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Sample records for abnormal tracer uptake

  1. Myocardial uptake of a bone tracer associated with hypercalcemia

    SciTech Connect

    Atkins, H.L.; Oster, Z.H.

    1984-11-01

    A patient with end-stage renal disease and hypercalcemia was referred for a radionuclide bone imaging study. Deposition of Tc-99m hydroxymethylenediphosphonate was apparent in the lungs and myocardium as well as in the skeleton. Renal uptake was also noted, despite anuria. Computed tomography demonstrated nephrocalcinosis but no myocardial calcification. The cause of myocardial uptake of tracer is unknown. Amyloidosis is suggested as a possibility but is not validated in this case.

  2. Gastrointestinal Stromal Tumor Showing Intense Tracer Uptake on PSMA PET/CT.

    PubMed

    Noto, Benjamin; Weckesser, Matthias; Buerke, Boris; Pixberg, Michaela; Avramovic, Nemanja

    2017-03-01

    A 70-year-old man with suspected prostate cancer was referred for Ga-PSMA-HBED-CC PET/CT (short PSMA PET/CT) for staging of tumor extent. Apart from vivid tracer uptake in the prostate gland and osseous metastasis, PSMA PET/CT revealed a large soft tissue mass with calcifications in the left upper abdomen showing intense tracer uptake. Histologic examination revealed the mass to be a gastrointestinal stromal tumor.

  3. Glucose Metabolism in Sediments of a Eutrophic Lake: Tracer Analysis of Uptake and Product Formation †

    PubMed Central

    King, Gary M.; Klug, M. J.

    1982-01-01

    The uptake of glucose and the formation of end products from glucose catabolism have been measured for sediments of eutrophic Wintergreen Lake with a combination of tritiated and 14C-labeled tracers. Time course analyses of the loss of [3H]glucose from sediments were used to establish rate constants for glucose uptake at natural substrate concentrations. Turnover times from these analyses were about 1 min for littoral and profundal sediments. No seasonal or site differences were noted in turnover times. Time course analyses of [U-14C]glucose uptake and 14C-labeled end product formation indicated that glucose mass flow could not be calculated from end product formation since the specific activity of added [14C]glucose was significantly diluted by pools of intracellular glucose and glucose metabolites. Mass flow could only be accurately estimated by use of rates of uptake from tracer studies. Intermediate fermentation end products included acetate (71%), propionate (15%), lactate (9%), and only minor amounts of butyrates or valerates. Addition of H2 to sediments resulted in greater production of lactate (28%) and decreased formation of acetate (50%), but did not affect glucose turnover. Depth profiles of glucose uptake indicated that rates of uptake decreased with depth over the 0- to 18-cm interval and that glucose uptake accounted for 30 to 40% of methanogenesis in profundal sediments. PMID:16346148

  4. Hotspot quantification of myocardial focal tracer uptake from molecular targeted SPECT/CT images: experimental validation

    NASA Astrophysics Data System (ADS)

    Liu, Yi-Hwa; Sahul, Zakir; Weyman, Christopher A.; Ryder, William J.; Dione, Donald P.; Dobrucki, Lawrence W.; Mekkaoui, Choukri; Brennan, Matthew P.; Hu, Xiaoyue; Hawley, Christi; Sinusas, Albert J.

    2008-03-01

    We have developed a new single photon emission computerized tomography (SPECT) hotspot quantification method incorporating extra cardiac activity correction and hotspot normal limit estimation. The method was validated for estimation accuracy of myocardial tracer focal uptake in a chronic canine model of myocardial infarction (MI). Dogs (n = 4) at 2 weeks post MI were injected with Tl-201 and a Tc-99m-labeled hotspot tracer targeted at matrix metalloproteinases (MMPs). An external point source filled with Tc-99m was used for a reference of absolute radioactivity. Dual-isotope (Tc-99m/Tl-201) SPECT images were acquired simultaneously followed by an X-ray CT acquisition. Dogs were sacrificed after imaging for myocardial gamma well counting. Images were reconstructed with CT-based attenuation correction (AC) and without AC (NAC) and were quantified using our quantification method. Normal limits for myocardial hotspot uptake were estimated based on 3 different schemes: maximum entropy, meansquared-error minimization (MSEM) and global minimization. Absolute myocardial hotspot uptake was quantified from SPECT images using the normal limits and compared with well-counted radioactivity on a segment-by-segment basis (n = 12 segments/dog). Radioactivity was expressed as % injected dose (%ID). There was an excellent correlation (r = 0.78-0.92) between the estimated activity (%ID) derived using the SPECT quantitative approach and well-counting, independent of AC. However, SPECT quantification without AC resulted in the significant underestimation of radioactivity. Quantification using SPECT with AC and the MSEM normal limit yielded the best results compared with well-counting. In conclusion, focal myocardial "hotspot" uptake of a targeted radiotracer can be accurately quantified in vivo using a method that incorporates SPECT imaging with AC, an external reference, background scatter compensation, and a suitable normal limit. This hybrid SPECT/CT approach allows for the serial

  5. {sup 41}Ca as a tracer for calcium uptake and deposition in heart tissue during ischemia and reperfusion

    SciTech Connect

    Southon, J.R.; Bishop, M.S.; Kost, G.J.

    1993-09-17

    We have developed techniques and are commencing experiments using enriched {sup 41}Ca as a tracer in isolated rabbit heart preparations. The aims of the study are to measure calcium uptake and deposition in response to cardiac ischemia and reperfusion, and to investigate events and mechanism leading to irreversible myocyte injury.

  6. Extracellular domain shedding influences specific tumor uptake and organ distribution of the EGFR PET tracer 89Zr-imgatuzumab

    PubMed Central

    Pool, Martin; Kol, Arjan; Lub-de Hooge, Marjolijn N.; Gerdes, Christian A.; de Jong, Steven; de Vries, Elisabeth G.E.; Terwisscha van Scheltinga, Anton G.T.

    2016-01-01

    Preclinical positron emission tomography (PET) imaging revealed a mismatch between in vivo epidermal growth factor receptor (EGFR) expression and EGFR antibody tracer tumor uptake. Shed EGFR ectodomain (sEGFR), which is present in cancer patient sera, can potentially bind tracer and therefore influence tracer kinetics. To optimize EGFR-PET, we examined the influence of sEGFR levels on tracer kinetics and tumor uptake of EGFR monoclonal antibody 89Zr-imgatuzumab in varying xenograft models. Human cancer cell lines A431 (EGFR overexpressing, epidermoid), A549 and H441 (both EGFR medium expressing, non-small cell lung cancer) were xenografted in mice. Xenografted mice received 10, 25 or 160 μg 89Zr-imgatuzumab, co-injected with equal doses 111In-IgG control. MicroPET scans were made 24, 72 and 144 h post injection, followed by biodistribution analysis. sEGFR levels in liver and plasma samples were determined by ELISA. 89Zr-imgatuzumab uptake in A431 tumors was highest (29.8 ± 5.4 %ID/g) in the 160 μg dose group. Contrary, highest uptake in A549 and H441 tumors was found at the lowest (10 μg) 89Zr-imgatuzumab dose. High 89Zr-imgatuzumab liver accumulation was found in A431 xenografted mice, which decreased with antibody dose increments. 89Zr-imgatuzumab liver uptake in A549 and H441 xenografted mice was low at all doses. sEGFR levels in liver and plasma of A431 bearing mice were up to 1000-fold higher than levels found in A549, H441 and non-tumor xenografted mice. 89Zr-imgatuzumab effectively visualizes EGFR-expressing tumors. High sEGFR levels can redirect 89Zr-imgatuzumab to the liver, in which case tumor visualization can be improved by increasing tracer antibody dose. PMID:27602494

  7. A Dual Tracer PET-MRI Protocol for the Quantitative Measure of Regional Brain Energy Substrates Uptake in the Rat

    PubMed Central

    Roy, Maggie; Nugent, Scott; Tremblay, Sébastien; Descoteaux, Maxime; Beaudoin, Jean-François; Tremblay, Luc; Lecomte, Roger; Cunnane, Stephen C

    2013-01-01

    We present a method for comparing the uptake of the brain's two key energy substrates: glucose and ketones (acetoacetate [AcAc] in this case) in the rat. The developed method is a small-animal positron emission tomography (PET) protocol, in which 11C-AcAc and 18F-fluorodeoxyglucose (18F-FDG) are injected sequentially in each animal. This dual tracer PET acquisition is possible because of the short half-life of 11C (20.4 min). The rats also undergo a magnetic resonance imaging (MRI) acquisition seven days before the PET protocol. Prior to image analysis, PET and MRI images are coregistered to allow the measurement of regional cerebral uptake (cortex, hippocampus, striatum, and cerebellum). A quantitative measure of 11C-AcAc and 18F-FDG brain uptake (cerebral metabolic rate; μmol/100 g/min) is determined by kinetic modeling using the image-derived input function (IDIF) method. Our new dual tracer PET protocol is robust and flexible; the two tracers used can be replaced by different radiotracers to evaluate other processes in the brain. Moreover, our protocol is applicable to the study of brain fuel supply in multiple conditions such as normal aging and neurodegenerative pathologies such as Alzheimer's and Parkinson's diseases. PMID:24430432

  8. A hydrological tracer study of water uptake depth in a Scots pine forest under two different water regimes.

    PubMed

    Plamboeck, A H; Grip, H; Nygren, U

    1999-05-01

    Little is known about the vertical distribution of water uptake by trees under different water supply regimes, the subject of this study, conducted in a Scots pine stand on sandy loam in northern Sweden. The objective was to determine the water uptake distribution in pines under two different water regimes, desiccation (no precipitation) and irrigation (2 mm day(-1) in July and 1 mm day(-1) in August), and to relate the uptake to water content, root and soil texture distributions. The natural (18)O gradient in soil water was exploited, in combination with two added tracers, (2)H at 10 cm and (3)H at 20 cm depth. Extraction of xylem sap and water from the soil profile then enabled evaluation of relative water uptake from four different soil depths (humus layer, 0-10, 10-25 and 25-55 cm) in each of two 50-m(2) plots per treatment. In addition, water content, root biomass and soil texture were determined. There were differences in vertical water uptake distribution between treatments. In July, the pines at the irrigated and desiccated plots took up 50% and 30%, respectively, of their water from the upper layers, down to 25 cm depth. In August, the pines on the irrigated plots took up a greater proportion of their water from layers below 25 cm deep than they did in July. In a linear regression, the mean hydraulic conductivity for each mineral soil horizon explained a large part of the variation in relative water uptake. No systematic variation in the residual water uptake correlated to the root distribution. It was therefore concluded that the distribution of water uptake by the pines at Åheden was not a function of root density in the mineral soil, but was largely determined by the unsaturated hydraulic conductivity.

  9. Design and utilisation of protocols to characterise dynamic PET uptake of two tracers using basis pursuit.

    PubMed

    Bell, Christopher Michael; Puttick, Simon; Rose, Stephen; Smith, Jye; Thomas, Paul; Dowson, Nicholas

    2017-04-04

    Imaging using more than one biological process using PET could be of great utility, but despite previously proposed approaches to dual-tracer imaging, it is seldom performed. The alternative of performing multiple scans is often infeasible for clinical practice or even in research studies. Dual-tracer PET scanning allows for multiple PET radiotracers to be imaged within the same imaging session. In this paper we describe our approach to utilise the basis pursuit method to aid in the R2.9 design of dual-tracer PET imaging experiments, and later in separation of the signals. The advantage of this approach is that it does not require a compartment model architecture to be specified or even that both signals are distinguishable in all cases. This means the R2.16 method for separating dual-tracer signals can be used for many feasible and useful combinations of biology or radiotracer, once an appropriate scanning protocol has been decided upon. Following a demonstration in separating the signals from two consecutively injected radionuclides in a controlled experiment, phantom and list-mode mouse experiments demonstrated the ability to test the R2.13feasibility of dual-tracer imaging protocols for multiple injection delays. Increases in variances predicted for kinetic macro-parameters VD and KI in brain and tumoral tissue were obtained when R2.14 separating the synthetically combined data. R2.2 These experiments confirmed previous work using other approaches that injections delays of 10-20 minutes ensured increases in variance were kept minimal for the test tracers used. On this basis, an actual dual-tracer experiment using a 20-minute delay was performed using these radio tracers, with the kinetic parameters (VD and KI) extracted for each tracer in agreement with the literature. This R2.4, 2.8 study supports previous work that dual-tracer PET imaging can be accomplished provided certain constraints are adhered to. The utilisation of basis pursuit techniques, with its

  10. Plant uptake of cations under nutrient limitation: An environmental tracer study using Ca/Sr and K/Rb ratios

    NASA Astrophysics Data System (ADS)

    Shi, Z.; Keller, C. K.; Stacks, D.; Grant, M.; Harsh, J. B.; Letourneau, M.; Gill, R. A.; Balogh-Brunstad, Z.; Thomashow, L.; Dohnalkova, A.

    2012-12-01

    Vascular plant growth builds soils and ecosystem nutrient capital by sequestering and partitioning atmospheric CO2 into organic matter and continental runoff and driving terrestrial water and energy balances. Plant root-system functions, e.g. nutrient mobilization and uptake, are altered by environmental stress. However, the stress-response relationships are poorly understood. Chemical tracers have potential for assessing contributions of nutrients from various nutrient pools. Our objective is to quantitatively study how varying degrees of nutrient limitation (and corresponding needs to extract base cations from mineral sources) influence Ca and K uptake functions in a plant-root-mineral system. We are studying plant-driven mineral weathering in column experiments with red pine (Pinus resinosa) seedlings. The columns contain quartz sand amended with anorthite and biotite that constitute the sole mineral sources of Ca and K. These minerals also contain known amounts of Sr and Rb, which exhibit chemical behavior similar to Ca and K, respectively. The solution source of Ca and K was varied by adding 0% (no dissolved Ca and K), 10%, 30%, or 100% of a full strength Ca and K nutrient solution through irrigation water in which both Sr and Rb concentrations were negligible. Selected columns were destructively sampled at 3, 6 and 9 months to harvest biomass and measure plant uptake of cations. We used Ca/Sr and K/Rb ratio results to estimate the contributions of Ca and K from mineral and solution sources. For the 0% nutrient treatment, the Ca/Sr and K/Rb ratios in total biomass at 3 months, compared with those in the mineral phases, suggested preferential uptake of Ca and K over Sr and Rb, respectively, and allowed us to determine uptake discrimination factors for both cations. The K/Rb ratios in total biomass increased with greater K availability in the solution source, as expected, but Ca/Sr ratios did not show any dependence on Ca availability in the solution source

  11. Single photon emission computed tomography in Alzheimer's disease. Abnormal iofetamine I 123 uptake reflects dementia severity

    SciTech Connect

    Johnson, K.A.; Holman, B.L.; Mueller, S.P.; Rosen, T.J.; English, R.; Nagel, J.S.; Growdon, J.H.

    1988-04-01

    To determine whether abnormalities in regional cerebral functional activity estimated by iofetamine hydrochloride I 123 and single photon emission computed tomography can be detected in mild or moderate as well as severe cases of Alzheimer's disease (AD), we performed iofetamine I 123-single photon emission computed tomography in 37 patients with probable AD (nine patients with mild, 18 patients with moderate, and ten patients with severe dementia) and nine age-matched control subjects. Iofetamine I 123 uptake was measured in right and left frontal, temporal, parietal, and occipital cortices. Mean (right and left) iofetamine I 123 activity was lowest in the parietal region of patients with AD and was significantly reduced in the other three regions compared with control subjects. Only in the parietal region was lower relative iofetamine I 123 activity associated with an impaired level of patient function and with cognitive deficit.

  12. Tracer study of oxygen and hydrogen uptake by Mg alloys in air with water vapor

    DOE PAGES

    Brady, M. P.; Fayek, M.; Meyer, H. M.; ...

    2015-05-15

    We studied the pure oxidation of Mg, Mg–3Al–1Zn (AZ31B), and Mg–1Zn–0.25Zr–<0.5Nd (ZE10A) at 85 °C in humid air using sequential exposures with H218O and D216O for water vapor. Incorporation of 18O in the hydroxide/oxide films indicated that oxygen from water vapor participated in the reaction. Moreover, penetration of hydrogen into the underlying metal was observed, particularly for the Zr- and Nd-containing ZE10A. Isotopic tracer profiles suggested a complex mixed inward/outward film growth mechanism.

  13. Tracer study of oxygen and hydrogen uptake by Mg alloys in air with water vapor

    SciTech Connect

    Brady, M. P.; Fayek, M.; Meyer, H. M.; Leonard, D. N.; Elsentriecy, H. H.; Unocic, K. A.; Anovitz, L. M.; Cakmak, E.; Keiser, J. R.; Song, G. L.; Davis, B.

    2015-05-15

    We studied the pure oxidation of Mg, Mg–3Al–1Zn (AZ31B), and Mg–1Zn–0.25Zr–<0.5Nd (ZE10A) at 85 °C in humid air using sequential exposures with H218O and D216O for water vapor. Incorporation of 18O in the hydroxide/oxide films indicated that oxygen from water vapor participated in the reaction. Moreover, penetration of hydrogen into the underlying metal was observed, particularly for the Zr- and Nd-containing ZE10A. Isotopic tracer profiles suggested a complex mixed inward/outward film growth mechanism.

  14. Can fog contribute to the nutrition of Chamaecyparis obtusa var. formosana? Uptake of a fog solute tracer into foliage and transport to roots.

    PubMed

    Lai, I-Ling; Schroeder, Walter H; Wu, Jiunn-Tzong; Kuo-Huang, Ling-Long; Mohl, Carola; Chou, Chang-Hung

    2007-07-01

    Yellow cypress (Chamaecyparis obtusa (Siebold & Zucc.) Endl. var. formosana (Hayata) Rehder) is the predominant tree species of Taiwan's nutrient-poor, mountain fog forests. Little is known about the potential contribution of solute uptake from fog to the overall nutrition of these trees. Shoots of yellow cypress seedlings were misted with artificial fog containing the tracer rubidium (Rb) in laboratory and field experiments to determine if there is solute uptake from the fog. After misting shoots for six weeks, substantial amounts of tracer were detected in unexposed roots by inductively coupled plasma mass spectroscopy bulk analysis. Possible routes of entry were examined by element imaging with energy dispersive X-ray analysis. Direct uptake of the tracer into leaves across the cuticle and epidermis was small, excluding this as the major uptake path. Accumulations of Rb were found on leaf surfaces along the edges of the leaves. The almost daily changes in fog coverage and air humidity may enhance the accumulation of fog solutes at leaf edges. Accumulation of Rb was also found in narrow clefts between opposite leaves and between the outermost and underlying alternating stacked leaves. The clefts provide a direct passage from the leaf surface to the space beneath the imbricate leaves and the underlying alternate leaves, possibly facilitating solute uptake from fog, which in turn may contribute to the nutrition of yellow cypress.

  15. Uptake of stormwater nitrogen in bioretention systems demonstrated from 15N tracer techniques

    NASA Astrophysics Data System (ADS)

    Houdeshel, D.; Hultine, K. R.; Pomeroy, C. A.

    2012-12-01

    Bioretention stormwater management systems are engineered ecosystems that capture urban stormwater in order to reduce the harmful effects of stormwater pollution on receiving waters. Bioretention systems have been shown to be effective at reducing the volume of runoff, and thereby reduce the nutrient loading to receiving waters from urban areas. However, little work has been done to evaluate the treatment processes that are responsible for reductions in effluent nitrogen (N). We hypothesize that the pulses of inorganic nitrogen associated with urban runoff events are captured in the plat tissues within these systems and not adsorbed to the soil media, thus creating a long-term, sustainable treatment approach to reducing the total nutrient loading to receiving waters. Nitrogen treatment performance was tested on two bioretention systems in Salt Lake City, UT: 1) an upland native community that does not require irrigation in semi-arid climates, and 2) a wetland community that requires 250 l of daily irrigation to offset the relatively high evaporative demand in the region. Each cell is sized to treat a 2.5 cm storm from a 140 m2 impervious surface: the area of the bioretention system is 10 m2. To test the N removal performance of each system, runoff events were simulated to represent an average precipitation regime using a synthetic stormwater blend starting in January, 2012. Effluent was collected from an underdrain and analyzed for total nitrogen (TN); mass removal was calculated for each month by subtracting the TN mass added to the garden minus the TN mass that flowed out of the garden. To test the hypothesis that plants assimilate stormwater N, 4 g of 100 atom% 15N NH4NO3 tracer was used as the N source in the synthetic stormwater during the first 2,000 l synthetic storm event in May. This isotopic label was calculated to enrich the total N pool of each garden to 100‰ 15N/14Nair. New growth was harvested from each plant in both cells and analyzed for 15N

  16. Continuous infusion of tracer norepinephrine may miscalculate unidirectional nerve uptake of norepinephrine in humans

    SciTech Connect

    Henriksen, J.H.; Christensen, N.J.; Ring-Larsen, H. )

    1989-08-01

    In order to evaluate uptake kinetics of norepinephrine (NE) in different tissues, a catheterization study was performed in control subjects (n = 6) and patients with enhanced sympathetic nervous activity (cirrhosis, n = 12) during constant intravenous infusion of L(3H)norepinephrine ((3H)NE) for 75 minutes. In spite of a higher NE spillover from kidneys in patients compared with controls (82 vs. 49 ng/min, p less than 0.01), renal extraction ratios of (3H)NE were similar in the two groups (0.33 vs. 0.32, NS), and no significant change was observed during the time of infusion. In contrast, liver-intestine extraction ratios of (3H)NE decreased significantly and equally with infusion time in patients (from 0.57 to 0.44, p less than 0.01) and controls (from 0.59 to 0.46, p less than 0.01). This was observed despite the fact that spillover of NE from this vascular bed was observed only in patients with cirrhosis and not in controls (41 vs. -5 ng/min, p less than 0.02). In the lower limb, net release of NE was similar in patients and controls, and extraction ratios of (3H)NE decreased almost equally with infusion time (from 0.35 to 0.30, p less than 0.01 and from 0.40 to 0.24, p less than 0.1, respectively). Whole-body clearance of (3H)NE decreased over time in patients (-6%, p less than 0.01) and controls (-20%, p less than 0.01), but significant difference was not observed between the groups. We conclude that failure to attain a steady state with respect to (3H)NE removal was demonstrated in areas of large tissue volume relative to blood flow.

  17. [Comparative investigations of osteotropic radionucleides. IV. The dynamics of uptake in normal and abnormal bone (author's transl)].

    PubMed

    Creutzig, H; Gerdts, K G; Creutzig, A

    1977-03-01

    The dynamics of uptake of osteotropic radionucleides in normal and abnormal bone were studied by means of sequential and functional scans. Various phosphate and phosphonate complexes were compared in vivo and in vitro. Only phosphonates were considered as suitable for bone scanning. In normal bones in beagles, radioactivity after HEDP fell to 65% after two hours, but was 105% with 18F. In relation to healing fractures, the curves differ quantitatively and qualitatively. In this situation, functional curves derived from dynamic scans provide a better parallel with histological findings than does static scintigraphy with an uptake quotient. Sequential and functional scanning are able to document the therapeutic effect of irradiation of bone metastases.

  18. Ammonium and nitrate uptake lengths in a small forested stream determined by {sup 15}N tracer and short-term nutrient enrichment experiments

    SciTech Connect

    Mulholland, P.J.; Tank, J.L.; Sanzone, D.M.; Webster, J.R.; Wollheim, W.; Peterson, B.J.; Meyer, J.L.

    1998-11-01

    Nutrient cycling is an important characteristic of all ecosystems, including streams. Nutrients often limit the growth rates of stream algae and heterotrophic microbes and the decomposition rate of allochthonous organic matter. Nutrient uptake (S{sub W}), defined as the mean distance traveled by a nutrient atom dissolved in stream water before uptake by biota is often used as an index of nutrient cycling in streams. It is often overlooked, however, that S{sub W} is not a measure of nutrient uptake rate per se, but rather a measure of the efficiency with which a stream utilizes the available nutrient supply. The ideal method for measuring S{sub W} involves short-term addition of a nutrient tracer. Regulatory constraints often preclude use of nutrient radiotracers in field studies and methodological difficulties and high analytical costs have previously hindered the use of stable isotope nutrient tracers (e.g., {sup 15}N). Short-term nutrient enrichments are an alternative to nutrient tracer additions for measuring S{sub W}.

  19. Mild experimental ketosis increases brain uptake of 11C-acetoacetate and 18F-fluorodeoxyglucose: a dual-tracer PET imaging study in rats.

    PubMed

    Pifferi, Fabien; Tremblay, Sébastien; Croteau, Etienne; Fortier, Mélanie; Tremblay-Mercier, Jennifer; Lecomte, Roger; Cunnane, Stephen C

    2011-03-01

    Brain glucose and ketone uptake was investigated in Fisher rats subjected to mild experimental ketonemia induced by a ketogenic diet (KD) or by 48 hours fasting (F). Two tracers were used, (11)C-acetoacetate ((11)C-AcAc) for ketones and (18)F-fluorodeoxyglucose for glucose, in a dual-tracer format for each animal. Thus, each animal was its own control, starting first on the normal diet, then undergoing 48 hours F, followed by 2 weeks on the KD. In separate rats on the same diet conditions, expression of the transporters of glucose and ketones (glucose transporter 1 (GLUT1) and monocarboxylic acid transporter (MCT1)) was measured in brain microvessel preparations. Compared to controls, uptake of (11)C-AcAc increased more than 2-fold while on the KD or after 48 hours F (P < 0.05). Similar trends were observed for (18)FDG uptake with a 1.9-2.6 times increase on the KD and F, respectively (P < 0.05). Compared to controls, MCT1 expression increased 2-fold on the KD (P < 0.05) but did not change during F. No significant difference was observed across groups for GLUT1 expression. Significant differences across the three groups were observed for plasma beta-hydroxybutyrate (beta-HB), AcAc, glucose, triglycerides, glycerol, and cholesterol (P < 0.05), but no significant differences were observed for free fatty acids, insulin, or lactate. Although the mechanism by which mild ketonemia increases brain glucose uptake remains unclear, the KD clearly increased both the blood-brain barrier expression of MCT1 and stimulated brain (11)C-AcAc uptake. The present dual-tracer positron emission tomography approach may be particularly interesting in neurodegenerative pathologies such as Alzheimer's disease where brain energy supply appears to decline critically.

  20. Microwave irradiation of rats at 2. 45 GHz activates pinocytotic-like uptake of tracer by capillary endothelial cells of cerebral cortex

    SciTech Connect

    Neubauer, C.; Phelan, A.M.; Kues, H.; Lange, D.G. )

    1990-01-01

    Far-field exposures of male albino rats to 2.45-GHz microwaves (10-microseconds pulses, 100 pps) at a low average power density (10 mW/cm2; SAR approximately 2 W/kg) and short durations (30-120 min) resulted in increased uptakes of tracer through the blood-brain barrier (BBB). The uptake of systemically administered rhodamine-ferritin complex by capillary endothelial cells (CECs) of the cerebral cortex was dependent on power density and on duration of exposure. At 5 mW/cm2, for example, a 15-min exposure had no effect. Near-complete blockade of uptake resulted when rats were treated before exposure to microwaves with a single dose of colchicine, which inhibits microtubular function. A pinocytotic-like mechanism is presumed responsible for the microwave-induced increase in BBB permeability.

  1. Effects of CT-based attenuation correction of rat microSPECT images on relative myocardial perfusion and quantitative tracer uptake

    SciTech Connect

    Strydhorst, Jared H. Ruddy, Terrence D.; Wells, R. Glenn

    2015-04-15

    Purpose: Our goal in this work was to investigate the impact of CT-based attenuation correction on measurements of rat myocardial perfusion with {sup 99m}Tc and {sup 201}Tl single photon emission computed tomography (SPECT). Methods: Eight male Sprague-Dawley rats were injected with {sup 99m}Tc-tetrofosmin and scanned in a small animal pinhole SPECT/CT scanner. Scans were repeated weekly over a period of 5 weeks. Eight additional rats were injected with {sup 201}Tl and also scanned following a similar protocol. The images were reconstructed with and without attenuation correction, and the relative perfusion was analyzed with the commercial cardiac analysis software. The absolute uptake of {sup 99m}Tc in the heart was also quantified with and without attenuation correction. Results: For {sup 99m}Tc imaging, relative segmental perfusion changed by up to +2.1%/−1.8% as a result of attenuation correction. Relative changes of +3.6%/−1.0% were observed for the {sup 201}Tl images. Interscan and inter-rat reproducibilities of relative segmental perfusion were 2.7% and 3.9%, respectively, for the uncorrected {sup 99m}Tc scans, and 3.6% and 4.3%, respectively, for the {sup 201}Tl scans, and were not significantly affected by attenuation correction for either tracer. Attenuation correction also significantly increased the measured absolute uptake of tetrofosmin and significantly altered the relationship between the rat weight and tracer uptake. Conclusions: Our results show that attenuation correction has a small but statistically significant impact on the relative perfusion measurements in some segments of the heart and does not adversely affect reproducibility. Attenuation correction had a small but statistically significant impact on measured absolute tracer uptake.

  2. Uptake of HNO3 to deliquescent sea-salt particles: a study using the short-lived radioactive isotope tracer 13N

    NASA Astrophysics Data System (ADS)

    Guimbaud, C.; Arens, F.; Gutzwiller, L.; Gäggeler, H. W.; Ammann, M.

    2002-10-01

    The uptake of HNO3 to deliquescent airborne sea-salt particles (RH = 55%, P = 760 torr, T = 300 K) at concentrations from 2 to 575 ppbv is measured in an aerosol flow tube using 13N as a tracer. Small particles ( 70 nm diameter) are used in order to minimize the effect of diffusion in the gas phase on the mass transfer. Below 100 ppbv, an uptake coefficient (gupt) of 0.50 ± 0.20 is derived. At higher concentrations, the uptake coefficient decreases along with the consumption of aerosol chloride. Data interpretation is further supported by using the North American Aerosol Inorganics Model (AIM), which predicts the aqueous phase activities of ions and the gas-phase partial pressures of H2O, HNO3, and HCl at equilibrium for the NaCl/HNO3/H2O system. These simulations show that the low concentration data are obtained far from equilibrium, which implies that the uptake coefficient derived is equal to the mass accommodation coefficient under these conditions. The observed uptake coefficient can serve as input to modeling studies of atmospheric sea-salt aerosol chemistry. The main sea-salt aerosol burden in the marine atmosphere is represented by coarse mode particles (> 1 µm diameter). This implies that diffusion in the gas-phase is the limiting step to HNO3 uptake until the sea-salt has been completely processed.

  3. Incidental abnormal FDG uptake in the prostate on 18-fluoro-2-deoxyglucose positron emission tomography-computed tomography scans.

    PubMed

    Kang, Pil Moon; Seo, Won Ik; Lee, Sun Seong; Bae, Sang Kyun; Kwak, Ho Sup; Min, Kweonsik; Kim, Wansuk; Kang, Dong Il

    2014-01-01

    18-fluoro-2-deoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) scans are commonly used for the staging and restaging of various malignancies, such as head and neck, breast, colorectal and gynecological cancers. However, the value of FDG PET/CT for detecting prostate cancer is unknown. The aim of this study was to evaluate the clinical value of incidental prostate 18F-FDG uptake on PET/CT scans. We reviewed 18F-FDG PET/CT scan reports from September 2009 to September 2013, and selected cases that reported focal/diffuse FDG uptake in the prostate. We analyzed the correlation between 18F-FDG PET/CT scan findings and data collected during evaluations such as serum prostate-specific antigen (PSA) levels, digital rectal examination (DRE), transrectal ultrasound (TRUS), and/or biopsy to confirm prostate cancer. Of a total of 18,393 cases, 106 (0.6%) exhibited abnormal hypermetabolism in the prostate. Additional evaluations were performed in 66 patients. Serum PSA levels were not significantly correlated with maximum standardized uptake values (SUVmax) in all patients (rho 0.483, p=0.132). Prostate biopsies were performed in 15 patients, and prostate cancer was confirmed in 11. The median serum PSA level was 4.8 (0.55-7.06) ng/mL and 127.4 (1.06-495) ng/mL in the benign and prostate cancer groups, respectively. The median SUVmax was higher in the prostate cancer group (mean 10.1, range 3.8-24.5) than in the benign group (mean 4.3, range 3.1-8.8), but the difference was not statistically significant (p=0.078). There was no significant correlation between SUVmax and serum PSA, prostatic volume, or Gleason score. 18F-FDG PET/CT scans did not reliably differentiate malignant or benign from abnormal uptake lesions in the prostate, and routine prostate biopsy was not usually recommended in patients with abnormal FDG uptake. Nevertheless, patients with incidental prostate uptake on 18F-FDG PET/ CT scans should not be ignored and should be undergo

  4. Congenital lymphatic hypoplasia in unilateral lower limb with abnormal technetium-99m sulphur colloid uptake in both breasts

    PubMed Central

    Padma, Subramanyam; Sundaram, Palaniswamy Shanmuga

    2014-01-01

    We present a patient with Meige like lymphedema (left lower limb hypoplasia) with asymptomatic minimal accumulation of Technetium-99m sulfur colloid in bilateral breasts. We attribute the possible pathology to accumulation of interstitial fluid in hypoplastic left lower limb leading to dilatation of the remaining outflow tracts and valvular incompetence. This may be causing reversal of flow from subcutaneous tissues into the dermal plexus involving the breast. Other possibilities include formation of spontaneous lymphovenous shunt or lymphatic intercommunication at lower trunk level as a result of increased pressure leading to minimal lymph accumulation in breasts. Later a mammogram was performed which was found to be normal. MR also confirmed no cisterna chyli abnormalities or aberrant lymphatic channels in lower thorax region that may be the explanation for the abnormal sulphur colloid uptake in both breasts. PMID:25400372

  5. Abnormal lung gallium-67 uptake preceding pulmonary physiologic impairment in an asymptomatic patient with Pneumocystis carinii pneumonia

    SciTech Connect

    Reiss, T.F.; Golden, J. )

    1990-05-01

    Pneumocystis carinii pneumonia was suggested by a diffuse, bilateral pulmonary uptake of gallium-67 in an asymptomatic, homosexual male with the antibody to the immunodeficiency virus (HIV) who was undergoing staging evaluation for lymphoma clinically localized to a left inguinal lymph node. Chest radiograph and pulmonary function evaluation, including lung volumes, diffusing capacity and arterial blood gases, were within normal limits. Bronchoalveolar lavage revealed Pneumocystis carinii organisms. In this asymptomatic, HIV-positive patient, active alveolar infection, evidenced by abnormal gallium-67 scanning, predated pulmonary physiologic abnormalities. This observation raises questions concerning the natural history of this disease process and the specificity of physiologic tests for excluding disease. It also has implications for the treatment of neoplasia in the HIV-positive patient population.

  6. The reproducibility of striatal uptake data obtained with positron emission tomography and fluorine-18-L-6-fluorodopa tracer in non-human primates

    SciTech Connect

    Pate, B.D.; Snow, B.J.; Hewitt, K.A.; Morrison, K.S.; Ruth, T.J.; Calne, D.B. )

    1991-06-01

    Cynomolgus and rhesus monkeys have been studied via PET with (18F)-L-6 fluorodopa tracer. Striatal fluorodopa uptake rate constants have been derived by graphical analysis of transaxial slice images centered on the striata. The differences between pairs of values of the rate constant, obtained from two scans on the same monkey separated by two weeks or more, exhibited a relative standard deviation of 34.4%. If the two scans were conducted one immediately after the other, with the position of the monkey undisturbed, the standard deviation was reduced to 14.0%. The utility of this technique was demonstrated by comparing the effects on the scans of halothane and pentobarbital anesthesia and by the administration of NSD 1015, a peripheral and central inhibitor of L-aromatic amino-acid decarboxylase, between back-to-back scans. With NSD 1015, the fluorodopa uptake constant was reduced by an average of 76.0%.

  7. Is integrated 18F-FDG PET/MRI superior to 18F-FDG PET/CT in the differentiation of incidental tracer uptake in the head and neck area?

    PubMed Central

    Schaarschmidt, Benedikt Michael; Gomez, Benedikt; Buchbender, Christian; Grueneisen, Johannes; Nensa, Felix; Sawicki, Lino Morris; Ruhlmann, Verena; Wetter, Axel; Antoch, Gerald; Heusch, Philipp

    2017-01-01

    PURPOSE We aimed to investigate the accuracy of 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI) compared with contrast-enhanced 18F-FDG PET/computed tomography (PET/CT) for the characterization of incidental tracer uptake in examinations of the head and neck. METHODS A retrospective analysis of 81 oncologic patients who underwent contrast-enhanced 18F-FDG PET/CT and subsequent PET/MRI was performed by two readers for incidental tracer uptake. In a consensus reading, discrepancies were resolved. Each finding was either characterized as most likely benign, most likely malignant, or indeterminate. Using all available clinical information including results from histopathologic sampling and follow-up examinations, an expert reader classified each finding as benign or malignant. McNemar’s test was used to compare the performance of both imaging modalities in characterizing incidental tracer uptake. RESULTS Forty-six lesions were detected by both modalities. On PET/CT, 27 lesions were classified as most likely benign, one as most likely malignant, and 18 as indeterminate; on PET/MRI, 31 lesions were classified as most likely benign, one lesion as most likely malignant, and 14 as indeterminate. Forty-three lesions were benign and one lesion was malignant according to the reference standard. In two lesions, a definite diagnosis was not possible. McNemar’s test detected no differences concerning the correct classification of incidental tracer uptake between PET/CT and PET/MRI (P = 0.125). CONCLUSION In examinations of the head and neck area, incidental tracer uptake cannot be classified more accurately by PET/MRI than by PET/CT. PMID:28089955

  8. Radium uptake during barite recrystallization at 23 ± 2 °C as a function of solution composition: An experimental 133Ba and 226Ra tracer study

    NASA Astrophysics Data System (ADS)

    Curti, E.; Fujiwara, K.; Iijima, K.; Tits, J.; Cuesta, C.; Kitamura, A.; Glaus, M. A.; Müller, W.

    2010-06-01

    High-purity synthetic barite powder was added to pure water or aqueous solutions of soluble salts (BaCl 2, Na 2SO 4, NaCl and NaHCO 3) at 23 ± 2 °C and atmospheric pressure. After a short pre-equilibration time (4 h) the suspensions were spiked either with 133Ba or 226Ra and reacted under constant agitation during 120-406 days. The pH values ranged from 4 to 8 and solid to liquid (S/L) ratios varied from 0.01 to 5 g/l. The uptake of the radiotracers by barite was monitored through repeated sampling of the aqueous solutions and radiometric analysis. For both 133Ba and 226Ra, our data consistently showed a continuous, slow decrease of radioactivity in the aqueous phase. Mass balance calculations indicated that the removal of 133Ba activity from aqueous solution cannot be explained by surface adsorption only, as it largely exceeded the 100% monolayer coverage limit. This result was a strong argument in favor of recrystallization (driven by a dissolution-precipitation mechanism) as the main uptake mechanism. Because complete isotopic equilibration between aqueous solution and barite was approached or even reached in some experiments, we concluded that during the reaction all or substantial fractions of the initial solid had been replaced by newly formed barite. The 133Ba data could be successfully fitted assuming constant recrystallization rates and homogeneous distribution of the tracer into the newly formed barite. An alternative model based on partial equilibrium of 133Ba with the mineral surface (without internal isotopic equilibration of the solid) could not reproduce the measured activity data, unless multistage recrystallization kinetics was assumed. Calculated recrystallization rates in the salt solutions ranged from 2.8 × 10 -11 to 1.9 × 10 -10 mol m -2 s -1 (2.4-16 μmol m -2 d -1), with no specific trend related to solution composition. For the suspensions prepared in pure water, significantly higher rates (˜5.7 × 10 -10 mol m -2 s -1 or ˜49 μmol m

  9. Uptake and Degradation of Protease-Sensitive and -Resistant Forms of Abnormal Human Prion Protein Aggregates by Human Astrocytes

    PubMed Central

    Choi, Young Pyo; Head, Mark W.; Ironside, James W.; Priola, Suzette A.

    2015-01-01

    Sporadic Creutzfeldt-Jakob disease is the most common of the human prion diseases, a group of rare, transmissible, and fatal neurologic diseases associated with the accumulation of an abnormal form (PrPSc) of the host prion protein. In sporadic Creutzfeldt-Jakob disease, disease-associated PrPSc is present not only as an aggregated, protease-resistant form but also as an aggregated protease-sensitive form (sPrPSc). Although evidence suggests that sPrPSc may play a role in prion pathogenesis, little is known about how it interacts with cells during prion infection. Here, we show that protease-sensitive abnormal PrP aggregates derived from patients with sporadic Creutzfeldt-Jakob disease are taken up and degraded by immortalized human astrocytes similarly to abnormal PrP aggregates that are resistant to proteases. Our data suggest that relative proteinase K resistance does not significantly influence the astrocyte's ability to degrade PrPSc. Furthermore, the cell does not appear to distinguish between sPrPSc and protease-resistant PrPSc, suggesting that sPrPSc could contribute to prion infection. PMID:25280631

  10. Comparison of concentration pulse and tracer pulse chromatography: experimental determination of eluent uptake by bridged-ethylene hybrid ultra high performance liquid chromatography packings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excess volume isotherms of acetonitrile and methanol sorbed on a C18 BEH UHPLC packing were determined over a range of pressure, temperature, flow rate and eluent composition. The isotherm measurements were carried out by two independent experimental methods, viz., concentration pulse and tracer pul...

  11. 18F-Sodium Fluoride PET-CT Hybrid Imaging of the Lumbar Facet Joints: Tracer Uptake and Degree of Correlation to CT-graded Arthropathy

    PubMed Central

    Mabray, Marc C.; Brus-Ramer, Marcel; Behr, Spencer C.; Pampaloni, Miguel H.; Majumdar, Sharmila; Dillon, William P.; Talbott, Jason F.

    2016-01-01

    We aim to evaluate 18F-NaF uptake by facet joints with hybrid PET-CT technique. Specifically, we evaluate NaF uptake in the facet joints of the lower lumbar spine, and correlate with the morphologic grade of facet arthropathy on CT. 30 consecutive patients who underwent standard vertex to toes NaF PET-CT for re-staging of primary neoplastic disease without measurable or documented bony metastases were identified. Maximum (SUVmax) and average (SUVavg) standardized uptake values were calculated for each L3-4, L4-5, and L5-S1 facet joint (n = 180) and normalized to average uptake in the non-diseased femur. A Pathria grade (0-3) was assigned to each facet based upon the CT morphology. Spearman's rank correlation was performed for normalized SUVmax and SUVavg with Pathria grade. ANOVA was performed with Tukey-Kramer pairwise tests to evaluate differences in uptake between Pathria groups. Facet normalized SUVmax (r = 0.31, P < 0.001) and SUVavg (r = 0.28, P < 0.001) demonstrated a mild positive correlation with CT Pathria grade. There was a wide range of uptake values within each Pathria grade subgroup with statistically significant differences in uptake only between Pathria grade 3 as compared to grades 0, 1, and 2. In conclusion, NaF uptake and morphologic changes of the facet joint on CT are weakly correlated. Physiologic information provided by NaF uptake is often discrepant with structural findings on CT suggesting NaF PET may supplement conventional structural imaging for identification of pain generating facet joints. Prospective investigation into the relationship of facet joint NaF uptake with pain and response to pain interventions is warranted. PMID:27134557

  12. Red blood cells of sickle cell disease patients exhibit abnormally high abundance of N-methyl D-aspartate receptors mediating excessive calcium uptake.

    PubMed

    Hänggi, Pascal; Makhro, Asya; Gassmann, Max; Schmugge, Markus; Goede, Jeroen S; Speer, Oliver; Bogdanova, Anna

    2014-10-01

    Recently we showed that N-methyl D-aspartate receptors (NMDARs) are expressed in erythroid precursors (EPCs) and present in the circulating red blood cells (RBCs) of healthy humans, regulating intracellular Ca(2+) in these cells. This study focuses on investigating the possible role of NMDARs in abnormally high Ca(2+) permeability in the RBCs of patients with sickle cell disease (SCD). Protein levels of the NMDAR subunits in the EPCs of SCD patients did not differ from those in EPCs of healthy humans. However, the number and activity of the NMDARs in circulating SCD-RBCs was substantially up-regulated, being particularly high during haemolytic crises. The number of active NMDARs correlated negatively with haematocrit and haemoglobin levels in the blood of SCD patients. Calcium uptake via these non-selective cation channels was induced by RBC treatment with glycine, glutamate and homocysteine and was facilitated by de-oxygenation of SCD-RBCs. Oxidative stress and RBC dehydration followed receptor stimulation and Ca(2+) uptake. Inhibition of the NMDARs with an antagonist memantine caused re-hydration and largely prevented hypoxia-induced sickling. The EPCs of SCD patients showed higher tolerance to memantine than those of healthy subjects. Consequently, NMDARs in the RBCs of SCD patients appear to be an attractive target for pharmacological intervention.

  13. A dual-tracer study of extrastriatal 6-[18F]fluoro-m-tyrosine and 6-[18F]-fluoro-L-dopa uptake in Parkinson's disease.

    PubMed

    Li, Clarence T; Palotti, Matthew; Holden, James E; Oh, Jen; Okonkwo, Ozioma; Christian, Bradley T; Bendlin, Barbara B; Buyan-Dent, Laura; Harding, Sandra J; Stone, Charles K; DeJesus, Onofre T; Nickles, Robert J; Gallagher, Catherine L

    2014-08-01

    6-[(18)F]-Fluoro-L-dopa (FDOPA) has been widely used as a biomarker for catecholamine synthesis, storage, and metabolism--its intense uptake in the striatum, and fainter uptake in other brain regions, is correlated with the symptoms and pathophysiology of Parkinson's disease (PD). 6-[(18)F]fluoro-m-tyrosine (FMT), which also targets L-amino acid decarboxylase, has potential advantages over FDOPA as a radiotracer because it does not form catechol-O-methyltransferase (COMT) metabolites. The purpose of the present study was to compare the regional distribution of these radiotracers in the brains of PD patients. Fifteen Parkinson's patients were studied with FMT and FDOPA positron emission tomography (PET) as well as high-resolution structural magnetic resonance imaging (MRI). MRI's were automatically parcellated into neuroanatomical regions of interest (ROIs) in Freesurfer (http://surfer.nmr.mgh.harvard.edu); region-specific uptake rate constants (Kocc) were generated from coregistered PET using a Patlak graphical approach. The essential findings were as follows: (1) regional Kocc were highly correlated between the radiotracers and in agreement with a previous FDOPA studies that used different ROI selection techniques; (2) FMT Kocc were higher in extrastriatal regions of relatively large uptake such as amygdala, pallidum, brainstem, hippocampus, entorhinal cortex, and thalamus, whereas cortical Kocc were similar between radiotracers; (3) while subcortical uptake of both radiotracers was related to disease duration and severity, cortical uptake was not. These results suggest that FMT may have advantages for examining pathologic changes within allocortical loop structures, which may contribute to cognitive and emotional symptoms of PD.

  14. (68)Ga-DOTATOC PET and gene expression profile in patients with neuroendocrine carcinomas: strong correlation between PET tracer uptake and gene expression of somatostatin receptor subtype 2.

    PubMed

    Olsen, Ingrid H; Langer, Seppo W; Federspiel, Birgitte H; Oxbøl, Jytte; Loft, Annika; Berthelsen, Anne Kiil; Mortensen, Jann; Oturai, Peter; Knigge, Ulrich; Kjær, Andreas

    2016-01-01

    Somatostatin receptor expression on both protein and gene expression level was compared with in vivo (68)Ga-DOTATOC PET/CT in patients with neuroendocrine carcinomas (NEC). Twenty-one patients with verified NEC who underwent a (68)Ga-DOTATOC PET/CT between November 2012 and May 2014, were retrospectively included. By real-time polymerase chain reaction, we quantitatively determined the gene expression of several genes and compared with (68)Ga-DOTATOC PET uptake. By immunohistochemistry we qualitatively studied the expression of assorted proteins in NEC. The median age at diagnosis was 68 years (range 41-84) years. All patients had WHO performance status 0-1. Median Ki67 index was 50% (range 20-100%). Gene expression of somatostatin receptor subtype (SSTR) 2 and Ki67 were both positively correlated to the (68)Ga-DOTATOC uptake (r=0.89; p<0.0001 and r=0.5; p=0.021, respectively). Furthermore, SSTR2 and SSTR5 gene expression were strongly and positively correlated (r=0.57; p=0.006). This study as the first verifies a positive and close correlation of (68)Ga-DOTATOC uptake and gene expression of SSTR2 in NEC. SSTR2 gene expression has a stronger correlation to (68)Ga-DOTATOC uptake than SSTR5. In addition, the results indicate that the gene expression levels of SSTR2 and SSTR5 at large follow one another.

  15. Uptake of algal carbon and the synthesis of an "essential" fatty acid by Uvigerina ex. gr. semiornata (Foraminifera) within the Pakistan margin oxygen minimum zone: evidence from fatty acid biomarker and 13C tracer experiments

    NASA Astrophysics Data System (ADS)

    Larkin, K. E.; Gooday, A. J.; Woulds, C.; Jeffreys, R.; Schwartz, M.; Cowie, G.; Whitcraft, C.; Levin, L.; Dick, J. R.; Pond, D. W.

    2014-01-01

    Foraminifera are an important component of benthic communities in oxygen depleted settings, where they potentially play a~significant role in the processing of organic matter. We tracked the uptake of a 13C-labeled algal food source into individual fatty acids in the benthic foraminiferal species, Uvigerina ex. gr. semiornata, from the Arabian Sea oxygen minimum zone (OMZ). The tracer experiments were conducted on the Pakistan Margin during the late/post monsoon period (August-October 2003). A monoculture of the diatom Thalassiosira weisflogii was 13C-labeled and used to simulate a pulse of phytoplankton in two complementary experiments. A lander system was used for in situ incubations at 140 m and for 2.5 days duration, whilst a laboratory incubation used an oxystat system to maintain ambient dissolved oxygen concentrations. These shipboard experiments were terminated after 5 days. Uptake of diatoms was rapid, with high incorporation of diatom fatty acids into foraminifera after ~2 days in both experiments. Ingestion of the diatom food source was indicated by the increase over time in the quantity of diatom biomarker fatty acids in the foraminifera and by the high percentage of 13C in many of the fatty acids present at the endpoint of both in~situ and laboratory-based experiments. These results indicate that U. ex. gr. semiornata rapidly ingested the diatom food source and that this foraminifera will play an important role in the short-term cycling of organic matter within this OMZ environment. The experiments also suggested that U. ex. gr. semiornata consumed non-labeled bacterial food items, particularly bacteria, and synthesised the polyunsaturated fatty acid 20:4(n-6) de novo. 20:4(n-6) is often abundant in benthic fauna yet its origins and function have remained unclear. This study demonstrates that U. ex. gr. semiornata is capable of de novo synthesis of this "essential fatty acid" and is potentially a major source of this dietary nutrient in benthic food

  16. Uptake of algal carbon and the likely synthesis of an "essential" fatty acid by Uvigerina ex. gr. semiornata (Foraminifera) within the Pakistan margin oxygen minimum zone: evidence from fatty acid biomarker and 13C tracer experiments

    NASA Astrophysics Data System (ADS)

    Larkin, K. E.; Gooday, A. J.; Woulds, C.; Jeffreys, R. M.; Schwartz, M.; Cowie, G.; Whitcraft, C.; Levin, L.; Dick, J. R.; Pond, D. W.

    2014-07-01

    Foraminifera are an important component of benthic communities in oxygen-depleted settings, where they potentially play a significant role in the processing of organic matter. We tracked the uptake of a 13C-labelled algal food source into individual fatty acids in the benthic foraminiferal species Uvigerina ex. gr. semiornata from the Arabian Sea oxygen minimum zone (OMZ). The tracer experiments were conducted on the Pakistan margin during the late/post monsoon period (August-October 2003). A monoculture of the diatom Thalassiosira weisflogii was 13C-labelled and used to simulate a pulse of phytoplankton in two complementary experiments. A lander system was used for in situ incubations at 140 m water depth and for 2.5 days in duration. Shipboard laboratory incubations of cores collected at 140 m incorporated an oxystat system to maintain ambient dissolved oxygen concentrations and were terminated after 5 days. Uptake of diatoms was rapid, with a high incorporation of diatom fatty acids into foraminifera after ~ 2 days in both experiments. Ingestion of the diatom food source was indicated by the increase over time in the quantity of diatom biomarker fatty acids in the foraminifera and by the high percentage of 13C in many of the fatty acids present at the endpoint of both in situ and laboratory-based experiments. These results indicate that

  17. Ga-67 citrate myocardial uptake in a patient with AIDS, toxoplasmosis, and myocarditis

    SciTech Connect

    Memel, D.S.; DeRogatis, A.J.; William, D.C. )

    1991-05-01

    A 38-year-old man with AIDS presented with fever of unknown origin, splenomegaly, anemia, and thrombocytopenia. Admission laboratory data revealed a positive toxoplasmosis titer in the blood. The initial chest x-ray showed small bilateral pleural effusions, a normal cardiac silhouette, no infiltrates, and no interstitial edema. Ga-67 imaging revealed markedly abnormal uptake in the myocardium. A diagnosis of toxoplasmosis myocarditis was made based on laboratory and imaging data. The patient was treated for toxoplasmosis. No myocardial uptake of tracer was demonstrated on a follow-up Ga-67 scan, performed after completion of treatment for toxoplasmosis.

  18. Quantitative single-photon emission computed tomography/computed tomography for technetium pertechnetate thyroid uptake measurement

    PubMed Central

    Lee, Hyunjong; Kim, Ji Hyun; Kang, Yeon-koo; Moon, Jae Hoon; So, Young; Lee, Won Woo

    2016-01-01

    Abstract Objectives: Technetium pertechnetate (99mTcO4) is a radioactive tracer used to assess thyroid function by thyroid uptake system (TUS). However, the TUS often fails to deliver accurate measurements of the percent of thyroid uptake (%thyroid uptake) of 99mTcO4. Here, we investigated the usefulness of quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) after injection of 99mTcO4 in detecting thyroid function abnormalities. Materials and methods: We retrospectively reviewed data from 50 patients (male:female = 15:35; age, 46.2 ± 16.3 years; 17 Graves disease, 13 thyroiditis, and 20 euthyroid). All patients underwent 99mTcO4 quantitative SPECT/CT (185 MBq = 5 mCi), which yielded %thyroid uptake and standardized uptake value (SUV). Twenty-one (10 Graves disease and 11 thyroiditis) of the 50 patients also underwent conventional %thyroid uptake measurements using a TUS. Results: Quantitative SPECT/CT parameters (%thyroid uptake, SUVmean, and SUVmax) were the highest in Graves disease, second highest in euthyroid, and lowest in thyroiditis (P < 0.0001, Kruskal–Wallis test). TUS significantly overestimated the %thyroid uptake compared with SPECT/CT (P < 0.0001, paired t test) because other 99mTcO4 sources in addition to thyroid, such as salivary glands and saliva, contributed to the %thyroid uptake result by TUS, whereas %thyroid uptake, SUVmean and SUVmax from the SPECT/CT were associated with the functional status of thyroid. Conclusions: Quantitative SPECT/CT is more accurate than conventional TUS for measuring 99mTcO4 %thyroid uptake. Quantitative measurements using SPECT/CT may facilitate more accurate assessment of thyroid tracer uptake. PMID:27399139

  19. Estimation of Blood Flow With Radioactive Tracers

    PubMed Central

    Bassingthwaighte, James B.; Holloway, G. Allen

    2010-01-01

    The techniques of tracer dilution in the circulation, and of tracer uptake by and washout from an organ, may be described using expressions that are general and are not dependent on specific models such as exponentials. The expressions have been applied to the measurement of cardiac output using impulse and constant rate injection techniques. Further expressions have been given for estimating organ blood flow from inflow/outflow concentration-time curves, washout curves, and from the distribution of deposited tracer. Some problems with respect to the use of deposition techniques as they are ordinarily applied to the estimation of regional blood flow must be considered, particularly where there are capillary beds in series or where there is countercurrent diffusional shunting of diffusible tracers between inflow and outflow. This review deals with these various aspects of tracer theory as they relate to the measurement of blood flow. PMID:775641

  20. Congenital Abnormalities

    MedlinePlus

    ... Listen Español Text Size Email Print Share Congenital Abnormalities Page Content Article Body About 3% to 4% ... of congenital abnormalities earlier. 5 Categories of Congenital Abnormalities Chromosome Abnormalities Chromosomes are structures that carry genetic ...

  1. In vitro ¹⁴C-labeled amino acid uptake changes and surface abnormalities in the colon after 1,2-dimethylhydrazine-induced experimental carcinogenesis: protection by zinc.

    PubMed

    Chadha, Vijayta Dani; Dhawan, Devinder K

    2011-01-01

    The present study explored the regulatory role of zinc on the in vitro uptake of ¹⁴C-glucose and ¹⁴C-labeled amino acids and on colonic surface abnormalities after 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis. Rats were segregated into four groups: control, DMH-treated, zinc-treated, and DMH + zinc-treated. Colon carcinogenesis was induced through weekly subcutaneous injections of DMH (30 mg/kg body weight) for 16 weeks. Zinc (in the form of zinc sulfate) was given to rats at a dose level of 227 mg/L in their drinking water. DMH treatment caused a significant decrease in the activities of disaccharidases (sucrase, lactase, and maltase), but a significant increase in the activity of alkaline phosphatase. In vitro uptake of ¹⁴C-D-glucose and the amino acids ¹⁴C-glycine, ¹⁴C-alanine, ¹⁴C-lysine, and ¹⁴C-leucine were significantly higher in the colons of DMH-treated rats. Zinc supplementation of DMH-treated rats resulted in regulating the altered intestinal enzyme activities and in vitro uptake of ¹⁴C-amino acids and ¹⁴C-glucose. Scanning electron microscopy revealed drastic alterations in the colon surface morphology after DMH treatment, which were restored after zinc supplementation. Our results confirm a beneficial effect of zinc against DMH-induced alterations in the colons of rats.

  2. Severe asthma with markedly increased asbestos of 2 types & TXB2, and markedly reduced acetylcholine, DHEA & drug uptake in parts of upper lungs, & similar abnormalities at respiratory & cardiac center of medulla oblongata: complete elimination of this asthma within 15 days using one optimal dose of astragalus & application of strong red light & EMF neutralizer on respiratory centers of abnormal medulla oblongata.

    PubMed

    Omura, Yoshiaki; Henoch, Avraham; Shimotsuura, Yasuhira; Duvvi, Harsha; Kawashima, Hiroshi; Ohki, Motomu

    2009-01-01

    When the window of an Asbestos-contaminated room from a broken ceiling was opened wide, A 73 year-old male physician of Oriental origin, who was sitting in the next room, suddenly developed a severe asthma attack, which did not stop by the use of a hand-held Albuterol inhaler. Temporary relief was obtained only by using a Compressor-Nebulizer (Inspiration 626 with Albuterol Sulfate Inhalation Solution 0.083%). During the attack, abnormal areas were discovered at the upper lobes of both lungs, where Thromboxane B2 (TXB2) was markedly increased to 500 ng (BDORT units) (the rest of the lung had about 2.5 ng), 2 types of Asbestos (Chrysotile and Crocidolite) were abnormally increased to 0.120-0.135 mg, (BDORT units) Acetylcholine was markedly reduced to 0.5 ng (the rest of the lung was low, about 100 ng), DHEA was extremely reduced to 1 ng (the rest of the lung had about 52 ng), and telomere was less than 1 yg (= 10(-24) g). Bacterial & viral infections were also present in these abnormal areas, but no antibiotics entered the abnormal parts of the lungs. Therefore, one optimal dose of Astragalus was given once, which resulted in a rapid continuous excretion of large amounts of the above 2 types of Asbestos & TXB2 in urine & sputum, and Asthma symptoms reduced slightly in severity. Additional acupuncture & shiatsu given on all the known acupuncture points for lung disease only created slight, temporary improvement. Then, the respiratory & cardiac center of the Medulla Oblongata was found to have similar abnormalities as the lungs. Therefore, 100 mW output of Light Emitting Diode of red spectra (650 nm center spectrum) was projected on the abnormal area of the medulla oblongata on the back of the head. This resulted drug uptake of on and off and significantly reduced difficulty of breathing. Additional application of the EMF Neutralizer on the abnormal area of the Medulla Oblongata for 3 hours resulted in continuous drug uptake and complete disappearance of asthma. As a

  3. SU-E-J-122: Detecting Treatment-Induced Metabolic Abnormalities in Craniopharyngioma Patients Undergoing Surgery and Proton Therapy

    SciTech Connect

    Hua, C; Shulkin, B; Li, Y; LI, X; Merchant, T; Indelicato, D; Boop, F

    2014-06-01

    Purpose: To identify treatment-induced defects in the brain of children with craniopharyngioma receiving surgery and proton therapy using fluorodeoxyglucose positron emission tomography (FDG PET). Methods: Forty seven patients were enrolled on a clinical trial for craniopharyngioma with serial imaging and functional evaluations. Proton therapy was delivered using the double-scattered beams with a prescribed dose of 54 Cobalt Gray Equivalent. FDG tracer uptake in each of 63 anatomical regions was computed after warping PET images to a 3D reference template in Talairach coordinates. Regional uptake was deemed significantly low or high if exceeding two standard deviations of normal population from the mean. For establishing the normal ranges, 132 children aged 1–20 years with noncentral nervous system related diseases and normal-appearing cerebral PET scans were analyzed. Age- and gender-dependent regional uptake models were developed by linear regression and confidence intervals were calculated. Results: Most common PET abnormality before proton therapy was significantly low uptake in the frontal lobe, the occipital lobe (particularly in cuneus), the medial and ventral temporal lobe, cingulate gyrus, caudate nuclei, and thalamus. They were related to injury from surgical corridors, tumor mass effect, insertion of a ventricular catheter, and the placement of an Ommaya reservoir. Surprisingly a significantly high uptake was observed in temporal gyri and the parietal lobe. In 13 patients who already completed 18-month PET scans, metabolic abnormalities improved in 11 patients from baseline. One patient had persistent abnormalities. Only one revealed new uptake abnormalities in thalamus, brainstem, cerebellum, and insula. Conclusion: Postoperative FDG PET of craniopharyngioma patients revealed metabolic abnormalities in specific regions of the brain. Proton therapy did not appear to exacerbate these surgery- and tumor-induced defects. In patients with persistent and

  4. INL Tracer Interpretation

    SciTech Connect

    2007-03-27

    This spreadsheet application is for tracer test analysis. The analyses are based on the first temporal moment of a tracer. The governing equations are briefly discussed, and the individual steps required of the user are outlined. A series of Excel macros written in Visual Basic calculate mean residence time, swept pore volume, and flow-storage geometry from a tracer history.

  5. Alveolar abnormalities

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/001093.htm Alveolar abnormalities To use the sharing features on this page, please enable JavaScript. Alveolar abnormalities are changes in the tiny air sacs in ...

  6. Nail abnormalities

    MedlinePlus

    Beau's lines; Fingernail abnormalities; Spoon nails; Onycholysis; Leukonychia; Koilonychia; Brittle nails ... 2012:chap 71. Zaiac MN, Walker A. Nail abnormalities associated with systemic pathologies. Clin Dermatol . 2013;31: ...

  7. Biological tracer method

    DOEpatents

    Strong-Gunderson, Janet M.; Palumbo, Anthony V.

    1998-01-01

    The present invention is a biological tracer method for characterizing the movement of a material through a medium, comprising the steps of: introducing a biological tracer comprising a microorganism having ice nucleating activity into a medium; collecting at least one sample of the medium from a point removed from the introduction point; and analyzing the sample for the presence of the biological tracer. The present invention is also a method for using a biological tracer as a label for material identification by introducing a biological tracer having ice nucleating activity into a material, collecting a sample of a portion of the labelled material and analyzing the sample for the presence of the biological tracer.

  8. Biological tracer method

    DOEpatents

    Strong-Gunderson, J.M.; Palumbo, A.V.

    1998-09-15

    The present invention is a biological tracer method for characterizing the movement of a material through a medium, comprising the steps of: introducing a biological tracer comprising a microorganism having ice nucleating activity into a medium; collecting at least one sample of the medium from a point removed from the introduction point; and analyzing the sample for the presence of the biological tracer. The present invention is also a method for using a biological tracer as a label for material identification by introducing a biological tracer having ice nucleating activity into a material, collecting a sample of a portion of the labelled material and analyzing the sample for the presence of the biological tracer. 2 figs.

  9. Meiotic abnormalities

    SciTech Connect

    1993-12-31

    Chapter 19, describes meiotic abnormalities. These include nondisjunction of autosomes and sex chromosomes, genetic and environmental causes of nondisjunction, misdivision of the centromere, chromosomally abnormal human sperm, male infertility, parental age, and origin of diploid gametes. 57 refs., 2 figs., 1 tab.

  10. Tracer attenuation in groundwater

    NASA Astrophysics Data System (ADS)

    Cvetkovic, Vladimir

    2011-12-01

    The self-purifying capacity of aquifers strongly depends on the attenuation of waterborne contaminants, i.e., irreversible loss of contaminant mass on a given scale as a result of coupled transport and transformation processes. A general formulation of tracer attenuation in groundwater is presented. Basic sensitivities of attenuation to macrodispersion and retention are illustrated for a few typical retention mechanisms. Tracer recovery is suggested as an experimental proxy for attenuation. Unique experimental data of tracer recovery in crystalline rock compare favorably with the theoretical model that is based on diffusion-controlled retention. Non-Fickian hydrodynamic transport has potentially a large impact on field-scale attenuation of dissolved contaminants.

  11. New physical Lagrangian tracer

    SciTech Connect

    Zak, B.D.

    1984-01-01

    A physical Lagrangian tracer will be operational and available for use within the near future. The tracer is an adjustable buoyancy constant volume balloon with an onboard microprocessor to serve an appropriate array of sensors, and to control buoyancy. Tracking and data reporting is to be accomplished via the ARGOS satellite-borne data system, yielding both a local and a world-wide capability. 5 references, 1 figure.

  12. Mechanisms of Ocean Heat Uptake

    NASA Astrophysics Data System (ADS)

    Garuba, Oluwayemi

    An important parameter for the climate response to increased greenhouse gases or other radiative forcing is the speed at which heat anomalies propagate downward in the ocean. Ocean heat uptake occurs through passive advection/diffusion of surface heat anomalies and through the redistribution of existing temperature gradients due to circulation changes. Atlantic meridional overturning circulation (AMOC) weakens in a warming climate and this should slow the downward heat advection (compared to a case in which the circulation is unchanged). However, weakening AMOC also causes a deep warming through the redistributive effect, thus increasing the downward rate of heat propagation compared to unchanging circulation. Total heat uptake depends on the combined effect of these two mechanisms. Passive tracers in a perturbed CO2 quadrupling experiments are used to investigate the effect of passive advection and redistribution of temperature anomalies. A new passive tracer formulation is used to separate ocean heat uptake into contributions due to redistribution and passive advection-diffusion of surface heating during an ocean model experiment with abrupt increase in surface temperature. The spatial pattern and mechanisms of each component are examined. With further experiments, the effects of surface wind, salinity and temperature changes in changing circulation and the resulting effect on redistribution in the individual basins are isolated. Analysis of the passive advection and propagation path of the tracer show that the Southern ocean dominates heat uptake, largely through vertical and horizontal diffusion. Vertical diffusion transports the tracer across isopycnals down to about 1000m in 100 years in the Southern ocean. Advection is more important in the subtropical cells and in the Atlantic high latitudes, both with a short time scale of about 20 years. The shallow subtropical cells transport the tracer down to about 500m along isopycnal surfaces, below this vertical

  13. Octreotide Uptake in Parathyroid Adenoma

    PubMed Central

    Karaçavuş, Seyhan; Kula, Mustafa; Cihan Karaca, Züleyha; Ünlühızarcı, Kürşad; Tutuş, Ahmet; Bayram, Fahri; Çoban, Ganime

    2012-01-01

    The patient with a history of bone pain and muscle weakness, was thought to have oncogenic osteomalacia as a result of biochemical investigations and directed to Nuclear Medicine Department for a whole-body bone scintigraphy and 111In-octreotide scintigraphy. There was no focal pathologic tracer uptake, but generalized marked increase in skeletal uptake on bone scintigraphy. Octreotide scintigraphy showed accumulation of octreotide in the region of the left lobe of the thyroid gland in the neck. Thereafter, parathyroid scintigraphy was performed with technetium-99m labeled metroxy-isobutyl-isonitryl (99mTc-MIB) and MIBI scan demonstrated radiotracer uptake at the same location with octreotide scintigraphy. The patient underwent left inferior parathyroidectomy and histopathology confirmed a parathyroid adenoma. Somatostatin receptor positive parathyroid adenoma may show octreotide uptake. Octreotide scintigraphy may be promising and indicate a possibility of using somatostatin analogues for the medical treatment of somatostatin receptor positive Conflict of interest:None declared. PMID:23487397

  14. Leukocyte abnormalities.

    PubMed

    Gabig, T G

    1980-07-01

    Certain qualitative abnormalities in neutrophils and blood monocytes are associated with frequent, severe, and recurrent bacterial infections leading to fatal sepsis, while other qualitative defects demonstrated in vitro may have few or no clinical sequelae. These qualitative defects are discussed in terms of the specific functions of locomotion, phagocytosis, degranulation, and bacterial killing.

  15. Tracer Simulation Study.

    DTIC Science & Technology

    1972-04-01

    32 3. Measurement of Ignition Time ......... . . ... 34 4. Relative Reflectance Measurement .... ............ . 36 5. Laser...most reflective. Conversely, the same anomaly that was true for the laser ignition performance and for ignition energy was also true for the reflectance ... measurement ; the best weapon performance lot was not the least reflective. The use of the laser for igniting spinning tracer bullets is a practical

  16. Quantification of brain perfusion with tracers retained by the brain

    SciTech Connect

    Pupi, A.; Bacciottini, L.; De Cristofaro, M.T.R.; Formiconi, A.R.; Castagnoli, A.

    1991-12-31

    Almost a decade ago, tracers, labelled with {sup 123}I and {sup 99m}Tc, that are retained by the brain, started to be used for studies of regional brain perfusion (regional cerebral blood flow, rCBF). To date, these tracers have been used for brain perfusion imaging with SPECT in brain disorders as well as for physiological activation protocols. Only seldom, however, have they been used in protocols that quantitatively measure rCBF. Nevertheless, comparative studies with perfusion reference tracers have repeatedly demonstrated that the brain uptake of these brain-retained tracers is correlated to perfusion, the major determinant of the distribution of these tracers in the brain. The brain kinetics of {sup 99m}Tc HMPAO, which is the tracer most commonly used, was described with a two-compartment tissue model. The theoretical approach, which is, in itself, sufficient for modeling quantitative measurements with {sup 99m}Tc HMPAO, initially suggested the possibility of empirically narrowing the distance between the brain`s regional uptake of the tracer and rCBF with a linearization algorithm which uses the cerebellum as the reference region. The value of this empirical method is hampered by the fact that the cerebellum can be involved in cerebrovascular disease (i.e. cerebellar diaschisis) as well as in several other brain disorders (e.g. anxiety, and dementia of the Alzheimer type). It also was proposed that different reference regions (occipital, whole slice, or whole brain) should be selected in relation to the brain disorder under study. However, this approach does not solve the main problem because it does not equip us with a reliable tool to evaluate rCBF with a high predictive value, and, at the same time, to reduce intersubject variability. The solution would be to measure a quantitative parameter which directly reflects rCBF, such as the unidirectional influx constant of the freely diffusible flow-limited tracers. 45 refs., 3 figs., 1 tab.

  17. Tracer injection techniques in flowing surface water

    NASA Astrophysics Data System (ADS)

    Wörman, A.

    2009-04-01

    Residence time distributions for flowing water and reactive matter are commonly used integrated properties of the transport process for determining technical issues of water resource management and in eco-hydrological science. Two general issues for tracer techniques are that the concentration-vs-time relation following a tracer injection (the breakthrough curve) gives unique transport information in different parts of the curve and separation of hydromechanical and reactive mechanisms often require simultaneous tracer injections. This presentation discusses evaluation methods for simultaneous tracer injections based on examples of tracer experiments in small rivers, streams and wetlands. Tritiated water is used as a practically inert substance to reflect the actual hydrodynamics, but other involved tracers are Cr(III)-51, P-32 and N-15. Hydromechanical, in-stream dispersion is reflected as a symmetrical spreading of the spatial concentration distribution. This requires that the transport distance over water depth is larger than about five times the flow Peclet number. Transversal retention of both inert and reactive solutes is reflected in terms of the tail of the breakthrough curve. Especially, reactive solutes can have a substantial magnification of the tailing behaviour depending on reaction rates or partitioning coefficients. To accurately discriminate between the effects of reactions and hydromechanical mixing its is relevant to use simultaneous injections of inert and reactive tracers with a sequential or integrated evaluation procedure. As an example, the slope of the P-32 tailing is consistently smaller than that of a simultaneous tritium injection in Ekeby wetland, Eskilstuna. The same applies to N-15 injected in the same experiment, but nitrogen is affected also by a systematic loss due to denitrification. Uptake in stream-bed sediments can be caused by a pumping effect arising when a variable pressure field is created on the stream bottom due to bed

  18. Tracer for circulation determinations

    SciTech Connect

    Moore, H.; Santos, S.; Wysong, R. D.

