In-core LOCA-s: analytical solution for the delayed mixing model for moderator poison concentration

International Nuclear Information System (INIS)

Firla, A.P.

1995-01-01

Solutions to dynamic moderator poison concentration model with delayed mixing under single pressure tube / calandria tube rupture scenario are discussed. Such a model is described by a delay differential equation, and for such equations the standard ways of solution are not directly applicable. In the paper an exact, direct time-domain analytical solution to the delayed mixing model is presented and discussed. The obtained solution has a 'marching' form and is easy to calculate numerically. Results of the numerical calculations based on the analytical solution indicate that for the expected range of mixing times the existing uniform mixing model is a good representation of the moderator poison mixing process for single PT/CT breaks. However, for postulated multi-pipe breaks ( which is very unlikely to occur ) the uniform mixing model is not adequate any more; at the same time an 'approximate' solution based on Laplace transform significantly overpredicts the rate of poison concentration decrease, resulting in excessive increase in the moderator dilution factor. In this situation the true, analytical solution must be used. The analytical solution presented in the paper may also serve as a bench-mark test for the accuracy of the existing poison mixing models. Moreover, because of the existing oscillatory tendency of the solution, special care must be taken in using delay differential models in other applications. (author). 3 refs., 3 tabs., 8 figs

Results Of Analytical Sample Crosschecks For Next Generation Solvent Extraction Samples Isopar L Concentration And pH

International Nuclear Information System (INIS)

Peters, T.; Fink, S.

2011-01-01

As part of the implementation process for the Next Generation Cesium Extraction Solvent (NGCS), SRNL and F/H Lab performed a series of analytical cross-checks to ensure that the components in the NGCS solvent system do not constitute an undue analytical challenge. For measurement of entrained Isopar(reg s ign) L in aqueous solutions, both labs performed similarly with results more reliable at higher concentrations (near 50 mg/L). Low bias occurred in both labs, as seen previously for comparable blind studies for the baseline solvent system. SRNL recommends consideration to use of Teflon(trademark) caps on all sample containers used for this purpose. For pH measurements, the labs showed reasonable agreement but considerable positive bias for dilute boric acid solutions. SRNL recommends consideration of using an alternate analytical method for qualification of boric acid concentrations.

Extraction of fullerenes from environmental matrices as affected by solvent characteristics and analyte concentration.

Science.gov (United States)

Place, Benjamin J; Kleber, Markus; Field, Jennifer A

2013-03-01

Fullerenes possess unique chemical properties that make the isolation of these compounds from heterogeneous environmental matrices difficult. For example, previous reports indicate that toluene-based extraction techniques vary in their ability to extract C60, especially from highly carbonaceous solid matrices. Here, we examined the effects of (i) solvent type (toluene alone versus an 80:20 v/v mixture of toluene and 1-methylnaphthalene) and (ii) analyte concentration on the extraction efficiency of an isotopically labeled surrogate compound, (13)C60. The toluene/1-methylnaphthalene mixture increased fullerene extraction efficiency from carbon lampblack by a factor of five, but was not significantly different from 100% toluene when applied to wood stove soot or montmorillonite. Recovery of the (13)C60 surrogate declined with decreasing analyte concentration. The usefulness of isotopically labeled surrogate is demonstrated and the study provides a quantitative assessment regarding the dependence of fullerene extraction efficiencies on the geochemical characteristics of solid matrices. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gender-partitioned patient medians of serum albumin requested by general practitioners for the assessment of analytical stability

DEFF Research Database (Denmark)

Hansen, Steen Ingemann; Petersen, Per Hyltoft; Lund, Flemming

2017-01-01

BACKGROUND: Recently, the use of separate gender-partitioned patient medians of serum sodium has revealed potential for monitoring analytical stability within the optimum analytical performance specifications for laboratory medicine. The serum albumin concentration depends on whether a patient...... patients were closely related despite considerable variation due to the current analytical variation. This relationship was confirmed by the calculated half-range for the monthly ratio between the genders of 0.44%, which surpasses the optimum analytical performance specification for bias of serum albumin...... (0.72%). The weekly ratio had a half-range of 1.83%, which surpasses the minimum analytical performance specifications of 2.15%. CONCLUSIONS: Monthly gender-partitioned patient medians of serum albumin are useful for monitoring of long-term analytical stability, where the gender medians are two...

Analytical Study of High Concentration PCB Paint at the Heavy Water Components Test Reactor

International Nuclear Information System (INIS)

Lowry, N.J.

1998-01-01

This report provides results of an analytical study of high concentration PCB paint in a shutdown nuclear test reactor located at the US Department of Energy's Savannah River Site (SRS). The study was designed to obtain data relevant for an evaluation of potential hazards associated with the use of and exposure to such paints

Analytical Study of High Concentration PCB Paint at the Heavy Water Components Test Reactor

Energy Technology Data Exchange (ETDEWEB)

Lowry, N.J.

1998-10-21

This report provides results of an analytical study of high concentration PCB paint in a shutdown nuclear test reactor located at the US Department of Energy's Savannah River Site (SRS). The study was designed to obtain data relevant for an evaluation of potential hazards associated with the use of and exposure to such paints.

Analytical sensitivity of rapid isotopic analysis of water by refractometry for monitoring D2O concentration in nuclear reactor

International Nuclear Information System (INIS)

Dhole, K.; Tripathy, M.K.; Ghadigaonkar, R.D.; Datta, A.; Bose, H.; Roy, M.

2011-01-01

The feasibility of refractometry for rapid measurement of D 2 O (heavy water) concentration has been studied. Refractometry has been utilised to be an excellent analytical technique to quickly and non-invasively determine D 2 O concentration in water samples without using any chemical reagents. The measurement of refractive index property of water samples with use of temperature control has been utilized for the purpose of their quantitative analysis. The calibration performance provided a reasonable analytical sensitivity of this technique in the 1-100% D 2 O range. (author)

Can neutral analytes be concentrated by transient isotachophoresis in micellar electrokinetic chromatography and how much?

Science.gov (United States)

Matczuk, Magdalena; Foteeva, Lidia S; Jarosz, Maciej; Galanski, Markus; Keppler, Bernhard K; Hirokawa, Takeshi; Timerbaev, Andrei R

2014-06-06

Transient isotachophoresis (tITP) is a versatile sample preconcentration technique that uses ITP to focus electrically charged analytes at the initial stage of CE analysis. However, according to the ruling principle of tITP, uncharged analytes are beyond its capacity while being separated and detected by micellar electrokinetic chromatography (MEKC). On the other hand, when these are charged micelles that undergo the tITP focusing, one can anticipate the concentration effect, resulting from the formation of transient micellar stack at moving sample/background electrolyte (BGE) boundary, which increasingly accumulates the analytes. This work expands the enrichment potential of tITP for MEKC by demonstrating the quantitative analysis of uncharged metal-based drugs from highly saline samples and introducing to the BGE solution anionic surfactants and buffer (terminating) co-ions of different mobility and concentration to optimize performance. Metallodrugs of assorted lipophilicity were chosen so as to explore whether their varying affinity toward micelles plays the role. In addition to altering the sample and BGE composition, optimization of the detection capability was achieved due to fine-tuning operational variables such as sample volume, separation voltage and pressure, etc. The results of optimization trials shed light on the mechanism of micellar tITP and render effective determination of selected drugs in human urine, with practical limits of detection using conventional UV detector. Copyright © 2014 Elsevier B.V. All rights reserved.

Analytical solution for a strained reinforcement layer bonded to lip-shaped crack under remote mode Ⅲ uniform load and concentrated load

Institute of Scientific and Technical Information of China (English)

You-wen LIU; Chao XIE; Chun-zhi JIANG; Qi-hong FANG

2010-01-01

In this paper,the analytical solution of stress field for a strained reinforcement layer bonded to a lip-shaped crack under a remote mode Ⅲ uniform load and a concentrated load is obtained explicitly in the series form by using the technical of conformal mapping and the method of analytic continuation.The effects of material combinations,bond of interface and geometric configurations on interfacial stresses generated by eigenstrain,remote load and concentrated load are studied.The results show that the stress concentration and interfacial stresses can be reduced by rational material combinations and geometric configurations designs for different load forms.

Effect of prenatal exposure to different salt concentration on the third month's weight and blood pressure in wistar rat

International Nuclear Information System (INIS)

Fereidoun, H.

2009-01-01

In utero alterations in fluid and electrolyte endocrine systems may result in permanent effects on offspring. A low sodium intake during prenatal life jeopardizes growth in young rats, prenatal high-salt diet in Sprague-Dawley rats caused an increase in MAP at postnatal day 30. The objective of this study was to determine the effect of prenatal exposure to different salt concentrations on the third month's weight and blood pressure in Wistar rat. This study was performed at the Department of Physiology, Isfahan University of Medical Science, Isfahan, Iran, over a period from 1998 to 2003. Six groups of rat, 1 male and 5 female in each group were exposed to 0.5, 1, 1.4, 1.6, 1.8 and 2 percent of salt concentrations during pre-pregnancy, pregnancy and lactation period, another test group consumed distilled water and control group used Isfahan tap water, other living conditions for all groups were similar. Exposure to different salt concentrations on the third month's weight and blood pressure was evaluated. Prenatal exposure to 0.5 and 1% salt concentrations gives birth to more alive and healthy infants, and third month's weight increased significantly, but blood pressure was not influenced significantly. Salt concentrations higher than 1% increased the maternal and infant mortality rate and blood pressure significantly, but some concentrations decreased third month's weight significantly. Level of dietary salt during intrauterine development can influence on the number of alive and healthy infants, birth weight, third month' weight and blood pressure significantly. There is no need to introduce a salt restricted diet in prenatal care, a balanced diet in sodium during pregnancy is recommended, high salt diet creates harmful effect. (author)

Satellite-derived ice data sets no. 2: Arctic monthly average microwave brightness temperatures and sea ice concentrations, 1973-1976

Science.gov (United States)

Parkinson, C. L.; Comiso, J. C.; Zwally, H. J.

1987-01-01

A summary data set for four years (mid 70's) of Arctic sea ice conditions is available on magnetic tape. The data include monthly and yearly averaged Nimbus 5 electrically scanning microwave radiometer (ESMR) brightness temperatures, an ice concentration parameter derived from the brightness temperatures, monthly climatological surface air temperatures, and monthly climatological sea level pressures. All data matrices are applied to 293 by 293 grids that cover a polar stereographic map enclosing the 50 deg N latitude circle. The grid size varies from about 32 X 32 km at the poles to about 28 X 28 km at 50 deg N. The ice concentration parameter is calculated assuming that the field of view contains only open water and first-year ice with an ice emissivity of 0.92. To account for the presence of multiyear ice, a nomogram is provided relating the ice concentration parameter, the total ice concentration, and the fraction of the ice cover which is multiyear ice.

Higher Leptin but Not Human Milk Macronutrient Concentration Distinguishes Normal-Weight from Obese Mothers at 1-Month Postpartum.

Science.gov (United States)

De Luca, Arnaud; Frasquet-Darrieux, Marine; Gaud, Marie-Agnès; Christin, Patricia; Boquien, Clair-Yves; Millet, Christine; Herviou, Manon; Darmaun, Dominique; Robins, Richard J; Ingrand, Pierre; Hankard, Régis

2016-01-01

Exclusively breastfed infants born to obese mothers have previously been shown to gain less weight by 1-month postpartum than infants of normal-weight mothers. Our hypothesis is that human milk composition and volume may differ between obese and normal-weight mothers. To compare human milk leptin, macronutrient concentration, and volume in obese and normal-weight mothers. Mother and infant characteristics were studied as secondary aims. This cross-sectional observational study compared 50 obese mothers matched for age, parity, ethnic origin, and educational level with 50 normal-weight mothers. Leptin, macronutrient human milk concentration, and milk volume were determined at 1 month in exclusively breastfed infants. Mother characteristics and infant growth were recorded. Human milk leptin concentration was higher in obese mothers than normal-weight mothers (4.8±2.7 vs. 2.5±1.5 ng.mL-1, pobese and normal-weight mothers in protein, lipid, carbohydrate content, and volume, nor in infant weight gain. Leptin concentration was higher in the milk of obese mothers than that of normal-weight mothers, but macronutrient concentration was not. It remains to be established whether the higher leptin content impacts on infant growth beyond the 1-month of the study period.

Post-analytical stability of 23 common chemistry and immunochemistry analytes in incurred samples

DEFF Research Database (Denmark)

Nielsen, Betina Klint; Frederiksen, Tina; Friis-Hansen, Lennart

2017-01-01

BACKGROUND: Storage of blood samples after centrifugation, decapping and initial sampling allows ordering of additional blood tests. The pre-analytic stability of biochemistry and immunochemistry analytes has been studied in detail, but little is known about the post-analytical stability...... in incurred samples. METHODS: We examined the stability of 23 routine analytes on the Dimension Vista® (Siemens Healthineers, Denmark): 42-60 routine samples in lithium-heparin gel tubes (Vacutainer, BD, USA) were centrifuged at 3000×g for 10min. Immediately after centrifugation, initial concentration...... of analytes were measured in duplicate (t=0). The tubes were stored decapped at room temperature and re-analyzed after 2, 4, 6, 8 and 10h in singletons. The concentration from reanalysis were normalized to initial concentration (t=0). Internal acceptance criteria for bias and total error were used...

Analytical Expressions Pertaining to the Concentration of Substrates and Product in Phenol-Polyphenol Oxidase System Immobilized in Laponite Hydrogels: A Reciprocal Competitive Inhibition Process

Directory of Open Access Journals (Sweden)

K. Indira

2012-01-01

Full Text Available Theoretical analysis corresponding to the diffusion and kinetics of substrate and product in an amperometric biosensor is developed and reported in this paper. The nonlinear coupled system of diffusion equations was analytically solved by Homotopy perturbation method. Herein, we report the approximate analytical expressions pertaining to substrate concentration, product concentration, and current response for all possible values of diffusion and kinetic parameters. The numerical solution of this problem is also reported using Scilab/Matlab program. Also, we found excellent agreement between the analytical results and numerical results upon comparison.

Risk-informed Analytical Approaches to Concentration Averaging for the Purpose of Waste Classification

International Nuclear Information System (INIS)

Esh, D.W.; Pinkston, K.E.; Barr, C.S.; Bradford, A.H.; Ridge, A.Ch.

2009-01-01

Nuclear Regulatory Commission (NRC) staff has developed a concentration averaging approach and guidance for the review of Department of Energy (DOE) non-HLW determinations. Although the approach was focused on this specific application, concentration averaging is generally applicable to waste classification and thus has implications for waste management decisions as discussed in more detail in this paper. In the United States, radioactive waste has historically been classified into various categories for the purpose of ensuring that the disposal system selected is commensurate with the hazard of the waste such that public health and safety will be protected. However, the risk from the near-surface disposal of radioactive waste is not solely a function of waste concentration but is also a function of the volume (quantity) of waste and its accessibility. A risk-informed approach to waste classification for near-surface disposal of low-level waste would consider the specific characteristics of the waste, the quantity of material, and the disposal system features that limit accessibility to the waste. NRC staff has developed example analytical approaches to estimate waste concentration, and therefore waste classification, for waste disposed in facilities or with configurations that were not anticipated when the regulation for the disposal of commercial low-level waste (i.e. 10 CFR Part 61) was developed. (authors)

Analytical solutions to compartmental indoor air quality models with application to environmental tobacco smoke concentrations measured in a house.

Science.gov (United States)

Ott, Wayne R; Klepeis, Neil E; Switzer, Paul

2003-08-01

This paper derives the analytical solutions to multi-compartment indoor air quality models for predicting indoor air pollutant concentrations in the home and evaluates the solutions using experimental measurements in the rooms of a single-story residence. The model uses Laplace transform methods to solve the mass balance equations for two interconnected compartments, obtaining analytical solutions that can be applied without a computer. Environmental tobacco smoke (ETS) sources such as the cigarette typically emit pollutants for relatively short times (7-11 min) and are represented mathematically by a "rectangular" source emission time function, or approximated by a short-duration source called an "impulse" time function. Other time-varying indoor sources also can be represented by Laplace transforms. The two-compartment model is more complicated than the single-compartment model and has more parameters, including the cigarette or combustion source emission rate as a function of time, room volumes, compartmental air change rates, and interzonal air flow factors expressed as dimensionless ratios. This paper provides analytical solutions for the impulse, step (Heaviside), and rectangular source emission time functions. It evaluates the indoor model in an unoccupied two-bedroom home using cigars and cigarettes as sources with continuous measurements of carbon monoxide (CO), respirable suspended particles (RSP), and particulate polycyclic aromatic hydrocarbons (PPAH). Fine particle mass concentrations (RSP or PM3.5) are measured using real-time monitors. In our experiments, simultaneous measurements of concentrations at three heights in a bedroom confirm an important assumption of the model-spatial uniformity of mixing. The parameter values of the two-compartment model were obtained using a "grid search" optimization method, and the predicted solutions agreed well with the measured concentration time series in the rooms of the home. The door and window positions in

Analytics: What We're Hearing

Science.gov (United States)

Oblinger, Diana

2012-01-01

Over the last few months, EDUCAUSE has been focusing on analytics. As people hear from experts, meet with association members, and watch the marketplace evolve, a number of common themes are emerging. Conversations have shifted from "What is analytics?" to "How do we get started, and how do we use analytics well?" What people are hearing from…

Comparison of the acetyl bromide spectrophotometric method with other analytical lignin methods for determining lignin concentration in forage samples.

Science.gov (United States)

Fukushima, Romualdo S; Hatfield, Ronald D

2004-06-16

Present analytical methods to quantify lignin in herbaceous plants are not totally satisfactory. A spectrophotometric method, acetyl bromide soluble lignin (ABSL), has been employed to determine lignin concentration in a range of plant materials. In this work, lignin extracted with acidic dioxane was used to develop standard curves and to calculate the derived linear regression equation (slope equals absorptivity value or extinction coefficient) for determining the lignin concentration of respective cell wall samples. This procedure yielded lignin values that were different from those obtained with Klason lignin, acid detergent acid insoluble lignin, or permanganate lignin procedures. Correlations with in vitro dry matter or cell wall digestibility of samples were highest with data from the spectrophotometric technique. The ABSL method employing as standard lignin extracted with acidic dioxane has the potential to be employed as an analytical method to determine lignin concentration in a range of forage materials. It may be useful in developing a quick and easy method to predict in vitro digestibility on the basis of the total lignin content of a sample.

Gender-partitioned patient medians of serum albumin requested by general practitioners for the assessment of analytical stability.

Science.gov (United States)

Hansen, Steen Ingemann; Petersen, Per Hyltoft; Lund, Flemming; Fraser, Callum G; Sölétormos, György

2018-04-25

Recently, the use of separate gender-partitioned patient medians of serum sodium has revealed potential for monitoring analytical stability within the optimum analytical performance specifications for laboratory medicine. The serum albumin concentration depends on whether a patient is sitting or recumbent during phlebotomy. We therefore investigated only examinations requested by general practitioners (GPs) to provide data from sitting patients. Weekly and monthly patient medians of serum albumin requested by GP for both male and female patients were calculated from the raw data obtained from three analysers in the hospital laboratory on examination of samples from those >18 years. The half-range of medians were applied as an estimate of the maximum bias. Further, the ratios between the two medians were calculated (females/males). The medians for male and female patients were closely related despite considerable variation due to the current analytical variation. This relationship was confirmed by the calculated half-range for the monthly ratio between the genders of 0.44%, which surpasses the optimum analytical performance specification for bias of serum albumin (0.72%). The weekly ratio had a half-range of 1.83%, which surpasses the minimum analytical performance specifications of 2.15%. Monthly gender-partitioned patient medians of serum albumin are useful for monitoring of long-term analytical stability, where the gender medians are two independent estimates of changes in (delta) bias: only results requested by GP are of value in this application to ensure that all patients are sitting during phlebotomy.

Analytical and experimental study of two concentric cylinders coupled by a fluid gap

International Nuclear Information System (INIS)

Mulcahy, T.M.; Turula, P.; Chung, H.; Jendrzejczyk, J.A.

1975-04-01

A breeder reactor vessel is a substantial steel cylinder which is partially protected from the nuclear reaction temperature by a relatively thin concentric shell separated from the vessel by a narrow fluid-filled gap. An experimental and analytical study of the vibration of a model of such a shell used in the Fast Test Reactor is described. The analytical work consists first using a free vibration solution of the shell in vacuum as a basis for extrapolating vibration behavior for the same shell with a fluid gap. Then a direct finite element solution is found for the actual problem--the shell and the fluid coupling it to the rigid outer container. All the finite element computations were carried out using the NASTRAN program. The experimental setup consisted of a steel sheet rolled and welded into a cylinder, free at the top edge and at the bottom soldered to a disc which in turn was bolted to a heavy base plate. The fluid gap was provided by using a thick concrete shell as the outer cylinder. A series of these cylinders was used to provide several sizes of annular gap. The case of the steel shell alone, without fluid, was also considered. The steel cylinder was vibrated by an electromagnetic exciter using both harmonic loading and random loading functions. In general, correspondence of experimental and analytical results is within acceptable limits; however, several vibration modes corresponding to solutions with low circumferential wave numbers were not detected experimentally. Response analysis performed to compare the response amplitude at various modes indicates that the intensity at the modes in question is very low. (U.S.)

Analytic validation and comparison of three commercial immunoassays for measurement of plasma atrial/A-type natriuretic peptide concentration in horses

DEFF Research Database (Denmark)

Trachsel, D S; Schwarzwald, C C; Grenacher, B

2014-01-01

Measurement of atrial/A-type natriuretic peptide (ANP) concentrations may be of use for assessment of cardiac disease, and reliable data on the analytic performance of available assays are needed. To assess the suitability for clinical use of commercially available ANP assays, intra-assay and inter......-Altman analyses. For all assays, precision was moderate but acceptable and dilution parallelism was good. All assays showed analytic performance similar to other immunoassays used in veterinary medicine. However, the results from the three assays were poorly comparable. Our study highlights the need...

[Influence of the amount of concentrate feeding on concentrate intake and development of body weight and growth parameters of suckling foals from birth until the 6th month of life].

Science.gov (United States)

Mack, J K; Remler, H P; Senckenberg, E; Kienzle, E

2012-01-01

The objective of this study was to investigate the effects of a different energy supply on the development of Warmblood foals with a focus on examining the recommended allowances of the German Society for Nutrition Physiology. Two groups of foals received different amounts of concentrates from the 1st until the 6th month of life. With regards to the total energy content, the rations were composed to either comply with the recommendations (6) (group "Norm", n=15) or to exceed those by approximately 20% (group "Zulage", n=16). The supply with concentrates of the group "Norm" aimed for a total energy intake of 73 MJ DE/animal/day, the intake of the group "Zulage" of 87 MJ DE/animal/day. Both groups were provided with the same amount of foal starter feed, but different amounts of oats. Both groups were supplied with 1.0, 1.2, 2.0, 2.0 and 2.35 kg foal starter feed per animal and day from the 2nd until the 6th month of life. Additionally, 0.6, 0.7, 0.5, 0.8 and 0.45 kg oats per animal and day (group "Norm") and 1.8, 2.0, 1.75, 2.0 and 1.75 kg (group "Zulage") were offered during months 2 to 6. The animals were fed twice daily. The roughage consisted of a late first cut of haylage. The animals were out to pasture for several hours/day. Individual concentrate intake, body mass and body condition score (BCS) as well as several other growth parameters were recorded. The total amount of haylage consumed by all animals was documented. The daily average intake of concentrates lay between 0.4 ("Norm") and 0.5 kg ("Zulage") in the 2nd month and between 2.8 ("Norm") and 3.7 kg ("Zulage") in the 6th month. The groups did not differ in any recorded parameter. The amount of concentrates offered was entirely eaten for the first time at an age of approximately 180 days. The results suggest that the energy requirements of foals are approximately 10-20% lower than the recommendations.

assessment of concentration of air pollutants using analytical and numerical solution of the atmospheric diffusion equation

International Nuclear Information System (INIS)

Esmail, S.F.H.

2011-01-01

The mathematical formulation of numerous physical problems a results in differential equations actually partial or ordinary differential equations.In our study we are interested in solutions of partial differential equations.The aim of this work is to calculate the concentrations of the pollution, by solving the atmospheric diffusion equation(ADE) using different mathematical methods of solution. It is difficult to solve the general form of ADE analytically, so we use some assumptions to get its solution.The solutions of it depend on the eddy diffusivity profiles(k) and the wind speed u. We use some physical assumptions to simplify its formula and solve it. In the present work, we solve the ADE analytically in three dimensions using Green's function method, Laplace transform method, normal mode method and these separation of variables method. Also, we use ADM as a numerical method. Finally, comparisons are made with the results predicted by the previous methods and the observed data.

Analysis of dissolved organic carbon concentration and 13C isotopic signature by TOC-IRMS - assessment of analytical performance

Science.gov (United States)

Kirkels, Frédérique; Cerli, Chiara; Federherr, Eugen; Kalbitz, Karsten

2013-04-01

Stable carbon isotopes provide a powerful tool to assess carbon pools and their dynamics. Dissolved organic carbon (DOC) has been recognized to play an important role in ecosystem functioning and carbon cycling and has therefore gained increased research interest. However, direct measurement of 13C isotopic signature of carbon in the dissolved phase is technically challenging particularly using high temperature combustion. Until recently, mainly custom-made systems existed which were modified for coupling of TOC instruments with IRMS for simultaneous assessment of C content and isotopic signature. The variety of coupled systems showed differences in their analytical performances. For analysis of DOC high temperature combustion is recognized as best performing method, owing to its high efficiency of conversion to CO2 also for highly refractory components (e.g. humic, fulvic acids) present in DOC and soil extracts. Therefore, we tested high temperature combustion TOC coupled to IRMS (developed by Elementar Group) for bulk measurements of DOC concentration and 13C signature. The instruments are coupled via an Interface to exchange the carrier gas from O2 to He and to concentrate the derived CO2 for the isotope measurement. Analytical performance of the system was assessed for a variety of organic compounds characterized by different stability and complexity, including humic acid and DOM. We tested injection volumes between 0.2-3 ml, thereby enabling measurement of broad concentration ranges. With an injection volume of 0.5 ml (n=3, preceded by 1 discarded injection), DOC and 13C signatures for concentrations between 5-150 mg C/L were analyzed with high precision (standard deviation (SD) predominantly TOC-IRMS in comparison with other systems capable of determining C concentration and isotopic signatures. We recognize the advantages of this system providing: - High sample throughput, short measurement time (15 minutes), flexible sample volume - Easy maintenance

Analytical evaluation of BEA zeolite for the pre-concentration of polycyclic aromatic hydrocarbons and their subsequent chromatographic analysis in water samples.

Science.gov (United States)

Wilson, Walter B; Costa, Andréia A; Wang, Huiyong; Dias, José A; Dias, Sílvia C L; Campiglia, Andres D

2012-07-06

The analytical performance of BEA - a commercial zeolite - is evaluated for the pre-concentration of fifteen Environmental Protection Agency - polycyclic aromatic hydrocarbons and their subsequent HPLC analysis in tap and lake water samples. The pre-concentration factors obtained with BEA have led to a method with excellent analytical figures of merit. One milliliter aliquots were sufficient to obtain excellent precision of measurements at the parts-per-trillion concentration level with relative standard deviations varying from 4.1% (dibenzo[a,h]anthracene) to 13.4% (pyrene). The limits of detection were excellent as well and varied between 1.1 (anthracene) and 49.9 ng L(-1) (indeno[1,2,3-cd]pyrene). The recovery values of all the studied compounds meet the criterion for regulated polycyclic aromatic hydrocarbons, which mandates relative standard deviations equal or lower than 25%. The small volume of organic solvents (100 μL per sample) and amount of BEA (2 mg per sample) makes sample pre-concentration environmentally friendly and cost effective. The extraction procedure is well suited for numerous samples as the small working volume (1 mL) facilitates the implementation of simultaneous sample extraction. These are attractive features when routine monitoring of numerous samples is contemplated. Copyright © 2012 Elsevier B.V. All rights reserved.

Aquatic concentrations of chemical analytes compared to ecotoxicity estimates

Data.gov (United States)

U.S. Environmental Protection Agency — We describe screening level estimates of potential aquatic toxicity posed by 227 chemical analytes that were measured in 25 ambient water samples collected as part...

Micro-evaporation electrolyte concentrator

NARCIS (Netherlands)

Timmer, B.H.; van Delft, K.M.; Olthuis, Wouter; Bergveld, Piet; van den Berg, Albert

2003-01-01

The sensitivity of miniaturized chemical analysis systems depends most of the time on the obtainable detection limit. Concentrating the analyte prior to the detection system can enhance the detection limit. In this writing an analyte concentrator is presented that makes use of evaporation to

Changes in concentrations of perfluorinated compounds, polybrominated diphenyl ethers, and polychlorinated biphenyls in Norwegian breast-milk during twelve months of lactation.

Science.gov (United States)

Thomsen, Cathrine; Haug, Line S; Stigum, Hein; Frøshaug, May; Broadwell, Sharon L; Becher, Georg

2010-12-15

At present, scientific knowledge on depuration rates of persistent organic pollutants (POPs) is limited and the previous assumptions of considerable reduction of body burdens through breast-feeding have recently been challenged. We therefore studied elimination rates of important POPs in nine Norwegian primiparous mothers and one mother breast-feeding her second child by collecting breast-milk samples (n = 70) monthly from about two weeks to up to twelve months after birth. Perfluorinated compounds (PFCs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and polychlorinated biphenyls (PCBs) were determined in the breast-milk samples. Linear mixed effect models were established for selected compounds, and significant decreases in the range of 1.2-4.7% in breast-milk concentrations per month were observed for a wide range of PCBs and PBDEs. For the first time, depuration rates for perfluorooctylsulfonate (PFOS) and perfluorooctanoic acid (PFOA) are presented, being 3.8 and 7.8% per month, respectively (p changes during the lactation period. After a year of nursing the breast-milk concentrations of PFCs, PBDEs, and PCBs were reduced by 15-94%.

The impact of monthly variation of the Pacific–North America (PNA teleconnection pattern on wintertime surface-layer aerosol concentrations in the United States

Directory of Open Access Journals (Sweden)

J. Feng

2016-04-01

Full Text Available The Pacific–North America teleconnection (PNA is the leading general circulation pattern in the troposphere over the region of North Pacific to North America during wintertime. This study examined the impacts of monthly variations of the PNA phase (positive or negative phase on wintertime surface-layer aerosol concentrations in the United States (US by analyzing observations during 1999–2013 from the Air Quality System of the Environmental Protection Agency (EPA-AQS and the model results for 1986–2006 from the global three-dimensional Goddard Earth Observing System (GEOS chemical transport model (GEOS-Chem. The composite analyses on the EPA-AQS observations over 1999–2013 showed that the average concentrations of PM2.5, sulfate, nitrate, ammonium, organic carbon, and black carbon aerosols over the US were higher in the PNA positive phases (25 % of the winter months examined, and this fraction of months had the highest positive PNA index values than in the PNA negative phases (25 % of the winter months examined, and this fraction of months had the highest negative PNA index values by 1.0 µg m−3 (8.7 %, 0.01 µg m−3 (0.5 %, 0.3 µg m−3 (29.1 %, 0.1 µg m−3 (11.9 %, 0.6 µg m−3 (13.5 %, and 0.2 µg m−3 (27.8 %, respectively. The simulated geographical patterns of the differences in concentrations of all aerosol species between the PNA positive and negative phases were similar to observations. Based on the GEOS-Chem simulation, the pattern correlation coefficients were calculated to show the impacts of PNA-induced variations in meteorological fields on aerosol concentrations. The PNA phase was found (i to influence sulfate concentrations mainly through changes in planetary boundary layer height (PBLH, precipitation (PR, and temperature; (ii to influence nitrate concentrations mainly through changes in temperature; and (iii to influence concentrations of ammonium, organic carbon, and black

An analytical/numerical correlation study of the multiple concentric cylinder model for the thermoplastic response of metal matrix composites

Science.gov (United States)

Pindera, Marek-Jerzy; Salzar, Robert S.; Williams, Todd O.

1993-01-01

The utility of a recently developed analytical micromechanics model for the response of metal matrix composites under thermal loading is illustrated by comparison with the results generated using the finite-element approach. The model is based on the concentric cylinder assemblage consisting of an arbitrary number of elastic or elastoplastic sublayers with isotropic or orthotropic, temperature-dependent properties. The elastoplastic boundary-value problem of an arbitrarily layered concentric cylinder is solved using the local/global stiffness matrix formulation (originally developed for elastic layered media) and Mendelson's iterative technique of successive elastic solutions. These features of the model facilitate efficient investigation of the effects of various microstructural details, such as functionally graded architectures of interfacial layers, on the evolution of residual stresses during cool down. The available closed-form expressions for the field variables can readily be incorporated into an optimization algorithm in order to efficiently identify optimal configurations of graded interfaces for given applications. Comparison of residual stress distributions after cool down generated using finite-element analysis and the present micromechanics model for four composite systems with substantially different temperature-dependent elastic, plastic, and thermal properties illustrates the efficacy of the developed analytical scheme.

EPA Monthly Key Performance Indicator Dashboards 2017

Science.gov (United States)

Each month, the Web Analytics Program posts updated Key Performance Indicator (KPI) dashboards that correspond to three Web performance goals: content consumption, content discovery, and audience engagement.

Median of patient results as a tool for assessment of analytical stability.

Science.gov (United States)

Jørgensen, Lars Mønster; Hansen, Steen Ingemann; Petersen, Per Hyltoft; Sölétormos, György

2015-06-15

In spite of the well-established external quality assessment and proficiency testing surveys of analytical quality performance in laboratory medicine, a simple tool to monitor the long-term analytical stability as a supplement to the internal control procedures is often needed. Patient data from daily internal control schemes was used for monthly appraisal of the analytical stability. This was accomplished by using the monthly medians of patient results to disclose deviations from analytical stability, and by comparing divergences with the quality specifications for allowable analytical bias based on biological variation. Seventy five percent of the twenty analytes achieved on two COBASs INTEGRA 800 instruments performed in accordance with the optimum and with the desirable specifications for bias. Patient results applied in analytical quality performance control procedures are the most reliable sources of material as they represent the genuine substance of the measurements and therefore circumvent the problems associated with non-commutable materials in external assessment. Patient medians in the monthly monitoring of analytical stability in laboratory medicine are an inexpensive, simple and reliable tool to monitor the steadiness of the analytical practice. Copyright © 2015 Elsevier B.V. All rights reserved.

Test set of gaseous analytes at Hanford tank farms

International Nuclear Information System (INIS)

1997-01-01

DOE has stored toxic and radioactive waste materials in large underground tanks. When the vapors in the tank headspaces vent to the open atmosphere a potentially dangerous situation can occur for personnel in the area. An open-path atmospheric pollution monitor is being developed to monitor the open air space above these tanks. In developing this infrared spectra monitor as a safety alert instrument, it is important to know what hazardous gases, called the Analytes of Concern, are most likely to be found in dangerous concentrations. The monitor must consider other gases which could interfere with measurements of the Analytes of Concern. The total list of gases called the Test Set Analytes form the basis for testing the pollution monitor. Prior measurements in 54 tank headspaces have detected 102 toxic air pollutants (TAPs) and over 1000 other analytes. The hazardous Analytes are ranked herein by a Hazardous Atmosphere Rating which combines their measured concentration, their density relative to air, and the concentration at which they become dangerous. The top 20 toxic air pollutants, as ranked by the Hazardous Atmosphere Rating, and the top 20 other analytes, in terms of measured concentrations, are analyzed for possible inclusion in the Test Set Analytes. Of these 40 gases, 20 are selected. To these 20 gases are added the 6 omnipresent atmospheric gases with the highest concentrations, since their spectra could interfere with measurements of the other spectra. The 26 Test Set Analytes are divided into a Primary Set and a Secondary Set. The Primary Set, gases which must be detectable by the monitor, includes the 6 atmospheric gases and the 6 hazardous gases which have been measured at dangerous concentrations. The Secondary Set gases need not be monitored at this time. The infrared spectra indicates that the pollution monitor will detect all 26 Test Set Analytes by thermal emission and will detect 15 Test Set Analytes by laser absorption

Forensic analysis of high explosives residues in post-blast water samples employing solid phase extraction for analyte pro-concentration

International Nuclear Information System (INIS)

Umi Kalsom Ahmad; Rajendran, Sumathy; Ling, Lee Woan

2008-01-01

Nitro aromatic, nitramine and nitrate ester compounds are a major group of high order explosive or better known as military explosives. Octahydro-1,3,5,7-tetrazocine (HMX), 1,3,5-hexahydro-1,3,5-trinitro triazine (RDX), 2,4,6-trinitro-toluene (TNT), pentaerythritol tetranitrate (PETN) and 2,4-dinitrotoluene (2,4-DNT) are secondary high explosives classified as most commonly used explosives components. There is an increasing demand for pre-concentration of these compounds in water samples as the sensitivity achieved by instrumental analytical methods for these high explosives residues are the main drawback in the application at trace levels for forensic analysis. Hence, a simple cartridge solid phase extraction (SPE) procedure was optimized as the off-line extraction and pre-concentration method to enhance the detection limit of high explosive residues using micellar electrokinetic chromatography (MEKC) and gas chromatography with electron-capture detection (GC-ECD) methods. The SPE cartridges utilized LiChrolut EN as the SPE adsorbent. By emplying pre-concentration using SPE, the detection limits of the target analytes in water sample were lowered by more than 1000 times with good percentage recovery (>87%) for MEKC method and lowered by 120 times with more than 2 % percentage recovery for GC-ECD methods. In order to test the feasibility of the developed method to real cases, post-blast water samples were analyzed. The post-blast water samples which were collected from Baling Bom training range, Ulu Kinta, Perak contained RDX and PETN in the range of 0.05 - 0.17 ppm and 0.0124 - 0.0390 ppm respectively. (author)

Median of patient results as a tool for assessment of analytical stability

DEFF Research Database (Denmark)

Jørgensen, Lars Mønster; Hansen, Steen Ingemann; Petersen, Per Hyltoft

2015-01-01

BACKGROUND: In spite of the well-established external quality assessment and proficiency testing surveys of analytical quality performance in laboratory medicine, a simple tool to monitor the long-term analytical stability as a supplement to the internal control procedures is often needed. METHOD......: Patient data from daily internal control schemes was used for monthly appraisal of the analytical stability. This was accomplished by using the monthly medians of patient results to disclose deviations from analytical stability, and by comparing divergences with the quality specifications for allowable...... analytical bias based on biological variation. RESULTS: Seventy five percent of the twenty analytes achieved on two COBASs INTEGRA 800 instruments performed in accordance with the optimum and with the desirable specifications for bias. DISCUSSION: Patient results applied in analytical quality performance...

Monthly variation in faeces:blood concentration ratio of persistent organic pollutants over the first year of life: a case study of one infant

International Nuclear Information System (INIS)

Chen, Yiqin; McLachlan, Michael S.; Kaserzon, Sarit; Wang, Xianyu; Weijs, Liesbeth; Gallen, Michael; Toms, Leisa-Maree L.; Li, Yan; Aylward, Lesa L.; Sly, Peter D.; Mueller, Jochen F.

2016-01-01

Previous studies have found that the concentrations of a range of persistent organic pollutants (POPs) in faeces is linearly proportional to the POP concentrations in blood of human adults irrespective of age and gender. In order to investigate the correlation between POP concentrations in faeces and blood in infants, the monthly variation of POP concentrations in faeces over the first year of life of one infant was investigated in this study and compared to modelled blood concentrations. Faecal samples were collected from one male infant daily. The samples were pooled by month and analysed for three selected POPs (2,2 ′ ,4,4 ′ ,5,5 ′ -Hexachlorobiphenyl (PCB153), p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) and 2,2 ′ ,4,4′-tetrabromodiphenyl ether (BDE47)). The POP concentrations in faecal samples increased for the first four months by a factor of 2.9, 4.9 and 1.4 for PCB153, BDE47, and p,p′-DDE, respectively. The faecal concentrations of all POPs decreased rapidly following the introduction of formula and solid food to the diet and subsequent weaning of the infant. Further, a one-compartment model was developed to estimate the daily POP concentrations in the blood of the infant. The POP concentrations in blood were predicted to vary much less over the first year than those observed in faeces. The faeces:blood concentration ratio of selected POPs (K fb ) differed significantly (P<0.0001) between the period before and after weaning, and observed changes in K fb are far greater than the uncertainty in the estimated K fb . A more stable K fb after weaning indicates the possibility of applying the stable K fb values for non-invasive assessment of internal exposure in infants after weaning. The intra-individual variation in K fb in infants is worthy of further investigation. - Highlights: • Measured POPs concentrations in faecal samples decreased rapidly following weaning. • Ratio of faecal:blood concentrations (K fb ) changed over the first

Two-dimensional analytical solutions for chemical transport in aquifers. Part 1. Simplified solutions for sources with constant concentration. Part 2. Exact solutions for sources with constant flux rate

International Nuclear Information System (INIS)

Shan, C.; Javandel, I.

1996-05-01

Analytical solutions are developed for modeling solute transport in a vertical section of a homogeneous aquifer. Part 1 of the series presents a simplified analytical solution for cases in which a constant-concentration source is located at the top (or the bottom) of the aquifer. The following transport mechanisms have been considered: advection (in the horizontal direction), transverse dispersion (in the vertical direction), adsorption, and biodegradation. In the simplified solution, however, longitudinal dispersion is assumed to be relatively insignificant with respect to advection, and has been neglected. Example calculations are given to show the movement of the contamination front, the development of concentration profiles, the mass transfer rate, and an application to determine the vertical dispersivity. The analytical solution developed in this study can be a useful tool in designing an appropriate monitoring system and an effective groundwater remediation method

The development of precisely analytical method for the concentrated boric acid solution in the NPP systems

Energy Technology Data Exchange (ETDEWEB)

Sung, G. B.; Jung, K. H.; Kang, D. W. [KEPRI, Taejon (Korea, Republic of); Park, C. S. [KEPCO, Taejon (Korea, Republic of)

1999-05-01

Boric acid is used for reactivity control in nuclear reactors, which frequently results in leftover boric acid. This extra boric acid is stored in boric acid storage tank after the concentration process by boric acid evaporator. Apart from this excess, highly concentrated boric acid is stored in safety-related boric acid storage tank. Accordingly, proper maintenance of these boric acid is one of the greatest safety concerns. The solubility of boric acid decreases with decreasing temperature resulting in its precipitation. Consequently, the temperature of boric acid storage tanks is maintained at high temperature. The following analysis should be also performed at the similar temperature to prevent the formation of boric acid precipitation, which is difficult to achieve affecting the accuracy of analytical results. This paper presents a new sampling and measuring technique that makes up for the difficulties mentioned above and shows several advantages including improved reliability and short analysis time. This method is based on gravimetry and dilution method and is expected to be widely used in field application.

Analytical procedure for experimental quantification of carrier concentration in semiconductor devices by using electric scanning probe microscopy

International Nuclear Information System (INIS)

Fujita, Takaya; Matsumura, Koji; Itoh, Hiroshi; Fujita, Daisuke

2014-01-01

Scanning capacitance microscopy (SCM) is based on a contact-mode variant of atomic force microscopy, which is used for imaging two-dimensional carrier (electrons and holes) distributions in semiconductor devices. We introduced a method of quantification of the carrier concentration by experimentally deduced calibration curves, which were prepared for semiconductor materials such as silicon and silicon carbide. The analytical procedure was circulated to research organizations in a round-robin test. The effectiveness of the method was confirmed for practical analysis and for what is expected for industrial pre-standardization from the viewpoint of comparability among users. It was also applied to other electric scanning probe microscopy techniques such as scanning spreading resistance microscopy and scanning nonlinear dielectric microscopy. Their depth profiles of carrier concentration were found to be in good agreement with those characterized by SCM. These results suggest that our proposed method will be compatible with future next-generation microscopy. (paper)

Monthly variation in faeces:blood concentration ratio of persistent organic pollutants over the first year of life: a case study of one infant

Energy Technology Data Exchange (ETDEWEB)

Chen, Yiqin, E-mail: y.chen16@uq.edu.au [The University of Queensland, National Research Centre for Environmental Toxicology (Australia); McLachlan, Michael S. [Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University (Sweden); Kaserzon, Sarit; Wang, Xianyu; Weijs, Liesbeth; Gallen, Michael [The University of Queensland, National Research Centre for Environmental Toxicology (Australia); Toms, Leisa-Maree L. [School of Public Health and Social Work and Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology (Australia); Li, Yan [The University of Queensland, National Research Centre for Environmental Toxicology (Australia); Aylward, Lesa L. [The University of Queensland, National Research Centre for Environmental Toxicology (Australia); Summit Toxicology, LLP, Falls Church, VA (United States); Sly, Peter D. [Children’s Health and Environment Program, Queensland Children’s Medical Research Institute, Brisbane (Australia); Child Health Research Centre, The University of Queensland (Australia); Mueller, Jochen F. [The University of Queensland, National Research Centre for Environmental Toxicology (Australia)

2016-05-15

Previous studies have found that the concentrations of a range of persistent organic pollutants (POPs) in faeces is linearly proportional to the POP concentrations in blood of human adults irrespective of age and gender. In order to investigate the correlation between POP concentrations in faeces and blood in infants, the monthly variation of POP concentrations in faeces over the first year of life of one infant was investigated in this study and compared to modelled blood concentrations. Faecal samples were collected from one male infant daily. The samples were pooled by month and analysed for three selected POPs (2,2{sup ′},4,4{sup ′},5,5{sup ′}-Hexachlorobiphenyl (PCB153), p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) and 2,2{sup ′},4,4′-tetrabromodiphenyl ether (BDE47)). The POP concentrations in faecal samples increased for the first four months by a factor of 2.9, 4.9 and 1.4 for PCB153, BDE47, and p,p′-DDE, respectively. The faecal concentrations of all POPs decreased rapidly following the introduction of formula and solid food to the diet and subsequent weaning of the infant. Further, a one-compartment model was developed to estimate the daily POP concentrations in the blood of the infant. The POP concentrations in blood were predicted to vary much less over the first year than those observed in faeces. The faeces:blood concentration ratio of selected POPs (K{sub fb}) differed significantly (P<0.0001) between the period before and after weaning, and observed changes in K{sub fb} are far greater than the uncertainty in the estimated K{sub fb}. A more stable K{sub fb} after weaning indicates the possibility of applying the stable K{sub fb} values for non-invasive assessment of internal exposure in infants after weaning. The intra-individual variation in K{sub fb} in infants is worthy of further investigation. - Highlights: • Measured POPs concentrations in faecal samples decreased rapidly following weaning. • Ratio of faecal

An analytical model for nanoparticles concentration resulting from infusion into poroelastic brain tissue.

Science.gov (United States)

Pizzichelli, G; Di Michele, F; Sinibaldi, E

2016-02-01

We consider the infusion of a diluted suspension of nanoparticles (NPs) into poroelastic brain tissue, in view of relevant biomedical applications such as intratumoral thermotherapy. Indeed, the high impact of the related pathologies motivates the development of advanced therapeutic approaches, whose design also benefits from theoretical models. This study provides an analytical expression for the time-dependent NPs concentration during the infusion into poroelastic brain tissue, which also accounts for particle binding onto cells (by recalling relevant results from the colloid filtration theory). Our model is computationally inexpensive and, compared to fully numerical approaches, permits to explicitly elucidate the role of the involved physical aspects (tissue poroelasticity, infusion parameters, NPs physico-chemical properties, NP-tissue interactions underlying binding). We also present illustrative results based on parameters taken from the literature, by considering clinically relevant ranges for the infusion parameters. Moreover, we thoroughly assess the model working assumptions besides discussing its limitations. While not laying any claims of generality, our model can be used to support the development of more ambitious numerical approaches, towards the preliminary design of novel therapies based on NPs infusion into brain tissue. Copyright © 2015 Elsevier Inc. All rights reserved.

Nuclear analytical methods for platinum group elements

International Nuclear Information System (INIS)

2005-04-01

Platinum group elements (PGE) are of special interest for analytical research due to their economic importance like chemical peculiarities as catalysts, medical applications as anticancer drugs, and possible environmental detrimental impact as exhaust from automobile catalyzers. Natural levels of PGE are so low in concentration that most of the current analytical techniques approach their limit of detection capacity. In addition, Ru, Rh, Pd, Re, Os, Ir, and Pt analyses still constitute a challenge in accuracy and precision of quantification in natural matrices. Nuclear analytical techniques, such as neutron activation analysis, X ray fluorescence, or proton-induced X ray emission (PIXE), which are generally considered as reference methods for many analytical problems, are useful as well. However, due to methodological restrictions, they can, in most cases, only be applied after pre-concentration and under special irradiation conditions. This report was prepared following a coordinated research project and a consultants meeting addressing the subject from different viewpoints. The experts involved suggested to discuss the issue according to the (1) application, hence, the concentration levels encountered, and (2) method applied for analysis. Each of the different fields of application needs special consideration for sample preparation, PGE pre-concentration, and determination. Additionally, each analytical method requires special attention regarding the sensitivity and sample type. Quality assurance/quality control aspects are considered towards the end of the report. It is intended to provide the reader of this publication with state-of-the-art information on the various aspects of PGE analysis and to advise which technique might be most suitable for a particular analytical problem related to platinum group elements. In particular, many case studies described in detail from the authors' laboratory experience might help to decide which way to go. As in many cases

Two-dimensional analytical model of a proton exchange membrane fuel cell

International Nuclear Information System (INIS)

Liu, Jia Xing; Guo, Hang; Ye, Fang; Ma, Chong Fang

2017-01-01

In this study, a two-dimensional full cell analytical model of a proton exchange membrane fuel cell is developed. The analytical model describes electrochemical reactions on the anode and cathode catalyst layer, reactants diffusion in the gas diffusion layer, and gases flow in the gas channel, etc. The analytical solution is derived according to the basic physical equations. The performance predicted by the model is in good agreement with the experimental data. The results show that the polarization mainly occurs in the cathode side of the proton exchange membrane fuel cell. The anodic overpotential cannot be neglected. The hydrogen and oxygen concentrations decrease along the channel flow direction. The hydrogen and oxygen concentrations in the catalyst layer decrease with the current density. As predicted by the model, concentration polarization mainly occurs in the cathode side. - Highlights: • A 2D full cell analytical model of a proton exchange membrane fuel cell is developed. • The analytical solution is deduced according to the basic equations. • The anode overpotential is not so small that it cannot be neglected. • Species concentration distributions in the fuel cell is obtained and analyzed.

Analytical performance, reference values and decision limits. A need to differentiate between reference intervals and decision limits and to define analytical quality specifications

DEFF Research Database (Denmark)

Petersen, Per Hyltoft; Jensen, Esther A; Brandslund, Ivan

2012-01-01

of the values of analytical components measured on reference samples from reference individuals. Decision limits are based on guidelines from national and international expert groups defining specific concentrations of certain components as limits for decision about diagnosis or well-defined specific actions....... Analytical quality specifications for reference intervals have been defined for bias since the 1990s, but in the recommendations specified in the clinical guidelines analytical quality specifications are only scarcely defined. The demands for negligible biases are, however, even more essential for decision...... limits, as the choice is no longer left to the clinician, but emerge directly from the concentration. Even a small bias will change the number of diseased individuals, so the demands for negligible biases are obvious. A view over the analytical quality as published gives a variable picture of bias...

Radiocesium concentrations in epigeic earthworms at various distances from the Fukushima Nuclear Power Plant 6 months after the 2011 accident.

Science.gov (United States)

Hasegawa, Motohiro; Ito, Masamichi T; Kaneko, Shinji; Kiyono, Yoshiyuki; Ikeda, Shigeto; Makino, Shun'ichi

2013-12-01

We investigated the concentrations of radiocesium in epigeic earthworms, litter, and soil samples collected from forests in Fukushima Prefecture 6 months after the Fukushima Dai-ichi Nuclear Power Plant accident in 2011. Radiocesium concentrations in litter accumulated on the forest floor were higher than those in the soil (0-5 cm depth). The highest average (134+137)Cs concentrations in earthworms (approximately 19 Bq g(-1) of wet weight with gut contents and 108 Bq g(-1) of dry weight without gut contents) were recorded from a plot that experienced an air dose rate of 3.1 μSv h(-1), and earthworm concentrations were found to increase with litter and/or soil concentrations. Average (134)Cs and (137)Cs concentrations (with or without gut contents) were intermediate between accumulated litter and soil. Different species in the same ecological groups on the same plots had similar concentrations because of their use of the same habitats or their similar physiological characteristics. The contribution of global fallout (137)Cs to earthworms with gut contents was calculated to be very low, and most (137)Cs in earthworms was derived from the Fukushima accident. Transfer factors from accumulated litter to earthworms, based on their dry weights, ranged from 0.21 to 0.35, in agreement with previous field studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

Modeling microelectrode biosensors: free-flow calibration can substantially underestimate tissue concentrations.

Science.gov (United States)

Newton, Adam J H; Wall, Mark J; Richardson, Magnus J E

2017-03-01

Microelectrode amperometric biosensors are widely used to measure concentrations of analytes in solution and tissue including acetylcholine, adenosine, glucose, and glutamate. A great deal of experimental and modeling effort has been directed at quantifying the response of the biosensors themselves; however, the influence that the macroscopic tissue environment has on biosensor response has not been subjected to the same level of scrutiny. Here we identify an important issue in the way microelectrode biosensors are calibrated that is likely to have led to underestimations of analyte tissue concentrations. Concentration in tissue is typically determined by comparing the biosensor signal to that measured in free-flow calibration conditions. In a free-flow environment the concentration of the analyte at the outer surface of the biosensor can be considered constant. However, in tissue the analyte reaches the biosensor surface by diffusion through the extracellular space. Because the enzymes in the biosensor break down the analyte, a density gradient is set up resulting in a significantly lower concentration of analyte near the biosensor surface. This effect is compounded by the diminished volume fraction (porosity) and reduction in the diffusion coefficient due to obstructions (tortuosity) in tissue. We demonstrate this effect through modeling and experimentally verify our predictions in diffusive environments. NEW & NOTEWORTHY Microelectrode biosensors are typically calibrated in a free-flow environment where the concentrations at the biosensor surface are constant. However, when in tissue, the analyte reaches the biosensor via diffusion and so analyte breakdown by the biosensor results in a concentration gradient and consequently a lower concentration around the biosensor. This effect means that naive free-flow calibration will underestimate tissue concentration. We develop mathematical models to better quantify the discrepancy between the calibration and tissue

Radiocesium concentrations in epigeic earthworms at various distances from the Fukushima Nuclear Power Plant 6 months after the 2011 accident

International Nuclear Information System (INIS)

Hasegawa, Motohiro; Ito, Masamichi T.; Kaneko, Shinji; Kiyono, Yoshiyuki; Ikeda, Shigeto; Makino, Shun'ichi

2013-01-01

We investigated the concentrations of radiocesium in epigeic earthworms, litter, and soil samples collected from forests in Fukushima Prefecture 6 months after the Fukushima Dai-ichi Nuclear Power Plant accident in 2011. Radiocesium concentrations in litter accumulated on the forest floor were higher than those in the soil (0–5 cm depth). The highest average 134+137 Cs concentrations in earthworms (approximately 19 Bq g −1 of wet weight with gut contents and 108 Bq g −1 of dry weight without gut contents) were recorded from a plot that experienced an air dose rate of 3.1 μSv h −1 , and earthworm concentrations were found to increase with litter and/or soil concentrations. Average 134 Cs and 137 Cs concentrations (with or without gut contents) were intermediate between accumulated litter and soil. Different species in the same ecological groups on the same plots had similar concentrations because of their use of the same habitats or their similar physiological characteristics. The contribution of global fallout 137 Cs to earthworms with gut contents was calculated to be very low, and most 137 Cs in earthworms was derived from the Fukushima accident. Transfer factors from accumulated litter to earthworms, based on their dry weights, ranged from 0.21 to 0.35, in agreement with previous field studies. -- Highlights: • Radiocesium concentrations in earthworms were intermediate between litter and soil. • Three earthworm species in epigeic groups had similar radiocesium concentrations. • Transfer factors from accumulated litter to earthworms ranged from 0.21 to 0.35

Optical characterization of nonimaging dish concentrator for the application of dense-array concentrator photovoltaic system.

Science.gov (United States)

Tan, Ming-Hui; Chong, Kok-Keong; Wong, Chee-Woon

2014-01-20

Optimization of the design of a nonimaging dish concentrator (NIDC) for a dense-array concentrator photovoltaic system is presented. A new algorithm has been developed to determine configuration of facet mirrors in a NIDC. Analytical formulas were derived to analyze the optical performance of a NIDC and then compared with a simulated result obtained from a numerical method. Comprehensive analysis of optical performance via analytical method has been carried out based on facet dimension and focal distance of the concentrator with a total reflective area of 120 m2. The result shows that a facet dimension of 49.8 cm, focal distance of 8 m, and solar concentration ratio of 411.8 suns is the most optimized design for the lowest cost-per-output power, which is US$1.93 per watt.

Interference of ascorbic acid with chemical analytes.

