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Sample records for short-lived alpha particle-emitting

  1. Radioimmunotherapy with alpha-particle emitting radionuclides.

    PubMed

    Zalutsky, M R; Pozzi, O R

    2004-12-01

    An important consideration in the development of effective strategies for radioimmunotherapy is the nature of the radiation emitted by the radionuclide. Radionuclides decaying by the emission of alpha-particles offer the possibility of matching the cell specific reactivity of monoclonal antibodies with radiation with a range of only a few cell diameters. Furthermore, alpha-particles have important biological advantages compared with external beam radiation and beta-particles including a higher biological effectiveness, which is nearly independent of oxygen concentration, dose rate and cell cycle position. In this review, the clinical settings most likely to benefit from alpha-particle radioimmunotherapy will be discussed. The current status of preclinical and clinical research with antibodies labeled with 3 promising alpha-particle emitting radionuclides - (213)Bi, (225)Ac, and (211)At - also will be summarized. PMID:15640792

  2. Intense alpha-particle emitting crystallites in uranium mill wastes

    USGS Publications Warehouse

    Landa, E.R.; Stieff, L.R.; Germani, M.S.; Tanner, A.B.; Evans, J.R.

    1994-01-01

    Nuclear emulsion microscopy has demonstrated the presence of small, intense ??-particle emitting crystallites in laboratory-produced tailings derived from the sulfuric acid milling of uranium ores. The ??-particle activity is associated with the isotope pair 210Pb 210Po, and the host mineral appears to be PbSO4 occurring as inclusions in gypsum laths. These particles represent potential inhalation hazards at uranium mill tailings disposal areas. ?? 1994.

  3. Quality factors for alpha particles emitted in tissue

    NASA Technical Reports Server (NTRS)

    Borak, Thomas B.; Chatterjee, A. (Principal Investigator)

    2002-01-01

    A concept of a mean or dose averaged quality factor was defined in ICRP Publication 26 using relationships for quality factor as a function of LET. The concept of radiation weighting factors, wR, was introduced in ICRP Publication 60 in 1990. These are meant to be generalized factors that modify absorbed dose to reflect the risk of stochastic effects as a function of the quality of the radiation incident on the body or emitted by radioactivity within the body. The values of wr are equal to 20 for all alpha particles externally or internally emitted. This note compares the dose averaged quality factor for alpha particles originating in tissue using the old and revised recommendations for quality factor as a function of LET. The dose averaged quality factor never exceeds 20 using the old recommendations and is never less than 20 with the revised recommendations.

  4. Enhanced retention of the alpha-particle-emitting daughters of Actinium-225 by liposome carriers.

    PubMed

    Sofou, Stavroula; Kappel, Barry J; Jaggi, Jaspreet S; McDevitt, Michael R; Scheinberg, David A; Sgouros, George

    2007-01-01

    Targeted alpha-particle emitters hold great promise as therapeutics for micrometastatic disease. Because of their high energy deposition and short range, tumor targeted alpha-particles can result in high cancer-cell killing with minimal normal-tissue irradiation. Actinium-225 is a potential generator for alpha-particle therapy: it decays with a 10-day half-life and generates three alpha-particle-emitting daughters. Retention of (225)Ac daughters at the target increases efficacy; escape and distribution throughout the body increases toxicity. During circulation, molecular carriers conjugated to (225)Ac cannot retain any of the daughters. We previously proposed liposomal encapsulation of (225)Ac to retain the daughters, whose retention was shown to be liposome-size dependent. However, daughter retention was lower than expected: 22% of theoretical maximum decreasing to 14%, partially due to the binding of (225)Ac to the phospholipid membrane. In this study, Multivesicular liposomes (MUVELs) composed of different phospholipids were developed to increase daughter retention. MUVELs are large liposomes with entrapped smaller lipid-vesicles containing (225)Ac. PEGylated MUVELs stably retained over time 98% of encapsulated (225)Ac. Retention of (213)Bi, the last daughter, was 31% of the theoretical maximum retention of (213)Bi for the liposome sizes studied. MUVELs were conjugated to an anti-HER2/neu antibody (immunolabeled MUVELs) and were evaluated in vitro with SKOV3-NMP2 ovarian cancer cells, exhibiting significant cellular internalization (83%). This work demonstrates that immunolabeled MUVELs might be able to deliver higher fractions of generated alpha-particles per targeted (225)Ac compared to the relative fractions of alpha-particles delivered by (225)Ac-labeled molecular carriers. PMID:17935286

  5. Thorium and actinium polyphosphonate compounds as bone-seeking alpha particle-emitting agents.

    PubMed

    Henriksen, Gjermund; Bruland, Oyvind S; Larsen, Roy H

    2004-01-01

    The present study explores the use of alpha-particle-emitting, bone-seeking agents as candidates for targeted radiotherapy. Actinium and thorium 1,4,7,10 tetraazacyclododecane N,N',N'',N''' 1,4,7,10-tetra(methylene) phosphonic acid (DOTMP) and thorium-diethylene triamine N,N',N'' penta(methylene) phosphonic acid (DTMP) were prepared and their biodistribution evaluated in conventional Balb/C mice at four hours after injection. All three bone-seeking agents showed a high uptake in bone and a low uptake in soft tissues. Among the soft tissue organs, only kidney had a relatively high uptake. The femur/kidney ratios for 227Th-DTMP, 228-Ac-DOTMP and 227Th-DOTMP were 14.2, 7.6 and 6.0, respectively. A higher liver uptake of 228Ac-DOTMP was seen than for 227Th-DTMP and 227Th-DOTMP. This suggests that some demetallation of the 228Ac-DOTMP complex had occurred. The results indicate that 225Ac-DOTMP, 227Th-DOTMP and 227Th-DTMP have promising properties as potential therapeutic bone-seeking agents. PMID:15015582

  6. Renal tubulointerstitial changes after internal irradiation with alpha-particle-emitting actinium daughters.

    PubMed

    Jaggi, Jaspreet Singh; Seshan, Surya V; McDevitt, Michael R; LaPerle, Krista; Sgouros, George; Scheinberg, David A

    2005-09-01

    The effect of external gamma irradiation on the kidneys is well described. However, the mechanisms of radiation nephropathy as a consequence of targeted radionuclide therapies are poorly understood. The functional and morphologic changes were studied chronologically (from 10 to 40 wk) in mouse kidneys after injection with an actinium-225 (225Ac) nanogenerator, a molecular-sized, antibody-targeted, in vivo generator of alpha-particle-emitting elements. Renal irradiation from free, radioactive daughters of 225Ac led to time-dependent reduction in renal function manifesting as increase in blood urea nitrogen. The histopathologic changes corresponded with the decline in renal function. Glomerular, tubular, and endothelial cell nuclear pleomorphism and focal tubular cell injury, lysis, and karyorrhexis were observed as early as 10 wk. Progressive thinning of the cortex as a result of widespread tubulolysis, collapsed tubules, glomerular crowding, decrease in glomerular cellularity, interstitial inflammation, and an elevated juxtaglomerular cell count were noted at 20 to 30 wk after treatment. By 35 to 40 wk, regeneration of simplified tubules with tubular atrophy and loss with focal, mild interstitial fibrosis had occurred. A lower juxtaglomerular cell count with focal cytoplasmic vacuolization, suggesting increased degranulation, was also observed in this period. A focal increase in tubular and interstitial cell TGF-beta1 expression starting at 20 wk, peaking at 25 wk, and later declining in intensity with mild increase in the extracellular matrix deposition was noticed. These findings suggest that internally delivered alpha-particle irradiation-induced loss of tubular epithelial cells triggers a chain of adaptive changes that result in progressive renal parenchymal damage accompanied by a loss of renal function. These findings are dissimilar to those seen after gamma or beta irradiation of kidneys. PMID:15987754

  7. Treatment of solid tumors by interstitial release of recoiling short-lived alpha emitters

    NASA Astrophysics Data System (ADS)

    Arazi, L.; Cooks, T.; Schmidt, M.; Keisari, Y.; Kelson, I.

    2007-08-01

    A new method utilizing alpha particles to treat solid tumors is presented. Tumors are treated with interstitial radioactive sources which continually release short-lived alpha emitting atoms from their surface. The atoms disperse inside the tumor, delivering a high dose through their alpha decays. We implement this scheme using thin wire sources impregnated with 224Ra, which release by recoil 220Rn, 216Po and 212Pb atoms. This work aims to demonstrate the feasibility of our method by measuring the activity patterns of the released radionuclides in experimental tumors. Sources carrying 224Ra activities in the range 10-130 kBq were used in experiments on murine squamous cell carcinoma tumors. These included gamma spectroscopy of the dissected tumors and major organs, Fuji-plate autoradiography of histological tumor sections and tissue damage detection by Hematoxylin-Eosin staining. The measurements focused on 212Pb and 212Bi. The 220Rn/216Po distribution was treated theoretically using a simple diffusion model. A simplified scheme was used to convert measured 212Pb activities to absorbed dose estimates. Both physical and histological measurements confirmed the formation of a 5-7 mm diameter necrotic region receiving a therapeutic alpha-particle dose around the source. The necrotic regions shape closely corresponded to the measured activity patterns. 212Pb was found to leave the tumor through the blood at a rate which decreased with tumor mass. Our results suggest that the proposed method, termed DART (diffusing alpha-emitters radiation therapy), may potentially be useful for the treatment of human patients.

  8. Alpha-Particle Emitting 213Bi-Anti-EGFR Immunoconjugates Eradicate Tumor Cells Independent of Oxygenation

    PubMed Central

    Gaertner, Florian C.; Bruchertseifer, Frank; Morgenstern, Alfred; Essler, Markus; Senekowitsch-Schmidtke, Reingard

    2013-01-01

    Hypoxia is a central problem in tumor treatment because hypoxic cells are less sensitive to chemo- and radiotherapy than normoxic cells. Radioresistance of hypoxic tumor cells is due to reduced sensitivity towards low Linear Energy Transfer (LET) radiation. High LET α-emitters are thought to eradicate tumor cells independent of cellular oxygenation. Therefore, the aim of this study was to demonstrate that cell-bound α-particle emitting 213Bi immunoconjugates kill hypoxic and normoxic CAL33 tumor cells with identical efficiency. For that purpose CAL33 cells were incubated with 213Bi-anti-EGFR-MAb or irradiated with photons with a nominal energy of 6 MeV both under hypoxic and normoxic conditions. Oxygenation of cells was checked via the hypoxia-associated marker HIF-1α. Survival of cells was analysed using the clonogenic assay. Cell viability was monitored with the WST colorimetric assay. Results were evaluated statistically using a t-test and a Generalized Linear Mixed Model (GLMM). Survival and viability of CAL33 cells decreased both after incubation with increasing 213Bi-anti-EGFR-MAb activity concentrations (9.25 kBq/ml–1.48 MBq/ml) and irradiation with increasing doses of photons (0.5–12 Gy). Following photon irradiation survival and viability of normoxic cells were significantly lower than those of hypoxic cells at all doses analysed. In contrast, cell death induced by 213Bi-anti-EGFR-MAb turned out to be independent of cellular oxygenation. These results demonstrate that α-particle emitting 213Bi-immunoconjugates eradicate hypoxic tumor cells as effective as normoxic cells. Therefore, 213Bi-radioimmunotherapy seems to be an appropriate strategy for treatment of hypoxic tumors. PMID:23724085

  9. Bismuth-212-labeled anti-Tac monoclonal antibody: alpha-particle-emitting radionuclides as modalities for radioimmunotherapy

    SciTech Connect

    Kozak, R.W.; Atcher, R.W.; Gansow, O.A.; Friedman, A.M.; Hines, J.J.; Waldmann, T.A.

    1986-01-01

    Anti-Tac, a monoclonal antibody directed to the human interleukin 2 (IL-2) receptor, has been successfully conjugated to the alpha-particle-emitting radionuclide bismuth-212 by use of a bifunctional ligand, the isobutylcarboxycarbonic anhydride of diethylenetriaminepentaacetic acid. The physical properties of 212Bi are appropriate for radioimmunotherapy in that it has a short half-life, deposits its high energy over a short distance, and can be obtained in large quantities from a radium generator. Antibody specific activities of 1-40 microCi/microgram (1 Ci = 37 GBq) were achieved. Specificity of the 212Bi-labeled anti-Tac was demonstrated for the IL-2 receptor-positive adult T-cell leukemia line HUT-102B2 by protein synthesis inhibition and clonogenic assays. Activity levels of 0.5 microCi or the equivalent of 12 rad/ml of alpha radiation targeted by anti-Tac eliminated greater than 98% the proliferative capabilities of HUT-102B2 cells with more modest effects on IL-2 receptor-negative cell lines. Specific cytotoxicity was blocked by excess unlabeled anti-Tac but not by human IgG. In addition, an irrelevant control monoclonal antibody of the same isotype labeled with 212Bi was unable to target alpha radiation to cell lines. Therefore, 212Bi-labeled anti-Tac is a potentially effective and specific immunocytotoxic reagent for the elimination of IL-2 receptor-positive cells. These experiments thus provide the scientific basis for use of alpha-particle-emitting radionuclides in immunotherapy.

  10. Engineered Modular Recombinant Transporters: Application of New Platform for Targeted Radiotherapeutic Agents to {alpha}-Particle Emitting {sup 211}At

    SciTech Connect

    Rosenkranz, Andrey A.; Vaidyanathan, Ganesan; Pozzi, Oscar R.; Lunin, Vladimir G.; Zalutsky, Michael R. Sobolev, Alexander S.

    2008-09-01

    Purpose: To generate and evaluate a modular recombinant transporter (MRT) for targeting {sup 211}At to cancer cells overexpressing the epidermal growth factor receptor (EGFR). Methods and Materials: The MRT was produced with four functional modules: (1) human epidermal growth factor as the internalizable ligand, (2) the optimized nuclear localization sequence of simian vacuolating virus 40 (SV40) large T-antigen, (3) a translocation domain of diphtheria toxin as an endosomolytic module, and (4) the Escherichia coli hemoglobin-like protein (HMP) as a carrier module. MRT was labeled using N-succinimidyl 3-[{sup 211}At]astato-5-guanidinomethylbenzoate (SAGMB), its {sup 125}I analogue SGMIB, or with {sup 131}I using Iodogen. Binding, internalization, and clonogenic assays were performed with EGFR-expressing A431, D247 MG, and U87MG.wtEGFR human cancer cell lines. Results: The affinity of SGMIB-MRT binding to A431 cells, determined by Scatchard analysis, was 22 nM, comparable to that measured before labeling. The binding of SGMIB-MRT and its internalization by A431 cancer cells was 96% and 99% EGFR specific, respectively. Paired label assays demonstrated that compared with Iodogen-labeled MRT, SGMIB-MRT and SAGMB-MRT exhibited more than threefold greater peak levels and durations of intracellular retention of activity. SAGMB-MRT was 10-20 times more cytotoxic than [{sup 211}At]astatide for all three cell lines. Conclusion: The results of this study have demonstrated the initial proof of principle for the MRT approach for designing targeted {alpha}-particle emitting radiotherapeutic agents. The high cytotoxicity of SAGMB-MRT for cancer cells overexpressing EGFR suggests that this {sup 211}At-labeled conjugate has promise for the treatment of malignancies, such as glioma, which overexpress this receptor.

  11. Nucleon-Alpha Particle Disequilibrium and Short-Lived r-Process Radioactivities

    NASA Technical Reports Server (NTRS)

    Meyer, B. S.; Clayton, D. D.; Chellapilla, S.; The, L.-S.

    2002-01-01

    r-Process yields can be extremely sensitive to expansion parameters when a persistent disequilibrium between free nucleons and alpha particles is present. This may provide a natural scenario for understanding the variation of heavy and light r-process isotopes in different r-process events. Additional information is contained in the original extended abstract.

  12. Nucleon-Alpha Particle Disequilibrium and Short-Lived r-Process Radioactivities

    NASA Astrophysics Data System (ADS)

    Meyer, B. S.; Clayton, D. D.; Chellapilla, S.; The, L.-S.

    2002-03-01

    r-Process yields can be extremely sensitive to expansion parameters when a persistent disequilibrium between free nucleons and alpha particles is present. This may provide a natural scenario for understanding the variation of heavy and light r-process isotopes in different r-process events.

  13. Hit rates and radiation doses to nuclei of bone lining cells from alpha-particle-emitting radionuclides

    NASA Technical Reports Server (NTRS)

    Polig, E.; Jee, W. S.; Kruglikov, I. L.

    1992-01-01

    Factors relating the local concentration of a bone-seeking alpha-particle emitter to the mean hit rate have been determined for nuclei of bone lining cells using a Monte Carlo procedure. Cell nuclei were approximated by oblate spheroids with dimensions and location taken from a previous histomorphometric study. The Monte Carlo simulation is applicable for planar and diffuse labels at plane or cylindrical bone surfaces. Additionally, the mean nuclear dose per hit, the dose mean per hit, the mean track segment length and its second moment, the percentage of stoppers, and the frequency distribution of the dose have been determined. Some basic features of the hit statistics for bone lining cells have been outlined, and the consequences of existing standards of radiation protection with regard to the hit frequency to cell nuclei are discussed.

  14. First In Vivo Evaluation of Liposome-encapsulated 223Ra as a Potential Alpha-particle-emitting Cancer Therapeutic Agent

    SciTech Connect

    Jonasdottir, Thora J.; Fisher, Darrell R.; Borrebaek, Jorgen; Bruland, Oyvind S.; Larsen, Roy H.

    2006-09-13

    Liposomes carrying chemotherapeutics have had some success in cancer treatment and may be suitable carriers for therapeutic radionuclides. This study was designed to evaluate the biodistribution of and to estimate the radiation doses from the alpha emitter 223Ra loaded into pegylated liposomes in selected tissues. 223Ra was encapsulated in pegylated liposomal doxorubicin by ionophore-mediated loading. The biodistribution of liposomal 223Ra was compared to free cationic 223Ra in Balb/C mice. We showed that liposomal 223 Ra circulated in the blood with an initial half-time in excess of 24 hours, which agreed well with that reported for liposomal doxorubicin in rodents, while the blood half-time of cationic 223Ra was considerably less than one hour. When liposomal 223 Ra was catabolized, the released 223Ra was either excreted or taken up in the skeleton. This skeletal uptake increased up to 14 days after treatment, but did not reach the level seen with free 223Ra. Pre-treatment with non-radioactive liposomal doxorubicin 4 days in advance lessened the liver uptake of liposomal 223 Ra. Dose estimates showed that the spleen, followed by bone surfaces, received the highest absorbed doses. Liposomal 223 Ra was relatively stable in vivo and may have potential for radionuclide therapy and combination therapy with chemotherapeutic agents.

  15. Treatment of HER2-Expressing Breast Cancer and Ovarian Cancer Cells With Alpha Particle-Emitting {sup 227}Th-Trastuzumab

    SciTech Connect

    Heyerdahl, Helen; Krogh, Cecilie; Borrebaek, Jorgen; Larsen, Asmund; Dahle, Jostein

    2011-02-01

    Purpose: To evaluate the cytotoxic effects of low-dose-rate alpha particle-emitting radioimmunoconjugate {sup 227}Th-p-isothiocyanato-benzyl-DOTA-trastuzumab ({sup 227}Th-trastuzumab [where DOTA is 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]) internalized by breast and ovarian cancer cell lines in order to assess the potential of {sup 227}Th-trastuzumab as a therapeutic agent against metastatic cancers that overexpress the HER2 oncogene. Methods and Materials: Clonogenic survival and cell growth rates of breast cancer cells treated with {sup 227}Th-trastuzumab were compared with rates of cells treated with nonbinding {sup 227}Th-rituximab, cold trastuzumab, and X-radiation. Cell growth experiments were also performed with ovarian cancer cells. Cell-associated radioactivity was measured at several time points, and the mean radiation dose to cells was calculated. Results: SKBR-3 cells got 50% of the mean absorbed radiation dose from internalized activity and 50% from cell surface-bound activity, while BT-474 and SKOV-3 cells got 75% radiation dose from internalized activity and 25% from cell surface-bound activity. Incubation of breast cancer cells with 2.5 kBq/ml {sup 227}Th-trastuzumab for 1 h at 4{sup o}C, followed by washing, resulted in mean absorbed radiation doses of 2 to 2.5 Gy. A dose-dependent inhibition of cell growth and an increase in apoptosis were induced in all cell lines. Conclusions: Clinically relevant activity concentrations of {sup 227}Th-trastuzumab induced a specific cytotoxic effect in three HER2-expressing cell lines. The cytotoxic effect of {sup 227}Th-trastuzumab was higher than that of single-dose X-radiation (relative biological effectiveness = 1.2). These results warrant further studies of treatment of breast cancer and ovarian cancer with {sup 227}Th-trastuzumab.

  16. [Short-lived disorders].

    PubMed

    Artigas-Pallares, Josep

    2012-02-29

    Over the years, most of the mental disorders that are dealt with in everyday clinical practice have changed not only their names but also their conceptualisation. Furthermore, as some disorders disappear or are forgotten, others come into being. Seen from a historical perspective and unlike many of the diseases included within classical medicine, it can be stated that one of the basic characteristics of mental disorders is their short-lived presence in the scientific literature. In this study we analyse the causes underlying the transitory nature of mental disorders. The disappearance of a disorder or the modification of how it is conceptualised may be linked to several different motives. Sometimes they may be due to an evolution of the construct, as a result of new findings. On other occasions the disorder falls into disuse owing to the weakness of the theoretical construct or the clinical research upholding it. Lastly, because the Diagnostic and Statistical Manual of Mental Disorders and the International Classification of Diseases require updates that incorporate new contributions and correct faults in the current model, they give rise to new denominations and definitions in mental disorders. This article analyses these three situations and offers an illustrative example in each case. PMID:22374762

  17. Labeling monoclonal antibodies and F(ab')2 fragments with the alpha-particle-emitting nuclide astatine-211: preservation of immunoreactivity and in vivo localizing capacity.

    PubMed Central

    Zalutsky, M R; Garg, P K; Friedman, H S; Bigner, D D

    1989-01-01

    alpha-Particles such as those emitted by 211At may be advantageous for radioimmunotherapy since they are radiation of high linear energy transfer, depositing high energy over a short distance. Here we describe a strategy for labeling monoclonal antibodies and F(ab')2 fragments with 211At by means of the bifunctional reagent N-succinimidyl 3-(trimethylstannyl)benzoate. An intact antibody, 81C6, and the F(ab')2 fragment of Me1-14 (both reactive with human gliomas) were labeled with 211At in high yield and with a specific activity of up to 4 mCi/mg in a time frame compatible with the 7.2-hr half-life of 211At. Quantitative in vivo binding assays demonstrated that radioastatination was accomplished with maintenance of high specific binding and affinity. Comparison of the biodistribution of 211At-labeled Me1-14 F(ab')2 to that of a nonspecific antibody fragment labeled with 211At and 131I in athymic mice bearing D-54 MG human glioma xenografts demonstrated selective and specific targeting of 211At-labeled antibody in this human tumor model. PMID:2476813

  18. Short-Lived Climate Pollution

    NASA Astrophysics Data System (ADS)

    Pierrehumbert, R. T.

    2014-05-01

    Although carbon dioxide emissions are by far the most important mediator of anthropogenic climate disruption, a number of shorter-lived substances with atmospheric lifetimes of under a few decades also contribute significantly to the radiative forcing that drives climate change. In recent years, the argument that early and aggressive mitigation of the emission of these substances or their precursors forms an essential part of any climate protection strategy has gained a considerable following. There is often an implication that such control can in some way make up for the current inaction on carbon dioxide emissions. The prime targets for mitigation, known collectively as short-lived climate pollution (SLCP), are methane, hydrofluo-rocarbons, black carbon, and ozone. A re-examination of the issues shows that the benefits of early SLCP mitigation have been greatly exaggerated, largely because of inadequacies in the methodologies used to compare the climate effects of short-lived substances with those of CO2, which causes nearly irreversible climate change persisting millennia after emissions cease. Eventual mitigation of SLCP can make a useful contribution to climate protection, but there is little to be gained by implementing SLCP mitigation before stringent carbon dioxide controls are in place and have caused annual emissions to approach zero. Any earlier implementation of SLCP mitigation that substitutes to any significant extent for carbon dioxide mitigation will lead to a climate irreversibly warmer than will a strategy with delayed SLCP mitigation. SLCP mitigation does not buy time for implementation of stringent controls on CO2 emissions.

  19. Search for short lived neutral particle in the 15.1 MeV isovector transition of 12C

    NASA Astrophysics Data System (ADS)

    Datar, V. M.; Fortier, S.; Gales, S.; Hourani, E.; Langevin, H.; Maison, J. M.; Massolo, C. P.

    1988-01-01

    We report a search for a short lived neutral particle ? emitted in the decay of the 15.1 MeV J?(T)=1+(1) state in 12C. The experiment is sensitive to ?-->e+e- decays and finds no evidence for such a particle. We set upper limits on ??/?? for mean lifetimes between ~10-13 and ~10-8 sec and in the mass range 1.02-2.5 MeV.

  20. Skylab short-lived event alert program

    NASA Technical Reports Server (NTRS)

    Citron, R. A.

    1974-01-01

    During the three manned Skylab missions, the Center for Short-Lived Phenomena (CSLP) reported a total of 39 significant events to the Johnson Space Center (JSC) as part of the Skylab Short-Lived Event Alert Program. The telegraphed daily status reports included the names and locations of the events, the track number and revolution number during which the event could be observed, the time (GMT) to within plus or minus 2 sec when Skylab was closest to the event area, and the light condition (daylight or darkness) at that time and place. The messages sent to JSC during the Skylab 4 mission also included information pertaining to ground-truth studies and observations being conducted on the events. Photographic priorities were assigned for each event.

  1. Alchemy with short-lived radionuclides

    SciTech Connect

    Rubio, F.F.; Finn, R.D.; Gilson, A.J.

    1981-04-01

    A variety of short-lived radionuclides are produced and subsequently incorporated into radiopharmaceutical compounds in the radionuclide production program currently being conducted at the Cyclotron Facility of Mount Sinai Medical Center. The recovery of high specific activity oxygen-15 labelled water prepared by means of an inexpensive system operating in conjunction with an on-line radiogas target routinely utilized for oxygen-15 labelled carbon dioxide studies is currently receiving particular attention.

  2. Counting Particles Emitted by Stratospheric Aircraft and Measuring Size of Particles Emitted by Stratospheric Aircraft

    NASA Technical Reports Server (NTRS)

    Wilson, James Charles

    1994-01-01

    There were two principal objectives of the cooperative agreement between NASA and the University of Denver. The first goal was to modify the design of the ER-2 condensation nuclei counter (CNC) so that the effective lower detection limit would be improved at high altitudes. This improvement was sought because, in the instrument used prior to 1993, diffusion losses prevented the smallest detectable particles from reaching the detection volume of the instrument during operation at low pressure. Therefore, in spite of the sensor's ability to detect particles as small as 0.008 microns in diameter, many of these particles were lost in transport to the sensing region and were not counted. Most of the particles emitted by aircraft are smaller than 0.1 micron in diameter. At the start date of this work, May 1990, continuous sizing techniques available on the ER-2 were only capable of detecting particles larger than 0.17 micron. Thus, the second objective of this work was to evaluate candidate sizing techniques in an effort to gain additional information concerning the size of particles emitted by aircraft.

  3. Sinusoidal Regge Oscillations from Short Lived Resonances

    NASA Astrophysics Data System (ADS)

    Sokolovski, D.; Felfli, Z.; Msezane, A. Z.

    2007-06-01

    It is well known that a resonance with a large angular life can produce sharp Breit-Wigner peaks in the energy dependence of integral cross sections [1,2]. Here we show that a short-lived resonance whose angular life is of order of one full rotation may produce a different kind of contribution to the integral cross section. This contribution has a sinousoidal form and its frequency is determined by the rotational constant of the complex. As one of the examples, we analyze the Regge oscillations observed in numerical simulations of the F+H2(v=0,j=0,φ=0) ->FH(v'=2,j'=0,φ'=0) + H reaction. In particular, we show that these oscillations are produced by two overlapping resonances located near the transition state and the van der Waals well, respectively [3]. [1] J. H. Macek, et al., Phys. Rev. Lett., 93, 183202, (2004). [2] Z. Felfli et al., J. Phys. B 39, L353 (2006) [3] D. Sokolovski, D. De Fazio, S. Cavalli and V. Aquilanti, J. Chem. Phys. (2007) (submitted).

  4. Studies of images of short lived events using ERTS data

    NASA Technical Reports Server (NTRS)

    Deutschman, W. A. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. The program to study short-lived events with the ERTS-1 satellite has evaluated 97 events reported by the Center for Short-Lived Phenomena. Forty-eight of these events were listed as candidates for ERTS-1 coverage and 8 of these were considered significant enough to immediately alert the ERTS operation staff by telephone. Studies of the images received from six events indicate that useful data on short-lived events can be obtained from ERTS-1 that would be difficult or impossible to obtain by other methods.

  5. Soot and short-lived pollutants provide political opportunity

    NASA Astrophysics Data System (ADS)

    Victor, David G.; Zaelke, Durwood; Ramanathan, Veerabhadran

    2015-09-01

    Cutting levels of soot and other short-lived pollutants delivers tangible benefits and helps governments to build confidence that collective action on climate change is feasible. After the Paris climate meeting this December, actually reducing these pollutants will be essential to the credibility of the diplomatic process.

  6. Short-lived positron emitter labeled radiotracers - present status

    SciTech Connect

    Fowler, J.S.; Wolf, A.P.

    1982-01-01

    The preparation of labelled compounds is important for the application of positron emission transaxial tomography (PETT) in biomedical sciences. This paper describes problems and progress in the synthesis of short-lived positron emitter (/sup 11/C, /sup 18/F, /sup 13/N) labelled tracers for PETT. Synthesis of labelled sugars, amino acids, and neurotransmitter receptors (pimozide and spiroperidol tagged with /sup 11/C) is discussed in particular. (DLC)

  7. Extension of NCRP 129 to short-lived radionuclides.

    PubMed

    Arno, M G; Kercher, J R; Cederwall, R T; Loosmore, G A

    2004-08-01

    NCRP 129 contains dose conversion factors for 200 radionuclides that allow one to estimate the maximum dose to an individual based on the concentration of the radionuclide in the soil and the way in which the land is used. The methodology of NCRP 129 has been extended to be applicable to 28 common short-lived radionuclides and their progeny, and dose conversion factors were obtained for these radionuclides. In addition to applying the NCRP 129 calculational methodology to these radionuclides, holdup times from harvest or slaughter until consumption have been incorporated into the decay correction equations used to determine the maximum annual dose due to the significance of the holdup time with respect to the dose from short-lived radionuclides. These holdup times were included in the Monte Carlo sampling regimen used in NCRP 129. A test using emission rates proportional to those of the Chernobyl event indicated that areas of high dose, where rainout occurs, more than doubled in areas where short-lived radionuclides from this study were included. PMID:15257214

  8. Production of α-particle emitting 211At using 45 MeV α-beam

    NASA Astrophysics Data System (ADS)

    Kim, Gyehong; Chun, Kwonsoo; Park, Sung Ho; Kim, Byungil

    2014-06-01

    Among the α-particle emitting radionuclides, 211At is considered to be a promising radionuclide for targeted cancer therapy due to its decay properties. The range of alpha particles produced by the decay of 211At are less than 70 µm in water with a linear energy transfer between 100 and 130 keV µm-1, which are about the maximum relative biological effectiveness for heavy ions. It is important to note that at the present time, only a few of cyclotrons routinely produce 211At. The direct production method is based on the nuclear reactions 209Bi(α,2n)211At. Production of the radionuclide 211At was carried out using the MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). To ensure high beam current, the α-beam was extracted with an initial energy of 45 MeV, which was degraded to obtain the appropriate α-beam energy. The calculations of beam energy degradation were performed utilizing the MCNPX. Alumina-baked targets were prepared by heating the bismuth metal powder onto a circular cavity in a furnace. When using an Eα, av of 29.17 MeV, the very small contribution of 210At confirms the right choice of the irradiation energy to obtain a pure production of 211At isotope.

  9. Laser trapping of short-lived radioactive isotopes

    SciTech Connect

    Lu, Z.; Bowers, C.; Freedman, S.J.; Fujikawa, B.K.; Mortara, J.L.; Shang, S. ); Coulter, K.P.; Young, L. )

    1994-06-13

    We describe an experiment which demonstrates the feasibility of trapping significant quantities of short-lived radioactive atoms with laser light. A thermal beam of 22.5 sec half-life [sup 21]Na atoms was produced on-line at the LBL 88[prime][prime] Cyclotron. After decelerating the beam using a Zeeman-tuned slowing technique we stored about 4[times]10[sup 3] [sup 21]Na atoms in a magneto-optical trap. The number of trapped atoms is large enough to be used in experimental studies of the beta decay of [sup 21]Na. The basic method can be adapted for other rare isotopes.

  10. Magnetic Resonance of short-lived negative ions

    NASA Astrophysics Data System (ADS)

    Toader, Emil; Stalder, Kenneth; Graham, Bill

    2003-10-01

    Here we present the possibility of creating short-lived (labile or exotic) negative ions, from the scattering of free electrons and polarized molecules in a discharge. In the interaction the electrons do not loose energy. Their mechanism of formation, structure and stability are completely different from those corresponding to stable negative ions. A classical analysis, based on an effective potential with a centrifugal term and a polarized term, shows that low energy electrons can orbit for some time around a polarized molecule. A quantum mechanics model shows that such labile negative ions can be in states that are characterized by the molecular quantum mechanics numbers K (rotational) and J (total), and the electron quantum numbers l (orbital) and j (total). The molecule is in the magnetic field created by the rotating electron, and can change its magnetic moment, so the short-lived negative ion can make the transitions between the different rotational states. Each transition corresponds to a variation of the magnetic energy, so we can have a doublet transition both in emission and absorption, at radio-frequencies from 1 to 150 MHz in deuterium and oxygen . The dispersion curves are specific to each polarized molecule and the transition frequencies can be measured using resonant detection methods.

  11. Near-term climate mitigation by short-lived forcers

    PubMed Central

    Smith, Steven J.; Mizrahi, Andrew

    2013-01-01

    Emissions reductions focused on anthropogenic climate-forcing agents with relatively short atmospheric lifetimes, such as methane (CH4) and black carbon, have been suggested as a strategy to reduce the rate of climate change over the next several decades. We find that reductions of methane and black carbon would likely have only a modest impact on near-term global climate warming. Even with maximally feasible reductions phased in from 2015 to 2035, global mean temperatures in 2050 would be reduced by 0.16 C, with a range of 0.040.35 C because of uncertainties in carbonaceous aerosol emissions and aerosol forcing per unit of emissions. The high end of this range is only possible if total historical aerosol forcing is relatively small. More realistic emission reductions would likely provide an even smaller climate benefit. We find that the climate benefit from reductions in short-lived forcing agents are smaller than previously estimated. These near-term climate benefits of targeted reductions in short-lived forcers are not substantially different in magnitude from the benefits from a comprehensive climate policy. PMID:23940357

  12. Near-Term Climate Mitigation by Short-Lived Forcers

    SciTech Connect

    Smith, Steven J.; Mizrahi, Andrew H.

    2013-08-12

    Emissions reductions focused on anthropogenic climate forcing agents with relatively short atmospheric lifetimes such as methane (CH4) and black carbon (BC) have been suggested as a strategy to reduce the rate of climate change over the next several decades. We find that reductions of methane and BC would likely have only a modest impact on near-term climate warming. Even with maximally feasible reductions phased in from 2015 to 2035, global mean temperatures in 2050 are reduced by 0.16 °C, with an uncertainty range of 0.04-0.36°C, with the high end of this range only possible if total historical aerosol forcing is small. More realistic mitigation scenarios would likely provide a smaller climate benefit. The climate benefits from targeted reductions in short-lived forcing agents are smaller than previously estimated and are not substantially different in magnitude from the benefits due to a comprehensive climate policy.

  13. Nucleosynthesis of Short-lived Radioactivities in Massive Stars

    NASA Technical Reports Server (NTRS)

    Meyer, B. S.

    2004-01-01

    A leading model for the source of many of the short-lived radioactivities in the early solar nebula is direct incorporation from a massive star [1]. A recent and promising incarnation of this model includes an injection mass cut, which is a boundary between the stellar ejecta that become incorporated into the solar cloud and those ejecta that do not [2-4]. This model also includes a delay time between ejection from the star and incorporation into early solar system solid bodies. While largely successful, this model requires further validation and comparison against data. Such evaluation becomes easier if we have a better sense of the nature of the synthesis of the various radioactivities in the star. That is the goal of this brief abstract.

  14. SHORT-LIVED RADIO BURSTS FROM THE CRAB PULSAR

    SciTech Connect

    Crossley, J. H.; Eilek, J. A.; Hankins, T. H.; Kern, J. S.

    2010-10-20

    Our high-time-resolution observations reveal that individual main pulses from the Crab pulsar contain one or more short-lived microbursts. Both the energy and duration of bursts measured above 1 GHz can vary dramatically in less than a millisecond. These fluctuations are too rapid to be caused by propagation through turbulence in the Crab Nebula or in the interstellar medium; they must be intrinsic to the radio emission process in the pulsar. The mean duration of a burst varies with frequency as {nu}{sup -2}, significantly different from the broadening caused by interstellar scattering. We compare the properties of the bursts to some simple models of microstructure in the radio emission region.

  15. Feasibility of short-lived radionuclide production at Fermilab

    SciTech Connect

    Ten Haken, R.K.; Awschalom, M.; Rosenberg, I.

    1982-04-29

    The feasibility of establishing a facility for short-lived radionuclide production hinges on the availability of the Fermilab injector linac and on how such a program would fit in with the primary mission of the laboratory. The linac is available 168 hours per week except for scheduled maintenance, which typically does not exceed one to two shifts per week, and HEP requirements. The laboratory may be reluctant to make a commitment for the routine production of SLRs however, due to its understanding of the requirements for reliable scheduled delivery of targets. But, the laboratory is also quite interested in establishing industrial liaisons. It would be willing to explore feasible industrial proposals, especially with regards to developing a research-type facility where the technology and methods developed at Fermilab could be utilized elsewhere.

  16. Detection Of Short-Lived Particles Using Holography

    NASA Astrophysics Data System (ADS)

    Haridas, P.; Hafen, E.; Pless, I.; Harton, J.; Dixit, S.; Goloskie, D.; Benton, S.

    1985-08-01

    Vertex detectors with good spatial resolution are ideal devices for the detection of short-lived particles (mean lifetime > 10-13 s; mean distance traveled before decay- um) produced in high energy interactions. The bubble chamber equipped with high resolution photography is one such vertex detector. However, improving the resolution in photography results in a very rapid decrease of the depth of field, thereby rendering most of the chamber optically inaccessible. Using holography instead of photography remedies this problem by decoupling resolution and depth of field. This paper reports on our recent work in the use of a two-beam holographic technique for a large Freon bubble chamber (80 cm in diameter and 100 cm deep). The results reported here are for a full-scale setup in air with test targets to simulate bubble chamber tracks and in some cases a full-scale 28 cm thick glass plate to simulate chamber windows. This bubble chamber is the vertex detector for a hybrid spectrometer system that will be used for two of our forthcoming experiments at the Fermi National Accelerator Laboratory: the first to search for the short-lived charmed particles and the second to establish the existence of the T neutrino by observing the decay of the T lepton. We demonstrate that a 30 resolution can be achieved throughout the entire volume of the chamber. Specific details pertinent to achieving this resolution are also discussed. We also report on the construction of a semiautomated high precision measuring apparatus that will be used to scan and measure bubble chamber holograms.

  17. Short-lived Isotopes from a Close-by AGB Star Triggering the Protosolar Nebula

    NASA Astrophysics Data System (ADS)

    Gallino, R.; Busso, M.; Wasserburg, G. J.; Straniero, O.

    The presence of short-lived isotopes in the early solar system, in particular 26Al, 41Ca, 60Fe, and 107Pd, point to a close-by and fresh nucleosynthesis source, possibly triggering the collapse of the protosolar nebula. We present the results of nucleosynthesis calculations based on an AGB polluting hypothesis. A general concordance of the predicted yields of the above radioactivities relative to 26Al can be obtained in the case of an intermediate mass AGB star with hot bottom burning in the envelope (thus producing 26Al), and mixing through a series of third dredge-up episodes a fraction of the C-rich and s-processed material from the He intershell with the extended envelope. Polution of the protosolar nebula with freshly synthesized material may derive from the efficient winds of the AGB star. In AGB stars, the s-process nucleosynthesis occurs both during the maximum phase of every thermal runaway, driven by the partial activation of the 22Ne(alpha,n)25Mg reaction, and in the interpulse phase, where the 13C nuclei are fully consumed in radiative conditions by the activation of the 13C(alpha,n)16O reaction. We have used different prescriptions for the amount of the 13C nuclei present in the intershell. A minimum amount of 13C is naturally expected in the ashes of H-shell burning. Possible formation of an extra "13C-pocket" derives from the injection of a small amount of protons from the envelope into the 12C-rich intershell during any third dredge-up episode, when the H-shell is inactivated. Prediction for other short-lived, 36Cl, 135Cs, and 205Pb, are given. General consequences for the pollution of the protosolar nebula with newly synthesized stable isotopes from the AGB winds are outlined. The origin of other detected short-lived nuclei, in particular 53Mn, 129I, and 182Hf, which cannot come from an AGB source, is analysed. The alternative trigger hypothesis by a close-by Supernova is discussed.

  18. Beta Decay Studies of Short Lived Barium Isotopes

    NASA Astrophysics Data System (ADS)

    Bendall, Charles Skipwith

    The half-lives and relative intensities of several short lived neutron rich isotopes, with atomic numbers between 54 and 57, produced in the spontaneous fission of californium-252 were determined. This was accomplished from the study of the time variation of the K X-ray yields of these isotopes. A transport system which allowed us to study isotopes with half-lives less than 10 seconds was developed. Mass assignments were made by comparing the experimental values of the half-lives with known values. A beta K X-ray coincidence technique was used to obtain the barium beta spectrum in coincidence with lanthanum K X -rays. A Kurie plot was performed on the spectrum to determine the beta groups. The probable origin of each beta group was determined through a comparison of the relative intensities of the isotopes and beta groups. Four beta groups probably from the decay of Ba-145 were revealed. The end point energies of these beta groups are 3870 (+OR-) 432 keV, 2772 (+OR-) 112 keV, 1894 (+OR-) 58 keV, and 746 (+OR-) 38 keV. The three lowest energy groups have not been observed before.

  19. Quantifying Short-Lived Events in Multistate Ionic Current Measurements

    PubMed Central

    2015-01-01

    We developed a generalized technique to characterize polymer–nanopore interactions via single channel ionic current measurements. Physical interactions between analytes, such as DNA, proteins, or synthetic polymers, and a nanopore cause multiple discrete states in the current. We modeled the transitions of the current to individual states with an equivalent electrical circuit, which allowed us to describe the system response. This enabled the estimation of short-lived states that are presently not characterized by existing analysis techniques. Our approach considerably improves the range and resolution of single-molecule characterization with nanopores. For example, we characterized the residence times of synthetic polymers that are three times shorter than those estimated with existing algorithms. Because the molecule’s residence time follows an exponential distribution, we recover nearly 20-fold more events per unit time that can be used for analysis. Furthermore, the measurement range was extended from 11 monomers to as few as 8. Finally, we applied this technique to recover a known sequence of single-stranded DNA from previously published ion channel recordings, identifying discrete current states with subpicoampere resolution. PMID:24397836

  20. Convective transport of very short lived bromocarbons to the stratosphere

    NASA Astrophysics Data System (ADS)

    Liang, Q.; Atlas, E.; Blake, D.; Dorf, M.; Pfeilsticker, K.; Schauffler, S.

    2014-06-01

    We use the NASA Goddard Earth Observing System (GEOS) Chemistry Climate Model (GEOSCCM) to quantify the contribution of the two most important brominated very short lived substances (VSLSs), bromoform (CHBr3) and dibromomethane (CH2Br2), to stratospheric bromine and its sensitivity to convection strength. Model simulations suggest that the most active transport of VSLSs from the marine boundary layer through the tropopause occurs over the tropical Indian Ocean, the tropical western Pacific, and off the Pacific coast of Mexico. Together, convective lofting of CHBr3 and CH2Br2 and their degradation products supplies ~8 ppt total bromine to the base of the tropical tropopause layer (TTL, ~150 hPa), similar to the amount of VSLS organic bromine available in the marine boundary layer (~7.8-8.4 ppt) in the active convective lofting regions mentioned above. Of the total ~8 ppt VSLS bromine that enters the base of the TTL at ~150 hPa, half is in the form of organic source gases and half in the form of inorganic product gases. Only a small portion (<10%) of the VSLS-originated bromine is removed via wet scavenging in the TTL before reaching the lower stratosphere. On average, globally, CHBr3 and CH2Br2 together contribute ~7.7 pptv to the present-day inorganic bromine in the stratosphere. However, varying model deep-convection strength between maximum (strongest) and minimum (weakest) convection conditions can introduce a ~2.6 pptv uncertainty in the contribution of VSLSs to inorganic bromine in the stratosphere (BryVSLS). Contrary to conventional wisdom, the minimum convection condition leads to a larger BryVSLS as the reduced scavenging in soluble product gases, and thus a significant increase in product gas injection (2-3 ppt), greatly exceeds the relatively minor decrease in source gas injection (a few 10ths ppt).

  1. Efficiency of short-lived halogens at influencing climate through depletion of stratospheric ozone

    NASA Astrophysics Data System (ADS)

    Hossaini, R.; Chipperfield, M. P.; Montzka, S. A.; Rap, A.; Dhomse, S.; Feng, W.

    2015-03-01

    Halogens released from long-lived anthropogenic substances, such as chlorofluorocarbons, are the principal cause of recent depletion of stratospheric ozone, a greenhouse gas. Recent observations show that very short-lived substances, with lifetimes generally under six months, are also an important source of stratospheric halogens. Short-lived bromine substances are produced naturally by seaweed and phytoplankton, whereas short-lived chlorine substances are primarily anthropogenic. Here we used a chemical transport model to quantify the depletion of ozone in the lower stratosphere from short-lived halogen substances, and a radiative transfer model to quantify the radiative effects of that ozone depletion. According to our simulations, ozone loss from short-lived substances had a radiative effect nearly half that from long-lived halocarbons in 2011 and, since pre-industrial times, has contributed a total of about -0.02 W m-2 to global radiative forcing. We find natural short-lived bromine substances exert a 3.6 times larger ozone radiative effect than long-lived halocarbons, normalized by halogen content, and show atmospheric levels of dichloromethane, a short-lived chlorine substance not controlled by the Montreal Protocol, are rapidly increasing. We conclude that potential further significant increases in the atmospheric abundance of short-lived halogen substances, through changing natural processes or continued anthropogenic emissions, could be important for future climate.

  2. Studies of images of short-lived events using ERTS data

    NASA Technical Reports Server (NTRS)

    Deutschman, W. A. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Significant results are the continued detection of short-lived events. The following have been detected and analyzed: forest fires, oil spills, vegetation damage, volcanoes, storm ridges, and earthquakes. It is hoped that the Mississippi River flood scenes will arrive shortly and then floods be added to the list of identified short-lived events.

  3. Studies of images of short-lived events using ERTS data

    NASA Technical Reports Server (NTRS)

    Deutschman, W. A. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Of significance are the continued detection and analysis of such short-lived events as forest fires, oil spills, vegetation damage, volcanoes, storm ridges, and earthquakes.

  4. Age-dependent inhalation doses to members of the public from indoor short-lived radon progeny.

    PubMed

    Brudecki, K; Li, W B; Meisenberg, O; Tschiersch, J; Hoeschen, C; Oeh, U

    2014-08-01

    The main contribution of radiation dose to the human lungs from natural exposure originates from short-lived radon progeny. In the present work, the inhalation doses from indoor short-lived radon progeny, i.e., (218)Po, (214)Pb, (214)Bi, and (214)Po, to different age groups of members of the public were calculated. In the calculations, the age-dependent systemic biokinetic models of polonium, bismuth, and lead published by the International Commission on Radiological Protection (ICRP) were adopted. In addition, the ICRP human respiratory tract and gastrointestinal tract models were applied to determine the deposition fractions in different regions of the lungs during inhalation and exhalation, and the absorption fractions of radon progeny in the alimentary tract. Based on the calculated contribution of each progeny to equivalent dose and effective dose, the dose conversion factor was estimated, taking into account the unattached fraction of aerosols, attached aerosols in the nucleation, accumulation and coarse modes, and the potential alpha energy concentration fraction in indoor air. It turned out that for each progeny, the equivalent doses to extrathoracic airways and the lungs are greater than those to other organs. The contribution of (214)Po to effective dose is much smaller compared to that of the other short-lived radon progeny and can thus be neglected in the dose assessment. In fact, 90 % of the effective dose from short-lived radon progeny arises from (214)Pb and (214)Bi, while the rest is from (218)Po. The dose conversion factors obtained in the present study are 17 and 18 mSv per working level month (WLM) for adult female and male, respectively. This compares to values ranging from 6 to 20 mSv WLM(-1) calculated by other investigators. The dose coefficients of each radon progeny calculated in the present study can be used to estimate the radiation doses for the population, especially for small children and women, in specific regions of the world exposed to radon progeny by measuring their concentrations, aerosol sizes, and unattached fractions. PMID:24831865

  5. Production of a short-lived filament by a surge. [in solar atmosphere

    NASA Technical Reports Server (NTRS)

    Zirin, H.

    1976-01-01

    An unusual solar event is investigated in which a short-lived cloud, very much like a filament, was formed by ejecta from a large surge. The temporal evolution of this surge is described, and evidence is presented which indicates that the short-lived cloud was a bona fide filament. The energetics of this event and the mass of the surge are estimated from radio and X-ray data obtained at the onset.

  6. Mineralogical characterization of ambient fine/ultrafine particles emitted from Xuanwei C1 coal combustion

    NASA Astrophysics Data System (ADS)

    Lu, Senlin; Hao, Xiaojie; Liu, Dingyu; Wang, Qiangxiang; Zhang, Wenchao; Liu, Pinwei; Zhang, Rongci; Yu, Shang; Pan, Ruiqi; Wu, Minghong; Yonemochi, Shinich; Wang, Qingyue

    2016-03-01

    Nano-quartz in Xuanwei coal, the uppermost Permian (C1) coal deposited in the northwest of Yuanan, China, has been regarded as one of factors which caused high lung cancer incidence in the local residents. However, mineralogical characterization of the fine/ultrafine particles emitted from Xuanwei coal combustion has not previously been studied. In this study, PM1 and ultrafine particles emitted from Xuanwei coal combustion were sampled. Chemical elements in the ambient particles were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), and mineralogical characterization of these ambient particles was investigated using scanning electronic microscopy (SEM/EDX) and transmission electronic microscopy, coupled with energy-dispersive spectroscopy (TEM/EDX). Our results showed that the size distribution of mineral particles from the coal combustion emissions ranged from 20 to 200 nm. Si-containing particles and Fe-containing particles accounted for 50.7% of the 150 individual particles measured, suggesting that these two types of particles were major minerals in the ambient particles generally. The nano-mineral particles were identified as quartz (SiO2) and gypsum (CaSO4) based on their crystal parameters and chemical elements. Additionally, there also existed unidentified nano-minerals. Armed with these data, toxicity assessments of the nano-minerals will be carried out in a future study.

  7. Impact of Reducing Short-Lived Air Pollutants on Atmospheric Composition and Climate

    NASA Astrophysics Data System (ADS)

    Naik, V.; Horowitz, L. W.; Fiore, A. M.; Levy, H.

    2010-12-01

    Most studies to date have quantified the impact of short-lived air pollutants on climate in terms of radiative forcing, where radiative forcing is calculated based on changes in forcing agent distributions induced by emission perturbations simulated in a chemistry-transport model (CTM). Here, we employ the GFDL AM3 model to investigate the impact of a change in the emissions of short-lived air pollutants on the coupled chemistry-climate system (including stratospheric and tropospheric chemistry, and cloud-aerosol interactions). We present results from two simulations conducted in support of the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The base case simulation uses prescribed mean 1981-2000 sea surface temperatures and sea ice cover taken from the historical simulations conducted for the Coupled Model Intercomparison Project 5 (CMIP5) in support of the IPCC-AR5. Concentrations of well-mixed greenhouse gases, ozone depleting substances, and emissions of short-lived pollutants are for the year 2000. The perturbation simulation uses the same configuration except the short-lived pollutant emissions are reduced to 1860 values (77% decrease for NOx, 54% decrease for CO, 70% NMVOCs, 95% SO2, 58% BC and 35% OC). Our initial analysis indicates that the troposphere and stratosphere respond in opposite ways to the reduction in short-lived pollutants. While tropospheric ozone burden decreases (by 18% or 64 Tg on an annual average), stratospheric ozone increases, particularly over the poles. This pre-industrial to present change in tropospheric ozone is somewhat smaller than prior CTM estimates, suggesting an important influence from stratosphere-troposphere interactions. We will examine the differences in atmospheric circulation, temperature and precipitation, stratosphere-troposphere exchange, oxidizing capacity and aerosol distributions in the two simulations, with the goal of advancing our understanding of the role of short-lived pollutants in the coupled chemistry-climate system.

  8. Advanced short-lived nuclide NAA with application in the life sciences.

    PubMed

    Papadopoulos, N N; Tsagas, N F

    1994-01-01

    A new technique for short-lived nuclide activation analysis has been developed that compensates the rapid radioactive decay during the counting period by simultaneous approach of the sample holder to the detector with a mechanical device, permitting prolongation of the counting time and reduction of the required complementary cyclic activation to avoid sample container damage. The operation of the analytical system is automated by a programmable logic controller (PLC). This improvement of short-lived nuclide activation analysis, providing a high throughput, is important in biological and environmental research, where often a large number of samples has to be analyzed for sufficient sampling statistics. PMID:7710819

  9. Radioimmunotherapy with alpha-emitting nuclides.

    PubMed

    McDevitt, M R; Sgouros, G; Finn, R D; Humm, J L; Jurcic, J G; Larson, S M; Scheinberg, D A

    1998-09-01

    This review discusses the application of alpha particle-emitting radionuclides in targeted radioimmunotherapy. It will outline the production and chemistry of astatine-211, bismuth-212, lead-212, actinium-225, bismuth-213, fermium-255, radium-223 and terbium-149, which at present are the most promising alpha-emitting isotopes available for human clinical use. The selective cytotoxicity offered by alpha particle-emitting radioimmunoconstructs is due to the high linear energy transfer and short particle path length of these radionuclides. Based upon the pharmacokinetics of alpha particle-emitting radioimmunoconstructs, both stochastic and conventional dosimetric methodology is discussed, as is the preclinical and initial clinical use of these radionuclides conjugated to monoclonal antibodies for the treatment of human neoplasia. PMID:9724387

  10. Processes regulating short-lived species in the tropical tropopause layer

    NASA Astrophysics Data System (ADS)

    Gettelman, A.; Lauritzen, P. H.; Park, M.; Kay, J. E.

    2009-07-01

    A one-dimensional model of vertical transport in the tropical tropopause layer (TTL) is developed. The model uses vertical advection, a convective source, and a chemical sink to simulate the profiles of very short lived substances in the TTL. The model simulates evanescent profiles of short-lived hydrocarbon species observed by satellite and is also used to simulate short-lived bromine species. Tracers with chemical lifetimes of 25 days or longer have significant concentrations in the stratosphere, and vertical advection is critical. Convection is important up to its peak altitude, nearly 19 km. Convection dominates the distribution of species with lifetimes less than 25 days. The annual cycle of species with lifetimes longer than 25 days is governed primarily by the variations of vertical velocity, not convection. This is particularly true for carbon monoxide, where a seasonal cycle in the lower stratosphere of the right phase is produced without variations in tropospheric emissions. An analysis of critical short-lived bromine species (CH2Br2 and CHBr3) indicates that substantial amounts of these tracers may get advected into the lower stratosphere as source gases at 18 km, and are estimated to contribute 2.8 pptv (1.1-4.1) to stratospheric bromine.

  11. Processes regulating short-lived species in the tropical tropopause layer

    NASA Astrophysics Data System (ADS)

    Gettelman, A.; Kay, J. E.; Lauritzen, P.; Park, M.

    2009-12-01

    A one-dimensional model of vertical transport in the tropical tropopause layer (TTL) is presented to better understand the processes controlling short lived species in the TTL. The model simulates evanescent profiles of short-lived hydrocarbon species observed by satellite and is also used to simulate short-lived bromine species. Results indicate that tracers with chemical lifetimes of 25 days or longer have significant concentrations in the stratosphere, and vertical advection is critical. Convection is important up to its peak altitude, nearly 19 km. Convection dominates the distribution of species with lifetimes less than 25 days. The annual cycle of species with lifetimes longer than 25 days is governed primarily by the variations of vertical velocity, not convection. This is particularly true for carbon monoxide, where a seasonal cycle in the lower stratosphere of the right phase is produced without variations in tropospheric emissions. An analysis of critical short-lived bromine species (CH2Br2 and CHBr3) indicates that substantial amounts of these tracers may get advected into the lower stratosphere as source gases at 18 km, and contribute significantly to stratospheric bromine.

  12. Synthesis of radiopharmaceuticals containing short-lived radionuclides. Progress report, March 1, 1985-February 26, 1986

    SciTech Connect

    Kabalka, G.W.

    1985-09-01

    Methods for the rapid introduction of short-lived radionuclides into agents for use in diagnostic nuclear medicine are reported. Methods to synthesize radioiodinated fatty acids, lipids, and amphetamine derivatives are described. New routes for the introduction of bromine-77, chlorine-34m, and carbon-11 into agents of interest are elaborated. 46 refs.

  13. Synthesis of radiopharmaceuticals containing short-lived radionuclides. Comprehensive report, March 1, 1980-February 26, 1986

    SciTech Connect

    Kabalka, G.W.

    1985-09-01

    New methods for the rapid introduction of short-lived radionuclides into agents for use in diagnostic nuclear medicine are reported. Among the new syntheses reported are those for /sup 123/I-labeled fatty acids and steroids, for /sup 11/C-labeled alcohols, for /sup 13/N-labeled amines, and for /sup 15/O-labeled alcohols. 33 refs.

  14. Precision mass measurements of short-lived nuclides for nuclear structure studies at TITAN

    NASA Astrophysics Data System (ADS)

    Chaudhuri, A.; Andreoiu, C.; Brunner, T.; Chowdhury, U.; Ettenauer, S.; Frekers, D.; Gallant, A. T.; Grossheim, A.; Gwinner, G.; Klawitter, R.; Kwiatkowski, A. A.; Leach, K. G.; Lennarz, A.; Lunney, D.; Macdonald, T. D.; Schultz, B. E.; Seeraji, S.; Simon, M. C.; Simon, V. V.; Dilling, J.

    2014-03-01

    TITAN (TRIUMF's Ion Trap for Atomic and Nuclear science) at TRIUMF's rare isotope beam facility ISAC is an advanced Penning trap based mass spectrometer dedicated to precise and accurate mass determinations. An overview of TITAN, the measurement technique and a highlight of recent mass measurements of the short-lived nuclides important to the nuclear structure program at TITAN are presented.

  15. Experimental Measurements of Short-Lived Fission Products from Uranium, Neptunium, Plutonium and Americium

    SciTech Connect

    Metz, Lori A.; Payne, Rosara F.; Friese, Judah I.; Greenwood, Lawrence R.; Kephart, Jeremy D.; Pierson, Bruce D.

    2009-11-01

    Fission yields are especially well characterized for long-lived fission products. Modeling techniques incorporate numerous assumptions and can be used to deduce information about the distribution of short-lived fission products. This work is an attempt to gather experimental (model-independent) data on the short-lived fission products. Fissile isotopes of uranium, neptunium, plutonium and americium were irradiated under pulse conditions at the Washington State University 1 MW TRIGA reactor to achieve ~108 fissions. The samples were placed on a HPGe (high purity germanium) detector to begin counting in less than 3 minutes post irradiation. The samples were counted for various time intervals ranging from 5 minutes to 1 hour. The data was then analyzed to determine which radionuclides could be quantified and compared to the published fission yield data.

  16. Efficient adsorption of waterborne short-lived radon decay products by glass fiber filters.

    PubMed

    von Philipsborn, H

    1997-02-01

    Glass fiber filters of a certain brand were found to be very efficient (retention > 95%) for adsorption of short-lived radon decay products during filtration of water. Carrier-free samples are obtained in a convenient geometry for efficient gross beta counting. Adsorption of "hot atoms" is not disturbed by the presence of "cold" lead ions. Approximate radioactive equilibrium between radon and its short-lived decay products may or may not exist in water at the source, but does exist after 3 h in PET bottles. These bottles are shown to be gas-tight for radon. Calibration of activity concentration in Bq L(-1) (radon gas concentration approximately equilibrium equivalent radon concentration) was performed by several standard procedures. Limit of detection is 2 Bq L(-1) within 10 min (total time) or 10 Bq L(-1) within 5 min for a net signal of 5 times standard deviation. PMID:9003713

  17. A 3-D model for assessing ozone depletion potentials of short-lived fumigants

    SciTech Connect

    Olaguer, E.P.

