gas.

  1. A standardized method to determine the concentration of extracellular vesicles using tunable resistive pulse sensing

    Directory of Open Access Journals (Sweden)

    Robert Vogel

    2016-09-01

    Full Text Available Background: Understanding the pathogenic role of extracellular vesicles (EVs in disease and their potential diagnostic and therapeutic utility is extremely reliant on in-depth quantification, measurement and identification of EV sub-populations. Quantification of EVs has presented several challenges, predominantly due to the small size of vesicles such as exosomes and the availability of various technologies to measure nanosized particles, each technology having its own limitations. Materials and Methods: A standardized methodology to measure the concentration of extracellular vesicles (EVs has been developed and tested. The method is based on measuring the EV concentration as a function of a defined size range. Blood plasma EVs are isolated and purified using size exclusion columns (qEV and consecutively measured with tunable resistive pulse sensing (TRPS. Six independent research groups measured liposome and EV samples with the aim to evaluate the developed methodology. Each group measured identical samples using up to 5 nanopores with 3 repeat measurements per pore. Descriptive statistics and unsupervised multivariate data analysis with principal component analysis (PCA were used to evaluate reproducibility across the groups and to explore and visualise possible patterns and outliers in EV and liposome data sets. Results: PCA revealed good reproducibility within and between laboratories, with few minor outlying samples. Measured mean liposome (not filtered with qEV and EV (filtered with qEV concentrations had coefficients of variance of 23.9% and 52.5%, respectively. The increased variance of the EV concentration measurements could be attributed to the use of qEVs and the polydisperse nature of EVs. Conclusion: The results of this study demonstrate the feasibility of this standardized methodology to facilitate comparable and reproducible EV concentration measurements.

  2. Processing method and corn cultivar affected anthocyanin concentration from dried distillers grains with solubles.

    Science.gov (United States)

    Dia, Vermont P; Wang, Zhaoqin; West, Megan; Singh, Vijay; West, Leslie; de Mejia, Elvira Gonzalez

    2015-04-01

    Anthocyanins are water-soluble pigments with health benefits and potential use as food colorants. The objectives of this work were to (1) determine optimum parameters for the extraction of anthocyanins from dried distillers grain with solubles (DDGS), (2) develop a method of anthocyanin extraction from DDGS, (3) quantify and identify the extracted anthocyanins, and (4) determine the effect of processing methods and corn cultivars on anthocyanin concentration. DDGS samples were prepared from purple (PC) and dark (DC) corn and processed using conventional enzymes (C) and granular starch hydrolyzing enzymes (GC). Three independent variables (ethanol concentration (0, 12.5, and 25%); liquid-to-solid ratio (30:1, 40:1, 50:1 mL/g); and extraction temperature (4, 22, and 40 °C)) and two dependent variables (anthocyanin concentration and a-value (redness)) were used. Results showed that dark corn DDGS gave anthocyanin concentration higher than that of purple corn. The GC process showed total anthocyanin concentration higher than that of the conventional method of DDGS production. The maximum anthocyanin concentration was obtained at 12.5% ethanol, 40:1 liquid-to-solid ratio, and 22 °C for C-PC [321.0 ± 37.3 μg cyanidin-3 glucoside (C3G) equivalent/g DDGS]. For GC-PC, 25% ethanol, 30:1 liquid-to-solid ratio, and 22 °C gave 741.4 ± 12.8 μg C3G equivalent/g DDGS. For GC-DC, 12.5% ethanol, 40:1 liquid-to-solid ratio, and 40 °C extraction gave 1573.4 ± 84.0 μg C3G equivalent/g DDGS. LC/MS-MS analysis showed that the major anthocyanins were cyanidin-3-glucoside, cyanidin-3-(6″-malonyl) glucoside, and peonidin-3-(6″malonyl) glucoside. In conclusion, anthocyanin extraction from colored corn DDGS can be optimized using 12.5% ethanol, 40:1 mL/g ratio, and 22 °C.

  3. Pre-concentration of Pb, Cd, and Ni in river water using back extraction method

    Science.gov (United States)

    Koesmawati, T. A.; Moelyo, M.; Rizqiani, A.; Tanuwidjaja, S.

    2017-03-01

    Dissolved heavy metals such as Pb, Cd and Ni in natural water can be the source of harmful contaminant for human health and aquatic life in aquatic systems. Particular treatment is needed for low concentration of metals in water samples using Flame Atomic Absorption Spectrophotometer (FAAS) measurement. The sample was collected from Cikapundung River in Siliwangi and Dayeuhkolot, Bandung. Back-extraction procedure was used as an alternative method for pre-concentration in trace metal analysis. Ammonium Pyrrolidine Dithiocarbamate (APDC) and Diethylammonium Diethyldithiocarbamate (DDDC) in Methyl Isobuthyl Ketone (MIBK) were used as chelating agent. In this study, the application of back-extraction procedure using APDC/DDDC chelating agent in MIBK resulted the detection limit of 2.2 μg/L for Pb; 1.6 μg/L for Cd; and 1.0 μg/L for Ni. The result showed that sensitivity was increased 4 times for Pb, 6 times for Ni, and none for Cd. The highest concentration of Pb in Cikapundung River was found 8.0 μg/L. All Ni concentration in water samples were under limit of detection. Method validation was conducted in this study and found that the value of correlation coefficient (r) for Pb, Cd and Ni was 0.9995, 0.9960 and 0.9994, respectively. The recovery value for Pb, Cd and Ni were 112.0, 81.5 and 85.9%, respectively in Cikapundung River, and 119.0, 83.5 and 85.9 %, respectively, in groundwater samples. The value of Relative Standard Deviation (RSD) for Pb, Cd and Ni in Cikapundung River were 2.01, 2.15 and 6.40%, respectively. On the other hand, the value of RSD of Pb, Cd and Ni in groundwater were 2.70, 3.30 and 7.69%, respectively. In conclusion, back-extraction method can be applied as pre-concentration for low concentration of Pb and Ni in river water samples.

  4. Evaluation of a novel method for measurement of intracellular calcium ion concentration in fission yeast.

    Science.gov (United States)

    Ogata, Fumihiko; Satoh, Ryosuke; Kita, Ayako; Sugiura, Reiko; Kawasaki, Naohito

    2017-01-01

    The distribution of metal and metalloid species in each of the cell compartments is termed as "metallome". It is important to elucidate the molecular mechanism underlying the beneficial or toxic effects exerted by a given metal or metalloid on human health. Therefore, we developed a method to measure intracellular metal ion concentration (particularly, intracellular calcium ion) in fission yeast. We evaluated the effects of nitric acid (HNO 3 ), zymolyase, and westase treatment on cytolysis in fission yeast. Moreover, we evaluated the changes in the intracellular calcium ion concentration in fission yeast in response to treatment with/without micafungin. The fission yeast undergoes lysis when treated with 60% HNO 3 , which is simpler and cheaper compared to the other treatments. Additionally, the intracellular calcium ion concentration in 60% HNO 3 -treated fission yeast was determined by inductively coupled plasma atomic emission spectrometry. This study yields significant information pertaining to measurement of the intracellular calcium ion concentration in fission yeast, which is useful for elucidating the physiological or pathological functions of calcium ion in the biological systems. This study is the first step to obtain perspective view on the effect of the metallome in biological systems.

  5. Development of a fast and efficient method for hepatitis A virus concentration from green onion.

    Science.gov (United States)

    Zheng, Yan; Hu, Yuan

    2017-11-01

    Hepatitis A virus (HAV) can cause serious liver disease and even death. HAV outbreaks are associated with the consumption of raw or minimally processed produce, making it a major public health concern. Infections have occurred despite the fact that effective HAV vaccine has been available. Development of a rapid and sensitive HAV detection method is necessary for an investigation of an HAV outbreak. Detection of HAV is complicated by the lack of a reliable culture method. In addition, due to the low infectious dose of HAV, these methods must be very sensitive. Current methods rely on efficient sample preparation and concentration steps followed by sensitive molecular detection techniques. Using green onions which was involved in most recent HAV outbreaks as a representative produce, a method of capturing virus particles was developed using carboxyl-derivatized magnetic beads in this study. Carboxyl beads, like antibody-coated beads or cationic beads, detect HAV at a level as low as 100 pfu/25g of green onions. RNA from virus concentrated in this manner can be released by heat-shock (98°C 5min) for molecular detection without sacrificing sensitivity. Bypassing the RNA extraction procedure saves time and removes multiple manipulation steps, which makes large scale HAV screening possible. In addition, the inclusion of beef extract and pectinase rather than NP40 in the elution buffer improved the HAV liberation from the food matrix over current methods by nearly 10 fold. The method proposed in this study provides a promising tool to improve food risk assessment and protect public health. Published by Elsevier B.V.

  6. Detection of protozoa in water samples by formalin/ether concentration method.

    Science.gov (United States)

    Lora-Suarez, Fabiana; Rivera, Raul; Triviño-Valencia, Jessica; Gomez-Marin, Jorge E

    2016-09-01

    Methods to detect protozoa in water samples are expensive and laborious. We evaluated the formalin/ether concentration method to detect Giardia sp., Cryptosporidium sp. and Toxoplasma in water. In order to test the properties of the method, we spiked water samples with different amounts of each protozoa (0, 10 and 50 cysts or oocysts) in a volume of 10 L of water. Immunofluorescence assay was used for detection of Giardia and Cryptosporidium. Toxoplasma oocysts were identified by morphology. The mean percent of recovery in 10 repetitions of the entire method, in 10 samples spiked with ten parasites and read by three different observers, were for Cryptosporidium 71.3 ± 12, for Giardia 63 ± 10 and for Toxoplasma 91.6 ± 9 and the relative standard deviation of the method was of 17.5, 17.2 and 9.8, respectively. Intraobserver variation as measured by intraclass correlation coefficient, was fair for Toxoplasma, moderate for Cryptosporidium and almost perfect for Giardia. The method was then applied in 77 samples of raw and drinkable water in three different plant of water treatment. Cryptosporidium was found in 28 of 77 samples (36%) and Giardia in 31 of 77 samples (40%). Theses results identified significant differences in treatment process to reduce the presence of Giardia and Cryptosporidium. In conclusion, the formalin ether method to concentrate protozoa in water is a new alternative for low resources countries, where is urgently need to monitor and follow the presence of theses protozoa in drinkable water. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Determination of molybdenum (VI) in sea water with preliminary concentration by the method of ion flotation

    International Nuclear Information System (INIS)

    Andreeva, I. Yu.; Drapchinskaya, O.L.; Lebedeva, L.I.

    1985-01-01

    The purpose of this paper is to assess the feasibility of using the method of ion flotation for the concentration of microamounts of molybdenum (VI) during determination in sea water. The ion flotation method is used for the purification of industrial sewage from the ions of nonferrous metals, including molybdenum (VI) with its content of up to 50 mg/liter. A 1.10 -4 M solution of sodium molybdate in 0.1M NaOH was used. The effect of different factors on the ion flotation process of molybdenum (VI) was investigated: pH of the solution, flotation times, concentrations of surface-active substances (SAS), molybdenum (IV), extraneous salts. Data presented show that the ion flotation method in conjunction with the photometric method of determining molybdenum with brompyrogallol red (BPR) and cetylpridinium chloride (CP) (limit of detection 0.02 micrograms/liter) allows the content of molybdenum (VI) in sea water to be established with sufficient reliability and reproducibility

  8. Concentric Ring Method for generating pollen maps. Quercus as case study.

    Science.gov (United States)

    Oteros, Jose; Valencia, Rosa Mª; Del Río, Sara; Vega, Ana Mª; García-Mozo, Herminia; Galán, Carmen; Gutiérrez, Pablo; Mandrioli, Paolo; Fernández-González, Delia

    2017-01-15

    Mapping pollen concentrations is of great interest to study the health impact and ecological implications or for forestry or agronomical purposes. A deep knowledge about factors affecting airborne pollen is essential for predicting and understanding its dynamics. The present work sought to predict annual Quercus pollen over the Castilla and León region (Central and Northern Spain). Also to understand the relationship between airborne pollen and landscape. Records of Quercus and Quercus pyrenaica pollen types were collected at 13 monitoring sites over a period of 8years. They were analyzed together with land use data applying the Concentric Ring Method (CRM), a technique that we developed to study the relationship between airborne particle concentrations and emission sources in the region. The maximum correlation between the Quercus pollen and forms of vegetation was determined by shrubland and "dehesa" areas. For the specific Qi pyrenaica model (Q. pyrenaica pollen and Q. pyrenaica forest distribution), the maximum influence of emission sources on airborne pollen was observed at 14km from the pollen trap location with some positive correlations up to a distance of 43km. Apart from meteorological behavior, the local features of the region can explain pollen dispersion patterns. The method that we develop here proved to be a powerful tool for multi-source pollen mapping based on land use. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Practical method of calculating time-integrated concentrations at medium and large distances

    International Nuclear Information System (INIS)

    Cagnetti, P.; Ferrara, V.

    1980-01-01

    Previous reports have covered the possibility of calculating time-integrated concentrations (TICs) for a prolonged release, based on concentration estimates for a brief release. This study proposes a simple method of evaluating concentrations in the air at medium and large distances, for a brief release. It is known that the stability of the atmospheric layers close to ground level influence diffusion only over short distances. Beyond some tens of kilometers, as the pollutant cloud progressively reaches higher layers, diffusion is affected by factors other than the stability at ground level, such as wind shear for intermediate distances and the divergence and rotational motion of air masses towards the upper limit of the mesoscale and on the synoptic scale. Using the data available in the literature, expressions for sigmasub(y) and sigmasub(z) are proposed for transfer times corresponding to those for up to distances of several thousand kilometres, for two initial diffusion situations (up to distances of 10 - 20 km), those characterized by stable and neutral conditions respectively. Using this method simple hand calculations can be made for any problem relating to the diffusion of radioactive pollutants over long distances

  10. Determining concentrations of 2-bromoallyl alcohol and dibromopropene in ground water using quantitative methods

    Science.gov (United States)

    Panshin, Sandra Y.

    1997-01-01

    A method for determining levels of 2-bromoallyl alcohol and 2,3-dibromopropene from ground-water samples using liquid/liquid extraction followed by gas chromatography/mass spectrometry is described. Analytes were extracted from the water using three aliquots of dichloromethane. The aliquots were combined and reduced in volume by rotary evaporation followed by evaporation using a nitrogen stream. The extracts were analyzed by capillary-column gas chromatography/mass spectrometry in the full-scan mode. Estimated method detection limits were 30 nanograms per liter for 2-bromoallyl alcohol and 10 nanograms per liter for 2,3-dibromopropene. Recoveries were determined by spiking three matrices at two concentration levels (0.540 and 5.40 micrograms per liter for 2-bromoallyl alcohol; and 0.534 and 5.34micro-grams per liter for dibromopropene). For seven replicates of each matrix at the high concentration level, the mean percent recoveries ranged from 43.9 to 64.9 percent for 2-bromoallyl alcohol, and from 87.5 to 99.3 percent for dibromopropene. At the low concentration level, the mean percent recoveries ranged from 43.8 to 95.2 percent for 2-bromoallyl alcohol, and from 71.3 to 84.9 percent for dibromopropene.

  11. A Comparison of Costal Cartilage Warping Using Oblique Split vs Concentric Carving Methods.

    Science.gov (United States)

    Wilson, Gemma C; Dias, Laura; Faris, Callum

    2017-12-01

    Warping of costal cartilage is well described; however, its strength and abundance still make it a desirable graft material, especially in complex reconstructive rhinoplasty. Despite multiple methods of cartilage harvest, carving, and preimplantation treatment being developed over the years, warp remains a challenging clinical problem. To assess whether the 30° oblique split method of preparing costal cartilage grafts produces less warping of the graft than the current standard of harvesting the central segment of a rib using the concentric carving method. This in vitro cadaveric study evaluated the warping of costal cartilage grafts using the oblique split method with an angle of 30° or the concentric carving method during a 3-month period beginning in December 2014. Millimeters of warp from baseline (at 1 hour) and at 1, 2, and 3 months, measured in the frontal and lateral planes. Among 74 costal cartilage grafts (using the oblique split method with an angle of 30° in 41 and the concentric carving method in 33), the mean amount of warp in the frontal plane was between 1.12 mm (95% CI, 0.96-1.28 mm) and 1.57 mm (95% CI, 0.94-2.20 mm) for the oblique group and between 1.18 mm (95% CI, 0.98-1.38 mm) and 1.29 mm (95% CI, 0.86-1.72 mm) for the concentric group during the 3-month period. There was no statistically significant difference in the frontal plane between the 2 methods at 1 hour (P = .45; 0.10 mm, 95% CI, -0.38 to 0.17 mm), 1 month (P = .32; 0.13 mm, 95% CI, -0.13 to 0.40 mm), 2 months (P = .50; 0.28 mm, 95% CI, -0.55 to 1.11 mm), or 3 months (P = .15; 0.22 mm, 95% CI, -0.08 to 0.52 mm) using the t test, regression analysis, or panel data analysis. Similarly, no significant difference was found in the lateral plane at 1 hour (P = .89; 0.04 mm, 95% CI, -0.49 to 0.56 mm), 1 month (P = .82; 0.07 mm, 95% CI, -0.56 to 0.70 mm), 2 months (P = .29; 0.40 mm, 95% CI, -0.36 to 1.17 mm), or 3 months (P = .63; 0.22 mm, 95% CI, -0.70 to

  12. Fast Measurement of Methanol Concentration in Ionic Liquids by Potential Step Method

    Science.gov (United States)

    Hainstock, Michael L.; Tang, Yijun

    2015-01-01

    The development of direct methanol fuel cells required the attention to the electrolyte. A good electrolyte should not only be ionic conductive but also be crossover resistant. Ionic liquids could be a promising electrolyte for fuel cells. Monitoring methanol was critical in several locations in a direct methanol fuel cell. Conductivity could be used to monitor the methanol content in ionic liquids. The conductivity of 1-butyl-3-methylimidazolium tetrafluoroborate had a linear relationship with the methanol concentration. However, the conductivity was significantly affected by the moisture or water content in the ionic liquid. On the contrary, potential step could be used in sensing methanol in ionic liquids. This method was not affected by the water content. The sampling current at a properly selected sampling time was proportional to the concentration of methanol in 1-butyl-3-methylimidazolium tetrafluoroborate. The linearity still stood even when there was 2.4 M water present in the ionic liquid. PMID:25802522

  13. Fast Measurement of Methanol Concentration in Ionic Liquids by Potential Step Method

    Directory of Open Access Journals (Sweden)

    Michael L. Hainstock

    2015-01-01

    Full Text Available The development of direct methanol fuel cells required the attention to the electrolyte. A good electrolyte should not only be ionic conductive but also be crossover resistant. Ionic liquids could be a promising electrolyte for fuel cells. Monitoring methanol was critical in several locations in a direct methanol fuel cell. Conductivity could be used to monitor the methanol content in ionic liquids. The conductivity of 1-butyl-3-methylimidazolium tetrafluoroborate had a linear relationship with the methanol concentration. However, the conductivity was significantly affected by the moisture or water content in the ionic liquid. On the contrary, potential step could be used in sensing methanol in ionic liquids. This method was not affected by the water content. The sampling current at a properly selected sampling time was proportional to the concentration of methanol in 1-butyl-3-methylimidazolium tetrafluoroborate. The linearity still stood even when there was 2.4 M water present in the ionic liquid.

  14. A standardized method to determine the concentration of extracellular vesicles using tunable resistive pulse sensing.

    Science.gov (United States)

    Vogel, Robert; Coumans, Frank A W; Maltesen, Raluca G; Böing, Anita N; Bonnington, Katherine E; Broekman, Marike L; Broom, Murray F; Buzás, Edit I; Christiansen, Gunna; Hajji, Najat; Kristensen, Søren R; Kuehn, Meta J; Lund, Sigrid M; Maas, Sybren L N; Nieuwland, Rienk; Osteikoetxea, Xabier; Schnoor, Rosalie; Scicluna, Benjamin J; Shambrook, Mitch; de Vrij, Jeroen; Mann, Stephen I; Hill, Andrew F; Pedersen, Shona

    2016-01-01

    Understanding the pathogenic role of extracellular vesicles (EVs) in disease and their potential diagnostic and therapeutic utility is extremely reliant on in-depth quantification, measurement and identification of EV sub-populations. Quantification of EVs has presented several challenges, predominantly due to the small size of vesicles such as exosomes and the availability of various technologies to measure nanosized particles, each technology having its own limitations. A standardized methodology to measure the concentration of extracellular vesicles (EVs) has been developed and tested. The method is based on measuring the EV concentration as a function of a defined size range. Blood plasma EVs are isolated and purified using size exclusion columns (qEV) and consecutively measured with tunable resistive pulse sensing (TRPS). Six independent research groups measured liposome and EV samples with the aim to evaluate the developed methodology. Each group measured identical samples using up to 5 nanopores with 3 repeat measurements per pore. Descriptive statistics and unsupervised multivariate data analysis with principal component analysis (PCA) were used to evaluate reproducibility across the groups and to explore and visualise possible patterns and outliers in EV and liposome data sets. PCA revealed good reproducibility within and between laboratories, with few minor outlying samples. Measured mean liposome (not filtered with qEV) and EV (filtered with qEV) concentrations had coefficients of variance of 23.9% and 52.5%, respectively. The increased variance of the EV concentration measurements could be attributed to the use of qEVs and the polydisperse nature of EVs. The results of this study demonstrate the feasibility of this standardized methodology to facilitate comparable and reproducible EV concentration measurements.

  15. Evaluation of air quality zone classification methods based on ambient air concentration exposure.

    Science.gov (United States)

    Freeman, Brian; McBean, Ed; Gharabaghi, Bahram; Thé, Jesse

    2017-05-01

    Air quality zones are used by regulatory authorities to implement ambient air standards in order to protect human health. Air quality measurements at discrete air monitoring stations are critical tools to determine whether an air quality zone complies with local air quality standards or is noncompliant. This study presents a novel approach for evaluation of air quality zone classification methods by breaking the concentration distribution of a pollutant measured at an air monitoring station into compliance and exceedance probability density functions (PDFs) and then using Monte Carlo analysis with the Central Limit Theorem to estimate long-term exposure. The purpose of this paper is to compare the risk associated with selecting one ambient air classification approach over another by testing the possible exposure an individual living within a zone may face. The chronic daily intake (CDI) is utilized to compare different pollutant exposures over the classification duration of 3 years between two classification methods. Historical data collected from air monitoring stations in Kuwait are used to build representative models of 1-hr NO 2 and 8-hr O 3 within a zone that meets the compliance requirements of each method. The first method, the "3 Strike" method, is a conservative approach based on a winner-take-all approach common with most compliance classification methods, while the second, the 99% Rule method, allows for more robust analyses and incorporates long-term trends. A Monte Carlo analysis is used to model the CDI for each pollutant and each method with the zone at a single station and with multiple stations. The model assumes that the zone is already in compliance with air quality standards over the 3 years under the different classification methodologies. The model shows that while the CDI of the two methods differs by 2.7% over the exposure period for the single station case, the large number of samples taken over the duration period impacts the sensitivity

  16. Lentiviral transgenesis in mice via a simple method of viral concentration.

    Science.gov (United States)

    Cheng, Pei-Hsun; Chang, Yu-Fan; Mao, Su-Han; Lin, Hsiu-Lien; Chen, Chuan-Mu; Yang, Shang-Hsun

    2016-10-01

    Transgenic animals are important in vivo models for biological research. However, low transgenic rates are commonly reported in the literature. Lentiviral transgenesis is a promising method that has greater efficiency with regard to generating transgenic animals, although the transgenic rate of this approach is highly dependent on different transgenes and concentrated lentiviruses. In this study, we modified a method to concentrate lentiviruses using a table centrifuge, commonly available in most laboratories, and carried out analysis of the transgenic efficiency in mice. Based on 26 individual constructs and 627 live pups, we found that the overall transgenic rate was more than 30%, which is higher than obtained with pronuclear microinjection. In addition, we did not find any significant differences in transgenic efficiency when the size of inserts was less than 5000 bp. These results not only show that our modified method can successfully generate transgenic mice but also suggest that this approach could be generally applied to different constructs when the size of inserts is less than 5000 bp. It is anticipated that the results of this study can help encourage the wider laboratory use of lentiviral transgenesis in mice. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. A method of batch-purifying microalgae with multiple antibiotics at extremely high concentrations

    Science.gov (United States)

    Han, Jichang; Wang, Song; Zhang, Lin; Yang, Guanpin; Zhao, Lu; Pan, Kehou

    2016-01-01

    Axenic microalgal strains are highly valued in diverse microalgal studies and applications. Antibiotics, alone or in combination, are often used to avoid bacterial contamination during microalgal isolation and culture. In our preliminary trials, we found that many microalgae ceased growing in antibiotics at extremely high concentrations but could resume growth quickly when returned to an antibiotics-free liquid medium and formed colonies when spread on a solid medium. We developed a simple and highly efficient method of obtaining axenic microalgal cultures based on this observation. First, microalgal strains of different species or strains were treated with a mixture of ampicillin, gentamycin sulfate, kanamycin, neomycin and streptomycin (each at a concentration of 600 mg/L) for 3 days; they were then transferred to antibiotics-free medium for 5 days; and finally they were spread on solid f/2 media to allow algal colonies to form. With this method, five strains of Nannochloropsis sp. (Eustigmatophyceae), two strains of Cylindrotheca sp. (Bacillariophyceae), two strains of Tetraselmis sp. (Chlorodendrophyceae) and one strain of Amphikrikos sp. (Trebouxiophyceae) were purified successfully. The method shows promise for batch-purifying microalgal cultures.

  18. Sediment acoustic index method for computing continuous suspended-sediment concentrations

    Science.gov (United States)

    Landers, Mark N.; Straub, Timothy D.; Wood, Molly S.; Domanski, Marian M.

    2016-07-11

    Suspended-sediment characteristics can be computed using acoustic indices derived from acoustic Doppler velocity meter (ADVM) backscatter data. The sediment acoustic index method applied in these types of studies can be used to more accurately and cost-effectively provide time-series estimates of suspended-sediment concentration and load, which is essential for informed solutions to many sediment-related environmental, engineering, and agricultural concerns. Advantages of this approach over other sediment surrogate methods include: (1) better representation of cross-sectional conditions from large measurement volumes, compared to other surrogate instruments that measure data at a single point; (2) high temporal resolution of collected data; (3) data integrity when biofouling is present; and (4) less rating curve hysteresis compared to streamflow as a surrogate. An additional advantage of this technique is the potential expansion of monitoring suspended-sediment concentrations at sites with existing ADVMs used in streamflow velocity monitoring. This report provides much-needed standard techniques for sediment acoustic index methods to help ensure accurate and comparable documented results.

  19. Detection of enteric viruses in activated sludge by feasible concentration methods.

    Science.gov (United States)

    Prado, Tatiana; Gaspar, Ana Maria Coimbra; Miagostovich, Marize Pereira

    2014-01-01

    Human enteric viruses are responsible to cause several diseases, including gastroenteritis and hepatitis, and can be present in high amounts in sewage sludge. This study compared virus recovery efficiency of two feasible concentration methods used for detecting human adenovirus (HAdV), rotavirus species A (RV-A), norovirus genogroup II (NoV GII) and hepatitis A virus (HAV) in sewage sludge from an activated sludge process. Twelve sewage sludge samples were collected bi-monthly from January to July, 2011. Ultracentrifugation was compared with a simplified protocol based on beef extract elution for recovering enteric viruses. Viruses were quantified by quantitative real-time PCR assays and virus recovery efficiency and limits of detection were determined. Methods showed mean recovery rates lower than 7.5%, presenting critical limits of detection (higher than 10(2) - 10(3) genome copies - GC L(-1) for all viruses analyzed). Nevertheless, HAdV were detected in 90% of the analyzed sewage sludge samples (range: 1.8 × 10(4) to 1.1 × 10(5) GC L(-1)), followed by RV-A and NoV (both in 50%) and HAV (8%). Results suggesting that activated sludge is contaminated with high viral loads and HAdV are widely disseminated in these samples. The low virus recovery rates achieved, especially for HAV, indicate that other feasible concentration methods could be developed to improve virus recovery efficiency in these environmental matrices.

  20. A rapid cleanup method for the isolation and concentration of pyrrolizidine alkaloids in comfrey root.

    Science.gov (United States)

    Gray, Dean E; Porter, Andrew; O'Neill, Terry; Harris, Roger K; Rottinghaus, George E

    2004-01-01

    Preparations from comfrey (Symphytum officinale and S. x uplandicum) root and leaf contain varying levels of the hepatotoxic pyrrolizidine alkaloids (PAs). Reference compounds for comfrey are not commercially available, and there is currently no rapid extraction or analytical method capable of determining low levels in raw materials or as adulterants in commercially available extracts. A solid-phase extraction (SPE) method was developed using an Ergosil cleanup column that specifically binds the PAs. With this method, powdered comfrey root was extracted by sonication and shaking with basic chloroform. The extract was applied to the cleanup column under vacuum, washed with 2 mL acetone-chloroform (8 + 2, v/v) followed by 2 mL petroleum ether to remove excess chloroform. The column was dried under vacuum, and the PAs were eluted with 2 successive 1 mL aliquots methanol. Percent recoveries of the PAs following Ergosil SPE had an overall average of 96.8%, with RSD of 3.8% over a range of 1.0 to 25.0 g extracted in 100 mL. Average precision of the method (n = 3 over 4 extraction concentrations) gave an overall RSD of 6.0% for the 5 alkaloids, with a range of 0.8% (5 g in 100 mL) to 11.2% (25 g in 100 mL). Recovery optimization testing showed that 1.0 g comfrey root extracted in 100 mL yielded the greatest recovery (% dry weight) of the PAs, with an extraction efficiency and accuracy of 94.2%, and RSD of 1.7% (n = 9). The unique properties of the Ergosil cleanup column provide rapid sample cleanup, volume reduction, and concentration of PAs from comfrey extracts, and allow the eluant to be analyzed directly by traditional chromatographic methods.

  1. Evaluation of the capillary electrophoresis method for measurement of immunoglobulin concentration in ewe colostrum.

    Science.gov (United States)

    Lopreiato, V; Ceniti, C; Trimboli, F; Fratto, E; Marotta, M; Britti, D; Morittu, V M

    2017-08-01

    Capillary electrophoresis (CE) is a technique routinely used in clinical laboratories that allows the separation and quantification of blood serum proteins in a rapid, precise, accurate, and inexpensive manner. Recently, CE has been proposed to separate and measure colostral proteins, but an evaluation of the agreement between CE and radial immunodiffusion (RID) method, currently used to quantify IgG in colostrum, is still lacking. The purpose of this study was to test the ability of a CE instrument, normally used in blood serum protein analysis, to realize the correct quantification of total Ig concentration in ewe colostrum, using RID assay as reference. Colostrum samples (n = 68) were collected from 35 multiparous Sarda ewes at first milking (n = 33) and at 24 h postpartum (n = 35). The mean ± standard deviation of IgG concentration measured by RID and whey colostrum total Ig concentration measured by CE were 54.76 ± 41.82 g/L and 54.70 ± 41.43 g/L, respectively. Lin's concordance correlation coefficient (r = 0.993; 95% confidence interval = 0.989 to 0.996) and linear regression analysis results (RID = 1.0022CE - 0.063; R 2 = 0.986) showed an excellent agreement between these 2 methods. Bland-Altman analysis confirmed that CE method can be a suitable alternative to RID: the mean of the differences between CE and RID was -0.055 ± 4.95 g/L (95% confidence interval = -1.25 to 1.14 g/L) and the agreement limits were -9.75 to 9.60 g/L (low limit 95% confidence interval = -11.82 to -7.68 g/L; high limit 95% confidence interval = 7.57 to 11.72 g/L). In conclusion, the current study indicates that CE method may be a reliable tool for the quantification of the total Ig concentration in ewe colostrum. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  2. Simple, cost effective method for determination of phosphorus in uranium ore concentrate

    International Nuclear Information System (INIS)

    Misra, U.B.; Ramamurty, Vasantha; Dutta, M.; Balaji Rao, Y.; Subba Rao, Y.

    2015-01-01

    In this paper determination of phosphate as phosphorus in uranium ore concentrate has been described. The method used is spectrophotometric determination of phosphorus as phospho-molybdenum blue complex. As uranyl ion do not absorb in 600-900 nm range of visible region in the present medium, the phosphomolybdenum blue complex formation which is having maximum absorbance at 825 nm is exploited for determination of phosphorus. The molar absorptivity coefficient with and without the presence of uranium matrix are 2.6048 x 10 4 and 2.6730 x 10 4 lmol -1 cm -1 . The effect of matrix is not evident from the experiment carried out. (author)

  3. Use of nuclear methods for the analysis of materials and the determination of concentration profiles

    International Nuclear Information System (INIS)

    Darras, R.

    1976-01-01

    The possibilities of the activation analysis and nuclear reaction analysis are presented. These methods allow the oligo-elements and impurities (in trace amounts) to be determined in materials with accuracy and a high sensitivity. They can also be applied to the determination of major elements in a small amount of materials. Surface analysis and concentration profile determination are possible when the nature and energy of the incident particles are judiciously selected. Exemples of analysis of steels, pure iron and refractories are given [fr

  4. Applicability of Stokes method for measuring viscosity of mixtures with concentration gradient

    Directory of Open Access Journals (Sweden)

    César Medina

    2017-12-01

    Full Text Available After measuring density and viscosity of a mixture of glycerin and water contained in a vertical pipe, a variation of these properties according to depth is observed. These gradients are typical of non-equilibrium states related to the lower density of water and the fact that relatively long times are necessary to achieve homogeneity. In the same pipe, the falling velocity of five little spheres is measured as a function of depth, and then a numerical fit is performed which agrees very well with experimental data. Based on the generalization of these results, the applicability of Stokes method is discussed for measuring viscosity of mixtures with a concentration gradient.

  5. Materials, methods and devices to detect and quantify water vapor concentrations in an atmosphere

    Science.gov (United States)

    Allendorf, Mark D; Robinson, Alex L

    2014-12-09

    We have demonstrated that a surface acoustic wave (SAW) sensor coated with a nanoporous framework material (NFM) film can perform ultrasensitive water vapor detection at concentrations in air from 0.05 to 12,000 ppmv at 1 atmosphere pressure. The method is extendable to other MEMS-based sensors, such as microcantilevers, or to quartz crystal microbalance sensors. We identify a specific NFM that provides high sensitivity and selectivity to water vapor. However, our approach is generalizable to detection of other species using NFM to provide sensitivity and selectivity.

  6. Engineering Bacteria to Search for Specific Concentrations of Molecules by a Systematic Synthetic Biology Design Method.

    Science.gov (United States)

    Tien, Shin-Ming; Hsu, Chih-Yuan; Chen, Bor-Sen

    2016-01-01

    Bacteria navigate environments full of various chemicals to seek favorable places for survival by controlling the flagella's rotation using a complicated signal transduction pathway. By influencing the pathway, bacteria can be engineered to search for specific molecules, which has great potential for application to biomedicine and bioremediation. In this study, genetic circuits were constructed to make bacteria search for a specific molecule at particular concentrations in their environment through a synthetic biology method. In addition, by replacing the "brake component" in the synthetic circuit with some specific sensitivities, the bacteria can be engineered to locate areas containing specific concentrations of the molecule. Measured by the swarm assay qualitatively and microfluidic techniques quantitatively, the characteristics of each "brake component" were identified and represented by a mathematical model. Furthermore, we established another mathematical model to anticipate the characteristics of the "brake component". Based on this model, an abundant component library can be established to provide adequate component selection for different searching conditions without identifying all components individually. Finally, a systematic design procedure was proposed. Following this systematic procedure, one can design a genetic circuit for bacteria to rapidly search for and locate different concentrations of particular molecules by selecting the most adequate "brake component" in the library. Moreover, following simple procedures, one can also establish an exclusive component library suitable for other cultivated environments, promoter systems, or bacterial strains.

  7. Investigation of Intracellular Free Ca2+ Concentration Dynamics with Fluorescence Methods

    Directory of Open Access Journals (Sweden)

    Figen Cicek

    2016-09-01

    Full Text Available Most of the extracellular stimulus arrive to the cell membrane result with the increase in cytoplasmic free Ca2+ concentration [Ca2+]i. Because of the huge Ca2+ concentration differences between the cytoplasm ( and #8776;10-7 M and extracellular fluid and endoplasmic reticulum (ER - which is the major Ca2+ storage organelle in especially non electrically excitable cells ( and #8776;10-3 M, a large electro-chemical gradient repel Ca2+ to the plasma or ER. Therefore a signal which temporarily opens Ca2+ channels, induce a fast influx of Ca2+ through the cytosol and increase the its concentration about 10-20 fold. At this organization free Ca2+ functions as a intracellular signalling molecule and a second messenger. In this way many intracellular signalling proteins activated and cellular functions like gene expression, secretion, cell proliferation and division, apoptosis, and also myocyte contraction, endocrine cell degranulation and neuronal transmission are regulated. Thus, the key role of Ca2+ in many intracellular process, makes the dynamic measurements necessary for an understanding of the signalling mechanisms. Fluorescence imaging techniques make possible of monitoring the spatiotemporal Ca2+ response patterns in cytoplasm. In the last decades, especially their ease of loading, and minimum manipulations to the cell homeostasis, make these techniques unique with respect to the other methods. [Archives Medical Review Journal 2016; 25(3.000: 319-334

  8. Improvable method for Halon 1301 concentration measurement based on infrared absorption

    Science.gov (United States)

    Hu, Yang; Lu, Song; Guan, Yu

    2015-09-01

    Halon 1301 has attached much interest because of its pervasive use as an effective fire suppressant agent in aircraft related fires, and the study of fire suppressant agent concentration measurement is especially of interest. In this work, a Halon 1301 concentration measurement method based on the Beer-Lambert law is developed. IR light is transmitted through mixed gas, and the light intensity with and without the agent present is measured. The intensity ratio is a function of the volume percentage of Halon 1301, and the voltage output of the detector is proportional to light intensity. As such, the relationship between the volume percentage and voltage ratio can be established. The concentration measurement system shows a relative error of the system less than ±2.50%, and a full scale error within 1.20%. This work also discusses the effect of temperature and relative humidity (RH) on the calibration. The experimental results of voltage ratio versus Halon 1301 volume percentage relationship show that the voltage ratio drops significantly as temperature rises from 25 to 100 °C, and it decreases as RH rises from 0% to 100%.

  9. Engineering Bacteria to Search for Specific Concentrations of Molecules by a Systematic Synthetic Biology Design Method.

    Directory of Open Access Journals (Sweden)

    Shin-Ming Tien

    Full Text Available Bacteria navigate environments full of various chemicals to seek favorable places for survival by controlling the flagella's rotation using a complicated signal transduction pathway. By influencing the pathway, bacteria can be engineered to search for specific molecules, which has great potential for application to biomedicine and bioremediation. In this study, genetic circuits were constructed to make bacteria search for a specific molecule at particular concentrations in their environment through a synthetic biology method. In addition, by replacing the "brake component" in the synthetic circuit with some specific sensitivities, the bacteria can be engineered to locate areas containing specific concentrations of the molecule. Measured by the swarm assay qualitatively and microfluidic techniques quantitatively, the characteristics of each "brake component" were identified and represented by a mathematical model. Furthermore, we established another mathematical model to anticipate the characteristics of the "brake component". Based on this model, an abundant component library can be established to provide adequate component selection for different searching conditions without identifying all components individually. Finally, a systematic design procedure was proposed. Following this systematic procedure, one can design a genetic circuit for bacteria to rapidly search for and locate different concentrations of particular molecules by selecting the most adequate "brake component" in the library. Moreover, following simple procedures, one can also establish an exclusive component library suitable for other cultivated environments, promoter systems, or bacterial strains.

  10. A Spectrometric Method for Hydrogen Peroxide Concentration Measurement with a Reusable and Cost-Efficient Sensor

    Directory of Open Access Journals (Sweden)

    Cheng-Chih Hsu

    2015-10-01

    Full Text Available In this study we developed a low cost sensor for measuring the concentration of hydrogen peroxide (H2O2 in liquids utilizing a spectrometric method. The sensor was tested using various concentrations of a peroxidase enzyme immobilized on a glass substrate. H2O2 can be catalyzed by peroxidase and converted into water and oxygen. The reagent 4-amino-phenazone takes up oxygen together with phenol to form a colored product that has absorption peaks at 510 nm and 450 nm. The transmission intensity is strongly related to the hydrogen peroxide concentration, so can be used for quantitative analysis. The measurement range for hydrogen peroxide is from 5 × 10−5% to 1 × 10−3% (0.5 ppm to 10 ppm and the results show high linearity. This device can achieve a sensitivity and resolution of 41,400 (photon count/% and 3.49 × 10−5% (0.35 ppm, respectively. The response time of the sensor is less than 3 min and the sensor can be reused for 10 applications with similar performance.

  11. [Standardization of a method for concentration and detection of enteric viruses from drinking water].

    Science.gov (United States)

    Peláez, Dioselina; Rodríguez, Johanna Alexandra; Rocha, Elva Lucía; Rey, Gloria Janeth

    2010-01-01

    Enteric viruses have been implicated in acute diarrheal disease, food-borne disease, hepatitis A and meningitis outbreaks, in which water was the vehicle of transmission. A concentration method was standardized for the detection of enteric viruses in drinking water. Twenty liters of water were concentrated to 6 ml by filtration and tangential ultrafiltration. Viral solutions of 20 L each were prepared at 1, 10, 50 and 100 TCID50 of Sabin poliovirus type 1 as positive controls. Viral particles were recovered by tissue culture and detected by conventional polymerase chain reaction (PCR), according to the international standards recommended by the Enterovirus Laboratory at the Centers for Disease Control and Prevention, Atlanta, GA. All positive controls showed cytopathic effect on L20B and RD cells and were amplified by conventional PCR directly from samples. Negative controls did not show any amplification or viral cytopathic effect. Tangential ultrafiltration for concentrating viruses proved to be a fast, efficient recovery and reproducible. It has the advantage of allowing the detection (at the 1 TCID50 level) and identification of viruses by RT-PCR and the demonstration of viral infectivity by tissue culture.

  12. 40 CFR Table 2 of Subpart Bbbbbbb... - Initial Compliance Demonstration Methods With the Emission Reduction and PM Concentration...

    Science.gov (United States)

    2010-07-01

    ... Methods With the Emission Reduction and PM Concentration Requirements 2 Table 2 of Subpart BBBBBBB of Part... Concentration Requirements If you are demonstrating compliance with the * * * You must demonstrate initial... (98 percent for new sources) or an outlet concentration of 0.03 gr/dscf or less. a. Perform a PM...

  13. Development of the interfacial area concentration measurement method using a five sensor conductivity probe

    International Nuclear Information System (INIS)

    Euh, Dong Jin; Yun, Byong Jo; Song, Chul Hwa; Kwon, Tae Soon; Chung, Moon Ki; Lee, Un Chul

    2000-01-01

    The interfacial area concentration(IAC) is one of the most important parameters in the two-fluid model for two-phase flow analysis. The IAE can be measured by a local conductivity probe method that uses the difference of conductivity between water and air/steam. The number of sensors in the conductivity probe may be differently chosen by considering the flow regime of two-phase flow. The four sensor conductivity probe method predicts the IAC without any assumptions of the bubble shape. The local IAC can be obtained by measuring the three dimensional velocity vector elements at the measuring point, and the directional cosines of the sensors. The five sensor conductivity probe method proposed in this study is based on the four sensor probe method. With the five sensor probe, the local IAC for a given referred measuring area of the probe can be predicted more exactly than the four sensor prober. In this paper, the mathematical approach of the five sensor probe method for measuring the IAC is described, and a numerical simulation is carried out for ideal cap bubbles of which the sizes and locations are determined by a random number generator

  14. A surrogate method for comparison analysis of salivary concentrations of Xylitol-containing products

    Directory of Open Access Journals (Sweden)

    Zhou Lingmei

    2008-02-01

    Full Text Available Abstract Background Xylitol chewing gum has been shown to reduce Streptococcus mutans levels and decay. Two studies examined the presence and time course of salivary xylitol concentrations delivered via xylitol-containing pellet gum and compared them to other xylitol-containing products. Methods A within-subjects design was used for both studies. Study 1, adults (N = 15 received three xylitol-containing products (pellet gum (2.6 g, gummy bears (2.6 g, and commercially available stick gum (Koolerz, 3.0 g; Study 2, a second group of adults (N = 15 received three xylitol-containing products (pellet gum, gummy bears, and a 33% xylitol syrup (2.67 g. For both studies subjects consumed one xylitol product per visit with a 7-day washout between each product. A standardized protocol was followed for each product visit. Product order was randomly determined at the initial visit. Saliva samples (0.5 mL to 1.0 mL were collected at baseline and up to 10 time points (~16 min in length after product consumption initiated. Concentration of xylitol in saliva samples was analyzed using high-performance liquid chromatography. Area under the curve (AUC for determining the average xylitol concentration in saliva over the total sampling period was calculated for each product. Results In both studies all three xylitol products (Study 1: pellet gum, gummy bears, and stick gum; Study 2: pellet gum, gummy bears, and syrup had similar time curves with two xylitol concentration peaks during the sampling period. Study 1 had its highest mean peaks at the 4 min sampling point while Study 2 had its highest mean peaks between 13 to 16 minutes. Salivary xylitol levels returned to baseline at about 18 minutes for all forms tested. Additionally, for both studies the total AUC for the xylitol products were similar compared to the pellet gum (Study 1: pellet gum – 51.3 μg.min/mL, gummy bears – 59.6 μg.min/mL, and stick gum – 46.4 μg.min/mL; Study 2: pellet gum – 63.0

  15. A development and integration of the concentration database for relative method, k0 method and absolute method in instrumental neutron activation analysis using Microsoft Access

    International Nuclear Information System (INIS)

    Hoh Siew Sin

    2012-01-01

    Instrumental Neutron Activation Analysis (INAA) is offen used to determine and calculate the concentration of an element in the sample by the National University of Malaysia, especially students of Nuclear Science Program. The lack of a database service leads consumers to take longer time to calculate the concentration of an element in the sample. This is because we are more dependent on software that is developed by foreign researchers which are costly. To overcome this problem, a study has been carried out to build an INAA database software. The objective of this study is to build a database software that help the users of INAA in Relative Method and Absolute Method for calculating the element concentration in the sample using Microsoft Excel 2010 and Microsoft Access 2010. The study also integrates k 0 data, k 0 Concent and k 0 -Westcott to execute and complete the system. After the integration, a study was conducted to test the effectiveness of the database software by comparing the concentrations between the experiments and in the database. Triple Bare Monitor Zr-Au and Cr-Mo-Au were used in Abs-INAA as monitor to determine the thermal to epithermal neutron flux ratio (f). Calculations involved in determining the concentration are the net peak area (N p ), the measurement time (t m ), the irradiation time (t irr ), k-factor (k), thermal to epithermal neutron flux ratio (f), the parameters of the neutron flux distribution epithermal (α) and detection efficiency (ε p ). For Com-INAA databases, reference material IAEA-375 Soil was used to calculate the concentration of elements in the sample. CRM, SRM are also used in this database. After the INAA database integration, a verification process was to examine the effectiveness of the Abs-INAA was carried out by comparing the sample concentration between the in database and the experiment. The result of the experimental concentration value of INAA database software performed with high accuracy and precision. ICC

  16. Toxicant- and response-specific comparisons of statistical methods for estimating effective concentrations.

    Science.gov (United States)

    Hughes, M R; Bailer, A J; Denton, D L

    2001-06-01

    Standard U.S. Environmental Protection Agency (U.S. EPA) statistical analyses of whole effluent toxicity tests involve the estimation of the concentration associated with a specified level of inhibition relative to control responses. Current U.S. EPA estimation methods (linear interpolation or probit-based methods) are compared to a recently developed parametric regression-based estimator, the relative inhibition concentration estimator RIp. The RIp estimation technique, with level of inhibition p = 25%, is applied to a series of chronic toxicity test data from a U.S. EPA Region 9 database of reference toxicity tests. Tests on marine species are conducted with one reference toxicant, while the freshwater tests are conducted with several reference toxicants. While the U.S. EPA estimators and the RIp estimator are highly correlated for red abalone larval shell development, the degree of correlation for fathead minnow responses varies with reference toxicant tested. The strength of the relationship between the RIp and the standard U.S. EPA estimators varies as a function of the reference toxicant. Correlations range between 0.67 and 0.99. For all biological responses included in this evaluation (fathead minnow growth or survival and red abalone larval development), experiments occurred where the RIp is estimable, while the standard U.S. EPA estimators are not. Nonestimability of the standard EPA methods appears to be related, in part, to the failure of models to account for enhanced responses, such as a hormesis effect prior to toxicity being manifest. The ability to account for such enhanced responses is a strength of the RIp method. Finally, a variance component analysis suggests that lab-to-lab variability is relatively low for the red abalone but relatively high for the fathead minnow.

  17. A method for tissue extraction and determination of prostate concentrations of endogenous androgens by radioimmunoassay

    International Nuclear Information System (INIS)

    Albert, J.; Geller, J.; Geller, S.; Lopez, D.

    1976-01-01

    A method for simultaneously determining concentrations of major androgens in prostate has been developed. Extraction techniques used to isolate the androgens from minced tissue include homogenization with high-speed blades in Delsal's solvent mixture, adsorption to silica gel, followed by column and one thin-layer chromatography (TLC). Radioimmunoassays (RIA) of small aliquots of TLC eluates are used to quantitate picogram amounts of 5α-dihydrotestosterone (DHT) and 5α-androstanediols (Diol) and to estimate testosterone (T) and androstenedione (Ad). Contamination of blanks was reduced to RIA sensitivity limits primarily by treatment of glassware in a self-cleaning oven. The specificity of the method for each androgen was established by TLC separations of known prostate metabolites, antisera specificities, and parallelism of sample aliquots to androgen RIA standards. The overall precision, in terms of coefficients of variation, was 21% for DHT and 24% for Diol. T and Ad could not be measured with acceptable precision because their very low concentrations in prostate (<=0.5 ng/g tissue) were less than RIA sensitivity limits. Accuracy studies indicated recoveries ranging from 96% for Diol to 121% for DHT. In human benign hypertrophic prostate tissue, DHT averaged 153 ng/g soluble protein (5.8 ng/g tissue) which was 17 times higher than values obtained in human spleen and kidney; Diol in prostate showed no consistent differences from values noted in kidney or spleen

  18. A method for estimating radioactive cesium concentrations in cattle blood using urine samples.

    Science.gov (United States)

    Sato, Itaru; Yamagishi, Ryoma; Sasaki, Jun; Satoh, Hiroshi; Miura, Kiyoshi; Kikuchi, Kaoru; Otani, Kumiko; Okada, Keiji

    2017-12-01

    In the region contaminated by the Fukushima nuclear accident, radioactive contamination of live cattle should be checked before slaughter. In this study, we establish a precise method for estimating radioactive cesium concentrations in cattle blood using urine samples. Blood and urine samples were collected from a total of 71 cattle on two farms in the 'difficult-to-return zone'. Urine 137 Cs, specific gravity, electrical conductivity, pH, sodium, potassium, calcium, and creatinine were measured and various estimation methods for blood 137 Cs were tested. The average error rate of the estimation was 54.2% without correction. Correcting for urine creatinine, specific gravity, electrical conductivity, or potassium improved the precision of the estimation. Correcting for specific gravity using the following formula gave the most precise estimate (average error rate = 16.9%): [blood 137 Cs] = [urinary 137 Cs]/([specific gravity] - 1)/329. Urine samples are faster to measure than blood samples because urine can be obtained in larger quantities and has a higher 137 Cs concentration than blood. These advantages of urine and the estimation precision demonstrated in our study, indicate that estimation of blood 137 Cs using urine samples is a practical means of monitoring radioactive contamination in live cattle. © 2017 Japanese Society of Animal Science.

  19. A fluorescence anisotropy method for measuring protein concentration in complex cell culture media.

    Science.gov (United States)

    Groza, Radu Constantin; Calvet, Amandine; Ryder, Alan G

    2014-04-22

    The rapid, quantitative analysis of the complex cell culture media used in biopharmaceutical manufacturing is of critical importance. Requirements for cell culture media composition profiling, or changes in specific analyte concentrations (e.g. amino acids in the media or product protein in the bioprocess broth) often necessitate the use of complicated analytical methods and extensive sample handling. Rapid spectroscopic methods like multi-dimensional fluorescence (MDF) spectroscopy have been successfully applied for the routine determination of compositional changes in cell culture media and bioprocess broths. Quantifying macromolecules in cell culture media is a specific challenge as there is a need to implement measurements rapidly on the prepared media. However, the use of standard fluorescence spectroscopy is complicated by the emission overlap from many media components. Here, we demonstrate how combining anisotropy measurements with standard total synchronous fluorescence spectroscopy (TSFS) provides a rapid, accurate quantitation method for cell culture media. Anisotropy provides emission resolution between large and small fluorophores while TSFS provides a robust measurement space. Model cell culture media was prepared using yeastolate (2.5 mg mL(-1)) spiked with bovine serum albumin (0 to 5 mg mL(-1)). Using this method, protein emission is clearly discriminated from background yeastolate emission, allowing for accurate bovine serum albumin (BSA) quantification over a 0.1 to 4.0 mg mL(-1) range with a limit of detection (LOD) of 13.8 μg mL(-1). Copyright © 2014. Published by Elsevier B.V.

  20. Method of manufacturing large dish reflectors for a solar concentrator apparatus

    Science.gov (United States)

    Angel, Roger P [Tucson, AZ; Olbert, Blain H [Tucson, AZ

    2011-12-27

    A method of manufacturing monolithic glass reflectors for concentrating sunlight in a solar energy system is disclosed. The method of manufacturing allows large monolithic glass reflectors to be made from float glass in order to realize significant cost savings on the total system cost for a solar energy system. The method of manufacture includes steps of heating a sheet of float glass positioned over a concave mold until the sheet of glass sags and stretches to conform to the shape of the mold. The edges of the dish-shaped glass are rolled for structural stiffening around the periphery. The dish-shaped glass is then silvered to create a dish-shaped mirror that reflects solar radiation to a focus. The surface of the mold that contacts the float glass preferably has a grooved surface profile comprising a plurality of cusps and concave valleys. This grooved profile minimizes the contact area and marring of the specular glass surface, reduces parasitic heat transfer into the mold and increases mold lifetime. The disclosed method of manufacture is capable of high production rates sufficiently fast to accommodate the output of a conventional float glass production line so that monolithic glass reflectors can be produced as quickly as a float glass production can make sheets of float glass to be used in the process.

  1. Kinetic Analysis of Parallel-Consecutive First-Order Reactions with a Reversible Step: Concentration-Time Integrals Method

    Science.gov (United States)

    Mucientes, A. E.; de la Pena, M. A.

    2009-01-01

    The concentration-time integrals method has been used to solve kinetic equations of parallel-consecutive first-order reactions with a reversible step. This method involves the determination of the area under the curve for the concentration of a given species against time. Computer techniques are used to integrate experimental curves and the method…

  2. New instruments and methods for measuring the concentration of radioactive products in the atmosphere

    International Nuclear Information System (INIS)

    Jehanno, C.; Blanc, A.; Lallemant, C.; Roux, G.

    1959-01-01

    Different recorders for radioactive aerosols have been developed for measuring the pollution of the atmosphere in laboratories or the external atmosphere. EAR 600. - Allows continuous measurement, instantaneously and 3 to 10 hours after sampling, of concentrations of α or β emitting aerosols varying between some 10 -11 and some 10 -8 curie per cubic metre of air. EAR 800. - Allows continuous measurement of concentration of α emitting aerosols varying between 10 -11 and 10 -5 curie per cubic metre of air and concentration of β emitting aerosols from 10 -11 to 10 -1 curie per cubic metre of air. EAR Plutonium. - Allows detection after several minutes of 1000 MPD (2 x 10 -9 curie par cubic metre), and after 8 hours 1 MPD (2 x 10 -12 curie per cubic metre). Two methods are used to separate the activity due to plutonium from that due to the descendants of radon and thoron: a) by amplitude discrimination, b) by RaC-RaC' and ThC-ThC' (α β ) coincidences. SP4. This system, mounted on a jeep, allows the measurement of irradiation produced on the ground by the smoke from the piles. The sensitivity is 5μR/h. A.D.I.R. - This autonomous and portable instrument is designed for the instantaneous measurement of the radon content of the atmosphere in mines. It allows the measurement of contents in air varying between 0.4 and 400 x 10 -10 curie per litre of air (0.4 and 400 MPD). The measurement of radioactive fall-out is carried out after collection of this activity by a special rain gauge which comprises an adhesive surface and a tube containing ion exchange resins. The radioactivity of the fall-out varies between some 10 -9 and some 10 -7 curie per square metre per month. Concentrations in fission products of the atmosphere are measured after collecting on filter paper. Concentrations measured in air at ground level vary between 10 -13 and 10 -12 curie per cubic metre. (author) [fr

  3. Simulating the growth process of aromatic polyamide layer by monomer concentration controlling method

    International Nuclear Information System (INIS)

    Jin, Yan; Liang, Songmiao; Wu, Zongce; Cai, Zhiqi; Zhao, Ning

    2014-01-01

    Highlights: • A concentration controlling method to simulate the growth process of polyamide layer was developed. • The surface structure features and properties of polyamide layer at its different growth stages were systematically investigated. • Structure transition from spherical aggregator to leaf-like to typical ridge-and-valley was observed. • The performance of RO membrane is closely related to the structure of polyamide. - Abstract: With the wide distribution and gradual increase of TMC concentration (C TMC ) from 1 × 10 −4 wt% to 2.5 × 10 −1 wt%, the main purpose of this work is to simulate the surface structure and properties of polyamide layer of reverse osmosis membranes at its different growth stage. The surface structure and properties of the resulted membranes were then characterized by atomic force microscopy (AFM), scanning electron microscope (SEM), attenuated total reflectance infrared (ATR-IR) spectroscopy, drop shape analysis system and electrokinetic analyzer. The structure growth of polyamide layer underwent in turn three different stages including spherical aggregator, leaf-like and typical ridge-valley structure. Spherical aggregator is the intrinsic structure in the inner layer of polyamide while leaf-like structure is transitional on the outmost polyamide layer. Furthermore, to clarify the effect of the structure change on the properties of polyamide layer, contact angle and zeta potential in the surface of polyamide layer were studied. Hydrophilic surface of polyamide layer is accessible at higher TMC concentration because of the presence of negative charged groups. Performances of the membranes were further measured with an emphasis on studying its structure–performance relationship during the growth process of polyamide layer

  4. A systematic method of interconnection optimization for dense-array concentrator photovoltaic system.

    Science.gov (United States)

    Siaw, Fei-Lu; Chong, Kok-Keong

    2013-01-01

    This paper presents a new systematic approach to analyze all possible array configurations in order to determine the most optimal dense-array configuration for concentrator photovoltaic (CPV) systems. The proposed method is fast, simple, reasonably accurate, and very useful as a preliminary study before constructing a dense-array CPV panel. Using measured flux distribution data, each CPV cells' voltage and current values at three critical points which are at short-circuit, open-circuit, and maximum power point are determined. From there, an algorithm groups the cells into basic modules. The next step is I-V curve prediction, to find the maximum output power of each array configuration. As a case study, twenty different I-V predictions are made for a prototype of nonimaging planar concentrator, and the array configuration that yields the highest output power is determined. The result is then verified by assembling and testing of an actual dense-array on the prototype. It was found that the I-V curve closely resembles simulated I-V prediction, and measured maximum output power varies by only 1.34%.