    1985-03-19

    An improved tracer particle is described comprising an ion exchange core having a polymer coating thereon, the coated ion exchange core having a reaction site capable of reacting with a compound containing an oxirane group, said coated ion exchange core having been treated with a compound containing an oxirane group to react with said coated ion exchange core causing an increase in mass of the tracer particle. Preferably, the ion exchange core is labelled with a radionuclide. These particles have improved characteristics including improved stability against leaching and improved handling properties. Such particles are useful in circulatory determinations involving the injection of the particles as a suspension in a physiologically acceptable carrier or medium into the circulatory system of animals.

  19. The Potential of Carbonyl Sulfide as a Tracer for Gross Primary Productivity at Flux Tower Sites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Regional/continental scale studies of atmospheric carbonyl sulfide (OCS) seasonal dynamics and leaf level studies of plant OCS uptake have shown a close relationship to CO2 dynamics and uptake, suggesting potential for OCS as a tracer for gross primary productivity (GPP). Canopy CO2 and OCS differen...

  20. URCHIN: Reverse ray tracer

    NASA Astrophysics Data System (ADS)

    Altay, Gabriel; Theuns, Tom

    2014-12-01

    URCHIN is a Smoothed Particle Hydrodynamics (SPH) reverse ray tracer (i.e. from particles to sources). It calculates the amount of shielding from a uniform background that each particle experiences. Preservation of the adaptive density field resolution present in many gas dynamics codes and uniform sampling of gas resolution elements with rays are two of the benefits of URCHIN; it also offers preservation of Galilean invariance, high spectral resolution, and preservation of the standard uniform UV background in optically thin gas.

  1. Journal: Efficient Hydrologic Tracer-Test Design for Tracer ...

    EPA Pesticide Factsheets

    Hydrological tracer testing is the most reliable diagnostic technique available for the determination of basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test design can be difficult because of a lack of prior knowledge of the basic hydraulic and geometric parameters desired and the appropriate tracer mass to release. A new efficient hydrologic tracer-test design (EHTD) methodology has been developed to facilitate the design of tracer tests by root determination of the one-dimensional advection-dispersion equation (ADE) using a preset average tracer concentration which provides a theoretical basis for an estimate of necessary tracer mass. The method uses basic measured field parameters (e.g., discharge, distance, cross-sectional area) that are combined in functional relatipnships that descrive solute-transport processes related to flow velocity and time of travel. These initial estimates for time of travel and velocity are then applied to a hypothetical continuous stirred tank reactor (CSTR) as an analog for the hydrological-flow system to develop initial estimates for tracer concentration, tracer mass, and axial dispersion. Application of the predicted tracer mass with the hydraulic and geometric parameters in the ADE allows for an approximation of initial sample-collection time and subsequent sample-collection frequency where a maximum of 65 samples were determined to be necessary for descri

  2. Tracer tomography (in) rocks!

    NASA Astrophysics Data System (ADS)

    Somogyvári, Márk; Jalali, Mohammadreza; Jimenez Parras, Santos; Bayer, Peter

    2016-04-01

    Physical behavior of fractured aquifers is rigorously controlled by the presence of interconnected conductive fractures, as they represent the main pathways for flow and transport. Ideally, they are simulated as a discrete fracture network (DFN) in a model to capture the role of fracture system geometry, i.e. fracture length, height, and width (aperture/transmissivity). Such network may be constrained by prior geological information or direct data resources such as field mapping, borehole logging and geophysics. With the many geometric features, however, calibration of a DFN to measured data is challenging. This is especially the case when spatial properties of a fracture network need to be calibrated to flow and transport data. One way to increase the insight in a fractured rock is by combining the information from multiple field tests. In this study, a tomographic configuration that combines multiple tracer tests is suggested. These tests are conducted from a borehole with different injection levels that act as sources. In a downgradient borehole, the tracer is recorded at different levels or receivers, in order to maximize insight in the spatial heterogeneity of the rock. As tracer here we chose heat, and temperature breakthrough curves are recorded. The recorded tracer data is inverted using a novel stochastic trans-dimensional Markov Chain Monte Carlo procedure. An initial DFN solution is generated and sequentially modified given available geological information, such as expected fracture density, orientation, length distribution, spacing and persistency. During this sequential modification, the DFN evolves in a trans-dimensional inversion space through adding and/or deleting fracture segments. This stochastic inversion algorithm requires a large number of thousands of model runs to converge, and thus using a fast and robust forward model is essential to keep the calculation efficient. To reach this goal, an upwind coupled finite difference method is employed

  3. Tracers and Tracer Testing: Design, Implementation, Tracer Selection, and Interpretation Methods

    SciTech Connect

    G. Michael Shook; Shannon L.; Allan Wylie

    2004-01-01

    Conducting a successful tracer test requires adhering to a set of steps. The steps include identifying appropriate and achievable test goals, identifying tracers with the appropriate properties, and implementing the test as designed. When these steps are taken correctly, a host of tracer test analysis methods are available to the practitioner. This report discusses the individual steps required for a successful tracer test and presents methods for analysis. The report is an overview of tracer technology; the Suggested Reading section offers references to the specifics of test design and interpretation.

  4. 68Ga-DOTATATE uptake in pineal gland, a rare physiological variant: case series.

    PubMed

    Riaz, Saima; Syed, Rizwan; Skoura, Evangelia; Alshammari, Alshaima; Gaze, Mark; Sajjan, Rakesh; Halsey, Richard; Bomanji, Jamshed

    2015-11-01

    (68)Ga-DOTATATE PET-CT is widely used for the evaluation of neuroendocrine tumours. Knowledge of the physiological distribution of the radiotracer is of critical importance in characterizing focal areas of uptake. In this case series, we report three paediatric cases (average age 4.7 years ± 0.6 SD) with diagnosed advanced stage IV Neuroblastoma. Two had (68)Ga-DOTATATE PET-CT scans and one underwent (68)Ga-DOTATATE PET-MRI scan to assess for suitability of molecular therapy. Focal increased tracer uptake in the pineal gland was noted in all cases with no morphological abnormality on the corresponding CT and MRI scans. The uptake within the gland was thought to be a physiological variant rather than metastases owing to the heterogeneity of somatostatin receptors expression. The pineal gland has been reported to express somatostatin receptors. The physiological distribution of (68)Ga-DOTATATE uptake in the pineal gland is not routinely seen. Furthermore, the possibility of pineal meningioma is very unlikely as pineal meningiomas are very rare and there was no convincing morphological evidence of meningiomas on CT/MRI scan.

  5. Tracer-Test Planning Using the Efficient Hydrologic Tracer ...

    EPA Pesticide Factsheets

    Hydrological tracer testing is the most reliable diagnostic technique available for establishing flow trajectories and hydrologic connections and for determining basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test design can be difficult because of a lack of prior knowledge of the basic hydraulic and geometric parameters desired and the appropriate tracer mass to release. A new efficient hydrologic tracer-test design (EHTD) methodology has been developed that combines basic measured field parameters (e.g., discharge, distance, cross-sectional area) in functional relationships that describe solute-transport processes related to flow velocity and time of travel. The new method applies these initial estimates for time of travel and velocity to a hypothetical continuously stirred tank reactor as an analog for the hydrologic flow system to develop initial estimates for tracer concentration and axial dispersion, based on a preset average tracer concentration. Root determination of the one-dimensional advection-dispersion equation (ADE) using the preset average tracer concentration then provides a theoretical basis for an estimate of necessary tracer mass.Application of the predicted tracer mass with the hydraulic and geometric parameters in the ADE allows for an approximation of initial sample-collection time and subsequent sample-collection frequency where a maximum of 65 samples were determined to be

  6. Comparison of three magnetic nanoparticle tracers for sentinel lymph node biopsy in an in vivo porcine model

    PubMed Central

    Pouw, Joost J; Ahmed, Muneer; Anninga, Bauke; Schuurman, Kimberley; Pinder, Sarah E; Van Hemelrijck, Mieke; Pankhurst, Quentin A; Douek, Michael; ten Haken, Bennie

    2015-01-01

    Introduction Breast cancer staging with sentinel lymph node biopsy relies on the use of radioisotopes, which limits the availability of the procedure worldwide. The use of a magnetic nanoparticle tracer and a handheld magnetometer provides a radiation-free alternative, which was recently evaluated in two clinical trials. The hydrodynamic particle size of the used magnetic tracer differs substantially from the radioisotope tracer and could therefore benefit from optimization. The aim of this study was to assess the performance of three different-sized magnetic nanoparticle tracers for sentinel lymph node biopsy within an in vivo porcine model. Materials and methods Sentinel lymph node biopsy was performed within a validated porcine model using three magnetic nanoparticle tracers, approved for use in humans (ferumoxytol, with hydrodynamic diameter dH =32 nm; Sienna+®, dH =59 nm; and ferumoxide, dH =111 nm), and a handheld magnetometer. Magnetometer counts (transcutaneous and ex vivo), iron quantification (vibrating sample magnetometry), and histopathological assessments were performed on all ex vivo nodes. Results Transcutaneous “hotspots” were present in 12/12 cases within 30 minutes of injection for the 59 nm tracer, compared to 7/12 for the 32 nm tracer and 8/12 for the 111 nm tracer, at the same time point. Ex vivo magnetometer counts were significantly greater for the 59 nm tracer than for the other tracers. Significantly more nodes per basin were excised for the 32 nm tracer compared to other tracers, indicating poor retention of the 32 nm tracer. Using the 59 nm tracer resulted in a significantly higher iron accumulation compared to the 32 nm tracer. Conclusion The 59 nm tracer demonstrated rapid lymphatic uptake, retention in the first nodes reached, and accumulation in high concentration, making it the most suitable tracer for intraoperative sentinel lymph node localization. PMID:25709445

  7. Graphical Analysis of PET Data Applied to Reversible and Irreversible Tracers

    SciTech Connect

    Logan, Jean

    1999-11-18

    Graphical analysis refers to the transformation of multiple time measurements of plasma and tissue uptake data into a linear plot, the slope of which is related to the number of available tracer binding sites. This type of analysis allows easy comparisons among experiments. No particular model structure is assumed, however it is assumed that the tracer is given by bolus injection and that both tissue uptake and the plasma concentration of unchanged tracer are monitored following tracer injection. The requirement of plasma measurements can be eliminated in some cases when a reference region is available. There are two categories of graphical methods which apply to two general types of ligands--those which bind reversibly during the scanning procedure and those which are irreversible or trapped during the time of the scanning procedure.

  8. Exotic tracers for atmospheric studies

    NASA Astrophysics Data System (ADS)

    Lovelock, James E.; Ferber, Gilbert J.

    Tracer materials can be injected into the atmosphere to study transport and dispersion processes and to validate air pollution model calculations. Tracers should be inert, non-toxic and harmless to the environment. Tracers for long-range experiments, where dilution is very great, must be measurable at extremely low concentrations, well below the parts per trillion level. Compounds suitable for long-range tracer work are rare and efforts should be made to reserve them for meteorological studies, barring them from commercial uses which would increase atmospheric background concentrations. The use of these exotic tracers, including certain perfluorocarbons and isotopically labelled methanes, should be coordinated within the meteorological community to minimize interferences and maximize research benefits.

  9. Definition, properties, and Atlantic Ocean distribution of the new tracer TrOCA

    NASA Astrophysics Data System (ADS)

    Touratier, Franck; Goyet, Catherine

    2004-05-01

    Natural and anthropogenic tracers in the ocean are widely used not only to better understand water masses circulation and mixing but also to understand and quantify the ocean uptake and storage capacity of greenhouse gases. However, since each tracer is different, it is best to use the complementarity of several tracers to unequivocally identify the various water masses. Here we illustrate the conservative properties and the spatial distribution of the new composite tracer TrOCA ( Tracer combining Oxygen, inorganic Carbon, and total Alkalinity) using oxygen (O 2), dissolved inorganic carbon (TCO 2), and total alkalinity (TA), from the Atlantic Ocean. The significant accuracy improvement of TCO 2 and TA measurements since the 1970s, combined to a large effort in measuring these parameters during large scale cruises throughout the Atlantic Ocean, makes this tracer TrOCA an additional tool in analyzing water mass distribution. This tracer is shown to be conservative in intermediate, deep, and bottom waters. For instance, we show that the independence of TrOCA from other tracers provides further information on the origin and mixing of the main Atlantic water masses. Furthermore, TrOCA combined with the composite tracer NO, in particular the ratio TrOCA/NO, can be used to unequivocally identify and separate the Antarctic Intermediate Water, the Antarctic Bottom Water, and the North Atlantic Deep Water.

  10. A novel PET tracer for evaluation of gene therapy

    SciTech Connect

    Goldman, S.; Monclus, M.; Cool, V.

    1996-05-01

    A promising approach of gene therapy for cancer consist in the transduction of neoplastic cells with the herpes virus thymidine-kinase gene (HSV-tk) which renders transduced cells sensitive to the lethal effect of anti-viral agent such as ganciclovir (GCV). Pet with adapted radiotracers represents an adequate tool to determine in vivo the level of HSV-tk expression and to establish the optimal protocol of gene and GCV administrations in human. We have developed a new potential PET tracer, 9-((1-[F-18]fluoro-3-hydroxy-2-propoxy)methyl)guanine [F-18]FHPG should theoretically accumulate in cells expressing HSV-tk. [F-18]FHPG was obtained by nucleophilic substitution on a ditosylate precursor followed by hydrolysis. To determine the biological behavior of this compound, we synthetized the corresponding non radioactive fluorinated analog (FHPG) and tested its inhibitory activity on HSV-tk transduced 9L gliosarcoma cells maintained in culture. FHPG at 100 {mu}M suppress cell growth by 50% while GCV and acyclovir induced 100% suppression at 10 and 100 {mu}M, respectively. We then tested the in vitro uptake of n.c.a. [F-18]FHPG in cultured cells transduced with HSV-tk or a control gene (neomycin). Ratio of [F-18]FHPG uptake in HSV-tk versus control cells was 240 after 6 hours of incubation. In vivo uptake of [F-18]FHPG was tested in experimental tumors obtained by stereotactical implantion of transduced 9L cells in the brain of male Fischer 344 rats. Ratio of [F-18]FHPG uptake in HSV-tk versus control tumors was 2.5, 3 hours after intravenous tracer injection. Uptake in HSV-tk tumor was 19-fold higher than in the cortex. We concluded that [F-18]FHPG is a promising PET tracer for the evaluation of gene therapy involving viral thymidine kinase genes.

  11. Tracer airflow measurement system (TRAMS)

    DOEpatents

    Wang, Duo

    2007-04-24

    A method and apparatus for measuring fluid flow in a duct is disclosed. The invention uses a novel high velocity tracer injector system, an optional insertable folding mixing fan for homogenizing the tracer within the duct bulk fluid flow, and a perforated hose sampling system. A preferred embodiment uses CO.sub.2 as a tracer gas for measuring air flow in commercial and/or residential ducts. In extant commercial buildings, ducts not readily accessible by hanging ceilings may be drilled with readily plugged small diameter holes to allow for injection, optional mixing where desired using a novel insertable foldable mixing fan, and sampling hose.

  12. Pharmacokinetic Modeling of Manganese III. Physiological Approaches Accounting for Background and Tracer Kinetics

    SciTech Connect

    Teeguarden, Justin G.; Gearhart, Jeffrey; Clewell, III, H. J.; Covington, Tammie R.; Nong, Andy; Anderson, Melvin E.

    2007-01-01

    Manganese (Mn) is an essential nutrient. Mn deficiency is associated with altered lipid (Kawano et al. 1987) and carbohydrate metabolism (Baly et al. 1984; Baly et al. 1985), abnormal skeletal cartilage development (Keen et al. 2000), decreased reproductive capacity, and brain dysfunction. Occupational and accidental inhalation exposures to aerosols containing high concentrations of Mn produce neurological symptoms with Parkinson-like characteristics in workers. At present, there is also concern about use of the manganese-containing compound, methylcyclopentadienyl manganese tricarbonyl (MMT), in unleaded gasoline as an octane enhancer. Combustion of MMT produces aerosols containing a mixture of manganese salts (Lynam et al. 1999). These Mn particulates may be inhaled at low concentrations by the general public in areas using MMT. Risk assessments for essential elements need to acknowledge that risks occur with either excesses or deficiencies and the presence of significant amounts of these nutrients in the body even in the absence of any exogenous exposures. With Mn there is an added complication, i.e., the primary risk is associated with inhalation while Mn is an essential dietary nutrient. Exposure standards for inhaled Mn will need to consider the substantial background uptake from normal ingestion. Andersen et al. (1999) suggested a generic approach for essential nutrient risk assessment. An acceptable exposure limit could be based on some ‘tolerable’ change in tissue concentration in normal and exposed individuals, i.e., a change somewhere from 10 to 25 % of the individual variation in tissue concentration seen in a large human population. A reliable multi-route, multi-species pharmacokinetic model would be necessary for the implementation of this type of dosimetry-based risk assessment approach for Mn. Physiologically-based pharmacokinetic (PBPK) models for various xenobiotics have proven valuable in contributing to a variety of chemical specific risk

  13. Driven tracers in narrow channels

    NASA Astrophysics Data System (ADS)

    Cividini, J.; Mukamel, D.; Posch, H. A.

    2017-01-01

    Steady-state properties of a driven tracer moving in a narrow two-dimensional (2D) channel of quiescent medium are studied. The tracer drives the system out of equilibrium, perturbs the density and pressure fields, and gives the bath particles a nonzero average velocity, creating a current in the channel. Three models in which the confining effect of the channel is probed are analyzed and compared in this study: the first is the simple symmetric exclusion process (SSEP), for which the stationary density profile and the pressure on the walls in the frame of the tracer are computed. We show that the tracer acts like a dipolar source in an average velocity field. The spatial structure of this 2D strip is then simplified to a one-dimensional (1D) SSEP, in which exchanges of position between the tracer and the bath particles are allowed. Using a combination of mean-field theory and exact solution in the limit where no exchange is allowed gives good predictions of the velocity of the tracer and the density field. Finally, we show that results obtained for the 1D SSEP with exchanges also apply to a gas of overdamped hard disks in a narrow channel. The correspondence between the parameters of the SSEP and of the gas of hard disks is systematic and follows from simple intuitive arguments. Our analytical results are checked numerically.

  14. Complex functionality with minimal computation: Promise and pitfalls of reduced-tracer ocean biogeochemistry models

    NASA Astrophysics Data System (ADS)

    Galbraith, Eric D.; Dunne, John P.; Gnanadesikan, Anand; Slater, Richard D.; Sarmiento, Jorge L.; Dufour, Carolina O.; de Souza, Gregory F.; Bianchi, Daniele; Claret, Mariona; Rodgers, Keith B.; Marvasti, Seyedehsafoura Sedigh

    2015-12-01

    Earth System Models increasingly include ocean biogeochemistry models in order to predict changes in ocean carbon storage, hypoxia, and biological productivity under climate change. However, state-of-the-art ocean biogeochemical models include many advected tracers, that significantly increase the computational resources required, forcing a trade-off with spatial resolution. Here, we compare a state-of-the art model with 30 prognostic tracers (TOPAZ) with two reduced-tracer models, one with 6 tracers (BLING), and the other with 3 tracers (miniBLING). The reduced-tracer models employ parameterized, implicit biological functions, which nonetheless capture many of the most important processes resolved by TOPAZ. All three are embedded in the same coupled climate model. Despite the large difference in tracer number, the absence of tracers for living organic matter is shown to have a minimal impact on the transport of nutrient elements, and the three models produce similar mean annual preindustrial distributions of macronutrients, oxygen, and carbon. Significant differences do exist among the models, in particular the seasonal cycle of biomass and export production, but it does not appear that these are necessary consequences of the reduced tracer number. With increasing CO2, changes in dissolved oxygen and anthropogenic carbon uptake are very similar across the different models. Thus, while the reduced-tracer models do not explicitly resolve the diversity and internal dynamics of marine ecosystems, we demonstrate that such models are applicable to a broad suite of major biogeochemical concerns, including anthropogenic change. These results are very promising for the further development and application of reduced-tracer biogeochemical models that incorporate "sub-ecosystem-scale" parameterizations.

  15. Efficiency gains in tracer identification for nuclear imaging: can in vivo LC-MS/MS evaluation of small molecules screen for successful PET tracers?

    PubMed

    Joshi, Elizabeth M; Need, Anne; Schaus, John; Chen, Zhaogen; Benesh, Dana; Mitch, Charles; Morton, Stuart; Raub, Thomas J; Phebus, Lee; Barth, Vanessa

    2014-12-17

    Positron emission tomography (PET) imaging has become a useful noninvasive technique to explore molecular biology within living systems; however, the utility of this method is limited by the availability of suitable radiotracers to probe specific targets and disease biology. Methods to identify potential areas of improvement in the ability to predict small molecule performance as tracers prior to radiolabeling would speed the discovery of novel tracers. In this retrospective analysis, we characterized the brain penetration or peak SUV (standardized uptake value), binding potential (BP), and brain exposure kinetics across a series of known, nonradiolabeled PET ligands using in vivo LC-MS/MS (liquid chromatography coupled to mass spectrometry) and correlated these parameters with the reported PET ligand performance in nonhuman primates and humans available in the literature. The PET tracers studied included those reported to label G protein-coupled receptors (GPCRs), intracellular enzymes, and transporters. Additionally, data for each tracer was obtained from a mouse brain uptake assay (MBUA), previously published, where blood-brain barrier (BBB) penetration and clearance parameters were assessed and compared against similar data collected on a broad compound set of central nervous system (CNS) therapeutic compounds. The BP and SUV identified via nonradiolabeled LC-MS/MS, while different from the published values observed in the literature PET tracer data, allowed for an identification of initial criteria values we sought to facilitate increased potential for success from our early discovery screening paradigm. Our analysis showed that successful, as well as novel, clinical PET tracers exhibited BP of greater than 1.5 and peak SUVs greater than approximately 150% at 5 min post dose in rodents. The brain kinetics appeared similar between both techniques despite differences in tracer dose, suggesting linearity across these dose ranges. The assessment of tracers in a

  16. Modelling Water Uptake Provides a New Perspective on Grass and Tree Coexistence.

    PubMed

    Mazzacavallo, Michael G; Kulmatiski, Andrew

    2015-01-01

    Root biomass distributions have long been used to infer patterns of resource uptake. These patterns are used to understand plant growth, plant coexistence and water budgets. Root biomass, however, may be a poor indicator of resource uptake because large roots typically do not absorb water, fine roots do not absorb water from dry soils and roots of different species can be difficult to differentiate. In a sub-tropical savanna, Kruger Park, South Africa, we used a hydrologic tracer experiment to describe the abundance of active grass and tree roots across the soil profile. We then used this tracer data to parameterize a water movement model (Hydrus 1D). The model accounted for water availability and estimated grass and tree water uptake by depth over a growing season. Most root biomass was found in shallow soils (0-20 cm) and tracer data revealed that, within these shallow depths, half of active grass roots were in the top 12 cm while half of active tree roots were in the top 21 cm. However, because shallow soils provided roots with less water than deep soils (20-90 cm), the water movement model indicated that grass and tree water uptake was twice as deep as would be predicted from root biomass or tracer data alone: half of grass and tree water uptake occurred in the top 23 and 43 cm, respectively. Niche partitioning was also greater when estimated from water uptake rather than tracer uptake. Contrary to long-standing assumptions, shallow grass root distributions absorbed 32% less water than slightly deeper tree root distributions when grasses and trees were assumed to have equal water demands. Quantifying water uptake revealed deeper soil water uptake, greater niche partitioning and greater benefits of deep roots than would be estimated from root biomass or tracer uptake data alone.

  17. Modelling Water Uptake Provides a New Perspective on Grass and Tree Coexistence

    PubMed Central

    2015-01-01

    Root biomass distributions have long been used to infer patterns of resource uptake. These patterns are used to understand plant growth, plant coexistence and water budgets. Root biomass, however, may be a poor indicator of resource uptake because large roots typically do not absorb water, fine roots do not absorb water from dry soils and roots of different species can be difficult to differentiate. In a sub-tropical savanna, Kruger Park, South Africa, we used a hydrologic tracer experiment to describe the abundance of active grass and tree roots across the soil profile. We then used this tracer data to parameterize a water movement model (Hydrus 1D). The model accounted for water availability and estimated grass and tree water uptake by depth over a growing season. Most root biomass was found in shallow soils (0–20 cm) and tracer data revealed that, within these shallow depths, half of active grass roots were in the top 12 cm while half of active tree roots were in the top 21 cm. However, because shallow soils provided roots with less water than deep soils (20–90 cm), the water movement model indicated that grass and tree water uptake was twice as deep as would be predicted from root biomass or tracer data alone: half of grass and tree water uptake occurred in the top 23 and 43 cm, respectively. Niche partitioning was also greater when estimated from water uptake rather than tracer uptake. Contrary to long-standing assumptions, shallow grass root distributions absorbed 32% less water than slightly deeper tree root distributions when grasses and trees were assumed to have equal water demands. Quantifying water uptake revealed deeper soil water uptake, greater niche partitioning and greater benefits of deep roots than would be estimated from root biomass or tracer uptake data alone. PMID:26633177

  18. Dyes as tracers for vadose zone hydrology

    NASA Astrophysics Data System (ADS)

    Flury, Markus; Wai, Nu Nu

    2003-03-01

    Dyes are important tracers to investigate subsurface water movement. For more than a century, dye tracers have provided clues about the hydrological cycle as well as flow and transport processes in the subsurface. Groundwater contamination often originates in the vadose zone. Agrochemicals applied to the soil surface, toxic compounds accidentally spilled by human activities, and contaminants released from waste repositories leach through the vadose zone and can ultimately pollute groundwater resources. Dyes are an important tool to assess flow pathways of such contaminants. This review compiles information on dyes used as hydrological tracers, with particular emphasis on vadose zone hydrology. We summarize briefly different human-applied tracers, including nondye tracers. We then provide a historical sketch of the use of dyes as tracers and describe newer developments in visualization and quantification of tracer experiments. Relevant chemical properties of dyes used as tracers are discussed and illustrated with dye intermediates and selected dye tracers. The types of dyes used as tracers in subsurface hydrology are summarized, and recommendations are made regarding the use of dye tracers. The review concludes with a toxicological assessment of dyes used as hydrological tracers. Many different dyes have been proposed as tracers for water movement in the subsurface. All of these compounds, however, are to some degree retarded by the subsurface medium. Nevertheless, dyes are useful tracers to visualize flow pathways.

  19. Variability of Interhemispheric Tracer Transport

    NASA Astrophysics Data System (ADS)

    Wu, X.; Waugh, D.; Orbe, C.; Yang, H.

    2015-12-01

    Understanding the interhemispheric transport helps us track the movement of air and potential dispersion of pollutions. Here we examine variations of the transport from NH mid-latitudes using NCAR CAM-chem model simulations of an idealized clock tracer (that yields the "mean age") and idealized tracers with 5-day and 50-day decay times. We examine the seasonal and interannual variations in the tracers (and inferred transport time scales), and relate to meteorological processes and climate modes. It is shown that there are large seasonal variations in the interhemispheric transport time scales but generally smaller interannual variations. The significant interannual variations are found over the Indian Ocean, and linked to the Asian monsoon and seasonal movement of intense convection. Smaller variations are found over the Eastern Pacific and linked to seasonality of the ITCZ and ENSO.

  20. Following Footsteps: ECD Tracer Studies.

    ERIC Educational Resources Information Center

    Smale, Jim, Editor

    2002-01-01

    This document consists of the single 2002 issue of The Bernard van Leer Foundation's "Early Childhood Matters," a periodical addressed to practitioners in the field of early childhood education and including information on projects funded by the Foundation. Articles in this issue focus on early childhood development tracer studies of…

  1. Bioethics. LC Science Tracer Bullet.

    ERIC Educational Resources Information Center

    Martin, Cathy, Comp.; Cadoree, Michelle

    This guide lists published materials on many aspects of bioethics, the literature of which is varied and scattered. Related guides in the LC Science Tracer Bullet series are TB 80-9, Terminal Care, TB 80-11, Drug Research on Human Subjects, TB 83-4, Science Policy, and TB 84-7, Biotechnology. Not intended to be a comprehensive bibliography, this…

  2. Urine - abnormal color

    MedlinePlus

    ... medlineplus.gov/ency/article/003139.htm Urine - abnormal color To use the sharing features on this page, please enable JavaScript. The usual color of urine is straw-yellow. Abnormally colored urine ...

  3. Tooth - abnormal colors

    MedlinePlus

    ... medlineplus.gov/ency/article/003065.htm Tooth - abnormal colors To use the sharing features on this page, please enable JavaScript. Abnormal tooth color is any color other than white to yellowish- ...

  4. Abnormal Head Position

    MedlinePlus

    ... cause. Can a longstanding head turn lead to any permanent problems? Yes, a significant abnormal head posture could cause permanent ... occipitocervical synostosis and unilateral hearing loss. Are there any ... postures? Yes. Abnormal head postures can usually be improved depending ...

  5. Skeletal limb abnormalities

    MedlinePlus

    ... medlineplus.gov/ency/article/003170.htm Skeletal limb abnormalities To use the sharing features on this page, please enable JavaScript. Skeletal limb abnormalities refers to a variety of bone structure problems ...

  6. Abnormal Uterine Bleeding FAQ

    MedlinePlus

    ... PROBLEMS Abnormal Uterine Bleeding • What is a normal menstrual cycle? • When is bleeding abnormal? • At what ages is ... treat abnormal bleeding? •Glossary What is a normal menstrual cycle? The normal length of the menstrual cycle is ...

  7. Etiology of amyloidosis determines myocardial 99mTc-DPD uptake in amyloidotic cardiomyopathy.

    PubMed

    Longhi, Simone; Bonfiglioli, Rachele; Obici, Laura; Gagliardi, Christian; Milandri, Agnese; Lorenzini, Massimiliano; Guidalotti, Pier Luigi; Merlini, Giampaolo; Rapezzi, Claudio

    2015-05-01

    Tc-DPD (Tc-3,3-diphosphono-1,2-propanodicarboxylic acid) has a high affinity for transthyretin (TTR)-infiltrated myocardium, allowing a differential diagnosis with light chain cardiac amyloidosis and other nonamyloidotic cardiomyopathies with a hypertrophic phenotype, in which myocardial tracer uptake is low or absent. Myocardial bone tracer uptake in the rarer forms of amyloidosis (eg, apolipoprotein-related) has been rarely studied. We present 4 cases of cardiac amyloidosis that underwent Tc-DPD scintigraphy; myocardial DPD uptake was present in patients with ATTR, wtTTR and apolipoprotein AI and negative in cases with AL and apolipoprotein AII-related disease.

  8. Hepatic uptake of technetium-99m diphosphonate in thalassemia major

    SciTech Connect

    Levy, H.M.; Smith, R.

    1986-02-01

    Two cases of thalassemia major are presented in which bone scintigraphy demonstrated diffuse hepatic uptake of Tc-99m diphosphonate. Although abnormal splenic and renal uptake of Tc-99m phosphates has been reported in patients with thalassemia major, hepatic uptake has not been reported previously. This scintigraphic finding is presumably due to increased iron deposition in the liver, resulting from increased iron turnover and retention in these patients and from multiple previous blood transfusions.

  9. Increased skeletal:renal uptake ratio. [Bone-seekers

    SciTech Connect

    Cheng, T.H.; Holman, B.L.

    1980-08-01

    Twenty-four patients with increased skeletal:renal uptake ratios of /sup 99m/Tc-methylene diphosphonate were studied. Increased uptake was central in metastatic prostate carcinoma, peripheral in hematologic disorders, and heterogeneous in Paget disease and fibrous dysplasia. There was no discernible redistribution of skeletal uptake in patients with renal failure. Absence of both renal and bladder activity was not observed in patients with normal renal function. An increased ratio was always abnormal and frequently indicated diffuse bone disease.

  10. Tracer diffusion inside fibrinogen layers

    NASA Astrophysics Data System (ADS)

    Cieśla, Michał; Gudowska-Nowak, Ewa; Sagués, Francesc; Sokolov, Igor M.

    2014-01-01

    We investigate the obstructed motion of tracer (test) particles in crowded environments by carrying simulations of two-dimensional Gaussian random walk in model fibrinogen monolayers of different orientational ordering. The fibrinogen molecules are significantly anisotropic and therefore they can form structures where orientational ordering, similar to the one observed in nematic liquid crystals, appears. The work focuses on the dependence between level of the orientational order (degree of environmental crowding) of fibrinogen molecules inside a layer and non-Fickian character of the diffusion process of spherical tracer particles moving within the domain. It is shown that in general particles motion is subdiffusive and strongly anisotropic, and its characteristic features significantly change with the orientational order parameter, concentration of fibrinogens, and radius of a diffusing probe.

  11. Multiple-tracer gas analyzer

    SciTech Connect

    Uhl, J.E.

    1982-01-01

    A multi-gas tracer system has been designed, built, and used on an explosively fractured oil shale rubble bed. This paper deals exclusively with the hardware, software, and overall operation of the tracer system. This system is a field portable, self-contained unit, which utilizes a mass spectrometer for gas analysis. The unit has a 20 channel sample port capability and is controlled by a desk top computer. The system is configured to provide a dynamic sensitivity range of up to six orders of magnitude. A roots blower is manifolded to the unit to provide continuous flow in all sample lines. The continuous flow process allows representative samples as well as decreasing the time between each measurement. Typical multiplex cycle time to evaluate four unique gases is approximately 12 seconds.

  12. Measurement of discharge using tracers

    USGS Publications Warehouse

    Kilpatrick, F.A.; Cobb, Ernest D.

    1985-01-01

    The development of fluorescent dyes and fluorometers that can measure these dyes at very low concentrations has made dye-dilution methods practical for measuring discharge. These methods are particularly useful for determining discharge under certain flow conditions that are unfavorable for current meter measurements. These include small streams, canals, and pipes where 1. Turbulence is excessive for current-meter measurement but conducive to good mixing. 2. Moving rocks and debris may damage instruments placed in the flow. 3. Cross-sectional areas or velocities are indeterminate or changing. 4. The flow is unsteady, such as the flow that exists with storm-runoff events on small streams and urban storm-sewer systems. 5. The flow is physically inaccessible or unsafe. From a practical standpoint, such methods are limited primarily to small streams, because of the excessively long channel-mixing lengths required for larger streams. Very good accuracy can be obtained provided that 1. Adequate mixing length and time are allowed. 2. Careful field and laboratory techniques are used. 3. Dye losses are not significant. This manual describes the slug-injection and constant-rate injection methods of performing tracer-dilution measurements. Emphasis is on the use of fluorescent dyes as tracers and the equipment, field methods, and laboratory procedures for performing such measurements. The tracer-velocity method is also briefly discussed.

  13. Tracer mixing at fracture intersections

    SciTech Connect

    Li, Guomin

    2001-02-10

    Discrete network models are one of the approaches used to simulate a dissolved contaminant, which is usually represented as a tracer in modeling studies, in fractured rocks. The discrete models include large numbers of individual fractures within the network structure, with flow and transport described on the scale of an individual fracture. Numerical simulations for the mixing characteristics and transfer probabilities of a tracer through a fracture intersection are performed for this study. A random-walk, particle-tracking model is applied to simulate tracer transport in fracture intersections by moving particles through space using individual advective and diffusive steps. The simulation results are compared with existing numerical and analytical solutions for a continuous intersection over a wide range of Peclet numbers. This study attempts to characterize the relative concentration at the outflow branches for a continuous intersection with different flow fields. The simulation results demonstrate that the mixing characteristics at the fracture intersections are a function not only of the Peclet number but also of the flow field pattern.

  14. Study on kinetics of glucose uptake by some species of plankton

    NASA Astrophysics Data System (ADS)

    Li, Wenquan; Wang, Xian; Zhang, Yaohua

    1993-03-01

    The rates of glucose uptake by some species of plankton were determined by3H-glucose tracer method. Experimental results indicated that the observed glucose uptake at natural seawater concentrations by Platymonas subcordiformis and Brachionus plicatilis was principally a metabolic process fitted with the Michaelis-Menten equation in the range of adaptive temperatures. Heterotrophic uptake by Platymonas subcordiformis was mainly dependent on diffusion at high glucose levels. The uptake by Brachionus plicatilis showed active transport even at high glucose levels, indicating its high heterotrophic activity. The uptake rate by Artemia salina was lower, and its V m/K ratio was lower than those of the other two species of plankton.

  15. Kinetic analysis of 18F-fluorodihydrorotenone as a deposited myocardial flow tracer: Comparison to thallium-201.

    SciTech Connect

    Marshall, Robert C.; Powers-Risius, Patricia; Reutter, Bryan W.; O'Neil, James P.; La Belle, Michael; Huesman, Ronald H.; VanBrocklin, Henry F.

    2004-03-01

    The goal of this investigation was to assess the accuracy of 18F-fluorodihydrorotenone (18F-FDHR) as a new deposited myocardial flow tracer and compare the results to those for 201Tl. Methods. The kinetics of these flow tracers were evaluated in 22 isolated, erythrocyte- and albumin-perfused rabbit hearts over a flow range encountered in patients. The two flow tracers plus a vascular reference tracer (131I-albumin) were introduced as a bolus through a port just above the aortic cannula. Myocardial extraction, retention, washout, and uptake parameters were computed from the venous outflow curves using the multiple indicator dilution technique and spectral analysis. Results. The mean initial extraction fractions of 18F-FDHR (0.85 +- 0.07) and 201Tl (0.87 +- 0.05) were not significantly different, although the initial extraction fraction for 18F-FDHR declined with flow (P < 0.0001), whereas the initial extraction fraction of 201Tl did not. Washout of 201Tl was faster (P < 0.001) and more affected by flow (P < 0.05) than 18F-FDHR washout. Except for initial extraction fraction, 18F-FDHR retention was greater (P < 0.001) and less affected by flow (P < 0.05) than 201Tl retention. Reflecting its superior retention, net uptake of 18F-FDHR was better correlated with flow than 201Tl uptake at both one and fifteen minutes after tracer introduction (P < 0.0001 for both comparisons). Conclusion. The superior correlation of 18F-FDHR uptake with flow indicates that it is a better flow tracer than 201Tl in the isolated rabbit heart. Compared to the other currently available positron-emitting flow tracers (82Rb, 13N-ammonia, and 15O-water), 18F-FDHR has the potential of providing excellent image resolution without the need for an on-site cyclotron.

  16. STRATEGIES FOR QUANTIFYING PET IMAGING DATA FROM TRACER STUDIES OF BRAIN RECEPTORS AND ENZYMES.

    SciTech Connect

    Logan, J.

    2001-04-02

    A description of some of the methods used in neuroreceptor imaging to distinguish changes in receptor availability has been presented in this chapter. It is necessary to look beyond regional uptake of the tracer since uptake generally is affected by factors other than the number of receptors for which the tracer has affinity. An exception is the infusion method producing an equilibrium state. The techniques vary in complexity some requiring arterial blood measurements of unmetabolized tracer and multiple time uptake data. Others require only a few plasma and uptake measurements and those based on a reference region require no plasma measurements. We have outlined some of the limitations of the different methods. Laruelle (1999) has pointed out that test/retest studies to which various methods can be applied are crucial in determining the optimal method for a particular study. The choice of method will also depend upon the application. In a clinical setting, methods not involving arterial blood sampling are generally preferred. In the future techniques for externally measuring arterial plasma radioactivity with only a few blood samples for metabolite correction will extend the modeling options of clinical PET. Also since parametric images can provide information beyond that of ROI analysis, improved techniques for generating such images will be important, particularly for ligands requiring more than a one-compartment model. Techniques such as the wavelet transform proposed by Turkheimer et al. (2000) may prove to be important in reducing noise and improving quantitation.

  17. Coupled Effects of Hyporheic Flow Structure and Metabolic Pattern on Reach-scale Nutrient Uptake

    NASA Astrophysics Data System (ADS)

    Li, A.; Aubeneau, A. F.; Bolster, D.; Tank, J. L.; Packman, A. I.

    2015-12-01

    Co-injections of conservative tracers and nutrients are commonly used to assess net reach-scale nutrient transformation rates and benthic/hyporheic uptake parameters. However, little information is available on spatial metabolic patterns in the benthic and hyporheic regions. Based on observations from real systems, we used particle tracking simulations to explore the effects of localized metabolism on estimates of reach-scale nutrient uptake rates. Metabolism locally depletes nutrient concentrations relative to conservative tracers, causing their concentration profiles of injected nutrients and conservative tracers to diverge. At slow rates of hyporheic exchange relative to rates of metabolism, overall hyporheic nutrient uptake is limited by delivery from the stream, and effective reach-scale nutrient uptake parameters will be controlled by the hyporheic exchange rate. At high rates of hyporheic exchange relative to rates of metabolism, the injected tracer can propagate beyond regions of high microbial activity, which commonly occur near the streambed surface. In this case, the injected tracer may not adequately capture timescales of nutrient replenishment in the most bioactive regions. Reach-scale nutrients uptake rate increases with increasing heterogeneity in local metabolic patterns, altering the shape of breakthrough curves downstream. More observations of hyporheic rates and metabolic patterns are needed to understand how flow heterogeneity and reaction heterogeneity interact to control nutrient dynamics at reach-scale.

  18. Tracer tests in geothermal resource management

    NASA Astrophysics Data System (ADS)

    Axelsson, G.

    2013-05-01

    Geothermal reinjection involves injecting energy-depleted fluid back into geothermal systems, providing an effective mode of waste-water disposal as well as supplementary fluid recharge. Cooling of production boreholes is one of the main disadvantages associated with reinjection, however. Tracer testing is an important tool for reinjection studies because tracer tests actually have a predictive power since tracer transport is orders of magnitude faster than cold-front advancement around reinjection boreholes. A simple and efficient method of tracer test interpretation, assuming specific flow channels connecting reinjection and production boreholes, is available. It simulates tracer return profiles and estimates properties of the flow channels, which are consequently used for predicting the production borehole cooling. Numerous examples are available worldwide on the successful application of tracer tests in geothermal management, many involving the application of this interpretation technique. Tracer tests are also used for general subsurface hydrological studies in geothermal systems and for flow rate measurements in two-phase geothermal pipelines. The tracers most commonly used in geothermal applications are fluorescent dyes, chemical substances and radioactive isotopes. New temperature-resistant tracers have also been introduced and high-tech tracers are being considered.

  19. Structurally abnormal human autosomes

    SciTech Connect

    1993-12-31

    Chapter 25, discusses structurally abnormal human autosomes. This discussion includes: structurally abnormal chromosomes, chromosomal polymorphisms, pericentric inversions, paracentric inversions, deletions or partial monosomies, cri du chat (cat cry) syndrome, ring chromosomes, insertions, duplication or pure partial trisomy and mosaicism. 71 refs., 8 figs.

  20. Petroleum characterization by perfluorocarbon tracers

    SciTech Connect

    Senum, G.I.; Fajer, R.W. ); Harris, B.R. Jr. ); DeRose, W.E. ); Ottaviani, W.L. )

    1992-02-01

    Perfluorocarbon tracers (PFTs), a class of six compounds, were used to help characterize the Shallow Oil Zone (SOZ) reservoir at the Naval Petroleum Reserve in California (NPRC) at Elk Hills. The SOZ reservoir is undergoing a pilot gas injection program to assess the technical feasibility and economic viability of injecting gas into the SOZ for improved oil recovery. PFTs were utilized in the pilot gas injection to qualitatively assess the extent of the pilot gas injection so as to determine the degree of gas containment within the SOZ reservoir.

  1. Morphological abnormalities among lampreys

    USGS Publications Warehouse

    Manion, Patrick J.

    1967-01-01

    The experimental control of the sea lamprey (Petromyzon marinus) in the Great Lakes has required the collection of thousands of lampreys. Representatives of each life stage of the four species of the Lake Superior basin were examined for structural abnormalities. The most common aberration was the presence of additional tails. The accessory tails were always postanal and smaller than the normal tail. The point of origin varied; the extra tails occurred on dorsal, ventral, or lateral surfaces. Some of the extra tails were misshaped and curled, but others were normal in shape and pigment pattern. Other abnormalities in larval sea lampreys were malformed or twisted tails and bodies. The cause of the structural abnormalities is unknown. The presence of extra caudal fins could be genetically controlled, or be due to partial amputation or injury followed by abnormal regeneration. Few if any lampreys with structural abnormalities live to sexual maturity.

  2. Effects of submesoscale turbulence on ocean tracers

    NASA Astrophysics Data System (ADS)

    Smith, Katherine M.; Hamlington, Peter E.; Fox-Kemper, Baylor

    2016-01-01

    Ocean tracers such as carbon dioxide, nutrients, plankton, and oil advect, diffuse, and react primarily in the oceanic mixed layer where air-sea gas exchange occurs and light is plentiful for photosynthesis. There can be substantial heterogeneity in the spatial distributions of these tracers due to turbulent stirring, particularly in the submesoscale range where partly geostrophic fronts and eddies and small-scale three-dimensional turbulence are simultaneously active. In this study, a large eddy simulation spanning horizontal scales from 20 km down to 5 m is used to examine the effects of multiscale turbulent mixing on nonreactive passive ocean tracers from interior and sea-surface sources. The simulation includes the effects of both wave-driven Langmuir turbulence and submesoscale eddies, and tracers with different initial and boundary conditions are examined in order to understand the respective impacts of small-scale and submesoscale motions on tracer transport. Tracer properties are characterized using spatial fields and statistics, multiscale fluxes, and spectra, and the results detail how tracer mixing depends on air-sea tracer flux rate, tracer release depth, and flow regime. Although vertical fluxes of buoyancy by submesoscale eddies compete with mixing by Langmuir turbulence, vertical fluxes of tracers are often dominated by Langmuir turbulence, particularly for tracers that are released near the mixed-layer base or that dissolve rapidly through the surface, even in regions with pronounced submesoscale activity. Early in the evolution of some tracers, negative eddy diffusivities occur co-located with regions of negative potential vorticity, suggesting that symmetric instabilities or other submesoscale phenomenon may act to oppose turbulent mixing.

  3. Platelet monoamine uptake in relatives of patients with Huntington's chorea.

    PubMed Central

    Ehsanullah, R. S.; Turner, P.

    1981-01-01

    Uptake of dopamine and 5-hydroxytryptamine (5-HT) by the platelets of 25 symptom-free relatives of patients with established Huntington's chorea (HC) was not significantly different from that of control subjects. Platelet uptake of 5-HT in 3 subjects with early signs of the disease showed increased Km and Vmax values. Increased platelet uptake of 5-HT in patients with established HC was confirmed in a further 3 patients. It seems that this phenomenon appears with the clinical evidence of the disease. Further investigation of the nature of the platelet uptake abnormality may cast light on pathogenic factors in HC. PMID:6458032

  4. Organic anion uptake by hepatocytes.

    PubMed

    Wolkoff, Allan W

    2014-10-01

    Many of the compounds taken up by the liver are organic anions that circulate tightly bound to protein carriers such as albumin. The fenestrated sinusoidal endothelium of the liver permits these compounds to have access to hepatocytes. Studies to characterize hepatic uptake of organic anions through kinetic analyses, suggested that it was carrier-mediated. Attempts to identify specific transporters by biochemical approaches were largely unsuccessful and were replaced by studies that utilized expression cloning. These studies led to identification of the organic anion transport proteins (oatps), a family of 12 transmembrane domain glycoproteins that have broad and often overlapping substrate specificities. The oatps mediate Na(+)-independent organic anion uptake. Other studies identified a seven transmembrane domain glycoprotein, Na(+)/taurocholate transporting protein (ntcp) as mediating Na(+)-dependent uptake of bile acids as well as other organic anions. Although mutations or deficiencies of specific members of the oatp family have been associated with transport abnormalities, there have been no such reports for ntcp, and its physiologic role remains to be determined, although expression of ntcp in vitro recapitulates the characteristics of Na(+)-dependent bile acid transport that is seen in vivo. Both ntcp and oatps traffic between the cell surface and intracellular vesicular pools. These vesicles move through the cell on microtubules, using the microtubule based motors dynein and kinesins. Factors that regulate this motility are under study and may provide a unique mechanism that can alter the plasma membrane content of these transporters and consequently their accessibility to circulating ligands.

  5. EFFICIENT HYDROLOGICAL TRACER-TEST DESIGN (EHTD ...

    EPA Pesticide Factsheets

    Hydrological tracer testing is the most reliable diagnostic technique available for establishing flow trajectories and hydrologic connections and for determining basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test design can be difficult because of a lack of prior knowledge of the basic hydraulic and geometric parameters desired and the appropriate tracer mass to release. A new efficient hydrologic tracer-test design (EHTD) methodology has been developed that combines basic measured field parameters (e.g., discharge, distance, cross-sectional area) in functional relationships that describe solute-transport processes related to flow velocity and time of travel. The new method applies these initial estimates for time of travel and velocity to a hypothetical continuously stirred tank reactor as an analog for the hydrologic flow system to develop initial estimates for tracer concentration and axial dispersion, based on a preset average tracer concentration. Root determination of the one-dimensional advection-dispersion equation (ADE) using the preset average tracer concentration then provides a theoretical basis for an estimate of necessary tracer mass.Application of the predicted tracer mass with the hydraulic and geometric parameters in the ADE allows for an approximation of initial sample-collection time and subsequent sample-collection frequency where a maximum of 65 samples were determined to

  6. Doublet Tracer Testing in Klamath Falls, Oregon

    SciTech Connect

    Gudmundsson, J.S.; Johnson, S.E.; Horne, R.N.; Jackson, P.B.; Culver, G.G.

    1983-12-15

    A tracer test was carried out in a geothermal doublet system to study the injection behavior of a developed reservoir known to be fractured. The doublet produces about 320 gpm of 160 F water that is used for space heating and then injected; the wells are spaced 250 ft apart. Tracer breakthrough was observed in 2 hours and 45 minutes in the production well, indicating fracture flow. However, the tracer concentrations were low and indicated porous media flow; the tracers mixed with a reservoir volume much larger than a fracture.

  7. Diffuse FDG renal uptake in lymphoma.

    PubMed

    Navalkissoor, Shaunak; Szyszko, Teresa; Gnanasegaran, Gopinath; Nunan, Thomas

    2010-10-01

    In patients presenting with acute renal failure and known/suspected lymphoma, the diagnosis of diffuse renal involvement is important, as there is potential for rapid resolution with chemotherapy. Although FDG is excreted through the kidneys and focal renal disease may be difficult to identify, diffuse renal FDG is more easily recognized and is always abnormal. We report a patient presenting with acute renal failure and suspected lymphoma. F-18 FDG PET/CT study demonstrated diffuse increased FDG uptake in bilaterally enlarged kidneys. Following 1 cycle of chemotherapy, the renal function normalized. An interim F-18 FDG PET/CT demonstrated normal size and FDG uptake within both kidneys.

  8. Tracer-Test Planning Using the Efficient Hydrologic Tracer-Test Design (Ehtd) Program (2003)

    EPA Science Inventory

    Hydrological tracer testing is the most reliable diagnostic technique available for establishing flow trajectories and hydrologic connections and for determining basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test ...

  9. Balloon tracer for atmospheric pollutants

    SciTech Connect

    Lichfield, E.W.; Ivey, M.D.; Zak, B.D.; Church, H.W.

    1985-01-01

    An operational prototype of the Balloon Tracer was developed and described. This prototype was designed to be capable of meeting all of the desired specifications for the Balloon Tracer. Its buoyancy adjustment subsystem is shown. Three Gilian instrument pumps operating in parallel provide a flow of about 12 litres per minute, depending upon backpressure. The miniature Klippard mechanical valves are actuated by a servo mechanism which only requires power when the state of the valves is being changed. The balloon itself for the operational prototype is just under 3 meters in diameter. A block diagram of the operational prototype payload measures ambient pressure, temperature, and humidity obtained from AIR which outputs its data in ASCII format. The vertical anemometer, which has a measured starting speed of under 2 cm/s, makes use of a Gill styrofoam propeller and a Spaulding Instruments rotation sendor. The command decoder is built around a chip developed originally for remote control television tuners. The command receiver operating on 13.8035 MHz was developed and built by Hock Engineering. The Argos transmitter is a Telonics platform transmitter terminal. The heart of the control system is an Intel 8052AH BASIC microcomputer with both random access and read only memory.

  10. The electromotor system of the electric eel investigated with horseradish peroxidase as a retrograde tracer.

    PubMed

    Bennett, M V; Sandri, C

    1989-05-29

    The electromotor system of the electric eel, Electrophorus electricus, was studied by injection of horseradish peroxidase as a retrograde tracer. The electromotor neurons, which innervate the electrocytes, comprise a midline nucleus, largely dorsal to the spinal canal. Spinal motoneurons lie ventrolaterally. The electromotor and skeletal motor neuron populations correspond to the acetylcholinesterase-negative and -positive cells previously described. The medullary relay neurons were labeled following HRP injection into the spinal cord at a level where electromotor neurons occurred, but not after injection into the cord in the abdominal region rostral to these cells. Other medullary neurons, presumably bulbospinal motor fibers, were labeled after both levels of spinal cord injection. The results suggest that these axosomatic synapses, which are electrically transmitting but morphologically mixed, take up retrograde tracers in a manner similar to chemical synapses and that tracer uptake is at least largely at terminal regions.

  11. Tracers of Past Ocean Circulation

    NASA Astrophysics Data System (ADS)

    Lynch-Stieglitz, J.

    2003-12-01

    Information about how the ocean circulated during the past is useful in understanding changes in ocean and atmospheric chemistry, changes in the fluxes of heat and freshwater between the ocean and atmosphere, and changes in global wind patterns. The circulation of surface waters in the ocean leaves an imprint on sea surface temperature, and is also inextricably linked to the patterns of oceanic productivity. Much valuable information about past ocean circulation has been inferred from reconstructions of surface ocean temperature and productivity, which are covered in separate chapters. Here the focus is on the geochemical tracers that are used to infer the flow patterns and mixing of subsurface water masses.Several decades ago it was realized that chemistry of the shells of benthic foraminifera (carbon isotope and Cd/Ca ratios) carried an imprint of the nutrient content of deep-water masses (Shackleton, 1977; Broecker, 1982; Boyle, 1981). This led rapidly to the recognition that the water masses in the Atlantic Ocean were arrayed differently during the last glacial maximum than they are today, and the hypothesis that the glacial arrangement reflected a diminished contribution of low-nutrient North Atlantic deep water (NADW) ( Curry and Lohmann, 1982; Boyle and Keigwin, 1982). More detailed spatial reconstructions indicated a shallow nutrient-depleted water mass overlying a more nutrient-rich water mass in the glacial Atlantic. These findings spurred advances not only in geochemistry but in oceanography and climatology, as workers in these fields attempted to simulate the inferred glacial circulation patterns and assess the vulnerability of the modern ocean circulation to changes such as observed for the last ice age.While the nutrient distributions in the glacial Atlantic Ocean were consistent with a diminished flow of NADW, they also could have reflected an increase in inflow from the South Atlantic and/or a shallower yet undiminished deep-water mass. Clearly

  12. Evaluation of [123I]isopropyliodoamphetamine as a tracer for local cerebral blood flow using direct autoradiographic comparison.

    PubMed

    Lear, J L; Ackermann, R F; Kameyama, M; Kuhl, D E

    1982-01-01

    We investigated [123I]isopropyliodoamphetamine (IMP) for potential use in the autoradiographic determination of local cerebral blood flow (LCBF) in animals. The technique of direct autoradiographic comparison, derived from double radionuclide autoradiography, was used to compare the simultaneous uptakes of IMP and [14C]iodoantipyrine (IAP), a reference tracer, in awake and anesthetized rats. This new technique offers several advantages over the previously developed methods of comparing tracers, brain uptake index and first pass extraction ratio. These include the avoidance of disrupting normal cerebral blood-brain tracer exchange and the ability to compare uptakes at substructural levels, whereas the other methods are limited to larger areas. Mean values of LCBF obtained with IMP agreed closely with those using IAP, from 20 to 300 ml/100 g/min. Because IMP was found to have an extremely high effective brain:blood partition coefficient, approximately 25:1, a linear uptake tracer model could be used for IMP yielding more precise values than could IAP for LCBF values above 150. IMP was found to measure choroid plexus flows much more accurately than IAP, values being greater than 500 for IMP compared to approximately 200 for IAP. Because the mechanism of the extremely high partition coefficient of IMP is not yet defined, however, care must be used in measuring LCBF with IMP where the trapping mechanisms of normal vessels may be disrupted.

  13. Evaluation of (/sup 123/I)isopropyliodoamphetamine as a tracer for local cerebral blood flow using direct autoradiographic comparison

    SciTech Connect

    Lear, J.L.; Ackermann, R.F.; Kameyama, M.; Kuhl, D.E.

    1982-01-01

    We investigated (/sup 123/I)isopropyliodoamphetamine (IMP) for potential use in the autoradiographic determination of local cerebral blood flow (LCBF) in animals. The technique of direct autoradiographic comparison, derived from double radionuclide autoradiography, was used to compare the simultaneous uptakes of IMP and (/sup 14/C)iodoantipyrine (IAP), a reference tracer, in awake and anesthetized rats. This new technique offers several advantages over the previously developed methods of comparing tracers, brain uptake index and first pass extraction ratio. These include the avoidance of disrupting normal cerebral blood-brain tracer exchange and the ability to compare uptakes at substructural levels, whereas the other methods are limited to larger areas. Mean values of LCBF obtained with IMP agreed closely with those using IAP, from 20 to 300 ml/100 g/min. Because IMP was found to have an extremely high effective brain:blood partition coefficient, approximately 25:1, a linear uptake tracer model could be used for IMP yielding more precise values than could IAP for LCBF values above 150. IMP was found to measure choroid plexus flows much more accurately than IAP, values being greater than 500 for IMP compared to approximately 200 for IAP. Because the mechanism of the extremely high partition coefficient of IMP is not yet defined, however, care must be used in measuring LCBF with IMP where the trapping mechanisms of normal vessels may be disrupted.

  14. Kinetic Modeling of the Tau PET Tracer 18F-AV-1451 in Human Healthy Volunteers and Alzheimer's Disease Subjects.

    PubMed

    Barret, Olivier; Alagille, David; Sanabria, Sandra; Comley, Robert A; Weimer, Robby M; Borroni, Edilio; Mintun, Mark; Seneca, Nicholas; Papin, Caroline; Morley, Thomas; Marek, Ken; Seibyl, John P; Tamagnan, Gilles D; Jennings, Danna

    2016-12-01

    (18)F-AV-1451 is currently the most widely used of several experimental tau PET tracers. The objective of this study was to evaluate (18)F-AV-1451 binding with full kinetic analysis using a metabolite corrected arterial input function, and to compare parameters derived from kinetic analysis with standardized uptake value ratio (SUVR) calculated over different imaging time intervals.

  15. Using ocean tracers to reduce uncertainties about ocean diapycnal mixing and model projections

    NASA Astrophysics Data System (ADS)

    Goes, M. P.; Urban, N.; Keller, K.; Schmittner, A.; Tonkonojenkov, R.; Haran, M.

    2010-12-01

    Current projections of the oceanic response to anthropogenic climate forcings are uncertain. Two key sources of these uncertainties are (i) structural errors in current Earth system models and (ii) imperfect knowledge of model parameters. Ocean tracers observations have the potential to reduce these uncertainties. Previous studies typically consider each tracer separately, neglect potentially important statistical properties of the system, or use methods that impose rather daunting computational demands. Here we extend and improve upon a recently developed approach using horizontally averaged vertical profiles of chlorofluorocarbon (CFC-11), radiocarbon (DC14), and temperature (T) observations to reduce model parametric and structural uncertainties. Our method estimates a joint probability density function, which considers cross-tracer correlations and spatial autocorrelations of the errors. We illustrate this method by estimating two model parameters related to the vertical diffusivity, the background vertical diffusivity and the upper Southern Ocean mixing. We show that enhancing the upper Southern Ocean mixing in the model improves the representations of ocean tracers, as well as improves hindcasts of the Atlantic Meridional Overturning Circulation (AMOC) and Ocean Carbon uptake. The most probable value of the background vertical diffusivity in the pelagic pycnocline is between 0.1-0.2 cm2/s. According to the statistical method, observations of DC14 reduce the uncertainty about the background vertical diffusivity the most followed by CFC-11 and T. Using all three tracers jointly reduces the model uncertainty by 40%, more than each tracer individually. Given several important caveats, we illustrate how the reduced model parametric uncertainty improves probabilistic projections of the AMOC and Ocean Carbon uptake.

  16. Tracers for Characterizing Enhanced Geothermal Systems

    SciTech Connect

    Karen Wright; George Redden; Carl D. Palmer; Harry Rollins; Mark Stone; Mason Harrup; Laurence C. Hull

    2010-02-01

    Information about the times of thermal breakthrough and subsequent rates of thermal drawdown in enhanced geothermal systems (EGS) is necessary for reservoir management, designing fracture stimulation and well drilling programs, and forecasting economic return. Thermal breakthrough in heterogeneous porous media can be estimated using conservative tracers and assumptions about heat transfer rates; however, tracers that undergo temperature-dependent changes can provide more detailed information about the thermal profile along the flow path through the reservoir. To be effectively applied, the thermal reaction rates of such temperature sensitive traces must be well characterized for the range of conditions that exist in geothermal systems. Reactive tracers proposed in the literature include benzoic and carboxylic acids (Adams) and organic esters and amides (Robinson et al.); however, the practical temperature range over which these tracers can be applied (100-275°C) is somewhat limited. Further, for organic esters and amides, little is known about their sorption to the reservoir matrix and how such reactions impact data interpretation. Another approach involves tracers where the reference condition is internal to the tracer itself. Two examples are: 1) racemization of polymeric amino acids, and 2) mineral thermoluminescence. In these cases internal ratios of states are measured rather than extents of degradation and mass loss. Racemization of poly-L-lactic acid (for example) is temperature sensitive and therefore can be used as a temperature-recording tracer depending on the rates of racemization and stability of the amino acids. Heat-induced quenching of thermoluminescence of pre-irradiated LiF can also be used. To protect the tracers from alterations (extraneous reactions, dissolution) in geothermal environments we are encapsulating the tracers in core-shell colloidal structures that will subsequently be tested for their ability to be transported and to protect the

  17. "Jeopardy" in Abnormal Psychology.

    ERIC Educational Resources Information Center

    Keutzer, Carolin S.

    1993-01-01

    Describes the use of the board game, Jeopardy, in a college level abnormal psychology course. Finds increased student interaction and improved application of information. Reports generally favorable student evaluation of the technique. (CFR)

  18. Practical considerations in the use of stable isotope labelled compounds as tracers in clinical studies.

    PubMed

    Thompson, G N; Pacy, P J; Ford, G C; Halliday, D

    1989-05-01

    Increasingly widespread usage of stable isotope tracers to aid clinical diagnosis and support basic research has stemmed from both advances in mass spectrometry and the availability of competitively priced labelled compounds. Stable isotopes have been used generally to investigate normal and abnormal metabolic pathways, to estimate energy expenditure and body composition and to quantitate substrate flux and oxidation rates. Despite the fact that the underlying principles relating to the use of stable isotopes for in vivo studies are straightforward, careful consideration must be given to all aspects of human studies. This review highlights some of these, including choice of label and tracer molecule, mode of tracer administration and sampling site, analytical instrumentation, interpretation of data and ethical constraints.

  19. USING TRACERS TO DESCRIBE NAPL HETEROGENEITY

    EPA Science Inventory

    Tracers are frequently used to estimate both the average travel time for water flow through the tracer swept volume and NAPL saturation. The same data can be used to develop a statistical distribution describing the hydraulic conductivity in the sept volume and a possible distri...

  20. Diel rhythmicity in amino acid uptake by Prochlorococcus.

    PubMed

    Mary, Isabelle; Garczarek, Laurence; Tarran, Glen A; Kolowrat, Christian; Terry, Matthew J; Scanlan, David J; Burkill, Peter H; Zubkov, Mikhail V

    2008-08-01

    The marine cyanobacterium Prochlorococcus, the most abundant phototrophic organism on Earth, numerically dominates the phytoplankton in nitrogen (N)-depleted oceanic gyres. Alongside inorganic N sources such as nitrite and ammonium, natural populations of this genus also acquire organic N, specifically amino acids. Here, we investigated using isotopic tracer and flow cytometric cell sorting techniques whether amino acid uptake by Prochlorococcus is subject to a diel rhythmicity, and if so, whether this was linked to a specific cell cycle stage. We observed, in contrast to diurnally similar methionine uptake rates by Synechococcus cells, obvious diurnal rhythms in methionine uptake by Prochlorococcus cells in the tropical Atlantic. These rhythms were confirmed using reproducible cyclostat experiments with a light-synchronized axenic Prochlorococcus (PCC9511 strain) culture and (35)S-methionine and (3)H-leucine tracers. Cells acquired the tracers at lower rates around dawn and higher rates around dusk despite >10(4) times higher concentration of ammonium in the medium, presumably because amino acids can be directly incorporated into protein. Leucine uptake rates by cells in the S+G(2) cell cycle stage were consistently 2.2 times higher than those of cells at the G(1) stage. Furthermore, S+G(2) cells upregulated amino acid uptake 3.5 times from dawn to dusk to boost protein synthesis prior to cell division. Because Prochlorococcus populations can account from 13% at midday to 42% at dusk of total microbial uptake of methionine and probably of other amino acids in N-depleted oceanic waters, this genus exerts diurnally variable, strong competitive pressure on other bacterioplankton populations.

  1. Effect of tracer buoyancy on tracer experiments conducted in fractured crystalline bedrock

    NASA Astrophysics Data System (ADS)

    Becker, Matthew W.

    2003-02-01

    Tracer buoyancy has been shown to influence breakthrough from two-well tracer experiments conducted in porous media. Two-well tracer experiments are presented from fractured crystalline bedrock, in which the specific gravity of the tracer injectate varied from 1.0002 to 1.0133. Under the forced hydraulic conditions imposed, no difference in breakthrough was noted for the three experiments. These results show that even relatively dense tracer injectate solutions may have an insignificant effect on breakthrough when imposed gradients are sufficiently large.

  2. The Art of Tomographic Tracer Tests

    NASA Astrophysics Data System (ADS)

    Cirpka, O. A.; Leven, C.; Doro, K. O.; Sanchez-Leon, E. E.

    2015-12-01

    In tracer tomography several tracer tests are performed within an aquifer and breakthrough curves are observed at multiple observation points. In the analysis, hydraulic conductivity is estimated as spatially variable, 3-D field subject to some smoothness constraint. Coupled flow and transport models using this conductivity fields are requested to meet observed tracer data. The approach can be combined with hydraulic tomography.We have performed hydraulic-tomography and tracer-tomography tests using heat and fluorescein as tracers at a field site close to Tübingen, Germany. The aquifer consists of 8-9m alluvials sands and gravels overlain by 1-2m alluvial fines. The hydraulic setup consists of a forced flow field between an injection/extraction well couple, embedded in the forced flow field of another well couple. By turning injection to extraction wells, and vice versa, two different flow fields were considered. Injection wells were separated into several sections by packers, and water was injected into each section proportional to its transmissivity. The water injected into one of the sections contained the tracer. Multi-level observation wells were equiped with thermometers (for heat-tracer tests), on-line fluoremeters (for teh dye tracers), and pressure transducers. Processing of the breakthrough curves included data cleaning, non-parametric deconvolution, and calculation of temperal moments of the estimated transfer functions.The joint inversion of hydraulic-head measurements and temporal moments of heat-tracer transfer functions was done by the quasi-linear geostatistical approach on a computing cluster. As alternative, we directly invert the time series (without temporal moments) by Ensemble-Kalman filtering.The high diffusion coefficient of temperature diminishes the penetration of the heat-tracer into the aquifer, which can partially be compensated by reverting the flow field and repeating the tracer tests. In tests with fluorscent tracers the signal

  3. Late effects of abdominal radiation on intestinal uptake of nutrients

    SciTech Connect

    Thomson, A.B.; Cheeseman, C.I.; Walker, K.

    1986-09-01

    The late effects of variable doses of abdominal irradiation on in vitro jejunal uptake were examined. The uptake of glucose, galactose, cholic acid, medium-chain length fatty acids, and decanol was studied 6 and 33 weeks following 300, 600, or 900 cGy abdominal irradiation. The intestinal morphological characteristics were similar 6 and 33 weeks after radiation. The uptake of cholic acid was unaffected by abdominal irradiation, but for glucose, galactose, and four fatty acids the direction and magnitude of the changes in uptake were influenced by the dose of irradiation and by the interval following exposure. The greater uptake of decanol at 6 weeks but lower uptake of decanol at 33 weeks reflected changes in the resistance of the intestinal unstirred water layer. These absorption changes suggest that the intestine may not be capable of correcting the transport abnormalities arising from sublethal doses of abdominal irradiation.

  4. Does FDG uptake measure proliferative activity of human cancer cells? In vitro comparison with DNA flow cytometry and tritiated thymidine uptake.

    PubMed

    Higashi, K; Clavo, A C; Wahl, R L

    1993-03-01

    The relationship between 3H-2-fluoro-2-deoxy-D-glucose (FDG) uptake and the proliferative rate of a human ovarian adenocarcinoma cell line (HTB77IP3) was examined in vitro. HTB77IP3 cells were plated and allowed to grow through lag, exponential and plateau phases. Proliferative rate assessed by DNA flow cytometry and 3H-thymidine incorporation was highest in the lag phase and fell significantly as the cells progressed from the exponential through plateau phases. By DNA flow cytometry, the proliferation index (% of S+G2/M phase cells) fell from 65% to 23%. Thymidine uptake per cell also declined, by 82%, from lag to plateau phase. By contrast, 3H-FDG uptake per cell was largely unchanged as the cells progressed through the cell growth cycle. Total 3H-FDG uptake was strongly correlated with the number of viable cancer cells present (r = 0.957). Total thymidine uptake, however, substantially underestimated the number of viable cancer cells present. These in vitro differences in tracer uptake suggest that in this adenocarcinoma cell line, FDG measures a substantially different parameter (viable cell number) than thymidine (proliferative rate) and that these differences may result in disparate findings on PET imaging of cancers using these two tracers. Our data for this in vitro system indicate that FDG uptake does not relate to the proliferative activity of cancer cells. However, FDG uptake is strongly related to the number of viable tumor cells.

  5. Using Tracer Technology to Characterize Contaminated Pipelines

    SciTech Connect

    Maresca, Joseph, W., Jr., Ph.D.; Bratton, Wesley, L., Ph.D., P.E.; Dickerson, Wilhelmina; Hales, Rochelle

    2005-12-30

    The Pipeline Characterization Using Tracers (PCUT) technique uses conservative and partitioning, reactive or other interactive tracers to remotely determine the amount of contaminant within a run of piping or ductwork. The PCUT system was motivated by a method that has been successfully used to characterize subsurface soil contaminants and is similar in operation to that of a gas chromatography column. By injecting a ?slug? of both conservative and partitioning tracers at one end (or section) of the piping and measuring the time history of the concentration of the tracers at the other end (or another section) of the pipe, the presence, location, and amount of contaminant within the pipe or duct can be determined. The tracers are transported along the pipe or duct by a gas flow field, typically air or nitrogen, which has a velocity that is slow enough so that the partitioning tracer has time to interact with the contaminant before the tracer slug completely passes over the contaminate region. PCUT not only identifies the presence of contamination, it also can locate the contamination along the pipeline and quantify the amount of residual. PCUT can be used in support of deactivation and decommissioning (D&D) of piping and ducts that may have been contaminated with hazardous chemicals such as chlorinated solvents, petroleum products, radioactive materials, or heavy metals, such as mercury.

  6. Tracer design for magnetic particle imaging (invited)

    PubMed Central

    Ferguson, R. Matthew; Khandhar, Amit P.; Krishnan, Kannan M.

    2012-01-01

    Magnetic particle imaging (MPI) uses safe iron oxide nanoparticle tracers to offer fundamentally new capabilities for medical imaging, in applications as vascular imaging and ultra-sensitive cancer therapeutics. MPI is perhaps the first medical imaging platform to intrinsically exploit nanoscale material properties. MPI tracers contain magnetic nanoparticles whose tunable, size-dependent magnetic properties can be optimized by selecting a particular particle size and narrow size-distribution. In this paper we present experimental MPI measurements acquired using a homemade MPI magnetometer: a zero-dimensional MPI imaging system designed to characterize tracer performance by measuring the derivative of the time-varying tracer magnetization, M’(H(t)), at a driving frequency of 25 kHz. We show that MPI performance is optimized by selecting phase-pure magnetite tracers of a particular size and narrow size distribution; in this work, tracers with 20 nm median diameter, log-normal distribution shape parameter, σv, equal to 0.26, and hydrodynamic diameter equal to 30 nm showed the best performance. Furthermore, these optimized MPI tracers show 4 × greater signal intensity (measured at the third harmonic) and 20% better spatial resolution compared with commercial nanoparticles developed for MRI. PMID:22434939

  7. Wanted: Scalable Tracers for Diffusion Measurements

    PubMed Central

    2015-01-01

    Scalable tracers are potentially a useful tool to examine diffusion mechanisms and to predict diffusion coefficients, particularly for hindered diffusion in complex, heterogeneous, or crowded systems. Scalable tracers are defined as a series of tracers varying in size but with the same shape, structure, surface chemistry, deformability, and diffusion mechanism. Both chemical homology and constant dynamics are required. In particular, branching must not vary with size, and there must be no transition between ordinary diffusion and reptation. Measurements using scalable tracers yield the mean diffusion coefficient as a function of size alone; measurements using nonscalable tracers yield the variation due to differences in the other properties. Candidate scalable tracers are discussed for two-dimensional (2D) diffusion in membranes and three-dimensional diffusion in aqueous solutions. Correlations to predict the mean diffusion coefficient of globular biomolecules from molecular mass are reviewed briefly. Specific suggestions for the 3D case include the use of synthetic dendrimers or random hyperbranched polymers instead of dextran and the use of core–shell quantum dots. Another useful tool would be a series of scalable tracers varying in deformability alone, prepared by varying the density of crosslinking in a polymer to make say “reinforced Ficoll” or “reinforced hyperbranched polyglycerol.” PMID:25319586

  8. Wanted: scalable tracers for diffusion measurements.

    PubMed

    Saxton, Michael J

    2014-11-13

    Scalable tracers are potentially a useful tool to examine diffusion mechanisms and to predict diffusion coefficients, particularly for hindered diffusion in complex, heterogeneous, or crowded systems. Scalable tracers are defined as a series of tracers varying in size but with the same shape, structure, surface chemistry, deformability, and diffusion mechanism. Both chemical homology and constant dynamics are required. In particular, branching must not vary with size, and there must be no transition between ordinary diffusion and reptation. Measurements using scalable tracers yield the mean diffusion coefficient as a function of size alone; measurements using nonscalable tracers yield the variation due to differences in the other properties. Candidate scalable tracers are discussed for two-dimensional (2D) diffusion in membranes and three-dimensional diffusion in aqueous solutions. Correlations to predict the mean diffusion coefficient of globular biomolecules from molecular mass are reviewed briefly. Specific suggestions for the 3D case include the use of synthetic dendrimers or random hyperbranched polymers instead of dextran and the use of core-shell quantum dots. Another useful tool would be a series of scalable tracers varying in deformability alone, prepared by varying the density of crosslinking in a polymer to make say "reinforced Ficoll" or "reinforced hyperbranched polyglycerol."