    1995-12-31

    Scientific and regulatory assessments of stratospheric ozone depletion have relied on 2-D, 1-D and even 0-D atmospheric models. These tools are at best applicable to long-lived compounds and are inappropriate for chemicals with life-times of the order of one year or less. This paper will discuss the capabilities of an efficient 3-D meteorological-chemical model for simulating the stratospheric impacts of short-lived fumigants and their atmospheric degradation products. The model has the unique feature of simultaneously coupling radiative, chemical and dynamical processes in the stratosphere and troposphere. It can be used to derive policy indices such as ozone depletion potential and global warming potential, and to assess perturbations in atmospheric composition, radiative forcing and surface ultraviolet flux due to short-lived anthropogenic compounds.

  18. Characterization of short-lived intermediates produced during replication of baculovirus DNA.

    PubMed

    Mikhailov, Victor S; Rohrmann, George F

    2009-10-01

    In this report the short-lived DNA replication intermediates produced in both uninfected and Autographa californica multiple nucleopolyhedrovirus (AcMNPV) infected Spodoptera frugiperda cells were characterized. The methods used included pulse-labeling of DNA in permiabilized cells, treatment of nascent DNA with Mung bean nuclease, and electrophoresis in neutral and alkaline agarose gels. In contrast to uninfected cells that produced a population of small DNA fragments of about 200bp, a population of heterogeneous fragments of up to 5kb with an average size of 1-2kb derived randomly from the virus genome was identified as the short-lived intermediates produced during AcMNPV replication. The intermediates likely include Okazaki fragments derived from the lagging strands in viral replication forks as well as fragments produced during the recombination-dependent replication. PMID:19560496

  19. Emission Channeling with Short-Lived Isotopes (EC-SLI) at CERN's ISOLDE Facility

    NASA Astrophysics Data System (ADS)

    Wahl, U.; Correia, J. G.; Costa, A.; David-Bosne, E.; Pereira, L. M. C.; Amorim, L. M.; Augustyns, V.; Temst, K.; Vantomme, A.; da Silva, M. R.; Silva, D. J.; Araújo, J. P.; Miranda, P.; Bharuth-Ram, K.

    2015-11-01

    We give an overview on the historical development and current program for lattice location studies at CERN's ISOLDE facility, where the EC-SLI (Emission Channeling with Short-Lived Isotopes) collaboration maintains several setups for this type of experiments. We illustrate that the three most decisive factors for the success of the technique are access to facilities producing radioactive isotopes, position-sensitive detectors for the emitted decay particles, and reliable simulation codes which allow for quantitative analysis.

  20. M-Track: detecting short-lived protein-protein interactions in vivo

    PubMed Central

    Zuzuarregui, Aurora; Kupka, Thomas; Bhatt, Bhumika; Dohnal, Ilse; Mudrak, Ingrid; Friedmann, Christina; Schüchner, Stefan; Frohner, Ingrid E.; Ammerer, Gustav; Ogris, Egon

    2012-01-01

    We developed a protein-proximity assay in yeast based on fusing a histone lysine methyltransferase onto a bait and its substrate onto a prey. Upon binding, the prey is stably methylated and detected by methylation-specific antibodies. We applied this approach to detect varying interaction affinities among proteins in a mitogen-activated protein kinase pathway and to detect short-lived interactions between protein phosphatase 2A and its substrates that have so far escaped direct detection. PMID:22581371

  1. Miss Piggy, a californium-252 fission fragment source as a generator of short-lived radionuclides

    NASA Astrophysics Data System (ADS)

    Düllmann, Ch. E.; Eichler, B.; Eichler, R.; Gäggeler, H. W.; Jost, D. T.; Kindler, U.; Piguet, D.; Soverna, S.; Thörle, P.; Trautmann, N.; Türler, A.

    2003-10-01

    Carrier-free short-lived nuclides are employed in many different fields of modern nuclear chemistry. The two main production strategies are either thermal neutron-induced fission of 235U or 239Pu at nuclear reactors or spallation neutron sources or charged particle-induced nuclear reactions at accelerator facilities. An alternative method is to use a spontaneously fissioning nuclide. A facility applying this technique ("Miss Piggy") was built at the University of Berne (Switzerland). Californium-252 ( 252Cf), which has a 3% fission branch and a half-life of 2.645 a, is used for the production of short-lived fission products that are stopped in an adjacent recoil chamber. Short-lived nuclides are transported out of the recoil chamber using the well-known gas-jet technique. Over 100 nuclides have been identified so far and used in different applications. Since such a device does not require any large facility and is easy to operate it serves well the needs of typical university laboratories.

  2. Mitigation of short-lived heating components may lead to unwanted long-term consequences

    NASA Astrophysics Data System (ADS)

    Myhre, Gunnar; Fuglestvedt, Jan S.; Berntsen, Terje K.; Lund, Marianne T.

    2011-10-01

    A mitigation strategy for reducing emissions of short-lived heating components such as black carbon (BC) aerosols and ozone precursors to limit global warming has frequently been suggested ( Bond, 2007; Grieshop et al., 2009; Hansen et al., 2000; Jacobson, 2002; Molina et al., 2009; Nature Editorial, 2009). BC emissions influence the radiative balance in several ways through direct and semi-direct aerosol effects, as well as by impacting the surface albedo ( Forster et al., 2007), and their net effect is likely a warming that enhances the total man-made warming. However, the role that BC or other short-lived heating components may play in future mitigation strategies must be formulated with caution to avoid unforeseen and unwanted consequences. A near-term mitigation of short-lived heating components could lead to a delayed action on CO 2 and other long-lived greenhouse gases and thus an increased long-term warming. A key element is whether policies are designed as a consequence of predicted warming or observed warming. Without a clear strategy, early BC or ozone reductions may even lead to an unexpectedly larger temperature change.

  3. Analyses of new short-lived replacements for HFCs with large GWPs

    NASA Astrophysics Data System (ADS)

    Wuebbles, Donald J.; Wang, Dong; Patten, Kenneth O.; Olsen, Seth C.

    2013-09-01

    this study, we examine the atmospheric lifetimes and Global Warming Potentials (GWPs) for six short-lived potential ozone-depleting substances and high-GWP hydrofluorocarbons (HFCs) replacement compounds and evaluate the potential reduced effects on climate forcing from adopting such compounds. We also examine the potential effects on climate from widespread use of these chemicals. The atmospheric lifetimes of these compounds are each less than 1 month and their 100 year GWPs range from 0.9 to 4.6. The derived GWPs are substantially lower than those in prior published studies, which used simplified estimation techniques that overestimate the GWPs for these short-lived compounds by 61% to 237%. If long-lived HFCs are completely replaced with these substitute compounds, radiative forcing of these short-lived compounds in 2050 will be 0.26 to 0.80 mW m-2, a factor of as much as 1000 smaller than would be the case with the potential growth in the use of the HFCs.

  4. Short-lived K2S Molecules in Superionic Potassium Sulfide

    NASA Astrophysics Data System (ADS)

    Okeya, Yusuke; Tsumuraya, Kazuo

    2015-03-01

    The first principles molecular dynamics method allows us to elucidate the formation of short-lived K2S molecular states in superionic potassium sulfide. The covalent and the Coulomb bonds exist between the ionized mobile potassiums and the ionized immobile sulfurs. Both the bonds induces indirect covalent and indirect Coulomb attractions between the di-interstitial potassiums on the mid-sulfurs, which forms the short-lived K2S molecular states. The covalent electron density also exists between short-lived potassium dimers. The three attractions reduce Haven's ratios of the potassiums in the conductor. The molecule formation indicates the electronic state of the conductor is intermediate between the ionic and covalent crystals. The absence of the long-lived potassium dimers implies a failure of the caterpillar diffusion model or the Frenkel-Kontorova chain model for the superionic diffusion of the potassiums in the sulfide. The incompletely ionized cations and anions reduce the Coulomb attractions between them which induces the sublattice melting of smaller size of the potassiums than the sulfurs.

  5. Classification of short-lived objects using an interactive adaptable assistance system

    NASA Astrophysics Data System (ADS)

    El Bekri, Nadia; Angele, Susanne; Peinsipp-Byma, Elisabeth

    2015-05-01

    "Although we know that it is not a familiar object, after a while we can say what it resembles". The core task of an aerial image analyst is to recognize different object types based on certain clearly classified characteristics from aerial or satellite images. An interactive recognition assistance system compares selected features with a fixed set of reference objects (core data set). Therefore it is mainly designed to evaluate durable single objects like a specific type of ship or vehicle. Aerial image analysts on missions realized a changed warfare over the time. The task was not anymore to classify and thereby recognize a single durable object. The problem was that they had to classify strong variable objects and the reference set did not match anymore. In order to approach this new scope we introduce a concept to a further development of the interactive assistance system to be able to handle also short-lived, not clearly classifiable and strong variable objects like for example dhows. Dhows are the type of ships that are often used during pirate attacks at the coast of West Africa. Often these ships were build or extended by the pirates themselves. They follow no particular pattern as the standard construction of a merchant ship. In this work we differ between short-lived and durable objects. The interactive adaptable assistance system is supposed to assist image analysts with the classification of objects, which are new and not listed in the reference set of objects yet. The human interaction and perception is an important factor in order to realize this task and achieve the goal of recognition. Therefore we had to model the possibility to classify short-lived objects with appropriate procedures taking into consideration all aspects of short-lived objects. In this paper we will outline suitable measures and the possibilities to categorize short-lived objects via simple basic shapes as well as a temporary data storage concept for shortlived objects. The interactive adaptable approach offers the possibility to insert the data (objects) into the system directly and on-site. To mitigate the manipulation risk the entry of data (objects) into the main reference (core data) set is granted to a central authorized unit.

  6. XRF-analysis of fine and ultrafine particles emitted from laser printing devices.

    PubMed

    Barthel, Mathias; Pedan, Vasilisa; Hahn, Oliver; Rothhardt, Monika; Bresch, Harald; Jann, Oliver; Seeger, Stefan

    2011-09-15

    In this work, the elemental composition of fine and ultrafine particles emitted by ten different laser printing devices (LPD) is examined. The particle number concentration time series was measured as well as the particle size distributions. In parallel, emitted particles were size-selectively sampled with a cascade impactor and subsequently analyzed by the means of XRF. In order to identify potential sources for the aerosol's elemental composition, materials involved in the printing process such as toner, paper, and structural components of the printer were also analyzed. While the majority of particle emissions from laser printers are known to consist of recondensated semi volatile organic compounds, elemental analysis identifies Si, S, Cl, Ca, Ti, Cr, and Fe as well as traces of Ni and Zn in different size fractions of the aerosols. These elements can mainly be assigned to contributions from toner and paper. The detection of elements that are likely to be present in inorganic compounds is in good agreement with the measurement of nonvolatile particles. Quantitative measurements of solid particles at 400 °C resulted in residues of 1.6 × 10(9) and 1.5 × 10(10) particles per print job, representing fractions of 0.2% and 1.9% of the total number of emitted particles at room temperature. In combination with the XRF results it is concluded that solid inorganic particles contribute to LPD emissions in measurable quantities. Furthermore, for the first time Br was detected in significant concentrations in the aerosol emitted from two LPD. The analysis of several possible sources identified the plastic housings of the fuser units as main sources due to substantial Br concentrations related to brominated flame retardants. PMID:21809840

  7. High concentrations of coarse particles emitted from a cattle feeding operation

    NASA Astrophysics Data System (ADS)

    Hiranuma, N.; Brooks, S. D.; Gramann, J.; Auvermann, B. W.

    2011-08-01

    Housing roughly 10 million head of cattle in the United States alone, open air cattle feedlots represent a significant but poorly constrained source of atmospheric particles. Here we present a comprehensive characterization of physical and chemical properties of particles emitted from a large representative cattle feedlot in the Southwest United States. In the summer of 2008, measurements and samplings were conducted at the upwind and downwind edges of the facility. A series of far-field measurements and samplings was also conducted 3.5 km north of the facility. Two instruments, a GRIMM Sequential Mobility Particle Sizer (SMPS) and a GRIMM Portable Aerosol Spectrometer (PAS), were used to measure particle size distributions over the range of 0.01 to 25 μm diameter. Raman microspectroscopy was used to determine the chemical composition of particles on a single particle basis. Volume size distributions of dust were dominated by coarse mode particles. Twenty-four hour averaged concentrations of PM10 (particulate matter with a diameter of 10 μm or less) were as high as 1200 μg m-3 during the campaign. The primary constituents of the particulate matter were carbonaceous materials, such as humic acid, water soluble organics, and less soluble fatty acids, including stearic acid and tristearin. A significant fraction of the organic particles was present in internal mixtures with salts. Basic characteristics such as size distribution and composition of agricultural aerosols were found to be different than the properties of those found in urban and semi-urban aerosols. Failing to account for such differences may lead to errors in estimates of aerosol effects on local air quality, visibility, and public health.

  8. ``Sleeping reactor`` irradiations: Shutdown reactor determination of short-lived activation products

    SciTech Connect

    Jerde, E.A.; Glasgow, D.C.

    1998-09-01

    At the High-Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory, the principal irradiation system has a thermal neutron flux ({phi}) of {approximately} 4 {times} 10{sup 14} n/cm{sup 2} {center_dot} s, permitting the detection of elements via irradiation of 60 s or less. Irradiations of 6 or 7 s are acceptable for detection of elements with half-lives of as little as 30 min. However, important elements such as Al, Mg, Ti, and V have half-lives of only a few minutes. At HFIR, these can be determined with irradiation times of {approximately} 6 s, but the requirement of immediate counting leads to increased exposure to the high activity produced by irradiation in the high flux. In addition, pneumatic system timing uncertainties (about {+-} 0.5 s) make irradiations of < 6 s less reliable. Therefore, the determination of these ultra-short-lived species in mixed matrices has not generally been made at HFIR. The authors have found that very short lived activation products can be produced easily during the period after reactor shutdown (SCRAM), but prior to the removal of spent fuel elements. During this 24- to 36-h period (dubbed the ``sleeping reactor``), neutrons are produced in the beryllium reflector by the reaction {sup 9}Be({gamma},n){sup 8}Be, the gamma rays principally originating in the spent fuel. Upon reactor SCRAM, the flux drops to {approximately} 1 {times} 10{sup 10} n/cm{sup 2} {center_dot} s within 1 h. By the time the fuel elements are removed, the flux has dropped to {approximately} 6 {times} 10{sup 8}. Such fluxes are ideal for the determination of short-lived elements such as Al, Ti, Mg, and V. An important feature of the sleeping reactor is a flux that is not constant.

  9. Absence of replicative senescence in cultured cells from the short-lived killifish Nothobranchius furzeri.

    PubMed

    Graf, Michael; Hartmann, Nils; Reichwald, Kathrin; Englert, Christoph

    2013-01-01

    A major challenge in age research is the absence of short-lived vertebrate model organisms. The turquoise killifish Nothobranchius furzeri has the shortest known lifespan of a vertebrate that can be bred in captivity. The short lived GRZ strain only reaches a maximum age of 3-4 months, whereas other strains (MZM) reach 6-10 months. Most importantly, the short lifespan is associated with typical signs of ageing. To find out more about possible cellular factors that might contribute to the short lifespan and to the difference in lifespan between strains, we analyzed the expression of markers for cellular senescence. Expression of Tp53, Cdkn1a and Cdkn2a/b in skin revealed no change in the short-lived GRZ but increased expression of the cell cycle inhibitors Cdkn1a and Cdkn2a/b in the long-lived MZM strain with age. This suggests that expression of distinct cell cycle inhibitors reflects rather chronological than biological age in N. furzeri. To study the relationship of organismal life span and in vitro life span of cells, we established a primary cell culture model. For both strains we demonstrate here the absence of replicative senescence as analysed by morphology, expression of Cdkn1a and Cdkn2a/b, population doubling times and γH2AFX in long-term and short-term cultured cells. We reason this to be on account of sustained telomerase activity and maintained telomeric length. Hence, we propose that differences in maximum life span of different N. furzeri strains is not reflected by differences in proliferation speed or replicative potential of the respective cultured cells. PMID:22445733

  10. Health co-benefits of mitigating short-lived climate forcers

    NASA Astrophysics Data System (ADS)

    Anenberg, S.

    2011-12-01

    Tropospheric ozone and black carbon (BC), a component of fine particulate matter (PM2.5), are associated with premature mortality and disrupt global and regional climate. While attention to their impacts on climate is relatively new, these pollutants have been regulated under health-based standards in the US and elsewhere in the world for decades. Understanding the health benefits of reducing short-lived climate forcers may help inform mitigation strategies, since health will likely continue to drive concern over air quality in the future. Several recent studies have examined the health and climate co-benefits of control measures targeting BC and methane, an ozone precursor. This talk will highlight the health benefits of 14 presently available BC and methane mitigation measures examined in the United Nations Environment Programme/World Meteorological Organization Integrated Assessment of Black Carbon and Ozone. Fully implementing these specific measures is estimated to avoid 1-5 million annual ozone and PM2.5-related premature deaths globally in 2030, >80% of which occur in Asia. BC mitigation measures are estimated to achieve ~98% of the avoided deaths from all measures, due to associated reductions of non-methane ozone precursor and organic carbon emissions and stronger mortality relationships for PM2.5 relative to ozone. These substantial public health co-benefits of mitigating short-lived climate forcers are independent of whether CO2 measures are enacted. Further analyses are needed to improve economic valuation of the varied impacts of short-lived climate forcers and quantify the benefits and costs of these measures in individual countries or regions to support policy decisions made at the national level.

  11. Have we underestimated the role of short-lived chlorine compounds in ozone depletion?

    NASA Astrophysics Data System (ADS)

    Oram, David; Laube, Johannes; Sturges, Bill; Gooch, Lauren; Leedham, Emma; Ashfold, Matthew; Pyle, John; Abu Samah, Azizan; Moi Phang, Siew; Ou-Yang, Chang-Feng; Lin, Neng-Huei; Wang, Jia-Lin; Brenninkmeijer, Carl

    2015-04-01

    In recent years much attention has been focussed on the potential of bromine-containing VSLS (very short lived substances) to contribute to stratospheric ozone depletion. This is primarily due to the large observed discrepancy between the measured inorganic bromine in the stratosphere and the amount of bromine available from known, longer lived sources gases (halons and CH3Br). In contrast, the role of very short-lived chlorine compounds (VSLS-CL) has been considered trivial because they contribute only a few percent to the total organic chlorine in the troposphere, the majority of which is supplied by long-lived compounds such as the CFCs, HCFCs, methyl chloroform and carbon tetrachloride. However recent evidence shows that one VSLS-Cl, dichloromethane (CH2Cl2) has increased by 60% over the past decade (WMO, 2014) and has already begun to offset the long-term decline in stratospheric chlorine loading caused by the reduction in emissions of substances controlled by the Montreal Protocol. We will present new VSLS-Cl measurements from recent ground-based and aircraft campaigns in SE Asia where we have observed dramatic enhancements in a number of VSLS-Cl, including CH2Cl2. Furthermore we will demonstrate how pollution from China and the surrounding region can rapidly, and regularly, be transported across the South China Sea and subsequently uplifted to altitudes of 11-12 km, the region close to the lower TTL. This process occurs frequently during the winter monsoon season and could represent a fast and efficient mechanism for transporting short-lived compounds, and other pollutants, to the lower stratosphere.

  12. Quantum non-locality in a two-slit interferometer for short-lived particles

    SciTech Connect

    Klein, Spencer R.; Nystrand, Joakim

    2001-12-01

    We describe a new test of quantum nonlocality, using an interferometer for short-lived particles. The separation is large compared with the particle lifetimes. This interferometer is realized by vector meson production in distant heavy ion collisions. The mesons decay before waves from the two sources (ions) can overlap, so interference is only possible among the decay products. The post-decay wave function must retain amplitudes for all possible decays. The decay products are spatially separated, necessitating a non-local wave function. The interference is measurable by summing the product momenta. Alternately, the products positions could be observed, allowing new tests of the EPR paradox.

  13. Short-lived positron emitters in beam-on PET imaging during proton therapy

    NASA Astrophysics Data System (ADS)

    Dendooven, P.; Buitenhuis, H. J. T.; Diblen, F.; Heeres, P. N.; Biegun, A. K.; Fiedler, F.; van Goethem, M.-J.; van der Graaf, E. R.; Brandenburg, S.

    2015-12-01

    The only method for in vivo dose delivery verification in proton beam radiotherapy in clinical use today is positron emission tomography (PET) of the positron emitters produced in the patient during irradiation. PET imaging while the beam is on (so called beam-on PET) is an attractive option, providing the largest number of counts, the least biological washout and the fastest feedback. In this implementation, all nuclides, independent of their half-life, will contribute. As a first step towards assessing the relevance of short-lived nuclides (half-life shorter than that of 10C, T1/2  =  19 s) for in vivo dose delivery verification using beam-on PET, we measured their production in the stopping of 55 MeV protons in water, carbon, phosphorus and calcium The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: 12N (T1/2  =  11 ms) on carbon (9% of 11C), 29P (T1/2  =  4.1 s) on phosphorus (20% of 30P) and 38mK (T1/2  =  0.92 s) on calcium (113% of 38gK). No short-lived nuclides are produced on oxygen. The number of decays integrated from the start of an irradiation as a function of time during the irradiation of PMMA and 4 tissue materials has been determined. For (carbon-rich) adipose tissue, 12N dominates up to 70 s. On bone tissue, 12N dominates over 15O during the first 8-15 s (depending on carbon-to-oxygen ratio). The short-lived nuclides created on phosphorus and calcium provide 2.5 times more beam-on PET counts than the long-lived ones produced on these elements during a 70 s irradiation. From the estimated number of 12N PET counts, we conclude that, for any tissue, 12N PET imaging potentially provides equal to superior proton range information compared to prompt gamma imaging with an optimized knife-edge slit camera. The practical implementation of 12N PET imaging is discussed.

  14. Inducible transgenic expression in the short-lived fish Nothobranchius furzeri.

    PubMed

    Allard, J B; Kamei, H; Duan, C

    2013-05-01

    This study demonstrates inducible transgenic expression in the exceptionally short-lived turquoise killifish Nothobranchius furzeri, which is a useful vertebrate model for ageing research. Transgenic N. furzeri bearing a green fluorescent protein (Gfp) containing construct under the control of a heat shock protein 70 promoter were generated, heat shock-induced and reversible Gfp expression was demonstrated and germline transmission of the transgene to the F1 and F2 generations was achieved. The availability of this inducible transgenic expression system will make the study of ageing-related antagonistically pleiotropic genes possible using this unique vertebrate model organism. PMID:23639168

  15. Mass Measurement of Short-lived Nuclei at HIRFL-CSR

    NASA Astrophysics Data System (ADS)

    Wang, M.; Xu, H. S.; Zhang, Y. H.; Tu, X. L.; Litvinov, Yu. A.

    2014-03-01

    Four campaigns of mass measurements for short-lived nuclei have been conducted using an isochronous mass spectrometry (IMS) technique at HIRFL-CSR(Cooler Storage Ring) in Lanzhou. The radioactive nuclei were produced by projectile fragmentation and injected into the experimental storage ring CSRe. Revolution times of the ions stored in the CSRe were measured from which masses of 78Kr, 58Ni, 86Kr and 112Sn fragments have been determined with a relative uncertainty of about 10-6-10-7. The experimental results are presented and their impacts on nucleosynthesis in the rp process and nuclear structure are discussed.

  16. An effective technique for the storage of short lived radioactive gaseous waste.

    PubMed

    Schweiger, Lutz

    2011-09-01

    An effective technique is described to deal with volatile, short lived radioactive waste generated as a result of the routinely produced positron emission tomography (PET) radiopharmaceutical 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG). All radioactive gases and aerosols created during the synthesis are collected and stored safely in commercially available TEDLAR gas sampling bags. Once these collected PET by-products decay, the TEDLAR gas bags can be easily emptied and reused. This improved technique is effective, safe, reliable and economical. PMID:21592805

  17. Properties of short-living ball lightning produced in the laboratory

    NASA Astrophysics Data System (ADS)

    Egorov, A. I.; Stepanov, S. I.

    2008-06-01

    An experimental setup for highly reproducible generation of artificial ball lightnings is implemented. Thousands of floating glowing plasmoids 12-20 cm in diameter are produced. Research facilities for studying the plasmoids are developed. It is found that short-lived ball lightnings live for about 1 s and carry an electric charge. The lightnings are shown to have a complex structure: a central kernel containing a rich variety of hydrated ions and aerosol of decay products is surrounded by a thin negatively charged shell.

  18. Neutron Stars as a Source of the Short-Lived Nuclides in Ap-star Atmospheres

    SciTech Connect

    Gopka, Vera F.; Andrievsky, Sergey M.; Ulyanov, Oleg M.

    2008-05-21

    We propose a new explanation of some magnetic chemically peculiar (MCP) star anomalies, which is based on an assumption that such stars be the close binary systems with a secondary component being a neutron star. Within this hypothesis one can naturally explain the main anomalous features of MCP stars: first of all, an existence of the short-lived radioactive isotopes detected in some stars (like Przybylski's star (PS) and HR465), and some others peculiarities. Also we can assume the presence of the electron-positron annihilation emission lines (0.511 MeV) in the gamma spectrum of some MCP stars.

  19. Short-lived positron emitters in beam-on PET imaging during proton therapy.

    PubMed

    Dendooven, P; Buitenhuis, H J T; Diblen, F; Heeres, P N; Biegun, A K; Fiedler, F; van Goethem, M-J; van der Graaf, E R; Brandenburg, S

    2015-12-01

    The only method for in vivo dose delivery verification in proton beam radiotherapy in clinical use today is positron emission tomography (PET) of the positron emitters produced in the patient during irradiation. PET imaging while the beam is on (so called beam-on PET) is an attractive option, providing the largest number of counts, the least biological washout and the fastest feedback. In this implementation, all nuclides, independent of their half-life, will contribute. As a first step towards assessing the relevance of short-lived nuclides (half-life shorter than that of (10)C, T1/2  =  19 s) for in vivo dose delivery verification using beam-on PET, we measured their production in the stopping of 55 MeV protons in water, carbon, phosphorus and calcium The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: (12)N (T1/2  =  11 ms) on carbon (9% of (11)C), (29)P (T1/2  =  4.1 s) on phosphorus (20% of (30)P) and (38m)K (T1/2  =  0.92 s) on calcium (113% of (38g)K). No short-lived nuclides are produced on oxygen. The number of decays integrated from the start of an irradiation as a function of time during the irradiation of PMMA and 4 tissue materials has been determined. For (carbon-rich) adipose tissue, (12)N dominates up to 70 s. On bone tissue, (12)N dominates over (15)O during the first 8-15 s (depending on carbon-to-oxygen ratio). The short-lived nuclides created on phosphorus and calcium provide 2.5 times more beam-on PET counts than the long-lived ones produced on these elements during a 70 s irradiation. From the estimated number of (12)N PET counts, we conclude that, for any tissue, (12)N PET imaging potentially provides equal to superior proton range information compared to prompt gamma imaging with an optimized knife-edge slit camera. The practical implementation of (12)N PET imaging is discussed. PMID:26539812

  20. Observation in a discharge of short-lived atomic states by intracavity absorption

    SciTech Connect

    Brink, G.O.; Heider, S.M.

    1981-08-01

    Optical absorption in short-lived excited states of atomic neon caused by dye-laser intracavity absorption has been observed. The states were excited by a microwave discharge in neon gas produced by a microwave cavity located inside the optical cavity of the dye laser. All transitions arising from the 2p manifold of states that are usually seen in emission are here seen in absorption. Best theoretical estimates of the number density of each of the 2p states in the discharge is about 10/sup 5/--10/sup 7//cm/sup 3/, and the mean lifetime of the states is about 19 x 10/sup -9/ sec.

  1. Short-lived pollutants in the Arctic: their climate impact and possible mitigation strategies

    SciTech Connect

    Menon, Surabi; Quinn, P.K.; Bates, T.S.; Baum, E.; Doubleday, N.; Fiore, A.M.; Flanner, M.; Fridlind, A.; Garrett, T.J.; Koch, D.; Menon, S.; Shindell, D.; Stohl, A.; Warren, S.G.

    2007-09-24

    Several short-lived pollutants known to impact Arctic climate may be contributing to the accelerated rates of warming observed in this region relative to the global annually averaged temperature increase. Here, we present a summary of the short-lived pollutants that impact Arctic climate including methane, tropospheric ozone, and tropospheric aerosols. For each pollutant, we provide a description of the major sources and the mechanism of forcing. We also provide the first seasonally averaged forcing and corresponding temperature response estimates focused specifically on the Arctic. The calculations indicate that the forcings due to black carbon, methane, and tropospheric ozone lead to a positive surface temperature response indicating the need to reduce emissions of these species within and outside the Arctic. Additional aerosol species may also lead to surface warming if the aerosol is coincident with thin, low lying clouds. We suggest strategies for reducing the warming based on current knowledge and discuss directions for future research to address the large remaining uncertainties.

  2. Short-Lived K2S Molecules in Superionic Potassium Sulfide

    NASA Astrophysics Data System (ADS)

    Tsumuraya, Kazuo; Okeya, Yusuke

    2015-06-01

    First principles molecular dynamics study enables us to elucidate the formation of short-lived K2S molecules in superionic potassium sulfide. Covalent electron densities exist between the ionized immobile sulfurs and their coordinated ionized mobile potassiums forming the respective covalent and the Coulomb bonds between them. Both the bonds induce indirect covalent and indirect Coulomb attractions between the di-interstitial potassiums on the mid-sulfurs forming the molecules. The lifetime of the molecules is 120 fs at 1050 K. The covalent density also exists in short-lived potassium pairs with the lifetime of 110 fs. The three attractions constrain the self-diffusion of the potassiums in the sulfide which reduces Haven's ratios of the potassiums. The absence of the rigid potassium dimers indicates a failure of the chain models for the superionic diffusion. The attractions reduce the Coulomb attractions between them comparing with their completely ionized states which induces the melting of the sublattice of smaller size of the potassiums than the sulfurs: the electronic state of the conductor is intermediate between the ionic crystals and the covalent crystals. The present study classifies the conductors into four types from their electronic states; ionomolecular, ionocovalent, ionometalloid, and ionometallic type superionic conductors.

  3. Activities Study of Short-lived Radioisotopes with a Filippov-type Plasma Focus

    NASA Astrophysics Data System (ADS)

    Zaeem, Alireza Asle; Mahmood Sadat Kiai, S.; Sedaghatizade, Mahmood; Adlparvar, Shirin; Sheibani, Shahab

    2009-09-01

    Plasma focus devices are characterized by short-lived dense and hot plasma "pinch" due to the radial compression and electromagnetic acceleration. Through a short period of time, typically a few tens of nanoseconds, the pinched plasma goes through two phases of compression (thermal) and expansion (non-thermal or beam target) that provide necessary conditions for high nuclear reaction rates. If appropriate gas admixture at a desirable pressure is used, the processes can generate short-lived radioisotopes (SLRs) which the level of activities depends on the design and operational parameters. In this paper, the results of simulated theoretical works of two SLRs such as 10B (d, n) 11C and 14N (d, n) 15O are presented using a Filippov-type plasma focus "Dena" as a breeder with the bank energy ranges from 20 to 90 kJ at the repetition rates from 1 to 10 Hz. The admixture gas pressure of 10B and 14 N were taken to be approximately 0.05 of initial working pressure at optimum neutron yield regime. The results obtained are discussed.

  4. Detection of 210Po on filter papers 16 years after use for the collection of short-lived radon progeny in a room.

    PubMed

    Abu-Jarad, F; Fazal-ur-Rehman

    2003-01-01

    Radon gas was allowed to accumulate in its radium source and then injected into a 36 m(3) test room, resulting in an initial radon concentration of 15 kBq m(-3). Filter papers were used to collect the short-lived radon progeny and thus to measure the Potential Alpha Energy Concentration (PAEC) in-situ in the year 1984 at different times and conditions according to the experimental design. The radon progeny collected on the filter papers were studied as a function of aerosol particle concentration ranging from 10(2)-10(5) particles cm(-3) in three different experiments. The highest aerosol particle concentration was generated by indoor cigarette smoking. Those filters were stored after the experiment, and were used after 16 years to study the activity of the radon long-lived alpha emitter progeny, (210)Po (T(1/2)=138 days). This isotope is separated from the short-lived progeny by (210)Pb beta emitter with 22.3 years half-life. After 16 years' storage of these filters, each filter paper was sandwiched and wrapped between two CR-39 nuclear track detectors, to put the detectors in contact with the surfaces of different filters, for 337 days. Correlation between the PAEC measured using filter papers in the year 1984 and the activity of long-lived alpha emitter (210)Po on the same filter papers measured in the year 2000 were studied. The results of the (210)Po activity showed a very good correlation of 0.92 with the PAEC 16 years ago. The results also depict that the PAEC and (210)Po activity in indoor air increased with the increase of aerosol particle concentration, which shows the attachment of short-lived radon progeny with the aerosol particles. The experiment proves that indoor cigarette smoking is a major source of aerosol particles carrying radon progeny and, thus, indoor cigarette smoking is an additional source of internal radiation hazard to the occupants whether smoker or non-smoker. PMID:12633999

  5. Elements and polycyclic aromatic hydrocarbons in exhaust particles emitted by light-duty vehicles.

    PubMed

    Alves, Célia A; Barbosa, Cátia; Rocha, Sónia; Calvo, Ana; Nunes, Teresa; Cerqueira, Mário; Pio, Casimiro; Karanasiou, Angeliki; Querol, Xavier

    2015-08-01

    The main purpose of this work was to evaluate the chemical composition of particulate matter (PM) emitted by eight different light-duty vehicles. Exhaust samples from petrol and diesel cars (Euro 3 to Euro 5) were collected in a chassis dynamometer facility. To simulate the real-world driving conditions, three ARTEMIS cycles were followed: road, to simulate a fluid traffic flow and urban with hot and cold starts, to simulate driving conditions in cities. Samples were analysed for the water-soluble ions, for the elemental composition and for polycyclic aromatic hydrocarbons (PAHs), respectively, by ion chromatography, inductively coupled plasma atomic emission spectroscopy (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS) and gas chromatography-mass spectrometry (GC-MS). Nitrate and phosphate were the major water-soluble ions in the exhaust particles emitted from diesel and petrol vehicles, respectively. The amount of material emitted is affected by the vehicle age. For vehicles ≥Euro 4, most elements were below the detection limits. Sodium, with emission factors in the ranges 23.5-62.4 and 78.2-227μg km(-1), for petrol and diesel Euro 3 vehicles, respectively, was the major element. The emission factors of metallic elements indicated that diesel vehicles release three to five times more than petrol automobiles. Element emissions under urban cycles are higher than those found for on-road driving, being three or four times higher, for petrol vehicles, and two or three times, for diesel vehicles. The difference between cycles is mainly due to the high emissions for the urban cycle with hot start-up. As registered for elements, most of the PAH emissions for vehicles ≥Euro 4 were also below the detection limits. Regardless of the vehicle models or driving cycles, the two- to four-ring PAHs were always dominant. Naphthalene, with emission factors up to 925 μg km(-1), was always the most abundant PAH. The relative cancer risk associated with naphthalene was estimated to be up to several orders of magnitude higher than any of the chemical species found in the PM phase. The highest PAH emission factors were registered for diesel-powered vehicles. The condition of the vehicle can exert a decisive influence on both element and PAH emissions. PMID:25827652

  6. Detection and localization of particle-emitting sources with compound-eye inspired detector arrays

    NASA Astrophysics Data System (ADS)

    Liu, Zhi

    2007-08-01

    We develop methods to detect and localize particle-emitting sources using detector arrays that are inspired by biological compound eyes. The sources of interest may be optical, nuclear, or cosmic; they emit particles such as visible photons, neutrons, protons, or charged particles. Our results may have wide applications to artificial vision, which can be important in robotics (robot vision) or medicine (e.g., artificial eyes for the blind); security, where the detection of nuclear materials is needed; or astronomy. This dissertation consists of three parts. First, we detect a far-field particle source using two directional detector arrays: cubic and spherical. We propose a mean-difference test (MDT) detector, analyze its statistical performance, and show that the MDT has a number of advantages over the generalized likelihood- ratio test (GLRT). Second, we localize the source by proposing a novel biologically inspired detector array, whose configuration generalizes the compound eye of insects. This array combines the advantages of compound eyes (e.g., large field-of-view) and human eyes (e.g., high angular resolution). Based on a statistical model of the array measurements, we analyze the array performance by computing the Cramérao bound (CRB) on the error in estimating the source direction. We also derive lower bounds on the mean-square angular error (MSAE) of the source localization and investigate the MSAE of two source- direction estimators. Numerical examples, including the optimal array design, are presented to further illustrate the array performance. Third, we derive a statistical angular resolution limit (ARL) on resolving two closely spaced point sources in a three-dimensional frame, which is applicable to various measurement models (e.g., radar, sonar, or astronomy). Using the asymptotic analysis of the GLRT, we derive the ARL with constraints on the probabilities of false alarm and detection. Our results give explicit analytical expression for the ARL that is proportional to the square root of the CRB on the angular source separation, or equivalently to the lower bound on the MSAE.

  7. The Apollo Alpha Spectrometer.

    NASA Technical Reports Server (NTRS)

    Jagoda, N.; Kubierschky, K.; Frank, R.; Carroll, J.

    1973-01-01

    Located in the Science Instrument Module of Apollo 15 and 16, the Alpha Particle Spectrometer was designed to detect and measure the energy of alpha particles emitted by the radon isotopes and their daughter products. The spectrometer sensor consisted of an array of totally depleted silicon surface barrier detectors. Biased amplifier and linear gate techniques were utilized to reduce resolution degradation, thereby permitting the use of a single 512 channel PHA. Sensor identification and in-flight radioactive calibration were incorporated to enhance data reduction.

  8. A multi-proxy approach to identifying short-lived marine incursions in the Early Carboniferous

    NASA Astrophysics Data System (ADS)

    Bennett, Carys; Davies, Sarah; Leng, Melanie; Snelling, Andrea; Millward, David; Kearsey, Timothy; Marshall, John; Reves, Emma

    2015-04-01

    This study is a contribution to the TW:eed Project (Tetrapod World: early evolution and diversification), which examines the rebuilding of Carboniferous ecosystems following a mass extinction at the end of the Devonian. The project focuses on the Tournaisian Ballagan Formation of Scotland and the Borders, which contains rare fish and tetrapod material. The Ballagan Formation is characterised by sandstones, dolomitic cementstones, paleosols, siltstones and gypsum deposits. The depositional environment ranges from fluvial, alluvial-plain to marginal-marine environments, with fluvial, floodplain and lacustrine deposition dominant. A multi-proxy approach combining sedimentology, palaeontology, micropalaeontology, palynology and geochemistry is used to identify short-lived marine transgressions onto the floodplain environment. Rare marginal marine fossils are: Chondrites-Phycosiphon, Spirorbis, Serpula, certain ostracod species, rare orthocones, brachiopods and putative marine sharks. More common non-marine fauna include Leiocopida and Podocopida ostracods, Mytilida and Myalinida bivalves, plants, eurypterids, gastropods and fish. Thin carbonate-bearing dolomitic cementstones and siltstone contain are the sedimentary deposits of marine incursions and occur throughout the formation. Over 600 bulk carbon isotope samples were taken from the 500 metre thick Norham Core (located near Berwick-Upon-Tweed), encompassing a time interval of around 13 million years. The results range from -26o to -19 δ13Corg, with an average of -19o much lighter than the average value for Early Carboniferous marine bulk organic matter (δ13C of -28 to -30). The isotope results correspond to broad-scale changes in the depositional setting, with more positive δ13C in pedogenic sediments and more negative δ13C in un-altered grey siltstones. They may also relate to cryptic (short-lived) marine incursions. A comparison of δ13C values from specific plant/wood fragments, palynology and bulk sedimentary organic matter from the core is used to identify further changes in environment and vegetation. From the base to the top of the formation, there is a gradual increase in relatively drier conditions, with more developed palaeosols and deep desiccation cracks. However, the main character of the formation is that of rapidly changing deposition between silts, sands and carbonates with many periods of pedogenesis and/or desiccation suggesting frequent switching from alluvial-plain to coastal environments. Marine incursions were short-lived, but important and caused a significant increase in the macro and microfaunal diversity. This temporal variability in the environments may have been an important factor in the evolution of tetrapods in the Early Carboniferous.

  9. Implicit short-lived motor representations of space in brain damaged and healthy subjects.

    PubMed

    Rossetti, Y

    1998-09-01

    This article reviews experimental evidence for a specific sensorimotor function which can be dissociated from higher level representations of space. It attempts to delineate this function on the basis of results obtained by psychophysical experiments performed with brain damaged and healthy subjects. Eye and hand movement control exhibit automatic features, such that they are incompatible with conscious control. In addition, they rely on a reference frame different from the one used by conscious perception. Neuropsychological cases provide a strong support for this specific motor representation of space, which can be spared in patients with lesions of primary sensory systems who have lost conscious perception of visual, tactile or proprioceptive stimuli. Observation of these patients also showed that their motor behavior can be "attracted" by a goal only under specific conditions, that is, when the response is immediate and when no cognitive representation of this goal is elaborated at the same time. Beyond the issue of the dissociation between an implicit motor representation and more cognitive processing of spatial information, the issue of the interaction between these two systems is thus a matter of interest. It is suggested that the conscious, cognitive representation of a stimulus can contaminate or override the short-lived motor representation, but no reciprocal influence seem to occur. The interaction observed in patients can also be investigated in normals. The literature provides examples of interaction between sensorimotor and cognitive framing of space, which confirm that immediate action is not mediated by the same system as delayed action, and that elaborating a categorial representation of the action goal prevents the expression of the short-lived sensorimotor representation. It is concluded that action can be controlled by a sensory system which is specialized for on-line processing of relevant goal characteristics. The temporal constraints of this system are such that it can affect the action before a full sensory analysis of this goal has been completed. The performance obtained on the basis of this spatial sensory processing suggests that short-lived motor representations may rather be considered as real "presentation" of the action world, which share its metric properties. PMID:9787059

  10. Inter-laboratory comparisons of short-lived gamma-emitting radionuclides in nuclear reactor water.

    PubMed

    Klemola, S K

    2008-01-01

    Inter-laboratory comparisons of gamma-emitting nuclides in nuclear power plant coolant water have been carried out in Finland since 1994. The reactor water samples are taken and prepared by one of the two nuclear power plants and delivered to the participants. Since all the participants get their sample within just a few hours it has been possible to analyse and compare results of nuclides with half-lives shorter than 1h. The total number of short-lived nuclides is 26. All the main nuclides are regularly identified and the activities have been obtained with reasonable accuracy throughout the years. The overall deviation of the results has decreased in 13 years. The effects of true coincidence summing and discrepancies in nuclear data have been identified as potential sources of remaining discrepancies. All the participants have found this type of comparison very useful. PMID:18378157

  11. Separation efficiency of the MASHA facility for short-lived mercury isotopes

    NASA Astrophysics Data System (ADS)

    Rodin, A. M.; Belozerov, A. V.; Chernysheva, E. V.; Dmitriev, S. N.; Gulyaev, A. V.; Gulyaeva, A. V.; Itkis, M. G.; Kliman, J.; Kondratiev, N. A.; Krupa, L.; Novoselov, A. S.; Oganessian, Yu. Ts.; Podshibyakin, A. V.; Salamatin, V. S.; Siváček, I.; Stepantsov, S. V.; Vanin, D. V.; Vedeneev, V. Yu.; Yukhimchuk, S. A.; Granja, C.; Pospisil, S.

    2014-06-01

    The mass-separator MASHA built to identify Super Heavy Elements by their mass-to-charge ratios is described. The results of the off- and on-line measurements of its separation efficiency are presented. In the former case four calibrated leaks of noble gases were used. In the latter the efficiency was measured via 284 MeV Ar beam and with using the hot catcher. The ECR ion source was used in both cases. The -radioactive isotopes of mercury produced in the complete fusion reaction Ar+SmHg+xn were detected at the mass-separator focal plane. The half-lives and the separation efficiency for the short-lived mercury isotopes were measured. Potentialities of the MEDIPIX detector system have been demonstrated for future use at the mass-separator MASHA.

  12. Counteracting the climate effects of volcanic eruptions using short-lived greenhouse gases

    NASA Astrophysics Data System (ADS)

    Fuglestvedt, Jan S.; Samset, Bjrn H.; Shine, Keith P.

    2014-12-01

    A large volcanic eruption might constitute a climate emergency, significantly altering global temperature and precipitation for several years. Major future eruptions will occur, but their size or timing cannot be predicted. We show, for the first time, that it may be possible to counteract these climate effects through deliberate emissions of short-lived greenhouse gases, dampening the abrupt impact of an eruption. We estimate an emission pathway countering a hypothetical eruption 3 times the size of Mount Pinatubo in 1991. We use a global climate model to evaluate global and regional responses to the eruption, with and without counteremissions. We then raise practical, financial, and ethical questions related to such a strategy. Unlike the more commonly discussed geoengineering to mitigate warming from long-lived greenhouse gases, designed emissions to counter temporary cooling would not have the disadvantage of needing to be sustained over long periods. Nevertheless, implementation would still face significant challenges.

  13. The short-lived African turquoise killifish: an emerging experimental model for ageing.

    PubMed

    Kim, Yumi; Nam, Hong Gil; Valenzano, Dario Riccardo

    2016-02-01

    Human ageing is a fundamental biological process that leads to functional decay, increased risk for various diseases and, ultimately, death. Some of the basic biological mechanisms underlying human ageing are shared with other organisms; thus, animal models have been invaluable in providing key mechanistic and molecular insights into the common bases of biological ageing. In this Review, we briefly summarise the major applications of the most commonly used model organisms adopted in ageing research and highlight their relevance in understanding human ageing. We compare the strengths and limitations of different model organisms and discuss in detail an emerging ageing model, the short-lived African turquoise killifish. We review the recent progress made in using the turquoise killifish to study the biology of ageing and discuss potential future applications of this promising animal model. PMID:26839399

  14. Laser generation of proton beams for the production of short-lived positron emitting radioisotopes

    NASA Astrophysics Data System (ADS)

    Spencer, I.; Ledingham, K. W. D.; Singhal, R. P.; McCanny, T.; McKenna, P.; Clark, E. L.; Krushelnick, K.; Zepf, M.; Beg, F. N.; Tatarakis, M.; Dangor, A. E.; Norreys, P. A.; Clarke, R. J.; Allott, R. M.; Ross, I. N.

    2001-10-01

    Protons of energies up to 37 MeV have been generated when ultra-intense lasers (up to 10 20 W cm -2) interact with hydrogen containing solid targets. These protons can be used to induce nuclear reactions in secondary targets to produce β +-emitting nuclei of relevance to the nuclear medicine community, namely 11C and 13N via (p, n) and (p,α) reactions. Activities of the order of 200 kBq have been measured from a single laser pulse interacting with a thin solid target. The possibility of using ultra-intense lasers to produce commercial amounts of short-lived positron emitting sources for positron emission tomography (PET) is discussed.

  15. Contribution of very short-lived substances to stratospheric bromine loading: uncertainties and constraints

    NASA Astrophysics Data System (ADS)

    Aschmann, J.; Sinnhuber, B.-M.

    2013-02-01

    Very short-lived substances (VSLS) still represent a major factor of uncertainty in the quantification of stratospheric bromine loading. One of the major obstacles for short-lived source gases in contributing to the stratosphere is generally thought to be loss of inorganic bromine (Bry) in the tropical tropopause layer (TTL) due to dehydration. We use sensitivity calculations with a three-dimensional chemistry transport model comprising a consistent parametrization of convective transport and a comprehensive chemistry scheme to investigate the associated processes. The model considers the two most important bromine VSLS, bromoform (CHBr3) and dibromomethane (CH2Br2). The organic bromine source gases as well as the resulting profile of inorganic bromine in the model are consistent with available observations. In contrast to its organic precursors, Bry is assumed to have a significant sorption capacity regarding sedimenting liquid or frozen particles thus the fraction of intact source gases during their ascent through the TTL is a critical factor. We find that source gas injection is the dominant pathway into the stratosphere, about 50% of CHBr3 and 94% of CH2Br2 is able to overcome the cold point tropopause at approximately 17 km altitude, modulated by the interannual variability of the vertical transport efficiency. In fact, our sensitivity calculations indicate that the extent of source gas injection of CHBr3 is highly sensitive to the strength of convection and large-scale ascent; in contrast, modifying the photolysis or the destruction via OH yields a significantly smaller response. In principle, the same applies as well to CH2Br2, though it is considerably less responsive due to its longer lifetime. The next important aspect we identified is that the partitioning of available Bry from short-lived sources is clearly shifted away from HBr, according to our current state of knowledge the only member of the Bry family which is efficiently adsorbed on ice particles. This effect is caused by very efficient heterogeneous reactions on ice surfaces which reduce the HBr/Bry fraction below 15% at the tropical tropopause. Under these circumstances there is no significant loss of Bry due to dehydration in the model, VSLS contribute fully to stratospheric bromine. In addition, we conduct several sensitivity calculations to test the robustness of this result. If heterogeneous chemistry is ignored, the HBr/Bry fraction exceeds 50% and about 10% of bromine from VSLS is scavenged. Dehydration plays a minor role for Bry removal under the assumption that HOBr is efficiently adsorbed on ice as well since the heterogeneous reactions alter the partitioning equilibrium of Bry in favor of HOBr. In this case, up to 12% of bromine from VSLS is removed. Even in the extreme and unrealistic case that adsorbed species on ice particles are instantaneously removed the maximum loss of bromine does not exceed 25%. Assuming 6 parts per trillion by volume (pptv) of bromine short-lived source gases in convective updrafts, a value that is supported by observational data, we find a most likely contribution of VSLS to stratospheric bromine in the range of 4.5-6 pptv.

  16. Contribution of very short-lived substances to stratospheric bromine loading: uncertainties and constraints

    NASA Astrophysics Data System (ADS)

    Aschmann, J.; Sinnhuber, B.-M.

    2012-11-01

    Very short-lived substances (VSLS) still represent a major factor of uncertainty in the quantification of stratospheric bromine loading. One of the major obstacles for short-lived source gases in contributing to the stratosphere is generally thought to be loss of inorganic bromine (Bry) in the tropical tropopause layer (TTL) due to dehydration. We use sensitivity calculations with a~three-dimensional chemistry transport model comprising a consistent parametrization of convective transport and a comprehensive chemistry scheme to investigate the associated processes. The model considers the two most important bromine VSLS, bromoform (CHBr3) and dibromomethane (CH2Br2). The organic bromine source gases as well as the resulting profile of inorganic bromine in the model are consistent with available observations. In contrast to its organic precursors, Bry is assumed to have a~significant sorption capacity regarding sedimenting liquid or frozen particles thus the fraction of intact source gases during their ascent through the TTL is a critical factor. We find that source gas injection is the dominant pathway into the stratosphere, about 50% of CHBr3 and 93% of CH2Br2 is able to overcome the cold point tropopause at approximately 17 km altitude, modulated by the interannual variability of the vertical transport efficiency. In fact, our sensitivity calculations indicate that the extent of source gas injection of CHBr3 is highly sensitive to the strength of convection and large-scale ascent; in contrast, modifying the photolysis or the destruction via OH yields a significantly smaller response. In principal, the same applies as well to CH2Br2, though it is considerably less responsive due to its longer lifetime. The next important aspect we identified is that the partitioning of available Bry from short-lived sources is clearly shifted away from HBr, according to our current state of knowledge the only member of the Bry family which is efficiently adsorbed on ice particles. This effect is caused by very efficient heterogeneous reactions on ice surfaces which reduce the HBr/Bry fraction below 15% at the tropical tropopause. Under these circumstances there is no significant loss of Bry due to dehydration in the model, VSLS contribute fully to stratospheric bromine. In addition, we conduct several sensitivity calculations to test the robustness of this result. If heterogeneous chemistry is ignored, the HBr/Bry fraction exceeds 50% and about 10% of bromine from VSLS is scavenged. Dehydration plays a minor role for Bry removal under the assumption that HOBr is efficiently adsorbed on ice as well since the heterogeneous reactions alter the partitioning equilibrium of Bry in favor of HOBr. In this case, up to 12% of bromine from VSLS is removed. Even in the extreme and unrealistic case that adsorbed species on ice particles are instantaneously removed the maximum loss of bromine does not exceed 25%. In conclusion, considering the average abundance of bromine short-lived source gases in convective updrafts of 6 parts per trillion by volume (pptv) we find a most likely contribution of VSLS to stratospheric bromine in the range of 4.5-6 pptv.

  17. The role of short-lived climate pollutants in meeting temperature goals

    NASA Astrophysics Data System (ADS)

    Bowerman, Niel H. A.; Frame, David J.; Huntingford, Chris; Lowe, Jason A.; Smith, Stephen M.; Allen, Myles R.

    2013-12-01

    Some recent high-profile publications have suggested that immediately reducing emissions of methane, black carbon and other short-lived climate pollutants (SLCPs) may contribute substantially towards the goal of limiting global warming to 2 °C above pre-industrial levels. Although this literature acknowledges that action on long-lived climate pollutants (LLCPs) such as CO2 is also required, it is not always appreciated that SLCP emissions in any given decade only have a significant impact on peak temperature under circumstances in which CO2 emissions are falling. Immediate action on SLCPs might potentially 'buy time' for adaptation by reducing near-term warming; however early SLCP reductions, compared with reductions in a future decade, do not buy time to delay reductions in CO2.

  18. Short-lived oxygen diffusion during hot, deep-seated meteoric alteration of anorthosite

    PubMed

    Mora; Riciputi; Cole

    1999-12-17

    Heterogeneous oxygen isotope compositions of plagioclase from the Boehls Butte anorthosite include some of the most oxygen-18-depleted values (to -16 per mil) reported for plagioclase in meta-igneous rocks and indicate high-temperature (T > 500 degrees C) isotopic exchange between plagioclase and nearly pristine meteoric fluid. Retrograde reaction-enhanced permeability assisted influx of meteoric-hydrothermal fluids into the deep-seated anorthosite. Isotopic gradients of about 14 per mil over 600 micrometers in single crystals require short-lived (about 10(4) years) diffusional exchange of oxygen and locally large effective water:rock ratios, followed by rapid loss of water and cessation of oxygen diffusion in the anorthosite. PMID:10600738

  19. Dynamical Detection of Topological Phase Transitions in Short-Lived Atomic Systems.

    PubMed

    Setiawan, F; Sengupta, K; Spielman, I B; Sau, Jay D

    2015-11-01

    We demonstrate that dynamical probes provide direct means of detecting the topological phase transition (TPT) between conventional and topological phases, which would otherwise be difficult to access because of loss or heating processes. We propose to avoid such heating by rapidly quenching in and out of the short-lived topological phase across the transition that supports gapless excitations. Following the quench, the distribution of excitations in the final conventional phase carries signatures of the TPT. We apply this strategy to study the TPT into a Majorana-carrying topological phase predicted in one-dimensional spin-orbit-coupled Fermi gases with attractive interactions. The resulting spin-resolved momentum distribution, computed by self-consistently solving the time-dependent Bogoliubov-de Gennes equations, exhibits Kibble-Zurek scaling and Stückelberg oscillations characteristic of the TPT. We discuss parameter regimes where the TPT is experimentally accessible. PMID:26588362

  20. Laser spectroscopy of trapped short-lived Ra{sup +} ions

    SciTech Connect

    Versolato, O. O.; Giri, G. S.; Wansbeek, L. W.; Berg, J. E. van den; Hoek, D. J. van der; Jungmann, K.; Kruithof, W. L.; Onderwater, C. J. G.; Sahoo, B. K.; Santra, B.; Shidling, P. D.; Timmermans, R. G. E.; Willmann, L.; Wilschut, H. W.

    2010-07-15

    As an important step toward an atomic parity violation experiment in one single trapped Ra{sup +} ion, laser spectroscopy on short-lived {sup 212,213,214}Ra{sup +} ions was conducted. The isotope shift of the 6 {sup 2}D{sub 3/2}-7 {sup 2}P{sub 1/2} and 6 {sup 2}D{sub 3/2}-7 {sup 2}P{sub 3/2} transitions and the hyperfine structure constants of the 7 {sup 2}P{sub 1/2} and 6 {sup 2}D{sub 3/2} states in {sup 213}Ra{sup +} were measured, which provides a benchmark for the required atomic theory. A lower limit of 232(4) ms for 6 {sup 2}D{sub 5/2} state lifetime was determined.

  1. New Short-Lived Isotope 221U and the Mass Surface Near N =126

    NASA Astrophysics Data System (ADS)

    Khuyagbaatar, J.; Yakushev, A.; Düllmann, Ch. E.; Ackermann, D.; Andersson, L.-L.; Block, M.; Brand, H.; Cox, D. M.; Even, J.; Forsberg, U.; Golubev, P.; Hartmann, W.; Herzberg, R.-D.; Heßberger, F. P.; Hoffmann, J.; Hübner, A.; Jäger, E.; Jeppsson, J.; Kindler, B.; Kratz, J. V.; Krier, J.; Kurz, N.; Lommel, B.; Maiti, M.; Minami, S.; Mistry, A. K.; Mrosek, Ch. M.; Pysmenetska, I.; Rudolph, D.; Sarmiento, L. G.; Schaffner, H.; Schädel, M.; Schausten, B.; Steiner, J.; De Heidenreich, T. Torres; Uusitalo, J.; Wegrzecki, M.; Wiehl, N.; Yakusheva, V.

    2015-12-01

    Two short-lived isotopes 221U and 222U were produced as evaporation residues in the fusion reaction 50Ti + 176Yb at the gas-filled recoil separator TASCA. An α decay with an energy of Eα=9.31 (5 ) MeV and half-life T1 /2=4.7 (7 ) μ s was attributed to 222U. The new isotope 221U was identified in α -decay chains starting with Eα=9.71 (5 ) MeV and T1 /2=0.66 (14 ) μ s leading to known daughters. Synthesis and detection of these unstable heavy nuclei and their descendants were achieved thanks to a fast data readout system. The evolution of the N =126 shell closure and its influence on the stability of uranium isotopes are discussed within the framework of α -decay reduced width.

  2. The short-lived African turquoise killifish: an emerging experimental model for ageing

    PubMed Central

    Kim, Yumi; Nam, Hong Gil; Valenzano, Dario Riccardo

    2016-01-01

    ABSTRACT Human ageing is a fundamental biological process that leads to functional decay, increased risk for various diseases and, ultimately, death. Some of the basic biological mechanisms underlying human ageing are shared with other organisms; thus, animal models have been invaluable in providing key mechanistic and molecular insights into the common bases of biological ageing. In this Review, we briefly summarise the major applications of the most commonly used model organisms adopted in ageing research and highlight their relevance in understanding human ageing. We compare the strengths and limitations of different model organisms and discuss in detail an emerging ageing model, the short-lived African turquoise killifish. We review the recent progress made in using the turquoise killifish to study the biology of ageing and discuss potential future applications of this promising animal model. PMID:26839399

  3. Seeds of alpine plants are short lived: implications for long-term conservation

    PubMed Central

    Mondoni, Andrea; Probert, Robin J.; Rossi, Graziano; Vegini, Emanuele; Hay, Fiona R.

    2011-01-01

    Background and Aims Alpine plants are considered one of the groups of species most sensitive to the direct and indirect threats to ecosystems caused by land use and climate change. Collecting and banking seeds of plant species is recognized as an effective tool for providing propagating material to re-establish wild plant populations and for habitat repair. However, seeds from cold wet environments have been shown to be relatively short lived in storage, and therefore successful long-term seed conservation for alpine plants may be difficult. Here, the life spans of 69 seed lots representing 63 related species from alpine and lowland locations from northern Italy are compared. Methods Seeds were placed into experimental storage at 45 °C and 60 % relative humidity (RH) and regularly sampled for germination. The time taken in storage for viability to fall to 50 % (p50) was determined using probit analysis and used as a measure of relative seed longevity between seed lots. Key Results Across species, p50 at 45 °C and 60 % RH varied from 4·7 to 95·5 d. Seed lots from alpine populations/species had significantly lower p50 values compared with those from lowland populations/species; the lowland seed lots showed a slower rate of loss of germinability, higher initial seed viability, or both. Seeds were progressively longer lived with increased temperature and decreased rainfall at the collecting site. Conclusions Seeds of alpine plants are short lived in storage compared with those from lowland populations/related taxa. The lower resistance to ageing in seeds of alpine plants may arise from low selection pressure for seed resistance to ageing and/or damage incurred during seed development due to the cool wet conditions of the alpine climate. Long-term seed conservation of several alpine species using conventional seed banking methods will be problematic. PMID:21081585

  4. CARIBIC observations of short-lived halocarbons and carbonyl sulphide over Asia

    NASA Astrophysics Data System (ADS)

    Leedham, E.; Wisher, A.; Oram, D.; Baker, A. K.; Brenninkmeijer, C. A.