Science.gov (United States)

Meng, Qing H; Irwin, William C; Fesser, Jennifer; Massey, K Lorne

2005-11-01

Ascorbic acid can interfere with methodologies involving redox reactions, while comprehensive studies on main chemistry analysers have not been reported. We therefore attempted to determine the interference of ascorbic acid with analytes on the Beckman Synchron LX20. Various concentrations of ascorbic acid were added to serum, and the serum analytes were measured on the LX20. With a serum ascorbic acid concentration of 12.0 mmol/L, the values for sodium, potassium, calcium and creatinine increased by 43%, 58%, 103% and 26%, respectively (Pascorbic acid concentration of 12.0 mmol/L, the values for chloride, total bilirubin and uric acid decreased by 33%, 62% and 83%, respectively (Pcholesterol, triglyceride, ammonia and lactate. There was no definite influence of ascorbic acid on analytical values for total CO(2), urea, glucose, phosphate, total protein, albumin, amylase, creatine kinase, creatine kinase-MB, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total iron, unbound iron-binding capacity or magnesium. Ascorbic acid causes a false increase in sodium, potassium, calcium and creatinine results and a false decrease in chloride, total bilirubin, uric acid, total cholesterol, triglyceride, ammonia and lactate results.

Quantification of Concentration of Microalgae Anabaena Cylindrica, Coal-bed Methane Water Isolates Nannochloropsis Gaditana and PW-95 in Aquatic Solutions through Hyperspectral Reflectance Measurement and Analytical Model Establishment

Science.gov (United States)

Zhou, Z.; Zhou, X.; Apple, M. E.; Spangler, L.

2017-12-01

Three species of microalgae, Anabaena cylindrica (UTEX # 1611), coal-bed methane water isolates Nannochloropsis gaditana and PW-95 were cultured for the measurements of their hyperspectral profiles in different concentrations. The hyperspectral data were measured by an Analytical Spectral Devices (ASD) spectroradiomter with the spectral resolution of 1 nanometer over the wavelength ranges from 350nm to 1050 nm for samples of microalgae of different concentration. Concentration of microalgae was measured using a Hemocytometer under microscope. The objective of this study is to establish the relation between spectral reflectance and micro-algal concentration so that microalgae concentration can be measured remotely by space- or airborne hyperspectral or multispectral sensors. Two types of analytical models, linear reflectance-concentration model and Lamber-Beer reflectance-concentration model, were established for each species. For linear modeling, the wavelength with the maximum correlation coefficient between the reflectance and concentrations of algae was located and then selected for each species of algae. The results of the linear models for each species are shown in Fig.1(a), in which Refl_1, Refl_2, and Refl_3 represent the reflectance of Anabaena, N. Gaditana, and PW-95 respectively. C1, C2, and C3 represent the Concentrations of Anabaena, N. Gaditana, and PW-95 respectively. The Lamber-Beer models were based on the Lambert-Beer Law, which states that the intensity of light propagating in a substance dissolved in a fully transmitting solvent is directly proportional to the concentration of the substance and the path length of the light through the solution. Thus, for the Lamber-Beer modeling, a wavelength with large absorption in red band was selected for each species. The results of Lambert-Beer models for each species are shown in Fig.1(b). Based on the Lamber-Beer models, the absorption coefficient for the three different species will be quantified.

Studies on application of neutron activation analysis -Applied research on air pollution monitoring and development of analytical method of environmental samples

International Nuclear Information System (INIS)

Chung, Yong Sam; Moon, Jong Hwa; Chung, Young Ju; Jeong, Eui Sik; Lee, Sang Mi; Kang, Sang Hun; Cho, Seung Yeon; Kwon, Young Sik; Chung, Sang Wuk; Lee, Kyu Sung; Chun, Ki Hong; Kim, Nak Bae; Lee, Kil Yong; Yoon, Yoon Yeol; Chun, Sang Ki.

1997-09-01

This research report is written for results of applied research on air pollution monitoring using instrumental neutron activation analysis. For identification and standardization of analytical method, 24 environmental samples are analyzed quantitatively, and accuracy and precision of this method are measured. Using airborne particulate matter and biomonitor chosen as environmental indicators, trace elemental concentrations of sample collected at urban and rural site monthly are determined ant then the calculation of statistics and the factor analysis are carried out for investigation of emission source. Facilities for NAA are installed in a new HANARO reactor, functional test is performed for routine operation. In addition, unified software code for NAA is developed to improve accuracy, precision and abilities of analytical processes. (author). 103 refs., 61 tabs., 19 figs

Application of spectrophotometry for determination of analytes in high percentage levels

International Nuclear Information System (INIS)

Koteswara Rao, M.; Ram Mohan, Vijaya; Yadav, R.B.

2009-01-01

This paper describes the application of differential Spectrophotometry for the determination of analytes in high concentration levels unlike the conventional photometric methods that are useful for measuring concentration at trace levels. Differential spectrophotometry is based on measuring the absorbance of the test solution against a standard of accurately known concentration instead of a reagent blank or pure solvent. In this way, the error in measurement is confined to the difference in the two concentrations and is minimized. Thus the error is much smaller than in conventional Spectrophotometry, which therefore allows its application for determining analytes in major concentration. This method was applied for the assay of Niobium and Titanium used as strategic materials in various field. (author)

A Synthesis of Light Absorption Properties of the Arctic Ocean: Application to Semi-analytical Estimates of Dissolved Organic Carbon Concentrations from Space

Science.gov (United States)

Matsuoka, A.; Babin, M.; Doxaran, D.; Hooker, S. B.; Mitchell, B. G.; Belanger, S.; Bricaud, A.

2014-01-01

The light absorption coefficients of particulate and dissolved materials are the main factors determining the light propagation of the visible part of the spectrum and are, thus, important for developing ocean color algorithms. While these absorption properties have recently been documented by a few studies for the Arctic Ocean [e.g., Matsuoka et al., 2007, 2011; Ben Mustapha et al., 2012], the datasets used in the literature were sparse and individually insufficient to draw a general view of the basin-wide spatial and temporal variations in absorption. To achieve such a task, we built a large absorption database at the pan-Arctic scale by pooling the majority of published datasets and merging new datasets. Our results showed that the total non-water absorption coefficients measured in the Eastern Arctic Ocean (EAO; Siberian side) are significantly higher 74 than in the Western Arctic Ocean (WAO; North American side). This higher absorption is explained 75 by higher concentration of colored dissolved organic matter (CDOM) in watersheds on the Siberian 76 side, which contains a large amount of dissolved organic carbon (DOC) compared to waters off 77 North America. In contrast, the relationship between the phytoplankton absorption (a()) and chlorophyll a (chl a) concentration in the EAO was not significantly different from that in the WAO. Because our semi-analytical CDOM absorption algorithm is based on chl a-specific a() values [Matsuoka et al., 2013], this result indirectly suggests that CDOM absorption can be appropriately erived not only for the WAO but also for the EAO using ocean color data. Derived CDOM absorption values were reasonable compared to in situ measurements. By combining this algorithm with empirical DOC versus CDOM relationships, a semi-analytical algorithm for estimating DOC concentrations for coastal waters at the Pan-Arctic scale is presented and applied to satellite ocean color data.

Analytical validation of an ultraviolet-visible procedure for determining lutein concentration and application to lutein-loaded nanoparticles.

Science.gov (United States)

Silva, Jéssica Thaís do Prado; Silva, Anderson Clayton da; Geiss, Julia Maria Tonin; de Araújo, Pedro Henrique Hermes; Becker, Daniela; Bracht, Lívia; Leimann, Fernanda Vitória; Bona, Evandro; Guerra, Gustavo Petri; Gonçalves, Odinei Hess

2017-09-01

Lutein is a carotenoid presenting known anti-inflammatory and antioxidant properties. Lutein-rich diets have been associated with neurological improvement as well as reduction of the risk of vision loss due to Age-Related Macular Degeneration (AMD). Micro and nanoencapsulation have demonstrated to be effective techniques in protecting lutein against degradation and also in improving its bioavailability. However, actual lutein concentration inside the capsules and encapsulation efficiency are key parameters that must be precisely known when designing in vitro and in vivo tests. In this work an analytical procedure was validated for the determination of the actual lutein content in zein nanoparticles using ultraviolet-visible spectroscopy. Method validation followed the International Conference on Harmonisation (ICH) guidelines which evaluate linearity, detection limit, quantification limit, accuracy and precision. The validated methodology was applied to characterize lutein-loaded nanoparticles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Trace detection of analytes using portable raman systems

Science.gov (United States)

Alam, M. Kathleen; Hotchkiss, Peter J.; Martin, Laura E.; Jones, David Alexander

2015-11-24

Apparatuses and methods for in situ detection of a trace amount of an analyte are disclosed herein. In a general embodiment, the present disclosure provides a surface-enhanced Raman spectroscopy (SERS) insert including a passageway therethrough, where the passageway has a SERS surface positioned therein. The SERS surface is configured to adsorb molecules of an analyte of interest. A concentrated sample is caused to flow over the SERS surface. The SERS insert is then provided to a portable Raman spectroscopy system, where it is analyzed for the analyte of interest.

Analytical results from salt batch 9 routine DSSHT and SEHT monthly samples

Energy Technology Data Exchange (ETDEWEB)

Peters, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-06-01

Strip Effluent Hold Tank (SEHT) and Decontaminated Salt Solution Hold Tank (DSSHT) samples from several of the “microbatches” of Integrated Salt Disposition Project (ISDP) Salt Batch (“Macrobatch”) 9 have been analyzed for ²³⁸Pu, ⁹⁰Sr, ¹³⁷Cs, cations (Inductively Coupled Plasma Emission Spectroscopy - ICPES), and anions (Ion Chromatography Anions - IC-A). The analytical results from the current microbatch samples are similar to those from previous macrobatch samples. The Cs removal continues to be acceptable, with decontamination factors (DF) averaging 25700 (107% RSD). The bulk chemistry of the DSSHT and SEHT samples do not show any signs of unusual behavior, other than lacking the anticipated degree of dilution that is calculated to occur during Modular Caustic-Side Solvent Extraction Unit (MCU) processing.

Prioritizing pesticide compounds for analytical methods development

Science.gov (United States)

Norman, Julia E.; Kuivila, Kathryn; Nowell, Lisa H.

2012-01-01

The U.S. Geological Survey (USGS) has a periodic need to re-evaluate pesticide compounds in terms of priorities for inclusion in monitoring and studies and, thus, must also assess the current analytical capabilities for pesticide detection. To meet this need, a strategy has been developed to prioritize pesticides and degradates for analytical methods development. Screening procedures were developed to separately prioritize pesticide compounds in water and sediment. The procedures evaluate pesticide compounds in existing USGS analytical methods for water and sediment and compounds for which recent agricultural-use information was available. Measured occurrence (detection frequency and concentrations) in water and sediment, predicted concentrations in water and predicted likelihood of occurrence in sediment, potential toxicity to aquatic life or humans, and priorities of other agencies or organizations, regulatory or otherwise, were considered. Several existing strategies for prioritizing chemicals for various purposes were reviewed, including those that identify and prioritize persistent, bioaccumulative, and toxic compounds, and those that determine candidates for future regulation of drinking-water contaminants. The systematic procedures developed and used in this study rely on concepts common to many previously established strategies. The evaluation of pesticide compounds resulted in the classification of compounds into three groups: Tier 1 for high priority compounds, Tier 2 for moderate priority compounds, and Tier 3 for low priority compounds. For water, a total of 247 pesticide compounds were classified as Tier 1 and, thus, are high priority for inclusion in analytical methods for monitoring and studies. Of these, about three-quarters are included in some USGS analytical method; however, many of these compounds are included on research methods that are expensive and for which there are few data on environmental samples. The remaining quarter of Tier 1

Analytical evaluation of the radionuclide concentration through the aquifer for the Abadia de Goias Repository

International Nuclear Information System (INIS)

Alves, Antonio Sergio de Martin

1999-01-01

In this paper the radionuclide concentration though the aquifer has been determined by an analytical process considering that the radionuclide migration is influenced by two kinds of radionuclides releases from the repository during an overflow. In the first release it is assumed that when the radionuclides reach the aquifer there is no contamination in it and the release rate is a constant. For this case it is utilized the model of Reference. For the subsequent releases there will be a contamination in the aquifer provenient from the former releases; it is considered that the subsequent releases are a function of the time which, for the Abadia de Goias Repository, was determined in the Reference. The Laplace transform Method has been utilized to solve the Radionuclide Migration Transport Equation in the aquifer region for the subsequent releases and the resulting function is expressed in terms of exponential and complementary error functions. The improvement in the calculation model, presented in this paper, can be used in the safety analysis of repositories, contributing thus in the nuclear waste management field and particularly, being connecting also to the environmental protection concern. (author)

ANALYTICAL SYNTHESIS OF CHEMICAL REACTOR CONTROL SYSTEM

Directory of Open Access Journals (Sweden)

Alexander Labutin

2017-02-01

Full Text Available The problem of the analytical synthesis of the synergetic control system of chemical reactor for the realization of a complex series-parallel exothermal reaction has been solved. The synthesis of control principles is performed using the analytical design method of aggregated regulators. Synthesized nonlinear control system solves the problem of stabilization of the concentration of target component at the exit of reactor and also enables one to automatically transfer to new production using the equipment.

A synthesis of light absorption properties of the Pan-Arctic Ocean: application to semi-analytical estimates of dissolved organic carbon concentrations from space

Science.gov (United States)

Matsuoka, A.; Babin, M.; Doxaran, D.; Hooker, S. B.; Mitchell, B. G.; Bélanger, S.; Bricaud, A.

2013-11-01

The light absorption coefficients of particulate and dissolved materials are the main factors determining the light propagation of the visible part of the spectrum and are, thus, important for developing ocean color algorithms. While these absorption properties have recently been documented by a few studies for the Arctic Ocean (e.g., Matsuoka et al., 2007, 2011; Ben Mustapha et al., 2012), the datasets used in the literature were sparse and individually insufficient to draw a general view of the basin-wide spatial and temporal variations in absorption. To achieve such a task, we built a large absorption database at the pan-Arctic scale by pooling the majority of published datasets and merging new datasets. Our results showed that the total non-water absorption coefficients measured in the Eastern Arctic Ocean (EAO; Siberian side) are significantly higher than in the Western Arctic Ocean (WAO; North American side). This higher absorption is explained by higher concentration of colored dissolved organic matter (CDOM) in watersheds on the Siberian side, which contains a large amount of dissolved organic carbon (DOC) compared to waters off North America. In contrast, the relationship between the phytoplankton absorption (aφ(λ)) and chlorophyll a (chl a) concentration in the EAO was not significantly different from that in the WAO. Because our semi-analytical CDOM absorption algorithm is based on chl a-specific aφ(λ) values (Matsuoka et al., 2013), this result indirectly suggests that CDOM absorption can be appropriately derived not only for the WAO but also for the EAO using ocean color data. Derived CDOM absorption values were reasonable compared to in situ measurements. By combining this algorithm with empirical DOC vs. CDOM relationships, a semi-analytical algorithm for estimating DOC concentrations for coastal waters at the Pan-Arctic scale is presented and applied to satellite ocean color data.

Long-Term Prediction of Satellite Orbit Using Analytical Method

Directory of Open Access Journals (Sweden)

Jae-Cheol Yoon

1997-12-01

Full Text Available A long-term prediction algorithm of geostationary orbit was developed using the analytical method. The perturbation force models include geopotential upto fifth order and degree and luni-solar gravitation, and solar radiation pressure. All of the perturbation effects were analyzed by secular variations, short-period variations, and long-period variations for equinoctial elements such as the semi-major axis, eccentricity vector, inclination vector, and mean longitude of the satellite. Result of the analytical orbit propagator was compared with that of the cowell orbit propagator for the KOREASAT. The comparison indicated that the analytical solution could predict the semi-major axis with an accuarcy of better than ~35meters over a period of 3 month.

Separate patient serum sodium medians from males and females provide independent information on analytical bias

DEFF Research Database (Denmark)

Hansen, Steen Ingemann; Petersen, Per Hyltoft; Lund, Flemming

2017-01-01

BACKGROUND: During monitoring of monthly medians of results from patients undertaken to assess analytical stability in routine laboratory performance, the medians for serum sodium for male and female patients were found to be significantly related. METHODS: Daily, weekly and monthly patient medians...... all instruments. CONCLUSIONS: The tight relationship between the gender medians for serum sodium is only possible when raw laboratory data are used for calculation. The two patient medians can be used to confirm both and are useful as independent estimates of analytical bias during constant...... calibration periods. In contrast to the gender combined median, the estimate of analytical bias can be confirmed further by calculation of the ratios of medians for males and females....

Numerical simulation and experimental validation of the three-dimensional flow field and relative analyte concentration distribution in an atmospheric pressure ion source.

Science.gov (United States)

Poehler, Thorsten; Kunte, Robert; Hoenen, Herwart; Jeschke, Peter; Wissdorf, Walter; Brockmann, Klaus J; Benter, Thorsten

2011-11-01

In this study, the validation and analysis of steady state numerical simulations of the gas flows within a multi-purpose ion source (MPIS) are presented. The experimental results were obtained with particle image velocimetry (PIV) measurements in a non-scaled MPIS. Two-dimensional time-averaged velocity and turbulent kinetic energy distributions are presented for two dry gas volume flow rates. The numerical results of the validation simulations are in very good agreement with the experimental data. All significant flow features have been correctly predicted within the accuracy of the experiments. For technical reasons, the experiments were conducted at room temperature. Thus, numerical simulations of ionization conditions at two operating points of the MPIS are also presented. It is clearly shown that the dry gas volume flow rate has the most significant impact on the overall flow pattern within the APLI source; far less critical is the (larger) nebulization gas flow. In addition to the approximate solution of Reynolds-Averaged Navier-Stokes equations, a transport equation for the relative analyte concentration has been solved. The results yield information on the three-dimensional analyte distribution within the source. It becomes evident that for ion transport into the MS ion transfer capillary, electromagnetic forces are at least as important as fluid dynamic forces. However, only the fluid dynamics determines the three-dimensional distribution of analyte gas. Thus, local flow phenomena in close proximity to the spray shield are strongly impacting on the ionization efficiency.

Luminescent Solar Concentrators with Fibre Geometry

NARCIS (Netherlands)

Edelenbosch, O.Y.; Fisher, M.; Patrignani, L.; Sark, W.G.J.H.M. van; Chatten, A.J.

2013-01-01

The potential of a fibre luminescent solar concentrator has been explored by means of both analytical and ray-tracing techniques. Coated fibres have been found to be more efficient than homogeneously doped fibres, at low absorption. For practical fibres concentration is predicted to be linear

Analytical strategy for the determination of various arsenic species in landfill leachate containing high concentrations of chlorine and organic carbon by HPLC-ICPMS

Science.gov (United States)

Bae, J.; An, J.; Kim, J.; Jung, H.; Kim, K.; Yoon, C.; Yoon, H.

2012-12-01

As a variety of wastes containing arsenic are disposed of in landfills, such facilities can play a prominent role in disseminating arsenic sources to the environment. Since it is widely recognized that arsenic toxicity is highly dependent on its species, accurate determination of various arsenic species should be considered as one of the essential goals to properly account for the potential health risk of arsenic in human and the environment. The inductively coupled plasma mass spectrometry linked to high performance liquid chromatography (HPLC-ICPMS) is acknowledged as one of the most important tools for the trace analysis of metallic speciation because of its superior separation capability and detectability. However, the complexity of matrices can cause severe interferences in the analysis results, which is the problem often encountered with HPLC-ICPMS system. High concentration of organic carbon in a sample solution causes carbon build-up on the skimmer and sampling cone, which reduces analytical sensitivity and requires a high maintenance level for its cleaning. In addition, argon from the plasma and chlorine from the sample matrix may combine to form 40Ar35Cl, which has the same nominal mass to charge (m/z) ratio as arsenic. In this respect, analytical strategy for the determination of various arsenic species (e.g., inorganic arsenite and arsenate, monomethylarsonic acid, dimethylarsinic acid, dimethyldithioarsinic acid, and arsenobetaine) in landfill leachate containing high concentrations of chlorine and organic carbon was developed in the present study. Solid phase extraction disk (i.e., C18 disk), which does not significantly adsorb any target arsenic species, was used to remove organic carbon in sample solutions. In addition, helium (He) gas was injected into the collision reaction cell equipped in ICPMS to collapse 40Ar35Cl into individual 40Ar and 35Cl. Although He gas also decreased arsenic intensity by blocking 75As, its signal to noise ratio

Variable aromatase inhibitor plasma concentrations do not correlate with circulating estrogen concentrations in post-menopausal breast cancer patients.

Science.gov (United States)

Hertz, Daniel L; Speth, Kelly A; Kidwell, Kelley M; Gersch, Christina L; Desta, Zeruesenay; Storniolo, Anna Maria; Stearns, Vered; Skaar, Todd C; Hayes, Daniel F; Henry, N Lynn; Rae, James M

2017-10-01

The aromatase inhibitors (AI) exemestane (EXE), letrozole (LET), and anastrozole suppress estrogen biosynthesis, and are effective treatments for estrogen receptor (ER)-positive breast cancer. Prior work suggests that anastrozole blood concentrations are associated with the magnitude of estrogen suppression. The objective of this study was to determine whether the magnitude of estrogen suppression, as determined by plasma estradiol (E2) concentrations, in EXE or LET treated patients is associated with plasma AI concentrations. Five hundred post-menopausal women with ER-positive breast cancer were enrolled in the prospective Exemestane and Letrozole Pharmacogenetic (ELPh) Study conducted by the COnsortium on BReast cancer phArmacogomics (COBRA) and randomly assigned to either drug. Estrogen concentrations were measured at baseline and after 3 months of AI treatment and drug concentrations were measured after 1 or 3 months. EXE or LET concentrations were compared with 3-month E2 concentration or the change from baseline to 3 months using several complementary statistical procedures. Four-hundred patients with on-treatment E2 and AI concentrations were evaluable (EXE n = 200, LET n = 200). Thirty (7.6%) patients (EXE n = 13, LET n = 17) had 3-month E2 concentrations above the lower limit of quantification (LLOQ) (median: 4.75; range: 1.42-63.8 pg/mL). EXE and LET concentrations were not associated with on-treatment E2 concentrations or changes in E2 concentrations from baseline (all p > 0.05). Steady-state plasma AI concentrations do not explain variability in E2 suppression in post-menopausal women receiving EXE or LET therapy, in contrast with prior evidence in anastrozole treated patients.

Pre-analytical and analytical variation of drug determination in segmented hair using ultra-performance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Nielsen, Marie Katrine Klose; Johansen, Sys Stybe; Linnet, Kristian

2014-01-01

Assessment of total uncertainty of analytical methods for the measurements of drugs in human hair has mainly been derived from the analytical variation. However, in hair analysis several other sources of uncertainty will contribute to the total uncertainty. Particularly, in segmental hair analysis pre-analytical variations associated with the sampling and segmentation may be significant factors in the assessment of the total uncertainty budget. The aim of this study was to develop and validate a method for the analysis of 31 common drugs in hair using ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with focus on the assessment of both the analytical and pre-analytical sampling variations. The validated method was specific, accurate (80-120%), and precise (CV≤20%) across a wide linear concentration range from 0.025-25 ng/mg for most compounds. The analytical variation was estimated to be less than 15% for almost all compounds. The method was successfully applied to 25 segmented hair specimens from deceased drug addicts showing a broad pattern of poly-drug use. The pre-analytical sampling variation was estimated from the genuine duplicate measurements of two bundles of hair collected from each subject after subtraction of the analytical component. For the most frequently detected analytes, the pre-analytical variation was estimated to be 26-69%. Thus, the pre-analytical variation was 3-7 folds larger than the analytical variation (7-13%) and hence the dominant component in the total variation (29-70%). The present study demonstrated the importance of including the pre-analytical variation in the assessment of the total uncertainty budget and in the setting of the 95%-uncertainty interval (±2CVT). Excluding the pre-analytical sampling variation could significantly affect the interpretation of results from segmental hair analysis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Effect of Omega-3 and Vitamins E + C Supplements on the Concentration of Serum B-Vitamins and Plasma Redox Aminothiol Antioxidant Status in Elderly Men after Strength Training for Three Months.

Science.gov (United States)

Stea, Tonje Holte; Stølevik, Solvor B; Berntsen, Sveinung; Ezzathkah Bastani, Nasser; Paulsen, Gøran; Lohne Seiler, Hilde; Hetlelid, Ken J; Blomhoff, Rune; Mansoor, Mohammad Azam

2016-01-01

Data on redox plasma aminothiol status in individuals on strength training are very limited. Therefore, we studied the effect of omega-3 and vitamins E + C supplementation on the concentration of B-vitamins and redox aminothiol status in elderly men after strength training for 3 months. Healthy men, age 60 ± 6 (mean ± SD) were randomly divided into 3 groups: group I received placebo (n = 17), group II consumed omega-3 (700 mg, n = 17), and group III consumed vitamins E + C (235 mg +1 g, n = 16) daily for 3 months. All participants completed a strength training program for the same period. The concentration of serum vitamin B12 decreased and the concentration of serum folate increased in group I after the intervention (p = 0.01, p = 0.009). The concentration of plasma 5-pyridoxal phosphate decreased in groups II and III (p = 0.03 and p = 0.01), whereas the concentration of serum uric acid decreased only in group II (p = 0.02). We detected an increase in the concentration of reduced form of aminothiols in all groups (p vitamins E + C supplementation affect the concentrations of serum B-vitamins and redox plasma aminothiol status in healthy elderly men on strength training. © 2016 S. Karger AG, Basel.

Core-shell nanoparticles optical sensors - Rational design of zinc ions fluorescent nanoprobes of improved analytical performance

Science.gov (United States)

Woźnica, Emilia; Gasik, Joanna; Kłucińska, Katarzyna; Kisiel, Anna; Maksymiuk, Krzysztof; Michalska, Agata

2017-10-01

In this work the effect of affinity of an analyte to a receptor on the response of nanostructural fluorimetric probes is discussed. Core-shell nanoparticles sensors are prepared that benefit from the properties of the phases involved leading to improved analytical performance. The optical transduction system chosen is independent of pH, thus the change of sample pH can be used to control the analyte - receptor affinity through the "conditional" binding constant prevailing within the lipophilic phase. It is shown that by affecting the "conditional" binding constant the performance of the sensor can be fine-tuned. As expected, increase in "conditional" affinity of the ligand embedded in the lipophilic phase to the analyte results in higher sensitivity over narrow concentration range - bulk reaction and sigmoidal shape response of emission intensity vs. logarithm of concentration changes. To induce a linear dependence of emission intensity vs. logarithm of analyte concentration covering a broad concentration range, a spatial confinement of the reaction zone is proposed, and application of core-shell nanostructures. The core material, polypyrrole nanospheres, is effectively not permeable for the analyte - ligand complex, thus the reaction is limited to the outer shell layer of the polymer prepared from poly(maleic anhydride-alt-1-octadecene). For herein introduced system a linear dependence of emission intensity vs. logarithm of Zn2+ concentration was obtained within the range from 10-7 to 10-1 M.

21 CFR 184.1979c - Whey protein concentrate.

Science.gov (United States)

2010-04-01

... the methods prescribed in section 16.057 (liquid sample), entitled “Gravimetric Method—Official Final... concentrate, on a dry product basis, based on analytical methods in the referenced sections of “Official Methods of Analysis of the Association of Official Analytical Chemists,” 13th ed. (1980), which is...

A surrogate analyte-based LC-MS/MS method for the determination of γ-hydroxybutyrate (GHB) in human urine and variation of endogenous urinary concentrations of GHB.

Science.gov (United States)

Kang, Soyoung; Oh, Seung Min; Chung, Kyu Hyuck; Lee, Sooyeun

2014-09-01

γ-Hydroxybutyrate (GHB) is a drug of abuse with a strong anesthetic effect; however, proving its ingestion through the quantification of GHB in biological specimens is not straightforward due to the endogenous presence of GHB in human blood, urine, saliva, etc. In the present study, a surrogate analyte approach was applied to accurate quantitative determination of GHB in human urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in order to overcome this issue. For this, (2)H6-GHB and (13)C2-dl-3-hydroxybutyrate were used as a surrogate standard and as an internal standard, respectively, and parallelism between the surrogate analyte approach and standard addition was investigated at the initial step. The validation results proved the method to be selective, accurate, and precise, with acceptable linearity within calibration ranges (0.1-1μg/ml). The limit of detection and the limit of quantification of (2)H6-GHB were 0.05 and 0.1μg/ml, respectively. No significant variations were observed among urine matrices from different sources. The stability of (2)H6-GHB was satisfactory under sample storage and in-process conditions. However, in vitro production of endogenous GHB was observed when the urine sample was kept under the in-process condition for 4h and under the storage conditions of 4 and -20°C. In order to facilitate the practical interpretation of urinary GHB, endogenous GHB was accurately measured in urine samples from 79 healthy volunteers using the surrogate analyte-based LC-MS/MS method developed in the present study. The unadjusted and creatinine-adjusted GHB concentrations in 74 urine samples with quantitative results ranged from 0.09 to 1.8μg/ml and from 4.5 to 530μg/mmol creatinine, respectively. No significant correlation was observed between the unadjusted and creatinine-adjusted GHB concentrations. The urinary endogenous GHB concentrations were affected by gender and age while they were not significantly influenced by habitual

[Ozone concentration distribution of urban].

Science.gov (United States)

Yin, Yong-quan; Li, Chang-mei; Ma, Gui-xia; Cui, Zhao-jie

2004-11-01

The increase of ozone concentration in urban is one of the most important research topics on environmental science. With the increase of nitrogen oxides and hydrogen-carbon compounds which are exhausted from cars, the ozone concentration in urban is obviously increased on sunlight, and threat of photochemistry smog will be possible. Therefore, it is very important to monitor and study the ozone concentration distribution in urban. The frequency-distribution, diurnal variation and monthly variation of ozone concentration were studied on the campus of Shandong University during six months monitoring. The influence of solar radiation and weather conditions on ozone concentration were discussed. The frequency of ozone concentration less than 200 microg/m3 is 96.88%. The ozone concentration has an obvious diurnal variation. The ozone concentration in the afternoon is higher than in the morning and in the evening. The maximum appears in June, when it is the strong solar radiation and high air-temperature. The weather conditions also influence the ozone concentration. The ozone concentration in clear day is higher than in rainy and cloudy day.

A comparison of tripolar concentric ring electrode and spline Laplacians on a four-layer concentric spherical model.

Science.gov (United States)

Liu, Xiang; Makeyev, Oleksandr; Besio, Walter

2011-01-01

We have simulated a four-layer concentric spherical head model. We calculated the spline and tripolar Laplacian estimates and compared them to the analytical Laplacian on the spherical surface. In the simulations we used five different dipole groups and two electrode configurations. The comparison shows that the tripolar Laplacian has higher correlation coefficient to the analytical Laplacian in the electrode configurations tested (19, standard 10/20 locations and 64 electrodes).

Analytical chemists and dinosaurs

International Nuclear Information System (INIS)

Brooks, R.R.

1987-01-01

The role of the analytical chemist in the development of the extraterrestrial impact theory for mass extinctions at the terminal Cretaceous Period is reviewed. High iridium concentrations in Cretaceous/Tertiary boundary clays have been linked to a terrestrial impact from an iridium-rich asteroid or large meteorite som 65 million years ago. Other evidence in favour of the occurrence of such an impact has been provided by the detection of shocked quartz grains originating from impact and of amorphous carbon particles similar to soot, derived presumably from wordwide wildfires at the terminal Cretaceous. Further evidence provided by the analytical chemist involves the determination of isotopic ratios such as 144 Nd/ 143 Nd, 187 Os/ 186 Os, and 87 Sr/ 86 Sr. Countervailing arguments put forward by the gradualist school (mainly palaeontological) as opposed to the catastrophists (mainly chemists and geochemists) are also presented and discussed

Analytical chemists and dinosaurs

Energy Technology Data Exchange (ETDEWEB)

Brooks, R R

1987-05-01

The role of the analytical chemist in the development of the extraterrestrial impact theory for mass extinctions at the terminal Cretaceous Period is reviewed. High iridium concentrations in Cretaceous/Tertiary boundary clays have been linked to a terrestrial impact from an iridium-rich asteroid or large meteorite som 65 million years ago. Other evidence in favour of the occurrence of such an impact has been provided by the detection of shocked quartz grains originating from impact and of amorphous carbon particles similar to soot, derived presumably from wordwide wildfires at the terminal Cretaceous. Further evidence provided by the analytical chemist involves the determination of isotopic ratios such as /sup 144/Nd//sup 143/Nd, /sup 187/Os//sup 186/Os, and /sup 87/Sr//sup 86/Sr. Countervailing arguments put forward by the gradualist school (mainly palaeontological) as opposed to the catastrophists (mainly chemists and geochemists) are also presented and discussed.

Determining passive cooling limits in CPV using an analytical thermal model

Science.gov (United States)

Gualdi, Federico; Arenas, Osvaldo; Vossier, Alexis; Dollet, Alain; Aimez, Vincent; Arès, Richard

2013-09-01

We propose an original thermal analytical model aiming to predict the practical limits of passive cooling systems for high concentration photovoltaic modules. The analytical model is described and validated by comparison with a commercial 3D finite element model. The limiting performances of flat plate cooling systems in natural convection are then derived and discussed.

Radioimmunoassay. A revolution in the analytic procedure

Energy Technology Data Exchange (ETDEWEB)

Strecker, H; Eckert, H G [Farbwerke Hoechst A.G., Frankfurt am Main (Germany, F.R.). Radiochemisches Lab.

1978-04-01

Radioimmunoassay is an analytic method which combines the sensitivity of radioactive measurement and the specificity of the antigen-antibody reaction Substances down to a concentration of some picograms per ml serum (or biological material) can be measured in the presence of a millionfold excess of otherwise interfering substances. The method is easy to carry out (test tube chemistry). The main field of application at the moment is in endocrinology; further possibilities of application are in pharmaceutical research, environmental protection, forensic medicine, and for general analytic purposes. Radioactive sources are used only in vitro in the nanocurie range, i.e. radiation exposure is negligible.

Analytical solutions for one-dimensional advection–dispersion ...

Indian Academy of Sciences (India)

We present simple analytical solutions for the unsteady advection–dispersion equations describing the pollutant concentration (, ) in one dimension. The solutions are obtained by using Laplace transformation technique. In this study we divided the river into two regions ≤ 0 and ≥0 and the origin at = 0.

Semi-analytical solutions of the Schnakenberg model of a reaction-diffusion cell with feedback

Science.gov (United States)

Al Noufaey, K. S.

2018-06-01

This paper considers the application of a semi-analytical method to the Schnakenberg model of a reaction-diffusion cell. The semi-analytical method is based on the Galerkin method which approximates the original governing partial differential equations as a system of ordinary differential equations. Steady-state curves, bifurcation diagrams and the region of parameter space in which Hopf bifurcations occur are presented for semi-analytical solutions and the numerical solution. The effect of feedback control, via altering various concentrations in the boundary reservoirs in response to concentrations in the cell centre, is examined. It is shown that increasing the magnitude of feedback leads to destabilization of the system, whereas decreasing this parameter to negative values of large magnitude stabilizes the system. The semi-analytical solutions agree well with numerical solutions of the governing equations.

Online Continuous Trace Process Analytics Using Multiplexing Gas Chromatography.

Science.gov (United States)

Wunsch, Marco R; Lehnig, Rudolf; Trapp, Oliver

2017-04-04

The analysis of impurities at a trace level in chemical products, nutrition additives, and drugs is highly important to guarantee safe products suitable for consumption. However, trace analysis in the presence of a dominating component can be a challenging task because of noncompatible linear detection ranges or strong signal overlap that suppresses the signal of interest. Here, we developed a technique for quantitative analysis using multiplexing gas chromatography (mpGC) for continuous and completely automated process trace analytics exemplified for the analysis of a CO 2 stream in a production plant for detection of benzene, toluene, ethylbenzene, and the three structural isomers of xylene (BTEX) in the concentration range of 0-10 ppb. Additional minor components are methane and methanol with concentrations up to 100 ppm. The sample is injected up to 512 times according to a pseudorandom binary sequence (PRBS) with a mean frequency of 0.1 Hz into a gas chromatograph equipped with a flame ionization detector (FID). A superimposed chromatogram is recorded which is deconvoluted into an averaged chromatogram with Hadamard transformation. Novel algorithms to maintain the data acquisition rate of the detector by application of Hadamard transformation and to suppress correlation noise induced by components with much higher concentrations than the target substances are shown. Compared to conventional GC-FID, the signal-to-noise ratio has been increased by a factor of 10 with mpGC-FID. Correspondingly, the detection limits for BTEX in CO 2 have been lowered from 10 to 1 ppb each. This has been achieved despite the presence of detectable components (methane and methanol) with a concentration about 1000 times higher than the target substances. The robustness and reliability of mpGC has been proven in a two-month field test in a chemical production plant.

A STUDY OF FISCHER 344 RATS EXPOSED TO SILICA DUST FOR SIX MONTHS AT CONCENTRATIONS OF 0, 2, 10 OR 20 MG / M3.

Energy Technology Data Exchange (ETDEWEB)

KUTZMAN,R.S.

1984-02-01

The major objective of this study was to relate the results of a series of functional tests to the compositional and structural alterations in the rat lung induced by subchronic exposure to silica dust. Fischer-344 rats were exposed for 6 hours/day, 5 days/week for 6 months to either 0, 2, 10, or 20 mg SiO{sub 2}/m{sup 3}. The general appearance of the exposed rats was not different from that of the controls. Interestingly, female rats exposed to silica dust, at all tested concentrations, gained more weight than the controls. The lung weight and the lung-to-body weight ratio was greater in the male rats exposed to the highest concentration of silica dust.

Analytical solution to the diffusion, sorption and decay chain equation in a saturated porous medium between two reservoirs

International Nuclear Information System (INIS)

Guzman, Juan; Maximov, Serguei; Escarela-Perez, Rafael; López-García, Irvin; Moranchel, Mario

2015-01-01

The diffusion and distribution coefficients are important parameters in the design of barrier systems used in radioactive repositories. These coefficients can be determined using a two-reservoir configuration, where a saturated porous medium is allocated between two reservoirs filled by stagnant water. One of the reservoirs contains a high concentration of radioisotopes. The goal of this work is to obtain an analytical solution for the concentration of all radioisotopes in the decay chain of a two-reservoir configuration. The analytical solution must be obtained by taking into account the diffusion and sorption processes. Concepts such as overvalued concentration, diffusion and decay factors are employed to this end. It is analytically proven that a factor of the solution is identical for all chains (considering a time scaling factor), if certain parameters do not change. In addition, it is proven that the concentration sensitivity, due to the distribution coefficient variation, depends of the porous medium thickness, which is practically insensitive for small porous medium thicknesses. The analytical solution for the radioisotope concentration is compared with experimental and numerical results available in literature. - Highlights: • Saturated porous media allocated between two reservoirs. • Analytical solution of the isotope transport equation. • Transport considers diffusion, sorption and decay chain

Number of core samples: Mean concentrations and confidence intervals

International Nuclear Information System (INIS)

Jensen, L.; Cromar, R.D.; Wilmarth, S.R.; Heasler, P.G.

1995-01-01

This document provides estimates of how well the mean concentration of analytes are known as a function of the number of core samples, composite samples, and replicate analyses. The estimates are based upon core composite data from nine recently sampled single-shell tanks. The results can be used when determining the number of core samples needed to ''characterize'' the waste from similar single-shell tanks. A standard way of expressing uncertainty in the estimate of a mean is with a 95% confidence interval (CI). The authors investigate how the width of a 95% CI on the mean concentration decreases as the number of observations increase. Specifically, the tables and figures show how the relative half-width (RHW) of a 95% CI decreases as the number of core samples increases. The RHW of a CI is a unit-less measure of uncertainty. The general conclusions are as follows: (1) the RHW decreases dramatically as the number of core samples is increased, the decrease is much smaller when the number of composited samples or the number of replicate analyses are increase; (2) if the mean concentration of an analyte needs to be estimated with a small RHW, then a large number of core samples is required. The estimated number of core samples given in the tables and figures were determined by specifying different sizes of the RHW. Four nominal sizes were examined: 10%, 25%, 50%, and 100% of the observed mean concentration. For a majority of analytes the number of core samples required to achieve an accuracy within 10% of the mean concentration is extremely large. In many cases, however, two or three core samples is sufficient to achieve a RHW of approximately 50 to 100%. Because many of the analytes in the data have small concentrations, this level of accuracy may be satisfactory for some applications

A reduced order model to analytically infer atmospheric CO2 concentration from stomatal and climate data

Science.gov (United States)

Konrad, Wilfried; Katul, Gabriel; Roth-Nebelsick, Anita; Grein, Michaela

2017-06-01

expression derived from water vapor gas diffusion that includes anatomical traits. When combined with isotopic measurements for long-term Ci/Ca, Ca can be analytically determined and is interpreted as the time-averaged Ca that existed over the life-span of the leaf. Key advantages of the proposed ROM are: 1) the usage of isotopic data provides constraints on the reconstructed atmospheric CO2 concentration from ν, 2) the analytical form of this approach permits direct links between parameter uncertainties and reconstructed Ca, and 3) the time-scale mismatch between the application of instantaneous leaf-gas exchange expressions constrained with longer-term isotopic data is reconciled through averaging rules and sensitivity analysis. The latter point was rarely considered in prior reconstruction studies that combined models of leaf-gas exchange and isotopic data to reconstruct Ca from ν. The proposed ROM is not without its limitations given the need to a priori assume a parameter related to the control on photosynthetic rate. The work here further explores immanent constraints for the aforementioned photosynthetic parameter.

Microchannel electrokinetics of charged analytes in buffered solutions near floating electrodes

DEFF Research Database (Denmark)

Andersen, Mathias Bækbo; Wolfcale, Trevor; Gregersen, Misha Marie

to accurately predict such behavior in these flow regimes. Experimentally, using conventional fluorescence microscopy, we investigated the concentration gradient (as well as the associated electroosmosis, induced-charge electro-osmosis, and electrophoresis) of the charged analyte near the floating electrode......We present both experimental and numerical studies of nonlinear electrokinetic flow of buffered solutions seeded with dilute analytes in a straight microchannel (0.6 μm high, 250 μm wide, and 9000 μm long) with a 0.15 μm high 60 μm wide electrode situated at the bottom center of the channel...... as a function of analyte (1 to 10 μM fluorescein and bodipy) and buffer (1 to 10 mM borate and posphate) concentrations and an externally applied voltage drop (50 to 100 V) along the channel. We have implemented a nonlinear continuum kinetics model of the system involving the electric potential, the buffer flow...

Potential sources of analytical bias and error in selected trace element data-quality analyses

Science.gov (United States)

Paul, Angela P.; Garbarino, John R.; Olsen, Lisa D.; Rosen, Michael R.; Mebane, Christopher A.; Struzeski, Tedmund M.

2016-09-28

Potential sources of analytical bias and error associated with laboratory analyses for selected trace elements where concentrations were greater in filtered samples than in paired unfiltered samples were evaluated by U.S. Geological Survey (USGS) Water Quality Specialists in collaboration with the USGS National Water Quality Laboratory (NWQL) and the Branch of Quality Systems (BQS).Causes for trace-element concentrations in filtered samples to exceed those in associated unfiltered samples have been attributed to variability in analytical measurements, analytical bias, sample contamination either in the field or laboratory, and (or) sample-matrix chemistry. These issues have not only been attributed to data generated by the USGS NWQL but have been observed in data generated by other laboratories. This study continues the evaluation of potential analytical bias and error resulting from matrix chemistry and instrument variability by evaluating the performance of seven selected trace elements in paired filtered and unfiltered surface-water and groundwater samples collected from 23 sampling sites of varying chemistries from six States, matrix spike recoveries, and standard reference materials.Filtered and unfiltered samples have been routinely analyzed on separate inductively coupled plasma-mass spectrometry instruments. Unfiltered samples are treated with hydrochloric acid (HCl) during an in-bottle digestion procedure; filtered samples are not routinely treated with HCl as part of the laboratory analytical procedure. To evaluate the influence of HCl on different sample matrices, an aliquot of the filtered samples was treated with HCl. The addition of HCl did little to differentiate the analytical results between filtered samples treated with HCl from those samples left untreated; however, there was a small, but noticeable, decrease in the number of instances where a particular trace-element concentration was greater in a filtered sample than in the associated

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.

Seasonal Variation in Human Salivary Cortisol Concentration

DEFF Research Database (Denmark)

Persson, Roger; Garde, Anne Helene; Hansen, Åse Marie

2008-01-01

Measurement of cortisol concentration can contribute important information about an individual's ability to adjust to various environmental demands of both physical and psychosocial origin. However, one uncertainty that affects the possibilities of correctly interpreting and designing field studies...... is the lack of observations of the impact of seasonal changes on cortisol excretion. For this reason, the month-to-month changes in diurnal cortisol concentration, the awakening cortisol response (ACR), maximum morning concentration, and fall during the day were studied in a group of 24 healthy men and women...... 32 to 61 yrs of age engaged in active work. On one workday for 12 consecutive months, participants collected saliva at four time points for determination of cortisol: at awakening, +30 min, +8 h, and at 21:00 h. Data were analyzed by a repeated measures design with month (12 levels) and time...

A Study of Analytical Solution for the Special Dissolution Rate Model of Rock Salt

Directory of Open Access Journals (Sweden)

Xin Yang

2017-01-01

Full Text Available By calculating the concentration distributions of rock salt solutions at the boundary layer, an ordinary differential equation for describing a special dissolution rate model of rock salt under the assumption of an instantaneous diffusion process was established to investigate the dissolution mechanism of rock salt under transient but stable conditions. The ordinary differential equation was then solved mathematically to give an analytical solution and related expressions for the dissolved radius and solution concentration. Thereafter, the analytical solution was fitted with transient dissolution test data of rock salt to provide the dissolution parameters at different flow rates, and the physical meaning of the analytical formula was also discussed. Finally, the influential factors of the analytical formula were investigated. There was approximately a linear relationship between the dissolution parameters and the flow rate. The effects of the dissolution area and initial volume of the solution on the dissolution rate equation of rock salt were computationally investigated. The results showed that the present analytical solution gives a good description of the dissolution mechanism of rock salt under some special conditions, which may provide a primary theoretical basis and an analytical way to investigate the dissolution characteristics of rock salt.

An experimental and analytical investigation of glow plug performance in ignition and flame propagation through low concentrations of H2 in a steam/fog environment

International Nuclear Information System (INIS)

Davis, B.W.

1982-01-01

Thermal igniters proposed by the Tennessee Valley Authority for intentional ignition of hydrogen in nuclear reactor containments have been tested in mixtures of air, hydrogen, and steam. The igniters, conventional diesel engine glow plugs, were tested in a 10.6 ft 3 pressure vessel with dry hydrogen concentrations from 4% to 29%, and in steam fractions of up to 50%. Dry tests indicated complete combustion consistently occurred at H 2 fractions above 8% with no combustion for concentrations below 5%. Combustion tests in the presence of steam were conducted with hydrogen volume fractions of 8%, 10%, and 12%. Steam concentrations of up to 30% consistently resulted in ignition. Most of the 40% steam fraction tests indicated a pressure rise. Circulation of the mixture improved combustion in both the dry and the steam tests, most notably at low H 2 concentrations. An analysis of the high steam fraction test data yielded evidence of the presence of small, suspended, water droplets in the combustion mixture. The suppressive influence of condensation-generated fog on combustion is evaluated. Analysis of experimental results along with results derived from analytic models have provided consistent evidence of the strong influence of mass condensation rates and fog on experimentally observed ignition and flame propagation phenomena

Analytical procedure for the titrimetric determination of uranium in concentrates

International Nuclear Information System (INIS)

Florence, T.M.; Pakalns, P.

1989-01-01

In 1964 Davis and gray published a titrimetric method for uranium which does not require column reductors, electronic instruments or inert atmospheres, and is sufficiently selective to enable uranium to be determined without prior separation. The method involves reduction of uranium (VI) to (IV) by ferrous sulphate in concentrated phosphoric acid medium. The excess ion (II) is then selectively oxidised by nitric acid using molybdenum catalyst. After addition of sulphuric acid and dilution with water, the uranium (IV) is titrated with standard potassium dichromate, using barium diphenylamine sulphonate indicator. This method has been found to be simple, precise and reliable, and applicable to a wide range of uranium-containing materials. The method given here for determining uranium in concentrates is essentially that of Davies and Gray. Its applications, apparatus, reagents, procedures and accuracy and precision are discussed. 10 refs

Laser based analytical spectroscopy of uranium

International Nuclear Information System (INIS)

Argekar, A.A.; Kulkarni, M.J.; Godbole, S.V.; Page, A.G.; Samuel, J.K.; Paranjape, D.B.; Singh Mudher, K.D.

1992-01-01

Analytical spectroscopy of uranium has been studied using a XeCl excimer laser, using the fluorescence emission of U(VI) ions doped in a solid solution of sodium fluoride (NaF) and sodium chloride (NaCl) in 3:2 proportion. An electronic circuitry involving time-gating of the photomultiplier tube and facility to integrate the analytical signal over ten laser pulses has been developed to enable laser operation and signal detection with high S/N ratio. The matrix enhanced U(VI) fluorescence emission is free from chemical and spectral interferences due to the concomitant presence of ten metallic elements generally associated with uranium. The digital signal output is highly precise and does not saturate upto 5 ppm uranium concentration. X-ray diffraction patterns obtained for uranium doped compounds at 2.5% and 10% dopant concentrations are broadly similar to that of Na 2 U 2 O 7 . The detailed studies have, however, revealed fine structure for individual peaks, thereby, revealing the formation of sodium fluoro-uranate complex which is responsible for the enhanced intensity of fluorescence emission. (author). 10 refs., 6 figs., 2 tabs

Analyte preconcentration in nanofluidic channels with nonuniform zeta potential

Science.gov (United States)

Eden, A.; McCallum, C.; Storey, B. D.; Pennathur, S.; Meinhart, C. D.

2017-12-01

It is well known that charged analytes in the presence of nonuniform electric fields concentrate at locations where the relevant driving forces balance, and a wide range of ionic stacking and focusing methods are commonly employed to leverage these physical mechanisms in order to improve signal levels in biosensing applications. In particular, nanofluidic channels with spatially varying conductivity distributions have been shown to provide increased preconcentration of charged analytes due to the existence of a finite electric double layer (EDL), in which electrostatic attraction and repulsion from charged surfaces produce nonuniform transverse ion distributions. In this work, we use numerical simulations to show that one can achieve greater levels of sample accumulation by using field-effect control via wall-embedded electrodes to tailor the surface potential heterogeneity in a nanochannel with overlapped EDLs. In addition to previously demonstrated stacking and focusing mechanisms, we find that the coupling between two-dimensional ion distributions and the axial electric field under overlapped EDL conditions can generate an ion concentration polarization interface in the middle of the channel. Under an applied electric field, this interface can be used to concentrate sample ions between two stationary regions of different surface potential and charge density. Our numerical model uses the Poisson-Nernst-Planck system of equations coupled with the Stokes equation to demonstrate the phenomenon, and we discuss in detail the driving forces behind the predicted sample enhancement. The numerical velocity and salt concentration profiles exhibit good agreement with analytical results from a simplified one-dimensional area-averaged model for several limiting cases, and we show predicted amplification ratios of up to 105.

Measurement of average radon gas concentration at workplaces

International Nuclear Information System (INIS)

Kavasi, N.; Somlai, J.; Kovacs, T.; Gorjanacz, Z.; Nemeth, Cs.; Szabo, T.; Varhegyi, A.; Hakl, J.

2003-01-01

In this paper results of measurement of average radon gas concentration at workplaces (the schools and kindergartens and the ventilated workplaces) are presented. t can be stated that the one month long measurements means very high variation (as it is obvious in the cases of the hospital cave and the uranium tailing pond). Consequently, in workplaces where the expectable changes of radon concentration considerable with the seasons should be measure for 12 months long. If it is not possible, the chosen six months period should contain summer and winter months as well. The average radon concentration during working hours can be differ considerable from the average of the whole time in the cases of frequent opening the doors and windows or using artificial ventilation. (authors)

Physical Property Modeling of Concentrated Cesium Eluate Solutions, Part I - Derivation of Models

Energy Technology Data Exchange (ETDEWEB)

Choi, A.S.; Pierce, R. A.; Edwards, T. B.; Calloway, T. B.

2005-09-15

Major analytes projected to be present in the Hanford Waste Treatment Plant cesium ion-exchange eluate solutions were identified from the available analytical data collected during radioactive bench-scale runs, and a test matrix of cesium eluate solutions was designed within the bounding concentrations of those analytes. A computer model simulating the semi-batch evaporation of cesium eluate solutions was run in conjunction with a multi-electrolyte aqueous system database to calculate the physical properties of each test matrix solution concentrated to the target endpoints of 80% and 100% saturation. The calculated physical properties were analyzed statistically and fitted into mathematical expressions for the bulk solubility, density, viscosity, heat capacity and volume reduction factor as a function of temperature and concentration of each major analyte in the eluate feed. The R{sup 2} of the resulting physical property models ranged from 0.89 to 0.99.

Problems of evaluating isotope analysis of concentrated salt solutions in potash mines

International Nuclear Information System (INIS)

Schmiedl, H.D.

1980-01-01

Three problems of quantitative evaluation of analytic D and 18 O isotope data of concentrated salt solutions are discussed: (1) Consideration of the influence of admixtures of hydrated salts in determining meteoric or marine water fractions in a concentrated salt solution, (2) analytic accuracy and detection limits in determining meteoric water in salt solutions, and (3) processes of isotopic exchange with reservoir rock and sample matrix

Nuclear and nuclear related analytical methods applied in environmental research

International Nuclear Information System (INIS)

Popescu, Ion V.; Gheboianu, Anca; Bancuta, Iulian; Cimpoca, G. V; Stihi, Claudia; Radulescu, Cristiana; Oros Calin; Frontasyeva, Marina; Petre, Marian; Dulama, Ioana; Vlaicu, G.

2010-01-01

Nuclear Analytical Methods can be used for research activities on environmental studies like water quality assessment, pesticide residues, global climatic change (transboundary), pollution and remediation. Heavy metal pollution is a problem associated with areas of intensive industrial activity. In this work the moss bio monitoring technique was employed to study the atmospheric deposition in Dambovita County Romania. Also, there were used complementary nuclear and atomic analytical methods: Neutron Activation Analysis (NAA), Atomic Absorption Spectrometry (AAS) and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). These high sensitivity analysis methods were used to determine the chemical composition of some samples of mosses placed in different areas with different pollution industrial sources. The concentrations of Cr, Fe, Mn, Ni and Zn were determined. The concentration of Fe from the same samples was determined using all these methods and we obtained a very good agreement, in statistical limits, which demonstrate the capability of these analytical methods to be applied on a large spectrum of environmental samples with the same results. (authors)

Analytical applications of oscillatory chemical reactions: determination of some pharmaceuticaly and biologically important compounds

Directory of Open Access Journals (Sweden)

Pejić Nataša D.

2012-01-01

Full Text Available Novel analytical methods for quantitive determination of analytes based on perturbations of oscillatory chemical reactions realized under open reactor conditions (continuosly fed well stirred tank reactor, CSTR, have been developed in the past twenty years. The proposed kinetic methods are generally based on the ability of the analyzed substances to change the kinetics of the chemical reactions matrix. The unambiguous correlation of quantitative characteristics of perturbations, and the amount (concentration of analyte expressed as a regression equation, or its graphics (calibration curve, enable the determination of the unknown analyte concentration. Attention is given to the development of these methods because of their simple experimental procedures, broad range of linear regression ( 10-7 10-4 mol L-1 and low limits of detection of analytes ( 10-6 10-8 mol L1, in some cases even lower than 10-12 mol L-1. Therefore, their application is very convenient for routine analysis of various inorganic and organic compounds as well as gases. This review summarizes progress made in the past 5 years on quantitative determination of pharmaceutically and biologically important compounds.

Comparative changes in monthly blood urea nitrogen, total protein ...

African Journals Online (AJOL)

The objective of this study was to determine the comparative changes in the monthly blood urea nitrogen (BUN) concentration, total protein (TP) concentration in blood serum and the body condition score of Nguni cows and heifers raised on sweetveld. Twenty-four clinically healthy animals in different parities, namely Parity ...

Analytical Chemistry Division : annual report (for) 1985

International Nuclear Information System (INIS)

Mahadevan, N.

1986-01-01

An account of the various activities of the Analytical Chemistry Division of the Bhabha Atomic Research Centre, Bombay, during 1985 is presented. The main function of the Division is to provide chemical analysis support to India's atomic energy programme. In addition, the Division also offers its analytical services, mostly for measurement of concentrations at trace levels to Indian industries and other research organization in the country. A list of these determinations is given. The report also describes the research and development (R and D) activities - both completed and in progress, in the form of individual summaries. During the year an ultra trace analytical laboratory for analysis of critical samples without contamination was set up using indigenous material and technology. Publications and training activities of the staff, training of the staff from other institution, guidance by the staff for post-graduate degree and invited talks by the staff are listed in the appendices at the end of the report. (M.G.B.)

Filter Membrane Effects on Water-Extractable Phosphorus Concentrations from Soil.