  9. Tracer Developments: Results of Experimental Studies

    SciTech Connect

    Adams, M.C.; Ahn, J.H.; Bentley, H.; Moore, J.N.; Veggeberg, S.

    1986-01-21

    Tracers can be used to monitor the movement of groundwaters and geothermal fluids and they can be used as a reference to quantify changes in fluid chemistry as a result of injection. Despite their potential importance to the geothermal operator, very few tracers are presently available and of those that are, little is known about their stability or behavior at the elevated temperatures that typify resources capable of electric power generation. During the past two years the University of Utah Research Institute has been involved in tracer research and testing, largely through the DOE Injection Research Program. The purpose of this paper is to summarize the results of these laboratory and field investigations.

  10. Tracking groundwater with fluoride tracers

    SciTech Connect

    Goldberg, S.P.; Carey, P.J.; Fitzsimmons, J.H.

    1995-10-01

    A municipality on Long Island, NY, owns and operates a solid waste landfill that is currently affecting groundwater quality. Specifically, groundwater monitoring in wells downgradient from the facility indicates the presence of organic and inorganic constituents in excess of New York state groundwater quality standards and guidance values. The municipality wishes to expand its existing facility by constructing a new cell adjacent to the old unlined facility. The new cell will incorporate state-of-the-art landfill design. A double-composite baseliner system--mandated by the New York State Department of Environmental Conservation (NYSDEC)--will be constructed to minimize the potential for leakage of leachate into the groundwater system. The downgradient groundwater flow paths from the existing and the proposed facility will overlap. As such, using conventional monitoring approaches, differentiating known groundwater quality impacts from the existing facility with potential impacts from the new cell could be extremely difficult. To consider the application for the landfill expansion, NYSDEC requested that a study be conducted to determine whether the incorporation of a tracer into the liner design for the new cell could help to differentiate potential future water quality impacts from those impacts presently exerted by the existing landfill.

  11. Relationship of sup(99m)Tc-MDP uptake to regional osseous circulation in skeletally immature and mature dogs

    SciTech Connect

    McKinstry, P.; Schnitzer, J.E.; Light, T.R.; Ogden, J.A.; Hoffer, P.

    1982-05-01

    Uptake of intravenously injected sup(99m)Tc-MDP in multiple regions of healthy skeletally immature and mature dogs was correlated with regional chondro-osseous blood flow determined by radioactively labeled microspheres. Compared to the microsphere distribution, the distribution of sup(99m)Tc-MDP indicated that blood flow is an important, but not exclusive, factor in the uptake of bone-seeking tracers. Other factors such as the affinity of the tracer for the various types of chondro-osseous tissues must also affect tracer uptake. A measure of the relative affinity of sup(99m)Tc-MDP for bone was derived by the ratio of the percentage of tracer uptake to the percentage of blood flow. The juxta-ephyseal region demonstrated the greatest affinity for the tracer, followed in decreasing affinity, by the cortical bone, epiphyseal cartilage, trabecular bone of the metaphysis and secondary ossification center, and marrow space. Within the spongiosa, affinity generally increased as the proportion of osseous trabeculae relative to marrow space increased. sup(99m)Tc-MDP uptake is disproportionately increased in areas of active bone growth and remodeling where the surface area of hydroxyapatite crystals available for adsorption is probably highest.

  12. [The relativity of abnormity].

    PubMed

    Nilson, Annika

    2006-01-01

    In the late 19th century and in the beginning of the 20th century, mental diseases and abnormal behavior was considered to be a great danger to culture and society. "Degeneration" was the buzzword of the time, used and misused by artists and scientists alike. At the same time, some scientists saw abnormity as the key to unlock the mysteries of the ordinary mind. Naturalistic curiosity left Pandoras box open when religion declined in Darwins wake. Two swedish scientists, the physician Bror Gadelius (1862-1938) and his friend the philosopher Axel Herrlin (1870-1937), inspired by the French psychologist Theodule Ribots (1839-1916) "psychology without a soul", denied all fixed demarcation lines between abnormity and normality. All humans are natures creatures ruled by physiological laws, not ruled by God or convention. Even ordinary morality was considered to be an utterly backward explanation and guideline for complex human behavior. Different forms of therapy, not various kinds of penalties for wicked and disturbing behavior, are the now the solution for lots of people, "normal" as well as "abnormal". Psychiatry is expanding.

  13. Abnormalities of gonadal differentiation.

    PubMed

    Berkovitz, G D; Seeherunvong, T

    1998-04-01

    Gonadal differentiation involves a complex interplay of developmental pathways. The sex determining region Y (SRY) gene plays a key role in testis determination, but its interaction with other genes is less well understood. Abnormalities of gonadal differentiation result in a range of clinical problems. 46,XY complete gonadal dysgenesis is defined by an absence of testis determination. Subjects have female external genitalia and come to clinical attention because of delayed puberty. Individuals with 46,XY partial gonadal dysgenesis usually present in the newborn period for the valuation of ambiguous genitalia. Gonadal histology always shows an abnormality of seminiferous tubule formation. A diagnosis of 46,XY true hermaphroditism is made if the gonads contain well-formed testicular and ovarian elements. Despite the pivotal role of the SRY gene in testis development, mutations of SRY are unusual in subjects with a 46,XY karyotype and abnormal gonadal development. 46,XX maleness is defined by testis determination in an individual with a 46,XX karyotype. Most affected individuals have a phenotype similar to that of Klinefelter syndrome. In contrast, subjects with 46,XX true hermaphroditism usually present with ambiguous genitalia. The majority of subjects with 46,XX maleness have Y sequences including SRY in genomic DNA. However, only rare subjects with 46,XX true hermaphroditism have translocated sequences encoding SRY. Mosaicism and chimaerism involving the Y chromosome can also be associated with abnormal gonadal development. However, the vast majority of subjects with 45,X/46,XY mosaicism have normal testes and normal male external genitalia.

  14. Improved tumor identification using dual tracer molecular imaging in fluorescence guided brain surgery

    NASA Astrophysics Data System (ADS)

    Xu, Xiaochun; Torres, Veronica; Straus, David; Brey, Eric M.; Byrne, Richard W.; Tichauer, Kenneth M.

    2015-03-01

    Brain tumors represent a leading cause of cancer death for people under the age of 40 and the probability complete surgical resection of brain tumors remains low owing to the invasive nature of these tumors and the consequences of damaging healthy brain tissue. Molecular imaging is an emerging approach that has the potential to improve the ability for surgeons to correctly discriminate between healthy and cancerous tissue; however, conventional molecular imaging approaches in brain suffer from significant background signal in healthy tissue or an inability target more invasive sections of the tumor. This work presents initial studies investigating the ability of novel dual-tracer molecular imaging strategies to be used to overcome the major limitations of conventional "single-tracer" molecular imaging. The approach is evaluated in simulations and in an in vivo mice study with animals inoculated orthotopically using fluorescent human glioma cells. An epidermal growth factor receptor (EGFR) targeted Affibody-fluorescent marker was employed as a targeted imaging agent, and the suitability of various FDA approved untargeted fluorescent tracers (e.g. fluorescein & indocyanine green) were evaluated in terms of their ability to account for nonspecific uptake and retention of the targeted imaging agent. Signal-to-background ratio was used to measure and compare the amount of reporter in the tissue between targeted and untargeted tracer. The initial findings suggest that FDA-approved fluorescent imaging agents are ill-suited to act as untargeted imaging agents for dual-tracer fluorescent guided brain surgery as they suffer from poor delivery to the healthy brain tissue and therefore cannot be used to identify nonspecific vs. specific uptake of the targeted imaging agent where current surgery is most limited.

  15. Lung uptake on Tc-99m albumin colloid liver spleen scan and on Ga-67 scan in angiotropic lymphoma

    SciTech Connect

    Kacki, M.H.; Joyce, J.M.; Coupal, J.J.; Ryo, U.Y. )

    1990-03-01

    Lung uptake of Tc-99m sulfur colloid has been reported in various hepatic and extrahepatic diseases, and lung uptake of gallium-67 may occur in patients with various interstitial lung disease without radiographic abnormality. This may be the first case of Tc-99m albumin colloid and Ga-67 lung uptake in a patient with angiotropic lymphoma of the liver, spleen, and uterus.

  16. Monitoring High Velocity Salt Tracer via 4D Electrical Resistivity Tomography - Possibility for Salt Tracer Tomography

    NASA Astrophysics Data System (ADS)

    Doro, K. O.; Cirpka, O. A.; Patzelt, A.; Leven, C.

    2014-12-01

    Hydrogeological testing in a tomographic sequence as shown by the use of hydraulic tomography, allows an improvement of the spatial resolution of subsurface parameters. In this regard, recent studies show increasing interest in tracer tomography which involves sequential and spatially separated tracer injections and the measurement of their corresponding tracer breakthrough at different locations and depths. Such concentration measurements however require large experimental efforts and can be simplified by geophysical tracer monitoring techniques such as electrical resistivity. In this study, we present the use of 4-D, cross-hole electrical resistivity tomography (ERT) for monitoring salt tracer experiments in high velocity flow fields. For our study, we utilized a set up that enables the conduction of salt tracer experiments with complete recovery within 84 hours over a transport distance of 16 m. This allows the repetition of the experiments with different injection depths for a tomographic salt tracer testing. For ERT monitoring, we designed modular borehole electrodes for repeated usage in a flexible manner. We also assess the use of a high speed resistivity data acquisition mode for field scale tracer monitoring ensuring high spatial and temporal resolution without sacrificing data accuracy. We applied our approach at the Lauswiesen test site, Tübingen, Germany. In our 10 m × 10 m tracer monitoring domain with 16 borehole electrodes, we acquired 4650 data points in less than 18 minutes for each monitoring cycle. Inversion results show that the tracer could be successfully imaged using this approach. The results show that repeated salt tracer tests can be efficiently monitored at a high resolution with ERT which gives the possibility for salt tracer tomography at field scale. Our results also provide a data base for extending current hydrogeophysical inversion approaches to field scale data.

  17. Heritable bovine fetal abnormalities.

    PubMed

    Whitlock, B K; Kaiser, L; Maxwell, H S

    2008-08-01

    The etiologies for congenital bovine fetal anomalies can be divided into heritable, toxic, nutritional, and infectious categories. Although uncommon in most herds, inherited congenital anomalies are probably present in all breeds of cattle and propagated as a result of specific trait selection that inadvertently results in propagation of the defect. In some herds, the occurrence of inherited anomalies has become frequent, and economically important. Anomalous traits can affect animals in a range of ways, some being lethal or requiring euthanasia on humane grounds, others altering structure, function, or performance of affected animals. Veterinary practitioners should be aware of the potential for inherited defects, and be prepared to investigate and report animals exhibiting abnormal characteristics. This review will discuss the morphologic characteristics, mode of inheritance, breeding lines affected, and the availability of genetic testing for selected heritable bovine fetal abnormalities.

  18. Liver abnormalities in pregnancy.

    PubMed

    Than, Nwe Ni; Neuberger, James

    2013-08-01

    Abnormalities of liver function (notably rise in alkaline phosphatase and fall in serum albumin) are common in normal pregnancy, whereas rise in serum bilirubin and aminotransferase suggest either exacerbation of underlying pre-existing liver disease, liver disease related to pregnancy or liver disease unrelated to pregnancy. Pregnant women appear to have a worse outcome when infected with Hepatitis E virus. Liver diseases associated with pregnancy include abnormalities associated hyperemesis gravidarum, acute fatty liver disease, pre-eclampsia, cholestasis of pregnancy and HELLP syndrome. Prompt investigation and diagnosis is important in ensuring a successful maternal and foetal outcome. In general, prompt delivery is the treatment of choice for acute fatty liver, pre-eclampsia and HELLP syndrome and ursodeoxycholic acid is used for cholestasis of pregnancy although it is not licenced for this indication.

  19. Morphological abnormalities in elasmobranchs.

    PubMed

    Moore, A B M

    2015-08-01

    A total of 10 abnormal free-swimming (i.e., post-birth) elasmobranchs are reported from The (Persian-Arabian) Gulf, encompassing five species and including deformed heads, snouts, caudal fins and claspers. The complete absence of pelvic fins in a milk shark Rhizoprionodon acutus may be the first record in any elasmobranch. Possible causes, including the extreme environmental conditions and the high level of anthropogenic pollution particular to The Gulf, are briefly discussed.

  20. Analysis of tracer and thermal transients during reinjection

    SciTech Connect

    Kocabas, I.

    1989-10-01

    This work studied tracer and thermal transients during reinjection in geothermal reserviors and developed a new technique which combines the results from interwell tracer tests and thermal injection-backflow tests to estimate the thermal breakthrough times. Tracer tests are essential to determine the degree of connectivity between the injection wells and the producing wells. To analyze the tracer return profiles quantitatively, we employed three mathematical models namely, the convection-dispersion (CD) model, matrix diffusion (MD) model, and the Avodnin (AD) model, which were developed to study tracer and heat transport in a single vertical fracture. We considered three types of tracer tests namely, interwell tracer tests without recirculation, interwell tracer tests with recirculation, and injection-backflow tracer tests. To estimate the model parameters, we used a nonlinear regression program to match tracer return profiles to the solutions.

  1. Transient tracer applications in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Stöven, T.; Tanhua, T.; Hoppema, M.

    2014-10-01

    Transient tracers can be used to constrain the Inverse-Gaussian transit time distribution (IG-TTD) and thus provide information about ocean ventilation. Individual transient tracers have different time and application ranges which are defined by their atmospheric history (chronological transient tracers) or their decay rate (radioactive transient tracers). The classification ranges from tracers for highly ventilated water masses, e.g. sulfur hexafluoride (SF6), the decay of Tritium (δ3H) and to some extent also dichlorodifluoromethane (CFC-12) to tracers for less ventilated deep ocean basins, e.g. CFC-12, Argon-39 (39Ar) and radiocarbon (14C). The IG-TTD can be empirically constrained by using transient tracer couples with sufficiently different input functions. Each tracer couple has specific characteristics which influence the application limit of the IG-TTD. Here we provide an overview of commonly used transient tracer couples and their validity areas within the IG-TTD by using the concept of tracer age differences (TAD). New measured CFC-12 and SF6 data from a section along 10° E in the Southern Ocean in 2012 are presented. These are combined with a similar data set of 1998 along 6° E in the Southern Ocean as well as with 39Ar data from the early 1980s in the western Atlantic Ocean and the Weddell Sea for investigating the application limit of the IG-TTD and to analyze changes in ventilation in the Southern Ocean. We found that the IG-TTD can be constrained south to 46° S which corresponds to the Subantarctic Front (SAF) denoting the application limit. The constrained IG-TTD north of the SAF shows a slight increase in mean ages between 1998 and 2012 in the upper 1200 m between 42-46° S. The absence of SF6 inhibits ventilation analyses below this depth. The time lag analysis between the 1998 and 2012 data shows an increase in ventilation down to 1000 m and a steady ventilation between 2000 m-bottom south of the SAF between 51-55° S.

  2. Stomata-controlled nighttime COS fluxes in a boreal forest: implications for the use of COS as a GPP tracer

    NASA Astrophysics Data System (ADS)

    Kooijmans, Linda M. J.; Maseyk, Kadmiel; Seibt, Ulli; Vesala, Timo; Mammarella, Ivan; Baker, Ian T.; Franchin, Alessandro; Kolari, Pasi; Sun, Wu; Keskinen, Helmi; Levula, Janne; Chen, Huilin

    2016-04-01

    Carbonyl Sulfide (COS) is a promising new tracer that can be used to partition the Net Ecosystem Exchange into gross primary production (GPP) and respiration. COS and CO2 vegetation fluxes are closely related as these gases share the same diffusion pathway into stomata. This close coupling is the fundamental principle for the use of COS as tracer for GPP. Nonetheless, in contrast to CO2 , the uptake of COS by vegetation is not light-dependent, and therefore the vegetative uptake of COS can continue during the night as long as stomata are open. Nighttime stomatal conductance is observed in a variety of studies, and also nighttime depletion of COS concentrations is reported several times but it is not confirmed with field measurements that the depletion of COS in the night is indeed driven by stomatal opening. In the summer of 2015 a campaign took place at the SMEAR II site in Hyytiälä, Finland to provide better constrained COS flux data for boreal forests using a combination of COS measurements, i.e. atmospheric profile concentrations up to 125 m, eddy-covariance fluxes and soil chamber fluxes, and collocated measurements of stomatal conductance and 222Radon. A high correlation between concentrations of 222Radon and COS implies that the radon-tracer method is a valuable tool to derive nighttime ecosystem COS fluxes. We find that soils contribute to 17% of the total ecosystem COS flux during nighttime in the peak growing season. Nighttime ecosystem COS fluxes show a correlation with stomatal conductance (R2 = 0.3), indicating that nighttime COS fluxes are primarily driven by vegetation. The COS vegetation fluxes will be compared with calculated fluxes from the Simple Biosphere model. Furthermore, the nighttime vegetative COS uptake covers a substantial fraction (25%) of the daily maximum COS uptake by vegetation. Accurate quantification of nighttime COS uptake is required to be able to use COS as a useful tracer for GPP.

  3. Anatomical Abnormalities in Autism?

    PubMed

    Haar, Shlomi; Berman, Sigal; Behrmann, Marlene; Dinstein, Ilan

    2016-04-01

    Substantial controversy exists regarding the presence and significance of anatomical abnormalities in autism spectrum disorders (ASD). The release of the Autism Brain Imaging Data Exchange (∼1000 participants, age 6-65 years) offers an unprecedented opportunity to conduct large-scale comparisons of anatomical MRI scans across groups and to resolve many of the outstanding questions. Comprehensive univariate analyses using volumetric, thickness, and surface area measures of over 180 anatomically defined brain areas, revealed significantly larger ventricular volumes, smaller corpus callosum volume (central segment only), and several cortical areas with increased thickness in the ASD group. Previously reported anatomical abnormalities in ASD including larger intracranial volumes, smaller cerebellar volumes, and larger amygdala volumes were not substantiated by the current study. In addition, multivariate classification analyses yielded modest decoding accuracies of individuals' group identity (<60%), suggesting that the examined anatomical measures are of limited diagnostic utility for ASD. While anatomical abnormalities may be present in distinct subgroups of ASD individuals, the current findings show that many previously reported anatomical measures are likely to be of low clinical and scientific significance for understanding ASD neuropathology as a whole in individuals 6-35 years old.

  4. Journal: A Review of Some Tracer-Test Design Equations for Tracer-Mass Estimation and Sample Collection Frequency

    EPA Science Inventory

    Determination of necessary tracer mass, initial sample-collection time, and subsequent sample-collection frequency are the three most difficult aspects to estimate for a proposed tracer test prior to conducting the tracer test. To facilitate tracer-mass estimation, 33 mass-estima...

  5. Abnormal pressures as hydrodynamic phenomena

    USGS Publications Warehouse

    Neuzil, C.E.

    1995-01-01

    So-called abnormal pressures, subsurface fluid pressures significantly higher or lower than hydrostatic, have excited speculation about their origin since subsurface exploration first encountered them. Two distinct conceptual models for abnormal pressures have gained currency among earth scientists. The static model sees abnormal pressures generally as relict features preserved by a virtual absence of fluid flow over geologic time. The hydrodynamic model instead envisions abnormal pressures as phenomena in which flow usually plays an important role. This paper develops the theoretical framework for abnormal pressures as hydrodynamic phenomena, shows that it explains the manifold occurrences of abnormal pressures, and examines the implications of this approach. -from Author

  6. Tracer-based prediction of thermal reservoir lifetime: scope, limitations, and the role of thermosensitive tracers

    NASA Astrophysics Data System (ADS)

    Ghergut, I.; Behrens, H.; Karmakar, S.; Licha, T.; Nottebohm, M.; Sauter, M.

    2012-04-01

    Thermal-lifetime prediction is a traditional endeavour of inter-well tracer tests conducted in geothermal reservoirs. Early tracer test signals (detectable within the first few years of operation) are expected to correlate with late-time production temperature evolutions ('thermal breakthrough', supposed to not occur before some decades of operation) of a geothermal reservoir. Whenever a geothermal reservoir can be described as a single-fracture system, its thermal lifetime will, ideally, be determined by two parameters (say, fracture aperture and porosity), whose inversion from conservative-tracer test signals is straightforward and non-ambiguous (provided that the tracer tests, and their interpretation, are performed in accordance to the rules of the art). However, as soon as only 'few more' fractures are considered, this clear-cut correlation is broken. A given geothermal reservoir can simultaneously feature a single-fracture behaviour, in terms of heat transport, and a multiple-fracture behaviour, in terms of solute tracer transport (or vice-versa), whose effective values of fracture apertures, spacings, and porosities are essentially uncorrelated between heat and solute tracers. Solute transport parameters derived from conservative-tracer tests will no longer characterize the heat transport processes (and thus temperature evolutions) taking place in the same reservoir. Parameters determining its thermal lifetime will remain 'invisible' to conservative tracers in inter-well tests. We demonstrate this issue at the example of a five-fracture system, representing a deep-geothermal reservoir, with well-doublet placement inducing fluid flow 'obliquely' to the fractures. Thermal breakthrough in this system is found to strongly depend on fracture apertures, whereas conservative-solute tracer signals from inter-well tests in the same system do not show a clear-cut correlation with fracture apertures. Only by using thermosensitive substances as tracers, a reliable

  7. [Molecular abnormalities in lymphomas].

    PubMed

    Delsol, G

    2010-11-01

    Numerous molecular abnormalities have been described in lymphomas. They are of diagnostic and prognostic value and are taken into account for the WHO classification of these tumors. They also shed some light on the underlying molecular mechanisms involved in lymphomas. Overall, four types of molecular abnormalities are involved: mutations, translocations, amplifications and deletions of tumor suppressor genes. Several techniques are available to detect these molecular anomalies: conventional cytogenetic analysis, multicolor FISH, CGH array or gene expression profiling using DNA microarrays. In some lymphomas, genetic abnormalities are responsible for the expression of an abnormal protein (e.g. tyrosine-kinase, transcription factor) detectable by immunohistochemistry. In the present review, molecular abnormalities observed in the most frequent B, T or NK cell lymphomas are discussed. In the broad spectrum of diffuse large B-cell lymphomas microarray analysis shows mostly two subgroups of tumors, one with gene expression signature corresponding to germinal center B-cell-like (GCB: CD10+, BCL6 [B-Cell Lymphoma 6]+, centerine+, MUM1-) and a subgroup expressing an activated B-cell-like signature (ABC: CD10-, BCL6-, centerine-, MUM1+). Among other B-cell lymphomas with well characterized molecular abnormalies are follicular lymphoma (BCL2 deregulation), MALT lymphoma (Mucosa Associated Lymphoid Tissue) [API2-MALT1 (mucosa-associated-lymphoid-tissue-lymphoma-translocation-gene1) fusion protein or deregulation BCL10, MALT1, FOXP1. MALT1 transcription factors], mantle cell lymphoma (cycline D1 [CCND1] overexpression) and Burkitt lymphoma (c-Myc expression). Except for ALK (anaplastic lymphoma kinase)-positive anaplastic large cell lymphoma, well characterized molecular anomalies are rare in lymphomas developed from T or NK cells. Peripheral T cell lymphomas not otherwise specified are a heterogeneous group of tumors with frequent but not recurrent molecular abnormalities

  8. Long residence times - bad tracer tests?

    NASA Astrophysics Data System (ADS)

    Ghergut, Julia; Behrens, Horst; Sauter, Martin

    2015-04-01

    Tracer tests conducted at geothermal well doublets or triplets in the Upper Rhine Rift Valley [1] all face, with very few exceptions so far, one common issue: lack of conclusive tracer test results, or tracer signals still undetectable for longer than one or two years after tracer injection. While the reasons for this surely differ from site to site (Riehen, Landau, Insheim, Bruchsal, ...), its effects on how the usefulness of tracer tests is perceived by the non-tracer community are pretty much the same. The 'poor-signal' frustration keeps nourishing two major 'alternative' endeavours : (I) design and execute tracer tests in single-well injection-withdrawal (push-pull), 'instead of' inter-well flow-path tracing configurations; (II) use 'novel' tracer substances instead of the 'old' ones which have 'obviously failed'. Frustration experienced with most inter-well tracer tests in the Upper Rhine Rift Valley has also made them be regarded as 'maybe useful for EGS' ('enhanced', or 'engineered' geothermal systems, whose fluid RTD typically include a major share of values below one year), but 'no longer worthwhile a follow-up sampling' in natural, large-scale hydrothermal reservoirs. We illustrate some of these arguments with the ongoing Bruchsal case [2]. The inter-well tracer test conducted at Bruchsal was (and still is!) aimed at assessing inter-well connectivity, fluid residence times, and characterizing the reservoir structure [3]. Fluid samples taken at the geothermal production well after reaching a fluid turnover of about 700,000 m3 showed tracer concentrations in the range of 10-8 Minj per m3, in the liquid phase of each sample (Minj being the total quantity of tracer injected as a short pulse at the geothermal re-injection well). Tracer signals might actually be higher, owing to tracer amounts co-precipitated and/or adsorbed onto the solid phase whose accumulation in the samples was unavoidable (due to pressure relief and degassing during the very sampling

  9. Boussinesq modeling of HB06 tracer releases Part 2: Tracer plumes

    NASA Astrophysics Data System (ADS)

    Clark, D. B.; Feddersen, F.; Guza, R. T.

    2010-12-01

    Tracer plumes simulated with a Boussinesq surfzone model (funwaveC) are compared with 5 plumes observed during the HB06 experiment (Huntington Beach, Fall 2006). Surfzone tracer plumes were formed by continuously releasing dye tracer into the wave-driven alongshore current. Bulk cross-shore eddy diffusivities, O(1 m2 s-1), were estimated from the observed plumes and agreed best with a mixing-length scaling based on large 2D eddies [Clark et al., JGR, in press 2010]. The mechanisms for surfzone cross-shore tracer dispersion are not well known, and are explored here with the time-dependent, wave and horizontal eddy resolving, funwaveC model. The funwaveC model is run with observed bathymetry, and initialized in 4m depth with the observed obliquely incident and directionally spread waves. Modeled and observed waves and currents are similar, and discussed in Part 1. Model tracer is dispersed by the surfzone horizontal eddy field, a breaking wave eddy diffusivity, and a small O(0.01 m2 s-1) background diffusivity. Modeled and observed mean plume structures agree, but can be degraded by a mismatch between observed and modeled alongshore currents, especially near the tracer source. Bulk tracer eddy diffusivities agree with HB06 observations, and the long narrow plume assumption (used for diffusion analysis) is discussed with modeled tracer fluxes. The model suggests that cross-shore mixing at time scales of many wave periods is dominated by horizontal eddies, not by the breaking eddy diffusivity.

  10. Feeling Abnormal: Simulation of Deviancy in Abnormal and Exceptionality Courses.

    ERIC Educational Resources Information Center

    Fernald, Charles D.

    1980-01-01

    Describes activity in which student in abnormal psychology and psychology of exceptional children classes personally experience being judged abnormal. The experience allows the students to remember relevant research, become sensitized to the feelings of individuals classified as deviant, and use caution in classifying individuals as abnormal.…

  11. Testing and comparison of four ionic tracers to measure stream flow loss by multiple tracer injection

    USGS Publications Warehouse

    Zellweger, G.W.

    1994-01-01

    An injectate containing lithium, sodium, chloride and bromide was added continuously at five sites along a 507 m study reach of St Kevin Gulch, Lake County, Colorado to determine which sections of the stream were losing water to the stream bed and to ascertain how well the four tracers performed. The acidity of the stream (pH 3.6) made it possible for lithium and sodium, which are normally absorbed by ion exchange with stream bed sediment, to be used as conservative tracers. Net flow losses as low as 0.81 s-1, or 8% of flow, were calculated between measuring sites. By comparing the results of simultaneous injection it was determined whether subsections of the study reach were influent or effluent. Evaluation of tracer concentrations along 116 m of stream indicated that all four tracers behaved conservatively. Discharges measured by Parshall flumes were 4-18% greater than discharges measured by tracer dilution. -from Author

  12. Exploring Hydrofluorocarbons as Groundwater Age Tracers (Invited)

    NASA Astrophysics Data System (ADS)

    Haase, K. B.; Busenberg, E.; Plummer, L. N.; Casile, G.; Sanford, W. E.

    2013-12-01

    Groundwater dating tracers are an essential tool for analyzing hydrologic conditions in groundwater systems. Commonly used tracers for dating post-1940's groundwater include sulfur hexafluoride (SF6), chlorofluorocarbons (CFCs), 3H-3He, and other isotopic tracers (85Kr, δ2H and δ18O isotopes, etc.). Each tracer carries a corresponding set of advantages and limitations imposed by field, analytical, and interpretive methods. Increasing the number available tracers is appealing, particularly if they possess inert chemical properties and unique temporal emission histories from other tracers. Atmospherically derived halogenated trace gases continue to hold untapped potential for new tracers, as they are generally inert and their emission histories are well documented. SF5CF3, and CFC-13 were previously shown to have application as dating tracers, though their low mixing ratios and low solubility require large amounts of water to be degassed for their quantification. Two related groups of compounds, hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are hypothesized to be potential age tracers, having similar mixing ratios to the CFCs and relatively high solubility. However, these compounds yield gas chromatography electron capture detector (GC-ECD) responses that are 10-2 -10-5 less than CFC-12, making purge and trap or field stripping GC-ECD approaches impractical. Therefore, in order to use dissolved HCFCs and HFCs as age tracers, different approaches are needed. To solve this problem, we developed an analytical method that uses an atomic emission detector (GC-AED) in place of an ECD to detect fluorinated compounds. In contrast to the ECD, the AED is a universally sensitive, highly linear, elementally specific detector. The new GC-AED system is being used to measure chlorodifluoromethane (HCFC-22), 1,1,1,2-tetrafluoroethane (HFC-134a), and other fluorinated compounds in one liter water samples to study their potential as age dating tracers. HCFC-22 is a

  13. TRACER - TRACING AND CONTROL OF ENGINEERING REQUIREMENTS

    NASA Technical Reports Server (NTRS)

    Turner, P. R.

    1994-01-01

    TRACER (Tracing and Control of Engineering Requirements) is a database/word processing system created to document and maintain the order of both requirements and descriptive material associated with an engineering project. A set of hierarchical documents are normally generated for a project whereby the requirements of the higher level documents levy requirements on the same level or lower level documents. Traditionally, the requirements are handled almost entirely by manual paper methods. The problem with a typical paper system, however, is that requirements written and changed continuously in different areas lead to misunderstandings and noncompliance. The purpose of TRACER is to automate the capture, tracing, reviewing, and managing of requirements for an engineering project. The engineering project still requires communications, negotiations, interactions, and iterations among people and organizations, but TRACER promotes succinct and precise identification and treatment of real requirements separate from the descriptive prose in a document. TRACER permits the documentation of an engineering project's requirements and progress in a logical, controllable, traceable manner. TRACER's attributes include the presentation of current requirements and status from any linked computer terminal and the ability to differentiate headers and descriptive material from the requirements. Related requirements can be linked and traced. The program also enables portions of documents to be printed, individual approval and release of requirements, and the tracing of requirements down into the equipment specification. Requirement "links" can be made "pending" and invisible to others until the pending link is made "binding". Individuals affected by linked requirements can be notified of significant changes with acknowledgement of the changes required. An unlimited number of documents can be created for a project and an ASCII import feature permits existing documents to be incorporated

  14. Uptake of HNO3 to deliquescent sea-salt particles

    NASA Astrophysics Data System (ADS)

    Guimbaud, C.; Arens, F.; Gutzwiller, L.; Gäggeler, H. W.; Ammann, M.

    2002-06-01

    The uptake of HNO3 to deliquescent airborne sea-salt particles (RH = 55%, P = 760 torr, T = 300 K) at concentrations from 2 to 575 ppbv is measured in an aerosol flow tube using 13N as a tracer. Small particles (~ 70 nm diameter) are used in order to minimize the effect of diffusion in the gas phase on the mass transfer. Below 100 ppbv, an uptake coefficient (gupt) of 0.50 ± 0.20 is derived. At higher concentrations, the uptake coefficient decreases along with the consumption of aerosol chloride. Data interpretation is further supported by using the North American Aerosol Inorganics Model (AIM), which predicts the aqueous phase activities of ions and the gas-phase partial pressures of H2O, HNO3, and HCl at equilibrium for the NaCl/HNO3/H2O system. These simulations show that the low concentration data are obtained far from equilibrium, which implies that the uptake coefficient derived is equal to the mass accommodation coefficient under these conditions. The observed uptake coefficient can serve as input to modeling studies of atmospheric sea-salt aerosol chemistry. The main sea-salt aerosol burden in the marine atmosphere is represented by coarse mode particles (> 1 mm diameter). This implies that diffusion in the gas-phase is the limiting step to HNO3 uptake until the sea-salt has been completely processed.

  15. Thermal Stability of Chelated Indium Activable Tracers

    SciTech Connect

    Chrysikopoulos, Costas; Kruger, Paul

    1986-01-21

    The thermal stability of indium tracer chelated with organic ligands ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) was measured for reservoir temperatures of 150, 200, and 240 C. Measurements of the soluble indium concentration was made as a function of time by neutron activation analysis. From the data, approximate thermal decomposition rates were estimated. At 150 C, both chelated tracers were stable over the experimental period of 20 days. At 200 C, the InEDTA concentration remained constant for 16 days, after which the thermal decomposition occurred at a measured rate constant of k = 0.09 d{sup -1}. The thermal decomposition of InNTA at 200 C showed a first order reaction with a measured rate constant of k = 0.16 d{sup -1}. At 240 C, both indium chelated tracers showed rapid decomposition with rate constants greater than 1.8 d{sup -1}. The data indicate that for geothermal reservoir with temperatures up to about 200 C, indium chelated tracers can be used effectively for transit times of at least 20 days. These experiments were run without reservoir rock media, and do not account for concomitant loss of indium tracer by adsorption processes.

  16. Exercises to Improve Gait Abnormalities

    MedlinePlus

    ... Home About iChip Articles Directories Videos Resources Contact Exercises to Improve Gait Abnormalities Home » Article Categories » Exercise and Fitness Font Size: A A A A Exercises to Improve Gait Abnormalities Next Page The manner ...

  17. Abnormal human sex chromosome constitutions

    SciTech Connect

    1993-12-31

    Chapter 22, discusses abnormal human sex chromosome constitution. Aneuploidy of X chromosomes with a female phenotype, sex chromosome aneuploidy with a male phenotype, and various abnormalities in X chromosome behavior are described. 31 refs., 2 figs.

  18. Thyroid Scan and Uptake

    MedlinePlus

    ... procedures within the last two months that used iodine-based contrast material. Your doctor will instruct you ... a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is also known as a ...

  19. Thyroid Scan and Uptake

    MedlinePlus Videos and Cool Tools

    ... A thyroid scan is a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is ... thyroid function, but does not involve imaging. Nuclear medicine is a branch of medical imaging that uses ...

  20. Ga-67 positivity in sarcoidosis of the skin with coincident thyroid uptake of uncertain etiology

    SciTech Connect

    Moreno, A.J.; Brown, J.M.; Salinas, J.A.; Feaster, B.L.; Brown, T.J.

    1984-03-01

    Gallium-67 citrate scintigraphy of a 26-year-old woman with systemic sarcoidosis demonstrated abnormal radiotracer uptake within multiple biopsy-proven sarcoidal cutaneous lesions and within both lobes of the thyroid gland. The etiology of the thyroidal uptake of the Ga-67 was uncertain but it may represent sarcoidal involvement of the gland.

  1. Triple-phase bone image abnormalities in Lyme arthritis

    SciTech Connect

    Brown, S.J.; Dadparvar, S.; Slizofski, W.J.; Glab, L.B.; Burger, M. )

    1989-10-01

    Arthritis is a frequent manifestation of Lyme disease. Limited triple-phase Tc-99m MDP bone imaging of the wrists and hands with delayed whole-body images was performed in a patient with Lyme arthritis. This demonstrated abnormal joint uptake in the wrists and hands in all three phases, with increased activity seen in other affected joints on delayed whole-body images. These findings are nonspecific and have been previously described in a variety of rheumatologic conditions, but not in Lyme disease. Lyme disease should be considered in the differential diagnosis of articular and periarticular bone scan abnormalities.

  2. Radiobrominated m-tyrosine analog as potential CNS L-dopa PET tracer

    SciTech Connect

    De Jesus, O.T.; Mukherjee, J.

    1988-02-15

    Radiobrominated 6-bromo-m-tyrosine (6-BMT) was prepared and the time course of its localization in selected cerebral and peripheral organs in the mouse was determined. Since m-tyrosine is known to have L-dopa-like properties in vivo, our goal was to assess the utility of a radiolabeled analog as a tracer for cerebral L-dopa. Our preliminary results showed that substantial amounts of 6-BMT is extracted by the mouse brain and that the regional distribution and time course of the radiotracer is consistent with uptake in regions rich in dopamine neurons. Although a more thorough biochemical characterization of 6-BMT is necessary, this or other positron emitting analogs of m-tyrosine, such as an /sup 18/F labelled analog, may be useful PET tracers for the non-invasive study of dopamine turnover in humans.

  3. A Investigation of Partially Extracted Tracers Used to Determine Myocardial Blood Flow with PET.

    NASA Astrophysics Data System (ADS)

    Christian, Bradley Thomas

    Positron Emission Tomography (PET) provides the ability to quantitatively measure mass-specific blood flow to myocardial tissue (ml/min/g tissue). The partially extracted tracers ^{62}Cu -PTSM and two single photon emission computed tomography(SPECT) agents, teboroxime and sestamibi were studied. The latter two demonstrate the effectiveness of PET as a pharmacological tool for SPECT perfusion tracer development. The characteristics of these tracers were compared to commonly used partially extracted tracers ^{13}rm NH_3 and ^{82} Rb. Positron emitting ^{rm 94m}Tc was used to label ligands originally developed for ^{rm 99m} Tc labeling. ^{rm 94m }Tc can be produced by the bombardment of a natural molybdenum foil with an 11Mev proton beam, via the ^{94}rm Mo(p,n)^ {94m}Tc reaction. The production of ^{rm94m}Tc is accompanied by ^{92}Tc, ^ {94}Tc, ^{95} Tc, ^{rm 95m}Tc, ^{96}Tc, and ^{rm 99m}Tc due to the isotopic mixture of natural Mo. The presence of these radionuclidic impurities increase the radiation dose received by the patient and radio chemist. The elimination of these impurities was achieved by irradiating an isotopically enriched target material, ^{94}rm MoO_3. The ability to reclaim the enriched target is essential due to the high cost of the material. Recovery was accomplished by a solvent extraction technique yielding an activity recovery of 80% and target material recovery of 95%. Preliminary data was measured for the myocardial perfusion tracer ^{62}Cu -PTSM. It was found that the uptake of ^ {62}Cu-PTSM is linear for resting flows but a high degree of variability is observed at stress induced flows. This same result was found in the human studies when compared to ^{13} rm NH_3 measured myocardial perfusion values. The dynamic analysis of multiple tracers in the sequence of protocols: (1) acute canine prep ( ^{11}rm CO, ^{82 }Rb, ^{62}Cu-PTSM, ^{13}rm NH_3, ^{94m,99m}Tc-BATO, H_2 ^{14}rm O, ^{18 }FCH_3), (2) chronic canine prep ( ^{82}rm Rb, ^{13 }NH_3

  4. Enhanced Oil Recovery: Aqueous Flow Tracer Measurement

    SciTech Connect

    Joseph Rovani; John Schabron

    2009-02-01

    A low detection limit analytical method was developed to measure a suite of benzoic acid and fluorinated benzoic acid compounds intended for use as tracers for enhanced oil recovery operations. Although the new high performance liquid chromatography separation successfully measured the tracers in an aqueous matrix at low part per billion levels, the low detection limits could not be achieved in oil field water due to interference problems with the hydrocarbon-saturated water using the system's UV detector. Commercial instrument vendors were contacted in an effort to determine if mass spectrometry could be used as an alternate detection technique. The results of their work demonstrate that low part per billion analysis of the tracer compounds in oil field water could be achieved using ultra performance liquid chromatography mass spectrometry.

  5. Asymmetrical F-18 Flurorodeoxyglucose uptake in the breasts: A dilemma solved by patient history.

    PubMed

    Gupta, Ravi Kant; Tripathi, Madhavi; Sahoo, Manas Kumar; Nazar, Aftab Hasan; Agarwal, Krishankant; Kumar, Kunal; Damle, Nishikant; Bal, Chandrasekhar

    2016-01-01

    The present case highlights the importance of history taking in solving the dilemmas of variant F-18 FDG uptake on PET/CT. Asymmetrically increased, abnormal looking, FDG uptake in the right breast of our patient was related to her breast feeding practice. Because of personal preference the patient suckled her child from the right breast only. This resulted in asymmetry of size, increase in glandular breast parenchyma and FDG uptake in the breast that was suckled.

  6. Tracer experiment and model evidence for macrofaunal shaping of microbial nitrogen functions along rocky shores

    NASA Astrophysics Data System (ADS)

    Pfister, Catherine A.; Altabet, Mark A.; Pather, Santhiska; Dwyer, Greg

    2016-06-01

    Seawater microbes as well as those associated with macrobiota are increasingly recognized as a key feature affecting nutrient cycling. Tidepools are ideal natural mesocosms to test macrofauna and microbe interactions, and we quantified rates of microbial nitrogen processing using tracer enrichment of ammonium (15NNH4) or nitrate (15NNO3) when tidepools were isolated from the ocean during low intertidal periods. Experiments were conducted during both day and night as well as in control tidepools and those from which mussels had been removed, allowing us to determine the role of both mussels and daylight in microbial nitrogen processing. We paired time series observations of 15N enrichment in NH4+, NO2- and NO3- with a differential equation model to quantify multiple, simultaneous nitrogen transformations. Mussel presence and daylight increased remineralization and photosynthetic nitrogen uptake. When we compared ammonium gain or loss that was attributed to any tidepool microbes vs. photosynthetic uptake, microbes accounted for 32 % of this ammonium flux on average. Microbial transformations averaged 61 % of total nitrate use; thus, microbial activity was almost 3 times that of photosynthetic nitrate uptake. Because it accounted for processes that diluted our tracer, our differential equation model assigned higher rates of nitrogen processing compared to prior source-product models. Our in situ experiments showed that animals alone elevate microbial nitrogen transformations by 2 orders of magnitude, suggesting that coastal macrobiota are key players in complex microbial nitrogen transformations.

  7. Use of the metabolic tracer carbon-11-acetate for evaluation of regional myocardial perfusion

    SciTech Connect

    Chan, S.Y.; Brunken, R.C.; Phelps, M.E.; Schelbert, H.R. )

    1991-04-01

    The high first-pass myocardial extraction fraction of carbon-11-acetate suggests that its initial uptake depends on blood flow. Accordingly, regional uptake of {sup 11}C-acetate at 4 min was compared to regional perfusion determined with nitrogen-13-ammonia in 119 segments in 15 patients with stable coronary artery disease by two methods. A close correlation was observed between initial relative myocardial concentrations (segmental activity normalized to maximal activity) of both tracers (11C-acetate = 0.88; 13N-ammonia + 0.079; s.e.e. = 0.064, r = 0.94, p less than 0.001). Furthermore, segmental net extractions (E.F), as calculated from the input function and segmental activities, of the two tracers correlated closely by E.FC-11 = 0.55E.FN-13 + 0.080 (s.e.e. = 0.045, r = 0.87, p less than 0.001). These relationships indicate that initial regional myocardial uptake of {sup 11}C-acetate reflects perfusion and that {sup 11}C-acetate permits near simultaneous evaluation of regional oxidative metabolism and of regional myocardial perfusion.

  8. Synthesis of isotopically modified ZnO nanoparticles and their potential as nanotoxicity tracers

    USGS Publications Warehouse

    Dybowska, A.D.; Croteau, M.-N.; Misra, S.K.; Berhanu, D.; Luoma, S.N.; Christian, P.; O'Brien, P.; Valsami-Jones, E.

    2011-01-01

    Understanding the behavior of engineered nanoparticles in the environment and within organisms is perhaps the biggest obstacle to the safe development of nanotechnologies. Reliable tracing is a particular issue for nanoparticles such as ZnO, because Zn is an essential element and a common pollutant thus present at elevated background concentrations. We synthesized isotopically enriched (89.6%) with a rare isotope of Zn (67Zn) ZnO nanoparticles and measured the uptake of 67Zn by L. stagnalis exposed to diatoms amended with the particles. Stable isotope technique is sufficiently sensitive to determine the uptake of Zn at an exposure equivalent to lower concentration range (<15 ??g g-1). Without a tracer, detection of newly accumulated Zn is significant at Zn exposure concentration only above 5000 ??g g-1 which represents some of the most contaminated Zn conditions. Only by using a tracer we can study Zn uptake at a range of environmentally realistic exposure conditions. ?? 2010 Elsevier Ltd. All rights reserved.

  9. Epilepsy and chromosomal abnormalities

    PubMed Central

    2010-01-01

    Background Many chromosomal abnormalities are associated with Central Nervous System (CNS) malformations and other neurological alterations, among which seizures and epilepsy. Some of these show a peculiar epileptic and EEG pattern. We describe some epileptic syndromes frequently reported in chromosomal disorders. Methods Detailed clinical assessment, electrophysiological studies, survey of the literature. Results In some of these congenital syndromes the clinical presentation and EEG anomalies seems to be quite typical, in others the manifestations appear aspecific and no strictly linked with the chromosomal imbalance. The onset of seizures is often during the neonatal period of the infancy. Conclusions A better characterization of the electro clinical patterns associated with specific chromosomal aberrations could give us a valuable key in the identification of epilepsy susceptibility of some chromosomal loci, using the new advances in molecular cytogenetics techniques - such as fluorescent in situ hybridization (FISH), subtelomeric analysis and CGH (comparative genomic hybridization) microarray. However further studies are needed to understand the mechanism of epilepsy associated with chromosomal abnormalities. PMID:20438626

  10. Nitrogen use efficiency evaluation of aerobic rice under field capacity water potential using {sup 15}N isotopic tracer technique

    SciTech Connect

    Wahid, Ahmad Nazrul Abd; Rahim, Sahibin Abd; Rahim, Khairuddin Abdul; Harun, Abdul Rahim

    2015-09-25

    This study was carried out to evaluate the efficiency use of the nitrogen fertilizer on aerobic rice varieties MR219-4 and MR219-9 which were grown aerobically under field capacity water potential at the controlled environment area or shield house. Direct {sup 15}N isotope tracer method was used in this study, whereby the {sup 15}N isotope was utilized as a tracer for nitrogen nutrient uptake. {sup 15}N isotope presence in the samples is determined by using emission spectrometer analysis and percentage of total nitrogen is determined by using Kjeldahl method. {sup 15}N atom access value contained in the sample will be used in determining the effectiveness of the use of nitrogen in fertilizers through the specific calculation formulas. In this work, the data several data of nitrogen derived from fertilizer (Ndff), total nitrogen, nitrogen uptake and nitrogen use efficiency was obtained.

  11. Density tracers give option to float

    SciTech Connect

    Davis, J.J.; Wood, C.J.; Lyman, G.J.

    1986-05-01

    Density tracers, that is, particles of precisely known specific gravities, offer alternative to the float-sink technique for determining separation densities. Usually made of plastic and dosed with heavy metal salts to obtain the desired specific gravity, the tracers are added to the separator feed, collected by hand from the product and reject streams, and sorted into appropriate increments on the basis of color-coding or other markings. After counting, the partition number for each specific gravity is calculated and the circuit partition or tromp curve drawn.

  12. Method of dispersing particulate aerosol tracer

    DOEpatents

    O'Holleran, Thomas P.

    1988-01-01

    A particulate aerosol tracer which comprises a particulate carrier of sheet silicate composition having a particle size up to one micron, and a cationic dopant chemically absorbed in solid solution in the carrier. The carrier is preferably selected from the group consisting of natural mineral clays such as bentonite, and the dopant is selected from the group consisting of rare earth elements and transition elements. The tracers are dispersed by forming an aqueous salt solution with the dopant present as cations, dispersing the carriers in the solution, and then atomizing the solution under heat sufficient to superheat the solution droplets at a level sufficient to prevent reagglomeration of the carrier particles.

  13. Radiopharmaceutical Tracers for Neural Progenitor Cells

    SciTech Connect

    Mangner, Thomas J.

    2006-09-29

    The Technical Report summarizes the results of the synthesis and microPET animal scanning of several compounds labeled with positron-emitting isotopes in normal, neonatal and kainic acid treated (seizure induced) rats as potential PET tracers to image the process of neurogenesis using positron emission tomography (PET). The tracers tested were 3'-deoxy-3'-[F-18]fluorothymidine ([F-18]FLT) and 5'-benzoyl-FTL, 1-(2'-deoxy-2'-[F-18]fluoro-B-D-arabinofuranosyl)-5-bromouracil (FBAU) and 3',5'-dibenzoyl-FBAU, N-[F-18]fluoroacetyl-D-glucosamine (FLAG) and tetraacetyl-FLAG, and L-[1-C-11]leucine.

  14. A review of methods for modelling environmental tracers in groundwater: Advantages of tracer concentration simulation

    NASA Astrophysics Data System (ADS)

    Turnadge, Chris; Smerdon, Brian D.

    2014-11-01

    Mathematical models of varying complexity have been developed since the 1960s to interpret environmental tracer concentrations in groundwater flow systems. This review examines published studies of model-based environmental tracer interpretation, the progress of different modelling approaches, and also considers the value of modelling tracer concentrations directly rather than estimations of groundwater age. Based on citation metrics generated using the Web of Science and Google Scholar reference databases, the most highly utilised interpretation approaches are lumped parameter models (421 citations), followed closely by direct age models (220 citations). A third approach is the use of mixing cell models (99 citations). Although lumped parameter models are conceptually simple and require limited data, they are unsuitable for characterising the internal dynamics of a hydrogeological system and/or under conditions where large scale anthropogenic stresses occur within a groundwater basin. Groundwater age modelling, and in particular, the simulation of environmental tracer transport that explicitly accounts for the accumulation and decay of tracer mass, has proven to be highly beneficial in constraining numerical models. Recent improvements in computing power have made numerical simulation of tracer transport feasible. We argue that, unlike directly simulated ages, the results of tracer mass transport simulation can be compared directly to observations, without needing to correct for apparent age bias or other confounding factors.

  15. Magnetic resonance imaging of slow water flow during infiltration and evaporation by tracer motion

    NASA Astrophysics Data System (ADS)

    Pohlmeier, A.; Haber-Pohlmeier, S.; Bechtold, M.; Vanderborght, J.; Vereecken, H.

    2012-04-01

    Water fluxes in soils control many processes in the environment like plant nutrition, solute and pollutant transport. In the last two decades non-invasive visualization methods have been adapted to monitor flux processes on the small scale. Magnetic resonance imaging (MRI), also well known from medical diagnostics, is one of the most versatile ones. It mostly probes directly the substance of interest: water, and it offers many opportunities to manipulate the observed signals for creating different contrasts and thus probing different properties of the porous medium and the embedded fluids. For example, one can make the signal sensitive to the total proton density, i. e. water content, to spatial distributions of relaxation times which reflect pore sizes, to spatial distributions of transport coefficients, and to concentration of contrast agents by using strongly T1 weighted MRI pulse sequences. In this presentation we use GdDTPA2- for monitoring flux processes in soil columns in an ultra-wide bore MRI scanner. It offers the opportunity for monitoring slow water fluxes mainly occurring in soil systems which are not monitorable with direct MRI flow imaging. This contrast agent is most convenient since it behaves conservatively, i.e. it does not sorb at different soil materials and it is chemically stable. Firstly, we show that its mode of action in natural porous media is identical to that known from medical applications as proved by the identical relaxivity parameters [1]. Secondly, the tracer is applied for the visualization of flux processes during evaporation-driven flow. Theoretical considerations by forward simulation predicted a lateral redistribution of solutes during evaporative upward fluxes from highly conductive fine material to neighbouring domains with low water content and conductivity. Here we could prove that such near-surface redistribution really takes place [2]. Thirdly, this tracer is applied for the investigation of water uptake by root systems

  16. Soil processes drive seasonal variation in retention of 15N tracers in a deciduous forest catchment.

    PubMed

    Goodale, Christine L; Fredriksen, Guinevere; Weiss, Marissa S; McCalley, K; Sparks, Jed P; Thomas, Steven A

    2015-10-01

    Seasonal patterns of stream nitrate concentration have long been interpreted as demonstrating the central role of plant uptake in regulating stream nitrogen loss from forested catchments. Soil processes are rarely considered as important drivers of these patterns. We examined seasonal variation in N retention in a deciduous forest using three whole-ecosystem 15N tracer additions: in late April (post-snowmelt, pre-leaf-out), late July (mid-growing- season), and late October (end of leaf-fall). We expected that plant 15N uptake would peak in late spring and midsummer, that immobilization in surface litter and soil would peak the following autumn leaf-fall, and that leaching losses would vary inversely with 15N retention. Similar to most other 15N tracer studies, we found that litter and soils dominated ecosystem retention of added 15N. However, 15N recovery in detrital pools varied tremendously by season, with > 90% retention in spring and autumn and sharply reduced 15N retention in late summer. During spring, over half of the 15N retained in soil occurred within one day in the heavy (mineral-associated) soil fraction. During summer, a large decrease in 15N retention one week after addition coincided with increased losses of 15NO3- to soil leachate and seasonal increases in soil and stream NO3- concentrations, although leaching accounted for only a small fraction of the lost 15N (< 0.2%). Uptake of 15N into roots did not vary by season and accounted for < 4% of each tracer addition. Denitrification or other processes that lead to N gas loss may have consumed the rest. These measurements of 15N movement provide strong evidence for the dominant role of soil processes in regulating seasonal N retention and losses in this catchment and perhaps others with similar soils.

  17. Preclinical evaluation of RYM1, a novel MMP-targeted tracer for imaging aneurysm.

    PubMed

    Toczek, Jakub; Ye, Yunpeng; Gona, Kiran; Kim, Hye-Yeong; Han, Jinah; Razavian, Mahmoud; Golestani, Reza; Zhang, Jiasheng; Wu, Terence; Jung, Jae-Joon; Sadeghi, Mehran

    2017-03-30

    (99m)Tc-RYM1 microSPECT/CT images showed higher uptake of the tracer in AAA compared to non-dilated aortae. Finally, aortic uptake of (99m)Tc-RYM1 in vivo correlated with aortic MMP activity and CD68 expression. Conclusion: The newly developed pan-MMP inhibitor-based tracer, (99m)Tc-RYM1 displays favorable pharmacokinetics for early vascular imaging, and enables specific detection of inflammation and MMP activity in aneurysm.

  18. Skeletal abnormalities in homocystinuria.

    PubMed Central

    Brenton, D. P.

    1977-01-01

    The skeletal changes of thirty-four patients with the biochemical and clinical features of cystathionine synthase deficiency are described. It is emphasized that there is clinical evidence of excessive bone growth and the formation for bone which is structurally weaker than normal. The similarities and differences between this condition and Marfan's syndrome are stressed and the possible nature of the connective tissue defect leading to the skeletal changes discussed. The most characteristic skeletal changes in homocystinuria are the skeletal disproportion (pubis-heel length greater than crown-pubis length), the abnormal vertebrae, sternal deformities, genu valgum and large metaphyses and epiphyses. Images Fig. 2 Fig. 3 Fig. 4 Fig. 8 Fig. 9 Fig. 10 PMID:917963

  19. Eye movement abnormalities.

    PubMed

    Moncayo, Jorge; Bogousslavsky, Julien

    2012-01-01

    Generation and control of eye movements requires the participation of the cortex, basal ganglia, cerebellum and brainstem. The signals of this complex neural network finally converge on the ocular motoneurons of the brainstem. Infarct or hemorrhage at any level of the oculomotor system (though more frequent in the brain-stem) may give rise to a broad spectrum of eye movement abnormalities (EMAs). Consequently, neurologists and particularly stroke neurologists are routinely confronted with EMAs, some of which may be overlooked in the acute stroke setting and others that, when recognized, may have a high localizing value. The most complex EMAs are due to midbrain stroke. Horizontal gaze disorders, some of them manifesting unusual patterns, may occur in pontine stroke. Distinct varieties of nystagmus occur in cerebellar and medullary stroke. This review summarizes the most representative EMAs from the supratentorial level to the brainstem.

  20. Na sup + uptake into colonic enterocyte membrane vesicles

    SciTech Connect

    Bridges, R.J.; Garty, H.; Benos, D.J.; Rummel, W. Weizmann Institute of Science, Rehovot Univ. of Alabama, Birmingham )

    1988-04-01

    Na{sup +} uptake was studied in colonic enterocyte membrane vesicles prepared from normal and dexamethasone-treated rats. Vesicles from rats treated with dexamethasone demonstrated a fivefold greater {sup 22}Na{sup +} uptake compared with vesicles from normal rats. Most of the tracer uptake in membranes derived from treated rats occurred through a conductive, amiloride-blockable pathway located in vesicles with low native K{sup +} permeability and high Cl{sup {minus}} permeability. Kinetic analysis of the amiloride inhibition curve revealed the presence of two amiloride-blockable pathways, one with a high affinity accounting for 85% of the uptake, and one with a low affinity accounting for only 12% of the uptake. Only the low-affinity pathway was detected with vesicles from normal rats. The high sensitivity to amiloride, the dependence on dexamethasone pretreatment, and the relative permeabilities to K{sup +} and Cl{sup {minus}} indicate that most of the {sup 22}Na{sup +} uptake in membranes derived from treated rats is through a Na{sup +}-specific channel located in apical membrane vesicles. Preincubation of the isolated cells from dexamethasone-treated rats at 37{degree}C in Ca{sup 2+}-free solutions before homogenization and membrane vesicle purification caused a 5- to 10-fold increase in amiloride-blockable {sup 22}Na{sup +} uptake compared with vesicles derived from cells maintained at 0{degree}C. The addition of Ca{sup 2+}, but not of Mg{sup 2+}, to the incubation solution markedly reduced this temperature-dependent enhancement in {sup 22}Na{sup +} uptake. These results suggest that Na{sup +} transport in colonic enterocytes from dexamethasone-treated rats is regulated by a Ca{sup 2+}-dependent, temperature-sensitive process which causes a sustained change in the apical membrane.

  1. Autoradiography screening of potential positron emission tomography tracers for asymptomatic abdominal aortic aneurysms

    PubMed Central

    Estrada, Sergio; Hall, Håkan; Wanhainen, Anders; Björck, Martin; Sörensen, Jens; Antoni, Gunnar

    2014-01-01

    Objective The aetiology and early pathophysiological mechanisms of aortic aneurysm formation are still unknown and challenging to study in vivo. Positron emission tomography (PET) is a potentially valuable instrument for non-invasive in vivo pathophysiological studies. No specific tracer to identify the pathophysiological process of aneurysmal dilatation is yet available, however. The aim of this study was to explore if different PET tracers could be useful to image aneurysmal disease. Methods and results Human aneurysmal aortic tissue, collected during elective resection of abdominal aortic aneurysm (AAA) of asymptomatic patients, was investigated in vitro by means of autoradiography with [68Ga]CRP-binder targeting C-reactive protein, [11C]DAA1106 targeting translocator protein (18 kDa), [11C]D-deprenyl with unknown target receptor, [11C]deuterium-L-deprenyl targeting astrocytes, [18F]fluciclatide targeting integrin αVβ3, [68Ga]IMP461 and bi-specific antibody TF2 052107 targeting carcinoembryonic antigen, [18F]F-metomidate targeting mitochondrial cytochrome P-450 species in the adrenal cortex, and [18F]vorozole targeting aromatase. Of the investigated tracers, only [18F]fluciclatide exhibited specific binding, whereas the other PET tracers failed to show specific uptake in the investigated tissue and are probably not useful for the intended purpose. Conclusion It seems likely that αVβ3 integrin expression in AAA can be visualized with PET and that the αVβ3 selective tracer, [18F]fluciclatide, may be suitable for in vivo molecular imaging of asymptomatic AAA. Additional evaluation of [18F]fluciclatide and αVβ3 integrin expression in AAA will be performed in vitro as well as in vivo. PMID:24555564

  2. A field measurement perspective on the current and future use of carbonyl sulphide as a carbon cycle tracer

    NASA Astrophysics Data System (ADS)

    Maseyk, Kadmiel; Sun, Wu; Lett, Celine; Juarez, Sabrina; Seibt, Ulli

    2015-04-01

    Carbonyl sulphide (COS) is gaining increasing traction as a tracer to constrain gross terrestrial biosphere-atmosphere CO2 fluxes, due to the close coupling between photosynthesis and COS uptake by plants. Results from laboratory, field and atmospheric measurements, combined with modeling analyses, have all confirmed the potential of COS, but as with any new approach, many details still remain to be resolved. Drawing on results from our field campaigns that include component (branch and soil) and ecosystem COS flux measurements in a range of environments, I will provide a view on what we have learned about using COS as a carbon cycle tracer. These measurements support the view that ecosystem COS fluxes are typically dominated by canopy uptake, and have provided insight into carbon cycle processes not available from CO2 measurements alone. They have also provided some interesting surprises that suggest COS data may also provide information on other biogeochemical and plant processes such as phenology. Our results support the addition of COS to our measurement arsenal to improve our understanding and monitoring of the terrestrial biosphere, but moving forward will require addressing some key uncertainties. These include the role of the soil and the variation in the leaf-level COS to CO2 uptake ratio in different environments. Combining COS with stable isotope tracers, particularly CO2, can provide a powerful way with which to both improve our understanding of COS biogeochemistry and constrain our estimates of terrestrial CO2 fluxes.

  3. Using Neural Networks to Describe Tracer Correlations

    NASA Technical Reports Server (NTRS)

    Lary, D. J.; Mueller, M. D.; Mussa, H. Y.

    2003-01-01

    Neural networks are ideally suited to describe the spatial and temporal dependence of tracer-tracer correlations. The neural network performs well even in regions where the correlations are less compact and normally a family of correlation curves would be required. For example, the CH4-N2O correlation can be well described using a neural network trained with the latitude, pressure, time of year, and CH4 volume mixing ratio (v.m.r.). In this study a neural network using Quickprop learning and one hidden layer with eight nodes was able to reproduce the CH4-N2O correlation with a correlation co- efficient of 0.9995. Such an accurate representation of tracer-tracer correlations allows more use to be made of long-term datasets to constrain chemical models. Such as the dataset from the Halogen Occultation Experiment (HALOE) which has continuously observed CH4, (but not N2O) from 1991 till the present. The neural network Fortran code used is available for download.

  4. Travel-time-based thermal tracer tomography

    NASA Astrophysics Data System (ADS)

    Somogyvári, Márk; Bayer, Peter; Brauchler, Ralf

    2016-05-01

    Active thermal tracer testing is a technique to get information about the flow and transport properties of an aquifer. In this paper we propose an innovative methodology using active thermal tracers in a tomographic setup to reconstruct cross-well hydraulic conductivity profiles. This is facilitated by assuming that the propagation of the injected thermal tracer is mainly controlled by advection. To reduce the effects of density and viscosity changes and thermal diffusion, early-time diagnostics are used and specific travel times of the tracer breakthrough curves are extracted. These travel times are inverted with an eikonal solver using the staggered grid method to reduce constraints from the pre-defined grid geometry and to improve the resolution. Finally, non-reliable pixels are removed from the derived hydraulic conductivity tomograms. The method is applied to successfully reconstruct cross-well profiles as well as a 3-D block of a high-resolution fluvio-aeolian aquifer analog data set. Sensitivity analysis reveals a negligible role of the injection temperature, but more attention has to be drawn to other technical parameters such as the injection rate. This is investigated in more detail through model-based testing using diverse hydraulic and thermal conditions in order to delineate the feasible range of applications for the new tomographic approach.

  5. Blood Tracer Kinetics in the Arterial Tree

    PubMed Central

    Kellner, Elias; Gall, Peter; Günther, Matthias; Reisert, Marco; Mader, Irina; Fleysher, Roman; Kiselev, Valerij G.

    2014-01-01

    Evaluation of blood supply of different organs relies on labeling blood with a suitable tracer. The tracer kinetics is linear: Tracer concentration at an observation site is a linear response to an input somewhere upstream the arterial flow. The corresponding impulse response functions are currently treated empirically without incorporating the relation to the vascular morphology of an organ. In this work we address this relation for the first time. We demonstrate that the form of the response function in the entire arterial tree is reduced to that of individual vessel segments under approximation of good blood mixing at vessel bifurcations. The resulting expression simplifies significantly when the geometric scaling of the vascular tree is taken into account. This suggests a new way to access the vascular morphology in vivo using experimentally determined response functions. However, it is an ill-posed inverse problem as demonstrated by an example using measured arterial spin labeling in large brain arteries. We further analyze transport in individual vessel segments and demonstrate that experimentally accessible tracer concentration in vessel segments depends on the measurement principle. Explicit expressions for the response functions are obtained for the major middle part of the arterial tree in which the blood flow in individual vessel segments can be treated as laminar. When applied to the analysis of regional cerebral blood flow measurements for which the necessary arterial input is evaluated in the carotid arteries, present theory predicts about 20% underestimation, which is in agreement with recent experimental data. PMID:25299048

  6. Subsurface barrier integrity verification using perfluorocarbon tracers

    SciTech Connect

    Sullivan, T.M.; Heiser, J.; Milian, L.; Senum, G.

    1996-12-01

    Subsurface barriers are an extremely promising remediation option to many waste management problems. Gas phase tracers include perfluorocarbon tracers (PFT`s) and chlorofluorocarbon tracers (CFC`s). Both have been applied for leak detection in subsurface systems. The focus of this report is to describe the barrier verification tests conducted using PFT`s and analysis of the data from the tests. PFT verification tests have been performed on a simulated waste pit at the Hanford Geotechnical facility and on an actual waste pit at Brookhaven National Laboratory (BNL). The objective of these tests were to demonstrate the proof-of-concept that PFT technology can be used to determine if small breaches form in the barrier and for estimating the effectiveness of the barrier in preventing migration of the gas tracer to the monitoring wells. The subsurface barrier systems created at Hanford and BNL are described. The experimental results and the analysis of the data follow. Based on the findings of this study, conclusions are offered and suggestions for future work are presented.

  7. Nanoparticle tracers in calcium carbonate porous media

    NASA Astrophysics Data System (ADS)

    Li, Yan Vivian; Cathles, Lawrence M.; Archer, Lynden A.

    2014-08-01

    Tracers are perhaps the most direct way of diagnosing subsurface fluid flow pathways for ground water decontamination and for natural gas and oil production. Nanoparticle tracers could be particularly effective because they do not diffuse away from the fractures or channels where flow occurs and thus take much less time to travel between two points. In combination with a chemical tracer they can measure the degree of flow concentration. A prerequisite for tracer applications is that the particles are not retained in the porous media as the result of aggregation or sticking to mineral surfaces. By screening eight nanoparticles (3-100 nm in diameter) for retention when passed through calcium carbonate packed laboratory columns in artificial oil field brine solutions of variable ionic strength we show that the nanoparticles with the least retention are 3 nm in diameter, nearly uncharged, and decorated with highly hydrophilic polymeric ligands. The details of these column experiments and the tri-modal distribution of zeta potential of the calcite sand particles in the brine used in our tests suggests that parts of the calcite surface have positive zeta potential and the retention of negatively charged nanoparticles occurs at these sites. Only neutral nanoparticles are immune to at least some retention.

  8. Hybrid tracers for sentinel node biopsy.

    PubMed

    Van Den Berg, N S; Buckle, T; Kleinjan, G I; Klop, W M; Horenblas, S; Van Der Poel, H G; Valdés-Olmos, R A; Van Leeuwen, F I

    2014-06-01

    Conventional sentinel node (SN) mapping is performed by injection of a radiocolloid followed by lymphoscintigraphy to identify the number and location of the primary tumor draining lymph node(s), the so-called SN(s). Over the last decade research has focused on the introduction of new imaging agents that can further aid (surgical) SN identification. Different tracers for SN mapping, with varying sizes and isotopes have been reported, most of which have proven their value in a clinical setting. A major challenge lies in transferring this diagnostic information obtained at the nuclear medicine department to the operating theatre thereby providing the surgeon with (image) guidance. Conventionally, an intraoperative injection of vital blue dye or a fluorescence dye is given to allow intraoperative optical SN identification. However, for some indications, the radiotracer-based approach remains crucial. More recently, hybrid tracers, that contain both a radioactive and fluorescent label, were introduced to allow for direct integration of pre- and intraoperative guidance technologies. Their potential is especially high when they are used in combination with new surgical imaging modalities and navigation tools. Next to a description of the known tracers for SN mapping, this review discusses the application of hybrid tracers during SN biopsy and how the introduction of these new techniques can further aid in translation of nuclear medicine information into the operating theatre.

  9. Halon-1301, a new Groundwater Age Tracer

    NASA Astrophysics Data System (ADS)

    Beyer, Monique; van der Raaij, Rob; Morgenstern, Uwe; Jackson, Bethanna

    2015-04-01

    Groundwater dating is an important tool to assess groundwater resources in regards to direction and time scale of groundwater flow and recharge and to assess contamination risks and manage remediation. To infer groundwater age information, a combination of different environmental tracers, such as tritium and SF6, are commonly used. However ambiguous age interpretations are often faced, due to a limited set of available tracers and limitations of each tracer method when applied alone. There is a need for additional, complementary groundwater age tracers. We recently discovered that Halon-1301, a water soluble and entirely anthropogenic gaseous substance, may be a promising candidate [Beyer et al, 2014]. Halon-1301 can be determined along with SF6, SF5CF3 and CFC-12 in groundwater using a gas chromatography setup with attached electron capture detector developed by Busenberg and Plummer [2008]. Halon-1301 has not been assessed in groundwater. This study assesses the behaviour of Halon-1301 in water and its suitability as a groundwater age tracer. We determined Halon-1301 in 17 groundwater and various modern (river) waters sites located in 3 different groundwater systems in the Wellington Region, New Zealand. These waters have been previously dated with tritium, CFC-12, CFC-11 and SF6 with mean residence times ranging from 0.5 to over 100 years. The waters range from oxic to anoxic and some show evidence of CFC contamination or degradation. This allows us to assess the different properties affecting the suitability of Halon-1301 as groundwater age tracer, such as its conservativeness in water and local contamination potential. The samples are analysed for Halon-1301 and SF6simultaneously, which allows identification of issues commonly faced when using gaseous tracers such as contamination with modern air during sampling. Overall we found in the assessed groundwater samples Halon-1301 is a feasible new groundwater tracer. No sample indicated significantly elevated

  10. AIR INFILTRATION MEASUREMENTS USING TRACER GASES: A LITERATURE REVIEW

    EPA Science Inventory

    The report gives results of a literature review of air filtration measurements using tracer gases, including sulfur hexafluoride, hydrogen, carbon monoxide, carbon dioxide, nitrous oxide, and radioactive argon and krypton. Sulfur hexafluoride is the commonest tracer gas of choice...

  11. Tracer Interpretation Using Temporal Moments on a Spreadsheet

    SciTech Connect

    G. Michael Shook; J. Hope Forsmann

    2005-06-01

    This report presents a method for interpreting geothermal tracer tests. The method is based on the first temporal moment (mean residence time) of the tracer in the subsurface. The individual steps required to interpret a tracer test are reviewed and discussed. And an example tracer test directs the user through the interpretation method. An Excel spreadsheet application of the interpretation method is a companion document to this report.

  12. Measuring and modeling of a three-dimensional tracer transport in a planted soil column

    NASA Astrophysics Data System (ADS)

    Schroeder, N.; Javaux, M.; Haber-Pohlmeier, S.; Pohlmeier, A. J.; Huber, K.; Vereecken, H.; Vanderborght, J.