    2013-12-01

    The CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container, www.caribic-atmospheric.com) aims to investigate the spatial and temporal distribution of a wide-range of compounds, including those of marine origin/influence, via ~monthly flights to collect in situ data and whole air samples aboard a commercial Lufthansa aircraft. CARIBIC measures up to an altitude of 12 km, allowing the influence of marine compounds on the upper troposphere/lower stratosphere (UTLS) to be explored. In particular, CARIBIC is a useful tool for exploring the impact of very short lived halocarbons (e.g. CH2Br2, CHBr3), whose impact on stratospheric ozone is dependent on convective uplift to the UTLS, a process which is not yet fully quantified. As part of the suite of CARIBIC measurements, whole air samples are analysed at the University of East Anglia (UEA) via gas chromatography mass spectrometry for carbonyl sulphide (OCS) and up to 40 halocarbons (accounting for virtually 100% of organic chlorine, bromine and iodine in the UTLS). Here we present an overview of short-lived halocarbons and OCS measured by CARIBIC. We focus on two regions of particular interest. (1) measurements made in 2012 over the tropical west Pacific to link with UEA measurements made during the SHIVA campaign. (2) measurements made during a collection of flights over India in 2008. Flights over India investigated the impact of monsoon circulation on the distribution of these compounds; for example, elevated concentrations of OCS were seen in CARIBIC samples taken over India during the summer monsoon (July - September). These flights, along with a wider range of flights over Asia (from Frankfurt to Guangzhou, Manila, Bangkok and Kuala Lumpur) can provide unique information on the influence of tropical convection and monsoon circulation on halocarbon and OCS transport within this region.

  5. Muscle Senescence in Short-Lived Wild Mammals, the Soricine Shrews Blarina brevicauda and Sorex palustris

    PubMed Central

    HINDLE, ALLYSON G.; LAWLER, JOHN M.; CAMPBELL, KEVIN L.; HORNING, MARKUS

    2015-01-01

    Red-toothed (soricine) shrews are consummate predators exhibiting the highest energy turnovers and shortest life spans (ca. 18 months) of any mammal, yet virtually nothing is known regarding their physiological aging. We assessed the emerging pattern of skeletal muscle senescence (contractile/connective tissue components) in sympatric species, the semi-aquatic water shrew (WS), Sorex palustris, and the terrestrial short-tailed shrew (STS), Blarina brevicauda, to determine if muscle aging occurs in wild, short-lived mammals (H0: shrews do not survive to an age where senescence occurs), and if so, whether these alterations are species-specific. Gracilis muscles were collected from first-year (n = 17) and second-year (n = 17) field-caught shrews. Consistent with typical mammalian aging, collagen content (% area) increased with age in both species (S. palustris: ~50%; B. brevicauda: ~60%). Muscle was dominated by stiffer Type I collagen, and the ratio of collagen Type I:Type III more than doubled with age. The area ratio of muscle:collagen decreased with age in both species, but was considerably lower in adult STS, suggesting species-specificity of senescence. Extracellular space was age-elevated in B. brevicauda, but was preserved in S. palustris (~50 vs. 10% elevation). Though juvenile interspecific comparisons revealed no significance, adult WS myocytes had 68% larger cross-sectional area and occurred at 28% lower fibers/area than those of adult STS. We demonstrate that age-related muscle senescence does occur in wild-caught, short-lived mammals, and we therefore reject this classic aging theory tenet. Our findings moreover illustrate that differential age adjustments in contractile/connective tissue components of muscle occur in the two species of wild-caught shrews. PMID:19296507

  6. Global Air Quality and Climate Impacts of Mitigating Short-lived Climate Pollution in China

    NASA Astrophysics Data System (ADS)

    Harper, K.; Unger, N.; Heyes, C.; Kiesewetter, G.; Klimont, Z.; Schoepp, W.; Wagner, F.

    2014-12-01

    China is a major emitter of harmful air pollutants, including the short-lived climate pollutants (SLCPs) and their precursors. Implementation of pollution control technologies provides a mechanism for simultaneously protecting human and ecosystem health and achieving near-term climate co-benefits; however, predicting the outcomes of technical and policy interventions is challenging because the SLCPs participate in both climate warming and cooling and share many common emission sources. Here, we present the results of a combined regional integrated assessment and global climate modeling study aimed at quantifying the near-term climate and air quality co-benefits of selective control of Chinese air pollution emissions. Results from IIASA's Greenhouse Gas - Air Pollution Interactions and Synergies (GAINS) integrated assessment model indicate that methane emission reductions make up > 75% of possible CO2-equivalent emission reductions of the SLCPs and their precursors in China in 2030. A multi-pollutant emission reduction scenario incorporating the 2030 Chinese pollution control measures with the highest potential for future climate impact is applied to the NASA ModelE2 - Yale Interactive Terrestrial Biosphere (NASA ModelE2-YIBs) global carbon - chemistry - climate model to assess the regional and long-range impacts of Chinese SLCP mitigation measures. Using model simulations that incorporate dynamic methane emissions and photosynthesis-dependent isoprene emissions, we quantify the impacts of Chinese reductions of the short-lived air pollutants on radiative forcing and on surface ozone and particulate air pollution. Present-day modeled methane mole fractions are evaluated against SCIAMACHY methane columns and NOAA ESRL/GMD surface flask measurements.

  7. Power-density spectrum of non-stationary short-lived light curves

    NASA Astrophysics Data System (ADS)

    Guidorzi, Cristiano

    2011-08-01

    The power-density spectrum of a light curve is often calculated as the average of a number of spectra derived on individual time intervals the light curve is divided into. This procedure implicitly assumes that each time interval is a different sample function of the same stochastic ergodic process. While this assumption can be applied to many astrophysical sources, there remains a class of transient, highly non-stationary and short-lived events, such as gamma-ray bursts, for which this approach is often inadequate. The power spectrum statistics of a constant signal affected by statistical (Poisson) noise are known to be a χ22 in the Leahy normalization. However, this is no more the case when a non-stationary signal is also present. As a consequence, the uncertainties on the power spectrum cannot be calculated on the basis of the χ22 properties, as assumed by tools such as XRONOS POWSPEC. We generalize the result in the case of a non-stationary signal affected by uncorrelated white noise and show that the new distribution is a non-central χ22(λ), whose non-central value λ is the power spectrum of the deterministic function describing the non-stationary signal. Finally, we test these results in the case of synthetic curves of gamma-ray bursts. We end up with a new formula for calculating the power spectrum uncertainties. This is crucial in the case of non-stationary short-lived processes affected by uncorrelated statistical noise, for which ensemble averaging does not make any physical sense.

  8. The Irradiation Origin of Beryllium Radioisotopes and Other Short-lived Radionuclides

    NASA Astrophysics Data System (ADS)

    Gounelle, Matthieu; Shu, Frank H.; Shang, Hsien; Glassgold, A. E.; Rehm, K. E.; Lee, Typhoon

    2006-04-01

    Two explanations exist for the short-lived radionuclides (T1/2<=5 Myr) present in the solar system when the calcium-aluminum-rich inclusions (CAIs) first formed. They originated either from the ejecta of a supernova or by the in situ irradiation of nebular dust by energetic particles. With a half-life of only 53 days, 7Be is then the key discriminant, since it can be made only by irradiation. Using the same irradiation model developed earlier by our group, we calculate the yield of 7Be. Within model uncertainties associated mainly with nuclear cross sections, we obtain agreement with the experimental value. Moreover, if 7Be and 10Be have the same origin, the irradiation time must be short (a few to tens of years), and the proton flux must be of order F~2×1010 cm-2 s-1. The X-wind model provides a natural astrophysical setting that gives the requisite conditions. In the same irradiation environment, 26Al, 36Cl, and 53Mn are also generated at the measured levels within model uncertainties, provided that irradiation occurs under conditions reminiscent of solar impulsive events (steep energy spectra and high 3He abundance). The decoupling of the 26Al and 10Be observed in some rare CAIs receives a quantitative explanation when rare gradual events (shallow energy spectra and low 3He abundance) are considered. The yields of 41Ca are compatible with an initial solar system value inferred from the measured initial 41Ca/40Ca ratio and an estimate of the thermal metamorphism time (from Young et al.), alleviating the need for two-layer proto-CAIs. Finally, we show that the presence of supernova-produced 60Fe in the solar accretion disk does not necessarily mean that other short-lived radionuclides have a stellar origin.

  9. "Unattached" fraction of short-lived Rn decay products in indoor and outdoor environments: an improved single-screen method and results.

    PubMed

    Reineking, A; Porstendörfer, J

    1990-06-01

    The unattached fraction fp of potential alpha energy of short-lived Rn decay products was measured under realistic, natural conditions in different dwellings and in the open atmosphere by a single-screen technique. An improved data evaluation method was developed where the measured activities of 218Po (RaA) and 214Pb (RaB) were corrected by the screen-attached activities of 214Bi (214Po) [RaC (RaC')]. This method is based on the experimental observation that the 214Bi (214Po) unattached activities are negligible under realistic living conditions and that the size distributions of the aerosol-attached activities of all short-lived Rn daughters are identical. In closed rooms without additional aerosol sources, a mean unattached fraction fp of the potential alpha energy of 0.096 was obtained at a mean aerosol particle concentration of 6100 cm-3 and at a mean equilibrium factor F of 0.30. This mean fp value is about three times higher than the value used in the literature for the radiation exposure calculation of the human public. In closed rooms with additional aerosol sources (cigarette smoke, heating systems, aerosols from a burning candle), the aerosol particle concentrations ranged up to 10(6) cm-3 and the attachment rates, X, increased up to 1000 h-1. The fp values sometimes decreased below the detection limit of 0.005, and the F values increased to as high as 0.77. In the ambient atmosphere in the vicinity of Göttingen, a mean unattached fraction fp of 0.02 and a mean aerosol particle concentration of 3.4 x 10(4) cm-3 were measured at 1 m above the ground. The mean equilibrium factor F was determined to be 0.7. PMID:2160922

  10. Uncertainties and constraints regarding the contribution of very short-lived substances to stratospheric bromine loading

    NASA Astrophysics Data System (ADS)

    Aschmann, Jan; Sinnhuber, Björn-Martin

    2013-04-01

    A major factor of uncertainty in the assessment of stratospheric bromine loading is the unclear role of very short-lived substances (VSLS). One of the major obstacles for short-lived source gases in contributing to the stratosphere is generally thought to be the loss of inorganic bromine (Bry) in the tropical tropopause layer due to dehydration. Besides the dehydration process itself, transportation pathways and velocities are also of vital importance as they influence the partitioning between mostly insoluble organic source gases and partly soluble inorganic degradation products. To investigate this complex system we employ an extensive set of sensitivity calculations with a three-dimensional chemistry transport model comprising a consistent parameterization of convective transport and a comprehensive chemistry scheme. The model considers the two most important bromine VSLS, bromoform (CHBr3) and dibromomethane (CH2Br2) assuming a fixed and uniform detrainment mixing ratio of 1 pptv each. Despite our simplified approach our model agrees reasonably well with available observations of bromine source and product gases. We find that source gas injection is the dominant pathway for VSLS into the stratosphere; about 50% of CHBr3 and 93% of CH2Br2 is able to overcome the cold point tropopause at approximately 17 km altitude, modulated by the inter-annual variability of the vertical transport efficiency. In fact, our sensitivity calculations indicate that the extent of source gas injection of CHBr3 is highly sensitive to the strength of convection and large-scale ascent; in contrast, modifying the photolysis or the destruction via OH yields a significantly smaller response. The next important aspect we identified is that the partitioning of available Bry from short-lived sources is clearly shifted away from HBr, according to our current state of knowledge the only member of the Bry family which is efficiently adsorbed on ice particles. This effect is caused by very efficient heterogeneous reactions on ice surfaces which reduce the HBr/Bry fraction below 15% at the tropical tropopause. Under these circumstances there is no significant loss of Bry due to dehydration in the model; VSLS contribute fully to stratospheric bromine. In addition, we conduct several sensitivity calculations to test the robustness of this result. The loss of inorganic bromine is not very sensitive to moderate changes of the involved parameters such as the abundance of water vapor, sedimentation velocity of particles or ice uptake coefficients. However, dehydration may play a minor role for Bry removal under the assumption that HOBr is efficiently adsorbed on ice as well since the heterogeneous reactions alter the partitioning equilibrium of Bry in favor of HOBr (up to 12% loss of bromine from VSLS). Even in the extreme and unrealistic case that adsorbed species on ice particles are instantaneously removed the maximum loss of bromine does not exceed 25%.

  11. Chemical characterization of soot particles emitted by Wood-Burning Cook Stoves: A XPS and HRTEM study

    NASA Astrophysics Data System (ADS)

    Carabali, Giovanni; Peralta, Oscar; Castro, Telma; Torres, Ricardo; Ruiz, Gerardo; Molina, Luisa; Saavedra, Isabel

    2014-05-01

    The morphology, microstructure, chemical composition, and electronic structure of soot particles emitted directly from biofuel cook stoves have been studied by high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). In order to obtain freshly emitted soot particles, copper grids for Transmission Electron Microscope (TEM) were placed on the last two of an 8-stages MOUDI cascade impactor. The analysis of HRTEM micrographs revealed the nanostructure and the particle size of soot chain. Additionally, the morphology of soot particles was analyzed calculating the border-based fractal dimension (Df). Particles sampled on the first heating stage exhibit complex shapes with high values of Df, which are present as aggregates formed by carbon ceno-spheres. The XPS survey spectrum for soot particles shows that the main particle composition is carbon. We also observed differences in the carbon/oxygen (C/O) ratio of the particles, which probably depends on the combustion process efficiency of each cook-stove analyzed. The XPS C-1s spectra show carbon with two peaks that correspond to sp2 and sp3 hybridization. Also, real-time absorption (?a) and scattering (?s) coefficients of the particles emitted by cook stoves were measured. The trend in ?a and ?s indicate that the cooking process has two important combustion stages which varied in its flaming strength, being vigorous in the first stage and soft in the second one.

  12. Volatile properties of particles emitted by compressed natural gas and diesel buses during steady-state and transient driving modes.

    PubMed

    Jayaratne, E R; Meyer, N K; Ristovski, Z D; Morawska, L

    2012-01-01

    Volatile properties of particle emissions from four compressed natural gas (CNG) and four diesel buses were investigated under steady-state and transient driving modes on a chassis dynamometer. The exhaust was diluted utilizing a full-flow continuous volume sampling system and passed through a thermodenuder at controlled temperature. Particle number concentration and size distribution were measured with a condensation particle counter and a scanning mobility particle sizer, respectively. We show that while almost all the particles emitted by the CNG buses were in the nanoparticle size range, at least 85% and 98% were removed at 100 and 250 °C, respectively. Closer analysis of the volatility of particles emitted during transient cycles showed that volatilization began at around 40 °C, with the majority occurring by 80 °C. Particles produced during hard acceleration from rest exhibited lower volatility than those produced during other times of the cycle. On the basis of our results and the observation of ash deposits on the walls of the tailpipes, we suggest that these nonvolatile particles were composed mostly of ash from lubricating oil. Heating the diesel bus emissions to 100 °C removed ultrafine particle numbers by 69-82% when a nucleation mode was present and just 18% when it was not. PMID:22107263

  13. AGB stars as a source of short-lived radioactive nuclei in the solar nebula

    NASA Technical Reports Server (NTRS)

    Wasserburg, G. J.; Gallino, R.; Busso, M.; Raiteri, C. M.

    1993-01-01

    The purpose is to estimate the possible contribution of some short-lived nuclei to the early solar nebula from asymptotic giant branch (AGB) sources. Low mass (1 to 3 solar mass) AGB stars appear to provide a site for synthesis of the main s process component for solar system material with an exponential distribution of neutron irradiations varies as exp(-tau/tau(sub 0)) (where tau is the time integrated neutron flux with a mean neutron exposure tau(sub 0)) for solar abundances with tau(sub 0) = 0.28 mb(sup -1). Previous workers estimated the synthesis of key short-lived nuclei which might be produced in AGB stars. While these calculations exhibit the basic characteristics of nuclei production by neutron exposure, there is need for a self-consistent calculation that follows AGB evolution and takes into account the net production from a star and dilution with the cloud medium. Many of the general approaches and the conclusions arrived at were presented earlier by Cameron. The production of nuclei for a star of 1.5 solar mass during the thermal pulsing of the AGB phase was evaluated. Calculations were done for a series of thermal pulses with tau(sub 0) = 0.12 and 0.28 mb(sup -1). These pulses involve s nucleosynthesis in the burning shell at the base of the He zone followed by the ignition of the H burning shell at the top of the He zone. After about 10-15 cycles the abundances of the various nuclei in the He zone become constant. Computations of the abundances of all nuclei in the He zone were made following Gallino. The mass of the solar nebula was considered to consist of some initial material of approximately solar composition plus some contributions from AGB stars. The ratios of the masses required from the AGB He burning zone to the ISM necessary to produce the observed value of Pd-107/Pd-108 in the early solar system were calculated and this dilution factor was applied to all other relevant nuclei.

  14. The impacts of short-lived ozone precursors on climate and air quality

    NASA Astrophysics Data System (ADS)

    Fry, Meridith McGee

    Human emissions of short-lived ozone precursors not only degrade air quality and health, but indirectly affect climate via chemical effects on ozone, methane, and aerosols. Some have advocated for short-lived air pollutants in near-term climate mitigation strategies, in addition to national air quality programs, but their radiative forcing (RF) impacts are uncertain and vary based on emission location. In this work, global chemical transport modeling is combined with radiative transfer modeling to study the impacts of regional ozone precursor emissions (NOx, CO, and NMVOCs) on climate, via changes in ozone, methane, and sulfate, and on regional and global air quality. The first study evaluates NOx, CO, and NMVOC emission reductions from four regions across an ensemble of models, finding that NMVOC and CO reductions from all four regions cool climate (negative RF) by decreasing ozone and methane, while improving air quality. NOx and NMVOC global warming potentials (GWPs), a measure of the relative radiative effects of individual climate forcers, vary strongly among regions, while CO GWPs show less variability. The second and third studies investigate further the RF and air quality impacts of CO and NMVOC emission reductions from 10 world regions. The greatest benefits to RF and air quality (per unit emissions) are achieved by CO reductions from the tropics, due to more active photochemistry and convection. CO GWPs are fairly independent of the reduction region (GWP20: 3.71 to 4.37; GWP100: 1.26 to 1.44), while NMVOC GWPs are more variable (GWP 20: -1.13 to 18.9; GWP100: 0.079 to 6.05). Accounting for additional forcings from CO and NMVOC emissions would likely change RF and GWP estimates. Regionally-specific GWPs for NOx and NMVOCs and a globally-uniform GWP for CO may allow these gases to be included in a multi-gas emissions trading framework, and enable comprehensive strategies for meeting climate and air quality goals simultaneously. Future research could investigate full climate responses using coupled chemistry-climate models, and perform regional analyses of specific emission control measures to maximize climate and air quality benefits.

  15. Long- and short-lived nuclide constraints on the recent evolution of permafrost soils

    NASA Astrophysics Data System (ADS)

    Bagard, M.; Chabaux, F. J.; Rihs, S.; Pokrovsky, O. S.; Prokushkin, A. S.; Viers, J.

    2011-12-01

    Frozen permafrost ecosystems are particularly sensitive to climate warming, which notably induces a deepening of the active layer (the maximum thawing depth during summer time). As a consequence, geochemical and hydrological fluxes within boreal areas are expected to be significantly affected in the future. Understanding the relationship between environmental changes and permafrost modifications is then a major challenge. This work aims to evaluate in a Siberian watershed the dynamics of the permafrost active layer and their recent modifications by combining a classic study of long-lived nuclides to the study of short-lived nuclides of U and Th decay series. Two soil profiles, located on opposite slopes (north- and south-facing slopes) of the Kulingdakan watershed (Putorana Plateau, Central Siberia), were sampled at several depths within the active layer and (238U), (234U), (232Th), (230Th), (226Ra), (228Ra), (228Th) and (210Pb) were measured on bulk soil samples by TIMS or gamma spectrometry. Our results show that south-facing and north-facing soil profiles are significantly different in terms of evolution of chemical concentrations and nuclide activities; north-facing soil profile is strongly affected by atmospheric inputs whereas long-lived nuclide dynamics within south-facing soil profile are dominated by weathering and exhibit more complex patterns. The amount of above-ground biomass being the single varying parameter between the two slopes of the watershed, we suggest that the structuring of permafrost active layer is very sensitive to vegetation activity and that the functioning of boreal soils will be significantly modified by its development due to more favorable climatic conditions. Moreover, the coupling of long and short-lived nuclides highlights the superimposition of a recent mobilization of chemical elements within soils (<10 years) over a much older soil structure (>8000 years), which can be observed for both soil profiles. The shallowest layer of the north-facing soil profile presents a recent increase of Th leaching that we link to the development of vegetation activity and/or organic matter degradation. In contrast, recent changes within south-facing soil profile affect the deepest part of the active layer, suggesting its deepening as a result of a global warming of Siberian soils.

  16. Evaluation of sediment dynamics in coastal systems via short-lived radioisotopes

    NASA Astrophysics Data System (ADS)

    Giffin, Dan; Corbett, D. Reide

    2003-08-01

    The Neuse and Pamlico River Estuaries are shallow, dynamic systems that have been plagued with symptoms of eutrophication over the past two decades. Extensive research has been conducted over the last 5-10 years to better understand the complex nutrient dynamics of these systems. However, most of these studies have concentrated on nutrient cycling in the water column. Only recently have studies focused on the benthic environment, and most sediment studies have neglected the dynamic nature of the benthos, focusing instead on diffusion as the dominant transport process delivering nutrients to the water column. Although diffusion of nutrients across the sediment-water interface may be important during quiescent periods of sediment deposition and short-term storage, wind events associated with storms throughout the year will resuspend newly deposited sediments resulting in the advective transport of sediment porewater, rich with nitrogen, phosphorus and carbon, into the water column. Sediment resuspension may increase water column nutrient concentrations, and therefore present estimates of nutrient and carbon inputs from the sediments may be too low. This study evaluated short-term sediment dynamics of natural resuspension events and deposition rates in these two estuaries with the use of short-lived radioisotopes, 7Be, 137Cs, and 234Th. Sediment cores at nine sites in the estuaries have been collected at least bimonthly since May 2001. In general, tracers indicate a depositional environment with minimal episodes of removal. The largest sediment removal occurred in August 2001 in the Neuse River where an estimated 2.2 cm of sediment were removed over the previous 6-week period. This removal mechanism essentially advects porewater nutrients into the water column. Calculated advective fluxes of ammonium and phosphate based on this resuspension event were approximately six times greater than the average diffusive flux measured in the same general area of the river. Longer-term deposition rates, using 137Cs, ranged from 1.4 to greater than 5 mm year -1, comparable to earlier studies in the area and agree well with the interpretation of the short-lived tracers. In addition, meteorological (wind speed and direction), turbidity, and bottom current data were collected and indicated that these resuspension events occur when passing fronts developed wind speeds in excess of 4 m s -1 with rapid shifts in direction. Currents exhibited estuarine flow reversals associated with wind events and apparently have some control over the sediment removal processes.

  17. Age-dependent decline in fin regenerative capacity in the short-lived fish Nothobranchius furzeri.

    PubMed

    Wendler, Sebastian; Hartmann, Nils; Hoppe, Beate; Englert, Christoph

    2015-10-01

    The potential to regenerate declines with age in a wide range of organisms. A popular model system to study the mechanisms of regeneration is the fin of teleost fish, which has the ability to fully regrow upon amputation. Here, we used the short-lived killifish Nothobranchius furzeri to analyse the impact of aging on fin regeneration in more detail. We observed that young fish were able to nearly completely (98%) regenerate their amputated caudal fins within 4 weeks, whereas middle-aged fish reached 78%, old fish 57% and very old fish 46% of their original fin size. The difference in growth rate between young and old fish was already significant at 3 days post amputation (dpa) and increased with time. We therefore hypothesized that early events are crucial for the age-related differences in regenerative capacity. Indeed, we could observe a higher percentage of proliferating cells in early regenerating fin tissue of young fish compared with aged fish and larger fractions of apoptotic cells in aged fish. Furthermore, young fish showed peak upregulation of several genes involved in fgf and wnt/β-catenin signalling at an earlier time point than old fish. Our findings suggest that regenerative processes are initiated earlier and that regeneration overall is more efficient in younger fish. PMID:26121607

  18. Ubiquitin-mediated proteolysis of a short-lived regulatory protein depends on its cellular localization.

    PubMed

    Lenk, U; Sommer, T

    2000-12-15

    In this study we demonstrate that the Deg1 degradation signal of the transcriptional repressor Matalpha2 confers compartment-specific turnover to a reporter protein. Rapid degradation of a Deg1-containing fusion protein is observed only when the reporter is efficiently imported into the nucleus. In contrast, a reporter that is constantly exported from the nucleus exhibits an extended half-life. Furthermore, nuclear import functions are crucial for both Deg1-induced degradation as well as for the turnover of the endogenous Matalpha2 protein. The conjugation of ubiquitin to a Deg1-containing reporter protein is abrogated in mutants affected in nuclear import. Obviously, the Deg1 signal initiates rapid proteolysis within the nucleoplasm, whereas in the cytosol it mediates turnover via a slower pathway. In both pathways the ubiquitin-conjugating enzymes Ubc6p/Ubc7p play a pivotal role. These observations imply that both the cellular targeting of a substrate and the compartment-specific activity of components of the ubiquitin-proteasome system define the half-life of naturally short-lived proteins. PMID:10991948

  19. Counteracting the climate effects of volcanic eruptions using short-lived greenhouse gases

    NASA Astrophysics Data System (ADS)

    Samset, B. H.; Fuglestvedt, J.; Shine, K. P.

    2014-12-01

    A large volcanic eruption might constitute a climate emergency, significantly altering global temperature and precipitation for several years. Major future eruptions will occur, but their size or timing cannot be predicted. How could global society prepare for, and react to, such emergencies? One possibility is deliberate, coordinated emissions of short-lived greenhouse gases, along a pathway designed to match the climate responses to the eruption. We estimate such an emission pathway, countering a hypothetical eruption three times the size of Mt Pinatubo in 1991. Using a global climate model to evaluate global and regional responses to the eruption, with and without counter emissions, we show that it may be possible to counteract its climate effects, significantly dampening the abrupt impact of the eruption. We then raise practical, financial and ethical aspects related to such a strategy. Designed emissions to counter temporary global cooling would not have the disadvantages associated with more commonly discussed geoengineering to avoid long-term warming. Nevertheless, implementation would still face significant challenges.

  20. Telomeres shorten while Tert expression increases during ageing of the short-lived fish Nothobranchius furzeri.

    PubMed

    Hartmann, Nils; Reichwald, Kathrin; Lechel, André; Graf, Michael; Kirschner, Jeanette; Dorn, Alexander; Terzibasi, Eva; Wellner, Juliane; Platzer, Matthias; Rudolph, Karl Lenhard; Cellerino, Alessandro; Englert, Christoph

    2009-05-01

    Age research in vertebrates is often limited by the longevity of available models. The teleost fish Nothobranchius furzeri has an exceptionally short lifespan with 3.5 months for the laboratory strain GRZ and about 6 months for the wild-derived strain MZM-0403. Here we have investigated telomere length in muscle and skin tissue of young and old fish of both strains using different methods. We found age-dependent telomere shortening in the MZM-0403 strain with the longer lifespan, whereas the short-lived GRZ strain showed no significant telomere shortening with advanced age. Sequencing of the two main telomerase genes Tert and Terc revealed that both genes are highly conserved between the N. furzeri strains while there is little conservation to other fish species and humans. Both genes are ubiquitously expressed in N. furzeri and expression levels of Tert and Terc correlate with telomerase activity in a tissue-specific manner. Unexpectedly, the expression level of Tert is increased in aged muscle and skin tissue of MZM-0403 suggesting that telomeres shorten upon ageing despite increased Tert expression and hence high telomerase activity. We further conclude that the extremely short lifespan of the GRZ strain is not caused by diminished telomerase activity or accelerated telomere shortening. PMID:19428446

  1. Age-dependent decline in fin regenerative capacity in the short-lived fish Nothobranchius furzeri

    PubMed Central

    Wendler, Sebastian; Hartmann, Nils; Hoppe, Beate; Englert, Christoph

    2015-01-01

    The potential to regenerate declines with age in a wide range of organisms. A popular model system to study the mechanisms of regeneration is the fin of teleost fish, which has the ability to fully regrow upon amputation. Here, we used the short-lived killifish Nothobranchius furzeri to analyse the impact of aging on fin regeneration in more detail. We observed that young fish were able to nearly completely (98%) regenerate their amputated caudal fins within 4 weeks, whereas middle-aged fish reached 78%, old fish 57% and very old fish 46% of their original fin size. The difference in growth rate between young and old fish was already significant at 3 days post amputation (dpa) and increased with time. We therefore hypothesized that early events are crucial for the age-related differences in regenerative capacity. Indeed, we could observe a higher percentage of proliferating cells in early regenerating fin tissue of young fish compared with aged fish and larger fractions of apoptotic cells in aged fish. Furthermore, young fish showed peak upregulation of several genes involved in fgf and wnt/β-catenin signalling at an earlier time point than old fish. Our findings suggest that regenerative processes are initiated earlier and that regeneration overall is more efficient in younger fish. PMID:26121607

  2. A platform for rapid exploration of aging and diseases in a naturally short-lived vertebrate

    PubMed Central

    Harel, Itamar; Benayoun, Bérénice A.; Machado, Ben; Singh, Param Priya; Hu, Chi-Kuo; Pech, Matthew F.; Valenzano, Dario R.; Zhang, Elisa; Sharp, Sabrina C.; Artandi, Steven E.; Brunet, Anne

    2015-01-01

    Summary Aging is a complex process that affects multiple organs. Modeling aging and age-related diseases in the lab is challenging because classical vertebrate models have relatively long lifespans. Here we develop the first platform for rapid exploration of age-dependent traits and diseases in vertebrates, using the naturally short-lived African turquoise killifish. We provide an integrative genomic and genome-editing toolkit in this organism using our de novo-assembled genome and the CRISPR/Cas9 technology. We mutate many genes encompassing the hallmarks of aging, and for a subset, we produce stable lines within 2–3 months. As a proof-of-principle, we show that fish deficient for the protein subunit of telomerase exhibit the fastest onset of telomere-related pathologies among vertebrates. We further demonstrate the feasibility of creating specific genetic variants. This genome-to-phenotype platform represents a unique resource for studying vertebrate aging and disease in a high throughput manner and for investigating candidates arising from human genome-wide studies. PMID:25684364

  3. Observation and modeling of short-lived oxygenated hydrocarbons in the tropical free troposphere

    NASA Astrophysics Data System (ADS)

    Volkamer, Rainer; Apel, Eric

    2013-04-01

    The Tropical Ocean tRoposphere Exchange experiment TORERO (Jan/Feb 2012) probed the influence of air-sea exchange of organic carbon species and very short lived halogen species on the oxidative capacity of the tropical free troposphere over the full tropospheric air column above the eastern tropical Pacific Ocean. Organic carbon is important in the atmosphere, because it influences the reactive chemistry and lifetime of climate active gases (e.g., methane, ozone, dimethyl sulfide), and because of its relevance for the formation, composition and climate impact of aerosols. This presentation summarizes unequivocal evidence for the presence of numerous oxygenated hydrocarbons (i.e., glyoxal, formaldehyde, acetaldehyde, propanal, MVK, MEK, aliphatic aldehydes, alcohols etc.) in the remote marine boundary layer, and in the tropical free troposphere. These species were detected by means of both Differential Optical Absorption Spectroscopy (Airborne MAX-DOAS), and online GC-MS (TOGA) aboard the NSF/NCAR GV aircraft. We employ atmospheric modeling constrained by observations of gas-phase hydrocarbons, aerosols, photolysis frequencies, and meterological parameters measured aboard the plane to elucidate the formation mechanism of this as of yet unaccounted source for oxidized organic carbon, and quantify the influence on the OVOCs on hydroxyl, bromine, chlorine and iodine radical abundances.

  4. Developments in precison mass measurements of short-lived r-process nuclei with CARIBU

    NASA Astrophysics Data System (ADS)

    Marley, S. T.; Aprahamian, A.; Mumpower, M.; Nystrom, A.; Paul, N.; Siegl, K.; Strauss, S.; Surman, R.; Clark, J. A.; Perez Galvan, A.; Savard, G.; Morgan, G.; Orford, R.

    2013-10-01

    The confluence of new radioactive beam facilities and modern precision mass spectrometry techniques now make it possible to measure masses of many neutron-rich nuclei important to nuclear structure and astrophysics. A recent mass sensitivity study (S. Brett et al., Eur. Phys. J., A 48, 184 (2012)) identified the nuclear masses that are the most influential to the final rapid-neutron capture process abundance distributions under various astrophysical scenarios. This work motivated a campaign of precision mass measurements using the Canadian Penning Trap (CPT) installed at the Californium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne National Laboratory. In order to measure the weakest and most short-lived (t1/2 < 150 ms) of these influential nuclei, a series of upgrades to the CARIBU and CPT systems have been developed. The implementation of these upgrades, the r-process mass measurements, and the status of CARIBU facilty will be discussed. This work performed under the auspices of NSERC, Canada, appl. # 216974, the U.S. DOE, Office of Nuclear Physics, under contracts DE-AC02-06CH11357, DE-FG02-91ER-40609, DE-FG02-98ER41086, & DE-AC52-07NA27344, and NSF Grants PHY08-22648 and PHY-106819.

  5. Spatial distribution of brominated very short-lived substances in the eastern Pacific

    NASA Astrophysics Data System (ADS)

    Liu, Yina; Yvon-Lewis, Shari A.; Thornton, Daniel C. O.; Campbell, Lisa; Bianchi, Thomas S.

    2013-05-01

    Seawater concentrations and distributions of brominated very short-lived substances (BrVSLS), including bromoform (CHBr3), dibromomethane (CH2Br2), bromodichloromethane (CHBrCl2), chlorodibromomethane (CHClBr2), were measured in the upper water column (5-750 m) in the eastern Pacific. Inorganic nutrient, pigment concentrations, and picoplankton cell counts were measured to determine biogeochemical factors that affect the production and distribution of these BrVSLS. Elevated concentrations of BrVSLS were observed in coastal and tropical seawater. Concentration maxima for CHBr3, CH2Br2, and CHClBr2 were observed below the mixed layer, near the subsurface chlorophyll a maxima, which suggest BrVSLS production may be related to photosynthetic biomass production. Our results also suggest that heterotrophic bacteria may also contribute to CH2Br2 and CHBrCl2 production in the water column. The maximum CHBrCl2 concentration was observed at a depth much deeper than the euphotic zone, which suggests sources other than photosynthetic biomass. Elevated CHBrCl2 concentrations in deeper waters were coincident with elevated CHCl3 concentrations, which may be an evidence for successive chlorine substitution of CHBr3 in deeper and older water masses.

  6. Dissolved organic matter composition drives the marine production of brominated very short-lived substances.

    PubMed

    Liu, Yina; Thornton, Daniel C O; Bianchi, Thomas S; Arnold, William A; Shields, Michael R; Chen, Jie; Yvon-Lewis, Shari A

    2015-03-17

    Brominated very short-lived substances (BrVSLS), such as bromoform, are important trace gases for stratospheric ozone chemistry. These naturally derived trace gases are formed via bromoperoxidase-mediated halogenation of dissolved organic matter (DOM) in seawater. Information on DOM type in relation to the observed BrVSLS concentrations in seawater, however, is scarce. We examined the sensitivity of BrVSLS production in relation to the presence of specific DOM moieties. A total of 28 model DOM compounds in artificial seawater were treated with vanadium bromoperoxidase (V-BrPO). Our results show a clear dependence of BrVSLS production on DOM type. In general, molecules that comprise a large fraction of the bulk DOM pool did not noticeably affect BrVSLS production. Only specific cell metabolites and humic acid appeared to significantly enhance BrVSLS production. Amino acids and lignin phenols suppressed enzyme-mediated BrVSLS production and may instead have formed halogenated nonvolatile molecules. Dibromomethane production was not observed in any experiments, suggesting it is not produced by the same pathway as the other BrVSLS. Our results suggest that regional differences in DOM composition may explain the observed BrVSLS concentration variability in the global ocean. Ultimately, BrVSLS production and concentrations are likely affected by DOM composition, reactivity, and cycling in the ocean. PMID:25723123

  7. Simulating the impact of emissions of brominated very short lived substances on past stratospheric ozone trends

    NASA Astrophysics Data System (ADS)

    Sinnhuber, Björn-Martin; Meul, Stefanie

    2015-04-01

    Bromine from very short lived substances (VSLS), primarily from natural oceanic sources, contributes substantially to the stratospheric bromine loading. This source of stratospheric bromine has so far been ignored in most chemistry climate model calculations of stratospheric ozone trends. Here we present a transient simulation with the chemistry climate model EMAC for the period 1960-2005 including emissions of the five brominated VSLS CHBr3, CH2Br2, CH2BrCl, CHBrCl2, and CHBr2Cl. The emissions lead to a realistic stratospheric bromine loading of about 20 pptv for present-day conditions. Comparison with a standard model simulation without VSLS shows large differences in modeled ozone in the extratropical lowermost stratosphere and in the troposphere. Differences in ozone maximize in the Antarctic Ozone Hole, resulting in more than 20% less ozone when VSLS are included. Even though the emissions of VSLS are assumed to be constant in time, the model simulation with VSLS included shows a much larger ozone decrease in the lowermost stratosphere during the 1979-1995 period and a faster ozone increase during 1996-2005, in better agreement with observed ozone trends than the standard simulation without VSLS emissions.

  8. Short-Lived Buildings in China: Impacts on Water, Energy, and Carbon Emissions.

    PubMed

    Cai, Wenjia; Wan, Liyang; Jiang, Yongkai; Wang, Can; Lin, Lishen

    2015-12-15

    This paper has changed the vague understanding that "the short-lived buildings have huge environmental footprints (EF)" into a concrete one. By estimating the annual floor space of buildings demolished and calibrating the average building lifetime in China, this paper compared the EF under various assumptive extended buildings' lifetime scenarios based on time-series environmental-extended input-output model. Results show that if the average buildings' lifetime in China can be extended from the current 23.2 years to their designed life expectancy, 50 years, in 2011, China can reduce 5.8 Gt of water withdrawal, 127.1 Mtce of energy consumption, and 426.0 Mt of carbon emissions, each of which is equivalent to the corresponding annual EF of Belgium, Mexico, and Italy. These findings will urge China to extend the lifetime of existing and new buildings, in order to reduce the EF from further urbanization. This paper also verifies that the lifetime of a product or the replacement rate of a sector is a very important factor that influences the cumulative EF. When making policies to reduce the EF, adjusting people's behaviors to extend the lifetime of products or reduce the replacement rate of sectors may be a very simple and cost-effective option. PMID:26561867

  9. Harvard-MIT research program in short-lived radiopharmaceuticals. Final report

    SciTech Connect

    Adelstein, S.J.

    1995-02-01

    The Harvard-MIT Research Program in Short-lived Radiopharmaceuticals was established in 1977 to foster interaction among groups working in radiopharmaceutical chemistry at Harvard Medical School, the Massachusetts Institute of Technology, and the Massachusetts General Hospital. To this was added a group at The Childrens Hospital. From these collaborations and building upon the special strengths of the participating individuals, laboratories and institutions, it was hoped that original approaches would be found for the design of new, clinically useful, radiolabeled compounds. The original thrust of this proposal included: (a) examination of the coordination chemistry of technetium as a basis for rational radiopharmaceutical design, (b) development of an ultrashort-lived radionuclide generator for the diagnosis of congenital heart disease in newborns, (c) synthesis of receptor-site-directed halopharmaceuticals, (d) improved facile labeling of complex molecules with positron-emitting radionuclides. The authors` 1986 proposal was oriented toward organs and disease, emphasizing radiolabeled agents that delineate specific functions and the distribution of receptors in brain, heart, and tumors. In 1989, they further refined their purposes and focused on two major aims: (a) synthesis and utilization of neutral technetium and rhenium complexes of high specific activity, and (b) development of new approaches to the radiolabeling of proteins, peptides, immunoglobulins, and their fragments. In 1992, the authors amended this proposal to concentrate their efforts on biologically active peptides and proteins for targeted radiodiagnosis and therapy.

  10. Short-Lived HF Molecules in Superionic Hydrogen Fluoride at Extreme Conditions

    NASA Astrophysics Data System (ADS)

    Tsumuraya, Kazuo; Ohde, Yoshiyuki; Oshimi, Tadaaki

    2015-02-01

    The first principles molecular dynamics study enables us to elucidate the existence of short-lived HF molecules in the superionic hydrogen fluoride at an extreme high pressure and a temperature. Three fourth of the immobile fluorines constructs the molecules with lifetime of 8 fs. The ionized fluorines form weak HF bond with the proton in the nearest HF molecule of which the lifetime is 3 fs. The covalent and the Coulomb bonds between the fluorines and the protons form indirect covalent and indirect Coulomb attractions between the di-interstitial protons on the mid-fluorines. The attractions reduce the Haven's ratio of the protons. The absence of the proton dimers indicates a failure of the caterpillar diffusion model or the Frenkel-Kontorova chain model for the superionic diffusion of the protons. The incompletely ionized cations and anions reduce their Coulomb attractions which induce the sublattice melting of smaller size and smaller mass of the protons than the fluorines. The electronic states of the fluoride are intermediate between the ionic crystals and the covalent bonded molecular crystals. The superionic conductors are classified into three groups: they are molecular type, covalent metalloid type, and metallic type conductors.

  11. Saving the Cryosphere in the Arctic and the Himalayas: Mitigation of Short Lived Climate Pollutants

    NASA Astrophysics Data System (ADS)

    Ramanathan, V.

    2012-12-01

    Observations reveal that the polar warming is hastened by the pole ward retreat of the extra-tropical storm track clouds and the sea-ice albedo feedback. The cloud systems associated with the storm tracks are the dominant radiative cooling cloud systems in the planet and their retreat adds more solar energy to the extra-tropical oceans. This is further amplified by the observed reduction in the arctic albedo due to the retreat of the sea-ice. Complicating this situation is the darkening of the arctic cryosphere by black carbon deposition. Over the Himalayas on the other hand, the thermo dynamical feedback involving water vapor amplifies surface warming over the elevated regions of Himalayas-Tibet by factors ranging from1 .5 to 2. This elevated warming is further amplified by black carbon in two distinctly different ways: First absorption of solar radiation in the atmosphere by black carbon has been shown to warm the layers above 5 km by as much as the warming due to CO2. Next, long range transport of black carbon, leads to deposition of black carbon over the bright snow and ice darkens them and enhances the absorption of intense tropical solar radiation over the Himalayas. After summarizing recent observations over the arctic and the Himalayas, we will show how mitigation of the four short lived climate pollutants (methane, black carbon, ozone and HFCs) can significantly slow down the arctic warming and the large warming observed over the elevated regions of the Himalayas-Tibet.

  12. New Short-Lived Isotope ^{221}U and the Mass Surface Near N=126.

    PubMed

    Khuyagbaatar, J; Yakushev, A; Düllmann, Ch E; Ackermann, D; Andersson, L-L; Block, M; Brand, H; Cox, D M; Even, J; Forsberg, U; Golubev, P; Hartmann, W; Herzberg, R-D; Heßberger, F P; Hoffmann, J; Hübner, A; Jäger, E; Jeppsson, J; Kindler, B; Kratz, J V; Krier, J; Kurz, N; Lommel, B; Maiti, M; Minami, S; Mistry, A K; Mrosek, Ch M; Pysmenetska, I; Rudolph, D; Sarmiento, L G; Schaffner, H; Schädel, M; Schausten, B; Steiner, J; De Heidenreich, T Torres; Uusitalo, J; Wegrzecki, M; Wiehl, N; Yakusheva, V

    2015-12-11

    Two short-lived isotopes ^{221}U and ^{222}U were produced as evaporation residues in the fusion reaction ^{50}Ti+^{176}Yb at the gas-filled recoil separator TASCA. An α decay with an energy of E_{α}=9.31(5)  MeV and half-life T_{1/2}=4.7(7)  μs was attributed to ^{222}U. The new isotope ^{221}U was identified in α-decay chains starting with E_{α}=9.71(5)  MeV and T_{1/2}=0.66(14)  μs leading to known daughters. Synthesis and detection of these unstable heavy nuclei and their descendants were achieved thanks to a fast data readout system. The evolution of the N=126 shell closure and its influence on the stability of uranium isotopes are discussed within the framework of α-decay reduced width. PMID:26705628

  13. Highly heterogeneous, activated and short-lived regulatory T cells during chronic filarial infection

    PubMed Central

    Metenou, Simon; Coulibaly, Yaya I.; Sturdevant, Daniel; Dolo, Housseini; Diallo, Abdallah A.; Soumaoro, Lamine; Coulibaly, Michel E.; Kanakabandi, Kishore; Porcella, Stephen F.; Klion, Amy D.; Nutman, Thomas B.

    2016-01-01

    The mechanisms underlying the increase in the numbers of regulatory T (Treg) cells in chronic infection settings remain unclear. Here we have delineated the phenotype and transcriptional profiles of Treg cells from 18 filarial-infected (Fil+) and 19 filarial-uninfected (Fil-) subjects. We found that the frequencies of Foxp3+ Treg cells expressing CTLA-4, GITR, LAG-3 and IL-10 were significantly higher in Fil+ subjects compared with that in Fil- subjects. Foxp3-expressing Treg-cell populations in Fil+ subjects were also more heterogeneous and had higher expression of IL-10, CCL-4, IL-29, CTLA-4 and TGF-β than Fil- subjects, each of these cytokines having been implicated in immune suppression. Moreover, Foxp3-expressing Treg cells from Fil+ subjects had markedly upregulated expression of activation-induced apoptotic genes with concomitant downregulation of those involved in cell survival. To determine whether the expression of apoptotic genes was due to Treg-cell activation, we found that the expression of CTLA-4, CDk8, RAD50, TNFRSF1A, FOXO3 and RHOA were significantly upregulated in stimulated cells compared with unstimulated cells. Taken together, our results suggest that in patent filarial infection, the expanded Treg-cell populations are heterogeneous, short-lived, activated and express higher levels of molecules known to modulate immune responsiveness, suggesting that filarial infection is associated with high Treg-cell turnover. PMID:24737144

  14. Multi-model evaluation of short-lived pollutant distributions over East Asia during summer 2008

    NASA Astrophysics Data System (ADS)

    Quennehen, B.; Raut, J.-C.; Law, K. S.; Ancellet, G.; Clerbaux, C.; Kim, S.-W.; Lund, M. T.; Myhre, G.; Olivié, D. J. L.; Safieddine, S.; Skeie, R. B.; Thomas, J. L.; Tsyro, S.; Bazureau, A.; Bellouin, N.; Daskalakis, N.; Hu, M.; Kanakidou, M.; Klimont, Z.; Kupiainen, K.; Myriokefalitakis, S.; Quaas, J.; Rumbold, S. T.; Schulz, M.; Cherian, R.; Shimizu, A.; Wang, J.; Yoon, S.-C.; Zhu, T.

    2015-04-01

    The ability of six global and one regional model to reproduce distributions of tropospheric ozone and its precursors, as well as aerosols over Asia in summer 2008 is evaluated using satellite and in-situ observations. Whilst ozone precursors (NO2 and CO) are generally underestimated by the models in the troposphere, surface NO2 concentrations are overestimated, suggesting that emissions of NOx are too high. Ozone integrated columns and vertical profiles are generally well modeled, but the global models face difficulties simulating the ozone gradient at the surface between urban and rural environments, pointing to the need to increase model resolution. The accuracy of simulated aerosol patterns over eastern China and northern India varies between the models, and although most of the models reproduce the observed pollution features over eastern China, significant biases are noted in the magnitude of optical properties (aerosol optical depth, aerosol backscatter). These results have important implications for accurate prediction of pollution episodes affecting air quality and the radiative effects of these short-lived climate pollutants over Asia.

  15. Growth in stratospheric chlorine from short-lived chemicals not controlled by the Montreal Protocol

    NASA Astrophysics Data System (ADS)

    Hossaini, R.; Chipperfield, M. P.; Saiz-Lopez, A.; Harrison, J. J.; Glasow, R.; Sommariva, R.; Atlas, E.; Navarro, M.; Montzka, S. A.; Feng, W.; Dhomse, S.; Harth, C.; Mühle, J.; Lunder, C.; O'Doherty, S.; Young, D.; Reimann, S.; Vollmer, M. K.; Krummel, P. B.; Bernath, P. F.

    2015-06-01

    We have developed a chemical mechanism describing the tropospheric degradation of chlorine containing very short-lived substances (VSLS). The scheme was included in a global atmospheric model and used to quantify the stratospheric injection of chlorine from anthropogenic VSLS ( ClyVSLS) between 2005 and 2013. By constraining the model with surface measurements of chloroform (CHCl3), dichloromethane (CH2Cl2), tetrachloroethene (C2Cl4), trichloroethene (C2HCl3), and 1,2-dichloroethane (CH2ClCH2Cl), we infer a 2013 ClyVSLS mixing ratio of 123 parts per trillion (ppt). Stratospheric injection of source gases dominates this supply, accounting for ˜83% of the total. The remainder comes from VSLS-derived organic products, phosgene (COCl2, 7%) and formyl chloride (CHClO, 2%), and also hydrogen chloride (HCl, 8%). Stratospheric ClyVSLS increased by ˜52% between 2005 and 2013, with a mean growth rate of 3.7 ppt Cl/yr. This increase is due to recent and ongoing growth in anthropogenic CH2Cl2—the most abundant chlorinated VSLS not controlled by the Montreal Protocol.

  16. Sizes and shapes of short-lived nuclei via laser spectroscopy. Progress report, May 1, 1980-January 31, 1981

    SciTech Connect

    Lewis, D.A.

    1981-02-01

    The first stage of the program to study the sizes and shapes of short-lived nuclei through their atomic hyperfine structure is to develop a movable laser spectroscopy system. This system is now almost complete and is described in this report along with plans for measurements at Argonne National Laboratory and Brookhaven National Laboratory.

  17. A proposal for assessing study quality: Biomonitoring, Environmental Epidemiology, and Short-lived Chemicals (BEES-C) instrument

    PubMed Central

    LaKind, Judy S.; Sobus, Jon R.; Goodman, Michael; Barr, Dana Boyd; Fürst, Peter; Albertini, Richard J.; Arbuckle, Tye E.; Schoeters, Greet; Tan, Yu-Mei; Teeguarden, Justin; Tornero-Velez, Rogelio; Weisel, Clifford P.

    2015-01-01

    The quality of exposure assessment is a major determinant of the overall quality of any environmental epidemiology study. The use of biomonitoring as a tool for assessing exposure to ubiquitous chemicals with short physiologic half-lives began relatively recently. These chemicals present several challenges, including their presence in analytical laboratories and sampling equipment, difficulty in establishing temporal order in cross-sectional studies, short- and long-term variability in exposures and biomarker concentrations, and a paucity of information on the number of measurements required for proper exposure classification. To date, the scientific community has not developed a set of systematic guidelines for designing, implementing and interpreting studies of short-lived chemicals that use biomonitoring as the exposure metric or for evaluating the quality of this type of research for WOE assessments or for peer review of grants or publications. We describe key issues that affect epidemiology studies using biomonitoring data on short-lived chemicals and propose a systematic instrument – the Biomonitoring, Environmental Epidemiology, and Short-lived Chemicals (BEES-C) instrument – for evaluating the quality of research proposals and studies that incorporate biomonitoring data on short-lived chemicals. Quality criteria for three areas considered fundamental to the evaluation of epidemiology studies that include biological measurements of short-lived chemicals are described: 1) biomarker selection and measurement, 2) study design and execution, and 3) general epidemiological study design considerations. We recognize that the development of an evaluative tool such as BEES-C is neither simple nor non-controversial. We hope and anticipate that the instrument will initiate further discussion/debate on this topic. PMID:25137624

  18. Short-lived nuclei in the early Solar System: Possible AGB sources

    NASA Astrophysics Data System (ADS)

    Wasserburg, G. J.; Busso, M.; Gallino, R.; Nollett, K. M.

    2006-10-01

    The abundances of short-lived radionuclides in the early Solar System (ESS) are reviewed, as well as the methodology used in determining them. These results are compared with the inventory estimated for a uniform galactic production model. It is shown that, to within a factor of two, the observed abundances of 238U, 235U, 232Th, 244Pu, 182Hf, 146Sm, and 53Mn are roughly compatible with long-term galactic nucleosynthesis. 129I is an exception, with an ESS inventory much lower than expected from uniform production. The isotopes 107Pd, 60Fe, 41Ca, 36Cl, 26Al, and 10Be require late addition to the protosolar nebula. 10Be is the product of energetic particle irradiation of the Solar System as most probably is 36Cl. Both of these nuclei appear to be present when 26Al is absent. A late injection by a supernova (SN) cannot be responsible for most of the short-lived nuclei without excessively producing 53Mn; it can however be the source of 53Mn itself and possibly of 60Fe. If a late SN injection is responsible for these two nuclei, then there remains the problem of the origin of 107Pd and several other isotopes. Emphasis is given to an AGB star as a source of many of the nuclei, including 60Fe; this possibility is explored with a new generation of stellar models. It is shown that if the dilution factor (i.e. the ratio of the contaminating mass to the solar parental cloud mass) is f410, a reasonable representation for many nuclei is obtained; this requires that (60Fe/56Fe)ESS 10-7 to 210. The nuclei produced by an AGB source do not include 53Mn, 10Be or 36Cl if it is very abundant. The role of irradiation is discussed with regard to 26Al, 36Cl and 41Ca, and the estimates of bulk solar abundances of these isotopes are commented on. The conflict between various scenarios is emphasized as well as the current absence of an astrophysically plausible global interpretation for all the existing data. Examination of abundances for the actinides indicates that a quiescent interval of 10 yr is required for actinide group production. This is needed in order to explain the data on 244Pu and the new bounds on 247Cm. Because this quiescent interval is not compatible with the 182Hf data, a separate type of r-process event is needed for at least the actinides, distinct from the two types that have previously been identified. The apparent coincidence of the 129I and trans-actinide time scales suggests that the last heavy r contribution was from an r-process that produced very heavy nuclei but without fission recycling so that the yields at Ba and below (including I) were governed by fission.

  19. Convective transport of very-short-lived bromocarbons to the stratosphere

    NASA Astrophysics Data System (ADS)

    Liang, Q.; Atlas, E.; Blake, D.; Dorf, M.; Pfeilsticker, K.; Schauffler, S.

    2014-01-01

    We use the NASA GEOS Chemistry Climate Model (GEOSCCM) to quantify the contribution of two most important brominated very short-lived substances (VSLS), bromoform (CHBr3) and dibromomethane (CH2Br2), to stratospheric bromine and its sensitivity to convection strength. Model simulations suggest that the most active transport of VSLS from the marine boundary layer through the tropopause occurs over the tropical Indian Ocean, the Western Pacific warm pool, and off the Pacific coast of Mexico. Together, convective lofting of CHBr3 and CH2Br2 and their degradation products supplies ∼8 ppt total bromine to the base of the Tropical Tropopause Layer (TTL, ∼150 hPa), similar to the amount of VSLS organic bromine available in the marine boundary layer (∼7.8-8.4 ppt) in the above active convective lofting regions. Of the total ∼8 ppt VSLS-originated bromine that enters the base of TTL at ∼150 hPa, half is in the form of source gas injection (SGI) and half as product gas injection (PGI). Only a small portion (< 10%) the VSLS-originated bromine is removed via wet scavenging in the TTL before reaching the lower stratosphere. On global and annual average, CHBr3 and CH2Br2, together, contribute ∼7.7 pptv to the present-day inorganic bromine in the stratosphere. However, varying model deep convection strength between maximum and minimum convection conditions can introduce a ∼2.6 pptv uncertainty in the contribution of VSLS to inorganic bromine in the stratosphere (BryVSLS). Contrary to the conventional wisdom, minimum convection condition leads to a larger BryVSLS as the reduced scavenging in soluble product gases, thus a significant increase in PGI (2-3 ppt), greatly exceeds the relative minor decrease in SGI (a few 10ths ppt).

  20. Longitudinal analysis of Plantago: adaptive benefits of iteroparity in a short-lived, herbaceous perennial

    PubMed Central

    Shefferson, Richard P.; Roach, Deborah A.

    2010-01-01

    Theory suggests that iteroparity may confer greater fitness than semelparity in situations in which temporal environmental variation is high and unpredictable. Variable age-specific mortality, density dependence, and other factors may also favor iteroparity over semelparity. Here, we empirically test the adaptive benefits of greater numbers of reproductive years in a study of reproductive schedules in an experimental population of a short-lived polycarpic perennial, Plantago lanceolata. A large experimental population was established that included four cohorts with similar genetic structure. Individuals were censused for mortality, size, and reproduction for seven years. Plants experienced variable numbers of reproductive years, but one or two years were most common (~46.7% of the population reproduced only once). The probability of flowering at least once prior to death was determined strongly by extrinsic, environmental or intrinsic but environmentally influenced variables, including early-life size, cohort, and block, but also varied with a number of interactions involving paternal lineage. Maternal effects explained small but significant components of the variance in the number of reproductive years among individuals in each cohort, while paternal effects were significant in only two cohorts. Number of reproductive years contributed significantly to fitness in this system, more so than all other variables tested, although most of the variation in relative fitness may be attributed ultimately to environmental influences. We suggest that the high proportion of each cohort composed of plants reproducing only once may be due to environmental constraints on either growth or size. Such environmental influences, particularly on early life size, may result in small but important indirect effects on fitness. PMID:20392009

  1. Response of Arctic temperature to changes in emissions of short-lived climate forcers

    NASA Astrophysics Data System (ADS)

    Sand, M.; Berntsen, T. K.; von Salzen, K.; Flanner, M. G.; Langner, J.; Victor, D. G.

    2016-03-01

    There is growing scientific and political interest in the impacts of climate change and anthropogenic emissions on the Arctic. Over recent decades temperatures in the Arctic have increased at twice the global rate, largely as a result of ice-albedo and temperature feedbacks. Although deep cuts in global CO2 emissions are required to slow this warming, there is also growing interest in the potential for reducing short-lived climate forcers (SLCFs; refs ,). Politically, action on SLCFs may be particularly promising because the benefits of mitigation are seen more quickly than for mitigation of CO2 and there are large co-benefits in terms of improved air quality. This Letter is one of the first to systematically quantify the Arctic climate impact of regional SLCFs emissions, taking into account black carbon (BC), sulphur dioxide (SO2), nitrogen oxides (NOx), volatile organic compounds (VOCs), organic carbon (OC) and tropospheric ozone (O3), and their transport processes and transformations in the atmosphere. This study extends the scope of previous works by including more detailed calculations of Arctic radiative forcing and quantifying the Arctic temperature response. We find that the largest Arctic warming source is from emissions within the Asian nations owing to the large absolute amount of emissions. However, the Arctic is most sensitive, per unit mass emitted, to SLCFs emissions from a small number of activities within the Arctic nations themselves. A stringent, but technically feasible mitigation scenario for SLCFs, phased in from 2015 to 2030, could cut warming by 0.2 (+/-0.17) K in 2050.

  2. Disentangling the effects of CO2 and short-lived climate forcer mitigation.

    PubMed

    Rogelj, Joeri; Schaeffer, Michiel; Meinshausen, Malte; Shindell, Drew T; Hare, William; Klimont, Zbigniew; Velders, Guus J M; Amann, Markus; Schellnhuber, Hans Joachim

    2014-11-18

    Anthropogenic global warming is driven by emissions of a wide variety of radiative forcers ranging from very short-lived climate forcers (SLCFs), like black carbon, to very long-lived, like CO2. These species are often released from common sources and are therefore intricately linked. However, for reasons of simplification, this CO2-SLCF linkage was often disregarded in long-term projections of earlier studies. Here we explicitly account for CO2-SLCF linkages and show that the short- and long-term climate effects of many SLCF measures consistently become smaller in scenarios that keep warming to below 2 °C relative to preindustrial levels. Although long-term mitigation of methane and hydrofluorocarbons are integral parts of 2 °C scenarios, early action on these species mainly influences near-term temperatures and brings small benefits for limiting maximum warming relative to comparable reductions taking place later. Furthermore, we find that maximum 21st-century warming in 2 °C-consistent scenarios is largely unaffected by additional black-carbon-related measures because key emission sources are already phased-out through CO2 mitigation. Our study demonstrates the importance of coherently considering CO2-SLCF coevolutions. Failing to do so leads to strongly and consistently overestimating the effect of SLCF measures in climate stabilization scenarios. Our results reinforce that SLCF measures are to be considered complementary rather than a substitute for early and stringent CO2 mitigation. Near-term SLCF measures do not allow for more time for CO2 mitigation. We disentangle and resolve the distinct benefits across different species and therewith facilitate an integrated strategy for mitigating both short and long-term climate change. PMID:25368182

  3. Disentangling the effects of CO2 and short-lived climate forcer mitigation

    PubMed Central

    Rogelj, Joeri; Schaeffer, Michiel; Meinshausen, Malte; Shindell, Drew T.; Hare, William; Klimont, Zbigniew; Amann, Markus; Schellnhuber, Hans Joachim

    2014-01-01

    Anthropogenic global warming is driven by emissions of a wide variety of radiative forcers ranging from very short-lived climate forcers (SLCFs), like black carbon, to very long-lived, like CO2. These species are often released from common sources and are therefore intricately linked. However, for reasons of simplification, this CO2–SLCF linkage was often disregarded in long-term projections of earlier studies. Here we explicitly account for CO2–SLCF linkages and show that the short- and long-term climate effects of many SLCF measures consistently become smaller in scenarios that keep warming to below 2 °C relative to preindustrial levels. Although long-term mitigation of methane and hydrofluorocarbons are integral parts of 2 °C scenarios, early action on these species mainly influences near-term temperatures and brings small benefits for limiting maximum warming relative to comparable reductions taking place later. Furthermore, we find that maximum 21st-century warming in 2 °C-consistent scenarios is largely unaffected by additional black-carbon-related measures because key emission sources are already phased-out through CO2 mitigation. Our study demonstrates the importance of coherently considering CO2–SLCF coevolutions. Failing to do so leads to strongly and consistently overestimating the effect of SLCF measures in climate stabilization scenarios. Our results reinforce that SLCF measures are to be considered complementary rather than a substitute for early and stringent CO2 mitigation. Near-term SLCF measures do not allow for more time for CO2 mitigation. We disentangle and resolve the distinct benefits across different species and therewith facilitate an integrated strategy for mitigating both short and long-term climate change. PMID:25368182

  4. MIXING AND TRANSPORT OF SHORT-LIVED AND STABLE ISOTOPES AND REFRACTORY GRAINS IN PROTOPLANETARY DISKS

    SciTech Connect

    Boss, Alan P.