  5. New method for measuring low NO concentrations using laser induced two photon ionization

    Science.gov (United States)

    Lee, Shan-Hu; Hirokawa, Jun; Kajii, Yoshizumi; Akimoto, Hajime

    1997-07-01

    A new method based on laser induced two photon ionization was developed for detection of low levels of NO concentration in the troposphere. A frequency-doubled pulsed dye laser operating at near 226 nm was used to photoionize NO by a (1+1) resonance enhanced two photon ionization via its A 2Σ←X2Π(0,0) band. NO ions are detected by an electron multiplier. Air gas samples are injected through a pulsed nozzle into a vacuum chamber. Cooling of rovibrational levels during the expansion process allows better selectivity for NO detection from other nitrocompounds. Measurement conditions were optimized as a function of X/D for the nozzle (X is the distance from the nozzle orifice to the ionization area, and D is the diameter of the nozzle orifice), laser power, and electron multiplier voltage. For the first time, selectivities for NO measurement, which were obtained from ion intensity ratios of NO and other nitrocompounds such as NO2 at the same concentrations, are discussed. A selectivity of 45 for NO vs NO2 was obtained using a 44 μJ pulse energy and an X/D of 120 for the nozzle. The current detection limit determined for NO was 16 pptv with an integration time of 1 min and a pulse energy of 44 μJ.

  6. A method for assessing residual NAPL based on organic chemical concentrations in soil samples

    International Nuclear Information System (INIS)

    Feenstra, S.; Mackay, D.M.; Cherry, J.A.

    1991-01-01

    Ground water contamination by non-aqueous phase liquid (NAPL) chemicals is a serious concern at many industrial facilities and waste disposal sites. NAPL in the form of immobile residual contamination, or pools of mobile or potentially mobile NAPL, can represent continuing sources of ground water contamination. In order to develop rational and cost-effective plans for remediation of soil and ground water contamination at such sites, it is essential to determine if non-aqueous phase liquid (NAPL) chemicals are present in the subsurface and delineate the zones of NAPL contamination. Qualitatively, soil analyses that exhibit chemical concentrations in the percent range or >10,000 mg/kg would generally be considered to indicate the presence of NAPL. However, the results of soil analyses are seldom used in a quantitative manner to assess the possible presence of residual NAPL contamination when chemical concentrations are lower and the presence of NAPL is not obvious. The assessment of the presence of NAPL in soil samples is possible using the results of chemical and physical analyses of the soil, and the fundamental principles of chemical partitioning in unsaturated or saturated soil. The method requires information on the soil of the type typically considered in ground water contamination studies and provides a simple tool for the investigators of chemical spill and waste disposal sites to assess whether soil chemical analyses indicate the presence of residual NAPL in the subsurface

  7. Research on the detection system of liquid concentration base on birefringence light transmission method

    Science.gov (United States)

    Li, Tianze; Zhang, Xia; Hou, Luan; Jiang, Chuan

    2010-10-01

    The characteristics of the beam transmitting in the optical fiber and the liquid medium are analyzed in this paper. On this basis, a new type of semiconductor optical position sensitive detector is used for a receiving device, a light transmission method of birefringence is presented,and a set of opto-electrical detection system which is applied to detect liquid concentration is designed. The system is mainly composed of semiconductor lasers,optical systems, Psd signal conditioning circuit, Single-chip System, A/D conversion circuit and display circuit. Through theoretical analysis and experimental simulations, the accuracy of this system has been verified. Some main factors affecting the test results are analyzed detailedly in this paper. The experiments show that the temperature drift and the light intensity have a very small impact on this system. The system has some advantages, such as the simple structure, high sensitivity, good stability, fast response time, high degree of automation, and so on. It also can achieve the real-time detection of liquid concentration conveniently and accurately. The system can be widely applied in chemical, food, pharmacy and many other industries. It has broad prospects of application.

  8. Apparatus and method for concentrating and filtering particles suspended in a fluid

    Science.gov (United States)

    Fiechtner, Gregory J [Bethesda, MD; Cummings, Eric B [Livermore, CA; Singh, Anup K [Danville, CA

    2009-05-19

    Disclosed is a device for separating and concentrating particles suspended in a fluid stream by using dielectrophoresis (DEP) to trap and/or deflect those particles as they migrate through a fluid channel. The method uses fluid channels designed to constrain a liquid flowing through it to uniform electrokinetic flow velocities. This behavior is achieved by connecting deep and shallow sections of channels, with the channel depth varying abruptly along an interface. By careful design of abrupt changes in specific permeability at the interface, an abrupt and spatially uniform change in electrokinetic force can be selected. Because these abrupt interfaces also cause a sharp gradient in applied electric fields, a DEP force also can be established along the interface. Depending on the complex conductivity of the suspended particles and the immersion liquid, the DEP force can controllably complement or oppose the local electrokinetic force transporting the fluid through the channel allowing for manipulation of particles suspended in the transporting liquid.

  9. Isotopic methods of investigations of hydrodynamics in installations for hydrometallurgic processing of copper concentrates

    International Nuclear Information System (INIS)

    Stsheletski, M.; Urban'ski, T.S.

    1979-01-01

    Isotope methods have been presented of investigations of hydrodynamics of liquid and solid phases in pilot-scale installations for hydrometallurgic processing of copper concentrates: in the column installation for leaching; in the tubular reactor for copper reduction by hydrogen and in the installation for crystallization of magnesium sulphate under pressure conditions. The column leaching installation has been tested by pulse injection of two radioisotope indicators simultaneously. The copper concentrate was labelled by sorbed colloidal gold-198 and the liquid phase was labelled by solution of sodium chloride containing sodium-24. Measurements of the radiation intensities were registered by scintillation counters, working with a single-channel amplitude analyzer, integrators and counting rate monitors. According to the distribution of time of stay, by the moments method, number of powers of ideal intermixings in the cell model of flow of the both phases. In the tubular reactor process of copper reduction by hydrogen is going on in three phases: gas-liquid-solig phase. Hydrodynamic investigations in this instalation was done in the presence of air, water and copper powder. Water was labelled by sodium-24 and copper powder by copper-64. Changes of intensity of radiation were measured by scintillation counters, located along the installation and were registered by multichannel amplitude analyzer. Peckle number and longitudal dispersion factor were determined. In investigations of the solid phase hydrodynamics during crystallization of magnesium sulphate under elevated temperature and high pressure, as an indicator, isotope gold-198 has been used, by which crystalls of the solid phase were labelled, and isotope sodium-24 was added to a liquid. Simultaneousely were measured and registered by a single-channel analyzer intensity of radiation of both indicators. Mean time of stay and parameters of a mathematical model of the phases flow in this installation were

  10. Improvements in methods of analyzing dust concentrations, and influence of the storage processes on dust concentrations in polar snow and ice samples

    Directory of Open Access Journals (Sweden)

    Takayuki Miyake

    2014-07-01

    Full Text Available We sought to improve the analytical methods employed when operating a laser particle counter and to evaluate the influence of the storage processes on dust concentrations in polar snow and ice samples. We corrected the particle size ranges and threshold voltage using the new calibration curve, confirmed the analytical precision and dust concentrations of blank of wipers using in a clean room, and managed any variations in the laser sensor's sensitivity by measuring standard particles. The 15 ml glass screw bottles without packing (liner of cap of bottles yielded the lowest dust concentration of the blank among two types of bottles and nine types of packing for dust analysis. Storage of samples of the Dome Fuji ice core (Antarctica in a refrigerator for 1 year resulted in just a 4% decrease in dust concentration, which is within the analytical precision of the laser particle counter. Storage in a freezer resulted in an increase in dust concentrations and a decrease in the ratio of large particles more than 0.98 μm in particle diameter in the samples, suggesting a change in dust particle size during storage and an influence by the materials of the storage bottles. The addition of dispersants to the Antarctic snow samples is not clearly suitable when analyzing dust concentrations after sample storage by refrigeration or freezing.

  11. Water quality - Determination of tritium activity concentration - Liquid scintillation counting method (International Standard Publication ISO 9698:1989)

    International Nuclear Information System (INIS)

    Stefanik, J.

    1999-01-01

    This International Standard specifies a method for the determination of tritiated water ([ 3 H]H 2 O) activity concentration in water by liquid scintillation counting. The method is applicable to all types of water including seawater with tritium activity concentrations of up to 10 6 Bq/m 3 when using 20 ml counting vials. Below tritium activity concentrations of about 5 x 10 4 Bq/m 3[ 8], a prior enrichment step and/or the measurement of larger sample volumes can significantly improve the accuracy of the determination and lower the limit of detection. Tritium activity concentrations higher than 10 6 Bq/m 3 may be determined after appropriate dilution with distilled water of proven low tritium content. An alternative method for the determination of these higher activities involves increasing the tritium activity concentrations of the internal standard solution. The method is not applicable to the analysis of organically bound tritium; its determination requires an oxidative digestion

  12. Feasibility of flotation concentration of fungal spores as a method to identify toxigenic mushrooms

    Directory of Open Access Journals (Sweden)

    Bazzle LJ

    2014-12-01

    Full Text Available Lisa J Bazzle,1 Marc A Cubeta,2 Steven L Marks,1 David C Dorman3 1Department of Clinical Sciences, College of Veterinary Medicine, 2Department of Plant Pathology, College of Agriculture and Life Sciences, Center for Integrated Fungal Research, 3Department of Molecular and Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA Purpose: Mushroom poisoning is a recurring and challenging problem in veterinary medicine. Diagnosis of mushroom exposure in animals is hampered by the lack of rapid diagnostic tests. Our study evaluated the feasibility of using flotation concentration and microscopic evaluation of spores for mushroom identification. Evaluation of this method in living animals exposed to toxigenic mushrooms is limited by ethical constraints; therefore, we relied upon the use of an in vitro model that mimics the oral and gastric phases of digestion. Methods: In our study, mycologist-identified toxigenic (poisonous and nontoxigenic fresh mushrooms were collected in North Carolina, USA. In phase 1, quantitative spore recovery rates were determined following magnesium sulfate, modified Sheather's sugar solution, and zinc sulfate flotation (n=16 fungal species. In phase 2, mushrooms (n=40 fungal species were macerated and digested for up to 2 hours in a salivary and gastric juice simulant. The partially digested material was acid neutralized, filtered, and spores concentrated using zinc sulfate flotation followed by microscopic evaluation of spore morphology. Results: Mean spore recovery rates for the three flotation fluids ranged from 32.5% to 41.0% (P=0.82. Mean (± standard error of the mean Amanita spp. spore recovery rates were 38.1%±3.4%, 36.9%±8.6%, and 74.5%±1.6% (P=0.0012 for the magnesium sulfate, Sheather's sugar, and zinc sulfate solutions, respectively. Zinc sulfate flotation following in vitro acid digestion (phase 2 yielded spore numbers adequate for microscopic visualization in

  13. Pink shrimp (P. brasiliensis and P. paulensis) residue: influence of extraction method on carotenoid concentration.

    Science.gov (United States)

    Mezzomo, Natália; Maestri, Bianca; dos Santos, Renata Lazzaris; Maraschin, Marcelo; Ferreira, Sandra R S

    2011-09-15

    The main residue from the shrimp processing is formed by head and carapace and represents from 40 to 50% (w/w) of the integral shrimp. The recovery of the carotenoid fraction from this residue stands for an alternative to increase its aggregated value. Therefore, the objective of this study was to use the pink shrimp waste as raw material to obtain carotenoid enriched extracts, evaluating different pre-treatments and extraction methods. The shrimp waste was supplied by a local public market (Florianópolis, SC, Brazil). The investigation of the different pre-treatments applied to the raw material shows that cooking associated with milling and drying produced the extract richest in carotenoid fraction. The extraction methods considered in this work were Soxhlet, maceration and ultrasound by means of different organic solvents and also a vegetable oil as solvent. The extracts were evaluated in terms of yield, carotenoid profile, total carotenoid content (TCC), UV-Visible scanning spectrophotometry and mid-Fourier transform infrared spectroscopy (FTIR). The results indicate that shrimp waste can provide carotenoid enriched extracts, particularly astaxanthin, in concentrations up to 252 μg(astaxanthin)g(extract)(-1). The most adequate solvents were acetone and hexane: isopropanol (50:50, v/v) used in the maceration procedure. The UV-Vis results revealed the presence of carotenoids and flavonoids in the extracts while the FTIR spectroscopy indicated the existence of fatty acids, proteins, and phenolics. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. A new one-platform flow cytometric method for residual cell counting in platelet concentrates.

    Science.gov (United States)

    Schmidt, Michael; Spengler, Hans-Peter; Lambrecht, Bernd; Hourfar, Michael K; Seifried, Erhard; Tonn, Torsten

    2009-12-01

    According to German regulations and guidelines, residual red blood cells (rRBCs) and residual white blood cells (rWBCs) must number fewer than 3 x 10(9) cells/unit and 1 x 10(6) cells/unit in platelet concentrates (PCs), respectively. Due to low levels of residual cells in final products, there is still a need for fast, reliable, and sensitive methods of automated detection of these cell types. In Part A, 21 PCs were spiked with predetermined numbers of red blood cells (RBCs) and white blood cells (WBCs). The linearity, precision, and accuracy of the BD Thrombo Count assay (BD Biosciences Europe) were tested and validated according to international guidelines. Finally in Part B, 100 PCs prepared from pooled buffy coats were tested by the BD Thrombo Count assay and compared with other methods, including Nageotte (rWBCs) and Neubauer (rRBCs) counting chambers and the flow cytometric BD LeucoCOUNT (Becton Dickinson) assay (rWBCs). The unspecific background of blank PC samples was fewer than 0.02 cells/microL for WBCs and fewer than 34 cells/microL for RBCs (mean, 21). Linear regression and precision analyses of spiked PC samples were determined for both WBCs (r(2) = 0.992; range, 0.6-6.0 WBCs/microL) and RBCs (r(2) = 0.999; 800-8000 RBCs/microL). No carryover of cells or drift in results was detected in the automated sample acquisition mode. Analysis according to statistical methods of Bland and Altman demonstrated a high correlation between BD Thrombo Count and the Neubauer manual counting chamber. This novel flow cytometric test is a quick and reliable single-tube assay that has been demonstrated as a potential alternative for the existing manual microscopic counting procedures that are both time-consuming and laborious.

  15. Assessment of colour changes during storage of elderberry juice concentrate solutions using the optimization method.

    Science.gov (United States)

    Walkowiak-Tomczak, Dorota; Czapski, Janusz; Młynarczyk, Karolina

    2016-01-01

    Elderberries are a source of dietary supplements and bioactive compounds, such as anthocyanins. These dyes are used in food technology. The aim of the study was to assess the changes in colour parameters, anthocyanin contents and sensory attributes in solutions of elderberry juice concentrates during storage in a model system and to determine predictability of sensory attributes of colour in solutions based on regression equations using the response surface methodology. The experiment was carried out according to the 3-level factorial design for three factors. Independent variables included pH, storage time and temperature. Dependent variables were assumed to be the components and colour parameters in the CIE L*a*b* system, pigment contents and sensory attributes. Changes in colour components X, Y, Z and colour parameters L*, a*, b*, C* and h* were most dependent on pH values. Colour lightness L* and tone h* increased with an increase in experimental factors, while the share of the red colour a* and colour saturation C* decreased. The greatest effect on the anthocyanin concentration was recorded for storage time. Sensory attributes deteriorated during storage. The highest correlation coefficients were found between the value of colour tone h* and anthocyanin contents in relation to the assessment of the naturalness and desirability of colour. A high goodness-of-fit of the model to data and high values of R2 for regression equations were obtained for all responses. The response surface method facilitates optimization of experimental factor values in order to obtain a specific attribute of the product, but not in all cases of the experiment. Within the tested range of factors, it is possible to predict changes in anthocyanin content and the sensory attributes of elderberry juice concentrate solutions as food dye, on the basis of the lack of a fit test. The highest stability of dyes and colour of elderberry solutions was found in the samples at pH 3.0, which confirms

  16. A titration method for determining individual oxidant concentration in the dual sodium persulfate and hydrogen peroxide oxidation system.

    Science.gov (United States)

    Liang, Chenju; He, Boyu

    2018-05-01

    The use of a dual oxidation system, which combines sodium persulfate (Na 2 S 2 O 8 , SPS) and hydrogen peroxide (H 2 O 2 , HP) is increasing as an in-situ chemical oxidation (ISCO) process for soil and groundwater remediation. An analytical method was assessed in this study for determining individual oxidant concentration in order to understand the interactions, and variations in the concentrations, of SPS and HP in aqueous systems containing both SPS and HP. The iodometric titration method was demonstrated to be capable of measuring total oxidant (SPS + HP) concentration; while the ceric sulfate titration method can be used specifically for measuring HP in the dual oxidation system without interfering with the iodometric titration. Therefore, SPS concentration can be deduced by subtraction of the HP concentration from the total oxidant concentration. Direct iodometric titration for determination of total oxidant at concentration above 20 mM exhibited <8% concentration. Based on the results of indirect determination of SPS in the dual oxidation system, an approximate 10% concentration variation was expected. This research may serve as a reference for measuring oxidant variations in this ISCO dual oxidant application. Copyright © 2018. Published by Elsevier Ltd.

  17. Method for sustaining microorganism culture in syngas fermentation process in decreased concentration or absence of various substrates

    Science.gov (United States)

    Adams, Stephen S.; Scott, Syrona; Ko, Ching-Whan

    2015-05-19

    The present invention relates to methods for sustaining microorganism culture in a syngas fermentation reactor in decreased concentration or absence of various substrates comprising: adding carbon dioxide and optionally alcohol; maintaining free acetic acid concentrations; and performing the above mentioned steps within specified time.

  18. A Method to Determine the Ball Filling, in Miduk Copper Concentrator SAG Mill

    Directory of Open Access Journals (Sweden)

    Ali Kamali Moaveni

    2012-12-01

    Full Text Available The aim of this research work was to investigate on the ball filling estimation of Miduk semi-autogenous (SAG Mill via an utilized method. Miduk copper concentrator is located in Kerman Province, Iran, and its size reduction stage includes one gyratory crusher which feeds one SAG mill (9.75 dia.(m*3.88 length(m following two parallel ball mills (5dia.(m*7lenght(m. After SAG mill, a trommel screen produces two over and under size materials which the oversize part is circulated into SAG mill and undersize reports to hydrocyclone for further process. Ball filling identify was implemented in this work using mill`s load sampling and ball abrasion test.These methods could estimate ball filling variation with easy, undeniable, and useful tests. Also, these tests have shown the digression of operating ball filling amount and its manual designed. To make more homogenous load, mill load samplings were carried out from 6 points after whirling the mill via inching motor. Acquired load sampling results were compared with ball abrasion tests. Ball abrasion tests were calculated for 3 different conditions include maximum, average, and minimum ball abrasion. However, the calculated maximum and minimum conditions never occurred. However, these are just for obtaining to ball filling variation in the mill. The results obtained from this work show, the ball filling percentage variation is between 1.2– 3.7% which is lower than mill ball filling percentage, according to the designed conditions (15%. In addition, acquired load samplings result for mill ball filling was 1.3%.

  19. The CAIRN method: automated, reproducible calculation of catchment-averaged denudation rates from cosmogenic nuclide concentrations

    Science.gov (United States)

    Marius Mudd, Simon; Harel, Marie-Alice; Hurst, Martin D.; Grieve, Stuart W. D.; Marrero, Shasta M.

    2016-08-01

    We report a new program for calculating catchment-averaged denudation rates from cosmogenic nuclide concentrations. The method (Catchment-Averaged denudatIon Rates from cosmogenic Nuclides: CAIRN) bundles previously reported production scaling and topographic shielding algorithms. In addition, it calculates production and shielding on a pixel-by-pixel basis. We explore the effect of sampling frequency across both azimuth (Δθ) and altitude (Δϕ) angles for topographic shielding and show that in high relief terrain a relatively high sampling frequency is required, with a good balance achieved between accuracy and computational expense at Δθ = 8° and Δϕ = 5°. CAIRN includes both internal and external uncertainty analysis, and is packaged in freely available software in order to facilitate easily reproducible denudation rate estimates. CAIRN calculates denudation rates but also automates catchment averaging of shielding and production, and thus can be used to provide reproducible input parameters for the CRONUS family of online calculators.

  20. Methods for Analyzing the Economic Value of Concentrating Solar Power with Thermal Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Denholm, Paul [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jorgenson, Jennie [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Miller, Mackay [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhou, Ella [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wang, Caixia [State Grid Energy Research Inst., Beijing (China)

    2015-07-20

    Concentrating solar power with thermal energy storage (CSP-TES) provides multiple quantifiable benefits compared to CSP without storage or to solar photovoltaic (PV) technology, including higher energy value, ancillary services value, and capacity value. This report describes modeling approaches to quantifying these benefits that have emerged through state-level policymaking in the United States as well as the potential applicability of these methods in China. The technical potential for CSP-TES in China is significant, but deployment has not yet achieved the targets established by the Chinese government. According to the 12th Five Year Plan for Renewable Energy (2011-2015), CSP was expected to reach 1 GW by 2015 and 3 GW by 2020 in China, yet as of December 2014, deployment totaled only 13.8 MW. One barrier to more rapid deployment is the lack of an incentive specific to CSP, such as a feed-in tariff. The 13th Five Year Plan for Solar Generation (2016-2020), which is under development, presents an opportunity to establish a feed-in tariff specific to CSP. This report, produced under the auspices of the U.S.-China Renewable Energy Partnership, aims to support the development of Chinese incentives that advance CSP deployment goals.

  1. CEMS Investigations of Fe-Silicide Phases Formed by the Method of Concentration Controlled Phase Selection

    International Nuclear Information System (INIS)

    Moodley, M. K.; Bharuth-Ram, K.; Waal, H. de; Pretorius, R.

    2002-01-01

    Conversion electron Moessbauer spectroscopy (CEMS) measurements have been made on Fe-silicide samples formed using the method of concentration controlled phase selection. To prepare the samples a 10 nm layer of Fe 30 M 70 (M=Cr, Ni) was evaporated onto Si(100) surfaces, followed by evaporation of a 60 nm Fe layer. Diffusion of the Fe into the Si substrate and the formation of different Fe-Si phases was achieved by subjecting the evaporated samples to a series of heating stages, which consisted of (a) a 10 min anneal at 800 deg. C plus etch of the residual surface layer, (b) a further 3 hr anneal at 800 deg. C, (c) a 60 mJ excimer laser anneal to an energy density of 0.8 J/cm 2 , and (d) a final 3 hr anneal at 800 deg. C. CEMS measurements were used to track the Fe-silicide phases formed. The CEMS spectra consisted of doublets which, based on established hyperfine parameters, could be assigned to α- or β-FeSi 2 or cubic FeSi. The spectra showed that β-FeSi 2 had formed already at the first annealing stage. Excimer laser annealing resulted in the formation of a phase with hyperfine parameters consistent with those of α-FeSi 2 . A further 3 hr anneal at 800 deg. C resulted in complete reversal to the semiconducting β-FeSi 2 phase.

  2. Studies on the method for determination of fluoride concentration in rat hard tissues by neutron activation analysis using 20F

    International Nuclear Information System (INIS)

    Nakakura, Tadao

    1991-01-01

    Neutron activation analysis method (non disruptive analysis, short time period measurement) has been recognized as a high precision analysis of fluoride concentration in hard tissue. Heat neutron irradiation analysis using instrumental neutron activation analysis (INAA) method was used to investigate 20 F concentration. Results were as follows. F concentration in a dried material of hard tissue using INAA method can be fixed by measuring the 20 F's energy peak for 10 seconds after neutron irradiation under 1 x 10 n/cm 2 ·s for 10 seconds. Non responding time that is caused by short half reduction time of 20 F can be recovered enough by a revise calculation. Reproducibility of measured fluoride concentration using INAA method was well stabilized. Rat hard tissue which takes no fluoride can be determined fluoride concentration without sodium restriction. Femur fluoride concentrations using INAA method had significant correlation with conventional microdiffusion analysis method (r=0.997, regression line: Y=1.13X + 2.98). Increase of fluoride density in dentine of rat molars under growing period according to fluoride intake was 1/3 of femurs and mandibles. (author)

  3. A new method to measure effective soil solution concentration predicts copper availability to plants.

    Science.gov (United States)

    Zhang, H; Zhao, F J; Sun, B; Davison, W; McGrath, S P

    2001-06-15

    Risk assessments of metal contaminated soils need to address metal bioavailability. To predict the bioavailability of metals to plants, it is necessary to understand both solution and solid phase supply processes in soils. In striving to find surrogate chemical measurements, scientists have focused either on soil solution chemistry, including free ion activities, or operationally defined fractions of metals. Here we introduce the new concept of effective concentration, CE, which includes both the soil solution concentration and an additional term, expressed as a concentration, that represents metal supplied from the solid phase. CE was measured using the technique of diffusive gradients in thin films (DGT) which, like a plant, locally lowers soil solution concentrations, inducing metal supply from the solid phase, as shown by a dynamic model of the DGT-soil system. Measurements of Cu as CE, soil solution concentration, by EDTA extraction and as free Cu2+ activity in soil solution were made on 29 different soils covering a large range of copper concentrations. Theywere compared to Cu concentrations in the plant material of Lepidium heterophyllum grown on the same soils. Plant concentrations were linearly related and highly correlated with CE but were more scattered and nonlinear with respect to free Cu2+ activity, EDTA extraction, or soil solution concentrations. These results demonstrate that the dominant supply processes in these soils are diffusion and labile metal release, which the DGT-soil system mimics. The quantity CE is shown to have promise as a quantitative measure of the bioavailable metal in soils.

  4. Simplified method for preparation of concentrated exoproteins produced by Staphylococcus aureus grown on surface of cellophane bag containing liquid medium.

    Science.gov (United States)

    Ikigai, H; Seki, K; Nishihara, S; Masuda, S

    1988-01-01

    A simplified method for preparation of concentrated exoproteins including protein A and alpha-toxin produced by Staphylococcus aureus was successfully devised. The concentrated proteins were obtained by cultivating S. aureus organisms on the surface of a liquid medium-containing cellophane bag enclosed in a sterilized glass flask. With the same amount of medium, the total amount of proteins obtained by the method presented here was identical with that obtained by conventional liquid culture. The concentration of proteins obtained by the method, however, was high enough to observe their distinct bands stained on polyacrylamide gel electrophoresis. This method was considered quite useful not only for large-scale cultivation for the purification of staphylococcal proteins but also for small-scale study using the proteins. The precise description of the method was presented and its possible usefulness was discussed.

  5. A method for the measurement of in line pistachio aflatoxin concentration based on the laser induced fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Paghaleh, Soodeh Jamali [Vali-e-Asr University of Rafsanjan, Rafsanjan (Iran, Islamic Republic of); Askari, Hassan Ranjbar; Marashi, Seyed Mohammad Bagher [Department of Physics, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan (Iran, Islamic Republic of); Rahimi, Mojtaba, E-mail: m_rahimi@vru.ac.ir [Department of Physics, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan (Iran, Islamic Republic of); Bahrampour, Ali Reza [Physics Department of Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2015-05-15

    Contamination of pistachio nuts with aflatoxin is one of the most significant issues related to pistachio health and expert. A fast pistachio aflatoxin concentration measurement method based on the laser induced fluorescence spectroscopy (LIFS) is proposed. The proposed method from theoretical and experimental points of view is analyzed. In our experiments XeCl Excimer laser is employed as an Ultra Violet (UV) source (λ=308 nm) and a UV–visible (UV–vis) spectrometer is used for fluorescent emission detection. Our setup is employed to measure the concentration of different type of Aflatoxins in pistachio nuts. Measurements results obtained by the LIFS method are compared with those are measured by the standard HPLC method. Aflatoxins concentrations are in good agreement with those are obtained by the HPLC method. The proposed laser induced fluorescence spectroscopy can be used as an in line aflatoxins concentrations measurement instrument for industrial applications. - Highlights: • XeCl Excimer laser is employed as an UV source for measurement of AFs in pistachio nuts. • Results are compared with those are measured by the standard HPLC method. • LIFS is an online AFs concentration measurement method for industrial applications.

  6. A method for the measurement of in line pistachio aflatoxin concentration based on the laser induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Paghaleh, Soodeh Jamali; Askari, Hassan Ranjbar; Marashi, Seyed Mohammad Bagher; Rahimi, Mojtaba; Bahrampour, Ali Reza

    2015-01-01

    Contamination of pistachio nuts with aflatoxin is one of the most significant issues related to pistachio health and expert. A fast pistachio aflatoxin concentration measurement method based on the laser induced fluorescence spectroscopy (LIFS) is proposed. The proposed method from theoretical and experimental points of view is analyzed. In our experiments XeCl Excimer laser is employed as an Ultra Violet (UV) source (λ=308 nm) and a UV–visible (UV–vis) spectrometer is used for fluorescent emission detection. Our setup is employed to measure the concentration of different type of Aflatoxins in pistachio nuts. Measurements results obtained by the LIFS method are compared with those are measured by the standard HPLC method. Aflatoxins concentrations are in good agreement with those are obtained by the HPLC method. The proposed laser induced fluorescence spectroscopy can be used as an in line aflatoxins concentrations measurement instrument for industrial applications. - Highlights: • XeCl Excimer laser is employed as an UV source for measurement of AFs in pistachio nuts. • Results are compared with those are measured by the standard HPLC method. • LIFS is an online AFs concentration measurement method for industrial applications

  7. Evaluation of methods for the concentration and extraction of viruses from sewage in the context of metagenomic sequencing

    DEFF Research Database (Denmark)

    Hjelmsø, Mathis Hjort; Hellmér, Maria; Fernandez-Cassi, Xavier

    2017-01-01

    concentrations. This necessitates a step of sample concentration to allow for sensitive virus detection. Additionally, viruses harbor a large diversity of both surface and genome structures, which makes universal viral genomic extraction difficult. Current studies have tackled these challenges in many different...... this study aimed to evaluate the efficiency of four commonly applied viral concentrations techniques (precipitation with polyethylene glycol, organic flocculation with skim milk, monolithic adsorption filtration and glass wool filtration) and extraction methods (Nucleospin RNA XS, QIAamp Viral RNA Mini Kit...... or PowerViral® Environmental RNA/DNA Isolation Kit. Highest viral specificity were found in samples concentrated by precipitation with polyethylene glycol or extracted with Nucleospin RNA XS. Detection of viral pathogens depended on the method used. These results contribute to the understanding of method...

  8. Effects of Heterogeneities, Sampling Frequencies, Tools and Methods on Uncertainties in Subsurface Contaminant Concentration Measurements

    Science.gov (United States)

    Ezzedine, S. M.; McNab, W. W.

    2007-12-01

    uncertainties in the concentration measurements. Finally, the models and results were abstracted using a simple mixed-tank approach to further simplify the models and make them more accessible to field hydrogeologists. During the abstraction process a novel method was developed for mapping streamlines in the fractures as well within the monitoring well to illustrate mixing and mixing zones. Applications will be demonstrated for both sampling in porous and fractured media. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

  9. White blood cell fragments in platelet concentrates prepared by the platelet-rich plasma or buffy-coat methods

    NARCIS (Netherlands)

    Dijkstra-Tiekstra, M. J.; van der Schoot, C. E.; Pietersz, R. N. I.; Reesink, H. W.

    2005-01-01

    BACKGROUND AND OBJECTIVES: White blood cell (WBC) fragments in platelet concentrates (PCs) may induce allo-immunization in the recipient. MATERIALS AND METHODS: As the level of WBC fragments can differ between PCs produced using different methods, we compared PCs prepared by using the buffy-coat

  10. Methods for estimating on-site ambient air concentrations at disposal sites

    International Nuclear Information System (INIS)

    Hwang, S.T.

    1987-01-01

    Currently, Gaussian type dispersion modeling and point source approximation are combined to estimate the ambient air concentrations of pollutants dispersed downwind of an areawide emission source, using the approach of virtual point source approximation. This Gaussian dispersion modeling becomes less accurate as the receptor comes closer to the source, and becomes inapplicable for the estimation of on-site ambient air concentrations at disposal sites. Partial differential equations are solved with appropriate boundary conditions for use in estimating the on-site concentrations in the ambient air impacted by emissions from an area source such as land disposal sites. Two variations of solution techniques are presented, and their predictions are compared

  11. A rapid method of predicting radiocaesium concentrations in sheep from activity levels in faeces

    International Nuclear Information System (INIS)

    McGee, E.J.; Synnott, H.J.; Colgan, P.A.; Keatinge, M.J.

    1994-01-01

    The use of faecal samples taken from sheep flocks as a means of predicting radiocaesium concentrations in live animals was studied. Radiocaesium levels in 1726 sheep from 29 flocks were measured using in vivo techniques and a single faecal sample taken from each flock was also analysed. A highly significant relationship was found to exist between mean flock activity and activity in the corresponding faecal samples. Least-square regression yielded a simple model for predicting mean flock radiocaesium concentrations based on activity levels in faecal samples. A similar analysis of flock maxima and activity levels in faeces provides an alternative model for predicting the expected within-flock maximum radiocaesium concentration. (Author)

  12. Digitized Onondaga Lake Dissolved Oxygen Concentrations and Model Simulated Values using Bayesian Monte Carlo Methods

    Data.gov (United States)

    U.S. Environmental Protection Agency — The dataset is lake dissolved oxygen concentrations obtained form plots published by Gelda et al. (1996) and lake reaeration model simulated values using Bayesian...

  13. Using fractional extraction method to separate Mo from U in high concentration solution

    International Nuclear Information System (INIS)

    Zhao Pinzhi; Cheng Guangrong; Ma Xiuhua

    1996-01-01

    The author presents investigation on separating Mo from U in acid high concentration lixivium with fractional extraction of secondary amine (7203) and D2EHPA and preparing qualified products of ammonium molybdate and sodium diuranate

  14. [Improvement of sensitivity in the second generation HCV core antigen assay by a novel concentration method using polyethylene glycol (PEG)].

    Science.gov (United States)

    Higashimoto, Makiko; Takahashi, Masahiko; Jokyu, Ritsuko; Syundou, Hiromi; Saito, Hidetsugu

    2007-11-01

    A HCV core antigen (Ag) detection assay system, Lumipulse Ortho HCV Ag has been developed and is commercially available in Japan with a lower detection level limit of 50 fmol/l, which is equivalent to 20 KIU/ml in PCR quantitative assay. HCV core Ag assay has an advantage of broader dynamic range compared with PCR assay, however the sensitivity is lower than PCR. We developed a novel HCV core Ag concentration method using polyethylene glycol (PEG), which can improve the sensitivity five times better than the original assay. The reproducibility was examined by consecutive five-time measurement of HCV patients serum, in which the results of HCV core Ag original and concentrated method were 56.8 +/- 8.1 fmol/l (mean +/- SD), CV 14.2% and 322.9 +/- 45.5 fmol/l CV 14.0%, respectively. The assay results of HCV negative samples in original HCV core Ag were all 0.1 fmol/l and the results were same even in the concentration method. The results of concentration method were 5.7 times higher than original assay, which was almost equal to theoretical rate as expected. The assay results of serially diluted samples were also as same as expected data in both original and concentration assay. We confirmed that the sensitivity of HCV core Ag concentration method had almost as same sensitivity as PCR high range assay in the competitive assay study using the serially monitored samples of five HCV patients during interferon therapy. A novel concentration method using PEG in HCV core Ag assay system seems to be useful for assessing and monitoring interferon treatment for HCV.

  15. Application of a PEG precipitation method for solubility screening: A tool for developing high protein concentration formulations

    Science.gov (United States)

    Li, Li; Kantor, Angela; Warne, Nicholas

    2013-01-01

    Previous publications demonstrated that the extrapolated solubility by polyethylene glycol (PEG) precipitation method (Middaugh et al., J Biol Chem 1979; 254:367–370; Juckes, Biochim Biophys Acta 1971; 229:535–546; Foster et al., Biochim Biophys Acta 1973; 317:505; Mahadevan and Hall, AIChE J 1990; 36:1517–1528; Stevenson and Hageman, Pharm Res 1995; 12:1671–1676) has a strong correlation to experimentally measured solubility of proteins. Here, we explored the utility of extrapolated solubility as a method to compare multiple protein drug candidates when nonideality of a highly soluble protein prohibits accurate quantitative solubility prediction. To achieve high efficiency and reduce the amount of protein required, the method is miniaturized to microwell plate format for high-throughput screening application. In this simplified version of the method, comparative solubility of proteins can be obtained without the need of concentration measurement of the supernatant following the precipitation step in the conventional method. The monoclonal antibodies with the lowest apparent solubilities determined by this method are the most difficult to be concentrated, indicating a good correlation between the prediction and empirical observations. This study also shows that the PEG precipitation method gives results for opalescence prediction that favorably compares to experimentally determined opalescence levels at high concentration. This approach may be useful in detecting proteins with potential solubility and opalescence problems prior to the time-consuming and expensive development process of high concentration formulation. PMID:23740802

  16. Resazurin-based 96-well plate microdilution method for the determination of minimum inhibitory concentration of biosurfactants.

    Science.gov (United States)

    Elshikh, Mohamed; Ahmed, Syed; Funston, Scott; Dunlop, Paul; McGaw, Mark; Marchant, Roger; Banat, Ibrahim M

    2016-06-01

    To develop and validate a microdilution method for measuring the minimum inhibitory concentration (MIC) of biosurfactants. A standardized microdilution method including resazurin dye has been developed for measuring the MIC of biosurfactants and its validity was established through the replication of tetracycline and gentamicin MIC determination with standard bacterial strains. This new method allows the generation of accurate MIC measurements, whilst overcoming critical issues related to colour and solubility which may interfere with growth measurements for many types of biosurfactant extracts.

  17. Variation in colostral immunoglobulin G concentration in fat tailed sheep and evaluation of methods for estimation of colostral immunoglobulin content

    Directory of Open Access Journals (Sweden)

    Saeid Tabatabaei

    2013-01-01

    Full Text Available In ruminants, colostrum is a vital source of immunoglobulins that provide passive immunity for their offspring during the neonatal period. It is suggested that colostral immunoglobulin G (IgG concentration varies between and within breeds and could also be affected by maternal factors. The aim of this study was to investigate possible effects of litter type and ewe parturition number on colostral IgG concentration in two Iranian fat-tailed breeds of sheep (Shaul and Lori Bakhtyari as well as usefulness of different methods for estimation of IgG concentrations in colostrum. The colostral IgG concentrations were measured in 38 Shaul and 59 Lori Bakhtyari ewes by single radial immunodiffusion, zinc sulphate turbidity and Biuret methods. Measurement of IgG by single radial immunodiffusion revealed that Lori Bakhtyari ewes had significantly (P 0.05 lower colostral IgG levels (48.82 ± 2.10 mg/ml than Shaul ewes (62.86 ± 2.48. With regard to the effect of litter type and parturition number, a significant (P 0.05 difference in IgG concentration of colostrum was only observed between the first (65.17 ± 5.74 mg/ml and third parturition (41.10 ± 4.60 mg/ml of Lori Bakhtyari ewes. The colostral IgG concentration was not associated with ewe serum IgG concentration (P > 0.05. The mortality rate was higher in lambs born to ewes with lower IgG in their colostrum. Single radial immunodiffusion did not correlate either with zinc sulphate turbidity method (r = -0.253, P > 0.05 or with Biuret method (r = -0.005, P > 0.05. We can conclude that concentration of colostral IgG could be influenced by breed but not by litter type and parturition number.

  18. Combined use of Clauss and prothrombin time-derived methods for determining fibrinogen concentrations: Screening for congenital dysfibrinogenemia.

    Science.gov (United States)

    Xiang, Liqun; Luo, Meiling; Yan, Jie; Liao, Lin; Zhou, Weijie; Deng, Xuelian; Deng, Donghong; Cheng, Peng; Lin, Faquan

    2017-09-18

    In this study, the significance of fibrinogen concentration assessed by a combination of Clauss and prothrombin time (PT)-derived methods for screening for congenital dysfibrinogenemia were investigated, and the screening efficiency of fibrinogen PT-derived/Clauss ratio on congenital dysfibrinogenemia was analyzed. We compared fibrinogen concentrations determined by the Clauss, PT-derived, and enzyme-linked immunosorbent assay (ELISA) methods in 73 patients with congenital dysfibrinogenemia and 81 normal controls. Receiver operating characteristic (ROC) curves were utilized to evaluate the efficacy of fibrinogen PT-derived/Clauss ratio in screening for congenital dysfibrinogenemia. Fibrinogen concentrations determined by the Clauss method were dramatically lower than by the PT-derived method and ELISA, and correlated poorly with the latter two methods in patients with congenital dysfibrinogenemia. Fibrinogen concentrations in normal controls were slightly lower according to the Clauss method than to the PT-derived method and ELISA; however, each method yielded results within the normal range and the correlation was good. The area under the ROC curve of fibrinogen PT-derived/Clauss ratio for diagnosis of congenital dysfibrinogenemia was 1 with a standard error of 0, 95% confidence interval of 0.976-1.00, and optimal critical diagnosis point of 1.43. When fibrinogen PT-derived/Clauss ratio was >1.43, the sensitivity and specificity for diagnosis of congenital dysfibrinogenemia were both 100%. The combined use of Clauss and PT-derived methods for determining fibrinogen concentrations improves the efficiency of screening for congenital dysfibrinogenemia, as the fibrinogen PT-derived/Clauss ratio has high sensitivity and specificity in diagnosis of congenital dysfibrinogenemia. This ratio could serve an important screening tool for this disease. © 2017 Wiley Periodicals, Inc.

  19. Comparing concentration methods: parasitrap® versus Kato-Katz for studying the prevalence of Helminths in Bengo province, Angola.

    Science.gov (United States)

    Mirante, Clara; Clemente, Isabel; Zambu, Graciette; Alexandre, Catarina; Ganga, Teresa; Mayer, Carlos; Brito, Miguel

    2016-09-01

    Helminth intestinal parasitoses are responsible for high levels of child mortality and morbidity. Hence, the capacity to diagnose these parasitoses and consequently ensure due treatment represents a factor of great importance. The main objective of this study involves comparing two methods of concentration, parasitrap and Kato-Katz, for the diagnosis of intestinal parasitoses in faecal samples. Sample processing made recourse to two different concentration methods: the commercial parasitrap® method and the Kato-Katz method. We correspondingly collected a total of 610 stool samples from pre-school and school age children. The results demonstrate the incidence of helminth parasites in 32.8% or 32.3% of the sample collected depending on whether the concentration method applied was either the parasitrap method or the Kato-Katz method. We detected a relatively high percentage of samples testing positive for two or more species of helminth parasites. We would highlight that in searching for larvae the Kato-Katz method does not prove as appropriate as the parasitrap method. Both techniques prove easily applicable even in field working conditions and returning mutually agreeing results. This study concludes in favour of the need for deworming programs and greater public awareness among the rural populations of Angola.

  20. Geographical distribution of the annual mean radon concentrations in primary schools of Southern Serbia – application of geostatistical methods

    International Nuclear Information System (INIS)

    Bossew, P.; Žunić, Z.S.; Stojanovska, Z.; Tollefsen, T.; Carpentieri, C.; Veselinović, N.; Komatina, S.; Vaupotič, J.; Simović, R.D.; Antignani, S.; Bochicchio, F.

    2014-01-01

    Between 2008 and 2011 a survey of radon ( 222 Rn) was performed in schools of several districts of Southern Serbia. Some results have been published previously (Žunić et al., 2010; Carpentieri et al., 2011; Žunić et al., 2013). This article concentrates on the geographical distribution of the measured Rn concentrations. Applying geostatistical methods we generate “school radon maps” of expected concentrations and of estimated probabilities that a concentration threshold is exceeded. The resulting maps show a clearly structured spatial pattern which appears related to the geological background. In particular in areas with vulcanite and granitoid rocks, elevated radon (Rn) concentrations can be expected. The “school radon map” can therefore be considered as proxy to a map of the geogenic radon potential, and allows identification of radon-prone areas, i.e. areas in which higher Rn radon concentrations can be expected for natural reasons. It must be stressed that the “radon hazard”, or potential risk, estimated this way, has to be distinguished from the actual radon risk, which is a function of exposure. This in turn may require (depending on the target variable which is supposed to measure risk) considering demographic and sociological reality, i.e. population density, distribution of building styles and living habits. -- Highlights: • A map of Rn concentrations in primary schools of Southern Serbia. • Application of geostatistical methods. • Correlation with geology found. • Can serve as proxy to identify radon prone areas

  1. COMPARISON OF DIFFERENT EXTRACTION METHODS REPRESENTING AVAILABLE AND TOTAL CONCENTRATIONS OF Cd, Cu, Fe, Mn and Zn IN SOIL

    Directory of Open Access Journals (Sweden)

    Vladimir Ivezić

    2013-06-01

    Full Text Available Various extraction methods are used to predict plant uptake of trace metals. Most commonly it is total concentration that is used for risk assessment and evaluation of trace metal availability. However, recent studies showed that total concentration is a poor indicator of availability while concentrations in soil solution show good correlation with plant uptake. Present study was conducted on magricultural soils with low levels of trace metals where 45 soil samples were collected from different soil types. The main objective was to compare four different extraction methods and examine how total and reactive (EDTA trace metal concentrations correlate ,with soil solution concentration (in this study determined by water extraction. The samples were analyzed by four extraction methods: strong acid extraction (ultra-pure HNO3 extraction and aqua regia, weak acid extraction by EDTA and the most available fraction, fraction in soil solution, were represented by water extraction (weakest extractant. Five elements were investigated (Cd, Cu, Fe, Mn and Zn. Water extraction significantly correlated with EDTA extraction for Cu, Fe and Mn, while total extraction (HNO3 extraction and aqua regia correlated significantly with water extraction only for Cu. No correlation between water extraction and total extraction confirmed poor role of total concentration as an indicator of availability. EDTA extraction can be used to represent reactive pool of trace metals in soil but it should be also taken with caution when using it to describe available fraction.

  2. Measurement of trimethylamine concentration and evaluation of pig meat natural quality by a spectrophotometric method

    Directory of Open Access Journals (Sweden)

    Mohammod Abdul HAMID,Xi WANG,Xiangdong DING,Chuduan WANG,Xingbo ZHAO

    2014-09-01

    Full Text Available Pig meat off-flavor is attributed to trimethylamine (TMA concentration, and it is considered as the precursor of the fishy off-flavor problems. In this study, TMA concentrations in pig meat were determined, and the interactions with breed and gender effects were discussed. In addition, the TMA threshold for meat off-flavor and pig meat natural quality was measured in relation to meat storage and movement, and the influential factors including the pig breed and storage time were discussed. The results indicated positive effects on the precursor of the fishy off-flavor and the TMA threshold. Native breeds were found to have lower TMA concentrations than European breeds (P<0.01, and females and castrated males had significantly lower TMA concentration than males (P<0.01, The threshold concentration of TMA when meat was classed as off-flavored was 25 μg·g-1, and this occurred after 35–38 h of storage. The natural qualities, such as appearance, flavor, color and overall acceptable scores declined significantly after 4 days in storage (P<0.01. It is concluded that pig meat off-flavor, breed and gender were essential factors affecting flavor for meat breeding programs, and storage time is important for pig meat natural quality.

  3. Evaluation of two methods to measure hemoglobin concentration among women with genetic hemoglobin disorders in Cambodia: a method-comparison study.

    Science.gov (United States)

    Karakochuk, Crystal D; Janmohamed, Amynah; Whitfield, Kyly C; Barr, Susan I; Vercauteren, Suzanne M; Kroeun, Hou; Talukder, Aminuzzaman; McLean, Judy; Green, Timothy J

    2015-02-20

    Genetic hemoglobin (Hb) E variants are common in Cambodia and result in an altered and unstable Hb molecule. We evaluated two methods to measure Hb concentration among individuals with and without Hb variants using a hemoglobinometer (HemoCue) and a hematology analyzer (Sysmex XT-1800i). We determined the bias and concordance between the methods among 420 Cambodian women (18-45 y). Bias and concordance appeared similar between methods among women with no Hb disorders (n=195, bias=2.5, ρc=0.68), women with Hb E variants (n=133, bias=2.5, ρc=0.78), and women with other Hb variants (n=92, bias=2.7, ρc=0.73). The overall bias was 2.6g/l, resulting in a difference in anemia prevalence of 11.5% (41% using HemoCue and 29.5% using Sysmex, p<0.001). Based on visual interpretation of the concordance plots, the HemoCue device appears to underestimate Hb concentrations at lower Hb concentrations and to overestimate Hb concentrations at higher Hb concentrations (in comparison to the Sysmex analyzer). Bias and concordance were similar across groups, suggesting the two methods of Hb measurement were comparable. We caution field staff, researchers and policy makers in the interpretation of data and the impact that bias between methods can have on anemia prevalence rates. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Comparison of interpolation methods for sparse data: Application to wind and concentration fields

    International Nuclear Information System (INIS)

    Goodin, W.R.; McRae, G.J.; Seinfield, J.H.

    1979-01-01

    in order to produce gridded fields of pollutant concentration data and surface wind data for use in an air quality model, a number of techniques for interpolating sparse data values are compared. The techniques are compared using three data sets. One is an idealized concentration distribution to which the exact solution is known, the second is a potential flow field, while the third consists of surface ozone concentrations measured in the Los Angeles Basin on a particular day. The results of the study indicate that fitting a second-degree polynomial to each subregion (triangle) in the plane with each data point weighted according to its distance form the subregion provides a good compromise between accuracy and computational cost

  5. Comparison of methods for evaluation of wood smoke and estimation of UK ambient concentrations

    Directory of Open Access Journals (Sweden)

    R. M. Harrison

    2012-09-01

    Full Text Available Airborne concentrations of the wood smoke tracers, levoglucosan and fine potassium have been measured at urban and rural sites in the United Kingdom alongside measurements with a multi-wavelength aethalometer. The UK sites, and especially those in cities, show low ratios of levoglucosan to potassium in comparison to the majority of published data. It is concluded that there may be two distinct source types, one from wood stoves and fireplaces with a high organic carbon content, best represented by levoglucosan, the other from larger, modern appliances with a very high burn-out efficiency, best represented by potassium. Based upon levoglucosan concentrations and a conversion factor of 11.2 from levoglucosan to wood smoke mass, average concentrations of wood smoke including winter and summer sampling periods are 0.23 μg m−3 in Birmingham and 0.33 μg m−3 in London, well below concentrations typical of other northern European urban areas. There may be a further contribution from sources of potassium-rich emissions amounting to an estimated 0.08 μg m−3 in Birmingham and 0.30 μg m−3 in London. Concentrations were highly correlated between two London sites separated by 4 km suggesting that a regional source is responsible. Data from the aethalometer are either supportive of these conclusions or suggest higher concentrations, depending upon the way in which the data are analysed.

  6. A Two-Stage Method to Estimate the Contribution of Road Traffic to PM₂.₅ Concentrations in Beijing, China.

    Science.gov (United States)

    Fang, Xin; Li, Runkui; Xu, Qun; Bottai, Matteo; Fang, Fang; Cao, Yang

    2016-01-13

    Fine particulate matters with aerodynamic diameters smaller than 2.5 micrometers (PM2.5) have been a critical environmental problem in China due to the rapid road vehicle growth in recent years. To date, most methods available to estimate traffic contributions to ambient PM2.5 concentration are often hampered by the need for collecting data on traffic volume, vehicle type and emission profile. To develop a simplified and indirect method to estimate the contribution of traffic to PM2.5 concentration in Beijing, China. Hourly PM2.5 concentration data, daily meteorological data and geographic information were collected at 35 air quality monitoring (AQM) stations in Beijing between 2013 and 2014. Based on the PM2.5 concentrations of different AQM station types, a two-stage method comprising a dispersion model and generalized additive mixed model (GAMM) was developed to estimate separately the traffic and non-traffic contributions to daily PM2.5 concentration. The geographical trend of PM2.5 concentrations was investigated using generalized linear mixed model. The temporal trend of PM2.5 and non-linear relationship between PM2.5 and meteorological conditions were assessed using GAMM. The medians of daily PM2.5 concentrations during 2013-2014 at 35 AQM stations in Beijing ranged from 40 to 92 μg/m³. There was a significant increasing trend of PM2.5 concentration from north to south. The contributions of road traffic to daily PM2.5 concentrations ranged from 17.2% to 37.3% with an average 30%. The greatest contribution was found at AQM stations near busy roads. On average, the contribution of road traffic at urban stations was 14% higher than that at rural stations. Traffic emissions account for a substantial share of daily total PM2.5 concentrations in Beijing. Our two-stage method is a useful and convenient tool in ecological and epidemiological studies to estimate the traffic contribution to PM2.5 concentrations when there is limited information on vehicle number and

  7. DEVELOPMENT OF ANALYTICAL METHODS FOR DETERMINING SUPPRESSOR CONCENTRATION IN THE MCU NEXT GENERATION SOLVENT (NGS)

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, K.; Fondeur, F.; White, T.; Diprete, D.; Milliken, C.

    2013-07-31

    Savannah River National Laboratory (SRNL) was tasked with identifying and developing at least one, but preferably two methods for quantifying the suppressor in the Next Generation Solvent (NGS) system. The suppressor is a guanidine derivative, N,N',N"-tris(3,7-dimethyloctyl)guanidine (TiDG). A list of 10 possible methods was generated, and screening experiments were performed for 8 of the 10 methods. After completion of the screening experiments, the non-aqueous acid-base titration was determined to be the most promising, and was selected for further development as the primary method. {sup 1}H NMR also showed promising results from the screening experiments, and this method was selected for further development as the secondary method. Other methods, including {sup 36}Cl radiocounting and ion chromatography, also showed promise; however, due to the similarity to the primary method (titration) and the inability to differentiate between TiDG and TOA (tri-n-ocytlamine) in the blended solvent, {sup 1}H NMR was selected over these methods. Analysis of radioactive samples obtained from real waste ESS (extraction, scrub, strip) testing using the titration method showed good results. Based on these results, the titration method was selected as the method of choice for TiDG measurement. {sup 1}H NMR has been selected as the secondary (back-up) method, and additional work is planned to further develop this method and to verify the method using radioactive samples. Procedures for analyzing radioactive samples of both pure NGS and blended solvent were developed and issued for the both methods.

  8. Method to determine the activity concentration and total activity of radioactive waste

    International Nuclear Information System (INIS)

    Angeles C, A.

    2001-02-01

    A characteristic system of radioactive waste is described to determine the concentration of radionuclides activity and the total activity of bundles of radioactive waste. The system this integrated by three subsystems: - Elevator of drums. - Electromechanics. - Gamma spectroscopy. In the system it is analyzed waste of issuing gamma specifically, and this designed for materials of relative low density and it analyzes materials of cylindrical recipients

  9. Quantifying Protein Concentrations Using Smartphone Colorimetry: A New Method for an Established Test

    Science.gov (United States)

    Gee, Clifford T.; Kehoe, Eric; Pomerantz, William C. K.; Penn, R. Lee

    2017-01-01

    Proteins are involved in nearly every biological process, which makes them of interest to a range of scientists. Previous work has shown that hand-held cameras can be used to determine the concentration of colored analytes in solution, and this paper extends the approach to reactions involving a color change in order to quantify protein…

  10. analysis of flow in a concentric annulus using finite element method

    African Journals Online (AJOL)

    user

    Annular flow is a flow regime of two-phase gas-liquid. It is characterized by the presence of liquid fluid flowing on an annulus shaped channel. Annular flow is important in drilling and production in deviated and horizontal wells [2]. Concentric annular flows of fluids in pipes have had a number of engineering applications.

  11. The Research on Analytical Method of Diquat Dibromide in Diquat Technical Concentrates

    Directory of Open Access Journals (Sweden)

    Gu Bing

    2016-01-01

    Full Text Available The technical concentrates (TK is prepared by technical material (TC, the content is lower than TC, it can be used for the preparation of pesticide formulations. Diquat TK is generally brown or dark brown liquid. In recent years, it develops rapidly as herbicides. This paper mainly introduces the research on analyses of the effective components in diquat TK.