    2013-12-01

    Water flow from soil to root is driven by the plant transpiration and an important component of the hydrological cycle. The model R-SWMS combines three-dimensional (3D) water flow and solute transport in soil with a detailed description of root structure in three dimensions [1,2]. This model offers the possibility to calculate root water and solute uptake and flow within the roots, which enables explicit studies with respect to the distribution of water and solutes around the roots as well as local processes at the root-soil interface. In this study, we compared measured data from a tracer experiment using Magnetic Resonance Imaging (MRI) with simulations in order to assess the distribution and magnitude of the water uptake of a young lupine plant. An aqueous solution of the Gadolinium-complex (Gd-DTPA2-) was chosen as a tracer, as it behaves conservatively and is ideally suited for MRI. Water flow in the soil towards the roots can thus be visualized by following the change in tracer concentrations over time. The data were obtained by MRI, providing high resolution 3D images of the tracer distribution and root architecture structures by using a spin echo pulse sequence, which is strongly T1- weighted to be tracer sensitive [3], and T2 -weighted for root imaging [4]. This experimental setup was simulated using the 3D high-resolution numerical model R-SWMS. The comparison between MRI data and the simulations showed extensive effects of root architecture parameters on solute spreading. Although the results of our study showed the strength of combining non-invasive measurements and 3D modeling of solute and water flow in soil-root systems, where the derivation of plant hydraulic parameters such as axial and radial root conductivities is possible, current limitations were found with respect to MRI measurements and process description. [1] Javaux, M., T. Schröder, J. Vanderborght, and H. Vereecken (2008), Use of a Three-Dimensional Detailed Modeling Approach for

  13. Clinical relevance of abnormal scintigraphic findings of adult equine ribs.

    PubMed

    Dahlberg, Jessica A; Ross, Michael W; Martin, Benson B; Davidson, Elizabeth J; Leitch, Midge

    2011-01-01

    Horses with cranial rib abnormalities may exhibit severe acute lameness and may have unusual gait deficits characterized by forelimb abduction during protraction at the walk. Horses with caudal rib abnormalities may resent being saddled and ridden. In a retrospective evaluation of 20 horses with a documented rib lesion, 25 sites of increased radiopharmaceutical uptake were found in one or more ribs. Thirteen (52%) scintigraphic lesions involved the first rib; four were located immediately dorsal to the sternal articulation, eight were near the costochondral junction and one was at the costovertebral junction. Six (24%) scintigraphic rib lesions involved ribs 2-8; one was located immediately dorsal to the sternal articulation, three were at the costovertebral junction and two were near the costochondral junction. Six (24%) scintigraphic rib lesions involved the mid-portion (five) or costovertebral junction (one) of ribs 9-18. The 20 horses were divided into three groups based on the clinical relevance of the scintigraphic findings. Group 1 (n=3) horses had clinical signs attributed to a rib abnormality; Group 2 (n=6) horses had a rib abnormality that was a plausible explanation for clinical signs; Group 3 (n=11) horses had clinical signs that could not be attributed to a rib abnormality. For horses with cranial rib abnormalities, a modified lateral scintigraphic image with the ipsilateral limb pulled caudally and a left (right) 45° caudal-right (left) radiograph facilitated the diagnosis.

  14. Industrial tracer application in People's Republic of China

    SciTech Connect

    Maoyi, S.

    1988-01-01

    A number of important applications of radioisotopes and their compounds used as tracers in petroleum industry, metallurgical industry, mechanical industry, chemical industry, electronic industry, hydrology and water conservancy in China are introduced in this paper. The tracer technique applied to entomology is also mentioned. The industrial tracer applications are successful and beneficial in People's Republic of China from the examples given.

  15. Extraskeletal uptake of technetium-99m-MDP in sites of heparin administration.

    PubMed

    Challa, S; Miller, J H

    1998-05-01

    A 19-yr-old woman with juvenile diabetes and protein C deficiency was referred for a bone scan to rule out osteomyelitis of the right tibia. The bone scan did not reveal evidence of osteomyelitis. There was, however, extraskeletal uptake of the 99mTc bone tracer in the anterior abdominal wall confined to the sites of subcutaneous heparin administration. This case is presented because of its interesting scintigraphic findings and to discuss the association of protein C deficiency and heparin administration as a cause of extraskeletal 99mTc bone tracer accumulation.

  16. Root traits explain observed tundra vegetation nitrogen uptake patterns: Implications for trait-based land models

    NASA Astrophysics Data System (ADS)

    Zhu, Qing; Iversen, Colleen M.; Riley, William J.; Slette, Ingrid J.; Vander Stel, Holly M.

    2016-12-01

    Ongoing climate warming will likely perturb vertical distributions of nitrogen availability in tundra soils through enhancing nitrogen mineralization and releasing previously inaccessible nitrogen from frozen permafrost soil. However, arctic tundra responses to such changes are uncertain, because of a lack of vertically explicit nitrogen tracer experiments and untested hypotheses of root nitrogen uptake under the stress of microbial competition implemented in land models. We conducted a vertically explicit 15N tracer experiment for three dominant tundra species to quantify plant N uptake profiles. Then we applied a nutrient competition model (N-COM), which is being integrated into the ACME Land Model, to explain the observations. Observations using an 15N tracer showed that plant N uptake profiles were not consistently related to root biomass density profiles, which challenges the prevailing hypothesis that root density always exerts first-order control on N uptake. By considering essential root traits (e.g., biomass distribution and nutrient uptake kinetics) with an appropriate plant-microbe nutrient competition framework, our model reasonably reproduced the observed patterns of plant N uptake. In addition, we show that previously applied nutrient competition hypotheses in Earth System Land Models fail to explain the diverse plant N uptake profiles we observed. Our results cast doubt on current climate-scale model predictions of arctic plant responses to elevated nitrogen supply under a changing climate and highlight the importance of considering essential root traits in large-scale land models. Finally, we provided suggestions and a short synthesis of data availability for future trait-based land model development.

  17. The Ecohydrology of Kruger National Park: What 220,000 Tracer Injections Can Tell Us

    NASA Astrophysics Data System (ADS)

    Kulmatiski, A.; Beard, K. H.

    2015-12-01

    For over 100 years root biomass has been used to infer patterns of resource uptake. These patterns are used to understand plant growth, plant coexistence and water cycles. In savannas, observations of root biomass led to the two-layer hypothesis which suggests that grasses outcompete trees due in part to dense shallow root mats that have been presumed to provide grasses with more soil water than trees. Here we show that root biomass can be a poor indicator of resource uptake. More specifically, we combine a hydrologic tracer experiment with a soil water model to measure the amount of water plant species remove from different soil depths. We use this approach in mesic, xeric, sandy and clay sites and reveal surprisingly similar rooting patterns among sites. Our approach revealed that the depth from which grasses and trees absorbed half of their annual water was twice as deep (23 and 43 cm, respectively) and niche partitioning was greater (0.82 vs. 0.95) than would be inferred from root biomass or tracer uptake data alone. Contrary to long-standing assumptions based on root biomass distributions, our approach suggested that shallow rooting patterns provided grasses with 32% less water than slightly deeper tree rooting patterns. Our results provided good predictions (R2 = 0.82) of soil water content throughout the soil profile and throughout the growing season and helped predict tree and grass growth responses to treatments in separate precipitation manipulation experiments. Results provide an example of how quantifying water uptake can reveal patterns of root activity that are not apparent from root biomass distributions and help resolve long-standing questions about species coexistence and water use.

  18. Predictive modeling of transient storage and nutrient uptake: Implications for stream restoration

    USGS Publications Warehouse

    O'Connor, Ben L.; Hondzo, Miki; Harvey, Judson

    2010-01-01

    This study examined two key aspects of reactive transport modeling for stream restoration purposes: the accuracy of the nutrient spiraling and transient storage models for quantifying reach-scale nutrient uptake, and the ability to quantify transport parameters using measurements and scaling techniques in order to improve upon traditional conservative tracer fitting methods. Nitrate (NO3–) uptake rates inferred using the nutrient spiraling model underestimated the total NO3– mass loss by 82%, which was attributed to the exclusion of dispersion and transient storage. The transient storage model was more accurate with respect to the NO3– mass loss (±20%) and also demonstrated that uptake in the main channel was more significant than in storage zones. Conservative tracer fitting was unable to produce transport parameter estimates for a riffle-pool transition of the study reach, while forward modeling of solute transport using measured/scaled transport parameters matched conservative tracer breakthrough curves for all reaches. Additionally, solute exchange between the main channel and embayment surface storage zones was quantified using first-order theory. These results demonstrate that it is vital to account for transient storage in quantifying nutrient uptake, and the continued development of measurement/scaling techniques is needed for reactive transport modeling of streams with complex hydraulic and geomorphic conditions.

  19. Simultaneous measurements of umbilical uptake, fetal utilization rate, and fetal turnover rate of glucose.

    PubMed

    Hay, W W; Sparks, J W; Quissell, B J; Battaglia, F C; Meschia, G

    1981-06-01

    Fetal umbilical glucose uptake was compared with simultaneous measurements of glucose turnover and utilization rates in 12 pregnant sheep, at a mean of 137 days gestational age (range, 118-146 days). Umbilical glucose uptake was calculated by application of the Fick principle. Fetal glucose turnover rate was measured by a primed-constant infusion of [14C]- and [3H]glucose (glucose turnover rate = tracer infusion rate divided by fetal glucose sp act). The calculation of fetal glucose utilization rate required substraction of the loss of tracer to the placenta from the tracer infusion rate, thus defining the net tracer entry into the fetus for direct comparison with the net umbilical glucose uptake. In fed, normoglycemic sheep, these measurements demonstrated statistical equivalence of umbilical glucose uptake rate (4.77 mg.min-1.kg-1 +/- 0.34 SE) and glucose utilization rate ([14C]glucose, 5.58 mg.min-1.kg-1 +/- 0.54 SE; and [3H]glucose, 7.19 mg.min-1.kg-1 +/- 1.24 SE) when tested by two-way analysis of variance (P greater than 0.1). In three fasted, hypoglycemic sheep, the umbilical glucose uptake rate fell to 1.43 mg.min-1.kg-1 +/- 0.56 SE, which was considerably lower than the simultaneous glucose utilization rate ([14C]glucose, 4.78 mg.min-1.kg-1 +/- 0.48 SE; and [3H]glucose, 6.81 mg.min-1.kg-1 +/- 2.19 SE). Thus, in the normoglycemic, late-gestation fetal lamb, there appears to be little glucogenesis, whereas glucogenesis may become significant during fasting-induced fetal hypoglycemia.

  20. Hydrogen peroxide-dependent uptake of iodine by marine Flavobacteriaceae bacterium strain C-21.

    PubMed

    Amachi, Seigo; Kimura, Koh; Muramatsu, Yasuyuki; Shinoyama, Hirofumi; Fujii, Takaaki

    2007-12-01

    The cells of the marine bacterium strain C-21, which is phylogenetically closely related to Arenibacter troitsensis, accumulate iodine in the presence of glucose and iodide (I-). In this study, the detailed mechanism of iodine uptake by C-21 was determined using a radioactive iodide tracer, 125I-. In addition to glucose, oxygen and calcium ions were also required for the uptake of iodine. The uptake was not inhibited or was only partially inhibited by various metabolic inhibitors, whereas reducing agents and catalase strongly inhibited the uptake. When exogenous glucose oxidase was added to the cell suspension, enhanced uptake of iodine was observed. The uptake occurred even in the absence of glucose and oxygen if hydrogen peroxide was added to the cell suspension. Significant activity of glucose oxidase was found in the crude extracts of C-21, and it was located mainly in the membrane fraction. These findings indicate that hydrogen peroxide produced by glucose oxidase plays a key role in the uptake of iodine. Furthermore, enzymatic oxidation of iodide strongly stimulated iodine uptake in the absence of glucose. Based on these results, the mechanism was considered to consist of oxidation of iodide to hypoiodous acid by hydrogen peroxide, followed by passive translocation of this uncharged iodine species across the cell membrane. Interestingly, such a mechanism of iodine uptake is similar to that observed in iodine-accumulating marine algae.

  1. Dense nonaqueous phase liquid tracer tests: experimental results.

    PubMed

    Burt, R A; Christians, G L; Williams, S P; Wilson, D J

    2001-12-01

    Two dense nonaqueous phase liquid (DNAPL) tracer tests were carried out in a shallow aquifer north of Fort Worth, TX. i-Propanol was used as the nonpartitioning tracer: n-hexanol and n-octanol were the partitioning tracers. Field data, mathematical modeling, the results of column tests, and field tracer tests with NaCl were used in designing the DNAPL tracer tests. The results indicated the presence of DNAPL at both sites tested; semi-quantitative estimates of the amounts of DNAPL present were obtained by mathematical modeling. Interpretation was complicated by heterogeneity of the aquifer and mass transport effects.

  2. Interpreting tracer breakthrough tailing from different forced-gradient tracer experiment configurations in fractured bedrock

    USGS Publications Warehouse

    Becker, M.W.; Shapiro, A.M.

    2003-01-01

    Conceptual and mathematical models are presented that explain tracer breakthrough tailing in the absence of significant matrix diffusion. Model predictions are compared to field results from radially convergent, weak-dipole, and push-pull tracer experiments conducted in a saturated crystalline bedrock. The models are based upon the assumption that flow is highly channelized, that the mass of tracer in a channel is proportional to the cube of the mean channel aperture, and the mean transport time in the channel is related to the square of the mean channel aperture. These models predict the consistent -2 straight line power law slope observed in breakthrough from radially convergent and weak-dipole tracer experiments and the variable straight line power law slope observed in push-pull tracer experiments with varying injection volumes. The power law breakthrough slope is predicted in the absence of matrix diffusion. A comparison of tracer experiments in which the flow field was reversed to those in which it was not indicates that the apparent dispersion in the breakthrough curve is partially reversible. We hypothesize that the observed breakthrough tailing is due to a combination of local hydrodynamic dispersion, which always increases in the direction of fluid velocity, and heterogeneous advection, which is partially reversed when the flow field is reversed. In spite of our attempt to account for heterogeneous advection using a multipath approach, a much smaller estimate of hydrodynamic dispersivity was obtained from push-pull experiments than from radially convergent or weak dipole experiments. These results suggest that although we can explain breakthrough tailing as an advective phenomenon, we cannot ignore the relationship between hydrodynamic dispersion and flow field geometry at this site. The design of the tracer experiment can severely impact the estimation of hydrodynamic dispersion and matrix diffusion in highly heterogeneous geologic media.

  3. Abnormal pressure in hydrocarbon environments

    USGS Publications Warehouse

    Law, B.E.; Spencer, C.W.

    1998-01-01

    Abnormal pressures, pressures above or below hydrostatic pressures, occur on all continents in a wide range of geological conditions. According to a survey of published literature on abnormal pressures, compaction disequilibrium and hydrocarbon generation are the two most commonly cited causes of abnormally high pressure in petroleum provinces. In young (Tertiary) deltaic sequences, compaction disequilibrium is the dominant cause of abnormal pressure. In older (pre-Tertiary) lithified rocks, hydrocarbon generation, aquathermal expansion, and tectonics are most often cited as the causes of abnormal pressure. The association of abnormal pressures with hydrocarbon accumulations is statistically significant. Within abnormally pressured reservoirs, empirical evidence indicates that the bulk of economically recoverable oil and gas occurs in reservoirs with pressure gradients less than 0.75 psi/ft (17.4 kPa/m) and there is very little production potential from reservoirs that exceed 0.85 psi/ft (19.6 kPa/m). Abnormally pressured rocks are also commonly associated with unconventional gas accumulations where the pressuring phase is gas of either a thermal or microbial origin. In underpressured, thermally mature rocks, the affected reservoirs have most often experienced a significant cooling history and probably evolved from an originally overpressured system.

  4. Systemic abnormalities in liver disease

    PubMed Central

    Minemura, Masami; Tajiri, Kazuto; Shimizu, Yukihiro

    2009-01-01

    Systemic abnormalities often occur in patients with liver disease. In particular, cardiopulmonary or renal diseases accompanied by advanced liver disease can be serious and may determine the quality of life and prognosis of patients. Therefore, both hepatologists and non-hepatologists should pay attention to such abnormalities in the management of patients with liver diseases. PMID:19554648

  5. Gallium uptake in tryptophan-related pulmonary disease

    SciTech Connect

    Kim, S.M.; Park, C.H.; Intenzo, C.M.; Patel, R. )

    1991-02-01

    We describe a patient who developed fever, fatigue, muscle weakness, dyspnea, skin rash, and eosinophilia after taking high doses of tryptophan for insomnia for two years. A gallium-67 scan revealed diffuse increased uptake in the lung and no abnormal uptake in the muscular distribution. Bronchoscopy and biopsy confirmed inflammatory reactions with infiltration by eosinophils, mast cells, and lymphocytes. CT scan showed an interstitial alveolar pattern without fibrosis. EMG demonstrated diffuse myopathy. Muscle biopsy from the right thigh showed an inflammatory myositis with eosinophilic and lymphocytic infiltrations.

  6. Factors influencing the uptake of nutrients in streams within the New York City water-supply source areas.

    NASA Astrophysics Data System (ADS)

    Newbold, D.; Kaplan, L.; Bott, T.; Jackson, J.; Aufdenkampe, A.; Dow, C.

    2005-05-01

    The uptake of nutrients was measured in each of ten streams within the water supply source areas for New York City, once each year between 2000 and 2002. Uptake lengths were estimated from the conservative-tracer-corrected downstream attenuation of short-term (1-2 h) nutrient releases. Uptake lengths correlated with stream size and were converted to uptake velocities (Vf) for further analysis. Vf of phosphate, with a mean of 0.018 mm/s, fit Michaelis-Menten uptake kinetics with a half-saturation of 7 μg/L background phosphate. Vf of ammonium, with a mean of 0.58 mm/s, did not correlate with background ammonium concentration, but fit an uptake curve that used total dissolved nitrogen as the substrate, with a half-saturation of 1 mg/L. Vf of glucose and arabinose were not related to background concentrations. Vf for all four nutrients correlated with community respiration (CR) from diel oxygen variation. For phosphorus uptake, however, CR was collinear with background phosphorus. Vf for ammonium correlated with the macroinvertebrate-based Water Quality Score and Vf for both ammonium and phosphate correlated with some molecular tracers of anthropogenic sources. These results point to nutrient uptake as a sensitive integrator of water quality, ecosystem metabolism, and community structure.

  7. Dispersion in the Surfzone: Tracer Dispersion Studies

    DTIC Science & Technology

    2011-09-30

    objective is to improve understanding and modeling of dispersion of tracers (pol­ lution, fecal indicator bacteria, fine sediments) within the...discussed further here. Stochastic Particle Simulation for Surfzone Dispersion Drifter-derived diffusivities are time-dependent. In an unbounded...diffusion. Here HB06 particle trajectories are stochastically simulated with the Langevin equations with a shoreline boundary to explain the observed

  8. Arctic ocean ventilation studied with a suite of anthropogenic halocarbon tracers.

    PubMed

    Krysell, M; Wallace, D W

    1988-11-04

    The chlorofluoromethanes (CFMs: CCl(2)F(2) and CCl(3)F), methyl chloroform (CH(3)CCl(3)), and carbon tetrachloride (CCl(4)) have been measured in deep waters of the Arctic Ocean. Oceanic and atmospheric inventories of these compounds result from known anthropogenic releases; because the CFMs and CCl(4) are also chemically nonreactive, they can be used as transient tracers of ocean circulation. The input history of CCl(4) is longer than that of any other transient tracer identified to date( approximately 70 years). This long input history, together with an e-folding time scale of increase(tau) of approximately 28 years, makes CCl(4) potentially the most useful tracer for calibrating models of the oceanic uptake of the fossil-fuel CO(2) transient(tau approximately 25 years). The bottom water of the Nansen Basin, Arctic Ocean, has detectable CCl(4) but undetectable CFM(s) and CH(3)CCl(3), which suggests either that the bottom water is approximately 50 years old, or that there is a small, nonanthropogenic component of atmospheric CCl(4)(<6 parts per trillion by volume).

  9. Transport of fluorobenzoate tracers in a vegetated hydrologic control volume: 2. Theoretical inferences and modeling

    NASA Astrophysics Data System (ADS)

    Queloz, Pierre; Carraro, Luca; Benettin, Paolo; Botter, Gianluca; Rinaldo, Andrea; Bertuzzo, Enrico

    2015-04-01

    A theoretical analysis of transport in a controlled hydrologic volume, inclusive of two willow trees and forced by erratic water inputs, is carried out contrasting the experimental data described in a companion paper. The data refer to the hydrologic transport in a large lysimeter of different fluorobenzoic acids seen as tracers. Export of solute is modeled through a recently developed framework which accounts for nonstationary travel time distributions where we parameterize how output fluxes (namely, discharge and evapotranspiration) sample the available water ages in storage. The relevance of this work lies in the study of hydrologic drivers of the nonstationary character of residence and travel time distributions, whose definition and computation shape this theoretical transport study. Our results show that a large fraction of the different behaviors exhibited by the tracers may be charged to the variability of the hydrologic forcings experienced after the injection. Moreover, the results highlight the crucial, and often overlooked, role of evapotranspiration and plant uptake in determining the transport of water and solutes. This application also suggests that the ways evapotranspiration selects water with different ages in storage can be inferred through model calibration contrasting only tracer concentrations in the discharge. A view on upscaled transport volumes like hillslopes or catchments is maintained throughout the paper.

  10. Transport of fluorobenzoate tracers in a vegetated hydrologic control volume: 1. Experimental results

    NASA Astrophysics Data System (ADS)

    Queloz, Pierre; Bertuzzo, Enrico; Carraro, Luca; Botter, Gianluca; Miglietta, Franco; Rao, P. S. C.; Rinaldo, Andrea

    2015-04-01

    This paper reports about the experimental evidence collected on the transport of five fluorobenzoate tracers injected under controlled conditions in a vegetated hydrologic volume, a large lysimeter (fitted with load cells, sampling ports, and an underground chamber) where two willows prompting large evapotranspiration fluxes had been grown. The relevance of the study lies in the direct and indirect measures of the ways in which hydrologic fluxes, in this case, evapotranspiration from the upper surface and discharge from the bottom drainage, sample water and solutes in storage at different times under variable hydrologic forcings. Methods involve the accurate control of hydrologic inputs and outputs and a large number of suitable chemical analyses of water samples in discharge waters. Mass extraction from biomass has also been performed ex post. The results of the 2 year long experiment established that our initial premises on the tracers' behavior, known to be sorption-free under saturated conditions which we verified in column leaching tests, were unsuitable as large differences in mass recovery appeared. Issues on reactivity thus arose and were addressed in the paper, in this case attributed to microbial degradation and solute plant uptake. Our results suggest previously unknown features of fluorobenzoate compounds as hydrologic tracers, potentially interesting for catchment studies owing to their suitability for distinguishable multiple injections, and an outlook on direct experimental closures of mass balance in hydrologic transport volumes involving fluxes that are likely to sample differently stored water and solutes.

  11. Tracer-based Metabolomics: Concepts and Practices

    PubMed Central

    Lee, W-N. Paul; Wahjudi, Paulin N.; Xu, Jun; Go, Vay Liang

    2010-01-01

    Tracer-based metabolomics is a systems biology tool that combines advances in tracer methodology for physiological studies, high throughput “-omics” technologies and constraint based modeling of metabolic networks. It is different from the commonly known metabolomics or metabonomics in that it is a targeted approach based on a metabolic network model in cells. Because of its complexity, it is the least understood among the various “-omics”. In this review, the development of concepts and practices of tracer-based metabolomics is traced from the early application of radioactive isotopes in metabolic studies to the recent application of stable isotopes and isotopomer analysis using mass spectrometry; and from the modeling of biochemical reactions using flux analysis to the recent theoretical formulation of the constraint based modeling. How these newer experimental methods and concepts of constraint-based modeling approaches can be applied to metabolic studies is illustrated by examples of studies in determining metabolic responses of cells to pharmacological agents and nutrient environment changes. PMID:20713038

  12. Stream Ammonium Uptake Across Scales in Headwater Catchments of a Tropical Rainforest, Luquillo Mountains, Puerto Rico

    NASA Astrophysics Data System (ADS)

    Brereton, R. L.; McDowell, W. H.; Wymore, A.

    2015-12-01

    Many tropical forest streams export high amounts of nitrogen relative to streams draining undisturbed watersheds of other biomes. With their low DOC concentrations and high rates of respiration, headwater streams in the Luquillo Mountains have been previously characterized as energy-limited, suggesting that NH4+ uptake is dominated not by N demand but by energy demand. In the Rio Icacos watershed, high concentrations of NH4+ (>1 mg N/L) are found in groundwater adjacent to the streams, making high inputs of NH4+ to the stream channel via groundwater seepage likely. Stream nutrient spiraling metrics can be used to quantify uptake and retention rates of specific nutrients, and can be measured by solute additions. Tracer Additions for Spiraling Curve Characterization (TASCC) is a recently developed method (Covino et al. 2010) for quantifying nutrient uptake with a single slug addition of nutrient and conservative tracer. Here we present NH4+ uptake metrics from TASCC additions in three Luquillo streams of different sizes, ranging from 2nd to 4th order: the Rio Icacos, a larger, 3rd order tributary and a smaller 2nd order tributary. Background NH4+ concentrations vary by up to an order of magnitude, with highest concentrations (27 μg N/L) found in the smaller tributary. Background DOC concentrations are uniformly low and show no difference between the three streams (500-600 μg C/L). The smaller tributary has the shortest uptake length (155 m) and highest uptake velocity (2.9 mm/min) of the three streams. Unexpectedly, the Rio Icacos has a higher uptake velocity (1.7 mm/min) than the larger tributary (1.0 mm/min), despite having an uptake length more than double (1400 m) that of the larger tributary (596 m). Overall, NH4+ uptake is substantial in all three streams and varies with background concentrations, not stream size.

  13. Salt marsh ecosystem biogeochemical responses to nutrient enrichment: a paired 15N tracer study.

    PubMed

    Drake, D C; Peterson, Bruce J; Galván, Kari A; Deegan, Linda A; Hopkinson, Charles; Johnson, J Michael; Koop-Jakobsen, K; Lemay, Lynsey E; Picard, Christian

    2009-09-01

    We compared processing and fate of dissolved NO3- in two New England salt marsh ecosystems, one receiving natural flood tide concentrations of approximately 1-4 micromol NO3-/ L and the other receiving experimentally fertilized flood tides containing approximately 70-100 micromol NO3-/ L. We conducted simultaneous 15NO3- (isotope) tracer additions from 23 to 28 July 2005 in the reference (8.4 ha) and fertilized (12.4 ha) systems to compare N dynamics and fate. Two full tidal cycles were intensively studied during the paired tracer additions. Resulting mass balances showed that essentially 100% (0.48-0.61 mol NO3-N.ha(-1).h(-1)) of incoming NO3- was assimilated, dissimilated, sorbed, or sedimented (processed) within a few hours in the reference system when NO3- concentrations were 1.3-1.8 micromol/L. In contrast, only 50-60% of incoming NO3- was processed in the fertilized system when NO3- concentrations were 84-96 micromol/L; the remainder was exported in ebb tidewater. Gross NO3- processing was approximately 40 times higher in the fertilized system at 19.34-24.67 mol NO3-N.ha(-1).h(-1). Dissimilatory nitrate reduction to ammonium was evident in both systems during the first 48 h of the tracer additions but <1% of incoming 15NO3- was exported as 15NH4+. Nitrification rates calculated by 15NO3- dilution were 6.05 and 4.46 mol.ha(-1).h(-1) in the fertilized system but could not be accurately calculated in the reference system due to rapid (<4 h) NO3- turnover. Over the five-day paired tracer addition, sediments sequestered a small fraction of incoming NO3-, although the efficiency of sequestration was 3.8% in the reference system and 0.7% in the fertilized system. Gross sediment N sequestration rates were similar at 13.5 and 12.6 mol.ha(-1).d(-1), respectively. Macrophyte NO3- uptake efficiency, based on tracer incorporation in aboveground tissues, was considerably higher in the reference system (16.8%) than the fertilized system (2.6%), although bulk uptake of NO3

  14. Tumor-Specific Uptake of Fluorescent Bevacizumab-IRDye800CW Microdosing in Patients with Primary Breast Cancer: A Phase I Feasibility Study.

    PubMed

    Lamberts, Laetitia E; Koch, Maximillian; de Jong, Johannes S; Adams, Arthur L L; Glatz, Jürgen; Kranendonk, Mariëtte E G; Terwisscha van Scheltinga, Anton G T; Jansen, Liesbeth; de Vries, Jakob; Lub-de Hooge, Marjolijn N; Schröder, Carolien P; Jorritsma-Smit, Annelies; Linssen, Matthijs D; de Boer, Esther; van der Vegt, Bert; Nagengast, Wouter B; Elias, Sjoerd G; Oliveira, Sabrina; Witkamp, Arjen J; Mali, Willem P Th M; Van der Wall, Elsken; van Diest, Paul J; de Vries, Elisabeth G E; Ntziachristos, Vasilis; van Dam, Gooitzen M

    2016-11-09

    Purpose: To provide proof of principle of safety, breast tumor-specific uptake, and positive tumor margin assessment of the systemically administered near-infrared fluorescent tracer bevacizumab-IRDye800CW targeting VEGF-A in patients with breast cancer.Experimental Design: Twenty patients with primary invasive breast cancer eligible for primary surgery received 4.5 mg bevacizumab-IRDye800CW as intravenous bolus injection. Safety aspects were assessed as well as tracer uptake and tumor delineation during surgery and ex vivo in surgical specimens using an optical imaging system. Ex vivo multiplexed histopathology analyses were performed for evaluation of biodistribution of tracer uptake and coregistration of tumor tissue and healthy tissue.Results: None of the patients experienced adverse events. Tracer levels in primary tumor tissue were higher compared with those in the tumor margin (P < 0.05) and healthy tissue (P < 0.0001). VEGF-A tumor levels also correlated with tracer levels (r = 0.63, P < 0.0002). All but one tumor showed specific tracer uptake. Two of 20 surgically excised lumps contained microscopic positive margins detected ex vivo by fluorescent macro- and microscopy and confirmed at the cellular level.Conclusions: Our study shows that systemic administration of the bevacizumab-IRDye800CW tracer is safe for breast cancer guidance and confirms tumor and tumor margin uptake as evaluated by a systematic validation methodology. The findings are a step toward a phase II dose-finding study aimed at in vivo margin assessment and point to a novel drug assessment tool that provides a detailed picture of drug distribution in the tumor tissue. Clin Cancer Res; 1-12. ©2016 AACR.

  15. The simultaneous uptake of dietary and waterborne Cd in gastrointestinal tracts of marine yellowstripe goby Mugilogobius chulae.

    PubMed

    Guo, Zhiqiang; Gao, Na; Wu, Yun; Zhang, Li

    2017-04-01

    Aquatic animals under waterborne metal exposure are also very likely exposed to elevated dietary metals. This study quantified the simultaneous uptake of dietary and waterborne Cd in gastrointestinal tracts (GT) of marine yellowstripe goby using a dual stable isotope tracer method. The Cd spiked diet (10-100 μg g(-1), (111)Cd as tracers) were fed to the fish as a single meal, and then the fish were exposed to waterborne Cd (0-500 μg L(-1), (113)Cd as tracers) for 48 h, during which the time-course uptake of Cd in the stomach and intestine was determined. The findings revealed that the dietary Cd uptake mainly occurred within 12 h after feeding. The fish exposed to 500 μg L(-1) waterborne Cd showed significantly lower Cd assimilation efficiency (2.07%) than the control group (3.48%) at the dietary Cd of 100 μg g(-1). Moreover, during 4-12 h when there was chyme in the GT, the waterborne Cd uptake in the intestine was lowest but the stomach showed the highest waterborne Cd uptake rate. The uptake of dietary and waterborne Cd, and the relative importance of dietary vs waterborne Cd was positively correlated with the Cd concentration in the chyme. Overall, this research demonstrated that there was interaction between dietary and waterborne Cd uptake in the GT of marine fish. The simultaneous uptake of metal from two routes is far more complex than the situation of a single route of metal uptake, which should be evaluated in determining metal bioaccumulation and toxicity in both laboratory and field metal exposure scenario.

  16. Using trees to remediate tritium contaminated groundwater: a modeling and tracer study.

    SciTech Connect

    Rebel, Karin, Theodora

    2004-01-01

    Rebel, Karin, T. 2004. Using trees to remediate tritium contaminated groundwater: a modeling and tracer study. Ph.D Dissertation. Cotnell University. Ithaca, New York. 174 pp. Abstract: We have developed a spatially explicit model of water and tritium fluxes in the vadose zone in order to simulate water uptake and subsurface lateral movement in coniferous and mixed hardwood - coniferous forests on Coastal Plain soils of the southern United States. These Coastal Plain soils are characteristically sand overlying slowly permeable clays found at depths of 30 to 200 cm, and can form temporarily saturated, unconfined aquifers. Ten hectares of the modeled watershed was periodically irrigated with tritium enriched water. We used the tritium enriched water as a tracer to validate the model. The model was used to optimize irrigation, to evaluate the amount of tritium entering the atmosphere due to evapotranspiration and to quantify water and tritium fluxes in texture contrast soils. Using tritium as a tracer, we have studied how tree species and canopy position effect water and solutes uptake from different parts of the soil profile. We clipped branches to obtain leaf water from over-and understory laurel oak (Quercus Laurifolia) and over- and understory pine (Pinus elliottii and Pinus taeda), which was then analyzed for tritium. We found that for early successional trees (Pinus spp.) and trees in the overstory proportionally more water was taken up from deeper in the soil compared to the hardwoods or trees in the understory, which took up proportionally more water from the soil surface. These differences are important for understanding competition for resources within a forest and in predicting the hydrologic response to forest management practices such as thinning.

  17. Asian Tracer Experiment and Atmospheric Modeling (TEAM) Project: Draft Field Work Plan for the Asian Long-Range Tracer Experiment

    SciTech Connect

    Allwine, K Jerry; Flaherty, Julia E.

    2007-08-01

    This report provides an experimental plan for a proposed Asian long-range tracer study as part of the international Tracer Experiment and Atmospheric Modeling (TEAM) Project. The TEAM partners are China, Japan, South Korea and the United States. Optimal times of year to conduct the study, meteorological measurements needed, proposed tracer release locations, proposed tracer sampling locations and the proposed durations of tracer releases and subsequent sampling are given. Also given are the activities necessary to prepare for the study and the schedule for completing the preparation activities leading to conducting the actual field operations. This report is intended to provide the TEAM members with the information necessary for planning and conducting the Asian long-range tracer study. The experimental plan is proposed, at this time, to describe the efforts necessary to conduct the Asian long-range tracer study, and the plan will undoubtedly be revised and refined as the planning goes forward over the next year.

  18. Chromosomal abnormalities and mental illness.

    PubMed

    MacIntyre, D J; Blackwood, D H R; Porteous, D J; Pickard, B S; Muir, W J

    2003-03-01

    Linkage studies of mental illness have provided suggestive evidence of susceptibility loci over many broad chromosomal regions. Pinpointing causative gene mutations by conventional linkage strategies alone is problematic. The breakpoints of chromosomal abnormalities occurring in patients with mental illness may be more direct pointers to the relevant gene locus. Publications that describe patients where chromosomal abnormalities co-exist with mental illness are reviewed along with supporting evidence that this may amount to an association. Chromosomal abnormalities are considered to be of possible significance if (a) the abnormality is rare and there are independent reports of its coexistence with psychiatric illness, or (b) there is colocalisation of the abnormality with a region of suggestive linkage findings, or (c) there is an apparent cosegregation of the abnormality with psychiatric illness within the individual's family. Breakpoints have been described within many of the loci suggested by linkage studies and these findings support the hypothesis that shared susceptibility factors for schizophrenia and bipolar disorder may exist. If these abnormalities directly disrupt coding regions, then combining molecular genetic breakpoint cloning with bioinformatic sequence analysis may be a method of rapidly identifying candidate genes. Full karyotyping of individuals with psychotic illness especially where this coexists with mild learning disability, dysmorphism or a strong family history of mental disorder is encouraged.

  19. Chromosomal abnormalities in human sperm

    SciTech Connect

    Martin, R.H.

    1985-01-01

    The ability to analyze human sperm chromosome complements after penetration of zona pellucida-free hamster eggs provides the first opportunity to study the frequency and type of chromosomal abnormalities in human gametes. Two large-scale studies have provided information on normal men. We have studied 1,426 sperm complements from 45 normal men and found an abnormality rate of 8.9%. Brandriff et al. (5) found 8.1% abnormal complements in 909 sperm from 4 men. The distribution of numerical and structural abnormalities was markedly dissimilar in the 2 studies. The frequency of aneuploidy was 5% in our sample and only 1.6% in Brandriff's, perhaps reflecting individual variability among donors. The frequency of 24,YY sperm was low: 0/1,426 and 1/909. This suggests that the estimates of nondisjunction based on fluorescent Y body data (1% to 5%) are not accurate. We have also studied men at increased risk of sperm chromosomal abnormalities. The frequency of chromosomally unbalanced sperm in 6 men heterozygous for structural abnormalities varied dramatically: 77% for t11;22, 32% for t6;14, 19% for t5;18, 13% for t14;21, and 0% for inv 3 and 7. We have also studied 13 cancer patients before and after radiotherapy and demonstrated a significant dose-dependent increase of sperm chromosome abnormalities (numerical and structural) 36 months after radiation treatment.

  20. Haematological abnormalities in mitochondrial disorders

    PubMed Central

    Finsterer, Josef; Frank, Marlies

    2015-01-01

    INTRODUCTION This study aimed to assess the kind of haematological abnormalities that are present in patients with mitochondrial disorders (MIDs) and the frequency of their occurrence. METHODS The blood cell counts of a cohort of patients with syndromic and non-syndromic MIDs were retrospectively reviewed. MIDs were classified as ‘definite’, ‘probable’ or ‘possible’ according to clinical presentation, instrumental findings, immunohistological findings on muscle biopsy, biochemical abnormalities of the respiratory chain and/or the results of genetic studies. Patients who had medical conditions other than MID that account for the haematological abnormalities were excluded. RESULTS A total of 46 patients (‘definite’ = 5; ‘probable’ = 9; ‘possible’ = 32) had haematological abnormalities attributable to MIDs. The most frequent haematological abnormality in patients with MIDs was anaemia. 27 patients had anaemia as their sole haematological problem. Anaemia was associated with thrombopenia (n = 4), thrombocytosis (n = 2), leucopenia (n = 2), and eosinophilia (n = 1). Anaemia was hypochromic and normocytic in 27 patients, hypochromic and microcytic in six patients, hyperchromic and macrocytic in two patients, and normochromic and microcytic in one patient. Among the 46 patients with a mitochondrial haematological abnormality, 78.3% had anaemia, 13.0% had thrombopenia, 8.7% had leucopenia and 8.7% had eosinophilia, alone or in combination with other haematological abnormalities. CONCLUSION MID should be considered if a patient’s abnormal blood cell counts (particularly those associated with anaemia, thrombopenia, leucopenia or eosinophilia) cannot be explained by established causes. Abnormal blood cell counts may be the sole manifestation of MID or a collateral feature of a multisystem problem. PMID:26243978

  1. Imaging regional renal function parameters using radionuclide tracers

    NASA Astrophysics Data System (ADS)

    Qiao, Yi

    A compartmental model is given for evaluating kidney function accurately and noninvasively. This model is cast into a parallel multi-compartment structure and each pixel region (picture element) of kidneys is considered as a single kidney compartment. The loss of radionuclide tracers from the blood to the kidney and from the kidney to the bladder are modelled in great detail. Both the uptake function and the excretion function of the kidneys can be evaluated pixel by pixel, and regional diagnostic information on renal function is obtained. Gamma Camera image data are required by this model and a screening test based renal function measurement is provided. The regional blood background is subtracted from the kidney region of interest (ROI) and the kidney regional rate constants are estimated analytically using the Kuhn-Pucker multiplier method in convex programming by considering the input/output behavior of the kidney compartments. The detailed physiological model of the peripheral compartments of the system, which is not available for most radionuclide tracers, is not required in the determination of the kidney regional rate constants and the regional blood background factors within the kidney ROI. Moreover, the statistical significance of measurements is considered to assure the improved statistical properties of the estimated kidney rate constants. The relations between various renal function parameters and the kidney rate constants are established. Multiple renal function measurements can be found from the renal compartmental model. The blood radioactivity curve and the regional (or total) radiorenogram determining the regional (or total) summed behavior of the kidneys are obtained analytically with the consideration of the statistical significance of measurements using convex programming methods for a single peripheral compartment system. In addition, a new technique for the determination of 'initial conditions' in both the blood compartment and the kidney

  2. (11)C-Methionine uptake in secondary brain epilepsy.

    PubMed

    Lopci, E; Bello, L; Chiti, A

    2014-01-01

    Carbon-11 methionine ((11)C-Methionine) is a radio-labeled amino acid currently utilized in Positron Emission Tomography (PET) for imaging primary and metastatic brain tumors. Its clinical use relies mostly on oncologic applications, but the tracer has the potential to investigate other non-malignant conditions. So far, very limited evidence concerns the use of (11)C-Methionine in patients suffering from seizure; however, the tracer can find a proper utilization in this setting especially as a diagnostic complement to (18)F-Fluorodeoxyglucose ((18)F-FDG). Herein we report the case of a 57-year-old patient presenting with epileptic crises secondary to a brain metastasis from bladder carcinoma, who was investigated in our institution with (11)C-Methionine PET. The scan documented the disease recurrence in the left parietal lobe associated with a diffused tracer uptake in the surrounding cerebral circumvolutions, derived from the comitial status. After surgical removal of the metastatic lesion, the patient experienced a complete recovery of symptoms and no further onset of secondary seizure.

  3. Hyperpolarized Functional Magnetic Resonance of Murine Skeletal Muscle Enabled by Multiple Tracer-Paradigm Synchronizations

    PubMed Central

    Leftin, Avigdor; Roussel, Tangi; Frydman, Lucio

    2014-01-01

    Measuring metabolism's time- and space-dependent responses upon stimulation lies at the core of functional magnetic resonance imaging. While focusing on water's sole resonance, further insight could arise from monitoring the temporal responses arising from the metabolites themselves, in what is known as functional magnetic resonance spectroscopy. Performing these measurements in real time, however, is severely challenged by the short functional timescales and low concentrations of natural metabolites. Dissolution dynamic nuclear polarization is an emerging technique that can potentially alleviate this, as it provides a massive sensitivity enhancement allowing one to probe low-concentration tracers and products in a single-scan. Still, conventional implementations of this hyperpolarization approach are not immediately amenable to the repeated acquisitions needed in real-time functional settings. This work proposes a strategy for functional magnetic resonance of hyperpolarized metabolites that bypasses this limitation, and enables the observation of real-time metabolic changes through the synchronization of stimuli-triggered, multiple-bolus injections of the metabolic tracer 13C1-pyruvate. This new approach is demonstrated with paradigms tailored to reveal in vivo thresholds of murine hind-limb skeletal muscle activation, involving the conversion of 13C1-pyruvate to 13C1-lactate and 13C1-alanine. These functional hind-limb studies revealed that graded skeletal muscle stimulation causes commensurate increases in glycolytic metabolism in a frequency- and amplitude-dependent fashion, that can be monitored on the seconds/minutes timescale using dissolution dynamic nuclear polarization. Spectroscopic imaging further allowed the in vivo visualization of uptake, transformation and distribution of the tracer and products, in fast-twitch glycolytic and in slow-twitch oxidative muscle fiber groups. While these studies open vistas in time and sensitivity for metabolic

  4. Hyperpolarized functional magnetic resonance of murine skeletal muscle enabled by multiple tracer-paradigm synchronizations.

    PubMed

    Leftin, Avigdor; Roussel, Tangi; Frydman, Lucio

    2014-01-01

    Measuring metabolism's time- and space-dependent responses upon stimulation lies at the core of functional magnetic resonance imaging. While focusing on water's sole resonance, further insight could arise from monitoring the temporal responses arising from the metabolites themselves, in what is known as functional magnetic resonance spectroscopy. Performing these measurements in real time, however, is severely challenged by the short functional timescales and low concentrations of natural metabolites. Dissolution dynamic nuclear polarization is an emerging technique that can potentially alleviate this, as it provides a massive sensitivity enhancement allowing one to probe low-concentration tracers and products in a single-scan. Still, conventional implementations of this hyperpolarization approach are not immediately amenable to the repeated acquisitions needed in real-time functional settings. This work proposes a strategy for functional magnetic resonance of hyperpolarized metabolites that bypasses this limitation, and enables the observation of real-time metabolic changes through the synchronization of stimuli-triggered, multiple-bolus injections of the metabolic tracer 13C1-pyruvate. This new approach is demonstrated with paradigms tailored to reveal in vivo thresholds of murine hind-limb skeletal muscle activation, involving the conversion of 13C1-pyruvate to 13C1-lactate and 13C1-alanine. These functional hind-limb studies revealed that graded skeletal muscle stimulation causes commensurate increases in glycolytic metabolism in a frequency- and amplitude-dependent fashion, that can be monitored on the seconds/minutes timescale using dissolution dynamic nuclear polarization. Spectroscopic imaging further allowed the in vivo visualization of uptake, transformation and distribution of the tracer and products, in fast-twitch glycolytic and in slow-twitch oxidative muscle fiber groups. While these studies open vistas in time and sensitivity for metabolic

  5. The Potential of Carbonyl Sulfide as a Tracer for Gross Primary Productivity at Flux Tower Sites

    NASA Astrophysics Data System (ADS)

    Blonquist, J.; Montzka, S. A.; Yakir, D.; Desai, A. R.; Dragoni, D.; Griffis, T. J.; Monson, R. K.; Munger, J. W.; Scott, R. L.; Bowling, D. R.

    2010-12-01

    Regional/continental scale studies of atmospheric carbonyl sulfide (OCS) seasonal dynamics and leaf level studies of plant OCS uptake have shown a close relationship to CO2 dynamics and uptake, suggesting potential for OCS as a tracer for gross primary productivity (GPP). Canopy CO2 and OCS differences (mole fraction within canopy minus that above canopy) at a temperate deciduous forest (Harvard Forest AmeriFlux site) were analyzed relative to net ecosystem exchange (NEE) and GPP, respectively. Canopy CO2 and OCS vertical gradients (CO2 and OCS differences divided by within and above canopy measurement height differences) were used to calculate ecosystem relative uptake (ERU; relative canopy OCS gradient divided by relative canopy CO2 gradient, where relative gradients are gradients normalized by above canopy mole fractions), from which GPP was estimated using an equation that assumes OCS follows the same physical pathway as CO2 into plant leaves and where GPP / NEE was proportional to OCS gradient / CO2 gradient. Additionally, canopy CO2 differences from five other AmeriFlux sites were analyzed, and OCS differences were projected from these differences (via an assumed ERU) to further evaluate OCS as a potential GPP tracer. At Harvard Forest, canopy CO2 differences were related to NEE (y = 0.041x + 0.046, r2 = 0.14, P < 0.025) and OCS differences were related to GPP (y = 0.43x - 2.0, r2 = 0.18, P < 0.1), indicating the influence of canopy uptake on canopy differences. Relative canopy OCS and CO2 gradients were linearly correlated (slope = 4.4, intercept = -0.00028, r2 = 0.69, P < 0.025), indicating CO2 and OCS dynamics were likely controlled by similar mechanisms. Estimates of GPP derived from OCS and from temperature-based NEE partitioning showed a strong linear relationship (slope = 1.2, intercept = 3.1, r2 = 0.99, P < 0.0005), indicating the potential of OCS as a GPP tracer. As with Harvard Forest, canopy CO2 differences at the other AmeriFlux sites were related

  6. Monocyte transferrin-iron uptake in hereditary hemochromatosis

    SciTech Connect

    Sizemore, D.J.; Bassett, M.L.

    1984-05-01

    Transferrin-iron uptake by peripheral blood monocytes was studied in vitro to test the hypothesis that the relative paucity of mononuclear phagocyte iron loading in hereditary hemochromatosis results from a defect in uptake of iron from transferrin. Monocytes from nine control subjects and 17 patients with hemochromatosis were cultured in the presence of 59Fe-labelled human transferrin. There was no difference in 59Fe uptake between monocytes from control subjects and monocytes from patients with hemochromatosis who had been treated by phlebotomy and who had normal body iron stores. However, 59Fe uptake by monocytes from iron-loaded patients with hemochromatosis was significantly reduced compared with either control subjects or treated hemochromatosis patients. It is likely that this was a secondary effect of iron loading since iron uptake by monocytes from treated hemochromatosis patients was normal. Assuming that monocytes in culture reflect mononuclear phagocyte iron metabolism in vivo, this study suggests that the relative paucity of mononuclear phagocyte iron loading in hemochromatosis is not related to an abnormality in transferrin-iron uptake by these cells.

  7. [Differential diagnosis of reduced uptake images revealed by bone scan: about a case of acute lymphoblastic leukemia].

    PubMed

    Bahadi, Nisrine; Biyi, Abdelhamid; Oueriagli, Salah Nabih; Doudouh, Abderrahim

    2016-01-01

    If increased uptake during bone scan usually bring to light many bone pathologies, reduced uptakes are a rare occurrence and they require careful analysis to avoid erroneous interpretations. We report the case of a 17-year old admitted with diffuse bone pain, hypercalcemia and thrombopenia. Bone scan showed areas of low uptakes. Bone marrow tests allowed the diagnosis of acute lymphoblastic leukemia. This case report aims to discuss the main differential diagnoses based on such bone scan abnormalities.

  8. Fetal glucose uptake and utilization as functions of maternal glucose concentration.

    PubMed

    Hay, W W; Sparks, J W; Wilkening, R B; Battaglia, F C; Meschia, G

    1984-03-01

    Seventeen studies were performed in 12 pregnant sheep to examine the relationship among simultaneously measured glucose uptake via the umbilical circulation, fetal glucose utilization (mg X min-1 X kg-1), and maternal arterial glucose (Gm, mg/dl). Fetal glucose utilization was measured by means of tracer glucose infused into the fetus or both mother and fetus. By fasting the ewe, Gm was varied in the 62-22 range. A decrease in Gm was accompanied by a significant (P less than 0.001) decrease in umbilical uptake (uptake = 0.09 Gm - 0.96, r = 0.82) and in fetal utilization, measured either by [U-14C]glucose (utilization = 0.062 Gm + 0.91, r = 0.90) or [6-3H]glucose (utilization = 0.065 Gm + 0.51, r = 0.91). At uptake greater than 3 mg X min-1 X kg-1, utilization and uptake were not significantly different. At lower uptakes, utilization did not decline as much as uptake. The results demonstrate that maternal fasting decreases both the umbilical uptake and the fetal utilization of glucose and suggest that fetal glucogenesis increases when the availability of exogenous glucose is markedly reduced.

  9. Brain uptake of iomazenil in cirrhotic patients: a single photon emission tomography study.

    PubMed

    Kapczinski, F; Quevedo, J; Curran, H V; Fleminger, S; Toone, B; Cluckie, A; Lader, M

    1999-01-01

    Brain uptake of 123I-iomazenil was studied in seven cirrhotic patients and eight normal controls using single photon emission computerized tomography. The highest concentration of the ligand was found in the occipital cortex, which corresponds to the brain region with the highest concentration of benzodiazepine receptors. The peak uptake was delayed in patients across all brain regions. The uptake in occipital cortex was higher in low albumin cirrhotics. Patients with low albumin also presented a more delayed peak uptake in occipital cortex and a higher volume of distribution of iomazenil in plasma, compared to patients with normal albumin levels and controls. The changes in brain uptake (delayed peak uptake and increased maximal uptake in occipital cortex) appears to reflect changes in the pharmacokinetics of the ligand, particularly in cirrhotics with low levels of plasma albumin. The curve of brain uptake of the tracer was modelled into a two compartments equation, which seems to provide a practical and reliable method to calculate the slopes of acquisition and decay, time to peak and maximal acquisition.

  10. The role of new PET tracers for lung cancer.

    PubMed

    Szyszko, Teresa A; Yip, Connie; Szlosarek, Peter; Goh, Vicky; Cook, Gary J R

    2016-04-01

    18F-fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET/CT) is established for characterising indeterminate pulmonary nodules and staging lung cancer where there is curative intent. Whilst a sensitive technique, specificity for characterising lung cancer is limited. There is recognition that evaluation of other aspects of abnormal cancer biology in addition to glucose metabolism may be more helpful in characterising tumours and predicting response to novel targeted cancer therapeutics. Therefore, efforts have been made to develop and evaluate new radiopharmaceuticals in order to improve the sensitivity and specificity of PET imaging in lung cancer with regards to characterisation, treatment stratification and therapeutic monitoring. 18F-fluorothymidine (18F-FLT) is a marker of cellular proliferation. It shows a lower accumulation in tumours than 18F-FDG as it only accumulates in the cells that are in the S phase of growth and demonstrates a low sensitivity for nodal staging. Its main role is in evaluating treatment response. Methionine is an essential amino acid. 11C-methionine is more specific and sensitive than 18F-FDG in differentiating benign and malignant thoracic nodules. 18Ffluoromisonidazole (18F-FMISO) is used for imaging tumour hypoxia. Tumour response to treatment is significantly related to the level of tumour oxygenation. Angiogenesis is the process by which new blood vessels are formed in tumours and is involved in tumour growth and metastatic tumour spread and is a therapeutic target. Most clinical studies have focused on targeted integrin PET imaging of which αvβ3 integrin is the most extensively investigated. It is upregulated on activated endothelial cells in association with tumour angiogenesis. Neuroendocrine tumour tracers, particularly 68Ga-DOTA-peptides, have an established role in imaging of carcinoid tumours. Whilst most of these tracers have predominantly been used in the research environment, they offer

  11. Cholangiolocellular Carcinoma of the Liver Exhibiting High F-18 FDG Uptake.

    PubMed

    Mori, Naoko; Ichikawa, Tamaki; Hashimoto, Jun; Yamashita, Tomohiro; Yamada, Misuzu; Hirabayashi, Kenichi; Imai, Yutaka

    2016-06-20

    Cholangiolocellular carcinoma (CoCC) is a rare primary liver cancer. It is considered to originate from hepatic progenitor or stem cells. We report a rare case of a 74-year-old male with CoCC of the liver and duodenal gastrointestinal stromal tumor (GIST). Both tumors manifested tracer uptakes on F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT); however, the uptake in hepatic tumor was extremely higher than that in the duodenal tumor. This finding was helpful to exclude the metastasis of GIST.

  12. Congenital abnormalities and selective abortion.

    PubMed

    Seller, M J

    1976-09-01

    The technique of amniocentesis, by which an abnormal fetus can be detected in utero, has brought a technological advance in medical science but attendant medical and moral problems. Dr Seller describes those congenital disabilities which can be detected in the fetus before birth, for which the "remedy" is selective abortion. She then discusses the arguments for and against selective abortion, for the issue is not simple, even in the strictly genetic sense of attempting to ensure a population free of congenital abnormality.

  13. Tracer Transport in the Middle Atmosphere

    NASA Astrophysics Data System (ADS)

    Arnold, Neil F.

    1990-01-01

    Available from UMI in association with The British Library. Requires signed TDF. The discovery of the ozone 'hole' over Antarctica has stimulated a great deal of interest in the interaction between dynamics, radiation and chemistry in the middle atmosphere. In this thesis, a hierarchy of tracer transport models has been adopted to help to understand the results of satellite observations and detailed computer simulations. Zonally averaged models have met with some success in simulating the atmosphere because it is close to radiative/chemical equilibrium in the summer. A zonally averaged circulation derived from satellite observations of temperature and ozone was used here to test various advection schemes and to reproduce the zonal mean seasonal cycle of long-lived tropospheric source gases. Three-dimensional models impose more severe demands and so a number of finite difference schemes have been reviewed and tested under idealized atmospheric conditions. To reduce the computational effort, winds were generated by the Meteorological Office Stratosphere Mesosphere model (SMM) and passed to a transport model. The best transport scheme was the one which most closely resembled that used for heat and momentum transport. Time averaging of the winds was necessary to produce representative fields in the mesosphere. When the transport scheme was incorporated into the SMM, agreement between the dynamically derived potential temperature and potential vorticity and the tracer equivalents were very good. During a major warming, the discrepancy between the vortex maximum between the model potential vorticity and the equivalent material tracer fields was 12% in the middle stratosphere and 50% in the upper stratosphere after twenty days. Most of this difference was due to the sensitivity of the potential vorticity to diabatic heating. Extensions of the work to include chemistry and more sophisticated satellite-derived circulations were suggested.

  14. Uptake of HNO3 to Deliquescent Sea-Salt and Mineral Dust Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Guimbaud, C.; Vlassenko, A.; Gaggeler, H.; Ammann, M.

    2002-12-01

    Uptake of HNO3 to aerosol particles is an important removal pathway of nitrogen oxides in the troposphere. Uptake of HNO3 to deliquescent sea-salt aerosol particles was studied in an aerosol flow reactor. Submicron sea-salt particles were used to avoid diffusion limitation in the gas-phase at atmospheric pressure. To overcome the sensitivity problems associated with low amount of reactants processed in such low aerosol masses, we used the short-lived radioactive tracer 13N to label the trace gas molecules at very low concentration. Uptake of HNO3 to deliquescent sea-salt particles was studied under a wide range of HNO3 concentration. Between 1 and 60 ppbv, the uptake coefficient was constant at 0.5+/-0.2 within the first few seconds, whereas at higher concentrations of about 600ppbv, the uptake coefficient rapidly dropped to 0.1 after about 1 second. This drop was due to complete release of chloride as HCl. The equilibrium conditions for these experiments were explored using the North American Aerosol Inorganics (AIM) model, which accounts for the activities of the concentrated solution of the deliquescent aerosol. It is concluded that the rates of uptake at low concentration were limited by the mass accommodation coefficient as both the diffusion in the liquid phase or the rate of release of HCl were not rate limiting. Using an identical approach, we started to investigate the uptake of HNO3 to mineral dust aerosol particles in a similar flow reactor, and first results will be presented. References Ammann, M, Using 13N as tracer in heterogeneous atmospheric chemistry experiments, Radiochim. Acta., 89, 831-838, 2001 Guimbaud, C., F., Arens, L., Gutzwiller, H.W, Gäggeler, and M. Ammann, Uptake of HNO3 to Deliquescent Sea-Salt Aerosol Particles, Atmos. Chem. Phys. Discuss., 2, 739-763, 2002

  15. Radon as a Tracer for Lunar Volatiles

    NASA Technical Reports Server (NTRS)

    Friesen, Larry Jay

    1992-01-01

    Radon and its decay product polonium can be used as tracers to search for lunar volatiles. One effective technique to look for them would be by using alpha-particle spectrometers from lunar orbit. Alpha spectrometers were flown in the Apollo Service Modules during the Apollo 15 and 16 missions, and did observe Rn-222 and its decay product Po-210 on the lunar surface from orbit. This demonstrates that radon and polonium can be observed from orbit; what must next be shown is that such observations can reveal something about the locations of volatiles on the Moon.

  16. Radon as a tracer for lunar volatiles

    NASA Astrophysics Data System (ADS)

    Friesen, Larry Jay

    Radon and its decay product polonium can be used as tracers to search for lunar volatiles. One effective technique to look for them would be by using alpha-particle spectrometers from lunar orbit. Alpha spectrometers were flown in the Apollo Service Modules during the Apollo 15 and 16 missions, and did observe Rn-222 and its decay product Po-210 on the lunar surface from orbit. This demonstrates that radon and polonium can be observed from orbit; what must next be shown is that such observations can reveal something about the locations of volatiles on the Moon.

  17. Pharmaceuticals as Groundwater Tracers - Applications and Limitations

    NASA Astrophysics Data System (ADS)

    Scheytt, T. J.; Mersmann, P.; Heberer, T.

    2003-12-01

    Pharmaceutically active substances and metabolites are found at concentrations up to the microgram/L-level in groundwater samples from the Berlin (Germany) area and from several other places world wide. Among the compounds detected in groundwater are clofibric acid, propyphenazone, diclofenac, ibuprofen, and carbamazepine. Clofibric acid, the active metabolite of clofibrate and etofibrate (blood lipid regulators) is detected in groundwater at maximum concentrations of 7300 ng/L. Among the most important input paths of drugs are excretion and disposal into the sewage system. Groundwater contamination is likely to be due to leaky sewage systems, influent streams, bank filtration, and irrigation with effluent water from sewage treatment plants. There are no known natural sources of the above mentioned pharmaceuticals. The use of pharmaceuticals as tracers may include: (a) Quantification of infiltration from underground septic tanks (b) Detection of leaky sewage systems / leaky sewage pipes (c) Estimation of the effectiveness of sewage treatment plants (d) Identification of transport pathways of other organic compounds (e) Quantification of surface water / groundwater interaction (f) Characterization of the biodegradation potential. The use of pharmaceuticals as tracers is limited by variations in input. These variations depend on the amount of drugs prescribed and used in the study area, the social structure of the community, the amount of hospital discharge, and temporal concentration variations. Furthermore, the analysis of trace amounts of pharmaceuticals is sophisticated and expensive and may therefore limit the applicability of pharmaceuticals as tracers. Finally, the transport and degradation behavior of pharmaceuticals is not fully understood. Preliminary experiments in the laboratory were conducted using sediment material and groundwater from the Berlin area to evaluate the transport and sorption behavior of selected drugs. Results of the column experiments

  18. Gallium-67 uptake by a benign adrenocortical adenoma

    SciTech Connect

    Jackson, J.A.; Naul, L.G.; Montgomery, J.L.; Carpentier, W.R.; Roberts, J.W.

    1988-08-01

    A 55-yr-old man presented with an atypical relapsing meningitis and was found to have intense unilateral adrenal uptake by /sup 67/Ga imaging. Computed tomography showed a 4-cm right adrenal mass which was hypointense on the T1-weighted images and mildly hyperintense on the T2-weighted images of a magnetic resonance (MR) scan. At surgery, a coincidental benign adrenocortical adenoma was found. Because /sup 67/Ga uptake is usually associated with inflammatory or malignant lesions and malignant adrenal lesions are hyperintense on T2-weighted MR images, these findings contributed to diagnostic uncertainty in this patient. Thus, a nonhyperfunctional adrenocortical adenoma may be associated with abnormal /sup 67/Ga uptake and atypical MR findings.

  19. Determination of stream reaeration coefficients by use of tracers

    USGS Publications Warehouse

    Kilpatrick, F.A.; Rathbun, R.E.; Yotsukura, Nobuhiro; Parker, G.W.; DeLong, L.L.

    1987-01-01

    Stream reaeration is the physical absorption of oxygen from the atmosphere by a flowing stream. This is the primary process by which a stream replenishes the oxygen consumed in the biodegradation of organic wastes. Prior to 1965, reaeration rate coefficients could be estimated only by indirect methods. In 1965, a direct method of measuring stream reaeration coefficients was developed in which a radioactive tracer gas was injected into a stream--the tracer gas being desorbed from the stream inversely to how oxygen would be absorbed. The technique has since been modified by substituting hydrocarbon gases for the radioactive tracer gas. The slug-injection and constant-rate injection methods of performing gas tracer desorption measurements are described. Emphasis is on the use of rhodamine WT dye as a relatively conservative tracer and propane as the nonconservative gas tracer, on planning field tests, methods of injection, sampling and analysis, and computational techniques to compute desorption and reaeration coefficients. (Author 's abstract)

  20. Inositol uptake in rat aorta

    SciTech Connect

    Rapoport, R.M.; Van Gorp, C.; Chang, Ki-Churl )

    1990-01-01

    {sup 3}H-inositol uptake into deendothelialized aorta was linear for at least 2 h and was composed of both a saturable, Na{sup +}-dependent, and a nonsaturable, Na{sup +}-independent component. The Na{sup +}-dependent component of inositol uptake had a K{sub m} of 50 {mu}M and a V{sub max} of 289 pmol/mg prot/h. Exposure to LiCl, ouabain, or Ca{sup 2+} - free Krebs-Ringer bicarbonate solution inhibited uptake. Metabolic poisoning with dinitrophenol, as well as incubation with phloretin, an inhibitor of carrier-mediated hexose transport, also inhibited uptake. Exposure to norepinephrine decreased inositol uptake, while phorbol myristate acetate was without effect. Isobutylmethylxanthine significantly increased inositol uptake, while the increased uptake due to dibutyryl cyclic AMP and forskolin were not statistically significant. Sodium nitroprusside, and activator of guanylate cyclase, and 8-bromo cyclic GMP, were without effect on uptake, as was methylene blue, an inhibitor of guanylate cyclase. Inositol uptake into the aorta was increased when the endothelium was allowed to remain intact, although this effect was likely due to uptake in both the endothelial and smooth muscle cells.

  1. Lidar Tracking of Multiple Fluorescent Tracers: Method and Field Test

    NASA Technical Reports Server (NTRS)

    Eberhard, Wynn L.; Willis, Ron J.

    1992-01-01

    Past research and applications have demonstrated the advantages and usefulness of lidar detection of a single fluorescent tracer to track air motions. Earlier researchers performed an analytical study that showed good potential for lidar discrimination and tracking of two or three different fluorescent tracers at the same time. The present paper summarizes the multiple fluorescent tracer method, discusses its expected advantages and problems, and describes our field test of this new technique.

  2. Tracer Migration in a Radially Divergent Flow Field: Longitudinal Dispersivity and Anionic Tracer Retardation

    SciTech Connect

    Seaman, J.C., P.M. Bertsch, M. Wilson, J. Singer, F. Majs and S.A. Aburime

    2007-01-01

    Hydrodynamic dispersion, the combined effects of chemical diffusion and differences in solute path length and flow velocity, is an important factor controlling contaminant migration in the subsurface environment. However, few comprehensive three-dimensional datasets exist for critically evaluating the impact of travel distance and site heterogeneity on solute dispersion, and the conservative nature of several commonly used groundwater tracers is still in question. Therefore, we conducted a series of field-scale experiments using tritiated water ({sup 3}H{sup 1}HO), bromide (Br{sup -}), and two fluorobenzoates (2,4 Di-FBA, 2,6 Di-FBA) as tracers in the water-table aquifer on the USDOE's Savannah River Site (SRS), located on the upper Atlantic Coastal Plain. For each experiment, tracer-free groundwater was injected for approximately 24 h (56.7 L min{sup -1}) to establish a steady-state forced radial gradient before the introduction of a tracer pulse. After the tracer pulse, which lasted from 256 to 560 min, the forced gradient was maintained throughout the experiment using nonlabeled groundwater. Tracer migration was monitored using six multilevel monitoring wells, radially spaced at approximate distances of 2.0, 3.0, and 4.5 m from the central injection well. Each sampling well was further divided into three discrete sampling depths that were pumped continuously ({approx}0.1 L min{sup -1}) throughout the course of the experiments. Longitudinal dispersivity ({alpha}{sub L}) and travel times for {sup 3}H{sup 1}HO breakthrough were estimated by fitting the field data to analytical approximations of the advection-dispersion equation (ADE) for uniform and radial flow conditions. Dispersivity varied greatly between wells located at similar transport distances and even between zones within a given well, which we attributed to variability in the hydraulic conductivity at the study site. The radial flow equation generally described tritium breakthrough better than the

  3. [Diagnosticum of abnormalities of plant meiotic division].

    PubMed

    Shamina, N V

    2006-01-01

    Abnormalities of plant meiotic division leading to abnormal meiotic products are summarized schematically in the paper. Causes of formation of monads, abnormal diads, triads, pentads, polyads, etc. have been observed in meiosis with both successive and simultaneous cytokinesis.

  4. Imaging the Normal and Abnormal Anatomy of the Female Pelvis Using (18)F FDG-PET/CT, Including Pitfalls and Artifacts.

    PubMed

    Even-Sapir, Einat

    2010-10-01

    This article summarizes the normal biodistribution of (18)F fluorodeoxyglucose in the pelvis, physiologic changes in the female reproductive system and benign adnexal and uterine lesions which may be associated with increased tracer uptake that should be appreciated when PET/CT studies of female patients, mainly those with gynecologic malignancies are reviewed.

  5. PET Tracers Based on Zirconium-89

    PubMed Central

    Zhang, Yin; Hong, Hao; Cai, Weibo

    2011-01-01

    Positron emission tomography (PET) imaging with radiolabeled monoclonal antibodies has always been a dynamic area in molecular imaging. With decay half-life (3.3 d) well matched to the circulation half-lives of antibodies (usually on the order of days), 89Zr has been extensively studied over the last decade. This review article will give a brief overview on 89Zr isotope production, the radiochemistry generally used for 89Zr-labeling, and the PET tracers that have been developed using 89Zr. To date, 89Zr-based PET imaging has been investigated for a wide variety of cancer-related targets, which include human epidermal growth factor receptor 2, epidermal growth factor receptor, prostate-specific membrane antigen, splice variant v6 of CD44, vascular endothelial growth factor, carbonic anhydrase IX, insulin-like growth factor 1 receptor, among others. With well-developed radiochemistry, commercial availability of chelating agents for 89Zr labeling, increasingly widely available isotope supply, as well as successful proof-of-principle in pilot human studies, it is expected that PET imaging with 89Zr-based tracers will be a constantly evolving and highly vibrant field in the near future. PMID:22191652

  6. Tracers and Modeling (Paper 7R0316)

    NASA Astrophysics Data System (ADS)

    Sarmiento, J. L.

    1987-07-01

    The major tracer activity of the last four years was the completion in 1983 of a survey of the North and Tropical Atlantic begun in 1981 as part of the Transient Tracers in the Ocean (TTO) project (Brewer, et al., 1985). An early set of papers (Brewer et al., 1983, and Swift, 1984) discussed evidence from these observations for the freshening of the North Atlantic due to cessation of overflow across the Iceland-Scotland ridge in the period between Geosecs and TTO. Broecker et al. (1985a) examined observations further south within the deep Northeastern Atlantic and showed that there was no change of nutrient contents in this region during the same time span, consistent with their conclusion that there is no ventilation of this region from the north. Kawase and Sarmiento (1985 and 1986) used the TTO data to produce a series of nutrient and salinity maps and property-property plots on density surfaces in the thermocline and middepth waters. Of particular interest in these studies is the evidence from silica-salinity observations of strong cross-isopycnal mixing and advection in the equatorial region.

  7. Tracer exchange between tropics and middle latitudes

    NASA Technical Reports Server (NTRS)

    Rood, Richard; Douglass, Anne; Weaver, Clark

    1992-01-01

    The interaction between the tropics and middle latitudes is studied using a tracer emitted at 50 hPa along a great circle route between Los Angeles, USA and Sydney, Australia. Though designed to examine the impact of stratospheric aircraft, the study more generally addresses the transport between tropics and middle latitudes for a three month period from January through March 1989. The results show that air is transported from the tropics to middle latitudes by planetary scale and tropospheric cyclonic scale waves. Except for intrusions by these wave events, the tropics are substantially isolated throughout the lower stratosphere. These waves draw material out of the tropics which ends up in the middle latitude westerly jets, with little material entering the winter polar latitudes prior to the springtime transition. The summer Southern Hemisphere is characterized by tracer being drawn out in streamers that extend from north and west to south and east. The material in the tropics is zonally asymmetric. The material that reaches the troposphere comes down in the synoptic scale eddies and is concentrated in the middle latitude jet stream. These characteristics are similar to those observed during the dispersion of volcanic clouds.

  8. Progress in isotope tracer hydrology in Canada

    NASA Astrophysics Data System (ADS)

    Gibson, J. J.; Edwards, T. W. D.; Birks, S. J.; St Amour, N. A.; Buhay, W. M.; McEachern, P.; Wolfe, B. B.; Peters, D. L.

    2005-01-01

    An overview of current research in isotope hydrology, focusing on recent Canadian contributions, is discussed under the headings: precipitation networks, hydrograph separation and groundwater studies, river basin hydrology, lake and catchment water balance, and isotope palaeohydrology from lake sediment records. Tracer-based techniques, relying primarily on the naturally occurring environmental isotopes, have been integrated into a range of hydrological and biogeochemical research programmes, as they effectively complement physical and chemical techniques. A significant geographic focus of Canadian isotope hydrology research has been on the Mackenzie River basin, forming contributions to programmes such as the Global Energy and Water Cycle Experiment. Canadian research has also directly supported international efforts such as the International Atomic Energy Agency's (IAEA) Global Network for Isotopes in Precipitation and IAEAs Coordinated Research Project on Large River Basins. One significant trend in Canadian research is toward sustained long-term monitoring of precipitation and river discharge to enable better characterization of spatial and temporal variability in isotope signatures and their underlying causes. One fundamental conclusion drawn from previous studies in Canada is that combined use of 18O and 2H enables the distinction of precipitation variability from evaporation effects, which offers significant advantages over use of the individual tracers alone. The study of hydrological controls on water chemistry is one emerging research trend that stems from the unique ability to integrate isotope sampling within both water quality and water quantity surveys. Copyright

  9. How to chase a tracer - combining conventional salt tracer testing and direct push electrical conductivity profiling for enhanced aquifer characterization

    NASA Astrophysics Data System (ADS)

    Vienken, Thomas; Huber, Emanuel; Kreck, Manuel; Huggenberger, Peter; Dietrich, Peter

    2017-01-01

    Tracer testing is a well-established technique in hydrogeological site characterization. However, certain a priori knowledge of the hydraulic regime is required beforehand to avoid test failure, e.g. miss of tracer. In this study, we propose a novel tracer test concept for the hydraulic characterization of shallow unconsolidated sedimentary deposits when only scarce a priori information on the hydraulic regime is available. Therefore, we combine conventional salt tracer testing with direct push vertical high resolution electrical conductivity logging. The proposed tracer test concept was successfully tested on coarse, braided river deposits of the Tagliamento River, Italy. With limited a priori information available two tracer tests were performed in three days to reliably determine ground water flow direction and velocity allowing on-site decision-making to adaptively install observation wells for reliable breakthrough curve measurements. Furthermore, direct push vertical electrical profiling provided essential information about the plume characteristics with outstanding measurement resolution and efficiency.