    2013-08-10

    Analyses of primitive meteorites and cometary samples have shown that the solar nebula must have experienced a phase of large-scale outward transport of small refractory grains as well as homogenization of initially spatially heterogeneous short-lived isotopes. The stable oxygen isotopes, however, were able to remain spatially heterogeneous at the {approx}6% level. One promising mechanism for achieving these disparate goals is the mixing and transport associated with a marginally gravitationally unstable (MGU) disk, a likely cause of FU Orionis events in young low-mass stars. Several new sets of MGU models are presented that explore mixing and transport in disks with varied masses (0.016 to 0.13 M{sub Sun }) around stars with varied masses (0.1 to 1 M{sub Sun }) and varied initial Q stability minima (1.8 to 3.1). The results show that MGU disks are able to rapidly (within {approx}10{sup 4} yr) achieve large-scale transport and homogenization of initially spatially heterogeneous distributions of disk grains or gas. In addition, the models show that while single-shot injection heterogeneity is reduced to a relatively low level ({approx}1%), as required for early solar system chronometry, continuous injection of the sort associated with the generation of stable oxygen isotope fractionations by UV photolysis leads to a sustained, relatively high level ({approx}10%) of heterogeneity, in agreement with the oxygen isotope data. These models support the suggestion that the protosun may have experienced at least one FU Orionis-like outburst, which produced several of the signatures left behind in primitive chondrites and comets.

  5. Convection of Very Short Lived Trace Gases into the TTL, UT and LS.

    NASA Astrophysics Data System (ADS)

    Moore, F. L.; Dutton, G. S.; Elkins, J. W.; Hall, B. D.; Hurst, D. F.; Nance, J. D.

    2007-12-01

    The Tropical Tropopause Layer (TTL) can be isolated from the free troposphere for days to a month. Measurements of trace gases with similar local lifetimes of days to a month within the upper troposphere (UT), TTL, and lower stratosphere (LS) can identify convective events and reveal information about primary entry points, possible entrainment, and convective outflow. Episodic evidence of convective transport of Very Short Lived Species (VSLS) from the boundary layer to the UT and LS have been seen before. With CH3I for example, evidence for convection occurs primarily if the dominant convective inflow is from a source region within the boundary layer. This episodic data coupled with the host of measurements in missions like Tropical Composition, Cloud, and Climate Coupling experiment (TC4), will continue to improve our understanding of the convective process. At present, a gap exists between this episodic event driven data and an extrapolation to mean distributions and bulk transport. Trace gases like peroxylacytyl nitrate (PAN) have the potential to bridge this gap and may be more suited for integrated zonal comparisons. PAN is unique in two ways. First its lifetime in the TTL is on the order of the upper limit of the residence time of the TTL, and can survive a zonal trip around the globe. The value of PAN measured in the upper troposphere and lower stratosphere therefore contains a statistical distribution from zonal sources, sinks and convection, from within this month timescale. A second difference is that unlike most VSLS species, the source region for PAN extends above the trapped bounder layer. PAN measurements in the UT and TTL are therefore sensitive to convective inflow above the boundary layer in the lower troposphere, as is also the case for water isotope measurements. Most convective processes are highly turbulent with substantial entrainment expected. The dominant convective mass flux into the TTL may not come from the trapped boundary layer where most VSLS are prevalent.

  6. Convective Transport of Very-short-lived Bromocarbons to the Stratosphere

    NASA Technical Reports Server (NTRS)

    Liang, Qing; Atlas, Elliot Leonard; Blake, Donald Ray; Dorf, Marcel; Pfeilsticker, Klaus August; Schauffler, Sue Myhre

    2014-01-01

    We use the NASA GEOS Chemistry Climate Model (GEOSCCM) to quantify the contribution of two most important brominated very short-lived substances (VSLS), bromoform (CHBr3) and dibromomethane (CH2Br2), to stratospheric bromine and its sensitivity to convection strength. Model simulations suggest that the most active transport of VSLS from the marine boundary layer through the tropopause occurs over the tropical Indian Ocean, the Western Pacific warm pool, and off the Pacific coast of Mexico. Together, convective lofting of CHBr3 and CH2Br2 and their degradation products supplies 8 ppt total bromine to the base of the Tropical Tropopause Layer (TTL, 150 hPa), similar to the amount of VSLS organic bromine available in the marine boundary layer (7.8-8.4 ppt) in the above active convective lofting regions. Of the total 8 ppt VSLS-originated bromine that enters the base of TTL at 150 hPa, half is in the form of source gas injection (SGI) and half as product gas injection (PGI). Only a small portion (< 10%) the VSLS-originated bromine is removed via wet scavenging in the TTL before reaching the lower stratosphere. On global and annual average, CHBr3 and CH2Br2, together, contribute 7.7 pptv to the present-day inorganic bromine in the stratosphere. However, varying model deep convection strength between maximum and minimum convection conditions can introduce a 2.6 pptv uncertainty in the contribution of VSLS to inorganic bromine in the stratosphere (BryVSLS). Contrary to the conventional wisdom, minimum convection condition leads to a larger BryVSLS as the reduced scavenging in soluble product gases, thus a significant increase in PGI (2-3 ppt), greatly exceeds the relative minor decrease in SGI (a few 10ths ppt.

  7. Polyhalogenated Very Short Live Substances in the Atlantic Ocean, and their Linkages with Ocean Primary Production

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Yvon-Lewis, S. A.; Hu, L.; Bianchi, T. S.; Campbell, L.; Smith, R. W.

    2011-12-01

    The Halocarbon Air-Sea Transect - Atlantic (HalocAST-A) cruise was conducted aboard FS Polarstern during the ANT-XXVII/1 expedition. The ship departed from Bremerhaven, Germany on October 25th and arrived in Cape Town, South Africa on November 24th in 2010. The HalocAST-A cruise was devoted to studying air-sea fluxes of a suite of halocarbon compounds. Atmospheric mixing ratios and seawater concentrations of the halocarbons were continuously measured with the gas chromatograph - mass spectrometer (GC-MS). This study focuses on the polyhalogenated very short lived substances (VSLSs) such as bromoform (CHBr3), dibromomethane (CH2Br2), chlorodibromomethane (CHClBr2), and bromodichloromethane (CHBrCl2). The goal of this study is to examine the distributions of these compounds and possible relationship between their emissions and oceanic primary production. Therefore, along with the halocarbon concentrations, parameters like dissolved organic carbon concentrations, nutrient concentrations, pigment concentrations, and picoplankton and heterotrophic bacteria counts were also determined. The observed saturation anomalies indicated these VSLSs were supersaturated for almost the entire duration of the cruise. The highest seawater concentrations for these compounds were observed near the Canary Islands. Air mixing ratios were also elevated in this region. The net fluxes for CHBr3, CH2Br2, CHClBr2, and CHBrCl2 were 13.8 nmol m-2 d-1, 4.5 nmol m-2 d-1, 4.5 nmol m-2 d-1 and 1.2 nmol m-2 d-1, respectively. During the HalocAST-A cruise, these compounds exhibit similar trends with total chlorophyll a. Contributions from selected phytoplankton group will be further assessed through the use of individual pigment biomarkers.

  8. Climate responses to anthropogenic emissions of short-lived climate pollutants

    NASA Astrophysics Data System (ADS)

    Baker, L. H.; Collins, W. J.; Olivié, D. J. L.; Cherian, R.; Hodnebrog, Ø.; Myhre, G.; Quaas, J.

    2015-07-01

    Policies to control air quality focus on mitigating emissions of aerosols and their precursors, and other short-lived climate pollutants (SLCPs). On a local scale, these policies will have beneficial impacts on health and crop yields, by reducing particulate matter (PM) and surface ozone concentrations; however, the climate impacts of reducing emissions of SLCPs are less straightforward to predict. In this paper we consider a set of idealized, extreme mitigation strategies, in which the total anthropogenic emissions of individual SLCP emissions species are removed. This provides an upper bound on the potential climate impacts of such air quality strategies. We focus on evaluating the climate responses to changes in anthropogenic emissions of aerosol precursor species: black carbon (BC), organic carbon (OC) and sulphur dioxide (SO2). We perform climate integrations with four fully coupled atmosphere-ocean global climate models (AOGCMs), and examine the effects on global and regional climate of removing the total land-based anthropogenic emissions of each of the three aerosol precursor species. We find that the SO2 emissions reductions lead to the strongest response, with all models showing an increase in surface temperature focussed in the Northern Hemisphere mid and (especially) high latitudes, and showing a corresponding increase in global mean precipitation. Changes in precipitation patterns are driven mostly by a northward shift in the ITCZ (Intertropical Convergence Zone), consistent with the hemispherically asymmetric warming pattern driven by the emissions changes. The BC and OC emissions reductions give a much weaker response, and there is some disagreement between models in the sign of the climate responses to these perturbations. These differences between models are due largely to natural variability in sea-ice extent, circulation patterns and cloud changes. This large natural variability component to the signal when the ocean circulation and sea-ice are free-running means that the BC and OC mitigation measures do not necessarily lead to a discernible climate response.

  9. Climate responses to anthropogenic emissions of short-lived climate pollutants

    NASA Astrophysics Data System (ADS)

    Baker, L. H.; Collins, W. J.; Olivié, D. J. L.; Cherian, R.; Hodnebrog, Ø.; Myhre, G.; Quaas, J.; Samset, B. H.

    2015-02-01

    Policies to control air quality focus on mitigating emissions of aerosols and their precursors, and other short-lived climate pollutants (SLCPs). On a local scale, these policies will have beneficial impacts on health and crop yields, by reducing particulate matter (PM) and surface ozone concentrations; however, the climate impacts of reducing emissions of SLCPs are less straightforward to predict. In this paper we consider a set of idealised, extreme mitigation strategies, in which the total anthropogenic emissions of individual SLCP emissions species are removed. This provides an upper bound on the potential climate impacts of such air quality strategies. We focus on evaluating the climate responses to changes in anthropogenic emissions of aerosol precursor species: black carbon (BC), organic carbon (OC) and sulphur dioxide (SO2). We perform climate integrations with four fully coupled atmosphere-ocean global climate models (AOGCMs), and examine the effects on global and regional climate of removing the total land-based anthropogenic emissions of each of the three aerosol precursor species. We find that the SO2 emissions reductions lead to the strongest response, with all three models showing an increase in surface temperature focussed in the northern hemisphere high latitudes, and a corresponding increase in global mean precipitation and run-off. Changes in precipitation and run-off patterns are driven mostly by a northward shift in the ITCZ, consistent with the hemispherically asymmetric warming pattern driven by the emissions changes. The BC and OC emissions reductions give a much weaker forcing signal, and there is some disagreement between models in the sign of the climate responses to these perturbations. These differences between models are due largely to natural variability in sea-ice extent, circulation patterns and cloud changes. This large natural variability component to the signal when the ocean circulation and sea-ice are free-running means that the BC and OC mitigation measures do not necessarily lead to a discernible climate response.

  10. In vitro immunotoxic and genotoxic activities of particles emitted from two different small-scale wood combustion appliances

    NASA Astrophysics Data System (ADS)

    Tapanainen, Maija; Jalava, Pasi I.; Mäki-Paakkanen, Jorma; Hakulinen, Pasi; Happo, Mikko S.; Lamberg, Heikki; Ruusunen, Jarno; Tissari, Jarkko; Nuutinen, Kati; Yli-Pirilä, Pasi; Hillamo, Risto; Salonen, Raimo O.; Jokiniemi, Jorma; Hirvonen, Maija-Riitta

    2011-12-01

    Residential wood combustion appliances emit large quantities of fine particles which are suspected to cause a substantial health burden worldwide. Wood combustion particles contain several potential health-damaging metals and carbon compounds such as polycyclic aromatic hydrocarbons (PAH), which may determine the toxic properties of the emitted particles. The aim of the present study was to characterize in vitro immunotoxicological and chemical properties of PM 1 ( Dp ≤ 1 μm) emitted from a pellet boiler and a conventional masonry heater. Mouse RAW264.7 macrophages were exposed for 24 h to different doses of the emission particles. Cytotoxicity, production of the proinflammatory cytokine TNF-α and the chemokine MIP-2, apoptosis and phases of the cell cycle as well as genotoxic activity were measured after the exposure. The type of wood combustion appliance had a significant effect on emissions and chemical composition of the particles. All the studied PM 1 samples induced cytotoxic, genotoxic and inflammatory responses in a dose-dependent manner. The particles emitted from the conventional masonry heater were 3-fold more potent inducers of programmed cell death and DNA damage than those emitted from the pellet boiler. Furthermore, the particulate samples that induced extensive DNA damage contained also large amounts of PAH compounds. Instead, significant differences between the studied appliances were not detected in measurements of inflammatory mediators, although the chemical composition of the combustion particles differed considerably from each other. In conclusion, the present results show that appliances representing different combustion technology have remarkable effects on physicochemical and associated toxicological and properties of wood combustion particles. The present data indicate that the particles emitted from incomplete combustion are toxicologically more potent than those emitted from more complete combustion processes.

  11. IN-SITU RADIONUCLIDE TRANSPORT NEAR THE NOPAL I URANIUM DEPOSIT AT PENA BLANCA, MEXICO: CONSTRAINTS FROM SHORT-LIVED DECAY-SERIES RADIONUCLIDES

    SciTech Connect

    S. Luo; T.L. Ku; V. Todd; M. Murrell; J. Alfredo Rodriguez Pineda; J. Dinsmoor; A. Mitchell

    2005-07-11

    For nuclear waste management, an important mechanism by which radioactive waste components are isolated from returning to the human environment, the biosphere, is by the geological barrier in which the effectiveness of the barrier is characterized by in-situ retardation factor, i.e., the transport rate of a radionuclide relative to that of groundwater. As part of natural analog studies of the Yucca Mountain Project of the U. S. Department of Energy, we propose such characterization by using naturally-occurring decay-series radioisotopes as an analog. We collected large-volume (>1000 liters) groundwater samples from three wells (PB, Pozos, and PB4, respectively) near the Nopal I Uranium Ore site at Pena Blanca, Mexico, by using an in-situ Mn-cartridge filtration technique for analysis of short-lived decay-series radionuclides. Results show that the activities of short-lived radioisotopes ({sup 228}Ra, {sup 224}Ra and {sup 223}Ra) and activity ratios of {sup 224}Ra/{sup 228}Ra and {sup 224}Ra/{sup 223}Ra are higher at PB and Pozos than at PB4. In contrast, the {sup 210}Po activity is much lower at PB and Pozos than at PB4. The high Ra activities and activities ratios at PB and Pozos are attributable to the high alpha-recoil input from the aquifer rocks, while the high {sup 210}Po activity at PB4 is due to the enhanced colloidal transport. Based on a uranium-series transport model, we estimate that the in-situ retardation factor of Ra is (0.43 {+-} 0.02) x 10{sup 3} at PB, (1.68 {+-} 0.08) x 10{sup 3} at Pozos, and (1.19 {+-} 0.08) x 10{sup 3} at PB4 and that the mean fracture width in the aquifer rocks is about 0.23 {micro}m at PB, 0.37 {micro}m at Posos, and 4.0 {micro}m at PB4, respectively. The large fracture width at PB4 as derived from the model provides an additional evidence to the inference from the Po measurements that particle-reactive radionuclides are transported mainly as colloidal forms through the large fractures in rocks. Our model also suggests that in addition to alpha recoil, decay of {sup 226}Ra from the adsorbed phases also contributes a significant source of {sup 222}Rn to groundwater. It appears that the information obtained from this study provides useful testing and validation for the Yucca Mountain total system performance assessment model (TSPA).

  12. Distributions of short-lived radioactive nuclei produced by young embedded star clusters

    SciTech Connect

    Adams, Fred C.; Fatuzzo, Marco; Holden, Lisa

    2014-07-01

    Most star formation in the Galaxy takes place in clusters, where the most massive members can affect the properties of other constituent solar systems. This paper considers how clusters influence star formation and forming planetary systems through nuclear enrichment from supernova explosions, where massive stars deliver short-lived radioactive nuclei (SLRs) to their local environment. The decay of these nuclei leads to both heating and ionization, and thereby affects disk evolution, disk chemistry, and the accompanying process of planet formation. Nuclear enrichment can take place on two spatial scales: (1) within the cluster itself (ℓ ∼ 1 pc), the SLRs are delivered to the circumstellar disks associated with other cluster members. (2) On the next larger scale (ℓ ∼ 2-10 pc), SLRs are injected into the background molecular cloud; these nuclei provide heating and ionization to nearby star-forming regions and to the next generation of disks. For the first scenario, we construct the expected distributions of radioactive enrichment levels provided by embedded clusters. Clusters can account for the SLR mass fractions inferred for the early Solar Nebula, but typical SLR abundances are lower by a factor of ∼10. For the second scenario, we find that distributed enrichment of SLRs in molecular clouds leads to comparable abundances. For both the direct and distributed enrichment processes, the masses of {sup 26}Al and {sup 60}Fe delivered to individual circumstellar disks typically fall in the range 10-100 pM {sub ☉} (where 1 pM {sub ☉} = 10{sup –12} M {sub ☉}). The corresponding ionization rate due to SLRs typically falls in the range ζ{sub SLR} ∼ 1-5 × 10{sup –19} s{sup –1}. This ionization rate is smaller than that due to cosmic rays, ζ{sub CR} ∼ 10{sup –17} s{sup –1}, but will be important in regions where cosmic rays are attenuated (e.g., disk mid-planes).

  13. Transport and Chemistry of Short-Lived Bromocarbons in the Tropics

    NASA Astrophysics Data System (ADS)

    Hossaini, Ryan; Chipperfield, Martyn; Monge-Sanz, Beatriz; Richards, Nigel; Atlas, Elliot; Blake, Donald

    2010-05-01

    We have developed a detailed chemical scheme for the degradation of the short-lived source gases bromoform (CHBr3) and dibromomethane (CH2Br2) and implemented it in the TOMCAT/SLIMCAT three-dimensional (3D) chemical transport model (CTM). The CTM has been used to predict the distribution of the two source gases (SGs) and 11 of their organic product gases (PGs). These first global calculations of the organic PGs show that their abundance is small. The longest lived organic PGs are CBr2O and CHBrO, but their peak tropospheric abundance relative to the surface volume mixing ratio (vmr) of the SGs is less than 5%. We calculate their mean local tropospheric lifetimes in the tropics to be ~7 and ~2 days (due to photolysis), respectively. Therefore, the assumption in previous modelling studies that SG degradation leads immediately to inorganic bromine seems reasonable. We have compared observed tropical SG profiles from a number of aircraft campaigns with various model experiments. In the tropical tropopause layer (TTL) we find that the CTM run using p levels (TOMCAT) and vertical winds from analysed divergence overestimates the abundance of CH2Br2, and to a lesser extent CHBr3, although the data is sparse and comparisons are not conclusive. Better agreement in the TTL is obtained in the sensitivity run using ? levels (SLIMCAT) and vertical motion from diabatic heating rates. Trajectory estimates of residence times in the two model versions show slower vertical transport in the SLIMCAT ?-level version. In the p-level model even when we switch off convection we still find significant amounts of the SGs considered may reach the cold point tropopause; the stratospheric source gas injection (SGI) is only reduced by ~16% for CHBr3 and ~2% for CH2Br2 without convection. Overall, the relative importance of the SG pathway and the PG pathway for transport of bromine to the stratospheric overworld (?>380 K) has been assessed. Assuming a 10-day washout lifetime of Bry in TOMCAT, we find the delivery of total Br from CHBr3 to be 0.72 pptv with ~53% of this coming from SGI. Similary, for CH2Br2 we find a total Br value of 1.69 pptv with ~94% coming from SGI. We infer that these species contribute ~2.4 pptv of inorganic bromine to the lower stratosphere with SGI being the dominant pathway. Slower transport to and through the TTL would decrease this estimate.

  14. Multimodel emission metrics for regional emissions of short lived climate forcers

    NASA Astrophysics Data System (ADS)

    Aamaas, B.; Berntsen, T. K.; Fuglestvedt, J. S.; Shine, K. P.; Bellouin, N.

    2015-09-01

    For short lived climate forcers (SLCFs), the impact of emissions depends on where and when the emissions take place. Comprehensive new calculations of various emission metrics for SLCFs are presented based on radiative forcing (RF) values calculated in four different (chemistry-transport or coupled-chemistry climate) models. We distinguish between emissions during summer (May-October) and winter season (November-April) for emissions from Europe, East Asia, as well as the global shipping sector. The species included in this study are aerosols and aerosols precursors (BC, OC, SO2, NH3), and ozone precursors (NOx, CO, VOC), which also influence aerosols, to a lesser degree. Emission metrics for global climate responses of these emissions, as well as for CH4, have been calculated relative to CO2, using Global Warming Potential (GWP) and Global Temperature change Potential (GTP), based on dedicated RF simulations by four global models. The emission metrics include indirect cloud effects of aerosols and the semi-direct forcing for BC. In addition to the standard emission metrics for pulse and sustained emissions, we have also calculated a new emission metric designed for an emission profile consisting of a ramp up period of 15 years followed by sustained emissions, which is more appropriate for a gradual implementation of mitigation policies. For the aerosols, the emission metric values are larger in magnitude for Europe than East Asia and for summer than winter. A variation is also observed for the ozone precursors, with largest values in East Asia and winter for CO and in Europe and summer for VOC. In general, the variations between the emission metrics derived from different models are larger than the variations between regions and seasons, but the regional and seasonal variations for the best estimate also hold for most of the models individually. Further, the estimated climate impact of a mitigation policy package is robust even when accounting for correlations. For the ramp up emission metrics, the values are generally larger than for pulse or sustained emissions, which holds for all SLCFs. For a potential SLCFs mitigation policy, the dependency of metric values on the region and season of emission should be considered.

  15. Seasonal variation in the behaviour of a short-lived rodent

    PubMed Central

    2013-01-01

    Background Short lived, iteroparous animals in seasonal environments experience variable social and environmental conditions over their lifetime. Animals can be divided into those with a “young-of-the-year” life history (YY, reproducing and dying in the summer of birth) and an “overwinter” life history (OW, overwintering in a subadult state before reproducing next spring). We investigated how behavioural patterns across the population were affected by season and sex, and whether variation in behaviour reflects the variation in life history patterns of each season. Applications of pace-of-life (POL) theory would suggest that long-lived OW animals are shyer in order to increase survival, and YY are bolder in order to increase reproduction. Therefore, we expected that in winter and spring samples, when only OW can be sampled, the animals should be shyer than in summer and autumn, when both OW and YY animals can be sampled. We studied common vole (Microtus arvalis) populations, which express typical, intra-annual density fluctuation. We captured a total of 492 voles at different months over 3 years and examined boldness and activity level with two standardised behavioural experiments. Results Behavioural variables of the two tests were correlated with each other. Boldness, measured as short latencies in both tests, was extremely high in spring compared to other seasons. Activity level was highest in spring and summer, and higher in males than in females. Conclusion Being bold in laboratory tests may translate into higher risk-taking in nature by being more mobile while seeking out partners or valuable territories. Possible explanations include asset-protection, with OW animals being rather old with low residual reproductive value in spring. Therefore, OW may take higher risks during this season. Offspring born in spring encounter a lower population density and may have higher reproductive value than offspring of later cohorts. A constant connection between life history and animal personality, as suggested by the POL theory, however, was not found. Nevertheless, correlations of traits suggest the existence of animal personalities. In conclusion, complex patterns of population dynamics, seasonal variation in life histories, and variability of behaviour due to asset-protection may cause complex seasonal behavioural dynamics in a population. PMID:24238069

  16. Evaluating the climate and air quality impacts of short-lived pollutants

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Aamaas, B.; Amann, M.; Baker, L. H.; Bellouin, N.; Berntsen, T. K.; Boucher, O.; Cherian, R.; Collins, W.; Daskalakis, N.; Dusinska, M.; Eckhardt, S.; Fuglestvedt, J. S.; Harju, M.; Heyes, C.; Hodnebrog, Ø.; Hao, J.; Im, U.; Kanakidou, M.; Klimont, Z.; Kupiainen, K.; Law, K. S.; Lund, M. T.; Maas, R.; MacIntosh, C. R.; Myhre, G.; Myriokefalitakis, S.; Olivié, D.; Quaas, J.; Quennehen, B.; Raut, J.-C.; Rumbold, S. T.; Samset, B. H.; Schulz, M.; Seland, Ø.; Shine, K. P.; Skeie, R. B.; Wang, S.; Yttri, K. E.; Zhu, T.

    2015-09-01

    This paper presents a summary of the work done within the European Union's Seventh Framework Programme project ECLIPSE (Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants). ECLIPSE had a unique systematic concept for designing a realistic and effective mitigation scenario for short-lived climate pollutants (SLCPs; methane, aerosols and ozone, and their precursor species) and quantifying its climate and air quality impacts, and this paper presents the results in the context of this overarching strategy. The first step in ECLIPSE was to create a new emission inventory based on current legislation (CLE) for the recent past and until 2050. Substantial progress compared to previous work was made by including previously unaccounted types of sources such as flaring of gas associated with oil production, and wick lamps. These emission data were used for present-day reference simulations with four advanced Earth system models (ESMs) and six chemistry transport models (CTMs). The model simulations were compared with a variety of ground-based and satellite observational data sets from Asia, Europe and the Arctic. It was found that the models still underestimate the measured seasonality of aerosols in the Arctic but to a lesser extent than in previous studies. Problems likely related to the emissions were identified for northern Russia and India, in particular. To estimate the climate impacts of SLCPs, ECLIPSE followed two paths of research: the first path calculated radiative forcing (RF) values for a large matrix of SLCP species emissions, for different seasons and regions independently. Based on these RF calculations, the Global Temperature change Potential metric for a time horizon of 20 years (GTP20) was calculated for each SLCP emission type. This climate metric was then used in an integrated assessment model to identify all emission mitigation measures with a beneficial air quality and short-term (20-year) climate impact. These measures together defined a SLCP mitigation (MIT) scenario. Compared to CLE, the MIT scenario would reduce global methane (CH4) and black carbon (BC) emissions by about 50 and 80 %, respectively. For CH4, measures on shale gas production, waste management and coal mines were most important. For non-CH4 SLCPs, elimination of high-emitting vehicles and wick lamps, as well as reducing emissions from gas flaring, coal and biomass stoves, agricultural waste, solvents and diesel engines were most important. These measures lead to large reductions in calculated surface concentrations of ozone and particulate matter. We estimate that in the EU, the loss of statistical life expectancy due to air pollution was 7.5 months in 2010, which will be reduced to 5.2 months by 2030 in the CLE scenario. The MIT scenario would reduce this value by another 0.9 to 4.3 months. Substantially larger reductions due to the mitigation are found for China (1.8 months) and India (11-12 months). The climate metrics cannot fully quantify the climate response. Therefore, a second research path was taken. Transient climate ensemble simulations with the four ESMs were run for the CLE and MIT scenarios, to determine the climate impacts of the mitigation. In these simulations, the CLE scenario resulted in a surface temperature increase of 0.70 ± 0.14 K between the years 2006 and 2050. For the decade 2041-2050, the warming was reduced by 0.22 ± 0.07 K in the MIT scenario, and this result was in almost exact agreement with the response calculated based on the emission metrics (reduced warming of 0.22 ± 0.09 K). The metrics calculations suggest that non-CH4 SLCPs contribute ~ 22 % to this response and CH4 78 %. This could not be fully confirmed by the transient simulations, which attributed about 90 % of the temperature response to CH4 reductions. Attribution of the observed temperature response to non-CH4 SLCP emission reductions and BC specifically is hampered in the transient simulations by small forcing and co-emitted species of the emission basket chosen. Nevertheless, an important conclusion is that our mitigation basket as a whole would lead to clear benefits for both air quality and climate. The climate response from BC reductions in our study is smaller than reported previously, possibly because our study is one of the first to use fully coupled climate models, where unforced variability and sea ice responses cause relatively strong temperature fluctuations that may counteract (and, thus, mask) the impacts of small emission reductions. The temperature responses to the mitigation were generally stronger over the continents than over the oceans, and with a warming reduction of 0.44 K (0.39-0.49) K the largest over the Arctic. Our calculations suggest particularly beneficial climate responses in southern Europe, where surface warming was reduced by about 0.3 K and precipitation rates were increased by about 15 (6-21) mm yr-1 (more than 4 % of total precipitation) from spring to autumn. Thus, the mitigation could help to alleviate expected future drought and water shortages in the Mediterranean area. We also report other important results of the ECLIPSE project.

  17. Evaluating the climate and air quality impacts of short-lived pollutants

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Aamaas, B.; Amann, M.; Baker, L. H.; Bellouin, N.; Berntsen, T. K.; Boucher, O.; Cherian, R.; Collins, W.; Daskalakis, N.; Dusinska, M.; Eckhardt, S.; Fuglestvedt, J. S.; Harju, M.; Heyes, C.; Hodnebrog, Ø.; Hao, J.; Im, U.; Kanakidou, M.; Klimont, Z.; Kupiainen, K.; Law, K. S.; Lund, M. T.; Maas, R.; MacIntosh, C. R.; Myhre, G.; Myriokefalitakis, S.; Olivié, D.; Quaas, J.; Quennehen, B.; Raut, J.-C.; Rumbold, S. T.; Samset, B. H.; Schulz, M.; Seland, Ø.; Shine, K. P.; Skeie, R. B.; Wang, S.; Yttri, K. E.; Zhu, T.

    2015-06-01

    This paper presents a summary of the work done within the European Union's Seventh Framework Programme project ECLIPSE (Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants). ECLIPSE had a unique systematic concept for designing a realistic and effective mitigation scenario for short-lived climate pollutants (SLCPs: methane, aerosols and ozone, and their precursor species) and quantifying its climate and air quality impacts, and this paper presents the results in the context of this overarching strategy. The first step in ECLIPSE was to create a new emission inventory based on current legislation (CLE) for the recent past and until 2050. Substantial progress compared to previous work was made by including previously unaccounted types of sources such as flaring of gas associated with oil production, and wick lamps. These emission data were used for present-day reference simulations with four advanced Earth system models (ESMs) and six chemistry transport models (CTMs). The model simulations were compared with a variety of ground-based and satellite observational data sets from Asia, Europe and the Arctic. It was found that the models still underestimate the measured seasonality of aerosols in the Arctic but to a lesser extent than in previous studies. Problems likely related to the emissions were identified for Northern Russia and India, in particular. To estimate the climate impacts of SLCPs, ECLIPSE followed two paths of research: the first path calculated radiative forcing (RF) values for a large matrix of SLCP species emissions, for different seasons and regions independently. Based on these RF calculations, the Global Temperature change Potential metric for a time horizon of 20 years (GTP20) was calculated for each SLCP emission type. This climate metric was then used in an integrated assessment model to identify all emission mitigation measures with a beneficial air quality and short-term (20 year) climate impact. These measures together defined a SLCP mitigation (MIT) scenario. Compared to CLE, the MIT scenario would reduce global methane (CH4) and black carbon emissions by about 50 and 80%, respectively. For CH4, measures on shale gas production, waste management and coal mines were most important. For non-CH4 SLCPs, elimination of high emitting vehicles and wick lamps, as well as reducing emissions from gas flaring, coal and biomass stoves, agricultural waste, solvents and diesel engines were most important. These measures lead to large reductions in calculated surface concentrations of ozone and particulate matter. We estimate that in the EU the loss of statistical life expectancy due to air pollution was 7.5 months in 2010, which will be reduced to 5.2 months by 2030 in the CLE scenario. The MIT scenario would reduce this value by another 0.9 to 4.3 months. Substantially larger reductions due to the mitigation are found for China (1.8 months) and India (11-12 months). The climate metrics cannot fully quantify the climate response. Therefore, a second research path was taken. Transient climate ensemble simulations with these ESMs were run for the CLE and MIT scenarios, to determine the climate impacts of the mitigation. In these simulations, the CLE scenario resulted in a surface temperature increase of 0.70±0.14 K between the years 2006 and 2050. For the decade 2041-2050, the warming was reduced by 0.22±0.07 K in the MIT scenario, and this result was in almost exact agreement with the response calculated based on the emission metrics (reduced warming of 0.22±0.09 K). The metrics calculations suggest that non-CH4 SLCPs contribute ∼22% to this response and CH4 78%. This could not be fully confirmed by the transient simulations, which attributed about 90% of the temperature response to CH4 reductions. Attribution of the observed temperature response to non-CH4 SLCP emission reductions and black carbon (BC) specifically is hampered in the transient simulations by small forcing and co-emitted species of the emission basket chosen. Nevertheless, an important conclusion is that our mitigation basket as a whole would lead to clear benefits for both air quality and climate. The climate response from BC reductions in our study is smaller than reported previously, largely because our study is one of the first to use fully coupled climate models, where unforced variability and sea-ice responses may counteract the impacts of small emission reductions. The temperature responses to the mitigation were generally stronger over the continents than over the oceans, and with a warming reduction of 0.44 K (0.39-0.49) largest over the Arctic. Our calculations suggest particularly beneficial climate responses in Southern Europe, where the surface warming was reduced by about 0.3 K and precipitation rates were increased by about 15 (6-21) mm yr-1 (more than 4% of total precipitation) from spring to autumn. Thus, the mitigation could help to alleviate expected future drought and water shortages in the Mediterranean area. We also report other important results of the ECLIPSE project.

  18. First Use of High Charge States for Mass Measurements of Short-Lived Nuclides in a Penning Trap

    SciTech Connect

    Ettenauer, S.; Gallant, A. T.; Dilling, J.; Simon, M. C.; Chaudhuri, A.; Mane, E.; Delheij, P.; Pearson, M. R.; Brunner, T.; Chowdhury, U.; Simon, V. V.; Brodeur, M.; Andreoiu, C.; Audi, G.; Lopez-Urrutia, J. R. Crespo; Ullrich, J.; Gwinner, G.; Lapierre, A.; Lunney, D.; Ringle, R.

    2011-12-30

    Penning trap mass measurements of short-lived nuclides have been performed for the first time with highly charged ions, using the TITAN facility at TRIUMF. Compared to singly charged ions, this provides an improvement in experimental precision that scales with the charge state q. Neutron-deficient Rb isotopes have been charge bred in an electron beam ion trap to q=8-12+ prior to injection into the Penning trap. In combination with the Ramsey excitation scheme, this unique setup creating low energy, highly charged ions at a radioactive beam facility opens the door to unrivaled precision with gains of 1-2 orders of magnitude. The method is particularly suited for short-lived nuclides such as the superallowed {beta} emitter {sup 74}Rb (T{sub 1/2}=65 ms). The determination of its atomic mass and an improved Q{sub EC} value are presented.

  19. PANTHER Data from SOLVE-II Through CR-AVE: A Contrast Between Long and Short Lived Compounds.

    NASA Astrophysics Data System (ADS)

    Moore, F. L.; Dutton, G. S.; Elkins, J. W.; Hall, B. D.; Hurst, D. F.; Nance, J. D.; Thompson, T. M.

    2006-12-01

    PANTHER (PAN and other Trace Hydrohalocarbons ExpeRiment) is an airborne 6-channel gas chromatograph that measures approximately 20 important atmospheric trace gases whose changing burdens impact air quality, climate change and both stratospheric and tropospheric ozone. In this presentation we will contrast measurements of the long-lived compounds against the short-lived compounds. The long-lived compounds tend to have well-defined troposphere boundary conditions and develop spatial gradients due to stratospheric processing. These measurements have played a major role in quantifying stratospheric transport, stratosphere- troposphere exchange, and ozone loss. In contrast the short-lived species develop spatial and temporal gradients in the tropical tropopause layer (TTL), due to variations in the surface boundary layer concentrations and the coupling of this surface boundary layer to the TTL via convective processes. Deep convection acts like a "conveyor belt" between the source region in the boundary layer and the relatively stable TTL region, often bypassing the free troposphere where scavenging of these short lived species takes place. Loss rates due to reaction with OH and thermal decomposition are reduced in the cold, dry air of the TTL, resulting in longer survival times. Isolation of the TTL region from the free troposphere can last from days to over a month. Significant amounts of these short-lived compound and their byproducts can therefore be transported into the lower stratosphere (LS). Of particular interest are compounds that contain bromine, iodine, and sulfur, not only because of their intrinsic harmful effects in the atmosphere, but also because they have unique source and sink regions that can help to de- convolve transport.

  20. Short-lived chlorine-36 in a Ca- and Al-rich inclusion from the Ningqiang carbonaceous chondrite.

    PubMed

    Lin, Yangting; Guan, Yunbin; Leshin, Laurie A; Ouyang, Ziyuan; Wang, Daode

    2005-02-01

    Excesses of sulfur-36 in sodalite, a chlorine-rich mineral, in a calcium- and aluminum-rich inclusion from the Ningqiang carbonaceous chondrite linearly correlate with chorine/sulfur ratios, providing direct evidence for the presence of short-lived chlorine-36 (with a half-life of 0.3 million years) in the early solar system. The best inferred (36Cl/35Cl)o ratios of the sodalite are approximately 5 x 10(-6). Different from other short-lived radionuclides, chlorine-36 was introduced into the inclusion by solid-gas reaction during secondary alteration. The alteration reaction probably took place at least 1.5 million years after the first formation of the inclusion, based on the correlated study of the 26Al-26Mg systems of the relict primary minerals and the alteration assemblages, from which we inferred an initial ratio of (36Cl/35Cl)o > or = 1.6 x 10(-4) at the time when calcium- and aluminum-rich inclusions formed. This discovery supports a supernova origin of short-lived nuclides [Cameron, A. G. W., Hoeflich, P., Myers, P. C. & Clayton, D. D. (1995) Astrophys. J. 447, L53; Wasserburg, G. J., Gallino, R. & Busso, M. (1998) Astrophys. J. 500, L189-L193], but presents a serious challenge for local irradiation models [Shu, F. H., Shang, H., Glassgold, A. E. & Lee, T. (1997) Science 277, 1475-1479; Gounelle, M., Shu, F. H., Shang, H., Glassgold, A. E., Rehm, K. E. & Lee, T. (2001) Astrophys. J. 548, 1051-1070]. Furthermore, the short-lived 36Cl may serve as a unique fine-scale chronometer for volatile-rock interaction in the early solar system because of its close association with aqueous and/or anhydrous alteration processes. PMID:15671168

  1. Short-lived chlorine-36 in a Ca- and Al-rich inclusion from the Ningqiang carbonaceous chondrite

    PubMed Central

    Lin, Yangting; Guan, Yunbin; Leshin, Laurie A.; Ouyang, Ziyuan; Wang, Daode

    2005-01-01

    Excesses of sulfur-36 in sodalite, a chlorine-rich mineral, in a calcium- and aluminum-rich inclusion from the Ningqiang carbonaceous chondrite linearly correlate with chorine/sulfur ratios, providing direct evidence for the presence of short-lived chlorine-36 (with a half-life of 0.3 million years) in the early solar system. The best inferred (36Cl/35Cl)o ratios of the sodalite are ≈5 × 10-6. Different from other short-lived radionuclides, chlorine-36 was introduced into the inclusion by solid-gas reaction during secondary alteration. The alteration reaction probably took place at least 1.5 million years after the first formation of the inclusion, based on the correlated study of the 26Al-26Mg systems of the relict primary minerals and the alteration assemblages, from which we inferred an initial ratio of (36Cl/35Cl)o > 1.6 × 10-4 at the time when calcium- and aluminum-rich inclusions formed. This discovery supports a supernova origin of short-lived nuclides [Cameron, A. G. W., Hoeflich, P., Myers, P. C. & Clayton, D. D. (1995) Astrophys. J. 447, L53; Wasserburg, G. J., Gallino, R. & Busso, M. (1998) Astrophys. J. 500, L189–L193], but presents a serious challenge for local irradiation models [Shu, F. H., Shang, H., Glassgold, A. E. & Lee, T. (1997) Science 277, 1475–1479; Gounelle, M., Shu, F. H., Shang, H., Glassgold, A. E., Rehm, K. E. & Lee, T. (2001) Astrophys. J. 548, 1051–1070]. Furthermore, the short-lived 36Cl may serve as a unique fine-scale chronometer for volatile-rock interaction in the early solar system because of its close association with aqueous and/or anhydrous alteration processes. PMID:15671168

  2. SU-C-204-07: The Production of Short-Lived Positron Emitters in Proton Therapy

    SciTech Connect

    Buitenhuis, H J T; Dendooven, P; Biegun, A K; Goethem, M-J van; Graaf, E R van der; Brandenburg, S; Diblen, F

    2015-06-15

    Purpose: To investigate the production and effect of short-lived positron emitters when using PET for in-vivo range verification during a proton therapy irradiation. Methods: The integrated production of short-lived positron emitters in the stopping of 55 MeV protons was measured in water, carbon, phosphorus and calcium targets. The experimental production rates are used to calculate the production on PMMA and a representative set of 4 tissue materials. The number of decays integrated over an irradiation in these materials is calculated as function of the duration of the irradiation, considering irradiations with the same total number of protons. Results: The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: 12-N (T1/2 = 11 ms) on carbon (9.5% of the 11-C production), 29-P (T1/2 = 4.1 s) on phosphorus (20% of the 30-P production) and 38m-K (T1/2 = 0.92 s) on calcium (113% of the 38g-K production). No short-lived nuclides are produced on water. The most noticeable Result is that for an irradiation in (carbon-rich) adipose tissue, 12-N will dominate the PET image up to an irradiation duration of 70 s. On bone tissue, 15-O dominates over 12-N after 7–15 s (depending on the carbon-to-oxygen ratio). Conclusions: The presence of 12-N needs to be considered in PET imaging during proton beam irradiations as, depending on tissue composition and PET scanning protocol, it may noticeably deteriorate image quality due to the large positron range blurring. The results presented warrant investigations into the energy-dependent production of 12-N, 29-P and 38m-K and their effect on PET imaging during proton irradiations.

  3. Resveratrol prolongs lifespan and retards the onset of age-related markers in a short-lived vertebrate.

    PubMed

    Valenzano, Dario R; Terzibasi, Eva; Genade, Tyrone; Cattaneo, Antonino; Domenici, Luciano; Cellerino, Alessandro

    2006-02-01

    Resveratrol, a natural phytoalexin found in grapes and red wine, increases longevity in the short-lived invertebrates Caenorhabditis elegans and Drosophila and exerts a variety of biological effects in vertebrates, including protection from ischemia and neurotoxicity. Its effects on vertebrate lifespan were not yet known. The relatively long lifespan of mice, which live at least 2.5 years, is a hurdle for life-long pharmacological trials. Here, the authors used the short-lived seasonal fish Nothobranchius furzeri with a maximum recorded lifespan of 13 weeks in captivity. Short lifespan in this species is not the result of spontaneous or targeted genetic mutations, but a natural trait correlated with the necessity to breed in an ephemeral habitat and tied with accelerated development and expression of ageing biomarkers at a cellular level. Resveratrol was added to the food starting in early adulthood and caused a dose-dependent increase of median and maximum lifespan. In addition, resveratrol delays the age-dependent decay of locomotor activity and cognitive performances and reduces the expression of neurofibrillary degeneration in the brain. These results demonstrate that food supplementation with resveratrol prolongs lifespan and retards the expression of age-dependent traits in a short-lived vertebrate. PMID:16461283

  4. Proline-rich tyrosine kinase-2 is critical for CD8 T-cell short-lived effector fate

    PubMed Central

    Beinke, Sören; Phee, Hyewon; Clingan, Jonathan M.; Schlessinger, Joseph; Matloubian, Mehrdad; Weiss, Arthur

    2010-01-01

    T-cell interactions with antigen-presenting cells are important for CD8 T-cell effector or memory fate determination. The integrin leukocyte function-associated antigen-1 (LFA-1) mediates T-cell adhesion but the contribution of LFA-1–induced signaling pathways to T-cell responses is poorly understood. Here we demonstrate that proline-rich tyrosine kinase-2 (PYK2) deficiency impairs CD8 T-cell activation by synergistic LFA-1 and T-cell receptor stimulation. Furthermore, PYK2 is essential for LFA-1-mediated CD8 T-cell adhesion and LFA-1 costimulation of CD8 T-cell migration. During lymphocytic choriomeningitis virus infection in vivo, PYK2 deficiency results in a specific loss of short-lived effector CD8 T cells but does not affect memory-precursor CD8 T-cell development. Similarly, lack of LFA-1 primarily impairs the generation of short-lived effector cells. Thus, PYK2 facilitates LFA-1–dependent CD8 T-cell responses and promotes CD8 T-cell short-lived effector fate, suggesting that PYK2 may be an interesting therapeutic target to suppress exacerbated CD8 T-cell responses. PMID:20805505

  5. Proline-rich tyrosine kinase-2 is critical for CD8 T-cell short-lived effector fate.

    PubMed

    Beinke, Sören; Phee, Hyewon; Clingan, Jonathan M; Schlessinger, Joseph; Matloubian, Mehrdad; Weiss, Arthur

    2010-09-14

    T-cell interactions with antigen-presenting cells are important for CD8 T-cell effector or memory fate determination. The integrin leukocyte function-associated antigen-1 (LFA-1) mediates T-cell adhesion but the contribution of LFA-1-induced signaling pathways to T-cell responses is poorly understood. Here we demonstrate that proline-rich tyrosine kinase-2 (PYK2) deficiency impairs CD8 T-cell activation by synergistic LFA-1 and T-cell receptor stimulation. Furthermore, PYK2 is essential for LFA-1-mediated CD8 T-cell adhesion and LFA-1 costimulation of CD8 T-cell migration. During lymphocytic choriomeningitis virus infection in vivo, PYK2 deficiency results in a specific loss of short-lived effector CD8 T cells but does not affect memory-precursor CD8 T-cell development. Similarly, lack of LFA-1 primarily impairs the generation of short-lived effector cells. Thus, PYK2 facilitates LFA-1-dependent CD8 T-cell responses and promotes CD8 T-cell short-lived effector fate, suggesting that PYK2 may be an interesting therapeutic target to suppress exacerbated CD8 T-cell responses. PMID:20805505

  6. Spatial and Time Coincidence Detection of the Decay Chain of Short-Lived Radioactive Nuclei

    SciTech Connect

    Granja, Carlos; Jakubek, Jan; Platkevic, Michal; Pospisil, Stanislav

    2010-08-04

    The quantum counting position sensitive pixel detector Timepix with per-pixel energy and time resolution enables to detect radioactive ions and register the consecutive decay chain by simultaneous position-and time-correlation. This spatial and timing coincidence technique in the same sensor is demonstrated by the registration of the decay chain {sup 8}He{yields}{sup {beta} 8}Li and {sup 8}Li{yields}{sup {beta}-} {sup 8}Be{yields}{alpha}+{alpha} and by the measurement of the {beta} decay half-lives. Radioactive ions, selectively obtained from the Lohengrin fission fragment spectrometer installed at the High Flux Reactor of the ILL Grenoble, are delivered to the Timepix silicon sensor where decays of the implanted ions and daughter nuclei are registered and visualized. We measure decay lifetimes in the range {>=}{mu}s with precision limited just by counting statistics.

  7. Global Modeling and Projection of Short-Lived Climate Pollutants in an Earth System Model

    NASA Astrophysics Data System (ADS)

    Sudo, K.; Takemura, T.; Klimont, Z.; Kurokawa, J.; Akimoto, H.

    2013-12-01

    In predicting and mitigating future global warming, short-lived climate pollutants (SLCPs) such as tropospheric ozone (O3), black carbon (BC), and other related components including CH4/VOCs and aerosols play crucial roles as well as long-lived species like CO2 or N2O. Several recent studies suggests that reduction of heating SLCPs (i.e., O3 and black carbon) together with CH4 can decrease and delay the expected future warming, and can be an alternative to CO2 mitigation (Shindell et al., 2012). However it should be noted that there are still large uncertainties in simulating SLCPs and their climate impacts. For instance, present global models generally have a severe tendency to underestimate BC especially in remote areas like the polar regions as shown by the recent model intercomparison project under the IPCC (ACCMIP/AeroCOM). This problem in global BC modeling, basically coming from aging and removal processes of BC, causes still a large uncertainty in the estimate of BC's atmospheric heating and climate impacts (Bond et al., 2013; Kerr et al., 2013). This study attempted to improve global simulation of BC by developing a new scheme for simulating aging process of BC and re-evaluate radiative forcing of BC in the framework of a chemistry-aerosol coupled climate model (Earth system model) MIROC-ESM-CHEM. Our improved model with the new aging scheme appears to relatively well reproduce the observed BC concentrations and seasonality in the Arctic/Antarctic region. The new model estimates radiative forcing of BC to be 0.83 W m-2 which is about two times larger than the estimate by our original model with no aging scheme (0.41 W m-2), or the model ensemble mean in the IPCC report. Using this model, future projection of SLCPs and their climate impacts is conducted following the recent IIASA emission scenarios for the year 2030 (Klimont et al., 2006; Cofala et al., 2007). Our simulation suggests that heating SLCPs components (O3, BC, and CH4) are significantly reduced in the maximal feasible reduction (MFR) scenario, contributing to global mean temperature reduction by about -0.25 oC after 2030. This heating-SLCPs-induced warming mitigation in MFR is, however, largely cancelled out by the temperature increase due to decreases in cooling aerosols (SO42-, NO3-, and organics), resulting in temperature projection which is not quite different from the other scenarios like CLE (current legislation for air quality) or 450ppm climate stabilization (intermediate reduction) scenario. References Bond et al. (2013): Bounding the role of black carbon in the climate system: A scientific assessment, J. Geophys. Res., 118, 5380-5552, doi:10.1002/jgrd.50171, 2013. Cofala et al. (2007): Scenarios of global anthropogenic emissions of air pollutants and methane until 2030, Atmos. Environ., 41, 8486-8499. Kerr et al. (2013): Soot is warming the world even more than thought, Science, 339, 382, doi: 10.1126/science.339.6118.382. Klimont, Z., Brink, C. (2006): Modelling of Emissions of Air Pollutants and Greenhouse Gases from Agricultural Sources in Europe. International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria. Shindell et al. (2012): Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security, Science, 335, 183-189, doi: 10.1126/science.1210026.

  8. Size distribution, chemical composition, and hygroscopicity of fine particles emitted from an oil-fired heating plant.

    PubMed

    Happonen, Matti; Mylläri, Fanni; Karjalainen, Panu; Frey, Anna; Saarikoski, Sanna; Carbone, Samara; Hillamo, Risto; Pirjola, Liisa; Häyrinen, Anna; Kytömäki, Jorma; Niemi, Jarkko V; Keskinen, Jorma; Rönkkö, Topi

    2013-12-17

    Heavy fuel oil (HFO) is a commonly used fuel in industrial heating and power generation and for large marine vessels. In this study, the fine particle emissions of a 47 MW oil-fired boiler were studied at 30 MW power and with three different fuels. The studied fuels were HFO, water emulsion of HFO, and water emulsion of HFO mixed with light fuel oil (LFO). With all the fuels, the boiler emitted considerable amounts of particles smaller than 200 nm in diameter. Further, these small particles were quite hygroscopic even as fresh and, in the case of HFO+LFO emulsion, the hygroscopic growth of the particles was dependent on particle size. The use of emulsions and the addition of LFO to the fuel had a reducing effect on the hygroscopic growth of particles. The use of emulsions lowered the sulfate content of the smallest particles but did not affect significantly the sulfate content of particles larger than 42 nm and, further, the addition of LFO considerably increased the black carbon content of particulate matter. The results indicate that even the fine particles emitted from HFO based combustion can have a significant effect on cloud formation, visibility, and air quality. PMID:24245691

  9. VLA Observations Confirm Origin of Gamma Ray Bursts in Short-Lived Stars

    NASA Astrophysics Data System (ADS)

    1998-06-01

    Radio telescope studies of the fiery afterglow of a Gamma Ray Burst have provided astronomers with the best clues yet about the origins of these tremendous cosmic cataclysms since their discovery more than 30 years ago. Observations with the National Science Foundation's (NSF) Very Large Array (VLA) radio telescope confirm that a blast seen to occur on March 29 had its origin in a star-forming region in a distant galaxy. "There are two leading theories for the causes of Gamma Ray Bursts," said Dale Frail of the NSF National Radio Astronomy Observatory (NRAO) in Socorro, NM. "According to one theory, the blasts occur in the death throes of pairs of old stars. The other requires them to arise from exploding, massive, short-lived stars that still reside within the star-forming gas and dust from which they formed. The VLA studies of the burst show that at least this one almost certainly occurred within a star-forming region. This result also explains why half of the Gamma Ray Burst afterglows are not detected by optical telescopes." Frail heads a VLA observing team including Greg Taylor, also of NRAO, and Shri Kulkarni of Caltech, that reported its findings to the American Astronomical Society meeting in San Diego, CA. The March 29 burst was seen clearly by radio telescopes (the accompanying image is GRB 980329 as seen by the VLA) but only very faintly with optical instruments. "That is extremely important," said Taylor. "This burst was very faint at visible wavelengths, brighter at infrared wavelengths and brighter still at radio wavelengths. This is a clear indication that the exploding object was surrounded by dust. Dust is most commonly found in star-forming regions." This strongly favors one of the two leading theories about Gamma Ray Bursts over the other. One explanation for these tremendously energetic fireballs is that a pair of superdense neutron stars collides. The other is that a single, very massive star explodes in a "hypernova," more powerful than a supernova, at the end of its normal life. The hypernova explosion, scientists believe, would come only a few million years after the giant star was formed, while it is still within the cloud of gas and dust from which it formed. Neutron stars, on the other hand, are formed by supernova explosions that give a "kick" to the resulting neutron star, propelling it at high speeds. An orbiting pair of neutron stars, astronomers think, would collide only after hundreds of millions of years of orbital decay, by which time they would be far away from the gas and dust of their birthplace. "The observations already have provided crucial insight; we intend to continue observing the relic of the March 29 burst with the VLA, and in the coming months, we will gain new information that will help further refine our ideas about these fireballs," Frail said. "We're going to learn about the size and expansion rate of the fireball and test predictions made by the models." "These observations indicate the extraordinary importance of radio astronomy for providing information that can be gained in no other way about one of the major frontier areas of astrophysics," said Hugh Van Horn, Director of the NSF's Division of Astronomical Sciences. The March 29 burst (GRB 980329) was the second such blast to have its afterglow detected at radio wavelengths. Last year, the VLA made the first radio detection of a GRB afterglow, finding radio emission coming from the location of a Gamma Ray Burst on May 8, 1997 (GRB 970508). "Of the world's radio telescopes, only the VLA has the sensitivity and resolving power to quickly detect these radio afterglows of Gamma Ray Bursts and study them in detail over extended periods of time," Taylor said. "Even so, we only see the brightest one-third of them. With upgraded capabilities at the VLA, as planned by NRAO, we will see them all." The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

  10. Actinium-225 in targeted alpha-particle therapeutic applications.

    PubMed

    Scheinberg, David A; McDevitt, Michael R

    2011-10-01

    Alpha particle-emitting isotopes are being investigated in radioimmunotherapeutic applications because of their unparalleled cytotoxicity when targeted to cancer and their relative lack of toxicity towards untargeted normal tissue. Actinium- 225 has been developed into potent targeting drug constructs and is in clinical use against acute myelogenous leukemia. The key properties of the alpha particles generated by 225Ac are the following: i) limited range in tissue of a few cell diameters; ii) high linear energy transfer leading to dense radiation damage along each alpha track; iii) a 10 day halflife; and iv) four net alpha particles emitted per decay. Targeting 225Ac-drug constructs have potential in the treatment of cancer. PMID:22202153

  11. Genome-wide determination of RNA stability reveals hundreds of short-lived noncoding transcripts in mammals

    PubMed Central

    Tani, Hidenori; Mizutani, Rena; Salam, Kazi Abdus; Tano, Keiko; Ijiri, Kenichi; Wakamatsu, Ai; Isogai, Takao; Suzuki, Yutaka; Akimitsu, Nobuyoshi

    2012-01-01

    Mammalian genomes produce huge numbers of noncoding RNAs (ncRNAs). However, the functions of most ncRNAs are unclear, and novel techniques that can distinguish functional ncRNAs are needed. Studies of mRNAs have revealed that the half-life of each mRNA is closely related to its physiological function, raising the possibility that the RNA stability of an ncRNA reflects its function. In this study, we first determined the half-lives of 11,052 mRNAs and 1418 ncRNAs in HeLa Tet-off (TO) cells by developing a novel genome-wide method, which we named 5′-bromo-uridine immunoprecipitation chase–deep sequencing analysis (BRIC-seq). This method involved pulse-labeling endogenous RNAs with 5′-bromo-uridine and measuring the ongoing decrease in RNA levels over time using multifaceted deep sequencing. By analyzing the relationship between RNA half-lives and functional categories, we found that RNAs with a long half-life (t1/2 ≥ 4 h) contained a significant proportion of ncRNAs, as well as mRNAs involved in housekeeping functions, whereas RNAs with a short half-life (t1/2 < 4 h) included known regulatory ncRNAs and regulatory mRNAs. The stabilities of a significant set of short-lived ncRNAs are regulated by external stimuli, such as retinoic acid treatment. In particular, we identified and characterized several novel long ncRNAs involved in cell proliferation from the group of short-lived ncRNAs. We designated this novel class of ncRNAs with a short half-life as Short-Lived noncoding Transcripts (SLiTs). We propose that the strategy of monitoring RNA half-life will provide a powerful tool for investigating hitherto functionally uncharacterized regulatory RNAs. PMID:22369889

  12. Design Study for a Multi-Reflection Time-of-Flight Mass Spectrograph for Very Short Lived Nuclei

    NASA Astrophysics Data System (ADS)

    Yoon, Jin Woo; Park, Young-Ho; Im, Kang-Bin; Kim, Gi Dong; Kim, Yong Kyun

    The multi-reflection time-of-flight mass spectrometer (MR-TOF-MS) has been designed for the high precision mass measurement system in RAON accelerator facility, which will be constructed in Korea. Mirror-electrode potentials were numerically optimized by Nelder-Mead algorithm. The temporal spread and the mass-resolving power were calculated for the 132Sn+ ions with an energy spread of 20 eV and an emittance of 3 π mm mrad; the mass resolving power over 105 was achieved. MR-TOF-MS will be used for the isobar separation and the mass measurement for very short-lived isotopes.

  13. Harvard-MIT research program in short-lived radiopharmaceuticals. Progress report, March 1, 1983-February 29, 1984

    SciTech Connect

    Adelstein, S.J.; Brownell, G.L.

    1984-02-01

    This report describes research efforts towards the achievement of a clearer understanding of the solution chemistry of technetium in order to facilitate the design of future clinical agents labeled with Tc-99m, the development of new receptor binding radiopharmaceuticals for the in vivo assessment of insulin receptors and for imaging the adrenal medulla and the brain, the examination of the utility of monoclonal antibodies and liposomes in the design of radiopharmaceuticals for diagnosis and therapy, and the synthesis of short-lived positron-emitting radiopharmaceuticals for transverse imaging of regional physiological processes.

  14. A rapid method for preparing undecalcified sections of bone for autoradiographic investigation with short-lived radionuclides

    SciTech Connect

    Savelkoul, T.J.; Visser, W.J.; Roelofs, J.M.; Lentferink, M.H.

    1983-01-01

    To prepare sections of undecalcified bone suitable both for autoradiography with short-lived radionuclides such as /sup 99m/Tc (t 1/2 . 6 hr) and for normal histology, rapid processing is necessary. By modifying the routine technique of embedding in plastic, sections can be obtained within 6 hours. The most important modification concerns the temperature used for the different steps in the process. The procedure has been used to localize /sup 99m/Tc labeled methylene diphosphonate for skeletal scintigraphy.

  15. Chemical Composition of Aerosol Particles Emitted by a Passenger Car Engine Fueled by Ethanol/Gasoline Mixtures

    NASA Astrophysics Data System (ADS)

    Medrano, J. M.; Gross, D. S.; Dutcher, D. D.; Drayton, M.; Kittelson, D.; McMurry, P.

    2007-12-01

    With concerns of national security, climate change, and human health, many people have called for oil independence for the United States and for the creation of alternative fuels. Ethanol has been widely praised as a viable alternative to petroleum-based fuels, due to the fact that it can be produced locally. A great deal of work has been done to characterize the energy balance of ethanol production versus consumption, but there have been fewer studies of the environmental and health impacts of emissions from combustion of ethanol/gasoline mixtures such as those burned in the modern vehicle fleet. To study the particulate emissions from such fuels, different ethanol/gasoline fuel mixtures with 0, 20, 40, and 85% ethanol were burned in a dynamometer-mounted automobile engine. The engine exhaust was diluted and sampled with two aerosol Time-of-Flight Mass Spectrometers (TSI 3800 ATOFMS), sampling different particle size ranges (50-500 nm and 150-3000 nm, respectively), to measure size and composition of the emitted aerosol particles. A variety of other aerosol characterization techniques were also employed to determine the size distribution of the aerosol particles, the mass emission rate from the engine, and the concentration of polycyclic aromatic hydrocarbons (PAHs) and elemental carbon (EC) in the particle emissions. Here we will focus on results from the ATOFMS, which provides us with a particle size and mass spectra - for both negative and positive ions - for each particle that is sampled. Particles being emitted were found to contain primarily PAHs, elemental carbon (EC), nitrates, and sulfates. Particles were analyzed to investigate trends in particle composition as a function of fuel ethanol content, particle size, and for the types of particles emitted. A trend in particle type as a function of fuel ethanol content was evident in smaller particles, and trends in composition as a function of particle size were visible across the entire size range sampled.