  12. Micro-Droplet Detection Method for Measuring the Concentration of Alkaline Phosphatase-Labeled Nanoparticles in Fluorescence Microscopy

    Directory of Open Access Journals (Sweden)

    Rufeng Li

    2017-11-01

    Full Text Available This paper developed and evaluated a quantitative image analysis method to measure the concentration of the nanoparticles on which alkaline phosphatase (AP was immobilized. These AP-labeled nanoparticles are widely used as signal markers for tagging biomolecules at nanometer and sub-nanometer scales. The AP-labeled nanoparticle concentration measurement can then be directly used to quantitatively analyze the biomolecular concentration. Micro-droplets are mono-dispersed micro-reactors that can be used to encapsulate and detect AP-labeled nanoparticles. Micro-droplets include both empty micro-droplets and fluorescent micro-droplets, while fluorescent micro-droplets are generated from the fluorescence reaction between the APs adhering to a single nanoparticle and corresponding fluorogenic substrates within droplets. By detecting micro-droplets and calculating the proportion of fluorescent micro-droplets to the overall micro-droplets, we can calculate the AP-labeled nanoparticle concentration. The proposed micro-droplet detection method includes the following steps: (1 Gaussian filtering to remove the noise of overall fluorescent targets, (2 a contrast-limited, adaptive histogram equalization processing to enhance the contrast of weakly luminescent micro-droplets, (3 an red maximizing inter-class variance thresholding method (OTSU to segment the enhanced image for getting the binary map of the overall micro-droplets, (4 a circular Hough transform (CHT method to detect overall micro-droplets and (5 an intensity-mean-based thresholding segmentation method to extract the fluorescent micro-droplets. The experimental results of fluorescent micro-droplet images show that the average accuracy of our micro-droplet detection method is 0.9586; the average true positive rate is 0.9502; and the average false positive rate is 0.0073. The detection method can be successfully applied to measure AP-labeled nanoparticle concentration in fluorescence microscopy.

  13. Micro-Droplet Detection Method for Measuring the Concentration of Alkaline Phosphatase-Labeled Nanoparticles in Fluorescence Microscopy.

    Science.gov (United States)

    Li, Rufeng; Wang, Yibei; Xu, Hong; Fei, Baowei; Qin, Binjie

    2017-11-21

    This paper developed and evaluated a quantitative image analysis method to measure the concentration of the nanoparticles on which alkaline phosphatase (AP) was immobilized. These AP-labeled nanoparticles are widely used as signal markers for tagging biomolecules at nanometer and sub-nanometer scales. The AP-labeled nanoparticle concentration measurement can then be directly used to quantitatively analyze the biomolecular concentration. Micro-droplets are mono-dispersed micro-reactors that can be used to encapsulate and detect AP-labeled nanoparticles. Micro-droplets include both empty micro-droplets and fluorescent micro-droplets, while fluorescent micro-droplets are generated from the fluorescence reaction between the APs adhering to a single nanoparticle and corresponding fluorogenic substrates within droplets. By detecting micro-droplets and calculating the proportion of fluorescent micro-droplets to the overall micro-droplets, we can calculate the AP-labeled nanoparticle concentration. The proposed micro-droplet detection method includes the following steps: (1) Gaussian filtering to remove the noise of overall fluorescent targets, (2) a contrast-limited, adaptive histogram equalization processing to enhance the contrast of weakly luminescent micro-droplets, (3) an red maximizing inter-class variance thresholding method (OTSU) to segment the enhanced image for getting the binary map of the overall micro-droplets, (4) a circular Hough transform (CHT) method to detect overall micro-droplets and (5) an intensity-mean-based thresholding segmentation method to extract the fluorescent micro-droplets. The experimental results of fluorescent micro-droplet images show that the average accuracy of our micro-droplet detection method is 0.9586; the average true positive rate is 0.9502; and the average false positive rate is 0.0073. The detection method can be successfully applied to measure AP-labeled nanoparticle concentration in fluorescence microscopy.

  14. An electron microscopy based method for the detection and quantification of nanomaterial number concentration in environmentally relevant media

    International Nuclear Information System (INIS)

    Prasad, A.; Lead, J.R.; Baalousha, M.

    2015-01-01

    Improved detection and characterization of nanomaterials (NMs) in complex environmental media requires the development of novel sampling approaches to improve the detection limit to be close to environmentally realistic concentrations. Transmission electron microscopy (TEM) is an indispensable metrological tool in nanotechnology and environmental nanoscience due to its high spatial resolution and analytical capabilities when coupled to spectroscopic techniques. However, these capabilities are hampered by the conventional sample preparation methods, which suffer from low NM recovery. The current work presents a validated, fully quantitative sampling technique for TEM that overcomes conventional sample preparation shortcomings, and thus enables the use of TEM for measurement of particle number concentration and their detection in complex media at environmentally realistic concentrations. This sampling method is based on ultracentrifugation of NMs from suspension onto a poly-L-lysine (PLL) functionalized TEM grid, using active deposition (by ultracentrifugation) and retention (by PLL interactions with NM surface) of NMs on the substrate, enabling fully quantitative analysis. Similar analysis with AFM was satisfactory in simple media but the lack of chemical-selectivity of AFM limits its applicability for the detection of NMs in complex environmental samples. The sampling approach was validated using both citrate- and PVP-coated AuNMs in pure water, which demonstrated an even distribution of NM on the TEM grid and high NM recovery (80–100%) at environmentally relevant NM concentrations (ca. 0.20–100 μg L −1 ). The applicability of the sampling method to complex environmental samples was demonstrated by the quantification of particle number concentration of AuNMs in EPA soft water (with and without Suwannee River fulvic acid) and lake water. This sample preparation approach is also applicable to other types of NMs with some modifications (e.g. centrifugation

  15. An electron microscopy based method for the detection and quantification of nanomaterial number concentration in environmentally relevant media

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, A. [School of Geography, Earth and Environmental Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Lead, J.R., E-mail: jlead@mailbox.sc.edu [School of Geography, Earth and Environmental Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Center for Environmental Nanoscience and Risk, Department of Environmental Health Sciences, Arnold School of Public Health, University South Carolina, Columbia 29208, SC (United States); Baalousha, M., E-mail: mbaalous@mailbox.sc.edu [Center for Environmental Nanoscience and Risk, Department of Environmental Health Sciences, Arnold School of Public Health, University South Carolina, Columbia 29208, SC (United States)

    2015-12-15

    Improved detection and characterization of nanomaterials (NMs) in complex environmental media requires the development of novel sampling approaches to improve the detection limit to be close to environmentally realistic concentrations. Transmission electron microscopy (TEM) is an indispensable metrological tool in nanotechnology and environmental nanoscience due to its high spatial resolution and analytical capabilities when coupled to spectroscopic techniques. However, these capabilities are hampered by the conventional sample preparation methods, which suffer from low NM recovery. The current work presents a validated, fully quantitative sampling technique for TEM that overcomes conventional sample preparation shortcomings, and thus enables the use of TEM for measurement of particle number concentration and their detection in complex media at environmentally realistic concentrations. This sampling method is based on ultracentrifugation of NMs from suspension onto a poly-L-lysine (PLL) functionalized TEM grid, using active deposition (by ultracentrifugation) and retention (by PLL interactions with NM surface) of NMs on the substrate, enabling fully quantitative analysis. Similar analysis with AFM was satisfactory in simple media but the lack of chemical-selectivity of AFM limits its applicability for the detection of NMs in complex environmental samples. The sampling approach was validated using both citrate- and PVP-coated AuNMs in pure water, which demonstrated an even distribution of NM on the TEM grid and high NM recovery (80–100%) at environmentally relevant NM concentrations (ca. 0.20–100 μg L{sup −1}). The applicability of the sampling method to complex environmental samples was demonstrated by the quantification of particle number concentration of AuNMs in EPA soft water (with and without Suwannee River fulvic acid) and lake water. This sample preparation approach is also applicable to other types of NMs with some modifications (e.g. centrifugation

  16. Method for obtaining silver nanoparticle concentrations within a porous medium via synchrotron X-ray computed microtomography.

    Science.gov (United States)

    Molnar, Ian L; Willson, Clinton S; O'Carroll, Denis M; Rivers, Mark L; Gerhard, Jason I

    2014-01-21

    Attempts at understanding nanoparticle fate and transport in the subsurface environment are currently hindered by an inability to quantify nanoparticle behavior at the pore scale (within and between pores) within realistic pore networks. This paper is the first to present a method for high resolution quantification of silver nanoparticle (nAg) concentrations within porous media under controlled experimental conditions. This method makes it possible to extract silver nanoparticle concentrations within individual pores in static and quasi-dynamic (i.e., transport) systems. Quantification is achieved by employing absorption-edge synchrotron X-ray computed microtomography (SXCMT) and an extension of the Beer-Lambert law. Three-dimensional maps of X-ray mass linear attenuation are converted to SXCMT-determined nAg concentration and are found to closely match the concentrations determined by ICP analysis. In addition, factors affecting the quality of the SXCMT-determined results are investigated: 1) The acquisition of an additional above-edge data set reduced the standard deviation of SXCMT-determined concentrations; 2) X-ray refraction at the grain/water interface artificially depresses the SXCMT-determined concentrations within 18.1 μm of a grain surface; 3) By treating the approximately 20 × 10(6) voxels within each data set statistically (i.e., averaging), a high level of confidence in the SXCMT-determined mean concentrations can be obtained. This novel method provides the means to examine a wide range of properties related to nanoparticle transport in controlled laboratory porous medium experiments.

  17. Evaluation of missing value methods for predicting ambient BTEX concentrations in two neighbouring cities in Southwestern Ontario Canada

    Science.gov (United States)

    Miller, Lindsay; Xu, Xiaohong; Wheeler, Amanda; Zhang, Tianchu; Hamadani, Mariam; Ejaz, Unam

    2018-05-01

    High density air monitoring campaigns provide spatial patterns of pollutant concentrations which are integral in exposure assessment. Such analysis can assist with the determination of links between air quality and health outcomes, however, problems due to missing data can threaten to compromise these studies. This research evaluates four methods; mean value imputation, inverse distance weighting (IDW), inter-species ratios, and regression, to address missing spatial concentration data ranging from one missing data point up to 50% missing data. BTEX (benzene, toluene, ethylbenzene, and xylenes) concentrations were measured in Windsor and Sarnia, Ontario in the fall of 2005. Concentrations and inter-species ratios were generally similar between the two cities. Benzene (B) was observed to be higher in Sarnia, whereas toluene (T) and the T/B ratios were higher in Windsor. Using these urban, industrialized cities as case studies, this research demonstrates that using inter-species ratios or regression of the data for which there is complete information, along with one measured concentration (i.e. benzene) to predict for missing concentrations (i.e. TEX) results in good agreement between predicted and measured values. In both cities, the general trend remains that best agreement is observed for the leave-one-out scenario, followed by 10% and 25% missing, and the least agreement for the 50% missing cases. In the absence of any known concentrations IDW can provide reasonable agreement between observed and estimated concentrations for the BTEX species, and was superior over mean value imputation which was not able to preserve the spatial trend. The proposed methods can be used to fill in missing data, while preserving the general characteristics and rank order of the data which are sufficient for epidemiologic studies.

  18. Method and apparatus for detecting dilute concentrations of radioactive xenon in samples of xenon extracted from the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Warburton, William K.; Hennig, Wolfgang G.

    2018-01-02

    A method and apparatus for measuring the concentrations of radioxenon isotopes in a gaseous sample wherein the sample cell is surrounded by N sub-detectors that are sensitive to both electrons and to photons from radioxenon decays. Signal processing electronics are provided that can detect events within the sub-detectors, measure their energies, determine whether they arise from electrons or photons, and detect coincidences between events within the same or different sub-detectors. The energies of detected two or three event coincidences are recorded as points in associated two or three-dimensional histograms. Counts within regions of interest in the histograms are then used to compute estimates of the radioxenon isotope concentrations. The method achieves lower backgrounds and lower minimum detectable concentrations by using smaller detector crystals, eliminating interference between double and triple coincidence decay branches, and segregating double coincidences within the same sub-detector from those occurring between different sub-detectors.

  19. Setting-up and validation of two radioimmunoassay methods for determination of plasma progesterone concentration in mares, cows and rats

    International Nuclear Information System (INIS)

    Rosa e Silva, A.A.M.; Caldas, M.C.S.; Campos, L.M.A.; Gradela, A.

    1993-01-01

    Two reliable radioimmunoassay (RIA) methods which permits the measurement of progesterone (P 4 ) in plasma of equine, bovine and rats are described. After extraction of plasma with diethylic ether the RIA methods were performed. The first one utilizes 125 I progesterone (double antibody method) and the other 1,2,6,7,16, 17 3 H progesterone (adsorption in charcoal/dextran). Both two methods were suitable in the valuation of plasma P 4 concentration in different physiological reproductive conditions. The method of the double antibody showed higher sensibility beyond to be less expensive than the other method. Despite it, the two RIA methods were much less expensive than available commercial Kits in the market. (author)

  20. Platelet activation during preparation of platelet concentrates: a comparison of the platelet-rich plasma and the buffy coat methods

    NARCIS (Netherlands)

    Fijnheer, R.; Pietersz, R. N.; de Korte, D.; Gouwerok, C. W.; Dekker, W. J.; Reesink, H. W.; Roos, D.

    1990-01-01

    The activation of platelets during the preparation of platelet concentrates (PCs) by two methods was compared. To eliminate interdonor differences, 2 units of whole blood were pooled and subsequently divided into two batches. From one batch, the platelets were harvested as pelleted platelets from

  1. Effect of sample preparation methods on photometric determination of the tellurium and cobalt content in the samples of copper concentrates

    Directory of Open Access Journals (Sweden)

    Viktoriya Butenko

    2016-03-01

    Full Text Available Methods of determination of cobalt and nickel in copper concentrates currently used in factory laboratories are very labor intensive and time consuming. The limiting stage of the analysis is preliminary chemical sample preparation. Carrying out the decomposition process of industrial samples with concentrated mineral acids in open systems does not allow to improve the metrological characteristics of the methods, for this reason improvement the methods of sample preparation is quite relevant and has a practical interest. The work was dedicated to the determination of the optimal conditions of preliminary chemical preparation of copper concentrate samples for the subsequent determination of cobalt and tellurium in the obtained solution using tellurium-spectrophotometric method. Decomposition of the samples was carried out by acid dissolving in individual mineral acids and their mixtures by heating in an open system as well as by using ultrasonification and microwave radiation in a closed system. In order to select the optimal conditions for the decomposition of the samples in a closed system the phase contact time and ultrasonic generator’s power were varied. Intensification of the processes of decomposition of copper concentrates with nitric acid (1:1, ultrasound and microwave radiation allowed to transfer quantitatively cobalt and tellurium into solution spending 20 and 30 min respectively. This reduced the amount of reactants used and improved the accuracy of determination by running the process in strictly identical conditions.

  2. Artemether-Lumefantrine Concentrations in Tablets and Powders from Ghana Measured by a New High-Performance Liquid Chromatography Method

    DEFF Research Database (Denmark)

    Debrah, Philip; Nettey, Henry; Miltersen, Katja Kjeldgaard

    2016-01-01

    (deviation of mean from actual concentrations 99%). The validated method was used to analyze 24 batches of fixed-dose tablets and PSs of artemether and lumefantrine. Of the samples, 23 were obtained using convenience sampling of commonly available brands within Accra...

  3. Transport Phenomena Projects: Natural Convection between Porous, Concentric Cylinders--A Method to Learn and to Innovate

    Science.gov (United States)

    Saatadjian, Esteban; Lesage, Francois; Mota, Jose Paulo B.

    2013-01-01

    A project that involves the numerical simulation of transport phenomena is an excellent method to teach this subject to senior/graduate chemical engineering students. The subject presented here has been used in our senior/graduate course, it concerns the study of natural convection heat transfer between two concentric, horizontal, saturated porous…

  4. Load Concentration Factor Based Analytical Method for Optimal Placement of Multiple Distribution Generators for Loss Minimization and Voltage Profile Improvement

    NARCIS (Netherlands)

    Shahzad, Mohsin; Ahmad, Ishtiaq; Gawlik, Wolfgang; Palensky, P.

    2016-01-01

    This paper presents novel separate methods for finding optimal locations, sizes of multiple distributed generators (DGs) simultaneously and operational power factor in order to minimize power loss and improve the voltage profile in the distribution system. A load concentration factor (LCF) is

  5. An electrochemical method for determining hydrogen concentrations in metals and some applications

    Science.gov (United States)

    Danford, M. D.

    1983-01-01

    An electrochemical method was developed for the determination of hydrogen in metals using the EG&G-PARC Model 350A Corrosion Measurement Console. The method was applied to hydrogen uptake, both during electrolysis and electroplating, and to studies of hydrogen elimination and the effect of heat treatment on elimination times. Results from these studies are presented.

  6. An efficient way to prepare silver nanorods in high concentration by polyol method without adding other metal or salt

    International Nuclear Information System (INIS)

    Chen Yong; Guan Jianguo; Xie Hongquan

    2012-01-01

    Using ethylene glycol as solvent and reductant, polyvinyl pyrrolidone(PVP) as capping agent under the action of appropriately preformed silver crystal seeds and controlled addition rates of silver nitrate and PVP solution, silver nanorods with length of 2–15 μm and diameter of 200–880 nm can be obtained in high concentration of AgNO 3 as 0.50 M. In the absence of the preformed seeds, nanorods cannot be obtained as the main product, if the AgNO 3 concentration is over 0.10 M. It is necessary to use the appropriately preformed silver crystal seeds for the high concentration preparation of silver nanorods. Transmission Electron Microscopy images showed that Ag seeds preformed at appropriate silver nitrate concentrations exhibited the multiply twinned particles of decahedral shape(MTPs), which formed Ag nanorods in the presence of PVP. Through study of the effects of various factors on the nanostructure of silver, the favorable conditions are: appropriately preformed seeds concentration at 6.54–9.81 mM, addition rate of AgNO 3 solution at 0.30–0.43 mL min −1 and molar ratio of PVP/AgNO 3 at 1.1–1.4, in order to control the crystal growth rate of silver matching the reduction rate of AgNO 3 by ethylene glycol. The nanorods obtained were characterized by Scanning Electron Microscopy, EDX, XRD, Raman spectrometry, Infrared Spectrophotometry and Ultraviolet Spectrophotometry. On the base of the above results, the mechanism of rates matching for obtaining silver nanorods was briefly discussed. This method is a simple, facile and economical method using high concentration with high yield without using other metal or salt to massively synthesize silver nanorods through adding preformed silver seeds to control the reduction rate of silver nitrate and the crystal growth rate of silver nanorods. As compared to the conventional polyol method using lower silver nitrate concentration, this method can save ethylene glycol used and time of operation and the as

  7. Simulation of laminar and turbulent concentric pipe flows with the isogeometric variational multiscale method

    KAUST Repository

    Ghaffari Motlagh, Yousef

    2013-01-01

    We present an application of the residual-based variational multiscale modeling methodology to the computation of laminar and turbulent concentric annular pipe flows. Isogeometric analysis is utilized for higher-order approximation of the solution using Non-Uniform Rational B-Splines (NURBS). The ability of NURBS to exactly represent curved geometries makes NURBS-based isogeometric analysis attractive for the application to the flow through annular channels. We demonstrate the applicability of the methodology to both laminar and turbulent flow regimes. © 2012 Elsevier Ltd.

  8. Ion mobility spectrometry as a simple and rapid method to measure the plasma propofol concentrations for intravenous anaesthesia monitoring

    Science.gov (United States)

    Wang, Xin; Zhou, Qinghua; Jiang, Dandan; Gong, Yulei; Li, Enyou; Li, Haiyang

    2016-11-01

    The plasma propofol concentration is important information for anaesthetists to monitor and adjust the anaesthesia depth for patients during a surgery operation. In this paper, a stand-alone ion mobility spectrometer (IMS) was constructed for the rapid measurement of the plasma propofol concentrations. Without any sample pre-treatment, the plasma samples were dropped on a piece of glass microfiber paper and then introduced into the IMS cell by the thermal desorption directly. Each individual measurement could be accomplished within 1 min. For the plasma propofol concentrations from 1 to 12 μg mL-1, the IMS response was linear with a correlation coefficient R2 of 0.998, while the limit of detection was evaluated to be 0.1 μg mL-1. These measurement results did meet the clinical application requirements. Furthermore, other clinically-often-used drugs, including remifentanil, flurbiprofen and atracurium, were found no significant interference with the qualitative and quantitative analysis of the plasma propofol. The plasma propofol concentrations measured by IMS were correlated well with those measured by the high performance liquid chromatography (HPLC). The results confirmed an excellent agreement between these two methods. Finally, this method was applied to monitor the plasma propofol concentrations for a patient undergoing surgery, demonstrating its capability of anaesthesia monitoring in real clinical environments.

  9. Standard Test Method for Calibration of Non-Concentrator Photovoltaic Secondary Reference Cells

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers calibration and characterization of secondary terrestrial photovoltaic reference cells to a desired reference spectral irradiance distribution. The recommended physical requirements for these reference cells are described in Specification E1040. Reference cells are principally used in the determination of the electrical performance of a photovoltaic device. 1.2 Secondary reference cells are calibrated indoors using simulated sunlight or outdoors in natural sunlight by reference to a primary reference cell previously calibrated to the same desired reference spectral irradiance distribution. 1.3 Secondary reference cells calibrated according to this test method will have the same radiometric traceability as the of the primary reference cell used for the calibration. Therefore, if the primary reference cell is traceable to the World Radiometric Reference (WRR, see Test Method E816), the resulting secondary reference cell will also be traceable to the WRR. 1.4 This test method appli...

  10. A Novel Method for Analysis of Dissolved Inorganic Carbon Concentration and δ13C by Cavity Ring-Down Spectroscopy

    Science.gov (United States)

    Smith, E.; Gonneea, M. E.; Boze, L. G.; Casso, M.; Pohlman, J.

    2017-12-01

    Dissolved inorganic carbon (DIC) is the largest pool of carbon in the oceans and is where about half of anthropogenic carbon dioxide (CO2) emissions are being sequestered. Determining the concentration and stable carbon isotopic content (δ13C) of DIC allows us to delineate carbon sources that contribute to marine DIC. A simple and reliable method for measuring DIC concentration and δ13C can be used to apportion contributions from external sources and identify effects from biogeochemical reactions that contribute or remove DIC. The U.S. Geological Survey has developed a discrete sample analysis module (DSAM) that interfaces to a Picarro G-2201i cavity ring-down spectrometer (CRDS, Picarro Inc.) to analyze CO2 and methane concentrations and δ13C from discrete gas samples. In this study, we adapted the USGS DSAM-CRDS analysis system to include an AutoMate prep device (Automate FX, Inc.) for analysis of DIC concentration and δ13C from aqueous samples. The Automate prep device was modified to deliver CO2 extracted from DIC to the DSAM, which conditions and transfers the gas to the CRDS. LabVIEW software (National Instruments) triggers the Automate Prep device, controls the DSAM and collects data from the CRDS. CO2 mass concentration data are obtained by numerical integration of the CO2 volumetric concentrations output by the CRDS and subsequent comparison to standard materials. CO2 carbon isotope values from the CRDS (iCO2) are converted to δ13C values using a slope and offset correction calibration procedure. The system design and operation was optimized using sodium bicarbonate (NaHCO3) standards and a certified reference material. Surface water and pore water samples collected from Sage Lot Pond, a salt marsh in Cape Cod MA, have been analyzed for concentration by coulometry and δ13C by isotope ratio mass spectrometry and will be used to validate the DIC-DSAM-CRDS method for field applications.

  11. Sampling method, storage and pretreatment of sediment affect AVS concentrations with consequences for bioassay responses

    Energy Technology Data Exchange (ETDEWEB)

    Lange, H.J. de [Aquatic Ecology and Water Quality Management Group, Wageningen University, Wageningen University and Research Centre, P.O. Box 8080, 6700 DD, Wageningen (Netherlands); Centre for Ecosystem Studies, Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA, Wageningen (Netherlands)], E-mail: marieke.delange@wur.nl; Griethuysen, C. van; Koelmans, A.A. [Aquatic Ecology and Water Quality Management Group, Wageningen University, Wageningen University and Research Centre, P.O. Box 8080, 6700 DD, Wageningen (Netherlands)

    2008-01-15

    Sediment treatment and sediment storage may alter sediment toxicity, and consequently biotic response. Purpose of our study was to combine these three aspects (treatment-toxicity-biotic response) in one integrated approach. We used Acid Volatile Sulfide (AVS) concentrations as a proxy of the disturbance of the sediment. AVS and Simultaneously Extracted Metal (SEM) concentrations were compared to bioassay responses with the freshwater benthic macroinvertebrate Asellus aquaticus. Storage conditions and sediment treatment affected AVS but not SEM levels. AVS can be used as a proxy for sediment disturbance. The best way to pretreat the sediment for use in a bioassay in order to maintain initial AVS conditions was to sample the sediment with an Ekman grab, immediately store it in a jar without headspace, and freeze it as soon as possible. In a survey using seven different sediments, bioassay responses of A. aquaticus were correlated with SEM and AVS characteristics. - Change in AVS is a good proxy for sediment disturbance and combined with SEM it can be used as a suitable predictor for biotic effects of sediment contamination.

  12. Impedimetric method for measuring ultra-low E. coli concentrations in human urine.

    Science.gov (United States)

    Settu, Kalpana; Chen, Ching-Jung; Liu, Jen-Tsai; Chen, Chien-Lung; Tsai, Jang-Zern

    2015-04-15

    In this study, we developed an interdigitated gold microelectrode-based impedance sensor to detect Escherichia coli (E. coli) in human urine samples for urinary tract infection (UTI) diagnosis. E. coli growth in human urine samples was successfully monitored during a 12-h culture, and the results showed that the maximum relative changes could be measured at 10Hz. An equivalent electrical circuit model was used for evaluating the variations in impedance characteristics of bacterial growth. The equivalent circuit analysis indicated that the change in impedance values at low frequencies was caused by double layer capacitance due to bacterial attachment and formation of biofilm on electrode surface in urine. A linear relationship between the impedance change and initial E. coli concentration was obtained with the coefficient of determination R(2)>0.90 at various growth times of 1, 3, 5, 7, 9 and 12h in urine. Thus our sensor is capable of detecting a wide range of E. coli concentration, 7×10(0) to 7×10(8) cells/ml, in urine samples with high sensitivity. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Modeling of Groundwater Resources Heavy Metals Concentration Using Soft Computing Methods: Application of Different Types of Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Meysam Alizamir

    2017-09-01

    Full Text Available Nowadays, groundwater resources play a vital role as a source of drinking water in arid and semiarid regions and forecasting of pollutants content in these resources is very important. Therefore, this study aimed to compare two soft computing methods for modeling Cd, Pb and Zn concentration in groundwater resources of Asadabad Plain, Western Iran. The relative accuracy of several soft computing models, namely multi-layer perceptron (MLP and radial basis function (RBF for forecasting of heavy metals concentration have been investigated. In addition, Levenberg-Marquardt, gradient descent and conjugate gradient training algorithms were utilized for the MLP models. The ANN models for this study were developed using MATLAB R 2014 Software program. The MLP performs better than the other models for heavy metals concentration estimation. The simulation results revealed that MLP model was able to model heavy metals concentration in groundwater resources favorably. It generally is effectively utilized in environmental applications and in the water quality estimations. In addition, out of three algorithms, Levenberg-Marquardt was better than the others were. This study proposed soft computing modeling techniques for the prediction and estimation of heavy metals concentration in groundwater resources of Asadabad Plain. Based on collected data from the plain, MLP and RBF models were developed for each heavy metal. MLP can be utilized effectively in applications of prediction of heavy metals concentration in groundwater resources of Asadabad Plain.

  14. A nine-point pH titration method to determine low-concentration VFA in municipal wastewater.

    Science.gov (United States)

    Ai, Hainan; Zhang, Daijun; Lu, Peili; He, Qiang

    2011-01-01

    Characterization of volatile fatty acid (VFA) in wastewater is significant for understanding the wastewater nature and the wastewater treatment process optimization based on the usage of Activated Sludge Models (ASMs). In this study, a nine-point pH titration method was developed for the determination of low-concentration VFA in municipal wastewater. The method was evaluated using synthetic wastewater containing VFA with the concentration of 10-50 mg/l and the possible interfering buffer systems of carbonate, phosphate and ammonium similar to those in real municipal wastewater. In addition, the further evaluation was conducted through the assay of real wastewater using chromatography as reference. The results showed that the recovery of VFA in the synthetic wastewater was 92%-102 and the coefficient of variance (CV) of reduplicate measurements 1.68%-4.72%. The changing content of the buffering substances had little effect on the accuracy of the method. Moreover, the titration method was agreed with chromatography in the determination of VFA in real municipal wastewater with R(2)= 0.9987 and CV =1.3-1.7. The nine-point pH titration method is capable of satisfied determination of low-concentration VFA in municipal wastewater.

  15. Analysis of copper concentration in human serum by application of total reflection X-ray fluorescence method.

    Science.gov (United States)

    Kubala-Kukuś, Aldona; Banaś, Dariusz; Braziewicz, Janusz; Majewska, Urszula; Pajek, Marek; Wudarczyk-Moćko, Jolanta; Antczak, Grażyna; Borkowska, Beata; Góźdź, Stanisław; Smok-Kalwat, Jolanta

    2014-04-01

    The chemotherapy and photon radiotherapy are the most often applied methods in treatment of the cancer diseases because of their effectiveness and high cure rates. Apart from eligible destruction of the tumour, one of the side effects of these treatment methods is possible modification of main and trace element concentration in different human tissues and fluids. In this paper, the copper (Cu) level in human serum was determined by total reflection X-ray fluorescence method in 142 chemotherapy patients and in 44 healthy persons being a control group. The Cu concentration in the chemotherapy group was found to be on the level 1.78 ± 0.909 mg/L, while in the control group, it was 1.08 ± 0.551 mg/L. Performed measurements allowed for calculation of the parameters of copper concentration distribution (mean value, standard deviation, median) for both analysed groups. The theoretical nature of the concentration distribution was tested and found as a log-normal distribution (control group) and a log-stable distribution (chemotherapy group). The copper concentration distributions for both studied group were statistically compared using Kolmogorov-Smirnov test, and the conclusion was that the distributions are statistically different. Serum Cu levels were significantly higher in the chemotherapy group than in the control group. Taking into account the results for the control group, the copper concentration reference quantile ranges in human serum were obtained. The values of the mean, median and other quantiles determined in this case can be applied in two-group comparison studies. The obtained results can be used as a diagnostic tool for chemotherapy patients.

  16. Defining an appropriate leucoreduction strategy by serial assessment of cytokine levels in platelet concentrates prepared by different methods

    Directory of Open Access Journals (Sweden)

    Daljit Kaur

    2015-01-01

    Full Text Available Background and Objectives: Different methods of platelet concentrate preparations leave behind certain number of residual leukocytes, accounting for most of the febrile nonhemolytic transfusion reactions, especially in multitransfused patients. Various inflammatory cytokines, such as tumor necrosis factor-α (TNF-α, interleukin-1β (IL-1β, and IL-6 are generated during storage and have been implicated for these adverse effects. We have studied the levels of these cytokines and their correlation with leucocyte contents in platelet concentrates prepared by three different methods. Study Design and Methods: Five pools of platelet rich plasma platelet concentrates (PRP-PC and buffy-coat platelet concentrates (BC-PC each were prepared and divided into two halves. One half of the pool was leucofiltered (LF, whereas the other half was stored as such. Ten apheresis units were also included in the study. All the platelet concentrates were assessed for leucocyte load and cytokine content (IL-1β, IL-6, and TNF-α on different days of storage (0, 3, and 5 using Nageotte chamber and commercially available immunoassays respectively. Results: There was a statistically significant rise in cytokine levels (IL-1β, IL-6, and TNF-α in nonleucofiltered (NLF random donor platelet concentrates (RDPs (PRP-PC and BC-PC during storage (day 3 and 5 whereas LF RDP concentrates (PRP-PC and BC-PC and apheresis platelet concentrates (AP-PC did not show any significant rise in cytokine levels (on day 3 and 5 over the baseline values at day 0. Conclusion: This data suggests that although AP-PCs are superior to PRP-PC (NLF and BC-PC (NLF in terms of in vitro quality control parameters and cytokine generation during storage, BC-PC mode of platelet preparation followed by leucofiltration is the best method to store platelets and minimise the cytokine accumulation. This strategy is best suited for transfusion in multitransfused hematooncologic patients, who cannot afford

  17. A sub-nationwide survey of outdoor and indoor 222Rn concentrations in China by passive method

    International Nuclear Information System (INIS)

    Jin Yihe; Ikebe, Y.; Iida, T.

    1996-01-01

    From Nov. 1988 to Mar. 1993, cooperated by China and Japan, a survey of outdoor and indoor 222 Rn concentrations in 10 cities which were highly populated in China was carried out by means of passive method. the annual mean of outdoor 222 Rn concentration in 10 cities was 8.8 Bq·m -3 . The highest of 13.5 Bq·m -3 was in Wuhan, the lowest of 3.3 Bq·m -3 was in Chongming Island of Shanghai; and there were no significant differences among the different years in the same areas. During the northwest wind seasons, about 50% of outdoor 222 Rn concentration in Taiwan was contributed by the airflow from the mainland. Typical apartment houses and offices built of brick and concrete were also surveyed for indoor 222 Rn concentration. The annual mean of indoor 222 Rn concentration in the 10 cities was 19.5 Bq·m - 3. The highest of 33.9 Bq·m -3 was observed in Guiyang, the lowest of 9.0 Bq·m -3 was observed in Chongming Island of Shanghai. The outdoor and indoor 222 Rn concentrations showed a clear seasonal pattern with the minimum in summer and the maximum in winter. And they also showed a clear geographic distribution tendency; they were higher in inland than in seashores, and higher in the south than in the north. The ratios of indoor to outdoor 222 Rn concentrations were from 1.1 to 4.6. The annual effective dose equivalents resulting from outdoor and indoor 222 Rn concentrations amounted to about 0.64 mSv·a -1 . The highest was in Guiyang, and the lowest was in Nantong, being 1.12 and 0.39 mSv·a -1 , respectively

  18. The efficiency of concentration methods used to detect enteric viruses in anaerobically digested sludge

    Directory of Open Access Journals (Sweden)

    Tatiana Prado

    2013-02-01

    Full Text Available The presence of enteric viruses in biosolids can be underestimated due to the inefficient methods (mainly molecular methods used to recover the viruses from these matrices. Therefore, the goal of this study was to evaluate the different methods used to recover adenoviruses (AdV, rotavirus species A (RVA, norovirus genogroup II (NoV GII and the hepatitis A virus (HAV from biosolid samples at a large urban wastewater treatment plant in Brazil after they had been treated by mesophilic anaerobic digestion. Quantitative polymerase chain reaction (PCR was used for spiking experiments to compare the detection limits of feasible methods, such as beef extract elution and ultracentrifugation. Tests were performed to detect the inhibition levels and the bacteriophage PP7 was used as an internal control. The results showed that the inhibitors affected the efficiency of the PCR reaction and that beef extract elution is a suitable method for detecting enteric viruses, mainly AdV from biosolid samples. All of the viral groups were detected in the biosolid samples: AdV (90%, RVA, NoV GII (45% and HAV (18%, indicating the viruses' resistance to the anaerobic treatment process. This is the first study in Brazil to detect the presence of RVA, AdV, NoV GII and HAV in anaerobically digested sludge, highlighting the importance of adequate waste management.

  19. Development and application of a sensitive method to determine concentrations of acrolein and other carbonyls in ambient air.

    Science.gov (United States)

    Cahill, Thomas M; Charles, M Judith; Seaman, Vincent Y

    2010-05-01

    Acrolein, an unsaturated aldehyde, has been identified as one of the most important toxic air pollutants in recent assessments of ambient air quality. Current methods for determining acrolein concentrations, however, suffer from poor sensitivity, selectivity, and reproducibility. The collection and analysis of unsaturated carbonyls, and acrolein in particular, is complicated by unstable derivatives, coelution of similar compounds, and ozone interference. The primary objective of this research was to develop an analytical method to measure acrolein and other volatile carbonyls present in low part-per-trillion concentrations in ambient air samples obtained over short sampling periods. The method we devised uses a mist chamber in which carbonyls from air samples form water-soluble adducts with bisulfite in the chamber solution, effectively trapping the carbonyls in the solution. The mist chamber methodology proved effective, with collection efficiency for acrolein of at least 70% for each mist chamber at a flow rate of approximately 17 L/min. After the sample collection, the carbonyls are liberated from the bisulfite adducts through the addition of hydrogen peroxide, which converts the bisulfite to sulfate, reversing the bisulfite addition reaction. The free carbonyls are then derivatized by o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA*), which stabilizes the analytes and makes them easier to detect by electron-capture negative ionization mass spectrometry (ECNI-MS). The derivatives are then extracted and analyzed by gas chromatography-mass spectrometry (GC-MS). The mist chamber method was applied in a field test to determine the extent of acrolein in ambient air near the Peace Bridge plaza in Buffalo, New York, an area of heavy traffic near a major border crossing between the United States and Canada. In addition, XAD-2 adsorbent cartridges coated with 2-(hydroxymethyl)piperidine (2-HMP) according to Occupational Safety and Health Administration (OSHA) Method

  20. Method and apparatus for determining uranium concentration in a moving stream

    International Nuclear Information System (INIS)

    Bartko, J.; Wonn, J.W.

    1977-01-01

    The concentration of uranium in a moving stream is determined by agglomerating background microbubbles out of the 6 to 10 micron size range, counting microbubbles in the stream which are about 6 to about 10 microns in size, exposing the stream to a radiation source to cause uranium fission fragments to produce microbubbles, counting microbubbles which are about 6 to about 10 microns in size, and subtracting one count from the other and multiplying by a calibration constant. The subtraction can be performed on an earlier first count so that both counts are made on the same volume. The radiation exposure can be automatically increased when the difference between the first and second counts is low

  1. Influence of the method of fluoride administration on toxicity and fluoride concentrations in Japanese quail

    Science.gov (United States)

    Fleming, W.J.; Schuler, C.A.

    1988-01-01

    Young Japanese quail (Coturnix japonica) were administered NaF for 16 d either in their diet or by esophageal intubation. Based on the total fluoride ion (Emg F-) intake over the l6-d experimental period, fluoride administered by intubation was at least six times more toxic than that fed in the diet. Dietary concentrations of 1,000 ppm F- (Emg F- for 16 d = approx. 144) produced no mortality, whereas intubated doses produced 73% or greater mortality in all groups administered 54 mg F- /kg/d or more (Emg F- for 16 d _ approx. 23 mg). GraphIc companson of the regression of log F- ppm in femurs/mg F- intake showed that fluoride levels in the femurs of quail administered fluoride by intubation were higher than in those administered fluoride in the diet.

  2. Recent developments in atom transfer radical polymerization (ATRP): methods to reduce metal catalyst concentrations.

    Science.gov (United States)

    Lou, Qin; Shipp, Devon A

    2012-10-08

    Atom transfer radical polymerization (ATRP) was initially developed in the mid-1990s, and with continued refinement and use has led to significant discoveries in new materials. However, metal contamination of the polymer product is an issue that has proven detrimental to widespread industrial application of ATRP. The laboratories of K. Matyjaszewski have made significant progress towards removing this impediment, leading the development of "activators regenerated by electron transfer" ATRP (ARGET ATRP) and electrochemically mediated ATRP (eATRP) technologies. These variants of ATRP allow polymers to be produced with great molecular weight and functionality control but at significantly reduced catalyst concentrations, typically at parts per million levels. This Concept examines these polymerizations in terms of their mechanism and outcomes, and is aimed at giving the reader an overview of recent developments in the field of ATRP. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Chemical looping fluidized-bed concentrating solar power system and method

    Science.gov (United States)

    Ma, Zhiwen

    2017-07-11

    A concentrated solar power (CSP) plant comprises a receiver configured to contain a chemical substance for a chemical reaction and an array of heliostats. Each heliostat is configured to direct sunlight toward the receiver. The receiver is configured to transfer thermal energy from the sunlight to the chemical substance in a reduction reaction. The CSP plant further comprises a first storage container configured to store solid state particles produced by the reduction reaction and a heat exchanger configured to combine the solid state particles and gas through an oxidation reaction. The heat exchanger is configured to transfer heat produced in the oxidation reaction to a working fluid to heat the working fluid. The CSP plant further comprises a power turbine coupled to the heat exchanger, such that the heated working fluid turns the power turbine, and a generator coupled to and driven by the power turbine to generate electricity.

  4. Standardization of a broth microdilution susceptibility testing method to determine minimum inhibitory concentrations of aquatic bacteria

    DEFF Research Database (Denmark)

    Miller, R.A.; Walker, R.D.; Carson, J.

    2005-01-01

    antimicrobial susceptibility testing methods for bacterial isolates from aquatic animal species. QC ranges were established for Escherichia coli ATCC 25922 and Aeromonas salmonicida subsp. salmonicida ATCC 33658 when testing at 22, 28 and 35 degrees C (E. coli only) for 10 different antimicrobial agents...

  5. Method for the determination of clay and mica concentrations in subsurface sandstone formations through radioactive logging

    International Nuclear Information System (INIS)

    Allen, L.S.

    1984-01-01

    A method is described for radioactivity well logging in a subsurface sandstone formation penetrated by a borehole. The invention relates particularly to clay and mica contents, which are determined from the natural gamma-ray activities. The natural sources of gamma radiation in the formation, are the trace elements thorium, uranium and potassium. (U.K.)

  6. Detection of protein concentrations using a pH-step titration method

    NARCIS (Netherlands)

    Kruise, J.; Kruise, J.; Eijkel, Jan C.T.; Bergveld, Piet

    1997-01-01

    A stimulus-response method based on the application of a pH step is proposed for the detection of protein immobilized in a membrane on top of an ion-sensitive field-effect transistor (ISFET). The ISFET response to a step-wise change in pH, applied at the interface between the membrane and the

  7. A non-invasive diffuse reflectance calibration-free method for absolute determination of exogenous biochemicals concentration in biological tissues

    Science.gov (United States)

    Lappa, Alexander V.; Kulikovskiy, Artem N.; Busarov, Oleg G.

    2014-03-01

    The paper presents a new method for distant non-destructive determination of concentration of light absorbing admixtures in turbid media. In particular, it is intended for non-invasive in vivo control of accumulation in patient tissues of various biochemicals introduced to the patients for chemotherapy, photodynamic therapy or diagnostics. It is require that the admixture absorption spectrum should have a clearly marked peak in the wavelength region where the pure medium one varies regularly. Fluorescence of admixtures is not required. The method uses the local diffuse reflectance spectroscopy with optical fiber probe including one emitting and two reading There are several features in the method: the value to be determined is absolute concentration of admixtures; the method needs no calibration measurements on phantoms; it needs no reference measurements on sample with zero admixture concentration; it uses a two parametric kinetic light propagation model and original algorithms to resolve direct and inverse tasks of radiation transport theory. Experimental testing passed with tissue equivalent phantoms and different admixtures, including a chlorine photosensitizer, showed accuracy under 10% in all cases.

  8. A high-throughput AO/PI-based cell concentration and viability detection method using the Celigo image cytometry.

    Science.gov (United States)

    Chan, Leo Li-Ying; Smith, Tim; Kumph, Kendra A; Kuksin, Dmitry; Kessel, Sarah; Déry, Olivier; Cribbes, Scott; Lai, Ning; Qiu, Jean

    2016-10-01

    To ensure cell-based assays are performed properly, both cell concentration and viability have to be determined so that the data can be normalized to generate meaningful and comparable results. Cell-based assays performed in immuno-oncology, toxicology, or bioprocessing research often require measuring of multiple samples and conditions, thus the current automated cell counter that uses single disposable counting slides is not practical for high-throughput screening assays. In the recent years, a plate-based image cytometry system has been developed for high-throughput biomolecular screening assays. In this work, we demonstrate a high-throughput AO/PI-based cell concentration and viability method using the Celigo image cytometer. First, we validate the method by comparing directly to Cellometer automated cell counter. Next, cell concentration dynamic range, viability dynamic range, and consistency are determined. The high-throughput AO/PI method described here allows for 96-well to 384-well plate samples to be analyzed in less than 7 min, which greatly reduces the time required for the single sample-based automated cell counter. In addition, this method can improve the efficiency for high-throughput screening assays, where multiple cell counts and viability measurements are needed prior to performing assays such as flow cytometry, ELISA, or simply plating cells for cell culture.

  9. Water vapor concentration measurement in singlet oxygen generator by using emission spectroscopy method and absorption at 1392nm

    Science.gov (United States)

    Zhao, Weili; Wang, Zengqiang; Fang, Benjie; Li, Qingwei; Jin, Yuqi; Sang, Fengting

    2005-12-01

    By using emission spectroscopy method and absorption at 1392nm, partial water pressure at the exit of a square pipe-array jet-type singlet oxygen generator (SPJSOG) for chemical oxygen-iodine laser (COIL) was measured. The water vapor fraction was calculated from the partial water pressure in the diagnostic cell when we assumed the water vapor fraction in the diagnostic cell is the same as that in the generator. The results from the two methods showed that the water vapor concentration is less than 0.08 in this SPJSOG during normal operation. The water vapor fraction decreases with the increasing of the pressure in the generator and rises with the increasing of buffer gas flow rate and the basic hydrogen peroxide (BHP) temperature in the case of constant chlorine flow rate. Measurements showed that the change of water vapor fraction due to BHP temperature could be ignored during normal operation. It is indicated that the gas flow velocity is the main reason that affects on the water vapor fraction in COIL. It is proved that the emission spectroscopy method is one of the simple and convenient ways to measure the water vapor concentration in singlet oxygen generator (SOG), especially in real time measurements. But absorption spectroscopy method, as a direct measurement, can give the more factual results of the water concentration.

  10. MACRONUTRIENT CONCENTRATION AND CONTENT IN PASSION FRUIT LEAVES UNDER SAMPLING METHODS AND N-K FERTILIZATION RATES

    Directory of Open Access Journals (Sweden)

    RODINEI FACCO PEGORARO

    2017-12-01

    Full Text Available ABSTRACT Nitrogen and potassium fertilization and assessment of adequate nutritional status are essential for increasing fruit production of passion fruit. However, studies related to characterization of the leaf nutrient concentration and content in passion fruit with different production capacities are scarce in the literature in Brazil. The objective of this study was to evaluate macronutrient leaf concentration and content in different parts of the reproductive shoot of yellow passion fruit subjected to different ratios of N and K fertilization. The study was conducted in a randomized block design, with three replications, following a 4 x 6 factorial arrangement consisting of four cultivars of yellow passion fruit (BRS Gigante Amarelo, IAC 275, BRS Ouro Vermelho, and BRS Sol do Cerrado and six application rates of N-K2O fertilizer (0-0, 50-125, 100-250, 150-375, 200-500, and 250-625 kg ha-1 year-1. Two leaf sampling methods were adopted (leaf located at a position adjacent to the fruit, and leaf located at the end of the reproductive branch for nutritional assessment. The leaf located at the adjacent position had lower N, P, K, Mg, and S concentration and higher Ca concentration than the concentrations observed in the standard leaf. However, the higher leaf dry matter in adjacent leaves resulted in increased macronutrient concentration/content. The increase in N-K fertilizations inhibited Ca and Mg content in the leaves adjacent to the fruit of the Gigante Amarelo, IAC, and Ouro Vermelho passion fruit cultivars, but did not affect Ca and Mg content in the standard leaf. The passion fruit cultivars showed different leaf nutrient contents after N-K fertilization, indicating variable nutritional demands and the need for specific diagnostic methods for each cultivar.

  11. Assessment of a colorimetric method for the measurement of low concentrations of peracetic acid and hydrogen peroxide in water.

    Science.gov (United States)

    Domínguez-Henao, Laura; Turolla, Andrea; Monticelli, Damiano; Antonelli, Manuela

    2018-06-01

    The recent growing interest in peracetic acid (PAA) as disinfectant for wastewater treatment demands reliable and readily-available methods for its measurement. In detail, the monitoring of PAA in wastewater treatment plants requires a simple, accurate, rapid and inexpensive measurement procedure. In the present work, a method for analyzing low concentrations of PAA, adapted from the US EPA colorimetric method for total chlorine, is assessed. This method employs N,N-diethyl-p-phenylelnediamine (DPD) in the presence of an excess of iodide in a phosphate buffer system. Pink colored species are produced proportionally to the concentration of PAA in the sample. Considering that PAA is available commercially as an equilibrium solution of PAA and hydrogen peroxide (H 2 O 2 ), a measurement method for H 2 O 2 is also investigated. This method, as the one for the determination of PAA, is also based on the oxidation of iodide to iodine, with the difference that ammonium molybdate Mo(VI) is added to catalyze the oxidation reaction between H 2 O 2 and iodide, quantifying the total peroxides (PAA+ H 2 O 2 ). The two methods are suitable for concentration ranges from about 0.1-1.65 mg L -1 and from about 0.3-3.3 mg L -1 , respectively for PAA and H 2 O 2 . Moreover, the work elucidates some relevant aspects related to the operational conditions, kinetics and the possible interference of H 2 O 2 on PAA measurement. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Analytical method of Kr-85 determination, using cryogenic concentration and separation and liquid scintillation counting

    International Nuclear Information System (INIS)

    Heras Iniquez, M.C.; Perez Garcia, M.M.; Grau Malonda, A.

    1983-01-01

    The method used in the Laboratory of the JEN for the determination of Kr-85 levels in gaseous effluents of nuclear power and in the atmosphere is described. Samples of air, collected in metallic cylinders, are introduced into a gas-solid chromatographic separation system which resolves Kr from the other air components. The separated Kr ia dissolved in a toluene based scintillation cocktail, and the Kr-85 content is determined by liquid scintillation counting. (Author)

  13. Method for producing high carrier concentration p-Type transparent conducting oxides

    Science.gov (United States)

    Li, Xiaonan; Yan, Yanfa; Coutts, Timothy J.; Gessert, Timothy A.; Dehart, Clay M.

    2009-04-14

    A method for producing transparent p-type conducting oxide films without co-doping plasma enhancement or high temperature comprising: a) introducing a dialkyl metal at ambient temperature and a saturated pressure in a carrier gas into a low pressure deposition chamber, and b) introducing NO alone or with an oxidizer into the chamber under an environment sufficient to produce a metal-rich condition to enable NO decomposition and atomic nitrogen incorporation into the formed transparent metal conducting oxide.

  14. Method for the concentration and separation of actinides from biological and environmental samples

    Science.gov (United States)

    Horwitz, E.P.; Dietz, M.L.

    1989-05-30

    A method and apparatus for the quantitative recover of actinide values from biological and environmental sample by passing appropriately prepared samples in a mineral acid solution through a separation column of a dialkyl(phenyl)-N,N-dialylcarbamoylmethylphosphine oxide dissolved in tri-n-butyl phosphate on an inert substrate which selectively extracts the actinide values. The actinide values can be eluted either as a group or individually and their presence quantitatively detected by alpha counting. 3 figs.

  15. Final Report-- A Novel Storage Method for Concentrating Solar Power Plants Allowing Storage at High Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Morris, Jeffrey F.

    2014-09-29

    The main objective of the proposed work was the development and testing of a storage method that has the potential to fundamentally change the solar thermal industry. The development of a mathematical model that describes the phenomena involved in the heat storage and recovery was also a main objective of this work. Therefore, the goal was to prepare a design package allowing reliable scale-up and optimization of design.

  16. Changes in the Concentrations of Corticoid Metabolites – The Effect of Stress, Diet and Analytical Method

    Directory of Open Access Journals (Sweden)

    Michaela Dušková

    2015-01-01

    Full Text Available A precisely measured corticoid level is important for decision-making in daily clinical practice. These levels can be influenced in the pre-analytical phase, when the effect of stress, timing, and diet can be important. The aim of this study was to elucidate optimal conditions for blood sampling as well as the choice of analytical methods, which they will be used in measuring of corticoids. By studying ten women, we focused on the influences of the stress of cannulation and a large lunchtime meal on cortisol, cortisone, aldosterone and corticosterone levels. We further compared results of cortisol measurements from RIA and LC-MS/MS. Stress from cannulation caused increase of cortisol, cortisone and corticosterone already, when the cannula was being inserted. This indicates that this increase is stimulated by fear of the blood withdrawing rather, than just by the needle insertion itself. The effect of stress on corticosterone disappeared after an hour, while effect on other corticoids was still apparent. Concerning the lunchtime meal, we found an increase in all measured corticoids between 11 and 12 o’clock. After the food, there were marked decreases in cortisone and aldosterone, while declining levels of cortisol and corticosterone had rather plateaus. We compared cortisol in 90 plasma samples measured by a commercial RIA kit and the LC-MS/MS method. Results from both methods showed a strong correlation (r=0.85. When measuring corticoid metabolites, the chosen analytical method, eliminating stress factors, and precisely timed blood sampling considering the daily rhythm and food intake are critical.

  17. Effect of Precursor Concentration of MgO nanostructure by using Sol-Gel Method

    Directory of Open Access Journals (Sweden)

    V.T. Srisuvetha

    2017-04-01

    Full Text Available MgO thin flims have been prepared on substrates by a novel and simple sol-gel method using magnesium nitrate and collusion as starting material.The MgO nano catalyst with good sensor crystallization were obtained after annealing at 100°C Magnesium oxide was prepared by sol-gel method. The method involves the hydrolysis of magnesium alkoxide in the presence of acid or basic catalysts followed by a Oxalic acid reaction. The synthesized solids were characterized by IR spectroscopy X-ray diffraction electron microscopy. Ultraviolet visible absorbance measurement photoluminescence and Raman scattering spectra. X-ray diffraction (XRD characterization showed the formation of smaller particles after sol gel irradiation the structure and morphology of the MgO particles were analyzed byXRD. These articles were used for FTIR spectroscopic measurement and spectra were collected. In EDS we calculated the peak intensity the SEM the images of metal oxide.UV (Ultra Violet refers to adsorption spectroscopy optical properties of assorption, band gap energy.This means if use light in the visible and adjacent ranges.

  18. Impedances of electrochemically impregnated nickel electrodes as functions of potential, KOH concentration, and impregnation method

    Science.gov (United States)

    Reid, Margaret A.

    1989-01-01

    Impedances of fifteen electrodes form each of the four U.S. manufactures were measured at 0.200 V vs. the Hg/HgO reference electrode. This corresponds to a voltage of 1.145 for a Ni/H2 cell. Measurements were also made of a representative sample of these at 0.44 V. At the higher voltage, the impedances were small and very similar, but at the lower voltage there were major differences between manufacturers. Electrodes from the same manufacturers showed only small differences. The impedances of electrodes from two manufacturers were considerably different in 26 percent KOH from those in 31 percent KOH. These preliminary results seen to correlate with the limited data from earlier life testing of cells from these manufacturers. The impedances of cells being tested for Space Station Freedom are being followed, and more impendance measurements of electrodes are being performed as functions of manufacturer, voltage, electrolyte concentration, and cycle history in hopes of finding better correlations of impedance with life.

  19. Determination of trace concentrations of aluminium in rice samples by INAA and PIGE methods

    International Nuclear Information System (INIS)

    Nanda, B.B.; Biswal, R.R.; Acharya, R.; Pujari, P.K.

    2015-01-01

    Aluminium is one of the toxic elements entering human body mainly through food and food products. Though its bioavailability is very less, it is necessary to evaluate its total concentrations in food and food products entering to the body through. In order to evaluate total aluminium contents in various food items for daily dietary intake of aluminum, authors have systematically planned to carry out experiments in various food items including rice. Rice is the main food in many parts of India as well as in Odisha. Rice samples under study belong to three categories; (i) various rice samples from local market, (ii) various rice samples grown in similar irrigation (soil and water) conditions and (iii) same variety of rice with different irrigation conditions. Solid samples (pre-cleaned) were powdered, homogenized and taken for analysis by two nuclear analytical techniques (NATs) namely instrumental neutron activation analysis (INAA) using reactor neutrons at BARC and particle induced gamma ray emission (PIGE) using 4 MeV proton beam (20 nA current) from 3 MV Tandetron at IOP, Bhubaneswar in conjunction with high resolution gamma-ray spectrometry. Samples of 10-50 mg for INAA and 250 mg (pelletized in cellulose) for PIGE were used for experiments. For INAA, samples were irradiated at PCF, Dhruva reactor for 1 minute

  20. Detecting and Identifying Industrial Gases by a Method Based on Olfactory Machine at Different Concentrations

    Directory of Open Access Journals (Sweden)

    Yunlong Sun

    2018-01-01

    Full Text Available Gas sensors have been widely reported for industrial gas detection and monitoring. However, the rapid detection and identification of industrial gases are still a challenge. In this work, we measure four typical industrial gases including CO2, CH4, NH3, and volatile organic compounds (VOCs based on electronic nose (EN at different concentrations. To solve the problem of effective classification and identification of different industrial gases, we propose an algorithm based on the selective local linear embedding (SLLE to reduce the dimensionality and extract the features of high-dimensional data. Combining the Euclidean distance (ED formula with the proposed algorithm, we can achieve better classification and identification of four kinds of gases. We compared the classification and recognition results of classical principal component analysis (PCA, linear discriminate analysis (LDA, and PCA + LDA algorithms with the proposed SLLE algorithm after selecting the original data and performing feature extraction. The experimental results show that the recognition accuracy rate of the SLLE reaches 91.36%, which is better than the other three algorithms. In addition, the SLLE algorithm provides more efficient and accurate responses to high-dimensional industrial gas data. It can be used in real-time industrial gas detection and monitoring combined with gas sensor networks.

  1. The Effect of Different Zinc Application Methods on Yield and Grain Zinc Concentration of Bread Wheat Varieties

    Directory of Open Access Journals (Sweden)

    Hatun Barut

    2017-08-01

    Full Text Available This study was carried out to elucidate the impacts of zinc (Zn treatments on growth, development, quality and yield of commonly sown bread wheat cultivars under field conditions of Çukurova Region. Three different bread wheat cultivars (Adana-99, Ceyhan-99 and Pandas were experimented in randomized complete blocks-split plots experimental design with 3 replications. Field experiments were performed by two different Zn application methods; via soil and via soil+foliage. In the both trials, 0, 5, 10, 20, 30, and 40 kg ha-1 pure Zn doses were applied to the soil. 0.4% ZnSO4.7H2O solution was used for foliar Zn applications. Current findings revealed that Zn treatments had significant effects on grain yield, grain Zn concentration, grain phosphorus (P concentration and thousand grain weight of bread wheat cultivars, but significant effects were not observed on grain protein concentrations. Soil+foliar Zn treatments were more effective in improving grain Zn concentrations. It was concluded that 10- 20 kg ha-1 Zn treatment was quite effective on grain Zn concentrations.