  10. Transient Tracers in the Oceans (TTO) - hydrographic data and carbon dioxide systems with revised carbon chemistry data

    SciTech Connect

    Brewer, P.G.; Takahashi, T.; Williams, R.T.

    1986-09-01

    The Transient Tracers in the Ocean (TTO) study was an experiment to investigate ocean mixing as deduced from the distribution of radiochemical tracers introduced into the atmosphere and subsequently into the oceans during the 1958-1962 nuclear bomb tests. The results of this study together with knowledge about the chemistry of oceanic CO{sub 2} can be used to help understand oceanic uptake of fossil fuel CO{sub 2}. The experiment lasted 4 years and consisted of the following parts: (1) (1981); (3) laboratory analysis (1982); and (4) completion, data analysis, and reporting (1983). Shipboard measurements were published by the Scripps Physical and Chemical Oceanographic Data Facility as the T.T.O. Preliminary Hydrographic Data Reports Vols. I-IV. Recently, revisions to some of the previously reported measurements have been made and estimates of total CO{sub 2} have been calculated.

  11. Recent advances in developing COS as a tracer of Biosphere-atmosphere exchange of CO2

    NASA Astrophysics Data System (ADS)

    Asaf, D.; Stimler, K.; Yakir, D.

    2012-04-01

    Potential use of COS as tracer of CO2 flux into vegetation, based on its co-diffusion with CO2 into leaves without outflux, stimulated research on COS-CO2 interactions. Atmospheric measurements by NOAA in recent years, across a global latitudinal transect, indicated a ratio of the seasonal drawdowns in COS and CO2 (normalized to their respective ambient concentrations) of about 6. We carried out leaf-scale gas exchange measurements of COS and CO2 in 22 plant species of deciduous, evergreen trees, grasses, and shrubs, under a range of light intensities and ambient COS concentrations (using mid IR laser spectroscopy). A narrow range in the normalized ratio of the net uptake rates of COS and CO2 (termed leaf relative uptake; LRU) was observed with a mean value of 1.61±0.26. These results reflect the dominance of stomatal conductance over both COS and CO2 uptake, imposing a relatively constant ratio between the two fluxes, except under low light conditions when CO2, but not COS, metabolism is light limited. A relatively constant ratio under common ambient conditions will facilitate the application of COS as a tracer of gross photosynthesis from leaf to global scales. We also report first eddy flux measurements of COS/CO2 at the ecosystem scales. Preliminarily results indicate a ratio of the COS flux, Fcos, to net ecosystem CO2 exchange, NEE, of 3-5 (termed ecosystem relative uptake; ERU). Combining measurements of COS and CO2 and the new information on their ratios at different scales should permit the direct estimation of gross CO2 uptake, GPP, by land ecosystems according to: GPP=NEE*ERU/LRU. In addition, we show that COS effect on stomatal conductance may require a special attention. Increasing COS concentrations between 250 and 2800 pmol mol-1 (enveloping atmospheric levels) stimulate stomatal conductance. It seems likely that the stomata are responding to H2S produced in the leaves from COS.

  12. Gallium uptake in the thyroid gland in amiodarone-induced hyperthyroidism

    SciTech Connect

    Ling, M.C.; Dake, M.D.; Okerlund, M.D.

    1988-04-01

    Amiodarone is an iodinated antiarrhythmic agent that is effective in the treatment of atrial and ventricular arrhythmias. A number of side effects are seen, including pulmonary toxicity and thyroid dysfunction. A patient with both amiodarone-induced pneumonitis and hyperthyroidism who exhibited abnormal gallium activity in the lungs, as well as diffuse gallium uptake in the thyroid gland is presented. The latter has not been previously reported and supports the concept of iodide-induced thyroiditis with gallium uptake reflecting the inflammatory response.

  13. Recombinant glucose uptake system

    DOEpatents

    Ingrahm, Lonnie O.; Snoep, Jacob L.; Arfman, Nico

    1997-01-01

    Recombinant organisms are disclosed that contain a pathway for glucose uptake other than the pathway normally utilized by the host cell. In particular, the host cell is one in which glucose transport into the cell normally is coupled to PEP production. This host cell is transformed so that it uses an alternative pathway for glucose transport that is not coupled to PEP production. In a preferred embodiment, the host cell is a bacterium other than Z. mobilis that has been transformed to contain the glf and glk genes of Z. mobilis. By uncoupling glucose transport into the cell from PEP utilization, more PEP is produced for synthesis of products of commercial importance from a given quantity of biomass supplied to the host cells.

  14. Abnormal insulin levels and vertigo.

    PubMed

    Proctor, C A

    1981-10-01

    Fifty patients with unexplained vertigo (36) or lightheadedness (14) are evaluated, all of whom had abnormal ENGs and normal audiograms. Five hour insulin glucose tolerance tests were performance on all patients, with insulin levels being obtained fasting and at one-half, one, two, and three hours. The results of this investigation were remarkable. Borderline or abnormal insulin levels were discovered in 82% of patients; 90% were found to have either an abnormal glucose tolerance test or at least borderline insulin levels. The response to treatment in these dizzy patients was also startling, with appropriate low carbohydrate diets improving the patient's symptoms in 90% of cases. It is, therefore, apparent that the earliest identification of carbohydrate imbalance with an insulin glucose tolerance test is extremely important in the work-up of the dizzy patients.

  15. Complex patterns of abnormal heartbeats

    NASA Technical Reports Server (NTRS)

    Schulte-Frohlinde, Verena; Ashkenazy, Yosef; Goldberger, Ary L.; Ivanov, Plamen Ch; Costa, Madalena; Morley-Davies, Adrian; Stanley, H. Eugene; Glass, Leon

    2002-01-01

    Individuals having frequent abnormal heartbeats interspersed with normal heartbeats may be at an increased risk of sudden cardiac death. However, mechanistic understanding of such cardiac arrhythmias is limited. We present a visual and qualitative method to display statistical properties of abnormal heartbeats. We introduce dynamical "heartprints" which reveal characteristic patterns in long clinical records encompassing approximately 10(5) heartbeats and may provide information about underlying mechanisms. We test if these dynamics can be reproduced by model simulations in which abnormal heartbeats are generated (i) randomly, (ii) at a fixed time interval following a preceding normal heartbeat, or (iii) by an independent oscillator that may or may not interact with the normal heartbeat. We compare the results of these three models and test their limitations to comprehensively simulate the statistical features of selected clinical records. This work introduces methods that can be used to test mathematical models of arrhythmogenesis and to develop a new understanding of underlying electrophysiologic mechanisms of cardiac arrhythmia.

  16. Tracer Dispersion Within an Urban Environment.

    NASA Astrophysics Data System (ADS)

    Martin, D.; Shallcross, D.; Price, C.; Nickless, G.; Simmonds, P.

    2003-12-01

    The transport and dispersion of pollutants has extremely important implications for the environment on urban, regional and global scales. At the urban level localised emissions of both biogenic and anthropogenic pollutants can directly impact the health of the inhabitants. The DAPPLE (Dispersion of Air Pollutants and their Penetration into the Local Environment) project is a consortium of six universities, which involves a multidisciplinary approach to characterise relatively small-scale urban atmospheric dispersion including wind tunnel modelling, computer simulations, fieldwork and analysis. This work describes the tracer technology used to characterise atmospheric dispersion as well as preliminary results from the first tracer release experiment in Central London. A steady state finite duration release of both perfluoromethylcyclohexane (PMCH) and Sulfur Hexafluoride (SF6 ) was performed as part of the first DAPPLE campaign. These compounds were released over a fifteen-minute integrated time period with the SF6 release staggered one and a half minutes behind the PMCH. The low background concentrations of PMCH (~ 5 x 10-3 pptv) and SF6 (~5pptv) along with non-depositing and non-reactive characteristics allow for the implementation of near ideal fluid dynamic experiments. Sampling consists of a multiport ladder fitting with solenoid valves onto which a succession of sampling bags is attached. These are electrically actuated in sequential order with an integrated sampling time of three minutes. The samplers are placed at various receptor positions in the DAPPLE zone in predefined positions designed to best validate these model simulated meteorological dispersion processes. Analysis of PMCH is carried out using sample enrichment on carbon based adsorbents, separation by capillary Gas Chromatography and Negative Ion Chemical Ionisation Mass Spectrometry detection (GC-MS-NICI). SF6 concentrations are determined using fixed volume loop injections with Gas

  17. Ectodermal dysplasia and abnormal thumbs.

    PubMed

    Lucky, A W; Esterly, N B; Tunnessen, W W

    1980-05-01

    Two unrelated children, a girl and a boy, with alopecia, anomalous cutaneous pigmentation, abnormal thumbs, and endocrine disorders, including short stature and delayed bone age in one patient and juvenile onset diabetes mellitus in the other, are described. In one instance, the mother and the maternal grandmother had similar abnormalities, although of a less severe nature. Both children had normal nails and no unusual susceptibility to infections. We believe these two patients represent a previously undescribed syndrome of ectodermal dysplasia that may be inherited as an autosomal-dominant trait.

  18. In vivo characterization of insulin uptake by dog renal cortical epithelium

    SciTech Connect

    Whiteside, C.I.; Lumsden, C.J.; Silverman, M.

    1988-09-01

    In vivo 125I-labeled insulin uptake by dog renal tubular epithelium was studied using the single-pass multiple indicator dilution (MID) method and analyzed by a computer-assisted model of transcapillary exchange and substrate-cell interaction. Anesthetized dogs received an intrarenal arterial bolus of multiple tracers: (3H)dextran greater than 70 kDa (plasma reference), (14C)inulin (extracellular reference), and 125I-insulin. Rapid serial sampling of the renal venous and urine outflows was performed. The renal venous outflow curves of 125I-insulin fell below (14C)inulin implying postglomerular extraction and antiluminal membrane (ALM) uptake. The fractional urine recovery of 125I-insulin was less than 0.03, indicating luminal tubular uptake of filtered hormone. After intravenous infusion of unlabeled insulin, repeat MID runs with tracer revealed saturable ALM uptake as evidenced by the 125I-insulin renal venous outflow curves approaching (14C)inulin. Luminal tubular uptake was unchanged and therefore unsaturable. The 125I-insulin renal venous data were studied using three mathematical models, incorporating postglomerular reversible binding, irreversible binding or transport. The best fit was obtained using the transport model. The modeling analysis is consistent with either uptake into a virtual epithelial membrane space (i.e., insulin never enters the cell but binds to or is distributed along the ALM) or insulin actually enters the intracellular compartment. In vivo uptake of 125I-insulin ALM is characterized by a Km of 15.44 nM.

  19. Attempting to link hydro-morphology, transient storage and metabolism in streams: Insights from reactive tracer experiments

    NASA Astrophysics Data System (ADS)

    Kurz, Marie J.; Schmidt, Christian; Blaen, Phillip; Knapp, Julia L. A.; Drummond, Jennifer D.; Martí, Eugenia; Zarnetske, Jay P.; Ward, Adam S.; Krause, Stefan

    2016-04-01

    In-stream transient storage zones, including the hyporheic zone and vegetation beds, can be hotspots of biogeochemical processing in streams, enhancing ecosystem functions such as metabolism and nutrient uptake. The spatio-temporal dynamics and reactivity of these storage zones are influenced by multiple factors, including channel geomorphology, substrate composition and hydrology, and by anthropogenic modifications to flow regimes and nutrient loads. Tracer injections are a commonly employed method to evaluate solute transport and transient storage in streams; however, reactive tracers are needed to differentiate between metabolically active and inactive transient storage zones. The reactive stream tracer resazurin (Raz), a weakly fluorescent dye which irreversibly transforms to resorufin (Rru) under mildly reducing conditions, provides a proxy for aerobic respiration and an estimate of the metabolic activity associated with transient storage zones. Across a range of lotic ecosystems, we try to assess the influence of stream channel hydro-morphology, morphologic heterogeneity, and substrate type on reach (103 m) and sub-reach (102 m) scale transient storage, respiration, and nutrient uptake. To do so, we coupled injections of Raz and conservative tracers (uranine and/or salt) at each study site. The study sites included: vegetated mesocosms controlled for water depth; vegetated and un-vegetated sediment-filled mesocosms fed by waste-water effluent; a contrasting sand- vs. gravel-bedded lowland stream (Q = 0.08 m3/s); and a series of upland streams with varying size (Q = 0.1 - 1.5 m3/s) and prevalence of morphologic features. Continuous time-series of tracer concentrations were recorded using in-situ fluorometers and EC loggers. At the stream sites, time-series were recorded at multiple downstream locations in order to resolve sub-reach dynamics. Analyses yielded highly variable transport metrics and Raz-Rru transformation between study sites and between sub

  20. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  1. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  2. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  3. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  4. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  5. ANALYTICAL METHOD DEVELOPMENTS TO SUPPORT PARTITIONING INTERWELL TRACER TESTING

    EPA Science Inventory

    Partitioning Interwell Tracer Testing (PITT) uses alcohol tracer compounds in estimating subsurface contamination from non-polar pollutants. PITT uses the analysis of water samples for various alcohols as part of the overall measurement process. The water samples may contain many...

  6. Urban Pollutant Transport and Infiltration into Buildings Using Perfluorocarbon Tracers

    PubMed Central

    Matthews, James C.; Bacak, Asan; Khan, M. Anwar H.; Wright, Matthew D.; Priestley, Michael; Martin, Damien; Percival, Carl J.; Shallcross, Dudley E.

    2017-01-01

    People spend the majority of their time indoors and therefore the quality of indoor air is worthy of investigation; indoor air quality is affected by indoor sources of pollutants and from pollutants entering buildings from outdoors. In this study, unique perfluorocarbon tracers were released in five experiments at a 100 m and ~2 km distance from a large university building in Manchester, UK and tracer was also released inside the building to measure the amount of outdoor material penetrating into buildings and the flow of material within the building itself. Air samples of the tracer were taken in several rooms within the building, and a CO2 tracer was used within the building to estimate air-exchange rates. Air-exchange rates were found to vary between 0.57 and 10.90 per hour. Indoor perfluorocarbon tracer concentrations were paired to outdoor tracer concentrations, and in-out ratios were found to vary between 0.01 and 3.6. The largest room with the lowest air-exchange rate exhibited elevated tracer concentrations for over 60 min after the release had finished, but generally had the lowest concentrations, the room with the highest ventilation rates had the highest concentration over 30 min, but the peak decayed more rapidly. Tracer concentrations indoors compared to outdoors imply that pollutants remain within buildings after they have cleared outside, which must be considered when evaluating human exposure to outdoor pollutants. PMID:28230812

  7. Urban Pollutant Transport and Infiltration into Buildings Using Perfluorocarbon Tracers.

    PubMed

    Matthews, James C; Bacak, Asan; Khan, M Anwar H; Wright, Matthew D; Priestley, Michael; Martin, Damien; Percival, Carl J; Shallcross, Dudley E

    2017-02-21

    People spend the majority of their time indoors and therefore the quality of indoor air is worthy of investigation; indoor air quality is affected by indoor sources of pollutants and from pollutants entering buildings from outdoors. In this study, unique perfluorocarbon tracers were released in five experiments at a 100 m and ~2 km distance from a large university building in Manchester, UK and tracer was also released inside the building to measure the amount of outdoor material penetrating into buildings and the flow of material within the building itself. Air samples of the tracer were taken in several rooms within the building, and a CO₂ tracer was used within the building to estimate air-exchange rates. Air-exchange rates were found to vary between 0.57 and 10.90 per hour. Indoor perfluorocarbon tracer concentrations were paired to outdoor tracer concentrations, and in-out ratios were found to vary between 0.01 and 3.6. The largest room with the lowest air-exchange rate exhibited elevated tracer concentrations for over 60 min after the release had finished, but generally had the lowest concentrations, the room with the highest ventilation rates had the highest concentration over 30 min, but the peak decayed more rapidly. Tracer concentrations indoors compared to outdoors imply that pollutants remain within buildings after they have cleared outside, which must be considered when evaluating human exposure to outdoor pollutants.

  8. Tracer diffusion in silica inverse opals.

    PubMed

    Cherdhirankorn, Thipphaya; Retsch, Markus; Jonas, Ulrich; Butt, Hans-Juergen; Koynov, Kaloian

    2010-06-15

    We employed fluorescence correlation spectroscopy (FCS) to study the diffusion of small fluorescence tracers in liquid filled silica inverse opals. The inverse opals consisted of a nanoporous silica scaffold spanning a hexagonal crystal of spherical voids of 360 nm diameter connected by circular pores of 70 nm diameter. The diffusion of Alexa Fluor 488 in water and of perylene-3,4,9,10-tetracarboxylic diimide (PDI) in toluene was studied. Three diffusion modes could be distinguished: (1) Free diffusion limited by the geometric constraints given by the inverse opal, where, as compared to the free solution, this diffusion is slowed down by a factor of 3-4, (2) slow diffusion inside the nanoporous matrix of the silica scaffold, and (3) diffusion limited by adsorption. On the length scale of the focus of a confocal microscope of roughly 400 nm diffusion was non-Fickian in all cases.

  9. Tracer studies of nitrogen assimilation in yeast.

    PubMed

    ABRAMS, R; HAMMARSTEN, E

    1949-01-01

    By using N(15) as a tracer the assimilation of ammonia by the yeast, Torulopsis utilis, has been studied. It has been shown that: 1. There was no measurable incorporation of N in the protein or polynucleotide purine of carbon-starved yeast. 2. When ammonia is added to nitrogen-starved yeast there is a long lag period before division begins during which the yeast rapidly synthesizes protein, this process being accompanied by a turnover of polynucleotide purine. There was no significant dilution of the N(15)H(4) (+) of the medium by ordinary NH(4) (+). 3. When yeast containing N(15) is allowed to divide and grow in ordinary ammonia, the total amount of N(15) in the yeast remains constant. The dicarboxylic amino acids are most diluted, while arginine and nucleic acid guanine are not diluted at all.

  10. National Biomedical Tracer Facility. Project definition study

    SciTech Connect

    Schafer, R.

    1995-02-14

    We request a $25 million government-guaranteed, interest-free loan to be repaid over a 30-year period for construction and initial operations of a cyclotron-based National Biomedical Tracer Facility (NBTF) in North Central Texas. The NBTF will be co-located with a linear accelerator-based commercial radioisotope production facility, funded by the private sector at approximately $28 million. In addition, research radioisotope production by the NBTF will be coordinated through an association with an existing U.S. nuclear reactor center that will produce research and commercial radioisotopes through neutron reactions. The combined facilities will provide the full range of technology for radioisotope production and research: fast neutrons, thermal neutrons, and particle beams (H{sup -}, H{sup +}, and D{sup +}). The proposed NBTF facility includes an 80 MeV, 1 mA H{sup -} cyclotron that will produce proton-induced (neutron deficient) research isotopes.

  11. The random walk of tracers through river catchments

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Atreyee

    2012-08-01

    River catchments play critical roles in regional economies and in the global economy. In addition, rivers carry large volumes of nutrients, pollutants, and several other forms of tracers into the ocean. An intricate system of pathways and channels, both on the surface and in the subsurface of catchments, allows rivers to carry large volumes of tracers. However, scientists do not yet fully understand how pollutants and other tracers travel through the intricate web of channels in the catchment areas of rivers. In a new study, Cvetkovic et al show that the travel path of tracers through channels can be modeled as a random walk, which is mathematically similar to the path an animal would trace when foraging. Previous studies have applied the random walk approach to understand the behavior of fluids flowing through aquifers and soils but not to model the transport mechanism of tracers that travel passively with water flowing through catchments.

  12. Vestibular abnormalities in congenital disorders.

    PubMed

    Sando, I; Orita, Y; Miura, M; Balaban, C D

    2001-10-01

    This paper reviews the histopathologic features of vestibular abnormalities in congenital disorders affecting the inner ear, based upon a comprehensive literature survey and a review of cases in our temporal bone collection. The review proceeds in three systematic steps. First, we surveyed associated diseases with the major phenotypic features of congenital abnormalities of the inner ear (including the internal auditory canal and otic capsule). Second, the vestibular anomalies are examined specifically. Finally, the anomalies are discussed from a developmental perspective. Among vestibular anomalies, a hypoplastic endolymphatic duct and sac are observed most frequently. Anomalies of the semicircular canals are also often observed. From embryological and clinical viewpoints, many of these resemble the structural features from fetal stages and appear to be associated with vestibular dysfunction. It is expected that progress in genetic analysis and accumulation of temporal bone specimens with vestibular abnormalities in congenital diseases will provide crucial information not only for pathology of those diseases, but also for genetic factors that are responsible for the specific vestibular abnormalities.

  13. Effects of Submesoscale Ocean Turbulence on Buoyant and Passive Tracers

    NASA Astrophysics Data System (ADS)

    Smith, K.; Fox-Kemper, B.; Hamlington, P.

    2015-12-01

    Recent studies have shown that submesoscale processes greatly influence the dynamics and structure of the oceanic mixed layer. These processes have a substantial impact, in particular, on the transport of momentum, buoyancy, and passive tracers such as carbonate chemical species, nutrients, and plankton. It has been suggested that the vertical transfer of both active buoyancy and passive tracers can be described by the same vertical flux profile, thus permitting the use of one flux profile when parameterizing the effects of submoescale processes on tracer transport. Within the submesoscale range, however, both partly geostrophic fronts and eddies, which act to restratify the mixed layer, and small-scale three-dimensional turbulence, which acts to enhance vertical mixing, are simultaneously active, thus giving rise to complex multiscale interactions between turbulence and tracer dynamics. In this talk, large eddy simulations spanning the range of scales from 20km down to 5m are used to examine the role of multiscale turbulent mixing on both an active buoyancy tracer and several nonreactive passive ocean tracers from interior and sea-surface sources. The simulations include the effects of both small-scale wave-driven Langmuir turbulence and larger submesoscale eddies. Tracer properties are characterized using spatial fields and statistics, multiscale fluxes, and spectra. Results show that while submesoscale eddies transport buoyancy upward to extract potential energy, the same is not true of passive tracers. Instead, the suppression of turbulent vertical mixing in active submesoscale regions leads to suppressed entrainment of tracers, implying weaker transport by submesoscale activity. These results along with implications for the development of reduced order tracer models will be discussed.

  14. Methods and systems using encapsulated tracers and chemicals for reservoir interrogation and manipulation

    DOEpatents

    Roberts, Jeffery; Aines, Roger D; Duoss, Eric B; Spadaccini, Christopher M

    2014-11-04

    An apparatus, method, and system of reservoir interrogation. A tracer is encapsulating in a receptacle. The receptacle containing the tracer is injected into the reservoir. The tracer is analyzed for reservoir interrogation.

  15. Journal: Efficient Hydrologic Tracer-Test Design for Tracer-Mass Estimation and Sample Collection Frequency, 1 Method Development

    EPA Science Inventory

    Hydrological tracer testing is the most reliable diagnostic technique available for the determination of basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test design can be difficult because of a lack of prior knowl...

  16. Gallium-67 uptake by the thyroid associated with progressive systemic sclerosis

    SciTech Connect

    Sjoberg, R.J.; Blue, P.W.; Kidd, G.S.

    1989-01-01

    Although thyroidal uptake of gallium-67 has been described in several thyroid disorders, gallium-67 scanning is not commonly used in the evaluation of thyroid disease. Thyroidal gallium-67 uptake has been reported to occur frequently with subacute thyroiditis, anaplastic thyroid carcinoma, and thyroid lymphoma, and occasionally with Hashimoto's thyroiditis and follicular thyroid carcinoma. A patient is described with progressive systemic sclerosis who, while being scanned for possible active pulmonary involvement, was found incidentally to have abnormal gallium-67 uptake only in the thyroid gland. Fine needle aspiration cytology of the thyroid revealed Hashimoto's thyroiditis. Although Hashimoto's thyroiditis occurs with increased frequency in patients with progressive systemic sclerosis, thyroidal uptake of gallium-67 associated with progressive systemic sclerosis has not, to our knowledge, been previously described. Since aggressive thyroid malignancies frequently are imaged by gallium-67 scintigraphy, fine needle aspiration cytology of the thyroid often is essential in the evaluation of thyroidal gallium-67 uptake.

  17. Carbonyl sulfide as an inverse tracer for biogenic organic carbon in gas and aerosol phases

    NASA Astrophysics Data System (ADS)

    de Gouw, J. A.; Warneke, C.; Montzka, S. A.; Holloway, J. S.; Parrish, D. D.; Fehsenfeld, F. C.; Atlas, E. L.; Weber, R. J.; Flocke, F. M.

    2009-03-01

    Carbonyl sulfide (COS) is a long-lived trace gas in the atmosphere with an oceanic source and a surface sink through the uptake by vegetation and soils. We demonstrate the use of COS as an inverse tracer for the impact of biogenic emissions on an air mass including the formation of secondary organic aerosol (SOA). Using airborne data from the summer of 2004 over the northeastern U.S., we find that air masses with reduced COS in the continental boundary layer had on average higher mixing ratios of biogenic VOCs (isoprene, monoterpenes, methanol) and their photo-oxidation products (methacrolein, methyl vinyl ketone, methyl furan and MPAN, a peroxyacyl nitrate derived from isoprene). Measurements of water-soluble organic carbon were only weakly correlated with COS, indicating that SOA formation from biogenic precursors was a small contribution to the total.

  18. Steady-state and transient modeling of tracer and nutrient distributions in the global ocean

    SciTech Connect

    Stocker, T.F.; Broecker, W.S.

    1993-03-08

    The balance of stable and decaying tracers was incorporated into a latitude-depth ocean circulation model which resolves the major ocean basin and is coupled to an atmospheric energy balance model. The modern distribution of radiocarbon and the analysis of artificial color tracers enabled the census of the deep water masses. We show that good agreement with the observation can be achieved if the surface forcing is modified. The same process could also account for long-term, large-scale changes of the global thermohaline circulation. Uptake rates of carbon are investigated using an inorganic carbon cycle model and performing 2 [times] CO[sub 2]-experiments. We prescribe the industrial evolution of pCO[sub 2] in the atmosphere from 1792 to 1988 and calculate the total flux of carbon into the world ocean. Results are in good agreement with two recent 3-dimensional model simulation. First results using an organic carbon cycle in this model are presented. Changes in the hydrological cycle can stabilize the thermohaline circulation in the Atlantic and enable simulation of climate events resembling the Younger Dryas. By adding the balance of radiocarbon the evolution of its atmospheric concentration is studied during rapid changes of deep ocean ventilation. A resumption of ventilation creates a rapid decrease of atmospheric radiocarbon which is able to mask the natural decay.

  19. Modelling of a Tracer experiment (Bromide) at the lysimeter Wagna/Austria with MIKE-SHE

    NASA Astrophysics Data System (ADS)

    Reszler, Christian; Fank, Johann

    2015-04-01

    Data of a tracer experiment with Bromide at one of the three lysimeters in Wagna/Austria are used to test the unsaturated zone solute transport model in MIKE-SHE. On April 4th, 2005 50 mg/l of Bromide were applied on the lysimeter operated with conventional farming. At this time the lysimeter was covered with bare soil until the start of the cultivation of pumpkin one month later. Concentrations at the lysimeter bottom (180 cm depth) were measured and, after break-through, plant uptake was measured to quantify mass recovery. The model using the Richards-Van Genuchten-Mualem approach is setup by comprehensive data of vegetation and soil hydraulic properties available at the lysimeter. Water movement simulation in the unsaturated zone is tested against measured seepage rates at the lysimeter bottom and soil water contents in different soil depths in a period of five years. A sensitivity study shows that, particularly in the quaternary gravel zone two different parameter sets are necessary to represent the different dynamics of water content and seepage. With both two sets the general dynamics of the tracer experiment are simulated well. However, the early rapid rise of the measured concentrations could not be represented by either parameter set, which indicates a complex pore system consisting of different flow paths in the gravel zone, e.g., a system of matrix flow and macro-pore flow.

  20. Airborne measurements of acetonitrile and other organic tracers during MIRAGE- MEX

    NASA Astrophysics Data System (ADS)

    Apel, E. C.; Hills, A.; Emmons, L.; Orlando, J.; Riemer, D.; Sive, B.

    2007-05-01

    Biomass burning (BB) plumes are known to impact air quality throughout the globe and can be important sources of pollution in megacities. A number of chemical tracers for BB have been used in the recent past with acetonitrile, a long-lived (~6 months) organic trace gas, among them. However, the atmospheric budget of acetonitrile is not well-known. It has been accepted in the recent literature that the primary source for acetonitrile is from BB, but a recent study points to an oceanic source. Loss is believed to be by reaction with OH and oceanic uptake. Earlier studies indicated that acetonitrile may be produced in emissions from automobile exhaust but a study done in the late 1990s appeared to discredit this. We use measurements from the Trace Organic Gas Analyzer (TOGA) onboard the NCAR C-130 aircraft to investigate the sources and sinks of acetonitrile in and around the Mexico City Metropolitan Area, investigate its utility as a tracer of emissions, and present data on emissions characterization based on measurements of acetonitrile and other co-measured VOCs.

  1. Evaluating uncertainties in the calibration of isotopic reference materials and multi-element isotopic tracers (EARTHTIME Tracer Calibration Part II)

    NASA Astrophysics Data System (ADS)

    McLean, Noah M.; Condon, Daniel J.; Schoene, Blair; Bowring, Samuel A.

    2015-09-01

    A statistical approach to evaluating uncertainties in the calibration of multi-element isotopic tracers has been developed and applied to determining the isotopic composition of mixed U-Pb (202 Pb-205 Pb-233 U-235 U) tracers used for accurate isotope dilution U-Pb geochronology. Our experiment, part of the EARTHTIME initiative, directly links the tracer calibration to first-principles measurements of mass and purity that are all traceable to SI units, thereby quantifying the accuracy and precision of U-Pb dates in absolute time. The calibration incorporates new more accurate and precise purity measurements for a number of commonly used Pb and U reference materials, and requires inter-relating their isotopic compositions and uncertainties. Similar methods can be used for other isotope systems that utilize multiple isotopic standards for calibration purposes. We also detail the inter-calibration of three publicly available U-Pb gravimetric solutions, which can be used to bring the same first-principles traceability to in-house U-Pb tracers from other laboratories. Accounting for uncertainty correlations in the tracer isotope ratios yields a tracer calibration contribution to the relative uncertainty of a 206 Pb/238 U date that is only half of the relative uncertainty in the 235 U/205 Pb ratio of the tracer, which was historically used to approximate the tracer related uncertainty contribution to 206 Pb/238 U dates. The tracer uncertainty contribution to 206 Pb/238 U dates has in this way been reduced to <300 ppm when using the EARTHTIME and similarly calibrated tracers.

  2. A Standardized Method for the Construction of Tracer Specific PET and SPECT Rat Brain Templates: Validation and Implementation of a Toolbox

    PubMed Central

    Vállez Garcia, David; Casteels, Cindy; Schwarz, Adam J.; Dierckx, Rudi A. J. O.; Koole, Michel; Doorduin, Janine

    2015-01-01

    High-resolution anatomical image data in preclinical brain PET and SPECT studies is often not available, and inter-modality spatial normalization to an MRI brain template is frequently performed. However, this procedure can be challenging for tracers where substantial anatomical structures present limited tracer uptake. Therefore, we constructed and validated strain- and tracer-specific rat brain templates in Paxinos space to allow intra-modal registration. PET [18F]FDG, [11C]flumazenil, [11C]MeDAS, [11C]PK11195 and [11C]raclopride, and SPECT [99mTc]HMPAO brain scans were acquired from healthy male rats. Tracer-specific templates were constructed by averaging the scans, and by spatial normalization to a widely used MRI-based template. The added value of tracer-specific templates was evaluated by quantification of the residual error between original and realigned voxels after random misalignments of the data set. Additionally, the impact of strain differences, disease uptake patterns (focal and diffuse lesion), and the effect of image and template size on the registration errors were explored. Mean registration errors were 0.70±0.32mm for [18F]FDG (n = 25), 0.23±0.10mm for [11C]flumazenil (n = 13), 0.88±0.20 mm for [11C]MeDAS (n = 15), 0.64±0.28mm for [11C]PK11195 (n = 19), 0.34±0.15mm for [11C]raclopride (n = 6), and 0.40±0.13mm for [99mTc]HMPAO (n = 15). These values were smallest with tracer-specific templates, when compared to the use of [18F]FDG as reference template (p&0.001). Additionally, registration errors were smallest with strain-specific templates (p&0.05), and when images and templates had the same size (p≤0.001). Moreover, highest registration errors were found for the focal lesion group (p&0.005) and the diffuse lesion group (p = n.s.). In the voxel-based analysis, the reported coordinates of the focal lesion model are consistent with the stereotaxic injection procedure. The use of PET/SPECT strain- and tracer-specific templates allows

  3. NOTE: The specific uptake size index for quantifying radiopharmaceutical uptake

    NASA Astrophysics Data System (ADS)

    Fleming, John S.; Bolt, Livia; Stratford, Jennifer S.; Kemp, Paul M.

    2004-07-01

    Quantitative indices of radionuclide uptake in an object of interest provide a useful adjunct to qualitative interpretation in the diagnostic application of radionuclide imaging. This note describes a new measure of total uptake of an organ, the specific uptake size index (SUSI). It can either be related in absolute terms to the total activity injected or to the specific activity in a reference region. As it depends on the total activity in the object, the value obtained will not depend on the resolution of the imaging process, as is the case with some other similar quantitative indices. This has been demonstrated in an experiment using simulated images. The application of the index to quantification of dopamine receptor SPECT imaging and parathyroid thyroid subtraction planar scintigraphy is described. The index is considered to be of potential value in reducing variation in quantitative assessment of uptake in objects with applications in all areas of radionuclide imaging.

  4. Comparison of different tracers for PIV measurements in EHD airflow

    NASA Astrophysics Data System (ADS)

    Hamdi, M.; Havet, M.; Rouaud, O.; Tarlet, D.

    2014-04-01

    In this study, a proposed method for selecting a tracer for particle imaging velocimetry (PIV) measurement in electrohydrodynamics flows was developed. To begin with, several published studies were identified that exploit different tracers, such as oil smoke, cigarette smoke and titanium dioxide (TiO2). An assortment of tracers was then selected based on comparisons with conventional dimensionless numbers; Stokes number ( St), Archimedes number ( Ar) and electrical mobility ratio ( M). Subsequently, an experimental study for testing tracers was developed, which enabled the velocity profile of an ionic wind generated by a needle/ring configuration to be measured. Air velocity measurements carried out with a Pitot tube, considered as the reference measurements, were compared to PIV measurements for each tracer. In addition, the current-voltage curves and the evolution of the current during seeding were measured. All the experimental results show that TiO2, SiO2 microballoons and incense smoke are the ideal tracers in the series of tracers investigated.

  5. Dispersion of a tracer in the deep Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Ledwell, James R.; He, Ruoying; Xue, Zuo; DiMarco, Steven F.; Spencer, Laura J.; Chapman, Piers

    2016-02-01

    A 25 km streak of CF3SF5 was released on an isopycnal surface approximately 1100 m deep, and 150 m above the bottom, along the continental slope of the northern Gulf of Mexico, to study stirring and mixing of a passive tracer. The location and depth of the release were near those of the deep hydrocarbon plume resulting from the 2010 Deepwater Horizon oil well rupture. The tracer was sampled between 5 and 12 days after release, and again 4 and 12 months after release. The tracer moved along the slope at first but gradually moved into the interior of the Gulf. Diapycnal spreading of the patch during the first 4 months was much faster than it was between 4 and 12 months, indicating that mixing was greatly enhanced over the slope. The rate of lateral homogenization of the tracer was much greater than observed in similar experiments in the open ocean, again possibly enhanced near the slope. Maximum concentrations found in the surveys had fallen by factors of 104, 107, and 108, at 1 week, 4 months, and 12 months, respectively, compared with those estimated for the initial tracer streak. A regional ocean model was used to simulate the tracer field and help interpret its dispersion and temporal evolution. Model-data comparisons show that the model simulation was able to replicate statistics of the observed tracer distribution that would be important in assessing the impact of oil releases in the middepth Gulf.

  6. Fractal continuum model for tracer transport in a porous medium.

    PubMed

    Herrera-Hernández, E C; Coronado, M; Hernández-Coronado, H

    2013-12-01

    A model based on the fractal continuum approach is proposed to describe tracer transport in fractal porous media. The original approach has been extended to treat tracer transport and to include systems with radial and uniform flow, which are cases of interest in geoscience. The models involve advection due to the fluid motion in the fractal continuum and dispersion whose mathematical expression is taken from percolation theory. The resulting advective-dispersive equations are numerically solved for continuous and for pulse tracer injection. The tracer profile and the tracer breakthrough curve are evaluated and analyzed in terms of the fractal parameters. It has been found in this work that anomalous transport frequently appears, and a condition on the fractal parameter values to predict when sub- or superdiffusion might be expected has been obtained. The fingerprints of fractality on the tracer breakthrough curve in the explored parameter window consist of an early tracer breakthrough and long tail curves for the spherical and uniform flow cases, and symmetric short tailed curves for the radial flow case.

  7. Endocrine abnormalities in anorexia nervosa.

    PubMed

    Lawson, Elizabeth A; Klibanski, Anne

    2008-07-01

    Anorexia nervosa (AN) is a psychiatric disease associated with notable medical complications and increased mortality. Endocrine abnormalities, including hypogonadotropic hypogonadism, hypercortisolemia, growth hormone resistance and sick euthyroid syndrome, mediate the clinical manifestations of this disease. Alterations in anorexigenic and orexigenic appetite-regulating pathways have also been described. Decreases in fat mass result in adipokine abnormalities. Although most of the endocrine changes that occur in AN represent physiologic adaptation to starvation, some persist after recovery and might contribute to susceptibility to AN recurrence. In this Review, we summarize key endocrine alterations in AN, with a particular focus on the profound bone loss that can occur in this disease. Although AN is increasingly prevalent among boys and men, the disorder predominantly affects girls and women who are, therefore, the focus of this Review.

  8. Eye abnormalities in Fryns syndrome.

    PubMed

    Pierson, Diane M; Taboada, Eugenio; Butler, Merlin G

    2004-03-15

    Fryns syndrome is a rare, generally lethal, autosomal recessive multiple congenital anomaly (MCA) syndrome first described in 1979. Patients with the syndrome present with the classical findings of cloudy cornea, brain malformations, diaphragmatic defects, and distal limb deformities. Over 70 patients have been reported revealing a wide variety of phenotypic features. Although initially considered a major feature of Fryns syndrome, cloudy cornea has been relegated as a minor diagnostic sign and not commonly reported in patients since the original description. However, eye findings per se are not uncommon. Abnormal eye findings occasionally reported in Fryns syndrome potentially result in amblyopia and blindness, profoundly affecting neurologic outcome of those who survive the neonatal period. We reviewed 77 reported patients with Fryns syndrome and summarized the abnormal eye findings identified in 12 of the reported cases. In addition, we contribute three new patients with Fryns syndrome, one of which demonstrated unilateral microphthalmia and cloudy cornea.

  9. [Chromosome abnormalities in human cancer].

    PubMed

    Salamanca-Gómez, F

    1995-01-01

    Recent investigation on the presence of chromosome abnormalities in neoplasias has allowed outstanding advances in the knowledge of malignant transformation mechanisms and important applications in the clinical diagnosis and prognosis of leukaemias, lymphomas and solid tumors. The purpose of the present paper is to discuss the most relevant cytogenetic aberrations, some of them described at the Unidad de Investigación Médica en Genética Humana, Instituto Mexicano del Seguro Social, and to correlate these abnormalities with recent achievements in the knowledge of oncogenes, suppressor genes or antioncogenes, their chromosome localization, and their mutations in human neoplasia; as well as their perspectives in prevention and treatment of cancer that such findings permit to anticipate.

  10. Neuroendocrine abnormalities in Parkinson's disease.

    PubMed

    De Pablo-Fernández, Eduardo; Breen, David P; Bouloux, Pierre M; Barker, Roger A; Foltynie, Thomas; Warner, Thomas T

    2017-02-01

    Neuroendocrine abnormalities are common in Parkinson's disease (PD) and include disruption of melatonin secretion, disturbances of glucose, insulin resistance and bone metabolism, and body weight changes. They have been associated with multiple non-motor symptoms in PD and have important clinical consequences, including therapeutics. Some of the underlying mechanisms have been implicated in the pathogenesis of PD and represent promising targets for the development of disease biomarkers and neuroprotective therapies. In this systems-based review, we describe clinically relevant neuroendocrine abnormalities in Parkinson's disease to highlight their role in overall phenotype. We discuss pathophysiological mechanisms, clinical implications, and pharmacological and non-pharmacological interventions based on the current evidence. We also review recent advances in the field, focusing on the potential targets for development of neuroprotective drugs in Parkinson's disease and suggest future areas for research.

  11. Congenital abnormalities of the goat.

    PubMed

    Basrur, P K

    1993-03-01

    Congenital abnormalities of genetic and environmental causes constitute a striking proportion of the afflictions seen in goats. These include a variety of malformations and metabolic diseases that could occur in all breeds but tend to exhibit predisposition in some breeds of goats. Genetic abnormalities for which the carrier state is detectable with the aid of enzymes and surface protein markers can be eliminated from goat populations, whereas common polygenic disorders including udder problems in does and gynecomastia in bucks are more difficult to eradicate because the mutant genes responsible for these traits generally do not declare themselves until inbreeding brings together a critical concentration of liability genes to create a crisis. A substantial reduction of common abnormalities in this species, such as intersexuality in dairy breeds, abortion in Angora breed, and arthritis in the Pygmy breed, will require a change in breeders' preference and selection practice. In making these changes, however, the beneficial traits will have to be balanced against the undesirable effects of the selected mutant genes (pleiotropy), which hold the key to success or failure of a breed under domestication.

  12. Meiotic abnormalities in infertile males.

    PubMed

    Egozcue, J; Sarrate, Z; Codina-Pascual, M; Egozcue, S; Oliver-Bonet, M; Blanco, J; Navarro, J; Benet, J; Vidal, F

    2005-01-01

    Meiotic anomalies, as reviewed here, are synaptic chromosome abnormalities, limited to germ cells that cannot be detected through the study of the karyotype. Although the importance of synaptic errors has been underestimated for many years, their presence is related to many cases of human male infertility. Synaptic anomalies can be studied by immunostaining of synaptonemal complexes (SCs), but in this case their frequency is probably underestimated due to the phenomenon of synaptic adjustment. They can also be studied in classic meiotic preparations, which, from a clinical point of view, is still the best approach, especially if multiplex fluorescence in situ hybridization is at hand to solve difficult cases. Sperm chromosome FISH studies also provide indirect evidence of their presence. Synaptic anomalies can affect the rate of recombination of all bivalents, produce achiasmate small univalents, partially achiasmate medium-sized or large bivalents, or affect all bivalents in the cell. The frequency is variable, interindividually and intraindividually. The baseline incidence of synaptic anomalies is 6-8%, which may be increased to 17.6% in males with a severe oligozoospermia, and to 27% in normozoospermic males with one or more previous IVF failures. The clinical consequences are the production of abnormal spermatozoa that will produce a higher number of chromosomally abnormal embryos. The indications for a meiotic study in testicular biopsy are provided.

  13. Hepatic and extrahepatic uptake of HDL-derived plasma cholesterol in exercised and sedentary rats

    SciTech Connect

    Padmanathan, S.; Green, M.H.; Kris-Etherton, P.M.

    1986-03-01

    The present investigation was designed to study high density lipoprotein (HDL)-derived plasma cholesterol (C) turnover in hepatic and extrahepatic tissues of sedentary (S) and exercised (E) rats. 4-week-old Long Evans rats were exercised for 1 hr, 6 days weekly, for a period of 38 weeks, on a motor-driven treadmill at 0.8 mph at a 12% grade. Animals were injected with HDL that was labelled in vitro with /sup 3/H-cholesteryl ester. Serial blood samples and tissues were collected. HDL-C concentration was lower in E vs S rats (23.0 +/- 1.2 and 26.6 +/- 1.9 mg/dl, p < 0.01). While total plasma C was not different, liver C was higher in S vs E rats (8.2 +/- 0.8 and 7.2 +/- 0.5 mg/g). Adrenal C was higher in E vs S rats (29.5 +/- 2.3 and 20.7 +/- 2.3 mg/g, p < 0.01). Multicompartmental analysis of plasma and tissue tracer response led to development of an 8-component model (5 physiological; 3 nonphysiological) that depicted HDL-derived plasma C turnover. Plasma fraction of tracer declined more rapidly in E vs S rats. E rats cleared nonphysiological tracer more rapidly than S rats, but delayed release of tracer into the plasma longer. Fractional rate of tracer uptake into adrenals, liver, testes, and carcass was greater in E rats. There was a greater fractional turnover rate of tracer in adrenals and liver in S vs E rats. Hence HDL-derived plasma C turnover is altered with vigorous exercise.

  14. Some design considerations for the proposed Dixie Valley tracer test

    SciTech Connect

    Doughty, C.; Bodvarsson, G.S.

    1988-06-01

    A tracer test for the Dixie Valley, Nevada, geothermal resource is planned for the summer of 1988, in order to study the fluid flow paths that will develop under typical operating conditions. During the test six production wells will provide the power plant with steam sufficient for generation of 60 MWe, requiring fluid production at a rate of approximately 600 kg/sec. Up to 75% by mass of the extracted fluid will be reinjected into the reservoir, using four injection wells. Tracer will be added to the injected fluid for a twenty-minute period, and subsequently the produced fluid will be monitored for the tracer. 5 refs., 9 figs., 5 tabs.

  15. Tracer transport by the diabatic circulation deduced from satellite observations

    NASA Technical Reports Server (NTRS)

    Solomon, S.; Kiehl, J. T.; Garcia, R. R.; Grose, W.

    1986-01-01

    Nimbus-7 sensor data were used to track the diabatic circulation in the stratosphere to study the advective transport of CH4 and N2O as tracer species. Advective transport by the mean circulation was found to be a function of the temperature field and associated deviations from radiative equilibrium. A photochemical model was applied to account for the disappearance of the tracer species from the stratosphere. Comparisons between the SAMS data and modeling on the basis of the chemical loss rates of the tracers and the LIMS circulation data showed that the model predictions underestimated the resident abundances, although the global distributions and circulations exhibited a good match.

  16. Post-Surgical Atypical FDG-PET Uptake

    PubMed Central

    Dubroff, Jacob G.; Alavi, Abass; Friedberg, Joseph S.; Cengel, Keith A.

    2011-01-01

    False positive recognition is crucial for proper interpretation of FDG-PET studies. The authors present a case of a woman who underwent surgery over a month prior to PET/CT imaging which revealed significant tracer uptake within muscles and soft tissue in several sites contralateral to the location of surgery. The FDG-PET images of this case illustrate the importance of communication between physicians ordering and physicians reading FDG-PET/CT scans as well as atypical FDG-PET findings that could be interpreted as concerning but are, in fact, innocuous. This study also demonstrates the unusual glucose metabolic patterns which may arise following treatment be it surgical, chemotherapeutic or radiation. PMID:19851183

  17. A bioanalytical assay to distinguish cellular uptake routes for liposomes.

    PubMed

    Braun, Tobias; Kleusch, Christian; Naumovska, Elena; Merkel, Rudolf; Csiszár, Agnes

    2016-03-01

    Lipid-based nanoparticles are frequently used for drug or DNA delivery into mammalian cells. However it is difficult to determine whether such particles are taken up via endocytosis or fusion to the plasma membrane. Here, we propose a simple and reliable analytical method to do so based on the unique spectral properties of the fluorescent tracer BODIPY FL. At high local concentrations, this dye displays an additional red-shifted emission peak that is absent at low concentrations. In dye-loaded liposomes taken up by endocytosis, the local dye concentration did not significantly change upon internalization. Accordingly, unchanged fluorescence spectra were detected. When cells were incubated with liposomes able to fuse with the plasma membrane of mammalian cells, a reduction of local dye concentration and much weaker emission in the red-shifted peak were observed. The ratio of intensities in both fluorescence channels was shown to be a reliable indicator of the cellular uptake mechanism.

  18. Neonatal Respiratory Diseases in the Newborn Infant: Novel Insights from Stable Isotope Tracer Studies.

    PubMed

    Carnielli, Virgilio P; Giorgetti, Chiara; Simonato, Manuela; Vedovelli, Luca; Cogo, Paola

    2016-01-01

    Respiratory distress syndrome is a common problem in preterm infants and the etiology is multifactorial. Lung underdevelopment, lung hypoplasia, abnormal lung water metabolism, inflammation, and pulmonary surfactant deficiency or disfunction play a variable role in the pathogenesis of respiratory distress syndrome. High-quality exogenous surfactant replacement studies and studies on surfactant metabolism are available; however, the contribution of surfactant deficiency, alteration or dysfunction in selected neonatal lung conditions is not fully understood. In this article, we describe a series of studies made by applying stable isotope tracers to the study of surfactant metabolism and lung water. In a first set of studies, which we call 'endogenous studies', using stable isotope-labelled intravenous surfactant precursors, we showed the feasibility of measuring surfactant synthesis and kinetics in infants using several metabolic precursors including plasma glucose, plasma fatty acids and body water. In a second set of studies, named 'exogenous studies', using stable isotope-labelled phosphatidylcholine tracer given endotracheally, we could estimate surfactant disaturated phosphatidylcholine pool size and half-life. Very recent studies are focusing on lung water and on the endogenous biosynthesis of the surfactant-specific proteins. Information obtained from these studies in infants will help to better tailor exogenous surfactant treatment in neonatal lung diseases.

  19. Glucose uptake during contraction in isolated skeletal muscles from neuronal nitric oxide synthase μ knockout mice.

    PubMed

    Hong, Yet Hoi; Frugier, Tony; Zhang, Xinmei; Murphy, Robyn M; Lynch, Gordon S; Betik, Andrew C; Rattigan, Stephen; McConell, Glenn K

    2015-05-01

    Inhibition of nitric oxide synthase (NOS) significantly attenuates the increase in skeletal muscle glucose uptake during contraction/exercise, and a greater attenuation is observed in individuals with Type 2 diabetes compared with healthy individuals. Therefore, NO appears to play an important role in mediating muscle glucose uptake during contraction. In this study, we investigated the involvement of neuronal NOSμ (nNOSμ), the main NOS isoform activated during contraction, on skeletal muscle glucose uptake during ex vivo contraction. Extensor digitorum longus muscles were isolated from nNOSμ(-/-) and nNOSμ(+/+) mice. Muscles were contracted ex vivo in a temperature-controlled (30°C) organ bath with or without the presence of the NOS inhibitor N(G)-monomethyl-l-arginine (L-NMMA) and the NOS substrate L-arginine. Glucose uptake was determined by radioactive tracers. Skeletal muscle glucose uptake increased approximately fourfold during contraction in muscles from both nNOSμ(-/-) and nNOSμ(+/+) mice. L-NMMA significantly attenuated the increase in muscle glucose uptake during contraction in both genotypes. This attenuation was reversed by L-arginine, suggesting that L-NMMA attenuated the increase in muscle glucose uptake during contraction by inhibiting NOS and not via a nonspecific effect of the inhibitor. Low levels of NOS activity (~4%) were detected in muscles from nNOSμ(-/-) mice, and there was no evidence of compensation from other NOS isoform or AMP-activated protein kinase which is also involved in mediating muscle glucose uptake during contraction. These results indicate that NO regulates skeletal muscle glucose uptake during ex vivo contraction independently of nNOSμ.

  20. Selective 2-( sup 18 F)fluorodopa uptake for melanogenesis in murine metastatic melanomas

    SciTech Connect

    Ishiwata, K.; Kubota, K.; Kubota, R.; Iwata, R.; Takahashi, T.; Ido, T. )

    1991-01-01

    The relationship between 3,4-dihydroxy-2-({sup 18}F)fluoro-L-phenylalanine (2-({sup 18}F)FDOPA) uptake and melanogenesis was studied using mice bearing two B16 melanomas: B16-F1 has a higher melanin synthesis ability and a slower growing rate than the higher metastatic B16-F10. A significantly higher 2-({sup 18}F)FDOPA uptake by B16-F1 than by B16-F10 and a reverse relationship for the uptake of ({sup 14}C) 2-deoxy-2-fluoro-D-glucose and ({sup 3}H)thymidine were observed 1 hr postinjection. F1-to-F10 ratios of both the 2-({sup 18}F)FDOPA uptake and the acid-insoluble radioactivity increased to about 5 at 6 hr, which paralleled the melanin content. FM3A mammary carcinoma showed a 2-({sup 18}F)FDOPA uptake similar to the B16-F10 but without the acid-insoluble radioactivity. With D,L-DOPA loading, a 55% decreased uptake by FM3A 1 hr postinjection was significantly greater than the 20% reduction in both melanomas. O-Methylated 2-({sup 18}F)FDOPA was a predominant acid-soluble metabolite in all tumors. Whole-body autoradiography discriminated the two melanomas clearly. 2-({sup 18}F)FDOPA may be a promising tracer for the selective imaging of melanogenesis.

  1. Tracer study of San Vicente reservoir

    SciTech Connect

    Williams, R.T.

    1996-11-01

    The City of San Diego remains on the cutting edge of water conservation. With an unwavering commitment to maintain an adequate water supply for the future, water repurification is now being considered. The City of San Diego and San Diego Water Authority (CWA) have proposed to recycle repurified water through San Vicente Reservoir. A key component of assessing the feasibility of such a project is to calculate the retention time of repurified water in the reservoir. Working with engineering consultant team (Montgomery-Watson Engineers and Flow Science, Incorporated) two tracer studies were conducted to model the circulation and mixing of repurified water introduced into the reservoir. The goal was to determine whether repurified water recycled through San Vicente will meet the retention time criteria established by the Department of Health Services. This presentation however, will not attempt to interpret the results of the study, that aspect will be evaluated by the Flow Scientist. The objective here is to explain how the project was carried out and to focus mostly on the analytical work performed on the samples by the chemist in the City of San Diego Water Quality Laboratory.

  2. Cumulus cloud transport of transient tracers

    NASA Technical Reports Server (NTRS)

    Gidel, L. T.

    1983-01-01

    A theoretical framework is developed for including cumulus cloud transport, rainout of water soluble gases, and aqueous phase chemistry into gas phase photochemical models. Cloud populations are represented as ensemble distributions of individual clouds of various heights. An individual cloud is represented as a one-dimensional, steady state plume with height-independent radius entraining air from the boundary of the cloud. The model is applied to several hypothetical atmospheric tracers to show how clouds may affect the tropospheric distributions of ozone, NO(y), SO2, peroxyacetylnitrate, hydrocarbons, and other gases. Although the numerical experiments were based on cloud mass fluxes from diagnostic studies in the tropics and thus are not representative of the entire globe, it was found that an increasing mixing ratio with height in the free troposphere can be produced for some gases with only a surface source when clouds are present. This suggests that some reactive tropospheric species with primarily surface sources may play a somewhat more important role in tropospheric chemistry than is presently believed depending on the global distribution of cloud mass fluxes. Deficiencies in existing photochemical models due to the way clouds are typically treated are discussed.

  3. National Biomedical Tracer Facility: Project definition study

    SciTech Connect

    Heaton, R.; Peterson, E.; Smith, P.

    1995-05-31

    The Los Alamos National Laboratory is an ideal institution and New Mexico is an ideal location for siting the National Biomedical Tracer Facility (NBTF). The essence of the Los Alamos proposal is the development of two complementary irradiation facilities that combined with our existing radiochemical processing hot cell facilities and waste handling and disposal facilities provide a low cost alternative to other proposals that seek to satisfy the objectives of the NBTF. We propose the construction of a 30 MeV cyclotron facility at the site of the radiochemical facilities, and the construction of a 100 MeV target station at LAMPF to satisfy the requirements and objectives of the NBTF. We do not require any modifications to our existing radiochemical processing hot cell facilities or our waste treatment and disposal facilities to accomplish the objectives of the NBTF. The total capital cost for the facility defined by the project definition study is $15.2 M. This cost estimate includes $9.9 M for the cyclotron and associated facility, $2.0 M for the 100 MeV target station at LAMPF, and $3.3 M for design.

  4. Neuroblastoma: MIBG Imaging and New Tracers.

    PubMed

    Pfluger, Thomas; Piccardo, Arnoldo

    2017-03-01

    Neuroblastoma is an embryonic tumor of the peripheral sympathetic nervous system, and is metastatic or otherwise high risk for relapse in nearly 50% of cases, with a long-term survival of <40%. Therefore, exact staging with radiological and nuclear medicine imaging methods is crucial for finding the adequate therapeutic choice. The tumor cells express the norepinephrine transporter, which makes metaiodobenzylguanidine (MIBG), an analogue of norepinephrine, an ideal tumor-specific agent for imaging. On the contrary, MIBG imaging has several disadvantages such as limited spatial resolution, limited sensitivity in small lesions, need for two or even more acquisition sessions, and a delay between the start of the examination and result. Most of these limitations can be overcome with positron emission tomography (PET) using different radiotracers. Furthermore, for operative or biopsy planning, a combination with morphological imaging methods is indispensable. This article would discuss the therapeutic strategy for primary and follow-up diagnosis in neuroblastoma using MIBG scintigraphy and different new PET tracers as well as multimodality imaging.

  5. Carbonyl sulfide (COS) as a tracer to constrain surface carbon fluxes

    NASA Astrophysics Data System (ADS)

    Yakir, Dan; Berkelhammer, Max; Miller, John; Montzka, Steve; Chen, Huilin

    2014-05-01

    The potential use of COS as tracer of CO2 flux into leaves associated gross primary productivity (GPP), and separately from CO2 flux associated with ecosystem respiration (Re), stimulate research on COS-CO2 interactions during biosphere-atmosphere gas exchange. This is based on the observation that COS co-diffuse with CO2 into vegetation, but without an emission outflux. Recent advances in laser spectroscopy and the availability of high precision field deployable quantum cascade laser systems resulted in accumulation of new results from laboratory-scale control experiments, field studies, atmospheric measurements and, in turn, large scale modeling. These studies demonstrate the potential in the COS application to carbon cycle research, but also highlight key uncertainties, such as associated with soil uptake of COS. Soil uptake is based on dissolution and hydrolysis in soil moisture, which can be enhanced by carbonic anhydrase (CA) that can exist in soil and litter and microorganisms. Our recent in-situ measurements over the diurnal cycle and across a range of ecosystems and tree species supported the idea of a robust COS to CO2 uptake ratio of near 1.6, and indicated that soils act mostly as a relatively small COS sink, equivalent to 2-6% of canopy uptake during peak activity period. The results also indicated that small soil net COS emission can be observed under certain conditions. The importance of CA activities has been demonstrated in soils in CO2 studies using stable isotopes (18O), and for COS in leaves using anti-sense lines, but quantifying its importance for soil COS uptake is still lacking. Measurements in canopy air showed that the daily co-variation between COS and CO2 reflects the interplay among the effects of soil, leaf and atmospheric boundary layer dynamics. Further extending observations to background tropospheric measurements of the seasonal drawdown in CO2 and in COS demonstrates that comparing the drawdowns of COS, CO2 and its 13C, could

  6. Visual pathway abnormalities in tuberculous meningitis.

    PubMed

    Maurya, Pradeep Kumar; Singh, Ajai Kumar; Sharma, Lalit; Kulshreshtha, Dinkar; Thacker, Anup Kumar

    2016-11-01

    Ophthalmological complications are common and disabling in patients with tuberculous meningitis. We aimed to study the visual pathway abnormalities in patients with tuberculous meningitis. Forty-three patients with tuberculous meningitis were subjected to visual evoked responses (VER) and neuroophthalmologic assessment. Neuroophthalmologic assessment revealed abnormalities in 22 (51.3%) patients. VER were found to be abnormal in 27 (62.8%) patients. The VER abnormalities included prolonged P100 latencies with relatively normal amplitude and significant interocular latency differences. Visual pathways abnormalities are common in patients with tuberculous meningitis and are often subclinical. Pathophysiologic explanations for electrophysiological abnormalities on VER in these patients are incompletely understood and needs further exploration.

  7. Manganese uptake of imprinted polymers

    SciTech Connect

    Susanna Ventura

    2015-09-30

    Batch tests of manganese imprinted polymers of variable composition to assess their ability to extract lithium and manganese from synthetic brines at T=45C . Data on manganese uptake for two consecutive cycles are included.

  8. 6-( sup 18 F)fluoro-L-fucose: A possible tracer for assessing glycoconjugate synthesis in tumors with positron emission tomography

    SciTech Connect

    Ishiwata, K.; Tomura, M.; Ido, T.; Iwata, R.; Sato, K.; Hatazawa, J.; Kameyama, M.; Imahori, Y. )

    1990-12-01

    The potential of 6-({sup 18}F)fluoro-L-fucose (6-({sup 18}F)FFuc) for assessing glycoconjugate synthesis in tumors with positron emission tomography (PET) was investigated. Using the tissue sampling method with five tumor models, different time-radioactivity profiles were found: a nearly constant level in Lewis lung carcinoma (3LL) and different clearance patterns in others. Rapid clearance in normal tissues resulted in preferable uptake ratios for tumor imaging of brain and pancreas. Metabolic studies and the L-fucose loading effects on the tissue uptake proved the tracer to be a biochemically active L-fucose analog. Imaging of the intracranial rat glioma and 3LL in lungs or hepatomas in mice by autoradiography (ARG) and intramuscular VX-2 carcinoma in rabbits by PET was demonstrated. Using double-radionuclide ARG, similar distribution images of 6-({sup 18}F)FFuc and {sup 14}C-L-fucose but different tumor-to-liver uptake ratios were found. A metastasis model seemed to show a higher uptake of both tracers as compared to a primary tumor model.

  9. PSMA Uptake in Mediastinal Sarcoidosis.

    PubMed

    Ardies, Philip Junior; Gykiere, Pieterjan; Goethals, Lode; De Mey, Johan; De Geeter, Frank; Everaert, Hendrik

    2017-04-01

    Prostate-specific membrane antigen (PSMA) is a cell surface glycoprotein which is frequently overexpressed on prostate cancer cells. Ga-PSMA PET/CT plays an increasing role in prostate cancer management. However, growing evidence suggests increased PSMA uptake in a variety of other malignant tumor entities and in some benign lesions. This report describes PSMA uptake in numerous thoracic lymph nodes in a patient with known mediastinal sarcoidosis. Knowledge and recognition of these possibilities are important to avoid scan misinterpretation.

  10. An Analysis of Whole Body Tracer Kinetics in Dynamic PET Studies With Application to Image-Based Blood Input Function Extraction

    PubMed Central

    Huang, Jian; O’Sullivan, Finbarr

    2014-01-01

    In a positron emission tomography (PET) study, the local uptake of the tracer is dependent on vascular delivery and retention. For dynamic studies the measured uptake time-course information can be best interpreted when knowledge of the time-course of tracer in the blood is available. This is certainly true for the most established tracers such as 18F-Fluorodeoxyglucose (FDG) and 15O-Water (H2O). Since direct sampling of blood as part of PET studies is increasingly impractical, there is ongoing interest in image-extraction of blood time-course information. But analysis of PET-measured blood pool signals is complicated because they will typically involve a combination of arterial, venous and tissue information. Thus, a careful appreciation of these components is needed to interpret the available data. To facilitate this process, we propose a novel Markov chain model for representation of the circulation of a tracer atom in the body. The model represents both arterial and venous time-course patterns. Under reasonable conditions equilibration of tracer activity in arterial and venous blood is achieved by the end of the PET study—consistent with empirical measurement. Statistical inference for Markov model parameters is a challenge. A penalized nonlinear least squares process, incorporating a generalized cross-validation score, is proposed. Random effects analysis is used to adaptively specify the structure of the penalty function based on historical samples of directly measured blood data. A collection of arterially sampled data from PET studies with FDG and H2O is used to illustrate the methodology. These data analyses are highly supportive of the overall modeling approach. An adaptation of the model to the problem of extraction of arterial blood signals from imaging data is also developed and promising preliminary results for cerebral and thoracic imaging studies with FDG and H2O are obtained. PMID:24770914

  11. Isotope Tracers To Study the Environmental Fate and Bioaccumulation of Metal-Containing Engineered Nanoparticles: Techniques and Applications.

    PubMed

    Yin, Yongguang; Tan, Zhiqiang; Hu, Ligang; Yu, Sujuan; Liu, Jingfu; Jiang, Guibin

    2017-03-08

    The rapidly growing applicability of metal-containing engineered nanoparticles (MENPs) has made their environmental fate, biouptake, and transformation important research topics. However, considering the relatively low concentration of MENPs and the high concentration of background metals in the environment and in organisms, tracking the fate of MENPs in environment-related scenarios remains a challenge. Intrinsic labeling of MENPs with radioactive or stable isotopes is a useful tool for the highly sensitive and selective detection of MENPs in the environment and organisms, thus enabling tracing of their transformation, uptake, distribution, and clearance. In this review, we focus on radioactive/stable isotope labeling of MENPs for their environmental and biological tracing. We summarize the advantages of intrinsic radioactive/stable isotopes for MENP labeling and discuss the considerations in labeling isotope selection and preparation of labeled MENPs, as well as exposure routes and detection of labeled MENPs. In addition, current practice in the use of radioactive/stable isotope labeling of MENPs to study their environmental fate and bioaccumulation is reviewed. Future perspectives and potential applications are also discussed, including imaging techniques for radioactive- and stable-isotope-labeled MENPs, hyphenated multistable isotope tracers with speciation analysis, and isotope fractionation as a MENP tracer. It is expected that this critical review could provide the necessary background information to further advance the applications of isotope tracers to study the environmental fate and bioaccumulation of MENPs.

  12. A Systematic Method For Tracer Test Analysis: An Example Using Beowawe Tracer Data

    SciTech Connect

    G. Michael Shook

    2005-01-01

    Quantitative analysis of tracer data using moment analysis requires a strict adherence to a set of rules which include data normalization, correction for thermal decay, deconvolution, extrapolation, and integration. If done correctly, the method yields specific information on swept pore volume, flow geometry and fluid velocity, and an understanding of the nature of reservoir boundaries. All calculations required for the interpretation can be done in a spreadsheet. The steps required for moment analysis are reviewed in this paper. Data taken from the literature is used in an example calculation.

  13. Whole Hillslope Irrigation Reveals Differential Interflow Behavior of Dye Tracers, Conservative Solutes and Nutrients

    NASA Astrophysics Data System (ADS)

    Jackson, C. R.; Du, E.; Klaus, J.; Griffiths, N. A.; McDonnell, J. J.; Blake, J. I.

    2012-12-01

    Previous investigations of perching and interflow behavior in low angle hillslopes in the SC Coastal Plain have suggested a high threshold for interflow occurrence. Here we report a new irrigation experiment designed to quantify interflow thresholds and reveal subsurface mixing processes during steady state flow conditions over a 12m x 16.5m plot draining to an interflow interception trench. Dye tracers were applied on surface transects prior to irrigation, and bromide (conservative tracer), nitrate, ammonium, and phosphorus (reactive tracers) were added at constant concentrations to the irrigation water drawn from a deep aquifer with a distinct isotopic signature. 417mm of water were applied over 51 hours, and drainage conditions were monitored for a week following irrigation. Interflow in the two drains commenced after 131 and 178mm, and flow rates diminished immediately after irrigation ceased, although interflow continued for four more days. Over the experiment, 199mm of water (49% of applied water) appeared as interflow. Dye tracers moved rapidly with the wetting front, with peak concentrations measured shortly after flow commencement, suggesting saturated topsoil conductivities of 0.5 to 1.5 m/hr. No preferential flow was observed during this experiment or previously during rainfall events at the trench face. Bromide concentrations and the new water fraction rose steadily throughout irrigation, peaking about 16 hours after irrigation ceased. Ammonium and phosphorus concentrations at the trench face were low, suggesting rapid uptake or sorption, while nitrate concentrations were higher, suggesting more conservative transport. Our two collection drains showed identical temporal variation in bromide concentrations but consistently different new/old water fractions, indicating differences in flow paths and storages within the plot. These data suggest that tightly bound soil water exchanged with new water throughout the experiment, and that a significant portion

  14. Tracking thermal fronts with temperature-sensitive, chemically reactive tracers

    SciTech Connect

    Robinson, B.A.; Birdsell, S.A.

    1987-01-01

    Los Alamos is developing tracer techniques using reactive chemicals to track thermal fronts in fractured geothermal reservoirs. If a nonadsorbing tracer flowing from the injection to production well chemically reacts, its reaction rate will be a strong function of temperature. Thus the extent of chemical reaction will be greatest early in the lifetime of the system, and less as the thermal front progresses from the injection to production well. Early laboratory experiments identified tracers with chemical kinetics suitable for reservoirs in the temperature range of 75 to 100/sup 0/C. Recent kinetics studies have focused on the kinetics of hydrolysis of derivatives of bromobenzene. This class of reactions can be used in reservoirs ranging in temperature from 150 to 275/sup 0/C, which is of greater interest to the geothermal industry. Future studies will include laboratory adsorption experiments to identify possibly unwanted adsorption on granite, development of sensitive analytical techniques, and a field demonstration of the reactive tracer concept.

  15. Ensemble Neuron Tracer for 3D Neuron Reconstruction.

    PubMed

    Wang, Ching-Wei; Lee, Yu-Ching; Pradana, Hilmil; Zhou, Zhi; Peng, Hanchuan

    2017-02-09

    Tracing of neuron paths is important in neuroscience. Recent studies have shown that it is possible to segment and reconstruct three-dimensional morphology of axons and dendrites using fully automatic neuron tracing methods. A specific tracer may be better than others for a specific dataset, but another tracer could perform better for some other datasets. Ensemble of learners is an effective way to improve learning accuracy in machine learning. We developed automatic ensemble neuron tracers, which consistently perform well on 57 datasets of 5 species collected from 7 laboratories worldwide. Quantitative evaluation based on the data generated by human annotators shows that the proposed ensemble tracers are valuable for 3D neuron tracing and can be widely applied to different datasets.

  16. Unraveling complex hydrogeologic systems using field tracer tests

    NASA Astrophysics Data System (ADS)

    Dam, William A.; Nicholson, Thomas

    Tracking the movement of underground contaminants is vital to protecting public health and the environment worldwide. Scientific efforts using field tracer techniques to solve contaminant migration problems are rapidly evolving to fill critical information gaps and provide confirmation of laboratory data and numerical models. Various chemical tracers are being used to formulate and evaluate alternative conceptual hydrogeologic modelssemi; namely, to constrain hydraulic properties of geologic systems, identify sources of groundwater, flow paths, and rates, and determine mechanisms that affect contaminant transport. Naturally occurring elements and environmental isotopes from atmospheric and underground nuclear testing can make excellent tracers. In addition, characterizing sites of future waste disposal, such as the potential high-level nuclear waste repository at Yucca Mountain, requires new and innovative techniques like injecting surrogate tracers that simulate potential contaminants and shed light on mechanisms that could control future contaminant migration.

  17. Microfluidics for synthesis of peptide-based PET tracers.

    PubMed

    Liu, Yang; Tian, Mei; Zhang, Hong

    2013-01-01

    Positron emission tomography (PET) is a powerful noninvasive tool for acquisition of the physiological parameters in human and animals with the help of PET tracers. Among all the PET tracers, radiolabeled peptides have been widely explored for cancer-related receptor imaging due to their high affinity and specificity to receptors. But radiochemistry procedures for production of peptide-based PET tracers are usually complex, which makes large-scale clinical studies relatively challenging. New radiolabeling technologies which could simplify synthesis and purification procedures, are extremely needed. Over the last decade, microfluidics and lab-on-a-chip (LOC) technology have boomed as powerful tools in the field of organic chemistry, which potentially provide significant help to the PET chemistry. In this minireview, microfluidic radiolabeling technology is described and its application for synthesis of peptide-based PET tracers is summarized and discussed.

  18. Fundamentals of tracer kinetics for dynamic contrast-enhanced MRI.

    PubMed

    Koh, Tong San; Bisdas, Sotirios; Koh, Dow Mu; Thng, Choon Hua

    2011-12-01

    Tracer kinetic methods employed for quantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) share common roots with earlier tracer studies involving arterial-venous sampling and other dynamic imaging modalities. This article reviews the essential foundation concepts and principles in tracer kinetics that are relevant to DCE MRI, including the notions of impulse response and convolution, which are central to the analysis of DCE MRI data. We further examine the formulation and solutions of various compartmental models frequently used in the literature. Topics of recent interest in the processing of DCE MRI data, such as the account of water exchange and the use of reference tissue methods to obviate the measurement of an arterial input, are also discussed. Although the primary focus of this review is on the tracer models and methods for T(1) -weighted DCE MRI, some of these concepts and methods are also applicable for analysis of dynamic susceptibility contrast-enhanced MRI data.