Science.gov (United States)

Norby, Jessica; Strawn, Daniel; Brooks, Erin

2018-03-01

To accurately assess P concentrations in soil extracts, standard laboratory practices for monitoring P concentrations are needed. Water-extractable P is a common analytical test to determine P availability for leaching from soils, and it is used to determine best management practices. Most P analytical tests require filtration through a filter membrane with 0.45-μm pore size to distinguish between particulate and dissolved P species. However, filter membrane type is rarely specified in method protocols, and many different types of membranes are available. In this study, three common filter membrane materials (polyether sulfone, nylon, and nitrocellulose), all with 0.45-μm pore sizes, were tested for analytical differences in total P concentrations and dissolved reactive P (DRP) concentrations in water extracts from six soils sampled from two regions. Three of the extracts from the six soil samples had different total P concentrations for all three membrane types. The other three soil extracts had significantly different total P results from at least one filter membrane type. Total P concentration differences were as great as 35%. The DRP concentrations in the extracts were dependent on filter type in five of the six soil types. Results from this research show that filter membrane type is an important parameter that affects concentrations of total P and DRP from soil extracts. Thus, membrane type should be specified in soil extraction protocols. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Determination of potassium concentration in salt water for residual beta radioactivity measurements

International Nuclear Information System (INIS)

Suarez-Navarro, J.A.; Pujol, Ll.

2004-01-01

High interferences may arise in the determination of potassium concentration in salt water. Several analytical methods were studied to determine which method provided the most accurate measurements of potassium concentration. This study is relevant for radiation protection because the exact amount of potassium in water samples must be known for determinations of residual beta activity concentration. The fitting algorithm of the calibration curve and estimation of uncertainty in potassium determinations were also studied. The reproducibility of the proposed analytical method was tested by internal and external validation. Furthermore, the residual beta activity concentration of several Spanish seawater and brackish river water samples was determined using the proposed method

Analytical fingerprint for tantalum ores from African deposits

Science.gov (United States)

Melcher, F.; Graupner, T.; Sitnikova, M.; Oberthür, T.; Henjes-Kunst, F.; Gäbler, E.; Rantitsch, G.

2009-04-01

Illegal mining of gold, diamonds, copper, cobalt and, in the last decade, "coltan" has fuelled ongoing armed conflicts and civil war in a number of African countries. Following the United Nations initiative to fingerprint the origin of conflict materials and to develop a traceability system, our working group is investigating "coltan" (i.e. columbite-tantalite) mineralization especially in Africa, also within the wider framework of establishing certified trading chains (CTC). Special attention is directed towards samples from the main Ta-Nb-Sn provinces in Africa: DR Congo, Rwanda, Mozambique, Ethiopia, Egypt and Namibia. The following factors are taken into consideration in a methodological approach capable of distinguishing the origin of tantalum ores and concentrates with the utmost probability: (1) Quality and composition of coltan concentrates vary considerably. (2) Mineralogical and chemical compositions of Ta-Nb ores are extremely complex due to the wide range of the columbite-tantalite solid solution series and its ability to incorporate many additional elements. (3) Coltan concentrates may contain a number of other tantalum-bearing minerals besides columbite-tantalite. In our approach, coltan concentrates are analyzed in a step-by-step mode. State-of-the-art analytical tools employed are automated scanning electron microscopy (Mineral Liberation Analysis; MLA), electron microprobe analysis (major and trace elements), laser ablation-ICP-MS (trace elements, isotopes), and TIMS (U-Pb dating). Mineral assemblages in the ore concentrates, major and trace element concentration patterns, and zoning characteristics in the different pegmatites from Africa distinctly differ from each other. Chondrite-normalized REE distribution patterns vary significantly between columbite, tantalite, and microlite, and also relative to major element compositions of columbites. Some locations are characterized by low REE concentrations, others are highly enriched. Samples with

Is a pre-analytical process for urinalysis required?

Science.gov (United States)

Petit, Morgane; Beaudeux, Jean-Louis; Majoux, Sandrine; Hennequin, Carole

2017-10-01

For the reliable urinary measurement of calcium, phosphate and uric acid, a pre-analytical process by adding acid or base to urine samples at laboratory is recommended in order to dissolve precipitated solutes. Several studies on different kind of samples and analysers have previously shown that a such pre-analytical treatment is useless. The objective was to study the necessity of pre-analytical treatment of urine on samples collected using the V-Monovette ® (Sarstedt) system and measured on the analyser Architect C16000 (Abbott Diagnostics). Sixty urinary samples of hospitalized patients were selected (n=30 for calcium and phosphate, and n=30 for uric acid). After acidification of urine samples for measurement of calcium and phosphate, and alkalinisation for measurement of uric acid respectively, differences between results before and after the pre-analytical treatment were compared to acceptable limits recommended by the French society of clinical biology (SFBC). No difference in concentration between before and after pre-analytical treatment of urine samples exceeded acceptable limits from SFBC for measurement of calcium and uric acid. For phosphate, only one sample exceeded these acceptable limits, showing a result paradoxically lower after acidification. In conclusion, in agreement with previous study, our results show that acidification or alkalinisation of urine samples from 24 h urines or from urination is not a pre-analytical necessity for measurement of calcium, phosphate and uric acid.

Numerical and analytical investigation of steel beam subjected to four-point bending

Science.gov (United States)

Farida, F. M.; Surahman, A.; Sofwan, A.

2018-03-01

A One type of bending tests is four-point bending test. The aim of this test is to investigate the properties and behavior of materials with structural applications. This study uses numerical and analytical studies. Results from both of these studies help to improve in experimental works. The purpose of this study is to predict steel beam behavior subjected to four-point bending test. This study intension is to analyze flexural beam subjected to four-point bending prior to experimental work. Main results of this research are location of strain gauge and LVDT on steel beam based on numerical study, manual calculation, and analytical study. Analytical study uses linear elasticity theory of solid objects. This study results is position of strain gauge and LVDT. Strain gauge is located between two concentrated loads at the top beam and bottom beam. LVDT is located between two concentrated loads.

Extending Climate Analytics-As to the Earth System Grid Federation

Science.gov (United States)

Tamkin, G.; Schnase, J. L.; Duffy, D.; McInerney, M.; Nadeau, D.; Li, J.; Strong, S.; Thompson, J. H.

2015-12-01

We are building three extensions to prior-funded work on climate analytics-as-a-service that will benefit the Earth System Grid Federation (ESGF) as it addresses the Big Data challenges of future climate research: (1) We are creating a cloud-based, high-performance Virtual Real-Time Analytics Testbed supporting a select set of climate variables from six major reanalysis data sets. This near real-time capability will enable advanced technologies like the Cloudera Impala-based Structured Query Language (SQL) query capabilities and Hadoop-based MapReduce analytics over native NetCDF files while providing a platform for community experimentation with emerging analytic technologies. (2) We are building a full-featured Reanalysis Ensemble Service comprising monthly means data from six reanalysis data sets. The service will provide a basic set of commonly used operations over the reanalysis collections. The operations will be made accessible through NASA's climate data analytics Web services and our client-side Climate Data Services (CDS) API. (3) We are establishing an Open Geospatial Consortium (OGC) WPS-compliant Web service interface to our climate data analytics service that will enable greater interoperability with next-generation ESGF capabilities. The CDS API will be extended to accommodate the new WPS Web service endpoints as well as ESGF's Web service endpoints. These activities address some of the most important technical challenges for server-side analytics and support the research community's requirements for improved interoperability and improved access to reanalysis data.

Analytical solution of the PNP equations at AC applied voltage

International Nuclear Information System (INIS)

Golovnev, Anatoly; Trimper, Steffen

2012-01-01

A symmetric binary polymer electrolyte subjected to an AC voltage is considered. The analytical solution of the Poisson–Nernst–Planck equations (PNP) is found and analyzed for small applied voltages. Three distinct time regimes offering different behavior can be discriminated. The experimentally realized stationary behavior is discussed in detail. An expression for the external current is derived. Based on the theoretical result a simple method is suggested of measuring the ion mobility and their concentration separately. -- Highlights: ► Analytical solution of Poisson–Nernst–Planck equations. ► Binary polymer electrolyte subjected to an external AC voltage. ► Three well separated time scales exhibiting different behavior. ► The experimentally realized stationary behavior is discussed in detail. ► A method is proposed measuring the mobility and the concentration separately.

Separate patient serum sodium medians from males and females provide independent information on analytical bias.

Science.gov (United States)

Hansen, Steen Ingemann; Petersen, Per Hyltoft; Lund, Flemming; Fraser, Callum G; Sölétormos, György

2017-10-26

During monitoring of monthly medians of results from patients undertaken to assess analytical stability in routine laboratory performance, the medians for serum sodium for male and female patients were found to be significantly related. Daily, weekly and monthly patient medians of serum sodium for both male and female patients were calculated from results obtained on samples from the population >18 years on three analysers in the hospital laboratory. The half-range of medians was applied as an estimate of the maximum bias. Further, the ratios between the two medians were calculated. The medians of both genders demonstrated dispersions over time, but they were closely connected in like patterns, which were confirmed by the half-range of the ratios of medians for males and females that varied from 0.36% for daily, 0.14% for weekly and 0.036% for monthly ratios over all instruments. The tight relationship between the gender medians for serum sodium is only possible when raw laboratory data are used for calculation. The two patient medians can be used to confirm both and are useful as independent estimates of analytical bias during constant calibration periods. In contrast to the gender combined median, the estimate of analytical bias can be confirmed further by calculation of the ratios of medians for males and females.

Mapping monthly rainfall erosivity in Europe

DEFF Research Database (Denmark)

Ballabio, C; Meusburger, K; Klik, A

2017-01-01

to Eastern Europe. The maps also show a clear delineation of areas with different erosivity seasonal patterns, whose spatial outline was evidenced by cluster analysis. The monthly erosivity maps can be used to develop composite indicators that map both intra-annual variability and concentration of erosive...... and seasonal R-factor maps and assess rainfall erosivity both spatially and temporally. During winter months, significant rainfall erosivity is present only in part of the Mediterranean countries. A sudden increase of erosivity occurs in major part of European Union (except Mediterranean basin, western part...... selected among various statistical models to perform the spatial interpolation due to its excellent performance, ability to model non-linearity and interpretability. The monthly prediction is an order more difficult than the annual one as it is limited by the number of covariates and, for consistency...

Analytical description of concentration dependence of surface tension in multicomponent systems

Energy Technology Data Exchange (ETDEWEB)

Dadashev, R; Kutuev, R [Complex Science Research Institute of the Science Academy of the Chechen Republic, 21 Staropromisl. shosse, Grozny 364096 (Russian Federation); Elimkhanov, D [Science Academy of the Chechen Republic (Russian Federation)], E-mail: edzhabrail@mail.ru

2008-02-15

From the basic fundamental thermodynamic expressions the equation of isotherms of the surface tension of a ternary system is received. Various assumptions concerning the concentration dependence of molar areas are usually made when the equation is derived. The dependence of the molar areas is calculated as an additive function of the structure of a volumetric phase or the structure of a surface layer. To define the concentration dependence of the molar areas we used a stricter thermodynamic expression offered by Butler. In the received equation the dependence of molar areas on the structure of the solution is taken into account. Therefore, the equation can be applied for the calculation of surface tension over a wide concentration range of the components. Unlike the known expressions, the equation includes the surface tension properties of lateral binary systems, which makes the accuracy of the calculated values considerably higher. Thus, among the advantages of the offered equation we can point out the mathematical simplicity of the received equation and the fact that the equation includes physical parameters the experimental definition of which does not present any special difficulties.

Application of quality improvement analytic methodology in emergency medicine research: A comparative evaluation.

Science.gov (United States)

Harries, Bruce; Filiatrault, Lyne; Abu-Laban, Riyad B

2018-05-30

Quality improvement (QI) analytic methodology is rarely encountered in the emergency medicine literature. We sought to comparatively apply QI design and analysis techniques to an existing data set, and discuss these techniques as an alternative to standard research methodology for evaluating a change in a process of care. We used data from a previously published randomized controlled trial on triage-nurse initiated radiography using the Ottawa ankle rules (OAR). QI analytic tools were applied to the data set from this study and evaluated comparatively against the original standard research methodology. The original study concluded that triage nurse-initiated radiographs led to a statistically significant decrease in mean emergency department length of stay. Using QI analytic methodology, we applied control charts and interpreted the results using established methods that preserved the time sequence of the data. This analysis found a compelling signal of a positive treatment effect that would have been identified after the enrolment of 58% of the original study sample, and in the 6th month of this 11-month study. Our comparative analysis demonstrates some of the potential benefits of QI analytic methodology. We found that had this approach been used in the original study, insights regarding the benefits of nurse-initiated radiography using the OAR would have been achieved earlier, and thus potentially at a lower cost. In situations where the overarching aim is to accelerate implementation of practice improvement to benefit future patients, we believe that increased consideration should be given to the use of QI analytic methodology.

Seasonal fluctuations of organophosphate concentrations in precipitation and storm water runoff.

Science.gov (United States)

Regnery, Julia; Püttmann, Wilhelm

2010-02-01

To investigate seasonal fluctuations and trends of organophosphate (flame retardants, plasticizers) concentrations in rain and snow, precipitation samples were collected in 2007-2009 period at a densely populated urban sampling site and two sparsely populated rural sampling sites in middle Germany. In addition, storm water runoff was sampled from May 2008 to April 2009 at an urban storm water holding tank (SWHT). Samples were analyzed for tris(2-chloroethyl) phosphate (TCEP), tris(2-chloro-1-methylethyl) phosphate (TCPP), tris(1,3-dichloro-2-propyl) phosphate (TDCP), tris(2-butoxyethyl) phosphate (TBEP), tri-iso-butyl phosphate (TiBP), and tri-n-butyl phosphate (TnBP) by gas chromatography-mass spectrometry after solid phase extraction. Among the six analyzed organophosphates (OPs), TCPP dominated in all precipitation and SWHT water samples with maximum concentrations exceeding 1000ngL(-1). For all analytes, no seasonal trends were observed at the urban precipitation sampling site, although atmospheric photooxidation was expected to reduce particularly concentrations of non-chlorinated OPs during transport from urban to remote areas in summer months with higher global irradiation. In the SWHT a seasonal trend with decreasing concentrations in summer/autumn is evident for the non-chlorinated OPs due to in-lake degradation but not for the chlorinated OPs. Furthermore, an accumulation of OPs deposited in SWHTs was observed with concentrations often exceeding those observed in wet precipitation. Median concentrations of TCPP (880ngL(-1)), TDCP (13ngL(-1)) and TBEP (77ngL(-1)) at the SWHT were more than twice as high as median concentrations measured at the urban precipitation sampling site (403ngL(-1), 5ngL(-1), and 21ngL(-1) respectively).

Advancing Concentrating Solar Power Research (Fact Sheet)

Energy Technology Data Exchange (ETDEWEB)

None, None

2014-02-01

Researchers at the National Renewable Energy Laboratory (NREL) provide scientific, engineering, and analytical expertise to help advance innovation in concentrating solar power (CSP). This fact sheet summarizes how NREL is advancing CSP research.

Lactate uptake against a concentration gradient

DEFF Research Database (Denmark)

Nordström, Carl-Henrik; Nielsen, Troels Halfeld; Nielsen, Hans Boye

2014-01-01

The recently published article by Jalloh et al (Jalloh I, Helmy A, Shannon RJ, Gallagher CN, Menon D, Carpenter K, Hutchinson P. Lactate uptake by the injured human brain - evidence from an arterio-venous gradient and cerebral microdialysis study. J Neurotrauma. 2013 Aug 22. [Epub ahead of print......]) concludes that lactate may be transported across the blood brain barrier into the brain against a concentration gradient. Unfortunately the authors have misinterpreted the concept of analytical imprecision and their conclusion is based on analytical artifact. As the topic of lactate transport into the brain...

Pre-analytic evaluation of volumetric absorptive microsampling and integration in a mass spectrometry-based metabolomics workflow.

Science.gov (United States)

Volani, Chiara; Caprioli, Giulia; Calderisi, Giovanni; Sigurdsson, Baldur B; Rainer, Johannes; Gentilini, Ivo; Hicks, Andrew A; Pramstaller, Peter P; Weiss, Guenter; Smarason, Sigurdur V; Paglia, Giuseppe

2017-10-01

Volumetric absorptive microsampling (VAMS) is a novel approach that allows single-drop (10 μL) blood collection. Integration of VAMS with mass spectrometry (MS)-based untargeted metabolomics is an attractive solution for both human and animal studies. However, to boost the use of VAMS in metabolomics, key pre-analytical questions need to be addressed. Therefore, in this work, we integrated VAMS in a MS-based untargeted metabolomics workflow and investigated pre-analytical strategies such as sample extraction procedures and metabolome stability at different storage conditions. We first evaluated the best extraction procedure for the polar metabolome and found that the highest number and amount of metabolites were recovered upon extraction with acetonitrile/water (70:30). In contrast, basic conditions (pH 9) resulted in divergent metabolite profiles mainly resulting from the extraction of intracellular metabolites originating from red blood cells. In addition, the prolonged storage of blood samples at room temperature caused significant changes in metabolome composition, but once the VAMS devices were stored at - 80 °C, the metabolome remained stable for up to 6 months. The time used for drying the sample did also affect the metabolome. In fact, some metabolites were rapidly degraded or accumulated in the sample during the first 48 h at room temperature, indicating that a longer drying step will significantly change the concentration in the sample. Graphical abstract Volumetric absorptive microsampling (VAMS) is a novel technology that allows single-drop blood collection and, in combination with mass spectrometry (MS)-based untargeted metabolomics, represents an attractive solution for both human and animal studies. In this work, we integrated VAMS in a MS-based untargeted metabolomics workflow and investigated pre-analytical strategies such as sample extraction procedures and metabolome stability at different storage conditions. The latter revealed that

Effect of geometry on concentration polarization in realistic heterogeneous permselective systems

Science.gov (United States)

Green, Yoav; Shloush, Shahar; Yossifon, Gilad

2014-04-01

This study extends previous analytical solutions of concentration polarization occurring solely in the depleted region, to the more realistic geometry consisting of a three-dimensional (3D) heterogeneous ion-permselective medium connecting two opposite microchambers (i.e., a three-layer system). Under the local electroneutrality approximation, the separation of variable methods is used to derive an analytical solution of the electrodiffusive problem for the two opposing asymmetric microchambers. The assumption of an ideal permselective medium allows for the analytic calculation of the 3D concentration and electric potential distributions as well as a current-voltage relation. It is shown that any asymmetry in the microchamber geometries will result in current rectification. Moreover, it is demonstrated that for non-negligible microchamber resistances, the conductance does not exhibit the expected saturation at low concentrations but instead shows a continuous decrease. The results are intended to facilitate a more direct comparison between theory and experiments, as now the voltage drop is across a realistic 3D and three-layer system.

Gaseous analytes of concern at Hanford Tank Farms. Topical report

International Nuclear Information System (INIS)

1996-01-01

Large amounts of toxic and radioactive waste materials are stored in underground tanks at DOE sites. When the vapors in the tank headspaces vent to the open atmosphere a potentially dangerous situation can occur for personnel in the area. An open-path atmospheric pollution monitor is being developed for DOE to monitor the open air space above these tanks. In developing this monitor it is important to know what hazardous gases are most likely to be found in dangerous concentrations. These gases are called the Analytes of Concern. At the present time, measurements in eight tanks have detected thirty-one analytes in at least two tanks and fifteen analytes in only one tank. In addition to these gases, Carbon tetrachloride is considered to be an Analyte of Concern because it permeates the ground around the tanks. These Analytes are described and ranked according to a Hazard Index which combines their vapor pressure, density, and approximate danger level. The top sixteen ranked analytes which have been detected in at least two tanks comprise an open-quotes Analytes of Concern Test Listclose quotes for determining the system performance of the atmospheric pollution monitor under development. A preliminary examination of the infrared spectra, barring atmospheric interferences, indicates that: The pollution monitor will detect all forty-seven Analytes exclamation point

Acid-base titrations using microfluidic paper-based analytical devices.

Science.gov (United States)

Karita, Shingo; Kaneta, Takashi

2014-12-16

Rapid and simple acid-base titration was accomplished using a novel microfluidic paper-based analytical device (μPAD). The μPAD was fabricated by wax printing and consisted of ten reservoirs for reaction and detection. The reaction reservoirs contained various amounts of a primary standard substance, potassium hydrogen phthalate (KHPth), whereas a constant amount of phenolphthalein was added to all the detection reservoirs. A sample solution containing NaOH was dropped onto the center of the μPAD and was allowed to spread to the reaction reservoirs where the KHPth neutralized it. When the amount of NaOH exceeded that of the KHPth in the reaction reservoirs, unneutralized hydroxide ion penetrated the detection reservoirs, resulting in a color reaction from the phenolphthalein. Therefore, the number of the detection reservoirs with no color change determined the concentration of the NaOH in the sample solution. The titration was completed within 1 min by visually determining the end point, which required neither instrumentation nor software. The volumes of the KHPth and phenolphthalein solutions added to the corresponding reservoirs were optimized to obtain reproducible and accurate results for the concentration of NaOH. The μPADs determined the concentration of NaOH at orders of magnitude ranging from 0.01 to 1 M. An acid sample, HCl, was also determined using Na2CO3 as a primary standard substance instead of KHPth. Furthermore, the μPAD was applicable to the titrations of nitric acid, sulfuric acid, acetic acid, and ammonia solutions. The μPADs were stable for more than 1 month when stored in darkness at room temperature, although this was reduced to only 5 days under daylight conditions. The analysis of acidic hot spring water was also demonstrated in the field using the μPAD, and the results agreed well with those obtained by classic acid-base titration.

Web Analytics

Science.gov (United States)

EPA’s Web Analytics Program collects, analyzes, and provides reports on traffic, quality assurance, and customer satisfaction metrics for EPA’s website. The program uses a variety of analytics tools, including Google Analytics and CrazyEgg.

What we-authors, reviewers and editors of scientific work-can learn from the analytical history of biological 3-nitrotyrosine.

Science.gov (United States)

Tsikas, Dimitrios

2017-07-15

Tyrosine and tyrosine residues in proteins are attacked by the reactive oxygen and nitrogen species peroxynitrite (O=N-OO - ) to generate 3-nitrotyrosine (3-NT) and 3-nitrotyrosine-proteins (3-NTProt), respectively. 3-NT and 3-NTProt are widely accepted as biomarkers of nitr(os)ative stress. Over the years many different analytical methods have been reported for 3-NT and 3-NTProt. Reported concentrations often differ by more than three orders of magnitude, indicative of serious analytical problems. Strategies to overcome pre-analytical and analytical shortcomings and pitfalls have been proposed. The present review investigated whether recently published work on the quantitative measurement of biological 3-nitrotyrosine did adequately consider the analytical past of this biomolecule. 3-Nitrotyrosine was taken as a representative of biomolecules that occur in biological samples in the pM-to-nM concentration range. This examination revealed that in many cases the main protagonists involved in the publication of scientific work, i.e., authors, reviewers and editors, failed to do so. Learning from the analytical history of 3-nitrotyrosine means advancing analytical and biological science and implies the following key issues. (1) Choosing the most reliable analytical approach in terms of sensitivity and accuracy; presently this is best feasible by stable-isotope dilution tandem mass spectrometry coupled with gas chromatography (GC-MS/MS) or liquid chromatography (LC-MS/MS). (2) Minimizing artificial formation of 3-nitrotyrosine during sample work up, a major pitfall in 3-nitrotyrosine analysis. (3) Validating adequately the final method in the intendent biological matrix and the established concentration range. (4) Inviting experts in the field for critical evaluation of the novelty and reliability of the proposed analytical method, placing special emphasis on the compliance of the analytical outcome with 3-nitrotyrosine concentrations obtained by validated GC-MS/MS and

Hanford Site background: Part 1, Soil background for nonradioactive analytes

International Nuclear Information System (INIS)

1993-04-01

The determination of soil background is one of the most important activities supporting environmental restoration and waste management on the Hanford Site. Background compositions serve as the basis for identifying soil contamination, and also as a baseline in risk assessment processes used to determine soil cleanup and treatment levels. These uses of soil background require an understanding of the extent to which analytes of concern occur naturally in the soils. This report documents the results of sampling and analysis activities designed to characterize the composition of soil background at the Hanford Site, and to evaluate the feasibility for use as Sitewide background. The compositions of naturally occurring soils in the vadose Zone have been-determined for-nonradioactive inorganic and organic analytes and related physical properties. These results confirm that a Sitewide approach to the characterization of soil background is technically sound and is a viable alternative to the determination and use of numerous local or area backgrounds that yield inconsistent definitions of contamination. Sitewide soil background consists of several types of data and is appropriate for use in identifying contamination in all soils in the vadose zone on the Hanford Site. The natural concentrations of nearly every inorganic analyte extend to levels that exceed calculated health-based cleanup limits. The levels of most inorganic analytes, however, are well below these health-based limits. The highest measured background concentrations occur in three volumetrically minor soil types, the most important of which are topsoils adjacent to the Columbia River that are rich in organic carbon. No organic analyte levels above detection were found in any of the soil samples

Characterization of the analytic performance of an electrochemical point-of-care meter for measuring β-hydroxybutyrate concentration in blood and plasma from periparturient dairy cattle.

Science.gov (United States)

Megahed, Ameer A; Hiew, Mark W H; Townsend, Jonathan R; Constable, Peter D

2017-06-01

The Precision Xtra electrochemical meter is widely used to measure blood β-hydroxybutyrate concentration (BHBb) in dairy cattle. The meter uses an algorithm optimized for human blood that assumes the HCT in cattle is the same as in people, and that intra-erythrocyte β-hydroxybutyrate (BHBe) and plasma β-hydroxybutyrate (BHBp) concentration are equivalent. The first objective was to characterize the analytic performance of the meter for measuring BHBb and BHBp in dairy cattle. The second objective was to characterize the influence of HCT and sample temperature on BHBp concentration measured by the meter. Blood and plasma samples were obtained from 106 periparturient Holstein cattle and 15 lactating Holstein cows with experimentally induced electrolyte and acid-base imbalances. Meter performance was evaluated using Deming regression and Bland-Altman plots. Multivariable linear regression was used to determine the effect of HCT and sample temperature on BHBb and BHBp concentration, respectively. The meter was linear up to BHB = 3.0 mmol/L as measured by the reference method, equivalent to meter values for BHBb > 4.5 mmol/L and BHBp > 5.2 mmol/L. An increase in HCT resulted in higher BHBb concentration. This result was partially explained by BHBe being much lower than BHBp. Changes in sample temperature caused a linear change in measured BHBp whenever BHBp > 3.0 mmol/L. Meter accuracy was markedly dependent on the BHBe-to-BHBp ratio and consequently the HCT. Therefore, the algorithm used by the meter should be revised when applied to bovine blood for improved accuracy. © 2017 American Society for Veterinary Clinical Pathology.

Blood gas sample spiking with total parenteral nutrition, lipid emulsion, and concentrated dextrose solutions as a model for predicting sample contamination based on glucose result.

Science.gov (United States)

Jara-Aguirre, Jose C; Smeets, Steven W; Wockenfus, Amy M; Karon, Brad S

2018-05-01

Evaluate the effects of blood gas sample contamination with total parenteral nutrition (TPN)/lipid emulsion and dextrose 50% (D50) solutions on blood gas and electrolyte measurement; and determine whether glucose concentration can predict blood gas sample contamination with TPN/lipid emulsion or D50. Residual lithium heparin arterial blood gas samples were spiked with TPN/lipid emulsion (0 to 15%) and D50 solutions (0 to 2.5%). Blood gas (pH, pCO2, pO2), electrolytes (Na+, K+ ionized calcium) and hemoglobin were measured with a Radiometer ABL90. Glucose concentration was measured in separated plasma by Roche Cobas c501. Chart review of neonatal blood gas results with glucose >300 mg/dL (>16.65 mmol/L) over a seven month period was performed to determine whether repeat (within 4 h) blood gas results suggested pre-analytical errors in blood gas results. Results were used to determine whether a glucose threshold could predict contamination resulting in blood gas and electrolyte results with greater than laboratory-defined allowable error. Samples spiked with 5% or more TPN/lipid emulsion solution or 1% D50 showed glucose concentration >500 mg/dL (>27.75 mmol/L) and produced blood gas (pH, pO 2 , pCO 2 ) results with greater than laboratory-defined allowable error. TPN/lipid emulsion, but not D50, produced greater than allowable error in electrolyte (Na + ,K + ,Ca ++ ,Hb) results at these concentrations. Based on chart review of 144 neonatal blood gas results with glucose >250 mg/dL received over seven months, four of ten neonatal intensive care unit (NICU) patients with glucose results >500 mg/dL and repeat blood gas results within 4 h had results highly suggestive of pre-analytical error. Only 3 of 36 NICU patients with glucose results 300-500 mg/dL and repeat blood gas results within 4 h had clear pre-analytical errors in blood gas results. Glucose concentration can be used as an indicator of significant blood sample contamination with either TPN

Role of nanoparticles in analytical solid phase microextraction (SPME)

NARCIS (Netherlands)

Zielinska, K.; Leeuwen, van H.P.

2013-01-01

Solid phase microextraction (SPME) is commonly used to measure the free concentration of fairly hydrophobic substances in aqueous media on the basis of their partitioning between sample solution and a solid phase. Here we study the role of nanoparticles that may sorb the analyte in the sample

Tritium fractionation in biological systems and in analytical procedures

International Nuclear Information System (INIS)

Kim, M.A.; Baumgaertner, F.

1991-01-01

The organically bound tritium (OBT) is evaluated in biological systems by measuring the tritium distribution ratio (R-value), i.e. tritium concentrations in organic substance to tissue water. The determination of the R-value is found to involve always isotope fractionation in applied analytical procedures and hence the evaluation of the true OBT-value in a given biological system appears more complicated than hitherto known in the literature. The present work concentrates on the tritium isotope fraction in the tissue water separation and on the resulting effects on the R-value. The analytical procedures examined are vacuum freeze drying under equilibrium and non-equilibrium conditions and azeotropic distillation. The vaporization isotope effects are determined separately in the phase transition of solid or liquid to gas in pure water systems as well as in real biological systems, e.g. maize plant. The results are systematically analysed and the influence of isotope effects on the R-value is rigorously quantified. (orig.)

Chemical clocks, oscillations, and other temporal effects in analytical chemistry: oddity or viable approach?

Science.gov (United States)

Prabhu, Gurpur Rakesh D; Witek, Henryk A; Urban, Pawel L

2018-05-31

Most analytical methods are based on "analogue" inputs from sensors of light, electric potentials, or currents. The signals obtained by such sensors are processed using certain calibration functions to determine concentrations of the target analytes. The signal readouts are normally done after an optimised and fixed time period, during which an assay mixture is incubated. This minireview covers another-and somewhat unusual-analytical strategy, which relies on the measurement of time interval between the occurrences of two distinguishable states in the assay reaction. These states manifest themselves via abrupt changes in the properties of the assay mixture (e.g. change of colour, appearance or disappearance of luminescence, change in pH, variations in optical activity or mechanical properties). In some cases, a correlation between the time of appearance/disappearance of a given property and the analyte concentration can be also observed. An example of an assay based on time measurement is an oscillating reaction, in which the period of oscillations is linked to the concentration of the target analyte. A number of chemo-chronometric assays, relying on the existing (bio)transformations or artificially designed reactions, were disclosed in the past few years. They are very attractive from the fundamental point of view but-so far-only few of them have be validated and used to address real-world problems. Then, can chemo-chronometric assays become a practical tool for chemical analysis? Is there a need for further development of such assays? We are aiming to answer these questions.

The mixed waste management facility. Monthly report, September 1995

International Nuclear Information System (INIS)

Streit, R.D.

1995-10-01

A continuing concern over the last few months was resolved with the approval of the Environmental Assessment (EA) and signing of the Finding of No Significant Impact (FONSI). This was completed in time to allow approval of the DWTF Phase 1 KD-3 and subsequent award of the construction contract for this phase (site preparation). The Project continues to make progress toward the Project Preliminary Design Review (PDR), scheduled for November 15-16, 1995. We completed the conventional feed preparation and solid feed preparation demonstration technologies (telerobotic sorting) and conducted a prereview of the Analytical Services element. Molten Salt is scheduled for October 3-4, with Water Treatment and Analytical Services completing the reviews by October 12. While a number of design issues have been raised and are being tracked, the general level of engineering progress is consistent with completing the PDR on schedule. No show-stoppers have been identified, and all items requiring resolution before PDR will be competed

The mixed waste management facility. Monthly report, September 1995

Energy Technology Data Exchange (ETDEWEB)

Streit, R.D.

1995-10-01

A continuing concern over the last few months was resolved with the approval of the Environmental Assessment (EA) and signing of the Finding of No Significant Impact (FONSI). This was completed in time to allow approval of the DWTF Phase 1 KD-3 and subsequent award of the construction contract for this phase (site preparation). The Project continues to make progress toward the Project Preliminary Design Review (PDR), scheduled for November 15-16, 1995. We completed the conventional feed preparation and solid feed preparation demonstration technologies (telerobotic sorting) and conducted a prereview of the Analytical Services element. Molten Salt is scheduled for October 3-4, with Water Treatment and Analytical Services completing the reviews by October 12. While a number of design issues have been raised and are being tracked, the general level of engineering progress is consistent with completing the PDR on schedule. No show-stoppers have been identified, and all items requiring resolution before PDR will be competed.

An analytical model for the distribution of CO2 sources and sinks, fluxes, and mean concentration within the roughness sub-layer

Science.gov (United States)

Siqueira, M. B.; Katul, G. G.

2009-12-01

A one-dimensional analytical model that predicts foliage CO2 uptake rates, turbulent fluxes, and mean concentration throughout the roughness sub-layer (RSL), a layer that extends from the ground surface up to 5 times the canopy height (h), is proposed. The model combines the mean continuity equation for CO2 with first-order closure principles for turbulent fluxes and simplified physiological and radiative transfer schemes for foliage uptake. This combination results in a second-order ordinary differential equation in which it is imposed soil respiration (RE) as lower and CO2 concentration well above the RSL as upper boundary conditions. An inverse version of the model was tested against data sets from two contrasting ecosystems: a tropical forest (TF, h=40 m) and a managed irrigated rice canopy (RC, h=0.7 m) - with good agreement noted between modeled and measured mean CO2 concentration profiles within the entire RSL (see figure). Sensitivity analysis on the model parameters revealed a plausible scaling regime between them and a dimensionless parameter defined by the ratio between external (RE) and internal (stomatal conductance) characteristics controlling the CO2 exchange process. The model can be used to infer the thickness of the RSL for CO2 exchange, the inequality in zero-plane displacement between CO2 and momentum, and its consequences on modeled CO2 fluxes. A simplified version of the solution is well suited for being incorporated into large-scale climate models. Furthermore, the model framework here can be used to a priori estimate relative contributions from the soil surface and the atmosphere to canopy-air CO2 concentration thereby making it synergetic to stable isotopes studies. Panels a) and c): Profiles of normalized measured leaf area density distribution (a) for TF and RC, respectively. Continuous lines are the constant a used in the model and dashed lines represent data-derived profiles. Panels b) and d) are modeled and ensemble-averaged measured

PAVA: Physiological and Anatomical Visual Analytics for Mapping of Tissue-Specific Concentration and Time-Course Data

Science.gov (United States)

We describe the development and implementation of a Physiological and Anatomical Visual Analytics tool (PAVA), a web browser-based application, used to visualize experimental/simulated chemical time-course data (dosimetry), epidemiological data and Physiologically-Annotated Data ...

A modeling approach to compare ΣPCB concentrations between congener-specific analyses

Science.gov (United States)

Gibson, Polly P.; Mills, Marc A.; Kraus, Johanna M.; Walters, David M.

2017-01-01

Changes in analytical methods over time pose problems for assessing long-term trends in environmental contamination by polychlorinated biphenyls (PCBs). Congener-specific analyses vary widely in the number and identity of the 209 distinct PCB chemical configurations (congeners) that are quantified, leading to inconsistencies among summed PCB concentrations (ΣPCB) reported by different studies. Here we present a modeling approach using linear regression to compare ΣPCB concentrations derived from different congener-specific analyses measuring different co-eluting groups. The approach can be used to develop a specific conversion model between any two sets of congener-specific analytical data from similar samples (similar matrix and geographic origin). We demonstrate the method by developing a conversion model for an example data set that includes data from two different analytical methods, a low resolution method quantifying 119 congeners and a high resolution method quantifying all 209 congeners. We used the model to show that the 119-congener set captured most (93%) of the total PCB concentration (i.e., Σ209PCB) in sediment and biological samples. ΣPCB concentrations estimated using the model closely matched measured values (mean relative percent difference = 9.6). General applications of the modeling approach include (a) generating comparable ΣPCB concentrations for samples that were analyzed for different congener sets; and (b) estimating the proportional contribution of different congener sets to ΣPCB. This approach may be especially valuable for enabling comparison of long-term remediation monitoring results even as analytical methods change over time. 

An Evaluation of Uncertainty Associated to Analytical Measurements of Selected Polycyclic Aromatic Compounds in Ambient Air

International Nuclear Information System (INIS)

Barrado, A. I.; Garcia, S.; Perez, R. M.

2013-01-01

This paper presents an evaluation of uncertainty associated to analytical measurement of eighteen polycyclic aromatic compounds (PACs) in ambient air by liquid chromatography with fluorescence detection (HPLC/FD). The study was focused on analyses of PM 1 0, PM 2 .5 and gas phase fractions. Main analytical uncertainty was estimated for eleven polycyclic aromatic hydrocarbons (PAHs), four nitro polycyclic aromatic hydrocarbons (nitro-PAHs) and two hydroxy polycyclic aromatic hydrocarbons (OH-PAHs) based on the analytical determination, reference material analysis and extraction step. Main contributions reached 15-30% and came from extraction process of real ambient samples, being those for nitro- PAHs the highest (20-30%). Range and mean concentration of PAC mass concentrations measured in gas phase and PM 1 0/PM 2 .5 particle fractions during a full year are also presented. Concentrations of OH-PAHs were about 2-4 orders of magnitude lower than their parent PAHs and comparable to those sparsely reported in literature. (Author)

Analytical expressions for time-resolved optically stimulated luminescence experiments in quartz

International Nuclear Information System (INIS)

Pagonis, V.; Lawless, J.; Chen, R.; Chithambo, M.L.

2011-01-01

Optically stimulated luminescence (OSL) signals can be obtained using a time-resolved optical stimulation (TR-OSL) method, also known as pulsed OSL. During TR-OSL measurements, the stimulation and emission of luminescence are experimentally separated in time using short light pulses. This paper presents analytical expressions for the TR-OSL intensity observed during and after such a pulse in quartz experiments. The analytical expressions are derived using a recently published kinetic model which describes thermal quenching phenomena in quartz samples. In addition, analytical expressions are derived for the concentration of electrons in the conduction band during and after the TR-OSL pulse, and for the maximum signals attained during optical stimulation of the samples. The relevance of the model for dosimetric applications is examined, by studying the dependence of the maximum TR-OSL signals on the degree of initial trap filling, and also on the probability of electron retrapping into the dosimetric trap. Analytical expressions are derived for two characteristic times of the TR-OSL mechanism; these times are the relaxation time for electrons in the conduction band, and the corresponding relaxation time for the radiative transition within the luminescence center. The former relaxation time is found to depend on several experimental parameters, while the latter relaxation time depends only on internal parameters characteristic of the recombination center. These differences between the two relaxation times can be explained by the presence of localized and delocalized transitions in the quartz sample. The analytical expressions in this paper are shown to be equivalent to previous analytical expressions derived using a different mathematical approach. A description of thermal quenching processes in quartz based on AlO 4 - /AlO 4 defects is presented, which illustrates the connection between the different descriptions of the luminescence process found in the literature

User-Centered Evaluation of Visual Analytics

Energy Technology Data Exchange (ETDEWEB)

Scholtz, Jean C.

2017-10-01

Visual analytics systems are becoming very popular. More domains now use interactive visualizations to analyze the ever-increasing amount and heterogeneity of data. More novel visualizations are being developed for more tasks and users. We need to ensure that these systems can be evaluated to determine that they are both useful and usable. A user-centered evaluation for visual analytics needs to be developed for these systems. While many of the typical human-computer interaction (HCI) evaluation methodologies can be applied as is, others will need modification. Additionally, new functionality in visual analytics systems needs new evaluation methodologies. There is a difference between usability evaluations and user-centered evaluations. Usability looks at the efficiency, effectiveness, and user satisfaction of users carrying out tasks with software applications. User-centered evaluation looks more specifically at the utility provided to the users by the software. This is reflected in the evaluations done and in the metrics used. In the visual analytics domain this is very challenging as users are most likely experts in a particular domain, the tasks they do are often not well defined, the software they use needs to support large amounts of different kinds of data, and often the tasks last for months. These difficulties are discussed more in the section on User-centered Evaluation. Our goal is to provide a discussion of user-centered evaluation practices for visual analytics, including existing practices that can be carried out and new methodologies and metrics that need to be developed and agreed upon by the visual analytics community. The material provided here should be of use for both researchers and practitioners in the field of visual analytics. Researchers and practitioners in HCI and interested in visual analytics will find this information useful as well as a discussion on changes that need to be made to current HCI practices to make them more suitable to

Decrease by 50% of plasma IgA tissue transglutaminase antibody concentrations within 2 months after start of gluten-free diet in children with celiac disease used as a confirming diagnostic test

DEFF Research Database (Denmark)

Lund, Flemming; Hermansen, Mette N; Pedersen, Merete F

2016-01-01

BACKGROUND: Histological examination of small bowel biopsies is normally the gold standard for the diagnosis of celiac disease (CD). The objective of this study was to investigate whether the rate of decreases in elevated plasma IgA tissue transglutaminase antibody (IgA-tTG) and/or IgG deamidated...... gliadin peptides antibody (IgG - DGP) concentrations could be used as a confirming test for CD in children on a gluten-free diet (GFD) when biopsy was omitted in the diagnostic process. METHODS: In this retrospective study we compared children (≤18 years old) with a CD-confirming biopsy (n = 16......) to children without a biopsy (n = 18). After initiation of GFD the antibody half-life (the time (T½) when the antibody concentration is 50% decreased) was determined in all children. RESULTS: Children with a biopsy (IgA-tTG, T½ = 1.9 months; IgG - DGP, T½ = 2.2 months) and children without a biopsy (Ig...

7746 CONCENTRATIONS OF FORMALDEHYDE IN RAIN WATERS ...

African Journals Online (AJOL)

Win7Ent

2013-06-03

Jun 3, 2013 ... The chromotropic acid method described by the. National Institute for ... concentration range of the formaldehyde in the rain waters varied from month to month throughout the six ... vicinity of vegetation [3]. Formaldehyde is the ...

Toxicologic evaluation of analytes from Tank 241-C-103

International Nuclear Information System (INIS)

Mahlum, D.D.; Young, J.Y.; Weller, R.E.

1994-11-01

Westinghouse Hanford Company requested PNL to assemble a toxicology review panel (TRP) to evaluate analytical data compiled by WHC, and provide advice concerning potential health effects associated with exposure to tank-vapor constituents. The team's objectives would be to (1) review procedures used for sampling vapors from tanks, (2) identify constituents in tank-vapor samples that could be related to symptoms reported by workers, (3) evaluate the toxicological implications of those constituents by comparison to establish toxicological databases, (4) provide advice for additional analytical efforts, and (5) support other activities as requested by WHC. The TRP represents a wide range of expertise, including toxicology, industrial hygiene, and occupational medicine. The TRP prepared a list of target analytes that chemists at the Oregon Graduate Institute/Sandia (OGI), Oak Ridge National Laboratory (ORNL), and PNL used to establish validated methods for quantitative analysis of head-space vapors from Tank 241-C-103. this list was used by the analytical laboratories to develop appropriate analytical methods for samples from Tank 241-C-103. Target compounds on the list included acetone, acetonitrile, ammonia, benzene, 1, 3-butadiene, butanal, n-butanol, hexane, 2-hexanone, methylene chloride, nitric oxide, nitrogen dioxide, nitrous oxide, dodecane, tridecane, propane nitrile, sulfur oxide, tributyl phosphate, and vinylidene chloride. The TRP considered constituent concentrations, current exposure limits, reliability of data relative to toxicity, consistency of the analytical data, and whether the material was carcinogenic or teratogenic. A final consideration in the analyte selection process was to include representative chemicals for each class of compounds found

Luminescent solar concentrators with fiber geometry.

Science.gov (United States)

Edelenbosch, Oreane Y; Fisher, Martyn; Patrignani, Luca; van Sark, Wilfried G J H M; Chatten, Amanda J

2013-05-06

The potential of a fibre luminescent solar concentrator has been explored by means of both analytical and ray-tracing techniques. Coated fibres have been found to be more efficient than homogeneously doped fibres, at low absorption. For practical fibres concentration is predicted to be linear with fibre length. A 1 m long, radius 1 mm, fibre LSC doped with Lumogen Red 305 is predicted to concentrate the AM1.5 g spectrum up to 1100 nm at normal incidence by ~35 x. The collection efficiency under diffuse and direct irradiance in London has been analysed showing that, even under clear sky conditions, in winter the diffuse contribution equals the direct.

Monthly oral methylprednisolone pulse treatment in progressive multiple sclerosis

DEFF Research Database (Denmark)

Ratzer, Rikke; Iversen, Pernille; Börnsen, Lars

2016-01-01

BACKGROUND: There is a large unmet need for treatments for patients with progressive multiple sclerosis (MS). Phase 2 studies with cerebrospinal fluid (CSF) biomarker outcomes may be well suited for the initial evaluation of efficacious treatments. OBJECTIVE: To evaluate the effect of monthly oral...... methylprednisolone pulse treatment on intrathecal inflammation in progressive MS. METHODS: In this open-label phase 2A study, 15 primary progressive and 15 secondary progressive MS patients received oral methylprednisolone pulse treatment for 60 weeks. Primary outcome was changes in CSF concentrations of osteopontin...... no change in the CSF concentration of osteopontin, but we observed significant improvement in clinical scores, MTR, DTI and some secondary CSF outcome measures. Adverse events were well-known side effects to methylprednisolone. CONCLUSION: Monthly methylprednisolone pulse treatment was safe, but had...

Analytical chemistry instrumentation

International Nuclear Information System (INIS)

Laing, W.R.

1986-01-01

In nine sections, 48 chapters cover 1) analytical chemistry and the environment 2) environmental radiochemistry 3) automated instrumentation 4) advances in analytical mass spectrometry 5) fourier transform spectroscopy 6) analytical chemistry of plutonium 7) nuclear analytical chemistry 8) chemometrics and 9) nuclear fuel technology

Study of the analytic quality in the determinations of Cr, Fe, Mn, Cu, Zn, Pb and Hg through conventional and nuclear analytical techniques in mosses of the MATV

International Nuclear Information System (INIS)

Caballero S, B.

2013-01-01

To evaluate the environmental risks of air pollution and to facilitate the decision-making for control, is necessary to have the capacity to generate data with analytical quality. A comparison between nuclear (Neutron activation analysis and total reflection X-ray fluorescence spectrometry) and no nuclear analytical techniques (atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry) for simultaneous determination of metal content (Cr, Cu, Fe, Hg, Mn, Pb and Zn) in mosses from Metropolitan Area of the Toluca Valley (MATV) was performed. Epiphytic mosses (Fabriona ciliaris and Leskea angustata) were sampled in two campaigns, 16 sites (urban, transition and natural) and were prepared for each technique. The biological certified reference materials were used for the quality control and to evaluate accuracy, precision, linearity, detection and quantification limits. Results show that nuclear analytical techniques and no nuclear applied in chemical analysis of Cr, Cu, Fe, Hg, Mn, Pb and Zn in moss from MATV are comparable and therefore all of these can potentially be used for this purpose. However, if its considered both, the performance parameters and economic/operational characteristics is widely recommended inductively coupled plasma optical emission spectrometry, conventional analytical technique, which showed the highest analytical grade quality. Also were observed spatial and temporal variations in the concentrations of Cr, Cu, Fe, Hg, Mn, Pb and Zn in mosses from MATV and was discussed its potential origin. The urban sites had the highest concentration of anthropogenic elements as Cr, Cu, Fe, Hg, Pb and Zn because are strongly impacted by roads with high vehicle traffic. (Author)

Analytic-metallurgical application of solid-electrolyts

International Nuclear Information System (INIS)

Sundermann, H.

1976-08-01

The measurement principle and devations are discussed. The activity and distribution coefficients are represented in multinary systems and the appropriate electrochemical-thermodynamical relationships are given of the EMF vs temperature, EMF vs concentration and EMF vs T-C plots in order to restrict the number of chemical calibrations. To define chemically the EMF-T-fields a potentio-coulometric method was established and electronic systems were developed allowing automatic recording of measured values with direct transformation into required analytical data. (orig.) [de

Analytical Control of a Starter Pig Feed Medicated with Amoxicillin

Directory of Open Access Journals (Sweden)

M. Zemanová

2008-01-01

Full Text Available Amoxicillin concentrations were determined by two independent laboratories for a pig starter feed medicated from a coated amoxicillin premix. The analytical method was previously transferred from one laboratory to the other one. The data between the two laboratories were consistent, showing ruggedness of the assay. Mean amoxicillin feed concentrations before and after pelletization were higher than 90% of the theoretical content, confirming satisfactory stability of this active ingredient in the coated form tested.

Methods of analytical check for highly pure tungsten

International Nuclear Information System (INIS)

Miklin, D.G.; Karpov, Yu.A.; Orlova, V.A.

1993-01-01

The review is devoted to the methods of high-purity tungsten analysis. Current trends in the development of this branch of analytical chemistry are considered. Application of both instrument mass-spectrometry analysis and optico-spectral, activation methods and mass-spectrometry ones with inductively-bound plasma in combination with preliminary isolation of the basis and impurity concentration is expected to be the most actual

Analytical Procedure Development to Determine Polycyclic Aromatic Compounds in the PM2.5-PM10 Fraction of Atmospheric Aerosols

International Nuclear Information System (INIS)

Barrado, A. I.; Garcia, S.; Perez, R. M.

2013-01-01

This paper presents an optimized and validated analytical methodology for the determination of various polycyclic aromatic compounds in ambient air using liquid chromatography with fluorescence detection. This analysis method was applied to samples obtained during more than one year in an area of Madrid. Selected compounds have included thirteen polycyclic hydrocarbons considered priorities by the EPA, and hydroxylated derivatives, which have been less investigated in air samples by liquid chromatography with fluorescence detection. We have characterized and compared the concentration ranges of compounds identified and studied seasonal and monthly variations. In addition, the techniques have been applied to study multivariate correlations, factor analysis and cluster analysis to extract as much information as possible for interpretation and more complete and accurate characterization of the results and their relationship with meteorological parameters and physicochemical. (Author)

Analytical cell decontamination and shielding window refurbishment. Final report, March 1984-March 1985

International Nuclear Information System (INIS)

Smokowski, R.T.

1985-01-01

This is a report on the decontamination and refurbishment of five inactive contaminated analytical cells and six zinc bromide filled shielding windows. The analytical cells became contaminated during the nuclear fuel reprocessing carried out by Nuclear Fuel Services from 1966 to 1972. The decontamination and decommissioning (D and D) work was performed in these cells to make them useful as laboratories in support of the West Valley Demonstration Project. To accomplish this objective, unnecessary equipment was removed from these cells. Necessary equipment and the interior of each cell were decontaminated and repaired. The shielding windows, essentially tanks holding zinc bromide, were drained and disassembled. The deteriorated, opaque zinc bromide was refined to optical clarity and returned to the tanks. All wastes generated in this operation were characterized and disposed of properly. All the decontamination and refurbishment was accomplished within 13 months. The Analytical Hot Cell has been turned over to Analytical Chemistry for the performance high-level waste (HLW) characterization analysis

Assessment of serum selenium levels in 2-month-old sucking calves using total reflection technique

International Nuclear Information System (INIS)

Bernardini, D.; Testoni, S.; Buoso, M.C.; Ceccato, D.; Moschini, G.; Valdes, M.; Torboli, A.

2000-01-01

The assessment of selenium status of livestock is an important aspect of production medicine as evidence for the influence of low Se levels on disease resistance in ruminants is reviewed with emphasis on susceptibility to various pathologies (such as infections, exudative diathesis, pneumonia, pancreatic degeneration). Additional evidence suggests that Se deficiency may cause muscular dystrophy in calves, while, severe deficiency has been associated with cardiomyopathy and even death. Serum Se content is a good indicator of the short term Se status and reflects the recent dietary intake of the element. Since serum Se content is a good indicator of the short term status of the element and reflects the its recent dietary intake, the present work is aimed to determine Se concentration in serum from a group of 2 months old sucking calves suspected to be severely deficient. We used the TX 2000 X-ray spectrometer manufactured by Ital Structures. The energy resolution (FWHM) of the Si(Li) detector was 137 eV for Mn Kα. Among nuclear techniques the TXRF method is the best suitable for trace element analysis in liquid or dissolved samples and can deal much easier with elemental investigation. Physical basis of used analytical method, experimental set up and the sample preparation procedure are described. The concentration data obtained are presented and discussed. (author)

Effects of Long-Term Storage Time and Original Sampling Month on Biobank Plasma Protein Concentrations

Directory of Open Access Journals (Sweden)

Stefan Enroth

2016-10-01

Full Text Available The quality of clinical biobank samples is crucial to their value for life sciences research. A number of factors related to the collection and storage of samples may affect the biomolecular composition. We have studied the effect of long-time freezer storage, chronological age at sampling, season and month of the year and on the abundance levels of 108 proteins in 380 plasma samples collected from 106 Swedish women. Storage time affected 18 proteins and explained 4.8–34.9% of the observed variance. Chronological age at sample collection after adjustment for storage-time affected 70 proteins and explained 1.1–33.5% of the variance. Seasonal variation had an effect on 15 proteins and month (number of sun hours affected 36 proteins and explained up to 4.5% of the variance after adjustment for storage-time and age. The results show that freezer storage time and collection date (month and season exerted similar effect sizes as age on the protein abundance levels. This implies that information on the sample handling history, in particular storage time, should be regarded as equally prominent covariates as age or gender and need to be included in epidemiological studies involving protein levels.

Two-dimensional analytic weighting functions for limb scattering

Science.gov (United States)

Zawada, D. J.; Bourassa, A. E.; Degenstein, D. A.

2017-10-01

Through the inversion of limb scatter measurements it is possible to obtain vertical profiles of trace species in the atmosphere. Many of these inversion methods require what is often referred to as weighting functions, or derivatives of the radiance with respect to concentrations of trace species in the atmosphere. Several radiative transfer models have implemented analytic methods to calculate weighting functions, alleviating the computational burden of traditional numerical perturbation methods. Here we describe the implementation of analytic two-dimensional weighting functions, where derivatives are calculated relative to atmospheric constituents in a two-dimensional grid of altitude and angle along the line of sight direction, in the SASKTRAN-HR radiative transfer model. Two-dimensional weighting functions are required for two-dimensional inversions of limb scatter measurements. Examples are presented where the analytic two-dimensional weighting functions are calculated with an underlying one-dimensional atmosphere. It is shown that the analytic weighting functions are more accurate than ones calculated with a single scatter approximation, and are orders of magnitude faster than a typical perturbation method. Evidence is presented that weighting functions for stratospheric aerosols calculated under a single scatter approximation may not be suitable for use in retrieval algorithms under solar backscatter conditions.

Let's Talk... Analytics

Science.gov (United States)

Oblinger, Diana G.

2012-01-01

Talk about analytics seems to be everywhere. Everyone is talking about analytics. Yet even with all the talk, many in higher education have questions about--and objections to--using analytics in colleges and universities. In this article, the author explores the use of analytics in, and all around, higher education. (Contains 1 note.)

Determination of Aluminum in Dialysis Concentrates by Atomic Absorption Spectrometry after Coprecipitation with Lanthanum Phosphate.

Science.gov (United States)

Selvi, Emine Kılıçkaya; Şahin, Uğur; Şahan, Serkan

2017-01-01

This method was developed for the determination of trace amounts of aluminum(III) in dialysis concentrates using atomic absorption spectrometry after coprecipitation with lanthanum phosphate. The analytical parameters that influenced the quantitative coprecipitation of analyte including amount of lanthanum, amount of phosfate, pH and duration time were optimized. The % recoveries of the analyte ion were in the range of 95-105 % with limit of detection (3s) of 0.5 µg l -1 . Preconcentration factor was found as 1000 and Relative Standard Deviation (RSD) % value obtained from model solutions was 2.5% for 0.02 mg L -1 . The accuracy of the method was evaluated with standard reference material (CWW-TMD Waste Water). The method was also applied to most concentrated acidic and basic dialysis concentrates with satisfactory results.

Tritium isotope fractionation in biological systems and in analytical procedures

International Nuclear Information System (INIS)

Kim, M.A.; Baumgaertner, Franz

1989-01-01

The organically bound tritium (OBT) is evaluated in biological systems by determining the tritium distribution ratio (R-value), i.e. tritium concentrations in organic substance to cell water. The determination of the R-value always involves isotope fractionation is applied analytical procedures and hence the evaluation of the true OBT -value in a given biological system appears more complicated than hitherto known in the literature. The present work concentrates on the tritium isotope fractionation in the cell water separation and on the resulting effects on the R-value. The analytical procedures examined are vacuum freeze drying under equilibrium and non-equilibrium conditions and azeotropic distillation. The vaporization isotope effects are determined separately in the phase transition of solid or liquid to gas in pure tritium water systems as well as in real biological systems, e.g. corn plant. The results are systematically analyzed and the influence of isotope effects on the R-value is rigorously quantified

Analytics for Education

Science.gov (United States)

MacNeill, Sheila; Campbell, Lorna M.; Hawksey, Martin

2014-01-01

This article presents an overview of the development and use of analytics in the context of education. Using Buckingham Shum's three levels of analytics, the authors present a critical analysis of current developments in the domain of learning analytics, and contrast the potential value of analytics research and development with real world…

The Journal of Learning Analytics: Supporting and Promoting Learning Analytics Research

OpenAIRE

Siemens, George

2014-01-01

The paper gives a brief overview of the main activities for the development of the emerging field of learning analytics led by the Society for Learning Analytics Research (SoLAR). The place of the Journal of Learning Analytics is identified Analytics is the most significant new initiative of SoLAR. 