  2. Plasma concentrations of blood coagulation factor VII measured by immunochemical and amidolytic methods

    DEFF Research Database (Denmark)

    Bladbjerg, E-M; Gram, J; Jespersen, J

    2000-01-01

    :Ag) or estimated with an amidolytic method (FVII:Am). We have investigated whether FVII:Am is a valuable alternative to FVII:Ag. FVII:Ag and FVII:Am were measured in 147 plasma samples from blood donors, patients on oral anticoagulant therapy, postmenopausal women on hormone replacement therapy, in postprandial...... omitting the data from patients on oral anticoagulant therapy, with mean values of 113 U/ml for FVII:Ag and 110 U/ml for FVII:Am (p regression analysis, the intercept (alpha=-21.50) was different from zero (p

  3. A method for calculating regional cerebral blood flow from emission computed tomography of inert gas concentrations

    DEFF Research Database (Denmark)

    Celsis, P; Goldman, T; Henriksen, L

    1981-01-01

    Emission tomography of positron or gamma emitting inert gases allows calculation of regional cerebral blood flow (rCBF) in cross-sectional slices of human brain. An algorithm is presented for rCBF calculations from a sequence of time averaged tomograms using inhaled 133Xe. The approach is designed...... of four 1 min pictures and using a fixed value for the brain:blood partition coefficient, lambda. The method is essentially based on the bolus distribution principle, and it allows the estimation of blood flow in ischemic areas. Application to positron emission tomography is discussed....

  4. Influence of pH and salt concentration on functional properties of walnut protein from different extraction methods.

    Science.gov (United States)

    Hu, Haifang; Fan, Tao; Zhao, Xiaoyan; Zhang, Xiaowei; Sun, Yali; Liu, Hongkai

    2017-08-01

    The effect of pH and NaCl on solubility and functional properties of walnut proteins obtained through AOT reverse micelles, enzyme-assisted reverse micelles and aqueous phase extraction methods was investigated and compared. Extraction yield, foaming properties, water holding capacities of protein obtained through enzyme-assisted reverse micelles at pH 2-12 and NaCl concentration 0.1-1 M were significantly higher than those of the AOT reverse micelles and aqueous phase extracted two. The solubility of proteins by AOT reverse micelles and enzyme-assisted reverse micelles at certain pH and NaCl concentration had no significant difference, but was higher that of the aqueous buffer. Oil holding capacity of three proteins was 2.35, 3.96 and 1.08 cm 3 /g, respectively. At pH 6-12 and NaCl concentration 0.1-1 M, the emulsifying activity of protein from AOT reverse micelles was higher than those of other two methods, while the emulsifying stability of protein from enzyme-assisted reverse micelles was the highest. The functional properties of walnut proteins were affected by extraction methods. It indicated that the walnut protein might be potentially applied in food industry as a food ingredient.

  5. THE VISUALIZATION METHOD OF THE 3D CONCENTRATION DISTRIBUTION OF ASIAN DUST IN THE GOOGLE EARTH

    Directory of Open Access Journals (Sweden)

    W. Okuda

    2012-07-01

    Full Text Available The Asian dust (called "Kosa" in Japan transported from desert areas in the northern China often covers over East Asia in the late winter and spring seasons. In this study, first of all, for dust events observed at various places in Japan on April 1, 2007 and March 21, 2010, the long-range transport simulation of Asian dust from desert areas in the northern China to Japan is carried out. Next, the method for representing 3D dust clouds by means of the image overlay functionality provided in the Google Earth is described. Since it is very difficult to display 3D dust clouds along the curvature of the Earth on the global scale, the 3D dust cloud distributed at the altitude of about 6300m was divided into many thin layers, each of which is the same thickness. After each of layers was transformed to the image layer, each image layer was displayed at the appropriate altitude in the Google Earth. Thus obtained image layers were displayed every an hour in the Google Earth. Finally, it is shown that 3D Asian dust clouds generated by the method described in this study are represented as smooth 3D cloud objects even if we looked at Asian dust clouds transversely in the Google Earth.

  6. A method for the determination of potassium concentration in organic tissue samples

    International Nuclear Information System (INIS)

    Maciel, A.C.A.

    1976-12-01

    An original method has been developed to detect small variations of potassium in several samples of organic tissue. These variations are relative to elements that are biologically representative, such as carbon, oxygen, and nitrogen. The samples are irradiated with a beam of protons from a Van de Graaff accelerator (4MV). Vacancies are created in the K-shell of potassium, and x-rays are emitted when these vacancies are filled with outer electrons. These X-rays and the protons elastically scattered by the nuclei of carbon, nitrogen and oxygen are detected and their energy spectra are analysed by computer programs especially elaborated for this purpose. A technique for routine preparation of samples in the laboratory was developed including the production of aluminum support layers, and the preparation of organic tissue samples with a low temperature microtome. The unique features of this method are that it does not destroy the tissue, permitting further analysis with the microscope, and the normalization of the amount of potassium using other elements (C,O,N) instead of the total mass of the sample. (Author) [pt

  7. A Limited Sampling, Simple, and Useful Method for Determination of Glomerular Filtration Rate in Cats by Using a New Accurate HPLC Method to Measure Iohexol Plasmatic Concentrations

    Directory of Open Access Journals (Sweden)

    Meucci Valentina

    2013-01-01

    Full Text Available Glomerular filtration rate (GFR is still a highly underutilized tool in cats because available methods are not easy to be performed in clinical practice. Iohexol (IOX has been shown to be a useful and reliable marker of GFR both in animals and in humans. The aim of the present study was to develop a rapid and reliable method for measuring IOX in feline plasma and to evaluate the accuracy of limited sampling models to establish a low-cost and clinically suitable GFR test. IOX concentrations were determined by using a new HPLC-UV method. GFR was assessed as plasma clearance of IOX, which was calculated by dividing dose administered by area under the curve of plasmatic concentration versus time (AUC, and indexed to body weight (BW. Correlation and agreement analysis between the GFR values obtained by a seven-point clearance method and the GFR values determined by the application of simplified sample combinations indicated that the 3-blood sample clearance model (5, 30, and 60 min was the best simplified method because it provided an accurate GFR value in only one hour. The reported method is a simple and accurate way of GFR determination, which may be easily used in a clinical setting.

  8. Determination of subcellular concentrations of soluble carbohydrates in rose petals during opening by nonaqueous fractionation method combined with infiltration-centrifugation method.

    Science.gov (United States)

    Yamada, Kunio; Norikoshi, Ryo; Suzuki, Katsumi; Imanishi, Hideo; Ichimura, Kazuo

    2009-11-01

    Petal growth associated with flower opening depends on cell expansion. To understand the role of soluble carbohydrates in petal cell expansion during flower opening, changes in soluble carbohydrate concentrations in vacuole, cytoplasm and apoplast of petal cells during flower opening in rose (Rosa hybrida L.) were investigated. We determined the subcellular distribution of soluble carbohydrates by combining nonaqueous fractionation method and infiltration-centrifugation method. During petal growth, fructose and glucose rapidly accumulated in the vacuole, reaching a maximum when petals almost reflected. Transmission electron microscopy showed that the volume of vacuole and air space drastically increased with petal growth. Carbohydrate concentration was calculated for each compartment of the petal cells and in petals that almost reflected, glucose and fructose concentrations increased to higher than 100 mM in the vacuole. Osmotic pressure increased in apoplast and symplast during flower opening, and this increase was mainly attributed to increases in fructose and glucose concentrations. No large difference in osmotic pressure due to soluble carbohydrates was observed between the apoplast and symplast before flower opening, but total osmotic pressure was much higher in the symplast than in the apoplast, a difference that was partially attributed to inorganic ions. An increase in osmotic pressure due to the continued accumulation of glucose and fructose in the symplast may facilitate water influx into cells, contributing to cell expansion associated with flower opening under conditions where osmotic pressure is higher in the symplast than in the apoplast.

  9. GENE TRANSFER ON Betta imbellis THROUGH TRANSFECTION METHOD WITH DIFFERENT DNA CONCENTRATION

    Directory of Open Access Journals (Sweden)

    Eni Kusrini

    2016-12-01

    Full Text Available Big size betta (Giant have a high economic value compared to normal size betta, and over expression of growth hormone gene can produce giant fish.  As an initial step of giant transgenic betta productions, this study was conducted in order to obtain DNA plasmid concentration which provide higher hatching and survival rate of betta larvae.  Construction of PhGH pCcBA gene contains growth hormone gene of Siamese catfish (PhGH and it is controlled by the CCBA promoter. Betta imbellis broodstocks were spawned naturally, and embryos were collected 1-2 minutes after spawning time. One hundred embryos were dipped in 2 mL of transfectan X-treme gene which containp CcBA-PhGH construction genes (50 µg/mL, on room temperature for about 30 minutes. Treatments on this study were different transfectant : DNA plasmid ratiosnamely:A (0,75 µL: 0,25 µL; B (0,75 µL : 0,50 µL; C (0,75 µL: 0,75 µL, D as Control 1(without transfectant, 0,25 µL DNA; E.as Control 2(0,75 µL transfectant, without DNA, and Fas control 3 (without transfectant and without DNA. Every treatments was repeated three times.  Transfection embryos were hatched on a container (1L Volume. Study results showed that hatching rate and larvae survival rate  (4 days after hatching on treatment A were the same with the control, but slightly higher than B and C treatments. PCR analysis with DNA template showing that PhGH gene were found on embryos and larvae (pooled sample of treatment A, B and C. Furthermore, RT-PCR analysis showing the existence of mRNA PhGH expression on embryos and larvae (pooled sample. Therefore, embryo transfection with transfectant ratio 0,75 µL and  DNA 0,25 µLshowing the best results.

  10. Determination of Alanine concentration in Alanine-supercritical water mixture, using UNIQUAC methods and density functional theory

    Directory of Open Access Journals (Sweden)

    Vahid mohammadrezaee

    2016-12-01

    Full Text Available In the following paper, density functional method and Universal QUAsi-chemical (UNIQUA activity index model were applied to calculate the concentration of Alanine I supercritical water. B3LYB method and 6-311G+ (2D, 2P basic function were used to optimize the molecular structure of Alanine, water and Alanine water complex. Then, reaction parameters of UNIQUAC model were calculated, using formation energy values. PCM method and zeropoint energy were utilized to include solvent effect and BSSE effect respectively. The resulted errors indicate that the method in a fairly good agreement with the experimental data. Including SSE in the interaction parameter calculations reduces the total error significantly. According to our calculations theAlanine- water complex showed a negative deviation from Raoul’s law.

  11. [Measurements of vancomycin concentrations in the blood - a method of personalization the antibiotic therapy in patients with chronic kidney disease].

    Science.gov (United States)

    Pondel, Joanna; Krajewski, Piotr; Królikowska, Natalia; Tobiasz, Aleksandra; Augustyniak-Bartosik, Hanna; Hurkacz, Magdalena

    2017-04-21

    Therapeutic Drug Monitoring is a recognized method of personalizing treatment, having particular application in patients with chronic kidney disease who have frequent infections, requiring administration of vancomycin. International guidelines indicate the need to adjust the dose of the drug to the state of renal function. The recommended therapeutic ranges of minimum and maximum levels should be achieved in order to increase the effectiveness and safety of treatment. The aim of this study was to evaluate the usefulness of measuring the concentration of vancomycin in patients with chronic kidney disease due to bacterial infection. The study included 96 adult patients with chronic kidney disease of varying severity treated with vancomycin Patients were divided into 3 groups: treated by haemodialysis (hd), after renal transplantations (ktx), do not require renal replacement therapy (nef). In subjects were examined the minimum and maximum concentrations of vancomycin in steady-state and were compared with recommended therapeutic ranges. Statistically significant decrease of inflammatory markers was observed only in patients treated with dialysis. In the other groups not significant changes in values of inflammatory parameters were confirmed. Trough concentrations of vancomycin marked in patients were consistent with the recommendation of EUCAST, but exceeded the value recommended by the manufacturers of the drug. Considering absolute values of the minimum concentrations, only about 50% of patients achieved the therapeutic range (58% for recommendation EUCAST and 36% for the manufacturer's instructions). Peak concentration values indicated in dialyzed patients were below the prescribed range of 20-50 mg/l and averaged 17.7 mg / l. In the other subgroups they were correct. The rating of the absolute values of the peak concentrations of vancomycin also showed that only 46% (64% in the ktx, 30% - hd and 53% - nef) was within the recommended range, while 50% were

  12. Concentration solar power optimization system and method of using the same

    Science.gov (United States)

    Andraka, Charles E

    2014-03-18

    A system and method for optimizing at least one mirror of at least one CSP system is provided. The system has a screen for displaying light patterns for reflection by the mirror, a camera for receiving a reflection of the light patterns from the mirror, and a solar characterization tool. The solar characterization tool has a characterizing unit for determining at least one mirror parameter of the mirror based on an initial position of the camera and the screen, and a refinement unit for refining the determined parameter(s) based on an adjusted position of the camera and screen whereby the mirror is characterized. The system may also be provided with a solar alignment tool for comparing at least one mirror parameter of the mirror to a design geometry whereby an alignment error is defined, and at least one alignment unit for adjusting the mirror to reduce the alignment error.

  13. Influence of solid-liquid separation method parameters employed in soil leaching tests on apparent metal concentration.

    Science.gov (United States)

    Imoto, Yukari; Yasutaka, Tetsuo; Someya, Masayuki; Higashino, Kazuo

    2018-05-15

    Soil leaching tests are commonly used to evaluate the leachability of hazardous materials, such as heavy metals, from the soil. Batch leaching tests often enhance soil colloidal mobility and may require solid-liquid separation procedures to remove excess soil particles. However, batch leaching test results depend on particles that can pass through a 0.45μm membrane filter and are influenced by test parameters such as centrifugal intensity and filtration volume per filter. To evaluate these parameters, we conducted batch leaching experiments using metal-contaminated soils and focused on the centrifugal intensity and filtration volume per filter used in solid-liquid separation methods currently employed in standard leaching tests. Our experiments showed that both centrifugal intensity and filtration volume per filter affected the reproducibility of batch leaching tests for some soil types. The results demonstrated that metal concentrations in the filtrates significantly differed according to the centrifugal intensity when it was 3000 g for 2h or less. Increased filtration volume per filter led to significant decreases in filtrate metal concentrations when filter cakes formed during filtration. Comparison of the filtration tests using 0.10 and 0.45μm membrane filters showed statistically significant differences in turbidity and metal concentration. These findings suggest that colloidal particles were not adequately removed from the extract and contributed substantially to the apparent metal concentrations in the leaching test of soil containing colloidal metals. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  14. Effect of silver nitrate concentration of silver nanowires synthesized using a polyol method and their application as transparent conductive films

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jian-Yang [Department of Electronic Engineering, National Yunlin University of Science and Technology, Yunlin 640, Taiwan (China); Hsueh, Yu-Lee [Graduate School of Engineering Science and Technology, National Yunlin University of Science and Technology, Yunlin 640, Taiwan (China); Huang, Jung-Jie, E-mail: jjhuang@mail.dyu.edu.tw [Department of Industrial Engineering and Management, DaYeh University, Changhua 51591, Taiwan (China); Wu, Jia-Rung [Department of Computer Science and Information Engineering, Asia University, Taichung 413, Taiwan (China)

    2015-06-01

    Silver nanowires were synthesized using a polyol process by employing ethylene glycol, poly(N-vinylpyrrolidone), and silver nitrate as precursors. The concentration of silver nitrate was varied to study the resulting changes in aspect ratios of silver nanowires. The experimental results indicated that the growth characteristics of silver nanowires were affected by the synthesis temperature, the concentration of silver nitrate, and the rate at which silver nitrate was added. Field-emission scanning electron microscopy, UV–visible spectrophotometry, and X-ray diffractometry were employed to characterize the silver nanowires. As the concentration of silver nitrate was reduced, the diameters of the silver nanowires decreased, increasing the aspect ratio. The optimal diameter and length of the silver nanowires were 100 nm and 20 μm, respectively. A thin film composed of silver nanowires exhibited average transmittance of 92.15% at visible wavelengths and a sheet resistance of 20 Ω/sq; such a film could be used as a transparent conductive film in commercial applications. - Highlights: • Using a polyol method to synthesize of silver nanowire • Concentration effect of silver nitrate on the synthesis was discussed. • Seed precursors are not used during the silver nanowire synthesizing. • The silver nanowire diameter and length were 100 nm and 20 μm, respectively. • High transmittance and low sheet resistance of silver nanowire film can be obtained.

  15. Improved methylene blue two-phase titration method for determining cationic surfactant concentration in high-salinity brine.

    Science.gov (United States)

    Cui, Leyu; Puerto, Maura; López-Salinas, José L; Biswal, Sibani L; Hirasaki, George J

    2014-11-18

    The methylene blue (MB) two-phase titration method is a rapid and efficient method for determining the concentrations of anionic surfactants. The point at which the aqueous and chloroform phases appear equally blue is called Epton's end point. However, many inorganic anions, e.g., Cl(-), NO3(-), Br(-), and I(-), can form ion pairs with MB(+) and interfere with Epton's end point, resulting in the failure of the MB two-phase titration in high-salinity brine. Here we present a method to extend the MB two-phase titration method for determining the concentration of various cationic surfactants in both deionized water and high-salinity brine (22% total dissolved solid). A colorless end point, at which the blue color is completely transferred from the aqueous phase to the chloroform phase, is proposed as titration end point. Light absorbance at the characteristic wavelength of MB is measured using a spectrophotometer. When the absorbance falls below a threshold value of 0.04, the aqueous phase is considered colorless, indicating that the end point has been reached. By using this improved method, the overall error for the titration of a permanent cationic surfactant, e.g., dodecyltrimethylammonium bromide, in deionized (DI) water and high-salinity brine is 1.274% and 1.322% with limits of detection (LOD) of 0.149 and 0.215 mM, respectively. Compared to the traditional acid-base titration method, the error of this improved method for a switchable cationic surfactant, e.g., tertiary amine surfactant (Ethomeen C12), is 2.22% in DI water and 0.106% with LOD of 0.369 and 0.439 mM, respectively.

  16. Procedure manual for the estimation of average indoor radon-daughter concentrations using the radon grab-sampling method

    International Nuclear Information System (INIS)

    George, J.L.

    1986-04-01

    The US Department of Energy (DOE) Office of Remedial Action and Waste Technology established the Technical Measurements Center to provide standardization, calibration, comparability, verification of data, quality assurance, and cost-effectiveness for the measurement requirements of DOE remedial action programs. One of the remedial-action measurement needs is the estimation of average indoor radon-daughter concentration. One method for accomplishing such estimations in support of DOE remedial action programs is the radon grab-sampling method. This manual describes procedures for radon grab sampling, with the application specifically directed to the estimation of average indoor radon-daughter concentration (RDC) in highly ventilated structures. This particular application of the measurement method is for cases where RDC estimates derived from long-term integrated measurements under occupied conditions are below the standard and where the structure being evaluated is considered to be highly ventilated. The radon grab-sampling method requires that sampling be conducted under standard maximized conditions. Briefly, the procedure for radon grab sampling involves the following steps: selection of sampling and counting equipment; sample acquisition and processing, including data reduction; calibration of equipment, including provisions to correct for pressure effects when sampling at various elevations; and incorporation of quality-control and assurance measures. This manual describes each of the above steps in detail and presents an example of a step-by-step radon grab-sampling procedure using a scintillation cell

  17. Evaluation of the iodine concentration in serum and urine of hypothyroid males an inexpensive and rapid method

    International Nuclear Information System (INIS)

    Kandhro, G.A.; Kazi, T.G.; Sirajuddin; Afridi, H.I.; Baig, J.A.; Shah, A.Q.; Arain, M.B.

    2009-01-01

    The aim of present study was to evaluate the iodine/iodide status in biological samples (serum and urine) of 172 male hypothyroid patients (HPs) and their supplemental effects on thyroid hormones. For comparison purpose, non-goitrous subjects (n= 220) of same age group and socioeconomic status were also studied. A simple and rapid iodide-ion selective electrode (ISE) was used to measure the concentration of iodine in microwave assisted acid digested serum and urine samples. Quality control for the methodology was established with certified samples and with those obtained by conventional wet acid digestion method on the same certified reference materials (CRMs) and real samples. A linear calibration curve was obtained for a reasonable concentration range of the potassium iodide solutions. The mean concentration of iodine in the serum and urine samples of the HPs was significantly reduced as compared to control male subjects (p< 0.01). The low levels of free triiodothyronine and thyroxin were found in HPs than age matched healthy control (p< 0.005 and 0.002) respectively while high levels of thyroid stimulating hormone were observed in HPs (p< 0.008). The proposed method was relatively efficient as well as cost effective by using inexpensive equipment. It was observed that iodine in biological samples of HPs can play an important role in determining the severity of the hypothyroidism. (author)

  18. A PTV method based on ultrasound imaging and feature tracking in a low-concentration sediment-laden flow

    Science.gov (United States)

    Ma, Zhimin; Hu, Wenbin; Zhao, Xiaohong; Tao, Weiliang

    2018-02-01

    This study aims to provide a particle tracking velocimetry (PTV) method based on ultrasound imaging and feature-tracking in a low-concentration sediment-laden flow. A phased array probe is used to generate a 2D ultrasound image at different times. Then, the feature points are extracted to be tracked instead of the centroids of the particle image. In order to better identify the corresponding feature point, each feature is described by an oriented angle and its location. Then, a statistical interpolation procedure is used to yield the displacement vector on the desired grid point. Finally a correction procedure is adopted because the ultrasound image is sequentially acquired line by line through the field of view. A simple test experiment was carried out to evaluate the performance. The ultrasound PTV system was applied to a sediment-laden flow with a low concentration of 1‰, and the speed was up to 10 cm s-1. In comparison to optical particle image velocimetry (PIV), ultrasound imaging does not have a limitation in optical access. The feature-tracking method does not have a binarisation and segmentation procedure, which can result in overlapping particles or a serious loss of particle data. The feature-tracking algorithm improves the peak locking effect and measurement accuracy. Thus, the ultrasound PTV algorithm is a feasible alternative and is significantly more robust against gradients than the correlation-based PIV algorithms in a low-concentration sediment-laden fluid.

  19. Considerations on the activity concentration determination method for low-level waste packages and nuclide data comparison between different countries

    International Nuclear Information System (INIS)

    Kashiwagi, M.; Mueller, W.

    2000-01-01

    In low-level waste disposal, acceptable activity concentration limits are regulated for individual nuclides and groups of nuclides according to the conditions of each disposal site. Such regulated limits principally concern total alpha and beta /gamma activity as well as nuclides such as C-14, Ni-63, and Pu-238 which are long-lived and difficult to measure (hereinafter referred to as difficult-to-measure nuclides). Before waste packages are transported to the disposal site, the activities or activity concentrations of the regulated nuclides and groups of nuclides in the waste packages must be assessed and declared. A generally applicable theoretical method to determine these activities is lacking at present. Therefore, to meet this requirement, for NPP waste each country independently samples actual waste and carries out radiochemical analyses on these samples. The activity concentrations of difficult-to-measure nuclides are then determined by statistical correlation of the measured data between difficult-to-measure nuclides and Co-60 and Cs-137 which are measurable from outside the waste packages (hereinafter referred to as key nuclides). This method is called 'Scaling Factor Method'. It is widely adopted as a method for determining the activity concentrations of the limited nuclides in low-level waste packages from NPP, and it is also approved by responsible authorities in the respective country. In the past, each country independently determined scaling factors based on measurements on samples from the local NPPs. In the first part of this study, the possibility of an international scaling factor assessment using a database integrating data from different countries was studied by comparing radiochemical analysis data between Germany, Japan, and the United States. These countries have accumulated a large number of those nuclide data required to determine scaling factors. Statistical values such as correlation coefficients change with an accumulation of data. In

  20. The effect of temperature and chitosan concentration during storage on the growth of chitosan nanoparticle produced by ionic gelation method

    Science.gov (United States)

    Handani, Wenny Rinda; Sediawan, Wahyudi Budi; Tawfiequrrahman, Ahmad; Wiratni, Kusumastuti, Yuni

    2017-05-01

    The objective of this research was to get the mechanism of nano size chitosan particle growth during storage by observing the effect of temperature and initial concentration of chitosan. The products were analyzed using PSA to have the average of particle radius. Nanochitosan solution was prepared by ionic gelation method. This method is described as an electrostatic interaction between positively charged amine with negatively charged polyanion, such as tripolyphosphate (TPP). Chitosan was dissolved in 1% acetic acid and was stirred for 30 minutes. Tween 80 was added to avoid agglomeration. TPP was prepared by dissolving 0.336 g into distilled water. The nano size chitosan was obtained by mixing TPP and chitosan solution dropwise while stirring for 30 minutes. This step was done at 15°C and ambient temperature (about 30°C) and chitosan concentration 0.2%, 0.4% and 0.6%. The results show that temperature during ionic gelation process (15°C and 30°C) does not affect the initial size of the nanoparticles produced as well as the growth of the nanoparticles during storage. On the other hand, initial chitosan concentration strongly affects initial size of the nanoparticles produced and the growth of the nanoparticles during storage. The concentration of chitosan at 0.2%, 0.4%, 0.6% gave initial size of nanoparticle chitosan of 175.3 nm, 337.9 nm, 643.3 nm respectively. On the other hand, the growth mechanism of chitosan nanoparticle depended on its radius(R). At R500 nm, it is controlled by diffusion in the liquid film around the particles.

  1. Use of a pre-analysis osmolality normalisation method to correct for variable urine concentrations and for improved metabolomic analyses.

    Science.gov (United States)

    Chetwynd, Andrew J; Abdul-Sada, Alaa; Holt, Stephen G; Hill, Elizabeth M

    2016-01-29

    Metabolomics analyses of urine have the potential to provide new information on the detection and progression of many disease processes. However, urine samples can vary significantly in total solute concentration and this presents a challenge to achieve high quality metabolomic datasets and the detection of biomarkers of disease or environmental exposures. This study investigated the efficacy of pre- and post-analysis normalisation methods to analyse metabolomic datasets obtained from neat and diluted urine samples from five individuals. Urine samples were extracted by solid phase extraction (SPE) prior to metabolomic analyses using a sensitive nanoflow/nanospray LC-MS technique and the data analysed by principal component analyses (PCA). Post-analysis normalisation of the datasets to either creatinine or osmolality concentration, or to mass spectrum total signal (MSTS), revealed that sample discrimination was driven by the dilution factor of urine rather than the individual providing the sample. Normalisation of urine samples to equal osmolality concentration prior to LC-MS analysis resulted in clustering of the PCA scores plot according to sample source and significant improvements in the number of peaks common to samples of all three dilutions from each individual. In addition, the ability to identify discriminating markers, using orthogonal partial least squared-discriminant analysis (OPLS-DA), was greatly improved when pre-analysis normalisation to osmolality was compared with post-analysis normalisation to osmolality and non-normalised datasets. Further improvements for peak area repeatability were observed in some samples when the pre-analysis normalisation to osmolality was combined with a post-analysis mass spectrum total useful signal (MSTUS) or MSTS normalisation. Future adoption of such normalisation methods may reduce the variability in metabolomics analyses due to differing urine concentrations and improve the discovery of discriminating metabolites

  2. A pharmacodynamic analysis method to determine the relative importance of drug concentration and treatment time on effect.

    Science.gov (United States)

    Millenbaugh, N J; Wientjes, M G; Au, J L

    2000-01-01

    The pharmacodynamics of most drugs follow the empirical relationship, C(n) x T = h, where C is drug concentration, T is exposure time and h is drug exposure constant. The value of n indicates the relative importance of C and T in determining the effect. An n value greater than 1.0 indicates that for two infusions that produce the same C x T, a short infusion that delivers high concentrations over a short duration will produce a greater C(n) x T and therefore a greater effect, compared to a long infusion that delivers lower concentrations. The reverse is true for an n value less than 1.0 and would support the use of a slow infusion. Hence, it is important to determine the n values and whether the n value significantly differs from 1.0. This report describes a three-step method for this purpose. First, we obtained experimental data on the relationship between drug concentration, treatment time and effect, and analyzed the data with a three-dimensional surface response method to obtain the pharmacodynamic model parameters and the magnitude of data variability. The experiments used mitomycin C and two human cancer cell lines, i.e. bladder RT4 and pharynx FaDu cells. The n values obtained from four experiments ranged from 1.04 to 1.16 for FaDu cells and from 1.14 to 1.46 for RT4 cells. The variability in the effect data decreased from 11.9% at 0% effect to 6.14% at 100% effect. Second, these results were used with Monte Carlo simulations to generate 100 concentration-time-effect data sets, which contained randomly and normally distributed data variability comparable to the experimentally observed variability, for each experimentally determined n value. This is analogous to performing 100 experiments under the same experimental conditions. Third, we analyzed the simulated data sets to obtain 100 estimated n values. The frequency with which these estimated n values fell above or below 1.0 indicated the probability that the experimentally determined n value used in the

  3. A comparison of methods for monitoring low airborne concentrations of argon-41 and tritium, with MIT-PFC design applications

    International Nuclear Information System (INIS)

    McLoughlin, J.C.

    1990-08-01

    Two primary methods, GM- and NaI-detection, of airborne 41 Ar monitoring were compared experimentally to determine the lowest resolvable concentration given reasonable sample sizes. NaI-detectors provided a lower resolvable concentration than GM tubes, primarily due to energy resolution, which greatly reduced background noise. Airborne 3 H collection was compared for two primary collection and one ancillary method (direct condensation). All 3 H detection was performed via liquid scintillation. Tritium collection with water baths yielded higher collection efficiencies than dessicant traps for short sampling durations. As the length of the sampling duration increased, water traps yielded lower collection efficiencies than dessicant traps, primarily due to evaporation of water from the water traps. Direct condensation as a collection method of airborne 3 H was found unsuitable, since large amounts of gas were initially condensed, yet evaporated as the sample's coolant was removed. 41 Ar detection for the MIT-PFC was determined to be best provided by a low 40 K NaI crystal shielded with lead and steel. A Marinelli beaker was used as a monitoring volume to hold the effluent sample. 3 H monitoring at the MIT-PFC was fulfilled with dessicant traps to catalytically separate the [HTO] and [HT] fractions without the use of a carrier gas for the [HT

  4. Concept of a methodical process for the design of concentrating photovoltaic systems according to the context of use

    Science.gov (United States)

    González-Correa, David; Osorio-Gómez, Gilberto; Mejía-Gutiérrez, Ricardo

    2016-09-01

    Concentrating Photo Voltaic (CPV) systems maximize energy harvested from the sun with multi-junction solar cells of less area, reducing related implementation costs and reaching energy production thresholds up to 38,9 %. Nowadays, CPV systems are generally implemented in solar energy farms in a permanent location, however, these systems could be used in other dynamic contexts, such as vehicles or portable devices. In this way, mechanical and geometrical parameters related to manipulation, transportation and installation should be carefully considered at the design stage. Besides, each condition of use presents different variables affecting these parameters. In all, there is not an established architecture for these systems, opening up the possibility of radically changing their use, geometry and components. Therefore, a concept of a methodical process for designing of CPV systems is proposed in order to predict their behavior in terms of implementation and energy production. This might allow the development of robust concepts that can be adapted to different context of use as required, providing an itinerant character and thus extending the field of implementation of these systems beyond a static use. The relevant variables for the use of CPV systems are determined through experimentation considering the implementation of Fresnel lenses as light concentrators. This allows generating a structured design guide composed of different methods of measurement, selection and development. The methodical process is based on a perspective of functional modules considering needs, technical aspects and particular usage conditions of each design and it would provide appropriate guidelines in each circumstance.

  5. Optimization of Davies and Gray/NBL method used for determination of total uranium concentration in the safeguards destructive analysis

    International Nuclear Information System (INIS)

    Silva, Jose Wanderley S. da; Viana, Aline Gonzalez; Barros, Pedro Dionisio de; Cristiano, Barbara Fernandes G.

    2013-01-01

    One important activity conducted by the Brazilian State System of Accounting for and Control of Nuclear Materials - SSAC is to verify inventories of the nuclear facilities by nondestructive analysis and destructive analysis. For destructive analysis, the Safeguards Laboratory of Brazilian Nuclear Energy Commission - LASAL/CNEN has been applying the 'Davies and Gray/NBL' method in samples taken during inspections at nuclear facilities since 1984 in Brazil and Argentina. This method consists of the determination of total uranium concentration by potentiometric titration of uranium (IV) with a standard solution of potassium dichromate as oxidizing agent. This solution is prepared using a K 2 Cr 2 O 7 SRM 136e standard reference material (99.984 ±0.010) wt% certified by National Institute of Standard and Technology - NIST. The procedure also includes the calibration with primary uranium standards reference material (NBL CRM 112A). In order to reduce the consumption of K 2 Cr 2 O 7 and the other reagent involved in the procedure, without any loss in the performance of the method, a K 2 Cr 2 O 7 solution with half the regular concentration was prepared and used to test the uranium concentration in several aliquots with a content between 30 mg to 40 mg of uranium per gram of solution. After optimizing the parameters and procedure, it was possible to get the same performance as well. As a consequence, decreasing of the cost, the amount of waste and also a reduction in the titration time of each aliquot was achieved. Thus, this work describes all details in this research as well as the results and its evaluation. (author)

  6. In situ sampling and speciation method for measuring dissolved phosphite at ultratrace concentrations in the natural environment.

    Science.gov (United States)

    Han, Chao; Williams, Paul N; Ren, Jinghua; Wang, Zhaode; Fang, Xu; Xu, Di; Xie, Xianchuan; Geng, Jinju; Ma, Lena Q; Luo, Jun

    2018-06-15

    Phosphite (P +III ) is of emerging chemical interest due to its importance within the global phosphorus cycle. Yet, to date, precise/accurate measurements of P +III are still lacking due to the inherent analytical challenges linked to its instability/ease of oxidation and ultra-trace concentration. Here, we present the first in-situ sampling and speciation analysis method, for dissolved P +III , using the diffusive-gradients-in-thin-films (DGT) technique, combined with capillary-column-configured-dual-ion-chromatography (CC-DIC). Method optimization of the DGT elution regime, to simultaneously maximize desorption efficiency and CC-DIC sensitivity, along with the characterization of diffusion coefficients for P +III , were undertaken before full method validation. Laboratory-performance testing confirmed DGT-P +III acquisition to be independent of pH (3.0-10.0) and ionic strength (0-500 mM). The capacity for P +III was 45.8 μg cm -2 , while neither P +V (up to 10 mg L -1 ) nor As +V (up to 1 mg L -1 ) impacted the DGT-P +III measurement. This novel method's functionality stems from the herein confirmed speciation preservation and double pre-concentration of P +III , resulting in quantification limits as low as 7.44 ng L -1 for a 3-day deployment. Applications of this method in various terrestrial/aquatic environments were demonstrated and simultaneous profiles of P +III and P +V across a sediment-water interface were captured at mm resolution in two contrasting redox-mesocosm systems. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Influence of concentration, time and method of application of citric acid and sodium citrate in root conditioning

    Science.gov (United States)

    CAVASSIM, Rodrigo; LEITE, Fábio Renato Manzolli; ZANDIM, Daniela Leal; DANTAS, Andrea Abi Rached; RACHED, Ricardo Samih Georges Abi; SAMPAIO, José Eduardo Cezar

    2012-01-01

    Objective The aim of this study was to establish the parameters of concentration, time and mode of application of citric acid and sodium citrate in relation to root conditioning. Material and Methods A total of 495 samples were obtained and equally distributed among 11 groups (5 for testing different concentrations of citric acid, 5 for testing different concentrations of sodium citrate and 1 control group). After laboratorial processing, the samples were analyzed under scanning electron microscopy. A previously calibrated and blind examiner evaluated micrographs of the samples. Non-parametric statistical analysis was performed to analyze the data obtained. Results Brushing 25% citric acid for 3 min, promoted greater exposure of collagen fibers in comparison with the brushing of 1% citric acid for 1 minute and its topical application at 1% for 3 min. Sodium citrate exposed collagen fibers in a few number of samples. Conclusion Despite the lack of statistical significance, better results for collagen exposure were obtained with brushing application of 25% citric acid for 3 min than with other application parameter. Sodium citrate produced a few number of samples with collagen exposure, so it is not indicated for root conditioning. PMID:22858707

  8. Influence of concentration, time and method of application of citric acid and sodium citrate in root conditioning

    Directory of Open Access Journals (Sweden)

    Rodrigo Cavassim

    2012-06-01

    Full Text Available OBJECTIVES: The aim of this study was to establish the parameters of concentration, time and mode of application of citric acid and sodium citrate in relation to root conditioning. MATERIAL AND METHODS: A total of 495 samples were obtained and equally distributed among 11 groups (5 for testing different concentrations of citric acid, 5 for testing different concentrations of sodium citrate and 1 control group. After laboratorial processing, the samples were analyzed under scanning electron microscopy. A previously calibrated and blind examiner evaluated micrographs of the samples. Non-parametric statistical analysis was performed to analyze the data obtained. RESULTS: Brushing 25% citric acid for 3 min, promoted greater exposure of collagen fibers in comparison with the brushing of 1% citric acid for 1 minute and its topical application at 1% for 3 min. Sodium citrate exposed collagen fibers in a few number of samples. CONCLUSION: Despite the lack of statistical significance, better results for collagen exposure were obtained with brushing application of 25% citric acid for 3 min than with other application parameter. Sodium citrate produced a few number of samples with collagen exposure, so it is not indicated for root conditioning.

  9. Numerical evaluation of the five sensor probe method for measurement of local interfacial area concentration of cap bubbles

    International Nuclear Information System (INIS)

    Euh, D.J.; Yun, B.J.; Song, C.H.; Kwon, T.S.; Chung, M.K.; Lee, U.C.

    2000-01-01

    The interfacial area concentration (IAC) is one of the most important parameters in the two-fluid model for two-phase flow analysis. The IAC can be measured by a local conductivity probe method that uses the difference of conductivity between water and air/steam. The number of sensors in the conductivity probe may be differently chosen by considering the flow regime of two-phase flow. The four sensor conductivity probe method predicts the IAC without any assumptions of the bubble shape. The local IAC can be obtained by measuring the three dimensional velocity vector elements at the measuring point, and the directional cosines of the sensors. The five sensor conductivity probe method proposed in this study is based on the four sensor probe method. With the five sensor probe, the local IAC for a given referred measuring area of the probe can be predicted more exactly. In this paper, the mathematical approach of the five sensor probe method for measuring the IAC is described, and a numerical simulation is carried out for ideal cap bubbles of which the sizes and locations are determined by a random number generator. (author)

  10. [Determination of minimal concentrations of biocorrosion inhibitors by a bioluminescence method in relation to bacteria, participating in biocorrosion].

    Science.gov (United States)

    Efremenko, E N; Azizov, R E; Makhlis, T A; Abbasov, V M; Varfolomeev, S D

    2005-01-01

    By using a bioluminescence ATP assay, we have determined the minimal concentrations of some biocorrosion inhibitors (Katon, Khazar, VFIKS-82, Nitro-1, Kaspii-2, and Kaspii-4) suppressing most common microbial corrosion agents: Desulfovibrio desulfuricans, Desulfovibrio vulgaris, Pseudomonas putida, Pseudomonas fluorescens, and Acidithiobacillus ferrooxidans. The cell titers determined by the bioluminescence method, including not only dividing cells but also their dormant living counterparts, are two- to sixfold greater than the values determined microbiologically. It is shown that the bioluminescence method can be applied to determination of cell titers in samples of oil-field waters in the presence of iron ions (up to 260 mM) and iron sulfide (to 186 mg/l) and in the absence or presence of biocidal corrosion inhibitors.

  11. Development of a novel method for simultaneous concentration of viruses and protozoa from a single water sample.

    Science.gov (United States)

    Haramoto, Eiji; Katayama, Hiroyuki; Asami, Mari; Akiba, Michihiro

    2012-06-01

    A novel method, electronegative membrane-vortex (EMV) method, was developed for simultaneous concentration of viruses and protozoa from a single water sample. Viruses and protozoa in a water sample were mixed with a cation solution and adsorbed on an electronegative membrane. Concentrated virus and protozoa samples were obtained as supernatant and pellet fractions, respectively, by vigorous vortex mixing of the membrane and centrifugation of the eluted material. The highest recovery efficiencies of model microbes from river water and tap water by this EMV method were obtained using a mixed cellulose ester membrane with a pore size of 0.45 μm (Millipore) as the electronegative membrane and MgCl(2) as the cation solution. The recovery was 27.7-86.5% for poliovirus, 25.7-68.3% for coliphage Qβ, 28.0-60.0% for Cryptosporidium oocysts, and 35.0-53.0% for Giardia cysts. The EMV method detected successfully indigenous viruses and protozoa in wastewater and river water samples from the Kofu basin, Japan, showing an overall positive rate of 100% (43/43) for human adenovirus, 79% (34/43) for norovirus GI, 65% (28/43) for norovirus GII, 23% (10/43) for Cryptosporidium oocysts, and 60% (26/43) for Giardia cysts. By direct DNA sequencing, a total of four genotypes (AI, AII, B, and G) of Giardia intestinalis were identified in the water samples, indicating that the river water was contaminated with feces from various mammals, including humans. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Producing high-density high-molecular-weight polymer brushes by a "grafting to" method from a concentrated homopolymer solution.

    Science.gov (United States)

    Taylor, Warren; Jones, Richard A L

    2010-09-07

    Here, a new procedure and method are presented for the production of highly grafted polymer brushes. Thiol-terminated polyethylene oxide (PEO-SH) of molecular weight (M(w)) 20,000 (20k) is grafted to a gold surface from highly concentrated aqueous solutions of nonthiolated polyethylene oxide homopolymer. The M(w) and volume fraction of the homopolymer solution are varied in order to control the grafting density of the resulting PEO-SH brush. As a result, 20k M(w) PEO-SH brushes with grafting densities up to 0.3 chains/nm(2) are achieved, as determined by ellipsometry. Highly concentrated homopolymer solutions of volume fraction greater than approximately 12% and M(w) greater than approximately 938 produce near-ideal solvent conditions for the 20k M(w) PEO-SH chains; we have found that this facilitates the achievement of higher grafting densities of end-functionalized polymer brushes than would be possible from simple solutions. We propose this as a suitable method for applications where the grafting density of a brush surface must be accurately varied and controlled consistently. The effect of chemisorption time and cleaning procedure on the resulting brush grafting density are also explored.

  13. Influence of Bovine Whey Protein Concentrate and Hydrolysate Preparation Methods on Motility in the Isolated Rat Distal Colon

    Science.gov (United States)

    Dalziel, Julie E.; Anderson, Rachel C.; Bassett, Shalome A.; Lloyd-West, Catherine M.; Haggarty, Neill W.; Roy, Nicole C.

    2016-01-01

    Whey protein concentrate (WPC) and hydrolysate (WPH) are protein ingredients used in sports, medical and pediatric formulations. Concentration and hydrolysis methods vary for whey sourced from cheese and casein co-products. The purpose of this research was to investigate the influence of whey processing methods on in vitro gastrointestinal (GI) health indicators for colonic motility, epithelial barrier integrity and immune modulation. WPCs from casein or cheese processing and WPH (11% or 19% degree of hydrolysis, DH) were compared for their effects on motility in a 1 cm section of isolated rat distal colon in an oxygenated tissue bath. Results showed that WPC decreased motility irrespective of whether it was a by-product of lactic acid or mineral acid casein production, or from cheese production. This indicated that regardless of the preparation methodology, the whey protein contained components that modulate aspects of motility within the distal colon. WPH (11% DH) increased contractile frequency by 27% in a delayed manner and WPH (19% DH) had an immediate effect on contractile properties, increasing tension by 65% and frequency by 131%. Increased motility was associated with increased hydrolysis that may be attributed to the abundance of bioactive peptides. Increased frequency of contractions by WPH (19% DH) was inhibited (by 44%) by naloxone, implicating a potential involvement of opioid receptors in modulation of motility. Trans-epithelial electrical resistance and cytokine expression assays revealed that the WPC proteins studied did not alter intestinal barrier integrity or elicit any discernible immune response. PMID:27983629

  14. Preparation of high concentration polyaluminum chloride by chemical synthesis-membrane distillation method with self-made hollow fiber membrane.

    Science.gov (United States)

    Zhao, Changwei; Yan, Yong; Hou, Deyin; Luan, Zhaokun; Jia, Zhiping

    2012-01-01

    A method of direct contact membrane distillation (DCMD) with a self-made hollow polyvinylidene fluoride membrane was applied to prepare high concentration polyaluminum chloride (PACl) with high A1b content based on chemical synthesis. The permeate flux and A1 species distribution were investigated. The experimental results showed that the permeate flux decreased from 14 to 6 kg/(m2 x hr) at the end of the DCMD process, which can be mainly attributed to the formation of NaCl deposits on the membrane surface. The Alb content decreased slightly, only from 86.3% to 84.4%, when the DCMD experiment finished, correspondingly the A1c content increased slightly from 7.2% to 8.5%, and the A1a content remained at 7% during the whole DCMD process. A PACl with A1b content of 84% at total aluminum concentration 2.2 mol/L was successfully prepared by the chemical synthesis-DCMD method.

  15. Standard test method for determination of uranium or plutonium isotopic composition or concentration by the total evaporation method using a thermal ionization mass spectrometer

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This method describes the determination of the isotopic composition and/or the concentration of uranium and plutonium as nitrate solutions by the thermal ionization mass spectrometric (TIMS) total evaporation method. Purified uranium or plutonium nitrate solutions are loaded onto a degassed metal filament and placed in the mass spectrometer. Under computer control, ion currents are generated by heating of the filament(s). The ion beams are continually measured until the sample is exhausted. The measured ion currents are integrated over the course of the run, and normalized to a reference isotope ion current to yield isotopic ratios. 1.2 In principle, the total evaporation method should yield isotopic ratios that do not require mass bias correction. In practice, some samples may require this bias correction. When compared to the conventional TIMS method, the total evaporation method is approximately two times faster, improves precision from two to four fold, and utilizes smaller sample sizes. 1.3 The tot...

  16. Effect of precursor concentration on the structural and optical properties of ZnO nanorods prepared by hydrothermal method

    International Nuclear Information System (INIS)

    Lestari, Amie; Iwan, S.; Djuhana, Dede; Imawan, Cuk; Harmoko, Adhi; Fauzia, Vivi

    2016-01-01

    Zinc oxide (ZnO) nanorods has attractive properties for nanoscale optoelectronic applications, such as optical sensors, ultraviolet laser diodes, and photodetectors. ZnO nanorods, can be fabricated by simple and low cost chemical approach, such as hydrothermal method. In this method, the morphology, microstructure, optical and electrical properties of ZnO nanorods are highly determined by process parameters such as solvent, deposition time, deposition temperature as well as annealing condition. In this paper we report the fabrication of ZnO nanorods that were grown on transparent conducting indium tin oxide coated glass substrates. Initially, ZnO seed layers were deposited on heated substrates with temperature of 450 °C using ultrasonic spray pyrolysis method with frequency of 1.7 MHz and then grown by hydrothermal method with three different precursor concentrations, namely 0.02 M, 0.06 M, and 0.1 M. The surface morphology and structure were investigated by field emission scanning electron microscope (FESEM) and x-ray diffraction (XRD), while the optical properties were observed by photoluminescence (PL) and and UV VIS reflectance spectroscopy.

  17. Tangential Flow Ultrafiltration: A “Green” Method for the Size Selection and Concentration of Colloidal Silver Nanoparticles

    Science.gov (United States)

    Anders, Catherine B.; Baker, Joshua D.; Stahler, Adam C.; Williams, Austin J.; Sisco, Jackie N.; Trefry, John C.; Wooley, Dawn P.; Pavel Sizemore, Ioana E.

    2012-01-01

    Nowadays, AgNPs are extensively used in the manufacture of consumer products,1 water disinfectants,2 therapeutics,1, 3 and biomedical devices4 due to their powerful antimicrobial properties.3-6 These nanoparticle applications are strongly influenced by the AgNP size and aggregation state. Many challenges exist in the controlled fabrication7 and size-based isolation4,8 of unfunctionalized, homogenous AgNPs that are free from chemically aggressive capping/stabilizing agents or organic solvents.7-13 Limitations emerge from the toxicity of reagents, high costs or reduced efficiency of the AgNP synthesis or isolation methods (e.g., centrifugation, size-dependent solubility, size-exclusion chromatography, etc.).10,14-18 To overcome this, we recently showed that TFU permits greater control over the size, concentration and aggregation state of Creighton AgNPs (300 ml of 15.3 μg ml-1 down to 10 ml of 198.7 μg ml-1) than conventional methods of isolation such as ultracentrifugation.19 TFU is a recirculation method commonly used for the weight-based isolation of proteins, viruses and cells.20,21 Briefly, the liquid sample is passed through a series of hollow fiber membranes with pore size ranging from 1,000 kD to 10 kD. Smaller suspended or dissolved constituents in the sample will pass through the porous barrier together with the solvent (filtrate), while the larger constituents are retained (retentate). TFU may be considered a "green" method as it neither damages the sample nor requires additional solvent to eliminate toxic excess reagents and byproducts. Furthermore, TFU may be applied to a large variety of nanoparticles as both hydrophobic and hydrophilic filters are available. The two main objectives of this study were: 1) to illustrate the experimental aspects of the TFU approach through an invited video experience and 2) to demonstrate the feasibility of the TFU method for larger volumes of colloidal nanoparticles and smaller volumes of retentate. First

  18. Practical calculation method to estimate the absolute boron concentration in tissues using 18F-FBPA PET.

    Science.gov (United States)

    Watabe, Tadashi; Hanaoka, Kohei; Naka, Sadahiro; Kanai, Yasukazu; Ikeda, Hayato; Aoki, Masanao; Shimosegawa, Eku; Kirihata, Mitsunori; Hatazawa, Jun

    2017-07-01

    The purpose of this study was to establish a practical method to estimate the absolute boron concentrations in the tissues based on the standardized uptake values (SUVs) after administration of 4-borono-phenylalanine (BPA) using 4-borono-2- 18 F-fluoro-phenylalanine ( 18 F-FBPA) PET. Rat xenograft models of C6 glioma (n = 7, body weight 241 ± 28.0 g) were used for the study. PET was performed 60 min after intravenous injection of 18 F-FBPA (30.5 ± 0.7 MBq). After the PET scanning, BPA-fructose (167.3 ± 18.65 mg/kg) was administered by slow intravenous injection to the same subjects. The rats were killed 60 min after the BPA injection and tissue samples were collected from the major organs and tumors. The absolute boron concentrations (unit: ppm) in the samples were measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The boron concentrations in the tissues/tumors were also estimated from the 18 F-FBPA PET images using the following formula: estimated absolute boron concentration (ppm) = 0.0478 × [BPA dose (mg/kg)] × SUV. The measured absolute boron concentrations (mBC) by ICP-OES and the estimated boron concentrations (eBC) from the PET images were compared. The percent difference between the mBC and eBC calculated based on the SUV max was -5.2 ± 21.1% for the blood, -9.4 ± 22.3% for the brain, 1.6 ± 21.3% for the liver, -14.3 ± 16.8% for the spleen, -9.5 ± 27.5% for the pancreas, and 3.4 ± 43.2% for the tumor. Relatively large underestimation was observed for the lung (-48.4 ± 16.2%), small intestine (-37.8 ± 19.3%) and large intestine (-33.9 ± 11.0%), due to the partial volume effect arising from the air or feces contained in these organs. In contrast, relatively large overestimation was observed for the kidney (34.3 ± 29.3%), due to the influence of the high uptake in urine. The absolute boron concentrations in tissues/tumors can be estimated from the SUVs on 18 F-FBPA PET using a

  19. Estimating particulate black carbon concentrations using two offline light absorption methods applied to four types of filter media

    Science.gov (United States)

    Davy, Pamela M.; Tremper, Anja H.; Nicolosi, Eleonora M. G.; Quincey, Paul; Fuller, Gary W.

    2017-03-01

    Atmospheric particulate black carbon has been linked to adverse health outcomes. Additional black carbon measurements would aid a better understanding of population exposure in epidemiological studies as well as the success, or otherwise, of relevant abatement technologies and policies. Two light absorption measurement methods of particles collected on filters have been applied to four different types of filters to provide estimations of particulate black carbon concentrations. The ratio of transmittance (lnI0/I) to reflectance (lnR0/R) varied by filter type and ranged from close to 0.5 (as expected from simple theory) to 1.35 between the four filter types tested. The relationship between light absorption and black carbon, measured by the thermal EC(TOT) method, was nonlinear and differed between filter type and measurement method. This is particularly relevant to epidemiological studies that use light absorption as an exposure metric. An extensive archive of filters was used to derive loading factors and mass extinction coefficients for each filter type. Particulate black carbon time series were then calculated at locations where such measurements were not previously available. When applied to two roads in London, black carbon concentrations were found to have increased between 2011 and 2013, by 0.3 (CI: -0.1, 0.5) and 0.4 (CI: 0.1, 0.9) μg m-3 year-1, in contrast to the expectation from exhaust abatement policies. New opportunities using archived or bespoke filter collections for studies on the health effects of black carbon and the efficacy of abatement strategies are created.

  20. False negative rate and other performance measures of a sponge-wipe surface sampling method for low contaminant concentrations.

    Energy Technology Data Exchange (ETDEWEB)

    Einfeld, Wayne; Krauter, Paula A.; Boucher, Raymond M.; Tezak, Mathew; Amidan, Brett G. (Pacific Northwest National Laboratory, Richland, WA); Piepel, Greg F. (Pacific Northwest National Laboratory, Richland, WA)

    2011-05-01

    Recovery of spores from environmental surfaces is known to vary due to sampling methodology, techniques, spore size and characteristics, surface materials, and environmental conditions. A series of tests were performed to evaluate a new, validated sponge-wipe method. Specific factors evaluated were the effects of contaminant concentrations and surface materials on recovery efficiency (RE), false negative rate (FNR), limit of detection (LOD) - and the uncertainties of these quantities. Ceramic tile and stainless steel had the highest mean RE values (48.9 and 48.1%, respectively). Faux leather, vinyl tile, and painted wood had mean RE values of 30.3, 25.6, and 25.5, respectively, while plastic had the lowest mean RE (9.8%). Results show a roughly linear dependence of surface roughness on RE, where the smoothest surfaces have the highest mean RE values. REs were not influenced by the low spore concentrations tested (3 x 10{sup -3} to 1.86 CFU/cm{sup 2}). The FNR data were consistent with RE data, showing a trend of smoother surfaces resulting in higher REs and lower FNRs. Stainless steel generally had the lowest mean FNR (0.123) and plastic had the highest mean FNR (0.479). The LOD{sub 90} varied with surface material, from 0.015 CFU/cm{sup 2} on stainless steel up to 0.039 on plastic. Selecting sampling locations on the basis of surface roughness and using roughness to interpret spore recovery data can improve sampling. Further, FNR values, calculated as a function of concentration and surface material, can be used pre-sampling to calculate the numbers of samples for statistical sampling plans with desired performance, and post-sampling to calculate the confidence in characterization and clearance decisions.

  1. Experimental measurements of a prototype high-concentration Fresnel lens and sun-tracking method for photovoltaic panel's efficiency enhancement

    Science.gov (United States)

    Rajaee, Meraj; Ghorashi, Seyed Mohamad Bagher

    2015-08-01

    Concentrator photovoltaic modules are a promising technology for highly efficient solar energy conversion. This system presents several advantages due to additional degrees of freedom that has been provided by the spectral separation such as cost and mass reduction, increase in the incident solar flux on PV cells and performances. This paper has proposed a unique photovoltaic solar cell system that consists of semi-Fresnel lens convergent structure and a novel two axis sun tracking module to enhance the efficiency of solar cell by using less cell area and energy losses. The grooves of this lens are calculated according to the refraction and convergent angles of the light easy for perpendicular incidence angle. The update time interval during tracking causes misalignment of the lens' optical axis versus the sunrays. Then an inventive sun-tracking method is introduced to adjust the module so that the incident rays are always perpendicular to the module's surface. As a result, all rays will be refracted with the predetermined angles. This way the focus area is reduced and smaller cells can be used. We also mentioned different module connections in order to provide compensation method during losses, for networks and power systems. Experimental results show that using semi-Fresnel lens, along with the sun-tracking method increases the efficiency of PV panel.

  2. Microparticle content of platelet concentrates is predicted by donor microparticles and is altered by production methods and stress

    DEFF Research Database (Denmark)

    Maurer-Spurej, Elisabeth; Larsen, Rune; Labrie, Audrey

    2016-01-01

    in-vivo and transfer into the final blood component, and how production methods and post-production processing might affect the MPC. We measured MPC using ThromboLUX in (a) platelet-rich plasma (PRP) of 54 apheresis donors and the corresponding apheresis products, (b) 651 apheresis and 646 pooled...... platelet concentrates (PCs) with plasma and 414 apheresis PCs in platelet additive solution (PAS), and (c) apheresis PCs before and after transportation, gamma irradiation, and pathogen inactivation (N = 8, 7, and 12 respectively). ThromboLUX-measured MPC in donor PRP and their corresponding apheresis PC...... samples were highly correlated (r = 0.82, P = .001). The average MPC in pooled PC was slightly lower than that in apheresis PC and substantially lower in apheresis PC stored with PAS rather than plasma. Mirasol Pathogen Reduction treatment significantly increased MPC with age. Thus, MPC measured in donor...

  3. A Simple and Rapid Method for Reducing Radiocesium Concentrations in Wild Mushrooms ( Cantharellus and Boletus ) in the Course of Cooking.