  19. Comparison between kinetic modelling and graphical analysis for the quantification of [18F]fluoromethylcholine uptake in mice

    PubMed Central

    2013-01-01

    Background Until now, no kinetic model was described for the oncologic tracer [18F]fluoromethylcholine ([18F]FCho), so it was aimed to validate a proper model, which is easy to implement and allows tracer quantification in tissues. Methods Based on the metabolic profile, two types of compartmental models were evaluated. One is a 3C2i model, which contains three tissue compartments and two input functions and corrects for possible [18F]fluorobetaine ([18F]FBet) uptake by the tissues. On the other hand, a two-tissue-compartment model (2C1i) was evaluated. Moreover, a comparison, based on intra-observer variability, was made between kinetic modelling and graphical analysis. Results Determination of the [18F]FCho-to-[18F]FBet uptake ratios in tissues and evaluation of the fitting of both kinetic models indicated that corrections for [18F]FBet uptake are not mandatory. In addition, [18F]FCho uptake is well described by the 2C1i model and by graphical analysis by means of the Patlak plot. Conclusions The Patlak plot is a reliable, precise, and robust method to quantify [18F]FCho uptake independent of scan time or plasma clearance. In addition, it is easily implemented, even under non-equilibrium conditions and without creating additional errors. PMID:24034278

  20. Mobility of Metal Tracers in Unsaturated Tuffs of Busted Butte

    NASA Astrophysics Data System (ADS)

    Groffman, A. R.

    2001-12-01

    A complex tracer mixture was injected continuously for over two years into a 10 m x 10 m x 7 m block of unsaturated tuff as part of the Busted Butte unsaturated-zone tracer test at Yucca Mountain. The test was designed to measure tracer transport within the Topopah Springs and Calico Hills tuffs, units that occur between the potential high-level nuclear waste repository at Yucca Mountain and the water table below. The mixture included nonreactive (Br, I, and fluorinated benzoic acids (FBAs)) and reactive tracers (Li, Ce, Sm, Ni, Co, and Mn). Bromide, I, FBAs, and Li were detected during the test on absorbent pads emplaced in a series of solute collection boreholes located beneath the injectors but the more strongly sorbing metals did not reach the collection boreholes during this period. To determine the distribution and mobility of these metals, tracer constituents were extracted from tuff samples collected during overcoring and mineback of the test block. Tracers were extracted from the tuff samples by leaching with a 5% nitric acid solution for metals and a bicarbonate-carbonate buffer for anions. Results from the overcore sample suite show that metals have migrated through the tuff in the region adjacent to and immediately below the tracer injectors. Consistent with laboratory sorption measurements and observed breakthrough in the collection boreholes, rock analyses showed that Li is the most mobile of the metals. Co and Ni behave similarly, traveling tens of cm from the injection sites, while Sm and Ce moved far less, possibly due to precipitation reactions in addition to sorption. Determination of Mn transport is complicated by high background concentrations in the tuff; additional background samples are currently being evaluated. As expected, our rock analyses show that the nonreactive tracers Br and FBAs have moved beyond the overcore region, corroborating results from collection boreholes.

  1. Advanced Tracers in PET Imaging of Cardiovascular Disease

    PubMed Central

    Zhang, Wei; Wu, Hua; Liu, Gang

    2014-01-01

    Cardiovascular disease is the leading cause of death worldwide. Molecular imaging with targeted tracers by positron emission tomography (PET) allows for the noninvasive detection and characterization of biological changes at the molecular level, leading to earlier disease detection, objective monitoring of therapies, and better prognostication of cardiovascular diseases progression. Here we review, the current role of PET in cardiovascular disease, with emphasize on tracers developed for PET imaging of cardiovascular diseases. PMID:25389529

  2. Perspectives of transient tracer applications and limiting cases

    NASA Astrophysics Data System (ADS)

    Stöven, T.; Tanhua, T.; Hoppema, M.; Bullister, J. L.

    2015-09-01

    Currently available transient tracers have different application ranges that are defined by their temporal input (chronological transient tracers) or their decay rate (radioactive transient tracers). Transient tracers range from tracers for highly ventilated water masses such as sulfur hexafluoride (SF6) through tritium (3H) and chlorofluorocarbons (CFCs) up to tracers for less ventilated deep ocean basins such as argon-39 (39Ar) and radiocarbon (14C). In this context, highly ventilated water masses are defined as water masses that have been in contact with the atmosphere during the last decade. Transient tracers can be used to empirically constrain the transit time distribution (TTD), which can often be approximated with an inverse Gaussian (IG) distribution. The IG-TTD provides information about ventilation and the advective/diffusive characteristics of a water parcel. Here we provide an overview of commonly used transient tracer couples and the corresponding application range of the IG-TTD by using the new concept of validity areas. CFC-12, CFC-11 and SF6 data from three different cruises in the South Atlantic Ocean and Southern Ocean as well as 39Ar data from the 1980s and early 1990s in the eastern Atlantic Ocean and the Weddell Sea are used to demonstrate this method. We found that the IG-TTD can be constrained along the Greenwich Meridian south to 46° S, which corresponds to the Subantarctic Front (SAF) denoting the application limit. The Antarctic Intermediate Water (AAIW) describes the limiting water layer in the vertical. Conspicuous high or lower ratios between the advective and diffusive components describe the transition between the validity area and the application limit of the IG-TTD model rather than describing the physical properties of the water parcel. The combination of 39Ar and CFC data places constraints on the IG-TTD in the deep water north of the SAF, but not beyond this limit.

  3. Sand Tracer Movement Measured in a Strong Rip Current

    DTIC Science & Technology

    2010-01-01

    and colleagues performed a trial sand tracer experiment in a strong rip current on Ajigaura Beach, Japan , a sandy beach facing the Pacific Ocean...demonstrates that such measurements are possible. Introduction As part of a series of intensive field data collection studies in Japan (Horikawa and...the planned experiment area at Ajigaura Beach, Japan , facing the Pacific Ocean, and it was decided to perform a trial sand tracer experiment in the

  4. Relation between regional myocardial uptake of /sup 82/Rb and perfusion: absolute reduction of cation uptake in ischemia

    SciTech Connect

    Selwyn, A.P.; Allan, R.M.; L'Abbate, A.; Horlock, P.; Camici, P.; Clark, J.; O'Brien, H.A.; Grant, P.M.

    1982-07-01

    Experiments were undertaken using /sup 82/Rb and position tomography to examine the relation between myocardial perfusion and cation uptake during acute ischemia. /sup 82/Rb was repeatedly eluted from a /sup 82/Sr-/sup 82/Rb generator. In six dogs emission tomograms were used to measure the delivered arterial and myocardial concentrations at rest and after coronary stenosis, stress and ischemia. There was a poor overall relation between regional myocardial uptake and flow measured by microspheres and a large individual variability. Extraction of /sup 82/Rb was inversely related to flow. Significant regional reduction of cation uptake was detected in the tomograms when regional flow decreased by more than 35 percent. This reduction was significantly greater when ischemia was present. A small but significantly greater when ischemia was present. A small but significant decrease (33.0 +/- 9.1 percent, mean +/- standard deviation) in the myocardial uptake of /sup 82/Rb was detected only when flow was increased by more than 120 percent in relation to a control area after administration of dypiridamole. The technique using /sup 82/Rb and tomography was applied in five volunteers and five patients with angina pectoris and coronary artery disease. Myocardial tomograms recorded at rest and after exercise in the volunteers showed homogeneous uptake of cation in reproducible and repeatable scans. In contrast, the patients with coronary artery disease showed an absolute mean decrease of 36 +/- 14 percent in regional myocardial uptake of /sup 82/Rb after exercise. These abnormalities persisted in serial tomograms for more than 20 minutes after the symptoms and electrocardiographic signs of ischemia.

  5. Low-set ears and pinna abnormalities

    MedlinePlus

    Low-set ears; Microtia; "Lop" ear; Pinna abnormalities; Genetic defect-pinna; Congenital defect-pinna ... most cases, a health care provider finds pinna abnormalities during the first well-baby exam. This exam ...

  6. Abnormalities of the erythrocyte membrane.

    PubMed

    Gallagher, Patrick G

    2013-12-01

    Primary abnormalities of the erythrocyte membrane are characterized by clinical, laboratory, and genetic heterogeneity. Among this group, hereditary spherocytosis patients are more likely to experience symptomatic anemia. Treatment of hereditary spherocytosis with splenectomy is curative in most patients. Growing recognition of the long-term risks of splenectomy has led to re-evaluation of the role of splenectomy. Management guidelines acknowledge these considerations and recommend discussion between health care providers, patient, and family. The hereditary elliptocytosis syndromes are the most common primary disorders of erythrocyte membrane proteins. However, most elliptocytosis patients are asymptomatic and do not require therapy.

  7. Foot abnormalities of wild birds

    USGS Publications Warehouse

    Herman, C.M.; Locke, L.N.; Clark, G.M.

    1962-01-01

    The various foot abnormalities that occur in birds, including pox, scaly-leg, bumble-foot, ergotism and freezing are reviewed. In addition, our findings at the Patuxent Wildlife Research Center include pox from dove, mockingbird, cowbird, grackle and several species of sparrows. Scaly-leg has been particularly prevalent on icterids. Bumble foot has been observed in a whistling swan and in a group of captive woodcock. Ergotism is reported from a series of captive Canada geese from North Dakota. Several drug treatments recommended by others are presented.

  8. Natural iodine-129 as an environmental tracer

    NASA Astrophysics Data System (ADS)

    Fabryka-Martin, J.; Bentley, H.; Elmore, D.; Airey, P. L.

    1985-02-01

    Iodine-129 ( t 1/2, 16 My) is a naturally-occurring tracer which can be used to study hydrologic and geologic processes on time scales up to 100 My. The pre-bomb atmospheric ratio 129I /I should have been constant in time and space and is the starting value in ground-water recharge. Subsequent ratio changes in ground water should be determined by isotope contributions from three sources: recharge water, iodine leached from the formation, and in situ uranium fission. The mathematical expression of these time-dependent processes forms the basis for dating and tracing applications. The expected behavior of natural 129I in ground water is compared to results from field studies. Ground-water samples from the Great Artesian Basin, Australia, provide an estimate of the atmospheric equilibrium ratio, 6 × 10 -13. Down-gradient changes in water up to 1 My old suggest that subsurface production can be significant. The usefulness of 129I as an indicator of brine source and age is verified in brines collected in and around Louisiana salt domes. The method leads to ages of 7 and 9 My for two brine pockets trapped within Jurassic salt, and 32 to >40 My for oil-field brines in Miocene sands adjacent to the domes. The results demonstrate the capability of tandem accelerator mass spectrometry to measure as few as 10 7 atoms of 129I in 10 mg I with 10% precision. Although such atom sensitivity can be achieved otherwise, the accelerator technique is necessary to measure naturally low pre-1945 cosmogenic isotope ratios.

  9. Cross-shore surfzone tracer dispersion in an alongshore current

    NASA Astrophysics Data System (ADS)

    Clark, David B.; Feddersen, Falk; Guza, R. T.

    2010-10-01

    Cross-shore surfzone tracer dispersion in a wave driven alongshore current is examined over a range of wave and current conditions with 6 continuous dye releases, each roughly 1-2 hours in duration, at Huntington Beach, California. Fluorescent dye tracer released near the shoreline formed shore parallel plumes that were sampled on repeated cross-shore transects with a jet ski mounted fluorometer. Ensemble averaged cross-shore tracer concentration profiles are generally shoreline attached (maximum at or near the shoreline), with increasing cross-shore widths and decreasing peak values with downstream distance. More than a few 100 m from the source, tracer is often well mixed across the surfzone (i.e., saturated) with decreasing tracer concentrations farther seaward. For each release, cross-shore surfzone absolute diffusivities are estimated using a simple Fickian diffusion solution with a no-flux boundary at the shoreline, and range from 0.5-2.5 m2 s-1. Surfzone diffusivity scalings based on cross-shore bore dispersion, surfzone eddy mixing length, and undertow driven shear dispersion are examined. The mixing-length scaling has correlation r2 = 0.59 and the expected best-fit slope <1, indicating that horizontal rotational motions are important for cross-shore tracer dispersion in the surfzone.

  10. Determination of stream reaeration coefficients by use of tracers

    USGS Publications Warehouse

    Kilpatrick, F.A.; Rathbun, R.E.; Yotsukura, Nobuhiro; Parker, G.W.; DeLong, L.L.

    1989-01-01

    Stream reaeration is the physical absorption of oxygen from the atmosphere by a flowing stream. This is the primary process by which a stream replenishes the oxygen consumed in the biodegradation of organic wastes. Prior to 1965, reaeration rate coefficients could be estimated only by indirect methods. In 1965, a direct method of measuring stream reaeration coefficients was developed whereby a radioactive tracer gas was injected into a stream-the principle being that the tracer gas would be desorbed from the stream inversely to how oxygen would be absorbed. The technique has since been modified by substituting hydrocarbon gases for the radioactive tracer gas. This manual describes the slug-injection and constant-rate-injection methods of measuring gas-tracer desorption. Emphasis is on the use of rhodamine WT dye as a relatively conservative tracer and propane as the nonconservative gas tracer, on planning field tests, on methods of injection, sampling, and analysis, and on techniques for computing desorption and reaeration coefficients.

  11. Tracer Lamination in the Stratosphere: A Global Climatology

    NASA Technical Reports Server (NTRS)

    Appenzeller, Christof; Holton, James R.

    1997-01-01

    Vertical soundings of stratospheric ozone often exhibit laminated tracer structures characterized by strong vertical tracer gradients. The change in time of these gradients is used to define a tracer lamination rate. It is shown that this quantity can be calculated by the cross product of the horizontal temperature and horizontal tracer gradients. A climatology based on UARS satellite-borne ozone data and on ozone-like pseudotracer data is presented. Three stratospheric regions with high lamination rates were found: the part of the stratospheric overworld which is influenced by the polar vortex, the part of the lowermost stratosphere which is influenced by the tropopause and a third region in the subtropical lower stratosphere mainly characterized with strong vertical shear. High lamination rates in the stratospheric overworld were absent during summer, whereas in the lowermost stratosphere high lamination rates were found year-round. This is consistent with the occurrence and seasonal variation of the horizontal tracer gradient and vertical shear necessary for tilting the tracer surfaces. During winter, high lamination rates associated with the stratospheric polar vortex are present down to approximately 100 hPa. Several features of the derived climatology are roughly consistent with earlier balloon-borne studies. The patterns in the southern and northern hemisphere are comparable, but details differ as anticipated from a less disturbed and more symmetric southern polar vortex.

  12. Quantifying solute transport processes: are chemically "conservative" tracers electrically conservative?

    USGS Publications Warehouse

    Singha, Kamini; Li, Li; Day-Lewis, Frederick D.; Regberg, Aaron B.

    2012-01-01

    The concept of a nonreactive or conservative tracer, commonly invoked in investigations of solute transport, requires additional study in the context of electrical geophysical monitoring. Tracers that are commonly considered conservative may undergo reactive processes, such as ion exchange, thus changing the aqueous composition of the system. As a result, the measured electrical conductivity may reflect not only solute transport but also reactive processes. We have evaluated the impacts of ion exchange reactions, rate-limited mass transfer, and surface conduction on quantifying tracer mass, mean arrival time, and temporal variance in laboratory-scale column experiments. Numerical examples showed that (1) ion exchange can lead to resistivity-estimated tracer mass, velocity, and dispersivity that may be inaccurate; (2) mass transfer leads to an overestimate in the mobile tracer mass and an underestimate in velocity when using electrical methods; and (3) surface conductance does not notably affect estimated moments when high-concentration tracers are used, although this phenomenon may be important at low concentrations or in sediments with high and/or spatially variable cation-exchange capacity. In all cases, colocated groundwater concentration measurements are of high importance for interpreting geophysical data with respect to the controlling transport processes of interest.

  13. Nitrogen Uptake in Spinach

    NASA Astrophysics Data System (ADS)

    Ramirez, J.; VanBenthem, P.

    2013-12-01

    A plant's absorption of nitrogen can be encouraged by a variety of environmental factors, especially the application of fertilizers. As a common limiting factor in plant growth, not up taking enough nitrogen can be a result of an unhealthy plant. Moreover, as farmers seek out methods to increase growth of plants, fertilizers are used as a solution to the issue of nitrogen deficiency to incorporate additional nitrogen from chemical or organic sources, by not using the right fertilizer can greatly affect the plats. The point of this research project is to determine the effect of various fertilizers on the plant growth, and to correlate the measured nitrogen, water and chlorophyll content in spinach leaves. Spinach leaves were used because they are known to quickly uptake chemicals in the environment. The spinach plants were exposed to four different growing parameters, which are referred to as control, ammonium nitrate, MiracleGro , and organic. The spinach was originally placed in nitrogen deficient soil with only 2.2x10 4 weight percent (wt. %) nitrogen. The leaves in the control group were grown in this nitrogen deficient soil without any fertilizer added. Ammomium nitrate and MiracleGro were added to the spinach in the A and MG groups, respectively, and organic chicken stool was used for the O group. By using a spectral imaging system and flame combustion techniques, the chlorophyll content can be related to the nitrogen content in the spinach leaves. In these spinach leaves, nitrogen and chlorophyll content were measured, chlorophyll is a green pigment that plays a crucial role in producing nutrients for green plants. The lack of chlorophyll will allow the plant to become susceptible to diseases, so it is extremely important that the plants have a high content of chlorophyll. The role of nitrogen in chlorophyll is very important and helps in the creation of chlorophyll; therefore it is necessary that an appropriate amount of nitrogen is added for optimal growth

  14. Abnormal 18 F-FDG and 82 Rb PET Findings in Chagas Heart Disease.

    PubMed

    Salimy, Medhi S; Parwani, Purvi J; Mukai, Kanae; Pampaloni, Miguel Hernandez; Flavell, Robert R

    2017-03-03

    Uptake of the radiopharmaceutical F-FDG visualized by PET imaging can reflect abnormal myocardial inflammation. When utilized in conjunction with other imaging modalities, such as echocardiography, PET F-FDG imaging can help distinguish between active cardiac sarcoidosis and other etiologies of nonischemic cardiomyopathy. We present a case of a 46-year-old man with nonischemic cardiomyopathy and ventricular tachycardia who underwent an echocardiogram suggestive of cardiac Chagas disease. A subsequent F-FDG PET demonstrated abnormal hypermetabolism. The diagnosis was confirmed by positive serologic examination results.

  15. HYDROGEL TRACER BEADS: THE DEVELOPMENT, MODIFICATION, AND TESTING OF AN INNOVATIVE TRACER FOR BETTER UNDERSTANDING LNAPL TRANSPORT IN KARST AQUIFERS

    SciTech Connect

    Amanda Laskoskie, Harry M. Edenborn, and Dorothy J. Vesper

    2012-01-01

    The goal of this specific research task is to develop proxy tracers that mimic contaminant movement to better understand and predict contaminant fate and transport in karst aquifers. Hydrogel tracer beads are transported as a separate phase than water and can used as a proxy tracer to mimic the transport of non-aqueous phase liquids (NAPL). They can be constructed with different densities, sizes & chemical attributes. This poster describes the creation and optimization of the beads and the field testing of buoyant beads, including sampling, tracer analysis, and quantitative analysis. The buoyant beads are transported ahead of the dissolved solutes, suggesting that light NAPL (LNAPL) transport in karst may occur faster than predicted from traditional tracing techniques. The hydrogel beads were successful in illustrating this enhanced transport.

  16. Analysis of Particle Transport Using a Particulate Tracer Modeling

    NASA Astrophysics Data System (ADS)

    Wang, P.; Linker, L. C.; Lung, W.; Batiuk, R. A.

    2002-05-01

    Understanding the transport of dissolved and particulate materials in the Chesapeake Bay estuary is critical to allocating nutrient and sediment load reduction goals to the seven watershed states. A computer simulation of a particulate conservative tracer was conducted to help determine the transport mechanism. Tracers were loaded daily at the fall-line of Potomac River (a middle Bay's tributary). The settling rate is set at 0.1 m/day, with the assumption of neither scour nor re-suspension of tracer from the bed to allow continuous accumulation of tracers on bed. The low settling rate was used to allow tracer to transport widely in the estuary to provide information on the transport of fine particulates such as dead algae. After the tracers reach the mouth of Potomac River, most of them are further transported into the lower main-stem Bay. Flood tide is the main force for tracers transported north to the upper main-stem Bay and to the upstream of non-source rivers. In the main stem of the Bay, there exist concentration gradients from the Potomac River mouth to the opposite shore (the Maryland and Virginia eastern shore), to the lower Bay, and to the upper Bay. Concentration gradients also exist from the fall-line to the mouth in the source river, and from the mouth to the upstream in non-source rivers. These gradients are usually disturbed across trenches, due to a so-called "trench effect". A trench either deposits more or less tracers than its shallower sides, depending on the trench to be hydrologically landward from the source (i.e., the Potomac fall line) or the sub-source (e.g., the Rappahannock River mouth for the trench in the upstream of Rappahannock River), or hydrologically seaward from the source or the sub-source. Depending on the layer (saline water-rich or fresh water-rich) in which tracers reside and the direction (landward or seaward) along which tracers transport, the transport/deposit of tracer may be favored along trench over its shallower sides

  17. Lower extremity abnormalities in children.

    PubMed

    Sass, Pamela; Hassan, Ghinwa

    2003-08-01

    Rotational and angular problems are two types of lower extremity abnormalities common in children. Rotational problems include intoeing and out-toeing. Intoeing is caused by one of three types of deformity: metatarsus adductus, internal tibial torsion, and increased femoral anteversion. Out-toeing is less common than intoeing, and its causes are similar but opposite to those of intoeing. These include femoral retroversion and external tibial torsion. Angular problems include bowlegs and knock-knees. An accurate diagnosis can be made with careful history and physical examination, which includes torsional profile (a four-component composite of measurements of the lower extremities). Charts of normal values and values with two standard deviations for each component of the torsional profile are available. In most cases, the abnormality improves with time. A careful physical examination, explanation of the natural history, and serial measurements are usually reassuring to the parents. Treatment is usually conservative. Special shoes, cast, or braces are rarely beneficial and have no proven efficacy. Surgery is reserved for older children with deformity from three to four standard deviations from the normal.

  18. Normal and abnormal lid function.

    PubMed

    Rucker, Janet C

    2011-01-01

    This chapter on lid function is comprised of two primary sections, the first on normal eyelid anatomy, neurological innervation, and physiology, and the second on abnormal eyelid function in disease states. The eyelids serve several important ocular functions, the primary objectives of which are protection of the anterior globe from injury and maintenance of the ocular tear film. Typical eyelid behaviors to perform these functions include blinking (voluntary, spontaneous, or reflexive), voluntary eye closure (gentle or forced), partial lid lowering during squinting, normal lid retraction during emotional states such as surprise or fear (startle reflex), and coordination of lid movements with vertical eye movements for maximal eye protection. Detailed description of the neurological innervation patterns and neurophysiology of each of these lid behaviors is provided. Abnormal lid function is divided by conditions resulting in excessive lid closure (cerebral ptosis, apraxia of lid opening, blepharospasm, oculomotor palsy, Horner's syndrome, myasthenia gravis, and mechanical) and those resulting in excessive lid opening (midbrain lid retraction, facial nerve palsy, and lid retraction due to orbital disease).

  19. Non-conservative characteristics of fluorescent tracers help to assess in-situ transport and attenuation of pesticides

    NASA Astrophysics Data System (ADS)

    Lange, Jens; Payraudeau, Sylvain; Imfeld, Gwenaël

    2016-04-01

    Traditionally, hydrological tracers are selected to behave as conservatively as possible, since most applications aim to investigate the transport of water or conservative solutes. Non-conservative tracer behavior is regarded as a limitation. However, the environmental behavior of organic pesticides is strictly non-conservative as their fate is affected by various processes, including sorption, photolysis and biochemical transformation in various environmental compartments. If tracers are used to study pesticides under these conditions, we believe that a paradigm shift is necessary: only a tracer that is affected by similar attenuation processes can realistically reproduce the overall behavior of a target pesticide. We present here two examples from two different environmental compartments: (i) agricultural soils and (ii) wetland systems. In both studies two organic fluorescent tracers (uranine, UR and sulforhodamine-B, SRB) and the salt tracer bromide (BR) were applied together with the chloroacetanilide herbicide S-metolachlor (S-MET). On an agricultural field, plot experiments were conducted under artificial and natural rainfall conditions. The use of BR overestimated both slow leaching and fast preferential transport of S-MET in the unsaturated zone, while UR/SRB were more realistic markers. Under artificial conditions, recovery rates of BR in a tile drain were twice as high as UR and one order of magnitude higher than SRB. Under natural conditions, BR concentrations in surface soils (0-1 cm) displayed larger variances during wetting and drying periods than UR, SRB and S-MET. BR also leached deeper (below 5 cm) than S-MET in the soil column. After 70 days, characteristic fluorescent peaks of UR and SRB gradually decreased in soil samples, while a new peak increased in another spectrum, which suggests the production of a potential transformation product. In two artificial wetland systems the impact of hydrological conditions (batch versus continuous-flow) on

  20. Comparison of [11C]cocaine binding at tracer and pharmacological doses of baboon brain: A PET study

    SciTech Connect

    Volkow, N.D.; Fowler, J.S.; Logan, J.

    1994-05-01

    In vitro studies have shown that cocaine (C) binds to both high and low affinity sites on the dopamine transporter (DAT). We have previously characterized the binding of tracer doses of [{sup 11}C]cocaine (C*)to a high affinity site on the DAT. To assess if in vivo C also binds to low affinity sites we used PET to compare binding of tracer doses (17.8{plus_minus}12.2 {mu}g C) of C* to pharmacological doses (8 mg of C coadministered with C*). Sixteen paired studies were done to assess test/retest variability, specific versus non specific binding and to characterize binding profile. Dynamic scans were started immediately after injection of C* (5-8 mCi) for 50 min on the CTI-931 (6 x 6 x 6.5 mm FWHM). Time activity curves for tissue concentration and for unchanged tracer in plasma were used to calculate the transport constant between plasma and tissue (K1) and to obtain the distribution volume (DV). The ratio of the DV in striatum (ST) to that in cerebellum (CB) (which corresponds to Bmax/Kd-1) was used as model parameter. Peak brain uptake of C* was significantly higher for tracer than for pharmacological doses (0.041 versus 0.033 % dose/cc), as were the values for K1 (1.07{plus_minus}0.21 versus 0.68{plus_minus}0.26 (t=3.0 p<0.01)). Repeated measures were reproducible for tracer ({plus_minus}2%) and pharmacological doses of C* ({plus_minus}4%). Tracer dose C* showed highest binding and slowest clearance in ST which was reduced by C (0.5-2.0 mg/kg iv, -25 to -30%) and by drugs that inhibit DAT (2mg/kg nomifensine - 21%, 0.5 mg/kg methylphenidate -12%) and was increased by serotonin transporter inhibitors (5HT-Ti) (2 mg/kg citalopram +11%, 0.5 mg/kg fluoxetine +6%) and not changed by NE transporter inhibitors (0.5 mg/kg desipramine or 2 mg/kg tomoxetine). The increase with (5HT-Ti) may reflect neurotransmitter interactions or changes in bioavailability. At pharmacological doses C* showed homogeneous distribution and was not changed by C nor by any of the above drugs.

  1. Synthesis, characterization, and monkey positron emission tomography (PET) studies of [18F]Y1-973, a PET tracer for the neuropeptide Y Y1 receptor.

    PubMed

    Hostetler, Eric D; Sanabria-Bohórquez, Sandra; Fan, Hong; Zeng, Zhizhen; Gantert, Liza; Williams, Mangay; Miller, Patricia; O'Malley, Stacey; Kameda, Minoru; Ando, Makoto; Sato, Nagaaki; Ozaki, Satoshi; Tokita, Shigeru; Ohta, Hisashi; Williams, David; Sur, Cyrille; Cook, Jacquelynn J; Burns, H Donald; Hargreaves, Richard

    2011-02-14

    Neuropeptide Y receptor subtype 1 (NPY Y1) has been implicated in appetite regulation, and antagonists of NPY Y1 are being explored as potential therapeutics for obesity. An NPY Y1 PET tracer is useful for determining the level of target engagement by NPY Y1 antagonists in preclinical and clinical studies. Here we report the synthesis and evaluation of [(18)F]Y1-973, a novel PET tracer for NPY Y1. [(18)F]Y1-973 was radiolabeled by reaction of a primary chloride with [(18)F]KF/K2.2.2 followed by deprotection with HCl. [(18)F]Y1-973 was produced with high radiochemical purity (>98%) and high specific activity (>1000 Ci/mmol). PET studies in rhesus monkey brain showed that the distribution of [(18)F]Y1-973 was consistent with the known NPY Y1 distribution; uptake was highest in the striatum and cortical regions and lowest in the pons, cerebellum nuclei, and brain stem. Blockade of [(18)F]Y1-973 uptake with NPY Y1 antagonist Y1-718 revealed a specific signal that was dose-dependently reduced in all regions of grey matter to a similarly low level of tracer uptake, indicative of an NPY Y1 specific signal. In vitro autoradiographic studies with [(18)F]Y1-973 in rhesus monkey and human brain tissue slices revealed an uptake distribution consistent with the in vivo PET studies. Highest binding density was observed in the dentate gyrus, caudate-putamen, and cortical regions; moderate binding density in the hypothalamus and thalamus; and lowest binding density in the globus pallidus and cerebellum. In vitro saturation binding studies in rhesus monkey and human caudate-putamen homogenates confirmed a similarly high B(max)/K(d) ratio for [(18)F]Y1-973, suggesting the tracer may provide a specific signal in human brain of similar magnitude to that observed in rhesus monkey. [(18)F]Y1-973 is a suitable PET tracer for imaging NPY Y1 in rhesus monkey with potential for translation to human PET studies.

  2. Diffuse renal parenchyma uptake with bone scintigraphy in a patient with paroxysmal nocturnal hemoglobinuria and normal kidney function.

    PubMed

    Balink, Hans; Hoogendoorn, Mels; Hemmelder, Marc

    2014-03-01

    A 41-year-old woman with a Harrington spondylodesis presented with lower back pain. Bone scintigraphy showed diffusely increased parenchymal uptake in both kidneys. She reported 2 previous periods of dark, almost black, urine. Additional flow cytometric analysis confirmed the diagnosis of paroxysmal nocturnal hemoglobinuria. The increased renal parenchyma uptake is very probably due to paroxysmal nocturnal hemoglobinuria-related renal hemosiderosis. Remarkably, the patient did not develop any abnormality of renal function.

  3. Multiple Tracer Tests in Porous Media During Clogging

    NASA Astrophysics Data System (ADS)

    Englert, A.; Banning, A.; Siegmund, J.; Freye, S.; Goekpinar, T.

    2015-12-01

    Transport processes are known to be governed by the physical and chemical heterogeneity of the subsurface. Clogging processes can alter this heterogeneity as function of time and thus can modify transport. To understand transport under clogging conditions and to unravel the potential of multiple tracer tests to characterize such transport process we perform column and sandbox experiments. Our recently developed column and sandbox experiments are used to perform multiple tracer tests during clogging. In a first set of experiments, a cubic cell of 0.1 m x 0.1 m x 0.1 m is used to experimentally estimate flow and transport characteristics of an unconsolidated sediment through Darcy and tracer experiments. The water streaming through the experiment is amended with ammonium sulfate permanently. Salt tracers are added to the streaming water repeatedly, to be detected at micro electrodes at the inflow and the outflow of the cubic cell. Through repeated syringe injections of a barium chloride solution into the center of the cubic cell clogging processes are forced to occur around the mixing zone of the injected and streaming water by precipitation of barium sulfate. In a second set of experiments, a sandbox model including a sediment body of 0.3 m x 0.3 m x 0.1 m is used. Tracer, streaming, and injection water chemistry is kept similar to the cubic cell experiments. However, tracer breakthrough is now detected at nine positions within the experiment and at the inflow and the outflow of the sandbox model. Injection of barium chloride solution is now at two locations around the center of the sandbox model. Flow and transport characteristics of the sediment body are estimated based on Darcy and tracer experiments, which are performed repeatedly. Combined analysis of local and ensemble breakthrough curves and integrated numerical modeling will be used to understand effective and local flow and transport in a in a porous medium during clogging.

  4. Stable isotope tracers and exercise physiology: past, present and future.

    PubMed

    Wilkinson, Daniel J; Brook, Matthew S; Smith, Kenneth; Atherton, Philip J

    2016-09-09

    Stable isotope tracers have been invaluable assets in physiological research for over 80 years. The application of substrate-specific stable isotope tracers has permitted exquisite insight into amino acid, fatty-acid and carbohydrate metabolic regulation (i.e. incorporation, flux, and oxidation, in a tissue-specific and whole-body fashion) in health, disease and response to acute and chronic exercise. Yet, despite many breakthroughs, there are limitations to 'substrate-specific' stable isotope tracers, which limit physiological insight, e.g. the need for intravenous infusions and restriction to short-term studies (hours) in controlled laboratory settings. In recent years significant interest has developed in alternative stable isotope tracer techniques that overcome these limitations, in particular deuterium oxide (D2 O or heavy water). The unique properties of this tracer mean that through oral administration, the turnover and flux through a number of different substrates (muscle proteins, lipids, glucose, DNA (satellite cells)) can be monitored simultaneously and flexibly (hours/weeks/months) without the need for restrictive experimental control. This makes it uniquely suited for the study of 'real world' human exercise physiology (amongst many other applications). Moreover, using D2 O permits evaluation of turnover of plasma and muscle proteins (e.g. dynamic proteomics) in addition to metabolomics (e.g. fluxomics) to seek molecular underpinnings, e.g. of exercise adaptation. Here, we provide insight into the role of stable isotope tracers, from substrate-specific to novel D2 O approaches, in facilitating our understanding of metabolism. Further novel potential applications of stable isotope tracers are also discussed in the context of integration with the snowballing field of 'omic' technologies.

  5. Testing fundamentals: The chemical state of geochemical tracers in biominerals.

    NASA Astrophysics Data System (ADS)

    Branson, O.; Redfern, S. A. T.; Read, E.; Elderfield, H.

    2015-12-01

    The use of many carbonate-derived geochemical proxies is underpinned by the assumption that tracer elements are incorporated 'ideally' as impurities the mineral lattice, following relatively straightforward kinetic and thermodynamic drives. This allows comparison to inorganic precipitation experiments, and provides a systematic starting point from which to translate geochemical tracers to environmental records. Biomineral carbonates are a prominent source of geochemical proxy material, and are far from an ideal inorganic system. They are structurally and compositionally heterogeneous mineral-organic composites, produced in tightly controlled biological environments, possibly via non-classical crystal growth mechanisms. Biominerals offer numerous opportunities for tracers to be incorporated in a 'non-ideal' state. For instance, tracers could be hosted within the organic component of the structure, in interstitial micro-domains of a separate mineral phase, or in localized high-impurity clusters. If a proxy element is hosted in a non-ideal state, our understanding of its incorporation and preservation is flawed, and the theoretical basis behind the proxies derived from it must be reevaluated. Thus far, the assumption of ideal tracer incorporation has remained largely untested, owing to the spatial resolution and sensitivity limits of available techniques. Developments in high-resolution, high-sensitivity X-ray spectroscopy at Scanning Transmission X-Ray Microscopes (STXMs) have allowed us to measure trace element coordination in foraminiferal calcite, at length-scales relevant to biomineralisation processes and tracer incorporation. This instrument has allowed us to test the fundamental assumptions behind several geochemical proxy elements. We present a summary of four STXM studies, assessing the chemical state and distribution of Mg (Branson et al, 2014), B (Branson et al, 2015), S and Na (unpub.), and highlight the implications of these data for the use of these

  6. Transport of Passive Tracers in Baroclinic Wave Life Cycles

    NASA Technical Reports Server (NTRS)

    Stone, Elizabeth M.; Randel, William J.; Stanford, John L.

    1999-01-01

    The transport of passive tracers in idealized baroclinic wave life cycles is studied using output from the National Center for Atmospheric Research Community Climate Model (CCM2). Two life cycles, LCn and LCs, are simulated, starting with baroclinically unstable initial conditions similar to those used by Thorncroft et al. in their study of two life cycle paradigms. The two life cycles LCn and LCs have different initial horizontal wind shear structures that result in distinctive nonlinear development. In terms of potential vorticity-potential temperature (PV-theta) diagnostics, the LCn case is characterized by thinning troughs that are advected anti-cyclonically and equatorward, while the LCs case has broadening troughs that wrap up cyclonically and poleward. Four idealized passive tracers are included in the model to be advected by the semi-Lagrangian transport scheme of the CCM2, and their evolutions are investigated throughout the life cycles. Tracer budgets are analyzed in terms of the transformed Eulerian mean constituent transport formalism in pressure coordinates and also in isentropic coordinates. Results for both LCn and LCs show transport that is downgradient with respect to the background structure of the tracer field, but with a characteristic spatial structure that maximizes in the middle to high latitudes. For the idealized tropospheric tracers in this study, this represents a net upward and poleward transport that enhances concentrations at high latitudes. These results vary little with the initial distribution of the constituent field. The time tendency of the tracer is influenced most strongly by the eddy flux term. with the largest transport occurring during the nonlinear growth stage of the life cycle. The authors also study the transport of a lower-stratospheric tracer, to examine stratosphere-troposphere exchange for baroclinic waves.

  7. Field measurements of tracer gas transport by barometric pumping

    SciTech Connect

    Lagus, P.L.; McKinnis, W.B.; Hearst, J.R.; Burkhard, N.R.; Smith, C.F.

    1994-07-28

    Vertical gas motions induced by barometric pressure variations can carry radioactive gases out of the rubblized region produced by an underground nuclear explosion, through overburden rock, into the atmosphere. To better quantify transit time and amount of transport, field experiments were conducted at two sites on Pahute Mesa, Kapelli and Tierra, where radioactive gases had been earlier detected in surface cracks. At each site, two tracer gases were injected into the rubblized chimney 300-400 m beneath the surface and their arrival was monitored by concentration measurements in gas samples extracted from shallow collection holes. The first ``active`` tracer was driven by a large quantity of injected air; the second ``passive`` tracer was introduced with minimal gas drive to observe the natural transport by barometric pumping. Kapelli was injected in the fall of 1990, followed by Tierra in the fall of 1991. Data was collected at both sites through the summer of 1993. At both sites, no surface arrival of tracer was observed during the active phase of the experiment despite the injection of several million cubic feet of air, suggesting that cavity pressurization is likely to induce horizontal transport along high permeability layers rather than vertical transport to the surface. In contrast, the vertical pressure gradients associated with barometric pumping brought both tracers to the surface in comparable concentrations within three months at Kapelli, whereas 15 months elapsed before surface arrival at Tierra. At Kapelli, a quasisteady pumping regime was established, with tracer concentrations in effluent gases 1000 times smaller than concentrations thought to exist in the chimney. Tracer concentrations observed at Tierra were typically an order of magnitude smaller. Comparisons with theoretical calculations suggest that the gases are traveling through {approximately}1 millimeter vertical fractures spaced 2 to 4 meters apart. 6 refs., 18 figs., 3 tabs.

  8. Abnormal clearance of soluble aggregates of human immunoglobulin G in patients with systemic lupus erythematosus.

    PubMed

    Lobatto, S; Daha, M R; Breedveld, F C; Pauwels, E K; Evers-Schouten, J H; Voetman, A A; Cats, A; Van Es, L A

    1988-04-01

    In the present study, we tested mononuclear phagocyte system function in nine healthy controls and 15 SLE patients with complement activating 123I-labelled aggregates of human IgG (AIgG). Clearance half-time of AIgG was 26 +/- 8 min in controls, compared to 58 +/- 27 min in patients (P less than 0.005). Binding of AIgG to erythrocytes was significantly lower in patients, 9.3 +/- 8.1 vs 24 +/- 20% (P less than 0.05). The increase of C3a-levels in plasma was significantly lower in patients than in controls (P less than 0.05 at 3 and 8 min), suggesting less complement activation. Liver and spleen uptake of 123I-AIgG was measured with a gamma camera and expressed as liver/spleen uptake ratios. In patients, the liver/spleen uptake ratios were significantly higher than in controls at 15 min, 3.8 +/- 2.0 vs 2.31 +/- 0.7 (P less than 0.05), due to less splenic uptake of AIgG. Correlations between clearance half-time or liver/spleen uptake ratios and immune complex levels or disease activity were not found. This study indicates that clearance of soluble AIgG is abnormal in patients with SLE, due to decreased splenic uptake of AIgG.

  9. Viscosity controls humidity dependence of N2O5 uptake to citric acid aerosol

    NASA Astrophysics Data System (ADS)

    Gržinić, G.; Bartels-Rausch, T.; Berkemeier, T.; Türler, A.; Ammann, M.

    2015-08-01

    The heterogeneous loss of dinitrogen pentoxide (N2O5) to aerosol particles has a significant impact on the night time nitrogen oxide cycle and therefore the oxidative capacity in the troposphere. Using a 13N short lived radioactive tracer method we studied the uptake kinetics of N2O5 on citric acid aerosol particles as a function of relative humidity (RH). The results show that citric acid exhibits lower reactivity than similar di- and polycarboxylic acids, with uptake coefficients between ~ 3 × 10-4-~ 3 × 10-3 depending on humidity (17-70 % RH). This humidity dependence can be explained by a changing viscosity and, hence, diffusivity in the organic matrix. Since the viscosity of highly concentrated citric acid solutions is not well established, we present four different parameterizations of N2O5 diffusivity based on the available literature data or estimates for viscosity and diffusivity. Above 50 % RH, uptake is consistent with the reacto-diffusive kinetic regime whereas below 50 % RH, the uptake coefficient is higher than expected from hydrolysis of N2O5 within the bulk of the particles, and the uptake kinetics may be limited by loss on the surface only. This study demonstrates the impact of viscosity in highly oxidized and highly functionalized secondary organic aerosol material on the heterogeneous chemistry of N2O5 and may explain some of the unexpectedly low loss rates to aerosol derived from field studies.

  10. DOC:NO3- ratios and NO3- uptake in forested headwater streams

    NASA Astrophysics Data System (ADS)

    Rodríguez-Cardona, Bianca; Wymore, Adam S.; McDowell, William H.

    2016-01-01

    The underlying mechanisms driving the coupled interactions between inorganic nitrogen uptake and dissolved organic matter are not well understood, particularly in surface waters. To determine the relationship between dissolved organic carbon (DOC) quantity and nitrate (NO3-) uptake kinetics in streams, we performed a series of NO3- Tracer Additions for Spiraling Curve Characterization experiments in four streams within the Lamprey River Watershed, New Hampshire, across a range in background DOC concentrations (1-8 mg C/L). Experiments were performed throughout the 2013 and 2014 growing seasons. Across streams and experimental dates, ambient uptake velocity (Vf) correlated positively with increasing DOC concentrations and DOC:NO3- ratios but was only weakly negatively associated with NO3- concentrations. Ambient NO3- Vf was unrelated to pH, light, temperature, dissolved oxygen, and Specific Ultraviolet Absorbance at 254 nm. Although there were general tendencies across the entire Lamprey River Watershed, individual sites behaved differently in their uptake kinetics. NO3- uptake dynamics in the Lamprey River Watershed are most strongly influenced by DOC concentrations rather than NO3- concentrations or physicochemical parameters, which have been identified as regional- to continental-scale drivers in previous research. Understanding the fundamental relationships between dissolved organic matter and inorganic nutrients will be important as global and climatic changes influence the delivery and production of DOC and NO3- in aquatic ecosystems.

  11. LARGE-SCALE NATURAL GRADIENT TRACER TEST IN SAND AND GRAVEL, CAPE COD, MASSACHUSETTS - 1. EXPERIMENTAL DESIGN AND OBSERVED TRACER MOVEMENT

    EPA Science Inventory

    A large-scale natural gradient tracer experiment was conducted on Cape Cod, Massachusetts, to examine the transport and dispersion of solutes in a sand and gravel aquifer. The nonreactive tracer, bromide, and the reactive tracers, lithium and molybdate, were injected as a pulse i...

  12. Bicarbonate uptake by marine Crenarchaeota.

    PubMed

    Wuchter, Cornelia; Schouten, Stefan; Boschker, Henricus T S; Sinninghe Damsté, Jaap S

    2003-02-28

    Biphytanyl membrane lipids and 16S rRNA sequences derived from marine Crenarchaeota were detected in shallow North Sea surface water in February 2002. To investigate the carbon fixation mechanism of these uncultivated archaea in situ (13)C bicarbonate tracer experiments were performed with this water in the absence of light. About 70% of the detected (13)C incorporation into lipids (including fatty acids and sterols) is accounted for by the crenarchaeotal biphytanyl membrane lipids. This finding indicates that marine Crenarchaeota can utilize bicarbonate or CO(2) derived thereof in the absence of light and are chemoautotrophic organisms.

  13. TracerLPM (Version 1): An Excel® workbook for interpreting groundwater age distributions from environmental tracer data

    USGS Publications Warehouse

    Jurgens, Bryant C.; Böhlke, J.K.; Eberts, Sandra M.

    2012-01-01

    TracerLPM is an interactive Excel® (2007 or later) workbook program for evaluating groundwater age distributions from environmental tracer data by using lumped parameter models (LPMs). Lumped parameter models are mathematical models of transport based on simplified aquifer geometry and flow configurations that account for effects of hydrodynamic dispersion or mixing within the aquifer, well bore, or discharge area. Five primary LPMs are included in the workbook: piston-flow model (PFM), exponential mixing model (EMM), exponential piston-flow model (EPM), partial exponential model (PEM), and dispersion model (DM). Binary mixing models (BMM) can be created by combining primary LPMs in various combinations. Travel time through the unsaturated zone can be included as an additional parameter. TracerLPM also allows users to enter age distributions determined from other methods, such as particle tracking results from numerical groundwater-flow models or from other LPMs not included in this program. Tracers of both young groundwater (anthropogenic atmospheric gases and isotopic substances indicating post-1940s recharge) and much older groundwater (carbon-14 and helium-4) can be interpreted simultaneously so that estimates of the groundwater age distribution for samples with a wide range of ages can be constrained. TracerLPM is organized to permit a comprehensive interpretive approach consisting of hydrogeologic conceptualization, visual examination of data and models, and best-fit parameter estimation. Groundwater age distributions can be evaluated by comparing measured and modeled tracer concentrations in two ways: (1) multiple tracers analyzed simultaneously can be evaluated against each other for concordance with modeled concentrations (tracer-tracer application) or (2) tracer time-series data can be evaluated for concordance with modeled trends (tracer-time application). Groundwater-age estimates can also be obtained for samples with a single tracer measurement at one

  14. Hydrodynamic tracer diffusion in suspensions of swimming bacteria

    NASA Astrophysics Data System (ADS)

    Kasyap, T. V.; Koch, Donald L.; Wu, Mingming

    2014-08-01

    We present theoretical predictions, simulations, and experimental measurements of the diffusion of passive, Brownian tracer particles in the bulk of three-dimensional suspensions of swimming bacteria performing run-tumble random walks. In the theory, we derive an explicit expression for the "hydrodynamic" tracer diffusivity that results from the fluid disturbances created by a slender-body model of bacteria by ensemble averaging the mass conservation equation of the tracer over the space of tracer-bacterium interactions which are assumed to be binary. The theory assumes that the orientations of the bacterium before and after a tumble are uncorrelated and the fluid velocity disturbance created by the bacterium is small compared to its swimming speed. The dependence of the non-dimensional hydrodynamic diffusivity widetilde{D_h} obtained by scaling the dimensional hydrodynamic diffusivity by nL3UsL on the persistence in bacterial swimming and the Brownian diffusivity of the tracer are studied in detail through two nondimensional parameters—a Peclet number Pe = UsL/D which is the ratio of the time scale of bacterial swimming to the tracer diffusion time scale and a non-dimensional persistence time τ* = Usτ/L obtained by scaling the dimensional bacterial persistence time by the time that a bacterium takes to swim over a distance equal to its length. Here, n, Us, τ, and L are the concentration, swimming speed, tumbling time, and the overall length of the bacteria, respectively, and D is the Brownian diffusivity of the tracer. widetilde{D_h} is found to be a monotonically increasing function of τ* and a non-monotonic function of Pe with a Pe1/2 scaling in the Pe ≪ 1 limit, an intermediate peak and a constant value in the Pe ≫ 1 limit for the typical case of wild-type bacteria with τ* = O(1). In the simulation study we compute the bacterial contribution to the tracer diffusivity from explicit numerical simulations of binary tracer-bacterium interactions to

  15. Partitioning Gas Tracer Technology for Measuring Water in Landfills

    NASA Astrophysics Data System (ADS)

    Briening, M. L.; Jakubowitch, A.; Imhoff, P. T.; Chiu, P. C.; Tittlebaum, M. E.

    2002-12-01

    Unstable landfills can result in significant environmental contamination and can become a risk to public health. To reduce this risk, water may be added to landfills to ensure that enough moisture exists for biodegradation of organic wastes. In this case risks associated with future breaks in the landfill cap are significantly reduced because organic material is degraded more rapidly. To modify moisture conditions and enhance biodegradation, leachate is typically collected from the bottom of the landfill and then recirculated near the top. It is difficult, though, to know how much leachate to add and where to add it to achieve uniform moisture conditions. This situation is exacerbated by the heterogeneous nature of landfill materials, which is known to cause short circuiting of infiltrating water, a process that has been virtually impossible to measure or model. Accurate methods for measuring the amount of water in landfills would be valuable aids for implementing leachate recirculation systems. Current methods for measuring water are inadequate, though, since they provide point measurements and are frequently affected by heterogeneity of the solid waste composition and solid waste compaction. The value of point measurements is significantly reduced in systems where water flows preferentially, such as in landfills. Here, spatially integrated measurements might be of greater value. In this research we are evaluating a promising technology, the partitioning gas tracer test, to measure the water saturation within landfills, the amount of free water in solid waste divided by the volume of the voids. The partitioning gas tracer test was recently developed by researchers working in the vadose zone. In this methodology two gas tracers are injected into a landfill. One tracer is non-reactive with landfill materials, while the second partitions into and out of free water trapped within the pore space of the solid waste. Chromatographic separation of the tracers occurs

  16. Applied gas tracers for subsurface and surface hydrology

    NASA Astrophysics Data System (ADS)

    Elliot, T.; Kalin, R. M.; MacKinnon, P. A.; McNeill, G. W.; Murphy, J. L.

    2003-04-01

    Tracer methods can be broadly taken to be techniques for obtaining information about an environmental and/or engineering system or some part of a system (eg transit times in media, permeability, dispersivity, internal structure, subsurface activities, etc.) by observing the behaviour of a specific substance (natural or anthropogenic) either injected into or inherently added within that system. Recent studies at QUB have focussed on applied tracer methods using dissolved inert gases both as geochemically conservative tracers in groundwater systems (providing structural information, flow-paths, transit times, physical transport properties) and also as non-conservative, bulk partitioning agents to determine re-aeration coefficients (K_2 values) in surface stream systems or for characterising the presence and extent of nonaqueous phases in subsurface groundwater systems (eg NAPLs at contaminated land sites). Noble gas applications as applied tracers particularly are being investigated because of their low natural background levels and high sensitivity of determination (by GC-MS), and lack of any taste, odour, colour and toxicity problems -- these latter properties suggesting a more "environmentally-friendly" type of tracer either to protect potable water (eg public) supplies under investigation or so as not to impact intrinsic reactive processes in the system being traced. Both laboratory column investigations and field studies are presented, emphasising the utility of applied gas tracing for hydrological investigations. Mackinnon, P.A., Elliot, T., Zhao, Y.Q., Murphy, J.L. &Kalin, R.M. (2002) Evaluation of a novel technique for measuring reaeration in rivers. In C.A. Brebbia, P. Zanetti (Eds.) Development and Application of Computer Techniques to Environmental Studies IX. WIT Press, Southampton, UK. pp.531--540. McNeill, G.W., Yang, Y.S., Elliot, T., Kalin, R.M. (2001) Krypton gas as a novel applied tracer of groundwater flow in a fissured sandstone aquifer. In K

  17. A new tracer-density criterion for heterogeneous porous media

    USGS Publications Warehouse

    Barth, G.R.; Illangasekare, T.H.; Hill, M.C.; Rajaram, H.

    2001-01-01

    Tracerexperiments provide information about aquifer material properties vital for accurate site characterization. Unfortunately, density-induced sinking can distort tracer movement, leading to an inaccurate assessment of material properties. Yet existing criteria for selecting appropriate tracer concentrations are based on analysis of homogeneous media instead of media with heterogeneities typical of field sites. This work introduces a hydraulic-gradient correction for heterogeneous media and applies it to a criterion previously used to indicate density-induced instabilities in homogeneous media. The modified criterion was tested using a series of two-dimensional heterogeneous intermediate-scale tracer experiments and data from several detailed field tracer tests. The intermediate-scale experimental facility (10.0 ?? 1.2 ?? 0.06 m) included both homogeneous and heterogeneous (??2/In ?? = 1.22) zones. The field tracer tests were less heterogeneous (0.24 < ??2/ln ?? < 0.37), but measurements were sufficient to detect density-induced sinking. Evaluation of the modified criterion using the experiments and field tests demonstrates that the new criterion appears to account for the change in density-induced sinking due to heterogeneity. The criterion demonstrates the importance of accounting for heterogeneity to predict density-induced sinking and differences in the onset of density induced sinking in two-and three-dimensional systems.

  18. Tracer Particle Response in High-Gradient Flow

    NASA Astrophysics Data System (ADS)

    Herzog, Joshua; Rothamer, David

    2016-11-01

    Many laser-based fluid velocity measurements depend on the motion of tracer particles seeded into the flow. In most cases, the tracers are assumed to follow the flow exactly. However, this is not always the case. The actual motion of a tracer particle is dependent on the properties of both the particle and the fluid surrounding it. Previous analysis for spherical particles in the Stokes regime (assumes Re << 1) shows that the absolute difference between the particle and fluid velocity exponentially decays in time, with the relaxation time constant dependent on particle diameter, free stream velocity, Reynolds number, and both particle and fluid mass density. For all cases, it is necessary to accurately describe the physics of the tracer particle motion to perform rigorous quantitative studies with particle-based techniques. This study aims to measure and describe particle response to a step change in velocity in a uniform flow. Velocity profiles of solid tracer particles ranging from 300 to 3800 nm in diameter, with initial particle Reynolds numbers up to 100, were measured in a shock tube using particle image velocimetry. The goal of this study is to assess velocity relaxation estimates and assumptions for particle-based velocimetry techniques.

  19. Natural organic compounds as tracers for biomass combustion in aerosols

    SciTech Connect

    Simoneit, B.R.T. |; Abas, M.R. bin |; Cass, G.R. |; Rogge, W.F. |; Mazurek, M.A.; Standley, L.J.; Hildemann, L.M.

    1995-08-01

    Biomass combustion is an important primary source of carbonaceous particles in the global atmosphere. Although various molecular markers have already been proposed for this process, additional specific organic tracers need to be characterized. The injection of natural product organic tracers to smoke occurs primarily by direct volatilization/steam stripping and by thermal alteration based on combustion temperature. The degree of alteration increases as the burn temperature rises and the moisture content of the fuel decreases. Although the molecular composition of organic matter in smoke particles is highly variable, the molecular structures of the tracers are generally source specific. The homologous compound series and biomarkers present in smoke particles are derived directly from plant wax, gum and resin by volatilization and secondarily from pyrolysis of biopolymers, wax, gum and resin. The complexity of the organic components of smoke aerosol is illustrated with examples from controlled burns of temperate and tropical biomass fuels. Burning of biomass from temperate regions (i.e., conifers) yields characteristic tracers from diterpenoids as well as phenolics and other oxygenated species, which are recognizable in urban airsheds. The major organic components of smoke particles from tropical biomass are straight-chain, aliphatic and oxygenated compounds and triterpenoids. The precursor-to-product approach of organic geochemistry can be applied successfully to provide tracers for studying smoke plume chemistry and dispersion.

  20. Lattice-Boltzmann simulations of microswimmer-tracer interactions

    NASA Astrophysics Data System (ADS)

    de Graaf, Joost; Stenhammar, Joakim

    2017-02-01

    Hydrodynamic interactions in systems composed of self-propelled particles, such as swimming microorganisms and passive tracers, have a significant impact on the tracer dynamics compared to the equivalent "dry" sample. However, such interactions are often difficult to take into account in simulations due to their computational cost. Here, we perform a systematic investigation of swimmer-tracer interaction using an efficient force-counterforce-based lattice-Boltzmann (LB) algorithm [De Graaf et al., J. Chem. Phys. 144, 134106 (2016), 10.1063/1.4944962] in order to validate its ability to capture the relevant low-Reynolds-number physics. We show that the LB algorithm reproduces far-field theoretical results well, both in a system with periodic boundary conditions and in a spherical cavity with no-slip walls, for which we derive expressions here. The force-lattice coupling of the LB algorithm leads to a "smearing out" of the flow field, which strongly perturbs the tracer trajectories at close swimmer-tracer separations, and we analyze how this effect can be accurately captured using a simple renormalized hydrodynamic theory. Finally, we show that care must be taken when using LB algorithms to simulate systems of self-propelled particles, since its finite momentum transport time can lead to significant deviations from theoretical predictions based on Stokes flow. These insights should prove relevant to the future study of large-scale microswimmer suspensions using these methods.

  1. Spectral analysis for evaluation of myocardial tracers for medical imaging

    SciTech Connect

    Huesman, Ronald H.; Reutter, Bryan W.; Marshall, Robert C.

    2000-10-11

    Kinetic analysis of dynamic tracer data is performed with the goal of evaluating myocardial radiotracers for cardiac nuclear medicine imaging. Data from experiments utilizing the isolated rabbit heart model are acquired by sampling the venous blood after introduction of a tracer of interest and a reference tracer. We have taken the approach that the kinetics are properly characterized by an impulse response function which describes the difference between the reference molecule (which does not leave the vasculature) and the molecule of interest which is transported across the capillary boundary and is made available to the cell. Using this formalism we can model the appearance of the tracer of interest in the venous output of the heart as a convolution of the appearance of the reference tracer with the impulse response. In this work we parameterize the impulse response function as the sum of a large number of exponential functions whose predetermined decay constants form a spectrum, and each is required only to have a nonnegative coefficient. This approach, called spectral analysis, has the advantage that it allows conventional compartmental analysis without prior knowledge of the number of compartments which the physiology may require or which the data will support.

  2. Lattice-Boltzmann simulations of microswimmer-tracer interactions.

    PubMed

    de Graaf, Joost; Stenhammar, Joakim

    2017-02-01

    Hydrodynamic interactions in systems composed of self-propelled particles, such as swimming microorganisms and passive tracers, have a significant impact on the tracer dynamics compared to the equivalent "dry" sample. However, such interactions are often difficult to take into account in simulations due to their computational cost. Here, we perform a systematic investigation of swimmer-tracer interaction using an efficient force-counterforce-based lattice-Boltzmann (LB) algorithm [De Graaf et al., J. Chem. Phys. 144, 134106 (2016)JCPSA60021-960610.1063/1.4944962] in order to validate its ability to capture the relevant low-Reynolds-number physics. We show that the LB algorithm reproduces far-field theoretical results well, both in a system with periodic boundary conditions and in a spherical cavity with no-slip walls, for which we derive expressions here. The force-lattice coupling of the LB algorithm leads to a "smearing out" of the flow field, which strongly perturbs the tracer trajectories at close swimmer-tracer separations, and we analyze how this effect can be accurately captured using a simple renormalized hydrodynamic theory. Finally, we show that care must be taken when using LB algorithms to simulate systems of self-propelled particles, since its finite momentum transport time can lead to significant deviations from theoretical predictions based on Stokes flow. These insights should prove relevant to the future study of large-scale microswimmer suspensions using these methods.

  3. Chemical tracers of particulate emissions from commercial shipping.

    PubMed

    Viana, Mar; Amato, Fulvio; Alastuey, Andrés; Querol, Xavier; Moreno, Teresa; Dos Santos, Saúl García; Herce, María Dolores; Fernández-Patier, Rosalía

    2009-10-01

    Despite the increase of commercial shipping around the world, data are yet relatively scarce on the contribution of these emissions to ambient air particulates. One of the reasons is the complexity in the detection and estimation of shipping contributions to ambient particulates in harbor and urban environments, given the similarity with tracers of other combustion sources. This study aimed to identify specific tracers of shipping emissions in a Mediterranean city with an important harbor (Melilla, Spain). Results showed that for 24 h PM10 and PM2.5 samples, valid tracers of commercial shipping emissions were ratios of V/Ni = 4-5 and V/EC < 2, whereas V/EC > 8 excluded the influence of shipping emissions. Other ratios (V/ S, La/Ce, Zn/Ni, Pb/Zn, OC/EC) and tracers (Pb, Zn) were also tested but did not correlate with this source. Due to the changing composition of diesel fuels, tracers in the Mediterranean Sea may not be representative in other regions of the world and vice versa. The contribution of shipping emissions to ambient particulate matter (PM) urban background levels was quantified by positive matrix factorization (PMF), resulting in 2% and 4% of mean annual PM10 levels (0.8 microg/m3 primary particles and 1.7 microg/m3 secondary particles, with 20% uncertainty) and 14% of mean annual PM2.5 levels (2.6 microg/m3).

  4. Monodisperse magnetite nanoparticle tracers for in vivo magnetic particle imaging

    PubMed Central

    Khandhar, Amit P; Ferguson, R Matthew; Arami, Hamed; Krishnan, Kannan M

    2013-01-01

    Magnetic Particle Imaging (MPI) is a new biomedical imaging modality that produces real-time, high-resolution tomographic images of superparamagnetic iron oxide (SPIO) nanoparticle tracer distributions. In this study, we synthesized monodisperse tracers for enhanced MPI performance and investigated both, their blood clearance time using a 25 kHz magnetic particle spectrometer (MPS), and biodistribution using a combination of quantitative T2-weighted MRI and tissue histology. In vitro and in vivo MPI performance of our magnetic nanoparticle tracers (MNTs), subject to biological constraints, were compared to commercially available SPIOs (Resovist). Monodisperse MNTs showed a 2-fold greater signal per unit mass, and 20% better spatial resolution. In vitro evaluation of tracers showed that MPI performance of our MNTs is preserved in blood, serum-rich cell culture medium and gel; thus independent of changes in hydrodynamic volume and fluid viscosity – a critical prerequisite for in vivo MPI. In a rodent model, our MNTs circulated for 15 minutes – 3× longer than Resovist – and supported our in vitro evaluation that MPI signal is preserved in the physiological environment. Furthermore, MRI and histology analysis showed that MNTs distribute in the reticuloendothelial system (RES) in a manner similar to clinically approved SPIO agents. MNTs demonstrating long-circulation times and optimized MPI performance show potential as angiography tracers and blood-pool agents for the emerging MPI imaging modality. PMID:23434348

  5. Quantifying capture efficiency of gas collection wells with gas tracers.

    PubMed

    Yazdani, Ramin; Imhoff, Paul; Han, Byunghyun; Mei, Changen; Augenstein, Don

    2015-09-01

    A new in situ method for directly measuring the gas collection efficiency in the region around a gas extraction well was developed. Thirteen tests were conducted by injecting a small volume of gas tracer sequentially at different locations in the landfill cell, and the gas tracer mass collected from each test was used to assess the collection efficiency at each injection point. For 11 tests the gas collection was excellent, always exceeding 70% with seven tests showing a collection efficiency exceeding 90%. For one test the gas collection efficiency was 8±6%. Here, the poor efficiency was associated with a water-laden refuse or remnant daily cover soil located between the point of tracer injection and the extraction well. The utility of in situ gas tracer tests for quantifying landfill gas capture at particular locations within a landfill cell was demonstrated. While there are certainly limitations to this technology, this method may be a valuable tool to help answer questions related to landfill gas collection efficiency and gas flow within landfills. Quantitative data from tracer tests may help assess the utility and cost-effectiveness of alternative cover systems, well designs and landfill gas collection management practices.

  6. Tumor uptake of radioruthenium compounds

    SciTech Connect

    Srivastava, S C; Richards, P; Meinken, G E; Larson, S M; Grunbaum, Z

    1980-01-01

    The use of ruthenium-97 as a scintigraphic agent, particularly for tumor localization, is investigated. The tumor uptake of ruthenium chloride and ruthenium-labelled transferrin is evaluated and their application as tumor-imagine agents is compared to gallium-67 citrate. (ACR)

  7. MRI findings of new uptake in the femoral head detected on follow-up bone scans.

    PubMed

    Kim, Seong Ho; Yoo, Hye Jin; Kang, Yusuhn; Choi, Ja-Young; Hong, Sung Hwan

    2015-03-01

    OBJECTIVE. The purpose of this article is to suggest clinical indications for MRI in patients with breast cancer who have new uptake lesions in the femoral head on follow-up bone scans, by evaluating the incidence and causes of new uptake lesions. MATERIALS AND METHODS. Between January 2002 and July 2013, a total of 145 patients with breast cancer who showed new uptake in the femoral head on follow-up bone scans were included in our study. They were classified into two groups: group 1 consisted of 125 patients without known bone metastases, and group 2 consisted of 20 patients who already had bone metastases other than that in the femoral head. The Fisher exact test was performed for the statistical analysis. Thereafter, we reviewed MR images for characterization of the new abnormal uptake in the femoral head. RESULTS. New uptake lesions in the femoral head were metastatic in only 4.8% (6/125) of group 1 patients but in 75% (15/20) of group 2 patients (p < 0.0001). In both groups, no patient with a single uptake lesion in the femoral head had bone metastasis, whereas all patients with more than five new uptake lesions, including those of the femoral head, showed bone metastasis. Most MRI diagnoses for new uptake in the femoral head were fibrocystic change (15/30, 50%) and subchondral fracture (11/30, 36.7%). CONCLUSION. Most of the new uptake lesions in the femoral head detected on the follow-up bone scans in patients with breast cancer were benign. However, MRI could be considered in patients with known bone metastasis or with multiple new uptake lesions on bone scans.

  8. Influence of hypoxia on tracer accumulation in squamous-cell carcinoma: in vitro evaluation for PET imaging.

    PubMed

    Minn, H; Clavo, A C; Wahl, R L

    1996-11-01

    Hypoxic accumulation of 2-[5,6-3H]fluoro-2-deoxy-D-glucose ([3H]FDG),L-[methyl-3H] methionine ([3H]MET), and L-[1-3H]leucine ([3H]LEU) was evaluated in two cell lines (UT-SCC-5 and UT-SCC-20) obtained from patients with squamous-cell carcinoma of the head and neck. Both cell lines were exposed to decreasing oxygen atmosphere (20%, 1.5%, or 0% O2) for 6 h, after which they were incubated for a further 1 h with tritiated FDG, MET, or LEU. An anoxic atmosphere resulted in a mean increase of [3H]FDG uptake of 120% and 46% over a baseline 20% oxygen atmosphere for UT-SCC-5 and UT-SCC-20A, respectively. Both total and acid-precipitable [3H]MET uptake remained unchanged at 0% versus baseline, whereas acid-precipitable [3H]LEU uptake decreased by 46% for UT-SCC-5 and by 34% for UT-SCC-20A at 0% O2. Our findings demonstrate that [3H]FDG accumulation is increased in hypoxic UT-SCC cell lines probably through activation of the metabolic steps associated with the glycolytic pathway. The decrease in acid-precipitable [3H]LEU uptake in hypoxia may indicate a decline in protein synthesis, whereas the unchanged [3H]MET uptake probably reflects the unaffected amino acid transport and slow incorporation of radiolabeled methyl group of MET in tumor proteins and nucleic acids. FDG and LEU, but probably not MET, warrant additional study as hypoxia-avid or hypoxia-reduced tracers for assessment of treatment effects designed to modify hypoxia.

  9. Pulmonary uptake of morphine (M)

    SciTech Connect

    Roerig, D.L.; Bunke, S.S.; Kotrly, K.J.; Dawson, C.A.; Kampine, J.P.

    1986-03-01

    Previously the authors reported less than 5% of M was taken up during the first pass through the human lung. The low uptake of this basic lipophilic amine was further investigated in a single pass isolated perfused rat lung (IPL) in comparison to uptake of radiolabelled H/sub 2/O, antipyrine (A), aminopyrine (AM), nicotine (N) and phenylethylamine (P). The IPL was perfused for 5 min with each drug (5nmol/ml) and effluent collected in 10 sec fractions. Pulmonary extraction was calculated using indocyanine green dye as a non-extractable reference indicator. Accumulation of all compounds in the IPL reached an apparent equilibrium within 4 min. At equilibrium lung/perfusate conc. ratios for H/sub 2/O, A, AM, N, P and M were 1.04, 0.84, 0.85, 1.44, 2.57 and 1.13 respectively. The time course of M uptake differed from the other compounds since initial extraction of M was low (23%) compared to 75%, 53%, 35%, 82% and 86% for H/sub 2/O, A, AM, N and P respectively. Also, the half time to equilibrium for M was longer (50 sec) compared to 18, 21, 26, 19 and 22 sec for H/sub 2/O, A, AM, N and P respectively. The low initial pulmonary extraction of M compared to these compounds followed by greater M extraction during the remainder of drug infusion suggests uptake mechanisms for M different than the flow limited uptake for water and other basic amine drugs.

  10. Orbits and radial migration of galactic tracers using Gaia+

    NASA Astrophysics Data System (ADS)

    Romero-Gómez, M.; Figueras, F.; Miret-Roig, N.; Roca-Fàbrega, S.; Antoja, T.

    2017-03-01

    It will be in the forthcoming years that a large set of stars with full 6D phase space information will be available. In this contribution, we focus on the study of the radial migration stellar kinematic tracers may suffer. By assuming a potential for the Milky Way, we analyze the capabilities of Gaia and future spectroscopic data to trace back in time the orbital evolution of both, Red Clump stars, excellent tracers of large scale disc structure, and the members of the Young Local Associations, nearby stars with accurate astrometry in the upcoming TGAS catalog. By considering different mechanisms causing radial migration, namely the bar and/or the spiral arms, we study future capabilities to ascertain a single origin to these tracers.

  11. Identification and characterization of conservative organic tracers for use as hydrologic tracers for the Yucca Mountain Site Characterization Study; Progress report, July 1, 1991--December 31, 1991

    SciTech Connect

    Dombrowski, T.; Stetzenbach, K.

    1991-12-31

    Studies continued on organic tracers for use as hydrologic tracers as part of the Yucca Mountain Site Characterization project. Tracers studied include benzoic acids, cinnamic acids, and salicylic acids. The main focus of the work performed during the time period from 07/01/91 to 12/31/91 has been the continuation of (1) LC-MS optimization for tracer identification, (2) batch sorption and degradation studies, (3) neoprene tubing evaluation studies, and (4) soil column evaluation of tracer compounds. All of these areas of research (except perhaps the neoprene tubing evaluation) are ongoing and will continue throughout the coming year.

  12. Noble gas tracers of ventilation during deep-water formation in the Weddell Sea

    NASA Astrophysics Data System (ADS)

    Nicholson, D. P.; Khatiwala, S.; Heimbach, P.

    2016-05-01

    To explore the dynamics and implications of incomplete air-sea equilibration during the formation of abyssal water masses, we simulated noble gases in the Estimating the Circulation & Climate of the Ocean (ECCO) global ocean state estimate. A novel computation approach utilizing a matrix-free Newton-Krylov (MFNK) scheme was applied to quickly compute the periodic seasonal solutions for noble gas tracers. MFNK allows for quick computation of a cyclo-stationary solution for tracers (i.e., a spun-up, repeating seasonal cycle), which would otherwise be computationally infeasible due to the long time scale of dynamic adjustment of the abyssal ocean (1000’s of years). A suite of experiments isolates individual processes, including atmospheric pressure effects, the solubility pump and air-sea bubble fluxes. In addition to these modeled processes, a volumetric contribution of 0.28 ± 0.07% of glacial melt water is required to reconcile deep-water observations in the Weddell Sea. Another primary finding of our work is that the saturation anomaly of heavy noble gases in model simulations is in excess of two-fold more negative than is suggested from Weddell Sea observations. This result suggests that model water masses are insufficiently ventilated prior to subduction and thus there is insufficient communication between atmosphere and ocean at high latitudes. The discrepancy between noble gas observations and ECCO simulations highlights that important inadequacies remain in how we model high-latitude ventilation with large implications for the oceanic uptake and storage of carbon.

  13. Determining metal assimilation efficiency in aquatic invertebrates using enriched stable metal isotope tracers

    USGS Publications Warehouse

    Croteau, M.-N.; Luoma, S.N.; Pellet, B.

    2007-01-01

    We employ a novel approach that combines pulse-chase feeding and multi-labelled stable isotopes to determine gut passage time (GPT), gut retention time (GRT), food ingestion rate (IR) and assimilation efficiency (AE) of three trace elements for a freshwater gastropod. Lettuce isotopically enriched in 53Cr, 65Cu and 106Cd was fed for 2 h to Lymnaea stagnalis. The release of tracers in feces and water was monitored for 48 h, during which unlabelled lettuce was provided ad libidum. The first defecation of 53Cr occurred after 5 h of depuration (GPT), whereas 90% of the ingested 53Cr was recovered in the feces after 22.5 h of depuration (GRT). 53Chromium was not significantly accumulated in the soft tissues upon exposure. In contrast, 65Cu and 106Cd assimilation was detectable for most experimental snails, i.e., 65/63Cu and 106/114Cd ratios in exposed snails were higher than those for controls. Food IR during the labelled feeding phase was 0.16 ?? 0.07 g g-1 d-1. IR was inferred from the amount of 53Cr egested in the feces during depuration and the concentration of 53Cr in the labelled lettuce. Assimilation efficiencies (??95% CI) determined using mass balance calculations were 84 ?? 4% for Cu and 85 ?? 3% for Cd. The ratio method yields similar AE estimates. Expanding the application of this novel stable isotope tracer technique to other metals in a wide variety of species will provide unique opportunities to evaluate the interplay between digestive processes and dietary influx of metals. Understanding the biological processes that modulate dietborne metal uptake is crucial to assess the toxicity of dietborne metals. ?? 2007 Elsevier B.V. All rights reserved.