  16. Treatment of HER2 Positive Breast Carcinomatous Meningitis with Intrathecal Administration of ?-Particle Emitting 211At-labeled Trastuzumab?

    PubMed Central

    Boskovitz, Abraham; McLendon, Roger E.; Okamura, Tatsunori; Sampson, John H.; Bigner, Darell D.; Zalutsky, Michael R.

    2009-01-01

    Introduction Carcinomatous meningitis (CM) is a devastating disease characterized by the dissemination of malignant tumor cells into the subarachnoid space along the brain and spine. Systemic treatment with monoclonal antibody (mAb) trastuzumab can be effective against HER2-positive systemic breast carcinoma but like other therapies, is ineffective against CM. The goal of this study was to evaluate the therapeutic effect of ?-particle emitting 211At-labeled trastuzumab following intrathecal administration in a rat model of breast carcinoma CM. Methods Athymic rats were injected intrathecally with MCF-7/HER2-18 breast carcinoma cells through a surgically-implanted indwelling intrathecal catheter. In Experiment 1, animals received 33 or 66 Ci 211At-labeled trastuzumab, cold trastuzumab, or saline. In Experiment 2, animals were inoculated with a lower tumor burden and received 46 or 92 Ci 211At-labeled trastuzumab, or saline. In Experiment 3, animals received 28 Ci 211At-labeled trastuzumab, 30 Ci 211At-labeled TPS3.2 control mAb or saline. Histopathological analysis of the neuroaxis was performed at the end of the study. Results In Experiment 1, median survival increased from 21 days for the saline and cold trastuzumab groups to 45 and 48 days for 33 and 66 Ci 211At-labeled trastuzumab, respectively. In Experiment 2, median survival increased from 23 days for saline controls to 68 and 92 days for 46 and 92 Ci 211At-labeled trastuzumab, respectively. In Experiment 3, median survival increased from 20 days to 29 and 36 days for animals treated with 211At-labeled TPS3.2 and 211At-labeled trastuzumab, respectively. Long-term survivors were observed exclusively in the 211At-trastuzumab-treated groups. Conclusion Intrathecal 211At-labeled trastuzumab shows promise as a treatment for patients with HER2-positive breast CM. PMID:19647172

  17. Development and Application of A Membrane-Based Thermodenuder for Measurement of Volatile Particles Emitted by A Jet Turbine Engine

    SciTech Connect

    Cheng, Mengdawn

    2010-01-01

    Measurement of volatile particles emitted by modern jet engines is a daunting task. Besides the complexity in sampling jet aircraft exhaust, the main difficulty lies at how to faithfully capture the phase-partition dynamics of volatile particles as they travel downstream from the engine exhaust nozzle. As a result, the physico-chemical properties of the exhaust are also transformed. We have developed a sampling instrument that aims at enabling study of the phase-partition dynamics. The objective of this research project was to design and evaluate a new thermodenuder for performing phase separation of the engine-emitted volatile particles. The backbone of the new thermodenuder is a thin metallic membrane. The membrane enables extraction of molecules that can be thermally desorbed from the condensed particulate phases and collected for subsequent chemical analysis. Toward realization of the technique in the future field aircraft emissions measurement we tested this new thermo-denuding device using laboratory-generated particles that were made of non-volatile or semi-volatile chemicals. The particle penetration efficiency, a measure of the device performance, of this thermodenuder was found to be better than 99%. Results obtained from the tests executed at a number of operating temperature conditions show reasonably good thermal separation. We have scheduled to apply this new device to characterize emissions from a T63 turboshaft engine in the spring of 2010 and are expecting to show the engine results at the conference. The test results based on the laboratory-generated particles were encouraging for the intended application. With excellent particle transmission efficiency and an ability to simultaneously measure the composition in the gas and particle phases of the engine particles, we believe the new technology will make a great contribution to measurement research of engine emissions.

  18. Studies of images of short-lived events using ERTS data. [forest fires, oil spills, vegetation damage, volcanoes, storm ridges, earthquakes, and floods

    NASA Technical Reports Server (NTRS)

    Deutschman, W. A. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Detection of short-lived events has continued. Forest fires, oil spills, vegetation damage, volcanoes, storm ridges, earthquakes, and floods have been detected and analyzed.

  19. Production of Short-lived Radionuclides by Protons and Neutrons in Fe and Ni Targets: Cross Sections Needed for Cosmic Ray Studies

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.; Vincent, J.; Jones, D. T. L.; Binns, P. J.; Langen, K.; Schroeder, I.; Buthelezi, Z.; Brooks, F. D.; Buffler, A.; Allie, M. S.

    2000-01-01

    New neutron and proton cross sections for short-lived radionuclides produced in Fe and Ni are presented. These cross sections are essential to understand cosmic ray interactions with meteorites and the lunar surface.

  20. Alterations in oxidative, inflammatory and apoptotic events in short-lived and long-lived mice testes

    PubMed Central

    Matzkin, María Eugenia; Miquet, Johanna Gabriela; Fang, Yimin; Hill, Cristal Monique; Turyn, Daniel; Calandra, Ricardo Saúl; Bartke, Andrzej; Frungieri, Mónica Beatriz

    2016-01-01

    Aged testes undergo profound histological and morphological alterations leading to a reduced functionality. Here, we investigated whether variations in longevity affect the development of local inflammatory processes, the oxidative state and the occurrence of apoptotic events in the testis. To this aim, well-established mouse models with delayed (growth hormone releasing hormone-knockout and Ames dwarf mice) or accelerated (growth hormone-transgenic mice) aging were used. We hereby show that the testes of short-lived mice show a significant increase in cyclooxygenase 2 expression, PGD2 production, lipid peroxidation, antioxidant enzymes expression, local macrophages and TUNEL-positive germ cells numbers, and the levels of both pro-caspase-3 and cleaved caspase-3. In contrast, although the expression of antioxidant enzymes remained unchanged in testes of long-lived mice, the remainder of the parameters assessed showed a significant reduction. This study provides novel evidence that longevity confers anti-inflammatory, anti-oxidant and anti-apoptotic capacities to the adult testis. Oppositely, short-lived mice suffer testicular inflammatory, oxidative and apoptotic processes. PMID:26805572

  1. Application of the Non-Adiabatic Phase Matrix Method to Vibrational Excitation Near a Short-lived Resonance

    NASA Astrophysics Data System (ADS)

    Morrison, Michael A.; Mazevet, S.; Nesbet, R. K.

    1998-05-01

    Non-adiabatic effects arising from energy exchange between the kinetic energy of the projectile and the nuclear degrees of freedom play a vital role in resonance vibrational excitation of molecules for sufficiently long-lived resonances. The importance of these effects for short-lived resonances is less clear, and the suitability of approximate theories for incorporating these effects to such resonances has been heretofore unknown. We have applied one such approach, the non-adiabatic phase (NADP) matrix method,(R. K. Nesbet, Phys. Rev. A 54), 2899 (1996) to the very short-lived resonance in e--H2 vibrational excitation. Even in this problematic case, the NADP method provides a systematic treatment of the (fixed-nuclei) ^2Σ_u^+ resonance that is consistent for all internuclear separations. We shall compare NADP scattering quantities for excitation of low-lying vibrational states of H2 to benchmark results from body-fixed vibrational close-coupling calculations.(S. J. Buckman, M. J. Brunger, D. S. Newman, G. Snitchler, S. Alston, D. W. Norcross, M. A. Morrison, B. C. Saha, G. Danby, and W. K. Trail, Phys. Rev. Lett. 65), 3253 (1990)

  2. Calpain-generated natural protein fragments as short-lived substrates of the N-end rule pathway

    PubMed Central

    Piatkov, Konstantin I.; Oh, Jang-Hyun; Liu, Yuan; Varshavsky, Alexander

    2014-01-01

    Calpains are Ca2+-dependent intracellular proteases. We show here that calpain-generated natural C-terminal fragments of proteins that include G protein–coupled receptors, transmembrane ion channels, transcriptional regulators, apoptosis controllers, kinases, and phosphatases (Phe-GluN2a, Lys-Ica512, Arg-Ankrd2, Tyr-Grm1, Arg-Atp2b2, Glu-Bak, Arg-Igfbp2, Glu-IκBα, and Arg-c-Fos), are short-lived substrates of the Arg/N-end rule pathway, which targets destabilizing N-terminal residues. We also found that the identity of a fragment’s N-terminal residue can change during evolution, but the residue’s destabilizing activity is virtually always retained, suggesting selection pressures that favor a short half-life of the calpain-generated fragment. It is also shown that a self-cleavage of a calpain can result in an N-end rule substrate. Thus, the autoprocessing of calpains can control them by making active calpains short-lived. These and related results indicate that the Arg/N-end rule pathway mediates the remodeling of oligomeric complexes by eliminating protein fragments that are produced in these complexes through cleavages by calpains or other nonprocessive proteases. We suggest that this capability of the Arg/N-end rule pathway underlies a multitude of its previously known but mechanistically unclear functions. PMID:24550490

  3. Short-lived mammals (shrew, mouse) have a less robust metal-responsive transcription factor than humans and bats.

    PubMed

    Schmidt, Katharina; Steiner, Kurt; Petrov, Boyan; Georgiev, Oleg; Schaffner, Walter

    2016-06-01

    Non-essential "heavy" metals such as cadmium tend to accumulate in an organism and thus are a particular threat for long-lived animals. Here we show that two unrelated, short-lived groups of mammals (rodents and shrews, separated by 100 Mio years of evolution) each have independently acquired mutations in their metal-responsive transcription factor (MTF-1) in a domain relevant for robust transcriptional induction by zinc and cadmium. While key amino acids are mutated in rodents, in shrews an entire exon is skipped. Rodents and especially shrews are unique regarding the alterations of this region. To investigate the biological relevance of these alterations, MTF-1s from the common shrew (Sorex araneus), the mouse, humans and a bat (Myotis blythii), were tested by cotransfection with a reporter gene into cells lacking MTF-1. Whereas shrews only live for 1.5-2.5 years, bats, although living on a very similar insect diet, have a lifespan of several decades. We find that bat MTF-1 is similarly metal-responsive as its human counterpart, while shrew MTF-1 is less responsive, similar to mouse MTF-1. We propose that in comparison to most other mammals, the short-lived shrews and rodents can afford a "lower-quality" system for heavy metal homeostasis and detoxification. PMID:27067444

  4. Overview of the methods for the measurement and interpretation of short-lived radioisotopes and their limits

    NASA Astrophysics Data System (ADS)

    Ghaleb, B.

    2009-01-01

    The daughter products of the uranium and thorium series consist of several radioactive isotopes with half-lives varying from less than a second to 105 years. Combining their half-live with their geochemical behaviour some of these radioisotopes could be used as tracers and/or chronometers of sedimentary processes. For example, thorium isotopes, and to a lesser extent polonium isotopes are characterized by very low solubility and very high affinity for the surface of particles. Consequently, thorium isotopes can be used to document scavenging and adsorption processes. On the other hand, radium isotopes tend to remain in solution and can be used to document diffusion processes. In the following, we present the analytical methods for the measurement and analysis of the most common short-lived isotopes and throughout their utility in studying sedimentary processes will be illustrated by a few examples of applications. These examples will focus essentially on the applications of short lived thorium isotopes (notably 234Th) and the use of 210Pb as chronometer for recent sedimentary accumulation.

  5. Alterations in oxidative, inflammatory and apoptotic events in short-lived and long-lived mice testes.

    PubMed

    Matzkin, Mara Eugenia; Miquet, Johanna Gabriela; Fang, Yimin; Hill, Cristal Monique; Turyn, Daniel; Calandra, Ricardo Sal; Bartke, Andrzej; Frungieri, Mnica Beatriz

    2016-01-01

    Aged testes undergo profound histological and morphological alterations leading to a reduced functionality. Here, we investigated whether variations in longevity affect the development of local inflammatory processes, the oxidative state and the occurrence of apoptotic events in the testis. To this aim, well-established mouse models with delayed (growth hormone releasing hormone-knockout and Ames dwarf mice) or accelerated (growth hormone-transgenic mice) aging were used. We hereby show that the testes of short-lived mice show a significant increase in cyclooxygenase 2 expression, PGD2 production, lipid peroxidation, antioxidant enzymes expression, local macrophages and TUNEL-positive germ cells numbers, and the levels of both pro-caspase-3 and cleaved caspase-3. In contrast, although the expression of antioxidant enzymes remained unchanged in testes of long-lived mice, the remainder of the parameters assessed showed a significant reduction. This study provides novel evidence that longevity confers anti-inflammatory, anti-oxidant and anti-apoptotic capacities to the adult testis. Oppositely, short-lived mice suffer testicular inflammatory, oxidative and apoptotic processes. PMID:26805572

  6. Realizing the potential of the Actinium-225 radionuclide generator in targeted alpha-particle therapy applications

    PubMed Central

    Miederer, Matthias; Scheinberg, David A.; McDevitt, Michael R.

    2013-01-01

    Alpha particle-emitting isotopes have been proposed as novel cytotoxic agents for augmenting targeted therapy. Properties of alpha particle radiation such as their limited range in tissue of a few cell diameters and their high linear energy transfer leading to dense radiation damage along each alpha track are promising in the treatment of cancer, especially when single cells or clusters of tumor cells are targeted. Actinium-225 (225Ac) is an alpha particle-emitting radionuclide that generates 4 net alpha particle isotopes in a short decay chain to stable 209Bi, and as such can be described as an alpha particle nanogenerator. This article reviews the literature pertaining to the research, development, and utilization of targeted 225Ac to potently and specifically affect cancer. PMID:18514364

  7. Realizing the potential of the Actinium-225 radionuclide generator in targeted alpha particle therapy applications.

    PubMed

    Miederer, Matthias; Scheinberg, David A; McDevitt, Michael R

    2008-09-01

    Alpha particle-emitting isotopes have been proposed as novel cytotoxic agents for augmenting targeted therapy. Properties of alpha particle radiation such as their limited range in tissue of a few cell diameters and their high linear energy transfer leading to dense radiation damage along each alpha track are promising in the treatment of cancer, especially when single cells or clusters of tumor cells are targeted. Actinium-225 (225 Ac) is an alpha particle-emitting radionuclide that generates 4 net alpha particle isotopes in a short decay chain to stable 209 Bi, and as such can be described as an alpha particle nanogenerator. This article reviews the literature pertaining to the research, development, and utilization of targeted 225 Ac to potently and specifically affect cancer. PMID:18514364

  8. Analysis of Individual Carbonaceous Particles Emitted from the Las Conchas Wildfire, Los Alamos, NM, in June-July 2011

    NASA Astrophysics Data System (ADS)

    Mazzoleni, C.; China, S.; Gorkowski, K.; Flowers, B. A.; Aiken, A. C.; Dubey, M. K.

    2012-12-01

    Carbonaceous aerosol emitted from biomass burning contributes significantly to atmospheric aerosol loadings regionally and globally. The net direct radiative forcing of biomass burning aerosol can be positive and/or negative and this depends on its composition, morphology and mixing state. Biomass burning aerosols can also change the cloud properties as they can act as cloud condensation nuclei. In this study we investigated biomass burning particles emitted from the Las Conchas wildfire in northern New Mexico that started on June 26, 2011 and burned an area of 245 square miles. Aerosol samples were collected on nucleopore filters at the Los Alamos National Laboratory during the third week of the wildfire event. Individual particles (~4000) were investigated using field-emission scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS) to distinguish different carbonaceous particles and their shape, size, elemental composition and mixing state. A thermo-denuder was used to remove compounds that are volatile at temperatures up to 200 C, leaving behind the black carbon and any compounds that did not volatize completely. Smoke particles consisted of a) tar balls, which are amorphous spherical carbonaceous organic aerosols; b) organic particles with inorganic inclusions, c) soot particles and (d) soot with various inclusions. Two distinct kinds of tar balls, "electronically" dark and bright, were found using the field-emission scanning electron microscopy and were characterized for ambient and denuded conditions to understand coating effects and aging. It was found that dark tar balls are generally larger in size than the bright ones. Additionally, the difference between the size of ambient-bright and the size of denuded-bright tar balls was larger than the difference between the size of ambient-dark and the size of denuded-dark tar balls. EDS analysis showed that 70% of the dark tar balls had higher (~60%) relative oxygen content than in the bright tar balls. We conclude that there are two distinct kinds of biomass burning tar balls and that dark tar balls are less volatile than bright tar balls. The morphology of soot particles was also investigated by evaluating their fractal dimension for both ambient (coated with organic and inorganic material) and denuded samples at two different times of the day. The fractal dimension for ambient soot was found to be higher than for denuded soot due to the coating on the ambient soot particles. Finally, the monomer diameter decreased by up to 25% after denuding the particles. This study provides insights on the link between electron microscopy images of single particles and the mixing state, morphology, and evolution of different biomass burning aerosol at the beginning of their lifecycle.

  9. Optical detection of ESR spectra of short-lived ion-radical pairs produced in solution by ionizing radiation

    SciTech Connect

    Molin, Y.N.; Anisimov, O.A.; Grigoryants, V.M.; Molchanov, V.K.; Salikhov, K.M.

    1980-07-10

    A new and very sensitive technique to detect ESR spectra of short-lived radical pairs in solution is proposed on the basis of optical detection of magnetic resonance (ODMR). An ODMR spectrometer has been constructed for detecting ESR spectra of ion-radical pairs created by ionizing radiation. The singlet ESR signal from (naphthalene)-/(naphthalene)/sup +/ pairs has been observed in a naphthalene solution in squalene at an average concentration of 20 radical pairs per sample with a signal-to-noise ratio equal to 10/1. The hyperfine structure has been resolved in the ESR spectrum of (diphenyl)-/(diphenyl)/sup +/ pairs at a low diphenyl concentration in squalane and spectrum narrowing due to charge-transfer reaction has been observed at a high diphenyl concentration.

  10. Calcium influx through TRP channels induced by short-lived reactive species in plasma-irradiated solution.

    PubMed

    Sasaki, Shota; Kanzaki, Makoto; Kaneko, Toshiro

    2016-01-01

    Non-equilibrium helium atmospheric-pressure plasma (He-APP), which allows for a strong non-equilibrium chemical reaction of O2 and N2 in ambient air, uniquely produces multiple extremely reactive products, such as reactive oxygen species (ROS), in plasma-irradiated solution. We herein show that relatively short-lived unclassified reactive species (i.e., deactivated within approximately 10 min) generated by the He-APP irradiation can trigger physiologically relevant Ca(2+) influx through ruthenium red- and SKF 96365-sensitive Ca(2+)-permeable channel(s), possibly transient receptor potential channel family member(s). Our results provide novel insight into understanding of the interactions between cells and plasmas and the mechanism by which cells detect plasma-induced chemically reactive species, in addition to facilitating development of plasma applications in medicine. PMID:27169489

  11. Photo-Induced Assembly of Nanostructures Triggered by Short-Lived Proton Transfers in the Excited-State.

    PubMed

    Cardenas-Daw, Carlos; Gröhn, Franziska

    2015-07-15

    Light stimulation was used to trigger the assembly of nanostructures by directly powering changes at the supramolecular level without incurring net chemical changes at the molecular level. Polyethylene imine, a polybase, was mixed in aqueous solution with sodium 1-naphthol-4-sulfonate, an aromatic alcohol, which, in the electronic excited-state, undergoes a short-lived increase in acidity. Excited-state proton transfers between these components were induced by photoexcitation, which led to the formation of hydrogen bonds in the ground-state. Ionic forces, π-π stacking, and hydrophobic effect provided further stabilization. The photoinduced formation of nanosized aggregates was detected by dynamic light scattering and atomic force microscopy. Absorption and emission spectroscopy were used to rule out photochemical reactions and elucidate the supramolecular arrangement. PMID:26088975

  12. Nuclear photoactivation cross sections for short-lived isomeric states excited with a 6 MeV linac

    NASA Astrophysics Data System (ADS)

    Anderson, J. A.; Eberhard, C. D.; Byrd, M. J.; Carroll, J. J.; Collins, C. B.; Scarbrough, E. C.; Antich, P. P.

    1989-04-01

    Photoactivation cross sections for short-lived (T {1}/{2} < 20 s) isomeric states in 167Er, 79Br, 191Ir, 183W, 197Au, 77Se, 137Ba and 89Y were determined using bremsstrahlung from a 6 MeV medical therapy linac. A portable NaI(Tl) spectrometer and pneumatic transfer system was designed to avoid impacting normal use of the linac. Comparison with data obtained at the PITHON flash X-ray source (1.5 MeV endpoint energy) indicates that cross sections for populating these isomers through gateway states in the range 1.5-6 MeV are more than three orders of magnitude greater than corresponding cross sections below 1.5 MeV. The results are significant for the development of photoactivation techniques to measure short (<100 ns), nonreproducible bremsstrahlung pulses.

  13. Rituximab ameliorates anti-N-methyl-D-aspartate receptor encephalitis by removal of short-lived plasmablasts.

    PubMed

    Hachiya, Yasuo; Uruha, Akinori; Kasai-Yoshida, Emi; Shimoda, Konomi; Satoh-Shirai, Ikuko; Kumada, Satoko; Kurihara, Eiji; Suzuki, Kotoko; Ohba, Atsuko; Hamano, Shin-ichiro; Sakuma, Hiroshi

    2013-12-15

    We measured anti-N-methyl-D-aspartate receptor (NMDAR) autoantibody levels and assessed B cell subsets using multicolor flow cytometry of peripheral blood mononuclear cells (PBMCs) from a recurrent anti-NMDAR encephalitis case to evaluate the effectiveness of rituximab treatment. Rituximab depleted CD20(+) fractions of naïve and memory B cell subsets and reduced the number of CD20(-) plasmablasts. This study suggests that short-lived plasmablasts are removed by rituximab-induced depletion of the CD20(+) B cell population. Increased numbers of plasmablasts in PBMCs may be a candidate predictive factor for unfavorable prognosis of anti-NMDAR encephalitis and an indication of when to commence second-line immunotherapy. PMID:24183642

  14. Identifying and quantifying short-lived fission products from thermal fission of HEU using portable HPGe detectors

    SciTech Connect

    Pierson, Bruce D.; Finn, Erin C.; Friese, Judah I.; Greenwood, Lawrence R.; Kephart, Jeremy D.; Kephart, Rosara F.; Metz, Lori A.

    2013-03-01

    Due to the emerging potential for trafficking of special nuclear material, research programs are investigating current capabilities of commercially available portable gamma ray detection systems. Presented in this paper are the results of three different portable high-purity germanium (HPGe) detectors used to identify short-lived fission products generated from thermal neutron interrogation of small samples of highly enriched uranium. Samples were irradiated at the Washington State University (WSU) Nuclear Radiation Center’s 1MW TRIGA reactor. The three portable, HPGe detectors used were the ORTEC MicroDetective, the ORTEC Detective, and the Canberra Falcon. Canberra’s GENIE-2000 software was used to analyze the spectral data collected from each detector. Ultimately, these three portable detectors were able to identify a large range of fission products showing potential for material discrimination.

  15. Prompt gamma activation analysis (PGAA) and short-lived neutron activation analysis (NAA) applied to the characterization of legacy materials

    SciTech Connect

    Firestone, Richard B; English, G.A.; Firestone, R.B.; Perry, D.L.; Reijonen, J.P.; Leung, Ka-Ngo; Garabedian, G.F.; Molnar, G.L.; Revay, Zs.

    2008-02-13

    Without quality historical records that provide the composition of legacy materials, the elemental and/or chemical characterization of such materials requires a manual analytical strategy that may expose the analyst to unknown toxicological hazards. In addition, much of the existing legacy inventory also incorporates radioactivity, and, although radiological composition may be determined by various nuclear-analytical methods, most importantly, gamma-spectroscopy, current methods of chemical characterization still require direct sample manipulation, thereby presenting special problems with broad implications for both the analyst and the environment. Alternately, prompt gamma activation analysis (PGAA) provides a'single-shot' in-situ, non-destructive method that provides a complete assay of all major entrained elemental constituents.1-3. Additionally, neutron activation analysis (NAA) using short-lived activation products complements PGAA and is especially useful when NAA activation surpasses the PGAA in elemental sensitivity.

  16. First Isochronous Time-of-Flight Mass Measurements of Short-Lived Projectile Fragments in the ESR

    SciTech Connect

    Stadlmann, J.; Geissel, H.; Hausmann, M.; Nolden, F.; Radon, T.; Schatz, H.; Scheidenberger, C.; Attallah, F.; Beckert, K.; Bosch, F.; Falch, M.; Franczak, B.; Franzke, B.; Kerscher, Th.; Klepper, O.; Kluge, H.J.; Kozhuharov, C.; Loebner, K.E.G.; Muenzenberg, G.; Novikov, Yu.N.; Steck, M.; Sun, Z.; Suemmerer, K.; Weick, H.; Wollnik, H.

    2000-12-31

    A new method for precise mass measurements of short-lived hot nuclei is presented. These nuclei were produced via projectile fragmentation, separated with the FRS and injected into the storage ring ESR being operated in the isochronous mode. The revolution time of the ions is measured with a time-of-flight detector sensitive to single particles. This new method allows access to exotic nuclei with half-lives in the microsecond region. First results from this novel method obtained with measurements on neutron-deficient fragments of a chromium primary beam with half-lives down to 50 ms are reported. A precision of {delta}m/m {<=} 5 {center_dot} 10{sup -6} has been achieved.

  17. Calcium influx through TRP channels induced by short-lived reactive species in plasma-irradiated solution

    PubMed Central

    Sasaki, Shota; Kanzaki, Makoto; Kaneko, Toshiro

    2016-01-01

    Non-equilibrium helium atmospheric-pressure plasma (He-APP), which allows for a strong non-equilibrium chemical reaction of O2 and N2 in ambient air, uniquely produces multiple extremely reactive products, such as reactive oxygen species (ROS), in plasma-irradiated solution. We herein show that relatively short-lived unclassified reactive species (i.e., deactivated within approximately 10 min) generated by the He-APP irradiation can trigger physiologically relevant Ca2+ influx through ruthenium red- and SKF 96365-sensitive Ca2+-permeable channel(s), possibly transient receptor potential channel family member(s). Our results provide novel insight into understanding of the interactions between cells and plasmas and the mechanism by which cells detect plasma-induced chemically reactive species, in addition to facilitating development of plasma applications in medicine. PMID:27169489

  18. Using Atmospheric Dispersion Theory to Inform the Design of a Short-lived Radioactive Particle Release Experiment.

    PubMed

    Rishel, Jeremy P; Keillor, Martin E; Arrigo, Leah M; Baciak, James E; Detwiler, Rebecca S; Kernan, Warnick J; Kirkham, Randy R; Milbrath, Brian D; Seifert, Allen; Seifert, Carolyn E; Smart, John E

    2016-05-01

    Atmospheric dispersion theory can be used to predict ground deposition of particulates downwind of a radionuclide release. This paper uses standard formulations found in Gaussian plume models to inform the design of an experimental release of short-lived radioactive particles into the atmosphere. Specifically, a source depletion algorithm is used to determine the optimum particle size and release height that maximizes the near-field deposition while minimizing both the required source activity and the fraction of activity lost to long-distance transport. The purpose of the release is to provide a realistic deposition pattern that might be observed downwind of a small-scale vent from an underground nuclear explosion. The deposition field will be used, in part, to study several techniques of gamma radiation survey and spectrometry that could be used by an On-Site Inspection team investigating such an event. PMID:27023039

  19. Constraints on the Origin of Chondrules and CAIs from Short-lived and Long-lived Radionuclides

    NASA Technical Reports Server (NTRS)

    Kita, N. T.; Huss, G. R.; Tachibana, S.; Amelin, Y.; Zinner, E.; Nyquist, L. E.; Hutcheon, I. D.

    2004-01-01

    In order to understand the timing of events in the early solar system, we rely on the radio-nuclide-based chronometers applied to materials in primitive meteorites. Because the time scale of early-solar system evolution was on the order of a few million years (Myr), we focus on so-called "short-lived radionuclides" with mean lives of less than 10 Myr (Table 1), as well as on the long-lived U-Pb system where high precision 207Pb-206Pb ages are applied. Note that the validity of some systems as chronometers (e.g., Be-B, Fe-Ni) has yet to be established. We summarize literature data for chondrules and CAIs and discuss how these chronometers constrain formation time scales in the early solar system.

  20. Corrections for the combined effects of decay and dead time in live-timed counting of short-lived radionuclides.

    PubMed

    Fitzgerald, R

    2016-03-01

    Studies and calibrations of short-lived radionuclides, for example (15)O, are of particular interest in nuclear medicine. Yet counting experiments on such species are vulnerable to an error due to the combined effect of decay and dead time. Separate decay corrections and dead-time corrections do not account for this issue. Usually counting data are decay-corrected to the start time of the count period, or else instead of correcting the count rate, the mid-time of the measurement is used as the reference time. Correction factors are derived for both those methods, considering both extending and non-extending dead time. Series approximations are derived here and the accuracy of those approximations are discussed. PMID:26682893

  1. Thyroid cancer in the Marshallese: relative risk of short-lived internal emitters and external radiation exposure

    SciTech Connect

    Lessard, E.T.; Brill, A.B.; Adams, W.H.

    1985-01-01

    In a study of the comparative effects of internal versus external irradiation of the thyroid in young people, we determined that the dose from internal irradiation of the thyroid with short-lived internal emitters produced several times less thyroid cancer than did the same dose of radiation given externally. We determined this finding for a group of 85 Marshall Islands children, who were less than 10 years of age at the time of exposure and who were accidentially exposed to internal and external thyroid radiation at an average level of 1400 rad. The external risk coefficient ranged between 2.5 and 4.9 cancers per million person-rad-years at risk, and thus, from our computations, the internal risk coefficient for the Marshallese children was estimated to range between 1.0 and 1.4 cancers per million person-rad-years at risk. In contrast, for individual more than 10 years of age at the time of exposure, the dose from internal irradiation of the thyroid with short-lived internal emitters produced several times more thyroid cancer than did the same dose of radiation given externally. The external risk coefficients for the older age groups were reported in the literature to be in the range of 1.0 to 3.3 cancers per million person-rad-years-at risk. We computed internal risk coefficients of 3.3 to 8.1 cancers per million person-rad-years at risk for adolescent and adult groups. This higher sensitivity to cancer induction in the exposed adolescents and adults, is different from that seen in other exposed groups. 14 refs., 8 tabs.

  2. ON THE INJECTION OF SHORT-LIVED RADIONUCLIDES FROM A SUPERNOVA INTO THE SOLAR NEBULA: CONSTRAINTS FROM THE OXYGEN ISOTOPES

    SciTech Connect

    Liu, Ming-Chang

    2014-02-01

    Injection of short-lived radionuclides from a nearby core-collapse Type II supernova into the already-formed solar protoplanetary disk was proposed to account for the former presence of {sup 26}Al, {sup 41}Ca, and {sup 60}Fe in the early solar system inferred from isotopic analysis of meteoritic samples. One potential corollary of this ''late-injection'' scenario is that the disk's initial (pre-injection) oxygen isotopic composition could be significantly altered, as supernova material that carried the short-lived radionuclides would also deliver oxygen components synthesized in that given star. Therefore, the change in the oxygen isotopic composition of the disk caused by injection could in principle be used to constrain the supernova injection models. Previous studies showed that although supernova oxygen could result in a wide range of shifts in {sup 17}O/{sup 16}O and {sup 18}O/{sup 16}O of the disk, a couple of cases existed where the calculated oxygen changes in the disk would be compatible with the meteoritic and solar wind data. Recently, the initial abundances of {sup 41}Ca and {sup 60}Fe in the solar system were revised to lower values, and the feasibility of supernova injection as a source for the three radionuclides was called into question. In this study, supernova parameters needed for matching {sup 26}Al, {sup 41}Ca, and {sup 60}Fe to their early solar system abundances were reinvestigated and then were used to infer the pre-injection O-isotope composition of the disk. The result suggested that a supernova undergoing mixing fallback might be a viable source for the three radionuclides.

  3. Effects of East Asian Short-lived Anthropogenic Air Pollutants on the Northern Hemispheric Air Quality and Climate

    NASA Astrophysics Data System (ADS)

    Liu, J.; Horowitz, L. W.; Lau, N.; Fan, S.; Tao, S.; Mauzerall, D. L.; Levy, H.

    2012-12-01

    Short-lived anthropogenic pollutants (such as ozone and aerosols) not only degrade ambient air quality and influence human health, but also play an important role in scattering/absorbing atmospheric radiation and disturbing regional climate. Due to the rapid industrialization, anthropogenic emissions from East Asia (EA) have increased substantially during the past decades. At the same time, EA has experienced a changing climate in terms of surface temperature and precipitation. In order to understand to what extent that EA short-lived anthropogenic emissions could influence domestic and downwind air quality (e.g. surface O3 and PM2.5), and explore the potential linkage between hemispheric-scale climate perturbation and regional anthropogenic forcing, we simulate global climate and chemical compositions during 1981-2000 based on the coupled general circulation model CM3 for atmosphere (with interactive tropospheric and stratospheric chemistry), oceans, land and sea ice, recently developed at Geophysical Fluid Dynamics Laboratory (GFDL/NOAA). We also conduct a parallel sensitivity simulation which is identical to the base simulation but with all anthropogenic emissions over EA turned off. The difference between the base and sensitivity simulations represents the short-term response of the Northern Hemispheric climate system and atmospheric composition to the perturbation of regional anthropogenic forcing. We find that East Asian short-lived anthropogenic emissions exert significant adverse impacts on local air quality during 1981-2000, accounting for 10-30ppbV daily-averaged O3 over Eastern China in JJA. In particular, EA anthropogenic emissions elevate the summertime daily maximum 8-hour average ozone (MDA8 O3) by 30-40ppbV over the North China Plain, where the typical background MDA8 ozone ranges 30 to 45ppbV. In addition, the surface PM2.5 concentrations peak at the same season and over the same region, with a seasonal mean of 10-30ug/m3, mostly contributed from local anthropogenic sources. In terms of long-range transport, anthropogenic pollutants from EA generally account for 2-5ppbv surface ozone from east to west mid-latitude North Pacific, but with distinct seasonal variability. During spring, EA anthropogenic emissions enhance nearly 2ppbV ozone over the west coast of California, USA, which increases the number of days when MADA8 exceeds 75ppbV by 2~5days/season in JJA. We find that the high aerosol loadings over EA significantly elevate aerosol optical depth (AOD) over Eastern China (0.2-0.4 in DJF and 0.3-0.5 in JJA), which warms up the atmosphere (15~20 Watts/m2) at the expense of cooling the surface (-30~-20 Watts/m2), potentially reducing the local surface temperature by -0.5K ~ -2K. Moreover, our model results also show that EA anthropogenic pollutants significantly depress local precipitation rate (up to 1.5 mm/day) and rain frequency (4-10 days/season), particularly over South and Southwestern China. This may partly explain the change of seasonal precipitation patterns over EA during the past decades.

  4. Li and B isotopic variations in an Allende CAI: Evidence for the in situ decay of short-lived 10Be and for the possible presence of the short-lived nuclide 7Be in the early solar system

    NASA Astrophysics Data System (ADS)

    Chaussidon, Marc; Robert, François; McKeegan, Kevin D.

    2006-01-01

    The concentrations and isotopic compositions of lithium, beryllium, and boron, analyzed in situ by ion microprobe in 66 spots of a type B1 Ca-Al-rich inclusion (CAI 3529-41) from the Allende meteorite, are reported. Large variations are observed for both the Li and the B isotopic ratios with 7Li/ 6Li ranging from 9.2 ± 0.22 to 12.22 ± 0.43 (a ≈250‰ range in δ7Li values) and 10B/ 11B ranging from 0.2468 ± 0.0057 to 0.4189 ± 0.0493 (a 410‰ range in δ11B values). The very low Li concentrations (<1 ppb) observed in several anorthite and fassaite grains require that a correction for the contribution of spallogenic Li produced during irradiation of the Allende meteoroid by galactic cosmic rays (GCR) be made (after this correction 7Li/ 6Li ranges from 9.2 ± 0.22 to 13.44 ± 0.56, i.e., a ≈350‰ range in δ7Li values). In 3529-41, the 10B/ 11B ratios are positively correlated with 9Be/ 11B in a manner indicating the in situ decay of short-lived 10Be (half-life = 1.5 Ma) with a 10Be/ 9Be ratio at the time of formation of the CAI of 8.8 ± 0.6 × 10 -4, which is in agreement with previous findings [McKeegan, K.D., Chaussidon, M., Robert, F., 2000. Incorporation of short-lived 10Be in a calcium-aluminum-rich inclusion from the Allende meteorite. Science289, 1334-1337]. The present detailed investigation demonstrates that only minor perturbations of the 10Be- 10B system are present in 3529-41, contrary to the 26Al/ 26Mg system for which numerous examples of isotopic redistribution following crystallization were observed [Podosek, F.A., Zinner, E.K., MacPherson, G.J., Lundberg, L.L., Brannon, J.C., Fahey, A.J., 1991. Correlated study of initial 87Sr/ 86Sr and Al-Mg systematics and petrologic properties in a suite of refractory inclusions from the Allende meteorite. Geochim. Cosmochim. Acta55, 1083-1110]. Petrographically based criteria were developed to identify within the 66 analyzed spots in 3529-41, those where post-magmatic perturbation of the Li and Be distributions occurred. Li and Be concentrations measured in different analytical spots are compared with those predicted by using experimentally determined partition coefficients according to a model of closed-system crystallization of the CAI melt. These criteria show that 56% of the spots in melilite, 38% in anorthite, and 8% in fassaite suffered post-crystallization perturbations of Li and/or Be distributions. In the remaining spots, which do not show obvious indication of redistribution of Li or Be, the 7Li/ 6Li isotopic variations (corrected for GCR exposure) are positively correlated with 9Be/ 6Li suggesting the in situ decay of now-extinct 7Be. The derived isochron implies that at the time of its formation, the CAI melt had a 7Be/ 9Be ratio of 0.0061 ± 0.0013 and a 7Li/ 6Li ratio of 11.49 ± 0.13. In contrast, all the spots in 3529-41, which do show evidence for post-magmatic redistribution of Li and Be, have relatively constant 7Li/ 6Li, averaging 11.72 ± 0.56, which is consistent with mass balance calculations for Li isotopic homogenization in the CAI after the decay of 7Be. The incorporation of live 7Be in 3529-41 requires, because of the very short half-life of this nuclide (53 days), that it be produced essentially contemporaneously with the formation of the CAI. Therefore, the irradiation processes responsible for production of 7Be must have occurred within the solar accretion disk. Calculations developed in the framework of the x-wind model [Gounelle, M., Shu, F.H., Shang, H., Glassgold, A.E., Rehm, E.K., Lee, T., 2004. The origin of short-lived radionuclides and early Solar System irradiation (abstract). Lunar Planet. Sci.35, 1829] reproduce the 7Be and 10Be abundances observed in 3529-41. The correlated presence of 7Be and 10Be in 3529-41 is thus a strong argument that 10Be, which is observed rather ubiquitously in CAIs, is also a product of irradiation in the early solar system, as might be a significant fraction of other short-lived radionuclides observed in early solar system materials.

  5. Public health benefits of strategies to reduce greenhouse-gas emissions: health implications of short-lived greenhouse pollutants

    PubMed Central

    Smith, Kirk R.; Jerrett, Michael; Anderson, H Ross; Burnett, Richard T.; Stone, Vicki; Derwent, Richard; Atkinson, Richard W.; Cohen, Aaron; Shonkoff, Seth B.; Krewski, Daniel; Pope, C. Arden; Thun, Michael J.; Thurston, George

    2014-01-01

    In this report we review the health effects of three short-lived greenhouse pollutants—black carbon, ozone, and sulphates. We undertook new meta-analyses of existing time-series studies and an analysis of a cohort of 352 000 people in 66 US cities during 18 years of follow-up. This cohort study provides estimates of mortality effects from long-term exposure to elemental carbon, an indicator of black carbon mass, and evidence that ozone exerts an independent risk of mortality. Associations among these pollutants make drawing conclusions about their individual health effects difficult at present, but sulphate seems to have the most robust effects in multiple-pollutant models. Generally, the toxicology of the pure compounds and their epidemiology diverge because atmospheric black carbon, ozone, and sulphate are associated and could interact with related toxic species. Although sulphate is a cooling agent, black carbon and ozone could together exert nearly half as much global warming as carbon dioxide. The complexity of these health and climate effects needs to be recognised in mitigation policies. PMID:19942276

  6. Comparison of short-lived medical isotopes activation by laser thin target induced protons and conventional cyclotron proton beams

    NASA Astrophysics Data System (ADS)

    Murray, Joseph; Dudnikova, Galina; Liu, Tung-Chang; Papadopoulos, Dennis; Sagdeev, Roald; Su, J. J.; UMD MicroPET Team

    2014-10-01

    Production diagnostic or therapeutic nuclear medicines are either by nuclear reactors or by ion accelerators. In general, diagnostic nuclear radioisotopes have a very short half-life varying from tens of minutes for PET tracers and few hours for SPECT tracers. Thus supplies of PET and SPECT radiotracers are limited by regional production facilities. For example 18F-fluorodeoxyglucose (FDG) is the most desired tracer for positron emission tomography because its 110 minutes half-life is sufficient long for transport from production facilities to nearby users. From nuclear activation to completing image taking must be done within 4 hours. Decentralized production of diagnostic radioisotopes will be idea to make high specific activity radiotracers available to researches and clinicians. 11 C, 13 N, 15 O and 18 F can be produced in the energy range from 10-20 MeV by protons. Protons of energies up to tens of MeV generated by intense laser interacting with hydrogen containing targets have been demonstrated by many groups in the past decade. We use 2D PIC code for proton acceleration, Geant4 Monte Carlo code for nuclei activation to compare the yields and specific activities of short-lived isotopes produced by cyclotron proton beams and laser driven protons.

  7. Occurrence of adventitious sprouting in short-lived monocarpic herbs: a field study of 22 weedy species

    PubMed Central

    Malíková, Lenka; Šmilauer, Petr; Klimešová, Jitka

    2010-01-01

    Background and Aims Adventitious sprouting from the hypocotyle and roots in monocarpic herbs has been confirmed in previous experimental studies as a means to avoid bud limitation after severe injury in annual and biennial plants. Data regarding the role of adventitious sprouting in natural populations, however, were lacking. The aim of the present study was to assess whether adventitious sprouting occurs in natural populations and how it is affected by plant size, plant injury, plant cover and environmental characteristics. Methods Data were sampled from 14 037 individual plants from 389 populations belonging to 22 annual and biennial species. Growth parameters were measured in individual plants, species composition and plant cover in communities were evaluated, and environmental characteristics were estimated using Ellenberg indicator values. Key Results It was confirmed that adventitious sprouting occurs in natural populations of all but five species examined. Adventitious sprouting was positively affected by plant size and plant injury. Environmental factors including availability of soil nitrogen were not shown to affect adventitious sprouting. Annual and biennial plants did not differ in sprouting, but upright annuals had a lower number of and longer adventitious shoots than prostrate annuals. Conclusions Adventitious bud formation is used to overcome meristem limitation when stem parts are lost due to injury, and thus resprouting in short-lived monocarps should not be overlooked. PMID:20356953

  8. Excited states of tryptophan in cod parvalbumin. Identification of a short-lived emitting triplet state at room temperature.

    PubMed Central

    Sudhakar, K; Phillips, C M; Williams, S A; Vanderkooi, J M

    1993-01-01

    The fluorescence and phosphorescence spectra of model indole compounds and of cod parvalbumin III, a protein containing a single tryptophan and no tyrosine, were examined in the time scale ranging from subnanoseconds to milliseconds at 25 degrees C in aqueous buffer. For both Ca- bound and Ca-free parvalbumin and for model indole compounds that contained a proton donor, a phosphorescent species emitting at 450 nm with a lifetime of approximately 20-40 ns could be identified. A longer-lived phosphorescence is also apparent; it has approximately the same absorption and emission spectrum as the short-lived triplet molecule. For Ca parvalbumin, the decay of the long-lived triplet tryptophan is roughly exponential with a lifetime of 4.7 ms at 25 degrees C whereas for N-acetyltryptophanamide in aqueous buffer the decay lifetime was 30 microseconds. In contrast, the lifetime of the long-lived tryptophan species is much shorter in the Ca-free protein compared with Ca parvalbumin, and the decay shows complex nonexponential kinetics over the entire time range from 100 ns to 1 ms. It is concluded that the photochemistry of tryptophan must take into account the existence of two excited triplet species and that there are quenching moieties within the protein matrix that decrease the phosphorescence yield in a dynamic manner for the Ca-depleted parvalbumin. In contrast, for Ca parvalbumin, the tryptophan site is rigid on the time scale of milliseconds. PMID:8324187

  9. Impact of Very Short-lived Halogens on Stratospheric Ozone Abundance and UV radiation in a Geo-engineered Atmosphere

    NASA Astrophysics Data System (ADS)

    Tilmes, S.; Kinnison, D. E.; Garcia, R. R.; Salawitch, R. J.; Canty, T. P.; Lee-Taylor, J.; Madronich, S.; Chance, K.

    2012-12-01

    The impact of BrO from very short-lived (VSL) source species on stratospheric ozone is investigated for a hypothetical geo-engineered atmosphere in 2040, assuming the injection of sulfuric acid aerosols. An estimated amount of stratospheric halogens from VSL sources based on satellite observations, model results and previous studies, result in lower column ozone for nearly all seasons and nearly all latitudes, and up to 4% in summer mid- and high latitudes. Considering an upper limit of VSL sources, the annual increase in surface erythemal UV radiation (UV_ERY) due to the decrease in ozone as a result of geo-engineering is 12% and 6% in southern and northern high latitudes, respectively. The increase of UV_ERY due to a reduction of ozone for low and mid latitudes is balanced by the reduction of UV_ERY due to aerosol scattering, if VSL halogen sources are not considered. However, VSL halogens results in additional ozone depletion and in an increase of UV_ERY of up to 5% in spring and fall in mid- and high latitudes as a result of geo-engineering. This study demonstrates that VSL halogens should be considered in models that assess the impact of stratospheric sulfur injections on the ozone layer.

  10. Impact of very short-lived halogens on stratospheric ozone abundance and UV radiation in a geo-engineered atmosphere

    NASA Astrophysics Data System (ADS)

    Tilmes, S.; Kinnison, D. E.; Garcia, R. R.; Salawitch, R.; Canty, T.; Lee-Taylor, J.; Madronich, S.; Chance, K.

    2012-11-01

    The impact of very short-lived (VSL) halogenated source species on the ozone layer and surface erythemal ultraviolet radiation (UVERY) is investigated in the context of geo-engineering of climate by stratospheric sulfur injection. For a projected 2040 model atmosphere, consideration of VSL halogens at their upper limit results in lower ozone columns and higher UVERY due to geo-engineering for nearly all seasons and latitudes, with UVERY rising by 12% and 6% in southern and northern high latitudes, respectively. When VSL halogen sources are neglected, future UVERY increases due to declines in ozone column are nearly balanced by reductions of UVERY due to scattering by the higher stratospheric aerosol burden in mid-latitudes. Consideration of VSL sources at their upper limit tips the balance, resulting in annual average increases in UVERY of up to 5% in mid and high latitudes. Therefore, VSL halogens should be considered in models that assess the impact of stratospheric sulfur injections on the ozone layer.

  11. Impact of very short-lived halogens on stratospheric ozone abundance and UV radiation in a geo-engineered atmosphere

    NASA Astrophysics Data System (ADS)

    Tilmes, S.; Kinnison, D. E.; Garcia, R. R.; Salawitch, R.; Canty, T.; Lee-Taylor, J.; Madronich, S.; Chance, K.

    2012-08-01

    The impact of very short-lived (VSL) halogenated source species on the ozone layer and surface erythemal ultraviolet radiation (UVERY) is investigated in the context of geo-engineering of climate by stratospheric sulfur injection. For a projected 2040 model atmosphere, consideration of VSL halogens at their upper limit results in lower ozone columns and higher UVERY due to geo-engineering for nearly all seasons and latitudes, with UVERY rising by 12% and 6% in southern and northern high latitudes, respectively. When VSL halogen sources are neglected, future UVERY increases due to declines in ozone column are nearly balanced by reductions of UVERY due to scattering by the higher stratospheric aerosol burden in mid-latitudes. Consideration of VSL sources at their upper limit tips the balance, resulting in annual average increases in UVERY of up to 5% in mid and high latitudes. Therefore, VSL halogens should be considered in models that assess the impact of stratospheric sulfur injections on the ozone layer.

  12. The investigation of properties of short-lived SF isotopes (Z > 100) at the focal plane of VASSILISSA separator

    NASA Astrophysics Data System (ADS)

    Svirikhin, Alexandr; Andreev, Alexander; Dushin, Victor; Chelnokov, Maxim; Chepigin, Victor; Gupta, Mohini; Isaev, Andrey; Izosimov, Igor; Katrasev, Denis; Kuznetsov, Alexey; Malyshev, Oleg; Minkova, Ani; Mullins, Simon; Popeko, Andrey; Sokol, Evgeniy; Yeremin, Alexander

    2013-12-01

    For experiments aimed at the study of spontaneous fission of transfermium nuclei improvements in the focal plane detector system of recoil separator VASSILISSA have been made. A neutron detector consisting of 54 3He-filled counters has been mounted around the focal-plane detector chamber. The reaction 48Ca + 206Pb = 2n + 252No is used for tuning the separator settings and calibrating the detector system with the spontaneous fission of the 252No. The average neutron number per 252No spontaneous fission event is as large as ν̅ = 4.06 ± 0.12. The short-lived heavy isotopes 244,246Fm, produced in the complete fusion reactions 40Ar + 206,208Pb, are investigated. The average number of neutrons per spontaneous fission of 244,246Fm from the experimental data were (ν̅ = 3.3 ± 0.3) and (ν̅ = 3.55 ± 0.50), respectively. Both values are determined for the first time.

  13. Plasmacytoid dendritic cells are short-lived: reappraising the influence of migration, genetic factors and activation on estimation of lifespan

    PubMed Central

    Zhan, Yifan; Chow, Kevin V.; Soo, Priscilla; Xu, Zhen; Brady, Jamie L.; Lawlor, Kate E.; Masters, Seth L.; O’keeffe, Meredith; Shortman, Ken; Zhang, Jian-Guo; Lew, Andrew M.

    2016-01-01

    Plasmacytoid dendritic cells (pDCs) play an important role in immunity to certain pathogens and immunopathology in some autoimmune diseases. They are thought to have a longer lifespan than conventional DCs (cDCs), largely based on a slower rate of BrdU labeling by splenic pDCs. Here we demonstrated that pDC expansion and therefore BrdU labeling by pDCs occurs in bone marrow (BM). The rate of labeling was similar between BM pDCs and spleen cDCs. Therefore, slower BrdU labeling of spleen pDCs likely reflects the “migration time” (∼2 days) for BrdU labeled pDCs to traffic to the spleen, not necessarily reflecting longer life span. Tracking the decay of differentiated DCs showed that splenic pDCs and cDCs decayed at a similar rate. We suggest that spleen pDCs have a shorter in vivo lifespan than estimated utilizing some of the previous approaches. Nevertheless, pDC lifespan varies between mouse strains. pDCs from lupus-prone NZB mice survived longer than C57BL/6 pDCs. We also demonstrated that activation either positively or negatively impacted on the survival of pDCs via different cell-death mechanisms. Thus, pDCs are also short-lived. However, the pDC lifespan is regulated by genetic and environmental factors that may have pathological consequence. PMID:27112985

  14. Time-resolved absorption and resonance Raman investigations of short-lived intermediates in solution or occluded in zeolites

    NASA Astrophysics Data System (ADS)

    Brémard, C.; Buntinx, G.; De Waele, V.; Didierjean, C.; Gener, I.; Poizat, O.

    1999-05-01

    Two examples of structural investigation of photogenerated short-lived transient species of aromatic compounds, by using time-resolved electronic absorption and resonance Raman spectroscopy are provided. The picosecond Raman spectra of the lowest excited singlet state (S 1) of 4,4'-bipyridine and 2,2'-bipyridine in solution are discussed first. The results provide strong evidence for a surprising asymmetric S 1 structure in which the electronic excitation and the consequent structural distortion are localized in one of the pyridyl rings, the other ring being almost unaffected. The laser photolysis of biphenyl occluded in the pores and cavities of ZSM-5 and faujasitic zeolites have been investigated in the nanosecond time-scale as functions of aluminium content, the extraframework cations, sample loading and intensity of photolysis. At low pump power and low aluminium content the triplet state of biphenyl is observed. At higher pump power and in aluminated zeolites, biphotonic ionization was observed to generate the cation radical. As the loading increased, the anion radical yield increased. This is characteristic of faujasitic zeolites in which scavenger molecules with restricted diffusional motions are confined in the vicinity of photoionized molecules. The lifetimes of cation radical were particularly long in aluminated ZSM-5 zeolites with efficient trapping sites of the photoejected electron.

  15. Plasmacytoid dendritic cells are short-lived: reappraising the influence of migration, genetic factors and activation on estimation of lifespan.

    PubMed

    Zhan, Yifan; Chow, Kevin V; Soo, Priscilla; Xu, Zhen; Brady, Jamie L; Lawlor, Kate E; Masters, Seth L; O'keeffe, Meredith; Shortman, Ken; Zhang, Jian-Guo; Lew, Andrew M

    2016-01-01

    Plasmacytoid dendritic cells (pDCs) play an important role in immunity to certain pathogens and immunopathology in some autoimmune diseases. They are thought to have a longer lifespan than conventional DCs (cDCs), largely based on a slower rate of BrdU labeling by splenic pDCs. Here we demonstrated that pDC expansion and therefore BrdU labeling by pDCs occurs in bone marrow (BM). The rate of labeling was similar between BM pDCs and spleen cDCs. Therefore, slower BrdU labeling of spleen pDCs likely reflects the "migration time" (∼2 days) for BrdU labeled pDCs to traffic to the spleen, not necessarily reflecting longer life span. Tracking the decay of differentiated DCs showed that splenic pDCs and cDCs decayed at a similar rate. We suggest that spleen pDCs have a shorter in vivo lifespan than estimated utilizing some of the previous approaches. Nevertheless, pDC lifespan varies between mouse strains. pDCs from lupus-prone NZB mice survived longer than C57BL/6 pDCs. We also demonstrated that activation either positively or negatively impacted on the survival of pDCs via different cell-death mechanisms. Thus, pDCs are also short-lived. However, the pDC lifespan is regulated by genetic and environmental factors that may have pathological consequence. PMID:27112985

  16. Impact of short-lived non-CO2 mitigation on carbon budgets for stabilizing global warming

    NASA Astrophysics Data System (ADS)

    Rogelj, Joeri; Meinshausen, Malte; Schaeffer, Michiel; Knutti, Reto; Riahi, Keywan

    2015-07-01

    Limiting global warming to any level requires limiting the total amount of CO2 emissions, or staying within a CO2 budget. Here we assess how emissions from short-lived non-CO2 species like methane, hydrofluorocarbons (HFCs), black-carbon, and sulphates influence these CO2 budgets. Our default case, which assumes mitigation in all sectors and of all gases, results in a CO2 budget between 2011-2100 of 340 PgC for a >66% chance of staying below 2°C, consistent with the assessment of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Extreme variations of air-pollutant emissions from black-carbon and sulphates influence this budget by about ±5%. In the hypothetical case of no methane or HFCs mitigation—which is unlikely when CO2 is stringently reduced—the budgets would be much smaller (40% or up to 60%, respectively). However, assuming very stringent CH4 mitigation as a sensitivity case, CO2 budgets could be 25% higher. A limit on cumulative CO2 emissions remains critical for temperature targets. Even a 25% higher CO2 budget still means peaking global emissions in the next two decades, and achieving net zero CO2 emissions during the third quarter of the 21st century. The leverage we have to affect the CO2 budget by targeting non-CO2 diminishes strongly along with CO2 mitigation, because these are partly linked through economic and technological factors.

  17. Iodine-131: a potential short-lived, wastewater-specific particle tracer in an urbanized estuarine system.

    PubMed

    Smith, Joseph P; Oktay, Sarah I; Kada, John; Olsen, Curtis R

    2008-08-01

    The short-lived, fission-produced radioisotope, 131I (t1/2 = 8.04 days), was detected in wastewater, surficial sediment, and suspended particulate matter (SPM) samples collected from New York Harbor (NYH) between 2001 and 2002. lodine-131 is used as a radiopharmaceutical for medical imaging, diagnostics, and treatments for conditions of the thyroid. It is introduced into the municipal waste stream by medical facilities and patients and is subsequently released into the estuary via wastewater effluent. Measured 131I activities in surface sediments were correlated with those of 7Be (t1/2 = 53.2 days), a naturally occurring radioisotope that is widely used to quantify particle dynamics, sediment focusing, and short-term sediment deposition and accumulation in aquatic systems. Surficial sediment 131I activities were also compared with measured trace metal (Cu, Pb) and organic carbon (OC(sed)) concentrations which can be linked to wastewater inputs. These preliminary results from NYH introduce 131I as a potentially valuable source-specific, shortlived biogeochemical tracer (timescales < 1 month) for particles, sediments, and wastewater-sourced contaminants in urbanized aquatic systems. PMID:18754457

  18. Mesenchymal stem cells are short-lived and do not migrate beyond the lungs after intravenous infusion

    PubMed Central

    Eggenhofer, E.; Benseler, V.; Kroemer, A.; Popp, F. C.; Geissler, E. K.; Schlitt, H. J.; Baan, C. C.; Dahlke, M. H.; Hoogduijn, M. J.

    2012-01-01

    Mesenchymal stem cells (MSC) are under investigation as a therapy for a variety of disorders. Although animal models show long term regenerative and immunomodulatory effects of MSC, the fate of MSC after infusion remains to be elucidated. In the present study the localization and viability of MSC was examined by isolation and re-culture of intravenously infused MSC. C57BL/6 MSC (500,000) constitutively expressing DsRed-fluorescent protein and radioactively labeled with Cr-51 were infused via the tail vein in wild-type C57BL/6 mice. After 5 min, 1, 24, or 72 h, mice were sacrificed and blood, lungs, liver, spleen, kidneys, and bone marrow removed. One hour after MSC infusion the majority of Cr-51 was found in the lungs, whereas after 24 h Cr-51 was mainly found in the liver. Tissue cultures demonstrated that viable donor MSC were present in the lungs up to 24 h after infusion, after which they disappeared. No viable MSC were found in the other organs examined at any time. The induction of ischemia-reperfusion injury in the liver did not trigger the migration of viable MSC to the liver. These results demonstrate that MSC are short-lived after i.v. infusion and that viable MSC do not pass the lungs. Cell debris may be transported to the liver. Long term immunomodulatory and regenerative effects of infused MSC must therefore be mediated via other cell types. PMID:23056000

  19. Developmentally regulated instability of the GPI-PLC mRNA is dependent on a short-lived protein factor

    PubMed Central

    Webb, Helena; Burns, Roisin; Ellis, Louise; Kimblin, Nicola; Carrington, Mark

    2005-01-01

    The expression of the vast majority of protein coding genes in trypanosomes is regulated exclusively at the post-transcriptional level. Developmentally regulated mRNAs that vary in levels of expression have provided an insight into one mechanism of regulation; a decrease in abundance is due to a shortened mRNA half-life. The decrease in half-life involves cis-acting elements in the 3′ untranslated region of the mRNA. The trans-acting factors necessary for the increased rate of degradation remain uncharacterized. The GPI-PLC gene in Trypanosoma brucei encodes a phospholipase C expressed in mammalian bloodstream form, but not in the insect procyclic form. Here, it is reported that the differential expression of the GPI-PLC mRNA also results from a 10-fold difference in half-life. Second, the instability of the GPI-PLC mRNA in procyclic forms can be reversed by the inhibition of protein synthesis. Third, specifically blocking the translation of the GPI-PLC mRNA in procyclic forms by the inclusion of a hairpin in the 5′ untranslated region does not result in stabilization of the mRNA. Thus, the effect of protein synthesis inhibitors in stabilizing the GPI-PLC mRNA operates in trans through a short-lived factor dependent on protein synthesis. PMID:15755751

  20. Analysis of very short-lived halocarbons in the ocean and atmosphere using fully automated sampling techniques

    NASA Astrophysics Data System (ADS)

    Andrews, S. J.; Carpenter, L. J.