    Science.gov (United States)

    Steinhauser, Georg; Steinhauser, Veronika

    2016-11-01

    Many species of mushrooms are known accumulators of radioactive cesium ( 137 Cs and 134 Cs). Even years and decades after major nuclear accidents, especially those at Chernobyl and Fukushima, mushrooms exhibit high concentrations of these radionuclides. We investigated a simple method for reducing the activity of radiocesium in wild mushrooms (chanterelles, Cantharellus cibarius ; and boleti, Boletus edulis ) during cooking. The juice generated while cooking mushrooms contains a relatively high fraction of the total cesium. The amount of juice can be increased by washing the mushrooms with water prior to cooking. By removing the juice, up to 29% of the radiocesium can be easily removed from chanterelles. Because boleti have a lower affinity for cesium, activity levels were lower in boleti than in chanterelles. The fraction of radiocesium in the juice was lower in boleti than in chanterelles.

  4. Modeling of the Critical Micelle Concentration (CMC) of Nonionic Surfactants with an Extended Group-Contribution Method

    DEFF Research Database (Denmark)

    Mattei, Michele; Kontogeorgis, Georgios; Gani, Rafiqul

    2013-01-01

    A group-contribution (GC) property prediction model for estimating the critical micelle concentration (CMC) of nonionic surfactants in water at 25 °C is presented. The model is based on the Marrero and Gani GC method. A systematic analysis of the model performance against experimental data...... is carried out using data for a wide range of nonionic surfactants covering a wide range of molecular structures. As a result of this procedure, new third order groups based on the characteristic structures of nonionic surfactants are defined and are included in the Marrero and Gani GC model. In this way...... of 150 experimental measurements covering a large variety of nonionic surfactants including linear, branched, and phenyl alkyl ethoxylates; alkanediols; alkyl mono- and disaccharide ethers and esters; ethoxylated alkyl amines and amides; fluorinated linear ethoxylates and amides; polyglycerol esters...

  5. An Isotope Dilution Method for High-frequency Measurements of Dissolved Inorganic Carbon concentration in the Surface Ocean

    Science.gov (United States)

    Huang, K.; Bender, M. L.; Wanninkhof, R. H.; Cassar, N.

    2013-12-01

    Dissolved inorganic carbon (DIC) is one of the most important species in the ocean carbon system. An autonomous system using isotope dilution as its core method has been developed to obtain high-frequency measurements of dissolved inorganic carbon (DIC) concentrations in the surface ocean. This system accurately mixes a seawater sample and a 13C-labeled sodium bicarbonate solution (spike). The mixed solution is then acidified and sent through a gas permeable membrane contactor. CO2 derived from DIC in the mixture is extracted by a CO2-free gas stream, and is sent to a cavity ring-down spectrometer to analyze its 13C/12C ratio. [DIC] of the seawater can then be derived from the measured 13C/12C, the known mixing ratio and the [DI13C] of the spike. The method has been tested under a wide [DIC] range (1800-2800 μmol/kg) in the laboratory. It has also been deployed on a cruise that surveyed ocean waters to the south of Florida. At a sampling resolution of 4 minutes (15 samples per hour), the relative standard deviation of DIC determined from the laboratory tests and the field deployment is ×0.07% and ×0.09%, respectively. The accuracy of the method is better than 0.1% except where [DIC] varies faster than 5 μmol/kg per minute. Based on the laboratory and field evaluations, we conclude that this method can provide accurate underway [DIC] measurements at high resolution in most oceanic regions. Schematic illustration of the work flow.

  6. Performance evaluation of direct saline stool microscopy, Formol ether concentration and Kato Katz diagnostic methods for intestinal parasitosis in the absence of gold standard methods.

    Science.gov (United States)

    Hailu, Tadesse; Abera, Bayeh

    2015-07-01

    The parasite load within the sample and the amount of sample taken during examination greatly compromise the sensitivity of direct saline stool microscopy. A cross-sectional study was conducted in March 2011 in Bahir Dar city among 778 fresh single stool samples to evaluate the performance of direct saline (DS), Kato Katz (KK) and Formol ether concentration (FEC) methods against the 'Gold' standard. Among 778 stool samples from school age children, the highest prevalence of intestinal parasites was recorded by FEC (55.1%). The sensitivity of DS, FEC and KK were 61.1%, 92.3% and 58.7%, respectively. FEC is more sensitive than DS and KK. Hence, use of the latter is preferred. © The Author(s) 2015.

  7. A LC-MS-MS method for determination of low doxazosin concentrations in plasma after oral administration to dogs.

    Science.gov (United States)

    Erceg, Marijana; Cindric, Mario; Pozaic Frketic, Lidija; Vertzoni, Maria; Cetina-Cizmek, Biserka; Reppas, Christos

    2010-02-01

    A rapid and sensitive reversed phase liquid chromatography- tandem mass spectrometry (LC-MS-MS) method is developed for the determination of doxazosin in canine plasma. The samples are prepared by precipitation of proteins using a mixture of methanol and acetonitrile, followed by freezing and evaporation of the organic solvent. The remaining dry residue is redissolved in mobile phase and analyzed by LC-MS-MS with positive electrospray ionization using the selected reactions monitoring mode. An XTerra MS C(18) column, a mobile phase composed of acetonitrile and 2mM ammonium acetate with gradient elution, and a flow rate of 400 microL/min are employed. The elution times for prazosin (internal standard) and doxazosin are approximately 8 and 10 min, respectively. Calibration curves are linear in the 1-20 ng/mL concentration range. Limits of detection and quantification are 0.4 ng/mL and 1.2 ng/mL, respectively. Recovery is higher than 94%. Intra- and inter-day relative standard deviations are below 7% and 8%, respectively. The method is applied for the determination of doxazosin plasma levels following a single administration of doxazosin base and doxazosin mesylate tablets (2 mg dose) to dogs in the fed state. The results indicate possible superiority of the mesylate salt on the plasma input rates of doxazosin.

  8. Zinc injection as a novel castration method in beef bulls: effects on performance, behavior, and testosterone and haptoglobin concentration.

    Science.gov (United States)

    Ball, Jase J; Kegley, Elizabeth B; Lawrence, Ty E; Roberts, Shelby L; Powell, Jeremy G; Richeson, John T

    2018-04-03

    28 d monitoring period. No difference in standing time (P ≥ 0.85) or lying bouts (P = 0.35) occurred. Zinc injection resulted in sterilization but did not cause complete cessation of testicular function evidenced by testosterone concentrations more similar to BUL than BAN. This resulted in overall increased BW and G:F for INJ vs. BAN, yet the acute phase response was markedly greater directly after Zn injection. Collectively, Zn injection resulted in outcomes more similar to BUL than BAN, implying minimal efficacy of INJ as a castration method in older bulls arriving to the feedlot.

  9. Application of bootstrap method for evaluation of the average concentration of Radium-226 in forage palm (Opuntia spp)

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cleomacio Miguel da; Amaral, Romilton dos Santos; Santos Junior, Jose Araujo dos; Vieira, Jose Wilson; Leoterio, Dilmo Marques da Silva [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Radioecologia (RAE)], E-mail: cleomaciomiguel@yahoo.com.br; Amaral, Ademir [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia

    2007-07-01

    The distribution of natural radionuclides in samples from typically anomalous environments has generally a great significant asymmetry, as a result of outlier. For diminishing statistic fluctuation researchers, in radioecology, commonly use geometric mean or median, once the average has no stability under the effect of outliers. As the median is not affected by anomalous values, this parameter of central tendency is the most frequently employed for evaluation of a set of data containing discrepant values. On the other hand, Efron presented a non-parametric method the so-called bootstrap that can be used to decrease the dispersion around the central-tendency value. Generally, in radioecology, statistics procedures are used in order to reduce the effect results of the presence of anomalous values as regards averages. In this context, the present study had as an objective to evaluate the application of the non-parametric bootstrap method (BM) for determining the average concentration of {sup 226}Ra in cultivated forage palms (Opuntia spp.) in soils with uranium anomaly on the dairy milk farms, localized in the cities of Pedra and Venturosa, Pernambuco-Brazil, as well as discussing the utilization of this method in radioecology. The results of {sup 226}Ra in samples of forage palm varied from 1,300 to 25,000 mBq.kg{sup -1} (dry matter), with arithmetic average of 5,965.86 +- 5,903.05 mBq.kg{sup -1}. The result obtained for this average using BM was 5,963.82 +- 1,202.96 mBq.kg{sup -1} (dry matter). The use of BM allowed an automatic filtration of experimental data, without the elimination of outliers, leading to the reduction of dispersion around the average. As a result, the BM permitted reaching a stable arithmetic average of the effects of the outliers. (author)

  10. Development and validation of a high performance liquid chromatography method to determine linezolid concentrations in pig pulmonary tissue.

    Science.gov (United States)

    Guerrero, Laura; Martínez-Olondris, Pilar; Rigol, Montserrat; Esperatti, Mariano; Esquinas, Cristina; Luque, Néstor; Piñer, Raquel; Torres, Antoni; Soy, Dolors

    2010-03-01

    Linezolid is the first synthetic compound of a new group of antimicrobials, the oxazolidinones, which inhibit protein synthesis. It shows a broad spectrum of activity against Gram positive organisms. With respect to its pharmacokinetics, linezolid shows a relatively high volume of distribution and good penetration into inflammatory fluids, bone, fat and muscle. A reversed-phase isocratic high-performance liquid chromatographic method for linezolid analysis in piglet pulmonary tissue is described. Tissue samples and controls were prepared in 1 x TBE (1 M Tris, 0.9 M boric acid, 0.01 M EDTA). The mobile phase consisted of 20% ultrafiltered water and 80% of (A) 15 mM potassium monohydrogen phosphate buffer (pH = 5) with (B) acetonitrile (80%/20%; v/v). Samples were homogenized and precipitated with HClO(4) 3% (1/1, v/v). The injection volume was 100 microL. Ofloxacin was used as an internal standard. The assay was linear over a linezolid concentration range: 1.6-100 microg/mL. The method provided good validation data (n = 15): inaccuracy (3.6%), intra and inter-day variability (4.2% and 5.2%, respectively), recovery (91.8%), limit of detection (0.8 microg/mL) and quantitation (1.6 microg/mL) and acceptable stability within 24 h in the auto-sampler. The method offers a fast and simple approach to determine linezolid in pulmonary tissue which could be of use in pharmacokinetic studies.

  11. Use of passive diffusion sampling method for defining NO2 concentrations gradient in São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Meliefste Kees

    2006-06-01

    Full Text Available Abstract Background Air pollution in São Paulo is constantly being measured by the State of Sao Paulo Environmental Agency, however there is no information on the variation between places with different traffic densities. This study was intended to identify a gradient of exposure to traffic-related air pollution within different areas in São Paulo to provide information for future epidemiological studies. Methods We measured NO2 using Palmes' diffusion tubes in 36 sites on streets chosen to be representative of different road types and traffic densities in São Paulo in two one-week periods (July and August 2000. In each study period, two tubes were installed in each site, and two additional tubes were installed in 10 control sites. Results Average NO2 concentrations were related to traffic density, observed on the spot, to number of vehicles counted, and to traffic density strata defined by the city Traffic Engineering Company (CET. Average NO2concentrations were 63μg/m3 and 49μg/m3 in the first and second periods, respectively. Dividing the sites by the observed traffic density, we found: heavy traffic (n = 17: 64μg/m3 (95% CI: 59μg/m3 – 68μg/m3; local traffic (n = 16: 48μg/m3 (95% CI: 44μg/m3 – 52μg/m3 (p Conclusion The differences in NO2 levels between heavy and local traffic sites are large enough to suggest the use of a more refined classification of exposure in epidemiological studies in the city. Number of vehicles counted, traffic density observed on the spot and traffic density strata defined by the CET might be used as a proxy for traffic exposure in São Paulo when more accurate measurements are not available.

  12. Method development for the enantiomeric purity determination of low concentrations of adrenaline in local anaesthetic solutions by capillary electrophoresis

    NARCIS (Netherlands)

    Sänger-Van De Griend, Cari E.; Ek, Anders G.; Widahl-Näsman, Monica E.; Andersson, E. K Margareta

    2006-01-01

    L-Adrenaline is often included in local anaesthetic (LA) solutions for injection to improve the quality of the anaesthetic block. The concentration of the LA is between 2.5 and 20 mg/ml and the concentration of adrenaline is typically ≤0.1% of the LA concentration. In order to follow the

  13. SIMPLE METHOD FOR ESTIMATING POLYCHLORINATED BIPHENYL CONCENTRATIONS ON SOILS AND SEDIMENTS USING SUBCRITICAL WATER EXTRACTION COUPLED WITH SOLID-PHASE MICROEXTRACTION. (R825368)

    Science.gov (United States)

    A rapid method for estimating polychlorinated biphenyl (PCB) concentrations in contaminated soils and sediments has been developed by coupling static subcritical water extraction with solid-phase microextraction (SPME). Soil, water, and internal standards are placed in a seale...

  14. Catalytic activity of acid and base with different concentration on sol-gel kinetics of silica by ultrasonic method.

    Science.gov (United States)

    Das, R K; Das, M

    2015-09-01

    The effects of both acid (acetic acid) and base (ammonia) catalysts in varying on the sol-gel synthesis of SiO2 nanoparticles using tetra ethyl ortho silicate (TEOS) as a precursor was determined by ultrasonic method. The ultrasonic velocity was received by pulsar receiver. The ultrasonic velocity in the sol and the parameter ΔT (time difference between the original pulse and first back wall echo of the sol) was varied with time of gelation. The graphs of ln[ln1/ΔT] vs ln(t), indicate two region - nonlinear region and a linear region. The time corresponds to the point at which the non-linear region change to linear region is considered as gel time for the respective solutions. Gelation time is found to be dependent on the concentration and types of catalyst and is found from the graphs based on Avrami equation. The rate of condensation is found to be faster for base catalyst. The gelation process was also characterized by viscosity measurement. Normal sol-gel process was also carried out along with the ultrasonic one to compare the effectiveness of ultrasonic. The silica gel was calcined and the powdered sample was characterized with scanning electron microscopy, energy dispersive spectra, X-ray diffractogram, and FTIR spectroscopy. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. A method of estimating multicomponent nonaqueous-phase liquid mass in porous media using aqueous concentration ratios.

    Science.gov (United States)

    Devlint, J F; Barbaro, J R

    2001-11-01

    A simple dissolution model based on Raoult's Law was used to derive a log-linear equation for the estimation of multicomponent nonaqueous-phase liquid (NAPL) mass in porous media. The analysis, referred to here as the ratio mass estimation (RME) method, requires aqueous concentration ratios for two components of the NAPL mixture as well as their pure phase liquid solubilities. Application of the equation using data from a previously reported column experiment, in which 1.22 g of a benzene/toluene NAPL were flushed with water, yielded an estimate of 1.2 g of NAPL. In addition, data from two in situ field column experiments of gasoline dissolution were examined. In those experiments, three ratio pairs, benzene/toluene, ethylbenzene/toluene, and ethylbenzene/benzene, were considered from each cell, and the initial NAPL masses were estimated to be between 39 and 42 kg NAPL, within 30% of the true NAPL masses of 54 kg in each cell. Finally, data from the flushing of a controlled release of chlorinated solvents (chloroform, trichloroethene, and tetrachloroethene) inside a sheet pile cell were examined, and the initial NAPL mass was estimated to within 15% of the true value. The RME analysis is based on several simplifying assumptions and should be used with caution. However, this work shows it to be potentially useful under conditions that might be encountered at sites. The analysis is simple and based on data that are often collected routinely.

  16. Long-Term Precipitation Analysis and Estimation of Precipitation Concentration Index Using Three Support Vector Machine Methods

    Directory of Open Access Journals (Sweden)

    Milan Gocic

    2016-01-01

    Full Text Available The monthly precipitation data from 29 stations in Serbia during the period of 1946–2012 were considered. Precipitation trends were calculated using linear regression method. Three CLINO periods (1961–1990, 1971–2000, and 1981–2010 in three subregions were analysed. The CLINO 1981–2010 period had a significant increasing trend. Spatial pattern of the precipitation concentration index (PCI was presented. For the purpose of PCI prediction, three Support Vector Machine (SVM models, namely, SVM coupled with the discrete wavelet transform (SVM-Wavelet, the firefly algorithm (SVM-FFA, and using the radial basis function (SVM-RBF, were developed and used. The estimation and prediction results of these models were compared with each other using three statistical indicators, that is, root mean square error, coefficient of determination, and coefficient of efficiency. The experimental results showed that an improvement in predictive accuracy and capability of generalization can be achieved by the SVM-Wavelet approach. Moreover, the results indicated the proposed SVM-Wavelet model can adequately predict the PCI.

  17. Research on absolute measurement of 222Rn/220Rn concentrations based on a single small scintillation cell and delay-time method

    International Nuclear Information System (INIS)

    Zhou Jianbo; Zhao Xiuliang; Yu Hong; Xiao Yongjun; Wu Yongyan

    2009-01-01

    A single small scintillation with delay-time method is used to measure radon and thoron concentrations in their mixed atmosphere-of absolute measurement of radon and thoron concentrations was discussed. The conditions of using radon to test this method was described and a experiment was designed to prove it. Compare to the reference number, Its margin of error was -2.9%∼+3.4%, and the best time of the measurement of radon was 10-45 minutes. In conclusion, a single small scintillation cell could be used for absolute measurement radon and thoron concentrations. (authors)

  18. Analysis for trace mercury concentration. I. Critical evaluation of current procedures. II. A proposed method for determination by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Litman, R.

    1975-01-01

    Current methods of sample pretreatments, digestion, lyophilization and extraction, have been found to lead to considerable loss of mercury, at an initial mercury concentration of 1 μg/g, and less. Storage of solutions of mercury at concentrations of less than 1 μg/ml, in glass, Teflon and polyethylene containers, leads to losses by adsorption. Electrochemical reduction of mercury to the metal, and subsequent volatilization, is postulated as the mechanism of loss from the samples studied during lyophilization. A method of instrumental neutron activation analysis, which obviates the above pretreatments, has been developed for mercury concentrations as low as 1 ng/ml

  19. Determination of alcohol and extract concentration in beer samples using a combined method of near-infrared (NIR) spectroscopy and refractometry.

    Science.gov (United States)

    Castritius, Stefan; Kron, Alexander; Schäfer, Thomas; Rädle, Matthias; Harms, Diedrich

    2010-12-22

    A new approach of combination of near-infrared (NIR) spectroscopy and refractometry was developed in this work to determine the concentration of alcohol and real extract in various beer samples. A partial least-squares (PLS) regression, as multivariate calibration method, was used to evaluate the correlation between the data of spectroscopy/refractometry and alcohol/extract concentration. This multivariate combination of spectroscopy and refractometry enhanced the precision in the determination of alcohol, compared to single spectroscopy measurements, due to the effect of high extract concentration on the spectral data, especially of nonalcoholic beer samples. For NIR calibration, two mathematical pretreatments (first-order derivation and linear baseline correction) were applied to eliminate light scattering effects. A sample grouping of the refractometry data was also applied to increase the accuracy of the determined concentration. The root mean squared errors of validation (RMSEV) of the validation process concerning alcohol and extract concentration were 0.23 Mas% (method A), 0.12 Mas% (method B), and 0.19 Mas% (method C) and 0.11 Mas% (method A), 0.11 Mas% (method B), and 0.11 Mas% (method C), respectively.

  20. Illustration of a fingerprinting method to isolate Gold King Release Metals from Background Concentrations in the San Juan River

    Science.gov (United States)

    Detecting the Gold King Mine metals as the release plume passed was difficult once it entered the San Juan River on August 8, 2015. Plume metals concentrations were relatively low after 200 km of travel and deposition in the Animas River while background concentrations of the sa...

  1. [In-situ monitoring algorithm of gases poisonous elements concentration with ultraviolet optical absorption spectroscopy based on recursion iterative method].

    Science.gov (United States)

    Wang, Hui-feng; Jiang, Xu-qian

    2012-01-01

    The key and challenge problem of in-situ monitoring poisonous elements of gases is how to separate the various gases absorption signal from mixed gases absorption spectroscopy and compute it's accuracy concentration? Here we present a new algorithms in return recursion iteration based on Lambert-Beer principle. In the algorithms, recurred by the character of absorption peak of various gases in the band of 190-290 nm UV rays continuous spectroscopy and the character of twin element fold for absorbance are used. Firstly, the authors suppose that there is no absorption for others gases in the character absorption band for a certain gas, the authors can inference the initial concentration of the gas. Then the authors switch to another character spectroscopy, and put the photons that gases absorption out of the total number of absorbed photons that are measured. So we could get the initial concentration of another gas. By analogy the authros can get the initial concentration of all kinds of other poisonous elements. Then come back to the character spectroscopy of the first gas, the authors can get a new concentration of the first gas from the difference between the total number of absorbed photons and the photons that other gases absorption. By analogy the authors can get the iterative concentration of other gases, by irterating this process repeatly for some times until the measurement error of the adjacent gas concentration is smaller than a certain numerical value. Finally the authors can get the real and accurate concentration of all kinds of gases. Experiment shows that the authors can get the accurate concentration of all kinds of gases with the algorithm. The accuracy can be within 2%, and at the same time, it is easy enough to satisfy the necessity of real-time requirement. In addition it could be used to measure the concentration of many kinds of gas at a time. It is robust and suitable to be taken into practice.

  2. Analysis of bioaccessible concentration of trace elements in plant based edible materials by INAA and ICPMS methods

    International Nuclear Information System (INIS)

    Dutta, R.K.; Maharia, R.S.; Acharya, R.; Reddy, A.V.R.

    2014-01-01

    The total metal concentration and bioaccessible concentration of Cr, Mn, Fe, Cu, Zn, Se in Momordica charantia, Asparagus racemosus, Terminalia arjuna and Syzyzium cumini were measured by instrumental neutron activation analysis and by inductively coupled plasma mass spectrometry analysis (ICP-MS). The bioaccessible concentrations were determined in the gastrointestinal digest obtained after treating dried powdered samples sequentially in gastric and intestinal fluid of porcine origin at physiological conditions. The bioaccessible concentration of Fe was in the range of 58-67 mg kg -1 , Mn was 10.2-14.6 mg kg -1 , Cu was 3.7-4.8 mg kg -1 and Zn was 10.6-18.4 mg kg -1 , were within the safety limits set for vegetable food stuff set by Joint FAO/WHO. The bioaccessibility of Zn, an essential element, was high (40-50 %) in M. charantia and in S. cumini. In addition, the total metal contents and bioaccessible concentration of Ni, Se, Cd and Pb in these samples were measured by ICP-MS. The total Cd content in S. cumini (2.6 ± 0.2 mg kg -1 ) and its bioaccessible concentration (0.6 mg kg -1 ) were strikingly high as compared to the other samples. Though total Hg contents were determined by ICP-MS, but their bioaccessible concentrations were below the detection limit (0.036 mg kg -1 ). (author)

  3. Determination of hexavalent chromium concentration in industrial waste incinerator stack gas by using a modified ion chromatography with post-column derivatization method.

    Science.gov (United States)

    Miyake, Yuichi; Tokumura, Masahiro; Iwazaki, Yuta; Wang, Qi; Amagai, Takashi; Horii, Yuichi; Otsuka, Hideyuki; Tanikawa, Noboru; Kobayashi, Takeshi; Oguchi, Masahiro

    2017-06-16

    An ion chromatography with post-column derivatization with 1,5-diphenylcarbazide (IC-DPC) analytical method was modified to enable measurement of trace-level hexavalent chromium (Cr(VI)) in air. One of the difficulties in determining trace levels of Cr(VI) in air with conventional IC-DPC methods is co-elution of the solvent and ion peaks due to high concentrations of ionic compounds in the extract. However, by using gradient elution rather than isocratic elution we were able to fully resolve the Cr(VI) ion peak from the solvent peak without the need for diluting the extract, which would have reduced the minimum quantifiable level of the method. With this method, we were able to detect Cr(VI) in air at concentrations of 5.3ng/m 3 (assuming a sampling volume of 1m 3 and a final solution volume of 10mL). Recovery tests at three different concentrations of Cr(VI) (50, 250, 1000ng) were performed with or without fly ash; recovery rates at all the concentrations of Cr(VI), with or without fly ash, ranged from 68% to 110% (mean±relative standard deviation, 96%±11%), and there were no differences in recovery rates with respect to the presence or absence of fly ash. Finally, we used the developed method to determine the concentration of Cr(VI) in stack gases collected from eight industrial waste incinerators located in Japan. The concentration of Cr(VI) in the stack gases ranged from below the method quantification limit to 3100ng/m 3 . The highest concentrations of Cr(VI) detected in the stack gases were two to three orders of magnitude higher than that in ambient air in Japan. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Errors analysis in the evaluation of particle concentration by PDA on a turbulent two-phase jet: application for cross section and transit time methods

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, Esteban; Garcia, Juan A.; Garcia, Ignacio; Aisa, Luis A. [University of Zaragoza, Area de Mecanica de Fluidos, Centro Politecnico Superior, Zaragoza (Spain)

    2009-09-15

    Phase-Doppler anemometry (PDA) is a powerful tool for two-phase flow measurements and testing. Particle concentration and mass flux can also be evaluated using the raw particle data supplied by this technique. The calculation starts from each particle velocity, diameter, transit time data, and the total measurement time. There are two main evaluation strategies. The first one uses the probe volume effective cross section, and it is usually simplified assuming that particles follow quasi one-directional trajectories. In the text, it will be called the cross section method. The second one includes a set of methods which will be denoted as ''Generalized Integral Methods'' (GIM). Concentration algorithms such as the transit time method (TTM) and the integral volume method (IVM) are particular cases of the GIM. In any case, a previous calibration of the measurement volume geometry is necessary to apply the referred concentration evaluation methods. In this study, concentrations and mass fluxes both evaluated by the cross-section method and the TTM are compared. Experimental data are obtained from a particle-laden jet generated by a convergent nozzle. Errors due to trajectory dispersion, burst splitting, and multi-particle signals are discussed. (orig.)

  5. Physically based method for measuring suspended-sediment concentration and grain size using multi-frequency arrays of acoustic-doppler profilers

    Science.gov (United States)

    Topping, David J.; Wright, Scott A.; Griffiths, Ronald; Dean, David

    2014-01-01

    As the result of a 12-year program of sediment-transport research and field testing on the Colorado River (6 stations in UT and AZ), Yampa River (2 stations in CO), Little Snake River (1 station in CO), Green River (1 station in CO and 2 stations in UT), and Rio Grande (2 stations in TX), we have developed a physically based method for measuring suspended-sediment concentration and grain size at 15-minute intervals using multifrequency arrays of acoustic-Doppler profilers. This multi-frequency method is able to achieve much higher accuracies than single-frequency acoustic methods because it allows removal of the influence of changes in grain size on acoustic backscatter. The method proceeds as follows. (1) Acoustic attenuation at each frequency is related to the concentration of silt and clay with a known grain-size distribution in a river cross section using physical samples and theory. (2) The combination of acoustic backscatter and attenuation at each frequency is uniquely related to the concentration of sand (with a known reference grain-size distribution) and the concentration of silt and clay (with a known reference grain-size distribution) in a river cross section using physical samples and theory. (3) Comparison of the suspended-sand concentrations measured at each frequency using this approach then allows theory-based calculation of the median grain size of the suspended sand and final correction of the suspended-sand concentration to compensate for the influence of changing grain size on backscatter. Although this method of measuring suspended-sediment concentration is somewhat less accurate than using conventional samplers in either the EDI or EWI methods, it is much more accurate than estimating suspended-sediment concentrations using calibrated pump measurements or single-frequency acoustics. Though the EDI and EWI methods provide the most accurate measurements of suspended-sediment concentration, these measurements are labor-intensive, expensive, and

  6. Application of Electro-Oxidation Method for Treatment of Dye Textile Wastewater Using Stainless Steel Electrode: Study of Electrolyte Concentration Effect to Color Removal

    Directory of Open Access Journals (Sweden)

    Jumardin Rua

    2017-09-01

    Full Text Available The increasing number of textile industries has created a new problem of environmental pollution from waste produced. Entering of concentrated wastewater that containing of complex organic compounds to agricultural land and rivers has caused loss to humans or the environment. Treatment of dye textile wastewater by electro-oxidation method using stainless steel electrode has been done. This research consists of several stages: analysis of electrode composition with SEM-EDX, electrolysis of wastewater at variation of electrolyte concentration and analysis of electrolyte concentration effect to color removal percentage of wastewater. The result shows that the electrode composition consisted of iron, chromium, nickel and silica with the main composition of iron in the amount of 72.2%. After electrolysis on variations of electrolyte concentration and analysis of color removal percentage of wastewater, obtained that the largest of color removal percentage on the use of electrolyte concentration of 3% in the amount of 98.81%

  7. An investigation to compare the performance of methods for the determination of free acid in highly concentrated solutions of plutonium and uranium nitrate

    International Nuclear Information System (INIS)

    Crossley, D.

    1980-08-01

    An investigation has been carried out to compare the performance of the direct titration method and the indirect mass balance method, for the determination of free acid in highly concentrated solutions of uranium nitrate and plutonium nitrate. The direct titration of free acid with alkali is carried out in a fluoride medium to avoid interference from the hydrolysis of uranium or plutonium, while free acid concentration by the mass balance method is obtained by calculation from the metal concentration, metal valency state, and total nitrate concentration in a sample. The Gran plot end-point prediction technique has been used extensively in the investigation to gain information concerning the hydrolysis of uranium and plutonium in fluoride media and in other complexing media. The use of the Gran plot technique has improved the detection of the end-point of the free acid titration which gives an improvement in the precision of the determination. The experimental results obtained show that there is good agreement between the two methods for the determination of free acidity, and that the precision of the direct titration method in a fluoride medium using the Gran plot technique to detect the end-point is 0.75% (coefficient of variation), for a typical separation plant plutonium nitrate solution. The performance of alternative complexing agents in the direct titration method has been studied and is discussed. (author)

  8. Validation of analytical method to calculate the concentration of conjugated monoclonal antibody; Validacao de metodo analitico para calculo de concentracao de anticorpo monoclonal conjugado

    Energy Technology Data Exchange (ETDEWEB)

    Alcarde, Lais F.; Massicano, Adriana V.F.; Oliveira, Ricardo S.; Araujo, Elaine B. de, E-mail: lais_alcarde@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The objective of this study was to develop a quantitative analytical method using high performance liquid chromatography (HPLC) to determine the antibody concentration in conjunction with bifunctional chelator. Assays were performed using a high performance liquid chromatograph, and the following conditions were used: flow rate of 1 mL / min, 15 min run time, 0.2 M sodium phosphate buffer pH 7.0 as the mobile phase and column of molecular exclusion BioSep SEC S-3000 (300 x 7.8 mm, 5 μM - Phenomenex). The calibration curve was obtained with AcM diluted in 0.2 M sodium phosphate buffer pH 7.0 by serial dilution, yielding the concentrations: 400 μg/mL, 200 μg/mL, 100 μg/mL, 50 μg/mL, 25 μg/mL and 12.5 μg/mL. From the calibration curve calculated the equation of the line and with it the concentration of the immunoconjugate. To ensure the validity of the method accuracy and precision studies were conducted. The accuracy test consisted in the evaluation of 3 samples of known concentration, being this test performed with low concentrations (50 μg/mL), medium (100 μg/mL) and high (200 μg/mL). The precision test consisted of 3 consecutive measurements of one sample of known concentration, subject to the conditions set forth above for the other tests. The correlation coefficient of the standard curve was greater than 97%, the accuracy was satisfactory at low concentrations as well as accuracy. The method was validated by showing it for the accurate and precise determination of the concentration of the immunoconjugate. Furthermore, this assay was found to be extremely important, because using the correct mass of the protein, the radiochemical purity of the radioimmunoconjugate was above 95% in all studies.

  9. A LC-MS method allowing the analysis of HMX and RDX present at the picogram level in natural aqueous samples without a concentration step.

    Science.gov (United States)

    Vigneau, Olivier; Machuron-Mandard, Xavier

    2009-03-15

    The introduction of chloroform into the nebulising gas of a LC/MS electrospray interface (ESI), in a perfectly controlled way, leads to the formation of intense adducts ([M+Cl](-)) when a mobile phase containing HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane or octogen) and RDX (1,3,5-trintro-1,3,5-triazacyclohexane or hexogen) is eluted. This LC/MS method allows the direct analysis of aqueous samples containing HMX and RDX at the pictogram level without a concentration step. The method is used to determine HMX and RDX concentrations in ground water samples from a military site.

  10. A complexity measure based method for studying the dependance of 222Rn concentration time series on indoor air temperature and humidity.

    Science.gov (United States)

    Mihailovic, D T; Udovičić, V; Krmar, M; Arsenić, I

    2014-02-01

    We have suggested a complexity measure based method for studying the dependence of measured (222)Rn concentration time series on indoor air temperature and humidity. This method is based on the Kolmogorov complexity (KL). We have introduced (i) the sequence of the KL, (ii) the Kolmogorov complexity highest value in the sequence (KLM) and (iii) the KL of the product of time series. The noticed loss of the KLM complexity of (222)Rn concentration time series can be attributed to the indoor air humidity that keeps the radon daughters in air. © 2013 Published by Elsevier Ltd.

  11. Method of determining the variation of concentration of the potential alpha energy of radon daughters with time without changing the filter

    International Nuclear Information System (INIS)

    Feddersen, C.

    1979-01-01

    Considering the drawbacks of sample measurement of radon daughter concentration or potential alpha energy concentration, a method is described allowing to determine the variation with time of the measuring quantities mentioned. For this purpose, the same filter is exposed in defined time intervals and the decay curve is evaluated using Markov's method. Residual activity of preceding measurements is estimated as a function of the density of measuring points. A practicable technique is given for taking into account residual activity together with the background. An apparatus consisting of commercial devices and special accessories of own manufacture is described. The results obtained with this apparatus are illustrated and discussed using two examples. (author)

  12. Research on electrochemical methods for concentration measurement of dissolved ion in molten salt to apply to electrolytic process control. Innovative research adopted in 2002 fiscal year

    International Nuclear Information System (INIS)

    Nagai, Takayuki

    2005-03-01

    The purpose of this research is to establish the online (in-situ) technique for concentration measuring of dissolved ion in the molten salt, and this technique is due to the electrochemical method for the concentration measuring of dissolved ion in solutions like the polarization curve measurement. This research executed the following four items. 1) Examination of possibility for concentration measuring of dissolved ion in molten salt by cyclic voltammetry. 2) Examination of possibility for concentration measuring of dissolved ion in molten salt by various electrochemical methods. 3) Examination of suitable electrochemical method for concentration measuring of dissolved ion. 4) Confirmation of selected electrochemical method for concentration measuring of dissolved ion. It has been understood that the differential pulse voltammetry (DPV) is a promising electrochemical technique for the concentration measuring of dissolved ion in the molten salt as a result of this research. An appropriate measurement condition is as follows, the potential sweep rate is -0.1 V/s, the pulse cycle is 0.1 s, the pulse width is 10 ms, and the pulse voltage is 50 mV. As for the electrodes, the platinum working electrode, the glassy carbon counter electrode, and silver/silver chloride reference electrode are suitable. Moreover, the molar absorptivities of U 3+ , U 4+ , UO 2 + , UO 2 2+ , and the standard redox potentials of couples of U 4+ /U 3+ and UO 2 2+ /UO 2 + were acquired as a basic data of the uranium and the uranyl ion in molten NaCl-2CsCl. (author)

  13. The concentration of trans-lycopene in postharvest watermelon: An evaluation of analytical data obtained by direct methods

    NARCIS (Netherlands)

    Dimitrovski, D.; Bicanic, D.D.; Luterotti, S.; Twisk, van C.; Buijnsters, J.G.; Doka, O.

    2010-01-01

    The performance of the newly proposed laser-based optothermal window (OW) method and colorimetry for quantification of trans -lycopene in 10 watermelon homogenates has been evaluated. Reverse phase HPLC served as an established reference method. Both, OW and colorimetry are direct methods as they,

  14. Mecury in Fin Clips and Scales as Assessment Methods for Predicting Muscle Tissue Mercury Concentrations in Red Drum and Snook

    Science.gov (United States)

    Non-lethal techniques for assessing total mercury concentrations in fish are desired because they minimize impacts on fish populations and allow trends in Hg accumulation to be assessed through repeated sampling of individual fish. This study developed relationships of Hg concent...

  15. [Errors of red cell concentrates recipients: method of analysis using the adverse events notified to the hemovigilance network in 2009].

    Science.gov (United States)

    Falzone, E; Auroy, Y; Hoffmann, C; Sandid, I; Carlier, M; Benhamou, D; Andreu, G; Lienhart, A

    2012-12-01

    Among the adverse events in the blood transfusion process, transfusion to a "wrong" patient is potentially dangerous, as it can lead to an adverse reaction at least in case of ABO incompatible red cell concentrate. The "Root Cause Analysis" working party of the National Hemovigilance Commission developed a tool to collect this type of adverse event, and tested it on a sample of 43 cases involving red cell concentrates notified between March, 2009 and February, 2010. One hundred and nine failures of a step in the transfusion process were observed, i.e. 2.5 failures per adverse event. Failures may occur early in the process. However, they are mainly found at the time of issuing of the blood component, and further, in the clinical ward. How the failure is eventually detected is not always described when the blood component has been fully transfused, in contrast with the cases where actual transfusion to the wrong patient has been prevented. Knowing the way of failure detection enables an objective approach of the efficacy of the numerous existing safety measures. In this sample, bedside controls (documents check as well as the use of anti-A and anti-B reagents with patient's blood and red cell concentrates) detected the failure in three cases out of 34, which were not detected before, showing an efficacy similar to the administrative control done at reception in the clinical ward. The document, set up to analyse step by step these cases of patient errors, will be used in the future to analyse all similar cases, not only with red cell concentrates, but also with platelet concentrates and fresh frozen plasma, ultimately in order to improve their prevention. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  16. Application Study of Comprehensive Forecasting Model Based on Entropy Weighting Method on Trend of PM2.5 Concentration in Guangzhou, China

    Science.gov (United States)

    Liu, Dong-jun; Li, Li

    2015-01-01

    For the issue of haze-fog, PM2.5 is the main influence factor of haze-fog pollution in China. The trend of PM2.5 concentration was analyzed from a qualitative point of view based on mathematical models and simulation in this study. The comprehensive forecasting model (CFM) was developed based on the combination forecasting ideas. Autoregressive Integrated Moving Average Model (ARIMA), Artificial Neural Networks (ANNs) model and Exponential Smoothing Method (ESM) were used to predict the time series data of PM2.5 concentration. The results of the comprehensive forecasting model were obtained by combining the results of three methods based on the weights from the Entropy Weighting Method. The trend of PM2.5 concentration in Guangzhou China was quantitatively forecasted based on the comprehensive forecasting model. The results were compared with those of three single models, and PM2.5 concentration values in the next ten days were predicted. The comprehensive forecasting model balanced the deviation of each single prediction method, and had better applicability. It broadens a new prediction method for the air quality forecasting field. PMID:26110332

  17. Time-course study and effects of drying method on concentrations of gamma-aminobutyric acid, flavonoids, anthocyanin, and 2''-hydroxynicotianamine in leaves of buckwheats.

    Science.gov (United States)

    Suzuki, Tatsuro; Watanabe, Masami; Iki, Makiko; Aoyagi, Yasuo; Kim, Sun-Ju; Mukasa, Yuji; Yokota, Satoshi; Takigawa, Shigenobu; Hashimoto, Naoto; Noda, Takahiro; Yamauchi, Hiroaki; Matsuura-Endo, Chie

    2009-01-14

    Concentrations of gamma-aminobutyric acid (GABA), rutin, minor flavonoids (such as orientin), anthocyanin, and 2''-hydroxynicotianamine (2HN) were quantified in the leaves of common and tartary buckwheat (Fagopyrum esculentum Moench and Fagopyrum tataricum Gaertn., respectively), at 14, 28, and 42 days after sowing (DAS). GABA and rutin concentrations peaked at 42 DAS, whereas anthocyain, 2HN, and minor flavonoid concentrations declined with the age of the plants. However, at 42 DAS, anthocyanin concentrations in the leaves of tartary buckwheat Hokkai T10 leaves were at least 10-fold greater than in the other buckwheats tested. In addition, the effects on target compound concentrations and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity of three different drying methods (20 h at 40 degrees C, 7 h at 70 degrees C, or lyophilization) were investigated. In general, the drying method had no significant effect on the parameters tested. These results indicate that, in terms of GABA, rutin, and anthocyanin concentrations, leaf powder from 42 day old Hokkai T10 has the potential to be a useful food ingredient, such as Ao-jiru juice.

  18. Evaluation of the concentrations of rare earth elements, uranium and thorium in the soil-plant system by Neutron Activation, k0 method

    International Nuclear Information System (INIS)

    Moura, Rodrigo Reis de; Menezes, Maria Ângela de Barros Correia; Marques, Douglas José

    2017-01-01

    The nuclear technique Neutron Activation Analysis (NAA) has improved results in a wide range of research fields, since it is a sensitive technique to determine very low concentrations at the trace level in several matrices.The k0 standardized is a NAA method that has been outstanding in the last decades because there is not the inconvenience of using standards for the elements of interest in the analysis. This increases the accuracy of the method and decreases the uncertainties in the obtained results. In this assessment, the NAA was applied to determine the rare earth elements (REEs), U and Th concentrations in plant and soil samples from a mining area. The data obtained by k0-method were used to calculate the amount of the concentrations of these elements present in the sample soil that were uptaken and fractionated in the studied plants by parameters commonly used, the Transfer Factor (TF) and Bio-concentration Coefficient (BC). The results showed that TF was slightly enriched to REEs (mainly La and Nd) and U and depleted to Th. The results presented to BC confirmed that among plant organs the root accumulated higher REEs concentration levels (root > stem > leaf) and on leaves were not detected Sm (Baccharis crispa), Eu (Baccharis crispa and Tibouchina granulosa) and Yb (Pteridium arachnoideum). Among species studied, Pteridium arachnoideum (fern) was the one that most uptaken and accumulated REEs, U and Th. (author)

  19. Evaluation of the concentrations of rare earth elements, uranium and thorium in the soil-plant system by Neutron Activation, k{sub 0} method

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Rodrigo Reis de, E-mail: rodrigoreismoura@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pós-Graduação em Ciências e Técnicas Nucleares; Menezes, Maria Ângela de Barros Correia, E-mail: menezes@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (SERTA/CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Serviço de Técnicas Analíticas; Marques, Douglas José, E-mail: douglasjmarques81@yahoo.com.br [Universidade José do Rosário Vellano (Unifenas), Alfenas, MG (Brazil). Setor de Olericultura e Experimentação em Agricultura Orgânica

    2017-07-01

    The nuclear technique Neutron Activation Analysis (NAA) has improved results in a wide range of research fields, since it is a sensitive technique to determine very low concentrations at the trace level in several matrices.The k0 standardized is a NAA method that has been outstanding in the last decades because there is not the inconvenience of using standards for the elements of interest in the analysis. This increases the accuracy of the method and decreases the uncertainties in the obtained results. In this assessment, the NAA was applied to determine the rare earth elements (REEs), U and Th concentrations in plant and soil samples from a mining area. The data obtained by k0-method were used to calculate the amount of the concentrations of these elements present in the sample soil that were uptaken and fractionated in the studied plants by parameters commonly used, the Transfer Factor (TF) and Bio-concentration Coefficient (BC). The results showed that TF was slightly enriched to REEs (mainly La and Nd) and U and depleted to Th. The results presented to BC confirmed that among plant organs the root accumulated higher REEs concentration levels (root > stem > leaf) and on leaves were not detected Sm (Baccharis crispa), Eu (Baccharis crispa and Tibouchina granulosa) and Yb (Pteridium arachnoideum). Among species studied, Pteridium arachnoideum (fern) was the one that most uptaken and accumulated REEs, U and Th. (author)

  20. Determination of Tb, Dy, Ho, Er and Yb in ores and concentrates by ICP-OES method

    International Nuclear Information System (INIS)

    Kanicky, V.; Toman, J.; Malecek, M.

    1988-01-01

    Optical emission spectroscopy was used (OES) to analyse apatite from the Kola peninsula with a total content of 0.9% oxides of heavy rare earth elements, the hydroxide concentrate of apatite, the oxide concentrate of rare earth elements, bastnaesite minerals and raw materials containing monasite. Measurements were made with a PV 8210/8280 spectrometer (width of spectral interval in the 1st order of the spectrum 0.028 mm) and an ICP PV 8490 generator. The spectra were measured of 19 most sensitive analytical lines of heavy rare earth elements (8 Tb, 3 Dy, 1 Ho, 3 Er, 4 Yb). The mutual interferences of the different elements, detection limits and resolution limits were determined. The results of the determination of rare earth elements and of certain general elements in the analysed raw materials are tabulated. (E.S.). 2 figs., 11 tabs., 10 refs

  1. A high precision mass spectrometry method for measuring O2/N2 ratios and CO2 concentrations in air

    International Nuclear Information System (INIS)

    Marca, A.D.; Dennis, P.F.; Etchells, A.

    2002-01-01

    A full, detailed understanding of the global carbon budget is needed for robust modelling of global climate and environmental change. Since the industrial revolution the carbon cycle has been shifted from a steady state in which removal of CO 2 from the atmosphere through photosynthesis is balanced by its addition through respiration. Currently increased respiration due to deforestation, modern agricultural practises and the burning of fossil fuels dominates photosynthesis resulting in modern atmospheric CO 2 concentrations some 32% higher than the year 1800 levels. However, the CO 2 concentration rises are lower than expected from known fossil fuel combustion inventories. A significant proportion of the excess CO 2 is taken up by the oceans, however a missing carbon sink must still be invoked to account for the difference between measured and expected CO 2 rises. A global greening as a result of increased photosynthesis is required to close the circle

  2. Modeling of the Critical Micelle Concentration (CMC) of Nonionic Surfactants with an Extended Group-Contribution Method

    DEFF Research Database (Denmark)

    Mattei, Michele; Kontogeorgis, Georgios; Gani, Rafiqul

    2013-01-01

    of 150 experimental measurements covering a large variety of nonionic surfactants including linear, branched, and phenyl alkyl ethoxylates; alkanediols; alkyl mono- and disaccharide ethers and esters; ethoxylated alkyl amines and amides; fluorinated linear ethoxylates and amides; polyglycerol esters...... concentration, and in particular, the quantitative structure−property relationship models, the developed GC model provides an accurate correlation and allows for an easier and faster application in computer-aided molecular design techniques facilitating chemical process and product design....

  3. Nighttime residential wood burning evidenced from an indirect method for estimating real-time concentration of particulate organic matter (POM)

    International Nuclear Information System (INIS)

    Sciare, J.; Sarda-Esteve, R.; Favez, O.; Cachier, H.; Aymoz, G.; Laj, P.

    2008-01-01

    Real-time analyzers of selected chemical components (sulfate, nitrate, Black Carbon) and integrative aerosol parameters (particulate matter and light scattering coefficient) were implemented for a 2-week campaign (November-December 2005) in a suburban area of Clermont-Ferrand (France) in order to document fast changes in the chemical composition of submicron aerosols. Measurements of particulate organic matter (POM) were not available in the field but were indirectly estimated from time-resolved (3-min) reconstruction of the light scattering coefficient. This methodology offered the opportunity to investigate almost real-time and artifact-free POM concentrations even at low concentrations (typically below 0.1 mu g m(-3)). The overall uncertainties associated with this POM calculation were of the order of 20%, which are comparable to those commonly referred in literature for POM calculation or measurements. A chemical mass balance (CMB) of PM1 was performed using the derived POM concentrations and showed a very good correlation (slope = 0.93; r(2) = 0.91, N = 663) with real-time PM1 measurements obtained from R and P TEOM-FDMS, demonstrating the consistency of our approach. Important diurnal variations were observed in POM concentrations, with a dominant contribution of POM from fossil fuel origin during daytime and a dominant contribution of POM from residential wood burning at night. POM was calculated to contribute as much as 70% of PM1 during our study, pointing out the major role of carbonaceous aerosols at this period of the year at our residential area. (authors)

  4. Effect of variable cerium concentration on photoluminescence behaviour in ZrO{sub 2} phosphor synthesized by combustion synthesis method

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, Vikas, E-mail: jsvikasdubey@gmail.com [Department of Physics, Bhilai Institute of Technology, Raipur, 493661 (India); Kaur, Jagjeet [Department of Physics, Govt. V.Y.T. PG. Auto. College, Durg (India)

    2016-05-06

    Present paper reports synthesis and characterization of trivalent cerium (Ce{sup 3+}) doped zirconium dioxide (ZrO{sub 2}) phosphors. Effect of variable concentration of cerium on photoluminescence (PL) is studied. Samples were prepared by combustion synthesis technique which is suitable for less time taking techniques also for large scale production for phosphors. Starting material used for sample preparation are Zr(NO{sub 3}){sub 3} and Ce(NO{sub 3}){sub 3} and urea used as a fuel. All prepared phosphor with variable concentration of Ce{sup 3+} (0.1 to 2mol%) was studied by photoluminescence analysis it is found that the excitation spectra of prepared phosphor shows broad excitation centred at 390nm. The excitation spectra with variable concentration of Ce{sup 3+} show strong peaks at 447nm. Spectrophotometric determinations of peaks are evaluated by Commission Internationale de I’Eclairage technique. Using this phosphor, the desired CIE values including emissions throughout the violet (390 nm) and blue (427 nm) of the spectra were achieved. Efficient blue light emitting diodes were fabricated using Ce{sup 3+} doped phosphor based on near ultraviolet (NUV) excited LED lights.

  5. A SYSTEM AND A METHOD FOR PREDICTION OF NOx EMISSION AND/OR FREE LIME CONCENTRATION IN A CEMENT KILN

    DEFF Research Database (Denmark)

    2008-01-01

    The invention relates to a method (and corresponding soft sensor) for determining one or more cement kiln process parameters, the method comprising the steps of collecting at least one process measurement representing at least one process parameter and collecting at least one item of image data r...

  6. Standard Test Method for Calibration of Primary Non-Concentrator Terrestrial Photovoltaic Reference Cells Using a Tabular Spectrum

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method is intended to be used for calibration and characterization of primary terrestrial photovoltaic reference cells to a desired reference spectral irradiance distribution, such as Tables G173. The recommended physical requirements for these reference cells are described in Specification E1040. Reference cells are principally used in the determination of the electrical performance of photovoltaic devices. 1.2 Primary photovoltaic reference cells are calibrated in natural sunlight using the relative spectral response of the cell, the relative spectral distribution of the sunlight, and a tabulated reference spectral irradiance distribution. 1.3 This test method requires the use of a pyrheliometer that is calibrated according to Test Method E816, which requires the use of a pyrheliometer that is traceable to the World Radiometric Reference (WRR). Therefore, reference cells calibrated according to this test method are traceable to the WRR. 1.4 This test method is a technique that may be used ...

  7. Water quality - Determination of the activity concentration of radionuclides - Method by high resolution gamma-ray spectrometry. 2. ed.

    International Nuclear Information System (INIS)

    2007-01-01

    This International Standard allows (after proper sampling, sample handling and, when necessary or desirable, sample preparation) the simultaneous determination of the activity concentration of several gamma-ray emitting radionuclides in water samples by gamma-ray spectrometry using high purity germanium [HPGe] detectors. Gamma-ray emitting radionuclides are widespread both as naturally occurring and as man-made radionuclides. Therefore, environmental samples usually contain a multitude of different gamma-ray emitters and high resolution gamma-ray spectrometry provides a useful analytical tool for environmental measurements. Gamma rays cause electron-hole pairs when interacting with matter. When a voltage is applied across a semiconductor detector, these electron hole-pairs are, after proper amplification, detected as current pulses. The pulse height is related to the energy absorbed from the gamma-photon or photons in the resolving time of the detector and electronics. By discriminating between the height of the pulses, a gamma-ray pulse height spectrum is obtained. After analysis of the spectrum, the various peaks are assigned to the radionuclides which emitted the corresponding gamma rays using the previously obtained energy detector calibration. The concentration of the radionuclides present in the sample is calculated using the previously obtained energy dependent detector efficiency. The paper provides information on scope, normative references, terms and conditions, symbols and units, principle, reference sources, reagents, gamma spectrometry equipment, sampling, procedure, expression of results and test report followed by Annex A (Example of a carrier solution which can be added to the water sample when waste water from a nuclear power plant is investigated), Annex B (Calculation of the activity concentration from a gamma spectrum using a linear background subtraction (undisturbed peak) and a bibliography

  8. Method and apparatus for measuring the concentration of water, iron, and aluminum in iron ore by neutron radiation

    International Nuclear Information System (INIS)

    Holmes, R.J.; Wylie, A.W.; McCracken, K.G.

    1975-01-01

    Techniques and apparatus for measuring the concentration of water and specific components in materials are described. The techniques involve irradiating the material with neutrons and monitoring the neutron flux in the vicinity of the irradiated material and the gamma radiation from excited nuclei of the specific component. Examples of the use of the invention include on-stream monitoring of ores carried by conveyor belts and borehole logging using a probe which carries a neutron source, and neutron and gamma radiation detectors. (U.S.)

  9. Method of gentle extraction and subsequent concentration at low temperature of natural compounds in the extract from plants

    DEFF Research Database (Denmark)

    Norddahl, Birgir; Christensen, Knud Villy

    2007-01-01

    not soluble in the previous liquid and thus enabling optimal extractions of all compounds. Practically all known extracting liquids can be used by this equipment. Extracts from the extraction operation can subsequently be concentrated using a membrane distillation unit operating with hydrophobic microporous...... membranes for polar solvents and pervaporation membranes for unpolar solutes, where solutes with a low vapour pressure are retained, while components with higher vapour pressures permeate the membrane including water and most other solvents. The operation is performed at relatively low temperature enabling...

  10. Spectral filtering modulation method for estimation of hemoglobin concentration and oxygenation based on a single fluorescence emission spectrum in tissue phantoms.

    Science.gov (United States)

    Liu, Quan; Vo-Dinh, Tuan

    2009-10-01

    Hemoglobin concentration and oxygenation in tissue are important biomarkers that are useful in both research and clinical diagnostics of a wide variety of diseases such as cancer. The authors aim to develop simple ratiometric method based on the spectral filtering modulation (SFM) of fluorescence spectra to estimate the total hemoglobin concentration and oxygenation in tissue using only a single fluorescence emission spectrum, which will eliminate the need of diffuse reflectance measurements and prolonged data processing as required by most current methods, thus enabling rapid clinical measurements. The proposed method consists of two steps. In the first step, the total hemoglobin concentration is determined by comparing a ratio of fluorescence intensities at two emission wavelengths to a calibration curve. The second step is to estimate oxygen saturation by comparing a double ratio that involves three emission wavelengths to another calibration curve that is a function of oxygen saturation for known total hemoglobin concentration. Theoretical derivation shows that the ratio in the first step is linearly proportional to the total hemoglobin concentrations and the double ratio in the second step is related to both total hemoglobin concentration and hemoglobin oxygenation for the chosen fiber-optic probe geometry. Experiments on synthetic fluorescent tissue phantoms, which included hemoglobin with both constant and varying oxygenation as the absorber, polystyrene spheres as scatterers, and flavin adenine dinucleotide as the fluorophore, were carried out to validate the theoretical prediction. Tissue phantom experiments confirm that the ratio in the first step is linearly proportional to the total hemoglobin concentration and the double ratio in the second step is related to both total hemoglobin concentrations and hemoglobin oxygenation. Furthermore, the relations between the two ratios and the total hemoglobin concentration and hemoglobin oxygenation are insensitive

  11. Determination of endogenous concentrations of nitrites and nitrates in different types of cheese in the United States: method development and validation using ion chromatography.

    Science.gov (United States)

    Genualdi, Susan; Jeong, Nahyun; DeJager, Lowri

    2018-04-01

    Nitrites and nitrates can be present in dairy products from both endogenous and exogenous sources. In the European Union (EU), 150 mg kg - 1 of nitrates are allowed to be added to the cheese milk during the manufacturing process. The CODEX General Standard for Food Additives has a maximum permitted level of 50 mg kg - 1 residue in cheese, while in the United States (U.S.) nitrates are unapproved for use as food additives in cheese. In order to be able to investigate imported cheeses for nitrates intentionally added as preservatives and the endogenous concentrations of nitrates and nitrites present in cheeses in the U.S. marketplace, a method was developed and validated using ion chromatography with conductivity detection. A market sampling of cheese samples purchased in the Washington DC metro area was performed. In 64 samples of cheese, concentrations ranged from below the method detection limit (MDL) to 26 mg kg - 1 for nitrates and no concentrations of nitrites were found in any of the cheese samples above the MDL of 0.1 mg kg - 1 . A majority of the samples (93%) had concentrations below 10 mg kg - 1 , which indicate the presence of endogenous nitrates. The samples with concentrations above 10 mg kg - 1 were mainly processed cheese spread, which can contain additional ingredients often of plant-based origin. These ingredients are likely the cause of the elevated nitrate concentrations. The analysis of 12 additional cheese samples that are liable to the intentional addition of nitrates, 9 of which were imported, indicated that in this limited study, concentrations of nitrate in the U.S.-produced cheeses did not differ from those in imported samples.

  12. Impact of urine concentration adjustment method on associations between urine metals and estimated glomerular filtration rates (eGFR) in adolescents

    International Nuclear Information System (INIS)

    Weaver, Virginia M.; Vargas, Gonzalo García; Silbergeld, Ellen K.; Rothenberg, Stephen J.; Fadrowski, Jeffrey J.; Rubio-Andrade, Marisela; Parsons, Patrick J.; Steuerwald, Amy J.