  14. Biochemical and functional abnormalities in hypercholesterolemic rabbit platelets

    SciTech Connect

    Dalal, K.B.; Ebbe, S.; Mazoyer, E.; Carpenter, D.; Yee, T. )

    1990-02-01

    This study was designed to elucidate changes in rabbit platelet lipids induced by a cholesterol rich diet and to explore the possible correlation of these lipid changes with platelet abnormalities. Pronounced biochemical alterations were observed when serum cholesterol levels of 700-1000 mg% were reached. Hypercholesterolemic (HC) platelets contained 37% more neutral lipids and 16% less phospholipids than the controls. Lysolecithin, cholesterol esters and phosphatidylinositol (PI) levels were increased in HC platelets, and the levels of phosphatidylcholine (PC) were decreased. The cholesterol/phospholipid molar ratio of lipidemic platelets increased from 0.55 +/- 0.011 to 0.89 +/- 0.016 (P less than 0.01) in eight weeks. HC platelets had 90% more arachidonic acid (AA) in the PI than normal platelets. No significant changes in AA of PC were observed. Platelet function was monitored by the uptake and release of (14C)serotonin in platelet rich plasma (PRP), using varying concentrations of collagen as an aggregating agent. The uptake of (14C)serotonin in HC and normal platelets ranged from 78-94%. The percent of (14C)serotonin released from normal and HC platelets was proportional to the concentration of collagen. However, lipidemic platelets were hyperreactive to low concentrations of collagen. Incorporation of 50 microM acetylsalicylic acid into the aggregating medium suppressed the release of (14C)serotonin in normal PRP by more than 90%, but had only a partial effect on lipidemic PRP.

  15. Electrocardiographic abnormalities in patients with Lassa fever.

    PubMed

    Cummins, D; Bennett, D; Fisher-Hoch, S P; Farrar, B; McCormick, J B

    1989-10-01

    Electrocardiograms from 32 patients with acute Lassa fever were abnormal in over 70% of cases. The changes noted included non-specific ST-segment and T-wave abnormalities, ST-segment elevation, generalized low-voltage complexes, and changes reflecting electrolyte disturbance. None of the abnormalities correlated with clinical severity of infection, serum transaminase levels, or eventual outcome. ECG changes are common in Lassa fever, but usually unassociated with clinical manifestations of myocarditis.

  16. Nitrogen uptake by Eucalyptus regnans and Acacia spp. - preferences, resource overlap and energetic costs.

    PubMed

    Pfautsch, Sebastian; Rennenberg, Heinz; Bell, Tina L; Adams, Mark A

    2009-03-01

    In southeastern Australia, the overstory species Eucalyptus regnans F. Muell. commonly grows with either of the two leguminous understory trees, Acacia melanoxylon (R. Br. Ex Ait. f.) or Acacia dealbata (Link.). Our objective was to elucidate interactions between the dominant eucalypt and its companion acacias for nitrogen (N) sources. Use of stable N isotopes as tracers revealed that ammonium was the preferred soil N source for all species, nevertheless, total N uptake varied greatly among species. Studies with double-labeled ((13)C/(15)N) glutamine indicated the uptake of this form of organic N in small amounts by both E. regnans and the Acacia spp. These and other data imply that, in contrast to boreal forests, organic N is not a significant component of N nutrition in mountain ash forests. Field and laboratory studies provided evidence that N(2)-fixation capacity of acacias varies with stand development, with N-fixing species playing an important role in N nutrition during the early but not the mature stages of forest growth. An index of N-uptake efficiency - the amount of oxygen consumed per unit N taken up - was compared across four N sources and three species. Nitrate uptake was the least efficient form of N acquisition, especially compared with ammonium uptake which was up to 30-fold less costly. Efficiency of glutamine uptake was intermediate between that of ammonium and nitrate. Differences in uptake efficiency among N forms were most pronounced for the Acacia spp. and least for E. regnans. We conclude that an overlap in requirements among sympatric Acacia spp. and E. regnans for specific soil N sources can be bypassed because of changes in biochemical strategies of Acacia spp. triggered by increasing soil N concentrations during stand development. Further studies might elucidate whether this is a common feature of complex forest ecosystems, or a specialty of the interaction between eucalypts and acacias.

  17. Intra-neuronal vesicular uptake of catecholamines is decreased in patients with Lewy body diseases.

    PubMed

    Goldstein, David S; Holmes, Courtney; Kopin, Irwin J; Sharabi, Yehonatan

    2011-08-01

    Several neurodegenerative disorders, including Parkinson disease (PD), are characterized by the presence of Lewy bodies - cytoplasmic inclusions containing α-synuclein protein aggregates - in the affected neurons. A poorly understood feature of Lewy body diseases is loss of sympathetic nerves in the heart and other organs, manifesting as orthostatic hypotension (OH; also known as postural hypotension). We asked whether sympathetic denervation is associated with decreased uptake of catecholamines, such as dopamine and norepinephrine, into storage vesicles within sympathetic neurons. We used 6-[18F]-dopamine (18F-DA) to track myocardial uptake and retention of catecholamines. Concurrently, the fate of intra-neuronal 18F-DA was followed by assessment of arterial plasma levels of the 18F-DA metabolite 18F-dihydroxyphenylacetic acid (18F-DOPAC). The ratio of myocardial 18F-DA to arterial 18F-DOPAC provided an index of vesicular uptake. Tracer concentrations were measured in patients with PD with or without orthostatic hypotension (PD+OH, PD-No-OH); in patients with pure autonomic failure (PAF, a Lewy body disease without parkinsonism); in patients with multiple system atrophy (MSA, a non-Lewy body synucleinopathy); and in normal controls. Patients with PD+OH or PAF had decreased vesicular 18F-DA uptake and accelerated 18F-DA loss, compared with MSA and control subjects. PD-No-OH patients could be subtyped into one of these categories based on their initial 18F-DA uptake. We conclude that sympathetic denervation in Lewy body diseases is associated with decreased vesicular uptake of neuronal catecholamines, suggesting that vesicular monoamine transport is impaired. Vesicular uptake may constitute a novel target for diagnosis, treatment, and prevention.

  18. Frequency and patterns of abnormality detected by iodine-123 amine emission CT after cerebral infarction

    SciTech Connect

    Brott, T.G.; Gelfand, M.J.; Williams, C.C.; Spilker, J.A.; Hertzberg, V.S.

    1986-03-01

    Single photon emission computed tomography (SPECT) was performed in 31 patients with cerebral infarction and 13 who had had transient ischemic attacks, using iodine-123-labeled N,N,N'-trimethyl-N'-(2-hydroxyl-3-methyl-5-iodobenzyl)-1,3-propanediamin e (I-123-HIPDM) as the radiopharmaceutical. SPECT scans were compared with computed tomographic (CT) scans. SPECT was as sensitive as CT in detecting cerebral infarction (94% vs. 84%). The abnormalities were larger on the SPECT scans than on the CT scans in 19 cases, equal in seven, and smaller in five (SPECT abnormalities greater than or equal to CT abnormalities in 86% of cases). Fifteen of 30 patients with hemispheric infarction had decreased perfusion (decreased uptake of I-123-HIPDM) to the cerebellar hemisphere contralateral to the cerebral hemisphere involved by the infarction (crossed cerebellar diaschisis). Nine of these 15 patients had major motor deficits, while only one of the 15 without crossed cerebellar diaschisis had a major motor deficit.

  19. Photodynamic-therapy-induced alterations of the blood-brain barrier transfer constant of a tracer molecule in normal brain

    NASA Astrophysics Data System (ADS)

    Yeung, Ivan; Lilge, Lothar D.; Wilson, Brian C.; Lee, Ting-Yim; Stevens, Laura; Cenic, Aleksa

    1997-05-01

    Photofrin uptake studies in brain tissues using bulk sampling techniques have demonstrated up to a 10-fold higher concentration in intracranial tumors compared to normal brain structures. This selective uptake is in part attributed to the leaky blood-brain barrier (BBB) in brain tumors while intact BBB in normal brain excludes Photofrin from the extravascular space. However, in vivo preclinical studies have shown a very high sensitivity in normal brain to photodynamic therapy (PDT) despite this selective uptake. In vivo computed tomography (CT) measurement of the blood- brain transfer constant (K) and cerebral plasma volume using an x-ray dye as a tracer was used to monitor the degradation process of the BBB in normal brain during and post PDT. In these experiments, it was observed that K increased as early as 15 minutes after the onset of PDT, peaking at approximately 3 hr post PDT treatment followed by a drop close to baseline values for 3 out of 4 animals. On the other hand, the cerebral plasma volume showed a decrease also as early as 15 min post PDT onset, but its decrease continued up to 6 hrs with no apparent vascular stasis at the end of the time period. The results suggested a continuous process of BBB breakdown and vascular shutdown shortly after start of PDT.

  20. New pathogen-specific immunoPET/MR tracer for molecular imaging of a systemic bacterial infection

    PubMed Central

    Wiehr, Stefan; Warnke, Philipp; Rolle, Anna-Maria; Schütz, Monika; Oberhettinger, Philipp; Kohlhofer, Ursula; Quintanilla-Martinez, Leticia; Maurer, Andreas; Thornton, Christopher; Boschetti, Frederic; Reischl, Gerald; Autenrieth, Ingo B.; Pichler, Bernd J.; Autenrieth, Stella E.

    2016-01-01

    The specific and rapid detection of Enterobacteriaceae, the most frequent cause of gram-negative bacterial infections in humans, remains a major challenge. We developed a non-invasive method to rapidly detect systemic Yersinia enterocolitica infections using immunoPET (antibody-targeted positron emission tomography) with [64Cu]NODAGA-labeled Yersinia-specific polyclonal antibodies targeting the outer membrane protein YadA. In contrast to the tracer [18F]FDG, [64Cu]NODAGA-YadA uptake co-localized in a dose dependent manner with bacterial lesions of Yersinia-infected mice, as detected by magnetic resonance (MR) imaging. This was accompanied by elevated uptake of [64Cu]NODAGA-YadA in infected tissues, in ex vivo biodistribution studies, whereas reduced uptake was observed following blocking with unlabeled anti-YadA antibody. We show, for the first time, a bacteria-specific, antibody-based, in vivo imaging method for the diagnosis of a Gram-negative enterobacterial infection as a proof of concept, which may provide new insights into pathogen-host interactions. PMID:26934329

  1. [Renal abnormalities in ankylosing spondylitis].

    PubMed

    Samia, Barbouch; Hazgui, Faiçal; Abdelghani, Khaoula Ben; Hamida, Fethi Ben; Goucha, Rym; Hedri, Hafedh; Taarit, Chokri Ben; Maiz, Hedi Ben; Kheder, Adel

    2012-07-01

    We will study the epidemiologic, clinical, biological, therapeutic, prognostic characteristics and predictive factors of development of nephropathy in ankylosing spondylitis patients. We retrospectively reviewed the medical record of 32 cases with renal involvement among 212 cases of ankylosing spondylitis followed in our service during the period spread out between 1978 and 2006. The renal involvement occurred in all patients a mean of 12 years after the clinical onset of the rheumatic disease. Thirty-two patients presented one or more signs of renal involvement: microscopic hematuria in 22 patients, proteinuria in 23 patients, nephrotic syndrome in 11 patients and decreased renal function in 24 patients (75%). Secondary renal amyloidosis (13 patients), which corresponds to a prevalence of 6,1% and tubulointerstitial nephropathy (7 patients) were the most common cause of renal involvement in ankylosing spondylitis followed by IgA nephropathy (4 patients). Seventeen patients evolved to the end stage renal disease after an average time of 29.8 ± 46 months. The average follow-up of the patients was 4,4 years. By comparing the 32 patients presenting a SPA and renal disease to 88 with SPA and without nephropathy, we detected the predictive factors of occurred of nephropathy: tobacco, intense inflammatory syndrome, sacroileite stage 3 or 4 and presence of column bamboo. The finding of 75% of the patients presented a renal failure at the time of the diagnosis of renal involvement suggests that evidence of renal abnormality involvement should be actively sought in this disease.

  2. Abnormal band of lateral meniscus.

    PubMed

    Giordano, Brian; Goldblatt, John

    2009-01-01

    This article describes a case of an "abnormal band" of the lateral meniscus, extending from the posterior horn of the true lateral meniscus to its antero-mid portion, observed during arthroscopy in a 45-year-old white man of Bosnian descent. The periphery of the aberrant lateral meniscus was freely mobile, and not connected to the underlying true lateral meniscus. Preoperative physical examination findings were consistent with medial-sided meniscal pathology only; however, evidence of an anomalous lateral meniscus was seen with magnetic resonance imaging. This anatomical pattern is rare and has been reported in the literature only once, in a report of 2 Asian patients. This article illustrates an anatomical variant of the lateral meniscus in a non-Asian patient with a clinical presentation that has not been previously described. In addition to the case report, the article presents a comprehensive review of the existing body of literature on anomalous lateral meniscus patterns. We believe that the definitions of the types of aberrant meniscus can be clarified to establish improved accuracy in reporting.

  3. Biochemical abnormalities in Pearson syndrome.

    PubMed

    Crippa, Beatrice Letizia; Leon, Eyby; Calhoun, Amy; Lowichik, Amy; Pasquali, Marzia; Longo, Nicola

    2015-03-01

    Pearson marrow-pancreas syndrome is a multisystem mitochondrial disorder characterized by bone marrow failure and pancreatic insufficiency. Children who survive the severe bone marrow dysfunction in childhood develop Kearns-Sayre syndrome later in life. Here we report on four new cases with this condition and define their biochemical abnormalities. Three out of four patients presented with failure to thrive, with most of them having normal development and head size. All patients had evidence of bone marrow involvement that spontaneously improved in three out of four patients. Unique findings in our patients were acute pancreatitis (one out of four), renal Fanconi syndrome (present in all patients, but symptomatic only in one), and an unusual organic aciduria with 3-hydroxyisobutyric aciduria in one patient. Biochemical analysis indicated low levels of plasma citrulline and arginine, despite low-normal ammonia levels. Regression analysis indicated a significant correlation between each intermediate of the urea cycle and the next, except between ornithine and citrulline. This suggested that the reaction catalyzed by ornithine transcarbamylase (that converts ornithine to citrulline) might not be very efficient in patients with Pearson syndrome. In view of low-normal ammonia levels, we hypothesize that ammonia and carbamylphosphate could be diverted from the urea cycle to the synthesis of nucleotides in patients with Pearson syndrome and possibly other mitochondrial disorders.

  4. Collisional decoherence of a tracer particle moving in one dimension

    SciTech Connect

    Kamleitner, Ingo

    2010-11-15

    We study decoherence of the external degree of freedom of a tracer particle moving in a one-dimensional dilute Boltzmann gas. We find that phase averaging is the dominant decoherence effect, rather than information exchange between tracer and gas particles. While a coherent superposition of two wave packets with different mean positions quickly turns into a mixed state, it is demonstrated that such superpositions of different momenta are robust to phase averaging, until the two wave packets acquire a different position due to the different velocity of each wave packet.

  5. Tracer Cycles and Water Ages in Heterogeneous Catchments and Aquifers

    NASA Astrophysics Data System (ADS)

    Kirchner, J. W.; Jasechko, S.

    2015-12-01

    Estimates of catchment mean transit times are often based on seasonal cycles of stable isotope tracers in precipitation and streamflow. In many cases these transit time estimates are derived directly from sine-wave fitting to the observed seasonal isotope cycles. Broadly similar results are also obtained from time-domain convolutions or explicit tracer modeling, because here too the dominant tracer signal that these techniques seek to match is the seasonal isotopic cycle. Here I use simple benchmark tests to show that estimates of mean transit times based on seasonal tracer cycles will typically be wrong by several hundred percent, when applied to catchments with realistic degrees of spatial heterogeneity. This aggregation bias arises from the strong nonlinearity in the relationship between tracer cycle amplitude and mean travel time. A similar bias arises in estimates of mean transit times in nonstationary catchments. Since typical real-world catchments are both spatially heterogeneous and nonstationary, this analysis poses a fundamental challenge to tracer-based estimates of mean transit times. I propose an alternative storage metric, the fraction of "young water" in streamflow, defined as the fraction of runoff with transit times of less than roughly 0.2 years. I show that young water fractions are virtually free of aggregation bias; that is, they can be accurately estimated from tracer cycles in highly heterogeneous mixtures of subcatchments with strongly contrasting transit time distributions. They can also be reliably estimated in strongly nonstationary catchments. Young water fractions can be estimated separately for individual flow regimes, allowing direct determination of how shifts in hydraulic regime alter the fraction of water reaching the stream by fast flowpaths. One can also estimate the chemical composition of idealized "young water" and "old water" end-members, using relationships between young water fractions and solute concentrations across

  6. Interpreting Multiple Environmental Tracer Data in a Perialpine Catchment

    NASA Astrophysics Data System (ADS)

    Onnis, G. A.; Althaus, R.; Klump, S.; Purtschert, R.; Kipfer, R.; Hendricks-Franssen, H.; Stauffer, F.; Kinzelbach, W.

    2008-12-01

    A case study for the environmental tracers Tritium, Helium-3 and Krypton-85 in a small sand-gravel aquifer catchment in Northern Switzerland is presented. The groundwater flow is determined by means of Stochastic Inverse Modelling, using available transient hydraulic head and transmissivity (T) data to calibrate the transmissivity field with the Sequential Self-Calibration Technique as implemented in the code INVERTO. The evaluation of the aquifer recharge and its discharge via natural springs is independently performed and confirmed through comparison of simulated and observed head after the inversion procedure. A number of equally-likely transmissivity field realizations honoring both transmissivity and transient head measurements is generated, establishing the basis for environmental tracer transport modeling. The impact of the spatially-variable, thick unsaturated zone (>10 m) on tracer transport is accounted for by means of a numerical solution to the vertical advection-dispersion equation. Starting from the measured tracer concentrations in the atmosphere, the input history to the saturated zone is reconstructed for different groundwater table depths. Environmental tracer transport in the saturated zone is investigated for each calibrated T -realization. The transport simulation results are in general fair for all tracers and can well reproduce the tracer data at most observation locations, with a small uncertainty bandwidth related to the T -parameter. Ad-hoc zonation of transport parameters (vadose zone gas-phase tortuosity and saturated porosity) can help in achieving a simultaneous match of the tracer data at all locations. However, the model can account for only 20% of the amplitude of the high-frequency oscillations in Krypton-85 concentrations observed at one pumping station. Short term variations of the recharge rate and of the actual pumping rate can account for a further 10% each to the Krypton-85 concentration fluctuations amplitudes. The origin of

  7. Use of dye tracers to collect hydrologic data in Oregon

    USGS Publications Warehouse

    Harris, D.D.; Sanderson, R.B.

    1968-01-01

    Dye tracers have been used in Oregon in the Collection of hydrologic data on 2,350 miles of stream channels in the Long Tom, Umpqua, Willmette, and John Day River basins, and in the Carmen‐Smith power tunnel. These investigations demonstrated the usefulness, of dye tracers for determining: (1) estimates of traveltimes and travel rates of water, (2) discharge where standard methods of measuring are not applicable, and (3) dispersion characteristics of streams. Illustrations are used to present the results of time‐of‐travel studies in simple, concise, and readily interpreted form. 

  8. Radioactive γ/β tracer to explore dangerous technogenic phenomena

    NASA Astrophysics Data System (ADS)

    Nagorsky, P. M.; Yakovleva, V. S.; Makarov, E. O.; Firstov, P. P.; Kondratyeva, A. G.; Stepanenko, A. A.

    2016-06-01

    A radioactive γ/β tracer to explore dangerous technogenic phenomena has been proposed: the ratio of the measured flux density of β- and γ-radiations in the surface layer of the atmosphere. The time dependence analysis of the ratio of β- and γ-pulse count rate has been carried out. A significant increase of the γ/β ratio was recorded under the cyclone passing through Japan (Fukushima) to Kamchatka. The proposed γ/β tracer can be a very sensitive indicator of nonstationary processes related to hazardous natural and technogenic phenomena.

  9. Development of luminescent bacteria as tracers for geological reservoir characterization

    SciTech Connect

    King, J.W.

    1991-01-01

    This research project resulted from recognizing the problem of being unable to accurately distinguish communication between wells in producing oil zones which may or may not be continuous. Such a determination is necessary when considering Enhanced Oil Recovery (EOR) whether it is water flooding, carbon dioxide, or other methods which increase the sweep efficiency. Various kinds of chemical tracers are available, but they are expensive and many might be considered hazardous for underground aquifers. Other biological tracers are available, but have never been developed for oil reservoir conditions. Bioluminescent bacteria seemed an obvious candidate because they thrive in saline waters (usually 3% salt) which have been contaminated by oil spills.

  10. Radiologic atlas of pulmonary abnormalities in children

    SciTech Connect

    Singleton, E.B.; Wagner, M.L.; Dutton, R.V.

    1988-01-01

    This book is an atlas about thoracic abnormalities in infants and children. The authors include computed tomographic, digital subtraction angiographic, ultrasonographic, and a few magnetic resonance (MR) images. They recognize and discuss how changes in the medical treatment of premature infants and the management of infection and pediatric tumors have altered some of the appearances and considerations in these diseases. Oriented toward all aspects of pulmonary abnormalities, the book starts with radiographic techniques and then discusses the normal chest, the newborn, infections, tumors, and pulmonary vascular diseases. There is comprehensive treatment of mediastinal abnormalities and a discussion of airway abnormalities.

  11. Increased 18F-FDG Uptake in Multiple Muscles in a Patient With Violent Cough.

    PubMed

    Wang, Yu; Shao, Fuqiang; Zhang, Li; Luo, Xiufang; Chen, Yue

    2017-03-31

    Increased muscular FDG uptake could be due to various causes. Detailed analysis combined with history might be helpful for image interpretation. We present FDG PET/CT findings of a 69-year-old woman with lung cancer. The images demonstrated intense FDG uptake in multiple muscles, likely due to cough before the PET/CT study. To relieve the patient's cough, codeine was administrated. The second F-FDG PET/CT was performed 2 days later. The images showed that the abnormal muscular activity had become decreased, which was slightly lower than hepatic activity.

  12. Incidental thyroid 99mTc-MDP uptake in a patient affected by differentiated thyroid cancer.

    PubMed

    Albano, Domenico; Magri, Gian Carlo; Treglia, Giorgio; Bertagna, Francesco

    2016-01-01

    We report a case of incidental uptake of 99mTc-methylene diphosphonate in the thyroid in a 62-year-old female with a history of breast cancer treated with quadrantectomy, chemotherapy and radiotherapy, who underwent total-body-bone scintigraphy during follow up. Planar scintigraphy was followed by neck SPECT-CT that demonstrated an area of increased tracer uptake in the neck at the left lobe of the thyroid. Neck ultrasonography showed a nodule corresponding to SPECT-CT finding and the ultrasound-guided fine needle aspiration documented the presence of papillary carcinoma. The patient underwent total thyroidectomy and ipsilateral lymphadenectomy; histological examination confirmed the presence of a papillary carcinoma and the patient underwent ablation therapy with iodine-131.

  13. Experiments to Evaluate and Implement Passive Tracer Gas Methods to Measure Ventilation Rates in Homes

    SciTech Connect

    Lunden, Melissa; Faulkner, David; Heredia, Elizabeth; Cohn, Sebastian; Dickerhoff, Darryl; Noris, Federico; Logue, Jennifer; Hotchi, Toshifumi; Singer, Brett; Sherman, Max H.

    2012-10-01

    This report documents experiments performed in three homes to assess the methodology used to determine air exchange rates using passive tracer techniques. The experiments used four different tracer gases emitted simultaneously but implemented with different spatial coverage in the home. Two different tracer gas sampling methods were used. The results characterize the factors of the execution and analysis of the passive tracer technique that affect the uncertainty in the calculated air exchange rates. These factors include uncertainties in tracer gas emission rates, differences in measured concentrations for different tracer gases, temporal and spatial variability of the concentrations, the comparison between different gas sampling methods, and the effect of different ventilation conditions.

  14. Study of stability zone influences and tracer patterns from the 1987 ANATEX (Across North America Tracer Experiment) experiment

    SciTech Connect

    Porch, W.M.; Gifford, F.A.; Hoard, D.E.

    1988-01-01

    In this paper, we will show preliminary results which appear to connect much of the hit and miss behavior of the surface tracer samples to large scale stability zones 100 to 1000 km wide. With these wintertime stability effects in mind, we have done the best we can to characterize the observed overall tracer patterns as well as individual tracer releases. This type of survey information is important to numerical model development. Diagnostic models often have difficulty reproducing surface plume concentrations where transport over stable layers have occurred. Prognostic models can, in theory, model effects of strong stable layers. However, these models would have great difficulty predicting large scale stable regions such as those observed during ANATEX. Also, though these models have ways of budging in synoptic wind fields, temperature observations are presently ignored. This is because if both wind and temperature observations are forced too strongly into the model, conflicting results may be produced. 12 refs., 5 figs.

  15. Ferrous iron uptake in Cryptococcus neoformans.

    PubMed

    Jacobson, E S; Goodner, A P; Nyhus, K J

    1998-09-01

    Previous studies have implicated ferric reduction in the iron uptake pathway of the opportunistic pathogen Cryptococcus neoformans. Here we studied iron uptake directly, using 55Fe in the presence of reductants. Uptake was linear with respect to time and number of yeast cells. The plot of uptake versus concentration exhibited a steep rise up to about 1 microM, a plateau between 1 and 25 microM, and a second steep rise above 25 microM, consistent with high- and low-affinity uptake systems. A Km for high-affinity uptake was estimated to be 0.6 microM Fe(II); 1 microM was used for standardized uptake assays. At this concentration, the uptake rate was 110 +/- 3 pmol/10(6) cells/h. Iron repletion (15 microM) and copper starvation drastically decreased high-affinity iron uptake. Incubation at 0 degreesC or in the presence of 2 mM KCN abolished high-affinity iron uptake, suggesting that uptake requires metabolic energy. When exogenous reducing agents were not supplied and the culture was washed free of secreted reductants, uptake was reduced by 46%; the remaining uptake activity presumably was dependent upon the cell membrane ferric reductase. Further decreases in free Fe(II) levels achieved by trapping with bathophenanthroline disulfonate or reoxidizing with potassium nitrosodisulfonate reduced iron uptake very drastically, suggesting that it is the Fe(II) species which is transported by the high-affinity transporter. The uptake of Fe was stimulated two- to threefold by deferoxamine, but this increment could be abolished by copper starvation or inhibition of the ferric reductase by Pt, indicating that Fe solubilized by this molecule also entered the reductive iron uptake pathway.

  16. An Abnormal Psychology Community Based Interview Assignment

    ERIC Educational Resources Information Center

    White, Geoffry D.

    1977-01-01

    A course option in abnormal psychology involves students in interviewing and observing the activities of individuals in the off-campus community who are concerned with some aspect of abnormal psychology. The technique generates student interest in the field when they interview people about topics such as drug abuse, transsexualism, and abuse of…

  17. Immune Abnormalities in Patients with Autism.

    ERIC Educational Resources Information Center

    Warren, Reed P.; And Others

    1986-01-01

    A study of 31 autistic patients (3-28 years old) has revealed several immune-system abnormalities, including decreased numbers of T lymphocytes and an altered ratio of helper-to-suppressor T cells. Immune-system abnormalities may be directly related to underlying biologic processes of autism or an indirect reflection of the actual pathologic…

  18. Nail abnormalities in patients with vitiligo*

    PubMed Central

    Topal, Ilteris Oguz; Gungor, Sule; Kocaturk, Ozgur Emek; Duman, Hatice; Durmuscan, Mustafa

    2016-01-01

    Background Vitiligo is an acquired pigmentary skin disorder affecting 0.1-4% of the general population. The nails may be affected in patients with an autoimmune disease such as psoriasis, and in those with alopecia areata. It has been suggested that nail abnormalities should be apparent in vitiligo patients. Objective We sought to document the frequency and clinical presentation of nail abnormalities in vitiligo patients compared to healthy volunteers. We also examined the correlations between nail abnormalities and various clinical parameters. Methods This study included 100 vitiligo patients and 100 healthy subjects. Full medical histories were collected from the subjects, who underwent thorough general and nail examinations. All nail changes were noted. In the event of clinical suspicion of a fungal infection, additional mycological investigations were performed. Results Nail abnormalities were more prevalent in the patients (78%) than in the controls (55%) (p=0.001). Longitudinal ridging was the most common finding (42%), followed by (in descending order): leukonychia, an absent lunula, onycholysis, nail bed pallor, onychomycosis, splinter hemorrhage and nail plate thinning. The frequency of longitudinal ridging was significantly higher in patients than in controls (p<0.001). Conclusions Nail abnormalities were more prevalent in vitiligo patients than in controls. Systematic examination of the nails in such patients is useful because nail abnormalities are frequent. However, the causes of such abnormalities require further study. Longitudinal ridging and leukonychia were the most common abnormalities observed in this study. PMID:27579738

  19. Microfluidics: a groundbreaking technology for PET tracer production?

    PubMed

    Rensch, Christian; Jackson, Alexander; Lindner, Simon; Salvamoser, Ruben; Samper, Victor; Riese, Stefan; Bartenstein, Peter; Wängler, Carmen; Wängler, Björn

    2013-07-05

    Application of microfluidics to Positron Emission Tomography (PET) tracer synthesis has attracted increasing interest within the last decade. The technical advantages of microfluidics, in particular the high surface to volume ratio and resulting fast thermal heating and cooling rates of reagents can lead to reduced reaction times, increased synthesis yields and reduced by-products. In addition automated reaction optimization, reduced consumption of expensive reagents and a path towards a reduced system footprint have been successfully demonstrated. The processing of radioactivity levels required for routine production, use of microfluidic-produced PET tracer doses in preclinical and clinical imaging as well as feasibility studies on autoradiolytic decomposition have all given promising results. However, the number of microfluidic synthesizers utilized for commercial routine production of PET tracers is very limited. This study reviews the state of the art in microfluidic PET tracer synthesis, highlighting critical design aspects, strengths, weaknesses and presenting several characteristics of the diverse PET market space which are thought to have a significant impact on research, development and engineering of microfluidic devices in this field. Furthermore, the topics of batch- and single-dose production, cyclotron to quality control integration as well as centralized versus de-centralized market distribution models are addressed.

  20. A Tracer Study of Lebanese Upper Secondary School Students

    ERIC Educational Resources Information Center

    Vlaardingerbroek, Barend; Dallal, Kamel; Rizkallah, George; Rabah, Jihan

    2007-01-01

    This paper presents data arising from a tracer study of 90 terminating Beirut upper secondary school students. Nearly all the students intended to transit to university, about half of them to science and technology programmes, and subsequently did so. Median anticipated earnings upon graduation were realistic, but a lack of information or guidance…

  1. Studies of thunderstorm transport processes with aircraft using tracer techniques

    SciTech Connect

    Detwiler, A.G.; Smith, P.L.; Stith, J.L.

    1996-10-01

    Instrumented aircraft can provide in situ measurements of winds and turbulence useful for studying transport and dispersion in clouds. Using inert artificial gases as tracers, and fast response analyzers on aircraft, time-resolved observations of transport and dispersion have been obtained. Examples are shown of these types of observations in and around cumulus and cumulonimbus clouds. 23 refs., 6 figs.

  2. Bridging the gaps in 18F PET tracer development

    NASA Astrophysics Data System (ADS)

    Campbell, Michael G.; Mercier, Joel; Genicot, Christophe; Gouverneur, Véronique; Hooker, Jacob M.; Ritter, Tobias

    2017-01-01

    As compared to the drug discovery process, the development of new 18F PET tracers lacks a well-established pipeline that advances compounds from academic research to candidacy for (pre)clinical imaging. In order to bridge the gaps between methodological advances and clinical success, we must rethink the development process from training to implementation.

  3. TRACER DISPERSION STUDIES FOR HYDRAULIC CHARACTERIZATION OF PIPES

    EPA Science Inventory

    A series of experiments were conducted at the U. S. Environmental Protection Agency (EPA) Test & Evaluation (T&E) Facility in Cincinnati, Ohio, to quantify longitudinal dispersion of a sodium fluoride tracer in polyvinyl chloride (PVC) pipe and ductile iron pipe under laminar, tr...

  4. Noninvasive Imaging of Tracer Experiments in a Soil Column

    NASA Astrophysics Data System (ADS)

    Jelinkova, V.; Pohlmeier, A.; van Dusschoten, D.; Vereecken, H.; Cislerova, M.

    2008-12-01

    A set of tracer-infiltration experiments on soil columns by means of magnetic resonance imaging (MRI) was performed. Computed tomography (CT) was applied in order to map the spatial distribution of porous media, namely the local densities and porosities, and their variation within the soil sample under test. The CT visualisation was done in order to trace disturbances in the structure as a possible source of preferential flow. By means of MRI the flow paths during the infiltration experiment were visualized using a tracer pulse containing Ni(NO3)2 in a concentration of 0.05 mol/litre. The pulse was added under hydraulic steady state conditions. The tracer motion was monitored through its effect on the signal relaxation of 1H using a 7 Tesla vertical magnet system equipped with a 40 mm RF probe. The boundary condition at the top of the soil columns was maintained using a dripping system connected to a HPLC pump with flow rate set to 0.5 ml/min. Free outflow was used as the bottom boundary condition. The vertical component of the local velocity value was calculated after the experiment. Small disturbances in the tracer front observed during the break-through could be related to the preferential flow phenomena in combination with the air bubble entrapment. This research has been supported by research project SP/2e7/229/07 and DBU - Deutsche Bundesstiftung Umwelt.

  5. Granulation of Pyrotechnic Tracer Composition R284T

    DTIC Science & Technology

    1988-03-01

    Properties of Materials used in Pyrotechnic Compositions (1963). Engineering Design Handbook - Military Pyrotechnic Series Part 3. AMPC 706-187. 4...Ml Cartridge AMPC 706-185 APPLICATION: Main Tracer Charge TM9-1910 Ellern STORAGE: NATO DoD McIntyre Hazards Class (Q/D 1.1 7 Cabbaje & Ewing

  6. Tracer Studies In A Laboratory Beach Subjected To Waves

    EPA Science Inventory

    This work investigated the washout of dissolved nutrients from beaches due to waves by conducting tracer studies in a laboratory beach facility. The effects of waves were studied in the case where the beach was subjected to the tide, and that in which no tidal action was present...

  7. 45. BUILDING NO. 462, CHEMISTRY LAB (FORMERLY TRACER LOADING BUILDING), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    45. BUILDING NO. 462, CHEMISTRY LAB (FORMERLY TRACER LOADING BUILDING), VIEW LOOKING SOUTHEAST AT WEST SIDE. BUILDING NO. 462-B, GENERAL PURPOSE MAGAZINE, AT LEFT. - Picatinny Arsenal, 400 Area, Gun Bag Loading District, State Route 15 near I-80, Dover, Morris County, NJ

  8. Correlative microscopy of densely labeled projection neurons using neural tracers.

    PubMed

    Oberti, Daniele; Kirschmann, Moritz A; Hahnloser, Richard H R

    2010-01-01

    Three-dimensional morphological information about neural microcircuits is of high interest in neuroscience, but acquiring this information remains challenging. A promising new correlative technique for brain imaging is array tomography (Micheva and Smith, 2007), in which series of ultrathin brain sections are treated with fluorescent antibodies against neurotransmitters and synaptic proteins. Treated sections are repeatedly imaged in the fluorescence light microscope (FLM) and then in the electron microscope (EM). We explore a similar correlative imaging technique in which we differentially label distinct populations of projection neurons, the key routers of electrical signals in the brain. In songbirds, projection neurons can easily be labeled using neural tracers, because the vocal control areas are segregated into separate nuclei. We inject tracers into areas afferent and efferent to the main premotor area for vocal production, HVC, to retrogradely and anterogradely label different classes of projection neurons. We optimize tissue preparation protocols to achieve high fluorescence contrast in the FLM and good ultrastructure in the EM (using osmium tetroxide). Although tracer fluorescence is lost during EM preparation, we localize the tracer molecules after fixation and embedding by using fluorescent antibodies against them. We detect signals mainly in somata and dendrites, allowing us to classify synapses within a single ultrathin section as belonging to a particular type of projection neuron. The use of our method will be to provide statistical information about connectivity among different neuron classes, and to elucidate how signals in the brain are processed and routed among different areas.

  9. Unit vent airflow measurements using a tracer gas technique

    SciTech Connect

    Adams, D.G.; Lagus, P.L.; Fleming, K.M.

    1997-08-01

    An alternative method for assessing flowrates that does not depend on point measurements of air flow velocity is the constant tracer injection technique. In this method one injects a tracer gas at a constant rate into a duct and measures the resulting concentration downstream of the injection point. A simple equation derived from the conservation of mass allows calculation of the flowrate at the point of injection. Flowrate data obtained using both a pitot tube and a flow measuring station were compared with tracer gas flowrate measurements in the unit vent duct at the Callaway Nuclear Station during late 1995 and early 1996. These data are presented and discussed with an eye toward obtaining precise flowrate data for release rate calculations. The advantages and disadvantages of the technique are also described. In those test situations for which many flowrate combinations are required, or in large area ducts, a tracer flowrate determination requires fewer man-hours than does a conventional traverse-based technique and does not require knowledge of the duct area. 6 refs., 10 figs., 6 tabs.

  10. Simple Spreadsheet Models For Interpretation Of Fractured Media Tracer Tests

    EPA Science Inventory

    An analysis of a gas-phase partitioning tracer test conducted through fractured media is discussed within this paper. The analysis employed matching eight simple mathematical models to the experimental data to determine transport parameters. All of the models tested; two porous...

  11. Diagnostic Implications of the Reactivity of Fluorescence Tracers

    SciTech Connect

    Sick, V; Westbrook, C

    2008-07-14

    Measurements of fuel concentration distributions with planar laser induced fluorescence of tracer molecules that are added to a base fuel are commonly used in combustion research and development. It usually is assumed that the tracer concentration follows the parent fuel concentration if physical properties such as those determining evaporation are matched. As an example to address this general issue a computational study of combustion of biacetyl/iso-octane mixtures was performed to investigate how well the concentration of biacetyl represents the concentration of iso-octane. For premixed mixture conditions with flame propagation the spatial concentration profiles of the two species in the flame front are separated by 110 {micro}m at 1 bar and by 11 {micro}m at 10 bar. For practical applications this spatial separation is insignificantly small. However, for conditions that mimic ignition and combustion in diesel and HCCI-like operation the differences in tracer and fuel concentration can be significant, exceeding hundreds of percent. At low initial temperature biacetyl was found to be more stable whereas at higher temperature (>1000K) iso-octane is more stable. Similar findings were obtained for a multi-component fuel comprised of iso-octane, n-heptane, methylcyclohexane, and toluene. It may be assumed that similar differences can exist for other tracer/fuel combinations. Caution has therefore to be applied when interpreting PLIF measurements in homogeneous reaction conditions such as in HCCI engine studies.

  12. Tracer Modeling with the Hybrid Coordinates Ocean Model (hycom)

    NASA Astrophysics Data System (ADS)

    Garraffo, Z. D.; Kim, H.; Li, B.; Mehra, A.; Rivin, I.; Spindler, T.; Tolman, H. L.

    2012-12-01

    A series of tracer simulations have been started at NCEP/NWS aiming to a variety of applications, from dispersion of contaminants in estimations motivated by the Japanese nuclear accident near Fukushima, to nutrient estimations. The tracer capabilities of HYCOM are used, in regional domains, nested to daily nowcast/forecast fields from 1/12 HYCOM (RTOFS-Global) model output. A Fukushima Cs-137 simulation is now run in operational mode (RTOFS_ET). The simulation was initialized at the time of the Fukushima nuclear accident, and includes atmospheric deposition of Cs-137 and coastal discharge from a high resolution coastal model (ROMS done at NOAA/NOS). Almost all tracer moved offshore before the end of the first year after the accident. The tracer initially deposited in the Pacific ocean through the atmosphere slowly moves eastward and to deeper waters following the 3D ocean circulation. A series of simulations were started for nutrient estimations in the Gulf Stream and Mid Atlantic Bight region. Initially the capabilities implemented in HYCOM are used. The work aims to monitoring nutrients in the chosen region. Work is done in collaboration with Victoria Coles of U. Maryland.

  13. Sediment tracers in water erosion studies: Current approaches and challenges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The interest in the use of sediment tracers as a complementary tool to traditional water soil erosion or deposition measurements or assessment has increased due to the additional information they may provide such as sediment source identification and tracking of sediment movement over the landscape ...

  14. How to Program a Domain Independent Tracer for Explanations

    ERIC Educational Resources Information Center

    Ishizaka, Alessio; Lusti, Markus

    2006-01-01

    Explanations are essential in the teaching process. Tracers are one possibility to provide students with explanations in an intelligent tutoring system. Their development can be divided into four steps: (a) the definition of the trace model; (b) the extraction of the information from this model; (c) the analysis and abstraction of the extracted…

  15. Study of North Atlantic ventilation using transient tracers. Doctoral Thesis

    SciTech Connect

    Doney, S.C.

    1991-08-01

    Tritium, (3)He, and chlorofluorocarbon distributions in the North Atlantic provide constraints on the ventilation time-scales for the thermocline and abyssal water. A new model function based on a factor analysis of the WMO/IAEA precipitation data set is developed for predicting the spatial and temporal patterns of bomb-tritium in precipitation. Model atmospheric and advective tritium inputs to the North Atlantic are compared with the observed bomb-tritium inventories calculated from the 1972 GEOSECS and 1981-1983 TTO data sets. The observed growth of bomb-tritium levels in the deep North Atlantic are used, along with the tracer gradients ((3)H and (3)He) in the Deep Western Boundary Current, to estimate abyssal ventilation rates and boundary current recirculation. The surface boundary conditions for different transient tracers are found to profoundly effect thermocline ventilation rates estimates. Tracers that equilibrate rapidly with the atmosphere, such as (3)He and the CFCs, have faster apparent ventilation rates and are more appropriate for estimating oxygen utilization rates than tracers that are reset slowly in the surface ocean (e.g. (3)H and (14)C). The chlorofluorocarbon data for a new section in the eastern North Atlantic are presented and used to illustrate the ventilation time-scales for the major water masses in the region. (Copyright (c) Scott C. Doney, 1991.)

  16. Development of Kinetic Interface Sensitive Tracers (KIS-Tracer) for Supercritical Carbon Dioxide Injections into Deep Saline Aquifers

    NASA Astrophysics Data System (ADS)

    Schaffer, M.; Maier, F.; Licha, T.; Sauter, M.

    2012-04-01

    The storage of captured CO2 into geological formations is recently one of the most promising technologies to mitigate anthropogenic greenhouse gas emissions into the earth's atmosphere. Deep saline aquifers are considered as the most potential sequestration sites of CO2 due to their huge storage capacities of several thousand Gt. Ongoing research deals mainly with the investigation of relevant physico-chemical processes, the fate of CO2 and the risk assessment during and after supercritical CO2 (scCO2) injections. The occurring processes at the interface between injected scCO2 and formation brine play a major role to evaluate the fate and behavior of scCO2 in the reservoir. This is because the interface represents a reactive zone where numerous physico-chemical processes like dissolution of scCO2 in water as well as dissolution and precipitation of minerals take place. In most cases it is desired to maximize the interface size to increase the storage efficiency. Therefore, knowledge on interface size and dynamics would allow the observation of plume spreading and the detection of mixing or fingering effects. In order to gain this information innovative tracers are necessary which are able to quantify the temporal and spatial development of scCO2/water interfaces. As a result, it may be possible to assess the storage efficiency and to optimize subsequent injections. Up to now, such time-dependent tracers for reservoir studies are not available and limited to equilibrium tracers (known as partitioning and interfacial tracers, respectively). Therefore, novel reactive tracers (KIS-Tracers) are developed to overcome this gap. The idea is to find suitable molecules which allow the implementation of a defined chemical reaction at the interface. Due to the known kinetic constants the change of interface size can be characterized over time. The new tracer is injected together with the supercritical CO2 (scCO2) into a deep saline aquifer. Afterwards, the tracer adsorbs at

  17. Synthesis and characterization of environmentally friendly fluorescent particle tracers

    NASA Astrophysics Data System (ADS)

    Tauro, Flavia; Porfiri, Maurizio; Rapiti, Emiliano; Grimaldi, Salvatore

    2013-04-01

    Tracers are widely used in experimental fluid mechanics and hydrology to investigate complex flows and water cycle processes. Commonly used tracers include dyes, artificial tracers, naturally occurring isotopes and chemicals, microorganisms, and DNA-based systems. Tracers should be characterized by low detection limits and high accuracy in following water paths and flow structures. For natural studies, tracers are also expected to be nontoxic and with low sorption affinity to natural substrates to minimize losses in the environment. In this context, while isotopes are completely natural, their use in field studies is limited by their ubiquity and, therefore, by the high uncertainty in data processing methodologies. Further, the use of dyes and artificial tracers can be hampered by extremely low detection limits due to dilution in natural streams and microorganisms, while DNA-based system may require physical sampling and time-consuming functionalization and detection procedures. In this work, we present the synthesis and characterization of fluorescent beads incorporating an eco-compatible fluorophore for environmental and laboratory applications. The particles are synthesized from natural beeswax through an inexpensive thermal procedure and can be engineered to present variable densities and diameters. A thorough characterization of their surface morphology at the nanoscale, crystal structure and size, chemical composition, and dye incorporation into the beeswax matrix is described by using a wide array of microscopy techniques. In addition, the particle fluorescence response is studied by performing excitation and emission scans on melted beeswax bead samples. The feasibility of using the synthesized particles in environmental settings is assessed through the design of ad-hoc weathering agent experiments where the beads are exposed to high energy radiation and hot water. Further, a proof of concept test is described to understand the particles' potential as a

  18. Assessment of Halon-1301 as a groundwater age tracer

    NASA Astrophysics Data System (ADS)

    Beyer, M.; van der Raaij, R.; Morgenstern, U.; Jackson, B.

    2015-06-01

    Groundwater dating is an important tool to assess groundwater resources in regards to their dynamics, i.e. direction and timescale of groundwater flow and recharge, contamination risks and manage remediation. To infer groundwater age information, a combination of different environmental tracers, such as tritium and SF6, are commonly used. However, ambiguous age interpretations are often faced, due to a limited set of available tracers and their individual restricted application ranges. For more robust groundwater dating multiple tracers need to be applied complementarily (or other characterisation methods need to be used to complement tracer information). It is important that additional, groundwater age tracers are found to ensure robust groundwater dating in future. We have recently suggested that Halon-1301, a water soluble and entirely anthropogenic gaseous substance, may be a promising candidate, but its behaviour in water and suitability as a groundwater age tracer had not yet been assessed in detail. In this study, we determined Halon-1301 and inferred age information in 17 New Zealand groundwater samples and various modern (river) water samples. The samples were simultaneously analysed for Halon-1301 and SF6, which allowed for identification of issues such as contamination of the water with modern air during sampling. All analysed groundwater sites had also been previously dated with tritium, CFC-12, CFC-11 and SF6, and exhibited mean residence times ranging from modern (close to 0 years) to over 100 years. The investigated groundwater samples ranged from oxic to highly anoxic. All samples with available CFC data were degraded and/or contaminated in one or both of CFC-11 and CFC-12. This allowed us to make a first attempt of assessing the conservativeness of Halon-1301 in water, in terms of presence of local sources and its sensitivity towards degradation, which could affect the suitability of Halon-1301 as groundwater age tracer. Overall we found Halon-1301

  19. Can transcutaneous recordings detect gastric electrical abnormalities?

    PubMed Central

    Familoni, B O; Bowes, K L; Kingma, Y J; Cote, K R

    1991-01-01

    The ability of transcutaneous recordings of gastric electrical activity to detect gastric electrical abnormalities was determined by simultaneous measurements of gastric electrical activity with surgically implanted serosal electrodes and cutaneous electrodes in six patients undergoing abdominal operations. Transient abnormalities in gastric electrical activity were seen in five of the six patients during the postoperative period. Recognition of normal gastric electrical activity by visual analysis was possible 67% of the time and with computer analysis 95% of the time. Ninety four per cent of abnormalities in frequency were detected by visual analysis and 93.7% by computer analysis. Abnormalities involving a loss of coupling, however, were not recognised by transcutaneous recordings. Transcutaneous recordings of gastric electrical activity assessed by computer analysis can usually recognise normal gastric electrical activity and tachygastria. Current techniques, however, are unable to detect abnormalities in electrical coupling. PMID:1864531

  20. Thyroid uptake of (/sup 99m/Tc) pertechnetate during in vivo RBC labeling: incidental diagnosis of hypothyroidism

    SciTech Connect

    Holmes, K.A.; Ponto, J.A.

    1981-09-01

    Increased thyroid activity was incidentally observed during an in vivo labeled Tc-99m blood pool scan and subsequent evaluation resulted in a diagnosis of hypothyroidism. Alternate explanations of abnormal thyroid uptake on in vivo labeled blood pool scans were considered and are discussed briefly.

  1. Docosahexaenoic acid affects arachidonic acid uptake in megakaryocytes

    SciTech Connect

    Schick, P.K.; Webster, P.

    1987-05-01

    Dietary omega 3 fatty acids are thought to prevent atherosclerosis, possibly by modifying platelet (PT) function and arachidonic acid (20:4) metabolism. The study was designed to determine whether omega 3 fatty acids primarily affect 20:4 metabolism in megakaryocytes (MK), bone marrow precursors of PT, rather than in circulating PT. MK and PT were isolated from guinea pigs and incubated with (/sup 14/C)-20:4 (0.13uM). Docosahexaenoic acid (22:6) is a major omega 3 fatty acid in marine oils. The incubation of MK with 22:6 (0.1, 1.0 uM) resulted in the decrease of incorporation of (/sup 14/C)-20:4 into total MK phospholipids, 16% and 41% respectively. Alpha-linolenic acid (18:3), a major omega 3 fatty acid present in American diets, had no effect on 20:4 uptake in MK. 22:6 primarily affected the uptake of (/sup 14/C)-20:4 into phosphatidylethanolamine (PE) and phosphatidylserine (PS) in MK. In MK, 22:6 (0.1, 1.0 uM) caused a decrease of incorporation of (/sup 14/C)-20:4 into PE, 21% and 55% respectively; a decrease into PS, 16% and 48% respectively; but only a decrease of 4% and 18%, respectively, into phosphatidylcholine; and a decrease of 3% and 21% into phosphatidylinositol 22:6 (3.0 uM) had no effect on the uptake of AA into PT phospholipids. The study shows that 22:6 has a selective effect on AA uptake in MK and that the acylation or transacylation of PE and PS are primarily affected. 22:6 and other marine omega 3 fatty acids appear to primarily affect megakaryocytes which may result in the production of platelets with abnormal content and compartmentalization of AA.

  2. 18F-FET and 18F-FCH uptake in human glioblastoma T98G cell lines

    PubMed Central

    Persico, Marco Giovanni; Buroni, Federica Eleonora; Pasi, Francesca; Aprile, Carlo; Nano, Rosanna; Hodolic, Marina

    2016-01-01

    Abstract Background Despite complex treatment of surgery, radiotherapy and chemotherapy, high grade gliomas often recur. Differentiation between post-treatment changes and recurrence is difficult. 18F-methyl-choline (18F-FCH) is frequently used in staging and detection of recurrent prostate cancer disease as well as some brain tumours; however accumulation in inflammatory tissue limits its specificity. The 18F-ethyl-tyrosine (18F-FET) shows a specific uptake in malignant cells, resulting from increased expression of amino acid transporters or diffusing through the disrupted blood-brain barrier. 18F-FET exhibits lower uptake in machrophages and other inflammatory cells. Aim of this study was to evaluate 18F-FCH and 18F-FET uptake by human glioblastoma T98G cells. Material and methods Human glioblastoma T98G or human dermal fibroblasts cells, seeded at a density to obtain 2 × 105 cells per flask when radioactive tracers were administered, grew adherent to the plastic surface at 37°C in 5% CO2 in complete medium. Equimolar amounts of radiopharmaceuticals were added to cells for different incubation times (20 to 120 minutes) for 18F-FCH and 18F-FET respectively. The cellular radiotracer uptake was determined with a gamma counter. All experiments were carried out in duplicate and repeated three times. The uptake measurements are expressed as the percentage of the administered dose of tracer per 2 × 105 cells. Data (expressed as mean values of % uptake of radiopharmaceuticals) were compared using parametric or non-parametric tests as appropriate. Differences were regarded as statistically significant when p<0.05. Results A significant uptake of 18F-FCH was seen in T98G cells at 60, 90 and 120 minutes. The percentage uptake of 18F-FET in comparison to 18F-FCH was lower by a factor of more than 3, with different kinetic curves.18F-FET showed a more rapid initial uptake up to 40 minutes and 18F-FCH showed a progressive rise reaching a maximum after 90 minutes

  3. Strontium Uptake by Cementitious Materials

    SciTech Connect

    Wieland,E.; Tits, J.; Kunz, D.; Dahn, R.

    2008-01-01

    Wet chemistry experiments and X-ray absorption fine structure (XAFS) measurements were carried out to investigate the immobilization of nonradioactive Sr and 85Sr in calcite-free and calcite-containing Portland cement. The partitioning of pristine Sr between hardened cement paste (HCP) and pore solution, and the uptake of 85Sr and nonradioactive Sr were investigated in batch-type sorption/desorption experiments. Sr uptake by HCP was found to be fast and nearly linear for both cements, indicating that differences in the compositions of the two cements have no influence on Sr binding. The partitioning of pristine Sr bound in the cement matrix and 85Sr between HCP and pore solution could be modeled in terms of a reversible sorption process using similar Kd values. These findings allow 85Sr uptake to be interpreted in terms of an isotopic exchange process with pristine Sr. Sr K-edge EXAFS measurements on Sr doped HCP and calcium silicate hydrate (C-S-H) samples reveal no significant differences in the local coordination environments of pristine Sr and Sr bound to the cement matrix upon sorption. The first coordination sphere consists of five to six oxygen atoms located at a distance of about 2.6 Angstroms, which corresponds to Sr-O distances in the hydration sphere of Sr2+ in alkaline solution. Sr binds to the cement matrix via two bridging oxygen atoms located at a distance of about 3.6 Angstroms. No further neighboring atoms could be detected, indicating that Sr is taken up as a partially hydrated species by HCP. Wet chemistry and spectroscopic data further indicate that Sr binding to C-S-H phases is likely to be the controlling uptake mechanism in the cement matrix, which allows Sr uptake by HCP to be predicted based on a Ca-Sr ion exchange model previously developed for Sr binding to C-S-H phases. The latter finding suggests that long-term predictions of Sr immobilization in the cementitious near field of repositories for radioactive waste can be based on a

  4. PET amyloid ligand [11C]PIB uptake shows predominantly striatal increase in variant Alzheimer's disease.

    PubMed

    Koivunen, J; Verkkoniemi, A; Aalto, S; Paetau, A; Ahonen, J-P; Viitanen, M; Någren, K; Rokka, J; Haaparanta, M; Kalimo, H; Rinne, J O

    2008-07-01

    Variant Alzheimer's disease (VarAD) with spastic paraparesis and presenile dementia is associated with certain mutations of the presenilin 1 (PS-1) gene, particularly those leading to deletion of exon 9 (PS-1Delta E9). VarAD is neuropathologically characterized by the presence of unusually large, Abeta42 positive, non-cored 'cotton wool' plaques (CWPs), also devoid of dystrophic neurites. The aim of the present study was to find out whether [(11)C]PIB would show increased uptake and serve as an in vivo biomarker of amyloid accumulation in VarAD. A further aim was to assess the correspondence of the [(11)C]PIB binding to the amount and type of Abeta deposits in another group of deceased VarAD patients' brains. We studied four patients with VarAD and eight healthy controls with PET using [(11)C]PIB as tracer. Parametric images were computed by calculating the region-to-cerebellum and region-to-pons ratio in each voxel over 60-90 min. Group differences in [(11)C]PIB uptake were analysed with automated region-of-interest (ROI) analysis. [(11)C]PIB uptake was compared to the immunohistochemically demonstrated deposition of Abeta in the brains of another group of four deceased VarAD patients. Patients with VarAD had significantly higher [(11)C] PIB uptake than the control group in the striatum (caudate nucleus and putamen), anterior and posterior cingulate gyrus, occipital cortex and thalamus. In the caudate and putamen [(11)C]PIB uptake, expressed as region-to-cerebellum ratio, was on the average 43% greater than the mean of the control group. The increases in the anterior (28%) and posterior (27%) cingulate gyrus, occipital cortex (21%) and thalamus (14%) were smaller. All VarAD patients showed this similar topographical pattern of increased [(11)C]PIB uptake. The results were essentially similar when the uptake was expressed as region-to-pons ratios. [(11)C]PIB imaging shows increased uptake in patients with VarAD especially in the striatum, and it can be used to

  5. Elevated Uptake of Plasma Macromolecules by Regions of Arterial Wall Predisposed to Plaque Instability in a Mouse Model

    PubMed Central

    Mohri, Zahra; Rowland, Ethan M.; Clarke, Lindsey A.; De Luca, Amalia; Peiffer, Véronique; Krams, Rob; Sherwin, Spencer J.; Weinberg, Peter D.

    2014-01-01

    Atherosclerosis may be triggered by an elevated net transport of lipid-carrying macromolecules from plasma into the arterial wall. We hypothesised that whether lesions are of the thin-cap fibroatheroma (TCFA) type or are less fatty and more fibrous depends on the degree of elevation of transport, with greater uptake leading to the former. We further hypothesised that the degree of elevation can depend on haemodynamic wall shear stress characteristics and nitric oxide synthesis. Placing a tapered cuff around the carotid artery of apolipoprotein E -/- mice modifies patterns of shear stress and eNOS expression, and triggers lesion development at the upstream and downstream cuff margins; upstream but not downstream lesions resemble the TCFA. We measured wall uptake of a macromolecular tracer in the carotid artery of C57bl/6 mice after cuff placement. Uptake was elevated in the regions that develop lesions in hyperlipidaemic mice and was significantly more elevated where plaques of the TCFA type develop. Computational simulations and effects of reversing the cuff orientation indicated a role for solid as well as fluid mechanical stresses. Inhibiting NO synthesis abolished the difference in uptake between the upstream and downstream sites. The data support the hypothesis that excessively elevated wall uptake of plasma macromolecules initiates the development of the TCFA, suggest that such uptake can result from solid and fluid mechanical stresses, and are consistent with a role for NO synthesis. Modification of wall transport properties might form the basis of novel methods for reducing plaque rupture. PMID:25531765

  6. FUNCTIONAL OVERLAP OF ROOT SYSTEMS IN AN OLD-GROWTH FOREST INFERRED FROM TRACER 15N UPTAKE

    EPA Science Inventory

    Belowground competition for nutrients and water is considered a key factor affecting spatial organization and productivity of individual stems within forest stands, yet there are few data describing the lateral extent and overlap of competing root systems. We quantified the func...

  7. Multimodal assessment of spatial distribution of drug-tracer uptake by brain tissue after intra-arterial injections

    NASA Astrophysics Data System (ADS)

    Singh-Moon, Rajinder; Chaudhuri, Durba; Wang, Mei; Straubinger, Robert; Bigio, Irving J.; Joshi, Shailendra

    2014-02-01

    It is challenging to track the rapid changes in drug concentrations after intra-arterial (IA) administration to elucidate the pharmacokinetics of this method of drug delivery. Traditional pharmacokinetic parameters (such as protein binding) that are highly relevant to intravenous (IV) administration do not seem to apply to IA injections. Regional drug delivery is affected by the biomechanics of drug injection, resting blood flow, and local tissue extraction. In-vivo and ex-vivo, optical methods for spatial mapping of drug deposition can assist in visualizing drug distributions and aid in the screening of potential drugs and carrier candidates. We present a multimodal approach for the assessment of drug distribution in postmortem tissue specimens using diffuse reflectance spectroscopy, multispectral imaging, and confocal microscopy and demonstrate feasibility of distinguishing route of administration advantages of liposome-dye conjugate delivery. The results of this study suggest that insight on drug dynamics gained by this aggregated approach can be used to help screen and/or optimize potential drug candidates and drug delivery protocols.

  8. Sediment tracers in water erosion studies: Current approaches and challenges

    NASA Astrophysics Data System (ADS)

    Guzmán, Gema; Quinton, John N.; Nearing, Mark A.; Mabit, Lionel; Giráldez, Juan V.; Gómez, José A.

    2013-04-01

    The quest for alternative methods of soil losses assessment, due to water erosion to complement and enhance existing methods has directed attention to the use of tracing approaches because of the additional information they provide, such as sediment source identification, tracking of sediment movement across the landscape at various temporal and spatial scales and soil erosion rates. For these reasons, the utility and robustness of sediment tracing approaches using a wide range of substances and soil properties have been evaluated in numerous studies. A comprehensive literature review on tracing approaches used in water erosion studies was carried out in June 2011 using the Web of Science database and as search terms in the title or as keywords: "erosion AND tracer" OR "sediment AND tracer" OR "sediment AND tracking". The search excluded reviews and tillage and/or wind erosion studies. Only studies that used tracers to make a determination of water erosion or sedimentation rates, or in some cases relative erosion contribution, were considered in this study, and were further refined by manually checking that the articles corresponded to experiments involving sediment studies using tracers, as defined within the context of this review. Five distinct groups of tracing approaches were identified: fallout radionuclides, rare earth elements, soil magnetism and magnetic substances, other tracers, and sediment fingerprinting techniques. This abstract presents a synthesis of the current approaches of each of the tracing techniques identified in assessing soil erosion and sediment redistribution and a summary with the commonalities and differences between the approaches and identifying research gaps and future trends.

  9. Quantifying Urban Water Subsidies with Hydrological Tracers of Domestic Water

    NASA Astrophysics Data System (ADS)

    Bain, D. J.; Sikora, M. T.; Wozniak, E.; Fisher, K. R.; Carr, J.; Elliott, E. M.

    2011-12-01

    Connections between urban hydrological systems and human water infrastructure are well established. Interactions between these systems occur at a wide range of scales, from large inter-basin transfers to individual leaking pipes. However, much of the interest in these connections arises from practical considerations, for example, substantially altered in-stream flow or the presence/absence of sewage in surface water systems. Less recognized is that in smaller urban catchments, daily water flux through human water distribution systems is often much larger than low flow surface water flux from the catchment. As infrastructure ages and cross-connections grow, transfers from the substantial human fluxes to the catchment will increasingly subsidize urban water budgets. Tools for quantifying the contribution of this subsidy to urban hydrological systems can clarify both practical questions for urban managers and our understanding of flow generation in catchments. Stream water chemistry from a multi-year sampling campaign in Nine Mile Run (Pittsburgh, PA) is used to examine potential hydrological tracers of human domestic water. In particular, we examine the use of fluoride added in precise quantities as a dental health supplement as a tracer of human domestic water (e.g., drinking and waste water). While fluoride is not necessarily a conservative tracer, equilibrium reactions governing fluoride solubility generally require substantially higher cationic concentrations than those observed in surface water chemistry. Further, during periods where human subsidies dominate (e.g., water line breaks or hydrant flushes discharging to the stream) fluoride concentrations generally approach the concentration added to domestic water. We use multiple modeling approaches to demonstrate the appropriateness of fluoride as a tracer, infer contributions of human domestic water to the hydrologic budget, and explore fluoride dynamics in the Nine Mile Run basin. A fluoride tracer is

  10. Dynamics of ellipsoidal tracers in swimming algal suspensions

    NASA Astrophysics Data System (ADS)

    Yang, Ou; Peng, Yi; Liu, Zhengyang; Tang, Chao; Xu, Xinliang; Cheng, Xiang

    2016-10-01

    Enhanced diffusion of passive tracers immersed in active fluids is a universal feature of active fluids and has been extensively studied in recent years. Similar to microrheology for equilibrium complex fluids, the unusual enhanced particle dynamics reveal intrinsic properties of active fluids. Nevertheless, previous studies have shown that the translational dynamics of spherical tracers are qualitatively similar, independent of whether active particles are pushers or pullers—the two fundamental classes of active fluids. Is it possible to distinguish pushers from pullers by simply imaging the dynamics of passive tracers? Here, we investigated the diffusion of isolated ellipsoids in algal C. reinhardtii suspensions—a model for puller-type active fluids. In combination with our previous results on pusher-type E. coli suspensions [Peng et al., Phys. Rev. Lett. 116, 068303 (2016), 10.1103/PhysRevLett.116.068303], we showed that the dynamics of asymmetric tracers show a profound difference in pushers and pullers due to their rotational degree of freedom. Although the laboratory-frame translation and rotation of ellipsoids are enhanced in both pushers and pullers, similar to spherical tracers, the anisotropic diffusion in the body frame of ellipsoids shows opposite trends in the two classes of active fluids. An ellipsoid diffuses fastest along its major axis when immersed in pullers, whereas it diffuses slowest along the major axis in pushers. This striking difference can be qualitatively explained using a simple hydrodynamic model. In addition, our study on algal suspensions reveals that the influence of the near-field advection of algal swimming flows on the translation and rotation of ellipsoids shows different ranges and strengths. Our work provides not only new insights into universal organizing principles of active fluids, but also a convenient tool for detecting the class of active particles.

  11. Isotope tracers in catchment hydrology: How far can we go?

    NASA Astrophysics Data System (ADS)

    McDonnell, J. J.

    2009-05-01

    The use of stable isotopes as tracers of water has fundamentally changed the way that we view catchment hydrology. Tracer-based mass balance mixing studies in the past decades have revealed that most of the water comprising the storm hydrograph (in humid areas) is dominated by pre-event water. Furthermore, using the convolution integral approach to long term isotopic time series, studies have revealed a wide range of streamwater residence times (focused mostly on baseflow), from months to decades, but with most on the order of 1-3 years. These findings have now matured to the point where such information is informing rainfall- runoff model testing. As a result, stable isotope tracers offer new and orthogonal data measures for rejecting model structures. Similarly, scaling relations detected in streamwater residence time data offer hope for a new pathway to understand and quantify multi-scale catchment response patterns. So how far can we go with stable isotope tracers in catchment hydrology? Here I offer some suggestions on new research avenues that capitalize on the use of laser spectrometers and how the resulting increased sample frequencies in time and space (with laser specs in the lab and in the field) may offer new hydrological insights. Examples are given that apply to ecohydrological studies in catchments to resolve how vegetation and streams appear to return different pools of water to the hydrosphere; virtual experiments with catchment models to assess the fundamental controls on catchment residence time distribution; multi-tracer approaches to streamwater residence time to reconcile the striking differences in residence time estimates between oxygen-18 and tritium; and labeled isotope additions at the plot, hillslope and catchment scale under controlled input conditions for resolving the age, origin and pathway of flow.

  12. Single-scan dual-tracer FLT+FDG PET tumor characterization

    NASA Astrophysics Data System (ADS)

    Kadrmas, Dan J.; Rust, Thomas C.; Hoffman, John M.

    2013-02-01

    Rapid multi-tracer PET aims to image two or more tracers in a single scan, simultaneously characterizing multiple aspects of physiology and function without the need for repeat imaging visits. Using dynamic imaging with staggered injections, constraints on the kinetic behavior of each tracer are applied to recover individual-tracer measures from the multi-tracer PET signal. The ability to rapidly and reliably image both 18F-fluorodeoxyglucose (FDG) and 18F-fluorothymidine (FLT) would provide complementary measures of tumor metabolism and proliferative activity, with important applications in guiding oncologic treatment decisions and assessing response. However, this tracer combination presents one of the most challenging dual-tracer signal-separation problems—both tracers have the same radioactive half-life, and the injection delay is short relative to the half-life and tracer kinetics. This work investigates techniques for single-scan dual-tracer FLT+FDG PET tumor imaging, characterizing the performance of recovering static and dynamic imaging measures for each tracer from dual-tracer datasets. Simulation studies were performed to characterize dual-tracer signal-separation performance for imaging protocols with both injection orders and injection delays of 10-60 min. Better performance was observed when FLT was administered first, and longer delays before administration of FDG provided more robust signal-separation and recovery of the single-tracer imaging measures. An injection delay of 30 min led to good recovery (R > 0.96) of static image values (e.g. SUV), Knet, and K1 as compared to values from separate, single-tracer time-activity curves. Recovery of higher order rate parameters (k2, k3) was less robust, indicating that information regarding these parameters was harder to recover in the presence of statistical noise and dual-tracer effects. Performance of the dual-tracer FLT(0 min)+FDG(32 min) technique was further evaluated using PET/CT imaging studies in

  13. The Humidity Dependence of N2O5 Uptake to Citric Acid Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Grzinic, G.; Bartels-Rausch, T.; Tuerler, A.; Ammann, M.

    2013-12-01

    Dinitrogen pentoxide is a significant reactive intermediate in the night time chemistry of nitrogen oxides. Depending on atmospheric conditions it can act either as a NO3 radical reservoir or as a major NOx sink by heterogeneous hydrolysis on aerosol surfaces. As such, it can influence tropospheric ozone production and therefore the oxidative capacity of the atmosphere. The heterogeneous loss of N2O5 to aerosol particles has remained uncertain, and reconciling lab and field data has demonstrated some gaps in our understanding of the detailed mechanism. We used the short-lived radioactive tracer 13N to study N2O5 uptake kinetics on aerosol particles in an aerosol flow reactor at ambient pressure, temperature and relative humidity. Citric acid, representing strongly oxidized polyfunctional organic compounds in atmospheric aerosols, has been chosen as a proxy due to its well established physical properties. Aerosol uptake measurements were performed with citric acid aerosols in a humidity range of 15-75 % RH, within which the uptake coefficient varies between about 0.001 and about 0.02. Taking into account the well established hygroscopic properties of citric acid, we interpret uptake in terms of disproportionation of N2O5 into nitrate ion and nitronium ion and reaction of the latter with liquid water.

  14. Uptake of carbon-11-methionine and fluorodeoxyglucose in non-Hodgkin's lymphoma: A PET study

    SciTech Connect

    Leskinen-Kallio, S.; Ruotsalainen, U.; Nagren, K.T.; Teraes, M.J.; Joensuu, H. )

    1991-06-01

    Uptake of L-(methyl-11C)methionine (11C-methionine) and (18F)-2-fluoro-2-deoxy-D-glucose (FDG) was studied with PET in 14 patients with non-Hodgkin's lymphomas. The low molecular weight fraction of venous plasma separated by fast gel filtration was used as the input function for 11C-methionine studies, and tracer accumulation was analyzed according to Patlak and Gjedde. The average uptake rate of 11C-methionine was 0.0775 {plus minus} 0.0245 min-1 (s.d.) and of FDG 0.0355 {plus minus} 0.0293 min-1, 11C-methionine uptake rate being significantly higher than that of FDG (p less than 0.01). Carbon-11-methionine accumulated strongly in all but one of the lymphomas. FDG accumulated clearly in lymphomas of high-grade malignancy, whereas two intermediate- and three low-grade malignant lymphomas had a poor uptake rate. The tumor/plasma ratio of both 11C-methionine and FDG increased faster in high and intermediate-grade lymphomas than in low-grade lymphomas, but there was considerable overlap between the histologic grades. Carbon-11-methionine seems to be preferable in detecting tumors, while FDG was superior to 11C-methionine in distinguishing the high-grade malignant lymphomas from the other grades.

  15. Estimation of Terrestrial COS Uptake From a Global Carbon Cycle Model (CLM-4.0)

    NASA Astrophysics Data System (ADS)

    Fu, W.; Dickinson, R. E.; Gu, L.; Hoffman, F. M.

    2012-12-01

    Carbonyl sulfide (COS), an analog of carbon dioxide is a useful atmospheric tracer of carbon cycle processes. Previous studies have shown that the rate of COS uptake is closely related to the rate of gross primary production (GPP). Here, we implemented mechanistic and empirical descriptions of leaf and soil COS uptake into a global land model featuring carbon and nitrogen interactions, the Community Land Model version 4 model, and obtained new COS flux estimates based on physiological and environmental conditions in the model. Also, using a simulation experiment, we demonstrated that some ecosystem variables, such as LRU (Leaf Relative Uptake) and ERU (Ecosystem Relative Uptake), could provide additional constraints on responses of photosynthesis and respiration to environmental forcings. The ERU calculated from CLM4.0 shows regional and seasonal differences in the balance of ecosystem respiration (RECO) and GPP, and atmospheric measurements of ERU should reflect this variation. Understanding these ecosystem variables is essential for improving predictions of future responses of the terrestrial biosphere to changing environmental conditions.

  16. Assessment of glutamine synthetase activity by [13N]ammonia uptake in living rat brain.

    PubMed

    Momosaki, Sotaro; Ito, Miwa; Tonomura, Misato; Abe, Kohji

    2015-01-01

    Glutamine synthetase (GS) plays an important role in glutamate neurotransmission or neurological disorder in the brain. [(13) N]Ammonia blood flow tracer has been reported to be metabolically trapped in the brain via the glutamate-glutamine pathway. The present study investigated the effect of an inhibitor of GS on [(13) N]ammonia uptake in order to clarify the feasibility of measuring GS activity in the living brain. l-Methionine sulfoximine (MSO), a selective GS inhibitor was microinjected into the ipsilateral striatum in rats. [(13) N]Ammonia uptake was quantified by autoradiography method as well as small animal positron emission tomography (PET) scans. The GS activity of the brain homogenate was assayed from the γ-glutamyl transferase reaction. Autoradiograms showed a decrease of [(13) N]ammonia radioactivity on the MSO-injected side compared with the saline-injected side of the striatum. This reduction could be detected with a small animal PET scanner. MSO had no effect on cerebral blood flow measured by uptake of [(15) O]H2 O. The reduction of [(13) N]ammonia uptake was closely related to the results of GS activity assay. These results indicated that [(13) N]ammonia may enable measurement of GS activity in the living brain.