The "Journal of Learning Analytics": Supporting and Promoting Learning Analytics Research

Science.gov (United States)

Siemens, George

2014-01-01

The paper gives a brief overview of the main activities for the development of the emerging field of learning analytics led by the Society for Learning Analytics Research (SoLAR). The place of the "Journal of Learning Analytics" is identified. Analytics is the most significant new initiative of SoLAR.

Mapping monthly rainfall erosivity in Europe.

Science.gov (United States)

Ballabio, Cristiano; Borrelli, Pasquale; Spinoni, Jonathan; Meusburger, Katrin; Michaelides, Silas; Beguería, Santiago; Klik, Andreas; Petan, Sašo; Janeček, Miloslav; Olsen, Preben; Aalto, Juha; Lakatos, Mónika; Rymszewicz, Anna; Dumitrescu, Alexandru; Tadić, Melita Perčec; Diodato, Nazzareno; Kostalova, Julia; Rousseva, Svetla; Banasik, Kazimierz; Alewell, Christine; Panagos, Panos

2017-02-01

Rainfall erosivity as a dynamic factor of soil loss by water erosion is modelled intra-annually for the first time at European scale. The development of Rainfall Erosivity Database at European Scale (REDES) and its 2015 update with the extension to monthly component allowed to develop monthly and seasonal R-factor maps and assess rainfall erosivity both spatially and temporally. During winter months, significant rainfall erosivity is present only in part of the Mediterranean countries. A sudden increase of erosivity occurs in major part of European Union (except Mediterranean basin, western part of Britain and Ireland) in May and the highest values are registered during summer months. Starting from September, R-factor has a decreasing trend. The mean rainfall erosivity in summer is almost 4 times higher (315MJmmha -1 h -1 ) compared to winter (87MJmmha -1 h -1 ). The Cubist model has been selected among various statistical models to perform the spatial interpolation due to its excellent performance, ability to model non-linearity and interpretability. The monthly prediction is an order more difficult than the annual one as it is limited by the number of covariates and, for consistency, the sum of all months has to be close to annual erosivity. The performance of the Cubist models proved to be generally high, resulting in R 2 values between 0.40 and 0.64 in cross-validation. The obtained months show an increasing trend of erosivity occurring from winter to summer starting from western to Eastern Europe. The maps also show a clear delineation of areas with different erosivity seasonal patterns, whose spatial outline was evidenced by cluster analysis. The monthly erosivity maps can be used to develop composite indicators that map both intra-annual variability and concentration of erosive events. Consequently, spatio-temporal mapping of rainfall erosivity permits to identify the months and the areas with highest risk of soil loss where conservation measures should be

Process analytical chemistry applied to actinide waste streams

International Nuclear Information System (INIS)

Day, R.S.

1994-01-01

The Department of Energy is being called upon to clean up it's legacy of waste from the nuclear complex generated during the cold war period. Los Alamos National Laboratory is actively involved in waste minimization and waste stream polishing activities associated with this clean up. The Advanced Testing Line for Actinide Separations (ATLAS) at Los Alamos serves as a developmental test bed for integrating flow sheet development of nitric acid waste streams with process analytical chemistry and process control techniques. The wastes require processing in glove boxes because of the radioactive components, thus adding to the difficulties of making analytical measurements. Process analytical chemistry methods provide real-time chemical analysis in support of existing waste stream operations and enhances the development of new waste stream polishing initiatives. The instrumentation and methods being developed on ATLAS are designed to supply near-real time analyses on virtually all of the chemical parameters found in nitric acid processing of actinide waste. These measurements supply information on important processing parameters including actinide oxidation states, free acid concentration, interfering anions and metal impurities

Corporal and testicular biometry in wild boar from birth to 12 months of age

Directory of Open Access Journals (Sweden)

Danillo Velloso Ferreira Murta

2013-02-01

Full Text Available The aim of this tudy was to evaluate corporal and testicular development in wild boars (Sus scrofa scrofa from birth to 12 months of age, evaluating body weight, biometric testicular parameters, and gonadosomatic index. Thirty-nine male wild boars from a commercial farm licensed by IBAMA were used in the study. The animals were weighed and assigned to 13 experimental groups. The testes were recovered through unilateral orchiectomy, weighed on an analytical balance and measured for length, width and thickness. Body weight and testicular measures increased with the age, up to 12 months, and were more accelerated in the first and ninth months. Initially the testicular growth pattern, between zero and nine months, followed the body growth, and the gonadosomatic index varied from 0.07 to 0.09%. Between 9 and 11 months, the testicular growth was superior to the body growth, and the gonadosomatic index varied from 0.09 to 0.16%. Finally, after 11 months of age, testicular and body growth had a similar behavior. In conclusion, body weight, testicular biometry, and gonadosomatic index development accelerated in the ninth month.

Analytical models for the 2DEG concentration and gate leakage current in AlGaN/GaN HEMTs

Science.gov (United States)

Ahmed, Nadim; Dutta, Aloke K.

2017-06-01

In this paper, we present a completely analytical model for the 2DEG concentration in AlGaN/GaN HEMTs as a function of gate bias, considering the donor-like trap states present at the metal/AlGaN interface to be the primary source of 2DEG carriers. To the best of our knowledge, this is a completely new contribution of this work. The electric field in the AlGaN layer is calculated using this model, which is further used to model the gate leakage current under reverse bias. We have modified the existing TTT (Thermionic Trap-Assisted Tunneling) current model, taking into account the effect of both metal/AlGaN interface traps as well as AlGaN bulk traps. The gate current under forward bias is also modeled using the existing thermionic emission model, approximating it by its Taylor series expansion. To take into account the effect of non-zero drain-source bias (VDS), an empirical fitting parameter is introduced in order to model the channel voltage in terms of VDS. The results of our models have been compared with the experimental data reported in the literature for three different devices, and the match is found to be excellent for both forward and reverse bias as well as for zero and non-zero VDS.

Advanced analytical techniques for boiling water reactor chemistry control

Energy Technology Data Exchange (ETDEWEB)

Alder, H P; Schenker, E [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-02-01

The analytical techniques applied can be divided into 5 classes: OFF-LINE (discontinuous, central lab), AT-LINE (discontinuous, analysis near loop), ON-LINE (continuous, analysis in bypass). In all cases pressure and temperature of the water sample are reduced. In a strict sense only IN-LINE (continuous, flow disturbance) and NON-INVASIVE (continuous, no flow disturbance) techniques are suitable for direct process control; - the ultimate goal. An overview of the analytical techniques tested in the pilot loop is given. Apart from process and overall water quality control, standard for BWR operation, the main emphasis is on water impurity characterization (crud particles, hot filtration, organic carbon); on stress corrosion crackling control for materials (corrosion potential, oxygen concentration) and on the characterization of the oxide layer on austenites (impedance spectroscopy, IR-reflection). The above mentioned examples of advanced analytical techniques have the potential of in-line or non-invasive application. They are different stages of development and are described in more detail. 28 refs, 1 fig., 5 tabs.

Design and optical performance of a nonimaging Fresnel transmissive concentrator for building integration applications

Energy Technology Data Exchange (ETDEWEB)

Chemisana, Daniel, E-mail: daniel.chemisana@macs.udl.cat [Applied Physics Section of the Polytechnic School (EPS), University of Lleida, 25001 Lleida (Spain); Ignasi Rosell, Joan [Applied Physics Section of the Polytechnic School (EPS), University of Lleida, 25001 Lleida (Spain)

2011-09-15

Highlights: {yields} The designed concentrator has an important potential for building integration. {yields} The device concentrates radiation toward a static receiver. {yields} Tracking performed by a single driver, representing an important mechanical advantage. {yields} The system reaches a global optical efficiency value of 56.38%. - Abstract: A transmissive Fresnel reflector is designed to match the needs of building integration for concentrating photovoltaic (PV), thermal (T) or hybrid photovoltaic/thermal (PVT) generation. The device concentrates radiation toward a static receiver by means of an array of reflectors which rotate collectively. All rotation axes are coplanar and parallel. A deep analytical ray tracing study has been made of the design characteristics and concentrator performance, thus determining the configuration which optimises efficiency. Numerous ray tracing numerical simulations have been performed which contrast and support the analytical results.

Design and optical performance of a nonimaging Fresnel transmissive concentrator for building integration applications

International Nuclear Information System (INIS)

Chemisana, Daniel; Ignasi Rosell, Joan

2011-01-01

Highlights: → The designed concentrator has an important potential for building integration. → The device concentrates radiation toward a static receiver. → Tracking performed by a single driver, representing an important mechanical advantage. → The system reaches a global optical efficiency value of 56.38%. - Abstract: A transmissive Fresnel reflector is designed to match the needs of building integration for concentrating photovoltaic (PV), thermal (T) or hybrid photovoltaic/thermal (PVT) generation. The device concentrates radiation toward a static receiver by means of an array of reflectors which rotate collectively. All rotation axes are coplanar and parallel. A deep analytical ray tracing study has been made of the design characteristics and concentrator performance, thus determining the configuration which optimises efficiency. Numerous ray tracing numerical simulations have been performed which contrast and support the analytical results.

Collaborative Research between Malaysian and Australian Universities on Learning Analytics: Challenges and Strategies

OpenAIRE

Z. Tasir; S. N. Kew; D. West; Z. Abdullah; D. Toohey

2016-01-01

Research on Learning Analytics is progressively developing in the higher education field by concentrating on the process of students' learning. Therefore, a research project between Malaysian and Australian Universities was initiated in 2015 to look at the use of Learning Analytics to support the development of teaching practice. The focal point of this article is to discuss and share the experiences of Malaysian and Australian universities in the process of developing the collaborative resea...

New analytical methodology to reach the actinide determination accuracy ({+-} 2%) required by the OSMOSE program

Energy Technology Data Exchange (ETDEWEB)

Boyer-Deslys, V.; Combaluzier, T.; Dalier, V.; Martin, J.C.; Viallesoubranne, C. [DRCP/SE2A/LAMM, CEA/VALRHO - Marcoule, BP 17171, 30207 Bagnols-sur-Ceze (France); Crozet, M. [LEHA, CEA/VALRHO - Marcoule, BP 17171, 30207 Bagnols-sur-Ceze (France)

2008-07-01

This article describes the analytical procedure optimized by LAMM (Laboratory for Analysis and Materials Methodology) in order to characterize the actinide-doped pellets used in the Osmose (Oscillation in Minerve of isotopes in eupraxis spectra) program (developed for transmutation reactor physics). Osmose aims at providing precise experimental data (absorption cross sections) for heavy nuclides (atomic mass from 232 to 245). This procedure requires the use of the analytical equipment and expertise of the LAMM: TIMS (Thermal Ionization Mass Spectrometer), ICP (Inductively Coupled Plasma) QMS (Quadrupole Mass Spectrometer), SFMS (Sector Field Mass Spectrometer), AES (Atomic Emission Spectrometer), alpha spectrometry and photo-gravimetric analysis. These techniques have met all the specification requirements: extended uncertainties (k=2) below {+-} 2% on the uranium and dopant concentrations, the impurity concentration and the americium-241 concentration.

Isotope correlation verification of analytical measurements for dissolver materials

International Nuclear Information System (INIS)

Satkowski, J.

1988-01-01

An independent verification of analytical results for accountability measurements of dissolver materials can be performed using the Iosotop Correlation Technique (ICT). ICT is based on the relationships that exist between the initial and final elemental concentration and isotopic abundances of the nuclear fuel. Linear correlation functions between isotopic ratios and plutonium/uranium ratios have been developed for specific reactor fuels. The application of these correlations to already existing analytical data provides a laboratory additional confidence in the reported results. Confirmation is done by a test of consistancy with historical data. ICT is being utilized with dissolver accountability measurements at the Savannah River Plant Laboratory. The application, implementation, and operating experience of this technique are presented

Comparison of tritium concentrations in rainwater, simulated infiltrating water, and groundwater

International Nuclear Information System (INIS)

Ishii, Yoshiyuki; Saito, Masaaki; Imaizumi, Hiroshi; Kato, Norio; Kitaoka, Koichi

2014-01-01

The tritium concentration in initial groundwater(i.e., freshly infiltrating rainwater) is necessary for groundwater dating. We collected simulated infiltrating water as the initial groundwater and examined its characteristics for tritium concentration. First, in Tokyo, the tritium concentration of simulated infiltrating water was compared with that of rainwater, atmospheric moisture, groundwater, spring water, and sap water. While rainwater, atmospheric moisture, and simulated infiltrating water remarkably changed month-to-month or with every rainfall event, groundwater and spring water were nearly constant throughout the year. Second, we collected the simulated infiltrating water monthly at four sampling sites widely dispersed across Japan(i.e., Sapporo, Niigata, Tokyo, and Matsuyama) from 2004 to 2010. Sapporo and Niigata showed high tritium concentrations as compared with the relatively low concentrations in Tokyo and Matsuyama. These results indicate that we can obtain annual maximum and minimum concentrations at each site, and that we can estimate the tritium concentration in initial groundwater at each site by using a mixing model composed of these maximum and minimum concentrations. (author)

Sensitivity analysis of the effect of various key parameters on fission product concentration (mass number 120 to 126)

International Nuclear Information System (INIS)

Sola, A.

1978-01-01

An analytical sensitivity analysis has been made of the effect of various parameters on the evaluation of fission product concentration. Such parameters include cross sections, decay constants, branching ratios, fission yields, flux and time. The formulae are applied to isotopes of the Tin, Antimony and Tellurium series. The agreement between analytically obtained data and that derived from a computer evaluated model is good, suggesting that the analytical representation includes all the important parameters useful to the evaluation of the fission product concentrations

Sensibility analysis of the effect of various key parameters on fission product concentration (Mass Number 133 to 138)

International Nuclear Information System (INIS)

Sola, A.

1978-01-01

An analytical sensitivity analysis has been made of the effect of various parameters on the evaluation of fission product concentration. Such parameters include cross-sections, decay constants, branching ratios, fission yields, flux and time. The formulae are applied to isotopes of the iodine, xenon, caesium and barium series. The agreement between analytically obtained data and that derived from a computer-evaluated model is good, suggesting that the analytical representation includes all the important parameters useful to the evaluation of the fission product concentrations

Determination of atmospheric concentrations of xenon radioisotopes. Progress report

International Nuclear Information System (INIS)

Abel, K.H.; Panisko, M.E.; Hensley, W.K.; Bowyer, T.W.; Perkins, R.W.

1995-07-01

Determination of radioactive xenon concentrations in the atmosphere over a two year period has been performed as part of a research program to develop real-time measurement capabilities. The initial measurements were made to develop, prove, and validate the authors technical approach, while the longer-term measurements are being undertaken to establish natural background concentrations and variability with time. The results reported were made using noble gas fraction (typically 90% Kr and 10% Xe by weight) gas samples obtained from a commercial air-reduction plant in the northeastern US over a two-year interval beginning in the fall of 1993. The concentrated gas samples were typically obtained during a 6--8 hour interval at the commercial reduction plant and were shipped overnight to their laboratory. Analysis was typically completed approximately 24 hours after sampling. The analytical separation process typically took approximately 6 hours and gamma-ray spectrometric measurements were conducted for intervals ranging from 3 to 16 hours. The technical approach involved removal of potentially interfering radon daughter radionuclides using a molecular sieve at room temperature, followed by cryogenic concentration of noble gases using a chilled (-76 C) activated carbon molecular sieve. During initial measurements both molecular sieve materials were contained in 30 foot x 1/4 inch gas chromatography columns for analytical separations. Krypton was separated from Xenon during the analytical procedure by warming the activated carbon molecular sieve to room temperature after initial noble gas concentration and actively pumping it away. Xenon-133 adsorbed to the activated charcoal molecular sieve was then quantified via its 81 keV gamma-ray using initially a p-type intrinsic germanium detector and later a higher efficiency (64% relative to a 3 inch x 3 inch sodium iodide) n-type intrinsic germanium detector

Treatment with cinacalcet increases plasma sclerostin concentration in hemodialysis patients with secondary hyperparathyroidism.

Science.gov (United States)

Kuczera, Piotr; Adamczak, Marcin; Więcek, Andrzej

2016-11-15

Sclerostin is a paracrine acting factor, which is expressed in the osteocytes and articular chondrocytes. Sclerostin decreases the osteoblast-related bone formation through the inhibition of the Wnt/β-catenin pathway. Osteocytes also express the Calcium sensing receptor which is a target for cinacalcet. The aim of this study was to assess the influence of six-month cinacalcet treatment on plasma sclerostin concentration in hemodialysed patients with secondary hyperparathyroidism (sHPT). In 58 hemodialysed patients with sHPT (PTH > 300 pg/ml) plasma sclerostin and serum PTH, calcium and phosphate concentrations were assessed before the first dose of cinacalcet and after 3 and 6 months of treatment. Serum PTH concentration decreased after 3 and 6 month of treatment from 1138 (931-1345) pg/ml to 772 (551-992) pg/ml and to 635 (430-839) pg/ml, respectively. Mean serum calcium and phosphate concentrations remained stable. Plasma sclerostin concentration increased after 3 and 6 months of treatment from 1.66 (1.35-1.96) ng/ml, to 1.77 (1.43-2.12) ng/ml and to 1.87 (1.50-2.25) ng/ml, respectively. In 42 patients with cinacalcet induced serum PTH decrease plasma sclerostin concentration increased after 3 and 6 months of treatment from 1.51 (1.19-1.84) ng/ml to 1.59 (1.29-1.89) ng/ml and to 1.75 (1.42-2.01) ng/ml, respectively. Contrary, in the 16 patients without cinacalcet induced serum PTH decrease plasma sclerostin concentration was stable. Plasma sclerostin concentrations correlated inversely with serum PTH concentrations at the baseline and also after 6 months of treatment. 1. In hemodialysed patients with secondary hyperparathyroidism treatment with cinacalcet increases plasma sclerostin concentration 2. This effect seems to be related to decrease of serum PTH concentration.

Stability of pyrimethamine in a liquid dosage formulation stored for three months.

Science.gov (United States)

Nahata, M C; Morosco, R S; Hipple, T F

1997-12-01

The stability of pyrimethamine in a liquid dosage formulation stored for up to three months was studies. Commercially available 25-mg pyrimethamine tablets were crushed with a mortar and pestle and mixed with a 1:1 mixture of Simple Syrup, NF, and 1% methylcellulose to yield a suspension with a pyrimethamine concentration of 2 mg/mL. The suspension was poured into 10 amber plastic and 10 amber glass prescription bottles; 5 plastic and 5 glass bottles were stored at 4 degrees C, and the remaining bottles were kept at 25 degrees C. Samples were collected at intervals up to 91 days and tested for pyrimethamine concentration by stability-indicating high-performance liquid chromatography. Pyrimethamine remained stable throughout the three-month study period under all conditions. At 4 degrees C, pyrimethamine concentrations remained above 96% of the initial concentration; at 25 degrees C, pyrimethamine concentrations remained above 91%. No substantial changes in pH were observed. Pyrimethamine was stable for at least 91 days in an oral suspension stored in plastic or glass prescription bottles at 4 or 25 degrees C.

Prenatal phthalate exposures and child temperament at 12 and 24 months.

Science.gov (United States)

Singer, Alison B; Wolff, Mary S; Silva, Manori J; Calafat, Antonia M; Engel, Stephanie M

2017-09-01

Gestational phthalate exposures have been adversely associated with attention, externalizing, and internalizing behaviors in childhood. Early childhood temperament may be a marker of later behavioral patterns. We therefore sought to determine whether gestational phthalate exposures were associated with infant and toddler temperament. The Mount Sinai Children's Environmental Health Study is a prospective cohort study of children born between May 1998 and July 2001 in New York City (N=404). Phthalate metabolites were measured in spot urine samples collected from pregnant women in their third trimester. Child temperament was assessed by parental report at 12-months using the Infant Behavior Questionnaire (IBQ) (N=204) and at 24-months using the Toddler Behavior Assessment Questionnaire (TBAQ) (N=279). We used multiple linear regression to evaluate associations between urinary phthalate metabolites and eleven temperament domains. Phthalate biomarker concentrations were weakly associated with lower gross motor activity levels as well as higher duration of orienting at the 12-month assessment. Mono(3-carboxypropyl) phthalate (MCPP), monobenzyl phthalate (MBzP) and the sum of metabolites of di(2-ethylhexyl) phthalate (∑DEHP) were associated with lower levels of smiling and laughing at 12 months. At 24-months, social fear and lower pleasure was linked to higher concentrations of MCPP and MBzP, and higher ∑DEHP was weakly associated with increased anger levels at 24-months. Though we observed some weak associations between biomarkers of prenatal exposure to phthalates and temperament at 12- and 24-months, overall phthalates biomarkers were not strongly associated with alterations in temperament. Copyright © 2017. Published by Elsevier B.V.

Assessment of the analytical capabilities of inductively coupled plasma-mass spectrometry

Science.gov (United States)

Taylor, Howard E.; Garbarino, John R.

1988-01-01

A thorough assessment of the analytical capabilities of inductively coupled plasma-mass spectrometry was conducted for selected analytes of importance in water quality applications and hydrologic research. A multielement calibration curve technique was designed to produce accurate and precise results in analysis times of approximately one minute. The suite of elements included Al, As, B, Ba, Be, Cd, Co, Cr, Cu, Hg, Li, Mn, Mo, Ni, Pb, Se, Sr, V, and Zn. The effects of sample matrix composition on the accuracy of the determinations showed that matrix elements (such as Na, Ca, Mg, and K) that may be present in natural water samples at concentration levels greater than 50 mg/L resulted in as much as a 10% suppression in ion current for analyte elements. Operational detection limits are presented.

Fully Automated Concentration Control of the Acidic Texturisation Process

OpenAIRE

Dannenberg, T.; Zimmer, M.; Rentsch, J.

2012-01-01

To enable a concentration control in the acidic texturing process we have closed the feedback loop from analytical data to the dosing mechanism of the used process tool. In order to analyze the process bath we used near-infrared spectroscopy in an online setup as well as ion chromatography as an inline method in a second approach. Using the developed dosing algorithm allows a concentration optimization of HF and HNO3 in dependence of the Si concentrations. This allows a further optimization o...

Analytical quality by design: a tool for regulatory flexibility and robust analytics.

Science.gov (United States)

Peraman, Ramalingam; Bhadraya, Kalva; Padmanabha Reddy, Yiragamreddy

2015-01-01

Very recently, Food and Drug Administration (FDA) has approved a few new drug applications (NDA) with regulatory flexibility for quality by design (QbD) based analytical approach. The concept of QbD applied to analytical method development is known now as AQbD (analytical quality by design). It allows the analytical method for movement within method operable design region (MODR). Unlike current methods, analytical method developed using analytical quality by design (AQbD) approach reduces the number of out-of-trend (OOT) results and out-of-specification (OOS) results due to the robustness of the method within the region. It is a current trend among pharmaceutical industry to implement analytical quality by design (AQbD) in method development process as a part of risk management, pharmaceutical development, and pharmaceutical quality system (ICH Q10). Owing to the lack explanatory reviews, this paper has been communicated to discuss different views of analytical scientists about implementation of AQbD in pharmaceutical quality system and also to correlate with product quality by design and pharmaceutical analytical technology (PAT).

Application of Statistical Methods to Activation Analytical Results near the Limit of Detection

DEFF Research Database (Denmark)

Heydorn, Kaj; Wanscher, B.

1978-01-01

Reporting actual numbers instead of upper limits for analytical results at or below the detection limit may produce reliable data when these numbers are subjected to appropriate statistical processing. Particularly in radiometric methods, such as activation analysis, where individual standard...... deviations of analytical results may be estimated, improved discrimination may be based on the Analysis of Precision. Actual experimental results from a study of the concentrations of arsenic in human skin demonstrate the power of this principle....

Analytic trigonometry

CERN Document Server

Bruce, William J; Maxwell, E A; Sneddon, I N

1963-01-01

Analytic Trigonometry details the fundamental concepts and underlying principle of analytic geometry. The title aims to address the shortcomings in the instruction of trigonometry by considering basic theories of learning and pedagogy. The text first covers the essential elements from elementary algebra, plane geometry, and analytic geometry. Next, the selection tackles the trigonometric functions of angles in general, basic identities, and solutions of equations. The text also deals with the trigonometric functions of real numbers. The fifth chapter details the inverse trigonometric functions

On-site customer analytics and reporting (OSCAR) : a portable clinical data warehouse for the in-house linking of hospital and telehealth data

NARCIS (Netherlands)

Thomaidis, P.

2014-01-01

This document conveys the results of the On-Site Customer Analytics and Reporting (OSCAR) project. This nine-month project started on January 2014 and was conducted at Philips Research in the Chronic Disease Management group as part of the H2H Analytics Project. Philips has access to telehealth data

Laser-induced Breakdown spectroscopy quantitative analysis method via adaptive analytical line selection and relevance vector machine regression model

International Nuclear Information System (INIS)

Yang, Jianhong; Yi, Cancan; Xu, Jinwu; Ma, Xianghong

2015-01-01

A new LIBS quantitative analysis method based on analytical line adaptive selection and Relevance Vector Machine (RVM) regression model is proposed. First, a scheme of adaptively selecting analytical line is put forward in order to overcome the drawback of high dependency on a priori knowledge. The candidate analytical lines are automatically selected based on the built-in characteristics of spectral lines, such as spectral intensity, wavelength and width at half height. The analytical lines which will be used as input variables of regression model are determined adaptively according to the samples for both training and testing. Second, an LIBS quantitative analysis method based on RVM is presented. The intensities of analytical lines and the elemental concentrations of certified standard samples are used to train the RVM regression model. The predicted elemental concentration analysis results will be given with a form of confidence interval of probabilistic distribution, which is helpful for evaluating the uncertainness contained in the measured spectra. Chromium concentration analysis experiments of 23 certified standard high-alloy steel samples have been carried out. The multiple correlation coefficient of the prediction was up to 98.85%, and the average relative error of the prediction was 4.01%. The experiment results showed that the proposed LIBS quantitative analysis method achieved better prediction accuracy and better modeling robustness compared with the methods based on partial least squares regression, artificial neural network and standard support vector machine. - Highlights: • Both training and testing samples are considered for analytical lines selection. • The analytical lines are auto-selected based on the built-in characteristics of spectral lines. • The new method can achieve better prediction accuracy and modeling robustness. • Model predictions are given with confidence interval of probabilistic distribution

The IAEA's programme in analytical quality control

International Nuclear Information System (INIS)

Suschny, O.

1980-10-01

The purpose of the Analytical Quality Control Programme of the International Atomic Energy Agency is to help laboratories in the Agency's Member States to assess and, if necessary, to improve the reliability of their analytical work in areas related to nuclear technology and radioisotope utilisation. This is done by the organisation of analytical intercomparisons and by the provision of certified or uncertified reference materials. Recently intercomparisons have been organised of trace element analysis in a soil and a lake sediment sample which have led to the certification of two new reference materials, SOIL-5 and SL-1 (lake sediment). A technique has been developed to recognise and to remove outlying results. Criteria have been established to classify element-concentration values into the categories ''established with a high degree of confidence'', ''established with a reasonable degree of confidence'' and ''information value only''. Four radionuclide intercomparisons have recently been carried out: W-1/1 and W-2/1 of the determination of selected radionuclides in water and Air-1/1 and Air-2/1 of that of selected radionuclides on simulated air filters. Details of the preparation of materials for these intercomparisons, and of data treatment and some results are discussed in the paper

Changes of complement values in calves during the first month of life.

Science.gov (United States)

Mueller, R; Boothby, J T; Carroll, E J; Panico, L

1983-05-01

Hemolytic complement activity and the 3rd component of complement (C3) concentrations were measured in the blood sera of 8 dams before, at, and after parturition, and in the sera of their calves before and after feeding colostrum and at fixed intervals up to 1 month of life. The mean hemolytic titer in the dams, as measured by incubating guinea pig RBC sensitized with bovine natural antibodies in serially diluted serum, was slightly less than 200 and was not influenced by parturition and onset of lactation. The titers in the sera of the calves immediately after birth ranged from 63 to 149 with a mean of 99. One day later, values in all calves had dropped markedly to a mean of 39. During the following month, the titers increased and reached the precolostral levels after about 4 weeks; however, these titers were still far below the titers measured in adult cows. A similar pattern was seen in the C3 concentration. The mean value at birth was 28% of the values measured in adult cows. Values decreased to 18% one day later and increased during the following month to 43% of the adult C3 concentration.

Analytic geometry

CERN Document Server

Burdette, A C

1971-01-01

Analytic Geometry covers several fundamental aspects of analytic geometry needed for advanced subjects, including calculus.This book is composed of 12 chapters that review the principles, concepts, and analytic proofs of geometric theorems, families of lines, the normal equation of the line, and related matters. Other chapters highlight the application of graphing, foci, directrices, eccentricity, and conic-related topics. The remaining chapters deal with the concept polar and rectangular coordinates, surfaces and curves, and planes.This book will prove useful to undergraduate trigonometric st

Educational intervention together with an on-line quality control program achieve recommended analytical goals for bedside blood glucose monitoring in a 1200-bed university hospital.

Science.gov (United States)

Sánchez-Margalet, Víctor; Rodriguez-Oliva, Manuel; Sánchez-Pozo, Cristina; Fernández-Gallardo, María Francisca; Goberna, Raimundo

2005-01-01

Portable meters for blood glucose concentrations are used at the patients bedside, as well as by patients for self-monitoring of blood glucose. Even though most devices have important technological advances that decrease operator error, the analytical goals proposed for the performance of glucose meters have been recently changed by the American Diabetes Association (ADA) to reach nurses in a 1200-bed University Hospital to achieve recommended analytical goals, so that we could improve the quality of diabetes care. We used portable glucose meters connected on-line to the laboratory after an educational program for nurses with responsibilities in point-of-care testing. We evaluated the system by assessing total error of the glucometers using high- and low-level glucose control solutions. In a period of 6 months, we collected data from 5642 control samples obtained by 14 devices (Precision PCx) directly from the control program (QC manager). The average total error for the low-level glucose control (2.77 mmol/l) was 6.3% (range 5.5-7.6%), and even lower for the high-level glucose control (16.66 mmol/l), at 4.8% (range 4.1-6.5%). In conclusion, the performance of glucose meters used in our University Hospital with more than 1000 beds not only improved after the intervention, but the meters achieved the analytical goals of the suggested ADA/National Academy of Clinical Biochemistry criteria for total error (<7.9% in the range 2.77-16.66 mmol/l glucose) and optimal total error for high glucose concentrations of <5%, which will improve the quality of care of our patients.

Simplified 2DEG carrier concentration model for composite barrier AlGaN/GaN HEMT

International Nuclear Information System (INIS)

Das, Palash; Biswas, Dhrubes

2014-01-01

The self consistent solution of Schrodinger and Poisson equations is used along with the total charge depletion model and applied with a novel approach of composite AlGaN barrier based HEMT heterostructure. The solution leaded to a completely new analytical model for Fermi energy level vs. 2DEG carrier concentration. This was eventually used to demonstrate a new analytical model for the temperature dependent 2DEG carrier concentration in AlGaN/GaN HEMT

Causality Between Urban Concentration and Environmental Quality

Directory of Open Access Journals (Sweden)

Amin Pujiati

2015-08-01

Full Text Available Population is concentrated in urban areas can cause the external diseconomies on environment if it exceeds the carrying capacity of the space and the urban economy. Otherwise the quality of the environment is getting better, led to the concentration of population in urban areas are increasingly high. This study aims to analyze the relationship of causality between the urban concentration and environmental quality in urban agglomeration areas. The data used in the study of secondary data obtained from the Central Bureau of statistics and the City Government from 2000 to 2013. The analytical method used is the Granger causality and descriptive. Granger causality study results showed no pattern of reciprocal causality, between urban concentration and the quality of the environment, but there unidirectional relationship between the urban concentration and environmental quality. This means that increasing urban concentration led to decreased environmental quality.

Evaluation method for change of concentration of nuclear fuel material

International Nuclear Information System (INIS)

Kiyono, Takeshi; Ando, Ryohei.

1997-01-01

The present invention provides a method of evaluating the change of concentration of compositions of nuclear fuel element materials loaded to a reactor along with neutron irradiation based on analytic calculation not relying on integration with time. Namely, the method of evaluating the change of concentration of nuclear fuel materials comprises evaluating the changing concentration of nuclear fuel materials based on nuclear fission, capturing of neutrons and radioactive decaying along with neutron irradiation. In this case, an optional nuclide on a nuclear conversion chain is determined as a standard nuclide. When the main fuel material is Pu-239, it is determined as the standard nuclide. The ratio of the concentration of the standard nuclide to that of the nuclide as an object of the evaluation can be expressed by the ratio of the cross sectional area of neutron nuclear reaction of the standard nuclide to the cross sectional area of the neutron nuclear reaction of the nuclide as the object of the evaluation. Accordingly, the concentration of the nuclide as the object of the evaluation can be expressed by an analysis formula shown by an analysis function for the ratio of the concentration of the standard nuclide to the cross section of the neutron nuclear reaction. As a result, by giving an optional concentration of the standard nuclide to the analysis formula, the concentration of each of other nuclides can be determined analytically. (I.S.)

Piezoresistive Cantilever Performance-Part I: Analytical Model for Sensitivity.

Science.gov (United States)

Park, Sung-Jin; Doll, Joseph C; Pruitt, Beth L

2010-02-01

An accurate analytical model for the change in resistance of a piezoresistor is necessary for the design of silicon piezoresistive transducers. Ion implantation requires a high-temperature oxidation or annealing process to activate the dopant atoms, and this treatment results in a distorted dopant profile due to diffusion. Existing analytical models do not account for the concentration dependence of piezoresistance and are not accurate for nonuniform dopant profiles. We extend previous analytical work by introducing two nondimensional factors, namely, the efficiency and geometry factors. A practical benefit of this efficiency factor is that it separates the process parameters from the design parameters; thus, designers may address requirements for cantilever geometry and fabrication process independently. To facilitate the design process, we provide a lookup table for the efficiency factor over an extensive range of process conditions. The model was validated by comparing simulation results with the experimentally determined sensitivities of piezoresistive cantilevers. We performed 9200 TSUPREM4 simulations and fabricated 50 devices from six unique process flows; we systematically explored the design space relating process parameters and cantilever sensitivity. Our treatment focuses on piezoresistive cantilevers, but the analytical sensitivity model is extensible to other piezoresistive transducers such as membrane pressure sensors.

Piezoresistive Cantilever Performance—Part I: Analytical Model for Sensitivity

Science.gov (United States)

Park, Sung-Jin; Doll, Joseph C.; Pruitt, Beth L.

2010-01-01

An accurate analytical model for the change in resistance of a piezoresistor is necessary for the design of silicon piezoresistive transducers. Ion implantation requires a high-temperature oxidation or annealing process to activate the dopant atoms, and this treatment results in a distorted dopant profile due to diffusion. Existing analytical models do not account for the concentration dependence of piezoresistance and are not accurate for nonuniform dopant profiles. We extend previous analytical work by introducing two nondimensional factors, namely, the efficiency and geometry factors. A practical benefit of this efficiency factor is that it separates the process parameters from the design parameters; thus, designers may address requirements for cantilever geometry and fabrication process independently. To facilitate the design process, we provide a lookup table for the efficiency factor over an extensive range of process conditions. The model was validated by comparing simulation results with the experimentally determined sensitivities of piezoresistive cantilevers. We performed 9200 TSUPREM4 simulations and fabricated 50 devices from six unique process flows; we systematically explored the design space relating process parameters and cantilever sensitivity. Our treatment focuses on piezoresistive cantilevers, but the analytical sensitivity model is extensible to other piezoresistive transducers such as membrane pressure sensors. PMID:20336183

Understanding Business Analytics

Science.gov (United States)

2015-01-05

analytics have been used in organizations for a variety of reasons for quite some time; ranging from the simple (generating and understanding business analytics...process. understanding business analytics 3 How well these two components are orchestrated will determine the level of success an organization has in

Review of Pre-Analytical Errors in Oral Glucose Tolerance Testing in a Tertiary Care Hospital.

Science.gov (United States)

Nanda, Rachita; Patel, Suprava; Sahoo, Sibashish; Mohapatra, Eli

2018-03-13

The pre-pre-analytical and pre-analytical phases form a major chunk of the errors in a laboratory. The process has taken into consideration a very common procedure which is the oral glucose tolerance test to identify the pre-pre-analytical errors. Quality indicators provide evidence of quality, support accountability and help in the decision making of laboratory personnel. The aim of this research is to evaluate pre-analytical performance of the oral glucose tolerance test procedure. An observational study that was conducted overa period of three months, in the phlebotomy and accessioning unit of our laboratory using questionnaire that examined the pre-pre-analytical errors through a scoring system. The pre-analytical phase was analyzed for each sample collected as per seven quality indicators. About 25% of the population gave wrong answer with regard to the question that tested the knowledge of patient preparation. The appropriateness of test result QI-1 had the most error. Although QI-5 for sample collection had a low error rate, it is a very important indicator as any wrongly collected sample can alter the test result. Evaluating the pre-analytical and pre-pre-analytical phase is essential and must be conducted routinely on a yearly basis to identify errors and take corrective action and to facilitate their gradual introduction into routine practice.

Radon concentration distribution mapping in a small detached house

International Nuclear Information System (INIS)

Muellerova, Monika; Moravcsik, Attila; Holy, Karol; Hutka, Miroslav; Hola, Olga

2013-01-01

Radon activity concentration was investigated in an older, single storey detached house. The rooms of the house are in contact with the bedrock. The house is fitted with plastic windows and populated mostly during the summer. Integral (Raduet) and continuous (AlphaGUARD) methods were used to measure the radon activity concentration. Average radon and thoron activity concentrations in the house were 150 Bq/m 3 and 40 Bq/m 3 , respectively. The impact of the house occupancy on radon activity concentration was significant only during the summer months when a decrease of radon activity concentration was recorded due to an increased ventilation rate. In the autumn and winter months, the impact of the house occupancy on radon activity concentration was relatively small - up to 20 %. The increases in radon activity concentration after the room had been thoroughly ventilated were analysed in order to estimate the ventilation rate and the rate of radon supply into the house. (orig.)

Hydrodynamic instabilities and concentration polarization coupled by osmotic pressure in a Taylor-Couette cell

Science.gov (United States)

Martinand, Denis; Tilton, Nils

2016-11-01

This study addresses analytically and numerically the coupling between hydrodynamic instabilities and osmotic pressure driven by concentration polarization. The configuration consists of a Taylor-Couette cell filled with a Newtonian fluid carrying a passive scalar. Whereas the concentric inner and outer cylinders are membranes permeable to the solvent, they totally reject the scalar. As a radial in- or outflow of solvent is imposed through both cylinders, a concentration boundary layer develops on the cylinder where the solvent exits, until an equilibrium steady state is reached. In addition, the rotation of the inner cylinder is used to drive centrifugal instabilities in the form of toroidal vortices, which interact with the concentration boundary layer. By means of the osmotic pressure, concentration polarization is found to promote or hinder the hydrodynamic instabilities, depending on capacity of the vortices and diffusion to increase the concentration field at the membrane. The results obtained by analytical stability analysis agree with dedicated Direct Numerical Simulations.

Analyticity without Differentiability

Science.gov (United States)

Kirillova, Evgenia; Spindler, Karlheinz

2008-01-01

In this article we derive all salient properties of analytic functions, including the analytic version of the inverse function theorem, using only the most elementary convergence properties of series. Not even the notion of differentiability is required to do so. Instead, analytical arguments are replaced by combinatorial arguments exhibiting…

An analytical model for solute transport through a GCL-based two-layered liner considering biodegradation

Energy Technology Data Exchange (ETDEWEB)

Guan, C. [Institute of Hydrology and Water Resources Engineering, Zhejiang University, Hangzhou 310058 (China); Xie, H.J., E-mail: xiehaijian@zju.edu.cn [Institute of Hydrology and Water Resources Engineering, Zhejiang University, Hangzhou 310058 (China); MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310058 (China); Wang, Y.Z.; Chen, Y.M.; Jiang, Y.S.; Tang, X.W. [MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310058 (China)

2014-01-01

An analytical model for solute advection and dispersion in a two-layered liner consisting of a geosynthetic clay liner (GCL) and a soil liner (SL) considering the effect of biodegradation was proposed. The analytical solution was derived by Laplace transformation and was validated over a range of parameters using the finite-layer method based software Pollute v7.0. Results show that if the half-life of the solute in GCL is larger than 1 year, the degradation in GCL can be neglected for solute transport in GCL/SL. When the half-life of GCL is less than 1 year, neglecting the effect of degradation in GCL on solute migration will result in a large difference of relative base concentration of GCL/SL (e.g., 32% for the case with half-life of 0.01 year). The 100-year solute base concentration can be reduced by a factor of 2.2 when the hydraulic conductivity of the SL was reduced by an order of magnitude. The 100-year base concentration was reduced by a factor of 155 when the half life of the contaminant in the SL was reduced by an order of magnitude. The effect of degradation is more important in approving the groundwater protection level than the hydraulic conductivity. The analytical solution can be used for experimental data fitting, verification of complicated numerical models and preliminary design of landfill liner systems. - Highlights: •Degradation of contaminants was considered in modeling solute transport in GCL/SL. •Analytical solutions were derived for assessment of GCL/SL with degradation. •Degradation in GCL can be ignored as half-life is larger than 1 year. •Base concentration is more sensitive to half-life of SL than to permeability of SL.

An analytical model for solute transport through a GCL-based two-layered liner considering biodegradation

International Nuclear Information System (INIS)

Guan, C.; Xie, H.J.; Wang, Y.Z.; Chen, Y.M.; Jiang, Y.S.; Tang, X.W.

2014-01-01

An analytical model for solute advection and dispersion in a two-layered liner consisting of a geosynthetic clay liner (GCL) and a soil liner (SL) considering the effect of biodegradation was proposed. The analytical solution was derived by Laplace transformation and was validated over a range of parameters using the finite-layer method based software Pollute v7.0. Results show that if the half-life of the solute in GCL is larger than 1 year, the degradation in GCL can be neglected for solute transport in GCL/SL. When the half-life of GCL is less than 1 year, neglecting the effect of degradation in GCL on solute migration will result in a large difference of relative base concentration of GCL/SL (e.g., 32% for the case with half-life of 0.01 year). The 100-year solute base concentration can be reduced by a factor of 2.2 when the hydraulic conductivity of the SL was reduced by an order of magnitude. The 100-year base concentration was reduced by a factor of 155 when the half life of the contaminant in the SL was reduced by an order of magnitude. The effect of degradation is more important in approving the groundwater protection level than the hydraulic conductivity. The analytical solution can be used for experimental data fitting, verification of complicated numerical models and preliminary design of landfill liner systems. - Highlights: •Degradation of contaminants was considered in modeling solute transport in GCL/SL. •Analytical solutions were derived for assessment of GCL/SL with degradation. •Degradation in GCL can be ignored as half-life is larger than 1 year. •Base concentration is more sensitive to half-life of SL than to permeability of SL

Analytical approach to the evaluation of nuclide transmutations

International Nuclear Information System (INIS)

Vukadin, Z.; Osmokrovic, P.

1995-01-01

Analytical approach to the evaluation of nuclide concentrations in a transmutation chain is presented. Non singular Bateman coefficients and depletion functions are used to overcome numerical difficulties when applying well-known Bateman solution of a simple radioactive decay. Method enables evaluation of complete decay chains without elimination of short lived radionuclides. It is efficient and accurate. Practical application of the method is demonstrated by computing the neptunium series inventory in used Candu TM fuel. (author)

Analytical evaluation of the novel Lumipulse G BRAHMS procalcitonin immunoassay.

Science.gov (United States)

Ruzzenente, Orazio; Salvagno, Gian Luca; Gelati, Matteo; Lippi, Giuseppe

2016-12-01

This study was designed to evaluate the analytical performance of the novel Lumipulse G1200 BRAHMS procalcitonin (PCT) immunoassay. This analytical evaluation encompassed the calculation of the limit of blank (LOB), limit of detection (LOD), functional sensitivity, intra- and inter-assay imprecision, confirmation of linearity and a comparison with the Vidas BRAHMS PCT assay. The LOB, LOD and functional sensitivity were 0.0010 ng/mL, 0.0016 ng/mL and 0.008 ng/mL, respectively. The total analytical imprecision was found to be 2.1% and the linearity was excellent (r=1.00) in the range of concentrations between 0.006-75.5 ng/mL. The correlation coefficient with Vidas BRAHMS PCT was 0.995 and the equation of the Passing and Bablok regression analysis was [Lumipulse G BRAHMS PCT]=0.76×[Vidas BRAHMS PCT]+0.04. The mean overall bias of Lumipulse G BRAHMS PCT versus Vidas BRAHMS PCT was -3.03 ng/mL (95% confidence interval [CI]: -4.32 to -1.74 ng/mL), whereas the mean bias in samples with PCT concentration between 0-10 ng/mL was -0.49 ng/mL (95% CI: -0.77 to -0.24 ng/mL). The diagnostic agreement was 100% at 0.5 ng/mL, 97% at 2.0 ng/mL and 95% at 10 ng/mL, respectively. These results attest that Lumipulse G BRAHMS PCT exhibits excellent analytical performance, among the best of the methods currently available on the diagnostic market. However, the significant bias compared to the Vidas BRAHMS PCT suggests that the methods cannot be used interchangeably.

SALE, Quality Control of Analytical Chemical Measurements

International Nuclear Information System (INIS)

Bush, W.J.; Gentillon, C.D.

1985-01-01

1 - Description of problem or function: The Safeguards Analytical Laboratory Evaluation (SALE) program is a statistical analysis program written to analyze the data received from laboratories participating in the SALE quality control and evaluation program. The system is aimed at identifying and reducing analytical chemical measurement errors. Samples of well-characterized materials are distributed to laboratory participants at periodic intervals for determination of uranium or plutonium concentration and isotopic distributions. The results of these determinations are statistically evaluated and participants are informed of the accuracy and precision of their results. 2 - Method of solution: Various statistical techniques produce the SALE output. Assuming an unbalanced nested design, an analysis of variance is performed, resulting in a test of significance for time and analyst effects. A trend test is performed. Both within- laboratory and between-laboratory standard deviations are calculated. 3 - Restrictions on the complexity of the problem: Up to 1500 pieces of data for each nuclear material sampled by a maximum of 75 laboratories may be analyzed

Analytical Model-Based Design Optimization of a Transverse Flux Machine

Energy Technology Data Exchange (ETDEWEB)

Hasan, Iftekhar; Husain, Tausif; Sozer, Yilmaz; Husain, Iqbal; Muljadi, Eduard

2017-02-16

This paper proposes an analytical machine design tool using magnetic equivalent circuit (MEC)-based particle swarm optimization (PSO) for a double-sided, flux-concentrating transverse flux machine (TFM). The magnetic equivalent circuit method is applied to analytically establish the relationship between the design objective and the input variables of prospective TFM designs. This is computationally less intensive and more time efficient than finite element solvers. A PSO algorithm is then used to design a machine with the highest torque density within the specified power range along with some geometric design constraints. The stator pole length, magnet length, and rotor thickness are the variables that define the optimization search space. Finite element analysis (FEA) was carried out to verify the performance of the MEC-PSO optimized machine. The proposed analytical design tool helps save computation time by at least 50% when compared to commercial FEA-based optimization programs, with results found to be in agreement with less than 5% error.

Analysis of neutronic parameters of AP1000 core for 18 month and 16/20 month cycle schemes using CASMO4E and SIMULATE-3 codes

International Nuclear Information System (INIS)

Nawaz Amjad; Yoshikawa, Hidekazu; Ming Yang

2015-01-01

AP1000 reactor is designed for 18 month of operating cycle. The core can also be used for 16/20 months of operating cycle. This study is performed to analyze and compare the neutronic parameters of typical AP1000 reactor core for 18 month and 16/20 month alternate cycle lengths. CASMO4E and SIMULATE-3 code package is used for the analysis of initial and equilibrium cores. The key reactor physics safety parameters were analyzed including power peaking factors, core radial and axial power distribution and core reactivity feedback coefficients. Moreover, the analysis of fuel depletion, fission product buildup and burnable poison behaviour with burnup is also analyzed. Full 2-D fuel assembly model in CASMO4E and full 3-D core model in SIMULATE-3 is employed to examine core performance and safety parameters. In order to evaluate the equilibrium core neutronic parameters, the equilibrium core model is attained by performing burnup analysis from initial to equilibrium cycle, where optimized transition core design is obtained so that the power peaking factors remain within designed limits. The MTC for higher concentration of critical boron concentrations is slightly positive at lower moderator temperatures. However, it remains negative at operating temperature ranges. The radial core relative power distribution indicates that low leakage capability of initial and equilibrium cores is reduced at EOC. (author)

SIMPLANT: analytic calculation of ion implantation within the Tadpance system

International Nuclear Information System (INIS)

Fawcett, R.J.

1988-04-01

An analytic method for calculating the concentration distribution of dopant atoms introduced into a multilayer semiconductor device by ion beam implantation is explained. Computer software written to apply the method is described. The operation of the software within a semiconductor process and device modelling package is outlined. Implantation distributions generated by the software are illustrated. (author)

Evaluation of analytical techniques to determine matals in Sodium

International Nuclear Information System (INIS)

Biancifiori, M.A.; Zappa, G.; Amico, A.

1985-01-01

The influence of some instrumental parameters on the analysis of CA, Co, Cr, Cu, Fe, K, Mg, Mn, and Ni in Sodium solutions, by means of Flame Atomic Absorption Spectroscopy (FAAS), is evaluated. The best operating parameters are established and the possibility of application of this analytical technique to the detection of the metallic impurities in Sodium is evaluated, considering the concentration values of nuclear interest

Progress report on the analytical determination of Ag2+

International Nuclear Information System (INIS)

Van Alsenoy, V.

1997-01-01

The strong oxidising properties of Ag 2+ have been used in the chemical and nuclear industry to destroy organic waste. We aim to apply the process on radioactive graphite, organic resins and effluents. The reaction mechanisms have been studied, taking into account the thermodynamic and kinetic properties of the different reactions involved. For the experimental analysis of these reactions, the accurate analytical determination of all species involved, including Ag 2+ , is needed. The results of a systematic study of the volumetric quantification of Ag 2+ using Tl + and BrO 3 - , and of the spectrophotometric and polarographic quantification of Ag + and Ag 2+ are described. The influence of the nitric acid during the quantification of Tl + by titration with KBrO 3 is investigated and the optimal analytical conditions for our purposes were determined. The best analytical results were obtained when the titration was carried out with maximum 3 M HNO 3 and 0.5 M NaCl. When those conditions are used, the determination is accurate and reproducible. The prepared Ag 2+ solutions were analysed for Ag + using polarography with a platinum electrode. The benefits and the limitation of the polarographic measurement of Ag + using a platinum electrode are described. An indirect measurement was performed by the determination of Ce 4+ after reaction with Ce 3+ . The produced Ce 4+ was measured by direct spectrophotometry. In the future, the quantification of Ag 2+ by measuring the Ce 4+ concentration produced by the reaction with Ce 3+ , will also be verified using potentiometric titration with Fe 2+ . Ag 2+ can also be determined by the direct spectrophotometry. There is a region in which the absorbance of Ag 2+ changes linearly with the concentration. Further evaluation of the titrimetric, spectrophotometric and polarographic methods will continue, until two methods give comparable Ag 2+ concentrations, beginning with the potentiometric titration of Ce 4+ with Fe 2+

Maternal Obesity, 25-Hydroxy Vitamin D Concentration, and Bone Density in Breastfeeding Dyads.

Science.gov (United States)

Sen, Sarbattama; Penfield-Cyr, Annie; Hollis, Bruce W; Wagner, Carol L

2017-08-01

To examine the association between maternal body mass index (BMI) and serum 25-hydroxy vitamin D [25(OH)D] concentration and bone density in mother-infant pairs. The study was a secondary analysis of 234 exclusively breastfeeding dyads who were recruited in the first postpartum month for a randomized controlled trial of maternal vs infant vitamin D supplementation. Mean 25(OH)D concentrations and bone mineral density (BMD) were compared by BMI group. The adjusted association between maternal BMI and 25(OH)D and bone density was examined at 1, 4, and 7 months postpartum. Obese breastfeeding women had lower 25(OH)D concentrations and higher BMD than lean women at all 3 time points (P  maternal BMI was associated with lower maternal serum levels of 25(OH)D at 1, 4, and 7 months postpartum (adjusted β = -0.45 ng/ml per kg/m 2 , 95% CI -.076, -0.14, at 1 month) and higher BMD at the same time points (β = 0.006 BMD z score; 95% CI 0.003, 0.01 at 1 month). Seventy-six percent of infants were vitamin D deficient at 1 month of age. Infants born to overweight and obese mothers had lower 25(OH)D concentrations than infants of lean mothers (P maternal supplementation group, higher maternal BMI was associated with lower 25(OH)D concentrations at 4 months (β = -0.68; 95% CI -1.17, -0.20) and lower bone density at 7 months (β = -0.001; 95% CI -0.002, -0.0001). In exclusively breastfeeding dyads, maternal obesity is associated with lower maternal and infant serum 25(OH)D concentrations, which may impact infant bone density. ClinicalTrials.gov: NCT00412074. Copyright © 2017 Elsevier Inc. All rights reserved.

Suggested benchmarks for shape optimization for minimum stress concentration

DEFF Research Database (Denmark)

Pedersen, Pauli

2008-01-01

Shape optimization for minimum stress concentration is vital, important, and difficult. New formulations and numerical procedures imply the need for good benchmarks. The available analytical shape solutions rely on assumptions that are seldom satisfied, so here, we suggest alternative benchmarks...

Quantification of analytes affected by relevant interfering signals under quality controlled conditions

International Nuclear Information System (INIS)

Bettencourt da Silva, Ricardo J.N.; Santos, Julia R.; Camoes, M. Filomena G.F.C.

2006-01-01

The analysis of organic contaminants or residues in biological samples is frequently affected by the presence of compounds producing interfering instrumental signals. This feature is responsible for the higher complexity and cost of these analyses and/or by a significant reduction of the number of studied analytes in a multi-analyte method. This work presents a methodology to estimate the impact of the interfering compounds on the quality of the analysis of complex samples, based on separative instrumental methods of analysis, aiming at supporting the inclusion of analytes affected by interfering compounds in the list of compounds analysed in the studied samples. The proposed methodology involves the study of the magnitude of the signal produced by the interfering compounds in the analysed matrix, and is applicable to analytical systems affected by interfering compounds with varying concentration in the studied matrix. The proposed methodology is based on the comparison of the signals from a representative number of examples of the studied matrix, in order to estimate the impact of the presence of such compounds on the measurement quality. The treatment of the chromatographic signals necessary to collect these data can be easily performed considering algorithms of subtraction of chromatographic signals available in most of the analytical instrumentation software. The subtraction of the interfering compounds signal from the sample signal allows the compensation of the interfering effect irrespective of the relative magnitude of the interfering and analyte signals, supporting the applicability of the same model of the method performance for a broader concentration range. The quantification of the measurement uncertainty was performed using the differential approach, which allows the estimation of the contribution of the presence of the interfering compounds to the quality of the measurement. The proposed methodology was successfully applied to the analysis of

Advanced techniques for analytic liquid wastes management in the Rokkasho reprocessing plant

International Nuclear Information System (INIS)

Madic, C.; Moulin, J.P.; Runge, S.; Schott, R.; Kashiwai, T.; Hayashi, M.

1991-01-01

The JNFS Rokkasho reprocessing plant is a large scale commercial reprocessing plant. Liquid waste treatment relies on concentration by evaporation. The management of liquid wastes is rather sophisticated and implies, beside the organic wastes, sorting out between process and non-process, acidic and salt-bearing, tritiated and low tritiated streams and also according to their level of activity. A particular attention had to be paid to the analytical wastes, as their particularity is to contain not only a significant amount of radioactivity but also some fissile material and exotic chemicals which are useful for analytical purpose but unwanted in the main process mainly because of their corrosive and chelating properties. The analytical wastes are sorted out according to their activity level and fissile material content. On the one hand, a specific process has been developed to recover the bulk of plutonium from the analytical wastes. On the other hand, the foreseeable amount of unwanted chemicals (such as chloride ions) has been drastically reduced by carefully selecting all the analytical methods either by modification of already known methods or in some cases by working out new methods

An active learning representative subset selection method using net analyte signal

Science.gov (United States)

He, Zhonghai; Ma, Zhenhe; Luan, Jingmin; Cai, Xi

2018-05-01

To guarantee accurate predictions, representative samples are needed when building a calibration model for spectroscopic measurements. However, in general, it is not known whether a sample is representative prior to measuring its concentration, which is both time-consuming and expensive. In this paper, a method to determine whether a sample should be selected into a calibration set is presented. The selection is based on the difference of Euclidean norm of net analyte signal (NAS) vector between the candidate and existing samples. First, the concentrations and spectra of a group of samples are used to compute the projection matrix, NAS vector, and scalar values. Next, the NAS vectors of candidate samples are computed by multiplying projection matrix with spectra of samples. Scalar value of NAS is obtained by norm computation. The distance between the candidate set and the selected set is computed, and samples with the largest distance are added to selected set sequentially. Last, the concentration of the analyte is measured such that the sample can be used as a calibration sample. Using a validation test, it is shown that the presented method is more efficient than random selection. As a result, the amount of time and money spent on reference measurements is greatly reduced.