    2014-01-01

    Positive associations between urine toxicant levels and measures of glomerular filtration rate (GFR) have been reported recently in a range of populations. The explanation for these associations, in a direction opposite that of traditional nephrotoxicity, is uncertain. Variation in associations by urine concentration adjustment approach has also been observed. Associations of urine cadmium, thallium and uranium in models of serum creatinine- and cystatin-C-based estimated GFR (eGFR) were examined using multiple linear regression in a cross-sectional study of adolescents residing near a lead smelter complex. Urine concentration adjustment approaches compared included urine creatinine, urine osmolality and no adjustment. Median age, blood lead and urine cadmium, thallium and uranium were 13.9 years, 4.0 μg/dL, 0.22, 0.27 and 0.04 g/g creatinine, respectively, in 512 adolescents. Urine cadmium and thallium were positively associated with serum creatinine-based eGFR only when urine creatinine was used to adjust for urine concentration (β coefficient=3.1 mL/min/1.73 m 2 ; 95% confidence interval=1.4, 4.8 per each doubling of urine cadmium). Weaker positive associations, also only with urine creatinine adjustment, were observed between these metals and serum cystatin-C-based eGFR and between urine uranium and serum creatinine-based eGFR. Additional research using non-creatinine-based methods of adjustment for urine concentration is necessary. - Highlights: • Positive associations between urine metals and creatinine-based eGFR are unexpected. • Optimal approach to urine concentration adjustment for urine biomarkers uncertain. • We compared urine concentration adjustment methods. • Positive associations observed only with urine creatinine adjustment. • Additional research using non-creatinine-based methods of adjustment needed

  13. Impact of urine concentration adjustment method on associations between urine metals and estimated glomerular filtration rates (eGFR) in adolescents

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Virginia M., E-mail: vweaver@jhsph.edu [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD (United States); Johns Hopkins University School of Medicine, Baltimore, MD (United States); Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD (United States); Vargas, Gonzalo García [Faculty of Medicine, University of Juárez of Durango State, Durango (Mexico); Secretaría de Salud del Estado de Coahuila, Coahuila, México (Mexico); Silbergeld, Ellen K. [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD (United States); Rothenberg, Stephen J. [Instituto Nacional de Salud Publica, Centro de Investigacion en Salud Poblacional, Cuernavaca, Morelos (Mexico); Fadrowski, Jeffrey J. [Johns Hopkins University School of Medicine, Baltimore, MD (United States); Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD (United States); Rubio-Andrade, Marisela [Faculty of Medicine, University of Juárez of Durango State, Durango (Mexico); Parsons, Patrick J. [Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, Albany, NY (United States); Department of Environmental Health Sciences, School of Public Health, University at Albany, Albany, NY (United States); Steuerwald, Amy J. [Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, Albany, NY (United States); and others

    2014-07-15

    Positive associations between urine toxicant levels and measures of glomerular filtration rate (GFR) have been reported recently in a range of populations. The explanation for these associations, in a direction opposite that of traditional nephrotoxicity, is uncertain. Variation in associations by urine concentration adjustment approach has also been observed. Associations of urine cadmium, thallium and uranium in models of serum creatinine- and cystatin-C-based estimated GFR (eGFR) were examined using multiple linear regression in a cross-sectional study of adolescents residing near a lead smelter complex. Urine concentration adjustment approaches compared included urine creatinine, urine osmolality and no adjustment. Median age, blood lead and urine cadmium, thallium and uranium were 13.9 years, 4.0 μg/dL, 0.22, 0.27 and 0.04 g/g creatinine, respectively, in 512 adolescents. Urine cadmium and thallium were positively associated with serum creatinine-based eGFR only when urine creatinine was used to adjust for urine concentration (β coefficient=3.1 mL/min/1.73 m{sup 2}; 95% confidence interval=1.4, 4.8 per each doubling of urine cadmium). Weaker positive associations, also only with urine creatinine adjustment, were observed between these metals and serum cystatin-C-based eGFR and between urine uranium and serum creatinine-based eGFR. Additional research using non-creatinine-based methods of adjustment for urine concentration is necessary. - Highlights: • Positive associations between urine metals and creatinine-based eGFR are unexpected. • Optimal approach to urine concentration adjustment for urine biomarkers uncertain. • We compared urine concentration adjustment methods. • Positive associations observed only with urine creatinine adjustment. • Additional research using non-creatinine-based methods of adjustment needed.

  14. Capillary gas chromatographic detection of invert sugar in heated, adulterated, and adulterated and heated apple juice concentrates employing the equilibrium method.

    Science.gov (United States)

    Low, N H; McLaughlin, M; Hofsommer, H J; Hammond, D A

    1999-10-01

    The equilibrium method is introduced for the detection of invert sugar addition to apple juice. The method consists of a pre-equilibration of the sample with dry pyridine at 50 degrees C for 20 min followed by the addition of trimethylsilylimidazole and heating at 75 degrees C for 40 min. The resulting derivatized carbohydrates are then analyzed by capillary gas chromatography. This method was successfully used by independent laboratories to distinguish heated pure, intentionally adulterated (with invert sugar), and intentionally adulterated and then heated apple juice concentrates. The equilibrium method was shown to give significantly lower coefficients of variation for this sample set when compared to the original capillary gas chromatographic method. In addition, these results indicate that it may also be an effective method for the detection of medium invert sugar, depending on the level of the fingerprint oligosaccharides in this sweetener.

  15. Optimal Concentration of Organic Solvents to be Used in the Broth Microdilution Method to Determine the Antimicrobial Activity of Natural Products Against Paenibacillus Larvae

    Directory of Open Access Journals (Sweden)

    Cugnata Noelia Melina

    2017-06-01

    Full Text Available American Foulbrood (AFB is a bacterial disease, caused by Paenibacillus larvae, that affects honeybees (Apis mellifera. Alternative strategies to control AFB are based on the treatment of the beehives with antimicrobial natural substances such as extracts, essential oils and/or pure compounds from plants, honey by-products, bacteria and moulds. The broth microdilution method is currently one of the most widely used methods to determine the minimum inhibitory concentration (MIC of a substance. In this regard, the fact that most natural products, due to their lipophilic nature, must be dissolved in organic solvents or their aqueous mixtures is an issue of major concern because the organic solvent becomes part of the dilution in the incubation medium, and therefore, can interfere with bacterial viability depending on its nature and concentration. A systematic study was carried out to determine by the broth microdilution method the MIC and the maximum non inhibitory concentration (MNIC against P. larvae of the most common organic solvents used to extract or dissolve natural products, i.e. ethanol, methanol, acetonitrile, n-butanol, dimethylsulfoxide, and acidified hydromethanolic solutions. From the MIC and MNIC for each organic solvent, recommended maximum concentrations in contact with P. larvae were established: DMSO 5% (v/v, acetonitrile 7.5% (v/v, ethanol 7.5% (v/v, methanol 12% (v/v, n-butanol 1% (v/v, and methanol-water-acetic acid (1.25:98.71:0.04, v/v/v.

  16. Effects of three seeding methods on optimization of temperature, concentration and reaction time on optical properties during growth ZnO nanorods

    Science.gov (United States)

    Taheri Ghahrizjani, Reza; Yousefi, Mohammad Hassan

    2017-12-01

    Today, use of zinc oxide nanorods is necessary in optoelectronic industry. Therefore, control of growth parameters are affected on zinc oxide nanostructures. In this paper, the effect of different seed methods such as spin coating, vapour liquid solid and spray coating on morphology of surface-crystal plates of zinc oxide nanorods has been investigated. Also, growth of zinc oxide nanorods has been done using new method by use of different concentrations of zinc chloride and ammonia at75, 97 and 110 °C. Finally, morphology of surface, crystal plates, structure purity and optical properties of zinc oxide nano rods have been examined by changes of reagent concentration, growth solution temperature and reaction time through SEM, XRD, EDAX and photoluminescence analyses. The different optical properties and surface morphology of zinc oxide nanorods were generated differ by change in concentration. By changes of concentration, pH of growth solution has been changed. Therefor influences defects of crystal structure in the visible and ultraviolet region were obtained. Finally, the ideal thermal annealing is 430 °C. Thermal annealing in vacuum for growth the zinc oxide nano rods at the range of 400-450 °C were showed that, the defects are decreased and or increased due this method for growth in the visible and ultraviolet region. The samples prepared by VLS, have visible and ultraviolet region emission. So there are useful for LED application. It is suitable for UV-laser diodes.

  17. Dilution Methods in Flow Injection Analysis. Evaluation of Different Approaches as Exemplified for the Determination of Nitrosyl in Concentrated Sulphuric Acid

    DEFF Research Database (Denmark)

    Jørgensen, Ulla Vang; Nielsen, Steffen; Hansen, Elo Harald

    1998-01-01

    in conjunction with knotted reactors of relatively large internal diameter (1.5 mm). The optimized FI-manifold was used with the Griess method for the spectrophotometric assay of nitrosyl (nitrite) in standards prepared in the matrix of concentrated sulphuric acid (detection limit 0.16 mg/l NO+-N (3s......Instigated by developing a flow injection procedure for assay of nitrosyl in concentrated sulphuric acid, different approaches for reliable and robust on-line dilution in FIA were evaluated. These comprised the application of mixing tees in conjunction with mixing coils (including knotted reactors...

  18. Relationship of Temperature and NO{sub x} Concentration during Primary Method on Reduction using in Flame of Natural Gas

    Energy Technology Data Exchange (ETDEWEB)

    Poskart, Monika; Szecowka, Lech [Technical Univ. of Czestochowa (Poland). Dept. of Industrial Furnaces and Environmental Protection

    2006-01-15

    Nitrogen oxides are some of the most harmful components polluting the atmosphere. Energetic criteria require establishing the complex technological parameters (capacity, temperature, pressure, composition of products, lost of heat and others) with the possibility of the highest energy efficiency. Ecological criteria lead to minimization of harmful substations emission. However, it is possible to limit the negative influence of hazardous components on natural environment. So-called 'primary methods', which relied on the modification of combustion process, are the most effective and cheapest methods of pollution limitation. This paper included the results of NO{sub x} reduction in combustion process with application of primary methods such as: flue gas recirculation, air and fuel staging.

  19. Enhancement of Methane Concentration by Removing Contaminants from Biogas Mixtures Using Combined Method of Absorption and Adsorption

    Directory of Open Access Journals (Sweden)

    Muhammad Rashed Al Mamun

    2017-01-01

    Full Text Available We report a laboratory scale combined absorption and adsorption chemical process to remove contaminants from anaerobically produced biogas using cafeteria (food, vegetable, fruit, and cattle manure wastes. Iron oxide (Fe2O3, zero valent iron (Feo, and iron chloride (FeCl2 react with hydrogen sulfide (H2S to deposit colloidal sulfur. Silica gel, sodium sulfate (Na2SO4, and calcium oxide (CaO reduce the water vapour (H2O and carbon dioxide (CO2. It is possible to upgrade methane (CH4 above 95% in biogas using chemical or physical absorption or adsorption process. The removal efficiency of CO2, H2S, and H2O depends on the mass of removing agent and system pH. The results showed that Ca(OH2 solutions are capable of reducing CO2 below 6%. The H2S concentration was reduced to 89%, 90%, 86%, 85%, and 96% for treating with 10 g of FeCl2, Feo (with pH, Fe2O3, Feo, and activated carbon, respectively. The H2O concentration was reduced to 0.2%, 0.7%, 0.2%, 0.2%, and 0.3% for treating raw biogas with 10 g of silica gel and Na2SO4 for runs R1, R2, R3, R4, and R5, respectively. Thus, given the successful contaminant elimination, the combined absorption and adsorption process is a feasible system for biogas purification.

  20. A novel method of adrenaline concentration detection using fiber optical biosensor based on the catalysis of iron(II) phthalocyanine

    Science.gov (United States)

    Zhou, Xuan; Huang, Jun; Li, Mingtian; Wang, Bin

    2008-12-01

    As an effective alternative to the nature enzyme, metallophthalocyanine (MPc), having the advantages of easy accessibility, good stability and low cost, are used as catalyzer for the adrenaline (AD) oxidation. In this paper, the oxidation of AD by dioxygen using iron(II) phthalocyanine (FePc) as the catalyst was studied by electronic absorption spectra. The experimental results indicate that the oxidation product of AD catalyzed by FePc is adrenochrome with characteristic peaks at 298 nm and 267 nm. The catalytic activities of FePc are evaluated by the ratios of the absorbance at 298 nm of adrenochrome. The optimal concentration, pH and temperature for the oxidation of AD are 5.0×10-5 M, 8.0 and 55 oC, respectively. By using lock-in technology, the fiber optic adrenaline biosensor based on FePc catalysis and fluorescence quenching was fabricated and studied. A linear relationship between φ, the phase delay of the sensor head, and AD concentration was observed in the range of 2.0×10-6 to 9.0×10-6 M and 2.0×10-5 to 9.0×10-5 M. The standard deviation (SD) values are 4.7×10-8 (n = 5) and 5.9×10-7 (n = 5) M, respectively, while the detection limit is 4.0×10-7 M. The biosensor has the response time of about 15 min and the preferred reproducibility and stability.

  1. A method to simultaneously determining the reduction in PAH dissolved concentrations and bioaccessibility in carbon amended soils

    DEFF Research Database (Denmark)

    Marchal, Geoffrey; Smith, Kilian E. C.; Rein, Arno

    In order to investigate the potential of different soil amendments (activated charcoal (AC), charcoal (biochar), compost) to sorb PAHs and their effect on bioaccessibility and biodegradation of PAHs in soil, a method was developed that can determine simultaneously the changes in PAH dissolved...

  2. Comparison of different concentration methods for the detection of hepatitis A virus and calicivirus from bottled natural mineral waters

    DEFF Research Database (Denmark)

    Di Pasquale, S.; Paniconi, M; Auricchio, B

    2010-01-01

    To evaluate the efficiency of different recovery methods of viral RNA from bottled water, a comparison was made of 2 positively and 2 negatively charged membranes that were used for absorbing and releasing HAV virus particles during the filtration of viral spiked bottled water. All the 4 membrane...

  3. Selecting Cooking Methods to Decrease Persistent Organic Pollutant Concentrations in Food of Animal Origin Using a Consensus Decision-Making Model

    Directory of Open Access Journals (Sweden)

    Xiao Tan

    2017-02-01

    Full Text Available Persistent organic pollutants (POPs pose serious threats to human health. Increasing attention has been paid to POPs to protect the environment and prevent disease. Humans are exposed to POPs through diet (the major route, inhaling air and dust and skin contact. POPs are very lipophilic and hydrophobic, meaning that they accumulate in fatty tissues in animals and can biomagnify. Humans can therefore be exposed to relatively high POP concentrations in food of animal origin. Cooking animal products can decrease the POP contents, and different cooking methods achieve different reduction rates. Here, a consensus decision-making model with interval preference relations is used to prioritize cooking methods for specific animal products in terms of reducing POP concentrations. Two consistency mathematical expressions (I-consistency and I I -consistency are defined, then the ideal interval preference relations are determined for the cooking methods with respect to different social choice principles. The objective is to minimize disparities between individual judgments and the ideal consensus judgment. Consistency is used as a constraint to determine the rationality of the consistency definitions. A numerical example indicated that baking is the best cooking method for decreasing POP concentrations in grass carp. The I-consistency results were more acceptable than the I I -consistency results.

  4. Development of particle induced gamma-ray emission methods for nondestructive determination of isotopic composition of boron and its total concentration in natural and enriched samples.

    Science.gov (United States)

    Chhillar, Sumit; Acharya, Raghunath; Sodaye, Suparna; Pujari, Pradeep K

    2014-11-18

    We report simple particle induced gamma-ray emission (PIGE) methods using a 4 MeV proton beam for simultaneous and nondestructive determination of the isotopic composition of boron ((10)B/(11)B atom ratio) and total boron concentrations in various solid samples with natural isotopic composition and enriched with (10)B. It involves measurement of prompt gamma-rays at 429, 718, and 2125 keV from (10)B(p,αγ)(7)Be, (10)B(p, p'γ)(10)B, and (11)B(p, p'γ)(11)B reactions, respectively. The isotopic composition of boron in natural and enriched samples was determined by comparing peak area ratios corresponding to (10)B and (11)B of samples to natural boric acid standard. An in situ current normalized PIGE method, using F or Al, was standardized for total B concentration determination. The methods were validated by analyzing stoichiometric boron compounds and applied to samples such as boron carbide, boric acid, carborane, and borosilicate glass. Isotopic compositions of boron in the range of 0.247-2.0 corresponding to (10)B in the range of 19.8-67.0 atom % and total B concentrations in the range of 5-78 wt % were determined. It has been demonstrated that PIGE offers a simple and alternate method for total boron as well as isotopic composition determination in boron based solid samples, including neutron absorbers that are important in nuclear technology.

  5. Application of the Data Mining Methods to Assess the Impact of Meteorological Conditions on the Episodes of High Concentrations of PM10 along the Polish - Czech Border

    Science.gov (United States)

    Ośródka, Leszek; Krajny, Ewa; Wojtylak, Marek

    2018-01-01

    The paper presents an attempt to use selected data mining methods to determine the influence of a complex of meteorological conditions on the concentrations of PM10 (PM2.5) proffering the example of the regions of Silesia and Northern Moravia. The collection of standard meteorological data has been supplemented by increments and derivatives of measurable weather elements such as vertical pseudo-gradient of air temperature. The main objective was to develop a universal methodology for the assessment of these impacts, i.e. one that would be independent of the analysed pollution. The probability of occurrence (at a given location) of the assumed concentration level as exceeding the value of the specified distributional quintile was adopted as the discriminant of the incidence. As a result of the analyses conducted, incidences of elevated concentrations of air pollution particulate matter PM10 have been identified and the types of weather responsible for the emergence of such situations have also been determined.

  6. Towards a zero-blank, preconcentration-free voltammetric method for iron analysis at picomolar concentrations in unbuffered seawater.

    Science.gov (United States)

    Laglera, Luis M; Caprara, Salvatore; Monticelli, Damiano

    2016-04-01

    A method with negligible blank values for the determination of total iron at the ultratrace level in seawater has been optimized and validated exploring for the first time the performance and limitations of Adsorptive Cathodic Stripping Voltammetry (AdCSV) in non-buffered solutions. The method is based on the CSV determination of the Fe-dihydroxynaphthalene (DHN) complex using atmospheric oxygen to catalytically enhance the signal via hydrogen peroxide formation at the electrode/solution interface. The accumulation of hydroxyl ions, the by-product of the hydrogen peroxide formation, increased the pH in the diffusion layer in the absence of buffer bringing it to 9, the optimum for the analytical performance of the method. Voltammograms in UV digested seawater showed no stability or reproducibility drawbacks. The negligible, lower than 5pM, blank level, is due to the simplicity of the procedure requiring no sample manipulation and a maximum of three reagents only, necessarily the ligand DHN and a base only for those samples previously acidified to raise the pH to circumneutral values (here HCl and NH3 according to common trace metals protocols). These reagents do not require cleaning before use, further simplifying the overall procedure. Analysis of seawater previously acidified at pH ~1.5 with HCl and neutralized with ammonia showed interferences due to the buffering properties of the NH3/NH4Cl couple and the transient formation of a volatile electroactive interference that can be easily removed by simply allowing a set time before analysis. In general, the proposed method features several advantages, including high sample throughput, an excellent limit of detection at 12pM, minimum sample handling (no preconcentration or change of matrix is required), cost effectiveness and mainly a negligible blank. The method was successfully validated using open ocean consensus samples (SAFe D2 and S). Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Methods for preparation of mixtures of gases in air at the parts-per-billion to parts-per-million concentration range for calibration of monitors

    International Nuclear Information System (INIS)

    Karpas, Z.; Melloul, S.; Pollevoy, Y.; Matmor, A.

    1992-05-01

    Static and dynamic methods for generating mixture of gases and vapors in air at the parts-per-billion (ppb) to parts-per-million (ppm) concentration range were surveyed. The dynamic methods include: a dynamic flow and mixing system; injection of samples into large volumes of air; exponential dilution; permeation and diffusion tubes; and generation of the target gas by chemical reaction or electrolysis. The static methods include preparation of mixtures by weighing the components, by volumetric mixing and by partial pressure method. The principles governing the utilization of these methods for the appropriate applications were discussed, and examples in which they were used to calibrate an ion mobility spectrometer (IMS) were given. (authors)

  8. Comparative measurements of ambient atmospheric concentrations of ice nucleating particles using multiple immersion freezing methods and a continuous flow diffusion chamber

    Science.gov (United States)

    DeMott, Paul J.; Hill, Thomas C. J.; Petters, Markus D.; Bertram, Allan K.; Tobo, Yutaka; Mason, Ryan H.; Suski, Kaitlyn J.; McCluskey, Christina S.; Levin, Ezra J. T.; Schill, Gregory P.; Boose, Yvonne; Rauker, Anne Marie; Miller, Anna J.; Zaragoza, Jake; Rocci, Katherine; Rothfuss, Nicholas E.; Taylor, Hans P.; Hader, John D.; Chou, Cedric; Huffman, J. Alex; Pöschl, Ulrich; Prenni, Anthony J.; Kreidenweis, Sonia M.

    2017-09-01

    A number of new measurement methods for ice nucleating particles (INPs) have been introduced in recent years, and it is important to address how these methods compare. Laboratory comparisons of instruments sampling major INP types are common, but few comparisons have occurred for ambient aerosol measurements exploring the utility, consistency and complementarity of different methods to cover the large dynamic range of INP concentrations that exists in the atmosphere. In this study, we assess the comparability of four offline immersion freezing measurement methods (Colorado State University ice spectrometer, IS; North Carolina State University cold stage, CS; National Institute for Polar Research Cryogenic Refrigerator Applied to Freezing Test, CRAFT; University of British Columbia micro-orifice uniform deposit impactor-droplet freezing technique, MOUDI-DFT) and an online method (continuous flow diffusion chamber, CFDC) used in a manner deemed to promote/maximize immersion freezing, for the detection of INPs in ambient aerosols at different locations and in different sampling scenarios. We also investigated the comparability of different aerosol collection methods used with offline immersion freezing instruments. Excellent agreement between all methods could be obtained for several cases of co-sampling with perfect temporal overlap. Even for sampling periods that were not fully equivalent, the deviations between atmospheric INP number concentrations measured with different methods were mostly less than 1 order of magnitude. In some cases, however, the deviations were larger and not explicable without sampling and measurement artifacts. Overall, the immersion freezing methods seem to effectively capture INPs that activate as single particles in the modestly supercooled temperature regime (> -20 °C), although more comparisons are needed in this temperature regime that is difficult to access with online methods. Relative to the CFDC method, three immersion freezing

  9. A method for the analysis of perfluorinated compounds in environmental and drinking waters and the determination of their lowest concentration minimal reporting levels.

    Science.gov (United States)

    Boone, J Scott; Guan, Bing; Vigo, Craig; Boone, Tripp; Byrne, Christian; Ferrario, Joseph

    2014-06-06

    A trace analytical method was developed for the determination of seventeen specific perfluorinated chemicals (PFCs) in environmental and drinking waters. The objectives were to optimize an isotope-dilution method to increase the precision and accuracy of the analysis of the PFCs and to eliminate the need for matrix-matched standards. A 250 mL sample of environmental or drinking water was buffered to a pH of 4, spiked with labeled surrogate standards, extracted through solid phase extraction cartridges, and eluted with ammonium hydroxide in methyl tert-butyl ether: methanol solution. The sample eluents were concentrated to volume and analyzed by liquid chromatography/tandem mass spectrometry (LC-MS/MS). The lowest concentration minimal reporting levels (LCMRLs) for the seventeen PFCs were calculated and ranged from 0.034 to 0.600 ng/L for surface water and from 0.033 to 0.640 ng/L for drinking water. The relative standard deviations (RSDs) for all compounds were acid (PFBA) and other short chain PFCs. Various surface water and drinking water samples were used during method development to optimize this method. The method was used to evaluate samples from the Mississippi River at New Orleans and drinking water samples from a private residence in that same city. The method was also used to determine PFC contamination in well water samples from a fire training area where perfluorinated foams were used in training to extinguish fires. Published by Elsevier B.V.

  10. Standard test method for determination of low concentrations of uranium in oils and organic liquids by X-ray fluorescence

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method covers the steps necessary for the preparation and analysis by X-ray fluorescence (XRF) of oils and organic solutions containing uranium. Two different preparation techniques are described. 1.2 The procedure is valid for those solutions containing 20 to 2000 μg uranium per mL as presented to the spectrometer for the solution technique and 200 to 50 000 μg uranium per g for the pellet technique. 1.3 This test method requires the use of an appropriate internal standard. Care must be taken to ascertain that samples analyzed by this test method do not contain the internal standard or that this contamination, whenever present, has been corrected for mathematically. Such corrections are not addressed in this procedure. Care must be taken that the internal standard and sample medium are compatible; that is, samples must be miscible with tri-n-butyl phosphate (TBP) and must not remove the internal standard from solution. Alternatively, a scatter line may be used as the internal standard. 1....

  11. Methods for estimating concentrations and loads of selected constituents in tributaries to Lake Houston near Houston, Texas

    Science.gov (United States)

    Lee, Michael T.

    2012-01-01

    Since December 2005, the U.S. Geological Survey, in cooperation with the City of Houston, Texas, has been assessing the quality of the water flowing into Lake Houston. Continuous in-stream water-quality monitors measured streamflow and other physical water quality properties at stations in Spring Creek near Spring, Tex., and East Fork San Jacinto River near New Caney, Tex. Additionally, discrete water-quality samples were periodically collected on these tributaries and analyzed for selected constituents of concern. Data from the discrete water-quality samples collected during 2005-9, in conjunction with the real-time streamflow data and data from the continuous in-stream water-quality monitors, provided the basis for developing regression equations for the estimation of concentrations of water-quality constituents of these source watersheds to Lake Houston. The output of the regression equations are available through the interactive National Real-Time Water Quality Web site (http://nrtwq.usgs.gov).

  12. Effect of Temperature, Solvent and Precursor Concentration on Anti-Aggregation of ZnO Nanoparticles Prepared by Polyol Method.

    Science.gov (United States)

    Shanmugaml, Sathish; Muthu, Kesavan; Subramanian, Balakumar

    2016-01-01

    We have investigated the formation mechanism of ZnO microspheres in polyol medium. The synthesis conditions have been varied with respect to temperature, medium and Zn-precursor concentration. The X-ray diffraction (XRD) and Raman spectroscopy result shows that the prepared ZnO nanoparticles are hexagonal wurtzite crystal structure and quite crystalline in nature. High resolution transmission electron microscopy (HRTEM) image indicates that the microsphere consists of aggregated nanoparticles in the range of 6 nm to 15 nm. The samples prepared in ethylene glycol medium shows a characteristic ether bond vibration mode in FTIR and it is additionally confirmed by NMR analysis. Initially, the nanoparticles are self-assembled into loosely packed microsphere and then the particles are densely packed by ether bonds formed between the glycol molecules adsorbed on adjacent particles which then grow as perfect microspheres. The sample prepared in EG medium at 150 °C did not show much aggregation. This study proposes the possible mechanism for the formation of ZnO microsphere.

  13. The Huber’s Method-based Gas Concentration Reconstruction in Multicomponent Gas Mixtures from Multispectral Laser Measurements under Noise Overshoot Conditions

    Directory of Open Access Journals (Sweden)

    V. A. Gorodnichev

    2016-01-01

    Full Text Available Laser gas analysers are the most promising for the rapid quantitative analysis of gaseous air pollution. A laser gas analysis problem is that there are instable results in reconstruction of gas mixture components concentration under real noise in the recorded laser signal. This necessitates using the special processing algorithms. When reconstructing the quantitative composition of multi-component gas mixtures from the multispectral laser measurements are efficiently used methods such as Tikhonov regularization, quasi-solution search, and finding of Bayesian estimators. These methods enable using the single measurement results to determine the quantitative composition of gas mixtures under measurement noise. In remote sensing the stationary gas formations or in laboratory analysis of the previously selected (when the gas mixture is stationary air samples the reconstruction procedures under measurement noise of gas concentrations in multicomponent mixtures can be much simpler. The paper considers a problem of multispectral laser analysis of stationary gas mixtures for which it is possible to conduct a series of measurements. With noise overshoots in the recorded laser signal (and, consequently, overshoots of gas concentrations determined by a single measurement must be used stable (robust estimation techniques for substantial reducing an impact of the overshoots on the estimate of required parameters. The paper proposes the Huber method to determine gas concentrations in multicomponent mixtures under signal overshoot. To estimate the value of Huber parameter and the efficiency of Huber's method to find the stable estimates of gas concentrations in multicomponent stationary mixtures from the laser measurements the mathematical modelling was conducted. Science & Education of the Bauman MSTU 108 The mathematical modelling results show that despite the considerable difference among the errors of the mixture gas components themselves a character of

  14. Determination of the nitrogen concentration in epitaxial layers of GaAs /SUB 1-x/ p /SUB x/ by the optical method

    International Nuclear Information System (INIS)

    Lupal, M.V.; Klot, B; Nikhter, K.; Pikhtin, A.N.; Trapp, M.

    1986-01-01

    This paper determines the dependence of the cross section for absorption in the A /SUB N/ line of a bound exciton on the nitrogen content in the solid solution GaAs /SUB 1-x/ P /SUB x/ by comparing the results of optical measurements with the data from secondary ionic mass spectrometry, and these results are used to study the effect of technological factors on the nitrogen concentration epitaxial layers obtained by the gas-transport method. Doping was carried out with nitrogen by injecting ammonia into the reactor zone; the partial pressure of the ammonia was varied from 1 to 25 kPa. Aside from nitrogen, the authors doped the layers with shallow donor Te. It is established that the solubility of nitrogen in the solid solution decreases as the arsenic content increases when the convenient optical method for determining the nitrogen concentration in epitaxial GaAs /SUB 1-x/ P /SUB x/ layers is used

  15. False Negative Rates of a Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis Surrogates via Real-Time PCR

    Energy Technology Data Exchange (ETDEWEB)

    Hutchison, Janine R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Piepel, Gregory F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Amidan, Brett G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sydor, Michael A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kaiser, Brooke L.D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-06-01

    Surface sampling for Bacillus anthracis spores has traditionally relied on detection via bacterial cultivation methods. Although effective, this approach does not provide the level of organism specificity that can be gained through molecular techniques. False negative rates (FNR) and limits of detection (LOD) were determined for two B. anthracis surrogates with modified rapid viability-polymerase chain reaction (mRV-PCR) following macrofoam-swab sampling. This study was conducted in parallel with a previously reported study that analyzed spores using a plate-culture method. B. anthracis Sterne (BAS) or B. atrophaeus Nakamura (BG) spores were deposited onto four surface materials (glass, stainless steel, vinyl tile, and plastic) at nine target concentrations (2 to 500 spores/coupon; 0.078 to 19.375 colony-forming units [CFU] per cm2). Mean FNR values for mRV-PCR analysis ranged from 0 to 0.917 for BAS and 0 to 0.875 for BG and increased as spore concentration decreased (over the concentrations investigated) for each surface material. FNRs based on mRV-PCR data were not statistically different for BAS and BG, but were significantly lower for glass than for vinyl tile. FNRs also tended to be lower for the mRV-PCR method compared to the culture method. The mRV-PCR LOD95 was lowest for glass (0.429 CFU/cm2 with BAS and 0.341 CFU/cm2 with BG) and highest for vinyl tile (0.919 CFU/cm2 with BAS and 0.917 CFU/cm2 with BG). These mRV-PCR LOD95 values were lower than the culture values (BAS: 0.678 to 1.023 CFU/cm2 and BG: 0.820 to 1.489 CFU/cm2). The FNR and LOD95 values reported in this work provide guidance for environmental sampling of Bacillus spores at low concentrations.

  16. Automated flow-injection method for cadmium determination with pre-concentration and reagent preparation on-line

    Directory of Open Access Journals (Sweden)

    María S. Di Nezio

    2005-02-01

    Full Text Available The spectrophotometric determination of Cd(II using a flow injection system provided with a solid-phase reactor for cadmium preconcentration and on-line reagent preparation, is described. It is based on the formation of a dithizone-Cd complex in basic medium. The calibration curve is linear between 6 and 300 µg L-1 Cd(II, with a detection limit of 5.4 µg L-1, an RSD of 3.7% (10 replicates in duplicate and a sample frequency of 11.4 h-1. The proposed method was satisfactorily applied to the determination of Cd(II in surface, well and drinking waters.

  17. An Evaluation of the Accuracy of the Subtraction Method Used for Determining Platelet Counts in Advanced Platelet-Rich Fibrin and Concentrated Growth Factor Preparations

    Directory of Open Access Journals (Sweden)

    Taisuke Watanabe

    2017-01-01

    Full Text Available Platelet concentrates should be quality-assured of purity and identity prior to clinical use. Unlike for the liquid form of platelet-rich plasma, platelet counts cannot be directly determined in solid fibrin clots and are instead calculated by subtracting the counts in other liquid or semi-clotted fractions from those in whole blood samples. Having long suspected the validity of this method, we herein examined the possible loss of platelets in the preparation process. Blood samples collected from healthy male donors were immediately centrifuged for advanced platelet-rich fibrin (A-PRF and concentrated growth factors (CGF according to recommended centrifugal protocols. Blood cells in liquid and semi-clotted fractions were directly counted. Platelets aggregated on clot surfaces were observed by scanning electron microscopy. A higher centrifugal force increased the numbers of platelets and platelet aggregates in the liquid red blood cell fraction and the semi-clotted red thrombus in the presence and absence of the anticoagulant, respectively. Nevertheless, the calculated platelet counts in A-PRF/CGF preparations were much higher than expected, rendering the currently accepted subtraction method inaccurate for determining platelet counts in fibrin clots. To ensure the quality of solid types of platelet concentrates chairside in a timely manner, a simple and accurate platelet-counting method should be developed immediately.

  18. The effect of phosphoric acid concentration on the synthesis of nano-whiskers of calcium metaphosphate by chemical precipitation Method

    Science.gov (United States)

    Yao, Nengjian; Zhang, Yin; Kong, Deshuang; Zhu, Jianping; Tao, Yaqiu; Qiu, Tai

    2011-10-01

    Calcium metaphosphate (CMP) nano-whiskers were produced by a chemical precipitation method. In order to produce nano-powders, CMP was prepared by the mixing of two precursors, calcium oxide (CaO) and phosphate acid (H3PO4). Sparingly soluble chemicals, the Ca/P ratio of the mixture was set to be 0.50 to produce stoichiometric CMP, were chemical agitated in phosphate acid solution. At least 3 hours of pre-hydrolysis of phosphorus precursor were required to obtain CMP phase. The CMP powders were dried in a drying oven at 60 °C for 7 days and then followed by a heat treatment at 390 °C for 8hours. The obtained powder was analyzed using XRD, XRF, FT-IR, SEM, TG-DTA, Zeta Potential Meter, Specific Surface Area, and Particle Size Analyzer. The results showed that obtained CMP nano-whiskers have a significantly powder characteristics.

  19. The effect of cotton-based collection methods on eosinophil cationic protein (ECP concentrations detected in saliva

    Directory of Open Access Journals (Sweden)

    Teck Yee Wong

    2008-11-01

    Full Text Available Teck Yee Wong, David Koh, Andrew Wee, Vivian Ng, Yong Tat Koh, Zhenjie Sum, Gerald KohDepartment of Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeBackground: Salivary eosinophil cationic protein (ECP level has the potential to be an assessment tool for asthma. Its measurement is not well-established and needs standardization. We studied how passive drool (PD and two commercial devices, Salivette® (cotton-based device and Sorbette® (cellulose–cotton-based-device, may affect ECP levels during collection among healthy subjects.Methods: Study I (n = 10 involved direct sampling of healthy adult subjects with Salivette® and Sorbette®. Study II (n = 33 involved ‘indirect’ sampling of previously collected PD by both devices.Results: In study I, ECP levels were detected in all PD samples but only in three with Sorbette® and none with Salivette® (collection order: PD, Sorbette® and Salivette®. We changed the order of collection (Salivette®, Sorbette®, PD and the results were similar (ECP levels detected in all PD samples, three with Sorbette® and only one with Salivette®. In study II, ECP levels in saliva collected by PD was 12.8 μg/L (median and using Sorbette® and Salivette® were < 2.0 μg/L and 3.4 μg/L respectively (p < 0.01. ECP levels in PD correlated with Sorbette® (rs = 0.79, p < 0.01 and Salivette® (rs = 0.62, p 0.01.Conclusion: Compared to PD, saliva collected using cotton or cellulose-based collection devices resulted in lower measurable ECP levels.Keywords: salivary ECP, collection methods

  20. Remote determination of exposure degree and iron concentration of lunar soils using VIS-NIR spectroscopic methods

    Science.gov (United States)

    Fischer, Erich M.; Pieters, Carle M.

    1994-01-01

    On the Moon, space weathering processes such as micrometeorite bombardment alter the optical properties of lunar soils. As a consequence, lunar soil optical properties are a function not only of composition, but of degree of exposure on the lunar surface as well. In order to accurately assess the compositional properties of the lunar surface using remotely acquired visible and near-infrared spectroscopic data, it is thus necessary either (1) to compare optical properties only of soils characterized by similar degrees of exposure or (2) to otherwise normalize or remove the optical effects due to exposure. Laboratory spectroscopic data for lunar soils are used to develop and test remote spectrocopic methods for determining degree of exposure and for distinguishing between the optical effects due to exposure and those due to composition. A method employing a ratio between reflectances within and outside of the 1 micrometer Fe(2+) crystal field absorption band was developed for remotely identifying highland soils that have reached a steady-state maturity. The relative optical properties of these soils are a function solely of composition and as such can be directly compared. Spectroscopic techniques for accurate quantitative determination of iron content for lunar highland soils are investigated as well. It is shown that approximations of the 1 micrometer Fe(2+) absorption band depth using few to several channel multispectral data or spectroscopic data of inadequate spectral range cannot be used with confidence for compositional analysis. However, band depth measurements derived from continuum-removed high spectral resolution data can be used to calculate the weight percent FeO and relative proportion of iron-bearing silicates in mature lunar highland and mare/highland mixture soils. A preliminary effort to calibrate telescopic band depth to laboratory soil measurements is described.

  1. Recovery Efficiency, False Negative Rate, and Limit of Detection Performance of a Validated Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis Surrogates

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hutchison, Janine R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kaiser, Brooke L. D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Amidan, Brett G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sydor, Michael A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Barrett, Christopher A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-06-16

    The performance of a macrofoam-swab sampling method was evaluated using Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus Nakamura (BG) spores applied at nine low target amounts (2-500 spores) to positive-control plates and test coupons (2 in × 2 in) of four surface materials (glass, stainless steel, vinyl tile, and plastic). Test results from cultured samples were used to evaluate the effects of surrogate, surface concentration, and surface material on recovery efficiency (RE), false negative rate (FNR), and limit of detection. For RE, surrogate and surface material had statistically significant effects, but concentration did not. Mean REs were the lowest for vinyl tile (50.8% with BAS, 40.2% with BG) and the highest for glass (92.8% with BAS, 71.4% with BG). FNR values ranged from 0 to 0.833 for BAS and 0 to 0.806 for BG, with values increasing as concentration decreased in the range tested (0.078 to 19.375 CFU/cm2, where CFU denotes ‘colony forming units’). Surface material also had a statistically significant effect. A FNR-concentration curve was fit for each combination of surrogate and surface material. For both surrogates, the FNR curves tended to be the lowest for glass and highest for vinyl title. The FNR curves for BG tended to be higher than for BAS at lower concentrations, especially for glass. Results using a modified Rapid Viability-Polymerase Chain Reaction (mRV-PCR) analysis method were also obtained. The mRV-PCR results and comparisons to the culture results are discussed in a separate report.

  2. Recovery Efficiency, False Negative Rate, and Limit of Detection Performance of a Validated Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis Surrogates

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hutchison, Janine R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deatherage Kaiser, Brooke L [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Amidan, Brett G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sydor, Michael A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Barrett, Christopher A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-03-31

    The performance of a macrofoam-swab sampling method was evaluated using Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus Nakamura (BG) spores applied at nine low target amounts (2-500 spores) to positive-control plates and test coupons (2 in. × 2 in.) of four surface materials (glass, stainless steel, vinyl tile, and plastic). Test results from cultured samples were used to evaluate the effects of surrogate, surface concentration, and surface material on recovery efficiency (RE), false negative rate (FNR), and limit of detection. For RE, surrogate and surface material had statistically significant effects, but concentration did not. Mean REs were the lowest for vinyl tile (50.8% with BAS, 40.2% with BG) and the highest for glass (92.8% with BAS, 71.4% with BG). FNR values ranged from 0 to 0.833 for BAS and 0 to 0.806 for BG, with values increasing as concentration decreased in the range tested (0.078 to 19.375 CFU/cm2, where CFU denotes ‘colony forming units’). Surface material also had a statistically significant effect. A FNR-concentration curve was fit for each combination of surrogate and surface material. For both surrogates, the FNR curves tended to be the lowest for glass and highest for vinyl title. The FNR curves for BG tended to be higher than for BAS at lower concentrations, especially for glass. Results using a modified Rapid Viability-Polymerase Chain Reaction (mRV-PCR) analysis method were also obtained. The mRV-PCR results and comparisons to the culture results will be discussed in a subsequent report.

  3. Application of bimodal distribution to the detection of changes in uranium concentration in drinking water collected by random daytime sampling method from a large water supply zone.

    Science.gov (United States)

    Garboś, Sławomir; Święcicka, Dorota

    2015-11-01

    The random daytime (RDT) sampling method was used for the first time in the assessment of average weekly exposure to uranium through drinking water in a large water supply zone. Data set of uranium concentrations determined in 106 RDT samples collected in three runs from the water supply zone in Wroclaw (Poland), cannot be simply described by normal or log-normal distributions. Therefore, a numerical method designed for the detection and calculation of bimodal distribution was applied. The extracted two distributions containing data from the summer season of 2011 and the winter season of 2012 (nI=72) and from the summer season of 2013 (nII=34) allowed to estimate means of U concentrations in drinking water: 0.947 μg/L and 1.23 μg/L, respectively. As the removal efficiency of uranium during applied treatment process is negligible, the effect of increase in uranium concentration can be explained by higher U concentration in the surface-infiltration water used for the production of drinking water. During the summer season of 2013, heavy rains were observed in Lower Silesia region, causing floods over the territory of the entire region. Fluctuations in uranium concentrations in surface-infiltration water can be attributed to releases of uranium from specific sources - migration from phosphate fertilizers and leaching from mineral deposits. Thus, exposure to uranium through drinking water may increase during extreme rainfall events. The average chronic weekly intakes of uranium through drinking water, estimated on the basis of central values of the extracted normal distributions, accounted for 3.2% and 4.1% of tolerable weekly intake. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Analytical method for evaluating (and correcting) the impact of outdoor radon concentration on the estimates of percentage of dwellings exceeding reference levels.

    Science.gov (United States)

    Antignani, S; Venoso, G; Carpentieri, C; Bochicchio, F

    2018-02-02

    Outdoor radon concentration contributes to indoor radon levels, generally causing a shift from lognormal distribution of measured radon concentration data distribution, and it makes more challenging the estimation of radon distribution parameters on the basis of the lognormal assumption. In particular, lognormal assumption with no correction could lead to a significantly biased estimate of the percentage of dwellings exceeding a certain level, e.g. a reference level (RL), since this is based on biased estimates of geometric mean (GM) and geometric standard deviation (GSD) of radon concentration distribution. Subtracting to each measured data a constant outdoor radon level can usually compensate data distribution departure from log-normality (except for low radon levels), if the appropriate outdoor level value is chosen by means of a lognormal fit of the data. This approach - already (but not always) used in literature - cannot be applied in cases where all the data of radon concentrations are not available (e.g., for a review study). For these cases, this work presents an analytical method to quantitatively evaluate and correct the impact of outdoor on the lognormal distribution parameter estimates and, in particular, on the percentages of dwellings exceeding radon reference levels. The proposed method is applied to a number of possible situations, with different values of outdoor radon level, GM and GSD. The results show that outdoor radon levels generally produce an underestimation of the actual GSD parameter, which increases as the outdoor level increases, and in the worse cases, could lead to an underestimation higher than 50%. Consequently, if the outdoor contribution is not properly taken into account, the percentage of dwellings exceeding a certain RL is almost always underestimated, even by 80%-90% for RL equal to 300 Bq/m 3 . This could have implications for the classification of areas as regards radon concentration and for the estimation of avertable lung

  5. New, rapid method to measure dissolved silver concentration in silver nanoparticle suspensions by aggregation combined with centrifugation

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Feng, E-mail: fengdongub@gmail.com [University of Birmingham, Institute of Microbiology and Infection, School of Biosciences (United Kingdom); Valsami-Jones, Eugenia [University of Birmingham, School of Geography, Earth and Environmental Sciences (United Kingdom); Kreft, Jan-Ulrich [University of Birmingham, Institute of Microbiology and Infection, School of Biosciences (United Kingdom)

    2016-09-15

    It is unclear whether the antimicrobial activities of silver nanoparticles (AgNPs) are exclusively mediated by the release of silver ions (Ag{sup +}) or, instead, are due to combined nanoparticle and silver ion effects. Therefore, it is essential to quantify dissolved Ag in nanosilver suspensions for investigations of nanoparticle toxicity. We developed a method to measure dissolved Ag in Ag{sup +}/AgNPs mixtures by combining aggregation of AgNPs with centrifugation. We also describe the reproducible synthesis of stable, uncoated AgNPs. Uncoated AgNPs were quickly aggregated by 2 mM Ca{sup 2+}, forming large clusters that could be sedimented in a low-speed centrifuge. At 20,100g, the sedimentation time of AgNPs was markedly reduced to 30 min due to Ca{sup 2+}-mediated aggregation, confirmed by the measurements of Ag content in supernatants with graphite furnace atomic absorption spectrometry. No AgNPs were detected in the supernatant by UV–Vis absorption spectra after centrifuging the aggregates. Our approach provides a convenient and inexpensive way to separate dissolved Ag from AgNPs, avoiding long ultracentrifugation times or Ag{sup +} adsorption to ultrafiltration membranes.

  6. The use of statistical methods for censored data to evaluate the activity concentration of Pb-210 in beans (Phaseolus vulgaris L.).

    Science.gov (United States)

    Mingote, Raquel M; Nogueira, Regina A

    2016-10-01

    A survey of 210 Pb activity concentration, one of the major internal natural radiation sources to man, has been carried in the most common species of beans (Phaseolus vulgaris L.) grown and consumed in Brazil. The representative bean types chosen, Carioca beans and black type sown in the Brazilian Midwestern and Southern regions, have been collected in this study and 210 Pb determined by liquid scintillation spectrometry after separation with chromatographic extraction using Sr-resin. Available values in data set of radioactivity in Brazil (GEORAD) on the 210 Pb activity concentration in black beans grown in Southeastern region have been added to the results of this study with the purpose of to amplify the population considered. Concerning the multiple detection limits and due to the high level of censored observations, a robust semi-parametric statistical method called regression on order statistics (ROS) has been employed to provide a reference value of the 210 Pb in Brazilian beans, which amounted to 41 mBq kg -1 fresh wt. The results suggest that the 210 Pb activity concentration in carioca beans is lower than in black beans. Also evaluated was the 210 Pb activity concentration in vegetable component of a typical diet, which displays lower values than those shown in the literature for food consumed in Europe. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Skincare products containing low concentrations of formaldehyde detected by the chromotropic acid method cannot be safely used in formaldehyde-allergic patients.

    Science.gov (United States)

    Hauksson, I; Pontén, A; Gruvberger, B; Isaksson, M; Engfeldt, M; Bruze, M

    2016-02-01

    Formaldehyde is a well-known contact sensitizer. Formaldehyde releasers are widely used preservatives in skincare products. It has been found that formaldehyde at concentrations allowed by the European Cosmetics Directive can cause allergic contact dermatitis. However, we still lack information on whether formaldehyde at low concentrations affects dermatitis in formaldehyde-allergic individuals. To study the effects of low concentrations of formaldehyde on irritant contact dermatitis in formaldehyde-allergic individuals. Fifteen formaldehyde-allergic individuals and a control group of 12 individuals without contact allergy to formaldehyde and formaldehyde releasers were included in the study. The individuals performed the repeated open application test (ROAT) during 4 weeks with four different moisturizers releasing formaldehyde in concentrations that had been determined as > 40, 20-40, 2·5-10 and 0 p.p.m. by the chromotropic acid (CA) spot test. Dimethyloldimethylhydantoin was used as a formaldehyde releaser in the moisturizers. The ROAT was performed on areas of experimentally induced sodium lauryl sulfate dermatitis. The study was double blind, controlled and randomized. Nine of the 15 formaldehyde-allergic individuals had reappearance or worsening of dermatitis on the areas that were treated with moisturizers containing formaldehyde. No such reactions were observed in the control group (P formaldehyde in the formaldehyde-allergic individuals (P formaldehyde often found in skincare products by the CA method are sufficient to worsen an existing dermatitis in formaldehyde-allergic individuals. © 2015 British Association of Dermatologists.

  8. A method comparison study between two hemoglobinometer models (Hemocue Hb 301 and Hb 201+) to measure hemoglobin concentrations and estimate anemia prevalence among women in Preah Vihear, Cambodia.

    Science.gov (United States)

    Rappaport, A I; Karakochuk, C D; Whitfield, K C; Kheang, K M; Green, T J

    2017-02-01

    Hemoglobin (Hb) concentration is often measured in global health and nutrition surveys to determine anemia prevalence using a portable hemoglobinometer such as the Hemocue® Hb 201+. More recently, a newer model was released (Hemocue Hb 301) utilizing slightly different methods to measure Hb as compared to the older model. The objective was to measure bias and concordance between Hb concentrations using the Hemocue Hb 301 and Hb 201+ models in a rural field setting. Hemoglobin (Hb) concentration was measured using one finger prick of blood (approximately 10 μL) from 175 Cambodian women (18-49 years) using three Hemocue Hb 201+ and three Hb 301 machines. Bias and concordance were measured and plotted. Overall, mean ± SD Hb concentration was 116 ± 13 g/L using the Hb 201+ and 118 ± 12 g/L using the Hb 301; and anemia prevalence (Hb < 120 g/L) was 58% (n = 102) and 58% (n = 101), respectively. Overall bias ± SD was 2.0 ± 10.5 g/L and concordance (95% CI) was 0.63 (0.54, 0.72). Despite the 2 g/L bias detected between models, anemia prevalence was very similar in both models. The two models measured anemia prevalence comparably in this population of women in rural Cambodia. © 2016 John Wiley & Sons Ltd.

  9. A new method for calculating number concentrations of cloud condensation nuclei based on measurements of a three-wavelength humidified nephelometer system

    Science.gov (United States)

    Tao, Jiangchuan; Zhao, Chunsheng; Kuang, Ye; Zhao, Gang; Shen, Chuanyang; Yu, Yingli; Bian, Yuxuan; Xu, Wanyun

    2018-02-01

    The number concentration of cloud condensation nuclei (CCN) plays a fundamental role in cloud physics. Instrumentations of direct measurements of CCN number concentration (NCCN) based on chamber technology are complex and costly; thus a simple way for measuring NCCN is needed. In this study, a new method for NCCN calculation based on measurements of a three-wavelength humidified nephelometer system is proposed. A three-wavelength humidified nephelometer system can measure the aerosol light-scattering coefficient (σsp) at three wavelengths and the light-scattering enhancement factor (fRH). The Ångström exponent (Å) inferred from σsp at three wavelengths provides information on mean predominate aerosol size, and hygroscopicity parameter (κ) can be calculated from the combination of fRH and Å. Given this, a lookup table that includes σsp, κ and Å is established to predict NCCN. Due to the precondition for the application, this new method is not suitable for externally mixed particles, large particles (e.g., dust and sea salt) or fresh aerosol particles. This method is validated with direct measurements of NCCN using a CCN counter on the North China Plain. Results show that relative deviations between calculated NCCN and measured NCCN are within 30 % and confirm the robustness of this method. This method enables simplerNCCN measurements because the humidified nephelometer system is easily operated and stable. Compared with the method using a CCN counter, another advantage of this newly proposed method is that it can obtain NCCN at lower supersaturations in the ambient atmosphere.

  10. Methods and results of reconstruction of 131I concentration in milk from total beta-activity measurements in Belarus after Chernobyl

    International Nuclear Information System (INIS)

    Savkin, Mikhail; Shinkarev, Sergey; Titov, Alexey

    2008-01-01

    Full text: During the first few weeks following the Chernobyl accident a large scale monitoring of radioactive contamination of foodstuffs locally produced was carried out in the most contaminated areas of Belarus. Due to a lack of spectrometric instruments, radiometric devices (DP-100) were used for beta activity measurements mostly of milk and milk products. Because the intake of 131 I with milk was the main contributor of the thyroid dose for the Belarus population, it is very important to reconstruct levels of 131 I in milk for Belarus settlements. The purpose of the paper is to present the methods and results of assessing the 13I concentration in milk based on historical records of total-beta activity measurements carried out in April-June 1986 in Belarus. The results of reconstruction of the 131 I concentration in milk will be used in on-going epidemiologic studies of a cohort of Belarus children. About 20,000 total-beta activity measurements were used in the analysis; for about 50% of those, the measurement result exceeded the minimum detectable activity. Estimates of 131 I concentration in milk at the date of sampling and of time-integrated milk concentrations were reconstructed for 482 settlements in Gomel Oblast and for 100 settlements in Mogilev Oblast, the most contaminated areas in Belarus, where at least one milk measurement was available. The assessment of the 131 I concentrations in milk involved: 1) An analysis of the calibration coefficients of the detectors for radionuclides available in milk (the main radionuclides were 131 I, 132 4Cs, 137 Cs, 89 Sr, 90 Sr); and 2) An assessment of the relative activity distribution of those radionuclides in milk. Only measurements made before 21 May 1986 were considered to be reliable, as the measurements conducted late May and in June were found to be unreliable because of the decrease in 131 I concentrations and the growing influence of other radionuclides with longer half-lives. Analysis of multiple

  11. SEDATION IN COLONOSCOPY BY USING THREE DIFFERENT PROPOFOL INFUSION METHODS AND ANALYSIS OF PLASMA CONCENTRATION LEVELS: A PROSPECTIVE COMPARATIVE STUDY.

    Science.gov (United States)

    Carvalho, Paulo Henrique Boaventura de; Otoch, José Pinhata; Khan, Mohamad Ali; Sakai, Paulo; Guedes, Hugo Gonçalo; Artifon, Everson Luiz de Almeida

    2016-01-01

    The propofolemia becomes directly linked to the clinical effects of this anesthetic and is the focus for studies comparing propofol clinical use, in different administration methods routinely used in endoscopy units where sedation is widely administered to patients. To evaluate the effects of three different regimens of intravenous propofol infusion in colonoscopies. A total of 50 patients that underwent colonoscopies were consecutively assigned to three groups: 1) intermittent bolus infusion; 2) continuous manually controlled infusion; 3) continuous automatic infusion. Patients were monitored with Bispectral IndexTM (BIS) and propofol serum levels were collected at three different timepoints. The development of an original dilution of propofol and an inventive capnography catheter were necessary. Regarding clinical outcomes, statistical differences in agitation (higher in group 1, p=0.001) and initial blood pressure (p=0.008) were found. As for propofol serum levels, findings were similar in consumption per minute (p=0.748) and over time (p=0.830). In terms of cost analysis, group 1 cost was R$7.00 (approximately US$2,25); group2, R$17.50 (approximately US$5,64); and group 3, R$112.70 (approximately US$36,35, pendoscopia. Avaliar os efeitos de três diferentes regimes de infusão de propofol intravenoso em colonoscopias. Ao todo 50 pacientes que foram submetidos à colonoscopia foram consecutivamente divididos em três grupos: 1) infusão em bolus intermitente; 2) perfusão contínua controlada manualmente; 3) infusão automática contínua. Os pacientes foram monitorados com Bispectral IndexTM (BIS) e os níveis séricos de propofol foram coletados em três momentos diferentes. Foi necessário a preparação de uma diluição específica de propofol e o desenvolvimento de um cateter de capnografia original manufaturado para a realização do estudo. Em relação aos desfechos clínicos, houve diferença estatística na agitação (maior no grupo 1, p=0,001) e

  12. Thin concentrator photovoltaic module with micro-solar cells which are mounted by self-align method using surface tension of melted solder

    Science.gov (United States)

    Hayashi, Nobuhiko; Terauchi, Masaharu; Aya, Youichirou; Kanayama, Shutetsu; Nishitani, Hikaru; Nakagawa, Tohru; Takase, Michihiko

    2017-09-01

    We are developing a thin and lightweight CPV module using small size lens system made from poly methyl methacrylate (PMMA) with a short focal length and micro-solar cells to decrease the transporting and the installing costs of CPV systems. In order to achieve high conversion efficiency in CPV modules using micro-solar cells, the micro-solar cells need to be mounted accurately to the irradiated region of the concentrated sunlight. In this study, we have successfully developed self-align method thanks to the surface tension of the melted solder even utilizing commercially available surface-mounting technology (SMT). Solar cells were self-aligned to the specified positions of the circuit board by this self-align method with accuracy within ±10 µm. We actually fabricated CPV modules using this self-align method and demonstrated high conversion efficiency of our CPV module.

  13. The use of portable equipment for the activity concentration index determination of building materials: method validation and survey of building materials on the Belgian market

    International Nuclear Information System (INIS)

    Stals, M.; Verhoeven, S.; Bruggeman, M.; Pellens, V.; Schroeyers, W.; Schreurs, S.

    2014-01-01

    The Euratom BSS requires that in the near future (2015) the building materials for application in dwellings or buildings such as offices or workshops are screened for NORM nuclides. The screening tool is the activity concentration index (ACI). Therefore it is expected that a large number of building materials will be screened for NORM and thus require ACI determination. Nowadays, the proposed standard for determination of building material ACI is a laboratory analyses technique with high purity germanium spectrometry and 21 days equilibrium delay. In this paper, the B-NORM method for determination of building material ACI is assessed as a faster method that can be performed on-site, alternative to the aforementioned standard method. The B-NORM method utilizes a LaBr 3 (Ce) scintillation probe to obtain the spectral data. Commercially available software was applied to comprehensively take into account the factors determining the counting efficiency. The ACI was determined by interpreting the gamma spectrum from 226 Ra and its progeny; 232 Th progeny and 40 K. In order to assess the accuracy of the B-NORM method, a large selection of samples was analyzed by a certified laboratory and the results were compared with the B-NORM results. The results obtained with the B-NORM method were in good correlation with the results obtained by the certified laboratory, indicating that the B-NORM method is an appropriate screening method to assess building material ACI. The B-NORM method was applied to analyze more than 120 building materials on the Belgian market. No building materials that exceed the proposed reference level of 1 mSv/year were encountered. -- Highlights: • Many building materials will have to be tested for NORM activity concentrations. • An on-site NORM analysis method has been developed and validated. • Over 120 building materials on the Belgian market have been analyzed with this method. • The Euratom BSS reference level of 1 mSv/year excess dose will

  14. A sensitive method for the detection of tritium-marked β-indolylacetic acid in plant cells and tissues at physiological and experimental concentrations (1962)

    International Nuclear Information System (INIS)

    Figier, J.; Khau Van Kien, L.; Roux, E.