    2012-04-01

    Reactive halogen species, originating in part from very short-lived halocarbons (VSLH), play an important role in tropospheric chemistry. However, VSLH datasets are sparse compared to those of other important trace gases. In addition, calibration is non-trivial and a lack of a common scale limits their usefulness. A new, fully automated seawater analysis instrument was developed to provide near-continuous surface seawater measurements and semi-automated CTD measurements of VSLH. This instrument was deployed, alongside a new system for continuous on-line air measurements, during the Tropical Ocean tRoposphere Experiment of Reactive halogen species and OVOCs (TORERO) cruise. High frequency online air measurements, automated seawater measurements and simultaneous chlorophyll-α fluorescence will be reported for the duration of the cruise. The data will compliment VSLH measurements taken from onboard the NCAR G-V HIAPER aircraft to provide a comprehensive vertical profile from deep ocean to upper troposphere. Inter-comparison of standard gases used during the campaign will add confidence to results and link this data set with recent inter-comparisons in the UK and US.

  1. Constraints on the Origin of Chondrules and CAIs from Short-Lived and Long-Lived Radionuclides

    SciTech Connect

    Kita, N T; Huss, G R; Tachibana, S; Amelin, Y; Nyquist, L E; Hutcheon, I D

    2005-10-24

    The high time resolution Pb-Pb ages and short-lived nuclide based relative ages for CAIs and chondrules are reviewed. The solar system started at 4567.2 {+-} 0.6Ma inferred from the high precision Pb-Pb ages of CAIs. Time scales of CAIs ({le}0.1Myr), chondrules (1-3Myr), and early asteroidal differentiation ({ge}3Myr) inferred from {sup 26}Al relative ages are comparable to the time scale estimated from astronomical observations of young star; proto star, classical T Tauri star and week-lined T Tauri star, respectively. Pb-Pb ages of chondrules also indicate chondrule formation occur within 1-3 Myr after CAIs. Mn-Cr isochron ages of chondrules are similar to or within 2 Myr after CAI formation. Chondrules from different classes of chondrites show the same range of {sup 26}Al ages in spite of their different oxygen isotopes, indicating that chondrule formed in the localized environment. The {sup 26}Al ages of chondrules in each chondrite class show a hint of correlation with their chemical compositions, which implies the process of elemental fractionation during chondrule formation events.

  2. Ozone Destruction in the Upper Troposphere/Lower Stratosphere from Short-Lived Halogens and Climate Impacts

    NASA Astrophysics Data System (ADS)

    Hossaini, Ryan; Chipperfield, Martyn; Montzka, Stephen; Rap, Alex; Dhomse, Sandip; Feng, Wuhu

    2014-05-01

    Halogens released from very short-lived substances (VSLS) can deplete ozone in the upper-troposphere and lower stratosphere where the perturbation can exert a large climate impact. In addition to the known ozone loss from natural biogenic bromine VSLS, such as bromoform (CHBr3), using a global atmospheric model we show that anthropogenic chlorine VSLS such as dichloromethane (CH2Cl2) - not regulated by the Montreal Protocol - also contribute. Although this impact is small compared to bromine VSLS at present, CH2Cl2 has industrial sources and observations show its atmospheric loading is increasing rapidly. We estimate a significant radiative effect of the bromine and chlorine VSLS-driven lower stratospheric ozone destruction of -0.11 Wm-2. The largest impact comes from ozone loss at high latitudes, where column ozone decreases due to VSLS are up to 6%. The trend in anthropogenic chlorine VSLS could cause a significant radiative forcing, especially if augmented by any trend in natural bromine VSLS. We also used the model to study the impact of iodine-containing VSLS such as methyl iodide (CH3I). Of the three halogens iodine has the largest leverage to destroy lower stratospheric ozone, but current limits based on IO observations indicate only a minor impact at present.

  3. Short-lived Radium Isotopes in the Hawaiian Margin: Evidence for Large Fluid Fluxes Through the Puna Ridge

    NASA Astrophysics Data System (ADS)

    Moore, W. S.; Paull, C. K.; Ussler, W.

    2001-12-01

    Techniques to sample and measure short-lived radium isotopes have significantly advanced understanding of groundwater-seawater exchange in coastal areas. The established sampling protocol utilizes traditional wire-line samplers from surface vessels to recover large (200 L) seawater samples. These samples are subsequently passed through Mn-fiber columns at a slow rate (100 L per hour) to assure high radium stripping efficiency. But, sampling near-bottom waters in areas of complicated bathymetry represents a technical challenge for traditional wire-line water sampling equipment. For MBARI's 2001 Hawaii expedition, we built a simple sampler to extract Ra from seawater surrounding the ROV Tiburon. The system uses a variable-flow electric pump to provide 1-2 L/min flow through one of 12 Mn-fiber-filled Ra-stripping canisters mounted on the ROV Tiburon. Values allow the flow to be directed to specific canisters. A flow meter allows the operator to control the flow and compute the volume sampled. The fibers are counted shipboard shortly after vehicle recovery. The ROV proved to be an ideal platform for Ra-sampling because it is able to slowly pump considerable volumes of seawater through the Ra-stripping columns while maintaining close contact with the bottom. Because the manifold was mounted on the ROV's side arm, its interference with other research objectives was minimal. Most of our sampling in Hawaii was conducted as a piggyback effort. We were able to collect 167 radium samples on 37 ROV dives with an average of 206 liters of seawater passing through the stripping canisters. Moreover, we are confident that the sampled waters come from 1-3 above the bottom. We measured significant activities of short-lived radium isotopes, 223Ra (half-life = 11 days) and 224Ra (half-life = 3.7 days), around the margins of the Hawaiian Islands to depths of 3100 m. These measurements suggest numerous groundwater or pore fluid inputs to the surrounding ocean. In general 223Ra activities were considerably greater than 224Ra in spite of the expected higher production rate of 224Ra from basalt. 223Ra was not supported by dissolved 227Ac. The highest enrichments of 223Ra were measured over the Puna Ridge (2100 m depth) east of Hawaii. Here 223Ra activities reached 2 dpm/100L, similar to activities measured near sites of active submarine groundwater discharge in the South Atlantic Bight. The high 223Ra values were not associated with significant thermal anomalies. To explain the high activities of 223Ra unaccompanied by 224Ra, we postulate that thermally-driven circulation of sea water through the Puna Ridge deposits 231Pa on basalt surfaces. With time the 231Pa produces 227Ac and 223Ra, which desorbs into circulating fluids. These fluids then transport 223Ra into the overlying ocean. Based on the inventory of 223Ra above the Puna Ridge, we estimate the flow of fluids through the ridge to be on the order of 40cm3cm-2day-1. In less than 100 years the incoming seawater could provide enough 231Pa to basalt surfaces to balance the inventory of 223Ra above the ridge if all of the 223Ra was transported to the overlying water. These observations have significant implications for quantifying fluid fluxes from the flanks of the mid ocean ridge. By mapping 223Ra inventories in the ocean above ridge flanks and the activity of 223Ra in the emerging fluids, the fluid flux can be obtained. These measurements could help resolve the debate of the relative importance of high and low temperature venting from the ridge.

  4. Effect of Drive Cycle and Gasoline Particulate Filter on the Size and Morphology of Soot Particles Emitted from a Gasoline-Direct-Injection Vehicle.

    PubMed

    Saffaripour, Meghdad; Chan, Tak W; Liu, Fengshan; Thomson, Kevin A; Smallwood, Gregory J; Kubsh, Joseph; Brezny, Rasto

    2015-10-01

    The size and morphology of particulate matter emitted from a light-duty gasoline-direct-injection (GDI) vehicle, over the FTP-75 and US06 transient drive cycles, have been characterized by transmission-electron-microscope (TEM) image analysis. To investigate the impact of gasoline particulate filters on particulate-matter emission, the results for the stock-GDI vehicle, that is, the vehicle in its original configuration, have been compared to the results for the same vehicle equipped with a catalyzed gasoline particulate filter (GPF). The stock-GDI vehicle emits graphitized fractal-like aggregates over all driving conditions. The mean projected area-equivalent diameter of these aggregates is in the 78.4-88.4 nm range and the mean diameter of primary particles varies between 24.6 and 26.6 nm. Post-GPF particles emitted over the US06 cycle appear to have an amorphous structure, and a large number of nucleation-mode particles, depicted as low-contrast ultrafine droplets, are observed in TEM images. This indicates the emission of a substantial amount of semivolatile material during the US06 cycle, most likely generated by the incomplete combustion of accumulated soot in the GPF during regeneration. The size of primary particles and soot aggregates does not vary significantly by implementing the GPF over the FTP-75 cycle; however, particles emitted by the GPF-equipped vehicle over the US06 cycle are about 20% larger than those emitted by the stock-GDI vehicle. This may be attributed to condensation of large amounts of organic material on soot aggregates. High-contrast spots, most likely solid nonvolatile cores, are observed within many of the nucleation-mode particles emitted over the US06 cycle by the GPF-equipped vehicle. These cores are either generated inside the engine or depict incipient soot particles which are partially carbonized in the exhaust line. The effect of drive cycle and the GPF on the fractal parameters of particles, such as fractal dimension and fractal prefactor, is insignificant. PMID:26340691

  5. Recent Measurements of Groundwater Recharge and Discharge Through Everglades' Peat Sediments Using Short-Lived Radium Isotopes

    NASA Astrophysics Data System (ADS)

    Krest, J. M.; Harvey, J. W.

    2002-05-01

    Peat sediments are present as a nearly continuous surface layer across large areas of the Everglades. These sediments have relatively low hydraulic conductivity, impeding water exchange between surface water and the underlying surficial aquifer. Although vertical water transport does occur across the peat layer, rates are slow enough that they are difficult to quantify. Even modest rates of vertical transport, however, become significant to water budgets and nutrient cycles when they occur over a large area. In the Everglades, common methods for measuring exchange across the peat layer are prone to complications: small hydraulic gradients are difficult to measure; seepage meters tend to be imprecise at slow rates; radon profiles or emanation rates are complicated by methane bubble ebullition; chloride profiles often exhibit a strong gradient only at the surface of the peat. We are employing a method that takes advantage of the different production rates of short-lived radium isotopes (Ra-223 and Ra-224) in the peat sediments and in the underlying sand or carbonate aquifer. Pore water radium concentrations are balanced by radioactive decay and production in the surrounding sediments. As the pore water is carried across the sediment interface a temporary excess or deficit of dissolved radium exists until decay is again balanced by the new production rate. We have derived steady-state, one-dimensional models to determine flow rates on the basis of this disequilibrium. This method has the advantage of being most sensitive at the base of the peat, away from transient perturbations occurring at the surface. In addition, Ra-223 and Ra-224 are collected simultaneously, providing two independent measurements. At present we have tested the method in Water Conservation Area-1 and WCA-2A, quantifying recharge and discharge on opposite sides of Levee 39, and also in more central sites in WCA-2A. Additional work is underway in Taylor Slough and Shark Slough.

  6. Starbursts and high-redshift galaxies are radioactive: high abundances of 26Al and other short-lived radionuclides

    NASA Astrophysics Data System (ADS)

    Lacki, Brian C.

    2014-06-01

    Short-lived radionuclides (SLRs) like 26Al are synthesized by massive stars and are a byproduct of star formation. The abundances of SLRs in the gas of a star-forming galaxy are inversely proportional to the gas consumption time. The rapid evolution of specific star formation rate (SSFR) of normal galaxies implies they had mean SLR abundances 3-10 times higher at z = 2. During the epoch of Solar system formation, the background SLR abundances of the Galaxy were up to twice as high as at present, if SLR yields from massive stars do not depend on metallicity. If SLRs are homogenized in the gas of galaxies, the high SSFRs of normal galaxies can partly explain the elevated abundance of SLRs like 60Fe and 26Al in the early Solar system. Starburst galaxies have much higher SSFRs still, and have enormous mean abundances of 26Al (26Al/27Al ?10-3 for solar metallicity gas). The main uncertainty is whether the SLRs are mixed with the star-forming molecular gas: they could be trapped in hot gas and decay before entering the colder phases, or be blown out by starburst winds. I consider how variability in star formation rate affects the SLR abundances, and I discuss how SLR transport may differ in these galaxies. The enhanced 26Al of starbursts might maintain moderate ionization rates (10-18-10-17 s-1), possibly dominating ionization in dense clouds not penetrated by cosmic rays. Similar ionization rates would be maintained in protoplanetary discs of starbursts, if the SLRs are well mixed, and the radiogenic heating of planetesimals would likewise be much higher. In this way, galaxy evolution can affect the geological history of planetary systems.

  7. PTF10iya: a short-lived, luminous flare from the nuclear region of a star-forming galaxy

    NASA Astrophysics Data System (ADS)

    Cenko, S. Bradley; Bloom, Joshua S.; Kulkarni, S. R.; Strubbe, Linda E.; Miller, Adam A.; Butler, Nathaniel R.; Quimby, Robert M.; Gal-Yam, Avishay; Ofek, Eran O.; Quataert, Eliot; Bildsten, Lars; Poznanski, Dovi; Perley, Daniel A.; Morgan, Adam N.; Filippenko, Alexei V.; Frail, Dale A.; Arcavi, Iair; Ben-Ami, Sagi; Cucchiara, Antonio; Fassnacht, Christopher D.; Green, Yoav; Hook, Isobel M.; Howell, D. Andrew; Lagattuta, David J.; Law, Nicholas M.; Kasliwal, Mansi M.; Nugent, Peter E.; Silverman, Jeffrey M.; Sullivan, Mark; Tendulkar, Shriharsh P.; Yaron, Ofer

    2012-03-01

    We present the discovery and characterization of PTF10iya, a short-lived (Δt≈ 10 d, with an optical decay rate of ˜0.3 mag d-1), luminous (? mag) transient source found by the Palomar Transient Factory. The ultraviolet/optical spectral energy distribution is reasonably well fitted by a blackbody with T≈ (1-2) × 104 K and peak bolometric luminosity LBB≈ (1-5) × 1044 erg s-1 (depending on the details of the extinction correction). A comparable amount of energy is radiated in the X-ray band that appears to result from a distinct physical process. The location of PTF10iya is consistent with the nucleus of a star-forming galaxy (z= 0.224 05 ± 0.000 06) to within 350 mas (99.7 per cent confidence radius), or a projected distance of less than 1.2 kpc. At first glance, these properties appear reminiscent of the characteristic 'big blue bump' seen in the near-ultraviolet spectra of many active galactic nuclei (AGNs). However, emission-line diagnostics of the host galaxy, along with a historical light curve extending back to 2007, show no evidence for AGN-like activity. We therefore consider whether the tidal disruption of a star by an otherwise quiescent supermassive black hole may account for our observations. Though with limited temporal information, PTF10iya appears broadly consistent with the predictions for the early 'super-Eddington' phase of a solar-type star being disrupted by a ˜107 M⊙ black hole. Regardless of the precise physical origin of the accreting material, the large luminosity and short duration suggest that otherwise quiescent galaxies can transition extremely rapidly to radiate near the Eddington limit; many such outbursts may have been missed by previous surveys lacking sufficient cadence.

  8. Automated system for neutron activation analysis determination of short lived isotopes at The DOW Chemical Company's TRIGA research reactor

    NASA Astrophysics Data System (ADS)

    Zieman, J. J.; Rigot, W. L.; Romick, J. D.; Quinn, T. J.; Kocher, C. W.

    1994-12-01

    An automated neutron activation analysis (NAA) system for the determination of short lived isotopes was constructed at The DOW Chemical Company's TRIGA Research Reactor in 1993. The NAA group of the Analytical Sciences Laboratory uses the reactor for thousands of analyses each year and therefore automation is important to achieve and maintain high throughput and precision (productivity). This project is complementary to automation of the long-lived counting facilities (see Romick et al., these Proceedings). Canberra/Nuclear Data Systems DEC-based software and electronics modules and an I/O mounting board are the basic commercial components. A Fortran program on a VAX computer controls I/O via ethernet to an Acquisition Interface Module (AIM). The AIM controls the γ spectrometer modules and is interfaced to a Remote Parallel Interface (RPI) module which controls the pneumatic transfer apparatus with TTL signals to the I/O mounting board. Near-infrared sensors are used to monitor key points in the transfer system. Spectra are acquired by a single HPGe detector mounted on a sliding rail to allow flexible and more reproducible counting geometries than with manual sample handling. The maximum sample size is 8 ml in a heat-sealed two dram vial. The sample vial is nested into a "rabbit" vial for irradiation which can be automatically removed prior to spectrum collection. The system was designed to be used by the reactor operator at the control console without the aid of an additional experimenter. Applications include the determination of selenium and silver in coal and water, fluorine in tetra-fluoro ethylene (TFE) coated membranes, aluminum and titanium in composite materials and trace fluorine in non-chlorinated cleaning solvents. Variable dead time software allows analysis for 77mSe despite high dead times from 16N encountered in samples.

  9. ICV-Transplanted Human Glial Precursor Cells Are Short-Lived Yet Exert Immunomodulatory Effects in Mice with EAE

    PubMed Central

    KIM, HEECHUL; WALCZAK, PIOTR; MUJA, NASER; CAMPANELLI, JAMES T.; BULTE, JEFF W. M.

    2013-01-01

    Human glial precursor cells (hGPs) have potential for remyelinating lesions and are an attractive cell source for cell therapy of multiple sclerosis (MS). To investigate whether transplanted hGPs can affect the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of MS, we evaluated the therapeutic effects of transplanted hGPs together with the in vivo fate of these cells using magnetic resonance imaging (MRI) and bioluminescence imaging (BLI). At 14 days post-EAE induction, mice (n = 19) were intracerebroventricularly (ICV) injected with 5 × 105 hGPs that were magnetically labeled with superparamagnetic iron oxide (SPIO) particles as MR contrast agent and transduced with firefly luciferase for BLI of cell survival. Control mice (n = 18) received phosphate buffered saline (PBS) vehicle only. The severity of EAE clinical disability in the hGP-transplanted group was significantly suppressed (P < 0.05) with concomitant inhibition of ConA and MOG-specific T cell proliferation in the spleen. Astrogliosis was reduced and a lower activity of macrophages and/or microglia was observed in the spinal cord (P < 0.05). On MRI, SPIO signal was detected within the lateral ventricle from 1 day post-transplantation and remained there for up to 34 days. BLI indicated that most cells did not survive beyond 5–10 days, consistent with the lack of detectable migration into the brain parenchyma and the histological presence of an abundance of apoptotic cells. Transplanted hGPs could not be detected in the spleen. We conclude that ICV transplantation of short-lived hGPs can have a remote therapeutic effect through immunomodulation from within the ventricle, without cells directly participating in remyelination. PMID:22499166

  10. How sensitive is the recovery of stratospheric ozone to changes in concentrations of very short-lived bromocarbons?

    NASA Astrophysics Data System (ADS)

    Yang, X.; Abraham, N. L.; Archibald, A. T.; Braesicke, P.; Keeble, J.; Telford, P. J.; Warwick, N. J.; Pyle, J. A.

    2014-10-01

    Naturally produced very short-lived substances (VSLS) account for almost a quarter of the current stratospheric inorganic bromine, Bry. Following VSLS oxidation, bromine radicals (Br and BrO) can catalytically destroy ozone. The extent to which possible increases in surface emissions or transport of these VSLS bromocarbons to the stratosphere could counteract the effect of halogen reductions under the Montreal Protocol is an important policy question. Here, by using a chemistry-climate model, UM-UKCA, we investigate the impact of a hypothetical doubling (an increase of 5 ppt Bry) of VSLS bromocarbons on ozone and how the resulting ozone changes depend on the background concentrations of chlorine and bromine. Our model experiments indicate that for the 5 ppt increase in Bry from VSLS, the ozone decrease in the lowermost stratosphere of the Southern Hemisphere (SH) may reach up to 10% in the annual mean; the ozone decrease in the Northern Hemisphere (NH) is smaller (4-6%). The largest impact on the ozone column is found in the Antarctic spring. There is a significantly larger ozone decrease following the doubling of the VSLS burden under a high stratospheric chlorine background than under a low chlorine background, indicating the importance of the inter-halogen reactions. For example, the decline in the high-latitude, lower-stratospheric ozone concentration as a function of Bry is higher by about 30-40% when stratospheric Cly is ~ 3 ppb (present day), compared with Cly of ~ 0.8 ppb (a pre-industrial or projected future situation). Bromine will play an important role in the future ozone layer. However, even if bromine levels from natural VSLS were to increase significantly later this century, changes in the concentration of ozone will likely be dominated by the decrease in anthropogenic chlorine. Our calculation suggests that for a 5 ppt increase in Bry from VSLS, the Antarctic ozone hole recovery date could be delayed by approximately 6-8 years, depending on Cly levels.

  11. How sensitive is the recovery of stratospheric ozone to changes in concentrations of very short lived bromocarbons?

    NASA Astrophysics Data System (ADS)

    Yang, X.; Abraham, N. L.; Archibald, A. T.; Braesicke, P.; Keeble, J.; Telford, P.; Warwick, N. J.; Pyle, J. A.

    2014-04-01

    Naturally produced very short-lived substances (VSLS), like bromocarbons, account for almost a quarter of the current stratospheric inorganic bromine, Bry. Following VSLS oxidation, bromine radicals (Br and BrO) can catalytically destroy ozone. The extent to which possible increases in surface emissions or transport of these VSLS bromocarbons to the stratosphere could counteract the effect of halogen reductions under the Montreal Protocol is an important policy question. Here by using a chemistry-climate model, UM-UKCA, we investigate the impact of a hypothetical increase in VSLS on ozone and how that impact depends on the background concentrations of chlorine and bromine. Our model experiments indicate that for a ~5 ppt increase in Bry from VSLS, the local ozone loss in the lowermost stratosphere of the Southern Hemisphere (SH) may reach up to 10% in the annual mean; the ozone loss in the Northern Hemisphere (NH) is smaller (4-6%). There is more ozone loss following an increase in VSLS burden under a high stratospheric chlorine background than under a low chlorine background indicating the importance of the inter-halogen reactions. For example, the rate of decline of the stratospheric ozone concentration as a function of Bry is higher by about 30-40% when stratospheric Cly is ~3 ppb (present day) compared with Cly of ~0.8 ppb (apre-industrial or projected future situation). Although bromine plays an important role in destroying ozone, inorganic chlorine is the dominant halogen compound. Even if bromine levels from natural VSLS were to increase significantly later this century, changes in the concentration of ozone will be dominated by the recovery of anthropogenic chlorine. Our calculation suggests that for a 5 ppt increase in Bry from VSLS, the Antarctic ozone hole recover date could be delayed by approximately 7 years.

  12. Short-lived halocarbons efficient at influencing climate through ozone loss in the upper troposphere-lower stratosphere

    NASA Astrophysics Data System (ADS)

    Hossaini, Ryan; Chipperfield, Martyn; Montzka, Steven; Rap, Alex; Dhomse, Sandip; Feng, Wuhu

    2015-04-01

    Halogenated very short-lived substances (VSLS) of both natural and anthropogenic origin are a significant source of atmospheric bromine, chlorine and iodine. Due to relatively short atmospheric lifetimes (typically <6 months), VSLS breakdown in the upper troposphere-lower stratosphere (UTLS), where ozone perturbations drive a disproportionately large climate impact compared to other altitudes. Here we present chemical transport model simulations that quantify VSLS-driven ozone loss in the UTLS and infer the climate relevance of these ozone perturbations using a radiative transfer model. Our results indicate that through their impact on UTLS ozone, VSLS are efficient at influencing climate. We calculate a whole atmosphere global mean radiative effect (RE) of -0.20 (-0.16 to -0.23) Wm-2 from natural and anthropogenic VSLS-driven ozone loss, including a tropospheric contribution of -0.12 Wm-2. In the stratosphere, the RE due to ozone loss from natural bromine-containing VSLS (e.g. CHBr3, CH2Br2) is almost half of that from long-lived anthropogenic compounds (e.g. CFCs) and normalized by equivalent chlorine is ~4 times larger. We show that the anthropogenic chlorine-containing VSLS, not regulated by the Montreal Protocol, also contribute to ozone loss in the UTLS and that the atmospheric concentration of dichloromethane (CH2Cl2), the most abundant of these, is increasing rapidly. Finally, we present evidence that VSLS have made a small yet previously unrecognized contribution to the ozone-driven radiative forcing of climate since pre-industrial times of -0.02 (-0.01 to -0.03) Wm-2. Given the climate leverage that VSLS possess, future increases to their emissions, either through continued industrial or altered natural processes, may be important for future climate forcing.

  13. A High-Throughput Screen for Alpha Particle Radiation Protectants

    PubMed Central

    Seideman, Jonathan H.; Shum, David; Djaballah, Hakim

    2010-01-01

    Abstract Alpha-particle-emitting elements are of increasing importance as environmental and occupational carcinogens, toxic components of radiation dispersal devices and accidents, and potent therapeutics in oncology. Alpha particle radiation differs from radiations of lower linear energy transfer in that it predominantly damages DNA via direct action. Because of this, radical scavengers effective for other radiations have had only limited effect in mitigating alpha particle toxicity. We describe here a simple assay and a pilot screen of 3,119 compounds in a high-throughput screen (HTS), using the alpha-particle-emitting isotope, 225Ac, for the discovery of compounds that might protect mammalian cells from alpha particles through novel mechanisms. The assay, which monitored the viability of a myeloid leukemic cell line upon alpha particle exposure, was robust and reproducible, yielding a Z' factor of 0.66 and a signal-to-noise ratio of nearly 10 to 1. Surprisingly, 1 compound emerged from this screen, epoxy-4,5-?-dihydroxysantonin (EDHS), that showed considerable protective activity. While the value of EDHS remains to be determined, its discovery is a proof of concept and validation of the utility of this HTS methodology. Further application of the described assay could yield compounds useful in minimizing the toxicity and carcinogenesis associated with alpha particle exposure. PMID:20658946

  14. The ATM kinase signaling induced by the low-energy β-particles emitted by (33)P is essential for the suppression of chromosome aberrations and is greater than that induced by the energetic β-particles emitted by (32)P.

    PubMed

    White, Jason S; Yue, Ning; Hu, Jing; Bakkenist, Christopher J

    2011-03-15

    Ataxia-telangiectasia mutated (ATM) encodes a nuclear serine/threonine protein kinase whose activity is increased in cells exposed to low doses of ionizing radiation (IR). Here we examine ATM kinase activation in cells exposed to either (32)P- or (33)P-orthophosphate under conditions typically employed in metabolic labelling experiments. We calculate that the absorbed dose of IR delivered to a 5cm×5cm monolayer of cells incubated in 2ml media containing 1mCi of the high-energy (1.70MeV) β-particle emitter (32)P-orthophosphate for 30min is ∼1Gy IR. The absorbed dose of IR following an otherwise identical exposure to the low-energy (0.24MeV) β-particle emitter (33)P-orthophosphate is ∼0.18Gy IR. We show that low-energy β-particles emitted by (33)P induce a greater number of ionizing radiation-induced foci (IRIF) and greater ATM kinase signaling than energetic β-particles emitted by (32)P. Hence, we demonstrate that it is inappropriate to use (33)P-orthophosphate as a negative control for (32)P-orthophosphate in experiments investigating DNA damage responses to DNA double-strand breaks (DSBs). Significantly, we show that ATM accumulates in the chromatin fraction when ATM kinase activity is inhibited during exposure to either radionuclide. Finally, we also show that chromosome aberrations accumulate in cells when ATM kinase activity is inhibited during exposure to ∼0.36Gy β-particles emitted by (33)P. We therefore propose that direct cellular exposure to (33)P-orthophosphate is an excellent means to induce and label the IR-induced, ATM kinase-dependent phosphoproteome. PMID:21315088

  15. Application of mass spectrometric techniques for the trace analysis of short-lived iodine-containing volatiles emitted by seaweed.

    PubMed

    Kundel, Michael; Thorenz, Ute R; Petersen, Jan H; Huang, Ru-Jin; Bings, Nicolas H; Hoffmann, Thorsten

    2012-04-01

    Knowledge of the composition and emission rates of iodine-containing volatiles from major widespread seaweed species is important for modeling the impact of halogens on gas-phase atmospheric chemistry, new particle formation, and climate. In this work, we present the application of mass spectrometric techniques for the quantification of short-lived iodine-containing volatiles emitted by eight different seaweeds from the intertidal zone of Helgoland, Germany. A previously developed online time-of-flight aerosol mass spectrometric method was used to determine I(2) emission rates and investigate temporally resolved emission profiles. Simultaneously, iodocarbons were preconcentrated on solid adsorbent tubes and quantified offline using thermodesorption-gas chromatography-mass spectrometry. The total iodine content of the seaweeds was determined using microwave-assisted tetramethylammonium hydroxide extraction followed by inductively coupled-plasma mass spectrometry analysis. The highest total iodine content was found in the Laminariales, followed by the brown algae Ascophyllum nodosum, Fucus vesiculosus, Fucus serratus, and both red algae Chondrus crispus and Delesseria sanguinea. Laminariales were found to be the strongest I(2) emitters. Time series of the iodine release of Laminaria digitata and Laminaria hyperborea showed a strong initial I(2) emission when first exposed to air followed by an exponential decline of the release rate. For both species, I(2) emission bursts were observed. For Laminaria saccharina und F. serratus, a more continuous I(2) release profile was detected, however, F. serratus released much less I(2). A. nodosum and F. vesiculosus showed a completely different emission behavior. The I(2) emission rates of these species were slowly increasing with time during the first 1 to 2 h until a more or less stable I(2) emission rate was reached. The lowest I(2) emission rates were detected for the red algae C. crispus and D. sanguinea. Total iodocarbon emission rates showed almost the same general trend, however, the total iodocarbon emission rates were about one to two orders of magnitude lower than those of molecular iodine, demonstrating that I(2) is the major iodine containing volatile released by the investigated seaweed species. In addition, a clear dependency of iodocarbon emission from the ozone level (0-150 ppb O(3)) was found for L. digitata. PMID:22227744

  16. On the Relation between Stratospheric Chlorine/Bromine Loading and Short-Lived Tropospheric Source Gases. Appendix D

    NASA Technical Reports Server (NTRS)

    Ko, Malcolm K. W.; Sze, Nien-Dak; Scott, Courtney J.; Weisenstein, Debra K.

    1997-01-01

    Current methods for estimating the concentrations of inorganic chlorine/bromine species Cl(y)/Br(y) in the stratosphere due to decomposition of tropospheric source gases assume that the Cl(y)/Br(y) concentration in the stratosphere is determined mainly by the balance between production from in situ oxidation of the source gases in the stratosphere and removal by transport of Cl(y)/Br(y) out of the stratosphere. The rationale being that for source gases whose lifetimes are of the order of several months or longer the concentration of Cl(y)/Br(y) in the troposphere is small because they are produced at a relatively slow rate and also removed efficiently by washout processes. As a result of the small concentration, the rate at which Cl(y)/Br(y) is transported to the stratosphere is expected to be small compared to the in situ stratospheric production. Thus the transport of Cl(y)/Br(y) from the troposphere contributes little to the stratospheric concentration. In contrast, the origin of stratospheric Cl(y)/Br(y) from reactive source gases with tropospheric lifetimes comparable to the washout lifetime of Cl(y)/Br(y) (of the order of 10-30 days) in the troposphere is distinctly different. The in situ source in the stratosphere is expected to be significantly smaller because only a small portion of the source gas is expected to survive the troposphere to be transported into this region. At the same time these short-lived source gases produce appreciable amounts of Cl(y)/Br(y) in the troposphere such that transport to the stratosphere offers a larger source for stratospheric Cl(y)/Br(y) than in situ production. Thus, for reactive source species, simple methods of estimating the concentration of stratospheric Cl(y)/Br(y) that ignore the tropospheric contribution will seriously underestimate the loading. Therefore estimation of the stratospheric Cl(y)/Br(y) loading requires not only measurements of tropospheric source gases but also measurements of Cl(y)/Br(y) at the tropopause. This paper illustrates the mechanism by using results from a two-dimensional chemistry-transport model. However, in view of the importance of tropospheric transport on stratospheric loading the detailed values should be further evaluated using a three-dimensional model with appropriate treatment of convective transport.

  17. Short-lived tectonic switch mechanism for long-term pulses of volcanic activity after mega-thrust earthquakes

    NASA Astrophysics Data System (ADS)

    Lupi, M.; Miller, S. A.

    2014-01-01

    Eruptive rates in volcanic arcs increase significantly after subduction mega-thrust earthquakes. Over short to intermediate time periods the link between mega-thrust earthquakes and arc response can be attributed to dynamic triggering processes or static stress changes, but a fundamental mechanism that controls long-term pulses of volcanic activity after mega-thrust earthquakes has not been proposed yet. Using geomechanical, geological, and geophysical arguments, we propose that increased eruption rates over longer timescales are due to the relaxation of the compressional regime that accompanies mega-thrust subduction zone earthquakes. More specifically, the reduction of the horizontal stress σh promotes the occurrence of short-lived strike-slip kinematics rather than reverse faulting in the volcanic arc. The relaxation of the pre-earthquake compressional regime facilitates magma mobilisation by providing a short-circuit pathway to shallow depths by significantly increasing the hydraulic properties of the system. The timescale for the onset of strike-slip faulting depends on the degree of shear stress accumulated in the arc during inter-seismic periods, which in turn is connected to the degree of strain-partitioning at convergent margins. We performed Coulomb stress transfer analysis to determine the order of magnitude of the stress perturbations in present-day volcanic arcs in response to five recent mega-thrust earthquakes; the 2005 M8.6, 2007 M8.5, and 2007 M7.9 Sumatra earthquakes; the 2010 M8.8 Maule, Chile earthquake; and the 2011 M9.0 Tohoku, Japan earthquake. We find that all but one the shallow earthquakes that occurred in the arcs of Sumatra, Chile and Japan show a marked lateral component. We suggests that the long-term response of volcanic arcs to subduction zone mega-thrust earthquakes will be manifested as predominantly strike-slip seismic events, and that these future earthquakes may be followed closely by indications of rising magma to shallower depths, e.g. surface inflation and seismic swarms.

  18. Short-lived tectonic switch mechanism for long-term pulses of volcanic activity after mega-thrust earthquakes

    NASA Astrophysics Data System (ADS)

    Lupi, M.; Miller, S. A.

    2013-06-01

    Eruptive rates in volcanic arcs increase significantly after mega-thrust earthquakes in subduction zones. Over short to intermediate time periods the link between mega-thrust earthquakes and arc response can be attributed to dynamic triggering processes or static stress changes, but a fundamental mechanism that controls long-term pulses of volcanic activity after mega-thrust earthquakes has not been proposed yet. Using geomechanical, geological, and geophysical arguments, we propose that increased eruption rates over longer timescales are due to the relaxation of the compressional regime that accompanies mega-thrust subduction zone earthquakes. More specifically, the reduction of the horizontal stress σh promotes the occurrence of short-lived strike-slip kinematics rather than reverse faulting in the volcanic arc. The relaxation of the pre-earthquake compressional regime facilitates magma mobilization by providing a short-circuit pathway to shallow depths by significantly increasing the hydraulic properties of the system. The timescale for the onset of strike-slip faulting depends on the degree of shear stress accumulated in the arc during inter-seismic periods, which in turn is connected to the degree of strain-partitioning at convergent margins. We performed Coulomb stress transfer analysis to determine the order of magnitude of the stress perturbations in present-day volcanic arcs in response to five actual mega-thrust earthquakes; the 2005 M8.6, 2007 M8.5, and 2007 M7.9 Sumatra earthquakes; the 2010 M8.8 Maule, Chile earthquake; and the 2011 M9.0 Tohoku, Japan earthquake. We find that all, but one, the shallow earthquakes that occurred in the arcs of Sumatra, Chile and Japan show a marked lateral component. Our hypothesis suggests that the long-term response of volcanic arcs to subduction zone mega-thrust earthquakes will be manifested as predominantly strike-slip seismic events, and that these future earthquakes will be followed closely by seismic swarms, inflation, and other indications of a rising magma source.

  19. Analysis of Very Short-Lived Halocarbons in the Eastern Tropical Pacific Ocean and Atmosphere using Fully Automated Sampling Techniques

    NASA Astrophysics Data System (ADS)

    Andrews, S. J.; Lidster, R.; Carpenter, L.

    2012-12-01

    Reactive halogen species, originating in part from very short-lived halocarbons (VSLH), play an important role in tropospheric chemistry, in particular their reaction with ozone to form halogen oxides. Oceanic iodocarbon production is believed to be a significant source of IO. Unfortunately, VSLH datasets are sparse compared to those of other important trace gases, especially in oligotrophic oceans and the equatorial Pacific where recent satellite retrievals from SCIAMACHY show elevated levels of iodine oxide in the free troposphere. A new, fully automated purge and trap- thermal desorption system coupled to a GC-MS was developed to provide continuous measurement of VSLH in water sampled from a ship's surface seawater inlet and semi-automated analysis of bottle samples from CTD (Conductivity, Temperature Depth) casts. This instrument was deployed on NOAA vessel Ka'imimoana, alongside a new system for continuous on-line air measurements (TD-GC-MS), during the Tropical Ocean tRoposphere Experiment of Reactive halogen species and OVOCs (TORERO) campaign. High frequency boundary layer and surface seawater measurements are presented here with ocean depth profiling of VSLH along the 110°W TOA buoy line. Owing to the high sample throughput and continuous sampling, photolysis driven processes of iodocarbons in the ocean have been observed which have previously only been predicted in modelling and laboratory studies. Sea-air fluxes have been calculated along the cruise track using corresponding meteorological data from the ship. Extensive, open-ocean VSLH flux data is presented which, for the region of this study, is missing or sparse in the WMO ozone assessment of 2010. Inter-comparison of a standard gas used during the campaign allows the use of a single calibration scale (NOAA GMD) between research groups which adds confidence to the results and allows collation of data from the ship with simultaneous measurements taken on-board the NSF/NCAR G-V aircraft using the NCAR Trace Organic Gas Analyzer (TOGA). The inter-comparison will additionally link these data sets with recent inter-comparisons in the UK and US.

  20. Cooling of highly-charged, short-lived ions for precision mass spectrometry at TRIUMF's Ion Trap for Atomic and Nuclear Science

    NASA Astrophysics Data System (ADS)

    Schultz, B. E.; Chowdhury, U.; Simon, V. V.; Andreoiu, C.; Chaudhuri, A.; Gallant, A. T.; Kwiatkowski, A. A.; Macdonald, T. D.; Simon, M. C.; Dilling, J.; Gwinner, G.

    2013-09-01

    At TRIUMF's Ion Trap for Atomic and Nuclear Science (TITAN), masses of short-lived nuclides are measured accurately and precisely using Penning trap mass spectrometry. The achievable precision is primarily limited by the radioactive lifetime of the nuclides. To boost the precision TITAN has demonstrated that short-lived isotopes can be charge-bred to higher charge states within 10-100 s of ms using an electron beam ion trap. The charge breeding process increases the energy spread of the ions, which in turn affects the precision and the efficiency. A novel cooler Penning trap (CPET) has been developed to trap and cool highly-charged ions using electrons prior to the precision measurement. A discussion of electron cooling and the current status of CPET will be given.

  1. Comment on 'Electron-induced bond breaking at low energies in HCOOH and glycine: The role of very short-lived {sigma}* anion states'

    SciTech Connect

    Rescigno, T. N.; Trevisan, C. S.; Orel, A. E.

    2009-10-15

    Recent model calculations by Gallup et al. [Phys. Rev. A79, 042710 (2009)] suggest that low-energy dissociative electron attachment to formic acid can be explained solely in terms of a very short-lived {sigma}* anion state and that no {sigma}*/{pi}* coupling is required. We argue that this interpretation of the experimental data, which is at odds with our earlier study, is flawed.

  2. Alpha particle emitters in medicine

    SciTech Connect

    Fisher, D.R.

    1989-09-01

    Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 ({sup 211}At) and natural bismuth-212 ({sup 212}Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 ({sup 223}Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs.

  3. Russian policy on methane emissions in the oil and gas sector: A case study in opportunities and challenges in reducing short-lived forcers

    NASA Astrophysics Data System (ADS)

    Evans, Meredydd; Roshchanka, Volha

    2014-08-01

    Methane is a potent greenhouse gas, 21 times as powerful as carbon dioxide in contributing to climate change on a ton-for-ton basis. Methane, along with other short-lived forcers such as black carbon and tropospheric ozone, could play an important role in addressing global climate change. This stems both from their overall effect on climate systems, and from their concentrated impact in the short term. Because reducing emissions of such short-lived pollutants may have a large near-term impact in slowing climate change, the United States and other countries have come together to cooperate under the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants, and other partnerships such as the Global Methane Initiative. For global impact, the success of such partnerships depends on their ability to scale up project-specific emission reductions. This paper assesses options and challenges for scaling based on a case study of Russia's oil and gas sector. We examine the challenges to achieving far-reaching emission reductions, successes of companies to date, how Russia has sought to influence methane emissions through its environmental fine system, and options for helping companies achieve large-scale emission reductions in the future through simpler and clearer incentives.

  4. Asymptotic Giant Branch stars as a source of short-lived radioactive nuclei in the solar nebula

    NASA Technical Reports Server (NTRS)

    Wasserburg, G. J.; Busso, M.; Gallino, R.; Raiteri, C. M.

    1994-01-01

    We carried out a theoretical evaluation of the contribution of Asymptotic Giant Branch (AGB) stars to some short-lived (10(exp 6) less than or equal to Tau-bar less than or equal to 2 x 10(exp 7) yr) isotopes in the Interstellar Medium (ISM) and in the early solar system using stellar model calculations for thermally pulsing evolutionary phases of low-mass stars. The yields of s-process nuclei in the convective He-shell for different neutron exposures tau(sub 0) were obtained, and AGB stars were shown to produce several radioactive nuclei (especially Pd-107, Pb-205, Fe-60, Zr-93, Tc-99, Cs-135, and Hf-182) in diferent amounts. Assuming either contamination of the solar nebula from a single AGB star or models for continuous injection and mixing from many stars into the ISM, we calculate the ratios of radioactive to stable nuclei at the epoch of the Sun's formation. The dilution factor between the AGB ejecta and the early solar system matter is obtained by matching the observed Pd-107/Pd-108 and depends on the value of tau(sub 0). It is found that small masses M(sub He) of He-shell material (10(exp -4)-10(exp -7) solar mass) enriched in s-process nuclei are sufficient to contaminate 1 solar mass of the ISM to produce the Pd-107 found in the early solar system. Predictions are made for all of the other radioactive isotopes. The optimal model to explain several observed radioactive species at different states of the proto-solar nebula involves a single AGB star with a low neutron exposure (tau(sub 0) = 0.03 mbarn(sup -1)) which contaminated the cloud with a dilution factor of M(sub He)/solar mass approximately 1.5 x 10(exp -4). This will also contribute newly synthesized stable s-process nuclei in the amount of approximately 10(exp -4) of their abundances already present in the proto-solar cloud. Variations in the degree of homogenization (approximately 30%) of the injected material may account for some of the small general isotopic anomalies found in meteorites. It is also found that Fe-60 is produced in small but significant quantities that may be sufficient to explain the observations if the time elapsed delta from the contamination of the ISM to the formation of protoplanetary bodies is not higher than delta = 5 x 10(exp 6) yr. If delta is longer, up to 10 x 10(exp 6) yr, this would require the single AGB star to experience enhanced neutron densities (n(sub n) approximately 3 x 10(exp 9)n/cu cm) in the s-processing zone in order to compensate for the branching at Fe-59. The alternative model of long-term continuous ejection of matter from many AGB stars does not appear to match the observations. We also estimate the Al-26 production from the H-shell and find that the Al-26 abundance in the early solar system may be readily explained in a self-consistent manner. Moreover, Al-26 from AGB stars may contribute substantially to the galactic Al-26 gamma-source, while no significant gamma-flux from Co-60 (deriving from Fe-60 decay) is to be expected.

  5. Which radionuclide, carrier molecule and clinical indication for alpha-immunotherapy?

    PubMed

    Guerard, F; Barbet, J; Chatal, J F; Kraeber-Bodere, F; Cherel, M; Haddad, F

    2015-06-01

    Beta-emitting radionuclides are not able to kill isolated tumor cells disseminated in the body, even if a high density of radiolabeled molecules can be targeted at the surface of these cells because the vast majority of emitted electrons deliver their energy outside the targeted cells. Alpha-particle emitting radionuclides may overcome this limitation. It is thus of primary importance to test and validate the radionuclide of choice, the most appropriate carrier molecule and the most promising clinical indication. Four α-particle emitting radionuclides have been or are clinically tested in phase I studies namely 213Bi, 225Ac, 212Pb and 211At. Clinical safety has been documented and encouraging efficacy has been shown for some of them (213Bi and 211At). 211At has been the most studied and could be the most promising radionuclide but 225Ac and 212Pb are also of potential great interest. Any carrier molecule that has been labeled with β-emitting radionuclides could be labeled with alpha particle-emitting radionuclide using, for some of them, the same chelating agents. However, the physical half-life of the radionuclide should match the biological half-life of the radioconjugate or its catabolites. Finally everybody agrees, based on the quite short range of alpha particles, on the fact that the clinical indications for alpha-immunotherapy should be limited to the situation of disseminated minimal residual diseases made of small clusters of malignant cells or isolated tumor cells. PMID:25752501

  6. Species Selection Favors Dispersive Life Histories in Sea Slugs, but Higher Per-Offspring Investment Drives Shifts to Short-Lived Larvae.

    PubMed

    Krug, Patrick J; Vendetti, Jann E; Ellingson, Ryan A; Trowbridge, Cynthia D; Hirano, Yayoi M; Trathen, Danielle Y; Rodriguez, Albert K; Swennen, Cornelis; Wilson, Nerida G; Valdés, Ángel A

    2015-11-01

    For 40 years, paleontological studies of marine gastropods have suggested that species selection favors lineages with short-lived (lecithotrophic) larvae, which are less dispersive than long-lived (planktotrophic) larvae. Although lecithotrophs appeared to speciate more often and accumulate over time in some groups, lecithotrophy also increased extinction rates, and tests for state-dependent diversification were never performed. Molecular phylogenies of diverse groups instead suggested lecithotrophs accumulate without diversifying due to frequent, unidirectional character change. Although lecithotrophy has repeatedly originated in most phyla, no adult trait has been correlated with shifts in larval type. Thus, both the evolutionary origins of lecithotrophy and its consequences for patterns of species richness remain poorly understood. Here, we test hypothesized links between development mode and evolutionary rates using likelihood-based methods and a phylogeny of 202 species of gastropod molluscs in Sacoglossa, a clade of herbivorous sea slugs. Evolutionary quantitative genetics modeling and stochastic character mapping supported 27 origins of lecithotrophy. Tests for correlated evolution revealed lecithotrophy evolved more often in lineages investing in extra-embryonic yolk, the first adult trait associated with shifts in development mode across a group. However, contrary to predictions from paleontological studies, species selection actually favored planktotrophy; most extant lecithotrophs originated through recent character change, and did not subsequently diversify. Increased offspring provisioning in planktotrophs thus favored shifts to short-lived larvae, which led to short-lived lineages over macroevolutionary time scales. These findings challenge long-standing assumptions about the effects of alternative life histories in the sea. Species selection can explain the long-term persistence of planktotrophy, the ancestral state in most clades, despite frequent transitions to lecithotrophy. PMID:26163664

  7. Freshly induced short-lived gamma-ray activity as a measure of fission rates in lightly re-irradiated spent fuel

    NASA Astrophysics Data System (ADS)

    Kröhnert, H.; Perret, G.; Murphy, M. F.; Chawla, R.

    2010-12-01

    A new measurement technique has been developed to determine fission rates in burnt fuel, following re-irradiation in a zero-power research reactor. The development has been made in the frame of the LIFE@PROTEUS program at the Paul Scherrer Institute, which aims at characterizing the interfaces between fresh and highly burnt fuel assemblies in modern LWRs. To discriminate against the high intrinsic gamma-ray activity of the burnt fuel, the proposed measurement technique uses high-energy gamma-rays, above 2000 keV, emitted by short-lived fission products freshly produced in the fuel. To demonstrate the feasibility of this technique, a fresh UO 2 sample and a 36 GWd/t burnt UO 2 sample were irradiated in the PROTEUS reactor and their gamma-ray activities were recorded directly after irradiation. For both fresh and the burnt fuel samples, relative fission rates were derived for different core positions, based on the short-lived 142La (2542 keV), 89Rb (2570 keV), 138Cs (2640 keV) and 95Y (3576 keV) gamma-ray lines. Uncertainties on the inter-position fission rate ratios were mainly due to the uncertainties on the net-area of the gamma-ray peaks and were about 1-3% for the fresh sample, and 3-6% for the burnt one. Thus, for the first time, it has been shown that the short-lived gamma-ray activity, induced in burnt fuel by irradiation in a zero-power reactor, can be used as a quantitative measure of the fission rate. For both fresh and burnt fuel, the measured results agreed, within the uncertainties, with Monte Carlo (MCNPX) predictions.

  8. 182Hf–182W age dating of a 26Al-poor inclusion and implications for the origin of short-lived radioisotopes in the early Solar System

    PubMed Central

    Holst, Jesper C.; Olsen, Mia B.; Paton, Chad; Nagashima, Kazuhide; Schiller, Martin; Wielandt, Daniel; Larsen, Kirsten K.; Connelly, James N.; Jørgensen, Jes K.; Krot, Alexander N.; Nordlund, Åke; Bizzarro, Martin

    2013-01-01

    Refractory inclusions [calcium–aluminum-rich inclusions, (CAIs)] represent the oldest Solar System solids and provide information regarding the formation of the Sun and its protoplanetary disk. CAIs contain evidence of now extinct short-lived radioisotopes (e.g., 26Al, 41Ca, and 182Hf) synthesized in one or multiple stars and added to the protosolar molecular cloud before or during its collapse. Understanding how and when short-lived radioisotopes were added to the Solar System is necessary to assess their validity as chronometers and constrain the birthplace of the Sun. Whereas most CAIs formed with the canonical abundance of 26Al corresponding to 26Al/27Al of ∼5 × 10−5, rare CAIs with fractionation and unidentified nuclear isotope effects (FUN CAIs) record nucleosynthetic isotopic heterogeneity and 26Al/27Al of <5 × 10−6, possibly reflecting their formation before canonical CAIs. Thus, FUN CAIs may provide a unique window into the earliest Solar System, including the origin of short-lived radioisotopes. However, their chronology is unknown. Using the 182Hf–182W chronometer, we show that a FUN CAI recording a condensation origin from a solar gas formed coevally with canonical CAIs, but with 26Al/27Al of ∼3 × 10−6. The decoupling between 182Hf and 26Al requires distinct stellar origins: steady-state galactic stellar nucleosynthesis for 182Hf and late-stage contamination of the protosolar molecular cloud by a massive star(s) for 26Al. Admixing of stellar-derived 26Al to the protoplanetary disk occurred during the epoch of CAI formation and, therefore, the 26Al–26Mg systematics of CAIs cannot be used to define their formation interval. In contrast, our results support 182Hf homogeneity and chronological significance of the 182Hf–182W clock. PMID:23671077

  9. 182Hf-182W age dating of a 26Al-poor inclusion and implications for the origin of short-lived radioisotopes in the early Solar System.

    PubMed

    Holst, Jesper C; Olsen, Mia B; Paton, Chad; Nagashima, Kazuhide; Schiller, Martin; Wielandt, Daniel; Larsen, Kirsten K; Connelly, James N; Jørgensen, Jes K; Krot, Alexander N; Nordlund, Ake; Bizzarro, Martin

    2013-05-28

    Refractory inclusions [calcium-aluminum-rich inclusions, (CAIs)] represent the oldest Solar System solids and provide information regarding the formation of the Sun and its protoplanetary disk. CAIs contain evidence of now extinct short-lived radioisotopes (e.g., (26)Al, (41)Ca, and (182)Hf) synthesized in one or multiple stars and added to the protosolar molecular cloud before or during its collapse. Understanding how and when short-lived radioisotopes were added to the Solar System is necessary to assess their validity as chronometers and constrain the birthplace of the Sun. Whereas most CAIs formed with the canonical abundance of (26)Al corresponding to (26)Al/(27)Al of ∼5 × 10(-5), rare CAIs with fractionation and unidentified nuclear isotope effects (FUN CAIs) record nucleosynthetic isotopic heterogeneity and (26)Al/(27)Al of <5 × 10(-6), possibly reflecting their formation before canonical CAIs. Thus, FUN CAIs may provide a unique window into the earliest Solar System, including the origin of short-lived radioisotopes. However, their chronology is unknown. Using the (182)Hf-(182)W chronometer, we show that a FUN CAI recording a condensation origin from a solar gas formed coevally with canonical CAIs, but with (26)Al/(27)Al of ∼3 × 10(-6). The decoupling between (182)Hf and (26)Al requires distinct stellar origins: steady-state galactic stellar nucleosynthesis for (182)Hf and late-stage contamination of the protosolar molecular cloud by a massive star(s) for (26)Al. Admixing of stellar-derived (26)Al to the protoplanetary disk occurred during the epoch of CAI formation and, therefore, the (26)Al-(26)Mg systematics of CAIs cannot be used to define their formation interval. In contrast, our results support (182)Hf homogeneity and chronological significance of the (182)Hf-(182)W clock. PMID:23671077

  10. Climate response to projected changes in short-lived species under an A1B scenario from 2000-2050 in the GISS climate model

    SciTech Connect

    Menon, Surabi; Shindell, Drew T.; Faluvegi, Greg; Bauer, Susanne E.; Koch, Dorothy M.; Unger, Nadine; Menon, Surabi; Miller, Ron L.; Schmidt, Gavin A.; Streets, David G.

    2007-03-26

    We investigate the climate forcing from and response to projected changes in short-lived species and methane under the A1B scenario from 2000-2050 in the GISS climate model. We present a meta-analysis of new simulations of the full evolution of gas and aerosol species and other existing experiments with variations of the same model. The comparison highlights the importance of several physical processes in determining radiative forcing, especially the effect of climate change on stratosphere-troposphere exchange, heterogeneous sulfate-nitrate-dust chemistry, and changes in methane oxidation and natural emissions. However, the impact of these fairly uncertain physical effects is substantially less than the difference between alternative emission scenarios for all short-lived species. The net global mean annual average direct radiative forcing from the short-lived species is .02 W/m{sup 2} or less in our projections, as substantial positive ozone forcing is largely offset by negative aerosol direct forcing. Since aerosol reductions also lead to a reduced indirect effect, the global mean surface temperature warms by {approx}0.07 C by 2030 and {approx}0.13 C by 2050, adding 19% and 17%, respectively, to the warming induced by long-lived greenhouse gases. Regional direct forcings are large, up to 3.8 W/m{sup 2}. The ensemble-mean climate response shows little regional correlation with the spatial pattern of the forcing, however, suggesting that oceanic and atmospheric mixing generally overwhelms the effect of even large localized forcings. Exceptions are the polar regions, where ozone and aerosols may induce substantial seasonal climate changes.

  11. Modifications in Dynamic Contrast-Enhanced Magnetic Resonance Imaging Parameters After α-Particle-Emitting {sup 227}Th-trastuzumab Therapy of HER2-Expressing Ovarian Cancer Xenografts

    SciTech Connect

    Heyerdahl, Helen; Røe, Kathrine; Brevik, Ellen Mengshoel; Dahle, Jostein

    2013-09-01

    Purpose: The purpose of this study was to investigate the effect of α-particle-emitting {sup 227}Th-trastuzumab radioimmunotherapy on tumor vasculature to increase the knowledge about the mechanisms of action of {sup 227}Th-trastuzumab. Methods and Materials: Human HER2-expressing SKOV-3 ovarian cancer xenografts were grown bilaterally in athymic nude mice. Mice with tumor volumes 253 ± 36 mm{sup 3} (mean ± SEM) were treated with a single injection of either {sup 227}Th-trastuzumab at a dose of 1000 kBq/kg body weight (treated group, n=14 tumors) or 0.9% NaCl (control group, n=10 tumors). Dynamic T1-weighted contrast-enhanced magnetic resonance imaging (DCEMRI) was used to study the effect of {sup 227}Th-trastuzumab on tumor vasculature. DCEMRI was performed before treatment and 1, 2, and 3 weeks after therapy. Tumor contrast-enhancement curves were extracted voxel by voxel and fitted to the Brix pharmacokinetic model. Pharmacokinetic parameters for the tumors that underwent radioimmunotherapy were compared with the corresponding parameters of control tumors. Results: Significant increases of k{sub ep}, the rate constant of diffusion from the extravascular extracellular space to the plasma (P<.05), and k{sub el,} the rate of clearance of contrast agent from the plasma (P<.01), were seen in the radioimmunotherapy group 2 and 3 weeks after injection, compared with the control group. The product of k{sub ep} and the amplitude parameter A, associated with increased vessel permeability and perfusion, was also significantly increased in the radioimmunotherapy group 2 and 3 weeks after injection (P<.01). Conclusions: Pharmacokinetic modeling of MRI contrast-enhancement curves evidenced significant alterations in parameters associated with increased tumor vessel permeability and tumor perfusion after {sup 227}Th-trastuzumab treatment of HER2-expressing ovarian cancer xenografts.

  12. Development of radioactive ion beam production systems for Tokai Radioactive Ion Acceleration Complex-High temperature ion source for short-lived isotopes.

    PubMed

    Otokawa, Y; Osa, A; Sato, T K; Matsuda, M; Ichikawa, S; Jeong, S C

    2010-02-01

    We have developed a new ion source system in the isotope separator on-line at Japan Atomic Energy Agency, for separation of short-lived isotopes produced by proton-induced fission of (238)U. The ion source system is a forced electron beam induced arc discharge version E type ion source with a target container. We successfully operated this system at 2000 degrees C as a result of reductions in volume of the ion source and the target container, introduction of heating method by electron bombardment, and improvement to the heat shield. This new ion source system was tested using (238)U of 640 mg/cm(2) with a proton primary beam of 30 MeV, 350 nA. Release times were measured for Kr, In, and Xe. The values of release times are 2.6 s for Kr, 1.8 s for In, and 4.6 s for Xe. In this work, the ion source system enabled us to mass-separate short-lived isotopes such as (93)Kr(T(1/2)=1.286 s), (129)In(T(1/2)=0.61 s), and (141)Xe(T(1/2)=1.73 s) with intensity of 10(3) ions/s. PMID:20192400

  13. Development of radioactive ion beam production systems for Tokai Radioactive Ion Acceleration Complex--High temperature ion source for short-lived isotopes

    SciTech Connect

    Otokawa, Y.; Osa, A.; Sato, T. K.; Matsuda, M.; Ichikawa, S.; Jeong, S. C.

    2010-02-15

    We have developed a new ion source system in the isotope separator on-line at Japan Atomic Energy Agency, for separation of short-lived isotopes produced by proton-induced fission of {sup 238}U. The ion source system is a forced electron beam induced arc discharge version E type ion source with a target container. We successfully operated this system at 2000 deg. C as a result of reductions in volume of the ion source and the target container, introduction of heating method by electron bombardment, and improvement to the heat shield. This new ion source system was tested using {sup 238}U of 640 mg/cm{sup 2} with a proton primary beam of 30 MeV, 350 nA. Release times were measured for Kr, In, and Xe. The values of release times are 2.6 s for Kr, 1.8 s for In, and 4.6 s for Xe. In this work, the ion source system enabled us to mass-separate short-lived isotopes such as {sup 93}Kr(T{sub 1/2}=1.286 s), {sup 129}In(T{sub 1/2}=0.61 s), and {sup 141}Xe(T{sub 1/2}=1.73 s) with intensity of 10{sup 3} ions/s.

  14. Development of radioactive ion beam production systems for Tokai Radioactive Ion Acceleration Complex—High temperature ion source for short-lived isotopesa)

    NASA Astrophysics Data System (ADS)

    Otokawa, Y.; Osa, A.; Sato, T. K.; Matsuda, M.; Ichikawa, S.; Jeong, S. C.

    2010-02-01

    We have developed a new ion source system in the isotope separator on-line at Japan Atomic Energy Agency, for separation of short-lived isotopes produced by proton-induced fission of U238. The ion source system is a forced electron beam induced arc discharge version E type ion source with a target container. We successfully operated this system at 2000 °C as a result of reductions in volume of the ion source and the target container, introduction of heating method by electron bombardment, and improvement to the heat shield. This new ion source system was tested using U238 of 640 mg/cm2 with a proton primary beam of 30 MeV, 350 nA. Release times were measured for Kr, In, and Xe. The values of release times are 2.6 s for Kr, 1.8 s for In, and 4.6 s for Xe. In this work, the ion source system enabled us to mass-separate short-lived isotopes such as K93r(T1/2=1.286 s), I129n(T1/2=0.61 s), and X141e(T1/2=1.73 s) with intensity of 103 ions/s.

  15. Short-lived species detection of nitrous acid by external-cavity quantum cascade laser based quartz-enhanced photoacoustic absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Yi, Hongming; Maamary, Rabih; Gao, Xiaoming; Sigrist, Markus W.; Fertein, Eric; Chen, Weidong

    2015-03-01

    Spectroscopic detection of short-lived gaseous nitrous acid (HONO) at 1254.85 cm-1 was realized by off-beam coupled quartz-enhanced photoacoustic spectroscopy (QEPAS) in conjunction with an external cavity quantum cascade lasers (EC-QCL). High sensitivity monitoring of HONO was performed within a very small gas-sample volume (of ˜40 mm3) allowing a significant reduction (of about 4 orders of magnitude) of air sampling residence time which is highly desired for accurate quantification of chemically reactive short-lived species. Calibration of the developed QEPAS-based HONO sensor was carried out by means of lab-generated HONO samples whose concentrations were determined by direct absorption spectroscopy involving a ˜109.5 m multipass cell and a distributed feedback QCL. A minimum detection limit (MDL) of 66 ppbv (1 σ) HONO was achieved at 70 mbar using a laser output power of 50 mW and 1 s integration time, which corresponded to a normalized noise equivalent absorption coefficient of 3.6 × 10-8 cm-1 W/Hz1/2. This MDL was down to 7 ppbv at the optimal integration time of 150 s. The corresponding 1σ minimum detected absorption coefficient is ˜1.1 × 10-7 cm-1 (MDL ˜ 3 ppbv) in 1 s and ˜1.1 × 10-8 cm-1 (MDL ˜ 330 pptv) in 150 s, respectively, with 1 W laser power.