Quality Measures in Pre-Analytical Phase of Tissue Processing: Understanding Its Value in Histopathology.

Science.gov (United States)

Rao, Shalinee; Masilamani, Suresh; Sundaram, Sandhya; Duvuru, Prathiba; Swaminathan, Rajendiran

2016-01-01

Quality monitoring in histopathology unit is categorized into three phases, pre-analytical, analytical and post-analytical, to cover various steps in the entire test cycle. Review of literature on quality evaluation studies pertaining to histopathology revealed that earlier reports were mainly focused on analytical aspects with limited studies on assessment of pre-analytical phase. Pre-analytical phase encompasses several processing steps and handling of specimen/sample by multiple individuals, thus allowing enough scope for errors. Due to its critical nature and limited studies in the past to assess quality in pre-analytical phase, it deserves more attention. This study was undertaken to analyse and assess the quality parameters in pre-analytical phase in a histopathology laboratory. This was a retrospective study done on pre-analytical parameters in histopathology laboratory of a tertiary care centre on 18,626 tissue specimens received in 34 months. Registers and records were checked for efficiency and errors for pre-analytical quality variables: specimen identification, specimen in appropriate fixatives, lost specimens, daily internal quality control performance on staining, performance in inter-laboratory quality assessment program {External quality assurance program (EQAS)} and evaluation of internal non-conformities (NC) for other errors. The study revealed incorrect specimen labelling in 0.04%, 0.01% and 0.01% in 2007, 2008 and 2009 respectively. About 0.04%, 0.07% and 0.18% specimens were not sent in fixatives in 2007, 2008 and 2009 respectively. There was no incidence of specimen lost. A total of 113 non-conformities were identified out of which 92.9% belonged to the pre-analytical phase. The predominant NC (any deviation from normal standard which may generate an error and result in compromising with quality standards) identified was wrong labelling of slides. Performance in EQAS for pre-analytical phase was satisfactory in 6 of 9 cycles. A low incidence

Validation of analytical method for quality control of B12 Vitamin-10 000 injection

International Nuclear Information System (INIS)

Botet Garcia, Martha; Garcia Penna, Caridad Margarita; Troche Concepcion, Yenilen; Cannizares Arencibia, Yanara; Moreno Correoso, Barbara

2009-01-01

Analytical method reported by USA Pharmacopeia was validated for quality control of injectable B 1 2 Vitamin (10 000 U) by UV spectrophotometry because this is a simpler and low-cost method allowing quality control of finished product. Calibration curve was graphed at 60 to 140% interval, where it was linear with a correlation coefficient similar to 0, 9999; statistical test for interception and slope was considered non-significant. There was a recovery of 99.7 % in study concentrations interval where the Cochran (G) and Student(t) test were not significant too. Variation coefficient in repetition study was similar to 0.59 % for the 6 assayed replies, whereas in intermediate precision analysis, the Fisher and Student tests were not significant. Analytical method was linear, precise, specific and exact in study concentrations interval

Analytical method for determining colour intensities based on Cherenkov radiation colour quenching

Energy Technology Data Exchange (ETDEWEB)

Gonzalez-Gomez, C; Lopez-Gonzalez, J deD; Ferro-Garcia, M A [Univ. of Granada, Granada (Spain). Faculty of Sciences, Dept. of Inorganic Chemistry. Radiochemistry Section; Consejo Superior de Investigaciones Cientificas, Granada (Spain). Dept. of Chemical Research Coordinated Centre)

1983-01-01

A study was made for determining color intensities using as luminous non-monochromatic source produced by the Cherenkov emission in the walls of a glass capillary which acts as luminous source itself inside the colored solution to be evaluated. The reproducibility of this method has been compared with the spectrophotometric assay; the relative errors of both analytical methods have been calculated for different concentrations of congo red solution in the range of minimal error, according to Ringbom's criterion. The sensitivity of this analytical method has been studied for the two ..beta..-emitters employed: /sup 90/Sr//sup 90/Y and /sup 204/Tl.

An investigation of factors influencing indoor radon concentrations

International Nuclear Information System (INIS)

Majborn, B.; Soerensen, A.; Nielsen, S.P.; Boetter-Jensen, L.

1988-05-01

Variations in indoor radon concentrations and some influencing factors have been studied during a two-year period (1986-1987) in 16 almost identical single-family houses.The annual average radon concentration in the houses varied from about 50 to about 400 Bq/m 3 . Variations in soil characteristics and radon concentration in soil gas could not be directly related to the variations of the average indoor radon concentrations. Most of the houses showed a ''normal'' seasonal variation of the radon concentration with a maximum in the winter and minimum in the summer. A deviating seasonal variation was found in three of the houses. Hourly data obtained in one unoccupied house during a period of 2-1/2 months showed no or only weak correlations between the indoor radon concentration and meteorological factors. However, for most of the houses, the seasonal variation of the indoor radon concentration was well correlated with the average indoor-outdoor temperature difference on a 2-month basis. It was demonstrated that the radon concentration can be strongly reduced in the Risoe houses if a district-heating duct, which is connected to all the houses, is ventilated, so that a slightly lowered pressure is maintained in the duct. 5 taps., 24 ill. (author)

Optics of two-stage photovoltaic concentrators with dielectric second stages

Science.gov (United States)

Ning, Xiaohui; O'Gallagher, Joseph; Winston, Roland

1987-04-01

Two-stage photovoltaic concentrators with Fresnel lenses as primaries and dielectric totally internally reflecting nonimaging concentrators as secondaries are discussed. The general design principles of such two-stage systems are given. Their optical properties are studied and analyzed in detail using computer ray trace procedures. It is found that the two-stage concentrator offers not only a higher concentration or increased acceptance angle, but also a more uniform flux distribution on the photovoltaic cell than the point focusing Fresnel lens alone. Experimental measurements with a two-stage prototype module are presented and compared to the analytical predictions.

Optics of two-stage photovoltaic concentrators with dielectric second stages.

Science.gov (United States)

Ning, X; O'Gallagher, J; Winston, R

1987-04-01

Two-stage photovoltaic concentrators with Fresnel lenses as primaries and dielectric totally internally reflecting nonimaging concentrators as secondaries are discussed. The general design principles of such two-stage systems are given. Their optical properties are studied and analyzed in detail using computer ray trace procedures. It is found that the two-stage concentrator offers not only a higher concentration or increased acceptance angle, but also a more uniform flux distribution on the photovoltaic cell than the point focusing Fresnel lens alone. Experimental measurements with a two-stage prototype module are presented and compared to the analytical predictions.

Evaluating the efficiency of divestiture policy in promoting competitiveness using an analytical method and agent-based computational economics

International Nuclear Information System (INIS)

Rahimiyan, Morteza; Rajabi Mashhadi, Habib

2010-01-01

Choosing a desired policy for divestiture of dominant firms' generation assets has been a challenging task and open question for regulatory authority. To deal with this problem, in this paper, an analytical method and agent-based computational economics (ACE) approach are used for ex-ante analysis of divestiture policy in reducing market power. The analytical method is applied to solve a designed concentration boundary problem, even for situations where the cost data of generators are unknown. The concentration boundary problem is the problem of minimizing or maximizing market concentration subject to operation constraints of the electricity market. It is proved here that the market concentration corresponding to operation condition is certainly viable in an interval calculated by the analytical method. For situations where the cost function of generators is available, the ACE is used to model the electricity market. In ACE, each power producer's profit-maximization problem is solved by the computational approach of Q-learning. The power producer using the Q-learning method learns from past experiences to implicitly identify the market power, and find desired response in competing with the rivals. Both methods are applied in a multi-area power system and effects of different divestiture policies on market behavior are analyzed.

Evaluating the efficiency of divestiture policy in promoting competitiveness using an analytical method and agent-based computational economics

Energy Technology Data Exchange (ETDEWEB)

Rahimiyan, Morteza; Rajabi Mashhadi, Habib [Department of Electrical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad (Iran)

2010-03-15

Choosing a desired policy for divestiture of dominant firms' generation assets has been a challenging task and open question for regulatory authority. To deal with this problem, in this paper, an analytical method and agent-based computational economics (ACE) approach are used for ex-ante analysis of divestiture policy in reducing market power. The analytical method is applied to solve a designed concentration boundary problem, even for situations where the cost data of generators are unknown. The concentration boundary problem is the problem of minimizing or maximizing market concentration subject to operation constraints of the electricity market. It is proved here that the market concentration corresponding to operation condition is certainly viable in an interval calculated by the analytical method. For situations where the cost function of generators is available, the ACE is used to model the electricity market. In ACE, each power producer's profit-maximization problem is solved by the computational approach of Q-learning. The power producer using the Q-learning method learns from past experiences to implicitly identify the market power, and find desired response in competing with the rivals. Both methods are applied in a multi-area power system and effects of different divestiture policies on market behavior are analyzed. (author)

Fasting blood glucose and haemoglobin concentrations of healthy ...

African Journals Online (AJOL)

Menstruation is associated with loss of blood monthly in women of reproductive age. In some women this physiological phenomenon is also associated with some complaints such as menstrual pain, vomiting, and tiredness. We investigated the fasting blood glucose concentration and hemoglobin concentration before and ...

Analytic scattering kernels for neutron thermalization studies

International Nuclear Information System (INIS)

Sears, V.F.

1990-01-01

Current plans call for the inclusion of a liquid hydrogen or deuterium cold source in the NRU replacement vessel. This report is part of an ongoing study of neutron thermalization in such a cold source. Here, we develop a simple analytical model for the scattering kernel of monatomic and diatomic liquids. We also present the results of extensive numerical calculations based on this model for liquid hydrogen, liquid deuterium, and mixtures of the two. These calculations demonstrate the dependence of the scattering kernel on the incident and scattered-neutron energies, the behavior near rotational thresholds, the dependence on the centre-of-mass pair correlations, the dependence on the ortho concentration, and the dependence on the deuterium concentration in H 2 /D 2 mixtures. The total scattering cross sections are also calculated and compared with available experimental results

Croatian Analytical Terminology

Directory of Open Access Journals (Sweden)

Kastelan-Macan; M.

2008-04-01

Full Text Available Results of analytical research are necessary in all human activities. They are inevitable in making decisions in the environmental chemistry, agriculture, forestry, veterinary medicine, pharmaceutical industry, and biochemistry. Without analytical measurements the quality of materials and products cannot be assessed, so that analytical chemistry is an essential part of technical sciences and disciplines.The language of Croatian science, and analytical chemistry within it, was one of the goals of our predecessors. Due to the political situation, they did not succeed entirely, but for the scientists in independent Croatia this is a duty, because language is one of the most important features of the Croatian identity. The awareness of the need to introduce Croatian terminology was systematically developed in the second half of the 19th century, along with the founding of scientific societies and the wish of scientists to write their scientific works in Croatian, so that the results of their research may be applied in economy. Many authors of textbooks from the 19th and the first half of the 20th century contributed to Croatian analytical terminology (F. Rački, B. Šulek, P. Žulić, G. Pexidr, J. Domac, G. Janeček , F. Bubanović, V. Njegovan and others. M. DeŢelić published the first systematic chemical terminology in 1940, adjusted to the IUPAC recommendations. In the second half of 20th century textbooks in classic analytical chemistry were written by V. Marjanović-Krajovan, M. Gyiketta-Ogrizek, S. Žilić and others. I. Filipović wrote the General and Inorganic Chemistry textbook and the Laboratory Handbook (in collaboration with P. Sabioncello and contributed greatly to establishing the terminology in instrumental analytical methods.The source of Croatian nomenclature in modern analytical chemistry today are translated textbooks by Skoog, West and Holler, as well as by Günnzler i Gremlich, and original textbooks by S. Turina, Z. �

Analytic tests and their relation to jet fuel thermal stability

Energy Technology Data Exchange (ETDEWEB)

Heneghan, S.P.; Kauffman, R.E. [Univ. of Dayton Research Institute, OH (United States)

1995-05-01

The evaluation of jet fuel thermal stability (TS) by simple analytic procedures has long been a goal of fuels chemists. The reason is obvious: if the analytic chemist can determine which types of material cause his test to respond, the refiners will know which materials to remove to improve stability. Complicating this quest is the lack of an acceptable quantitative TS test with which to compare any analytic procedures. To circumvent this problem, we recently compiled the results of TS tests for 12 fuels using six separate test procedures. The results covering a range of flow and temperature conditions show that TS is not as dependent on test conditions as previously thought. Also, comparing the results from these tests with several analytic procedures shows that either a measure of the number of phenols or the total sulfur present in jet fuels is strongly indicative of the TS. The phenols have been measured using a cyclic voltammetry technique and the polar material by gas chromatography (atomic emission detection) following a solid phase extraction on silica gel. The polar material has been identified as mainly phenols (by mass spectrometry identification). Measures of the total acid number or peroxide concentration have little correlation with TS.

Analytical Web Tool for CERES Products

Science.gov (United States)

Mitrescu, C.; Chu, C.; Doelling, D.

2012-12-01

The CERES project provides the community climate quality observed TOA fluxes, consistent cloud properties, and computed profile and surface fluxes. The 11-year long data set proves invaluable for remote sensing and climate modeling communities for annual global mean energy, meridianal heat transport, consistent cloud and fluxes and climate trends studies. Moreover, a broader audience interested in Earth's radiative properties such as green energy, health and environmental companies have showed their interest in CERES derived products. A few years ago, the CERES team start developing a new web-based Ordering Tool tailored for this wide diversity of users. Recognizing the potential that web-2.0 technologies can offer to both Quality Control (QC) and scientific data visualization and manipulation, the CERES team began introducing a series of specialized functions that addresses the above. As such, displaying an attractive, easy to use modern web-based format, the Ordering Tool added the following analytical functions: i) 1-D Histograms to display the distribution of the data field to identify outliers that are useful for QC purposes; ii) an "Anomaly" map that shows the regional differences between the current month and the climatological monthly mean; iii) a 2-D Histogram that can identify either potential problems with the data (i.e. QC function) or provides a global view of trends and/or correlations between various CERES flux, cloud, aerosol, and atmospheric properties. The large volume and diversity of data, together with the on-the-fly execution were the main challenges that had to be tackle with. Depending on the application, the execution was done on either the browser side or the server side with the help of auxiliary files. Additional challenges came from the use of various open source applications, the multitude of CERES products and the seamless transition from previous development. For the future, we plan on expanding the analytical capabilities of the

Precision profiles and analytic reliability of radioimmunologic methods

International Nuclear Information System (INIS)

Yaneva, Z.; Popova, Yu.

1991-01-01

The aim of the present study is to investigate and compare some methods for creation of 'precision profiles' (PP) and to clarify their possibilities for determining the analytical reliability of RIA. Only methods without complicated mathematical calculations has been used. The reproducibility in serums with a concentration of the determinable hormone in the whole range of the calibration curve has been studied. The radioimmunoassay has been performed with TSH-RIA set (ex East Germany), and comparative evaluations - with commercial sets of HOECHST (Germany) and AMERSHAM (GB). Three methods for obtaining the relationship concentration (IU/l) -reproducibility (C.V.,%) are used and a comparison is made of their corresponding profiles: preliminary rough profile, Rodbard-PP and Ekins-PP. It is concluded that the creation of a precision profile is obligatory and the method of its construction does not influence the relationship's course. PP allows to determine concentration range giving stable results which improves the efficiency of the analitical work. 16 refs., 4 figs

Monte Carlo and analytic simulations in nanoparticle-enhanced radiation therapy

Directory of Open Access Journals (Sweden)

Paro AD

2016-09-01

Full Text Available Autumn D Paro,1 Mainul Hossain,2 Thomas J Webster,1,3,4 Ming Su1,4 1Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 2NanoScience Technology Center and School of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida, USA; 3Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia; 4Wenzhou Institute of Biomaterials and Engineering, Chinese Academy of Science, Wenzhou Medical University, Zhejiang, People’s Republic of China Abstract: Analytical and Monte Carlo simulations have been used to predict dose enhancement factors in nanoparticle-enhanced X-ray radiation therapy. Both simulations predict an increase in dose enhancement in the presence of nanoparticles, but the two methods predict different levels of enhancement over the studied energy, nanoparticle materials, and concentration regime for several reasons. The Monte Carlo simulation calculates energy deposited by electrons and photons, while the analytical one only calculates energy deposited by source photons and photoelectrons; the Monte Carlo simulation accounts for electron–hole recombination, while the analytical one does not; and the Monte Carlo simulation randomly samples photon or electron path and accounts for particle interactions, while the analytical simulation assumes a linear trajectory. This study demonstrates that the Monte Carlo simulation will be a better choice to evaluate dose enhancement with nanoparticles in radiation therapy. Keywords: nanoparticle, dose enhancement, Monte Carlo simulation, analytical simulation, radiation therapy, tumor cell, X-ray 

Fluorescence measurement of atomic oxygen concentration in a dielectric barrier discharge

Science.gov (United States)

Dvořák, P.; Mrkvičková, M.; Obrusník, A.; Kratzer, J.; Dědina, J.; Procházka, V.

2017-06-01

Concentration of atomic oxygen was measured in a volume dielectric barrier discharge (DBD) ignited in mixtures of Ar + O2(+ H2) at atmospheric pressure. Two-photon absorption laser induced fluorescence (TALIF) of atomic oxygen was used and this method was calibrated by TALIF of Xe in a mixture of argon and a trace of xenon. The calibration was performed at atmospheric pressure and it was shown that quenching by three-body collisions has negligible effect on the life time of excited Xe atoms. The concentration of atomic oxygen in the DBD was around 1021 m-3 and it was stable during the whole discharge period. The concentration did not depend much on the electric power delivered to the discharge provided that the power was sufficiently high so that the visible discharge filled the whole reactor volume. Both the addition of hydrogen or replacing of argon by helium led to a significant decrease of atomic oxygen concentration. The TALIF measurements of O concentration levels in the DBD plasma performed in this work are made use of e.g. in the field analytical chemistry. The results contribute to understanding the processes of analyte hydride preconcentration and subsequent atomization in the field of trace element analysis where DBD plasma atomizers are employed.

Determination of natural in vivo noble-gas concentrations in human blood.

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Yama Tomonaga

Full Text Available Although the naturally occurring atmospheric noble gases He, Ne, Ar, Kr, and Xe possess great potential as tracers for studying gas exchange in living beings, no direct analytical technique exists for simultaneously determining the absolute concentrations of these noble gases in body fluids in vivo. In this study, using human blood as an example, the absolute concentrations of all stable atmospheric noble gases were measured simultaneously by combining and adapting two analytical methods recently developed for geochemical research purposes. The partition coefficients determined between blood and air, and between blood plasma and red blood cells, agree with values from the literature. While the noble-gas concentrations in the plasma agree rather well with the expected solubility equilibrium concentrations for air-saturated water, the red blood cells are characterized by a distinct supersaturation pattern, in which the gas excess increases in proportion to the atomic mass of the noble-gas species, indicating adsorption on to the red blood cells. This study shows that the absolute concentrations of noble gases in body fluids can be easily measured using geochemical techniques that rely only on standard materials and equipment, and for which the underlying concepts are already well established in the field of noble-gas geochemistry.

MASTERS OF ANALYTICAL TRADECRAFT: CERTIFYING THE STANDARDS AND ANALYTIC RIGOR OF INTELLIGENCE PRODUCTS

Science.gov (United States)

2016-04-01

AU/ACSC/2016 AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY MASTERS OF ANALYTICAL TRADECRAFT: CERTIFYING THE STANDARDS AND ANALYTIC RIGOR OF...establishing unit level certified Masters of Analytic Tradecraft (MAT) analysts to be trained and entrusted to evaluate and rate the standards and...cues) ideally should meet or exceed effective rigor (based on analytical process).4 To accomplish this, decision makers should not be left to their

Modeling of the anode side of a direct methanol fuel cell with analytical solutions

International Nuclear Information System (INIS)

Mosquera, Martin A.; Lizcano-Valbuena, William H.

2009-01-01

In this work, analytical solutions were derived (for any methanol oxidation reaction order) for the profiles of methanol concentration and proton current density, by assuming diffusion mass transport mechanism, Tafel kinetics, and fast proton transport in the anodic catalyst layer of a direct methanol fuel cell. An expression for the Thiele modulus that allows to express the anodic overpotential as a function of the cell current and kinetic and mass transfer parameters was obtained. For high cell current densities, it was found that the Thiele modulus (φ 2 ) varies quadratically with cell current density; yielding a simple correlation between anodic overpotential and cell current density. Analytical solutions were derived for the profiles of both local methanol concentration in the catalyst layer and local anodic current density in the catalyst layer. Under the assumptions of the model presented here, in general, the local methanol concentration in the catalyst layer cannot be expressed as an explicit function of the position in the layer. In spite of this, the equations presented here for the anodic overpotential allow the derivation of new semi-empirical equations

Analytical evaluation of fission product sensitivities

International Nuclear Information System (INIS)

Sola, A.

1977-01-01

Evaluating the concentration of a fission product produced in a reactor requires the knowledge of a fairly large number of variables. Sensitivity studies were made to ascertain the important variables. Analytical formulae were developed sufficiently simple to allow numerical computations. Some simplified formulas are also given and they are applied to the following isotopes: 80 Se, 82 Se, 81 Br, 82 Br, 82 Kr, 83 Kr, 84 Kr, 85 Kr, 86 Kr. Their sensitivities to capture cross sections, fission yields, ratios of activation cross sections, half-lives (during and after irradiation), branching ratios, as well as to the neutron flux and to the time are considered

Reference Intervals of Hematology and Clinical Chemistry Analytes for 1-Year-Old Korean Children.

Science.gov (United States)

Lee, Hye Ryun; Shin, Sue; Yoon, Jong Hyun; Roh, Eun Youn; Chang, Ju Young

2016-09-01

Reference intervals need to be established according to age. We established reference intervals of hematology and chemistry from community-based healthy 1-yr-old children and analyzed their iron status according to the feeding methods during the first six months after birth. A total of 887 children who received a medical check-up between 2010 and 2014 at Boramae Hospital (Seoul, Korea) were enrolled. A total of 534 children (247 boys and 287 girls) were enrolled as reference individuals after the exclusion of data obtained from children with suspected iron deficiency. Hematology and clinical chemistry analytes were measured, and the reference value of each analyte was estimated by using parametric (mean±2 SD) or nonparametric methods (2.5-97.5th percentile). Iron, total iron-binding capacity, and ferritin were measured, and transferrin saturation was calculated. As there were no differences in the mean values between boys and girls, we established the reference intervals for 1-yr-old children regardless of sex. The analysis of serum iron status according to feeding methods during the first six months revealed higher iron, ferritin, and transferrin saturation levels in children exclusively or mainly fed formula than in children exclusively or mainly fed breast milk. We established reference intervals of hematology and clinical chemistry analytes from community-based healthy children at one year of age. These reference intervals will be useful for interpreting results of medical check-ups at one year of age.

Analytical validation of a new point-of-care assay for serum amyloid A in horses.

Science.gov (United States)

Schwartz, D; Pusterla, N; Jacobsen, S; Christopher, M M

2018-01-17

Serum amyloid A (SAA) is a major acute phase protein in horses. A new point-of-care (POC) test for SAA (Stablelab) is available, but studies evaluating its analytical accuracy are lacking. To evaluate the analytical performance of the SAA POC test by 1) determining linearity and precision, 2) comparing results in whole blood with those in serum or plasma, and 3) comparing POC results with those obtained using a previously validated turbidimetric immunoassay (TIA). Assay validation. Analytical validation of the POC test was done in accordance with American Society of Veterinary Clinical Pathology guidelines using residual equine serum/plasma and whole blood samples from the Clinical Pathology Laboratory at the University of California-Davis. A TIA was used as the reference method. We also evaluated the effect of haematocrit (HCT). The POC test was linear for SAA concentrations of up to at least 1000 μg/mL (r = 0.991). Intra-assay CVs were 13, 18 and 15% at high (782 μg/mL), intermediate (116 μg/mL) and low (64 μg/mL) concentrations. Inter-assay (inter-batch) CVs were 45, 14 and 15% at high (1372 μg/mL), intermediate (140 μg/mL) and low (56 μg/mL) concentrations. SAA results in whole blood were significantly lower than those in serum/plasma (P = 0.0002), but were positively correlated (r = 0.908) and not affected by HCT (P = 0.261); proportional negative bias was observed in samples with SAA>500 μg/mL. The difference between methods exceeded the 95% confidence interval of the combined imprecision of both methods (15%). Analytical validation could not be performed in whole blood, the sample most likely to be used stall side. The POC test has acceptable accuracy and precision in equine serum/plasma with SAA concentrations of up to at least 1000 μg/mL. Low inter-batch precision at high concentrations may affect serial measurements, and the use of the same test batch and sample type (serum/plasma or whole blood) is recommended. Comparison of results between the

Approximate analytical relationships for linear optimal aeroelastic flight control laws

Science.gov (United States)

Kassem, Ayman Hamdy

1998-09-01

This dissertation introduces new methods to uncover functional relationships between design parameters of a contemporary control design technique and the resulting closed-loop properties. Three new methods are developed for generating such relationships through analytical expressions: the Direct Eigen-Based Technique, the Order of Magnitude Technique, and the Cost Function Imbedding Technique. Efforts concentrated on the linear-quadratic state-feedback control-design technique applied to an aeroelastic flight control task. For this specific application, simple and accurate analytical expressions for the closed-loop eigenvalues and zeros in terms of basic parameters such as stability and control derivatives, structural vibration damping and natural frequency, and cost function weights are generated. These expressions explicitly indicate how the weights augment the short period and aeroelastic modes, as well as the closed-loop zeros, and by what physical mechanism. The analytical expressions are used to address topics such as damping, nonminimum phase behavior, stability, and performance with robustness considerations, and design modifications. This type of knowledge is invaluable to the flight control designer and would be more difficult to formulate when obtained from numerical-based sensitivity analysis.

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

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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.

Simultaneous in-line concentration for spectrophotometric determination of cations and anions

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Rocha Fábio R. P

2004-01-01

Full Text Available A flow system is proposed for simultaneous in-line concentration of cations and anions. A sliding-bar commutator was employed to insert an anion and a cation exchange column into a flowing sample stream for serial retention of the analytes. In the injector alternative position, different solutions flowed through the columns for parallel elution of the species in different analytical paths. Three-way solenoid valves allowed the intermittent reagent introduction in the sample zones. Signals were measured by employing two flow-through LED-based detectors. The simultaneous retention of the sample zones in coiled reactors can be also performed to increase the residence time and the analyte conversion rate. The analytical potentiality was demonstrated by the in-line concentration of ammonium and phosphate followed by spectrophotometric detection. For a 90 s loading time, the sampling rate was estimated as 40 determinations per hour, which is three-fold higher than the obtained without performing the tasks simultaneously. Enrichment factors of 8.0 and 18 were estimated for phosphate and ammonium, respectively, yielding detection limits of 1 mg L-1 PO4(3- and 1 mg L-1 NH4+ (99.7% confidence level. The reagent consumption was lower than 2 mg per determination. Results for freshwater samples agreed with the obtained by reference APHA procedures at the 95% confidence level.

PLE in the analysis of plant compounds. Part II: One-cycle PLE in determining total amount of analyte in plant material.

Science.gov (United States)

Dawidowicz, Andrzej L; Wianowska, Dorota

2005-04-29

Pressurised liquid extraction (PLE) is recognised as one of the most effective sample preparation methods. Despite the enhanced extraction power of PLE, the full recovery of an analyte from plant material may require multiple extractions of the same sample. The presented investigations show the possibility of estimating the true concentration value of an analyte in plant material employing one-cycle PLE in which plant samples of different weight are used. The performed experiments show a linear dependence between the reciprocal value of the analyte amount (E*), extracted in single-step PLE from a plant matrix, and the ratio of plant material mass to extrahent volume (m(p)/V(s)). Hence, time-consuming multi-step PLE can be replaced by a few single-step PLEs performed at different (m(p)/V(s)) ratios. The concentrations of rutin in Sambucus nigra L. and caffeine in tea and coffee estimated by means of the tested procedure are almost the same as their concentrations estimated by multiple PLE.

Uncertainty of pesticide residue concentration determined from ordinary and weighted linear regression curve.

Science.gov (United States)

Yolci Omeroglu, Perihan; Ambrus, Árpad; Boyacioglu, Dilek

2018-03-28

Determination of pesticide residues is based on calibration curves constructed for each batch of analysis. Calibration standard solutions are prepared from a known amount of reference material at different concentration levels covering the concentration range of the analyte in the analysed samples. In the scope of this study, the applicability of both ordinary linear and weighted linear regression (OLR and WLR) for pesticide residue analysis was investigated. We used 782 multipoint calibration curves obtained for 72 different analytical batches with high-pressure liquid chromatography equipped with an ultraviolet detector, and gas chromatography with electron capture, nitrogen phosphorus or mass spectrophotometer detectors. Quality criteria of the linear curves including regression coefficient, standard deviation of relative residuals and deviation of back calculated concentrations were calculated both for WLR and OLR methods. Moreover, the relative uncertainty of the predicted analyte concentration was estimated for both methods. It was concluded that calibration curve based on WLR complies with all the quality criteria set by international guidelines compared to those calculated with OLR. It means that all the data fit well with WLR for pesticide residue analysis. It was estimated that, regardless of the actual concentration range of the calibration, relative uncertainty at the lowest calibrated level ranged between 0.3% and 113.7% for OLR and between 0.2% and 22.1% for WLR. At or above 1/3 of the calibrated range, uncertainty of calibration curve ranged between 0.1% and 16.3% for OLR and 0% and 12.2% for WLR, and therefore, the two methods gave comparable results.

Analytical solution and simplified analysis of coupled parent-daughter steady-state transport with multirate mass transfer

Science.gov (United States)

R. Haggerty

2013-01-01

In this technical note, a steady-state analytical solution of concentrations of a parent solute reacting to a daughter solute, both of which are undergoing transport and multirate mass transfer, is presented. Although the governing equations are complicated, the resulting solution can be expressed in simple terms. A function of the ratio of concentrations, In (daughter...

Sensibility analysis of the effect of various key parameters on fission product concentration mass number 127 to 132 and Xe - 133 m)

International Nuclear Information System (INIS)

Sola, A.

1978-01-01

An analytical sensitivity analysis has been made of the effect' of various parameters on the evaluation of fission product concentration. Such parameters include cross sections, decay constants, branching ratios, fission yields, flux and time. The formulae are applied to isotopes of the Antimony, Tellurium, Iodine and Xenon series. The agreement between analytically obtained data and that derived from a computer evaluated model is good, suggesting that the analytical representation includes all the important parameters useful to the evaluation of the fission product concentrations

Maternal Knowledge and Attitude toward Exclusive Breast Milk Feeding (BMF in the First 6 Months of Infant Life in Mashhad

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Bibi Leila Hoseini

2014-01-01

Full Text Available Introduction: Breast milk is a complete food for growing children until 6 months of age, and mothers, as the most important child health care, play a decisive role in their growth. So promoting  their attitude toward the benefits of breastfeeding ensures guarantee child health in the future. This study aimed to assess maternal knowledge and attitude of Mashhad toward exclusive BMF in the first 6 months of infant life.   Materials and Methods: This cross-sectional descriptive-analytic study was conducted on 126 mothers who referring to Mashhad health-care centers for monitoring their 6-24 month year old infants. They completed questionnaire. Participants were selected by cluster and simple random sampling. Data were analyzed by descriptive- analytic tests and using SPSS 11.5.   Results: Mean score of maternal attitude toward exclusive BMF was 14.32±5.28 (out of 28 and maternal knowledge score toward advantages of breast milk was 19.59±4.80 (out of 28. The incidence of exclusive BMF in the first 6 months of life study was 73.8%. Child growth was as follows: excellent growth (5.6% and good growth (42.1%. ANOVA showed a significant difference between parents' education and maternal attitude towards exclusive BMF; whatever higher education of parents, more positive maternal attitude towards exclusive BMF (P

Maternal Knowledge and Attitude toward Exclusive Breast Milk Feeding (BMF in the First 6 Months of Infant in Mashhad-Iran

Directory of Open Access Journals (Sweden)

M Saeidi

2014-04-01

Full Text Available Introduction: Breast milk is a complete food for growing children until 6 months of age, and mothers, as the most important child health care, play a decisive role in their growth. So promoting  their attitude toward the benefits of breastfeeding ensures guarantee child health in the future. This study aimed to assess maternal knowledge and attitude of Mashhad toward exclusive BMF in the first 6 months of infant life.   Materials and Methods: This cross-sectional descriptive-analytic study was conducted on 126 mothers who referring to Mashhad health-care centers for monitoring their 6-24 month year old infants. They completed questionnaire. Participants were selected by cluster and simple random sampling. Data were analyzed by descriptive- analytic tests and using SPSS 11.5.   Results: Mean score of maternal attitude toward exclusive BMF was 14.32±5.28 (out of 28 and maternal knowledge score toward advantages of breast milk was 19.59±4.80 (out of 28. The incidence of exclusive BMF in the first 6 months of life study was 73.8%. Child growth was as follows: excellent growth (5.6% and good growth (42.1%. ANOVA showed a significant difference between parents' education and maternal attitude towards exclusive BMF; whatever higher education of parents, more positive maternal attitude towards exclusive BMF (P

Solution standards for quality control of nuclear-material analytical measurements

International Nuclear Information System (INIS)

Clark, J.P.

1981-01-01

Analytical chemistry measurement control depends upon reliable solution standards. At the Savannah River Plant Control Laboratory over a thousand analytical measurements are made daily for process control, product specification, accountability, and nuclear safety. Large quantities of solution standards are required for a measurement quality control program covering the many different analytical chemistry methods. Savannah River Plant produced uranium, plutonium, neptunium, and americium metals or oxides are dissolved to prepare stock solutions for working or Quality Control Standards (QCS). Because extensive analytical effort is required to characterize or confirm these solutions, they are prepared in large quantities. These stock solutions are diluted and blended with different chemicals and/or each other to synthesize QCS that match the matrices of different process streams. The target uncertainty of a standard's reference value is 10% of the limit of error of the methods used for routine measurements. Standard Reference Materials from NBS are used according to special procedures to calibrate the methods used in measuring the uranium and plutonium standards so traceability can be established. Special precautions are required to minimize the effects of temperature, radiolysis, and evaporation. Standard reference values are periodically corrected to eliminate systematic errors caused by evaporation or decay products. Measurement control is achieved by requiring analysts to analyze a blind QCS each shift a measurement system is used on plant samples. Computer evaluation determines whether or not a measurement is within the +- 3 sigma control limits. Monthly evaluations of the QCS measurements are made to determine current bias correction factors for accountability measurements and detect significant changes in the bias and precision statistics. The evaluations are also used to plan activities for improving the reliability of the analytical chemistry measurements

Effect of castration at 10 months of age on growth physiology and behavior of male feral beef cattle.

Science.gov (United States)

Álvarez-Rodríguez, Javier; Albertí, Pere; Ripoll, Guillermo; Blasco, Isabel; Sanz, Albina

2017-07-01

This study compared the growth performance, plasma testosterone and cortisol levels around castration at 10 months of age, and plasma insulin-like growth factor (IGF)-I concentration and flight speed, in intact bulls and steers from 10 to 21 months of age in a feral Spanish breed. Fourteen bulls (366.5 ± 48.5 kg live weight) were assigned at random to one of two treatments: surgically castrated (steers) or intact (bulls), and submitted to an identical fattening period. Steers reared until heavy live weights (21 months of age) grew slowly and had lower plasma IGF-I concentrations than intact bulls. These differences were mainly highlighted the month after surgery (11 months of age) and the last part of the fattening period (from 19 to 21 months of age). After surgical castration (11 and 12 months of age), steers showed a tendency to display greater flight speed values than intact bulls but baseline plasma cortisol concentration did not differ between groups at this time. At the end, steers and bulls reached nearly similar temperament, as flight speed did not differ between them. The results confirm the role of IGF-I as a key anabolic hormone in male beef cattle and thus it may reflect growth differences due to altered sex steroids production. © 2016 Japanese Society of Animal Science.

Analysis of the distributions of hourly NO2 concentrations contributing to annual average NO2 concentrations across the European monitoring network between 2000 and 2014

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C. S. Malley

2018-03-01

Full Text Available Exposure to nitrogen dioxide (NO2 is associated with negative human health effects, both for short-term peak concentrations and from long-term exposure to a wider range of NO2 concentrations. For the latter, the European Union has established an air quality limit value of 40 µg m−3 as an annual average. However, factors such as proximity and strength of local emissions, atmospheric chemistry, and meteorological conditions mean that there is substantial variation in the hourly NO2 concentrations contributing to an annual average concentration. The aim of this analysis was to quantify the nature of this variation at thousands of monitoring sites across Europe through the calculation of a standard set of chemical climatology statistics. Specifically, at each monitoring site that satisfied data capture criteria for inclusion in this analysis, annual NO2 concentrations, as well as the percentage contribution from each month, hour of the day, and hourly NO2 concentrations divided into 5 µg m−3 bins were calculated. Across Europe, 2010–2014 average annual NO2 concentrations (NO2AA exceeded the annual NO2 limit value at 8 % of > 2500 monitoring sites. The application of this chemical climatology approach showed that sites with distinct monthly, hour of day, and hourly NO2 concentration bin contributions to NO2AA were not grouped into specific regions of Europe, furthermore, within relatively small geographic regions there were sites with similar NO2AA, but with differences in these contributions. Specifically, at sites with highest NO2AA, there were generally similar contributions from across the year, but there were also differences in the contribution of peak vs. moderate hourly NO2 concentrations to NO2AA, and from different hours across the day. Trends between 2000 and 2014 for 259 sites indicate that, in general, the contribution to NO2AA from winter months has increased, as has the contribution from the rush-hour periods of

Analysis of the distributions of hourly NO2 concentrations contributing to annual average NO2 concentrations across the European monitoring network between 2000 and 2014

Science.gov (United States)

Malley, Christopher S.; von Schneidemesser, Erika; Moller, Sarah; Braban, Christine F.; Hicks, W. Kevin; Heal, Mathew R.

2018-03-01

Exposure to nitrogen dioxide (NO2) is associated with negative human health effects, both for short-term peak concentrations and from long-term exposure to a wider range of NO2 concentrations. For the latter, the European Union has established an air quality limit value of 40 µg m-3 as an annual average. However, factors such as proximity and strength of local emissions, atmospheric chemistry, and meteorological conditions mean that there is substantial variation in the hourly NO2 concentrations contributing to an annual average concentration. The aim of this analysis was to quantify the nature of this variation at thousands of monitoring sites across Europe through the calculation of a standard set of chemical climatology statistics. Specifically, at each monitoring site that satisfied data capture criteria for inclusion in this analysis, annual NO2 concentrations, as well as the percentage contribution from each month, hour of the day, and hourly NO2 concentrations divided into 5 µg m-3 bins were calculated. Across Europe, 2010-2014 average annual NO2 concentrations (NO2AA) exceeded the annual NO2 limit value at 8 % of > 2500 monitoring sites. The application of this chemical climatology approach showed that sites with distinct monthly, hour of day, and hourly NO2 concentration bin contributions to NO2AA were not grouped into specific regions of Europe, furthermore, within relatively small geographic regions there were sites with similar NO2AA, but with differences in these contributions. Specifically, at sites with highest NO2AA, there were generally similar contributions from across the year, but there were also differences in the contribution of peak vs. moderate hourly NO2 concentrations to NO2AA, and from different hours across the day. Trends between 2000 and 2014 for 259 sites indicate that, in general, the contribution to NO2AA from winter months has increased, as has the contribution from the rush-hour periods of the day, while the contribution from

Optimization in the nuclear fuel cycle II: Concentration of alpha emitters in the air

International Nuclear Information System (INIS)

Pereira, W.S.; Silva, A.X.; Lopes, J.M.; Carmo, A.S.; Mello, C.R.; Fernandes, T.S.; Kelecom, A.

2017-01-01

Optimization is one of the bases of radioprotection and aims to move doses away from the dose limit that is the borderline of acceptable radiological risk. The work aims to use the monitoring of the concentration of alpha emitters in the air as a tool of the optimization process. We analyzed 27 sampling points of airborne alpha concentration in a nuclear fuel cycle facility. The monthly averages were considered statistically different, the highest in the month of February and the lowest in the month of August. All other months were found to have identical mean activity concentration values. Regarding the sampling points, the points with the highest averages were points 12, 15 and 9. These points were indicated for the beginning of the optimization process. Analysis of the production of the facility should be performed to verify possible correlations between production and concentration of alpha emitters in the air

Assessing Analytical Similarity of Proposed Amgen Biosimilar ABP 501 to Adalimumab.

Science.gov (United States)

Liu, Jennifer; Eris, Tamer; Li, Cynthia; Cao, Shawn; Kuhns, Scott

2016-08-01

ABP 501 is being developed as a biosimilar to adalimumab. Comprehensive comparative analytical characterization studies have been conducted and completed. The objective of this study was to assess analytical similarity between ABP 501 and two adalimumab reference products (RPs), licensed by the United States Food and Drug Administration (adalimumab [US]) and authorized by the European Union (adalimumab [EU]), using state-of-the-art analytical methods. Comprehensive analytical characterization incorporating orthogonal analytical techniques was used to compare products. Physicochemical property comparisons comprised the primary structure related to amino acid sequence and post-translational modifications including glycans; higher-order structure; primary biological properties mediated by target and receptor binding; product-related substances and impurities; host-cell impurities; general properties of the finished drug product, including strength and formulation; subvisible and submicron particles and aggregates; and forced thermal degradation. ABP 501 had the same amino acid sequence and similar post-translational modification profiles compared with adalimumab RPs. Primary structure, higher-order structure, and biological activities were similar for the three products. Product-related size and charge variants and aggregate and particle levels were also similar. ABP 501 had very low residual host-cell protein and DNA. The finished ABP 501 drug product has the same strength with regard to protein concentration and fill volume as adalimumab RPs. ABP 501 and the RPs had a similar stability profile both in normal storage and thermal stress conditions. Based on the comprehensive analytical similarity assessment, ABP 501 was found to be similar to adalimumab with respect to physicochemical and biological properties.

Development of an analytical procedure for plutonium in the concentration range of femtogram/gram and its application to environmental samples

International Nuclear Information System (INIS)

Schuettelkopf, H.

1981-09-01

To study the behaviour of plutonium in the environment and to measure plutonium in the vicinity of nuclear facilities, a quick, sensitive analytical method is required which can be applied to all sample materials found in the environment. For a sediment contaminated with plutonium a boiling out method using first HNO 3 /HF and subsequently HNO 3 /Al(NO 3 ) 3 was found to be successful. The leaching solution was then extracted by TOPO and the plutonium backextracted by ascorbic acid/HCl. Some different purification steps and finally electroplating using ammonium oxalate led to an optimum sample for α- spectroscopic determination of plutonium. An analytical method was worked out for plutonium which can be applied to all materials found in the environment. The sample size is 100 g but it might also be much greater. The average chemical yield is 70 and 80%. The detection limit for soil samples is 0.1 fCi/g and for plant samples 0.5 fCi/g. One technician can perform eight analyses per working day. The analytical procedure was applied to a large number of environmental samples and the results of these analyses are indicated. (orig./RB) [de

Low plasma triiodothyronine concentrations and outcome in preterm infants.

Science.gov (United States)

Lucas, A; Rennie, J; Baker, B A; Morley, R

1988-01-01

A major association has been found between low plasma triiodothyronine concentrations in preterm neonates and their later developmental outcome. Plasma triiodothyronine concentration was measured longitudinally in 280 preterm infants below 1850 g birth weight. Babies whose lowest recorded concentration was less than 0.3 nmol/l had, at 18 months' corrected age, 8.3 and 7.4 point disadvantages in Bayley mental and motor scales and a 8.6 point disadvantage on the academic scale of Developmental Profile II, even after adjusting for a range of antenatal and neonatal factors known to influence later development. Low concentrations of triiodothyronine were strongly associated with infant mortality, but not after adjusting for the presence of respiratory illness. There was no association between plasma triiodothyronine concentrations and somatic growth up to 18 months, and no association with necrotising enterocolitis or later cerebral palsy. Data on postnatal changes in plasma triiodothyronine concentrations are presented for reference purposes. While cited reference ranges for plasma triiodothyronine concentration appear suitable for well infants above 1500 g birth weight, smaller or ill babies often have very low values for many weeks. Our data are relevant to the debate on endocrine 'replacement' treatment in premature babies. PMID:2461683

Estimated exposures to perfluorinated compounds in infancy predict attenuated vaccine antibody concentrations at age 5-years

DEFF Research Database (Denmark)

Grandjean, Philippe; Heilmann, Carsten; Weihe, Pal

2017-01-01

Perfluorinated alkylate substances (PFASs) are highly persistent and may cause immunotoxic effects. PFAS-associated attenuated antibody responses to childhood vaccines may be affected by PFAS exposures during infancy, where breastfeeding adds to PFAS exposures. Of 490 members of a Faroese birth...... cohort, 275 and 349 participated in clinical examinations and provided blood samples at ages 18 months and 5 years. PFAS concentrations were measured at birth and at the clinical examinations. Using information on duration of breastfeeding, serum-PFAS concentration profiles during infancy were estimated......, with decreases by up to about 20% for each two-fold higher exposure, while associations for serum concentrations at ages 18 months and 5 years were weaker. Modeling of serum-PFAS concentration showed levels for age 18 months that were similar to those measured. Concentrations estimated for ages 3 and 6 months...

Multi-analytical assessment of iron and steel slag characteristics to estimate the removal of metalloids from contaminated water.

Science.gov (United States)

Mercado-Borrayo, B M; Schouwenaars, R; González-Chávez, J L; Ramírez-Zamora, R M

2013-01-01

A multi-analytical approach was used to develop a mathematical regression model to calculate the residual concentration of borate ions in water present at high initial content, as a function of the main physicochemical, mineralogical and electrokinetic characteristics after adsorption on five different types of iron and steel slag. The analytical techniques applied and slag properties obtained in this work were: X-ray Fluorescence for the identification of the main chemical compounds, X-ray Diffraction to determine crystalline phases, physical adsorption of nitrogen for the quantification of textural properties and zeta-potential for electrokinetic measurements of slag particles. Adsorption tests were carried out using the bottle-point technique and a highly concentrated borate solution (700 mg B/L) at pH 10, with a slag dose of 10 g/L. An excellent correlation between the residual concentration of boron and three independent variables (content of magnesium oxide, zeta potential and specific surface area) was established for the five types of slag tested in this work. This shows that the methodology based on a multi-analytical approach is a very strong and useful tool to estimate the performance of iron and steel slag as adsorbent of metalloids.

Business analytics a practitioner's guide

CERN Document Server

Saxena, Rahul

2013-01-01

This book provides a guide to businesses on how to use analytics to help drive from ideas to execution. Analytics used in this way provides "full lifecycle support" for business and helps during all stages of management decision-making and execution.The framework presented in the book enables the effective interplay of business, analytics, and information technology (business intelligence) both to leverage analytics for competitive advantage and to embed the use of business analytics into the business culture. It lays out an approach for analytics, describes the processes used, and provides gu

eAnalytics: Dynamic Web-based Analytics for the Energy Industry

Directory of Open Access Journals (Sweden)

Paul Govan

2016-11-01

Full Text Available eAnalytics is a web application built on top of R that provides dynamic data analytics to energy industry stakeholders. The application allows users to dynamically manipulate chart data and style through the Shiny package’s reactive framework. eAnalytics currently supports a number of features including interactive datatables, dynamic charting capabilities, and the ability to save, download, or export information for further use. Going forward, the goal for this project is that it will serve as a research hub for discovering new relationships in the data. The application is illustrated with a simple tutorial of the user interface design.

Analytical evaluation of the novel Lumipulse G BRAHMS procalcitonin immunoassay

Directory of Open Access Journals (Sweden)

Orazio Ruzzenente

2016-12-01

Full Text Available Objectives: This study was designed to evaluate the analytical performance of the novel Lumipulse G1200 BRAHMS procalcitonin (PCT immunoassay. Design and methods: This analytical evaluation encompassed the calculation of the limit of blank (LOB, limit of detection (LOD, functional sensitivity, intra- and inter-assay imprecision, confirmation of linearity and a comparison with the Vidas BRAHMS PCT assay. Results: The LOB, LOD and functional sensitivity were 0.0010 ng/mL, 0.0016 ng/mL and 0.008 ng/mL, respectively. The total analytical imprecision was found to be 2.1% and the linearity was excellent (r=1.00 in the range of concentrations between 0.006–75.5 ng/mL. The correlation coefficient with Vidas BRAHMS PCT was 0.995 and the equation of the Passing and Bablok regression analysis was [Lumipulse G BRAHMS PCT]=0.76×[Vidas BRAHMS PCT]+0.04. The mean overall bias of Lumipulse G BRAHMS PCT versus Vidas BRAHMS PCT was −3.03 ng/mL (95% confidence interval [CI]: −4.32 to −1.74 ng/mL, whereas the mean bias in samples with PCT concentration between 0–10 ng/mL was −0.49 ng/mL (95% CI: −0.77 to −0.24 ng/mL. The diagnostic agreement was 100% at 0.5 ng/mL, 97% at 2.0 ng/mL and 95% at 10 ng/mL, respectively. Conclusions: These results attest that Lumipulse G BRAHMS PCT exhibits excellent analytical performance, among the best of the methods currently available on the diagnostic market. However, the significant bias compared to the Vidas BRAHMS PCT suggests that the methods cannot be used interchangeably. Keywords: Sepsis, Infection, Procalcitonin, Immunoassay

Point-of-care estimation of haemoglobin concentration in neonates ...

African Journals Online (AJOL)

Objective. The HemoCue is a point-of-care analytical system for haemoglobin concentration (Hb) measurement. Point-of-care testing has been validated in hospitals and outpatient departments to assist with urgent patient management by providing rapid laboratory test results. Method. In this prospective study we compared ...

Biological variation and analytical imprecision of CA 125 in patients with ovarian cancer

DEFF Research Database (Denmark)

Tuxen, M K; Sölétormos, G; Rustin, G J

2000-01-01

Despite the availability of serial data on CA 125 in ovarian cancer, the problem of interpreting a change over time is still unsolved. Changes in marker concentrations are due not only to patients improving or deteriorating but also to analytical imprecision and normal intra-individual biological...... variation. The aim of this study was to assess the analytical imprecision (CV(A)) and the intra- and inter-individual biological variation (CV(I) and CV(G), respectively) of CA 125 in a group of 26 patients with clinically stable ovarian cancer. Furthermore, the critical difference for a change between two...

Unified theory to evaluate the effect of concentration difference and Peclet number on electroosmotic mobility error of micro electroosmotic flow

KAUST Repository

Wang, Wentao

2012-03-01

Both theoretical analysis and nonlinear 2D numerical simulations are used to study the concentration difference and Peclet number effect on the measurement error of electroosmotic mobility in microchannels. We propose a compact analytical model for this error as a function of normalized concentration difference and Peclet number in micro electroosmotic flow. The analytical predictions of the errors are consistent with the numerical simulations. © 2012 IEEE.

Validation of an analytical methodology for the quantitative analysis of petroleum hydrocarbons in marine sediment samples

Directory of Open Access Journals (Sweden)

Eloy Yordad Companioni Damas

2009-01-01

Full Text Available This work describes a validation of an analytical procedure for the analysis of petroleum hydrocarbons in marine sediment samples. The proposed protocol is able to measure n-alkanes and polycyclic aromatic hydrocarbons (PAH in samples at concentrations as low as 30 ng/g, with a precision better than 15% for most of analytes. The extraction efficiency of fortified sediments varied from 65.1 to 105.6% and 59.7 to 97.8%, for n-alkanes and PAH in the ranges: C16 - C32 and fluoranthene - benzo(apyrene, respectively. The analytical protocol was applied to determine petroleum hydrocarbons in sediments collected from a marine coastal zone.

Photorefractive keratectomy: measuring the matrix metalloproteinase activity and chondroitin sulfate concentration in tear fluid

Directory of Open Access Journals (Sweden)

Tetsuya Mutoh

2010-09-01

Full Text Available Tetsuya Mutoh, Masaya Nishio, Yukihiro Matsumoto, Kiyomi Arai, Makoto ChikudaDepartment of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Saitama, JapanAbstract: We herein report the case of a 20-year-old man who underwent a photorefractive keratectomy (PRK. We measured matrix metalloproteinase-9 (MMP-9 activity and chondroitin 4 sulfate and chondroitin 6 sulfate concentrations in tear fluid. Tear fluid was collected preoperatively via microcapillary tube, and was collected postoperatively on the first and fourth days, and after one week, one month, three months, and six months. Samples were formulated by dilution with 200 µL of saline. MMP-9 activity was analyzed by an enzyme immunocapture activity assay, and the concentrations of chondroitin sulfate were analyzed by enzyme-linked immunosorbent assay. No complications were observed after surgery, except for a minimal subepithelial haze. Although MMP-9 activity changed on the fourth postoperative day, the activity changed only minimally at this time. Chondroitin 4 sulfate concentrations in tear fluid increased dramatically from one week to one month, decreased transiently at three months, and increased by six months. The chondroitin 6 sulfate concentration did not normalize within one week, and decreased from one week to three months compared with the preoperative score, and was close to the preoperative score at six months. We conclude that corneal wound healing was still incomplete six months after PRK, and chondroitin 4 sulfate appears to be critical in this process.Keywords: matrix metalloproteinase, chondroitin sulfate, human tear fluid, photorefractive keratectomy, corneal wound healing

Characterization of dilation-analytic operators

Energy Technology Data Exchange (ETDEWEB)

Balslev, E; Grossmann, A; Paul, T

1986-01-01

Dilation analytic vectors and operators are characterized in a new representation of quantum mechanical states through functions analytic on the upper half-plane. In this space H/sub o/-bounded operators are integral operators and criteria for dilation analyticity are given in terms of analytic continuation outside of the half-plane for functions and for kernels. A sufficient condition is given for an integral operator in momentum space to be dilation-analytic.

Proceedings of the DAE-BRNS theme meeting on recent trends in analytical chemistry: book of abstracts

International Nuclear Information System (INIS)

2012-01-01

Analytical chemistry is the branch of science that deals with the determination of the identity and concentration of various elements and compounds in different matrices including living systems. The practice of analytical chemistry as a distinct discipline possibly began in the late eighteenth century with the work of the French chemist Antoine-Laurent Lavoisier and his contemporaries. Further progress was made in the nineteenth century by scientists like Carl Fresenius and Karl Friedrich Mohr. Fresenius developed the qualitative analysis method and it formed the topic of the first textbook of analytical chemistry. He also developed the gravimetric technique. Mohr developed many laboratory analytical procedures and devices. Most of the major advances in analytical chemistry, as in many other branches of science, took place in the twentieth century after the Second World War. The demand for new and increasingly sophisticated analytical techniques for bio-medical, regulatory and strategic requirements, along with the progress in electro-mechanical instrumentation, automation and computerization, has opened up new challenges and opportunities for analytical chemists and allied scientists in the years to come. Papers relevant to INIS are indexed separately

The preparation and certification of a South African phosphate concentrate for use as a reference material

International Nuclear Information System (INIS)

Hansen, R.G.

1985-01-01

This report describes the preparation, analysis, and certification of South African Reference Material (SARM) 32. The material is a phosphate concentrate from the Phalaborwa deposit, and was supplied by the Phosphate Development Corporation Ltd (Foskor). Eighteen laboratories in eight countries used a variety of analytical techniques to provide the analytical results

A new tool for the evaluation of the analytical procedure: Green Analytical Procedure Index.

Science.gov (United States)

Płotka-Wasylka, J

2018-05-01

A new means for assessing analytical protocols relating to green analytical chemistry attributes has been developed. The new tool, called GAPI (Green Analytical Procedure Index), evaluates the green character of an entire analytical methodology, from sample collection to final determination, and was created using such tools as the National Environmental Methods Index (NEMI) or Analytical Eco-Scale to provide not only general but also qualitative information. In GAPI, a specific symbol with five pentagrams can be used to evaluate and quantify the environmental impact involved in each step of an analytical methodology, mainly from green through yellow to red depicting low, medium to high impact, respectively. The proposed tool was used to evaluate analytical procedures applied in the determination of biogenic amines in wine samples, and polycyclic aromatic hydrocarbon determination by EPA methods. GAPI tool not only provides an immediately perceptible perspective to the user/reader but also offers exhaustive information on evaluated procedures. Copyright © 2018 Elsevier B.V. All rights reserved.

Experimental characterization of a concentrating photovoltaic system varying the light concentration

International Nuclear Information System (INIS)

Renno, C.; Petito, F.; Landi, G.; Neitzert, H.C.