    1962-01-01

    The localisation of β-indolylacetic acid (A.I.A.), a growth auxin is attempted using nuclear indicators ( 14 C and tritium). The radio - auto-histographic detection method depends on the insolubilization of A.I.A. 'in situ' by picric acid and basic lead acetate at a suitable pH, the A.I.A. being protected from histological solvents. The results of the detections corresponding to physiological responses during growth tests on Pisum, Avena, Phascolus and Vicia, at concentrations of 10 -5 and higher make possible the localisation of tissues in agreement with the auxinic activity and with the relations already known between A.L.A. and cellular formations. By increasing the time of exposures of the sections, it will be possible to attain concentrations which are much lower and more clearly physiological. (authors) [fr

  15. Effect of electrolytes nature and concentration on the morphology and structure of MoS{sub 2} nanomaterials prepared using one-pot solvothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Akram, H., E-mail: akramhanane@yahoo.fr [Instituto de Catálisis y Petroleoquímica, CSIC, C/Marie Curie 2, Cantoblanco, 28049 Madrid (Spain); Laboratoire de Génie Chimique et Valorisation des Ressources, Faculté des Sciences et Techniques de Tanger, Université Abdelmalek Essâadi, B.P. 416 Tangier (Morocco); Mateos-Pedrero, C., E-mail: cmpedrero@yahoo.es [Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculdade de Engenharia da Universidade do Porto Rua Roberto Frias, s/n4200-465, Porto (Portugal); Gallegos-Suárez, E.; Guerrero-Ruíz, A. [Instituto de Catálisis y Petroleoquímica, CSIC, C/Marie Curie 2, Cantoblanco, 28049 Madrid (Spain); Grupo de Diseño y Aplicación de Catalizadores Heterogéneos, Unidad Asociada UNED—ICP (CSIC), Madrid (Spain); Chafik, T. [Laboratoire de Génie Chimique et Valorisation des Ressources, Faculté des Sciences et Techniques de Tanger, Université Abdelmalek Essâadi, B.P. 416 Tangier (Morocco); Rodríguez-Ramos, I. [Instituto de Catálisis y Petroleoquímica, CSIC, C/Marie Curie 2, Cantoblanco, 28049 Madrid (Spain); Grupo de Diseño y Aplicación de Catalizadores Heterogéneos, Unidad Asociada UNED—ICP (CSIC), Madrid (Spain)

    2014-07-01

    Different MoS{sub 2} nanostructures have been obtained following an innovative one-step solvothermal method by changing the concentration and type of the electrolyte while avoiding the use of surfactant. It was found that the chemical nature of the studied electrolyte ((NH{sub 4}){sub 2}CO{sub 3} or KCl) do not significantly affect the morphology and structure of the obtained MoS{sub 2} nanomaterials. Nevertheless, increasing the electrolyte concentration yields to a remarkable modification of the morphology of the resulting MoS{sub 2} from nanospheres to worm-shaped then finally to nanotubes. All the obtained nanomaterials were characterized by X-ray diffraction, (XRD), transmission electron microscopy (TEM, HRTEM), Fourier transformation infra-red spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS).

  16. Pharmacokinetic studies on Wilfactin, a von Willebrand factor concentrate with a low factor VIII content treated with three virus-inactivation/removal methods.

    Science.gov (United States)

    Goudemand, J; Scharrer, I; Berntorp, E; Lee, C A; Borel-Derlon, A; Stieltjes, N; Caron, C; Scherrmann, J M; Bridey, F; Tellier, Z; Federici, A B; Mannucci, P M

    2005-10-01

    In order to correct the primary von Willebrand factor (VWF) defect and avoid supra-physiologic plasma levels of factor VIII, a pure VWF concentrate almost devoid of FVIII was developed and used in France since 1989. The pharmacokinetic (PK) profile of the most recent version of this concentrate (Wilfactin; LFB, Les Ulis, France), treated with three virus-inactivation/removal methods (solvent/detergent, 35 nm filtration, dry heat treatment), was investigated in 25 patients. Seventeen patients with various types of clinically severe von Willebrand disease (VWD) were included in a crossover, randomized trial carried out in five European centers and comparing Wilfactin with concentrates containing both FVIII and VWF (FVIII/VWF). Eight type 3 VWD patients were included in another trial carried out in six French centers comparing Wilfactin with its previous version (Facteur Willebrand-LFB; LFB) that adopted one virus-inactivation method only. For both the measurements evaluated in this study (VWF antigen, VWF:Ag; and VWF ristocetin co-factor activity, VWF:RCo), Wilfactin had a PK profile similar to that of the FVIII/VWF concentrates and of Facteur Willebrand-LFB. VWF:RCo and VWF:Ag recoveries were 2.1 +/- 0.3 and 1.8 +/- 0.3 per IU kg(-1), respectively, and the half-lives were 12.4 +/- 1.8 and 15.9 +/- 1.5 h. The FVIII synthesis rate was 5.8 +/- 1.0 IU dL(-1) h(-1), with a half-life of 15.8 +/- 2.4 h. The PK of VWF and FVIII have not been altered by the three virus-inactivation/removal steps during the manufacturing of Wilfactin.

  17. All-Optical Method to Assess Stromal Concentration of Riboflavin in Conventional and Accelerated UV-A Irradiation of the Human Cornea.

    Science.gov (United States)

    Lombardo, Giuseppe; Micali, Norberto Liborio; Villari, Valentina; Serrao, Sebastiano; Lombardo, Marco

    2016-02-01

    We investigated the concentration of riboflavin in human donor corneas during corneal cross-linking using two-photon optical microscopy and spectrophotometry. Eight corneal tissues were de-epithelialized and soaked with 20% dextran-enriched 0.1% riboflavin solution for 30 minutes. After stromal soaking, three tissues were irradiated using a 3 mW/cm2 UV-A device for 30 minutes and three tissues irradiated using a 10 mW/cm2 device for 9 minutes. Two additional tissues were used as positive controls. A Ti:sapphire laser at 810 nm was used to perform two-photon emission fluorescence (TPEF) and second harmonic generation axial scanning measurements in all specimens before and after stromal soaking and after UV-A irradiation. In addition, spectrophotometry was used to collect the absorbance spectra of each tissue at the same time intervals. Analysis of the absorbance spectra and TPEF signals provided measures of the concentration depth profile of riboflavin in corneal stroma. After stromal soaking, the average peak concentration of riboflavin (0.020% ± 0.001%) was found between a stromal depth of 100 and 250 μm; the concentration of riboflavin was almost constant up to 320 ± 53 μm depth, then decreased toward the endothelium, though riboflavin was still enriched in the posterior stroma (0.016%% ± 0.001%). After conventional and accelerated UV-A irradiation, the concentration of riboflavin decreased uniformly 87% ± 2% and 67% ± 3% (P riboflavin in corneal stroma. The method can assist with the assessment of novel riboflavin formulations and different UV-A irradiation protocols.

  18. Relations between DNA- and RNA-based molecular methods for cyanobacteria and microcystin concentration at Maumee Bay State Park Lakeside Beach, Oregon, Ohio, 2012

    Science.gov (United States)

    Stelzer, Erin A.; Loftin, Keith A.; Struffolino, Pamela

    2013-01-01

    Water samples were collected from Maumee Bay State Park Lakeside Beach, Oregon, Ohio, during the 2012 recreational season and analyzed for selected cyanobacteria gene sequences by DNA-based quantitative polymerase chain reaction (qPCR) and RNA-based quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Results from the four DNA assays (for quantifying total cyanobacteria, total Microcystis, and Microcystis and Planktothrix strains that possess the microcystin synthetase E (mcyE) gene) and two RNA assays (for quantifying Microcystis and Planktothrix genera that are expressing the microcystin synthetase E (mcyE) gene) were compared to microcystin concentration results determined by an enzyme-linked immunosorbent assay (ELISA). Concentrations of the target in replicate analyses were log10 transformed. The average value of differences in log10 concentrations for the replicates that had at least one detection were found to range from 0.05 to >0.37 copy per 100 milliliters (copy/100 mL) for DNA-based methods and from >0.04 to >0.17 copy/100 mL for RNA-based methods. RNA has a shorter half-life than DNA; consequently, a 24-hour holding-time study was done to determine the effects of holding time on RNA concentrations. Holding-time comparisons for the RNA-based Microcystis toxin mcyE assay showed reductions in the number of copies per 100 milliliters over 24 hours. The log difference between time 2 hours and time 24 hours was >0.37 copy/100 mL, which was higher than the analytical variability (log difference of >0.17 copy/100 mL). Spearman’s correlation analysis indicated that microcystin toxin concentrations were moderately to highly related to DNA-based assay results for total cyanobacteria (rho=0.69), total Microcystis (rho=0.74), and Microcystis strains that possess the mcyE gene (rho=0.81). Microcystin toxin concentrations were strongly related with RNA-based assay results for Microcystis mcyE gene expression (rho=0.95). Correlation analysis could

  19. Reference values assessment in a Mediterranean population for small dense low-density lipoprotein concentration isolated by an optimized precipitation method

    Directory of Open Access Journals (Sweden)

    Fernández-Cidón B

    2017-06-01

    Full Text Available Bárbara Fernández-Cidón,1–3 Ariadna Padró-Miquel,1 Pedro Alía-Ramos,1 María José Castro-Castro,1 Marta Fanlo-Maresma,4 Dolors Dot-Bach,1 José Valero-Politi,1 Xavier Pintó-Sala,4 Beatriz Candás-Estébanez1 1Clinical Laboratory, Hospital Universitari de Bellvitge, L’Hospitalet de Llobregat, Spain; 2Department of Biochemistry, Molecular Biology and Biomedicine, Autonomous University of Barcelona (UAB, Barcelona, Spain; 3Department of Pharmacotherapy, Pharmacogenetics and Pharmaceutical Technology, Institut d’Investigació Biomèdica de Bellvitge (IDIBELL, L’Hospitalet de Llobregat, Spain; 4Cardiovascular Risk Unit, Hospital Universitari de Bellvitge, L’Hospitalet de Llobregat, Spain Background: High serum concentrations of small dense low-density lipoprotein cholesterol (sd-LDL-c particles are associated with risk of cardiovascular disease (CVD. Their clinical application has been hindered as a consequence of the laborious current method used for their quantification. Objective: Optimize a simple and fast precipitation method to isolate sd-LDL particles and establish a reference interval in a Mediterranean population. Materials and methods: Forty-five serum samples were collected, and sd-LDL particles were isolated using a modified heparin-Mg2+ precipitation method. sd-LDL-c concentration was calculated by subtracting high-density lipoprotein cholesterol (HDL-c from the total cholesterol measured in the supernatant. This method was compared with the reference method (ultracentrifugation. Reference values were estimated according to the Clinical and Laboratory Standards Institute and The International Federation of Clinical Chemistry and Laboratory Medicine recommendations. sd-LDL-c concentration was measured in serums from 79 subjects with no lipid metabolism abnormalities. Results: The Passing–Bablok regression equation is y = 1.52 (0.72 to 1.73 + 0.07x (−0.1 to 0.13, demonstrating no significant statistical differences

  20. Application of a real-time qPCR method to measure the methanogen concentration during anaerobic digestion as an indicator of biogas production capacity.

    Science.gov (United States)

    Traversi, Deborah; Villa, Silvia; Lorenzi, Eugenio; Degan, Raffaella; Gilli, Giorgio

    2012-11-30

    Biogas is an energy source that is produced via the anaerobic digestion of various organic materials, including waste-water sludge and organic urban wastes. Among the microorganisms involved in digestion, methanogens are the major microbiological group responsible for methane production. To study the microbiological equilibrium in an anaerobic reactor, we detected the methanogen concentration during wet digestion processes fed with pre-treated urban organic waste and waste-water sludge. Two different pre-treatments were used in successive experimental digestions: pressure-extrusion and turbo-mixing. Chemical parameters were collected to describe the process and its production. The method used is based on real-time quantitative PCR (RT-qPCR) with the functional gene mcrA as target. First, we evaluated the validity of the analyses. Next, we applied this method to 50 digestate samples and then we performed a statistical analysis. A positive and significant correlation between the biogas production rate and methanogen abundance was observed (r = 0.579, p amount and also the higher methanogen presence (F = 41.190, p biogas/kg TVS (F = 7.053; p < 0.05). The applied method is suitable to describe microbiome into the anaerobic reactor, moreover methanogen concentration may have potential for use as a digestion optimisation tool. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Development and optimization of a nuclear method to determine the lead concentration as an ultra-trace element in ultra-pure water

    International Nuclear Information System (INIS)

    Amara, A.; Giovagnoli, A.; Barrandon, J.N.

    1994-01-01

    Here we intend to perfect a nuclear analytical technique for the determination of lead concentration as an ultra-trace element in ultra-pure water Inmost cases the analysis of an aqueous solution is made by non-nuclear methods, therefore methods which are sensitive to the chemical form of the element to be determined. To ovoid this problem we developed a nuclear technique using a cyclotron,which allows the determination of the lead concentration in any of its chemical forms. We studied the possibilities of several incident beams, like neutral particles and charged particles. Proton activation showed to be the most sensitive of all the irradiation procedures. Several points have though be studied and developed: - an irradiation cell for liquids irradiation under a strong proton current; - the bismuth chemical separation. This element has two radio-isotopes allowing the determination of lead;-optimize the experimental irradiation and measurements parameters in order to reach the lower detection limit. At last an intercomparison of several techniques has been made for different standards. It clearly showed that, contrary to atomic,potentiometric or mass spectrometry methods,only activation technique give accurate and reproducible results. (author).1 fig., 2 tabs., 4 refs

  2. Concentration device

    DEFF Research Database (Denmark)

    2013-01-01

    A concentration device (2) for filter filtration concentration of particles (4) from a volume of a fluid (6). The concentration device (2) comprises a filter (8) configured to filter particles (4) of a predefined size in the volume of the fluid (6). The concentration device (2) comprises...

  3. False Negative Rates of a Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis Surrogates via Real-Time PCR

    Energy Technology Data Exchange (ETDEWEB)

    Hutchison, Janine R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Piepel, Gregory F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Amidan, Brett G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sydor, Michael A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deatherage Kaiser, Brooke L [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-05-01

    Surface sampling for Bacillus anthracis spores has traditionally relied on detection via bacterial cultivation methods. Although effective, this approach does not provide the level of organism specificity that can be gained through molecular techniques. False negative rates (FNR) and limits of detection (LOD) were determined for two B. anthracis surrogates with modified rapid viability-polymerase chain reaction (mRV-PCR) following macrofoam-swab sampling. This study was conducted in parallel with a previously reported study that analyzed spores using a plate-culture method. B. anthracis Sterne (BAS) or B. atrophaeus Nakamura (BG) spores were deposited onto four surface materials (glass, stainless steel, vinyl tile, and plastic) at nine target concentrations (2 to 500 spores/coupon; 0.078 to 19.375 colony-forming units [CFU] per cm²). Mean FNR values for mRV-PCR analysis ranged from 0 to 0.917 for BAS and 0 to 0.875 for BG and increased as spore concentration decreased (over the concentrations investigated) for each surface material. FNRs based on mRV-PCR data were not statistically different for BAS and BG, but were significantly lower for glass than for vinyl tile. FNRs also tended to be lower for the mRV-PCR method compared to the culture method. The mRV-PCR LOD₉₅ was lowest for glass (0.429 CFU/cm² with BAS and 0.341 CFU/cm² with BG) and highest for vinyl tile (0.919 CFU/cm² with BAS and 0.917 CFU/cm² with BG). These mRV-PCR LOD₉₅ values were lower than the culture values (BAS: 0.678 to 1.023 CFU/cm² and BG: 0.820 to 1.489 CFU/cm²). The FNR and LOD₉₅ values reported in this work provide guidance for environmental sampling of Bacillus spores at low concentrations.

  4. Non-invasive in vivo determination of the carotenoids beta-carotene and lycopene concentrations in the human skin using the Raman spectroscopic method

    Energy Technology Data Exchange (ETDEWEB)

    Darvin, M E [Center of Experimental and Applied Cutaneous Physiology (CCP), Department of Dermatology, Charite University Hospital, Berlin (Germany); Gersonde, I [Institute of Medical Physics and Laser Medicine, Charite University Hospital, Berlin (Germany); Meinke, M [Institute of Medical Physics and Laser Medicine, Charite University Hospital, Berlin (Germany); Sterry, W [Center of Experimental and Applied Cutaneous Physiology (CCP), Department of Dermatology, Charite University Hospital, Berlin (Germany); Lademann, J [Center of Experimental and Applied Cutaneous Physiology (CCP), Department of Dermatology, Charite University Hospital, Berlin (Germany)

    2005-08-07

    Resonance Raman spectroscopy was used as a fast and non-invasive optical method of measuring the absolute concentrations of beta-carotene and lycopene in living human skin. Beta-carotene and lycopene have different absorption values at 488 and 514.5 nm and, consequently, the Raman lines for beta-carotene and lycopene have different scattering efficiencies at 488 and 514.5 nm excitations. These differences were used for the determination of the concentrations of beta-carotene and lycopene. Using multiline Ar{sup +} laser excitation, clearly distinguishable carotenoid Raman spectra can be obtained which are superimposed on a large fluorescence background. The Raman signals are characterized by two prominent Stokes lines at 1160 and 1525 cm{sup -1}, which have nearly identical relative intensities. Both substances were detected simultaneously. The Raman spectra are obtained rapidly, i.e. within about 10 s, and the required laser light exposure level is well within safety standards. The disturbance of the measurements by non-homogeneous skin pigmentation was avoided by using a relatively large measuring area of 35 mm{sup 2}. It was shown that beta-carotene and lycopene distribution in human skin strongly depends upon the skin region studied and drastically changed inter-individually. Skin beta-carotene and lycopene concentrations are lower in smokers than in non-smokers and higher in the vegetarian group.

  5. Effect of Promoter Concentration on CO2 Separation Using K2CO3 With Reactive Absorption Method in Reactor Packed Column

    Directory of Open Access Journals (Sweden)

    Monde Junety

    2018-01-01

    Full Text Available The presence of carbon dioxide (CO2 in the gas is not expected because CO2 can reduce heating value and CO2 is the major emission contributor into the atmosphere. Various separation technologies can be used to reduce CO2 content and improve quality of gas. Chemical or reactive absorption is most widely used because it provides higher removal rate. This paper will study the effect of the addition di ethanolamine (DEA concentration into aqueous 30wt.% potassium carbonate(K2CO3 with reactive absorption method in a reactor packed column at temperature from 40°C to 80°C, DEA concentration range of (1% - 3% and absorbent flow rate (0.5, 0.75 and 1 L. min1. Contacting the gas and absorbent are countercurrent flow in packed column with 1.5 m high and 50 mm in diameter. The absorption column was randomly packed with a packing material raschig rings 5 mm in diameter. The CO2 loading in the liquid samples was determined by titration. It is found that the best result of CO2 loading is 0.065594 mole/mole K2CO3 and CO2 removal 28%. The result show that the loading capacity (mole CO2/mole K2CO3 and CO2 removal increased with the increase of DEA concentration.

  6. Influence of Er(3+) concentration on the photoluminescence characteristics and excitation mechanism of Gd2O3:Er(3+) phosphor synthesized via a solid-state reaction method.

    Science.gov (United States)

    Tamrakar, R K; Bisen, D P; Bramhe, N

    2015-08-01

    An Er(3+) -doped phosphor of Gd2O3(Gd2O3:Er(3+)) was prepared using a conventional solid-state reaction method. The structure and particle size were determined from X-ray powder diffraction measurements. The average particle size of the phosphor was in between 20 and 50 nm. The particle size and structure of the phosphor were further confirmed by transmission electron microscopy (TEM) analysis. Luminescence spectra were recorded under excitation wavelengths of 275, 380, 515 and 980 nm. The visible upconversion and downconversion luminescence spectra of the Gd2O3:Er(3+) phosphor were investigated as a function of Er(3+) ion concentration. The upconverted emission at 980 nm excitation shows enhanced red emission with respect to green emission as the dopant concentration increased. Similar results were observed for downconversion emission under 275 and 380 nm excitation wavelengths. The mechanisms responsible for populating the (4)S3/2 and (4)F9/2 levels, for green and red emissions, respectively, are different for different excitations and for different concentrations of Er(3+). Copyright © 2014 John Wiley & Sons, Ltd.

  7. Effects of solution concentration and capping agents on the properties of potassium titanyl phosphate noparticles synthesized using a co-precipitation method

    Science.gov (United States)

    Gharibshahian, E.; Jafar Tafershi, M.; Fazli, M.

    2018-05-01

    In this study, KTiOPO4 (KTP) nanoparticles were synthesized using a co-precipitation method. The effects of the solution concentration (M) and capping agents, such as PVA, oxalic acid, glycine, triethanolamine, and L-alanine, on the structural, microstructural, and optical properties of the products were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. Decreasing the solution concentration decreased the crystallite size from 53.07 nm (for M = 2) to 39.42 nm (for M = 0.5). After applying different capping agents to the sample at the optimum concentration (M = 0.5), the crystallite size decreased again and grains as small as 10.61 nm were obtained. XRD and FTIR analyses indicated the formation of KTP nanoparticles with an orthorhombic structure in all of the samples. The optical band gap increased as the crystallite size decreased. Different morphological patterns such as spherical, needle shaped, polyhedron, and tablet forms were observed in the nanoparticles, which were correlated with the effects of the capping agents employed.

  8. A comparison of agar dilution with the Calibrated Dichotomous Sensitivity (CDS) and Etest methods for determining the minimum inhibitory concentration of ceftriaxone against Neisseria gonorrhoeae.

    Science.gov (United States)

    Enriquez, Rodney P; Goire, Namraj; Kundu, Ratan; Gatus, Barrie J; Lahra, Monica M

    2016-09-01

    The objective of this study was to compare the Calibrated Dichotomous Sensitivity (CDS) based agar dilution (CDS AD) method with the Etest (bioMérieux SA) methods using 2 method protocols for determining the minimum inhibitory concentration (MIC) of ceftriaxone against Neisseria gonorrhoeae. The two method protocols were the manufacturer's protocol for which the Clinical and Laboratory Standards Institute (CLSI) interpretative criteria for Neisseria gonorrhoeae could be applied, and the CDS-adapted protocol. Comparability of MIC data is critical for situation analysis and monitoring trends in global antimicrobial analysis. Two hundred and forty eight clinical isolates of N. gonorrhoeae and the World Health Organisation (WHO) N. gonorrhoeae reference strains were tested using the three methods. When compared, CDS AD and CDS Etest gave a regression R(2) value of 94%, the Pearson's correlation coefficient was 97% and a paired comparison within one log2 dilution was 98%. The CDS AD and the Etest (CLSI) comparison gave a regression R(2) value of 90%, a Pearson's correlation coefficient of 95% and a paired comparison within one log2 dilution was 98%. The comparison of the CDS Etest and CLSI Etest gave a regression R(2) value of 91%, a Pearson's correlation coefficient of 95% and a paired comparison within one log2 dilution of 99%. Importantly, there was robust agreement between all three methods for the categorization of susceptibility of Neisseria gonorrhoeae isolates using the WHO nominated breakpoint for decreased susceptibility to ceftriaxone (≥0.125 μg/mL). The CDS Etest method is comparable to agar dilution and the Etest methods for determining the MIC of ceftriaxone against N. gonorrhoeae. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Comparison of two ultra-sensitive methods for the determination of 232Th by recovery corrected pre-concentration radiochemical neutron activation analysis

    International Nuclear Information System (INIS)

    Glover, S.E.; Qu, H.; LaMont, S.P.; Grimm, C.A.; Filby, R.H.

    2001-01-01

    The determination of isotopic thorium by alpha spectrometric methods is a routine practice for bioassay and environmental measurement programs. Alpha-spectrometry has excellent detection limits (by mass) for all isotopes of thorium except 232 Th due to its extremely long half-life. Improvements in the detection limit an sensitivity over previously reported methods of pre-concentration neutron activation analysis (PCNAA) for the recovery corrected, isotopic determination of thorium in various matrices is discussed. Following irradiation, the samples were dissolved, 231 Pa added as a tracer, and Pa isolated by two different methods and compared (extraction chromatography and anion exchange chromatography) followed by alpha spectrometry for recovery correction. Ion exchange chromatography was found to be superior for this application at this time, principally for reliability. The detection limit for 232 Th of 3.5 x 10 -7 Bq is almost three orders of magnitude lower than for alpha spectrometry using the PCRNAA method and one order of magnitude below previously reported PCNAA methods. (author)

  10. Development and Optimization of Voltammetric Methods for Real Time Analysis of Electrorefiner Salt with High Concentrations of Actinides and Fission Products

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, Michael F.; Phongikaroon, Supathorn; Zhang, Jinsuo

    2018-03-30

    This project addresses the problem of achieving accurate material control and accountability (MC&A) around pyroprocessing electrorefiner systems. Spent nuclear fuel pyroprocessing poses a unique challenge with respect to reprocessing technology in that the fuel is never fully dissolved in the process fluid. In this case, the process fluid is molten, anhydrous LiCl-KCl salt. Therefore, there is no traditional input accountability tank. However, electrorefiners (ER) accumulate very large quantities of fissile nuclear material (including plutonium) and should be well safeguarded in a commercial facility. Idaho National Laboratory (INL) currently operates a pyroprocessing facility for treatment of spent fuel from Experimental Breeder Reactor-II with two such ER systems. INL implements MC&A via a mass tracking model in combination with periodic sampling of the salt and other materials followed by destructive analysis. This approach is projected to be insufficient to meet international safeguards timeliness requirements. A real time or near real time monitoring method is, thus, direly needed to support commercialization of pyroprocessing. A variety of approaches to achieving real time monitoring for ER salt have been proposed and studied to date—including a potentiometric actinide sensor for concentration measurements, a double bubbler for salt depth and density measurements, and laser induced breakdown spectroscopy (LIBS) for concentration measurements. While each of these methods shows some promise, each also involves substantial technical complexity that may ultimately limit their implementation. Yet another alternative is voltammetry—a very simple method in theory that has previously been tested for this application to a limited extent. The equipment for a voltammetry system consists of off-the-shelf components (three electrodes and a potentiostat), which results in substantial benefits relative to cost and robustness. Based on prior knowledge of electrochemical

  11. Methods of DNA sequencing by hybridization based on optimizing concentration of matrix-bound oligonucleotide and device for carrying out same

    Science.gov (United States)

    Khrapko, Konstantin R.; Khorlin, Alexandr A.; Ivanov, Igor B.; Ershov, Gennady M.; Lysov, Jury P.; Florentiev, Vladimir L.; Mirzabekov, Andrei D.

    1996-09-03

    A method for sequencing DNA by hybridization that includes the following steps: forming an array of oligonucleotides at such concentrations that either ensure the same dissociation temperature for all fully complementary duplexes or allows hybridization and washing of such duplexes to be conducted at the same temperature; hybridizing said oligonucleotide array with labeled test DNA; washing in duplex dissociation conditions; identifying single-base substitutions in the test DNA by analyzing the distribution of the dissociation temperatures and reconstructing the DNA nucleotide sequence based on the above analysis. A device for carrying out the method comprises a solid substrate and a matrix rigidly bound to the substrate. The matrix contains the oligonucleotide array and consists of a multiplicity of gel portions. Each gel portion contains one oligonucleotide of desired length. The gel portions are separated from one another by interstices and have a thickness not exceeding 30 .mu.m.

  12. A machine learning method to estimate PM2.5 concentrations across China with remote sensing, meteorological and land use information.

    Science.gov (United States)

    Chen, Gongbo; Li, Shanshan; Knibbs, Luke D; Hamm, N A S; Cao, Wei; Li, Tiantian; Guo, Jianping; Ren, Hongyan; Abramson, Michael J; Guo, Yuming

    2018-04-24

    Machine learning algorithms have very high predictive ability. However, no study has used machine learning to estimate historical concentrations of PM 2.5 (particulate matter with aerodynamic diameter ≤ 2.5 μm) at daily time scale in China at a national level. To estimate daily concentrations of PM 2.5 across China during 2005-2016. Daily ground-level PM 2.5 data were obtained from 1479 stations across China during 2014-2016. Data on aerosol optical depth (AOD), meteorological conditions and other predictors were downloaded. A random forests model (non-parametric machine learning algorithms) and two traditional regression models were developed to estimate ground-level PM 2.5 concentrations. The best-fit model was then utilized to estimate the daily concentrations of PM 2.5 across China with a resolution of 0.1° (≈10 km) during 2005-2016. The daily random forests model showed much higher predictive accuracy than the other two traditional regression models, explaining the majority of spatial variability in daily PM 2.5 [10-fold cross-validation (CV) R 2  = 83%, root mean squared prediction error (RMSE) = 28.1 μg/m 3 ]. At the monthly and annual time-scale, the explained variability of average PM 2.5 increased up to 86% (RMSE = 10.7 μg/m 3 and 6.9 μg/m 3 , respectively). Taking advantage of a novel application of modeling framework and the most recent ground-level PM 2.5 observations, the machine learning method showed higher predictive ability than previous studies. Random forests approach can be used to estimate historical exposure to PM 2.5 in China with high accuracy. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Temporal changes in Hg, Pb, Cd and Zn environmental concentrations in the southern Baltic Sea sediments dated with 210Pb method

    Directory of Open Access Journals (Sweden)

    Tamara Zalewska

    2015-01-01

    Full Text Available The article presents data on heavy metal – Hg, Pb, Cd and Zn – distribution in the layers of marine sediments from the off-shore areas of the southern Baltic Sea: Gdańsk Deep, SE Gotland Basin and Bornholm Deep. Depth profiles of metal concentrations were converted to time-based profiles using the 210Pb dating method and verified by 137Cs distribution in the vertical profile. The linear sedimentation rates in the Gdańsk Deep and SE Gotland Basin are similar, 0.18 cm yr−1 and 0.14 cm yr−1, respectively, while the region of the Bornholm Deep is characterized by a greater sedimentation rate: 0.31 cm yr−1. Regarding anthropogenic pressure, Gdańsk Deep receives the largest share among the analyzed regions. The maximal metal concentrations detected in this area were Zn – 230 mg kg−1, Pb – 77 mg kg−1, Cd – 2.04 mg kg−1 and Hg – 0.27 mg kg−1. The least impact of anthropogenic pressure was noticeable in SE Gotland Basin. The combination of sediment dating with the analysis of vertical distribution of heavy metals in sediments benefited in the determination of target metal concentrations used in environmental status assessments. Reference values of heavy metal concentrations in marine sediments were determined as: Zn – 110 mg kg−1, Pb – 30 mg kg−1, Cd – 0.3 mg kg−1 and Hg – 0.05 mg kg−1 from the period of minor anthropogenic pressure. Basing on the determined indices: enrichment factor (EF, geoaccumulation indicator (Igeo and contamination factor (CF the status of marine environment was assessed regarding the pollution with heavy metals.

  14. A novel ion-exclusion chromatography-mass spectrometry method to measure concentrations and cycling rates of carbohydrates and amino sugars in freshwaters.

    Science.gov (United States)

    Horňák, Karel; Pernthaler, Jakob

    2014-10-24

    The concentrations of free neutral carbohydrates and amino sugars were determined in freshwater samples of distinct matrix complexity, including meso-, eu- and dystrophic lakes and ponds, using high-performance ion-exclusion chromatography (HPIEC) coupled to mass spectrometry (MS). In contrast to other methods, our approach allowed the quantification of free neutral carbohydrates and amino sugars at low nM concentrations without derivatization, de-salting or pre-concentration. New sample preparation procedures were applied prior to injection employing syringe and hollow fiber filtration. Analytes were separated on a strong cation exchange resin under 100% aqueous conditions using 0.1% formic acid as a mobile phase. To minimize background noise in MS, analytes were detected in a multiple reaction monitoring scan mode with double ion filtering. Detection limits of carbohydrates and amino sugars ranged between 0.2 and 2nM at a signal-to-noise ratio >5. Error ranged between 1 and 12% at 0.5-500nM levels. Using a stable isotope dilution approach, both the utilization and recycling of glucose in Lake Zurich was observed. In contrast, N-acetyl-glucosamine was equally rapidly consumed but there was no visible de novo production. The simple and rapid sample preparation makes our protocol suitable for routine analyses of organic compounds in freshwater samples. Application of stable isotope tracers along with accurate measures of carbohydrate and amino sugar concentrations enables novel insights into the compound in situ dynamics. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Novel Fluorometric Method for the Determination of Production Rate and Steady-State Concentration of Photochemically Generated Superoxide Radical in Seawater Using 3',6'-(Diphenylphosphinyl)fluorescein.

    Science.gov (United States)

    Anifowose, Adebanjo Jacob; Takeda, Kazuhiko; Sakugawa, Hiroshi

    2015-12-15

    Superoxide radical (O2(•-)) is an important reactive oxygen species in seawater. Measurements of its production rates and steady-state concentrations generated by photochemical processes have been a Herculean task over the years. In this study, a probe - 3'6'-(diphenylphosphinyl)fluorescein (PF-1) - was used to trap photochemically generated O2(•-) in seawater, thereby yielding fluorescein. The fluorescein produced was measured by an isocratic fluorescence HPLC at excitation/emission wavelengths of 490/513 nm, respectively. The reaction rate constant of PF-1 with O2(•-) (kPF-1) was pH-dependent: (3.2-23.5) × 10(7) M(-1) s(-1) at pHTOT 7.65-8.50. By applying appropriate equations, both the production rate and the steady-state concentration of O2(•-) generated by photochemical reactions in the seawater were quantified. Under the optimized experimental conditions, fluorescein standards (3-50 nM) exhibited linearity in the seawater by HPLC. The photoformation of fluorescein, due to the reaction of PF-1 with the O2(•-) photochemically produced in the seawater, was linear within the 20 min irradiation. The detection limit of the fluorescein photoformation rate was 0.03 pM s(-1), defined as 3σ of the lowest standard fluorescein concentration per 20 min irradiation. Using this value, the yield of fluorescein, and the fraction of O2(•-) that reacted with PF-1 in the seawater, the detection limit of the O2(•-) photoformation rate was 1.78 pM s(-1). Superoxide measurements using the proposed method were relatively unaffected by the potential interfering species in seawater. Application of the proposed method to ten (10) seawater samples from the Seto Inland Sea, Japan, resulted in measured O2(•-) photoformation rates of 3.1-8.5 nM s(-1), with steady-state concentrations ranging (0.06-0.3) × 10(-10) M. The method is simple, requires no technical sample preparation, and can be used to analyze a large number of samples.

  16. A new general method for simultaneous fitting of temperature and concentration dependence of reaction rates yields kinetic and thermodynamic parameters for HIV reverse transcriptase specificity.

    Science.gov (United States)

    Li, An; Ziehr, Jessica L; Johnson, Kenneth A

    2017-04-21

    Recent studies have demonstrated the dominant role of induced fit in enzyme specificity of HIV reverse transcriptase and many other enzymes. However, relevant thermodynamic parameters are lacking, and equilibrium thermodynamic methods are of no avail because the key parameters can only be determined by kinetic measurement. By modifying KinTek Explorer software, we present a new general method for globally fitting data collected over a range of substrate concentrations and temperatures and apply it to HIV reverse transcriptase. Fluorescence stopped-flow methods were used to record the kinetics of enzyme conformational changes that monitor nucleotide binding and incorporation. The nucleotide concentration dependence was measured at temperatures ranging from 5 to 37 °C, and the raw data were fit globally to derive a single set of rate constants at 37 °C and a set of activation enthalpy terms to account for the kinetics at all other temperatures. This comprehensive analysis afforded thermodynamic parameters for nucleotide binding ( K d , Δ G , Δ H , and Δ S at 37 °C) and kinetic parameters for enzyme conformational changes and chemistry (rate constants and activation enthalpy). Comparisons between wild-type enzyme and a mutant resistant to nucleoside analogs used to treat HIV infections reveal that the ground state binding is weaker and the activation enthalpy for the conformational change step is significantly larger for the mutant. Further studies to explore the structural underpinnings of the observed thermodynamics and kinetics of the conformational change step may help to design better analogs to treat HIV infections and other diseases. Our new method is generally applicable to enzyme and chemical kinetics. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Minimizing the creation of spent pickling liquors in a pickling process with high-concentration hydrochloric acid solutions: mechanism and evaluation method.

    Science.gov (United States)

    Tang, Bing; Su, Wen; Wang, Jing; Fu, Fenglian; Yu, Guojun; Zhang, Jianyin

    2012-05-15

    The purpose of this investigation is to propose a strategy for minimizing the creation of spent pickling liquors through the synergistic corrosion inhibition of OP-10 and potassium iodide, thus facilitating a cleaner production process for acid pickling of metals with a high-concentration solution (6.0 mol/l) of hydrochloric acid. Results obtained with the methods of weight loss and electrochemical polarization showed that adding KI and OP-10 could enhance the energy barrier of the corrosion reaction and improved the corrosion inhibition for mild steel in high concentration of HCl solutions. A synergistic effect was identified when KI and OP-10 were present in suitable proportions. The results of the electrochemical experiments and scanning electron microscope (SEM) observations showed that the complex inhibitor was a mixed-type inhibitor and it formed a compact film on the metal surface, thus providing an effective protection for the metal in the aggressive solutions, which significantly minimized the creation of spent pickling liquors. A simple and convenient method was also proposed for the quantificational evaluation of the inhibition degree in the creation of spent pickling liquors. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Feasibility Study on a Measurement Method and a Portable Measuring System to Estimate the Concentration of Cloxacillin and β-Lactamase in Milk

    Directory of Open Access Journals (Sweden)

    Luca Ferrari

    2017-01-01

    Full Text Available Antibiotics are nowadays used and abused worldwide in common veterinary practice to treat diseases, prevent infections, and promote animal’s growth. Drug resistance occurrence is a relevant phenomenon that can inactivate the antibiotic. Moreover, antibiotics used for animals are also found in milk and it poses serious health risks to humans. Another negative effect is related to milk processors since antibiotics cause detrimental effects on cheese and yogurt starter bacteria. Given its consumption as both beverage and derivatives, milk is one of the most regulated products in food industry. Nowadays several commercial tests are available to investigate antibiotics in milk, but they generally provide a qualitative result, require bulky procedure, and are time consuming. In this paper, we investigate the use of a chromogenic cephalosporin to quantify the concentration of cloxacillin—a β-lactam difficult to be detected by using “cowside” screenings which is the drug of choice in the method of mastitis control. The proposed measurement method and prototype have been demonstrated to be able to detect cloxacillin in milk at concentrations lower than the MRL set by the European Commission. Moreover, they are also able to detect the illegal practice of using β-lactamase to degrade β-lactams in milk.

  19. Effect of hydrofluoric acid concentration on the evolution of photoluminescence characteristics in porous silicon nanowires prepared by Ag-assisted electroless etching method

    KAUST Repository

    Najar, Adel

    2012-01-01

    We report on the structural and optical properties of porous silicon nanowires (PSiNWs) fabricated using silver (Ag) ions assisted electroless etching method. Silicon nanocrystallites with sizes <5 nm embedded in amorphous silica have been observed from PSiNW samples etched using the optimum hydrofluoric acid (HF) concentration. The strongest photoluminescence (PL) signal has been measured from samples etched with 4.8 M of HF, beyond which a significant decreasing in PL emission intensity has been observed. A qualitative model is proposed for the formation of PSiNWs in the presence of Ag catalyst. This model affirms our observations in PL enhancement for samples etched using HF <4.8 M and the eventual PL reduction for samples etched beyond 4.8 M of HF concentration. The enhancement in PL signals has been associated to the formation of PSiNWs and the quantum confinement effect in the Si nanocrystallites. Compared to PSiNWs without Si-O x, the HF treated samples exhibited significant blue PL peak shift of 100 nm. This effect has been correlated to the formation of defect states in the surface oxide. PSiNWs fabricated using the electroless etching method can find useful applications in optical sensors and as anti-reflection layer in silicon-based solar cells. © 2012 American Institute of Physics.

  20. Analysis of glycoprotein-derived oligosaccharides in glycoproteins detected on two-dimensional gel by capillary electrophoresis using on-line concentration method.

    Science.gov (United States)

    Kamoda, Satoru; Nakanishi, Yasuharu; Kinoshita, Mitsuhiro; Ishikawa, Rika; Kakehi, Kazuaki

    2006-02-17

    Capillary electrophoresis (CE) is an effective tool to analyze carbohydrate mixture derived from glycoproteins with high resolution. However, CE has a disadvantage that a few nanoliters of a sample solution are injected to a narrow capillary. Therefore, we have to prepare a sample solution of high concentration for CE analysis. In the present study, we applied head column field-amplified sample stacking method to the analysis of N-linked oligosaccharides derived from glycoprotein separated by two-dimensional gel electrophoresis. Model studies demonstrated that we achieved 60-360 times concentration effect on the analysis of carbohydrate chains labeled with 3-aminobenzoic acid (3-AA). The method was applied to the analysis of N-linked oligosaccharides from glycoproteins separated and detected on PAGE gel. Heterogeneity of alpha1-acid glycoprotein (AGP), i.e. glycoforms, was examined by 2D-PAGE and N-linked oligosaccharides were released by in-gel digestion with PNGase F. The released oligosaccharides were derivatized with 3-AA and analyzed by CE. The results showed that glycoforms having lower pI values contained a larger amount of tetra- and tri-antennary oligosaccharides. In contrast, glycoforms having higher pI values contained bi-antennary oligosaccharides abundantly. The result clearly indicated that the spot of a glycoprotein glycoform detected by Coomassie brilliant blue staining on 2D-PAGE gel is sufficient for quantitative profiling of oligosaccharides.

  1. Spectra and concentration profiles throughout the reaction of curing epoxy resins from near-infrared spectroscopy and multivariate curve resolution methods.

    Science.gov (United States)

    Larrechi, M S; Rius, F X

    2004-01-01

    When applied to near-infrared (NIR) data, multivariate curve resolution methods, in particular alternating least squares (ALS), make it possible to calculate the concentration profiles and the spectra of all species involved in the reaction of curing epoxy resins. In this paper, the model reaction between phenyl glicidyl ether and aniline (2:1) was studied at 95 degrees C. A NIR spectrum was recorded every five minutes throughout the eight-hour reaction process. The data display rank deficiency. This problem was overcome by supplying additional information to the system in the form of known spectra of some reactants. The recovered spectra and concentration profiles satisfactorily reproduced the experimental data. In this way, 99.99% of the variance associated with the experimental matrix was reproduced. A value of 0.87% was obtained for lack of fit while the similarity coefficient r between the spectra recovered and the spectra corresponding to the three pure species involved in the reaction were PGE (r = 0.994), aniline (r = 0.994), and tertiary amine (r = 0.999). The maximum and minimum limits associated with the ALS solutions were calculated, which made it possible to limit to a considerable extent the ambiguity that is characteristic of these curve resolution methods.

  2. A modified SINTACS method for groundwater vulnerability and pollution risk assessment in highly anthropized regions based on NO3-and SO42-concentrations.

    Science.gov (United States)

    Busico, Gianluigi; Kazakis, Nerantzis; Colombani, Nicolò; Mastrocicco, Micòl; Voudouris, Konstantinos; Tedesco, Dario

    2017-12-31

    Groundwater vulnerability and risk assessment are worldwide tools in supporting groundwater protection and land planning. In this study, we used three of these different methodologies applied to the Campanian Plain located in southern Italy: SINTACS, AVI and LOS. However, their capability to describe the observed chemical pollution of the area has resulted quite poor. For such a reason, a modified SINTACS method has been then implemented in the area in order to get a more reliable view of groundwater vulnerability. NO 3 - and SO 4 2- from more than 400 monitoring wells were used for specific vulnerability assessment. Land use was chosen as key parameter to infer the risk of groundwater pollution in our area. The new methodology seems to show a higher correlation with observed NO 3 - concentrations and a more reliable identification of aquifer's pollution hot spots. The main sources of NO 3 - were found in sub-urban areas, where vulnerability and risk are higher than in other areas. Otherwise due to reducing conditions triggered by the presence of elevated sedimentary organic matter and peat, concentrations below agricultural areas were lower than in sub-urban areas. The SO 4 2- specific vulnerability map showed a positive correlation with observed concentrations, due to geogenic and anthropogenic SO 4 2- sources present in the area. The combination of both NO 3 - and SO 4 2- derived risk maps becomes essential to improve the conceptual model of aquifer pollution in this severely anthropized area. The application of this new and original approach shed light on the strengths and weaknesses of each of the described previous methods and clearly showed how anthropogenic activities have to be taken into account in the assessment process. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Inability of Turbidimetry Method in Detecting Glycated Hemoglobin to Select Diabetes Mellitus Patients According to Their Concentrations of Blood Glucose Levels.

    Science.gov (United States)

    Abdallah, Alessandra M; Alves, Beatriz C A; Gehrke, Flávia S; Sant' Ana, Aleksandra V L; Azzalis, Ligia A; Junqueira, Virginia B C; Adami, Fernando; Pereira, Edimar C; Fonseca, Fernando L A

    2015-07-01

    Diabetes mellitus is a chronicle illness in which there is a high blood glucose level defined as hyperglycemia, resulted by a deficiency in insulin secretion and/or in its action. Nowadays, it is being seen as a public health problem and is reaching increasing proportions with regard to the appearance of new cases. For diagnosis, sensible and accurate methods should be used to avoid complications of the sickness. The measure of glycated hemoglobin may not be used for diagnosis, but is the reference method to evaluate the grade of glycemic control in the long term, reflecting the blood glucose level in the latest 2-3 months. The aim of this study was to evaluate the grade of concordance between turbidimetry and liquid chromatography methods in the glycated hemoglobin determination and to estimate the sensibility and specificity values of turbidimetry. This study included 133 blood samples obtained from patients and healthy donors, ageing between 18 and 80 years with glycemic values between 58 and 473 mg/dl. Turbidimetry is a useful method for determining glycemic levels above 100 and over 200 mg/dl, but does not have the ability to select samples with intermediary blood glucose concentrations. © 2014 Wiley Periodicals, Inc.

  4. Influence of different susceptibility testing methods and media on determination of the relevant fluconazole minimum inhibitory concentrations for heavy trailing Candida isolates with low-high phenotype.

    Science.gov (United States)

    Alp, Sehnaz; Sancak, Banu; Hascelik, Gulsen; Arikan, Sevtap

    2010-11-01

    We investigated the incidence of trailing growth with fluconazole in 101 clinical Candida isolates (49 C. albicans and 52 C. tropicalis) and tried to establish the convenient susceptibility testing method and medium for fluconazole minimum inhibitory concentration (MIC) determination. MICs were determined by CLSI M27-A2 broth microdilution (BMD) and Etest methods on RPMI-1640 agar supplemented with 2% glucose (RPG) and on Mueller-Hinton agar supplemented with 2% glucose and 0.5 μg ml(-1) methylene blue (GMB). BMD and Etest MICs were read at 24 and 48 h, and susceptibility categories were compared. All isolates were determined as susceptible with BMD, Etest-RPG and Etest-GMB at 24 h. While all isolates were interpreted as susceptible at 48 h on Etest-RPG and Etest-GMB, one C. albicans isolate was interpreted as susceptible-dose dependent (S-DD) and two C. tropicalis isolates were interpreted as resistant with BMD. On Etest-RPG, trailing growth caused widespread microcolonies within the inhibition zone and resulted in confusion in MIC determination. On Etest-GMB, because of the nearly absence of microcolonies within the zone of inhibition, MICs were evaluated more easily. We conclude that, for the determination of fluconazole MICs of trailing Candida isolates, the Etest method has an advantage over BMD and can be used along with this reference method. Moreover, GMB appears more beneficial than RPG for the fluconazole Etest. © 2009 Blackwell Verlag GmbH.

  5. Device and method for the concentration of solar rays with automatic tracking of the sun. Procede et dispositif pour la concentration du rayonnement solaire avec la poursuite automatique du soleil

    Energy Technology Data Exchange (ETDEWEB)

    Barski, V.Z.

    1991-07-03

    In a high efficiency process and apparatus for concentrating solar radiation, the concentrator is equipped with an automatic solar tracking system. According to the invention, the mirror assembly is located on the interior of a spherical concentrator turning around its geometric center, in which a heat exchanger is placed. The concentrator includes an electrohydraulic control system, with periodically variable stepping servomotors fed by a source of pressurized liquid, or an electric control system having reversible electric motors. The heat exchanger can be connected with energy receiving devices, such as heating installations or heat engines, by means of well-insulated fixed piping. 5 figs.

  6. Validation of GOSAT XCO2 and XCH4 retrieved by PPDF-S method and evaluation of sensitivity of aerosols to gas concentrations

    Science.gov (United States)

    Iwasaki, C.; Imasu, R.; Bril, A.; Yokota, T.; Yoshida, Y.; Morino, I.; Oshchepkov, S.; Rokotyan, N.; Zakharov, V.; Gribanov, K.

    2017-12-01

    Photon path length probability density function-Simultaneous (PPDF-S) method is one of effective algorithms for retrieving column-averaged concentrations of carbon dioxide (XCO2) and methane (XCH4) from Greenhouse gases Observing SATellite (GOSAT) spectra in Short Wavelength InfraRed (SWIR) [Oshchepkov et al., 2013]. In this study, we validated XCO2 and XCH4 retrieved by the PPDF-S method through comparison with the Total Carbon Column Observing Network (TCCON) data [Wunch et al., 2011] from 26 sites including additional site of the Ural Atmospheric Station at Kourovka [57.038°N and 59.545°E], Russia. Validation results using TCCON data show that bias and its standard deviation of PPDF-S data are respectively 0.48 and 2.10 ppm for XCO2, and -0.73 and 15.77 ppb for XCH4. The results for XCO2 are almost identical with those of Iwasaki et al. [2017] for which the validation data were limited at selected 11 sites. However, the bias of XCH4 shows opposite sign against that of Iwasaki et al. [2017]. Furthermore, the data at Kourouvka showed different features particularly for XCH4. In order to investigate the causes for the differences, we have carried out simulation studies mainly focusing on the effects of aerosols which modify the light path length of solar radiation [O'Brien and Rayner, 2002; Aben et al., 2007; Oshchepkov et al., 2008]. Based on the simulation studies using multiple radiation transfer code based on Discrete Ordinate Method (DOM), Polarization System for Transfer of Atmospheric Radiation3 (Pstar3) [Ota et al., 2010], sensitivity of aerosols to gas concentrations was examined.

  7. Concentration risk

    Directory of Open Access Journals (Sweden)

    Matić Vesna

    2016-01-01

    Full Text Available Concentration risk has been gaining a special dimension in the contemporary financial and economic environment. Financial institutions are exposed to this risk mainly in the field of lending, mostly through their credit activities and concentration of credit portfolios. This refers to the concentration of different exposures within a single risk category (credit risk, market risk, operational risk, liquidity risk.

  8. Use of (1-3)-beta-d-glucan concentrations in dust as a surrogate method for estimating specific fungal exposures.

    Science.gov (United States)

    Iossifova, Y; Reponen, T; Sucharew, H; Succop, P; Vesper, S

    2008-06-01

    Indoor exposure to fungi has been associated with respiratory symptoms,often attributed to their cell wall component, (1-3)-beta-D-glucan. Performing(1-3)-beta-D-glucan analysis is less time consuming and labor intensive than cultivation or microscopic counting of fungal spores. This has prompted many to use(1-3)-beta-D-glucan as a surrogate for fungal exposure. The aim of this study was to examine which indoor fungal species are major contributors to the (1-3)-beta-D-glucan concentration in field dust samples. We used the quantitative polymerase chain reaction (QPCR) method to analyze 36 indoor fungal species in 297 indoor dust samples. These samples were also simultaneously analyzed for (1-3)-beta-D-glucan concentration using the endpoint chromogenic Limulus Amebocyte lysate assay. Linear regression analysis, followed by factor analysis and structural equation modeling, were utilized in order to identify fungal species that mostly contribute to the (1-3)-beta-D-glucan concentration in field dust samples. The study revealed that Cladosporium and Aspergillus genera, as well as Epicoccum nigrum, Penicillium brevicompactum and Wallemia sebi were the most important contributors to the (1-3)-beta-D-glucan content of these home dust samples. The species that contributed most to the (1-3)-beta-D-glucan concentration were also the most prevalent in indoor environments. However, Alternaria alternata, a common fungal species in indoor dust, did not seem to be a significant source of (1-3)-beta-D-glucan. This study revealed that the (1-3)-beta-D-glucan content of different fungal species varies widely. (1-3)-beta-D-glucan inhouse dust from the Greater Cincinnati area may be a good marker for some fungal species of the Cladosporium and Aspergillus genera. In contrast, Alternaria alternata did not contribute much to the (1-3)-beta-D-glucan load. Therefore, (1-3)-beta-D-glucan concentration in field samples as a surrogate for total fungal exposure should be used with caution.

  9. Concentrator Photovoltaics

    CERN Document Server

    Luque, Antonio L

    2007-01-01

    Photovoltaic solar-energy conversion is one of the most promising technologies for generating renewable energy, and conversion of concentrated sunlight can lead to reduced cost for solar electricity. In fact, photovoltaic conversion of concentrated sunlight insures an efficient and cost-effective sustainable power resource. This book gives an overview of all components, e.g. cells, concentrators, modules and systems, for systems of concentrator photovoltaics. The authors report on significant results related to design, technology, and applications, and also cover the fundamental physics and market considerations. Specific contributions include: theory and practice of sunlight concentrators; an overview of concentrator PV activities; a description of concentrator solar cells; design and technology of modules and systems; manufacturing aspects; and a market study.

  10. Erythrocyte sedimentation rate and fibrinogen concentration of whole blood influences the cellular composition of platelet-rich plasma obtained from centrifugation methods.

    Science.gov (United States)

    Yin, Wenjing; Xu, Zhengliang; Sheng, Jiagen; Xie, Xuetao; Zhang, Changqing

    2017-09-01

    Erythrocyte sedimentation rate (ESR), which reflects the sedimentation rate of platelets, leukocytes and erythrocytes in response to centrifugal force, may influence the cellular composition of platelet-rich plasma (PRP) obtained via centrifugation methods. However, no relevant studies have substantiated this. In the present study, blood was collected from 40 healthy volunteers and used to prepare PRP with two plasma-based preparation systems [YinPRP and Plasma Rich in Growth Factor (PRGF) systems] and two buffy coat-based systems (RegenPRP and WEGOPRP systems) in a single-donor model. Volumes of PRP and platelet-poor plasma (PPP) that were removed in the preparation process were recorded. Analyses of ESR, haematocrit, C-reaction protein, coagulation, serum glucose and serum lipid of the whole blood used for PRP preparation were performed to evaluate the levels of ESR and the factors known to influence it. Whole blood analysis was performed to evaluate the cellular composition of PRP. Results demonstrated that there were marked positive correlations between the ESR of the whole blood used for PRP preparation and PPP removal efficiencies, platelet concentrations, platelet capture efficiencies and platelet enrichment factors of PRP formulations obtained from plasma-based systems, and PRP yield efficiency of RegenPRP and PPP removal efficiency of WEGOPRP. Furthermore, there were marked negative correlations between ESR and concentrations and enrichment factors of platelets, leukocytes and erythrocytes of RegenPRP. Fibrinogen concentration of the whole blood, which had a marked positive correlation with ESR, also influenced the cellular composition of PRP. These findings may increase the understanding of PRP preparation and provide substantial evidence for the individualised optimisation of PRP preparation systems used in clinical practice.

  11. Method development for the concentration determination of a protein in human plasma utilizing 96-well solid-phase extraction and liquid chromatography/tandem mass spectrometric detection.

    Science.gov (United States)

    Ji, Qin C; Gage, Eric M; Rodila, Ramona; Chang, Min S; El-Shourbagy, Tawakol A

    2003-01-01

    Although liquid chromatography/tandem mass spectrometry (LC/MS/MS) technology has been widely used for quantitative analysis of small organic molecules, it has been a challenging task to quantitatively analyze protein samples utilizing this technology in biological matrices for pre-clinical and clinical studies. Here we present our initial results in method development for the quantitative determination of rK5 protein concentrations in human plasma samples utilizing LC/MS/MS technology. A protein similar in structure to rK5, but with a slightly reduced molecular weight, was used as internal standard. A 96-well solid-phase extraction procedure was developed to effectively extract protein analytes from plasma samples. Quantitative analysis was obtained by a novel approach of protein monitoring that employed selective reaction monitoring (SRM). Even though mass spectrometry of the internal standard protein gave no fragment ions, SRM monitoring greatly reduced background interference. Using samples prepared in human plasma with sodium EDTA as anticoagulant, a correlation coefficient (r(2)) of 0.9940 was obtained by producing a single standard curve with the injection of six rows of standards with a concentration range from 100 ng/mL to 10 microg/mL. The mean analytical recovery for these standards ranged from 91.5 to 103.6%. The CVs for individual standard levels ranged from 3.7 to 20.9%. The experiment was also repeated using samples prepared in human plasma with sodium heparin as anticoagulant, which produced a correlation coefficient (r(2)) of 0.9952 obtained from a single standard curve with the injection of four rows of standards with a concentration range from 50 ng/mL to 10 microg/mL. The mean analytical recovery for the standards ranged from 96.2 to 104.6%. The CVs for individual standard levels ranged from 2.6 to 15.6%. Copyright 2003 John Wiley & Sons, Ltd.

  12. The efficiency of cross-linking methods in eradication of bacteria is influenced by the riboflavin concentration and the irradiation time of ultraviolet light.