  16. Development of a system for real-time measurements of metabolite transport in plants using short-lived positron-emitting radiotracers

    NASA Astrophysics Data System (ADS)

    Kiser, Matthew R.

    Over the past 200 years, the Earth's atmospheric carbon dioxide (CO 2) concentration has increased by more than 35%, and climate experts predict that CO2 levels may double by the end of this century. Understanding the mechanisms of resource management in plants is fundamental for predicting how plants will respond to the increase in atmospheric CO 2. Plant productivity sustains life on Earth and is a principal component of the planet's system that regulates atmospheric CO2 concentration. As such, one of the central goals of plant science is to understand the regulatory mechanisms of plant growth in a changing environment. Short-lived positron-emitting radiotracer techniques provide time-dependent data that are critical for developing models of metabolite transport and resource distribution in plants and their microenvironments. To better understand the effects of environmental changes on resource transport and allocation in plants, we have developed a system for real-time measurements of rnetabolite transport in plants using short-lived positron-emitting radio-tracers. This thesis project includes the design, construction, and demonstration of the capabilities of this system for performing real-time measurements of metabolite transport in plants. The short-lived radiotracer system described in this dissertation takes advantage of the combined capabilities and close proximity of two research facilities at. Duke University: the Triangle Universities Nuclear Laboratory (TUNL) and the Duke University Phytotron, which are separated by approximately 100 meters. The short-lived positron-emitting radioisotopes are generated using the 10-MV tandem Van de Graaff accelerator located in the main TUNL building, which provides the capability of producing short-lived positron-emitting isotopes such as carbon-11 (11C: 20 minute half-life), nitrogen-13 (13N; 10 minute half-life), fluorine-18 (18F; 110 minute half-life), and oxygen-15 (15O; 2 minute half-life). The radioisotopes may be introduced to plants as biologically active molecules such as 11CO2, N13O-3, 18F--[H2O], and H152O . Plants for these studies are grown in controlled-environment chambers at the Phytotron. The chambers offer an array of control for temperature, humidity, atmospheric CO2 concentration, and light intensity. Additionally, the Phytotron houses one large reach-in growth chamber that is dedicated to this project for radioisotope labeling measurements. There are several important properties of short-lived positron-emitting radio-tracers that make them well suited for use in investigating metabolite transport in plants. First, because the molecular mass of a radioisotope-tagged compound is only minutely different from the corresponding stable compound, radiotracer substances should be metabolized and transported in plants the same as their non-radioactive counterparts. Second, because the relatively high energy gamma rays emitted from electron-positron annihilation are attenuated very little by plant tissue, the real-time distribution of a radiotracer can be measured in vivo in plants. Finally, the short radioactive half-lives of these isotopes allow for repeat measurements on the same plant in a short period of time. For example, in studies of short-term environmental changes on plant metabolite dynamics, a single plant can be labeled multiple times to measure its responses to different, environmental conditions. Also, different short-lived radiotracers can be applied to the same plant over a short period of time to investigate the transport and allocation of various metabolites. This newly developed system provides the capabilities for production of 11CO2 at TUNL, transfer of the 11CO 2 gas from the target area at TUNL to a radiation-shielded cryogenic trap at the Phytotron, labeling of photoassimilates with 11C, and in vivo gamma-ray detection for real-time measurements of the radiotracer distribution in small plants. The experimental techniques and instrumentation that enabled the quantitative biological studies reported in this thesis were developed through a series of experiments made at TUNL and the Phytotron. Collimated single detectors and coincidence counting techniques were used to monitor the radiotracer distribution on a coarse spatial scale. Additionally, a prototype Versatile Imager for Positron Emitting Radiotracers (VIPER) was built to provide the capability of measuring radiotracer distributions in plants with high spatial resolution (˜2.5 mm). This device enables detailed quantification of real-time metabolite dynamics on fine spatial scales. The full capabilities of this radiotracer system were utilized in an investigation of the effects of elevated atmospheric CO2 concentration and root nutrient availability on the transport and allocation of recently fixed carbon, including that released from the roots via exudation or respiration, in two grass species. The 11CO2 gas was introduced to a leaf on the plants grown at either ambient or elevated atmospheric CO 2. Two sequential measurements were performed per day on each plant: a control nutrient solution labeling immediately followed by labeling with a 10-fold increase or decrease in nutrient concentration. The real-time distribution of 11C-labeled photoassimilate was measured in vivo throughout the plant and root environment. This measurement resulted in the first observation of a rapid plant response to short-term changes in nutrient availability via correlated changes in the photoassimilate allocation to root exudates. Our data indicated that root exudation was consistently enhanced at lower nutrient concentrations. Also, we found that elevated atmospheric CO2 increased the velocity of photoassimilate transport throughout the plant, enhanced root exudation in an annual crop grass, and reduced root exudation in a perennial native grass.

  17. Involvement of the molecular chaperone Ydj1 in the ubiquitin-dependent degradation of short-lived and abnormal proteins in Saccharomyces cerevisiae.

    PubMed Central

    Lee, D H; Sherman, M Y; Goldberg, A L

    1996-01-01

    In Escherichia coli and mitochondria, the molecular chaperone DnaJ is required not only for protein folding but also for selective degradation of certain abnormal polypeptides. Here we demonstrate that in the yeast cytosol, the homologous chaperone Ydj1 is also required for ubiquitin-dependent degradation of certain abnormal proteins. The temperature-sensitive ydj1-151 mutant showed a large defect in the overall breakdown of short-lived cell proteins and abnormal polypeptides containing amino acid analogs, especially at 38 degrees C. By contrast, the degradation of long-lived cell proteins, which is independent of ubiquitin, was not altered nor was cell growth affected. The inactivation of Ydj1 markedly reduced the rapid, ubiquitin-dependent breakdown of certain beta-galactosidase (beta-gal) fusion polypeptides. Although degradation of N-end rule substrates (arginine-beta-gal and leucine-beta-gal) and the B-type cyclin Clb5-beta-gal occurred normally, degradation of the abnormal polypeptide ubiquitin-proline-beta-gal (Ub-P-beta-gal) and that of the short-lived normal protein Gcn4 were inhibited. As a consequence of reduced degradation of Ub-P-beta-gal, the beta-gal activity was four to five times higher in temperature-sensitive ydj1-151 mutant cells than in wild-type cells; thus, the folding and assembly of this enzyme do not require Ydj1 function. In wild-type cells, but not in ydj1-151 mutant cells, this chaperone is associated with the short-lived substrate Ub-P-beta-gal and not with stable beta-gal constructs. Furthermore, in the ydj1-151 mutant, the ubiquitination of Ub-P-beta-gal was blocked and the total level of ubiquitinated protein in the cell was reduced. Thus, Ydj1 is essential for the ubiquitin-dependent degradation of certain proteins. This chaperone may facilitate the recognition of unfolded proteins or serve as a cofactor for certain ubiquitin-ligating enzymes. PMID:8756635

  18. Design a 10 kJ IS Mather Type Plasma Focus for Solid Target Activation to Produce Short-Lived Radioisotopes 12C(d,n)13N

    NASA Astrophysics Data System (ADS)

    Sadat Kiai, S. M.; Adlparvar, S.; Sheibani, S.; Elahi, M.; Safarien, A.; Farhangi, S.; Zirak, A. R.; Alhooie, S.; Mortazavi, B. N.; Khalaj, M. M.; Khanchi, A. R.; Dabirzadeh, A. A.; Kashani, A.; Zahedi, F.

    2010-10-01

    A 10 kJ (15 kV, 88 μF) IS (Iranian Sun) Mather type plasma focus device has been studied to determine the activity of a compound exogenous carbon solid target through 12C(d,n)13N nuclear reaction. The produced 13N is a short-lived radioisotope with a half-life of 9.97 min and threshold energy of 0.28 MeV. The results indicate that energetic deuterons impinging on the solid target can produce yield of = 6.7 × 10-5 with an activity of A = 6.8 × 104 Bq for one plasma focus shut and A ν = 4 × 105 Bq for 6 shut per mint when the projectile maximum deuterons energy is E max = 3 MeV.

  19. The Effect of Observers’ Mood on the Local Processing of Emotional Faces: Evidence from Short-Lived and Prolonged Mood States

    PubMed Central

    Mokhtari, Setareh; Buttle, Heather

    2015-01-01

    We examined the effect of induced mood, varying in valence and longevity, on local processing of emotional faces. It was found that negative facial expression conveyed by the global level of the face interferes with efficient processing of the local features. The results also showed that the duration of involvement with a mood influenced the local processing. We observed that attending to the local level of faces is not different in short-lived happy and sad mood states. However, as the mood state is experienced for a longer period, local processing was impaired in happy mood compared to sad mood. Taken together, we concluded that both facial expressions and affective states influence processing of the local parts of faces. Moreover, we suggest that mediating factors like the duration of involvement with the mood play a role in the interrelation between mood, attention, and perception. PMID:25883696

  20. Osteosarcoma risk after simultaneous incorporation of the long-lived radionuclide sup 227 Ac and the short-lived radionuclide sup 227 Th

    SciTech Connect

    Mueller, W.A.M.; Murray, A.B.; Linzner, U.; Luz, A. )

    1990-01-01

    The effect of injection of 1.85 kBq/kg of the long-lived radionuclide {sup 227}Ac on the induction of osteosarcomas in female NMRI mice by different dose levels (18.5, 74, and 185 kBq/kg) of the short-lived radionuclide {sup 227}Th was investigated. The highest absolute osteosarcoma incidence was observed with the highest doses of {sup 227}Th. Addition of {sup 227}Ac resulted in an additional osteosarcoma incidence only at the lowest dose of {sup 227}Th and did not affect the osteosarcoma incidence resulting from higher doses of {sup 227}Th. The longest times to tumor appearance were observed with {sup 227}Ac alone. The latent period in two different age groups (4 weeks and 10-12 weeks) appeared to be similar following injection with combined doses of {sup 227}Th and {sup 227}Ac but different after injection of each radionuclide alone.

  1. Short-lived species detection of nitrous acid by external-cavity quantum cascade laser based quartz-enhanced photoacoustic absorption spectroscopy

    SciTech Connect

    Yi, Hongming; Maamary, Rabih; Fertein, Eric; Chen, Weidong; Gao, Xiaoming; Sigrist, Markus W.

    2015-03-09

    Spectroscopic detection of short-lived gaseous nitrous acid (HONO) at 1254.85 cm{sup −1} was realized by off-beam coupled quartz-enhanced photoacoustic spectroscopy (QEPAS) in conjunction with an external cavity quantum cascade lasers (EC-QCL). High sensitivity monitoring of HONO was performed within a very small gas-sample volume (of ∼40 mm{sup 3}) allowing a significant reduction (of about 4 orders of magnitude) of air sampling residence time which is highly desired for accurate quantification of chemically reactive short-lived species. Calibration of the developed QEPAS-based HONO sensor was carried out by means of lab-generated HONO samples whose concentrations were determined by direct absorption spectroscopy involving a ∼109.5 m multipass cell and a distributed feedback QCL. A minimum detection limit (MDL) of 66 ppbv (1 σ) HONO was achieved at 70 mbar using a laser output power of 50 mW and 1 s integration time, which corresponded to a normalized noise equivalent absorption coefficient of 3.6 × 10{sup −8 }cm{sup −1} W/Hz{sup 1/2}. This MDL was down to 7 ppbv at the optimal integration time of 150 s. The corresponding 1σ minimum detected absorption coefficient is ∼1.1 × 10{sup −7 }cm{sup −1} (MDL ∼ 3 ppbv) in 1 s and ∼1.1 × 10{sup −8 }cm{sup −1} (MDL ∼ 330 pptv) in 150 s, respectively, with 1 W laser power.

  2. Triggering collapse of the presolar dense cloud core and injecting short-lived radioisotopes with a shock wave. III. Rotating three-dimensional cloud cores

    SciTech Connect

    Boss, Alan P.; Keiser, Sandra A.

    2014-06-10

    A key test of the supernova triggering and injection hypothesis for the origin of the solar system's short-lived radioisotopes is to reproduce the inferred initial abundances of these isotopes. We present here the most detailed models to date of the shock wave triggering and injection process, where shock waves with varied properties strike fully three-dimensional, rotating, dense cloud cores. The models are calculated with the FLASH adaptive mesh hydrodynamics code. Three different outcomes can result: triggered collapse leading to fragmentation into a multiple protostar system; triggered collapse leading to a single protostar embedded in a protostellar disk; or failure to undergo dynamic collapse. Shock wave material is injected into the collapsing clouds through Rayleigh-Taylor fingers, resulting in initially inhomogeneous distributions in the protostars and protostellar disks. Cloud rotation about an axis aligned with the shock propagation direction does not increase the injection efficiency appreciably, as the shock parameters were chosen to be optimal for injection even in the absence of rotation. For a shock wave from a core-collapse supernova, the dilution factors for supernova material are in the range of ∼10{sup –4} to ∼3 × 10{sup –4}, in agreement with recent laboratory estimates of the required amount of dilution for {sup 60}Fe and {sup 26}Al. We conclude that a type II supernova remains as a promising candidate for synthesizing the solar system's short-lived radioisotopes shortly before their injection into the presolar cloud core by the supernova's remnant shock wave.

  3. Short Lived Climate Pollutants cause a Long Lived Effect on Sea-level Rise: Analyzing climate metrics for sea-level rise

    NASA Astrophysics Data System (ADS)

    Sterner, E.; Johansson, D. J.

    2013-12-01

    Climate change depends on the increase of several different atmospheric pollutants. While long term global warming will be determined mainly by carbon dioxide, warming in the next few decades will depend to a large extent on short lived climate pollutants (SLCP). Reducing emissions of SLCPs could contribute to lower the global mean surface temperature by 0.5 °C already by 2050 (Shindell et al. 2012). Furthermore, the warming effect of one of the most potent SLCPs, black carbon (BC), may have been underestimated in the past. Bond et al. (2013) presents a new best estimate of the total BC radiative forcing (RF) of 1.1 W/m2 (90 % uncertainty bounds of 0.17 to 2.1 W/m2) since the beginning of the industrial era. BC is however never emitted alone and cooling aerosols from the same sources offset a majority of this RF. In the wake of calls for mitigation of SLCPs it is important to study other aspects of the climate effect of SLCPs. One key impact of climate change is sea-level rise (SLR). In a recent study, the effect of SLCP mitigation scenarios on SLR is examined. Hu et al (2013) find a substantial effect on SLR from mitigating SLCPs sharply, reducing SLR by 22-42% by 2100. We choose a different approach focusing on emission pulses and analyse a metric based on sea level rise so as to further enlighten the SLR consequences of SLCPs. We want in particular to understand the time dynamics of SLR impacts caused by SLCPs compared to other greenhouse gases. The most commonly used physical based metrics are GWP and GTP. We propose and evaluate an additional metric: The global sea-level rise potential (GSP). The GSP is defined as the sea level rise after a time horizon caused by an emissions pulse of a forcer to the sea level rise after a time horizon caused by an emissions pulse of a CO2. GSP is evaluated and compared to GWP and GTP using a set of climate forcers chosen to cover the whole scale of atmospheric perturbation life times (BC, CH4, N2O, CO2 and SF6). The study utilizes an upwelling diffusion energy balance model and focuses on the thermosteric part of sea-level rise. Example GSP results are 244, 15 and 278 for BC, CH4 and N2O for a time horizon of 100 years. Compare GWP and GTP values of 405, 24 and 288 as well as 62, 4.5 and 252. The main result of the study is that no climate forcer is in any absolute sense short lived when it comes to Sea Level impacts. All of the examined climate forcers have considerable influence on the thermosteric SLR, and the closely linked ocean heat content, on the time scale of centuries. The reason for this is that heat, once it has been induced by the climate drivers and warmed the surface ocean, is transported down into the slowly mixing oceans. References: Shindell, D. et al. Simultaneously mitigating near-term climate change and improving human health and food security. Science 335, 183-189 (2012). Bond, T. C. et al. Bounding the role of black carbon in the climate system: A scientific assessment. Journal of Geophysical Research: Atmospheres 118 5380-5552 (2013). Hu, A., Xu, Y., Tebaldi, C., Washington, W. M. & Ramanathan, V. Mitigation of short-lived climate pollutants slows sea-level rise. Nature Climate Change 3, 730-734 (2013).

  4. Composition and Trends of Short-Lived Trace Gases in the UT/LS over Europe Observed by the CARIBIC Aircraft

    NASA Astrophysics Data System (ADS)

    Baker, A. K.; Brenninkmeijer, C. A.; Oram, D. E.; O'Sullivan, D. A.; Slemr, F.; Schuck, T. J.

    2009-12-01

    The CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) involves the monthly deployment of an instrument container equipped to make atmospheric measurements from aboard a commercial airliner, and has operated since 2005 from aboard a Lufthansa Airbus 340-600 . Measurements from the container include in-situ trace gas and aerosol analyses and the collection of aerosol and whole air samples for post-flight laboratory analysis. Measurements made from the sampling flasks include greenhouse gas (GHG), halocarbon and nonmethane hydrocarbon (NMHC) analysis. CARIBIC flights originate in Frankfurt, Germany with routes to India, East Asia, South America, North America and Africa, and typical aircraft cruising altitudes of 10-12km allow for the monitoring of the upper troposphere/lower stratosphere (UT/LS) along these routes. Data collected during the aircraft’s departure from and return to Frankfurt provide a 4 year time series of near-monthly measurements of the composition of the UT/LS above Europe. Here we present a discussion of the composition of short-lived trace gases in the whole air samples collected above Europe during CARIBIC flights. Over 150 air samples were collected between May 2005 and July 2009, or about 4 samples per month. Of the whole air samples collected, about 45% showed influence by stratospheric air (i.e. very low values of GHG, NMHC and halocarbons, elevated O3, high potential vorticity). The remaining samples were representative of the upper troposphere; back trajectories for these samples indicate that a little over half were collected in air masses that had been in the boundary layer within the previous 8 days. The predominant source regions for these samples were the Gulf of Mexico and continental North America. Owing to their wide range of chemical lifetimes and the varying composition of emissions, short-lived trace gases transported to the UT/LS can be useful indicators of source region, photochemical processing and transport timescales of an air mass. Seasonal and longer-term trends in trace gases and trace gas composition are discussed, as well as composition of air masses having different origins. Additionally, we apply relationships between the different species, particularly the NMHC, to gain a qualitative understanding of photochemical processes occurring during transport from the boundary layer to the upper troposphere over Europe.

  5. An alternative approach to comparing long- and short-lived emissions in light of the 2&amp;deg;C global temperature limit

    NASA Astrophysics Data System (ADS)

    Smith, Stephen; Bowerman, Niel; Lowe, Jason; Huntingford, Chris; Frame, Dave; Allen, Myles; Gohar, Laila; Millar, Richard

    2014-05-01

    International climate policy has defined its goal in terms of limiting global average temperature, specifically to 2°C above pre-industrial levels. Emissions of several different greenhouse gases (GHGs) are currently aggregated and traded in terms of their carbon dioxide equivalent. The metric used for aggregating and trading is the 100-year Global Warming Potential (GWP100). Importantly though, the GWP100 does not measure temperature and so does clearly indicate the relative value of different emissions in the context of a global temperature limit. Recent developments in climate research have led to two different, potentially conflicting, perspectives on priorities in reducing emissions. First, a clear link has been demonstrated between cumulative emissions of carbon dioxide and peak temperature. This emphasises the need for carbon dioxide emissions to fall to near zero and provides a conceptually neat way to frame policy, but says little about the role of other GHGs. Second, other studies have shown that emissions of short-lived climate pollutants (SLCPs), many of which currently lie outside climate policy, have a substantial near-term effect on climate. It has been suggested that immediate SLCP reductions will therefore increase the chance of staying below 2°C and may even "buy time" for carbon dioxide reductions. This presentation summarises two recent papers which clarify the roles of SLCPs and long-lived GHGs in determining peak global temperature, and propose new emission metrics to reflect these. SLCP emissions reductions in a given decade have a significant impact on peak temperature only if carbon dioxide emissions are already falling. Immediate action on SLCPs might potentially "buy time" for adaptation by reducing near-term warming, but it does not buy time to delay reductions in carbon dioxide compared with delayed SLCP reductions. Peak temperature is ultimately constrained by cumulative emissions of several long-lived gases (including carbon dioxide) and sustained emission rates of a separate basket of shorter-lived species (including methane and other SLCPs). For these two baskets we develop an emissions-equivalence metric which allows trading within, but not between, each basket. The 2°C limit could therefore be met by setting a limit to cumulative long-lived emissions while setting a maximum future rate for short-lived emissions.

  6. Very short-lived bromomethanes measured by the CARIBIC observatory over the North Atlantic, Africa and South-East Asia during 2009-2013

    NASA Astrophysics Data System (ADS)

    Wisher, A.; Oram, D. E.; Laube, J. C.; Mills, G. P.; van Velthoven, P.; Zahn, A.; Brenninkmeijer, C. A. M.

    2013-11-01

    Short-lived organic brominated compounds make up a significant part (~20%) of the organic bromine budget in the atmosphere. Emissions of these compounds are highly variable and there are limited measurements, particularly in the extra-tropical upper troposphere/lower stratosphere and tropical troposphere. Measurements of five short-lived bromomethanes (VSLB) were made in air samples collected on the CARIBIC project aircraft over three flight routes; Germany to Venezuela/Columbia during 2009-2011, Germany to South Africa during 2010 and 2011 and Germany to Thailand/Kuala Lumpur, Malaysia during 2012 and 2013. In the tropical troposphere, as the most important entrance region to the stratosphere, we observe a total mean organic bromine derived from these compounds across all flights at 10-12 km altitude of 3.4 ± 1.5 ppt. Individual mean tropical tropospheric mixing ratios across all flights were 0.43, 0.74, 0.14, 0.23 and 0.11 ppt for CHBr3, CH2Br2, CHBr2Cl, CHBrCl2 and CH2BrCl respectively. The highest levels of VSLS-derived bromine (4.20 ± 0.56 ppt) were observed in flights between Bangkok and Kuala Lumpur indicating that the South China Sea is an important source region for these compounds. Across all routes, CHBr3 and CH2Br2 accounted for 34% (4.7-71) and 48% (14-73) respectively of total bromine derived from the analysed VSLB in the tropical mid-upper troposphere totalling 82% (54-89). In samples collected between Germany and Venezuela/Columbia, we find decreasing mean mixing ratios with increasing potential temperature in the extra-tropics. Tropical mean mixing ratios are higher than extra-tropical values between 340-350 K indicating that rapid uplift is important in determining mixing ratios in the lower tropical tropopause layer in the West Atlantic tropics. O3 was used as a tracer for stratospherically influenced air and we detect rapidly decreasing mixing ratios for all VSLB above ~100 ppb O3 corresponding to the extra-tropical tropopause layer.

  7. Very short-lived bromomethanes measured by the CARIBIC observatory over the North Atlantic, Africa and Southeast Asia during 2009-2013

    NASA Astrophysics Data System (ADS)

    Wisher, A.; Oram, D. E.; Laube, J. C.; Mills, G. P.; van Velthoven, P.; Zahn, A.; Brenninkmeijer, C. A. M.

    2014-04-01

    Short-lived organic brominated compounds make up a significant part of the organic bromine budget in the atmosphere. Emissions of these compounds are highly variable and there are limited measurements, particularly in the extra-tropical upper troposphere/lower stratosphere and tropical troposphere. Measurements of five very short-lived bromomethanes (VSLB) were made in air samples collected on the CARIBIC project aircraft over three flight routes; Germany to Venezuela/Columbia during 2009-2011, Germany to South Africa during 2010 and 2011 and Germany to Thailand/Kuala Lumpur, Malaysia during 2012 and 2013. In the tropical troposphere, as the most important entrance region to the stratosphere, we observe a total mean organic bromine derived from these compounds across all flights at 10-12 km altitude of 3.4 ± 1.5 ppt. Individual mean tropical tropospheric mixing ratios across all flights were 0.43, 0.74, 0.14, 0.23 and 0.11 ppt for CHBr3, CH2Br2, CHBr2Cl, CHBrCl2 and CH2BrCl respectively. The highest levels of VSLB-derived bromine (4.20 ± 0.56 ppt) were observed in flights between Bangkok and Kuala Lumpur indicating that the South China Sea is an important source region for these compounds. Across all routes, CHBr3 and CH2Br2 accounted for 34% (4.7-71) and 48% (14-73) respectively of total bromine derived from the analysed VSLB in the tropical mid-upper troposphere totalling 82% (54-89). In samples collected between Germany and Venezuela/Columbia, we find decreasing mean mixing ratios with increasing potential temperature in the extra-tropics. Tropical mean mixing ratios are higher than extra-tropical values between 340-350 K indicating that rapid uplift is important in determining mixing ratios in the lower tropical tropopause layer in the West Atlantic tropics. O3 was used as a tracer for stratospherically influenced air and we detect rapidly decreasing mixing ratios for all VSLB above ∼100 ppb O3 corresponding to the extra-tropical tropopause layer.

  8. The possibility to measure the magnetic moments of short-lived particles (charm and beauty baryons) at LHC and FCC energies using the phenomenon of spin rotation in crystals

    NASA Astrophysics Data System (ADS)

    Baryshevsky, V. G.

    2016-06-01

    The use of spin rotation effect in bent crystals for measuring the magnetic moment of short-lived particles in the range of LHC and FCC energies is considered. It is shown that the estimated number of produced baryons that are captured into a bent crystal grows as ∼γ 3 / 2 with increasing particle energy. Hence it may be concluded that the experimental measurement of magnetic moments of short-lived particles using the spin rotation effect is feasible at LHC and higher energies (for LHC energies, e.g., the running time required for measuring the magnetic moment of Λc+is 2 ÷ 16 hours).

  9. Lyman alpha radiation in external galaxies

    NASA Technical Reports Server (NTRS)

    Neufeld, David A.; Mckee, Christopher F.

    1990-01-01

    The Ly alpha line of atomic hydrogen is often a luminous component of the radiation emitted by distant galaxies. Except for those galaxies which have a substantial central source of non-stellar ionizing radiation, most of the Ly alpha radiation emitted by galaxies is generated within regions of the interstellar medium which are photoionized by starlight. Conversely, much of the energy radiated by photoionized regions is carried by the Ly alpha line. Only hot, massive stars are capable of ionizing hydrogen in the interstellar medium which surrounds them, and because such stars are necessarily short-lived, Ly alpha emission traces regions of active star formation. Researchers argue that the strength of the Ly alpha emission observed from external galaxies may be used to estimate quantitatively the dust content of the emitting region, while the Ly alpha line profile is sensitive to the presence of shock waves. Interstellar dust particles and shock waves are intimately associated with the process of star formation in two senses. First, both dust particles and shock waves owe their existence to stellar activity; second, they may both serve as agents which facilitate the formation of stars, shocks by triggering gravitational instabilities in the interstellar gas that they compress, and dust by shielding star-forming molecular clouds from the ionizing and dissociative effects of external UV radiation. By using Ly alpha observations as a probe of the dust content in diffuse gas at high redshift, we might hope to learn about the earliest epochs of star formation.

  10. Alpha Thalassemia

    MedlinePlus

    Alpha Thalassemia Physicians often mistake alpha thalassemia trait for iron deficiency anemia and incorrectly prescribe iron supplements that have no effect 1 on the anemia. αα αα Normal alpha globin genes ...

  11. Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

    NASA Astrophysics Data System (ADS)

    Monks, P. S.; Archibald, A. T.; Colette, A.; Cooper, O.; Coyle, M.; Derwent, R.; Fowler, D.; Granier, C.; Law, K. S.; Stevenson, D. S.; Tarasova, O.; Thouret, V.; von Schneidemesser, E.; Sommariva, R.; Wild, O.; Williams, M. L.

    2014-12-01

    Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a by-product of the very oxidation chemistry it largely initiates. Much effort is focussed on the reduction of surface levels of ozone owing to its health impacts but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve due to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate-change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner.

  12. Combining radon, short-lived radium isotopes and hydrodynamic modeling to assess submarine groundwater discharge from an anthropized semiarid watershed to a Mediterranean lagoon (Mar Menor, SE Spain)

    NASA Astrophysics Data System (ADS)

    Baudron, Paul; Cockenpot, Sabine; Lopez-Castejon, Francisco; Radakovitch, Olivier; Gilabert, Javier; Mayer, Adriano; Garcia-Arostegui, José Luis; Martinez-Vicente, David; Leduc, Christian; Claude, Christelle

    2015-06-01

    In highly anthropized watersheds, surface water tributaries may carry unexpected high quantities of radon and radium to coastal lagoons. Investigating submarine groundwater discharge (SGD) with radionuclide tracers is therefore a complex task. In order to quantify SGD and decipher the influence of the different water sources, we combined a radon (222Rn) and short-lived radium (223Ra, 224Ra) survey with the hydrodynamic modeling of a lagoon. We applied it to the Mar Menor lagoon (SE Spain) where surface water tributaries and undocumented emissaries carry water from groundwater drainage and brines from groundwater desalinization. We identified the areas of influence of the plume of radionuclides from the river, located major areas of SGD and proposed a location for two submarine emissaries. Porewater, i.e. interstitial water from underlying sediments, was found to be the most representative SGD end member, compared to continental groundwater collected from piezometers. Mass balances in winter and summer seasons provided yearly SGD fluxes of water of 0.4-2.2 ṡ 108 m3/y (222Rn), 4.4-19.0 ṡ 108 m3/y (224Ra) and 1.3 ṡ 108 m3/y (223Ra, measured in winter only). Tidal pumping was identified as a main driver for recirculated saline groundwater, while fresh submarine groundwater discharge from the aquifer ranged between 2% and 23% of total SGD.

  13. Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

    NASA Astrophysics Data System (ADS)

    Monks, P. S.; Archibald, A. T.; Colette, A.; Cooper, O.; Coyle, M.; Derwent, R.; Fowler, D.; Granier, C.; Law, K. S.; Mills, G. E.; Stevenson, D. S.; Tarasova, O.; Thouret, V.; von Schneidemesser, E.; Sommariva, R.; Wild, O.; Williams, M. L.

    2015-08-01

    Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a byproduct of the very oxidation chemistry it largely initiates. Much effort is focused on the reduction of surface levels of ozone owing to its health and vegetation impacts, but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve owing to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner. The review shows that there remain a number of clear challenges for ozone such as explaining surface trends, incorporating new chemical understanding, ozone-climate coupling, and a better assessment of impacts. There is a clear and present need to treat ozone across the range of scales, a transboundary issue, but with an emphasis on the hemispheric scales. New observational opportunities are offered both by satellites and small sensors that bridge the scales.

  14. Two promising future developments of cryo-EM: capturing short-lived states and mapping a continuum of states of a macromolecule.

    PubMed

    Chen, Bo; Frank, Joachim

    2016-02-01

    The capabilities and application range of cryogenic electron microscopy (cryo-EM) method have expanded vastly in the last two years, thanks to the advances provided by direct detection devices and computational classification tools. We take this review as an opportunity to sketch out promising developments of cryo-EM in two important directions: (i) imaging of short-lived states (10-1000 ms) of biological molecules by using time-resolved cryo-EM, particularly the mixing-spraying method and (ii) recovering an entire continuum of coexisting states from the same sample by employing a computational technique called manifold embedding. It is tempting to think of combining these two methods, to elucidate the way the states of a molecular machine such as the ribosome branch and unfold. This idea awaits further developments of both methods, particularly by increasing the data yield of the time-resolved cryo-EM method and by developing the manifold embedding technique into a user-friendly workbench. PMID:26520784

  15. Kinetics and Mechanism of the Chlorite-Periodate System: Formation of a Short-Lived Key Intermediate OClOIO3 and Its Subsequent Reactions.

    PubMed

    Baranyi, Nóra; Csekő, György; Valkai, László; Xu, Li; Horváth, Attila K

    2016-03-01

    The chlorite-periodate reaction has been studied spectrophotometrically in acidic medium at 25.0 ± 0.1 °C, monitoring the absorbance at 400 nm in acetate/acetic acid buffer at constant ionic strength (I = 0.5 M). We have shown that periodate was exclusively reduced to iodate, but chlorite ion was oxidized to chlorate and chlorine dioxide via branching pathways. The stoichiometry of the reaction can be described as a linear combination of two limiting stoichiometries under our experimental conditions. Detailed initial rate studies have clearly revealed that the formal kinetic orders of hydrogen ion, chlorite ion, and periodate ion are all strictly one, establishing an empirical rate law to be d[ClO2]/dt = kobs[ClO2(-)][IO4(-)][H(+)], where the apparent rate coefficient (kobs) was found to be 70 ± 13 M(-2) s(-1). On the basis of the experiments, a simple four-step kinetic model with three fitted kinetic parameters is proposed by nonlinear parameter estimation. The reaction was found to proceed via a parallel oxygen transfer reaction leading to the exclusive formation of chlorate and iodate as well as via the formation of a short-lived key intermediate OClOIO3 followed by its further transformations by a sequence of branching pathways. PMID:26849795

  16. Effective Strategy for Conformer-Selective Detection of Short-Lived Excited State Species: Application to the IR Spectroscopy of the N1H Keto Tautomer of Guanine.

    PubMed

    Asami, Hiroya; Tokugawa, Munefumi; Masaki, Yoshiaki; Ishiuchi, Shun-Ichi; Gloaguen, Eric; Seio, Kohji; Saigusa, Hiroyuki; Fujii, Masaaki; Sekine, Mitsuo; Mons, Michel

    2016-04-14

    The ultrafast deactivation processes in the excited state of biomolecules, such as the most stable tautomers of guanine, forbid any state-of-the-art gas phase spectroscopic studies on these species with nanosecond lasers. This drawback can be overcome by grafting a chromophore having a long-lived excited state to the molecule of interest, allowing thus a mass-selective detection by nanosecond R2PI and therefore double resonance IR/UV conformer-selective spectroscopic studies. The principle is presently demonstrated on the keto form of a modified 9-methylguanine, for which the IR/UV double resonance spectrum in the C═O stretch region, reported for the first time, provides evidence for extensive vibrational couplings within the guanine moiety. Such a successful strategy opens up a route to mass-selective IR/UV spectroscopic investigations on molecules exhibiting natural chromophores having ultrashort-lived excited states, such as DNA bases, their complexes as well as peptides containing short-lived aromatic residues. PMID:26990184

  17. Climate impacts of short-lived climate forcers versus CO2 from biodiesel: a case of the EU on-road sector.

    PubMed

    Lund, Marianne T; Berntsen, Terje K; Fuglestvedt, Jan S

    2014-12-16

    Biofuels are proposed to play an important role in several mitigation strategies to meet future CO2 emission targets for the transport sector but remain controversial due to significant uncertainties in net impacts on environment, society, and climate. A switch to biofuels can also affect short-lived climate forcers (SLCFs), which provide significant contributions to the net climate impact of transportation. We quantify the radiative forcing (RF) and global-mean temperature response over time to EU on-road fossil diesel SLCFs and the impact of 20% (B20) and 100% (B100) replacement of fossil diesel by biodiesel. SLCFs are compared to impacts of on-road CO2 using different approaches from existing literature to account for biodiesel CO2. Given the best estimates for changes in emissions when replacing fossil diesel with biodiesel, the net positive RF from EU on-road fossil diesel SLCFs of 3.4 mW/m(2) is reduced by 15% and 80% in B20 and B100, respectively. Over time the warming of SLCFs is likely small compared to biodiesel CO2 impacts. However, SLCFs may be relatively more important for the total warming than in the fossil fuel case if biodiesel from feedstock with very short rotation periods and low land-use-change impacts replaces a high fraction of fossil diesel. PMID:25405926

  18. Effects of Soy-derived diets on plasma and liver lipids, glucose tolerance, and longevity in normal, long-lived and short-lived mice.

    PubMed

    Bartke, A; Peluso, M R; Moretz, N; Wright, C; Bonkowski, M; Winters, T A; Shanahan, M F; Kopchick, J J; Banz, W J

    2004-08-01

    We examined the effects of diets based on a low isoflavone or a high isoflavone soy protein isolates in normal, growth-hormone receptor knockout and Ames dwarf, and Prop 1 (df) mice that are hypoinsulinemic, insulin-sensitive, and exceptionally long-lived, as well as in growth hormone transgenic mice that are hyperinsulinemic, insulin-resistant, dyslipidemic, and short-lived. Soybean diets tended to normalize plasma cholesterol levels in dwarf and transgenic mice, while low isoflavone diet reduced plasma triglycerides in most of the examined genotypes. The effects of low isoflavone and high isoflavone diets on the levels of free and esterified cholesterol in the liver were strongly genotype-dependent. Fasting blood glucose levels were reduced and glucose tolerance improved by both low isoflavone and high isoflavone diets in growth hormone-transgenic mice and in their normal siblings. Glucose tolerance was also improved by high-isoflavone diet in growth hormone receptor knockout mice. Lifespan was increased by low isoflavone diet in normal mice from two of the examined stocks. High isoflavone diet increased lifespan in normal animals from one line, but reduced lifespan of normal mice from a different line. We conclude that dietary soy protein intake can improve plasma and hepatic lipid profiles, reduce fasting glucose, enhance capacity for glucose tolerance, and prolong life, but all of these effects are strongly genotype-dependent. PMID:15326565

  19. Properties of the short-lived triplet states of pyridazine and 3,6-dichloropyridazine studied by a time-resolved EPR method

    NASA Astrophysics Data System (ADS)

    Terazima, Masahide; Yamauchi, Seigo; Hirota, Noboru

    1986-04-01

    The magnetic and decay properties of the short-lived triplet (T1) states of pyridazine and 3,6-dichloropyridazine (DCP) were studied by means of time-resolved EPR with laser excitation. The zfs of DCP in the p-dibromobenzene (DBB) host are X=0.094 cm-1, Y=-0.164 cm-1, and Z=0.070 cm-1, and the nitrogen hfcc are Ax=27 G, Ay=18 G, and Az=25 G, which confirms the nπ* character of the T1 state. Similar zfs were obtained for DCP and pyridazine in other environments. The sublevel decay rate constants and the relative populating rates were determined from the analysis of the transient EPR signals measured at 3.0 K where the effect of the spin lattice relaxation can be neglected. It was found in both systems that ky is much greater than kx, kz as predicted by a simple group theoretical consideration. ky of DCP and pyridazine were determined to be on the order of 106 s-1, being larger than that of pyrimidine by a factor of ˜104. The reasons for the large ky are discussed, particularly, in terms of the distorted potential of the T1 state.

  20. Studying the decay phase of a short-lived active region with coordinated DST/IBIS, Hinode/EIS+SOT+XRT, SOHO/MDI and TRACE observations

    NASA Astrophysics Data System (ADS)

    Zuccarello, F.; Berrilli, F.; Centrone, M.; Contarino, L.; Criscuoli, S.; Del Moro, D.; Ermolli, I.; Giorgi, F.; Guglielmino, L. S.; Salerno, C.; Spadaro, D.; Romano, P.

    2008-09-01

    This study concerns the physical processes occurring during the decay phase of the short-lived active region NOAA 10977, as evaluated from analysis of data gathered using ground- (DST/IBIS) and space-based (Hinode/EIS+SOT+XRT, SOHO/MDI and TRACE) facilities. The coordinated observing campaign was performed from December 1st to 9th, 2007, covering several spectral ranges, with unprecedented spatial and spectral resolution. We present preliminary results of the Doppler analysis of plasma motions evaluated from monochromatic images taken along the Ca II (8542 Å) and the Fe I (7049 Å) spectral lines with IBIS. We also report results concerning the horizontal displacements of photospheric magnetic structures and advection flows as obtained from application of Local Correlation Tracking (LCT) and Two-Level Structure Tracking (TST) techniques to both the LoS magnetograms taken by MDI and to high resolution intensity maps obtained by IBIS at DST/NSO. Further contributions to understanding the mechanisms at the base of the magnetic field diffusion are provided from the inversion of the Stokes profiles of the photospheric Fe I lines at 6301.5 Å and 6302.5 Å, obtained with SOT/SP, and the analysis of filtergrams in the core of the Ca II H line (3968.5 ± 3 Å) and images in G-band (4305 ± 8 Å) taken by SOT/BFI, as well as EIS data and images taken by the thin Be of XRT, and by TRACE at 171 Å and 1600 Å.

  1. RNA-seq of the aging brain in the short-lived fish N. furzeri – conserved pathways and novel genes associated with neurogenesis

    PubMed Central

    Baumgart, Mario; Groth, Marco; Priebe, Steffen; Savino, Aurora; Testa, Giovanna; Dix, Andreas; Ripa, Roberto; Spallotta, Francesco; Gaetano, Carlo; Ori, Michela; Terzibasi Tozzini, Eva; Guthke, Reinhard; Platzer, Matthias; Cellerino, Alessandro

    2014-01-01

    The brains of teleost fish show extensive adult neurogenesis and neuronal regeneration. The patterns of gene regulation during fish brain aging are unknown. The short-lived teleost fish Nothobranchius furzeri shows markers of brain aging including reduced learning performances, gliosis, and reduced adult neurogenesis. We used RNA-seq to quantify genome-wide transcript regulation and sampled five different time points to characterize whole-genome transcript regulation during brain aging of N. furzeri. Comparison with human datasets revealed conserved up-regulation of ribosome, lysosome, and complement activation and conserved down-regulation of synapse, mitochondrion, proteasome, and spliceosome. Down-regulated genes differ in their temporal profiles: neurogenesis and extracellular matrix genes showed rapid decay, synaptic and axonal genes a progressive decay. A substantial proportion of differentially expressed genes (∼40%) showed inversion of their temporal profiles in the last time point: spliceosome and proteasome showed initial down-regulation and stress-response genes initial up-regulation. Extensive regulation was detected for chromatin remodelers of the DNMT and CBX families as well as members of the polycomb complex and was mirrored by an up-regulation of the H3K27me3 epigenetic mark. Network analysis showed extensive coregulation of cell cycle/DNA synthesis genes with the uncharacterized zinc-finger protein ZNF367 as central hub. In situ hybridization showed that ZNF367 is expressed in neuronal stem cell niches of both embryonic zebrafish and adult N. furzeri. Other genes down-regulated with age, not previously associated with adult neurogenesis and with similar patterns of expression are AGR2, DNMT3A, KRCP, MEX3A, SCML4, and CBX1. CBX7, on the other hand, was up-regulated with age. PMID:25059688

  2. The Multi-Temporal Database of Planetary Image Data (MUTED): A database to support the identification of surface changes and short-lived surface processes

    NASA Astrophysics Data System (ADS)

    Erkeling, G.; Luesebrink, D.; Hiesinger, H.; Reiss, D.; Heyer, T.; Jaumann, R.

    2016-06-01

    Images of Mars taken by spacecraft in the last few decades indicate that the landscape has changed and that current processes are continuously changing the surface. The modifications of the landscape are caused by exogenic processes including eolian activity, mass movement, the growth and retreat of the polar caps, glacial processes and crater-forming impacts. In particular the High Resolution Stereo Camera (HRSC) on board Mars Express (MEx) and the Context Camera (CTX) on board the Mars Reconnaissance Orbiter (MRO) cover large areas at high resolution and thus are particularly well-suited to detect the extent and origin of surface changes on Mars. Multi-temporal observations of variable features on Mars became possible by the increasing number of repeated image acquisitions of the same surface areas. To support the investigation of surface changes that represents a key element in martian research, we developed MUTED, the "Multi-Temporal Database of Planetary Image Data", which is a tool for the identification of the spatial and multi-temporal coverage of planetary image data from Mars. Using MUTED, scientists are able to identify the location, number, and time range of acquisitions of overlapping images from, for example, HRSC and CTX. MUTED also includes images from other planetary datasets such as those of the Mars Orbiter Camera (MOC), the Thermal Emission Imaging System (THEMIS), and the High Resolution Imaging Science Experiment (HiRISE). The database supports the identification and analysis of surface changes and short-lived surface processes on Mars based on fast automatic planetary image database queries. From the multi-temporal planetary image database and investigations based on multi-temporal observations we will better understand the interactions between the surface of Mars and external forces, including the atmosphere. MUTED is available for the planetary scientific community via the webpage of the Institut für Planetologie (IfP) Muenster.

  3. A LOWER INITIAL ABUNDANCE OF SHORT-LIVED {sup 41}Ca IN THE EARLY SOLAR SYSTEM AND ITS IMPLICATIONS FOR SOLAR SYSTEM FORMATION

    SciTech Connect

    Liu, Ming-Chang; Chaussidon, Marc; Srinivasan, Gopalan; McKeegan, Kevin D.

    2012-12-20

    The short-lived radionuclide {sup 41}Ca plays an important role in constraining the immediate astrophysical environment and the formation timescale of the nascent solar system due to its extremely short half-life (0.1 Myr). Nearly 20 years ago, the initial ratio of {sup 41}Ca/{sup 40}Ca in the solar system was determined to be (1.41 {+-} 0.14) Multiplication-Sign 10{sup -8}, primarily based on two Ca-Al-rich Inclusions (CAIs) from the CV chondrite Efremovka. With an advanced analytical technique for isotopic measurements, we reanalyzed the potassium isotopic compositions of the two Efremovka CAIs and inferred the initial ratios of {sup 41}Ca/{sup 40}Ca to be (2.6 {+-} 0.9) Multiplication-Sign 10{sup -9} and (1.4 {+-} 0.6) Multiplication-Sign 10{sup -9} (2{sigma}), a factor of 7-10 lower than the previously inferred value. Considering possible thermal processing that led to lower {sup 26}Al/{sup 27}Al ratios in the two CAIs, we propose that the true solar system initial value of {sup 41}Ca/{sup 40}Ca should have been {approx}4.2 Multiplication-Sign 10{sup -9}. Synchronicity could have existed between {sup 26}Al and {sup 41}Ca, indicating a uniform distribution of the two radionuclides at the time of CAI formation. The new initial {sup 41}Ca abundance is 4-16 times lower than the calculated value for steady-state galactic nucleosynthesis. Therefore, {sup 41}Ca could have originated as part of molecular cloud materials with a free decay time of 0.2-0.4 Myr. Alternative possibilities, such as a last-minute input from a stellar source and early solar system irradiation, could not be definitively ruled out. This underscores the need for more data from diverse CAIs to determine the true astrophysical origin of {sup 41}Ca.

  4. Contributions of short-lived radioiodines to thyroid doses received by evacuees from the Chernobyl area estimated using early in vivo activity measurements.

    PubMed

    Balonov, M; Kaidanovsky, G; Zvonova, I; Kovtun, A; Bouville, A; Luckyanov, N; Voillequé, P

    2003-01-01

    A series of in vivo gamma spectrometric measurements of 65 people evacuated from Pripyat 1.5 days after the Chernobyl Nuclear Power Plant Unit 4 explosion was performed in St Petersburg, Russia, as early as 30 April 1986. The historical spectra and interviews were recently processed and the results used for thyroid dose estimation. Activities of 131I in thyroid and 132Te in lungs were determined easily; for estimation of 132I and 133I activities in thyroid, sophisticated methods of spectral processing were developed. According to thyroid measurement data, the mean ratio of 133I/131I activities (at the time of the accident) inhaled by residents of Pripyat was 2.0. The mean ratio of thyroid dose from 133I inhalation to that caused by 131I amounts to 0.3, which confirms the accuracy of dose estimates based on the evolution of the Chernobyl accident. The mean ratio of 132I activity in thyroid to that of 132Te in lungs was assessed from the human measurement data to be 0.2, which is in reasonable agreement with the metabolic properties of these radionuclides. The mean ratio of thyroid dose from 132I originating from 132Te deposited in lungs to the dose caused by 131I was 0.13 +/- 0.02 for Pripyat residents who did not take KI pills and 0.9 +/- 0.1 for persons who took KI pills. Thus, the contribution of short-lived radioiodines to total thyroid dose of Pripyat residents, which was on average 30% for persons who did not use stable iodine prophylaxis, and about 50% for persons who took KI pills on 26-27 April, should be accounted for in the assessment of thyroid health effects. PMID:14527033

  5. Preliminary Results of IS Plasma Focus as a Breeder of Short-Lived Radioisotopes 12C(d,n)13N

    NASA Astrophysics Data System (ADS)

    Sadat Kiai, S. M.; Elahi, M.; Adlparvar, S.; Shahhoseini, E.; Sheibani, S.; Ranjber akivaj, H.; Alhooie, S.; Safarien, A.; Farhangi, S.; Aghaei, N.; Amini, S.; Khalaj, M. M.; Zirak, A. R.; Dabirzadeh, A. A.; Soleimani, J.; Torkzadeh, F.; Mousazadeh, M. M.; Moradi, K.; Abdollahzadeh, M.; Talaei, A.; Zaeem, A. A.; Moslehi, A.; Kashani, A.; Babazadeh, A. R.; Bagiyan, F.; Ardestani, M.; Roozbahani, A.; Pourbeigi, H.; Tajik Ahmadi, H.; Ahmadifaghih, M. A.; Mahlooji, M. S.; Mortazavi, B. N.; Zahedi, F.

    2011-04-01

    Modified IS (Iranian Sun) plasma focus (10 kJ,15 kV, 94 μF, 0.1 Hz) has been used to produce the short-lived radioisotope 13N (half-life of 9.97 min) through 12C(d,n)13N nuclear reaction. The filling gas was 1.5-3 torr of hydrogen (60%) deuterium (40%) mixture. The target was solid nuclear grade graphite with 5 mm thick, 9 cm width and 13 in length. The activations of the exogenous target on average of 20 shots (only one-third acceptable) through 10-13 kV produced the 511 keV gamma rays. Another peak found at the 570 keV gamma of which both was measured by a NaI portable gamma spectrometer calibrated by a 137Cs 0.25 μCi sealed reference source with its single line at 661.65 keV and 22Na 0.1 μCi at 511 keV. To measure the gamma rays, the graphite target converts to three different phases; solid graphite, powder graphite, and powder graphite in water solution. The later phase approximately has a doubled activity with respect to the solid graphite target up to 0.5 μCi of 511 keV and 1.1 μCi of 570 keV gamma lines were produced. This increment in activity was perhaps due to structural transformation of graphite powder to nano-particles characteristic in liquid water.

  6. Brick Kiln Emissions Quantified with the Aerodyne Mobile Laboratory During the Short Lived Climate Forcing (SLCF) 2013 Campaign in Guanajuato Mexico

    NASA Astrophysics Data System (ADS)

    Fortner, E.; Knighton, W. B.; Herndon, S.; Roscioli, J. R.; Zavala, M.; Onasch, T. B.; Jayne, J. T.; Worsnop, D. R.; Kolb, C. E.; Molina, L. T.

    2013-12-01

    Brick kiln emissions are suspected to be a major source of atmospheric black carbon (BC) in developing countries; and black carbon's role as a short lived climate forcing (SLCF) pollutant is widely recognized. The SLCF-Mexico brick kiln study was conducted from 12-17 March 2013 in Mexico's Guanajuato state. Three different types of brick kilns were investigated (MK2, traditional, and traditional three tier) providing data on the effects of different kiln designs on particle and gas phase emissions. The BC and gaseous combustion emissions from these kilns were measured during both the fire stage and the subsequent smoldering stage with real-time instruments deployed on the Aerodyne Mobile Laboratory, and quantified utilizing flux tracer gases released adjacent to the brick kiln. This method allows examination of the brick kiln plume's evolution as it transits downwind from the source. Particulate measurements conducted by the mobile laboratory included the multi angle absorption photometer (MAAP) to measure black carbon mass, cavity attenuated phase shift (CAPSext) monitor to measure extinction and soot particle aerosol mass spectrometer (SP-AMS) measurements of black carbon. The SP-AMS instrument combines the ability to measure black carbon with the ability to determine the chemical composition of the other particulate matter (PM) components associated with black carbon particles. The variance of PM chemical composition will be examined as a function of burning stage and kiln type and compared to other black carbon PM sources. Gas phase exhaust species measured included CO, CO2, NOx, SO2, CH4, C2H6, as well as a variety of VOCs (acetonitrile, benzene etc.) measured with a PTR-MS instrument. All of these measurements will be examined to construct emission ratios evaluating how these vary with different kiln types and different firing conditions. The evolution of particulate matter and gas phase species as they transit away from the source will also be examined.

  7. 2014 ICHLNRRA intercomparison of radon/thoron gas and radon short-lived decay products measuring instruments in the NRPI Prague.

    PubMed

    Jílek, K; Timková, J

    2015-06-01

    During the Eighth International Conference on High Levels of Natural Radiation and Radon Areas held in autumn 2014 at Prague, the third intercomparison of radon/thoron gas and radon short-lived decay products measurement instruments was organised by and held at the Natural Radiation Division of the National Radiation Protection Institute (NRPI; SÚRO v.v.i.) in Prague. The intercomparison was newly focussed also on continuous monitors with active sampling adapters capable to distinguish radon/thoron gas in their mix field.The results of radon gas measurements carried out in the big NRPI radon chamber indicated very well an average deviation of up to 5 % from the reference NRPI value for 80 % of all the exposed instruments. The results of equilibrium equivalent concentration continuous monitors indicated an average deviation of up to 5 % from the reference NRPI value for 40 % of all the exposed instruments and their ~8-10 % shift compared with the NRPI. The results of investigated ambient conditions upon response of exposed continuous monitors indicated influence of aerosol changes upon response of radon monitors with an active air sampling adapters through the filter, only. The exposures of both radon/thoron gas discriminative continuous monitors and passive detectors have been indicated inconsistent results: on one hand, their excellent agreement up to several per cent for both the gases, and on the other hand, systematic unsatisfactory differences up to 40 %. Additional radon/thoron exercises are recommended to improve both the instruments themselves and quality of their operators. PMID:25990114

  8. TRIGGERING COLLAPSE OF THE PRESOLAR DENSE CLOUD CORE AND INJECTING SHORT-LIVED RADIOISOTOPES WITH A SHOCK WAVE. II. VARIED SHOCK WAVE AND CLOUD CORE PARAMETERS

    SciTech Connect

    Boss, Alan P.; Keiser, Sandra A. E-mail: keiser@dtm.ciw.edu

    2013-06-10

    A variety of stellar sources have been proposed for the origin of the short-lived radioisotopes that existed at the time of the formation of the earliest solar system solids, including Type II supernovae (SNe), asymptotic giant branch (AGB) and super-AGB stars, and Wolf-Rayet star winds. Our previous adaptive mesh hydrodynamics models with the FLASH2.5 code have shown which combinations of shock wave parameters are able to simultaneously trigger the gravitational collapse of a target dense cloud core and inject significant amounts of shock wave gas and dust, showing that thin SN shocks may be uniquely suited for the task. However, recent meteoritical studies have weakened the case for a direct SN injection to the presolar cloud, motivating us to re-examine a wider range of shock wave and cloud core parameters, including rotation, in order to better estimate the injection efficiencies for a variety of stellar sources. We find that SN shocks remain as the most promising stellar source, though planetary nebulae resulting from AGB star evolution cannot be conclusively ruled out. Wolf-Rayet (WR) star winds, however, are likely to lead to cloud core shredding, rather than to collapse. Injection efficiencies can be increased when the cloud is rotating about an axis aligned with the direction of the shock wave, by as much as a factor of {approx}10. The amount of gas and dust accreted from the post-shock wind can exceed that injected from the shock wave, with implications for the isotopic abundances expected for a SN source.

  9. RNA-seq of the aging brain in the short-lived fish N. furzeri - conserved pathways and novel genes associated with neurogenesis.

    PubMed

    Baumgart, Mario; Groth, Marco; Priebe, Steffen; Savino, Aurora; Testa, Giovanna; Dix, Andreas; Ripa, Roberto; Spallotta, Francesco; Gaetano, Carlo; Ori, Michela; Terzibasi Tozzini, Eva; Guthke, Reinhard; Platzer, Matthias; Cellerino, Alessandro

    2014-12-01

    The brains of teleost fish show extensive adult neurogenesis and neuronal regeneration. The patterns of gene regulation during fish brain aging are unknown. The short-lived teleost fish Nothobranchius furzeri shows markers of brain aging including reduced learning performances, gliosis, and reduced adult neurogenesis. We used RNA-seq to quantify genome-wide transcript regulation and sampled five different time points to characterize whole-genome transcript regulation during brain aging of N. furzeri. Comparison with human datasets revealed conserved up-regulation of ribosome, lysosome, and complement activation and conserved down-regulation of synapse, mitochondrion, proteasome, and spliceosome. Down-regulated genes differ in their temporal profiles: neurogenesis and extracellular matrix genes showed rapid decay, synaptic and axonal genes a progressive decay. A substantial proportion of differentially expressed genes (~40%) showed inversion of their temporal profiles in the last time point: spliceosome and proteasome showed initial down-regulation and stress-response genes initial up-regulation. Extensive regulation was detected for chromatin remodelers of the DNMT and CBX families as well as members of the polycomb complex and was mirrored by an up-regulation of the H3K27me3 epigenetic mark. Network analysis showed extensive coregulation of cell cycle/DNA synthesis genes with the uncharacterized zinc-finger protein ZNF367 as central hub. In situ hybridization showed that ZNF367 is expressed in neuronal stem cell niches of both embryonic zebrafish and adult N. furzeri. Other genes down-regulated with age, not previously associated with adult neurogenesis and with similar patterns of expression are AGR2, DNMT3A, KRCP, MEX3A, SCML4, and CBX1. CBX7, on the other hand, was up-regulated with age. PMID:25059688

  10. FORMATION OF THE SHORT-LIVED RADIONUCLIDE {sup 36}Cl IN THE PROTOPLANETARY DISK DURING LATE-STAGE IRRADIATION OF A VOLATILE-RICH RESERVOIR

    SciTech Connect

    Jacobsen, Benjamin; Yin Qingzhu; Matzel, Jennifer; Hutcheon, Ian D.; Ramon, Erick C.; Weber, Peter K.; Krot, Alexander N.; Nagashima, Kazuhide; Ishii, Hope A.; Ciesla, Fred J.

    2011-04-20

    Short-lived radionuclides (SLRs) in the early solar system provide fundamental insight into protoplanetary disk evolution. We measured the {sup 36}Cl-{sup 36}S-isotope abundance in wadalite (<15 {mu}m), a secondary chlorine-bearing mineral found in calcium-aluminum-rich inclusions (CAIs) in the Allende CV chondrite, to decipher the origin of the SLR {sup 36}Cl ({tau}{sub 1/2} {approx} 3 x 10{sup 5} yr) in the early solar system. Its presence, initial abundance, and the noticeable decoupling from {sup 26}Al raise serious questions about the origin of SLRs. The inferred initial {sup 36}Cl abundance for wadalite, corresponding to a {sup 36}Cl/{sup 35}Cl ratio of (1.81 {+-} 0.13) x 10{sup -5}, is the highest {sup 36}Cl abundance ever reported in any early solar system material. The high level of {sup 36}Cl in wadalite and the absence of {sup 26}Al ({sup 26}Al/{sup 27}Al {<=} 3.9 x 10{sup -6}) in co-existing grossular (1) unequivocally support the production of {sup 36}Cl by late-stage solar energetic particle irradiation in the protoplanetary disk and (2) indicates that the production of {sup 36}Cl, recorded by wadalite, is unrelated to the origin of {sup 26}Al and other SLRs ({sup 10}Be, {sup 53}Mn) recorded by primary minerals of CAIs and chondrules. We infer that {sup 36}Cl was largely produced by irradiation of a volatile-rich reservoir in an optically thin protoplanetary disk adjacent to the region in which the CV chondrite parent asteroid accreted while the Sun was a weak T Tauri star. Subsequently, {sup 36}Cl accreted into the Allende CV chondrite together with condensed water ices.

  11. Stepwise Catalytic Mechanism via Short-Lived Intermediate Inferred from Combined QM/MM MERP and PES Calculations on Retaining Glycosyltransferase ppGalNAcT2

    PubMed Central

    Trnka, Tomáš; Kozmon, Stanislav; Tvaroška, Igor; Koča, Jaroslav

    2015-01-01

    The glycosylation of cell surface proteins plays a crucial role in a multitude of biological processes, such as cell adhesion and recognition. To understand the process of protein glycosylation, the reaction mechanisms of the participating enzymes need to be known. However, the reaction mechanism of retaining glycosyltransferases has not yet been sufficiently explained. Here we investigated the catalytic mechanism of human isoform 2 of the retaining glycosyltransferase polypeptide UDP-GalNAc transferase by coupling two different QM/MM-based approaches, namely a potential energy surface scan in two distance difference dimensions and a minimum energy reaction path optimisation using the Nudged Elastic Band method. Potential energy scan studies often suffer from inadequate sampling of reactive processes due to a predefined scan coordinate system. At the same time, path optimisation methods enable the sampling of a virtually unlimited number of dimensions, but their results cannot be unambiguously interpreted without knowledge of the potential energy surface. By combining these methods, we have been able to eliminate the most significant sources of potential errors inherent to each of these approaches. The structural model is based on the crystal structure of human isoform 2. In the QM/MM method, the QM region consists of 275 atoms, the remaining 5776 atoms were in the MM region. We found that ppGalNAcT2 catalyzes a same-face nucleophilic substitution with internal return (SNi). The optimized transition state for the reaction is 13.8 kcal/mol higher in energy than the reactant while the energy of the product complex is 6.7 kcal/mol lower. During the process of nucleophilic attack, a proton is synchronously transferred to the leaving phosphate. The presence of a short-lived metastable oxocarbenium intermediate is likely, as indicated by the reaction energy profiles obtained using high-level density functionals. PMID:25849117

  12. The regulated degradation of 3-hydroxy-3-methylglutaryl-CoA reductase requires a short-lived protein and occurs in the endoplasmic reticulum.