2017-01-01

Highlights: • Experimental characterization of a concentrating photovoltaic system. • Analysis of the point-focus concentrating system performances. • Photovoltaic system parameters as function of the concentration factor. - Abstract: The concentrating photovoltaic system represents one of the most promising solar technologies because it allows a more efficient energy conversion. When a CPV system is designed, the main parameter which has to be considered is the concentration factor that affects both the system energy performances and its configuration. An experimental characterization of a CPV system previously realized at the University of Salerno, is presented in this paper considering several aspects related to the optical configuration, the concentration factor and the solar cell used. In particular, the parameters of an Indium Gallium Phosphide/Gallium Arsenide/Germanium triple-junction solar cell are investigated as function of the concentration factor determined by means of an experimental procedure that uses different optical configurations. The maximum concentration factor reached by the CPV system is 310 suns. The cell parameters dependence on the concentration is reported together with an electroluminescence analysis of the Indium Gallium Phosphide/Gallium Arsenide/Germanium cell. A monitoring of the electrical power provided by the system during its working is also presented corresponding to different direct irradiance values. A mean power of 2.95 W with an average efficiency of 32.8% is obtained referring to a mean irradiance of 930 W/m"2; lower values are obtained when the irradiance is highly fluctuating. The concentrating photovoltaic system electric energy output is estimated considering different concentration levels; the maximal obtained value is 23.5 W h on a sunny day at 310×. Finally, the temperature of the triple-junction solar cell is evaluated for different months in order to evaluate the potential annual thermal energy production

Google analytics integrations

CERN Document Server

Waisberg, Daniel

2015-01-01

A roadmap for turning Google Analytics into a centralized marketing analysis platform With Google Analytics Integrations, expert author Daniel Waisberg shows you how to gain a more meaningful, complete view of customers that can drive growth opportunities. This in-depth guide shows not only how to use Google Analytics, but also how to turn this powerful data collection and analysis tool into a central marketing analysis platform for your company. Taking a hands-on approach, this resource explores the integration and analysis of a host of common data sources, including Google AdWords, AdSens

Energy content of hybrid Rumex patienta L. x Rumex tianschanicus A. Los. (Rumex OK 2 samples from autumn months

Directory of Open Access Journals (Sweden)

Michal Rolinec

2018-03-01

Full Text Available Aim of this experiment was to determine the gross energy concentration of fresh, wilted and ensiled hybrid of Rumex patientia L. x Rumex tianschanicus A. Los. (Rumex OK 2. Samples were collected in autumn months of the year 2017. The plant of Rumex OK 2 consist during autumn months only from rosette of leaves. The height of leaves was in autumn months following, September 56.68±13.80 cm; October 59.29±11.93 cm and November 55.98±10.80 cm. Rumex OK 2 silage was made from wilted matter, with or without of addition of dried molasses. Gross energy was determined as the heat released after combustion of a sample (Leco AC 500 in MJ per kilogram of dry matter of the sample. By the autumn months the concentration of dry matter, as well as the concentration of gross energy increased, except Rumex OK 2 silage from November. The highest concentration of gross energy had wilted Rumex OK 2 from November (18.02 MJ.kg-1 of dry matter. There was no significant effect of addition of dried molasses to wilted Rumex OK 2 before ensiling on gross energy concentration in Rumex OK 2 silages (P>0.05. Gross energy concentration of all types of analysed samples had relative high value (16.98 to 18.02 MJ.kg-1 of dry matter. Fresh or ensiled Rumex OK 2 can be used as a part of feed ratio for ruminants or can be utilised in biogas station. However, due to the low content of dry mater in fresh or wilted material the production of silage can be in autumn months problematic.

A cohort study of developmental polychlorinated biphenyl (PCB) exposure in relation to post-vaccination antibody response at 6-months of age

International Nuclear Information System (INIS)

Jusko, Todd A.; De Roos, Anneclaire J.; Schwartz, Stephen M.; Paige Lawrence, B.; Palkovicova, Lubica; Nemessanyi, Tomas; Drobna, Beata; Fabisikova, Anna; Kocan, Anton; Sonneborn, Dean; Jahnova, Eva; Kavanagh, Terrance J.; Trnovec, Tomas; Hertz-Picciotto, Irva

2010-01-01

Background: Extensive experimental data in animals indicate that exposure to polychlorinated biphenyls (PCBs) during pregnancy leads to changes in offspring immune function during the postnatal period. Whether developmental PCB exposure influences immunologic development in humans has received little study. Methods: The study population was 384 mother-infant pairs recruited from two districts of eastern Slovakia for whom prospectively collected maternal, cord, and 6-month infant blood specimens were available. Several PCB congeners were measured in maternal, cord, and 6-month infant sera by high-resolution gas chromatography with electron capture detection. Concentrations of IgG-specific anti-haemophilus influenzae type b, tetanus toxoid, and diphtheria toxoid were assayed in 6-month infant sera using ELISA methods. Multiple linear regression was used to estimate the relation between maternal, cord, and 6-month infant PCB concentrations and the antibody concentrations evaluated at 6-months of age. Results: Overall, there was little evidence of an association between infant antibody concentrations and PCB measures during the pre- and early postnatal period. In addition, our results did not show specificity in terms of associations limited to a particular developmental period (e.g. pre- vs. postnatal), a particular antibody, or a particular PCB congener. Conclusions: At the PCB concentrations measured in this cohort, which are high relative to most human populations today, we did not detect an association between maternal or early postnatal PCB exposure and specific antibody responses at 6-months of age.

A cohort study of developmental polychlorinated biphenyl (PCB) exposure in relation to post-vaccination antibody response at 6-months of age

Energy Technology Data Exchange (ETDEWEB)

Jusko, Todd A., E-mail: juskota@niehs.nih.gov [Epidemiology Branch, National Institute of Environmental Health Sciences, PO Box 12233, MD A3-05, 111 T.W. Alexander Dr, Rall Bldg 101, Rm A361, Research Triangle Park, NC 27709-2233 (United States); Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA (United States); De Roos, Anneclaire J.; Schwartz, Stephen M. [Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA (United States); Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA (United States); Paige Lawrence, B. [Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY (United States); Palkovicova, Lubica [Department of Environmental Medicine, Slovak Medical University, Bratislava (Slovakia); Nemessanyi, Tomas [Department of Immunology and Immunotoxicology, Slovak Medical University, Bratislava (Slovakia); Drobna, Beata; Fabisikova, Anna; Kocan, Anton [Department of Toxic Organic Pollutants, Slovak Medical University, Bratislava (Slovakia); Sonneborn, Dean [Department of Public Health Sciences, University of California, Davis, CA (United States); Jahnova, Eva [Department of Immunology and Immunotoxicology, Slovak Medical University, Bratislava (Slovakia); Kavanagh, Terrance J. [Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA (United States); Trnovec, Tomas [Department of Toxic Organic Pollutants, Slovak Medical University, Bratislava (Slovakia); Hertz-Picciotto, Irva [Department of Public Health Sciences, University of California, Davis, CA (United States)

2010-05-15

Background: Extensive experimental data in animals indicate that exposure to polychlorinated biphenyls (PCBs) during pregnancy leads to changes in offspring immune function during the postnatal period. Whether developmental PCB exposure influences immunologic development in humans has received little study. Methods: The study population was 384 mother-infant pairs recruited from two districts of eastern Slovakia for whom prospectively collected maternal, cord, and 6-month infant blood specimens were available. Several PCB congeners were measured in maternal, cord, and 6-month infant sera by high-resolution gas chromatography with electron capture detection. Concentrations of IgG-specific anti-haemophilus influenzae type b, tetanus toxoid, and diphtheria toxoid were assayed in 6-month infant sera using ELISA methods. Multiple linear regression was used to estimate the relation between maternal, cord, and 6-month infant PCB concentrations and the antibody concentrations evaluated at 6-months of age. Results: Overall, there was little evidence of an association between infant antibody concentrations and PCB measures during the pre- and early postnatal period. In addition, our results did not show specificity in terms of associations limited to a particular developmental period (e.g. pre- vs. postnatal), a particular antibody, or a particular PCB congener. Conclusions: At the PCB concentrations measured in this cohort, which are high relative to most human populations today, we did not detect an association between maternal or early postnatal PCB exposure and specific antibody responses at 6-months of age.

Design and simulation of a low concentrating photovoltaic/thermal system

International Nuclear Information System (INIS)

Rosell, J.I.; Vallverdu, X.; Lechon, M.A.; Ibanez, M.

2005-01-01

The advantages of photovoltaic/thermal (PV/T) collectors and low solar concentration technologies are combined into a photovoltaic/thermal system to increase the solar energy conversion efficiency. This paper presents a prototype 11X concentration rate and two axis tracking system. The main novelty is the coupling of a linear Fresnel concentrator with a channel photovoltaic/thermal collector. An analytical model to simulate the thermal behaviour of the prototype is proposed and validated. Measured thermal performance of the solar system gives values above 60%. Theoretical analysis confirms that thermal conduction between the PV cells and the absorber plate is a critical parameter

SRL online Analytical Development

International Nuclear Information System (INIS)

Jenkins, C.W.

1991-01-01

The Savannah River Site is operated by the Westinghouse Savannah River Co. for the Department of Energy to produce special nuclear materials for defense. R ampersand D support for site programs is provided by the Savannah River Laboratory, which I represent. The site is known primarily for its nuclear reactors, but actually three fourths of the efforts at the site are devoted to fuel/target fabrication, fuel/target reprocessing, and waste management. All of these operations rely heavily on chemical processes. The site is therefore a large chemical plant. There are then many potential applications for process analytical chemistry at SRS. The Savannah River Laboratory (SRL) has an Analytical Development Section of roughly 65 personnel that perform analyses for R ampersand D efforts at the lab, act as backup to the site Analytical Laboratories Department and develop analytical methods and instruments. I manage a subgroup of the Analytical Development Section called the Process Control ampersand Analyzer Development Group. The Prime mission of this group is to develop online/at-line analytical systems for site applications

Analytical mechanics

CERN Document Server

Lemos, Nivaldo A

2018-01-01

Analytical mechanics is the foundation of many areas of theoretical physics including quantum theory and statistical mechanics, and has wide-ranging applications in engineering and celestial mechanics. This introduction to the basic principles and methods of analytical mechanics covers Lagrangian and Hamiltonian dynamics, rigid bodies, small oscillations, canonical transformations and Hamilton–Jacobi theory. This fully up-to-date textbook includes detailed mathematical appendices and addresses a number of advanced topics, some of them of a geometric or topological character. These include Bertrand's theorem, proof that action is least, spontaneous symmetry breakdown, constrained Hamiltonian systems, non-integrability criteria, KAM theory, classical field theory, Lyapunov functions, geometric phases and Poisson manifolds. Providing worked examples, end-of-chapter problems, and discussion of ongoing research in the field, it is suitable for advanced undergraduate students and graduate students studying analyt...

Contaminant ingress into multizone buildings: An analytical state-space approach

KAUST Repository

Parker, Simon

2013-08-13

The ingress of exterior contaminants into buildings is often assessed by treating the building interior as a single well-mixed space. Multizone modelling provides an alternative way of representing buildings that can estimate concentration time series in different internal locations. A state-space approach is adopted to represent the concentration dynamics within multizone buildings. Analysis based on this approach is used to demonstrate that the exposure in every interior location is limited to the exterior exposure in the absence of removal mechanisms. Estimates are also developed for the short term maximum concentration and exposure in a multizone building in response to a step-change in concentration. These have considerable potential for practical use. The analytical development is demonstrated using a simple two-zone building with an inner zone and a range of existing multizone models of residential buildings. Quantitative measures are provided of the standard deviation of concentration and exposure within a range of residential multizone buildings. Ratios of the maximum short term concentrations and exposures to single zone building estimates are also provided for the same buildings. © 2013 Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

Analytic solution for one-dimensional diffusion of radionuclides from a waste package

International Nuclear Information System (INIS)

Oliver, D.L.

1985-01-01

This work implements an analytical solution for diffusion of radionuclides from a cylindrical waste form through the packing material into the surrounding host rock. Recent interest in predicting the performance of a proposed geological repository for nuclear waste has led to the development of several computer programs to predict the performance of such a repository for the next several millenia. These numerical codes are generally designed to accommodate a broad spectrum of geometrical configurations and repository conditions in order to accurately predict the behavior of the radionuclides in the repository environment. Confidence in such general purpose codes is gained by verifying the numerical modeling and the software through comparison of the numerical predictions generated by these computer codes with analytical solutions to reasonably complex problems. The analysis discussed herein implements the analytic solution, proposed by J.C. Jaeger in 1941 for radial diffusion through two concentric circular cylinders. Jaeger's solution was applied to the problem of diffusional mass transfer from a long cylindrical waste form and subsequently into the surrounding geological formation. Analytic predictions of fractional release rates, including the effects of sorption, were generated

Analytical interference by contrast agents in biochemical assays

DEFF Research Database (Denmark)

Otnes, Sigrid; Fogh-Andersen, Niels; Rømsing, Janne

2017-01-01

Objective. To provide a clinically relevant overview of the analytical interference by contrast agents (CA) in laboratory blood test measurements. Materials and Methods. The effects of five CAs, gadobutrol, gadoterate meglumine, gadoxetate disodium, iodixanol, and iomeprol, were studied on the 29...... most frequently performed biochemical assays. One-day-old plasma, serum, and whole blood were spiked with doses of each agent such that the gadolinium agents and the iodine agents reached concentrations of 0.5mMand 12mg iodine/mL, respectively. Subsequently, 12 assays were reexamined using 1/2 and 1...

Importance of implementing an analytical quality control system in a core laboratory.

Science.gov (United States)

Marques-Garcia, F; Garcia-Codesal, M F; Caro-Narros, M R; Contreras-SanFeliciano, T

2015-01-01

The aim of the clinical laboratory is to provide useful information for screening, diagnosis and monitoring of disease. The laboratory should ensure the quality of extra-analytical and analytical process, based on set criteria. To do this, it develops and implements a system of internal quality control, designed to detect errors, and compare its data with other laboratories, through external quality control. In this way it has a tool to detect the fulfillment of the objectives set, and in case of errors, allowing corrective actions to be made, and ensure the reliability of the results. This article sets out to describe the design and implementation of an internal quality control protocol, as well as its periodical assessment intervals (6 months) to determine compliance with pre-determined specifications (Stockholm Consensus(1)). A total of 40 biochemical and 15 immunochemical methods were evaluated using three different control materials. Next, a standard operation procedure was planned to develop a system of internal quality control that included calculating the error of the analytical process, setting quality specifications, and verifying compliance. The quality control data were then statistically depicted as means, standard deviations, and coefficients of variation, as well as systematic, random, and total errors. The quality specifications were then fixed and the operational rules to apply in the analytical process were calculated. Finally, our data were compared with those of other laboratories through an external quality assurance program. The development of an analytical quality control system is a highly structured process. This should be designed to detect errors that compromise the stability of the analytical process. The laboratory should review its quality indicators, systematic, random and total error at regular intervals, in order to ensure that they are meeting pre-determined specifications, and if not, apply the appropriate corrective actions

Ratio-based vs. model-based methods to correct for urinary creatinine concentrations.

Science.gov (United States)

Jain, Ram B

2016-08-01

Creatinine-corrected urinary analyte concentration is usually computed as the ratio of the observed level of analyte concentration divided by the observed level of the urinary creatinine concentration (UCR). This ratio-based method is flawed since it implicitly assumes that hydration is the only factor that affects urinary creatinine concentrations. On the contrary, it has been shown in the literature, that age, gender, race/ethnicity, and other factors also affect UCR. Consequently, an optimal method to correct for UCR should correct for hydration as well as other factors like age, gender, and race/ethnicity that affect UCR. Model-based creatinine correction in which observed UCRs are used as an independent variable in regression models has been proposed. This study was conducted to evaluate the performance of ratio-based and model-based creatinine correction methods when the effects of gender, age, and race/ethnicity are evaluated one factor at a time for selected urinary analytes and metabolites. It was observed that ratio-based method leads to statistically significant pairwise differences, for example, between males and females or between non-Hispanic whites (NHW) and non-Hispanic blacks (NHB), more often than the model-based method. However, depending upon the analyte of interest, the reverse is also possible. The estimated ratios of geometric means (GM), for example, male to female or NHW to NHB, were also compared for the two methods. When estimated UCRs were higher for the group (for example, males) in the numerator of this ratio, these ratios were higher for the model-based method, for example, male to female ratio of GMs. When estimated UCR were lower for the group (for example, NHW) in the numerator of this ratio, these ratios were higher for the ratio-based method, for example, NHW to NHB ratio of GMs. Model-based method is the method of choice if all factors that affect UCR are to be accounted for.

Analytical chemistry

Energy Technology Data Exchange (ETDEWEB)

Chae, Myeong Hu; Lee, Hu Jun; Kim, Ha Seok

1989-02-15

This book give explanations on analytical chemistry with ten chapters, which deal with development of analytical chemistry, the theory of error with definition and classification, sample and treatment gravimetry on general process of gravimetry in aqueous solution and non-aqueous solution, precipitation titration about precipitation reaction and types, complexometry with summary and complex compound, oxidation-reduction equilibrium on electrode potential and potentiometric titration, solvent extraction and chromatograph and experiment with basic operation for chemical experiment.

Analytical chemistry

International Nuclear Information System (INIS)

Chae, Myeong Hu; Lee, Hu Jun; Kim, Ha Seok

1989-02-01

This book give explanations on analytical chemistry with ten chapters, which deal with development of analytical chemistry, the theory of error with definition and classification, sample and treatment gravimetry on general process of gravimetry in aqueous solution and non-aqueous solution, precipitation titration about precipitation reaction and types, complexometry with summary and complex compound, oxidation-reduction equilibrium on electrode potential and potentiometric titration, solvent extraction and chromatograph and experiment with basic operation for chemical experiment.

Analytical procedures for determining Pb and Sr isotopic compositions in water samples by ID-TIMS

Directory of Open Access Journals (Sweden)

Veridiana Martins

2008-01-01

Full Text Available Few articles deal with lead and strontium isotopic analysis of water samples. The aim of this study was to define the chemical procedures for Pb and Sr isotopic analyses of groundwater samples from an urban sedimentary aquifer. Thirty lead and fourteen strontium isotopic analyses were performed to test different analytical procedures. Pb and Sr isotopic ratios as well as Sr concentration did not vary using different chemical procedures. However, the Pb concentrations were very dependent on the different procedures. Therefore, the choice of the best analytical procedure was based on the Pb results, which indicated a higher reproducibility from samples that had been filtered and acidified before the evaporation, had their residues totally dissolved, and were purified by ion chromatography using the Biorad® column. Our results showed no changes in Pb ratios with the storage time.

Estimating absorption coefficients of colored dissolved organic matter (CDOM) using a semi-analytical algorithm for southern Beaufort Sea waters: application to deriving concentrations of dissolved organic carbon from space

Science.gov (United States)

Matsuoka, A.; Hooker, S. B.; Bricaud, A.; Gentili, B.; Babin, M.

2013-02-01

A series of papers have suggested that freshwater discharge, including a large amount of dissolved organic matter (DOM), has increased since the middle of the 20th century. In this study, a semi-analytical algorithm for estimating light absorption coefficients of the colored fraction of DOM (CDOM) was developed for southern Beaufort Sea waters using remote sensing reflectance at six wavelengths in the visible spectral domain corresponding to MODIS ocean color sensor. This algorithm allows the separation of colored detrital matter (CDM) into CDOM and non-algal particles (NAP) through the determination of NAP absorption using an empirical relationship between NAP absorption and particle backscattering coefficients. Evaluation using independent datasets, which were not used for developing the algorithm, showed that CDOM absorption can be estimated accurately to within an uncertainty of 35% and 50% for oceanic and coastal waters, respectively. A previous paper (Matsuoka et al., 2012) showed that dissolved organic carbon (DOC) concentrations were tightly correlated with CDOM absorption in our study area (r2 = 0.97). By combining the CDOM absorption algorithm together with the DOC versus CDOM relationship, it is now possible to estimate DOC concentrations in the near-surface layer of the southern Beaufort Sea using satellite ocean color data. DOC concentrations in the surface waters were estimated using MODIS ocean color data, and the estimates showed reasonable values compared to in situ measurements. We propose a routine and near real-time method for deriving DOC concentrations from space, which may open the way to an estimate of DOC budgets for Arctic coastal waters.

Analytical method for the isotopic characterization of soils

International Nuclear Information System (INIS)

Sibello Hernandez, Rita; Cozzella, Maria Letizia; Mariani, Mario

2014-01-01

The aim of this work was to develop an analytical method in order to determine the isotopic composition of different elements in soil samples and to determine the existence of contamination. The method used in the digestion of the samples was the EPA 3050B, and some metal concentration were determined including uranium and thorium. For elements with even lower concentrations such as plutonium and radium a treatment after mineralization by EPA, was necessary. The measurement technique used was mass spectrometry with quadrupole and plasma induced associated (ICP-MS). Results of the analysis performed in two laboratories showed a good correspondence. This method allowed to perform the isotopic characterization of studied soils and results showed that the studied soils do not present any local pollution and that the presence of plutonium-239, is due to global failure

Monthly oral methylprednisolone pulse treatment in progressive multiple sclerosis.

Science.gov (United States)

Ratzer, Rikke; Iversen, Pernille; Börnsen, Lars; Dyrby, Tim B; Romme Christensen, Jeppe; Ammitzbøll, Cecilie; Madsen, Camilla Gøbel; Garde, Ellen; Lyksborg, Mark; Andersen, Birgit; Hyldstrup, Lars; Sørensen, Per Soelberg; Siebner, Hartwig R; Sellebjerg, Finn

2016-06-01

There is a large unmet need for treatments for patients with progressive multiple sclerosis (MS). Phase 2 studies with cerebrospinal fluid (CSF) biomarker outcomes may be well suited for the initial evaluation of efficacious treatments. To evaluate the effect of monthly oral methylprednisolone pulse treatment on intrathecal inflammation in progressive MS. In this open-label phase 2A study, 15 primary progressive and 15 secondary progressive MS patients received oral methylprednisolone pulse treatment for 60 weeks. Primary outcome was changes in CSF concentrations of osteopontin. Secondary outcomes were other CSF biomarkers of inflammation, axonal damage and demyelination; clinical scores; magnetic resonance imaging measures of disease activity, magnetization transfer ratio (MTR) and diffusion tensor imaging (DTI); motor evoked potentials; and bone density scans. We found no change in the CSF concentration of osteopontin, but we observed significant improvement in clinical scores, MTR, DTI and some secondary CSF outcome measures. Adverse events were well-known side effects to methylprednisolone. Monthly methylprednisolone pulse treatment was safe, but had no effect on the primary outcome. However, improvements in secondary clinical and MRI outcome measures suggest that this treatment regimen may have a beneficial effect in progressive MS. © The Author(s), 2015.

Concentrations of Se, Ba, Zn and Mn in Brazil nuts

Energy Technology Data Exchange (ETDEWEB)

Armelin, Maria José A.; Maihara, Vera A.; Cardoso, Paulo S.; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Cozollino, Silvia M.F., E-mail: marmelin@ipen.br, E-mail: vmaihara@ipen.br, E-mail: msaiki@ipen.br, E-mail: pscsilva@ipen.br, E-mail: smfcozzo@usp.br [Universidade de São Paulo (USP), SP (Brazil). Faculdade de Ciências Farmacêuticas

2017-07-01

The concentrations of Se, Ba, Zn and Mn were determined in samples of Brazil nuts collected in two ways: a) in a production farm predominantly for export and, b) in various points of sale from different regions of Brazil. Instrumental neutron activation analysis was the analytical technique used in this study. Results indicate that the concentrations of Se and Ba varied greatly among the Brazil nut samples analyzed. This large variability may be related to the soil characteristics from which the nuts were produced. An inverse correlation was observed between the concentrations of Se and Ba. On the other hand, the concentrations of Zn and Mn did not show significant differences among these samples. (author)

Concentrations of Se, Ba, Zn and Mn in Brazil nuts

International Nuclear Information System (INIS)

Armelin, Maria José A.; Maihara, Vera A.; Cardoso, Paulo S.; Saiki, Mitiko; Cozollino, Silvia M.F.

2017-01-01

The concentrations of Se, Ba, Zn and Mn were determined in samples of Brazil nuts collected in two ways: a) in a production farm predominantly for export and, b) in various points of sale from different regions of Brazil. Instrumental neutron activation analysis was the analytical technique used in this study. Results indicate that the concentrations of Se and Ba varied greatly among the Brazil nut samples analyzed. This large variability may be related to the soil characteristics from which the nuts were produced. An inverse correlation was observed between the concentrations of Se and Ba. On the other hand, the concentrations of Zn and Mn did not show significant differences among these samples. (author)

Heavy metal phytoremediation from a meta-analytical perspective

Energy Technology Data Exchange (ETDEWEB)

Audet, Patrick [Ottawa-Carleton Institute of Biology, Department of Biology, University of Ottawa, 30 Marie-Curie St., Ottawa, Ont. K1N 6N5 (Canada)]. E-mail: paude086@uottawa.ca; Charest, Christiane [Ottawa-Carleton Institute of Biology, Department of Biology, University of Ottawa, 30 Marie-Curie St., Ottawa, Ont. K1N 6N5 (Canada)]. E-mail: ccharest@science.uottawa.ca

2007-05-15

We conducted a literature survey and correlated heavy metal (HM) uptake and plant growth factors from published data to estimate the effectiveness of phytoextraction. The indicators of the actual plant HM uptake showed positive correlations with soil-HM concentrations, while the relative plant HM uptake showed negative correlations. Plant growth was negatively correlated with both the plant and soil-HM concentrations. These significant relationships were found for the majority of HM tested (e.g. Zn, Cd, Pb, Cu, Cr, and Fe) with a few exceptions (e.g. Ni, Co, and Mn). After fitting the correlation coefficients, the highest proportion of variance among the studies was mainly due to the experimental parameters or the plant species. When the metabolic costs of HM uptake are taken into account, the phytoextraction appears to be less effective beyond critical HM concentrations. Despite these constraints, it is emphasized that HM phytoextraction can play an important role in bioremediation. - This meta-analytical approach has revealed a compromise between growth and HM uptake when plants are subjected to toxic soil-HM levels.

Heavy metal phytoremediation from a meta-analytical perspective

International Nuclear Information System (INIS)

Audet, Patrick; Charest, Christiane

2007-01-01

We conducted a literature survey and correlated heavy metal (HM) uptake and plant growth factors from published data to estimate the effectiveness of phytoextraction. The indicators of the actual plant HM uptake showed positive correlations with soil-HM concentrations, while the relative plant HM uptake showed negative correlations. Plant growth was negatively correlated with both the plant and soil-HM concentrations. These significant relationships were found for the majority of HM tested (e.g. Zn, Cd, Pb, Cu, Cr, and Fe) with a few exceptions (e.g. Ni, Co, and Mn). After fitting the correlation coefficients, the highest proportion of variance among the studies was mainly due to the experimental parameters or the plant species. When the metabolic costs of HM uptake are taken into account, the phytoextraction appears to be less effective beyond critical HM concentrations. Despite these constraints, it is emphasized that HM phytoextraction can play an important role in bioremediation. - This meta-analytical approach has revealed a compromise between growth and HM uptake when plants are subjected to toxic soil-HM levels

Second International Workshop on Teaching Analytics

DEFF Research Database (Denmark)

Vatrapu, Ravi; Reimann, Peter; Halb, Wolfgang

2013-01-01

Teaching Analytics is conceived as a subfield of learning analytics that focuses on the design, development, evaluation, and education of visual analytics methods and tools for teachers in primary, secondary, and tertiary educational settings. The Second International Workshop on Teaching Analytics...... (IWTA) 2013 seeks to bring together researchers and practitioners in the fields of education, learning sciences, learning analytics, and visual analytics to investigate the design, development, use, evaluation, and impact of visual analytical methods and tools for teachers’ dynamic diagnostic decision...

Feedback between residual circulations and sediment distribution in highly turbid estuaries: an analytical model

NARCIS (Netherlands)

Talke, S.A.|info:eu-repo/dai/nl/304823554; de Swart, H.E.|info:eu-repo/dai/nl/073449725; Schuttelaars, H.|info:eu-repo/dai/nl/164035656

2009-01-01

Motivated by field studies of the Ems estuary which show longitudinal gradients in bottom sediment concentration as high as O(0.01 kg/m4), we develop an analytical model for estuarine residual circulation based on currents from salinity gradients, turbidity gradients, and freshwater discharge.

Prevalence of Pre-Analytical Errors in Clinical Chemistry Diagnostic Labs in Sulaimani City of Iraqi Kurdistan.

Science.gov (United States)

Najat, Dereen

2017-01-01

Laboratory testing is roughly divided into three phases: a pre-analytical phase, an analytical phase and a post-analytical phase. Most analytical errors have been attributed to the analytical phase. However, recent studies have shown that up to 70% of analytical errors reflect the pre-analytical phase. The pre-analytical phase comprises all processes from the time a laboratory request is made by a physician until the specimen is analyzed at the lab. Generally, the pre-analytical phase includes patient preparation, specimen transportation, specimen collection and storage. In the present study, we report the first comprehensive assessment of the frequency and types of pre-analytical errors at the Sulaimani diagnostic labs in Iraqi Kurdistan. Over 2 months, 5500 venous blood samples were observed in 10 public diagnostic labs of Sulaimani City. The percentages of rejected samples and types of sample inappropriateness were evaluated. The percentage of each of the following pre-analytical errors were recorded: delay in sample transportation, clotted samples, expired reagents, hemolyzed samples, samples not on ice, incorrect sample identification, insufficient sample, tube broken in centrifuge, request procedure errors, sample mix-ups, communication conflicts, misinterpreted orders, lipemic samples, contaminated samples and missed physician's request orders. The difference between the relative frequencies of errors observed in the hospitals considered was tested using a proportional Z test. In particular, the survey aimed to discover whether analytical errors were recorded and examine the types of platforms used in the selected diagnostic labs. The analysis showed a high prevalence of improper sample handling during the pre-analytical phase. In appropriate samples, the percentage error was as high as 39%. The major reasons for rejection were hemolyzed samples (9%), incorrect sample identification (8%) and clotted samples (6%). Most quality control schemes at Sulaimani

Prevalence of Pre-Analytical Errors in Clinical Chemistry Diagnostic Labs in Sulaimani City of Iraqi Kurdistan.

Directory of Open Access Journals (Sweden)

Dereen Najat

Full Text Available Laboratory testing is roughly divided into three phases: a pre-analytical phase, an analytical phase and a post-analytical phase. Most analytical errors have been attributed to the analytical phase. However, recent studies have shown that up to 70% of analytical errors reflect the pre-analytical phase. The pre-analytical phase comprises all processes from the time a laboratory request is made by a physician until the specimen is analyzed at the lab. Generally, the pre-analytical phase includes patient preparation, specimen transportation, specimen collection and storage. In the present study, we report the first comprehensive assessment of the frequency and types of pre-analytical errors at the Sulaimani diagnostic labs in Iraqi Kurdistan.Over 2 months, 5500 venous blood samples were observed in 10 public diagnostic labs of Sulaimani City. The percentages of rejected samples and types of sample inappropriateness were evaluated. The percentage of each of the following pre-analytical errors were recorded: delay in sample transportation, clotted samples, expired reagents, hemolyzed samples, samples not on ice, incorrect sample identification, insufficient sample, tube broken in centrifuge, request procedure errors, sample mix-ups, communication conflicts, misinterpreted orders, lipemic samples, contaminated samples and missed physician's request orders. The difference between the relative frequencies of errors observed in the hospitals considered was tested using a proportional Z test. In particular, the survey aimed to discover whether analytical errors were recorded and examine the types of platforms used in the selected diagnostic labs.The analysis showed a high prevalence of improper sample handling during the pre-analytical phase. In appropriate samples, the percentage error was as high as 39%. The major reasons for rejection were hemolyzed samples (9%, incorrect sample identification (8% and clotted samples (6%. Most quality control schemes

BLOOD SELENIUM CONCENTRATION AFFECT MASTITIS AND MILK QUALITY IN DAIRY COWS

Directory of Open Access Journals (Sweden)

Davidov Ivana

2013-02-01

Full Text Available Milk quality is usually defined in terms of mastitis. Milk with somatic cell count low then 400.000/ml and visibly normal (no clots is considered high quality. Thirty Holstein cows were used in the study to determine affect blood serum selenium concentration on mastitis and milk quality. Cows received ad libitum access to potable water and daily 0.3 mg/kg inorganic selenium supplementation in food. Blood and milk samples were taken at first and sixth lactating month. Mean selenium blood serum concentrations were found to be lower within first lactating month, and then increased in the sixth lactating month. Average somatic cell count at first lactating month was 450.000/ml of milk and at sixth lactating month was 355.000/ml. On the basis of these results it can be conclude that selenium have importance in proper functioning of the mammary glands of cows, and in reducing mastitis and in improving milk quality.

Final Report on the Analytical Results for Tank Farm Samples in Support of Salt Dissolution Evaluation

International Nuclear Information System (INIS)

Hobbs, D.T.

1996-01-01

Recent processing of dilute solutions through the 2H-Evaporator system caused dissolution of salt in Tank 38H, the concentrate receipt tank. This report documents analytical results for samples taken from this evaporator system

Analytical phase diagrams for colloids and non-adsorbing polymer.

Science.gov (United States)

Fleer, Gerard J; Tuinier, Remco

2008-11-04

We review the free-volume theory (FVT) of Lekkerkerker et al. [Europhys. Lett. 20 (1992) 559] for the phase behavior of colloids in the presence of non-adsorbing polymer and we extend this theory in several aspects: (i) We take the solvent into account as a separate component and show that the natural thermodynamic parameter for the polymer properties is the insertion work Pi(v), where Pi is the osmotic pressure of the (external) polymer solution and v the volume of a colloid particle. (ii) Curvature effects are included along the lines of Aarts et al. [J. Phys.: Condens. Matt. 14 (2002) 7551] but we find accurate simple power laws which simplify the mathematical procedure considerably. (iii) We find analytical forms for the first, second, and third derivatives of the grand potential, needed for the calculation of the colloid chemical potential, the pressure, gas-liquid critical points and the critical endpoint (cep), where the (stable) critical line ends and then coincides with the triple point. This cep determines the boundary condition for a stable liquid. We first apply these modifications to the so-called colloid limit, where the size ratio q(R)=R/a between the radius of gyration R of the polymer and the particle radius a is small. In this limit the binodal polymer concentrations are below overlap: the depletion thickness delta is nearly equal to R, and Pi can be approximated by the ideal (van't Hoff) law Pi=Pi(0)=phi/N, where phi is the polymer volume fraction and N the number of segments per chain. The results are close to those of the original Lekkerkerker theory. However, our analysis enables very simple analytical expressions for the polymer and colloid concentrations in the critical and triple points and along the binodals as a function of q(R). Also the position of the cep is found analytically. In order to make the model applicable to higher size ratio's q(R) (including the so-called protein limit where q(R)>1) further extensions are needed. We

Annual banned-substance review: analytical approaches in human sports drug testing.

Science.gov (United States)

Thevis, Mario; Kuuranne, Tiia; Geyer, Hans; Schänzer, Wilhelm

2017-01-01

There has been an immense amount of visibility of doping issues on the international stage over the past 12 months with the complexity of doping controls reiterated on various occasions. Hence, analytical test methods continuously being updated, expanded, and improved to provide specific, sensitive, and comprehensive test results in line with the World Anti-Doping Agency's (WADA) 2016 Prohibited List represent one of several critical cornerstones of doping controls. This enterprise necessitates expediting the (combined) exploitation of newly generated information on novel and/or superior target analytes for sports drug testing assays, drug elimination profiles, alternative test matrices, and recent advances in instrumental developments. This paper is a continuation of the series of annual banned-substance reviews appraising the literature published between October 2015 and September 2016 concerning human sports drug testing in the context of WADA's 2016 Prohibited List. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Arctic and Southern Ocean Sea Ice Concentrations

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Monthly sea ice concentration for Arctic (1901 to 1995) and Southern oceans (1973 to 1990) were digitized on a standard 1-degree grid (cylindrical projection) to...

Analytical and pre-analytical performance characteristics of a novel cartridge-type blood gas analyzer for point-of-care and laboratory testing.

Science.gov (United States)

Oyaert, Matthijs; Van Maerken, Tom; Bridts, Silke; Van Loon, Silvi; Laverge, Heleen; Stove, Veronique

2018-03-01

Point-of-care blood gas test results may benefit therapeutic decision making by their immediate impact on patient care. We evaluated the (pre-)analytical performance of a novel cartridge-type blood gas analyzer, the GEM Premier 5000 (Werfen), for the determination of pH, partial carbon dioxide pressure (pCO 2 ), partial oxygen pressure (pO 2 ), sodium (Na + ), potassium (K + ), chloride (Cl - ), ionized calcium ( i Ca 2+ ), glucose, lactate, and total hemoglobin (tHb). Total imprecision was estimated according to the CLSI EP5-A2 protocol. The estimated total error was calculated based on the mean of the range claimed by the manufacturer. Based on the CLSI EP9-A2 evaluation protocol, a method comparison with the Siemens RapidPoint 500 and Abbott i-STAT CG8+ was performed. Obtained data were compared against preset quality specifications. Interference of potential pre-analytical confounders on co-oximetry and electrolyte concentrations were studied. The analytical performance was acceptable for all parameters tested. Method comparison demonstrated good agreement to the RapidPoint 500 and i-STAT CG8+, except for some parameters (RapidPoint 500: pCO 2 , K + , lactate and tHb; i-STAT CG8+: pO 2 , Na + , i Ca 2+ and tHb) for which significant differences between analyzers were recorded. No interference of lipemia or methylene blue on CO-oximetry results was found. On the contrary, significant interference for benzalkonium and hemolysis on electrolyte measurements were found, for which the user is notified by an interferent specific flag. Identification of sample errors from pre-analytical sources, such as interferences and automatic corrective actions, along with the analytical performance, ease of use and low maintenance time of the instrument, makes the evaluated instrument a suitable blood gas analyzer for both POCT and laboratory use. Copyright © 2018 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Different Analytical Approaches in Assessing Antibacterial Activity and the Purity of Commercial Lysozyme Preparations for Dairy Application

Directory of Open Access Journals (Sweden)

Luisa Pellegrino

2013-05-01

Full Text Available Hen egg-white lysozyme (LSZ is currently used in the food industry to limit the proliferation of lactic acid bacteria spoilage in the production of wine and beer, and to inhibit butyric acid fermentation in hard and extra hard cheeses (late blowing caused by the outgrowth of clostridial spores. The aim of this work was to evaluate how the enzyme activity in commercial preparations correlates to the enzyme concentration and can be affected by the presence of process-related impurities. Different analytical approaches, including turbidimetric assay, SDS-PAGE and HPLC were used to analyse 17 commercial preparations of LSZ marketed in different countries. The HPLC method adopted by ISO allowed the true LSZ concentration to be determined with accuracy. The turbidimetric assay was the most suitable method to evaluate LSZ activity, whereas SDS-PAGE allowed the presence of other egg proteins, which are potential allergens, to be detected. The analytical results showed that the purity of commercially available enzyme preparations can vary significantly, and evidenced the effectiveness of combining different analytical approaches in this type of control.

Determination of low concentrations of thorium in granites using X-ray fluorescence technique

International Nuclear Information System (INIS)

Shigematsu, H.M.; Sato, I.M.; Iyer, S.S.

1981-03-01

An analytical method for the accurate determination of low concentrations of thorium in rocks using X-ray fluorescence technique, was developed. A tungsten tube was utilized for the production of X-rays. The samples were prepared in the form of double layer pressed pellets using boric acid as a binding agent. The concentration of thorium was determined by measuring the intensity of the characteristic first order Th L α line. The calibration was carried out with USGS rock standards AGV-1, GSP-1 and G-2. Seven granite rocks samples from Granite Mountains of Wyoming, USA, supplied by Dr. Stuckless. Also were analysed. The results obtained were compared with values obtained in others laboratories using different analytical methods. The analyses show that the thorium is concentrated in accessory minerals and presented a non-uniform distribution, making sampling an important factor in the analysis of thorium. A discussion of the precision and accuracy of the method is presented. (Author) [pt

Data Intensive Architecture for Scalable Cyber Analytics

Energy Technology Data Exchange (ETDEWEB)

Olsen, Bryan K.; Johnson, John R.; Critchlow, Terence J.

2011-11-15

events, we utilized multidimensional OLAP data cubes. The data cube structure supports interactive analysis of summary data across multiple dimensions, such as location, time, and protocol. Cube technology also allows the analyst to drill-down into the underlying data set, when events of interest are identified and detailed analysis is required. Unfortunately, when creating these cubes, we ran into significant performance issues with our initial architecture, caused by a combination of the data volume and attribute characteristics. Overcoming, these issues required us to develop a novel, data intensive computing infrastructure. In particular, we ended up combining a Netezza Twin Fin data warehouse appliance, a solid state Fusion IO ioDrive, and the Tableau Desktop business intelligence analytic software. Using this architecture, we were able to analyze a month's worth of flow records comprising 4.9B records, totaling approximately 600GB of data. This paper describes our architecture, the challenges that we encountered, and the work that remains to deploy a fully generalized cyber analytical infrastructure.

Analytic Moufang-transformations

International Nuclear Information System (INIS)

Paal, Eh.N.

1988-01-01

The paper is aimed to be an introduction to the concept of an analytic birepresentation of an analytic Moufang loop. To describe the deviation of (S,T) from associativity, the associators (S,T) are defined and certain constraints for them, called the minimality conditions of (S,T) are established

Measuring myokines with cardiovascular functions: pre-analytical variables affecting the analytical output.

Science.gov (United States)

Lombardi, Giovanni; Sansoni, Veronica; Banfi, Giuseppe

2017-08-01

In the last few years, a growing number of molecules have been associated to an endocrine function of the skeletal muscle. Circulating myokine levels, in turn, have been associated with several pathophysiological conditions including the cardiovascular ones. However, data from different studies are often not completely comparable or even discordant. This would be due, at least in part, to the whole set of situations related to the preparation of the patient prior to blood sampling, blood sampling procedure, processing and/or store. This entire process constitutes the pre-analytical phase. The importance of the pre-analytical phase is often not considered. However, in routine diagnostics, the 70% of the errors are in this phase. Moreover, errors during the pre-analytical phase are carried over in the analytical phase and affects the final output. In research, for example, when samples are collected over a long time and by different laboratories, a standardized procedure for sample collecting and the correct procedure for sample storage are acknowledged. In this review, we discuss the pre-analytical variables potentially affecting the measurement of myokines with cardiovascular functions.

Aptamer- and nucleic acid enzyme-based systems for simultaneous detection of multiple analytes

Science.gov (United States)

Lu, Yi [Champaign, IL; Liu, Juewen [Albuquerque, NM

2011-11-15

The present invention provides aptamer- and nucleic acid enzyme-based systems for simultaneously determining the presence and optionally the concentration of multiple analytes in a sample. Methods of utilizing the system and kits that include the sensor components are also provided. The system includes a first reactive polynucleotide that reacts to a first analyte; a second reactive polynucleotide that reacts to a second analyte; a third polynucleotide; a fourth polynucleotide; a first particle, coupled to the third polynucleotide; a second particle, coupled to the fourth polynucleotide; and at least one quencher, for quenching emissions of the first and second quantum dots, coupled to the first and second reactive polynucleotides. The first particle includes a quantum dot having a first emission wavelength. The second particle includes a second quantum dot having a second emission wavelength different from the first emission wavelength. The third polynucleotide and the fourth polynucleotide are different.

Analytic nuclear scattering theories

International Nuclear Information System (INIS)

Di Marzio, F.; University of Melbourne, Parkville, VIC

1999-01-01

A wide range of nuclear reactions are examined in an analytical version of the usual distorted wave Born approximation. This new approach provides either semi analytic or fully analytic descriptions of the nuclear scattering processes. The resulting computational simplifications, when used within the limits of validity, allow very detailed tests of both nuclear interaction models as well as large basis models of nuclear structure to be performed

Integrated sudomotor axon reflex sweat stimulation for continuous sweat analyte analysis with individuals at rest.

Science.gov (United States)

Sonner, Zachary; Wilder, Eliza; Gaillard, Trudy; Kasting, Gerald; Heikenfeld, Jason

2017-07-25

Eccrine sweat has rapidly emerged as a non-invasive, ergonomic, and rich source of chemical analytes with numerous technological demonstrations now showing the ability for continuous electrochemical sensing. However, beyond active perspirers (athletes, workers, etc.), continuous sweat access in individuals at rest has hindered the advancement of both sweat sensing science and technology. Reported here is integration of sudomotor axon reflex sweat stimulation for continuous wearable sweat analyte analysis, including the ability for side-by-side integration of chemical stimulants & sensors without cross-contamination. This integration approach is uniquely compatible with sensors which consume the analyte (enzymatic) or sensors which equilibrate with analyte concentrations. In vivo validation is performed using iontophoretic delivery of carbachol with ion-selective and impedance sensors for sweat analysis. Carbachol has shown prolonged sweat stimulation in directly stimulated regions for five hours or longer. This work represents a significant leap forward in sweat sensing technology, and may be of broader interest to those interested in on-skin sensing integrated with drug-delivery.

Effect of adjuvant lithium on thyroxine (T4) concentration after radioactive iodine therapy

Energy Technology Data Exchange (ETDEWEB)

Hammond, Emmanuel NiiBoye; Vangu, Mboyo-Di-Tamba Heben Willy [University of the Witwatersrand, Division of Nuclear Medicine and Molecular Imaging, Department of Radiation Sciences, Johannesburg (South Africa)

2016-10-15

To study the effect of adjuvant lithium on serum thyroxine (T4) concentrations in patients treated with radioactive iodine (RAI) therapy in our environment. This was a prospective simple randomized comparative, experimental cohort study of patients with hyperthyroidism referred for RAI ablation therapy in the two main academic hospitals in Johannesburg between February 2014 and September 2015. Amongst the 163 participants in the final analysis, 75 received RAI alone and 88 received RAI with lithium. The difference in mean T4 concentrations at 3 months between the RAI-only group (17.67 pmol/l) and the RAI with lithium group (11.55 pmol/l) was significant with a small effect size (U = 2328.5, Z = -2.700, p = 0.007, r = 0.01). Significant decreases in T4 concentrations were observed as early as 1 month after RAI (p = 0.0001) in the RAI with lithium group, but in the RAI-only group, significant decreases in T4 concentrations were observed only at 3 months after RAI therapy (p = 0.000). Women and patients with Graves' disease who received RAI with adjuvant lithium also showed significant decreases in T4 concentrations at 1 month (p = 0.002 and p = 0.003, respectively). Adjuvant lithium leads to an earlier and better response to RAI therapy with lower T4 concentrations that are achieved earlier. This earlier response and decrease in T4 concentrations were noted in patients with Graves' disease and nodular goitre, and in women with hyperthyroidism who received adjuvant lithium therapy. (orig.)

Concentration of 7Be in the lower atmosphere and fallout rate in Tokai

International Nuclear Information System (INIS)

Amano, Hikaru; Kasai, Atsushi

1981-01-01

Beryllium-7, cosmic ray produced radioactivity, its monthly average concentration in the lower atmosphere and monthly fallout rate were measured in Tokai, Japan. Then, the monthly variations were compared with those of fission products due to nuclear detonations in the atmosphere. The concentration of 7 Be in the lower atmosphere ranged from 0.5 x 10 -1 pCi/m 3 to 2.5 x 10 -1 pCi/m 3 in Tokai between the observed period, 1975 - 1977. The fallout rate of 7 Be vibrated widely, its range was from the detection limits to 1.2 x 10 4 pCi/m 2 . The monthly variations were not always the same with variations of the fission products. Fallout rate of 7 Be depended on the rain strongly. The concentration of 7 Be in the rain was measured, too. Then the range was from 9.2 pCi/l to 1.9 x 10 2 pCi/l between the observed period 1976.9 - 1977.2. (author)

A field study of selected U.S. Geological Survey analytical methods for measuring pesticides in filtered stream water, June - September 2012

Science.gov (United States)

Martin, Jeffrey D.; Norman, Julia E.; Sandstrom, Mark W.; Rose, Claire E.

2017-09-06

U.S. Geological Survey monitoring programs extensively used two analytical methods, gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry, to measure pesticides in filtered water samples during 1992–2012. In October 2012, the monitoring programs began using direct aqueous-injection liquid chromatography tandem mass spectrometry as a new analytical method for pesticides. The change in analytical methods, however, has the potential to inadvertently introduce bias in analysis of datasets that span the change.A field study was designed to document performance of the new method in a variety of stream-water matrices and to quantify any potential changes in measurement bias or variability that could be attributed to changes in analytical methods. The goals of the field study were to (1) summarize performance (bias and variability of pesticide recovery) of the new method in a variety of stream-water matrices; (2) compare performance of the new method in laboratory blank water (laboratory reagent spikes) to that in a variety of stream-water matrices; (3) compare performance (analytical recovery) of the new method to that of the old methods in a variety of stream-water matrices; (4) compare pesticide detections and concentrations measured by the new method to those of the old methods in a variety of stream-water matrices; (5) compare contamination measured by field blank water samples in old and new methods; (6) summarize the variability of pesticide detections and concentrations measured by the new method in field duplicate water samples; and (7) identify matrix characteristics of environmental water samples that adversely influence the performance of the new method. Stream-water samples and a variety of field quality-control samples were collected at 48 sites in the U.S. Geological Survey monitoring networks during June–September 2012. Stream sites were located across the United States and included sites in agricultural and urban land

Age-dependent changes in the total protein concentrations in the ...

African Journals Online (AJOL)

related changes in total protein concentrations in ten regions of the pig brain and hypophyses from birth to 36 months of age. Age-related changes in protein concentrations in all the brain regions except the pons and cerebral cortex were not ...

NITROUS OXIDE CONCENTRATIONS IN SMALL STREAMS OF THE GEORGIA PIEDMONT

Science.gov (United States)

We are measuring the dissolved nitrous oxide concentration in 17 headwater streams in the South Fork Broad River, Georgia watershed on a monthly basis. The selected small streams drain watersheds dominated by forest, pasture, developed, or mixed land uses. Nitrous oxide concentr...

Early gray-matter and white-matter concentration in infancy predict later language skills: a whole brain voxel-based morphometry study.

Science.gov (United States)

Deniz Can, Dilara; Richards, Todd; Kuhl, Patricia K

2013-01-01

Magnetic resonance imaging (MRI) brain scans were obtained from 19 infants at 7 months. Expressive and receptive language performance was assessed at 12 months. Voxel-based morphometry (VBM) identified brain regions where gray-matter and white-matter concentrations at 7 months correlated significantly with children's language scores at 12 months. Early gray-matter concentration in the right cerebellum, early white-matter concentration in the right cerebellum, and early white-matter concentration in the left posterior limb of the internal capsule (PLIC)/cerebral peduncle were positively and strongly associated with infants' receptive language ability at 12 months. Early gray-matter concentration in the right hippocampus was positively and strongly correlated with infants' expressive language ability at 12 months. Our results suggest that the cerebellum, PLIC/cerebral peduncle, and the hippocampus may be associated with early language development. Potential links between these structural predictors and infants' linguistic functions are discussed. Copyright © 2012 Elsevier Inc. All rights reserved.

Quo vadis, analytical chemistry?

Science.gov (United States)

Valcárcel, Miguel

2016-01-01

This paper presents an open, personal, fresh approach to the future of Analytical Chemistry in the context of the deep changes Science and Technology are anticipated to experience. Its main aim is to challenge young analytical chemists because the future of our scientific discipline is in their hands. A description of not completely accurate overall conceptions of our discipline, both past and present, to be avoided is followed by a flexible, integral definition of Analytical Chemistry and its cornerstones (viz., aims and objectives, quality trade-offs, the third basic analytical reference, the information hierarchy, social responsibility, independent research, transfer of knowledge and technology, interfaces to other scientific-technical disciplines, and well-oriented education). Obsolete paradigms, and more accurate general and specific that can be expected to provide the framework for our discipline in the coming years are described. Finally, the three possible responses of analytical chemists to the proposed changes in our discipline are discussed.

Study of Maternal Knowledge and Attitude toward Exclusive Breast Milk Feeding (BMF in the First 6 Months of Infant in Yazd-Iran

Directory of Open Access Journals (Sweden)

Razieh Esfandtari

2014-06-01

Full Text Available Introduction: Breast milk is a complete food for growing children until 6 months of age, and mothers, as the most important child health care, play a decisive role in their growth. So promoting  their attitude toward the benefits of breastfeeding ensures guarantee child health in the future. This study aimed to assess maternal knowledge and attitude of Mashhad toward exclusive Breast Milk Feeding (BMFin the first 6 months of infant life.   Materials and Methods: This cross-sectional descriptive-analytic study was conducted on 190 mothers who referring to Yazd health-care centers for monitoring their 6-24 month year old infants. They completed questionnaire. Participants were selected by cluster and simple random sampling. Data were analyzed by descriptive- analytic tests and using SPSS 11.5.   Results: Mean score of maternal attitude toward exclusive BMF was 10.14±2.00 (out of 14 and maternal knowledge score toward advantages of breast milk was 10.12±2.015 (out of 14. The incidence of exclusive BMF in the first 6 months of life study was 72.9%. Child growth was as follows: excellent growth (24.5% and good growth (55.3%. ANOVA showed a significant difference between parents' education and maternal attitude and maternal knowledge towards exclusive BMF; whatever higher education of parents, more positive knowledge and attitude towards exclusive BMF (P

Analytic manifolds in uniform algebras

International Nuclear Information System (INIS)

Tonev, T.V.

1988-12-01

Here we extend Bear-Hile's result concerning the version of famous Bishop's theorem for one-dimensional analytic structures in two directions: for n-dimensional complex analytic manifolds, n>1, and for generalized analytic manifolds. 14 refs

Framework for pedagogical learning analytics

OpenAIRE

Heilala, Ville

2018-01-01

Learning analytics is an emergent technological practice and a multidisciplinary scientific discipline, which goal is to facilitate effective learning and knowledge of learning. In this design science research, I combine knowledge discovery process, a concept of pedagogical knowledge, ethics of learning analytics and microservice architecture. The result is a framework for pedagogical learning analytics. The framework is applied and evaluated in the context of agency analytics. The framework ...

The impact of repeat-testing of common chemistry analytes at critical concentrations.

Science.gov (United States)

Onyenekwu, Chinelo P; Hudson, Careen L; Zemlin, Annalise E; Erasmus, Rajiv T

2014-12-01

Early notification of critical values by the clinical laboratory to the treating physician is a requirement for accreditation and is essential for effective patient management. Many laboratories automatically repeat a critical value before reporting it to prevent possible misdiagnosis. Given today's advanced instrumentation and quality assurance practices, we questioned the validity of this approach. We performed an audit of repeat-testing in our laboratory to assess for significant differences between initial and repeated test results, estimate the delay caused by repeat-testing and to quantify the cost of repeating these assays. A retrospective audit of repeat-tests for sodium, potassium, calcium and magnesium in the first quarter of 2013 at Tygerberg Academic Laboratory was conducted. Data on the initial and repeat-test values and the time that they were performed was extracted from our laboratory information system. The Clinical Laboratory Improvement Amendment criteria for allowable error were employed to assess for significant difference between results. A total of 2308 repeated tests were studied. There was no significant difference in 2291 (99.3%) of the samples. The average delay ranged from 35 min for magnesium to 42 min for sodium and calcium. At least 2.9% of laboratory running costs for the analytes was spent on repeating them. The practice of repeating a critical test result appears unnecessary as it yields similar results, delays notification to the treating clinician and increases laboratory running costs.

Alkaptonuria diagnosed in a 4-month-old baby girl: a case report

Science.gov (United States)

Datta, Asok K; Mandal, Syamali; Dasgupta, Anindya; Ghosh, Tarun K

2008-01-01

The mother of a four month old female baby attended in the well baby clinic with the complaint of black staining of the diaper after few minutes of urination. The baby was born of a non consanguineous marriage, healthy and breast fed. Mother noticed that stain first at the age of two and half month. The urine when kept in a test tube for two hours turned black. Laboratory examination of urine revealed increased concentration of homogentisic acid. The patient was diagnosed as alkaptonuria. PMID:19014543

Analytical TEM investigations of nanoscale magnetic materials

International Nuclear Information System (INIS)

Meingast, A.

2015-01-01

element identification or, an absolute quantification is possible. Moreover, the parallel acquisition of EDXS and EELS signals allows combining the strength of each respective technique. A careful and precise sample preparation is crucial and knowledge and suitable methods had to be developed. Preparation induced modifications of the investigated material was minimized by identifying changes to the material during thinning to electron transparency. Reducing surface amorphization of TEM specimens and moreover identifying and quantifying surface oxidation was an important factor. Questions regarding the structural architecture of three diverse magnetic materials down to the atomic level have been addressed, and elemental distributions have been determined quantitatively. The first part of the results treats structural and analytical results of crystalline nanocubes. These cubes have dimensions below 30 nm, and represent a class of materials to exploit magnetic exchange coupling on a nanometer scale. Knowledge about the elemental distribution on a nanometer basis within a nanocube is necessary to tailor the magnetic properties. Analytical investigations deal with the determination of the oxidation state of iron oxide reference nanocrystals and the elemental distribution within a multi-component system. Transition metal doped gallium nitride (GaN) falling into the class of dilute magnetic semiconductors was investigated by various high resolution imaging techniques and spectroscopic methods for resolving morphologies and dopant concentrations. The doping of GaN is intended to provide additional magnetic functionalities to the semiconducting material used for future spintronic devices. Quantitative EELS measurements resolved that Mn was incorporated either in a homogeneous way or added to GaN in a pulsed way, leading to a layered doping. Iron was used as another potential dopant for GaN. Hereby specific growth procedures enabled the formation of a layer of iron

Temporal course of cerebrospinal fluid dynamics and amyloid accumulation in the aging rat brain from three to thirty months

Directory of Open Access Journals (Sweden)

Chiu Catherine

2012-01-01

Full Text Available Abstract Background Amyloid accumulation in the brain parenchyma is a hallmark of Alzheimer's disease (AD and is seen in normal aging. Alterations in cerebrospinal fluid (CSF dynamics are also associated with normal aging and AD. This study analyzed CSF volume, production and turnover rate in relation to amyloid-beta peptide (Aβ accumulation in the aging rat brain. Methods Aging Fischer 344/Brown-Norway hybrid rats at 3, 12, 20, and 30 months were studied. CSF production was measured by ventriculo-cisternal perfusion with blue dextran in artificial CSF; CSF volume by MRI; and CSF turnover rate by dividing the CSF production rate by the volume of the CSF space. Aβ40 and Aβ42 concentrations in the cortex and hippocampus were measured by ELISA. Results There was a significant linear increase in total cranial CSF volume with age: 3-20 months (p p p p -1 to 12 months (11.30 day-1 and then a decrease to 20 months (10.23 day-1 and 30 months (6.62 day-1. Aβ40 and Aβ42 concentrations in brain increased from 3-30 months (p Conclusions In young rats there is no correlation between CSF turnover and Aβ brain concentrations. After 12 months, CSF turnover decreases as brain Aβ continues to accumulate. This decrease in CSF turnover rate may be one of several clearance pathway alterations that influence age-related accumulation of brain amyloid.