    Science.gov (United States)

    Bäckman, Anders; Makdoumi, Karim; Mortensen, Jes; Crafoord, Sven

    2014-11-01

    To determine bacterial eradication using numerous riboflavin concentrations and different ultraviolet light A (UVA) radiant and exposure time in an experimental model. Dilutions of Staphylococcus epidermidis were mixed with riboflavin at varying concentrations (0.007–0.09%). Effects on bacterial growth were evaluated after 0, 3, 6, 30 and 60 min of UVA exposure (irradiance 30 and 3 mW/cm2). Standard settings of UVA were compared with high-power UVA approach. Different fluid thicknesses of the exposed dilutions were also examined to improve the model. Bacterial eradication (%) was increased after 60 compared with 30 min of UVA exposure for concentrations of 0.03–0.07% but not for 0.09% riboflavin.There was a significant difference between the efficacy between 0.03 and 0.09% and eradication dropped from 80%to 50%(p = 0.01).A correlation could be calculated for the amount of riboflavin at 60 min of UVA and the ability to kill bacteria(p = 0.01). The antibacterial effect was more pronounced when the tested bacterial suspension thickness was reduced. High-power UVA method was less potent in microbial elimination, eradicating only 60%of bacteria after 6 min versus 97–99%after 60 min in the low-power setting, compared with respective controls (p = 0.02). In these in vitro experiments, a longer UVA exposure time in combination with lower riboflavin levels were found to be favourable in killing bacteria as compared to the standard cross-linking settings. Further studies are needed to evaluate the clinical relevance of these findings.

  13. An ultrasound-assisted digestion method for the determination of toxic element concentrations in ash samples by inductively coupled plasma optical emission spectrometry

    International Nuclear Information System (INIS)

    Ilander, Aki; Vaeisaenen, Ari

    2007-01-01

    A method of ultrasound-assisted digestion followed by inductively coupled plasma optical emission spectrometry (ICP-OES) used for the determination of toxic element concentrations (arsenic, barium, cobalt, copper, lead, nickel, strontium, vanadium and zinc) in ash samples was developed. All the measurements were performed in robust plasma conditions which were tested by measuring the Mg(II) 280.270 nm/Mg(I) 285.213 nm line intensity ratios. The highest line intensity ratios were observed when a nebulizer gas flow of 0.6 L min -1 , auxiliary gas flow of 0.2 L min -1 and plasma power of 1400 W were used for radially viewed plasma. The analysis of SRM 1633b showed that the ultrasound-assisted method developed is highly comparable with the microwave digestion method standardized by the United States Environmental Protection Agency (EPA-3052). The ultrasound-assisted digestion with a digestion solution of aqua regia and hydrofluoric acid (HF) resulted in recovery rates of over 81%. One exception is arsenic which resulted in recoveries of about 60% only; however, it could be digested with good recovery (>90%) using a digestion solution of 5 mL of water and 5 mL of aqua regia. The major advantage of the ultrasound-assisted digestion over microwave digestion is the high treatment rate (30 samples simultaneously with a sonication time of 18 min)

  14. Co/Ti co-substituted layered LiNiO2 prepared using a concentration gradient method as an effective cathode material for Li-ion batteries

    Science.gov (United States)

    Ko, Hyoung Shin; Kim, Jea Han; Wang, Juan; Lee, Jong Dae

    2017-12-01

    The design of Li-ion batteries with high energy storage capacities and efficiencies is a subject of increased research interest, being of key importance for their large-scale applications and further commercialization. However, conventional Li-ion batteries are expensive and have stability-related concerns, which limit their practical applications. In our search for cheaper and safer Li-ion batteries, we use a concentration gradient method to prepare LiNi0.9Co0.1-xTixO2 (0.02 ≤ x ≤ 0.05) cathode materials surface-enriched with Co and Ti that exhibit decreased oxygen loss and improved structural stability. The corresponding crystal structures and morphologies are analyzed by X-ray diffraction and field emission scanning electron microscopy, with the Ni, Co, and Ti concentration distributions determined by energy-dispersive X-ray spectroscopy. The material with the best performance (x = 0.04) exhibits a discharge capacity of 214 mAh g-1 in a charge/discharge voltage range of 3.0-4.3 V (vs. Li/Li+), and possesses an excellent 50-cycle capacity retention of 98.7%. Thermogravimetric analysis shows that partial substitution of Ni with the strongly oxophilic Ti solves the problem of oxygen loss observed in Ni-rich cathode materials such as LiNiO2.

  15. Novel method to assessing and the impact of alpha emitter's concentration of the uterus on women fertility in Iraqi Kurdistan region

    International Nuclear Information System (INIS)

    Salih, N.F.; Jaafar, M.S.

    2013-01-01

    In the present work, 30 uterine tissue samples were collected from women with uterine problems from Iraqi Kurdistan. Tissue samples were analyzed and examined to measure levels of concentrated α-particle emitters and their short-lived decay products using a plastic track detector (CR-39) and the PVC long-tube technique with standard source radium ( 226 Ra). A new method and apparatus for the passive sampling of α-particles were also introduced. The maximum 0.0691 ppm and minimum 0.0180 ppm concentrations of particles were found in Sedakan and in Dukan, respectively; the average value was 0.0330 ppm, when compared the result with the result (0.12 ppm) in Asumadu-Sakyi et al. (Res J Environ Earth Sci 3(1):24-31, 2011) is lower than it and is agree with the result in Rubyie (Radioactive detection on the blood samples of cancer patients diseases by using CR-39 detector and its effect on cytogenetic. MSc. thesis, Al-Nahrain University, 2007). Also the results of fresh uterus are Significant (p 222 Rn gas varied from one woman to another depending on her age, the allergic reaction of her uterus to the radiation, and the geological formation of the area under study. The hazardous effects of α-particles are caused by increasing levels of ionizing radiation in the environment. (author)

  16. Effect of zinc concentration on the structural and magnetic properties of mixed Co–Zn ferrites nanoparticles synthesized by sol/gel method

    Energy Technology Data Exchange (ETDEWEB)

    Ben Ali, M., E-mail: m.benali06@gmail.com [MAScIR Foundation, Institute of Nanomaterials and Nanotechnologies, Materials & Nanomaterials Center, B.P., 10100 Rabat (Morocco); Laboratory of Magnetism and the Physics of the high Energies, URAC 12, Department of Physics, B.P. 1014, Faculty of Science, Mohammed V University, Rabat (Morocco); El Maalam, K. [MAScIR Foundation, Institute of Nanomaterials and Nanotechnologies, Materials & Nanomaterials Center, B.P., 10100 Rabat (Morocco); Laboratory of Magnetism and the Physics of the high Energies, URAC 12, Department of Physics, B.P. 1014, Faculty of Science, Mohammed V University, Rabat (Morocco); El Moussaoui, H.; Mounkachi, O. [MAScIR Foundation, Institute of Nanomaterials and Nanotechnologies, Materials & Nanomaterials Center, B.P., 10100 Rabat (Morocco); Hamedoun, M., E-mail: m.hamedoun@mascir.com [MAScIR Foundation, Institute of Nanomaterials and Nanotechnologies, Materials & Nanomaterials Center, B.P., 10100 Rabat (Morocco); Masrour, R. [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, PB 63 46000, Safi (Morocco); Hlil, E.K. [Institut Néel, CNRS-UJF, B.P. 166, 38042 Grenoble Cedex (France); Benyoussef, A. [MAScIR Foundation, Institute of Nanomaterials and Nanotechnologies, Materials & Nanomaterials Center, B.P., 10100 Rabat (Morocco); Laboratory of Magnetism and the Physics of the high Energies, URAC 12, Department of Physics, B.P. 1014, Faculty of Science, Mohammed V University, Rabat (Morocco)

    2016-01-15

    Synthesization of zinc-substituted cobalt ferrites nano-particles Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0.0–0.3) has been achieved by the sol/gel method. The characterization of the synthesized nano-particles has been done by X-ray diffractometry (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FITR). The relation between the composition and magnetic properties has been investigated by Magnetic Properties Measurement System (MPMS). The results revealed that the nanoparticles size is in the range of 11–28 nm. It was found that the zinc substitution in cobalt ferrite increases saturation magnetization from 60.92 emu/g (x=0) to 74.67 emu/g (x=0.3). Nevertheless, zinc concentrations cause a significant decrease in coercivity.▪ - Highlights: • The nanocrystals size of synthesized of Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} is of 11–28 nm. • The zinc substitution in cobalt ferrite increase saturation magnetization. • The increase of zinc concentration causes a significant decrease in coercivity.

  17. Effect of zinc concentration on the structural and magnetic properties of mixed Co–Zn ferrites nanoparticles synthesized by sol/gel method

    International Nuclear Information System (INIS)

    Ben Ali, M.; El Maalam, K.; El Moussaoui, H.; Mounkachi, O.; Hamedoun, M.; Masrour, R.; Hlil, E.K.; Benyoussef, A.

    2016-01-01

    Synthesization of zinc-substituted cobalt ferrites nano-particles Co 1−x Zn x Fe 2 O 4 (x=0.0–0.3) has been achieved by the sol/gel method. The characterization of the synthesized nano-particles has been done by X-ray diffractometry (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FITR). The relation between the composition and magnetic properties has been investigated by Magnetic Properties Measurement System (MPMS). The results revealed that the nanoparticles size is in the range of 11–28 nm. It was found that the zinc substitution in cobalt ferrite increases saturation magnetization from 60.92 emu/g (x=0) to 74.67 emu/g (x=0.3). Nevertheless, zinc concentrations cause a significant decrease in coercivity.▪ - Highlights: • The nanocrystals size of synthesized of Co 1−x Zn x Fe 2 O 4 is of 11–28 nm. • The zinc substitution in cobalt ferrite increase saturation magnetization. • The increase of zinc concentration causes a significant decrease in coercivity.

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

    Science.gov (United States)

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

    2008-07-01

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

  19. Changes in the chemical state and concentration of iron in carbon nanotubes obtained by the CVD method and exposed to pulsed ion irradiation

    Science.gov (United States)

    Korusenko, P. M.; Nesov, S. N.; Bolotov, V. V.; Povoroznyuk, S. N.; Pushkarev, A. I.; Knyazev, E. V.

    2017-10-01

    Data on the distribution of iron in nitrogen-containing multiwall carbon nanotubes (N-MWCNTs) and changes in its chemical state and concentration under different parameters of irradiation by a pulsed ion beam are obtained by methods of transmission electron microscopy, X-ray photoelectron spectroscopy, and energy dispersion analysis. It is shown that the irradiation of N-MWCNTs with an energy density of 0.5 J/cm2 lead to the formation, on their lateral surfaces, of structures with a size of 2-10 nm, consisting of metallic iron encapsulated in a carbon shell. An increase in the energy density to 1-1.5 J/cm2 leads to a substantial removal of iron clusters from the tips of carbon nanotubes and a reduction in the amount of iron in the bulk of the N-MWCNT layer.

  20. Acetylene Black/Sulfur Composites Synthesized by a Solution Evaporation Concentration Crystallization Method and Their Electrochemical Properties for Li/S Batteries

    Directory of Open Access Journals (Sweden)

    Zhigao Yang

    2013-07-01

    Full Text Available A novel technique to prepare carbon/sulfur composites as cathode materials for Li/S batteries is proposed, which we call the ‘solution evaporation concentration crystallization’ method. Three composites with different S loadings were prepared, subject to two different solvent evaporation rates from acetylene black (AB/sulfur in carbon disulfide solutions. X-ray diffraction, environmental scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller measurements all show that the porous AB structure is well-filled with S. Composites prepared at a lower solvent evaporation rate with 50 wt % S content, had good electrochemical properties, with 1609.67 mAh g−1 after 100 cycles. Composites with better dispersibility at a low solvent evaporation rate can effectively prevent polysulfide from dissolving in the electrolyte, and serve to stabilize the structure of the S cathode during the charge-discharge process.

  1. Concentration-dependent optical properties of TGA stabilized CdTe Quantum dots synthesized via the single injection hydrothermal method in the ambient environment

    Science.gov (United States)

    Jai Kumar, B.; Mahesh, H. M.

    2017-04-01

    Thioglycolic acid (TGA) stabilized aqueous CdTe Quantum dots (QDs) were synthesized using a facile, cost efficient Single Injection Hydrothermal (SIH) method. The complete preparation of precursors and growth of QDs was carried out in the ambient environment without inter gas protection. The Cadmium and Tellurium precursors were prepared from cadmium nitrate and elemental tellurium powder with sodium borohydride as reducing agent respectively. A systematic investigation was carried out in order to study the effect of 0.04M and 0.08M TGA concentration on ease synthesis, stability and size-tunable optical absorbance, bandgap, photoluminescence (PL) and Quantum yield (QY) of CdTe QDs. The Structure of QDs was verified by XRD and optical properties by absorbance and PL spectra. Experimental results revealed that the 0.08M TGA QDs possess good chemical and optical stability with high luminescence and decent QY, ready to use in optoelectronics, photovoltaic and biological application.

  2. Systemic Approach for Health Risk Assessment of Ambient Air Concentrations of Benzene in Petrochemical Environments: Integration of Fuzzy Logic, Artificial Neural Network, and IRIS Toxicity Method.

    Science.gov (United States)

    Novin, Vahid; Givehchi, Saeed; Hoveidi, Hassan

    2016-09-01

    Reliable methods are crucial to cope with uncertainties in the risk analysis process. The aim of this study is to develop an integrated approach to assessing risks of benzene in the petrochemical plant that produces benzene. We offer an integrated system to contribute imprecise variables into the health risk calculation. The project was conducted in Asaluyeh, southern Iran during the years from 2013 to 2014. Integrated method includes fuzzy logic and artificial neural networks. Each technique had specific computational properties. Fuzzy logic was used for estimation of absorption rate. Artificial neural networks can decrease the noise of the data so applied for prediction of benzene concentration. First, the actual exposure was calculated then it combined with Integrated Risk Information System (IRIS) toxicity factors to assess real health risks. High correlation between the measured and predicted benzene concentration was achieved (R 2 = 0.941). As for variable distribution, the best estimation of risk in a population implied 33% of workers exposed less than 1×10 -5 and 67% inserted between 1.0×10 -5 to 9.8×10 -5 risk levels. The average estimated risk of exposure to benzene for entire work zones is equal to 2.4×10 -5 , ranging from 1.5×10 -6 to 6.9×10 -5 . The integrated model is highly flexible as well as the rules possibly will be changed according to the necessities of the user in a different circumstance. The measured exposures can be duplicated well through proposed model and realistic risk assessment data will be produced.

  3. Reproducible measurement of vancomycin MICs within the susceptible range in Staphylococcus aureus by a broth microdilution method with a "quasi-continuum" gradient of antibiotic concentrations.

    Science.gov (United States)

    Falcón, R; Mateo, E M; Talaya, A; Giménez, E; Vinuesa, V; Clari, M Á; Navarro, D

    2017-12-01

    The availability of reproducible broth microdilution (BMD) methods including inter log 2 antibiotic dilutions for measuring Staphylococcus aureus (SA) vancomycin minimum inhibitory concentrations (MICs) within the susceptible range is needed to elucidate the impact of vancomycin MICs on clinical outcomes of invasive SA infections. Here, we report on the development of a very precise BMD method that incorporates the following incremental antibiotic concentrations: 0.50, 0.62, 0.75, 0.87, 1.0, 1.25, 1.40, 1.50, 1.60, 1.75, and 2.0 μg/mL. The intra- and inter-assay coefficients of variation of this method were around 20%. The mean of the differences in MIC values for all isolates obtained across two independent runs performed at one center was 0.04 μg/mL [95% confidence interval (CI), 0.011-0.07 μg/mL] and that for ten isolates measured at two different centers was 0.04 μg/mL (95% CI, 0-13 μg/mL). Vancomycin MIC values differed by less than 0.1 μg/mL between runs for most isolates. Storage of isolates at -20 °C for up to 3 months had no impact on the vancomycin MIC values. The mean vancomycin MIC values obtained by the Etest using a standard inoculum (0.5 McFarland) were significantly higher (p ≤ 0.001) than those measured by BMD and the MIC values measured by the two methods correlated poorly (Rho, 0.319; p = 0.148). Nevertheless, the mean MIC values measured by the Etest using lower inocula (10 7 or 10 6  CFU/mL) and those measured by BMD were comparable and correlated significantly (p = 0.004 for 10 7  CFU/mL and p = 0.029 for 10 6  CFU/mL).

  4. An empirical method for determination of elemental components of radiated powers and impurity concentrations from VUV and XUV spectral features in tokamak plasmas

    International Nuclear Information System (INIS)

    Lawson, K.; Peacock, N.; Gianella, R.

    1998-12-01

    The derivation of elemental components of radiated powers and impurity concentrations in bulk tokamak plasmas is complex, often requiring a full description of the impurity transport. A novel, empirical method, the Line Intensity Normalization Technique (LINT) has been developed on the JET (Joint European Torus) tokamak to provide routine information about the impurity content of the plasma and elemental components of radiated power (P rad ). The technique employs a few VUV and XUV resonance line intensities to represent the intrinsic impurity elements in the plasma. From a data base comprising these spectral features, the total bolometric measurement of the radiated power and the Z eff measured by visible spectroscopy, separate elemental components of P rad and Z eff are derived. The method, which converts local spectroscopic signals into global plasma parameters, has the advantage of simplicity, allowing large numbers of pulses to be processed, and, in many operational modes of JET, is found to be both reliable and accurate. It relies on normalizing the line intensities to the absolute calibration of the bolometers and visible spectrometers, using coefficients independent of density and temperature. Accuracies of the order of ± 15% can be achieved for the elemental P rad components of the most significant impurities and the impurity concentrations can be determined to within ±30%. Trace elements can be monitored, although with reduced accuracy. The present paper deals with limiter discharges, which have been the main application to date. As a check on the technique and to demonstrate the value of the LINT results, they have been applied to the transport modelling of intrinsic impurities carried out with the SANCO transport code, which uses atomic data from ADAS. The simulations provide independent confirmation of the concentrations empirically derived using the LINT technique. For this analysis, the simple case of the L-mode regime is considered, the chosen

  5. Comparison between the antimicrobial susceptibility of Burkholderia pseudomallei to trimethoprim-sulfamethoxazole by standard disk diffusion method and by minimal inhibitory concentration determination.

    Science.gov (United States)

    Lumbiganon, P; Tattawasatra, U; Chetchotisakd, P; Wongratanacheewin, S; Thinkhamrop, B

    2000-08-01

    Melioidosis, an infection caused by Burkholderia pseudomallei, usually occurs in immunocompromised patients and requires prolonged antibiotic therapy. Previously, oral trimethoprim-sulfamethoxazole (TM/SM), an inexpensive and effective drug has been used as a maintenance therapy. The susceptibility of B. pseudomallei to TM/SM by the standard disk diffusion method is very low. However, some patients who were treated with TM/SM as a maintenance therapy despite the in vitro resistance showed good clinical responses. There were no data comparing the susceptibility of B. pseudomallei by the standard disk diffusion method with other quantitative susceptibility tests. The objective of this study was to determine the agreement between the antimicrobial susceptibility of B. pseudomallei to TM/SM by standard disk diffusion and minimal inhibitory concentration determination (MIC). We performed the susceptibility test of 144 strains of B. pseudomallei to TM/SM by both the standard disk diffusion and microbroth dilution MIC. The sensitivity results were 53.5 per cent and 84.0 per cent respectively. The agreement between the 2 tests was very poor (Kappa = 0.14; 95% CI = -0.01 to 0.29). The false resistant rate by the standard disk diffusion test was 67.9 per cent. Further in vitro susceptibility and clinical study are needed to define the interpretive criteria that correlate with clinical response.

  6. A Subspace-Based Compensation Method for the Mutual Coupling in Concentric Circular Ring Arrays for Near-Field Source Localisation

    Directory of Open Access Journals (Sweden)

    Mohammed Jainul Abedin

    2012-01-01

    Full Text Available We propose a technique for compensating the effect of mutual coupling on parameter estimation that is suitable with any subspace-based super-resolution algorithms. A Concentric circular ring array (CCRA formed using thin dipole antennas in the receiving mode is employed to estimate the parameters of electromagnetic sources located in the radiating near field of the array. A CCRA geometry that obtains a lowest Cramer-Rao lower bound (CRLB in the presence of array mutual coupling is chosen for investigation. The mutual coupling among antenna elements of the array would affect the orthogonality of subspaces when MUSIC or ESPRIT algorithms are used for parameter estimation. The proposed method obtains a compensation matrix that restores the orthogonality between the subspaces there by improving the accuracy of estimation. To avoid three-dimensional searches, the range parameter is estimated using a cross-correlation-based method. Numerical simulation using a full-wave electromagnetic (EM solver is employed to demonstrate the effectiveness of the proposed compensation approach.

  7. Application of an improved biuret method to the determination of total protein in urine and cerebrospinal fluid without concentration step by use of Hitachi 7170 auto-analyzer.

    Science.gov (United States)

    Guobing, X; Lili, J; Lihua, Z; Tiean, X

    2001-01-01

    A biuret automated colorimetric assay for total protein in urine and cerebrospinal fluids was established. The procedures were as follows. Acidify all urine sample before analysis. Add precipitant Na(2)WO(4) to urine samples. After 10 min, centrifuge, decant the supernatant fluid, drain the inverted tubes on absorbent tissue, dissolve the precipitation with 0.1 mol/L NaOH, and finally adapt the reconstituted urine to the Hitachi 7170 analyzer. A cell-free cerebrospinal fluid sample produced by centrifugation can be inserted in an auto-analyzer for protein measurement directly. The program: mix 35 microl sample (CSF or reconstituted urine) and standard with 0.2 mol/L NaOH; incurable at 37 degrees C for 5 min, and real A1. Add concentrated biuret reagent, and 10 min later measure absorbance A2 at 546 nm vs. reagent blank. Secondary wavelength was 700 nm. The test results were calculated against a one-point standard. This biuret colorimetric method was relatively simple, fast, and accurate for the determination of protein in urine and cerebrospinal fluid, with a wide linearity extending from 0.125 g/L up to 6 g/L, had a good correlation with Benzethonium chloride turbidimetry technique, and was a practical routine method. Copyright 2001 Wiley-Liss, Inc.

  8. Application of the angle measure technique as image texture analysis method for the identification of uranium ore concentrate samples: New perspective in nuclear forensics.

    Science.gov (United States)

    Fongaro, Lorenzo; Ho, Doris Mer Lin; Kvaal, Knut; Mayer, Klaus; Rondinella, Vincenzo V

    2016-05-15

    The identification of interdicted nuclear or radioactive materials requires the application of dedicated techniques. In this work, a new approach for characterizing powder of uranium ore concentrates (UOCs) is presented. It is based on image texture analysis and multivariate data modelling. 26 different UOCs samples were evaluated applying the Angle Measure Technique (AMT) algorithm to extract textural features on samples images acquired at 250× and 1000× magnification by Scanning Electron Microscope (SEM). At both magnifications, this method proved effective to classify the different types of UOC powder based on the surface characteristics that depend on particle size, homogeneity, and graininess and are related to the composition and processes used in the production facilities. Using the outcome data from the application of the AMT algorithm, the total explained variance was higher than 90% with Principal Component Analysis (PCA), while partial least square discriminant analysis (PLS-DA) applied only on the 14 black colour UOCs powder samples, allowed their classification only on the basis of their surface texture features (sensitivity>0.6; specificity>0.6). This preliminary study shows that this method was able to distinguish samples with similar composition, but obtained from different facilities. The mean angle spectral data obtained by the image texture analysis using the AMT algorithm can be considered as a specific fingerprint or signature of UOCs and could be used for nuclear forensic investigation. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  9. Simple hollow fiber renewal liquid membrane extraction method for pre-concentration of Cd(II) in environmental samples and detection by Flame Atomic Absorption Spectrometry

    International Nuclear Information System (INIS)

    Carletto, Jeferson Schneider; Luciano, Raquel Medeiros; Bedendo, Gizelle Cristina; Carasek, Eduardo

    2009-01-01

    A hollow fiber renewal liquid membrane (HFRLM) extraction method to determine cadmium (II) in water samples using Flame Atomic Absorption Spectrometry (FAAS) was developed. Ammonium O,O-diethyl dithiophosphate (DDTP) was used to complex cadmium (II) in an acid medium to obtain a neutral hydrophobic complex (ML 2 ). The organic solvent introduced to the sample extracts this complex from the aqueous solution and carries it over the poly(dimethylsiloxane) (PDMS) membrane, that had their walls previously filled with the same organic solvent. The organic solvent is solubilized inside the PDMS membrane, leading to a homogeneous phase. The complex strips the lumen of the membrane where, at higher pH, the complex Cd-DDTP is broken down and cadmium (II) is released into the stripping phase. EDTA was used to complex the cadmium (II), helping to trap the analyte in the stripping phase. A multivariate procedure was used to optimize the studied variables. The optimized variables were: sample (donor phase) pH 3.25, DDTP concentration 0.05% (m/v), stripping (acceptor phase) pH 8.75, EDTA concentration 1.5 x 10 -2 mol L -1 , extraction temperature 40 deg. C, extraction time 40 min, a solvent mixture N-butyl acetate and hexane (60/40%, v/v) with a volume of 100 μL, and addition of ammonium sulfate to saturate the sample. The sample volume used was 20 mL and the stripping volume was 165 μL. The analyte enrichment factor was 120, limit of detection (LOD) 1.3 μg L -1 , relative standard deviation (RSD) 5.5% and the working linear range 2-30 μg L -1 .

  10. Fractional Slot Concentrated Windings: A New Method to Manage the Mutual Inductance between Phases in Three-Phase Electrical Machines and Multi-Star Electrical Machines

    Directory of Open Access Journals (Sweden)

    Olivier Barre

    2015-06-01

    Full Text Available Mutual inductance is a phenomenon caused by the circulation of the magnetic flux in the core of an electrical machine. It is the result of the effect of the current flowing in one phase on the other phases. In conventional three-phase machines, such an effect has no influence on the electrical behaviour of the device. Although these machines are powered by power inverters, no problem should occur. The result is not the same for multi-star machines. If these machines are using a conventional winding structure, namely distributed windings, and are powered by voltage source converters, current ripples appear in the power supply lines. These current ripples are related to magnetic couplings between the stars. Designers should check these current ripples in order to stay within the limits imposed by the specifications. These electric current disturbances also provide torque ripples. With concentrated windings, a new degree of freedom appears; the configuration—number of slots/number of poles—can have a positive impact. The circulation of the magnetic flux is the initial phenomenon that produces the mutual inductance. The main goal of this discussion is to describe a design method that is able to produce not only a machine with low mutual inductance between phases, but also a multi-star machine where the stars and the phases are magnetically decoupled or less coupled. This discussion only takes into account the machines that use permanent magnets mounted on the rotor surface. This article is part of a study aimed at designing a high efficiency generator using fractional-slot concentrated-windings (FSCW.

  11. Identification and Concentration of Some Flavonoid Components in Malaysian Young Ginger (Zingiber officinale Roscoe Varieties by a High Performance Liquid Chromatography Method

    Directory of Open Access Journals (Sweden)

    Asmah Rahmat

    2010-09-01

    Full Text Available Flavonoids make up one of the most pervasive groups of plant phenolics. Due to their importance in plants and human health, it would be useful to have a better understanding of flavonoid concentration and biological activities that could indicate their potentials as therapeutic agents, and also for predicting and controlling the quality of medicinal herbs. Ginger (Zingiber officinale Roscoe is a famous and widely used herb, especially in Asia, that contains several interesting bioactive constituents and possesses health promoting properties. In this study, total flavonoids and some flavonoid components including quercetin, rutin, catechin, epicatechin, kaempferol and naringenin were extracted from the leaves and rhizomes of two varieties of Zingiber officinale (Halia Bentong and Halia Bara at three different growth points (8, 12 and 16 weeks after planting, and analyzed by a high performance liquid chromatography (HPLC method in order to determine the potential of the subterranean part of the young ginger. The results showed that Halia Bara had a higher content of flavonoids in the leaves and rhizomes as compared to Halia Bentong. In both varieties, the concentration of flavonoids in the leaves decreased (Halia Bentong, 42.3%; Halia Bara 36.7%, and in the rhizomes it increased (Halia Bentong 59.6%; Halia Bara 60.1% as the growth period increased. Quercetin was abundant in both varieties. The antioxidant activity determined by the 1,1-diphenyl-2-picryl-hydrazyl (DPPH assay showed high activities (65.7% in the leaves of Halia Bara at 8 weeks after planting. Results suggested a good flavonoid content and antioxidant activity potential in ginger leaves at 8 weeks after planting. The leaves of these ginger varieties could be useful for both food flavourings and in traditional medicine.

  12. Concentrating Radioactivity

    Science.gov (United States)

    Herrmann, Richard A.

    1974-01-01

    By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

  13. Concentration of Hydrogen Peroxide

    Science.gov (United States)

    Parrish, Clyde F. (Inventor)

    2006-01-01

    Methods for concentrating hydrogen peroxide solutions have been described. The methods utilize a polymeric membrane separating a hydrogen peroxide solution from a sweep gas or permeate. The membrane is selective to the permeability of water over the permeability of hydrogen peroxide, thereby facilitating the concentration of the hydrogen peroxide solution through the transport of water through the membrane to the permeate. By utilizing methods in accordance with the invention, hydrogen peroxide solutions of up to 85% by volume or higher may be generated at a point of use without storing substantial quantities of the highly concentrated solutions and without requiring temperatures that would produce explosive mixtures of hydrogen peroxide vapors.

  14. Assessment of Methods for Rapid Intraoperative Concentration and Selection of Marrow-Derived Connective Tissue Progenitors for Bone Regeneration Using the Canine Femoral Multidefect Model

    Science.gov (United States)

    Luangphakdy, Viviane; Boehm, Cynthia; Pan, Hui; Herrick, James; Zaveri, Phil

    2016-01-01

    Treatment of large bone defects remains an unsolved clinical challenge, despite a wide array of existing bone graft materials and strategies. Local deficiency in osteogenic connective tissue progenitors (CTP-Os) due to tissue loss is one of the central biological barriers to bone regeneration. Density separation (DS) and selective retention (SR) represent two promising methods that can be used intraoperatively to rapidly concentrate cells and potentially select CTP-Os. This project was designed to compare DS and SR using the canine femoral multidefect (CFMD) model. Mineralized cancellous allograft (MCA) was used as a standardized scaffold for cell transplantation. Two experiments were performed using a cohort of six animals in each comparison. In Cohort I, unprocessed bone marrow aspirate (BMA) clot was compared to DS processing. MCA combined with raw BMA or DS processed cells produced a robust and advanced stage of bone regeneration throughout the defect in 4 weeks with reconstitution of hematopoietic marrow. However, the retention of DS processed cells and CTP-Os in the MCA matrix was low compared to BMA clot. In Cohort II, MCA with DS-T cells (addition of calcium chloride thrombin to induce clotting and enhance cell and CTP-O retention) was compared to MCA with SR cells. A mean of 276 ± 86 million nucleated cells and 29,030 ± 10,510 CTP-Os were implanted per defect in the DS-T group. A mean of 76 ± 42 million nucleated cells and 30,266 ± 15,850 CTP-Os were implanted in the SR group. Bone formation was robust and not different between treatments. Histologically, both groups demonstrated regeneration of hematopoietic marrow tissue. However, SR sites contained more hematopoietic vascular tissues, less fibrosis, and less residual allograft, particularly in the intramedullary cavity, suggesting a more advanced stage of remodeling (p = 0.04). These data demonstrate excellent overall performance of DS and SR processing methods. Both methods

  15. Application of trajectory clustering and source attribution methods for investigating regional CO2 and CH4 concentrations at Germany's highest mountain site

    Science.gov (United States)

    Giemsa, Esther; Jacobeit, Jucundus; Ries, Ludwig; Frank, Gabriele; Hachinger, Stephan; Meyer-Arnek, Julian

    2017-04-01

    -term) components of the regional CO2 and CH4 concentration time-series are assigned to the back-trajectory clusters. The significant differences in the greenhouse gases' distributions associated with each cluster are confirmed by the non-parametric Kruskal-Wallis test thereby delivering the prerequisites for further investigations, in particular by Potential Source Contribution Functions for the detection of probable locations of within-cluster emission sources. The advantages of this comprehensive approach are site-specificity (by considering trajectories arriving at Schneefernerhaus as well as a site-appropriate filter method) and concentration-specificity (each greenhouse gas has its own source regions) combined with granting the space and time scales related to the synoptic flow patterns in source attribution studies. This research received funding from the Bavarian State Ministry of the Environment and Consumer Protection.

  16. The effect of the method of application and concentration of asahi sl on the response of cucumber plants to chilling stress

    Directory of Open Access Journals (Sweden)

    Edward Borowski

    2012-12-01

    Full Text Available In pot experiments conducted on cucumber cv. Śremski F1, the effect was studied of short-term chilling stress on plants which had grown from seeds germinating in the solution of Asahi SL or treated with this biostimulator during the early growth period. The plants were grown in a phytotron at an air temperature of 27/22°C (day/night, using fluorescent light with FAR flux density of 220 μmol x m-2 x s-1 and with a photoperiod of 16/8. The biostimulator was applied using the following methods: a germination of seeds in 0.01% and 0.05% solution, b watering of plants twice with 0.01% or 0.05% solution, c spraying leaves with 0.3% or 0.5% solution. Plants sprayed with distilled water were the control. After 24 hours from foliar or root application of Asahi SL, one half of the plants from each experimental series was treated for a period of 3 days at a temperature of 12/6°C, with all the other growth conditions unchanged. The obtained results show that short-term chilling stress caused a significant increase in electrolyte leakage, free proline content and in the activity of ascorbate peroxidase in leaves, but a decrease in the content of chlorophyll, its maximum fluorescence (Fm and quantum yield (Fv/Fm, carotenoid content, stomatal conductance, transpiration, photosynthesis, leaf biomass and in the activity of catalase in leaves. Foliar or root application of Asahi SL in the pre-stress period decreased the values of the traits which increased as a result of chilling or increased those which decreased. Higher concentrations of the biostimulator solutions, applied using this method, were more effective. The application of the biostimulator during seed germination did not result in significant changes in the response of plants to chilling stress.

  17. Measuring internal azole and pyrethroid pesticide concentrations in Daphnia magna using QuEChERS and GC-ECD--method development with a focus on matrix effects.

    Science.gov (United States)

    Kretschmann, Andreas; Cedergreen, Nina; Christensen, Jan H

    2016-02-01

    Pyrethroids are highly toxic towards aquatic macroinvertebrates such as Daphnia magna and can be synergized when co-occurring with azole fungicides. A sensitive analytical method for the measurement of azole-pyrethroid mixtures in aquatic macroinvertebrates is not available at present. We developed and validated an extraction, cleanup, and quantification procedure for four pyrethroid insecticides and four azole fungicides at the picograms per milligram wet weight level in D. magna using a QuEChERS approach and GC-ECD analysis. Short- and long-term matrix effects were analyzed by injection of a series of extracts from D. magna, and the best surrogate standards were identified through correlation analysis of analyte responses. The presence of matrix clearly stabilized the analyte responses (≤6% relative standard deviation of peak area compared to up to 22% when injected without matrix). The sensitivity was high with detection limits and limits of quantification between 58-168 and 119-571 pg mg(wet weight)(-1) for the azoles and 5.8-27 and 12-84 pg mg(wet weight)(-1) for the pyrethroids, respectively. Accuracy (% recovery) was between 95 and 111% and the precision (repeatability) below 10% relative standard deviation for all analytes. In the case of prochloraz, α-cypermethrin, and deltamethrin, normalization to surrogate standards led to a clear improvement of accuracy and precision by up to 8 and 4%, respectively. The method was successfully applied to the measurement of internal α-cypermethrin concentrations in D. magna under environmentally relevant exposure conditions (exposure to a pulse in the micrograms per liter range) with and without co-exposure to propiconazole.

  18. Monitoring bacterial contamination in equine platelet concentrates obtained by the tube method in a clean laboratory environment under three different technical conditions.

    Science.gov (United States)

    Alvarez, M E; Giraldo, C E; Carmona, J U

    2010-01-01

    There is a growing interest in the use of autologous platelet concentrates (PCs) as treatment for chronic musculoskeletal diseases in horses. However, there is no information on the risk of bacterial contamination during their preparation. To: 1) assess the risk of bacterial contamination in equine PCs obtained by the tube method under 3 technical conditions: a) in a laminar flow cabinet, in a clean laboratory environment both with (b) and without (c) Bunsen burner; 2) identify the critical points of the process of PCs preparation with risk of bacterial contamination; and 3) identify the potential bacterial contaminants in the process and their antibiotic susceptibility. Bacteriological samples were taken from: the skin (shaved or unshaved) of the venipuncture site in 15 horses, both before and after being disinfected; hands and throat of the operator; caps of the tubes where the blood was processed; environment where the equine blood samples were collected; laboratory environment; laminar flow cabinet; bacteriological stove; and PCs obtained under 3 technical conditions. Bacteria were isolated from nonaseptically prepared equine skin, hands and throat of the operator, and the place where the blood samples were taken. Bacteria were not isolated from tube caps, laboratory environment, laminar flow cabinet or PCs. The isolated bacteria were normal biota from equine skin, human skin and throat, and environmental contaminants. Of the isolated bacteria, 23% were resistant to penicillin, 19% to ampicillin, 2.12% to ceftiofur, 3.2% to sulphamethoxazole/trimethoprim and 1.1% to enrofloxacin. Resistance to amikacin and gentamicin was not seen. Uncontaminated PCs can be obtained by the tube method in a clean laboratory environment without the need for either a laminar flow cabinet or a Bunsen burner. It is mandatory to perform the procedure following strict aseptic technique.

  19. Concentrations of some macro and micro plant nutrient of cultivated soils in Central and Eastern Blacksea Region and their mapping by inverse distance weighted (IDW method

    Directory of Open Access Journals (Sweden)

    Mehmet Arif Özyazıcı

    2015-11-01

    Full Text Available The aim of this study was to determine plant nutrients content and to in terms of soil variables their soil database and generate maps of their distribution on agricultural land in Central and Eastern Black Sea Region using geographical information system (GIS. In this research, total 3400 soil samples (0-20 cm depth were taken at 2.5 x 2.5 km grid points representing agricultural soils. Total nitrogen, extractable calcium, magnesium, sodium, boron, iron, copper, zinc and manganese contents were analysed in collected soil samples. Analysis results of these samples were classified and evaluated for deficiency, sufficiency or excess with respect to plant nutrients. Afterwards, in terms of GIS, a soil database and maps for current status of the study area were created by using inverse distance weighted (IDW interpolation method. According to this research results, it was determined sufficient plant nutrient elements in terms of total nitrogen, extractable iron, copper and manganese in arable soils of Central and Eastern Blacksea Region while, extractable calcium, magnesium, sodium were found good and moderate level in 66.88%, 81.44% and 64.56% of total soil samples, respectively. In addition, insufficient boron and zinc concentration were found in 34.35% and 51.36% of soil samples, respectively.

  20. The Antifungal Inhibitory Concentration Effectiveness Test From Ethanol Seed Arabica Coffee (Coffea arabica) Extract Against The Growth Of Candida albicans Patient Isolate With In Vitro Method

    Science.gov (United States)

    Satria Rakatama, Adam; Pramono, Andri; Yulianti, Retno

    2018-03-01

    Candida albicans are the most frequent cause of Vulvovaginalis Candidiasis infection. Its treatment using antifungal drugs, are oftenly caused side effects. The reduction of C.albicans growth and the reduction of antifungal drugs side effect, were our main purposed. Our study objective is determine the effectiveness of inhibitory power of arabica coffee seed ethanol extract on the growth of C.albicans patient isolates. The type of this research is experimental research. Kirby-bauer method with the Saboraud Dextrose Agar (SDA) media was used in this experiment. Inhibitory zone was observed around the disc, to determine the inhibitory power. The results showed that the inhibitory zone was formed on arabica coffee seed ethanol extract on 10%, 20%, 40%, and 80% concentration. Kruskal-Wallis test results (palbicans patient isolates were smaller compared with C.albicans ATCC 90028 as gold standard. This showed that the virulence of C.albicans from patients isolates were higher. We concluded that arabica coffee seed ethanol extract could inhibiting the growth of C.albicans patient isolates. Optimization of coffee seed ethanol extract to obtain maximum active ingredients still needs to be done. This knowledge is expected to be used for the beginning manufacturer antifungal drug from natural product.

  1. Identification of key factors affecting the water pollutant concentration in the sluice-controlled river reaches of the Shaying River in China via statistical analysis methods.

    Science.gov (United States)

    Dou, Ming; Zhang, Yan; Zuo, Qiting; Mi, Qingbin

    2015-08-01

    The construction of sluices creates a strong disturbance in water environmental factors within a river. The change in water pollutant concentrations of sluice-controlled river reaches (SCRRs) is more complex than that of natural river segments. To determine the key factors affecting water pollutant concentration changes in SCRRs, river reaches near the Huaidian Sluice in the Shaying River of China were selected as a case study, and water quality monitoring experiments based on different regulating modes were implemented in 2009 and 2010. To identify the key factors affecting the change rates for the chemical oxygen demand of permanganate (CODMn) and ammonia nitrogen (NH3-N) concentrations in the SCRRs of the Huaidian Sluice, partial correlation analysis, principal component analysis and principal factor analysis were used. The results indicate four factors, i.e., the inflow quantity from upper reaches, opening size of sluice gates, water pollutant concentration from upper reaches, and turbidity before the sluice, which are the common key factors for the CODMn and NH3-N concentration change rates. Moreover, the dissolved oxygen before a sluice is a key factor for the permanganate concentration from CODMn change rate, and the water depth before a sluice is a key factor for the NH3-N concentration change rate. Multiple linear regressions between the water pollutant concentration change rate and key factors were established via multiple linear regression analyses, and the quantitative relationship between the CODMn and NH3-N concentration change rates and key affecting factors was analyzed. Finally, the mechanism of action for the key factors affecting the water pollutant concentration changes was analyzed. The results reveal that the inflow quantity from upper reaches, opening size of sluice gates, permanganate concentration from CODMn from upper reaches and dissolved oxygen before the sluice have a negative influence and the turbidity before the sluice has a positive

  2. Influence of Zn concentration on the structural and magnetic properties of nanocrystalline Cu1-xZnxFe2O4 mixed ferrites synthesized using novel combustion method

    Science.gov (United States)

    Murugesan, C.; Kambhala, Nagaiah; Angappane, S.; Chandrasekaran, G.

    2017-12-01

    In this work, we report the structural and magnetic properties of nanocrystalline Cu1-xZnxFe2O4 mixed ferrites synthesized using novel combustion method. The prepared samples are spinel structured and the secondary phase α-Fe2O3 is also present in CuFe2O4. The size of the crystallites ranges between 9.6 nm and 31 nm and the lattice constant increases from 8.342 Å to 8.435 Å. The FTIR absorption bands of CuFe2O4 are observed at 571 cm-1 and 409 cm-1 for tetrahedral and octahedral sites, respectively. These bands are shifting to 547 cm-1 and 397 cm-1 for Zn substitution. Raman spectra show the change in local environment of tetrahedral and octahedral interstitial sites with Zn. The FE-SEM images show that the prepared samples are nano sized and the substitution of Zn decreases the agglomeration. The magnetic study reveals that the saturation magnetizations initially increases from 21.45 emu/g (x = 0) to 44.16 emu/g (x = 0.2) and then decreases at 300 K. The superparamagnetic behavior is observed for samples of x ≥ 0.4 concentration. The temperature dependent zero field cooled and field cooled magnetic measurements confirm the superparamagnetic nature and the observed blocking temperature decreases from 120.4 K to 32.3 K. The hysteresis curves measured at 20 K show the coercivity and it varies from 663 Oe to 70 Oe for increasing Zn content.

  3. Increased concentrations of polycyclic aromatic hydrocarbons in Alpine streams during annual snowmelt: investigating effects of sampling method, site characteristics, and meteorology.

    Science.gov (United States)

    Shahpoury, Pourya; Hageman, Kimberly J; Matthaei, Christoph D; Alumbaugh, Robert E; Cook, Michelle E

    2014-10-07

    Silicone passive samplers and macroinvertebrates were used to measure time-integrated concentrations of polycyclic aromatic hydrocarbons (PAHs) in alpine streams during annual snowmelt. The three sampling sites were located near a main highway in Arthur's Pass National Park in the Southern Alps of New Zealand. A similar set of PAH congeners, composed of 2-4 rings, were found in silicone passive samplers and macroinvertebrates. The background PAH concentrations were similar at all sites, implying that proximity to the highway did not affect concentrations. In passive samplers, an increase of PAH concentrations by up to seven times was observed during snowmelt. In macroinvertebrates, the concentration changes were moderate; however, macroinvertebrate sampling did not occur during the main pulse observed in the passive samplers. The extent of vegetation in the catchment appeared to affect the concentration patterns seen at the different stream sites. A strong correlation was found between PAH concentrations in passive samplers and the amount of rainfall in the study area, indicating that the washout of contaminants from snowpack by rainfall was an important process.

  4. Locating Shallow Groundwater Discharge to Streams Near Concentrated Animal Feeding Operations Using Aerial Infrared Thermography: A Novel Potential Pollution Detection Method

    Science.gov (United States)

    Mapes, K. L.; Pricope, N. G.

    2017-12-01

    The Cape Fear River Basin (CFRB) has some of the highest densities of concentrated animal feeding operations (CAFO) in the United States (factoryfarmmap.org) and was recently named one of the country's most endangered rivers (americanrivers.org). There is high potential for CAFO land use to degrade stream water quality by introducing pollutants, primarily nitrates and fecal coliform, into sub-surface and surface waters. The regionally high water table in the Lower CFRB increases the risk of water quality degradation due to increased connectivity of ground- and surface water. The Lower CFRB is periodically subjected to frequent or intense hurricanes, which have been shown to exacerbate water quality issues associated with CAFOs. Additionally, the growing population in this region is placing more pressure on an already taxed water source and will continue to rely on the Cape Fear River for drinking water and wastewater discharge. While there are documented occurrences of groundwater contamination from CAFOs, we still have little understanding on how and where pollution may be entering streams by shallow sub-surface discharge. Shallow groundwater discharge to streams is becoming easier to detect using thermal infrared imaging cameras onboard unmanned aerial systems. The temperature differences between groundwater and stream water are easily distinguished in the resulting images. While this technology cannot directly measure water quality, it can locate areas of shallow groundwater discharge that can later be tested for pollutants using conventional methods. We will utilize a thermal infrared camera onboard a SenseFly eBee Plus to determine the feasibility of using this technology on a larger scale within the Lower CFRB as an inexpensive means of identifying sites of potential pollution input. Aerial surveys will be conducted in two sub-watersheds: one containing swine CAFO and a control that lacks swine CAFO. Information from this study can be integrated into

  5. A dual-channel gas chromatography method for the quantitation of low and high concentrations of NF3 and CF4 to study membrane separation of the two compounds

    OpenAIRE

    Branken, D.J.; Le Roux, J.P.; Krieg, H.M.; Lachmann, G.

    2013-01-01

    A dual-channel gas chromatographic method is described in this paper that can be conveniently used for quantitation of NF3/CF4 mixtures with a thermal conductivity detector (TCD) on one channel for the quantitation of high-concentrations, and a pulsed discharge helium ionization detector (PDHID) on a second channel for the quantitation of low concentrations. It is shown that adequate separation is achieved on both channels with this dual single-column setup in which column switchi...

  6. Effect of breathing fluctuations on cerebral blood flow in demented patients and its correction method using end-tidal CO2 concentration

    International Nuclear Information System (INIS)

    Komatani, Akio; Yamaguchi, Koichi; Kera, Masahiro; Takanashi, Toshiyasu; Shinohara, Masao; Kawakatsu, Shinobu; Yazaki, Mitsuyasu

    1989-01-01

    During mouthpiece respiration of Xe-133 for a measurement of regional cerebral blood flow (rCBF), the breathing pattern of patients fluctuated and it caused a change of end-tidal CO 2 concentration that had an excellent correlation with PaCO 2 in patients without respiratory disease. The end-tidal CO 2 concentration of demented patients varied within lower ranges than senile control group. The range of fluctuation on the end-tidal CO 2 concentration was dependent on the type and the degree of dementia, and it fluctuated most widely at the middle stage of Alzheimer disease. Mean cerebral blood flow increased by 13.9% for each l% increase in end-tidal CO 2 concentration (3.6%/mmHg PaCO 2 ) in the case of demented patients without cerebrovascular disease. To improve the reliability of rCBF in demented patients, especially in Alzheimer disease, the correction of rCBF data for end-tidal CO 2 concentration should be performed. (author)

  7. A global method for handling fluorescence spectra at high concentration derived from the competition between emission and absorption of colloidal CdTe quantum dots.

    Science.gov (United States)

    Noblet, Thomas; Dreesen, Laurent; Hottechamps, Julie; Humbert, Christophe

    2017-10-11

    We investigate the effects of the concentration of CdTe quantum dots (QDs) on their fluorescence in water. The emission spectra, acquired in right angle geometry, exhibit highly variable shapes. The measurements evidence a critical value of the concentration beyond which the intensity and the spectral bandwidth decrease and the fluorescence maximum is redshifted. To account for these observations, we develop a model based on the primary and secondary inner filter effects. The accuracy of the model ensures that the concentration dependent behaviour of QD fluorescence is completely due to inner filter effects. This result is all the more interesting because it precludes the assumption of dynamic quenching. As a matter of fact, the decrease of the emission intensity is not a consequence of collisional quenching but an effect of competition between fluorescence and absorption. We even show that this phenomenon is linked not only to the QD concentration but also to the geometric configuration of the setup. Hence, our analytical model can be easily adapted to every fluorescence spectroscopy configuration to quantitatively predict or correct inner filter effects in the case of QDs or any fluorophore, and thus improve the handling of fluorescence spectroscopy for highly concentrated solutions.

  8. Monitoring and assessment of heavy metal/metalloid concentration by inductively coupled plasma mass spectroscopy (ICP-MS) method in Gonyeli Lake, Cyprus.

    Science.gov (United States)

    Alkas, Fehmi Burak; Shaban, Jehad Abdullah; Sukuroglu, Ayca Aktas; Kurt, Mehmet Ali; Battal, Dilek; Saygi, Sahan

    2017-09-22

    The presence of heavy metals/metalloids in the ecosystem has been an increasing ecological and global public health concern due to their potential to cause adverse health effects. For this reason, the accumulation of some heavy metals such as Cr, Mn, Ni, Cu, As, Cd, Pb was assessed by way of ICP-MS in water, sediment and fish (Cyprinus carpio) sampled from Gonyeli Lake, North Cyprus. The results showed that these metals/metalloids are found widespread throughout the study area. In water, most concentrated element was manganese with 92.1 ppb and least concentrated was lead with 0.914 ppb. In sediment, copper had the highest concentration with 613 ppm, and cadmium the lowest with 1.57 ppm. In fish tissues (muscle and gills), the most concentrated element was manganese with 12.5 ppm and the least concentrated cadmium with 0.017 ppm. These results indicate that future remediation efforts are indispensable for the rehabilitation of the lake.

  9. Comparison of two methods using plasma triglyceride concentration as a surrogate estimate of insulin action in nondiabetic subjects: triglycerides × glucose versus triglyceride/high-density lipoprotein cholesterol.

    Science.gov (United States)

    Abbasi, Fahim; Reaven, Gerald M

    2011-12-01

    The objective was to compare relationships between insulin-mediated glucose uptake and surrogate estimates of insulin action, particularly those using fasting triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) concentrations. Insulin-mediated glucose uptake was quantified by determining the steady-state plasma glucose (SSPG) concentration during the insulin suppression test in 455 nondiabetic subjects. Fasting TG, HDL-C, glucose, and insulin concentrations were measured; and calculations were made of the following: (1) plasma concentration ratio of TG/HDL-C, (2) TG × fasting glucose (TyG index), (3) homeostasis model assessment of insulin resistance, and (4) insulin area under the curve (insulin-AUC) during a glucose tolerance test. Insulin-AUC correlated most closely with SSPG (r ∼ 0.75, P < .001), with lesser but comparable correlations between SSPG and TG/HDL-C ratio, TyG index, homeostasis model assessment of insulin resistance, and fasting TG and insulin (r ∼ 0.60, P < .001). Calculations of TG/HDL-C ratio and TyG index correlated with SSPG concentration to a similar degree, and the relationships were comparable to estimates using fasting insulin. The strongest relationship was between SSPG and insulin-AUC. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Method of estimating maximum VOC concentration in void volume of vented waste drums using limited sampling data: Application in transuranic waste drums

    International Nuclear Information System (INIS)

    Liekhus, K.J.; Connolly, M.J.

    1995-01-01

    A test program has been conducted at the Idaho National Engineering Laboratory to demonstrate that the concentration of volatile organic compounds (VOCs) within the innermost layer of confinement in a vented waste drum can be estimated using a model incorporating diffusion and permeation transport principles as well as limited waste drum sampling data. The model consists of a series of material balance equations describing steady-state VOC transport from each distinct void volume in the drum. The primary model input is the measured drum headspace VOC concentration. Model parameters are determined or estimated based on available process knowledge. The model effectiveness in estimating VOC concentration in the headspace of the innermost layer of confinement was examined for vented waste drums containing different waste types and configurations. This paper summarizes the experimental measurements and model predictions in vented transuranic waste drums containing solidified sludges and solid waste

  11. Conical electromagnetic radiation flux concentrator

    Science.gov (United States)

    Miller, E. R.

    1972-01-01

    Concentrator provides method of concentrating a beam of electromagnetic radiation into a smaller beam, presenting a higher flux density. Smaller beam may be made larger by sending radiation through the device in the reverse direction.

  12. Method

    Directory of Open Access Journals (Sweden)

    Ling Fiona W.M.

    2017-01-01

    Full Text Available Rapid prototyping of microchannel gain lots of attention from researchers along with the rapid development of microfluidic technology. The conventional methods carried few disadvantages such as high cost, time consuming, required high operating pressure and temperature and involve expertise in operating the equipment. In this work, new method adapting xurography method is introduced to replace the conventional method of fabrication of microchannels. The novelty in this study is replacing the adhesion film with clear plastic film which was used to cut the design of the microchannel as the material is more suitable for fabricating more complex microchannel design. The microchannel was then mold using polymethyldisiloxane (PDMS and bonded with a clean glass to produce a close microchannel. The microchannel produced had a clean edge indicating good master mold was produced using the cutting plotter and the bonding between the PDMS and glass was good where no leakage was observed. The materials used in this method is cheap and the total time consumed is less than 5 hours where this method is suitable for rapid prototyping of microchannel.

  13. Optimization Concentration of Sulfuric Acid on the Reduction U(VI) UsingJones Reductor to U(IV) with UV-VIS Spectrophotometry Method

    International Nuclear Information System (INIS)

    Simbolon, Sahat

    2000-01-01

    Reduction of U(VI) solution in sulfuric acid media with reductor Jones invarying concentration of sulfuric acid from 0.05 M - 1.5 M had been done.Compound of U 3 O 8 was used as a standard, it was dissolved in varying ofsulfuric acid from 0.05 M to 1.5 M, the amount of U(IV) was determined bytitration with KMnO 4 solution. The amount of U(VI) in solution was based onthe concentration U(IV) and the U 3 O 8 formula. Each concentration ofsulfuric acid 0.05 M to 1.5 M were used to dissolve U 3 O 8 and it was used tocalibrate the amount of U(IV) in solution after reduction with Jonesreductor. Analysis varian was used to determine the difference the absorbanceof uranyl sulfate. It was found that optimum concentration of sulfuric acidmedia for reduction U(VI) solution to U(IV) was 0.5 M. (author)

  14. Comparison of sensitivity and specificity of 4 methods for detection of Giardia duodenalis in feces: immunofluorescence and PCR are superior to microscopy of concentrated iodine-stained samples.

    Science.gov (United States)

    Gotfred-Rasmussen, Helle; Lund, Marianne; Enemark, Heidi L; Erlandsen, Mogens; Petersen, Eskild

    2016-03-01

    For decades, microscopy of feces after formol-ethylacetate (FEA) concentration and iodine staining has been the routine test for intestinal protozoa. Lately, polymerase chain reaction or fluorescence-labeled parasite-specific antibodies have been introduced, but their place in everyday routine diagnostics has not yet been established. We compared FEA and salt-sugar flotation (SSF) concentration followed by microscopy of iodine-stained concentrate and immunofluorescence assay (IFA) and real-time polymerase chain reaction (qPCR) for detection of Giardia duodenalis in human feces. The median number of Giardia cysts found by FEA in 19 Giardia-positive samples was 50 cysts per gram (CPG), by SSF 350 CPG, by IFA 76,700 CPG, and by qPCR 316,000 CPG. We next tested 455 consecutive samples for presence of Giardia cysts. Using IFA as reference, qPCR had a sensitivity of 91%, specificity of 95.1%, a false-positive rate of 50%, a false-negative rate of 0.48%, a positive predictive value of 50%, and a negative predictive value of 99.5%. In conclusion, qPCR and IFA were significantly more sensitive than microscopy of iodine-stained concentrates using either FEA or SSF. We suggest, when using qPCR, that positive samples are verified by IFA to prevent false-positive results. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  15. Method to determine the activity concentration and total activity of radioactive waste; Metodo para determinar la concentracion de actividad y actividad total de desechos radiactivos

    Energy Technology Data Exchange (ETDEWEB)

    Angeles C, A

    2001-02-15

    A characteristic system of radioactive waste is described to determine the concentration of radionuclides activity and the total activity of bundles of radioactive waste. The system this integrated by three subsystems: - Elevator of drums. - Electromechanics. - Gamma spectroscopy. In the system it is analyzed waste of issuing gamma specifically, and this designed for materials of relative low density and it analyzes materials of cylindrical recipients.

  16. Concentrating photovoltaic solar panel

    Science.gov (United States)

    Cashion, Steven A; Bowser, Michael R; Farrelly, Mark B; Hines, Braden E; Holmes, Howard C; Johnson, Jr., Richard