  17. Relating phosphorus uptake to changes in transient storage and streambed sediment characteristics in headwater tributaries of Valley Creek, an urbanizing watershed

    NASA Astrophysics Data System (ADS)

    Ryan, Robert J.; Packman, Aaron I.; Kilham, Susan S.

    2007-04-01

    SummaryPhosphorus uptake dynamics were examined in two small streams in the Valley Creek watershed, located in an urbanizing area approximately 30 km west of Philadelphia, Pennsylvania, USA. The goal of this research was to examine how phosphorus uptake is influenced by temporal changes in bed sediment characteristics and transient storage in streams within an urbanizing watershed. We conducted tracer studies with a conservative solute, observed phosphorus uptake in situ and in laboratory experiments, and measured fine bed sediment grain size distributions and chemical compositions at both sites. At the Morehall Rd. site, the total laboratory and in situ uptake rates were related to the silt-clay ( d < 50 μm) content of the fine ( d < 2 mm) bed sediment and the sediment phosphorus concentration. The in situ uptake rate was also related to the sediment magnesium content and the transient storage exchange rate and area. At the Sheldrake Rd. site, the phosphorus uptake rates observed in situ and in the laboratory were not significantly related to any of the measured stream or sediment characteristics. However, the areal average uptake (uptake flux), was related to the transient storage exchange rate. In addition, the abiotic contribution to in situ uptake was evaluated by comparing the in situ and laboratory measured uptake rates. The total abiotic in situ uptake rate was found to be related to the bed sediment silt-clay content and the transient storage residence time, while the abiotic uptake flux was related to the transient storage residence time. Overall, these urbanizing streams were less efficient at removing phosphorus from the water column than forested streams in non-urban settings.

  18. Chemical tracer test at the Dixie Valley geothermal field, Nevada. Geothermal Reservoir Technology research program

    SciTech Connect

    Adams, M.C.; Moore, J.N.; Benoit, W.R.; Doughty, C.; Bodvarsson, G.S.

    1993-10-01

    In the injection test described, chemical tracers established the fluid flow between one injection well and one production well. Measured tracer concentrations, calculated flow rates, sampling schedules, and the daily events of the tracer test are documented. This experiment was designed to test the application of organic tracers, to further refine the predictive capability of the reservoir model, and to improve the effectiveness of Oxbow`s injection strategy.

  19. Early Detection of Cerebral Glucose Uptake Changes in the 5XFAD Mouse

    PubMed Central

    I.R, Macdonald; D.R, DeBay; G.A, Reid; T.P, O’Leary; C.T, Jollymore; G, Mawko; S, Burrell; E, Martin; C.V, Bowen; R.E, Brown; S, Darvesh

    2014-01-01

    Brain glucose hypometabolism has been observed in Alzheimer’s disease (AD) patients, and is detected with 18F radiolabelled glucose, using positron emission tomography. A pathological hallmark of AD is deposition of brain β-amyloid plaques that may influence cerebral glucose metabolism. The five times familial AD (5XFAD) mouse is a model of brain amyloidosis exhibiting AD-like phenotypes. This study examines brain β-amyloid plaque deposition and 18FDG uptake, to search for an early biomarker distinguishing 5XFAD from wild-type mice. Thus, brain 18FDG uptake and plaque deposition was studied in these mice at age 2, 5 and 13 months. The 5XFAD mice demonstrated significantly reduced brain 18FDG uptake at 13 months relative to wild-type controls but not in younger mice, despite substantial β-amyloid plaque deposition. However, by comparing the ratio of uptake values for glucose in different regions in the same brain, 5XFAD mice could be distinguished from controls at age 2 months. This method of measuring altered glucose metabolism may represent an early biomarker for the progression of amyloid deposition in the brain. We conclude that brain 18FDG uptake can be a sensitive biomarker for early detection of abnormal metabolism in the 5XFAD mouse when alternative relative uptake values are utilized. PMID:24801216

  20. Synthesis and evaluation of [(18)F]-fluoromethyl triphenylphosphonium cation as a novel mitochondria-specific positron emission tomography tracer.

    PubMed

    Zeng, Huahui; Wu, Xiangxiang; Song, Fahuan; Xu, Caiyun; Liu, Hao; Liu, Wendi

    2016-08-08

    We developed a radiosynthesis of the voltage sensitive tracer [(18)F]-fluoromethyltriphenylphosphonium cation ([(18)F]-FTPMP), giving high yield (30-34%, decay-corrected), radiochemical purity (>99%) and specific activity (about 760 GBq/μmol). [(18)F]-FTPMP had suitable lipophilicity (logP = 0.91 ± 0.03) and high in vivo/vitro stability. Biodistribution studies showed that [(18)F]-FTPMP had high heart uptake (>7%ID/g from 10 min to 120 min postinjection) and rapid clearance from the background. Clear cardiac images were obtained at different time periods, and the infarction areas could be detected sensitively with small-animal PET. The autoradiography and myocardial membrane potential studies confirmed the mitochondria specific of [(18)F]-FTPMP in rat myocardia. These excellent pharmacokinetic properties suggest [(18)F]-FTPMP is a promising mitochondria-specific tracer for clinical PET imaging of myocardial diseases associated with mitochondrial dysfunction.

  1. Dissipation of hydrological tracers and the herbicide S-metolachlor in batch and continuous-flow wetlands.

    PubMed

    Maillard, Elodie; Lange, Jens; Schreiber, Steffi; Dollinger, Jeanne; Herbstritt, Barbara; Millet, Maurice; Imfeld, Gwenaël

    2016-02-01

    Pesticide dissipation in wetland systems with regard to hydrological conditions and operational modes is poorly known. Here, we investigated in artificial wetlands the impact of batch versus continuous-flow modes on the dissipation of the chiral herbicide S-metolachlor (S-MET) and hydrological tracers (bromide, uranine and sulforhodamine B). The wetlands received water contaminated with the commercial formulation Mercantor Gold(®) (960 g L(-1) of S-MET, 87% of the S-enantiomer). The tracer mass budget revealed that plant uptake, sorption, photo- and presumably biodegradation were prominent under batch mode (i.e. characterized by alternating oxic-anoxic conditions), in agreement with large dissipation of S-MET (90%) under batch mode. Degradation was the main dissipation pathway of S-MET in the wetlands. The degradate metolachlor oxanilic acid (MOXA) mainly formed under batch mode, whereas metolachlor ethanesulfonic acid (MESA) prevailed under continuous-flow mode, suggesting distinct degradation pathways in each wetland. R-enantiomer was preferentially degraded under batch mode, which indicated enantioselective biodegradation. The release of MESA and MOXA by the wetlands as well as the potential persistence of S-MET compared to R-MET under both oxic and anoxic conditions may be relevant for groundwater and ecotoxicological risk assessment. This study shows the effect of batch versus continuous modes on pollutant dissipation in wetlands, and that alternate biogeochemical conditions under batch mode enhance S-MET biodegradation.

  2. Contrasting food web linkages for the grazing pathway in 3 temperate forested streams using {sup 15}N as a tracer

    SciTech Connect

    Tank, J.L.; Mulholland, P.J.; Meyer, J.L.; Bowden, W.B.; Webster, J.R.; Peterson, B.J.

    1998-11-01

    Nitrogen is a critical element controlling the productivity and dynamics of stream ecosystems and many streams are limited by the supply of biologically available nitrogen. The authors are learning more about the fate of inorganic nitrogen entering streams through {sup 15}N tracer additions. The Lotic Intersite Nitrogen Experiment (LINX) is studying the uptake, cycling, and fate of {sup 15}N-NH{sub 4} in the stream food web of 10 streams draining different biomes. Using the {sup 15}N tracer method and data from 3 sites in the study, the authors can differentiate patterns in the cycling of nitrogen through the grazing pathway (N from the epilithon to grazing macroinvertebrates) for 3 temperate forested streams. Here, they quantify the relationship between the dominant grazer and its proposed food resource, the epilithon, by comparing {sup 15}N levels of grazers with those of the epilithon, as well as the biomass, nitrogen content, and chlorophyll a standing stocks of the epilithon in 3 streams.

  3. In vitro positron emission tomography (PET): use of positron emission tracers in functional imaging in living brain slices.

    PubMed

    Matsumura, K; Bergström, M; Onoe, H; Takechi, H; Westerberg, G; Antoni, G; Bjurling, P; Jacobson, G B; Långström, B; Watanabe, Y

    1995-05-01

    Positron-emitting radionuclides have short half-lives and high radiation energies compared with radioisotopes generally used in biomedical research. We examined the possibility of applying positron emitter-labeled compounds to functional imaging in brain slices kept viable in an oxygenated buffer solution. Brain slices (300 microns thick) containing the striatum were incubated with positron emitter-labeled tracers for 30-45 min. The slices were then rinsed and placed on the bottom of a Plexiglas chamber filled with oxygenated Krebs-Ringer solution. The bottom of the chamber consisted of a thin polypropylene film to allow good penetration of beta+ particles from the brain slices. The chamber was placed on a storage phosphor screen, which has a higher sensitivity and a wider dynamic range than X-ray films. After an exposure period of 15-60 min, the screen was scanned by the analyzer and radioactivity images of brain slices were obtained within 20 min. We succeeded in obtaining quantitative images of (1) [18F]fluorodeoxyglucose uptake, (2) dopamine D2 receptor binding, (3) dopa-decarboxylase activity, and (4) release of [11C]dopamine preloaded as L-[11C]DOPA in the brain slice preparation. These results demonstrate that positron emitter-labeled tracers in combination with storage phosphor screens are useful for functional imaging of living brain slices as a novel neuroscience technique.

  4. Development of Fluorine-18 Labeled Metabolically Activated Tracers for Imaging of Drug Efflux Transporters with Positron Emission Tomography.

    PubMed

    Sander, Kerstin; Galante, Eva; Gendron, Thibault; Yiannaki, Elena; Patel, Niral; Kalber, Tammy L; Badar, Adam; Robson, Mathew; Johnson, Sean P; Bauer, Florian; Mairinger, Severin; Stanek, Johann; Wanek, Thomas; Kuntner, Claudia; Kottke, Tim; Weizel, Lilia; Dickens, David; Erlandsson, Kjell; Hutton, Brian F; Lythgoe, Mark F; Stark, Holger; Langer, Oliver; Koepp, Matthias; Årstad, Erik

    2015-08-13

    Increased activity of efflux transporters, e.g., P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP), at the blood-brain barrier is a pathological hallmark of many neurological diseases, and the resulting multiple drug resistance represents a major clinical challenge. Noninvasive imaging of transporter activity can help to clarify the underlying mechanisms of drug resistance and facilitate diagnosis, patient stratification, and treatment monitoring. We have developed a metabolically activated radiotracer for functional imaging of P-gp/BCRP activity with positron emission tomography (PET). In preclinical studies, the tracer showed excellent initial brain uptake and clean conversion to the desired metabolite, although at a sluggish rate. Blocking with P-gp/BCRP modulators led to increased levels of brain radioactivity; however, dynamic PET did not show differential clearance rates between treatment and control groups. Our results provide proof-of-concept for development of prodrug tracers for imaging of P-gp/BCRP function in vivo but also highlight some challenges associated with this strategy.

  5. The Five-Year Fate of a 15N Tracer in a Mixed Deciduous Forest: Retention, Redistribution, and Differences by Mycorrhizal Association

    NASA Astrophysics Data System (ADS)

    Goodale, C. L.

    2015-12-01

    The impact of nitrogen deposition on forest ecosystems depends in large part on its fate: uptake by trees can stimulate growth, while gaseous or leaching losses contribute to air and water pollution and represent the loss of a limiting nutrient. Past tracer studies have shown that soils dominate the short-term fate of added 15N, but its longer-term term fate remains uncertain. This study examined how much 15N tracer moved plant or soil pools or was lost over 5-6 years. In 2007, a 15N tracer (0.21 kg/ha as 99% enriched 15N-KNO3) was added to 0.25 ha mixed hardwood forest in central NY. All of the tracer was recovered in the days after its addition, but recovery fell to 78% by the end of this year (25% surface litter, 48% 0-10 cm soil, 5% roots). One year later, recovery in these pools fell (to 51%), with losses from surface litter (-11%) and the 0-10 cm soils (-15%), including losses from the "heavy" soil fraction. Additional tracer moved to other plant pools (+5%) and to deeper soil (+13%; up to 30 cm), for a total recovery of 69% of the added tracer. Between years 1 and 5-6, only total tracer recovery decreased by only 1.4%. Recovery decreased in foliage (-0.2%), all roots (-3.5%), and surface litter (-9.8%), while increasing in woody biomass (+0.9%), 0-10 cm soil (+8.9%), and deep soil (+2.3%; up to 50 cm). Tracer recovery in live and dead plant N pools (11%) did not change, as 3% moved from roots into aboveground plant tissues and 3% moved from live plant pools into leaf litter; these results imply no net transfer of 15N from soil to plants during this period. Over all 5-6 years, only 1.6% of the tracer moved into bark or wood, a small but important sink because of its high C:N ratio; however, roughly one-third of this total was in wood formed prior to the start of the tracer addition. Tree species differed in their recovery of 15N: the six species with ectomycorrhizal associations showed more enrichment than the four species with arbuscular mycorrhizae. It is

  6. Direct measurements of in-stream nitrate uptake with automated high frequency sensors

    NASA Astrophysics Data System (ADS)

    Kunz, Julia Vanessa; Hensley, Robert; Brase, Lisa; Borchardt, Dietrich; Rode, Michael

    2016-04-01

    Decades of nutrient studies have unveiled the importance of river networks in nutrient cycling. Still, direct methods to quantify instream removal in defined reaches have so far been limited to small streams. In rivers, where isotope tracer additions have been impracticable, uptake rates could only very rarely be measured and therefore have been mostly modelled by upscaling. Recently, the expanding availability of high resolution stream solute signals from automated sensors offers new possibilities for uptake kinetic studies. Cohen et al (2012) assessed assimilation and denitrification rates based on daily nitrate amplitudes and longitudinal concentration gradients in spring- fed chemostatic rivers. In higher order streams, overlapping of network, onsite and upstream signals require additional conceptual and methodological adaptation. Here we present a new combined longitudinal lagrangian and mass balance approach with continuous measurements of nitrate uptake rates in the German lowland river Weiße Elster, to our knowledge the first direct measurement of nitrate kinetics with continues high frequency sensors. We used 10 minutes time step NO3-N, pH, specific conductivity, dissolved oxygen, temperature and chlorophyl-a measurements and supplementing low frequency 15N isotope manual sampling. Longitudinal lagrangian measurements were conducted during day and night. Our data from two morphologically highly contrasting reaches indicate that local, seasonal or even day to day changes in uptake kinetics can be of several orders of magnitude and that the disregard of intermediate storage and dispersion can lead to high errors. The natural river reach revealed considerably higher N uptake than the channelized river reach. Furthermore, river bottom related N-uptake rates were in the same order than those found in agricultural head water streams. Besides depicting prospects and limits, we also provide important considerations for the set-up of measurement stations and for

  7. Dual Tracer PET Imaging (68Ga-DOTATATE and 18F-FDG) Features in Pulmonary Carcinoid: Correlation with Tumor Proliferation Index

    PubMed Central

    Bhatkar, Dhiraj; Utpat, Ketaki; Basu, Sandip; Joshi, Jyotsna M.

    2017-01-01

    Pulmonary carcinoid tumors are rare group of lung neoplasms representing 1% of all the lung tumors. The typical bronchial carcinoids showed higher and more selective uptake of 68Ga-DOTATATE than of 18F-FDG on PET-CT. The Ki-67(MIB-1), a tumor proliferation index is a prognostic marker in neuroendocrine tumors for estimating tumor progression. Atypical carcinoids have higher Ki-67 index and have an increased propensity to metastasize as compared to typical ones. 68Ga-DOTATATE PET imaging along with Ki-67 can be correlated for better management of patients with neuroendocrine tumors. We describe the dual tracer imaging features in a patient of pulmonary carcinoid with avid 68Ga-DOTATATE and minimal 18FDG (18Flurodeoxyglucose) uptake diagnosed on the basis of imaging and bronchoscopic biopsy and its correlation with tumor proliferation index. PMID:28242984

  8. Calcified peritoneal metastasis identified on 18F-fluoride positron emission tomography/computed tomography: Importance of extraosseous uptake of F-18 fluoride.

    PubMed

    Verma, Priyanka; Chandra, Piyush; Agrawal, Archi; Purandare, Nilendu; Shah, Sneha; Rangarajan, Venkatesh

    2016-01-01

    F-18 NaF positron emission tomography/computed tomography (PET/CT) is used for the evaluation of malignant and nonmalignant osseous disease. Extraosseous uptake of 18 fluoride-NaF has been observed in the arterial vasculature, gastrointestinal tract, and genitourinary tract. We describe a case of a woman with carcinoma of unknown primary in whom F-18 NaF PET/CT showed tracer uptake in the calcified peritoneal metastasis. Extraosseous findings on F-18 NaF PET/CT, though rare, may be visualized and may result in important management changes.

  9. Initial plasma disappearance and tissue uptake of 131I-albumin in normal rabbits

    SciTech Connect

    Bent-Hansen, L. )

    1991-05-01

    The simultaneous plasma disappearance curves of 131I-albumin and 125I-fibrinogen were recorded in normal rabbits for 1 hr. Using fibrinogen as a plasma reference, the disappearance curves of albumin were shown to contain two separate phases of efflux: one fast from zero to 10 min. comprising 8% of the total tracer; and one slow appearing in the interval of 10 to 60 min. containing another 9% of the tracer. Total albumin escape was analyzed to yield an initial slope of 0.024 {plus minus} 0.004 min-1, corresponding to a wholebody unidirectional albumin clearance (Cl(0)) of 0.090 {plus minus} 0.009 ml(min{asterisk}100 g)-1. The distribution of efflux was assessed by biopsy uptakes using the same tracers in spleen, kidney, heart, lung, liver, intestine, skin, muscle, and brain. The disappearance curve generally reflects a biphasic pattern of uptake in peripheral tissue, predominantly by muscle and lung. The rapid phase has contributions from the fast near equilibration of liver, and intestine and skin are significant codeterminants of the slow phase. Due to their low body masses highly perfused organs such as kidney, spleen, and heart have little influence on the plasma disappearance. In accordance, the Cl(0) determined for the wholebody was higher than initial clearances found in skin (0.053 ml(min{asterisk}100 g)-1) and muscle (0.054 ml(min{asterisk}100 g)-1), but much lower than those found in the highly perfused organs. The initial (unidirectional) rates of peripheral albumin transfer demonstrated, ranged from 10 to 30 times higher than estimates of lymphatic return, suggesting that transcapillary albumin exchange is mediated by high-rate bidirectional diffusion. The rapid decrease of net albumin exchange rates suggests a second, highly significant barrier located within the interstitial matrix, which restricts plasma escape and reduces plasma to lymph albumin transport.

  10. Sleep Physiology, Abnormal States, and Therapeutic Interventions

    PubMed Central

    Wickboldt, Alvah T.; Bowen, Alex F.; Kaye, Aaron J.; Kaye, Adam M.; Rivera Bueno, Franklin; Kaye, Alan D.

    2012-01-01

    Sleep is essential. Unfortunately, a significant portion of the population experiences altered sleep states that often result in a multitude of health-related issues. The regulation of sleep and sleep-wake cycles is an area of intense research, and many options for treatment are available. The following review summarizes the current understanding of normal and abnormal sleep-related conditions and the available treatment options. All clinicians managing patients must recommend appropriate therapeutic interventions for abnormal sleep states. Clinicians' solid understanding of sleep physiology, abnormal sleep states, and treatments will greatly benefit patients regardless of their disease process. PMID:22778676

  11. Congenital abnormalities of the ovine paramesonephric ducts.

    PubMed

    Smith, K C; Long, S E; Parkinson, T J

    1995-01-01

    A 15 month survey of ovine reproductive tracts was undertaken in slaughterhouses in southwest England. A total of 33506 tracts were examined; 23536 from lambs and 9970 from adults. In total, 3.4% of tracts were pregnant and 3.3% exhibited abnormalities. Twenty cases of uterus unicornis, six of uterus didelphys and 11 of segmental aplasia were encountered, such that partial aplasia of the paramesonephric ducts accounted for 3.3% of all abnormalities. Although developmental abnormalities of the ovine female genital system are relatively uncommon, a substantial proportion of these can be accounted for by development defects of the paramesonephric ducts.

  12. [Radionuclide studies of congenital kidney abnormalities].

    PubMed

    Vlakhov, N

    1984-06-01

    Using the potentialities of isotope nephrograms as a screening test a total of 4746 patients suspected of renal abnormalities were examined. The author established pathological deviations in 561 cases (11.8%). During further verification using scintigraphy unsuspected congenital renal abnormalities (aplasia, hypoplasia, dystopia, double kidney, horseshoe kidney, solitary cyst and polycystic renal disease) were found in 46 patients (8.2%). The diagnosis was confirmed at subsequent venous x-ray urography. A conclusion has been made as to the role of comprehensive nephrographic-scintigraphic examination in the diagnosis of congenital renal abnormalities.

  13. Numerically abnormal chromosome constitutions in humans

    SciTech Connect

    1993-12-31

    Chapter 24, discusses numerically abnormal chromosome constitutions in humans. This involves abnormalities of human chromosome number, including polyploidy (when the number of sets of chromosomes increases) and aneuploidy (when the number of individual normal chromosomes changes). Chapter sections discuss the following chromosomal abnormalities: human triploids, imprinting and uniparental disomy, human tetraploids, hydatidiform moles, anomalies caused by chromosomal imbalance, 13 trisomy (D{sub 1} trisomy, Patau syndrome), 21 trisomy (Down syndrome), 18 trisomy syndrome (Edwards syndrome), other autosomal aneuploidy syndromes, and spontaneous abortions. The chapter concludes with remarks on the nonrandom participation of chromosomes in trisomy. 69 refs., 3 figs., 4 tabs.

  14. DNA Uptake by Transformable Bacteria

    SciTech Connect

    Lacks, Sanford A.

    1999-03-31

    The various processes of DNA uptake by cells can be categorized as: viral DNA entry, conjugation, or transformation. Within each category, a variety of mechanisms have been found. However, considerable similarities occur among the different mechanisms of conjugation and, especially, transformation. All of these natural mechanisms of DNA transfer are quite elaborate and involve multiple protein components, as the case may be, of the virus, the donor cell, and the recipient cell. The mechanisms of viral infection and conjugation will be discussed mainly with respect to their relevance to transformation.

  15. DNA UPTAKE BY TRANSFORMABLE BACTERIA

    SciTech Connect

    LACKS,S.A.

    1999-09-07

    The various processes of DNA uptake by cells can be categorized as: viral DNA entry, conjugation, or transformation. Within each category, a variety of mechanisms have been found. However, considerable similarities occur among the different mechanisms of conjugation and, especially, transformation. All of these natural mechanisms of DNA transfer are quite elaborate and involve multiple protein components, as the case may be, of the virus, the donor cell, and the recipient cell. The mechanisms of viral infection and conjugation will be discussed mainly with respect to their relevance to transformation.

  16. Assessment of Halon-1301 as a groundwater age tracer

    NASA Astrophysics Data System (ADS)

    Beyer, M.; van der Raaij, R.; Morgenstern, U.; Jackson, B.

    2015-01-01

    Groundwater dating is an important tool to assess groundwater resources in regards to their dynamics, i.e. direction and time scale of groundwater flow and recharge, to assess contamination risks and manage remediation. To infer groundwater age information, a combination of different environmental tracers, such as tritium and SF6, are commonly used. However, ambiguous age interpretations are often faced, due to a limited set of available tracers and their individual restricted application ranges. For more robust groundwater dating multiple tracers need to be applied complementarily and it is vital that additional, groundwater age tracers are found to ensure robust groundwater dating in future. We recently suggested that Halon-1301, a water soluble and entirely anthropogenic gaseous substance, may be a promising candidate, but its behaviour in water and suitability as a groundwater age tracer had not yet been assessed in detail. In this study, we determine Halon-1301 and infer age information in 17 New Zealand groundwaters and various modern (river) water samples. The samples are simultaneously analysed for Halon-1301 and SF6, which allows identification of issues such as contamination of the water with modern air during sampling. Water at all analysed groundwater sites have also been previously dated with tritium, CFC-12, CFC-11 and SF6, and exhibit mean residence times ranging from modern (close to 0 years) to over 100 years. The investigated groundwater ranged from oxic to highly anoxic, and some showed evidence of CFC contamination or degradation. This allowed us to make a first attempt of assessing the conservativeness of Halon-1301 in water, in terms of presence of local sources and its sensitivity towards degradation etc., which could affect the suitability of Halon-1301 as groundwater age tracer. Overall we found Halon-1301 reliably inferred the mean residence time of groundwater recharged between 1980 and 2014. Where direct age comparison could be made 71

  17. A Comparative Study of the Hypoxia PET Tracers [{sup 18}F]HX4, [{sup 18}F]FAZA, and [{sup 18}F]FMISO in a Preclinical Tumor Model

    SciTech Connect

    Peeters, Sarah G.J.A.; Zegers, Catharina M.L.; Lieuwes, Natasja G.; Elmpt, Wouter van; Eriksson, Jonas; Dongen, Guus A.M.S. van; Dubois, Ludwig; Lambin, Philippe

    2015-02-01

    Purpose: Several individual clinical and preclinical studies have shown the possibility of evaluating tumor hypoxia by using noninvasive positron emission tomography (PET). The current study compared 3 hypoxia PET tracers frequently used in the clinic, [{sup 18}F]FMISO, [{sup 18}F]FAZA, and [{sup 18}F]HX4, in a preclinical tumor model. Tracer uptake was evaluated for the optimal time point for imaging, tumor-to-blood ratios (TBR), spatial reproducibility, and sensitivity to oxygen modification. Methods and Materials: PET/computed tomography (CT) images of rhabdomyosarcoma R1-bearing WAG/Rij rats were acquired at multiple time points post injection (p.i.) with one of the hypoxia tracers. TBR values were calculated, and reproducibility was investigated by voxel-to-voxel analysis, represented as correlation coefficients (R) or Dice similarity coefficient of the high-uptake volume. Tumor oxygen modifications were induced by exposure to either carbogen/nicotinamide treatment or 7% oxygen breathing. Results: TBR was stabilized and maximal at 2 hours p.i. for [{sup 18}F]FAZA (4.0 ± 0.5) and at 3 hours p.i. for [{sup 18}F]HX4 (7.2 ± 0.7), whereas [{sup 18}F]FMISO showed a constant increasing TBR (9.0 ± 0.8 at 6 hours p.i.). High spatial reproducibility was observed by voxel-to-voxel comparisons and Dice similarity coefficient calculations on the 30% highest uptake volume for both [{sup 18}F]FMISO (R = 0.86; Dice coefficient = 0.76) and [{sup 18}F]HX4 (R = 0.76; Dice coefficient = 0.70), whereas [{sup 18}F]FAZA was less reproducible (R = 0.52; Dice coefficient = 0.49). Modifying the hypoxic fraction resulted in enhanced mean standardized uptake values for both [{sup 18}F]HX4 and [{sup 18}F]FAZA upon 7% oxygen breathing. Only [{sup 18}F]FMISO uptake was found to be reversible upon exposure to nicotinamide and carbogen. Conclusions: This study indicates that each tracer has its own strengths and, depending on the question to be answered, a different tracer can be put

  18. Identification and characterization of conservative organic tracers for use as hydrologic tracers for the Yucca Mountain Site Characterization Study; Progress report, June 1--December 31, 1990

    SciTech Connect

    Stetzenbach, K.J.

    1990-12-31

    Ground water tracers are solutes dissolved in or carried by ground water to delineate flow pathways. Tracers provide information on direction and speed of water movement and that of contaminants that might be conveyed by the water. Tracers can also be used to measure effective porosity, hydraulic conductivity, dispersivity and solute distribution coefficients. For most applications tracers should be conservative, that is, move at the same rate as the water and not sorb to aquifer materials. Tracers must have a number of properties to be functional. Regardless of the desired properties, the chemical and physical behavior of a tracer in ground water and the porous medium under study must be understood. Good estimates of tracer behavior can be obtained from laboratory studies. Studies in this proposal will address tracer properties with analytical method development, static sorption and degradation studies and column transport studies, Mutagenicity tests will be performed on promising candidates. The tracers that will be used for these experiments are fluorinated organic acids and other organic compounds that have the chemical and biological stability necessary to be effective in the Yucca Mountain environment. Special emphasis will be placed on compounds that fluoresce or have very large ultraviolet absorption coefficients for very high analytical sensitivity.

  19. Report to Congress on abnormal occurrences

    SciTech Connect

    Not Available

    1991-03-01

    Section 208 of the Energy Reorganization Act of 1974 identified an abnormal occurrence as an unscheduled incident or event that the Nuclear Regulatory Commission determines to be significant from the standpoint of public health or safety and requires a quarterly report of such events to be made to Congress. This report covers the period from October 1 through December 31, 1990. The report discusses five abnormal occurrences, none of which involved a nuclear power plant. Two involved significant overexposures to the hands of two radiographers, two involved medical therapy misadministrations, and one involved a medical diagnostic misadministration. No abnormal occurrences were reported by the Agreement States. The report also contains information that updates a previously reported abnormal occurrence. 8 refs.

  20. MRI Helps Assess Fetal Brain Abnormalities

    MedlinePlus

    ... decisions about their pregnancy," said lead author Paul Griffiths. He's a professor of radiology at the University ... the fetus may have a suspected brain abnormality," Griffiths said in a journal news release. In this ...

  1. Abnormal Position and Presentation of the Fetus

    MedlinePlus

    ... Interest (Quiz) Breast Cancer (Video) Overview of the Female Reproductive System (News) Study: Plenty of IV Fluids May Make Childbirth Safer, Easier (News) Zejula Approved for Certain Female Cancers Additional Content Medical News Abnormal Position and ...

  2. Abnormalities of lung function in hay fever.

    PubMed Central

    Morgan, E J; Hall, D R

    1976-01-01

    Twenty subjects with symptoms of hay fever were studied to see whether abnormalities could be detected in the function of small airways. The investigations included dynamic compliance at varying respiratory frequencies, closing capacity, residual volume, transfer factor, and maximal expiratory flow-volume curves. The tests were repeated in the winter when symptoms had resolved. Frequency dependence of compliance was found in eight subjects with symptoms (40%), closing capacities being abnormal in only two instances. Conventional pulmonary function tests, including expiratory flow rates at mid vital capacity, were within the predicted range of all subjects. When tests were repeated in the winter, frequency dependence of compliance was no longer present in subjects whose symptoms had resolved. The study suggests that reversible small airway abnormalities are present in a significant proportion of subjects with symptoms of hay fever and that such abnormalities are best detected by the measurement of dynamic compliance at varying respiratory frequencies. PMID:769243

  3. Ocean uptake of carbon dioxide

    SciTech Connect

    Peng, Tsung-Hung; Takahashi, Taro

    1993-06-01

    Factors controlling the capacity of the ocean for taking up anthropogenic C0{sup 2} include carbon chemistry, distribution of alkalinity, pCO{sup 2} and total concentration of dissolved C0{sup 2}, sea-air pCO{sup 2} difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and models of ocean-atmosphere system based on our understanding of these regulating processes axe used to estimate the magnitude of C0{sup 2} uptake by the ocean. We conclude that the ocean can absorb up to 35% of the fossil fuel emission. Direct measurements show that 55% Of C0{sup 2} from fossil fuel burning remains in the atmosphere. The remaining 10% is not accounted for by atmospheric increases and ocean uptake. In addition, it is estimated that an amount equivalent to 30% of recent annual fossil fuel emissions is released into the atmosphere as a result of deforestation and farming. To balance global carbon budget, a sizable carbon sink besides the ocean is needed. Storage of carbon in terrestrial biosphere as a result of C0{sup 2} fertilization is a potential candidate for such missing carbon sinks.

  4. Ocean uptake of carbon dioxide

    SciTech Connect

    Peng, Tsung-Hung ); Takahashi, Taro . Lamont-Doherty Earth Observatory)

    1993-01-01

    Factors controlling the capacity of the ocean for taking up anthropogenic C0[sup 2] include carbon chemistry, distribution of alkalinity, pCO[sup 2] and total concentration of dissolved C0[sup 2], sea-air pCO[sup 2] difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and models of ocean-atmosphere system based on our understanding of these regulating processes axe used to estimate the magnitude of C0[sup 2] uptake by the ocean. We conclude that the ocean can absorb up to 35% of the fossil fuel emission. Direct measurements show that 55% Of C0[sup 2] from fossil fuel burning remains in the atmosphere. The remaining 10% is not accounted for by atmospheric increases and ocean uptake. In addition, it is estimated that an amount equivalent to 30% of recent annual fossil fuel emissions is released into the atmosphere as a result of deforestation and farming. To balance global carbon budget, a sizable carbon sink besides the ocean is needed. Storage of carbon in terrestrial biosphere as a result of C0[sup 2] fertilization is a potential candidate for such missing carbon sinks.

  5. Medial medullary infarction: abnormal ocular motor findings.

    PubMed

    Kim, J Soo; Choi, K-D; Oh, S-Y; Park, S-H; Han, M-K; Yoon, B-W; Roh, J-K

    2005-10-25

    In 20 consecutive patients with isolated medial medullary infarction, abnormal ocular motor findings included nystagmus (n = 8), ocular contrapulsion (n = 5), and contralesional ocular tilt reaction (n = 2). The nystagmus was ipsilesional (n = 4), gaze-evoked (n = 5), upbeating (n = 4), and hemiseesaw (n = 1). The ocular motor abnormalities may be explained by involvements of the nucleus prepositus hypoglossi, medial longitudinal fasciculus or efferent fibers from the vestibular nuclei, climbing fibers, and cells of the paramedian tracts.

  6. Congenital abnormalities associated with extrahepatic portal hypertension.

    PubMed Central

    Odièvre, M; Pigé, G; Alagille, D

    1977-01-01

    Congenital abnormalities were present in 12 out of 30 (40%) children with extrahepatic portal hypertension of unknown cause, but in only 2 out of 17 (12%) children with extnahepatic portal hypertension secondary to umbilical vein catheterization or omphalitis. The most frequent abnormalities in this series and in published reports were atrial septal defect, malformation of the biliary tract, and anomalous inferior vena cava. These findings are consistent with the view that some cases with extrahepatic portal hypertension are congenital in origin. PMID:869567

  7. Congenital abnormalities associated with extrahepatic portal hypertension.

    PubMed

    Odièvre, M; Pigé, G; Alagille, D

    1977-05-01

    Congenital abnormalities were present in 12 out of 30 (40%) children with extrahepatic portal hypertension of unknown cause, but in only 2 out of 17 (12%) children with extnahepatic portal hypertension secondary to umbilical vein catheterization or omphalitis. The most frequent abnormalities in this series and in published reports were atrial septal defect, malformation of the biliary tract, and anomalous inferior vena cava. These findings are consistent with the view that some cases with extrahepatic portal hypertension are congenital in origin.

  8. Basilar artery migraine and reversible imaging abnormalities.

    PubMed

    Maytal, J; Libman, R B; Lustrin, E S

    1998-01-01

    We report a case of a basilar artery migraine in a 17-year-old boy with transient CT and MR abnormalities after each of two migraine episodes. A repeat MR study 6 months after the last event showed complete resolution of the lesion. Transient abnormalities on brain images similar to those shown in our case have been reported in patients with migraine and other neurologic conditions and are most likely related to cerebral vasogenic edema.

  9. Tracers and buoyancy driven dispersion in permeable rock

    NASA Astrophysics Data System (ADS)

    Woods, A.

    2015-12-01

    In this presentation, a series of new experiments and supporting theoretical models will be presented to illustrate some of the controls on the dispersal of tracers spreading through both homogeneous and heterogeneous porous media as governed by a buoyancy driven flow. Such flows may arise when water is injected into reservoirs, to displace oil, or during the injection of CO2 into deep saline aquifers as part of a geosequestration scheme. Tracers, which can be used to help identify the flow pattern and flow speed, can exhibit unusual trajectories within a porous layer when controlled by buoyancy driven flow, and may be hostage to the mixing effects of buoyancy driven shear dispersion. The effects of capillarity on such dispersion will also be discussed. A series of idealised models of the flow will be presented to illustrate some of the key phenomena through a combination of analogue bead pack experiments and theoretical calculations of the associated flow processes.

  10. Tracer Methods for Characterizing Fracture Creation in Engineered Geothermal Systems

    SciTech Connect

    Rose, Peter; Harris, Joel

    2014-05-08

    The aim of this proposal is to develop, through novel high-temperature-tracing approaches, three technologies for characterizing fracture creation within Engineered Geothermal Systems (EGS). The objective of a first task is to identify, develop and demonstrate adsorbing tracers for characterizing interwell reservoir-rock surface areas and fracture spacing. The objective of a second task is to develop and demonstrate a methodology for measuring fracture surface areas adjacent to single wells. The objective of a third task is to design, fabricate and test an instrument that makes use of tracers for measuring fluid flow between newly created fractures and wellbores. In one method of deployment, it will be used to identify qualitatively which fractures were activated during a hydraulic stimulation experiment. In a second method of deployment, it will serve to measure quantitatively the rate of fluid flowing from one or more activated fracture during a production test following a hydraulic stimulation.

  11. Conservative tracers for the C-well hydraulic testing

    SciTech Connect

    Dombrowski, T.; Coates, G.; Stetzenbach, K.J.

    1992-11-01

    This paper reports that work is being done to identify and characterize conservative organic tracers for use as groundwater tracers at the C-well complex. An evaluation of the chemical and biological stability of several compounds including fluorinated aliphatic and aromatic acids, fluorinated salicylic acids, and fluorinated cinnamic acids was carried out using tuff samples from the Yucca Mountain area and J13 or de-ionized water. Samples were monitored over a 60-day period for any decrease in concentration; the resulting data was evaluated for possible sorption or biological degradation of the candidate compound. The fluorinated benzoic acids show the greatest stability over the 60-day period. All analyses were carried out using an HPLC system, with either a fluorescence detector, a variable wavelength UV-VIS detector, or a quadrupole mass spectrometer.

  12. 13C Tracer Studies of Metabolism in Mouse Tumor Xenografts

    PubMed Central

    Lane, Andrew N.; Yan, Jun; Fan, Teresa W-M.

    2015-01-01

    Mice are widely used for human tumor xenograft studies of cancer development and drug efficacy and toxicity. Stable isotope tracing coupled with metabolomic analysis is an emerging approach for assaying metabolic network activity. In mouse models there are several routes of tracer introduction, which have particular advantages and disadvantages that depend on the model and the questions addressed. This protocol describes the bolus i.v. route via repeated tail vein injections of solutions of stable isotope enriched tracers including 13C6-glucose and 13C5,15N2-glutamine. Repeated injections give higher enrichments and over longer labeling periods than a single bolus. Multiple injections of glutamine are necessary to achieve adequate enrichment in engrafted tumors. PMID:26693168

  13. The extended use of tracers in teaching coal preparation

    SciTech Connect

    Cole, S.N.; Smith, P.; Horsfall, D.W.

    1995-08-01

    This paper discusses further the use of density tracers and coloured particles in the teaching of coal preparation and associated subjects. It is a follow up to the paper presented at Coal Prep `94 {open_quotes}Miniature Beneficiation{close_quotes}. As described in that paper, current uses include demonstrating gravity separation processes, and exercises to illustrate the principles of sampling and beneficiation plant efficiency testing. Future uses for tracers include a novel method to demonstrate the principles of practical dense medium separation and float and sink analysis; as well as programme to increase the students` awareness of sampling standards. The last-named applications has indicated possible deficiencies in the present system of sampling hard coal when seeking to determine certain analytical parameters.

  14. Vascular tracers alter hemodynamics and airway pressure in anesthetized sheep

    SciTech Connect

    Albertine, K.H.; Staub, N.C.

    1986-11-01

    The technique of vascular labeling was developed to mark sites of increased microvascular permeability. We used the vascular labeling technique in anesthetized sheep and found that hemodynamics and airway pressure were adversely affected by intraarterial infusions of two vascular tracers. Monastral blue (nine sheep) immediately caused systemic arterial hypotension, pulmonary arterial hypertension, and bronchoconstriction. All three physiological responses were partially blocked by a cyclooxygenase inhibitor (indomethacin) but not by an H1-antihistamine (chlorpheniramine). Colloidal gold (nine sheep) caused immediate, but less dramatic, pulmonary arterial hypertension which was not attenuated by the blocking agents. We conclude that these two vascular tracers caused detrimental physiological side effects in sheep at the usual doses used to label injured microvessels in other species.

  15. Artificial sweeteners as potential tracers of municipal landfill leachate.

    PubMed

    Roy, James W; Van Stempvoort, Dale R; Bickerton, Greg

    2014-01-01

    Artificial sweeteners are gaining acceptance as tracers of human wastewater in the environment. The 3 artificial sweeteners analyzed in this study were detected in leachate or leachate-impacted groundwater at levels comparable to those of untreated wastewater at 14 of 15 municipal landfill sites tested, including several closed for >50 years. Saccharin was the dominant sweetener in old (pre-1990) landfills, while newer landfills were dominated by saccharin and acesulfame (introduced 2 decades ago; dominant in wastewater). Cyclamate was also detected, but less frequently. A case study at one site illustrates the use of artificial sweeteners to identify a landfill-impacted groundwater plume discharging to a stream. The study results suggest that artificial sweeteners can be useful tracers for current and legacy landfill contamination, with relative abundances of the sweeteners potentially providing diagnostic ability to distinguish different landfills or landfill cells, including crude age-dating, and to distinguish landfill and wastewater sources.

  16. Characterization of [(123)I]IDAM as a novel single-photon emission tomography tracer for serotonin transporters.

    PubMed

    Kung, M P; Hou, C; Oya, S; Mu, M; Acton, P D; Kung, H F

    1999-08-01

    Development of selective serotonin transporter (SERT) tracers for single-photon emission tomography (SPET) is important for studying the underlying pharmacology and interaction of specific serotonin reuptake site inhibitors, commonly used antidepressants, at the SERT sites in the human brain. In search of a new tracer for imaging SERT, IDAM (5-iodo-2-[[2-2-[(dimethylamino)methyl]phenyl]thio]benzyl alcohol) was developed. In vitro characterization of IDAM was carried out with binding studies in cell lines and rat tissue homogenates. In vivo binding of [(125)I]IDAM was evaluated in rats by comparing the uptakes in different brain regions through tissue dissections and ex vivo autoradiography. In vitro binding study showed that IDAM displayed an excellent affinity to SERT sites (K(i)=0.097 nM, using membrane preparations of LLC-PK(1) cells expressing the specific transporter) and showed more than 1000-fold of selectivity for SERT over norepinehrine and dopamine (expressed in the same LLC-PK(1) cells). Scatchard analysis of [(125)I]IDAM binding to frontal cortical membrane homogenates prepared from control or p-chloroamphetamine (PCA)-treated rats was evaluated. As expected, the control membranes showed a K(d) value of 0.25 nM+/-0.05 nM and a B(max) value of 272+/-30 fmol/ mg protein, while the PCA-lesioned membranes displayed a similar K(d), but with a reduced B(max) (20+/-7 fmol/ mg protein). Biodistribution of [(125)I]IDAM (partition coefficient =473; 1-octanol/buffer) in the rat brain showed a high initial uptake (2.44%dose at 2 min after i.v. injection) with the specific binding peaked at 60 min postinjection (hypothalamus-cerebellum/cerebellum =1.75). Ex vivo autoradiographs of rat brain sections (60 min after i.v. injection of [(125)I]IDAM) showed intense labeling in several regions (olfactory tubercle, lateral septal nucleus, hypothalamic and thalamic nuclei, globus pallidus, central gray, superior colliculus, substantia nigra, interpeduncular nucleus, dorsal

  17. Linear distribution of nematodes in the gastrointestinal tract of tracer lambs.

    PubMed

    Makovcová, Katerina; Langrová, Iva; Vadlejch, Jaroslav; Jankovská, Ivana; Lytvynets, Andriy; Borkovcová, Marie

    2008-12-01

    Forty-eight tracer lambs were killed in 2004-2007. The abomasum, duodenum, small intestine (jejunum and ileum), colon and caecum were collected and processed for parasites enumeration and identification-mucosal scrapings of both abomasums and intestines were digested. Out of 48 gastrointestinal tracts examined, all were found to be positive for nematode infection. Seventeen species of gastrointestinal nematodes were recovered: Bunostomum trigonocephalum, Cooperia curticei, Haemonchus contortus, Chabertia ovina, Nematodirus battus, Nematodirus filicollis, Oesophagostomum venulosum, Teladorsagia circumcincta, Trichostrongylus axei, Trichostrongylus colubriformis, Trichostrongylus vitrinus, Strongyloides papillosus, Trichuris ovis, Trichuris globulosa, Trichuris skrjabini and Skrjabinema ovis. All species were searched for in the entire gastrointestinal tract. Six species of nematodes were recovered from abnormal sites, naturally in small numbers of lambs as well as in small amounts: Nematodirus battus in the abomasums (6.67% of lambs), N. filicollis in the caecum and in the colon (%4 and 8%, respectively), T. axei in the colon (9.52%), T. colubriformis in the colon (13.89%), T. vitrinus in the caecum (16.67%), in the colon (20.00%) and in the abomasum (3.33%). T. ovis was found in one case in the small intestine.

  18. A Comparison of Spiral Tracers in M81: Erratum

    NASA Astrophysics Data System (ADS)

    Kaufman, Michele; Bash, Frank N.; Hine, Butler; Rots, Arnold H.; Elmegreen, Debra M.; Hodge, Paul W.

    1990-05-01

    In the paper "A Comparison of Spiral Tracers in M81" by Michele Kaufman, Frank N. Bash, Butler Hine, Arnold H. Rots, Debra M. Elmegreen, and Paul W. Hodge (Ap. J., 345, 674 [1989]), Figure 1 (Plate 7) was miscentered, and as a result the labels on be vertical axis on the left-hand side of the H I image were cut off. The separation between tick marks on the vertical axis is 200", the same as on the horizontal axis.

  19. Hanford facilities tracer study report (315 Water Treatment Facility)

    SciTech Connect

    Ambalam, T.

    1995-04-14

    This report presents the results and findings of a tracer study to determine contact time for the disinfection process of 315 Water Treatment Facility that supplies sanitary water for the 300 Area. The study utilized fluoride as the tracer and contact times were determined for two flow rates. Interpolation of data and short circuiting effects are also discussed. The 315 Water Treatment Facility supplies sanitary water for the 300 Area to various process and domestic users. The Surface Water Treatment Rule (SWTR), outlined in the 1986 Safe Drinking Water Act Amendments enacted by the EPA in 1989 and regulated by the Washington State Department of Health (DOH) in Section 246-290-600 of the Washington Administrative Code (WAC), stipulates filtration and disinfection requirements for public water systems under the direct influence of surface water. The SWTR disinfection guidelines require that each treatment system achieves predetermined inactivation ratios. The inactivation by disinfection is approximated with a measure called CxT, where C is the disinfectant residual concentration and T is the effective contact time of the water with the disinfectant. The CxT calculations for the Hanford water treatment plants were derived from the total volume of the contact basin(s). In the absence of empirical data to support CxT calculations, the DOH determined that the CxT values used in the monthly reports for the water treatment plants on the Hanford site were invalid and required the performance of a tracer study at each plant. In response to that determination, a tracer study will be performed to determine the actual contact times of the facilities for the CxT calculations.

  20. Transient Tracers as a Problem in Control Theory

    DTIC Science & Technology

    1988-07-15

    New Yoik, 1979. discrete one. There may be difficult questions of what consti- Meditch , J. S., A survey of data smoothing for linear and nonlinear...tracer concentrations at earlier times using a smoothing filter. 1. INTRODUCTION problem was solved. By regularization is meant the problem Direct...onboundaries and in the interior.) The question leads to the Kalman "smoother" we follow Liebelt [1967, p. 198] and Meditch [1973] and use the Rauch

  1. Thermal tracer tomography: from numerical simulation to field implementation

    NASA Astrophysics Data System (ADS)

    Somogyvári, Márk; Brauchler, Ralf; Bayer, Peter

    2016-04-01

    Choosing heat for subsurface investigations is attractive because changes in temperature can be easily measured, and natural variations are typically slower than the timescale of the experiments. The tomographical setup expands the applicability of such tests to reconstruct the spatial distribution of hydraulic aquifer properties. A new inversion methodology is presented for thermal tracer tomography, using tracer travel times to invert the hydraulic conductivity distribution of the aquifer. If we can assume that heat transport is driven by advection, the travel time of the thermal tracer can be related to the hydraulic parameters of the aquifer. With this assumption other thermal effects such as thermal diffusion or density driven flow appear as noise in the results. To reduce these effects the early time diagnostics of the recorded breakthrough curves are used, focusing on the fastest transport routes between the sources and receivers. The inverse problem of the experiment thus can be formulated as a classical travel time problem, and it can be solved using standard eikonal solver algorithms known from seismic or hydraulic tomography. The method is demonstrated with a high resolution 3-D aquifer analog dataset. The generated 3-D reconstruction reveals the potential of the method, especially in finding the preferential flow paths within the aquifer. Aside from this, the developed method is computationally efficient and can provide results in a fragment of the time required for full-physics model calibration. The method is also tested under field conditions. Four heat tracer injections were performed during a three day field campaign at the Widen field site in northeast Switzerland. Pulse signals were used and the temperature evolution was measured downstream using a distributed measurement system. The preliminary results of the tomographic inversion correspond well with the findings of earlier studies from the field site imaging the same geological features as

  2. Development of luminescent bacteria as tracers for geological reservoir characterization

    SciTech Connect

    King, J.W.

    1990-09-01

    This research project resulted from recognizing the problem of being unable to accurately distinguish communication between wells in producing oil zones which may or may not be continuous. Bioluminescent bacteria are being developed for use as tracers in reservoir characterization. A pure culture of Photobacterium phosphoreum is being studied in the laboratory for accurate monitoring schemes. A search of the literature and communications with marine microbiologists indicate that bioluminescent bacteria can be easily studied in vitro.

  3. Tracers as Tools in Characterizing Watersheds as Integrated Hydroecological Systems

    NASA Astrophysics Data System (ADS)

    Soulsby, C.; Tetzlaff, D.; Malcolm, I. A.; Waldron, S.; Dunn, S. M.

    2006-12-01

    Increasingly characterization of watersheds is involving integrating hydrologic, geomorphic and ecological perspectives on how freshwater systems function as a scientific basis for sustainable management. Environmental tracers have great potential for integrated characterization of watersheds at a range of spatial and temporal scales: They can be used, for example, to examine residence time distributions and runoff source dynamics. In recent years, tracer data sets have become available for increasing numbers of catchments and more sites have longer-term (>10 years) records. These data resources are improving insights into how hydrological functional descriptors - such as mean residence time - can vary with spatial scale, and how they are affected by climatic variability at different temporal scales. Combining such tracer- based conceptualization of hydrology with GIS analysis of catchment characteristics has powerful potential in identifying the relative importance of varying landscape controls on hydrological response and facilitate process conceptualization of larger mesoscale (>100km2) catchments where management decisions are needed - rather than traditional small (1km2) experimental basins. Such GIS analysis also allows the hydrological function of larger catchments to be related to their geomorphic structure and landscape organization. In this contribution, analysis of tracer data sets from mesoscale experimental basins in Scotland, will be integrated with GIS-based analysis to characterize hydrological functioning and identify the dominant landscape controls at different spatial scales. This is then used to help understand the dynamics of the physico-chemical processes that provide the physical template of ecological habitats in river systems in mesoscale watershed. The biological responses to such dynamic hydrological characteristics will be illustrated with respect to Atlantic salmon rivers.

  4. Effects of mixing-induced irradiance fluctuations on nitrogen uptake in size-fractionated coastal phytoplankton communities

    NASA Astrophysics Data System (ADS)

    Maguer, Jean-François; L'Helguen, Stéphane; Waeles, Matthieu

    2015-03-01

    In coastal waters subjected to strong tidal forcing, phytoplankton populations are exposed to highly variable light regimes. To grow under such fluctuating light environments, phytoplankton adjust their physiological properties. Here, we investigated nitrogen (N) uptake patterns in the western English Channel to determine whether phytoplankton modify their physiological processes involved in N uptake in response to changing irradiance conditions induced by spring-neap tidal cycles. Nitrate (NO3-) and ammonium (NH4+) uptake kinetics as a function of irradiance (VN-E curves) were assessed using 15N tracer techniques on two size fractions (<10 and >10 μm) of phytoplankton collected at 50% and 1% of surface irradiance during two spring-neap tidal cycles. Overall, the results showed that both small and large phytoplankton, whatever their vertical position in the water column, increased their maximum uptake capacity and their light utilization efficiency for the two N substrates following the decrease in vertical mixing intensity. Moreover, the improvement of irradiance conditions at neap tides was of greater benefit for the larger cells than for the smaller ones and was more favorable for NO3- uptake than for NH4+ uptake. These findings show that the light regime fluctuation resulting from the relaxation of tidal mixing during spring-neap tidal cycle leads to profound physiological adjustments of N uptake processes in phytoplankton communities. They suggest that the changes in NO3- uptake by large phytoplankton associated with the fortnightly spring-neap tidal cycle can account for most of the deviation in background productivity in the western English Channel which is based on NH4+ and is dominated by small cells. The dynamic light regime inherent to macrotidal coastal ecosystems could therefore determine, to a large extent, the importance of new vs. regenerated production as well as the size structure of the phytoplankton community.

  5. Nitrogen fluxes at the root-soil interface show a mismatch of nitrogen fertilizer supply and sugarcane root uptake capacity

    NASA Astrophysics Data System (ADS)

    Inselsbacher, Erich; Schmidt, Susanne; Näsholm, Torgny; Robinson, Nicole; Guillou, Stéphane; Vinall, Kerry; Lakshmanan, Prakash; Brackin, Richard

    2016-04-01

    Nitrogen (N) uptake by agricultural crops is a key constituent of the global N cycle, as N captured by roots has a markedly different fate than N remaining in the soil. Global evidence indicates that only approximately 50% of applied N fertilizer is captured by crops, and the remainder can cause pollution via runoff and gaseous emissions. This inefficiency is of global concern, and requires innovation based on improved understanding of which N forms are available for and ultimately taken up by crops. However, current soil analysis methods based on destructive soil sampling provide little insight into delivery and acquisition of N forms by roots. Here, we present the results of a study in sugarcane fields receiving different fertilizer regimes comparing soil N supply rates with potential root N uptake rates. We applied microdialysis, a novel technique for in situ quantification of soil nutrient fluxes, to measure flux rates of inorganic N and amino acid N, and analyzed N uptake capacities of sugarcane roots using 15N labelled tracers. We found that in fertilized sugarcane soils, fluxes of inorganic N exceed the uptake capacities of sugarcane roots by several orders of magnitude. Contrary, fluxes of organic N closely matched roots' uptake capacity. These results indicate root uptake capacity constrains plant acquisition of inorganic N. This mismatch between soil N supply and root N uptake capacity is a likely key driver for low N efficiency in the studied crop system. Our results also suggest that the relative contribution of inorganic N for plant nutrition may be overestimated when relying on soil extracts as indicators for root-available N, and organic N may contribute more to crop N supply than is currently assumed. Overall, we show a new approach for examining in situ N relations in soil in context of crop N physiology, which provides a new avenue towards tailoring N fertilizer supply to match the specific uptake abilities and N demand of crops over the growth

  6. Non-universal tracer diffusion in crowded media of non-inert obstacles.

    PubMed

    Ghosh, Surya K; Cherstvy, Andrey G; Metzler, Ralf

    2015-01-21

    We study the diffusion of a tracer particle, which moves in continuum space between a lattice of excluded volume, immobile non-inert obstacles. In particular, we analyse how the strength of the tracer-obstacle interactions and the volume occupancy of the crowders alter the diffusive motion of the tracer. From the details of partitioning of the tracer diffusion modes between trapping states when bound to obstacles and bulk diffusion, we examine the degree of localisation of the tracer in the lattice of crowders. We study the properties of the tracer diffusion in terms of the ensemble and time averaged mean squared displacements, the trapping time distributions, the amplitude variation of the time averaged mean squared displacements, and the non-Gaussianity parameter of the diffusing tracer. We conclude that tracer-obstacle adsorption and binding triggers a transient anomalous diffusion. From a very narrow spread of recorded individual time averaged trajectories we exclude continuous type random walk processes as the underlying physical model of the tracer diffusion in our system. For moderate tracer-crowder attraction the motion is found to be fully ergodic, while at stronger attraction strength a transient disparity between ensemble and time averaged mean squared displacements occurs. We also put our results into perspective with findings from experimental single-particle tracking and simulations of the diffusion of tagged tracers in dense crowded suspensions. Our results have implications for the diffusion, transport, and spreading of chemical components in highly crowded environments inside living cells and other structured liquids.

  7. Plutonium isotopes as tracers for ocean processes: a review.

    PubMed

    Lindahl, Patric; Lee, Sang-Han; Worsfold, Paul; Keith-Roach, Miranda

    2010-03-01

    Since the first nuclear weapons tests in the 1940s, pulsed inputs of plutonium isotopes have served as excellent tracers for understanding sources, pathways, dynamics and the fate of pollutants and particles in the marine environment. Due to the well-defined spatial and temporal inputs of Pu, the long half-lives of (240)Pu and (239)Pu and its unique chemical properties, Pu is a potential tracer for various physical and biogeochemical ocean processes, including circulation, sedimentation and biological productivity, and hence a means of assessing the impacts of global climate change. Due to the source dependency of the Pu isotopic signature, plutonium isotopes are beginning to be exploited as tools for the evaluation and improvement of regional and global ocean models that will enhance understanding of past and future changes in the oceans. This paper addresses the major sources of Pu and the physical and biogeochemical behaviour in the marine environment. Finally, the use of Pu isotopes as tracers for various oceanic processes (e.g. water mass transport, particle export, and sedimentation) is considered.

  8. Compact microfluidic device for rapid concentration of PET tracers

    PubMed Central

    Tseng, Wei-Yu; van Dam, R. Michael

    2015-01-01

    HPLC purification and reformulation of positron emission tomography (PET) tracers can lead to significant dilution of the final product, making it difficult to produce a sufficiently high radioactivity concentration for some applications (e.g. small animal imaging, in vitro assays, and labelling of proteins with prosthetic groups). This is especially true for molecules with lengthy or low-yield syntheses. Starting the synthesis with more radioactivity increases the final radioactivity concentration but increases hazards and complexity of handling. An alternative is to concentrate the final product by a process such as rotary evaporation prior to downstream use. Because a rotovap requires significant space within a hot cell that could be put to more productive use, we developed a compact microfluidic system for concentration of PET tracers. This system also provides advantages in terms of repeatability, interfacing and potential for automation. We present here the design and performance characterization of the system, and demonstrate the concentration of several tracers in aqueous-based HPLC mobile phases. PMID:24825578

  9. Using atmospheric tracers to reduce uncertainty in groundwater recharge areas.

    PubMed

    Starn, J Jeffrey; Bagtzoglou, Amvrossios C; Robbins, Gary A

    2010-01-01

    A Monte Carlo-based approach to assess uncertainty in recharge areas shows that incorporation of atmospheric tracer observations (in this case, tritium concentration) and prior information on model parameters leads to more precise predictions of recharge areas. Variance-covariance matrices, from model calibration and calculation of sensitivities, were used to generate parameter sets that account for parameter correlation and uncertainty. Constraining parameter sets to those that met acceptance criteria, which included a standard error criterion, did not appear to bias model results. Although the addition of atmospheric tracer observations and prior information produced similar changes in the extent of predicted recharge areas, prior information had the effect of increasing probabilities within the recharge area to a greater extent than atmospheric tracer observations. Uncertainty in the recharge area propagates into predictions that directly affect water quality, such as land cover in the recharge area associated with a well and the residence time associated with the well. Assessments of well vulnerability that depend on these factors should include an assessment of model parameter uncertainty. A formal simulation of parameter uncertainty can be used to delineate probabilistic recharge areas, and the results can be expressed in ways that can be useful to water-resource managers. Although no one model is the correct model, the results of multiple models can be evaluated in terms of the decision being made and the probability of a given outcome from each model.

  10. A tracer-kinetic field theory for medical imaging.

    PubMed

    Sourbron, Steven

    2014-04-01

    Dynamic imaging data are currently analyzed with a tracer-kinetic theory developed for individual time curves measured over whole organs. The assumption is that voxels represent isolated systems which all receive indicator through the same arterial inlet. This leads to well-known systematic errors, but also fails to exploit the spatial structure of the data. In this study, a more general theoretical framework is developed which makes full use of the specific structure of image data. The theory encodes the fact that voxels receive indicator from their immediate neighbors rather than from an upstream arterial input. This results in a tracer-kinetic field theory where the tissue parameters are functions of space which can be measured by analyzing the temporal and spatial patterns in the concentrations. The implications are evaluated through a number of field models for common tissue types. The key benefits of a tracer-kinetic field theory are that: 1) long-standing systematic errors can be corrected, specifically the issue of bolus dispersion and the contamination of large-vessel blood flow on tissue perfusion measurements; 2) additional tissue parameters can be measured that characterize convective or diffusive exchange between voxels; 3) the need to measure a separate arterial input function can be eliminated.

  11. An investigation of radial tracer flow in naturally fractured reservoirs

    SciTech Connect

    Jetzabeth, Ramirez-Sabag; Fernando, Samaniego V.; Jesus, Rivera R.; Fernando Rodriguez

    1991-01-01

    This study presents a general solution for the radial flow of tracers in naturally fractured reservoirs. Continuous and finite step injection of chemical and radioactive tracers are considered. The reservoir is treated as being composed of two regions: a mobile region where longitudinal dispersion and convection take place and a stagnant region where only diffusion and adsorption are allowed. Radioactive decay is considered in both regions. The model of this study is thoroughly compared to those previously presented in literature by Moench and Ogata, Tang et al., Chen et al., and Hsieh et al. The solution is numerically inverted by means of the Crump algorithm. A detailed validation of the model with respect to solutions previously presented and/or simplified physical conditions solutions (i.e., homogeneous case) or limit solutions (i.e., for short times) was carried out. The influence of various dimensionless parameters that enter into the solution was investigated. A discussion of results obtained through the Crump and Stehfest algorithm is presented, concluding that the Crump method provides more reliable tracer concentrations.

  12. Metal stable isotope signatures as tracers in environmental geochemistry.

    PubMed

    Wiederhold, Jan G

    2015-03-03

    The biogeochemical cycling of metals in natural systems is often accompanied by stable isotope fractionation which can now be measured due to recent analytical advances. In consequence, a new research field has emerged over the last two decades, complementing the traditional stable isotope systems (H, C, O, N, S) with many more elements across the periodic table (Li, B, Mg, Si, Cl, Ca, Ti, V, Cr, Fe, Ni, Cu, Zn, Ge, Se, Br, Sr, Mo, Ag, Cd, Sn, Sb, Te, Ba, W, Pt, Hg, Tl, U) which are being explored and potentially applicable as novel geochemical tracers. This review presents the application of metal stable isotopes as source and process tracers in environmental studies, in particular by using mixing and Rayleigh model approaches. The most important concepts of mass-dependent and mass-independent metal stable isotope fractionation are introduced, and the extent of natural isotopic variations for different elements is compared. A particular focus lies on a discussion of processes (redox transformations, complexation, sorption, precipitation, dissolution, evaporation, diffusion, biological cycling) which are able to induce metal stable isotope fractionation in environmental systems. Additionally, the usefulness and limitations of metal stable isotope signatures as tracers in environmental geochemistry are discussed and future perspectives presented.

  13. Development of perfluorocarbon tracer technology for underground leak location.

    PubMed

    Hassoun, S; McBride, T; Russell, D A

    2000-10-01

    A method has been developed for the atmospheric sampling and analysis of four perfluorocarbon tracer (PFT) compounds simultaneously at the parts per trillion (ppt) level. PFTs were pre-concentrated using adsorbent tube air sampling. Analysis was achieved by thermal desorption (TD) and gas chromatography (GC) with electron capture detection (ECD). Efficient separation of the PFTs from the other sample constituents was achieved by use of a capillary porous layer open tubular (PLOT) GC column without the need to cool the GC oven to sub-ambient temperatures using liquid coolants (M. de Bortoli and E. Pecchio, J. High Resolut. Chromatogr., 1985, 8, 422) or for a catalytic destruction step to remove interferents (T. W. D'Ottavio, R. W. Goodrich and R. N. Dietz, Environ. Sci. Technol., 1986, 20, 100). Results from test field trials with two volatile PFTs that were buried to simulate an underground leaking cable were successful. The PFTs were detected above ground level to pinpoint the leak position. The highest tracer concentrations were detected within 1 m of the simulated leak positions 2 days after tracer burial. The developed technology was applied to an oil leaking high voltage electricity cable. One PFT was added to the cable oil which enabled detection of the oil leak to within 3 m. The reported method has many advantages over currently used leak detection methods and could, in the future, be applied to the detection of underground leaks in a variety of cables and pipes.

  14. Evaluation of new stratospheric age tracers and SF6

    NASA Astrophysics Data System (ADS)

    Laube, J. C.; Gallacher, E.; Oram, D.; Boenisch, H.; Engel, A.; Fraser, P. J.; Röckmann, T.; Sturges, W. T.

    2015-12-01

    Sulphur hexafluoride (SF6) is a very long-lived, potent greenhouse gas. Its abundances continue to increase in the atmosphere. Due to its inert behaviour it has also been extensively used as a tracer of transport in the ocean, the troposphere and the stratosphere. We here combine long-term tropospheric records obtained from the Cape Grim Baseline station, Tasmania, with stratospheric data from high-altitude aircraft and balloon campaigns. We then assess the novel use of several alternative transport tracers (e.g. C2F6, C3F8 and HFC-23) in the stratosphere. The results indicate good suitability for some of these gases in terms of their inertness, tropospheric growth rates and measurement precisions. In addition we and compare the derived mean ages to those obtained from SF6 and find indications for the possibility of the existence of a stratospheric SF6 sink. The latter finding would also imply that the total atmospheric lifetime of SF6 is substantially shorter than previously believed, with further implications for its use as a transport tracer in the stratosphere.

  15. Radioisotope tracer study in a sludge hygienization research irradiator (SHRI).

    PubMed

    Pant, H J; Thýn, J; Zitný, R; Bhatt, B C

    2001-01-01

    A radioisotope tracer study has been carried out in a batch type sludge hygienization research irradiator with flow from top to bottom, the objective being to measure flow rate, circulation and mixing times and to investigate the hydrodynamic behaviour of the irradiator for identifying the cause(s) of malfunction. A stimulus-response technique with NH4(82)Br as a tracer was used to measure the above parameters. Experiments were carried out at three different flow rates, i.e 1.0, 0.64 and 0.33 m3/min. Three combined models based on a set of differential equations are proposed and used to simulate the measured tracer concentration curves. The obtained parameters were used to estimate dead volume and analyse hydrodynamic behaviour of the irradiator. The nonlinear regression problem of model parameter estimation was solved using the Marquardt-Levenberg method. The measured flow rate was found to be in good agreement with the values shown by the flow meter. The circulation times were found to be half of the mixing times. A simple approach for estimation of dose based on a known vertical dose-rate profile inside the irradiator is presented. About one-fourth of the volume of the irradiator was found to be dead at lower flow rates and this decreased with increase in flow rate. At higher flow rates, a semi stagnant volume was found with slow exchange of flow between the active and dead volumes.

  16. Radioactive tracers facilitate stimulation job evaluation. Part 1

    SciTech Connect

    Fisher, K.; Walker, R.; Dunleavy, R.; Woodroof, B.; Crabb, H.

    1995-02-01

    Logging tools can now quantify multiple isotopes, including the volume of individual isotopes present and their radial position away from the well bore. In conjunction with those improvements, tracers have been developed that eliminate wash off effects of conventional tracers. By precisely locating the presence and concentration of traced proppant at the well bore, better evaluations can be made of vertical and radial proppant distribution near the well bore and fracture aperture width. A comprehensive study of 98 wells with 136 fracture stages in four different basins has been completed. Each stage was traced and logged. Spectral gamma ray logs were compared with conventional openhole logs, sonic stress logs where available, and cased hole logs such as cement bond and production logs. This data was then compared on a well-by-well basis with the fracture design program, post treatment stimulation reports and production history. Several trends were identified while building this massive stimulation evaluation database. Problems that potentially could be solved using tracer technology are: fracture height greater than design; unstimulated perforation sets within a stage; understimulated pay intervals.

  17. Entropically induced asymmetric passage times of charged tracers across corrugated channels

    SciTech Connect

    Malgaretti, Paolo; Pagonabarraga, Ignacio; Miguel Rubi, J.

    2016-01-21

    We analyze the diffusion of charged and neutral tracers suspended in an electrolyte embedded in a channel of varying cross section. Making use of systematic approximations, the diffusion equation governing the motion of tracers is mapped into an effective 1D equation describing the dynamics along the longitudinal axis of the channel where its varying-section is encoded as an effective entropic potential. This simplified approach allows us to characterize tracer diffusion under generic confinement by measuring their mean first passage time (MFPT). In particular, we show that the interplay between geometrical confinement and electrostatic interactions strongly affect the MFTP of tracers across corrugated channels hence leading to alternative means to control tracers translocation across charged pores. Finally, our results show that the MFPTs of a charged tracer in opposite directions along an asymmetric channel may differ We expect our results to be relevant for biological as well synthetic devices whose dynamics is controlled by the detection of diluted tracers.

  18. In-Situ Characterization of Dense Non-Aqueous Phase Liquids Using Partitioning Tracers

    SciTech Connect

    Gary A. Pope; Daene C. McKinney; Akhil Datta Gupta; Richard E. Jackson; Minquan Jin

    2000-03-20

    Majors advances have been made during the past three years in our research on interwell partitioning tracers tests (PITTs). These advances include (1) progress on the inverse problem of how to estimate the three-dimensional distribution of NAPL in aquifers from the tracer data, (2) the first ever partitioning tracer experiments in dual porosity media, (3) the first modeling of partitioning tracers in dual porosity media (4) experiments with complex NAPLs such as coal tar, (5) the development of an accurate and simple method to predict partition coefficients using the equivalent alkane carbon number approach, (6) partitioning tracer experiments in large model aquifers with permeability layers, (7) the first ever analysis of partitioning tracer data to estimate the change in composition of a NAPL before and after remediation (8) the first ever analysis of partitioning tracer data after a field demonstration of surfactant foam to remediate NAPL and (9) experiments at elevated temperatures .

  19. Glial activation colocalizes with structural abnormalities in amyotrophic lateral sclerosis

    PubMed Central

    Alshikho, Mohamad J.; Zürcher, Nicole R.; Loggia, Marco L.; Cernasov, Paul; Chonde, Daniel B.; Izquierdo Garcia, David; Yasek, Julia E.; Akeju, Oluwaseun; Catana, Ciprian; Rosen, Bruce R.; Cudkowicz, Merit E.

    2016-01-01

    Objective: In this cross-sectional study, we aimed to evaluate brain structural abnormalities in relation to glial activation in the same cohort of participants. Methods: Ten individuals with amyotrophic lateral sclerosis (ALS) and 10 matched healthy controls underwent brain imaging using integrated MR/PET and the radioligand [11C]-PBR28. Diagnosis history and clinical assessments including Upper Motor Neuron Burden Scale (UMNB) were obtained from patients with ALS. Diffusion tensor imaging (DTI) analyses including tract-based spatial statistics and tractography were applied. DTI metrics including fractional anisotropy (FA) and diffusivities (mean, axial, and radial) were measured in regions of interest. Cortical thickness was assessed using surface-based analysis. The locations of structural changes, measured by DTI and the areas of cortical thinning, were compared to regional glial activation measured by relative [11C]-PBR28 uptake. Results: In this cohort of individuals with ALS, reduced FA and cortical thinning colocalized with regions demonstrating higher radioligand binding. [11C]-PBR28 binding in the left motor cortex was correlated with FA (r = −0.68, p < 0.05) and cortical thickness (r = −0.75, p < 0.05). UMNB was correlated with glial activation (r = +0.75, p < 0.05), FA (r = −0.77, p < 0.05), and cortical thickness (r = −0.75, p < 0.05) in the motor cortex. Conclusions: Increased uptake of the glial marker [11C]-PBR28 colocalizes with changes in FA and cortical thinning. This suggests a link between disease mechanisms (gliosis and inflammation) and structural changes (cortical thinning and white and gray matter changes). In this multimodal neuroimaging work, we provide an in vivo model to investigate the pathogenesis of ALS. PMID:27837005

  20. Uptake of HBR on ice films

    SciTech Connect

    Chu, L.T.

    1996-10-01

    Uptake is an initial step occurring in heterogeneous atmospheric reactions. It is a key step necessary to understand the reaction mechanism of heterogeneous reactions occurring on polar stratospheric clouds (PSCs) surfaces. The uptake of HBr on ice films has been investigated in a fast flow reactor and the amount is determined by using a differentially pumped quadrupole mass spectrometer combined with a pulsed molecular beam sampling method. A larger uptake and the formation of hydrobromic acid hydrates were observed in the uptake experiments. The effect of the ice film temperatures, HBr pressures, and ice film morphology on the uptake is studied. We will compare the uptake of HCl, HBr and HI on the basis of our recent studies. The results will lead to an advanced understanding of heterogeneous bromine reactions on PSCs.