Estimating absorption coefficients of colored dissolved organic matter (CDOM) using a semi-analytical algorithm for Southern Beaufort Sea (Canadian Arctic) waters: application to deriving concentrations of dissolved organic carbon from space

Science.gov (United States)

Matsuoka, A.; Hooker, S. B.; Bricaud, A.; Gentili, B.; Babin, M.

2012-10-01

A series of papers have suggested that freshwater discharge, including a large amount of dissolved organic matter (DOM), has increased since the middle of the 20th century. In this study, a semi-analytical algorithm for estimating light absorption coefficients of the colored fraction of DOM (CDOM) was developed for Southern Beaufort Sea waters using remote sensing reflectance at six wavelengths in the visible spectral domain corresponding to MODIS ocean color sensor. This algorithm allows to separate colored detrital matter (CDM) into CDOM and non-algal particles (NAP) by determining NAP absorption using an empirical relationship between NAP absorption and particle backscattering coefficients. Evaluation using independent datasets, that were not used for developing the algorithm, showed that CDOM absorption can be estimated accurately to within an uncertainty of 35% and 50% for oceanic and turbid waters, respectively. In situ measurements showed that dissolved organic carbon (DOC) concentrations were tightly correlated with CDOM absorption (r2 = 0.97). By combining the CDOM absorption algorithm together with the DOC versus CDOM relationship, it is now possible to estimate DOC concentrations in the near-surface layer of the Southern Beaufort Sea using satellite ocean color data. DOC concentrations in the surface waters were estimated using MODIS ocean color data, and the estimates showed reasonable values compared to in situ measurements. We propose a routine and near real-time method for deriving DOC concentrations from space, which may open the way to an estimate of DOC budgets for Arctic coastal waters.

SERS-based application in food analytics (Conference Presentation)

Science.gov (United States)

Cialla-May, Dana; Radu, Andreea; Jahn, Martin; Weber, Karina; Popp, Jürgen

2017-02-01

To establish detection schemes in life science applications, specific and sensitive methods allowing for fast detection times are required. Due to the interaction of molecules with strong electromagnetic fields excited at metallic nanostructures, the molecular fingerprint specific Raman spectrum is increased by several orders of magnitude. This effect is described as surface-enhanced Raman spectroscopy (SERS) and became a very powerful analytical tool in many fields of application. Within this presentation, we will introduce innovative bottom-up strategies to prepare SERS-active nanostructures coated with a lipophilic sensor layer. To do so, the food colorant Sudan III, an indirect carcinogen substance found in chili powder, palm oil or spice mixtures, is detected quantitatively in the background of the competitor riboflavin as well as paprika powder extracts. The SERS-based detection of azorubine (E122) in commercial available beverages with different complexity (e.g. sugar content, alcohol concentration) illustrates the strong potential of SERS as a qualitative as well as semiquantitative prescan method in food analytics. Here, a good agreement between the estimated concentration employing SERS as well as the gold standard technique HPLC, a highly laborious method, is found. Finally, SERS is applied to detect vitamin B2 and B12 in cereals as well as the estimate the ratio of lycopene and β-carotene in tomatoes. Acknowledgement: Funding the projects "QuantiSERS" and "Jenaer Biochip Initiative 2.0" within the framework "InnoProfile Transfer - Unternehmen Region" the Federal Ministry of Education and Research, Germany (BMBF) is gratefully acknowledged.

Assessment of metal concentrations in sediment samples from Billings Reservoir, Rio Grande tributary, Sao Paulo, Brazil

International Nuclear Information System (INIS)

Bostelmann, Eleine

2006-01-01

The present study chemically characterized sediment samples from the Billings reservoir, Rio Grande tributary, in the Metropolitan region of Sao Paulo, by determining metal concentration and other elements of interest. The chosen chemical parameters for this characterization were Aluminum, Arsenic, Barium, Cadmium, Copper, Chromium, Iron, Lead, Manganese, Mercury, Nickel, Selenium and Zinco. These parameters are also used in the water quality index, with the exception of Selenium. The concentrations were determined through different analytical techniques such as atomic absorption spectrometry (FAAS, GFAAS and CVAAS), optical emission spectrometry (ICP OES) and neutron activation analysis. These analytical methodologies were assessed for precision, accuracy and detection and/or quantification limits for the sediment elements in question. Advantages and disadvantages of each technique for each element and its concentration were also discussed. From these assessments the most adequate technique was selected for the routine analysis of sediment samples for each element concentration determination. This assessment verified also that digestion in a closed microwave system with nitric acid is efficient for the evaluation of extracted metals of environmental interest. The analytical techniques chosen were equally efficient for metals determination. In the case of Cd and Pb, the FAAS technique was selected due to better results than ICP OES, as it does not present matrix interference. The concentration values obtained for metals As, Cd, Cu, Cr, Hg, Ni, Pb and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) TEL and PEL values. (author)

Assessment of metal concentrations in sediment samples from Billings reservoir, Rio Grande tributary, Sao Paulo, Brazil

International Nuclear Information System (INIS)

Bostelmann, Eleine

2006-01-01

The present study chemically characterized sediment samples from the Billings reservoir, Rio Grande tributary, in the Metropolitan region of Sao Paulo, by determining metal concentration and other elements of interest. The chosen chemical parameters for this characterization were Aluminum, Arsenic, Barium, Cadmium, Copper, Chromium, Iron, Lead, Manganese, Mercury, Nickel, Selenium and Zinc. These parameters are also used in the water quality index, with the exception of Selenium. The concentrations were determined through different analytical techniques such as atomic absorption spectrometry (FAAS, GFAAS and CVAAS), optical emission spectrometry (ICP OES) and neutron activation analysis. These analytical methodologies were assessed for precision, accuracy and detection and/or quantification limits for the sediment elements in question. Advantages and disadvantages of each technique for each element and its concentration were also discussed. From these assessment the most adequate technique was selected for the routine analysis of sediment samples for each element concentration determination. This assessment verified also that digestion in a closed microwave system with nitric acid is efficient for the evaluation of extracted metals of environmental interest. The analytical techniques chosen were equally efficient for metals determination. In the case of Cd and Pb, the FAAS technique was selected due to better results than ICP OES, as it does not present matrix interference. The concentration values obtained for metals As, Cd, Cu, Cr, Hg, Ni, Pb and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) TEL and PEL values. (author)

Coated Particle and Deep Burn Fuels Monthly Highlights December 2010

International Nuclear Information System (INIS)

Snead, Lance Lewis; Bell, Gary L.; Besmann, Theodore M.

2011-01-01

During FY 2011 the CP and DB Program will report Highlights on a monthly basis, but will no longer produce Quarterly Progress Reports. Technical details that were previously included in the quarterly reports will be included in the appropriate Milestone Reports that are submitted to FCRD Program Management. These reports will also be uploaded to the Deep Burn website. The Monthly Highlights report for November 2010, ORNL/TM-2010/323, was distributed to program participants on December 9, 2010. The final Quarterly for FY 2010, Deep Burn Program Quarterly Report for July - September 2010, ORNL/TM-2010/301, was announced to program participants and posted to the website on December 28, 2010. This report discusses the following: (1) Thermochemical Data and Model Development - (a) Thermochemical Modeling, (b) Core Design Optimization in the HTR (high temperature helium-cooled reactor) Pebble Bed Design (INL), (c) Radiation Damage and Properties; (2) TRISO (tri-structural isotropic) Development - (a) TRU (transuranic elements) Kernel Development, (b) Coating Development; (3) LWR Fully Ceramic Fuel - (a) FCM Fabrication Development, (b) FCM Irradiation Testing (ORNL); (4) Fuel Performance and Analytical Analysis - Fuel Performance Modeling (ORNL).

Estimated exposures to perfluorinated compounds in infancy predict attenuated vaccine antibody concentrations at age 5-years.

Science.gov (United States)

Grandjean, Philippe; Heilmann, Carsten; Weihe, Pal; Nielsen, Flemming; Mogensen, Ulla B; Timmermann, Amalie; Budtz-Jørgensen, Esben

2017-12-01

Perfluorinated alkylate substances (PFASs) are highly persistent and may cause immunotoxic effects. PFAS-associated attenuated antibody responses to childhood vaccines may be affected by PFAS exposures during infancy, where breastfeeding adds to PFAS exposures. Of 490 members of a Faroese birth cohort, 275 and 349 participated in clinical examinations and provided blood samples at ages 18 months and 5 years. PFAS concentrations were measured at birth and at the clinical examinations. Using information on duration of breastfeeding, serum-PFAS concentration profiles during infancy were estimated. As outcomes, serum concentrations of antibodies against tetanus and diphtheria vaccines were determined at age 5. Data from a previous cohort born eight years earlier were available for pooled analyses. Pre-natal exposure showed inverse associations with the antibody concentrations five years later, with decreases by up to about 20% for each two-fold higher exposure, while associations for serum concentrations at ages 18 months and 5 years were weaker. Modeling of serum-PFAS concentration showed levels for age 18 months that were similar to those measured. Concentrations estimated for ages 3 and 6 months showed the strongest inverse associations with antibody concentrations at age 5 years, particularly for tetanus. Joint analyses showed statistically significant decreases in tetanus antibody concentrations by 19-29% at age 5 for each doubling of the PFAS exposure in early infancy. These findings support the notion that the developing adaptive immune system is particularly vulnerable to immunotoxicity during infancy. This vulnerability appears to be the greatest during the first 6 months after birth, where PFAS exposures are affected by breast-feeding.

Diffusion influence on Michaelis Menten kinetics: II. The low substrate concentration limit

Science.gov (United States)

Kim, Hyojoon; Shin, Kook Joe

2007-02-01

The diffusion-influenced Michaelis-Menten kinetics in the low substrate concentration limit is studied in one and three dimensions. For the initial pair distribution of enzyme and substrate, we obtain the exact analytical results. We find that at short times the diffusion effect can make the reaction rate faster. The concentration deviations of the substrate and enzyme show t-1/2 and t-3/2 power-law behaviours in one and three dimensions, respectively, at long times. On the other hand, the average lifetime of the intermediate is independent of the initial state in one dimension, while it depends on the initial state in three dimensions. The ultimate production yield approaches unity in one dimension but it reaches a different value depending on other parameters in three dimensions. We also obtain the analytical results for the initial random distribution.

Diffusion influence on Michaelis-Menten kinetics: II. The low substrate concentration limit

International Nuclear Information System (INIS)

Kim, Hyojoon; Shin, Kook Joe

2007-01-01

The diffusion-influenced Michaelis-Menten kinetics in the low substrate concentration limit is studied in one and three dimensions. For the initial pair distribution of enzyme and substrate, we obtain the exact analytical results. We find that at short times the diffusion effect can make the reaction rate faster. The concentration deviations of the substrate and enzyme show t -1/2 and t -3/2 power-law behaviours in one and three dimensions, respectively, at long times. On the other hand, the average lifetime of the intermediate is independent of the initial state in one dimension, while it depends on the initial state in three dimensions. The ultimate production yield approaches unity in one dimension but it reaches a different value depending on other parameters in three dimensions. We also obtain the analytical results for the initial random distribution

Limitless Analytic Elements

Science.gov (United States)

Strack, O. D. L.

2018-02-01

We present equations for new limitless analytic line elements. These elements possess a virtually unlimited number of degrees of freedom. We apply these new limitless analytic elements to head-specified boundaries and to problems with inhomogeneities in hydraulic conductivity. Applications of these new analytic elements to practical problems involving head-specified boundaries require the solution of a very large number of equations. To make the new elements useful in practice, an efficient iterative scheme is required. We present an improved version of the scheme presented by Bandilla et al. (2007), based on the application of Cauchy integrals. The limitless analytic elements are useful when modeling strings of elements, rivers for example, where local conditions are difficult to model, e.g., when a well is close to a river. The solution of such problems is facilitated by increasing the order of the elements to obtain a good solution. This makes it unnecessary to resort to dividing the element in question into many smaller elements to obtain a satisfactory solution.

New trends in the analytical determination of emerging contaminants and their transformation products in environmental waters.

Science.gov (United States)

Agüera, Ana; Martínez Bueno, María Jesús; Fernández-Alba, Amadeo R

2013-06-01

Since the so-called emerging contaminants were established as a new group of pollutants of environmental concern, a great effort has been devoted to the knowledge of their distribution, fate and effects in the environment. After more than 20 years of work, a significant improvement in knowledge about these contaminants has been achieved, but there is still a large gap of information on the growing number of new potential contaminants that are appearing and especially of their unpredictable transformation products. Although the environmental problem arising from emerging contaminants must be addressed from an interdisciplinary point of view, it is obvious that analytical chemistry plays an important role as the first step of the study, as it allows establishing the presence of chemicals in the environment, estimate their concentration levels, identify sources and determine their degradation pathways. These tasks involve serious difficulties requiring different analytical solutions adjusted to purpose. Thus, the complexity of the matrices requires highly selective analytical methods; the large number and variety of compounds potentially present in the samples demands the application of wide scope methods; the low concentrations at which these contaminants are present in the samples require a high detection sensitivity, and high demands on the confirmation and high structural information are needed for the characterisation of unknowns. New developments on analytical instrumentation have been applied to solve these difficulties. Furthermore and not less important has been the development of new specific software packages intended for data acquisition and, in particular, for post-run analysis. Thus, the use of sophisticated software tools has allowed successful screening analysis, determining several hundreds of analytes, and assisted in the structural elucidation of unknown compounds in a timely manner.

Thyroglobulin assay in fluids from lymph node fine needle-aspiration washout: influence of pre-analytical conditions.

Science.gov (United States)

Casson, Florence Boux de; Moal, Valérie; Gauchez, Anne-Sophie; Moineau, Marie-Pierre; Sault, Corinne; Schlageter, Marie-Hélène; Massart, Catherine

2017-04-01

The aim of this study was to evaluate the pre-analytical factors contributing to uncertainty in thyroglobulin measurement in fluids from fine-needle aspiration (FNA) washout of cervical lymph nodes. We studied pre-analytical stability, in different conditions, of 41 samples prepared with concentrated solutions of thyroglobulin (FNA washout or certified standard) diluted in physiological saline solution or buffer containing 6% albumin. In this buffer, over time, no changes in thyroglobulin concentrations were observed in all storage conditions tested. In albumin free saline solution, thyroglobulin recovery rates depended on initial sample concentrations and on modalities of their conservation (in conventional storage tubes, recovery mean was 56% after 3 hours-storage at room temperature and 19% after 24 hours-storage for concentrations ranged from 2 to 183 μg/L; recovery was 95%, after 3 hours or 24 hours-storage at room temperature, for a concentration of 5,656 μg/L). We show here that these results are due to non-specific adsorption of thyroglobulin in storage tubes, which depends on sample protein concentrations. We also show that possible contamination of fluids from FNA washout by plasma proteins do not always adequately prevent this adsorption. In conclusion, non-specific adsorption in storage tubes strongly contributes to uncertainty in thyroglobulin measurement in physiological saline solution. It is therefore recommended, for FNA washout, to use a buffer containing proteins provided by the laboratory.

Elemental concentration distribution in human fingernails – A 3D study

International Nuclear Information System (INIS)

Pineda-Vargas, C.A.; Mars, J.A.; Gihwala, D.

2012-01-01

The verification of pathologies has normally been based on analysis of blood (serum and plasma), and physiological tissue. Recently, nails and in particular human fingernails have become an important medium for pathological studies, especially those of environmental origin. The analytical technique of PIXE has been used extensively in the analysis of industrial samples and human tissue specimens. The application of the analytical technique to nails has been mainly to bulk samples. In this study we use micro-PIXE and -RBS, as both complementary and supplementary, to determine the elemental concentration distribution of human fingernails of individuals. We report on the 3D quantitative elemental concentration distributions (QECDs) of various elements that include C, N and O as major elements (10–20%), P, S, Cl, K and Ca as minor elements (1–10%) and Fe, Mn, Zn, Ti, Na, Mg, Cu, Ni, Cr, Rb, Br, Sr and Se as trace elements (less than 1%). For PIXE and RBS the specimens were bombarded with a 3 MeV proton beam. To ascertain any correlations in the quantitative elemental concentration distributions, a linear traverse analysis was performed across the width of the nail. Elemental distribution correlations were also obtained.

Nanomaterials in consumer products: a challenging analytical problem

Directory of Open Access Journals (Sweden)

Catia eContado

2015-08-01

Full Text Available Many products used in everyday life are made with the assistance of nanotechnologies. Cosmetic, pharmaceuticals, sunscreen, powdered food are only few examples of end products containing nano-sized particles (NPs, generally added to improve the product quality. To evaluate correctly benefits versus risks of engineered nanomaterials and consequently to legislate in favor of consumer’s protection, it is necessary to know the hazards connected with the exposure levels. This information implies transversal studies and a number of different competences.On analytical point of view the identification, quantification and characterization of NPs in food matrices and in cosmetic or personal care products pose significant challenges, because NPs are usually present at low concentration levels and the matrices, in which they are dispersed, are complexes and often incompatible with analytical instruments that would be required for their detection and characterization.This paper focused on some analytical techniques suitable for the detection, characterization and quantification of NPs in food and cosmetics products, reports their recent application in characterizing specific metal and metal-oxide NPs in these two important industrial and market sectors.The need of a characterization of the NPs as much as possible complete, matching complementary information about different metrics, possible achieved through validate procedures, is what clearly emerges from this research. More work should be done to produce standardized materials and to set-up methodologies to determine number-based size distributions and to get quantitative date about the NPs in such a complex matrices.

Nanomaterials in consumer products: a challenging analytical problem.

Science.gov (United States)

Contado, Catia

2015-01-01

Many products used in everyday life are made with the assistance of nanotechnologies. Cosmetic, pharmaceuticals, sunscreen, powdered food are only few examples of end products containing nano-sized particles (NPs), generally added to improve the product quality. To evaluate correctly benefits vs. risks of engineered nanomaterials and consequently to legislate in favor of consumer's protection, it is necessary to know the hazards connected with the exposure levels. This information implies transversal studies and a number of different competences. On analytical point of view the identification, quantification and characterization of NPs in food matrices and in cosmetic or personal care products pose significant challenges, because NPs are usually present at low concentration levels and the matrices, in which they are dispersed, are complexes and often incompatible with analytical instruments that would be required for their detection and characterization. This paper focused on some analytical techniques suitable for the detection, characterization and quantification of NPs in food and cosmetics products, reports their recent application in characterizing specific metal and metal-oxide NPs in these two important industrial and market sectors. The need of a characterization of the NPs as much as possible complete, matching complementary information about different metrics, possible achieved through validate procedures, is what clearly emerges from this research. More work should be done to produce standardized materials and to set-up methodologies to determine number-based size distributions and to get quantitative date about the NPs in such a complex matrices.

Estimating absorption coefficients of colored dissolved organic matter (CDOM using a semi-analytical algorithm for southern Beaufort Sea waters: application to deriving concentrations of dissolved organic carbon from space

Directory of Open Access Journals (Sweden)

A. Matsuoka

2013-02-01

Full Text Available A series of papers have suggested that freshwater discharge, including a large amount of dissolved organic matter (DOM, has increased since the middle of the 20th century. In this study, a semi-analytical algorithm for estimating light absorption coefficients of the colored fraction of DOM (CDOM was developed for southern Beaufort Sea waters using remote sensing reflectance at six wavelengths in the visible spectral domain corresponding to MODIS ocean color sensor. This algorithm allows the separation of colored detrital matter (CDM into CDOM and non-algal particles (NAP through the determination of NAP absorption using an empirical relationship between NAP absorption and particle backscattering coefficients. Evaluation using independent datasets, which were not used for developing the algorithm, showed that CDOM absorption can be estimated accurately to within an uncertainty of 35% and 50% for oceanic and coastal waters, respectively. A previous paper (Matsuoka et al., 2012 showed that dissolved organic carbon (DOC concentrations were tightly correlated with CDOM absorption in our study area (r² = 0.97. By combining the CDOM absorption algorithm together with the DOC versus CDOM relationship, it is now possible to estimate DOC concentrations in the near-surface layer of the southern Beaufort Sea using satellite ocean color data. DOC concentrations in the surface waters were estimated using MODIS ocean color data, and the estimates showed reasonable values compared to in situ measurements. We propose a routine and near real-time method for deriving DOC concentrations from space, which may open the way to an estimate of DOC budgets for Arctic coastal waters.

Pre-analytical Factors Influence Accuracy of Urine Spot Iodine Assessment in Epidemiological Surveys.

Science.gov (United States)

Doggui, Radhouene; El Ati-Hellal, Myriam; Traissac, Pierre; El Ati, Jalila

2018-03-26

Urinary iodine concentration (UIC) is commonly used to assess iodine status of subjects in epidemiological surveys. As pre-analytical factors are an important source of measurement error and studies about this phase are scarce, our objective was to assess the influence of urine sampling conditions on UIC, i.e., whether the child ate breakfast or not, urine void rank of the day, and time span between last meal and urine collection. A nationwide, two-stage, stratified, cross-sectional study including 1560 children (6-12 years) was performed in 2012. UIC was determined by the Sandell-Kolthoff method. Pre-analytical factors were assessed from children's mothers by using a questionnaire. Association between iodine status and pre-analytical factors were adjusted for one another and socio-economic characteristics by multivariate linear and multinomial regression models (RPR: relative prevalence ratios). Skipping breakfast prior to morning urine sampling decreased UIC by 40 to 50 μg/L and the proportion of UIC analytical factors is a key step toward improving accuracy and comparability of survey results for assessing iodine status from spot urine samples. These recommendations have to be evaluated by future research.

An analytic solution for one-dimensional diffusion of radionuclides from a waste package

International Nuclear Information System (INIS)

1985-01-01

This work implements an analytical solution for diffusion of radionuclides from a cylindrical waste form through the packing material into the surrounding host rock. Recent interest in predicting the performance of a proposed geological repository for nuclear waste has led to the development of several computer programs to predict the performance of such a repository for the next several millenia. These numerical codes are generally designed to accommodate a broad spectrum of geometrical configurations and repository conditions in order to accurately predict the behavior of the radionuclides in the repository environment. Confidence in such general purpose codes is gained by verifying the numerical modeling and the software through comparison of the numerical predictions generated by these computer codes with analytical solutions to reasonably complex problems. The analysis discussed herein implements the analytic solution, proposed by J.C. Jaeger in 1941 for radial diffusion through two concentric circular cylinders. Jaeger's solution was applied to the problem of diffusional mass transfer from a long cylindrical waste form and subsequently into the surrounding geological formation. Analytic predictions of fractional release rates, including the effects of sorption, were generated. 6 refs., 2 figs., 2 tabs

Learning Analytics: drivers, developments and challenges

Directory of Open Access Journals (Sweden)

Rebecca Ferguson

2014-12-01

Full Text Available Learning analytics is a significant area of Technology-Enhanced Learning (TEL that has emerged during the last decade. This review of the field begins with an examination of the technological, educational and political factors that have driven the development of analytics in educational settings. It goes on to chart the emergence of learning analytics, including their origins in the 20th century, the development of data-driven analytics, the rise of learning-focused perspectives and the influence of national economic concerns. It next focuses on the relationships between learning analytics, educational data mining and academic analytics. Finally, it examines developing areas of learning analytics research, and identifies a series of future challenges.

Analytical mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

1990-01-01

This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

Analytical quadrics

CERN Document Server

Spain, Barry; Ulam, S; Stark, M

1960-01-01

Analytical Quadrics focuses on the analytical geometry of three dimensions. The book first discusses the theory of the plane, sphere, cone, cylinder, straight line, and central quadrics in their standard forms. The idea of the plane at infinity is introduced through the homogenous Cartesian coordinates and applied to the nature of the intersection of three planes and to the circular sections of quadrics. The text also focuses on paraboloid, including polar properties, center of a section, axes of plane section, and generators of hyperbolic paraboloid. The book also touches on homogenous coordi

Generalized Analytical Treatment Of The Source Strength In The Solution Of The Diffusion Equation

International Nuclear Information System (INIS)

Essa, Kh.S.M.; EI-Otaify, M.S.

2007-01-01

The source release strength (which is an integral part of the mathematical formulation of the diffusion equation) together with the boundary conditions leads to three different forms of the diffusion equation. The obtained forms have been solved analytically under different boundary conditions, by using transformation of axis, cosine, and Fourier transformation. Three equivalent alternative mathematical formulations of the problem have been obtained. The estimated solution of the concentrations at the ground source has been used for comparison with observed concentrations data for SF 6 tracer experiments in low wind and unstable conditions at lIT Delhi sports ground. A good agreement between estimated and observed concentrations is found

A critical analysis of climatic influences on indoor radon concentrations: Implications for seasonal correction.

Science.gov (United States)

Groves-Kirkby, Christopher J; Crockett, Robin G M; Denman, Antony R; Phillips, Paul S

2015-10-01

Although statistically-derived national Seasonal Correction Factors (SCFs) are conventionally used to convert sub-year radon concentration measurements to an annual mean, it has recently been suggested that external temperature could be used to derive local SCFs for short-term domestic measurements. To validate this approach, hitherto unanalysed radon and temperature data from an environmentally-stable location were analysed. Radon concentration and internal temperature were measured over periods totalling 1025 days during an overall period of 1762 days, the greatest continuous sampling period being 334 days, with corresponding meteorological data collected at a weather station 10 km distant. Mean daily, monthly and annual radon concentrations and internal temperatures were calculated. SCFs derived using monthly mean radon concentration, external temperature and internal-external temperature-difference were cross-correlated with each other and with published UK domestic SCF sets. Relatively good correlation exists between SCFs derived from radon concentration and internal-external temperature difference but correlation with external temperature, was markedly poorer. SCFs derived from external temperature correlate very well with published SCF tabulations, confirming that the complexity of deriving SCFs from temperature data may be outweighed by the convenience of using either of the existing domestic SCF tabulations. Mean monthly radon data fitted to a 12-month sinusoid showed reasonable correlation with many of the annual climatic parameter profiles, exceptions being atmospheric pressure, rainfall and internal temperature. Introducing an additional 6-month sinusoid enhanced correlation with these three parameters, the other correlations remaining essentially unchanged. Radon latency of the order of months in moisture-related parameters suggests that the principal driver for radon is total atmospheric moisture content rather than relative humidity. Copyright �

Simultaneous pre-concentration and separation on simple paper-based analytical device for protein analysis.

Science.gov (United States)

Niu, Ji-Cheng; Zhou, Ting; Niu, Li-Li; Xie, Zhen-Sheng; Fang, Fang; Yang, Fu-Quan; Wu, Zhi-Yong

2018-02-01

In this work, fast isoelectric focusing (IEF) was successfully implemented on an open paper fluidic channel for simultaneous concentration and separation of proteins from complex matrix. With this simple device, IEF can be finished in 10 min with a resolution of 0.03 pH units and concentration factor of 10, as estimated by color model proteins by smartphone-based colorimetric detection. Fast detection of albumin from human serum and glycated hemoglobin (HBA1c) from blood cell was demonstrated. In addition, off-line identification of the model proteins from the IEF fractions with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was also shown. This PAD IEF is potentially useful either for point of care test (POCT) or biomarker analysis as a cost-effective sample pretreatment method.

Analytical solution of electrohydrodynamic flow and transport in rectangular channels: inclusion of double layer effects

KAUST Repository

Joekar-Niasar, V.

2013-01-25

Upscaling electroosmosis in porous media is a challenge due to the complexity and scale-dependent nonlinearities of this coupled phenomenon. "Pore-network modeling" for upscaling electroosmosis from pore scale to Darcy scale can be considered as a promising approach. However, this method requires analytical solutions for flow and transport at pore scale. This study concentrates on the development of analytical solutions of flow and transport in a single rectangular channel under combined effects of electrohydrodynamic forces. These relations will be used in future works for pore-network modeling. The analytical solutions are valid for all regimes of overlapping electrical double layers and have the potential to be extended to nonlinear Boltzmann distribution. The innovative aspects of this study are (a) contribution of overlapping of electrical double layers to the Stokes flow as well as Nernst-Planck transport has been carefully included in the analytical solutions. (b) All important transport mechanisms including advection, diffusion, and electromigration have been included in the analytical solutions. (c) Fully algebraic relations developed in this study can be easily employed to upscale electroosmosis to Darcy scale using pore-network modeling. © 2013 Springer Science+Business Media Dordrecht.

Analytical solution of electrohydrodynamic flow and transport in rectangular channels: inclusion of double layer effects

KAUST Repository

Joekar-Niasar, V.; Schotting, R.; Leijnse, A.

2013-01-01

Upscaling electroosmosis in porous media is a challenge due to the complexity and scale-dependent nonlinearities of this coupled phenomenon. "Pore-network modeling" for upscaling electroosmosis from pore scale to Darcy scale can be considered as a promising approach. However, this method requires analytical solutions for flow and transport at pore scale. This study concentrates on the development of analytical solutions of flow and transport in a single rectangular channel under combined effects of electrohydrodynamic forces. These relations will be used in future works for pore-network modeling. The analytical solutions are valid for all regimes of overlapping electrical double layers and have the potential to be extended to nonlinear Boltzmann distribution. The innovative aspects of this study are (a) contribution of overlapping of electrical double layers to the Stokes flow as well as Nernst-Planck transport has been carefully included in the analytical solutions. (b) All important transport mechanisms including advection, diffusion, and electromigration have been included in the analytical solutions. (c) Fully algebraic relations developed in this study can be easily employed to upscale electroosmosis to Darcy scale using pore-network modeling. © 2013 Springer Science+Business Media Dordrecht.

Concentration profiles near an activated enzyme.

Science.gov (United States)

Park, Soohyung; Agmon, Noam

2008-09-25

When a resting enzyme is activated, substrate concentration profile evolves in its vicinity, ultimately tending to steady state. We use modern theories for many-body effects on diffusion-influenced reactions to derive approximate analytical expressions for the steady-state profile and the Laplace transform of the transient concentration profiles. These show excellent agreement with accurate many-particle Brownian-dynamics simulations for the Michaelis-Menten kinetics. The steady-state profile has a hyperbolic dependence on the distance of the substrate from the enzyme, albeit with a prefactor containing the complexity of the many-body effects. These are most conspicuous for the substrate concentration at the surface of the enzyme. It shows an interesting transition as a function of the enzyme turnover rate. When it is high, the contact concentration decays monotonically to steady state. However, for slow turnover it is nonmonotonic, showing a minimum due to reversible substrate binding, then a maximum due to diffusion of new substrate toward the enzyme, and finally decay to steady state. Under certain conditions one can obtain a good estimate for the critical value of the turnover rate constant at the transition.

Some recent developments in the surface-analytical application of X-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Gries, W.H.

1987-01-01

Standard depth profiles of an analyte deposited into (diffusion or ion implantation) or on (thin-film deposition) a plane surface can be analyzed for profile type and centroid depth or film thickness by means of a standardless method in which the matrix-attenuated signals of the fluorescing analyte measured at two different take-off angles are related to the mathematical distribution moments of the profile. For a binary thin film the element ratio can also be established. Results obtained on phosphorus profiles in silicon and on zinc sulphide optical coatings are referred to. The quantity or concentration level can be determined by use of a reference standard which may contain the analyte in an entirely different distribution. This simplifies the calibration of secondary reference standards. A good lateral resolution in the sub-millimeter range can be achieved with synchrotron radiation. A further improvement of lateral resolution is possible by direct excitation with electron microbeams, though at significantly inferior detection limits. (orig.)

Analytical methods manual for the Mineral Resource Surveys Program, U.S. Geological Survey

Science.gov (United States)

Arbogast, Belinda F.

1996-01-01

The analytical methods validated by the Mineral Resource Surveys Program, Geologic Division, is the subject of this manual. This edition replaces the methods portion of Open-File Report 90-668 published in 1990. Newer methods may be used which have been approved by the quality assurance (QA) project and are on file with the QA coordinator.This manual is intended primarily for use by laboratory scientists; this manual can also assist laboratory users to evaluate the data they receive. The analytical methods are written in a step by step approach so that they may be used as a training tool and provide detailed documentation of the procedures for quality assurance. A "Catalog of Services" is available for customer (submitter) use with brief listings of:the element(s)/species determined,method of determination,reference to cite,contact person,summary of the technique,and analyte concentration range.For a copy please contact the Branch office at (303) 236-1800 or fax (303) 236-3200.

FEASIBILITY OF INVESTMENT IN BUSINESS ANALYTICS

Directory of Open Access Journals (Sweden)

Mladen Varga

2007-12-01

Full Text Available Trends in data processing for decision support show that business users need business analytics, i.e. analytical applications which incorporate a variety of business oriented data analysis techniques and task-specific knowledge. The paper discusses the feasibility of investment in two models of implementing business analytics: custom development and packed analytical applications. The consequences of both models are shown on two models of business analytics implementation in Croatia.

A characterization of dilation-analytic operators

International Nuclear Information System (INIS)

Balslev, E.; Grossmann, A.; Paul, T.

1986-01-01

Dilation analytic vectors and operators are characterized in a new representation of quantum mechanical states through functions analytic on the upper half-plane. In this space H o -bounded operators are integral operators and criteria for dilation analyticity are given in terms of analytic continuation outside of the half-plane for functions and for kernels. A sufficient condition is given for an integral operator in momentum space to be dilation-analytic

Collaborative Visual Analytics: A Health Analytics Approach to Injury Prevention

Directory of Open Access Journals (Sweden)

Samar Al-Hajj

2017-09-01

Full Text Available Background: Accurate understanding of complex health data is critical in order to deal with wicked health problems and make timely decisions. Wicked problems refer to ill-structured and dynamic problems that combine multidimensional elements, which often preclude the conventional problem solving approach. This pilot study introduces visual analytics (VA methods to multi-stakeholder decision-making sessions about child injury prevention; Methods: Inspired by the Delphi method, we introduced a novel methodology—group analytics (GA. GA was pilot-tested to evaluate the impact of collaborative visual analytics on facilitating problem solving and supporting decision-making. We conducted two GA sessions. Collected data included stakeholders’ observations, audio and video recordings, questionnaires, and follow up interviews. The GA sessions were analyzed using the Joint Activity Theory protocol analysis methods; Results: The GA methodology triggered the emergence of ‘common ground’ among stakeholders. This common ground evolved throughout the sessions to enhance stakeholders’ verbal and non-verbal communication, as well as coordination of joint activities and ultimately collaboration on problem solving and decision-making; Conclusions: Understanding complex health data is necessary for informed decisions. Equally important, in this case, is the use of the group analytics methodology to achieve ‘common ground’ among diverse stakeholders about health data and their implications.

Collaborative Visual Analytics: A Health Analytics Approach to Injury Prevention.

Science.gov (United States)

Al-Hajj, Samar; Fisher, Brian; Smith, Jennifer; Pike, Ian

2017-09-12

Background : Accurate understanding of complex health data is critical in order to deal with wicked health problems and make timely decisions. Wicked problems refer to ill-structured and dynamic problems that combine multidimensional elements, which often preclude the conventional problem solving approach. This pilot study introduces visual analytics (VA) methods to multi-stakeholder decision-making sessions about child injury prevention; Methods : Inspired by the Delphi method, we introduced a novel methodology-group analytics (GA). GA was pilot-tested to evaluate the impact of collaborative visual analytics on facilitating problem solving and supporting decision-making. We conducted two GA sessions. Collected data included stakeholders' observations, audio and video recordings, questionnaires, and follow up interviews. The GA sessions were analyzed using the Joint Activity Theory protocol analysis methods; Results : The GA methodology triggered the emergence of ' common g round ' among stakeholders. This common ground evolved throughout the sessions to enhance stakeholders' verbal and non-verbal communication, as well as coordination of joint activities and ultimately collaboration on problem solving and decision-making; Conclusion s : Understanding complex health data is necessary for informed decisions. Equally important, in this case, is the use of the group analytics methodology to achieve ' common ground' among diverse stakeholders about health data and their implications.

The pre, post brachytherapy and postoperative CEA serum concentration of 53 rectal cancer patients

International Nuclear Information System (INIS)

Nguyen Thanh Danh; Nguyen Kim Luu; Phan Van Dan

2008-01-01

CEA serum concentration level of 53 rectal cancer patients was measured at moments pre, post brachytherapy (45 Gy), post surgery one week, 6 months and 12 months. Response to radiation with reduce CEA serum concentration was achieved in 20/53 patients (37,7%), mainly at staging Dukes B, C. Postoperative CEA level of patients significantly decreased, especially in resection group. (author)

Analytical characterization of pure and blended watermelon (citrullus lanatus) oil: impact of blending on oxidative stability

International Nuclear Information System (INIS)

Azeem, M.W.; Nadeem, M.

2015-01-01

Analytical characterization of pure, blended watermelon (Citrulluslanatus) oil and impact of blending on oxidative stability was investigated. Watermelon oil was added with mango (Mangiferaindica L.) kernel oil at four different concentrations 5, 10, 15 and 20% (B 1, B2, B3 and B4) and referenced with a control (100% watermelon oil). All the blends were stored in transparent PET bottles at ambient temperature (25-28 degree C) for 3 months; storage stability was assessed at the interval of 1 month. Free fatty acid, unsaponifiable matter, saponification value, refractive index and iodine value of watermelon seed oil and mango kernel oil was 1.38%, 0.34%; 0.71%, 1.68%; 198, 193; 1.468, 1.457; 107.51, 54.62, respectively. The tocopherol content of watermelon oil, mango kernel oil, B1, B2, B3 and B4 was 127.49, 205.44, 135.24, 144.52, 156.81 and 169.34 mg/kg. delta tocopherol in watermelon oil, mango kernel oil, B1, B2, B3 and B4 was 55.26, 34.81, 53.64, 51.27, 50.14 and 48.23 mg/kg. Concentration of linoleic acid decreased from 50.78% to 30.17% when 40% mango kernel oil was added to watermelon oil. Oleic acid increased from 22.89% in watermelon oil to 25.19%, 28.84% and 30.64% in B1, B2, B3 and B4. The increase in peroxide value of watermelon oil, B1, B2, B3 and B4 was 10.07, 9.56, 7.62, 5.17 and 2.87 (meqO/sub 2//kg) in a time dependent manner. Induction period of pure watermelon oil was less than mango kernel oil and blends. These results suggest that chemical characteristics and oxidative stability of pure watermelon oil can be improved by blending with mango kernel oil. (author)

Analytical Characterization of Pure and Blended Watermelon (Citrullus lanatus oil: Impact of Blending on Oxidative Stability

Directory of Open Access Journals (Sweden)

Muhammad Waqar Azeem

2015-06-01

Full Text Available Analytical characterization of pure, blended watermelon (Citrulluslanatus oil and impact of blending on oxidative stability was investigated. Watermelon oil was added with mango (Mangiferaindica L. kernel oil at four different concentrations 5, 10, 15 and 20% (B1, B2, B3 and B4 and referenced with a control (100% watermelon oil. All the blends were stored in transparent PET bottles at ambient temperature (25-28oC for 3 months; storage stability was assessed at the interval of 1 month. Free fatty acid, unsaponifiable matter, saponification value, refractive index and iodine value of watermelon seed oil and mango kernel oil was 1.38%, 0.34%; 0.71%, 1.68%; 198, 193; 1.468, 1.457; 107.51, 54.62, respectively. The α tocopherol content of watermelon oil, mango kernel oil, B1, B2, B3 and B4 was 127.49, 205.44, 135.24, 144.52, 156.81 and 169.34 mg/kg. δ tocopherol in watermelon oil, mango kernel oil, B1, B2, B3 and B4 was 55.26, 34.81, 53.64, 51.27, 50.14 and 48.23 mg/kg. Concentration of linoleic acid decreased from 50.78% to 30.17% when 40% mango kernel oil was added to watermelon oil. Oleic acid increased from 22.89% in watermelon oil to 25.19%, 28.84% and 30.64% in B1, B2, B3 and B4. The increase in peroxide value of watermelon oil, B1, B2, B3 and B4 was 10.07, 9.56, 7.62, 5.17 and 2.87 (meqO2/kg in a time dependent manner. Induction period of pure watermelon oil was less than mango kernel oil and blends. These results suggest that chemical characteristics and oxidative stability of pure watermelon oil can be improved by blending with mango kernel oil.

Mild pituitary phenotype in 3- and 12-month-old Aip-deficient male mice.

Science.gov (United States)

Lecoq, Anne-Lise; Zizzari, Philippe; Hage, Mirella; Decourtye, Lyvianne; Adam, Clovis; Viengchareun, Say; Veldhuis, Johannes D; Geoffroy, Valérie; Lombès, Marc; Tolle, Virginie; Guillou, Anne; Karhu, Auli; Kappeler, Laurent; Chanson, Philippe; Kamenický, Peter

2016-10-01

Germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene predispose humans to pituitary adenomas, particularly of the somatotroph lineage. Mice with global heterozygous inactivation of Aip (Aip(+/-)) also develop pituitary adenomas but differ from AIP-mutated patients by the high penetrance of pituitary disease. The endocrine phenotype of these mice is unknown. The aim of this study was to determine the endocrine phenotype of Aip(+/-) mice by assessing the somatic growth, ultradian pattern of GH secretion and IGF1 concentrations of longitudinally followed male mice at 3 and 12 months of age. As the early stages of pituitary tumorigenesis are controversial, we also studied the pituitary histology and somatotroph cell proliferation in these mice. Aip(+/-) mice did not develop gigantism but exhibited a leaner phenotype than wild-type mice. Analysis of GH pulsatility by deconvolution in 12-month-old Aip(+/-) mice showed a mild increase in total GH secretion, a conserved GH pulsatility pattern, but a normal IGF1 concentration. No pituitary adenomas were detected up to 12 months of age. An increased ex vivo response to GHRH of pituitary explants from 3-month-old Aip(+/-) mice, together with areas of enlarged acini identified on reticulin staining in the pituitary of some Aip(+/-) mice, was suggestive of somatotroph hyperplasia. Global heterozygous Aip deficiency in mice is accompanied by subtle increase in GH secretion, which does not result in gigantism. The absence of pituitary adenomas in 12-month-old Aip(+/-) mice in our experimental conditions demonstrates the important phenotypic variability of this congenic mouse model. © 2016 Society for Endocrinology.

Advanced business analytics

CERN Document Server

Lev, Benjamin

2015-01-01

The book describes advanced business analytics and shows how to apply them to many different professional areas of engineering and management. Each chapter of the book is contributed by a different author and covers a different area of business analytics. The book connects the analytic principles with business practice and provides an interface between the main disciplines of engineering/technology and the organizational, administrative and planning abilities of management. It also refers to other disciplines such as economy, finance, marketing, behavioral economics and risk analysis. This book is of special interest to engineers, economists and researchers who are developing new advances in engineering management but also to practitioners working on this subject.

Applying analytical ultracentrifugation to nanocrystal suspensions

Energy Technology Data Exchange (ETDEWEB)

Jamison, Jennifer A; Krueger, Karl M; Mayo, J T; Yavuz, Cafer T; Redden, Jacina J; Colvin, Vicki L, E-mail: colvin@rice.ed [Department of Chemistry, Rice University, 6100 Main Street, MS-60, Houston, TX 77005 (United States)

2009-09-02

While applied frequently in physical biochemistry to the study of protein complexes, the quantitative use of analytical ultracentrifugation (AUC) for nanocrystal analysis is relatively rare. Its application in nanoscience is potentially very powerful as it provides a measure of nanocrystal density, size and structure directly in the solution phase. Towards that end, this paper examines the best practices for applying data collection and analysis methods for AUC, geared towards the study of biomolecules, to the unique problems of nanoparticle analysis. Using uniform nanocrystals of cadmium selenide, we compared several schemes for analyzing raw sedimentation data. Comparable values of the mean sedimentation coefficients (s-value) were found using several popular analytical approaches; however, the distribution in sample s-values is best captured using the van Holde-Weischt algorithm. Measured s-values could be reproducibly collected if sample temperature and concentration were controlled; under these circumstances, the variability for average sedimentation values was typically 5%. The full shape of the distribution in s-values, however, is not easily subjected to quantitative interpretation. Moreover, the selection of the appropriate sedimentation speed is crucial for AUC of nanocrystals as the density of inorganic nanocrystals is much larger than that of solvents. Quantitative analysis of sedimentation properties will allow for better agreement between experimental and theoretical models of nanocrystal solution behavior, as well as providing deeper insight into the hydrodynamic size and solution properties of nanomaterials.

Analytical Solutions of Ionic Diffusion and Heat Conduction in Multilayered Porous Media

Directory of Open Access Journals (Sweden)

Yu Bai

2015-01-01

Full Text Available Ionic diffusion and heat conduction in a multiple layered porous medium have many important engineering applications. One of the examples is the chloride ions from deicers penetrating into concrete structures such as bridge decks. Different overlays can be placed on top of concrete surface to slowdown the chloride penetration. In this paper, the chloride ion diffusion equations were established for concrete structures with multiple layers of protective system. By using Laplace transformation, an analytical solution was developed first for chloride concentration profiles in two-layered system and then extended to multiple layered systems with nonconstant boundary conditions, including the constant boundary and linear boundary conditions. Because ionic diffusion in saturated media and heat conduction are governed by the same form of partial differential equations with different materials parameters, the analytical solution was further extended to handle heat conduction in a multiple layered system under nonconstant boundary conditions. The numerical results were compared with available test data. The basic trends of the analytical solution and the test data agreed quite well.

Learning Analytics: Readiness and Rewards

Science.gov (United States)

Friesen, Norm

2013-01-01

This position paper introduces the relatively new field of learning analytics, first by considering the relevant meanings of both "learning" and "analytics," and then by looking at two main levels at which learning analytics can be or has been implemented in educational organizations. Although integrated turnkey systems or…

Analytical and sampling problems in primary coolant circuits of PWR-type reactors

International Nuclear Information System (INIS)

Illy, H.

1980-10-01

Details of recent analytical methods on the analysis and sampling of a PWR primary coolant are given in the order as follows: sampling and preparation; analysis of the gases dissolved in the water; monitoring of radiating substances; checking of boric acid concentration which controls the reactivity. The bibliography of this work and directions for its use are published in a separate report: KFKI-80-48 (1980). (author)

Analytical Methodologies for the Determination of Endocrine Disrupting Compounds in Biological and Environmental Samples

Directory of Open Access Journals (Sweden)

Zoraida Sosa-Ferrera

2013-01-01

Full Text Available Endocrine-disruptor compounds (EDCs can mimic natural hormones and produce adverse effects in the endocrine functions by interacting with estrogen receptors. EDCs include both natural and synthetic chemicals, such as hormones, personal care products, surfactants, and flame retardants, among others. EDCs are characterised by their ubiquitous presence at trace-level concentrations and their wide diversity. Since the discovery of the adverse effects of these pollutants on wildlife and human health, analytical methods have been developed for their qualitative and quantitative determination. In particular, mass-based analytical methods show excellent sensitivity and precision for their quantification. This paper reviews recently published analytical methodologies for the sample preparation and for the determination of these compounds in different environmental and biological matrices by liquid chromatography coupled with mass spectrometry. The various sample preparation techniques are compared and discussed. In addition, recent developments and advances in this field are presented.

Pre-analytical and analytical factors influencing Alzheimer's disease cerebrospinal fluid biomarker variability.

Science.gov (United States)

Fourier, Anthony; Portelius, Erik; Zetterberg, Henrik; Blennow, Kaj; Quadrio, Isabelle; Perret-Liaudet, Armand

2015-09-20

A panel of cerebrospinal fluid (CSF) biomarkers including total Tau (t-Tau), phosphorylated Tau protein at residue 181 (p-Tau) and β-amyloid peptides (Aβ42 and Aβ40), is frequently used as an aid in Alzheimer's disease (AD) diagnosis for young patients with cognitive impairment, for predicting prodromal AD in mild cognitive impairment (MCI) subjects, for AD discrimination in atypical clinical phenotypes and for inclusion/exclusion and stratification of patients in clinical trials. Due to variability in absolute levels between laboratories, there is no consensus on medical cut-off value for the CSF AD signature. Thus, for full implementation of this core AD biomarker panel in clinical routine, this issue has to be solved. Variability can be explained both by pre-analytical and analytical factors. For example, the plastic tubes used for CSF collection and storage, the lack of reference material and the variability of the analytical protocols were identified as important sources of variability. The aim of this review is to highlight these pre-analytical and analytical factors and describe efforts done to counteract them in order to establish cut-off values for core CSF AD biomarkers. This review will give the current state of recommendations. Copyright © 2015. Published by Elsevier B.V.

Analytical estimation of effective charges at saturation in Poisson-Boltzmann cell models

International Nuclear Information System (INIS)

Trizac, Emmanuel; Aubouy, Miguel; Bocquet, Lyderic

2003-01-01

We propose a simple approximation scheme for computing the effective charges of highly charged colloids (spherical or cylindrical with infinite length). Within non-linear Poisson-Boltzmann theory, we start from an expression for the effective charge in the infinite-dilution limit which is asymptotically valid for large salt concentrations; this result is then extended to finite colloidal concentration, approximating the salt partitioning effect which relates the salt content in the suspension to that of a dialysing reservoir. This leads to an analytical expression for the effective charge as a function of colloid volume fraction and salt concentration. These results compare favourably with the effective charges at saturation (i.e. in the limit of large bare charge) computed numerically following the standard prescription proposed by Alexander et al within the cell model

Division of Analytical Chemistry, 1998

DEFF Research Database (Denmark)

Hansen, Elo Harald

1999-01-01

The article recounts the 1998 activities of the Division of Analytical Chemistry (DAC- formerly the Working Party on Analytical Chemistry, WPAC), which body is a division of the Federation of European Chemical Societies (FECS). Elo Harald Hansen is the Danish delegate, representing The Danish...... Chemical Society/The Society for Analytical Chemistry....

Certified reference materials for analytical quality control in neutron activation analysis

International Nuclear Information System (INIS)

Wee Boon Siong; Abdul Khalik Wood; Mohd Suhaimi Hamzah; Shamsiah Abdul Rahman; Mohd Suhaimi Elias; Nazaratul Ashifa Abdul Salim

2007-01-01

Analytical quality control in neutron activation analysis (NAA) requires the use of certified reference materials (CRM) in order to produce reliable analytical results. It is essential to evaluate the performance of NAA method when analyzing various sample matrices. Therefore, the CRM selected for an analysis should be suitable for the type of samples. There are many aspects such as concentration range, matrix match, sample size and uncertainty, which need to be considered when selecting a suitable CRM. Eventually, results of analysis of CRM were plotted into control charts in order to evaluate the qualify of the data. This is to ensure that the results are within the 95 % confidence interval as stipulated in the certificate of CRM. Thus, this article aims to discuss the uses of certified reference materials for quality control purposes in NAA involving various sample matrices. (author)

Reference values of amino acids and of common clinical chemistry in plasma of healthy infants aged 1 and 4 months.

Science.gov (United States)

Haschke-Becher, Elisabeth; Kainz, Alexander; Bachmann, Claude

2016-01-01

To compare plasma levels of amino acids and clinical chemistry parameters in healthy infants at 1 and 4 months of age and to establish corresponding reference limits. Data of three multicenter studies assessing the safety of new infant formulas were used. During these studies infants of both age-groups were either breast-fed or received formulas of low or high protein content. All samples were analyzed centrally in the same accredited laboratory. Plasma was collected from 521 infants in total, 157 boys and 135 girls aged 1 month and 121 boys and 108 girls aged 4 months. At the age of 1 month, 62 infants had received exclusively breast milk, 198 exclusively formula, and 27 both; in the 4-months age group corresponding numbers were 49, 158 and 18, respectively; for 9 infants, diet was unknown. Concentrations of most amino acids and clinical chemistry parameters differed significantly between both ages. Regardless of age, most plasma amino acid levels were comparable or lower in breast-fed than in formula-fed infants whereas at 1 month of age most clinical chemistry parameters were higher. While in breast-fed infants the plasma urea concentration decreased over 4 months of age, it increased in formula-fed infants. There were significant differences between infants fed a low and high protein formula. At both ages, high protein formulas resulted in significantly higher threonine, 2-aminobutyrate, and urea concentrations. For clinical use, age- and diet specific reference limits in infants are warranted.

Analytics for managers with Excel

CERN Document Server

Bell, Peter C

2013-01-01

Analytics is one of a number of terms which are used to describe a data-driven more scientific approach to management. Ability in analytics is an essential management skill: knowledge of data and analytics helps the manager to analyze decision situations, prevent problem situations from arising, identify new opportunities, and often enables many millions of dollars to be added to the bottom line for the organization.The objective of this book is to introduce analytics from the perspective of the general manager of a corporation. Rather than examine the details or attempt an encyclopaedic revie

STATISTICAL EVALUATION OF AN ANALYTICAL GC/MS METHOD FOR THE DETERMINATION OF LONG CHAIN FATTY ACIDS

Science.gov (United States)

In-depth evaluation of an analytical method to detect and quantify long chain fatty acids (C8 - C16) at trace level concentrations (25-1000 µg/l) is presented. The method requires derivatization of the acids with methanolic boron trifluoride, separation, and...

Analytical Thinking, Analytical Action: Using Prelab Video Demonstrations and e-Quizzes to Improve Undergraduate Preparedness for Analytical Chemistry Practical Classes

Science.gov (United States)

Jolley, Dianne F.; Wilson, Stephen R.; Kelso, Celine; O'Brien, Glennys; Mason, Claire E.

2016-01-01

This project utilizes visual and critical thinking approaches to develop a higher-education synergistic prelab training program for a large second-year undergraduate analytical chemistry class, directing more of the cognitive learning to the prelab phase. This enabled students to engage in more analytical thinking prior to engaging in the…

Simplified Entropic Model for the Evaluation of Suspended Load Concentration

Directory of Open Access Journals (Sweden)

Domenica Mirauda

2018-03-01

Full Text Available Suspended sediment concentration is a key aspect in the forecasting of river evolution dynamics, as well as in water quality assessment, evaluation of reservoir impacts, and management of water resources. The estimation of suspended load often relies on empirical models, of which efficiency is limited by their analytic structure or by the need for calibration parameters. The present work deals with a simplified fully-analytical formulation of the so-called entropic model in order to reproduce the vertical distribution of sediment concentration. The simplification consists in the leading order expansion of the generalized spatial coordinate of the entropic velocity profile that, strictly speaking, applies to the near-bed region, but that provides acceptable results also near the free surface. The proposed closed-form solution, which highlights the interplay among channel morphology, stream power, secondary flows, and suspended transport features, allows reducing the needed number of field measurements and, therefore, the time of field activities. Its accuracy and robustness were successfully tested based on the comparison with laboratory data reported in literature.

Pre-analytical sample quality: metabolite ratios as an intrinsic marker for prolonged room temperature exposure of serum samples.

Directory of Open Access Journals (Sweden)

Gabriele Anton

Full Text Available Advances in the "omics" field bring about the need for a high number of good quality samples. Many omics studies take advantage of biobanked samples to meet this need. Most of the laboratory errors occur in the pre-analytical phase. Therefore evidence-based standard operating procedures for the pre-analytical phase as well as markers to distinguish between 'good' and 'bad' quality samples taking into account the desired downstream analysis are urgently needed. We studied concentration changes of metabolites in serum samples due to pre-storage handling conditions as well as due to repeated freeze-thaw cycles. We collected fasting serum samples and subjected aliquots to up to four freeze-thaw cycles and to pre-storage handling delays of 12, 24 and 36 hours at room temperature (RT and on wet and dry ice. For each treated aliquot, we quantified 127 metabolites through a targeted metabolomics approach. We found a clear signature of degradation in samples kept at RT. Storage on wet ice led to less pronounced concentration changes. 24 metabolites showed significant concentration changes at RT. In 22 of these, changes were already visible after only 12 hours of storage delay. Especially pronounced were increases in lysophosphatidylcholines and decreases in phosphatidylcholines. We showed that the ratio between the concentrations of these molecule classes could serve as a measure to distinguish between 'good' and 'bad' quality samples in our study. In contrast, we found quite stable metabolite concentrations during up to four freeze-thaw cycles. We concluded that pre-analytical RT handling of serum samples should be strictly avoided and serum samples should always be handled on wet ice or in cooling devices after centrifugation. Moreover, serum samples should be frozen at or below -80°C as soon as possible after centrifugation.

Analytical method for urinary metabolites of the fluorine-containing pyrethroids metofluthrin, profluthrin and transfluthrin by gas chromatography/mass spectrometry.

Science.gov (United States)

Yoshida, Toshiaki

2013-01-15

An analytical method was developed for measurement of the major urinary metabolites in rats administered fluorine-containing pyrethroids (metofluthrin, profluthrin and transfluthrin) which are widely used recently as mosquito repellents or mothproof repellents. Eight metabolites, 2,3,5,6-tetrafluorobenzoic acid, 4-methyl-2,3,5,6-tetrafluorobenzoic acid, 2,2-dimethyl-3-(1-propenyl)-cyclopropanecarboxylic acid, 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid (carboxylic metabolites), 2,3,5,6-tetrafluorobenzyl alcohol, 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol, 4-methoxymethyl-2,3,5,6-tetrafluorobenzyl alcohol and 4-hydroxymethyl-2,3,5,6-tetrafluorobenzyl alcohol (alcoholic metabolites), were extracted from enzymatic hydrolyzed urine using toluene and then concentrated. After transformation to their tert-butyldimethylsilyl derivatives for carboxylic metabolites or their trimethylsilyl derivatives for alcoholic metabolites, analysis was conducted by gas chromatography/mass spectrometry in the electron impact ionization mode. The calibration curves for each metabolite were linear over the concentration range of 0-20μg/ml in urine, and the quantification limits were between 0.009 and 0.03μg/ml. The relative errors and the relative standard deviations on replicate assays were less than 6% and 5%, respectively, for all concentrations studied. The measurements were accurate and precise. The collected urine samples could be stored for up to 1 month at -20°C in a freezer. The proposed method was applied to the analysis of several urine samples collected from rats treated with these pyrethroids. Copyright © 2012 Elsevier B.V. All rights reserved.

Future analytical provision - Relocation of Sellafield Ltd Analytical Services Laboratory

International Nuclear Information System (INIS)

Newell, B.

2015-01-01

Sellafield Ltd Analytical Services provide an essential view on the environmental, safety, process and high hazard risk reduction performances by analysis of samples. It is the largest and most complex analytical services laboratory in Europe, with 150 laboratories (55 operational) and 350 staff (including 180 analysts). Sellafield Ltd Analytical Services Main Laboratory is in need of replacement. This is due to the age of the facility and changes to work streams. This relocation is an opportunity to -) design and commission bespoke MA (Medium-Active) cells, -) modify HA (High-Active) cell design to facilitate an in-cell laboratory, -) develop non-destructive techniques, -) open light building for better worker morale. The option chosen was to move the activities to the NNL Central laboratory (NNLCL) that is based at Sellafield and is the UK's flagship nuclear research and development facility. This poster gives a time schedule

Evaluation of groundwater pollution in a mining area using analytical solution: a case study of the Yimin open-pit mine in China.

Science.gov (United States)

Li, Tianxin; Li, Li; Song, Hongqing; Meng, Linglong; Zhang, Shuli; Huang, Gang

2016-01-01

This study focused on using analytical and numerical models to develop and manage groundwater resources, and predict the effects of management measurements in the groundwater system. Movement of contaminants can be studied based on groundwater flow characteristics. This study can be used for prediction of ion concentration and evaluation of groundwater pollution as the theoretical basis. The Yimin open-pit mine is located in the northern part of the Inner Mongolia Autonomous Region of China. High concentrations of iron and manganese are observed in Yimin open-pit mine because of exploitation and pumping that have increased the concentration of the ions in groundwater. In this study, iron was considered as an index of contamination, and the solute model was calibrated using concentration observations from 14 wells in 2014. The groundwater flow model and analytical solutions were used in this study to forecast pollution concentration and variation trend after calibration. With continuous pumping, contaminants will migrate, and become enriched, towards the wellhead in the flow direction. The concentration of the contaminants and the range of pollution increase with the flow rate increased. The suitable flow rate of single well should be open-pit for the standard value of pollution concentration.

Quality Indicators for Learning Analytics

Science.gov (United States)

Scheffel, Maren; Drachsler, Hendrik; Stoyanov, Slavi; Specht, Marcus

2014-01-01

This article proposes a framework of quality indicators for learning analytics that aims to standardise the evaluation of learning analytics tools and to provide a mean to capture evidence for the impact of learning analytics on educational practices in a standardised manner. The criteria of the framework and its quality indicators are based on…

The maximum ground level concentration of air pollutant and the effect of plume rise on concentration estimates

International Nuclear Information System (INIS)

Mayhoub, A.B.; Azzam, A.

1991-01-01

The emission of an air pollutant from an elevated point source according to Gaussian plume model has been presented. An elementary theoretical treatment for both the highest possible ground-level concentration and the downwind distance at which this maximum occurs for different stability classes has been constructed. The effective height release modification was taken into consideration. An illustrative case study, namely, the emission from the research reactor in Inchas, has been studied. The results of these analytical treatments and of the derived semi-empirical formulae are discussed and presented in few illustrative diagrams

Development of analytical methods for the determination of some radiologically important elements in biological materials using neutron activation analysis

International Nuclear Information System (INIS)

Dang, H.S.; Jaiswal, D.D.; Pullat, V.R.; Krishnamony, S.

1998-01-01

This paper describes the analytical methods developed for the estimation of Cs, I, Sr, Th and U in biological materials such as food and human tissues. The methods employ both, the instrumental neutron activation analysis (INAA) and radiochemical neutron activation analysis (RNAA). The adequacy of these methods to determine the concentrations of the above elements in dietary and tissue materials was also studied. The study showed that the analytical methods described in this paper are adequate for the determination of Cs, Sr, Th and U in all kinds of biological samples. In the case of I however, the method is adequate only for determining its concentration in thyroid, but needs to be modified to improve its sensitivity for the determination of I in diet samples. (author)

Gravitational settling of a highly concentrated system of solid spherical particles

Science.gov (United States)

Arkhipov, V. A.; Usanina, A. S.

2017-09-01

In the present paper, we report on the results of an experimental study of the process of gravity sedimentation of a cloud of monodispersed solid spherical particles with initial volume concentration C > 0.03, which was performed in a wide range of Reynolds numbers. An analytical estimate of the settling regimes of spherical particle clouds is presented. A new method for creating a spherical particle cloud with a high concentration of particles is proposed. A qualitative picture of the settling process of a highly concentrated particle cloud under gravity is revealed. A criterial dependence for the drag coefficient of a sedimenting spherical particle cloud as an entity is obtained.

Analytic solutions of the multigroup space-time reactor kinetics equations

International Nuclear Information System (INIS)

Lee, C.E.; Rottler, S.

1986-01-01

The development of analytical and numerical solutions to the reactor kinetics equations is reviewed. Analytic solutions of the multigroup space-time reactor kinetics equations are developed for bare and reflected slabs and spherical reactors for zero flux, zero current and extrapolated endpoint boundary conditions. The material properties of the reactors are assumed constant in space and time, but spatially-dependent source terms and initial conditions are investigated. The system of partial differential equations is reduced to a set of linear ordinary differential equations by the Laplace transform method. These equations are solved by matrix Green's functions yielding a general matrix solution for the neutron flux and precursor concentration in the Laplace transform space. The detailed pole structure of the Laplace transform matrix solutions is investigated. The temporally- and spatially-dependent solutions are determined from the inverse Laplace transform using the Cauchy residue theorem, the theorem of Frobenius, a knowledge of the detailed pole structure and matrix operators. (author)

Group Analytic Psychotherapy in Brazil.

Science.gov (United States)

Penna, Carla; Castanho, Pablo

2015-10-01

Group analytic practice in Brazil began quite early. Highly influenced by the Argentinean Pichon-Rivière, it enjoyed a major development from the 1950s to the early 1980s. Beginning in the 1970s, different factors undermined its development and eventually led to its steep decline. From the mid 1980s on, the number of people looking for either group analytic psychotherapy or group analytic training decreased considerably. Group analytic psychotherapy societies struggled to survive and most of them had to close their doors in the 1990s and the following decade. Psychiatric reform and the new public health system have stimulated a new demand for groups in Brazil. Developments in the public and not-for-profit sectors, combined with theoretical and practical research in universities, present promising new perspectives for group analytic psychotherapy in Brazil nowadays.

Applying Web Analytics to Online Finding Aids: Page Views, Pathways, and Learning about Users

Directory of Open Access Journals (Sweden)

Mark R. O'English

2011-05-01

Full Text Available Online finding aids, Internet search tools, and increased access to the World Wide Web have greatly changed how patrons find archival collections. Through analyzing eighteen months of access data collected via Web analytics tools, this article examines how patrons discover archival materials. Contrasts are drawn between access from library catalogs and from online search engines, with the latter outweighing the former by an overwhelming margin, and argues whether archival description practices should change accordingly.

The Analytical Hierarchy Process

DEFF Research Database (Denmark)

Barfod, Michael Bruhn

2007-01-01

The technical note gathers the theory behind the Analytical Hierarchy Process (AHP) and present its advantages and disadvantages in practical use.......The technical note gathers the theory behind the Analytical Hierarchy Process (AHP) and present its advantages and disadvantages in practical use....

Fetal gender prediction based on maternal plasma testosterone and insulin-like peptide 3 concentrations at midgestation and late gestation in cattle.

Science.gov (United States)

Kibushi, M; Kawate, N; Kaminogo, Y; Hannan, M A; Weerakoon, W W P N; Sakase, M; Fukushima, M; Seyama, T; Inaba, T; Tamada, H

2016-10-15

We compared maternal plasma testosterone and insulin-like peptide 3 (INSL3) concentrations between dams carrying a male versus female fetus from early to late gestation and examined the application of maternal hormonal concentrations to fetal gender prediction in dairy and beef cattle. Blood samples were collected from Holstein cows or heifers (N = 31) and Japanese Black beef cows (N = 33) at 1-month intervals at 2 to 8 months of gestation. Fetal gender was confirmed by visual observation of external genitalia of calves just after birth. Plasma testosterone and INSL3 concentrations were determined by enzyme-immunoassay. Fetal genders were judged based on cutoff values of maternal testosterone and INSL3 concentrations (male, if it was ≥ cutoff value; female, if dairy cattle (P cows (P dairy cattle (P cows (P dairy cattle at 5 and 7 months and for beef cows at 5 and 6 months, whereas those values by maternal INSL3 concentrations were 71.0% to 72.4% for the dairy cattle at 6 months and beef cows at 4 and 8 months. When multiple time points of testosterone and INSL3 concentrations at several midgestation and late gestation months were considered for fetal gender prediction, predictive values were 89.3% (5-7 months) and 85.7% to 88.0% (4-6, 8 months) for the dairy and beef breeds, respectively. Maternal testosterone and INSL3 concentrations in dams carrying a male fetus were higher than those carrying a female at midgestation and/or late gestation in Holstein and Japanese Black beef cattle. Nearly, 80% accuracy was obtained for fetal gender prediction by a single time point of maternal plasma testosterone concentrations at midgestation. Nearly 90% accuracy for the prediction was obtained when multiple time points of testosterone and INSL3 concentrations from midgestation to late gestation were considered. Copyright © 2016 Elsevier Inc. All rights reserved.

Analytical model of diffuse reflectance spectrum of skin tissue

Energy Technology Data Exchange (ETDEWEB)

Lisenko, S A; Kugeiko, M M; Firago, V A [Belarusian State University, Minsk (Belarus); Sobchuk, A N [B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk (Belarus)

2014-01-31

We have derived simple analytical expressions that enable highly accurate calculation of diffusely reflected light signals of skin in the spectral range from 450 to 800 nm at a distance from the region of delivery of exciting radiation. The expressions, taking into account the dependence of the detected signals on the refractive index, transport scattering coefficient, absorption coefficient and anisotropy factor of the medium, have been obtained in the approximation of a two-layer medium model (epidermis and dermis) for the same parameters of light scattering but different absorption coefficients of layers. Numerical experiments on the retrieval of the skin biophysical parameters from the diffuse reflectance spectra simulated by the Monte Carlo method show that commercially available fibre-optic spectrophotometers with a fixed distance between the radiation source and detector can reliably determine the concentration of bilirubin, oxy- and deoxyhaemoglobin in the dermis tissues and the tissue structure parameter characterising the size of its effective scatterers. We present the examples of quantitative analysis of the experimental data, confirming the correctness of estimates of biophysical parameters of skin using the obtained analytical expressions. (biophotonics)

An analytical protocol for the determination of total mercury concentrations in solid peat samples

DEFF Research Database (Denmark)

Roos-Barraclough, F; Givelet, N; Martinez-Cortizas, A

2002-01-01

Traditional peat sample preparation methods such as drying at high temperatures and milling may be unsuitable for Hg concentration determination in peats due to the possible presence of volatile Hg species, which could be lost during drying. Here, the effects of sample preparation and natural.......12 and 8.52 ng kg(-1) h(-1), respectively). Fertilising the peat slightly increased Hg loss (3.08 ng kg(-1) h(-1) in NPK-fertilised peat compared to 0.28 ng kg(-1) h(-1) in unfertilised peat, when averaged over all temperatures used). Homogenising samples by grinding in a machine also caused a loss of Hg....... A comparison of two Hg profiles from an Arctic peat core, measured in frozen samples and in air-dried samples, revealed that no Hg losses occurred upon air-drying. A comparison of Hg concentrations in several plant species that make up peat, showed that some species (Pinus mugo, Sphagnum recurvum...

Determination of trace elements in drinking tea by various analytical techniques

International Nuclear Information System (INIS)

Wang Chufang; Ke Chenghsiung; Yang Jenqyann

1993-01-01

Tea has been one of the most popular simulating beverages which is both heavily produced and consumed in Taiwan. The determination of minor or trace elements in drinking tea and tea leaves is therefore important for estimating the daily intake of Taiwanese considered as a safety indicator. In order to accurately and precisely determine the concentrations of trace elements in samples, several analytical methods such as AAS, NAA and ICP-AES are suggested. This paper attempts to utilize all three methods to determine the concentrations of minor or trace elements in different types of tea leaves and the extracts percolated from them. The influence of fermentation processes on the concentration levels of minor or trace elements in tea samples is investigated. Because only free metal ions are bioavailable for the human body, it is necessary to determine their concentrations in drinking tea. The dissolution of trace elements in drinking tea is therefore studied by simulating the common Chinese style of tea percolation. Concentrations of thirteen elements including Zn, Mn, Ca, Cu, Ni, Al, K, Mg, Cd, Pb, Na, Co and Sc are determined. (author) 14 refs.; 1 fig.; 6 tabs

Evaluation of factors that affect analytic variability of urine protein-to-creatinine ratio determination in dogs.

Science.gov (United States)

Rossi, Gabriele; Giori, Luca; Campagnola, Simona; Zatelli, Andrea; Zini, Eric; Paltrinieri, Saverio

2012-06-01

To determine whether preanalytic and analytic factors affect evaluation of the urinary protein-to-creatinine (UPC) ratio in dogs. 50 canine urine samples. The UPC ratio was measured to assess the intra-assay imprecision (20 measurements within a single session), the influence of predilution (1:10, 1:20, and 1:100) for urine creatinine concentration measurement, and the effect of storage at room temperature (approx 20°C), 4°C, and -20°C. The coefficient of variation at room temperature determined with the 1:20 predilution was samples with a low protein concentration or low urine specific gravity. This variability could result in misclassification of samples with UPC ratios close to the thresholds defined by the International Renal Interest Society to classify dogs as nonproteinuric (0.2), borderline proteinuric (0.21 to 0.50), or proteinuric (> 0.51). A proportional bias was found in samples prediluted 1:10, compared with samples prediluted 1:20 or 1:100. At room temperature, the UPC ratio did not significantly increase after 2 and 4 hours. After 12 hours at room temperature and at 4°C, the UPC ratio significantly increased. The UPC ratio did not significantly change during 3 months of storage at -20°C. The intra-assay precision of the UPC ratio was sufficiently low to avoid misclassification of samples, except for values close to 0.2 or 0.5. The optimal predilution ratio for urine creatinine concentration measurement was 1:20. A 1:100 predilution is recommended in samples with a urine specific gravity > 1.030. The UPC ratio must be measured as soon as samples are collected. Alternatively, samples should be immediately frozen to increase their stability and minimize the risk of misclassification of proteinuria.

Analytical model of radiation-induced precipitation at the surface of dilute binary alloy

Science.gov (United States)

Pechenkin, V. A.; Stepanov, I. A.; Konobeev, Yu. V.

2002-12-01

Growth of precipitate layer at the foil surface of an undersaturated binary alloy under uniform irradiation is treated analytically. Analytical expressions for the layer growth rate, layer thickness limit and final component concentrations in the matrix are derived for coherent and incoherent precipitate-matrix interfaces. It is shown that the high temperature limit of radiation-induced precipitation is the same for both types of interfaces, whereas layer thickness limits are different. A parabolic law of the layer growth predicted for both types of interfaces is in agreement with experimental data on γ '-phase precipitation at the surface of Ni-Si dilute alloys under ion irradiation. Effect of sputtering on the precipitation rate and on the low temperature limit of precipitation under ion irradiation is discussed.

Analytical Laboratory

Data.gov (United States)

Federal Laboratory Consortium — The Analytical Labspecializes in Oil and Hydraulic Fluid Analysis, Identification of Unknown Materials, Engineering Investigations, Qualification Testing (to support...

Learning analytics dashboard applications

NARCIS (Netherlands)

Verbert, K.; Duval, E.; Klerkx, J.; Govaerts, S.; Santos, J.L.

2013-01-01

This article introduces learning analytics dashboards that visualize learning traces for learners and teachers. We present a conceptual framework that helps to analyze learning analytics applications for these kinds of users. We then present our own work in this area and compare with 15 related

Minimization of stress concentration factor in cylindrical pressure vessels with ellipsoidal heads

International Nuclear Information System (INIS)

Magnucki, K.; Szyc, W.; Lewinski, J.

2002-01-01

The paper presents the problem of stress concentration in a cylindrical pressure vessel with ellipsoidal heads subject to internal pressure. At the line, where the ellipsoidal head is adjacent to the circular cylindrical shell, a shear force and bending moment occur, disturbing the membrane stress state in the vessel. The degree of stress concentration depends on the ratio of thicknesses of both the adjacent parts of the shells and on the relative convexity of the ellipsoidal head, with the range for radius-to-thickness ratio between 75 and 125. The stress concentration was analytically described and, afterwards, the effect of these values on the stress concentration ratio was numerically examined. Results of the analysis are shown on charts

Stability of Routine Biochemical Analytes in Whole Blood and Plasma From Lithium Heparin Gel Tubes During 6-hr Storage.

Science.gov (United States)

Monneret, Denis; Godmer, Alexandre; Le Guen, Ronan; Bravetti, Clotilde; Emeraud, Cecile; Marteau, Anthony; Alkouri, Rana; Mestari, Fouzi; Dever, Sylvie; Imbert-Bismut, Françoise; Bonnefont-Rousselot, Dominique

2016-09-01

The stability of biochemical analytes has already been investigated, but results strongly differ depending on parameters, methodologies, and sample storage times. We investigated the stability for many biochemical parameters after different storage times of both whole blood and plasma, in order to define acceptable pre- and postcentrifugation delays in hospital laboratories. Twenty-four analytes were measured (Modular® Roche analyzer) in plasma obtained from blood collected into lithium heparin gel tubes, after 2-6 hr of storage at room temperature either before (n = 28: stability in whole blood) or after (n = 21: stability in plasma) centrifugation. Variations in concentrations were expressed as mean bias from baseline, using the analytical change limit (ACL%) or the reference change value (RCV%) as acceptance limit. In tubes stored before centrifugation, mean plasma concentrations significantly decreased after 3 hr for phosphorus (-6.1% [95% CI: -7.4 to -4.7%]; ACL 4.62%) and lactate dehydrogenase (LDH; -5.7% [95% CI: -7.4 to -4.1%]; ACL 5.17%), and slightly decreased after 6 hr for potassium (-2.9% [95% CI: -5.3 to -0.5%]; ACL 4.13%). In plasma stored after centrifugation, mean concentrations decreased after 6 hr for bicarbonates (-19.7% [95% CI: -22.9 to -16.5%]; ACL 15.4%), and moderately increased after 4 hr for LDH (+6.0% [95% CI: +4.3 to +7.6%]; ACL 5.17%). Based on RCV, all the analytes can be considered stable up to 6 hr, whether before or after centrifugation. This study proposes acceptable delays for most biochemical tests on lithium heparin gel tubes arriving at the laboratory or needing to be reanalyzed. © 2016 Wiley Periodicals, Inc.

Study of temporal variation of radon concentrations in public drinking water supplies

International Nuclear Information System (INIS)

York, E.L.

1995-01-01

The Environmental Protection Agency (EPA) has proposed a Maximum Contaminant Level (MCL) for radon-222 in public drinking water supplies of 300 pCi/L. Proposed monitoring requirements include collecting quarterly grab samples for the first year, then annual samples for the remainder of the compliance cycle provided first year quarterly samples average below the MCL. The focus of this research was to study the temporal variation of groundwater radon concentrations to investigate how reliably one can predict an annual average radon concentration based on the results of grab samples. Using a open-quotes slow-flowclose quotes collection method and liquid scintillation analysis, biweekly water samples were taken from ten public water supply wells in North Carolina (6 month - 11 month sampling periods). Based on study results, temporal variations exist in groundwater radon concentrations. Statistical analysis performed on the data indicates that grab samples taken from each of the ten wells during the study period would exhibit groundwater radon concentrations within 30% of their average radon concentration

Modifications of the acidic soluble salivary proteome in human children from birth to the age of 48months investigated by a top-down HPLC-ESI-MS platform.

Science.gov (United States)

Manconi, B; Cabras, T; Pisano, E; Sanna, M T; Olianas, A; Fanos, V; Faa, G; Nemolato, S; Iavarone, F; Castagnola, M; Messana, I

2013-10-08

During the first year of life the infant oral environment undergoes dramatic changes. To investigate how the salivary proteome of human children evolves during infant development we have analyzed whole saliva of 88 children aged between 0 and 48months by a top-down platform based on RP-HPLC-ESI-MS. Children were divided according to their age into five groups (A, 0-6months, N=17; B, 7-12months, N=14; C, 13-24months, N=32; D, 25-36months, N=16; E, 37-48months, N=9). The proteins and peptides analyzed were histatins (histatin-1, histatin-3 1/24), acidic proline-rich proteins, statherin, P-B peptide, and salivary cystatins. Protein and peptide quantification based on the area of the RP-HPLC-ESI-MS extracted ion current peak evidenced that: (i) concentrations of the major salivary proteins/peptides showed a minimum in the 0-6-month-old group and increased with age; (ii) the level of histatin-1 reached a maximum in the 7-12-month-old group, a minimum in the 13-24-month-aged babies and it increased again in the 25-36-month-old group; (iii) S-type cystatins were almost undetectable in the 0-6-month-old group; (iv) P-B peptide concentration greatly increased with age; (v) histatin-3 1/24 and statherin concentrations did not show any age-related variation. The top-down proteomic approach undertaken in this work reveals that the salivary proteome of human children from birth to 48months of age shows important quantitative modifications. The concentrations of the major salivary proteins, with the exception of statherin and histatin-3 1/24, showed a minimum in the 0-6-month-old group when the expression in salivary glands is probably not fully activated. Concentrations of the salivary proteins slowly increased with age, with different trends. Only histatin-1 showed the highest concentration in the 7-12-month-old group, followed by a decrease in the 13-24-month-aged children. This particular trend could be related to the phenomenon of eruption of primary dentition. This study

Analytical solution for stress, strain and plastic instability of pressurized pipes with volumetric flaws

International Nuclear Information System (INIS)

Cunha, Sérgio B.; Netto, Theodoro A.

2012-01-01

The mechanical behavior of internally pressurized pipes with volumetric flaws is analyzed. The two possible modes of circumferentially straining the pipe wall are identified and associated to hypothesized geometries. The radial deformation that takes place by bending the pipe wall is studied by means of axisymmetric flaws and the membrane strain developed by unequal hoop deformation is analyzed with the help of narrow axial flaws. Linear elastic shell solutions for stress and strain are developed, the plastic behavior is studied and the maximum hoop stress at the flaw is related to the undamaged pipe hoop stress by means of stress concentration factors. The stress concentration factors are employed to obtain equations predicting the pressure at which the pipe fails by plastic instability for both types of flaw. These analytical solutions are validated by comparison with burst tests on 3″ diameter pipes and finite element simulations. Forty-one burst tests were carried out and two materials with very dissimilar plastic behavior, carbon steel and austenitic stainless steel, were used in the experiments. Both the analytical and the numerical predictions showed good correlation with the experimentally observed burst pressures. - Highlights: ► An analytical model for the burst of a pipe with a volumetric flaw is developed. ► Deformation, strain and stress are modeled in the elastic and plastic domains. ► The model is comprehensively validated by experiments and numerical simulations. ► The burst pressure model’s accuracy is equivalent to finite element simulations.

Information theory in analytical chemistry

National Research Council Canada - National Science Library

Eckschlager, Karel; Danzer, Klaus

1994-01-01

Contents: The aim of analytical chemistry - Basic concepts of information theory - Identification of components - Qualitative analysis - Quantitative analysis - Multicomponent analysis - Optimum analytical...

Analytic Hypoellipticity and the Treves Conjecture

Directory of Open Access Journals (Sweden)

Marco Mughetti

2016-12-01

Full Text Available We are concerned with the problem of the analytic hypoellipticity; precisely, we focus on the real analytic regularity of the solutions of sums of squares with real analytic coefficients. Treves conjecture states that an operator of this type is analytic hypoelliptic if and only if all the strata in the Poisson-Treves stratification are symplectic. We discuss a model operator, P, (firstly appeared and studied in [3] having a single symplectic stratum and prove that it is not analytic hypoelliptic. This yields a counterexample to the sufficient part of Treves conjecture; the necessary part is still an open problem.

Signals: Applying Academic Analytics

Science.gov (United States)

Arnold, Kimberly E.

2010-01-01

Academic analytics helps address the public's desire for institutional accountability with regard to student success, given the widespread concern over the cost of higher education and the difficult economic and budgetary conditions prevailing worldwide. Purdue University's Signals project applies the principles of analytics widely used in…

Comparison of soil sampling and analytical methods for asbestos at the Sumas Mountain Asbestos Site-Working towards a toolbox for better assessment.

Science.gov (United States)

Wroble, Julie; Frederick, Timothy; Frame, Alicia; Vallero, Daniel

2017-01-01

Established soil sampling methods for asbestos are inadequate to support risk assessment and risk-based decision making at Superfund sites due to difficulties in detecting asbestos at low concentrations and difficulty in extrapolating soil concentrations to air concentrations. Environmental Protection Agency (EPA)'s Office of Land and Emergency Management (OLEM) currently recommends the rigorous process of Activity Based Sampling (ABS) to characterize site exposures. The purpose of this study was to compare three soil analytical methods and two soil sampling methods to determine whether one method, or combination of methods, would yield more reliable soil asbestos data than other methods. Samples were collected using both traditional discrete ("grab") samples and incremental sampling methodology (ISM). Analyses were conducted using polarized light microscopy (PLM), transmission electron microscopy (TEM) methods or a combination of these two methods. Data show that the fluidized bed asbestos segregator (FBAS) followed by TEM analysis could detect asbestos at locations that were not detected using other analytical methods; however, this method exhibited high relative standard deviations, indicating the results may be more variable than other soil asbestos methods. The comparison of samples collected using ISM versus discrete techniques for asbestos resulted in no clear conclusions regarding preferred sampling method. However, analytical results for metals clearly showed that measured concentrations in ISM samples were less variable than discrete samples.

Analytical Chemistry and Measurement Science: (What Has DOE Done for Analytical Chemistry?)

Science.gov (United States)

Shults, W. D.

1989-04-01

Over the past forty years, analytical scientists within the DOE complex have had a tremendous impact on the field of analytical chemistry. This paper suggests six "high impact" research/development areas that either originated within or were brought to maturity within the DOE laboratories. "High impact" means they lead to new subdisciplines or to new ways of doing business.

Analytical method validation for quality control and the study of the 50 mg Propylthiouracil stability

International Nuclear Information System (INIS)

Valdes Bendoyro, Maria Olga; Garcia Penna, Caridad Margarita; Fernandez, Juan Lugones; Garcia Borges, Lisandra; Martinez Espinosa, Vivian

2010-01-01

A high-performance liquid chromatography analytical method was developed and validated for the quality control and stability studies of 50 mg Propylthiouracil tablets. Method is based in active principle separation through a 100 RP-18 RP-18 (5 μm) (250 x 4 mm) Lichrospher chromatography with UV detection to 272 nm, using a mobile phase composed by a ungaseous mixture of a 0.025 M buffer solution-monobasic potassium phosphate to pH= 4,6 ad acetonitrile in a 80:20 ratio with a flux speed of 0,5 mL/min. Analytical method was linear, precise, specific and exact in the study concentrations interval

Total antioxidative capacity and zinc concentration in dogs suffering from perianal tumours

Directory of Open Access Journals (Sweden)

Brodzki Adam

2015-09-01

Full Text Available The aim of the study was to determine total antioxidative capacity (TAC and zinc concentration in serum of dogs suffering from perianal tumours just before the start of the antihormonal treatment (AHT and one and six months later. The study was performed on 45 dogs divided into two groups: control group suffering from non-malignant tumours (N = 24 and a group with malignant neoplastic changes (N = 21. Serum TAC and zinc concentrations were measured using photometric and atomic absorption spectrophotometric methods. Six months after the start of the AHT, TAC was significantly lower by 10.6% in dogs with malignant tumours when compared to controls (P = 0.03. In the non-malignant group, serum zinc concentration was higher before the treatment than in the malignant group, while the opposite results were observed six months later (P < 0.001. In the non-malignant group, gradually decreasing values of serum zinc concentration at each stage of the investigation were observed, while the opposite results were obtained in the malignant group (P < 0.05. The obtained results indicate that malignant neoplastic process is associated with significantly reduced TAC. Determination of serum zinc concentration in dogs with non-malignant and malignant perianal tumours may have practical diagnostic and prognostic values and may serve towards increasing the effectiveness of AHT monitoring.

Analytical and statistical analysis of elemental composition of lichens

International Nuclear Information System (INIS)

Calvelo, S.; Baccala, N.; Bubach, D.; Arribere, M.A.; Riberio Guevara, S.

1997-01-01

The elemental composition of lichens from remote southern South America regions has been studied with analytical and statistical techniques to determine if the values obtained reflect species, growth forms or habitat characteristics. The enrichment factors are calculated discriminated by species and collection site and compared with data available in the literature. The elemental concentrations are standardized and compared for different species. The information was statistically processed, a cluster analysis was performed using the three first principal axes of the PCA; the three groups formed are presented. Their relationship with the species, collection sites and the lichen growth forms are interpreted. (author)

Features of changes in concentration of pituitary thyroid hormone and thyroid hormones in the blood of two-month rats with experimental hypothyroidism before and after operations with N-(2-methoxybenzoyl)-O-isopropyl-α, β-dehydrothyrozine choline ester

International Nuclear Information System (INIS)

Khachatryan, T.S.; Topuzyan, V.O.

2013-01-01

The features of pituitary thyroid hormone concentration and thyroid hormones in the blood of rats with experimental hypothyroidism before and after injections of N-(2-methoxybenzoyl)-O-isopropyl-α, β-dehydrothyrozine choline ester were investigated. A sharp increase of pituitary thyroid hormone level and a sharp decrease of the level of thyroid hormones in the blood of two-month rats with hypothyroidism have been established. Under the action of N-(2-methoxybenzoyl)-O-isopropyl--α, β-dehydrothyrozine choline ester the decrease of pituitary thyroid hormone concentration and the increase of thyroid hormones level in the rats' blood have been observed and reached their values in intact animals

Natural gas monthly

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-01-01

The Natural Gas Monthly highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the Natural Gas Monthly features articles designed to assist readers in using and interpreting natural gas information.

Serum thyroxine concentrations after radioactive iodine therapy in cats with hyperthyroidism

International Nuclear Information System (INIS)

Meric, S.M.; Hawkins, E.C.; Washabau, R.J.; Turrel, J.M.; Feldman, E.C.

1986-01-01

Thirty-one cats with hyperthyroidism were given one dose of radioactive iodine (131I) IV. Serum thyroxine (T4) concentrations were measured before treatment in all cats, at 12-hour intervals after treatment in 10 cats, and at 48-hour intervals after treatment in 21 cats. Serum T4 concentrations also were measured one month after 131 I therapy in 29 cats. Activity of 131I administered was 1.5 to 6.13 mCi, resulting in a dose of 20,000 rads to the thyroid. Serum T4 concentrations before 131 I administration were 5.3 to 51.0 micrograms/dl, with a median T4 concentration of 11.0 micrograms/dl. Serum T4 decreased most rapidly during the first 3 to 6 days after treatment. Sixteen cats (55%) had normal serum thyroxine concentrations by day 4 after 131I administration, and 23 cats (74%) were euthyroxinemic by day 8 after treatment. One month after administration of 131I, the 29 cats evaluated were clinically improved, and 24 (83%) of the 29 cats evaluated had normal serum T4 concentrations, 3 cats (10%) remained hyperthyroxinemic, and 2 cats (7%) were hypothyroxinemic. Therefore, administration of 131I was a safe and effective method to quickly decrease serum T4 concentrations in hyperthyroid cats

Analytical and environmental aspects of the flame retardant tetrabromobisphenol-A and its derivatives.

Science.gov (United States)

Covaci, Adrian; Voorspoels, Stefan; Abdallah, Mohamed Abou-Elwafa; Geens, Tinne; Harrad, Stuart; Law, Robin J

2009-01-16

The present article reviews the available literature on the analytical and environmental aspects of tetrabromobisphenol-A (TBBP-A), a currently intensively used brominated flame retardant (BFR). Analytical methods, including sample preparation, chromatographic separation, detection techniques, and quality control are discussed. An important recent development in the analysis of TBBP-A is the growing tendency for liquid chromatographic techniques. At the detection stage, mass-spectrometry is a well-established and reliable technology in the identification and quantification of TBBP-A. Although interlaboratory exercises for BFRs have grown in popularity in the last 10 years, only a few participating laboratories report concentrations for TBBP-A. Environmental levels of TBBP-A in abiotic and biotic matrices are low, probably due to the major use of TBBP-A as reactive FR. As a consequence, the expected human exposure is low. This is in agreement with the EU risk assessment that concluded that there is no risk for humans concerning TBBP-A exposure. Much less analytical and environmental information exists for the various groups of TBBP-A derivatives which are largely used as additive flame retardants.

Analytical thermal modelling of multilayered active embedded chips into high density electronic board

Directory of Open Access Journals (Sweden)

Monier-Vinard Eric

2013-01-01

Full Text Available The recent Printed Wiring Board embedding technology is an attractive packaging alternative that allows a very high degree of miniaturization by stacking multiple layers of embedded chips. This disruptive technology will further increase the thermal management challenges by concentrating heat dissipation at the heart of the organic substrate structure. In order to allow the electronic designer to early analyze the limits of the power dissipation, depending on the embedded chip location inside the board, as well as the thermal interactions with other buried chips or surface mounted electronic components, an analytical thermal modelling approach was established. The presented work describes the comparison of the analytical model results with the numerical models of various embedded chips configurations. The thermal behaviour predictions of the analytical model, found to be within ±10% of relative error, demonstrate its relevance for modelling high density electronic board. Besides the approach promotes a practical solution to study the potential gain to conduct a part of heat flow from the components towards a set of localized cooled board pads.

Business intelligence making decisions through data analytics

CERN Document Server

Surma, Jerzy

2014-01-01

This book is about using business intelligence as a management information system for supporting managerial decision making. It concentrates primarily on practical business issues and demonstrates how to apply data warehousing and data analytics to support business decision making. This book progresses through a logical sequence, starting with data model infrastructure, then data preparation, followed by data analysis, integration, knowledge discovery, and finally the actual use of discovered knowledge. All examples are based on the most recent achievements in business intelligence. Finally this book outlines an overview of a methodology that takes into account the complexity of developing applications in an integrated business intelligence environment. This book is written for managers, business consultants, and undergraduate and postgraduates students in business administration.

Organizational Models for Big Data and Analytics

Directory of Open Access Journals (Sweden)

Robert L. Grossman

2014-04-01

Full Text Available In this article, we introduce a framework for determining how analytics capability should be distributed within an organization. Our framework stresses the importance of building a critical mass of analytics staff, centralizing or decentralizing the analytics staff to support business processes, and establishing an analytics governance structure to ensure that analytics processes are supported by the organization as a whole.

Leptin administration to overweight and obese subjects for 6 months increases free leptin concentrations but does not alter circulating hormones of the thyroid and IGF axes during weight loss induced by a mild hypocaloric diet.

Science.gov (United States)

Shetty, Greeshma K; Matarese, Giuseppe; Magkos, Faidon; Moon, Hyun-Seuk; Liu, Xiaowen; Brennan, Aoife M; Mylvaganam, Geetha; Sykoutri, Despina; Depaoli, Alex M; Mantzoros, Christos S

2011-08-01

Short-term energy deprivation reduces leptin concentrations and alters the levels of circulating hormones of the hypothalamic-pituitary-peripheral axis in lean subjects. Whether the reduction in leptin concentration during long-term weight loss in obese individuals is linked to the same neuroendocrine changes seen in lean, leptin-sensitive subjects remains to be fully clarified. In this study, 24 overweight and obese adults (16 women and eight men; body mass index (BMI): 27.5-38.0 kg/m(2)) were prescribed a hypocaloric diet (-500 kcal/day) and were randomized to receive recombinant methionyl leptin (n=18, metreleptin, 10 mg/day self-injected s.c.) or placebo (n=6, same volume and time as metreleptin) for 6 months. Metreleptin administration did not affect weight loss beyond that induced by hypocaloric diet alone (P for interaction=0.341) but increased the serum concentrations of total leptin by six- to eight-fold (Phypocaloric diet in overweight and obese subjects.

Effect of 6-8 weeks of oral ursodeoxycholic acid administration on serum concentrations of fasting and postprandial bile acids and biochemical analytes in healthy dogs.

Science.gov (United States)

Deitz, Krysta L; Makielski, Kelly M; Williams, Jackie M; Lin, Hui; Morrison, Jo Ann

2015-09-01

Ursodeoxycholic acid (UDCA) is commonly used for the treatment of hepatobiliary disease. UDCA is a bile acid that can be detected in the bile acid assay. Its effect on biochemical analytes is unknown. The aim of this study was to determine the effect of 6-8 weeks of UDCA administration on fasting and postprandial concentrations of serum bile acids (SBA), cholesterol, triglycerides, bilirubin, and liver enzyme activities in healthy dogs. Twenty healthy dogs received UDCA for 6-8 weeks. CBC, biochemistry profile, urinalysis, fasting and postprandial SBA, and hepatobiliary ultrasound examination were performed prior to starting UDCA (timepoint 0) and after 6-8 weeks of therapy, while animals were still receiving UDCA (timepoint 1). Timepoint 0 and timepoint 1 values were compared with a paired t-test. SBA were remeasured 72 hours after UDCA discontinuation. Only mean fasting SBA at timepoint 1 increased significantly (P = .03) from timepoint 0 (2.26 μmol/L at time 0 and 3.81 μmol/L at time 1) but were not elevated above the normal reference interval (0-9 μmol/L). Two dogs had timepoint 1 fasting SBA above the reference interval (10 and 11.7 μmol/L). One dog had timepoint 1 postprandial SBA above the reference interval at 20.1 μmol/L (reference interval 0-17 μmol/L). Repeat SBA 72 hours after UDCA discontinuation were normal. Long-term administration of UDCA to healthy dogs may increase fasting SBA above pretreatment values (typically within the reference interval). Long-term administration of UDCA to healthy dogs does not alter liver enzyme activities, and bilirubin, cholesterol, or triglyceride concentrations. © 2015 American Society for Veterinary Clinical Pathology.

An analytical model for a low-level uranium detector for soil analysis

International Nuclear Information System (INIS)

Fortkamp, J.C.

1994-01-01

This thesis addresses the need for a field useable means of measuring the concentration of 238 U in soil. An analytical model was developed and refined based on a method conceived by David Holcomb. The method utilizes the high energy β of 234m Pa, a daughter in secular equilibrium with 238 U. A subtraction of the contribution of any other high energy β emitters present is done using a gamma coincidence system. The main component of the detector system defined was a 30cmx60cmx0.2cm plastic scintillating sheet. It was also shown that with proper calibration, the subtraction process will give accurate measurements of the 238 U concentration

Atorvastatin reduces malondialdehyde concentrations in patients with polycystic ovary syndrome.

Science.gov (United States)

Sathyapalan, Thozhukat; Shepherd, John; Coady, Anne-Marie; Kilpatrick, Eric S; Atkin, Stephen L

2012-11-01

It has been shown that there is an increase in oxidative stress in polycystic ovary syndrome (PCOS). Statins are considered to have a pleiotropic effect other than their lipid-lowering effect. These effects may be mediated in part by reducing oxidative stress. This randomized, double-blind, placebo-controlled study was conducted to assess the effect of atorvastatin on serum malondialdehyde (MDA) concentrations as a marker of oxidative stress in patients with PCOS. Forty medication-naïve patients with PCOS were randomized to either atorvastatin 20 mg daily or placebo for 3 months. A 3-month extension study for both groups of patients was undertaken with metformin 1500 mg daily after completing initial 3 months of atorvastatin or placebo. There was a significant decrease of MDA concentrations with atorvastatin [mean (sem)] [0.29 (0.04) vs. 0.25 (0.02) μmol/liter; P polycystic ovary syndrome that was independently predicted by changes in testosterone, 25OHD, and high-sensitivity C-reactive protein.

Analytical use of electron accelerators

International Nuclear Information System (INIS)

Kapitsa, S.P.; Chapyzhnikov, B.A.; Firsov, V.I.; Samosyuk, V.N.; Tsipenyuk, Y.M.

1985-01-01

After detailed investigation the authors conclude that the newest electron accelerators provide good scope for gamma activation and also for producing neutrons for neutron activation. These accelerators are simpler and safer than reactors, and one can provide fairly homogeneous irradiation of substantial volumes, and the determination speed and sensitivity then constitute the main advantages. The limits of detection and the reproducibility are sufficient to handle a wide range of tasks. Analysts at present face a wide range of unlikely extreme problems, while the selectivity provides exceptional analysis facilities. However, the record examples are not to be taken as exceptions, since activation analysis based on electron accelerators opens up essentially universal scope for analyzing all elements at the concentrations and accuracies currently involved, which will involve its extensive use in analytical practice in the foreseeable future. The authors indicate that the recognition of these possibilities governs the general use of these methods and the employment of current efficient fast-electron sources to implement them

Accurate computations of monthly average daily extraterrestrial irradiation and the maximum possible sunshine duration

International Nuclear Information System (INIS)

Jain, P.C.

1985-12-01

The monthly average daily values of the extraterrestrial irradiation on a horizontal plane and the maximum possible sunshine duration are two important parameters that are frequently needed in various solar energy applications. These are generally calculated by solar scientists and engineers each time they are needed and often by using the approximate short-cut methods. Using the accurate analytical expressions developed by Spencer for the declination and the eccentricity correction factor, computations for these parameters have been made for all the latitude values from 90 deg. N to 90 deg. S at intervals of 1 deg. and are presented in a convenient tabular form. Monthly average daily values of the maximum possible sunshine duration as recorded on a Campbell Stoke's sunshine recorder are also computed and presented. These tables would avoid the need for repetitive and approximate calculations and serve as a useful ready reference for providing accurate values to the solar energy scientists and engineers

Analytical spectroscopy. Analytical Chemistry Symposia Series, Volume 19

International Nuclear Information System (INIS)

Lyon, W.S.

1984-01-01

This book contains papers covering several fields in analytical chemistry including lasers, mass spectrometry, inductively coupled plasma, activation analysis and emission spectroscopy. Separate abstracting and indexing was done for 64 papers in this book

Bayesian Estimation of the Active Concentration and Affinity Constants Using Surface Plasmon Resonance Technology.

Directory of Open Access Journals (Sweden)

Feng Feng

Full Text Available Surface plasmon resonance (SPR has previously been employed to measure the active concentration of analyte in addition to the kinetic rate constants in molecular binding reactions. Those approaches, however, have a few restrictions. In this work, a Bayesian approach is developed to determine both active concentration and affinity constants using SPR technology. With the appropriate prior probabilities on the parameters and a derived likelihood function, a Markov Chain Monte Carlo (MCMC algorithm is applied to compute the posterior probability densities of both the active concentration and kinetic rate constants based on the collected SPR data. Compared with previous approaches, ours exploits information from the duration of the process in its entirety, including both association and dissociation phases, under partial mass transport conditions; do not depend on calibration data; multiple injections of analyte at varying flow rates are not necessary. Finally the method is validated by analyzing both simulated and experimental datasets. A software package implementing our approach is developed with a user-friendly interface and made freely available.

Monthly Weather Review

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Supplements to the Monthly Weather Review publication. The Weather Bureau published the Monthly weather review Supplement irregularly from 1914 to 1949. The...

Quine's "Strictly Vegetarian" Analyticity

NARCIS (Netherlands)

Decock, L.B.

2017-01-01

I analyze Quine’s later writings on analyticity from a linguistic point of view. In Word and Object Quine made room for a “strictly vegetarian” notion of analyticity. In later years, he developed this notion into two more precise notions, which I have coined “stimulus analyticity” and “behaviorist

Large-scale data analytics

CERN Document Server

Gkoulalas-Divanis, Aris

2014-01-01

Provides cutting-edge research in large-scale data analytics from diverse scientific areas Surveys varied subject areas and reports on individual results of research in the field Shares many tips and insights into large-scale data analytics from authors and editors with long-term experience and specialization in the field

Platelet concentration in platelet concentrates and periodontal regeneration-unscrambling the ambiguity

Directory of Open Access Journals (Sweden)

A Suchetha

2015-01-01

Full Text Available Context: Platelet-rich-plasma (PRP and Platelet-rich-fibrin (PRF are extensively used autologous platelet concentrates in periodontal regeneration, and PRF has a better efficacy as compared to PRP. The rationale for this difference has often been attributed to the difference in the structure of the fibrin matrix. However, the effect of concentration of platelets on the regenerative potential of these concentrates is obscure. Aims: The study was conducted to evaluate and compare, clinically and radiographically, the efficacy of PRF and PRP in the treatment of periodontal endosseous defects and to assess the effect of platelet concentration on periodontal regeneration. Materials and Methods: Twenty intrabony defects were selected and divided into two groups randomly by the coin toss method. Group I received PRP and Group II subjects were treated with PRF. The platelet counts in PRP and PRF were analyzed. Clinical and radiological parameters were assessed at baseline and 3, 6, and 9 months postoperatively. Statistical Analysis: Kruskal–Wallis Chi-square test, Wilcoxon signed rank test, t-test, and Spearman's rank correlation were used for statistical analysis of data. Results: There was statistically significant improvement in all the parameters in the two groups except in relation to gingival recession. There was a statistically significant difference between the platelet count in Group I and Group II (P = 0.002. Conclusion: PRP and PRF appear to have nearly comparable effects in terms of periodontal regeneration. The concentration of platelets appears to play a paradoxical role in regeneration. The regenerative potential of platelets appears to be optimal within a limited range.

CANSAR. Analytical irradiation for PCI analysis

International Nuclear Information System (INIS)

Bruet, M.; Lemaignan, C.

1984-01-01

The aim of ''CANSAR'' analytical irradiation is to evaluate the various mechanisms expected to be active during PCI failures (local concentration of fission products, fuel expansion, stress concentration induced by fuel fragment relocation, etc.). Two identical test pins, similar to classical PWR pins, but shorter, will be power-ramped in parallel. They will be filled with fuel pellets machined in various ways in order to simulate pellet fracture, relocation and preferential fission product migration path. One pin is highly instrumented with fission gas analysis, centre-line temperature and strain gauges on the cladding. The other can be unloaded between the pile cycles to perform other measurements such as diameter change, eddy currents, hot cell γ scanning. The gauges are necessary to obtain valuable information on cladding stresses. However, they induce significant modification of the thermal and mechanical behaviour of the cladding. Extensive finite element computation has been undertaken to estimate the temperature shift and the cladding reinforcement due to the gauges. Details of this work performed to design and implement the experiment will be presented. This included, in particular, high precision machining of UO 2 sectors to obtain ''precracked'' pellets and computation of the thermo-mechanical behaviour of the cladding with the gauges. (author)

The National Shipbuilding Research Program. Development of a Quick TBT Analytical Method

Science.gov (United States)

2000-08-16

Development of a Quick TBT Analytical Method 09/25/2000 Page 3 of 38 Executive Summary Concern about the toxic effect of tributyltin have caused the...Antifouling Paints on the Environment Tributyl tin ( TBT ) has been shown to be highly toxic to certain aquatic organisms at concentrations measured in the...paints, developed in the 1960s, contains the organotin tributyltin ( TBT ), which has been proven to cause deformations in oysters and sex changes in

Social media analytics and research testbed (SMART: Exploring spatiotemporal patterns of human dynamics with geo-targeted social media messages

Directory of Open Access Journals (Sweden)

Jiue-An Yang

2016-06-01

Full Text Available The multilevel model of meme diffusion conceptualizes how mediated messages diffuse over time and space. As a pilot application of implementing the meme diffusion, we developed the social media analytics and research testbed to monitor Twitter messages and track the diffusion of information in and across different cities and geographic regions. Social media analytics and research testbed is an online geo-targeted search and analytics tool, including an automatic data processing procedure at the backend and an interactive frontend user interface. Social media analytics and research testbed is initially designed to facilitate (1 searching and geo-locating tweet topics and terms in different cities and geographic regions; (2 filtering noise from raw data (such as removing redundant retweets and using machine learning methods to improve precision; (3 analyzing social media data from a spatiotemporal perspective; and (4 visualizing social media data in diagnostic ways (such as weekly and monthly trends, trend maps, top media, top retweets, top mentions, or top hashtags. Social media analytics and research testbed provides researchers and domain experts with a tool that can efficiently facilitate the refinement, formalization, and testing of research hypotheses or questions. Three case studies (flu outbreaks, Ebola epidemic, and marijuana legalization are introduced to illustrate how the predictions of meme diffusion can be examined and to demonstrate the potentials and key functions of social media analytics and research testbed.

Improved nutritional status in elderly patients 6 months after stroke

DEFF Research Database (Denmark)

Brynningsen, P K; Damsgaard, Else Marie; Husted, Steen

2007-01-01

INTRODUCTION: Nutritional status among stroke patients has received limited attention despite the fact, that it may have an influence on clinical outcome. Previous studies have estimated that 15-20 % of patients suffer from malnutrition in the acute phase of stroke, but so far no studies have...... focused on the late rehabilitation phase after stroke in the patients own home, where the attention on nutrition may be reduced. AIMS: To determine the prevalence of malnutrition during 6 months of stroke rehabilitation, and to investigate the association between nutritional status, functional recovery...... and 6 months. Nutritional status was evaluated by body weight, body mass index (BMI), mid upper arm circumference (MAC), triceps skinfold thickness (TSF) and serum concentrations of albumin and transferrin. Malnutrition was defined if the patients had 2 or more abnormal nutritional variables. RESULTS...

Determination of Mercury in Milk by Cold Vapor Atomic Fluorescence: A Green Analytical Chemistry Laboratory Experiment

Science.gov (United States)

Armenta, Sergio; de la Guardia, Miguel

2011-01-01

Green analytical chemistry principles were introduced to undergraduate students in a laboratory experiment focused on determining the mercury concentration in cow and goat milk. In addition to traditional goals, such as accuracy, precision, sensitivity, and limits of detection in method selection and development, attention was paid to the…

Application of FEM analytical method for hydrogen migration behaviour in Zirconium alloys

Energy Technology Data Exchange (ETDEWEB)

Arioka, K; Ohta, H [Takasago Research and Development Center, Mitsubishi Heavy Industries Ltd, Hyogo-ken (Japan)

1997-02-01

It is well recognized that the hydriding behaviours of Zirconium alloys are very significant problems as a safety issues. Also, it is well known that the diffusion of hydrogen in Zirconium alloys are affected not only by concentration but also temperature gradient. But in actual component, especially heat transfer tube such as fuel rod, we can not avoid the temperature gradient in some degree. So, it is very useful to develop the computer code which can analyze the hydrogen diffusion and precipitation behaviours under temperature gradient as a function of the structure of fuel rod. For this objective, we have developed the computer code for hydrogen migration behaviour using FEM analytical methods. So, following items are presented and discussed. Analytical method and conditions; correlation between the computed and test results; application to designing studies. (author). 8 refs, 4 figs, 2 tabs.

Evaluation of the analytic performance of laboratories: inter-laboratorial study of the spectroscopy of atomic absorption

International Nuclear Information System (INIS)

Wong Wong, S. M.

1996-01-01

The author made an inter-laboratorial study, with the participation of 18 national laboratories, that have spectrophotometer of atomic absorption. To evaluate the methods of analysis of lead, sodium, potasium, calcium, magnesium, zinc, copper, manganese, and iron, in the ambit of mg/l. The samples, distributed in four rounds to the laboratories, were prepared from primary patterns, deionized and distilled water. The study evaluated the homogeneity and stability, and verified its concentration, using as a reference method, the spectrometry method of Inductively Coupled Plasma emission (1CP). To obtain the characteristics of analytic performance, it applied the norm ASTM E 691. To evaluated the analytic performance, it used harmonized protocol of the International Union of Pure and applied chemistry (IUPAC). The study obtained the 29% of the laboratories had a satisfactory analytic performance, 9% had a questionable performance and 62% made an unsatisfactory analytic performance, according to the IUPAC norm. The results of the values of the characteristic performance method, show that there is no intercomparability between the laboratories, which is attributed to the different methodologies of analysis. (S. Grainger)

[The Hypo Ionic Protein Profile (HIPP). Laboratory analytical evaluation in Complementary and Alternative Medicine].

Science.gov (United States)

Berth, M; Stalpaert, M; Bosmans, E

2008-01-01

The hypo ionic protein profile (HIPP) is a test based on the reticulo-endothelial index of Sandor. We evaluated the analytical performance of this test by comparing the obtained data in the HIPP to the concentration of some frequently measured specific serum proteins. The alfa euglobulin zone mainly comprises of ceruloplasmin, complement factor 3, apolipoprotein B and haptoglobin. The beta and gamma euglobulin zone reflect the concentration of the immunoglobulins. Since these proteins cannot be distinguished from each other, the diagnostic value of the HIPP will be limited. The HIPP is an outdated and aspecific assay for protein measurements.

Analytical methods for toxic gases from thermal degradation of polymers

Science.gov (United States)

Hsu, M.-T. S.

1977-01-01

Toxic gases evolved from the thermal oxidative degradation of synthetic or natural polymers in small laboratory chambers or in large scale fire tests are measured by several different analytical methods. Gas detector tubes are used for fast on-site detection of suspect toxic gases. The infrared spectroscopic method is an excellent qualitative and quantitative analysis for some toxic gases. Permanent gases such as carbon monoxide, carbon dioxide, methane and ethylene, can be quantitatively determined by gas chromatography. Highly toxic and corrosive gases such as nitrogen oxides, hydrogen cyanide, hydrogen fluoride, hydrogen chloride and sulfur dioxide should be passed into a scrubbing solution for subsequent analysis by either specific ion electrodes or spectrophotometric methods. Low-concentration toxic organic vapors can be concentrated in a cold trap and then analyzed by gas chromatography and mass spectrometry. The limitations of different methods are discussed.

Validation of an analytical method applicable to study of 1 mg/mL oral Risperidone solution stability

International Nuclear Information System (INIS)

Abreu Alvarez, Maikel; Garcia Penna, Caridad Margarita; Martinez Miranda, Lissette

2010-01-01

A validated analytical method by high-performance liquid chromatography (HPLC) was applicable to study of 1 mg/mL Risperidone oral solution stability. The above method was linear, accurate, specific and exact. A stability study of the 1 mg/mL Risperidone oral solution was developed determining its expiry date. The shelf life study was conducted for 24 months at room temperature; whereas the accelerated stability study was conducted with product under influence of humidity and temperature; analysis was made during 3 months. Formula fulfilled the quality specifications described in Pharmacopeia. The results of stability according to shelf life after 24 months showed that the product maintains the parameters determining its quality during this time and in accelerated studies there was not significant degradation (p> 0.05) in the product. Under mentioned conditions expiry date was of 2 years

SIMULTANEOUS ABSORPTION AND DESORPTION WITH REVERSIBLE 1ST-ORDER CHEMICAL-REACTION - ANALYTICAL SOLUTION AND NEGATIVE ENHANCEMENT FACTORS

NARCIS (Netherlands)

WINKELMAN, JGM; BEENACKERS, AACM

The problem of ps absorption accompanied by a first-order reversible reaction, producing a volatile reaction product, is considered. A general analytical solution is developed for the film model, resulting in explicit relations for the concentration profiles in the film and for the mass transfer

Analytical solutions for non-linear conversion of a porous solid particle in a gas–I. Isothermal conversion

NARCIS (Netherlands)

Brem, Gerrit; Brouwers, J.J.H.

1990-01-01

Analytical description are presented for non-linear heterogeneous conversion of a porous solid particle reacting with a surrounding gas. Account has been taken of a reaction rate of general order with respect to gas concentration, intrinsic reaction surface area and pore diffusion, which change with