    PubMed

    Chun, K T; Bar-Nun, S; Simoni, R D

    1990-12-15

    A chimeric gene consisting of the coding sequence for the membrane domain of the endoplasmic reticulum protein, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, fused to the coding sequence for the soluble enzyme, beta-galactosidase of Escherichia coli, has been previously constructed. This fusion protein, HMGal, has been localized to the membrane of the endoplasmic reticulum of Chinese hamster ovary cells transfected with this chimeric gene, and its beta-galactosidase activity has declined in the presence of low density lipoprotein (Skalnik, D. G., Narita, H., Kent, C., and Simoni, R. D. (1988) J. Biol. Chem. 263, 6836-6841). In this report, we demonstrate that the loss of beta-galactosidase activity results from the accelerated degradation of the HMGal protein. Taking advantage of a fluorescence-activated cell sorter technique, we have selected transfected cells which express sufficient levels of HMGal to improve its immunodetection. Based on pulse-chase experiments, the half-life of HMGal is 6.0 h, and, in the presence of 20 mM mevalonate, the half-life declines 1.7-fold. Under these conditions, mevalonate accelerates the degradation of HMG-CoA reductase in these cells 1.6-fold, from 8.4 h to 5.3 h, most probably by the same mechanism. This mevalonate-regulated degradation of HMGal is not due to a heteromeric association of HMGal with reductase, since the same effect has been observed in cells lacking the reductase protein. In addition, we demonstrate that inhibition of protein synthesis with cycloheximide abolishes the mevalonate-dependent accelerated degradation of HMGal, in agreement with previous studies which have presented indirect evidence that a short-lived protein is essential for mediating the loss of HMG-CoA reductase activity. Finally, using brefeldin A, we show that the mevalonate-dependent accelerated degradation of HMGal may occur in the endoplasmic reticulum. PMID:2254343

  13. Stepwise catalytic mechanism via short-lived intermediate inferred from combined QM/MM MERP and PES calculations on retaining glycosyltransferase ppGalNAcT2.

    PubMed

    Trnka, Tomáš; Kozmon, Stanislav; Tvaroška, Igor; Koča, Jaroslav

    2015-04-01

    The glycosylation of cell surface proteins plays a crucial role in a multitude of biological processes, such as cell adhesion and recognition. To understand the process of protein glycosylation, the reaction mechanisms of the participating enzymes need to be known. However, the reaction mechanism of retaining glycosyltransferases has not yet been sufficiently explained. Here we investigated the catalytic mechanism of human isoform 2 of the retaining glycosyltransferase polypeptide UDP-GalNAc transferase by coupling two different QM/MM-based approaches, namely a potential energy surface scan in two distance difference dimensions and a minimum energy reaction path optimisation using the Nudged Elastic Band method. Potential energy scan studies often suffer from inadequate sampling of reactive processes due to a predefined scan coordinate system. At the same time, path optimisation methods enable the sampling of a virtually unlimited number of dimensions, but their results cannot be unambiguously interpreted without knowledge of the potential energy surface. By combining these methods, we have been able to eliminate the most significant sources of potential errors inherent to each of these approaches. The structural model is based on the crystal structure of human isoform 2. In the QM/MM method, the QM region consists of 275 atoms, the remaining 5776 atoms were in the MM region. We found that ppGalNAcT2 catalyzes a same-face nucleophilic substitution with internal return (SNi). The optimized transition state for the reaction is 13.8 kcal/mol higher in energy than the reactant while the energy of the product complex is 6.7 kcal/mol lower. During the process of nucleophilic attack, a proton is synchronously transferred to the leaving phosphate. The presence of a short-lived metastable oxocarbenium intermediate is likely, as indicated by the reaction energy profiles obtained using high-level density functionals. PMID:25849117

  14. IL-2 induction of Blimp-1 is a key in vivo signal for CD8+ short-lived effector T cell differentiation.

    PubMed

    Boulet, Salix; Daudelin, Jean-Franois; Labrecque, Nathalie

    2014-08-15

    During infection or vaccination, only a small proportion of CD8(+) T cells differentiate into memory cells. The mechanisms underlying the differentiation of CD8(+) T cells into short-lived effector cells (SLECs) or memory precursor effector cells are poorly defined. It was recently shown in infectious models that the transcriptional repressor B lymphocyte-induced maturation protein 1 (Blimp-1) enhances the formation of SLECs. The factors controlling Blimp-1 expression leading to the in vivo formation of SLECs are still not known. However, it has been shown that cytokines such as IL-2 induce Blimp-1 expression in vitro. In this study, we took advantage of the low-inflammation model of dendritic cell immunization to study the role of the IL-2/Blimp-1 axis in SLEC differentiation as well as the importance of Blimp-1 expression in memory precursor effector cells for proper CD8(+) memory generation. Our results show that Blimp-1 deficiency affects effector differentiation and function in the absence of inflammation. Unexpectedly, memory generation was not affected in Blimp-1-deficient OT-I cells responding to vaccination. In addition, modulation of the bioavailability of IL-2 by injection either of a blocking Ab or of the cytokine, demonstrates a link between IL-2, Blimp-1 induction, and SLEC formation in wild-type cells. Conversely, injection of IL-2 had less effect on Blimp-1-deficient CD8(+) T cells, indicating that the effect of IL-2 on in vivo SLEC differentiation is mediated by Blimp-1. In conclusion, IL-2 induction of Blimp-1 expression is a key regulator of SLEC differentiation in vivo. PMID:25015830

  15. Time-series variations of the short-lived Ra in coastal waters: implying input of SGD to the coastal zone of Da-Chia River, Taichung, Taiwan

    NASA Astrophysics Data System (ADS)

    Hsu, Feng-Hsin; Su, Chih-Chieh; Lin, In-Tain; Huh, Chih-An

    2015-04-01

    Submarine groundwater discharge (SGD) has been recognized as an important pathway for materials exchanging between land and sea. Input of SGD carries the associated nutrients, trace metals, and inorganic carbon that may makes great impacts on ecosystem in the coastal zone. Due to the variability of SGD magnitude, it is difficult to estimate the flux of those associated materials around the world. Even in the same area, SGD magnitude also varies in response to tide fluctuation and seasonal change on hydraulic gradient. Thus, long-term investigation is in need. In Taiwan, the SGD study is rare and the intrusion of seawater in the coastal aquifer is emphasized in previous studies. According to the information from Hydrogeological Data Bank (Central Geological Survey, MOEA), some areas still show potentiality of SGD. Here, we report the preliminary investigation result of SGD at Gaomei Wildlife Conservation Area which located at the south of the Da-Chia River mouth. This study area is characterized by a great tidal rang and a shallow aquifer with high groundwater recharge rate. Time-series measurement of the short-lived Ra in surface water was done in both dry and wet seasons at a tidal flat site and shows different trends of excess Ra-224 between dry and wet seasons. High excess Ra-224 activities (>20 dpm/100L) occurred at high tide in dry season but at low tide in wet season. The plot of salinity versus excess Ra-224, showing non-conservative curve, suggests that high excess Ra-224 activities derive from desorption in dry season but from SGD input in wet season.

  16. Voltammetric investigation of DNA damage induced by nitrofurazone and short-lived nitro-radicals with the use of an electrochemical DNA biosensor.

    PubMed

    Ni, Yongnian; Wang, Pingping; Kokot, Serge

    2012-01-01

    Electrochemical behavior of nitrofurazone (NFZ) was investigated with the use of cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The pH-dependence of NFZ was studied at a glassy carbon electrode (GCE) in ethanol/Britton-Robinson buffer (30:70), and short-lived nitro-radicals were generated by the reduction of NFZ at high pHs (>7.0). In the presence of DNA, the DPV peak current of NFZ decreased and the peak potential shifted negatively, which indicated that there was an electrostatic interaction between NFZ and DNA. An electrochemical dsDNA/GCE biosensor was prepared to study the DNA damage produced in the presence NFZ; this process was followed with the use of the Co(phen)(3)(2+) electroactive probe. Also, the oxidation peaks of guanosine (750 mV) and adenosine (980 mV) indicated that DNA damage was related directly to the nitro-radicals. Experiments demonstrated that DNA damage occurred via two different steps while NFZ was metabolized and nitro-radicals were produced. Novel work with AFM on the NFZ/DNA interaction supported the suggestion that in vivo, the nitro-radicals were more cytotoxic than the NFZ molecules. A linear DPV calibration plot was obtained for NFZ analysis at a modified dsDNA/GCE (concentration range: 2.50 × 10(-6)-3.75 × 10(-5) mol L(-1); limit of detection: 8.0 × 10(-7) mol L(-1)), and NFZ was determined successfully in pharmaceutical samples. PMID:22717476

  17. Understanding the radiative impact of decadal trends in Short-Lived climate forcers over the Arctic troposphere: A significant role for non-BC species

    NASA Astrophysics Data System (ADS)

    Breider, T. J.; Mickley, L. J.; Jacob, D. J.; Fisher, J. A.; Wang, Q.; Koplitz, S. N.; Yantosca, R. M.

    2012-12-01

    Over recent decades the Arctic has experienced a period of rapid warming. Current general circulation models (GCMs) generally have difficulty reproducing the observed warming and sea ice loss. A possible explanation is the inadequate representation of Short Lived (SL) species (Aerosols and Ozone). In this work we have developed a model capable of providing a state-of-the-science estimate of multi-decadal trends in Arctic climate forcing from SL species. The model has been extensively tested against observations from the International Polar Year (IPY) in 2007-2008. We will present key findings from a simulation for 2008 using GEOS-Chem, followed by results from a 1980-2010 simulation assessing the impact of decadal trends in SL species. Our results indicate a large contribution from non-black carbon (BC) components to the spring-summer Arctic absorption aerosol optical depth (AAOD) and deposition of absorbing aerosol to the snowpack. We find organic carbon (OC) contributes 17% of spring-summer Arctic AAOD and 16% of the deposition to the snowpack. Dust is important during the spring (11% of Arctic AAOD and 25% of snowpack deposition). Source attribution shows the Sahara is a major source of Arctic dust indicating transport over Northern Europe is an important pathway of dust to the Arctic. Our results show the observed shift in the Arctic sulfate size distribution between spring and summer is key to reproducing the summertime aerosol optical depth (AOD) observations at Arctic AERONET stations. We also quantify the contribution of anthropogenic and open fires sources. For Arctic ozone, we find the anthropogenic influence is largest in the spring, increasing natural troposphere ozone by 46%. In the spring and summer, anthropogenic sources contribute 40% of Arctic AAOD, 26% of the absorbing mass deposited to the snowpack and 40% of the Arctic AOD. Our results emphasize the importance of open fires (agricultural and natural) as a source of SL species to the Arctic and a potential driver of change in the region. We will also quantify the radiative forcing from SL species in this work using the GISS model. Finally, we will show the first results from the 1980-2010 simulation assessing the contribution of SL species to Arctic climate forcing during this period.

  18. Formation of short-lived radionuclides in the protoplanetary disk during late-stage irradiation of a volatile-rich reservoir

    SciTech Connect

    Jacobsen, B; Matzel, J; Hutcheon, I D; Krot, A N; Yin, Q -; Nagashima, K; Ramon, E; Weber, P; Ishii, H; Ciesla, F

    2010-11-30

    The origin of short-lived (t{sub 1/2} < 5 Myr) and now extinct radionuclides ({sup 10}Be, {sup 26}Al, {sup 36}Cl, {sup 41}Ca, {sup 53}Mn, {sup 60}Fe; hereafter SLRs) is fundamental to understanding the formation of the early solar system. Two distinct classes of models have been proposed to explain the origin of SLRs: (1) injection from a nearby stellar source (e.g., supernova, asymptotic giant branch star or Wolf-Rayet star) and (2) solar energetic particle irradiation of dust and gas near the proto-Sun. Recent studies have demonstrated that {sup 36}Cl was extant in the early solar system. However, its presence, initial abundance and the noticeable decoupling from {sup 26}Al raise serious questions about the origin of SLRs. Here we report {sup 36}Cl-{sup 36}S and {sup 26}Al-{sup 26}Mg systematics for wadalite and grossular, secondary minerals in a calcium-aluminum-rich inclusion (CAI) from the CV chondrite Allende that allow us to reassess the origin of SLRs. The inferred abundance of {sup 36}Cl in wadalite, corresponding to a {sup 36}Cl/{sup 35}Cl ratio of (1.81 {+-} 0.13) x 10{sup -5}, is the highest {sup 36}Cl abundance reported in any early solar system material. The high level of {sup 36}Cl in wadalite and the absence of {sup 26}Al ({sup 26}Al/{sup 27}Al {le} 3.9 x 10{sup -6}) in co-existing grossular indicates that (1) {sup 36}Cl formed by late-stage solar energetic particle irradiation and (2) the production of {sup 36}Cl, recorded by secondary minerals, is unrelated to the origin of {sup 26}Al and other SLRs ({sup 10}Be, {sup 53}Mn) recorded by primary minerals of CAIs and chondrules. We conclude that 36Cl was produced by solar energetic particle irradiation of a volatile-rich reservoir in an optically thin protoplanetary disk adjacent to the accretion region of the CV chondrite parent asteroid.

  19. Tracing historical tropical cyclones and the 1883 Krakatoa tsunami in short-lived geological archives of the Ashburton Delta (NW Australia)

    NASA Astrophysics Data System (ADS)

    May, Simon Matthias; Brill, Dominik; Engel, Max; Scheffers, Anja; Pint, Anna; Wennrich, Volker; Squire, Peter; Kelletat, Dieter; Brückner, Helmut

    2014-05-01

    Records of coastal geological archives are discontinuous. They store traces of both episodic and long-term processes as particular depositional landforms, deposits or erosional features. In particular the identification and interpretation of episodic high-energy coastal flooding due to tropical cyclones (TCs) and tsunamis is associated with a number of difficulties, including the spatial and temporal variability of geological records as well as the application of different dating techniques. In addition, the differentiation between tsunami and storm deposits remains challenging, notably where modern deposits and/or historical reports on the event are absent. Analysing modern (or historic) analogues for which documentation of process-specific parameters and/or geomorphic and sedimentary effects are available contributes to a better understanding of their sedimentary signatures and related depositional processes. These studies are key components to unravel the fossil record and the history of past events. The NW coast of Western Australia (WA) is highly vulnerable to extreme wave events. On average 1-2 TCs impact the W Australian coast per year, and ten historically documented tsunami events are recorded since 1858, including the tsunami following the 1883 Krakatoa eruption. However, no sedimentary evidence on this particular event has been presented yet, and little is known about the geological imprint of both (pre)historic TCs and tsunamis in NW Australia in general. Here we present new data on the sedimentology and chronostratigraphy of historical washover events found in short-lived geological archives of the Ashburton River delta (NW part of Western Australia), where clearly distinguishable traces of both TCs and the 1883 Krakatoa tsunami are recorded. We aim at (i) establishing (at least locally valid) sedimentary criteria differentiating between TCs and tsunami deposits; (ii) presenting an OSL-based local chronostratigraphy with direct relation to historical events; and (iii) discussing the archive's overall significance for palaeoevent research. Our results show that the presented archive is discontinuous on different spatial and temporal levels, related to the episodic nature of extreme wave events and the general variability of geological archives.

  20. Linking early Earth magma ocean crystallization and overturn with observed large low-shear-velocity provinces (LLSVPs) and short-lived radioisotopic measurements in Archean rocks

    NASA Astrophysics Data System (ADS)

    Brown, S. M.; Elkins-Tanton, L. T.; Walker, R. J.

    2013-12-01

    Motivated by the well-characterized discrepancy between measurements of 142Nd in chondrites and those in Earth rocks (e.g.,[1][2]) in addition to recent measurements of Archean rocks with anomalous 142Nd and 182W (e.g.,[3][4][5]), we model the crystallization and overturn of a terrestrial chondritic magma ocean, and track the isotopic reservoirs that may result. Following magma ocean solidification, solid-state overturn occurs because solidification produces a gravitationally unstable configuration where the last cumulates to solidify are densest and also enriched in incompatible elements. As suggested by [1][2], these originally shallow cumulates that, following overturn, would now reside near the core-mantle boundary are tantalizing targets for the hypothesized hidden reservoir(s) of incompatible elements. These last, dense, enriched cumulates may have evolved negative 142Nd and 182W isotopic anomalies, while cumulates that form earlier and deeper in the magma ocean would likely be poor in incompatible elements and have evolved complementary positive isotopic anomalies. Because crystal - liquid partition coefficients of Sm, Nd, Hf, and W in nucleating mantle phases are poorly constrained and vary over orders of magnitude, we use a Monte Carlo approach to cover the parameter space of reported partition coefficients. Although data are limited, Archean rocks appear to show a non-linear trend between age and 142Nd and 182W, suggesting inefficient heterogeneous mixing of some of the early enriched reservoir (EER or late stage cumulates) back into the early depleted reservoir (EDR or deeper cumulates) during or after overturn, also first suggested by [1][2]. To account for this, we model various mixing scenarios using post-overturn mantle stratigraphy. Additionally, because 142Nd and 182W are decay products of short-lived radioisotopes, the timing of magma ocean crystallization is critical to producing a modern day mantle consistent with measured compositions. We therefore iterate through time to determine the statistically most likely time of the last major mantle-melting event. Consistent with [2], we argue that the EER is not hidden but is instead the seismologically observed large low-shear-velocity provinces (LLSVPs), or the D'' region, and the ultra low velocity zones (ULVZs) are dense, iron-rich silicon-poor melts of the LLSVPs. Given this, the isotopic reservoirs produced by our models must mix such that the EER remaining after mixing is the same volume as the LLSVPs, or 2% of the mantle (e.g., [6][7]). Approximately two-thirds our run results are "successful" given known partition coefficients, and so our results suggest that this model is viable: magma ocean fractional solidification can produce mantle reservoirs consistent with isotopic compositions observed in some rocks, and can produce a dense lower mantle layer consistent in longevity and volume to the LLSVPs. [1]Boyet and Carlson,2005,Science,309(5743),576-81.[2]Carlson and Boyet,2008,Phil. Trans. R. Soc. A,366(1883),4077-103. [3]Willbold et al.,2011,Nature,477(7363), 195-8. [4]Touboul et al.,2012,Science,335(6072),1065-9. [5]Rizo et al.,Nature,491(7422),96-100. [6]Burke et al.,2008,EPSL,265(1-2),49-60. [7]Hernlund and Houser,2008,EPSL,265(3-4),423-37.

  1. Transfer time and source tracing in the soil - water- -plant system deciphered by the U-and Th-series short-lived nuclides

    NASA Astrophysics Data System (ADS)

    Rihs, S.; Pierret, M.; Chabaux, F.

    2011-12-01

    Because soils form at the critical interface between the lithosphere and the atmosphere, characterization of the dynamics occurring through this compartment represents an important goal for several scientific fields and/or human activities. However, this issue remains a challenge because soils are complex systems, where a continuous evolution of minerals and organic soil constituents occurs in response to interactions with waters and vegetation. This study aims to investigate the relevance of short-lived nuclides of U- and Th-series to quantify the transfer times and scheme of radionuclides through a soil - water - plant ecosystem. Activities of (226Ra), (228Ra) and (228Th), as well as the long-lived (232Th), were measured by TIMS and gamma-spectrometry in the major compartments of a forested soil section, i.e.: solid soil fractions (exchangeable fraction, secondary phases and inherited primary minerals), waters (seepage soil waters and a spring further down the watershed) and vegetation (fine and coarse roots of beech trees, young and mature leaves). The matching of these nuclides half-live to bio-geochemical processes time-scale and the relatively good chemical analogy of radium with calcium make these isotopes especially suitable to investigate either time or mechanism of transfers within a soil-water-plant system. Indeed, the (228Ra/226Ra) isotopic ratios strongly differ in the range of samples, allowing quantifying the source and duration transfers. Analyses of the various solid soil fractions demonstrate a full redistribution of Ra isotopes between the inherited minerals and secondary soil phases. However, the transfer of these isotopes to the seepage water or to the tree roots does not follow a simple and obvious scheme. Both primary and secondary phases show to contribute to the dissolved radium. However, depending on the season, the tree leaves degradation also produces up to 70% of dissolved radium. Immobilization of a large part of this radium occurs within the first 70cm of the soil layer, either by plant uptake, or adsorption/ precipitation in particular soil layers. Consistently, the Ra isotope ratio in the spring water is similar to the inherited primary soil fraction, suggesting a "deep" (i.e. below the shallow 70cm of soil layer) origin of the exported dissolved radium and the short-scale effect of vegetation cycling onto radium transfer. The radium isotopic ratio in the trees roots does not match the soil exchangeable fraction, nor the seepage waters, but rather the bulk soil, suggesting a large and mixed pool of radium for roots uptake. Decay of 228Ra within the various parts of the trees allows calculating a vegetation cycling duration of about 10 years for this nuclide. Finally an unexpected large amount of unsupported 228Th in the tree leaves can only be explained by a preferential migration of the 228Ac (228Th precursor). The very short life of this nuclide allows therefore assessing that such transport from roots and deposition within stem and leaves take place within 30 hours at the most.

  2. Oxygen isotopic and geochemical evidence for a short-lived, high-temperature hydrothermal event in the Chegem caldera, Caucasus Mountains, Russia

    NASA Astrophysics Data System (ADS)

    Gazis, Carey; Taylor, Hugh P.; Hon, Ken; Tsvetkov, Andrei

    1996-10-01

    Within the 2.8 Ma Chegem ash-flow caldera (11 15 km), a single cooling unit of rhyolitic to dacitic welded tuff more than 2 km thick is exposed in deep valleys incised during recent rapid uplift of the Caucasus Mountains. The intracaldera tuff is mineralogically fresh and unaltered, and is overlain by andesite lavas and cut by a resurgent granodiorite intrusion. Major- and trace-element compositions for a 1405-m stratigraphic section of intracaldera tuff display trends of upwardly increasing Na 2O, CaO, A1 2O 3, total Fe, MgO, TiO 2, Sr and Zr and decreasing SiO 2, K 2O and Rb. This mafic-upward zoning (from 76.1 to 69.9% SiO 2) reflects an inverted view of the upper part of the source magma chamber. Oxygen isotope studies of 35 samples from this 1405-m section define a striking profile with "normal" igneous ?18O values (+7.0 to +8.5) in the lower 600 m of tuff, much lower ?18O values (-4.0 to +4.3) in a 700-m zone above that and a shift to high ?18O values (+4.4 to +10.9) in the upper 100 m of caldera-fill exposure. Data from two other partial stratigraphic sections indicate that these oxygen isotope systematics are probably a caldera-wide phenomenon. Quartz and feldspar phenocrysts everywhere have "normal" igneous ?18O values of about +8.5 and +7.5, respectively, whereas groundmass and glass ?18O values range from -7.7 to +12.3. Consequently, the ?18O values of coexisting feldspar, groundmass and glass form a steep array in a plot of ?feldspar vs. ?groundmss/glass. Such pronounced disequilibrium between coexisting feldspar and groundmass or glass has never before been observed on this scale. It requires a hydrothermal event involving large amounts of low- 18O H 2O at sufficiently high temperatures and short enough time (tens of years or less) that glass exchanges thoroughly but feldspar does not. The most likely process responsible for the 18O depletions at Chegem is a very high temperature (500-600 C), short-lived, vigorous meteoric-hydrothermal event that was focused within the upper 750 m of intracaldera tuff. Mass balance calculations indicate fluid fluxes of ? 6 10 -6 molcm -2 s -1. We believe that the closest historical analogue to this Chegem hydrothermal event is the situation observed in the Valley of Ten Thousand Smokes (Alaska, USA), where hundreds of steam fumaroles with measured temperatures as high as 645 C persisted for 10 to 15 years in the much smaller welded ash-flow tuff sheet (? 200 m thick) produced by the 1912 Katmai eruption.

  3. Oxygen isotopic and geochemical evidence for a short-lived, high-temperature hydrothermal event in the Chegem caldera, Caucasus Mountains, Russia

    USGS Publications Warehouse

    Gazis, C.; Taylor, H.P., Jr.; Hon, K.; Tsvetkov, A.

    1996-01-01

    Within the 2.8 Ma Chegem ash-flow caldera (11 ?? 15 km), a single cooling unit of rhyolitic to dacitic welded tuff more than 2 km thick is exposed in deep valleys incised during recent rapid uplift of the Caucasus Mountains. The intracaldera tuff is mineralogically fresh and unaltered, and is overlain by andesite lavas and cut by a resurgent granodiorite intrusion. Major- and trace-element compositions for a 1405-m stratigraphic section of intracaldera tuff display trends of upwardly increasing Na2O, CaO, Al2O3, total Fe, MgO, TiO2, Sr and Zr and decreasing SiO2, K2O and Rb. This mafic-upward zoning (from 76.1 to 69.9% SiO2) reflects an inverted view of the upper part of the source magma chamber. Oxygen isotope studies of 35 samples from this 1405-m section define a striking profile with "normal" igneous ??18O values (+7.0 to +8.5) in the lower 600 m of tuff, much lower ??18O values (-4.0 to +4.3) in a 700-m zone above that and a shift to high ??18O values (+4.4 to -10.9) in the upper 100 m of caldera-fill exposure. Data from two other partial stratigraphic sections indicate that these oxygen isotope systematics are probably a caldera-wide phenomenon. Quartz and feldspar phenocrysts everywhere have "normal" igneous ??18O values of about +8.5 and +7.5, respectively, whereas groundmass and glass ??18O values range from -7.7 to +12.3. Consequently, the ??18O values of coexisting feldspar, groundmass and glass form a steep array in a plot of ??feldspar vs. ??groundmass/glass. Such pronounced disequilibrium between coexisting feldspar and groundmass or glass has never before been observed on this scale. It requires a hydrothermal event involving large amounts of low-18O H2O at sufficiently high temperatures and short enough time (tens of years or less) that glass exchanges thoroughly but feldspar does not. The most likely process responsible for the O depletions at Chegem is a very high temperature (500-600??C), short-lived, vigorous meteoric-hydrothermal event that was focused within the upper 750 m of intracaldera tuff. Mass balance calculations indicate fluid fluxes of = 6 ?? 10-6 mol cm-2 s-1. We believe that the closest historical analogue to this Chegem hydrothermal event is the situation observed in the Valley of Ten Thousand Smokes (Alaska, USA), where hundreds of steam fumaroles with measured temperatures as high as 645??C persisted for 10 to 15 years in the much smaller welded ash-flow tuff sheet (??? 200 m thick) produced by the 1912 Katmai eruption.

  4. Heavy element abundances in Ap stars from ultraviolet data. I - The bright reference stars Alpha Lyrae and Alpha Canis Majoris A

    NASA Technical Reports Server (NTRS)

    Boiarchuk, A. A.; Snow, T. P., Jr.

    1978-01-01

    Curve-of-growth analysis is used to derive chemical abundances in Alpha Lyr and Alpha CMa, based on ultraviolet spectra obtained with Copernicus. This analysis is part of a program to study the abundances of the heavy elements mercury and platinum and the short-lived element technetium in the atmospheres of Ap and Am stars. Ultraviolet Fe II lines are used to establish the curves of growth for Alpha Lyr and Alpha CMa A; abundances of a variety of elements, along with upper limits on Hg, Pt, and Tc, are derived. In cases where previous studies based on visual spectra have included elements in common with the present analysis, the agreement is good within the known uncertainties. One new element, cadmium, is observed for these two stars. The upper limits on Pt and Hg, as well as Tc, show that these elements are probably not enhanced in Alpha CMa A by more than about one order of magnitude.

  5. {alpha} decay of the new isotope {sup 206}Ac

    SciTech Connect

    Eskola, K.; Kuusiniemi, P.; Leino, M.; Cocks, J.F.; Enqvist, T.; Hurskanen, S.; Kettunen, H.; Trzaska, W.H.; Uusitalo, J.; Allatt, R.G.; Greenlees, P.T.; Page, R.D.

    1998-01-01

    The new neutron-deficient nuclide {sup 206}Ac was produced by bombarding a {sup 175}Lu target with 5.5 MeV/nucleon {sup 36}Ar ions. The evaporation residues were separated in flight by a gas-filled separator and subsequently identified by the {alpha}-{alpha} position and time correlation method. {sup 206}Ac was found to have two {alpha} particle emitting isomeric levels with half-lives of (22{sub {minus}5}{sup +9}) ms and (33{sub {minus}9}{sup +22}) ms, and with {alpha} particle energies of (7790{plus_minus}30) keV and (7750{plus_minus}20) keV, respectively. The former isomer is tentatively assigned to a J{sup {pi}}=3{sup +} level and the latter to a J{sup {pi}}=10{sup {minus}} level, both of which are also seen in the daughter and granddaughter nuclides {sup 202}Fr and {sup 198}At. Improved values of (27{sub {minus}6}{sup +11}) ms and (7693{plus_minus}25) keV for the half-life and {alpha} particle energy of {sup 207}Ac are also reported. {copyright} {ital 1998} {ital The American Physical Society}

  6. Nuclear clusters studied with alpha resonant scatterings using RI beams at CRIB

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Kahl, D.; Nakao, T.; Wakabayashi, Y.; Hashimoto, T.; Hayakawa, S.; Kawabata, T.; Teranishi, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. N.; Kubono, S.; Suhara, T.; Kanada-En'yo, Y.; Moon, J. Y.; Kim, A.; Iwasa, N.; Lee, P. S.; Chae, K. Y.; Cha, S. M.; Gwak, M. S.; Kim, D. H.; Milman, E.

    2014-12-01

    Alpha resonant scattering is a simple and promising method to study α-cluster structure in nuclei. It has several good features which enable us to perform measurements with short-lived and relatively low-intense RI beams. Several measurements on alpha resonant scattering have been carried out at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. Recent α resonant scattering studies at CRIB, using 7Li, 7Be and 10Be beams with a helium gas target, are discussed.

  7. Detection of Neutrons and Charged-Particles emitted in Peripheral and Mid-Peripheral Collisions of ^124,136Xe and ^112,124Sn Nuclei at E/A = 50 MeV

    NASA Astrophysics Data System (ADS)

    McIntosh, A. B.; Black, J.; Hudan, S.; Metelko, C. J.; Yanez, R.; de Souza, R. T.; Chbihi, A.; Famiano, M.; Fregeau, M. O.; Gauthier, J.; Moisan, J.; Roy, R.; Bianchin, S.; Schwarz, C.; Trautmann, W.

    2008-04-01

    To investigate peripheral and mid-peripheral heavy ion collisions, neutrons and charged particles emitted in the cross-bombardment reactions ^124,136Xe + ^112,124Sn @ E/A = 50 MeV were measured. Projectile-like fragments at small angles (2.8^o<=θ<=14.5^o) were identified by their atomic number and large velocity (V/Vbeam>=0.5) in the Si-Si-CsI(Tl)/PD array FIRST with high angular resolution (δθ 0.1^o). Intermediate mass fragments (IMF: Z>=3) detected in FIRST were isotopically identified. At larger angles (30^o<=θ<=45^o), light-charged particles and IMFs were isotopically identified in the silicon-strip array LASSA. With the DEMON array, pulse-shape discrimination and TOF were used to identify neutrons and measure their kinetic energies. Calibration of the charged particle detectors using fragmentation beams and electronic pulsers will be described. Elemental and isotopic resolution obtained with FIRST and LASSA will be shown; preliminary results will be presented.

  8. Isotope shifts of the 6d{sup 2} D{sub 3/2}-7 p{sup 2} P{sub 1/2} transition in trapped short-lived {sup 209-214}Ra{sup +}

    SciTech Connect

    Giri, G. S.; Versolato, O. O.; Berg, J. E. van den; Boell, O.; Dammalapati, U.; Hoek, D. J. van der; Jungmann, K.; Kruithof, W. L.; Mueller, S.; Nunez Portela, M.; Onderwater, C. J. G.; Santra, B.; Timmermans, R. G. E.; Wansbeek, L. W.; Willmann, L.; Wilschut, H. W.

    2011-08-15

    Laser spectroscopy of short-lived radium isotopes in a linear Paul trap has been performed. The isotope shifts of the 6d{sup 2} D{sub 3/2} -7 p{sup 2} P{sub 1/2} transition in {sup 209-214}Ra{sup +}, which are sensitive to the short-range part of the atomic wave functions, were measured. The results are essential experimental input for improving the precision of atomic structure calculations. This is indispensable for parity violation in Ra{sup +} aiming at the determination of the weak mixing angle.

  9. Efficiency and rate capability studies of the time-of-flight detector for isochronous mass measurements of stored short-lived nuclei with the FRS-ESR facility

    NASA Astrophysics Data System (ADS)

    Kuzminchuk-Feuerstein, Natalia; Fabian, Benjamin; Diwisch, Marcel; Plaß, Wolfgang R.; Geissel, Hans; Ayet San Andrés, Samuel; Dickel, Timo; Knöbel, Ronja; Scheidenberger, Christoph; Sun, Baohua; Weick, Helmut

    2016-06-01

    A time-of-flight (TOF) detector is used for Isochronous Mass Spectrometry (IMS) with the projectile fragment separator FRS and the heavy-ion storage ring ESR. Exotic nuclei are spatially separated in flight with the FRS at about 70% of the speed of light and are injected into the ESR. The revolution times of the stored ions circulating in the ESR are measured with a thin transmission foil detector. When the ions penetrate the thin detector foil, secondary electrons (SEs) are emitted from the surface and provide the timing information in combination with microchannel plate (MCP) detectors. The isochronous transport of the SEs is performed by perpendicular superimposed electric and magnetic fields. The detection efficiency and the rate capability of the TOF detector have been studied in simulations and experiments. As a result the performance of the TOF detector has been improved substantially: (i) The SE collection efficiency was doubled by use of an optimized set of electric and magnetic field values; now SEs from almost the full area of the foil are transmitted to the MCP detectors. (ii) The rate capability of the TOF detector was improved by a factor of four by the use of MCPs with 5 μm pore size. (iii) With these MCPs and a carbon foil with a reduced thickness of 10 μg/cm2 the number of recorded revolutions in the ESR has been increased by nearly a factor of 10. The number of recorded revolutions determine the precision of the IMS experiments. Heavy-ion measurements were performed with neon ions at 322 MeV/u and uranium fission fragments at about 370 MeV/u. In addition, measurements with an alpha source were performed in the laboratory with a duplicate of the TOF detector.

  10. On the analytic estimation of radioactive contamination from degraded alphas

    NASA Astrophysics Data System (ADS)

    Kadel, R. W.

    2016-03-01

    The high energy spectrum of alpha particles emitted from a single isotope uniformly contaminating a bulk solid has a flat energy spectrum with a high end cutoff energy equal to the maximal alpha kinetic energy (Tα) of the decay. In this flat region of the spectrum, we show the surface rate rb (Bq keV-1cm-2) arising from a bulk alpha contamination ρb (Bq cm-3) from a single isotope is given by rb =ρb Δ R/ 4 Δ E , where Δ E = E1-E2>0 is the energy interval considered (keV) in the flat region of the spectrum and Δ R = R2-R1, where R2 (R1) is the amount of the bulk material (cm) necessary to degrade the energy of the alpha from Tα to E2 (E1). We compare our calculation to a rate measurement of alphas from 147Sm, (15.32 ± 0.03% of Sm(nat) and half life of (1.06 ± 0.01)× 1011 yr [1]), and find good agreement, with the ratio between prediction to measurement of 100.2%± 1.6% (stat)± 2.1% (sys). We derive the condition for the flat spectrum, and also calculate the relationship between the decay rate measured at the surface for a [near] surface contamination with an exponential dependence on depth and a second case of an alpha source with a thin overcoat. While there is excellent agreement between our implementation of the sophisticated Monte Carlo program SRIM [2] and our intuitive model in all cases, both fail to describe the measured energy distribution of a 148Gd alpha source with a thin (~200μg cm-2) Au overcoat. We discuss possible origins of the disagreement and suggest avenues for future study.

  11. Advanced alpha spectrum analysis based on the fitting and covariance analysis of dependent variables

    NASA Astrophysics Data System (ADS)

    Ihantola, S.; Pelikan, A.; Pöllänen, R.; Toivonen, H.

    2011-11-01

    The correct handling of statistical uncertainties is crucial especially when unfolding alpha spectra that contain a low number of counts or overlapping peaks from different nuclides. For this purpose, we have developed a new spectrum analysis software package called ADAM, which performs a full covariance calculus for alpha-particle emitting radionuclides. By analyzing a large number of simulated and measured spectra, the program was proved to give unbiased peak areas and statistically correct uncertainty limits. This applies regardless of the peak areas and the number of unknown parameters during the fitting. In addition, ADAM performs reliable deconvolution for multiplets, which opens the way for the determination of isotope ratios, such as 239Pu/240Pu.

  12. In vitro cell irradiation systems based on 210Po alpha source: construction and characterisation

    NASA Technical Reports Server (NTRS)

    Szabo, J.; Feher, I.; Palfalvi, J.; Balashazy, I.; Dam, A. M.; Polonyi, I.; Bogdandi, E. N.

    2002-01-01

    One way of studying the risk to human health of low-level radiation exposure is to make biological experiments on living cell cultures. Two 210Po alpha-particle emitting devices, with 0.5 and 100 MBq activity, were designed and constructed to perform such experiments irradiating monolayers of cells. Estimates of dose rate at the cell surface were obtained from measurements by a PIPS alpha-particle spectrometer and from calculations by the SRIM 2000, Monte Carlo charged particle transport code. Particle fluence area distributions were measured by solid state nuclear track detectors. The design and dosimetric characterisation of the devices are discussed. c2002 Elsevier Science Ltd. All rights reserved.

  13. Fe-Ni and Al-Mg isotope records in UOC chondrules: Plausible stellar source of 60Fe and other short-lived nuclides in the early Solar System

    NASA Astrophysics Data System (ADS)

    Mishra, R. K.; Goswami, J. N.

    2014-05-01

    The short-lived now-extinct nuclide 60Fe, present in the early Solar System, is a unique product of stellar nucleosynthesis. Even though the first hint for its presence in the early Solar System was obtained more than two decades back, a robust value for Solar System initial (SSI) 60Fe/56Fe is yet to be established. A combined study of 26Al-26Mg and 60Fe-60Ni isotope systematics in chondrules from unequilibrated ordinary chondrites of low petrologic type, Semarkona (LL3.0), LEW 86134 (L3.0), and Y 791324 (L3.1), has been conducted to infer the value of SSI 60Fe/56Fe. Seven of the analysed chondrules host resolved radiogenic excess in both 60Ni and 26Mg resulting from in situ decay of the short-lived nuclides 60Fe and 26Al, respectively. The initial 26Al/27Al values for these chondrules range from (6.9 ± 5.8) × 10-6 to (3.01 ± 1.78) × 10-5 that suggest their formation between 2.1 and 0.6 Ma after CAIs. The initial 60Fe/56Fe at the time of formation of these chondrules ranges from (3.2 ± 1.3) × 10-7 to (1.12 ± 0.39) × 10-6 and show a good correlation with their initial 26Al/27Al values suggesting co-injection of the two short-lived nuclides, 60Fe and 26Al, into the protosolar cloud from the same stellar source. Considering 26Al as a reliable early Solar System chronometer, this data set yield a SSI 60Fe/56Fe value of (7.0 ± 1.2) × 10-7, if we adopt a half-life value of 2.6 Ma for 60Fe reported in a recent study. Model stellar nucleosynthesis yields suggest that both a high mass (5-6.5 M⊙) Asymptotic Giant Branch (AGB) star or a supernova (SN) could be the source of 60Fe and 26Al present in the early Solar System. A high mass (˜25 M⊙) SN appears more plausible because of the much higher probability of its close association with the protosolar molecular cloud than a high mass AGB star. Such a SN can also account for SSI abundance of 26Al and its correlated presence with 60Fe in chondrules.

  14. Direct mass measurements of short-lived A=2Z-1 nuclides (63)Ge, (65)As, (67)Se, and (71)Kr and their impact on nucleosynthesis in the rp process.

    PubMed

    Tu, X L; Xu, H S; Wang, M; Zhang, Y H; Litvinov, Yu A; Sun, Y; Schatz, H; Zhou, X H; Yuan, Y J; Xia, J W; Audi, G; Blaum, K; Du, C M; Geng, P; Hu, Z G; Huang, W X; Jin, S L; Liu, L X; Liu, Y; Ma, X; Mao, R S; Mei, B; Shuai, P; Sun, Z Y; Suzuki, H; Tang, S W; Wang, J S; Wang, S T; Xiao, G Q; Xu, X; Yamaguchi, T; Yamaguchi, Y; Yan, X L; Yang, J C; Ye, R P; Zang, Y D; Zhao, H W; Zhao, T C; Zhang, X Y; Zhan, W L

    2011-03-18

    Mass excesses of short-lived A=2Z-1 nuclei (63)Ge, (65)As, (67)Se, and (71)Kr have been directly measured to be -46,921(37), -46,937(85), -46,580(67), and -46,320(141)  keV, respectively. The deduced proton separation energy of -90(85)  keV for (65)As shows that this nucleus is only slightly proton unbound. X-ray burst model calculations with the new mass excess of (65)As suggest that the majority of the reaction flow passes through (64)Ge via proton capture, indicating that (64)Ge is not a significant rp-process waiting point. PMID:21469858

  15. K alpha line emission during solar X-ray bursts

    NASA Technical Reports Server (NTRS)

    Phillips, K. J. H.; Neupert, W. M.

    1973-01-01

    The expected flux of K alpha line emission from sulfur, argon, calcium, and iron is calculated during both thermal and nonthermal solar X-ray events. Such emission is shown to be weak during the course of most of the nonthermal hard X-ray bursts that Kane and Anderson (1970) have observed. If Compton backscattering is significant at high energies, the flux is reduced still further for disk flares, but it is noted that the strong, near-limb burst of June 26 would have produced about 100 photons /sq cm/sec of sulfur and iron K alpha emission. The impulsive hard X-ray bursts may in general be too short-lived for much K alpha emission. It may be noted that sulfur K alpha emission in particular depends sensitively on the lower-energy limit of the nonthermal electron spectrum, assuming such a sharply defined boundary exists. During soft X-ray bursts, when temperatures of a few 10 to the 7th power K are obtained, K alpha emission from certain iron ions, specifically Fe XVIII-XXIII, may be important.

  16. Alpha-1 Antitrypsin Test

    MedlinePlus

    ... helpful? Also known as: Alpha 1 -antitrypsin; A1AT; AAT Formal name: Alpha 1 Antitrypsin; α1-antitrypsin Related ... know? How is it used? Alpha-1 antitrypsin (AAT) testing is used to help diagnose alpha-1 ...

  17. Counting particles emitted by stratospheric aircraft and measuring size of particles emitted by stratospheric aircraft

    NASA Technical Reports Server (NTRS)

    Wilson, James Charles

    1994-01-01

    The ER-2 condensation nuclei counter (CNC) has been modified to reduce the diffusive losses of particles within the instrument. These changes have been successful in improving the counting efficiency of small particles at low pressures. Two techniques for measuring the size distributions of particles with diameters less than 0.17 micrometers have been evaluated. Both of these methods, the differential mobility analyzer (DMA) and the diffusion battery, have fundamental problems that limit their usefulness for stratospheric applications. We cannot recommend either for this application. Newly developed, alternative methods for measuring small particles include inertial separation with a low-loss critical orifice and thin-plate impactor device. This technique is now used to collect particles in the multisample aerosol collector housed in the ER-2 CNC-2, and shows some promise for particle size measurements when coupled with a CNC as a counting device. The modified focused-cavity aerosol spectrometer (FCAS) can determine the size distribution of particles with ambient diameters as small as about 0.07 micrometers. Data from this instrument indicates the presence of a nuclei mode when CNC-2 indicates high concentrations of particles, but cannot resolve important parameters of the distribution.

  18. Rapid alpha spectrometry from liquids doped with ²⁰⁹Po and ²⁴¹Am using simplified sample processing.

    PubMed

    Pöllänen, R; Simola, R; Vesterbacka, P

    2016-01-01

    Rapid detection of alpha-particle emitting radionuclides from liquids doped with (209)Po and (241)Am was investigated. These nuclides may mimic or be among those that could be used as threat agents in malevolent actions such as deliberate poisoning of refreshments. The liquids investigated here by using a semiconductor alpha detector in vacuum were coffee, beer and apple juice. Methods for the sample processing were rapid evaporation of the liquids and filtration. Both methods produced samples, which gave alpha spectra that could be readily analyzed by an unfolding program. The doped radionuclides were easily identified from the spectra, but the samples were too thick for reliable activity determination. Determination of the activity ratios is possible if the peak shapes are equal. However, radionuclides may behave differently during the sample preparation, which must be accounted for in the activity ratio determination. PMID:26516992

  19. DIFFERENCES AND SIMILARITIES IN ANDRA'S ASSESSMENT OF ACTIVITIES CARRIED OUT BY RADIOACTIVE WASTE GENERATORS AND AFFECTING THE QUALITY OF IL-LL SHORT-LIVED WASTE PACKAGES AND HL-IL LONG-LIVED WASTE PACKAGES

    SciTech Connect

    Trentesaux, C.; Cairon, P.; Dumont, J.-N.; Felix, B.; Losada, F.

    2003-02-27

    In both cases of packages for either low-level and intermediate-level short-lived (LL-IL/SL) or high-level and intermediate-level long-lived (HL-IL/LL) radioactive waste, Andra has defined a quality reference system, manages it, follows up its appropriate implementation in production plants and verifies its effectiveness in production. The purpose of such a reference system is to ensure, in the first case, that waste packages comply with the Centre de l'Aube's acceptance criteria and, in the second case, that the characteristics submitted by the waste generators to Andra as input data for the deep geological repository project reflect the actual production conditions. In that context, the three management steps of the quality reference system include differences due to the fact that HL-IL/SL packages have not been submitted yet to any technical acceptance criterion. Compliance with any such criterion should be the subject of a characterization report during the qualification phase and of a examination during the verification phase. The management of the quality reference system also involves similarities that facilitate the joint work carried out by Andra with the waste generators, especially in the facilities where both package types are produced.

  20. Phase I Rinal Report: Ultra-Low Background Alpha Activity Counter

    SciTech Connect

    Warburton, W.K.

    2005-07-22

    In certain important physics experiments that search for rare-events, such as neutrino or double beta decay detections, it is critical to minimize the number of background events that arise from alpha particle emitted by the natural radioactivity in the materials used to construct the experiment. Similarly, the natural radioactivity in materials used to connect and package silicon microcircuits must also be minimized in order to eliminate ''soft errors'' caused by alpha particles depositing charges within the microcircuits and thereby changing their logic states. For these, and related reasons in the areas of environmental cleanup and nuclear materials tracking, there is a need that is important from commercial, scientific, and national security perspectives to develop an ultra-low background alpha counter that would be capable of measuring materials' alpha particle emissivity at rates well below 0.00001 alpha/cm{sup 2}/hour. This rate, which corresponds to 24 alpha particles per square meter per day, is essentially impossible to achieve with existing commercial instruments because the natural radioactivity of the materials used to construct even the best of these counters produces background rates at the 0.005 alpha/cm{sup 2}/hr level. Our company (XIA) had previously developed an instrument that uses electronic background suppression to operate at the 0.0005 0.005 alpha/cm{sup 2}/hr level. This patented technology sets up an electric field between a large planar sample and a large planar anode, and fills the gap with pure Nitrogen. An alpha particle entering the chamber ionizes the Nitrogen, producing a ''track'' of electrons, which drift to the anode in the electric field. Tracks close to the anode take less than 10 microseconds (us) to be collected, giving a preamplifier signal with a 10 us risetime. Tracks from the sample have to drift across the full anode-sample gap and produce a 35 us risetime signal. By analyzing the preamplifier signals with a digital signal processor we easily distinguish between these two risetimes and thereby count only alpha particles emitted by the sample. Alpha particles emitted from the sample tray are absorbed in the rear of the sample, so the tray's emissivity does not contribute to the background either. Extensions of the method to the counter's sidewalls similarly allow us to reject alpha particles emitted from the sidewalls. We can thus able obtain background rates over a factor of 1000 lower than in conventional instruments without active background rejection. Extending this principle to count at the 0.00001 alpha/cm{sup 2}/hour, level encounters difficulties because there will typically be only 2.4 alpha particles per square meter per day. Since about 6 counts are required to measure activity at the 95% confidence level, large sample areas are required to make measurements in reasonable times. Unfortunately, increasing the counter's anode area to a square meter raises its capacitance so much that the preamplifier noise levels swamp the alpha particle signals and make counting impossible. In this SBIR we worked to solve this dilemma by segmenting the single large area electrode into several smaller, lower capacitance electrodes that could still detect the alpha particles reliably. Each electrode would have its own electronic and we would capture signals from all of them in coincidence (since an alpha track might well deposit charge on more than one electrode), a technique in which XIA is experienced. Therefore, in Phase I we worked to show proof of principle by subdividing our original 1,800 cm{sup 2} electrode into 4 square segments, each 625 cm{sup 2} and demonstrating that signal noise on individual channels reduced as expected. Because the Phase II counter with a 1 m{sup 2} segmented anode would require 16 segments plus a segmented guard as well, we also designed low cost signal processing electronics to instrument it in Phase II. Our Phase I effort met our major proof of principle goals. In particular, reducing the anode size by a factor of 4 in area reduced electronic noise by 3. We also developed an analytical model of signal generation as the charges in the track drift across the counter and showed that the features observed in the real signals closely resembled those predicted by the model. When we captured events where the track charge was indeed collected by two electrodes, we showed that, by summing them, we could recover the preamplifier signal shape appropriate to collection by a single electrode. We thereby showed that we could achieve noise levels that would allow us to analyze our signals with even higher precision than in our current instrument while being able to increase the measured sample area to the values needed to attain the proposed 0.00001 alpha/cm{sup 2}/hour sensitivity.

  1. Traversal of cells by radiation and absorbed fraction estimates for electrons and alpha particles

    SciTech Connect

    Eckerman, K.F.; Ryman, J.C.; Taner, A.C.; Kerr, G.D.

    1985-01-01

    Consideration of the pathlength which radiation traverses in a cell is central to algorithms for estimating energy deposition on a cellular level. Distinct pathlength distributions occur for radionuclides: (1) uniformly distributed in space about the cell (referred to as -randomness); (2) uniformly distributed on the surface of the cell (S-randomness); and (3) uniformly distributed within the cell volume (I-randomness). For a spherical cell of diameter d, the mean pathlengths are 2/3d, 1/2d, and 3/4d, respectively, for these distributions. Algorithms for simulating the path of radiation through a cell are presented and the absorbed fraction in the cell and its nucleus are tabulated for low energy electrons and alpha particles emitted on the surface of spherical cells. The algorithms and absorbed fraction data should be of interest to those concerned with the dosimetry of radionuclide-labeled monoclonal antibodies. 8 refs., 3 figs., 2 tabs.

  2. Sterically stabilized liposomes as a carrier for alpha-emitting radium and actinium radionuclides.

    PubMed

    Henriksen, Gjermund; Schoultz, B W; Michaelsen, T E; Bruland, Ø S; Larsen, R H

    2004-05-01

    The alpha-particle emitting radionuclides (223)Ra (t(1/2) = 11.4 d), (224)Ra (t(1/2) = 3.6 d), and (225)Ac(t(1/2) = 10.0 d) may have a broad application in targeted radiotherapy provided that they could be linked to vehicles with tumor affinity. The potential usefulness of liposomes as carriers was studied in the present work. Radium and actinium radionuclides could be loaded in good yields into sterically stabilized liposomes. Subsequent coating of the liposomes with a folate-F(ab')(2) construct yielded a product with affinity towards tumor cells expressing folate receptors. Radionuclide loaded liposomes showed excellent stability in serum in vitro. PMID:15093814

  3. RAPID DETERMINATION OF ACTINIDES IN URINE BY INDUCTIVELY-COUPLED PLASMA MASS SPECTROMETRY AND ALPHA SPECTROMETRY: A HYBRID APPROACH

    SciTech Connect

    Maxwell, S.; Jones, V.

    2009-05-27

    A new rapid separation method that allows separation and preconcentration of actinides in urine samples was developed for the measurement of longer lived actinides by inductively coupled plasma mass spectrometry (ICP-MS) and short-lived actinides by alpha spectrometry; a hybrid approach. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration, if required, is performed using a streamlined calcium phosphate precipitation. Similar technology has been applied to separate actinides prior to measurement by alpha spectrometry, but this new method has been developed with elution reagents now compatible with ICP-MS as well. Purified solutions are split between ICP-MS and alpha spectrometry so that long- and short-lived actinide isotopes can be measured successfully. The method allows for simultaneous extraction of 24 samples (including QC samples) in less than 3 h. Simultaneous sample preparation can offer significant time savings over sequential sample preparation. For example, sequential sample preparation of 24 samples taking just 15 min each requires 6 h to complete. The simplicity and speed of this new method makes it attractive for radiological emergency response. If preconcentration is applied, the method is applicable to larger sample aliquots for occupational exposures as well. The chemical recoveries are typically greater than 90%, in contrast to other reported methods using flow injection separation techniques for urine samples where plutonium yields were 70-80%. This method allows measurement of both long-lived and short-lived actinide isotopes. 239Pu, 242Pu, 237Np, 243Am, 234U, 235U and 238U were measured by ICP-MS, while 236Pu, 238Pu, 239Pu, 241Am, 243Am and 244Cm were measured by alpha spectrometry. The method can also be adapted so that the separation of uranium isotopes for assay is not required, if uranium assay by direct dilution of the urine sample is preferred instead. Multiple vacuum box locations may be set-up to supply several ICP-MS units with purified sample fractions such that a high sample throughput may be achieved, while still allowing for rapid measurement of short-lived actinides by alpha spectrometry.

  4. Rapid determination of actinides in urine by inductively coupled plasma mass spectrometry and alpha spectrometry: a hybrid approach.

    PubMed

    Maxwell, Sherrod L; Jones, Vernon D

    2009-11-15

    A new rapid separation method that allows separation and preconcentration of actinides in urine samples was developed for the measurement of longer lived actinides by inductively coupled plasma mass spectrometry (ICP-MS) and short-lived actinides by alpha spectrometry; a hybrid approach. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration, if required, is performed using a streamlined calcium phosphate precipitation. Similar technology has been applied to separate actinides prior to measurement by alpha spectrometry, but this new method has been developed with elution reagents now compatible with ICP-MS as well. Purified solutions are split between ICP-MS and alpha spectrometry so that long- and short-lived actinide isotopes can be measured successfully. The method allows for simultaneous extraction of 24 samples (including QC samples) in less than 3h. Simultaneous sample preparation can offer significant time savings over sequential sample preparation. For example, sequential sample preparation of 24 samples taking just 15 min each requires 6h to complete. The simplicity and speed of this new method makes it attractive for radiological emergency response. If preconcentration is applied, the method is applicable to larger sample aliquots for occupational exposures as well. The chemical recoveries are typically greater than 90%, in contrast to other reported methods using flow injection separation techniques for urine samples where plutonium yields were 70-80%. This method allows measurement of both long-lived and short-lived actinide isotopes. (239)Pu, (242)Pu, (237)Np, (243)Am, (234)U, (235)U and (238)U were measured by ICP-MS, while (236)Pu, (238)Pu, (239)Pu, (241)Am, (243)Am and (244)Cm were measured by alpha spectrometry. The method can also be adapted so that the separation of uranium isotopes for assay is not required, if uranium assay by direct dilution of the urine sample is preferred instead. Multiple vacuum box locations may be set-up to supply several ICP-MS units with purified sample fractions such that a high sample throughput may be achieved, while still allowing for rapid measurement of short-lived actinides by alpha spectrometry. PMID:19782204

  5. EVOLUTION OF THE SOLAR NEBULA. IX. GRADIENTS IN THE SPATIAL HETEROGENEITY OF THE SHORT-LIVED RADIOISOTOPES {sup 60}Fe AND {sup 26}Al AND THE STABLE OXYGEN ISOTOPES

    SciTech Connect

    Boss, Alan P.

    2011-10-01

    Short-lived radioisotopes (SLRIs) such as {sup 60}Fe and {sup 26}Al were likely injected into the solar nebula in a spatially and temporally heterogeneous manner. Marginally gravitationally unstable (MGU) disks, of the type required to form gas giant planets, are capable of rapid homogenization of isotopic heterogeneity as well as of rapid radial transport of dust grains and gases throughout a protoplanetary disk. Two different types of new models of an MGU disk in orbit around a solar-mass protostar are presented. The first set has variations in the number of terms in the spherical harmonic solution for the gravitational potential, effectively studying the effect of varying the spatial resolution of the gravitational torques responsible for MGU disk evolution. The second set explores the effects of varying the initial minimum value of the Toomre Q stability parameter, from values of 1.4 to 2.5, i.e., toward increasingly less unstable disks. The new models show that the basic results are largely independent of both sets of variations. MGU disk models robustly result in rapid mixing of initially highly heterogeneous distributions of SLRIs to levels of {approx}10% in both the inner (<5 AU) and outer (>10 AU) disk regions, and to even lower levels ({approx}2%) in intermediate regions, where gravitational torques are most effective at mixing. These gradients should have cosmochemical implications for the distribution of SLRIs and stable oxygen isotopes contained in planetesimals (e.g., comets) formed in the giant planet region ({approx}5 to {approx}10 AU) compared to those formed elsewhere.

  6. Effects of Geologically Short-Lived Surface Water Perturbations on the Calcareous Nannoplankton as Exemplified by the Paleocene-Eocene Thermal Maximum and Cretaceous Oceanic Anoxic Event OAE1d

    NASA Astrophysics Data System (ADS)

    Bralower, T. J.; Watkins, D. K.

    2007-12-01

    Calcareous nannoplankton are obligate photoautotrophs restricted to the photic zone in the open ocean. Disruptions to the chemical and physical structure of the surface water mass constitute the most important environmental stresses forcing evolutionary changes. Surface-water environmental perturbations in ancient oceans provide opportunities to test the effects of these stresses on ancient plankton communities. Here we present data from the Paleocene-Eocene Thermal Maximum (PETM) at 55 Ma and mid-Cretaceous (late Albian) oceanic anoxic event (OAE) 1d at 98 Ma, and compare changes in nannoplankton communities, including extinctions and originations (taxonomic turnover) and temporary assemblage shifts, with the extent and rate of change in environmental variables including temperature, thermal stratification, carbon export and alkalinity. In the case of the PETM, high rates of taxonomic turnover affected both oligotrophic and mesotrophic species. These taxa were relatively minor parts of the total assemblages, however, and the numerically abundant species were not affected permanently. The event is associated with a wholesale assemblage shift, including common and rare taxa, that varies from one oceanic setting to another. Highest rates of turnover and assemblage shift occurred during intervals when the rate of change of environmental variables including temperature, stratification and carbon export is highest. Relatively minor perturbations in the structure of the upper surface water mass, such as that associated with OAE1d, led to selective extinction of morphologically specialized oligotrophic taxa that were dependent upon maintaining a fixed position in a stable, stratified water column. These taxa were relatively rare components of the late Albian assemblages. In addition, the environmental changes associated with the anoxic event were coincident with originations and extinctions of less specialized clades undergoing adaptive radiation. These examples suggest that geologically brief perturbations of the upper water column affect only rare taxa permanently, while the more common calcareous nannoplankton exhibit a remarkable resilience to the effects of all but the most extreme short-lived disruptions of the surface water mass.

  7. The effect of copper on the precipitation of scorodite (FeAsO4·2H2O) under hydrothermal conditions: evidence for a hydrated copper containing ferric arsenate sulfate-short lived intermediate.

    PubMed

    Gomez, M A; Becze, L; Celikin, M; Demopoulos, G P

    2011-08-15

    The effect of copper sulfate on scorodite precipitation and its mechanism of formation at 150 °C was investigated. Scorodite was determined to be the dominant phase formed under all conditions explored (0.61 < Fe(III)/As(V) < 1.87, 0.27-0.30 M Fe(SO(4))(1.5), 0-0.3 M CuSO(4), 0-0.3 M MgSO(4), at 2.5 h and 150 °C). The produced scorodite was found to incorporate up to 5% SO(4) and ≤1% Cu or Mg in its structure. The precipitation of scorodite was stoichiometric, i.e. the Fe/As molar ratio in the solids was equal to one independent of the starting Fe/As ratio in the solution. The presence of excess ferric sulfate in the initial solution (Fe/As>1) was found to slow down the ordering of the H-bond structure in scorodite. Precipitation under equimolar concentrations (As = Fe = Cu = 0.3 M), short times and lower temperatures (30-70 min and 90-130 °C) revealed the formation of a Cu-Fe-AsO(4)-SO(4)-H(2)O short lived gelatinous intermediate that closely resembled the basic ferric arsenate sulfate (BFAS) type of phase, before ultimately converting fully to the most stable scorodite phase (96 min and 138 °C). This phase transition has been traced throughout the reaction via elemental (ICP-AES, XPS), structural (PXRD, TEM) and molecular (ATR-IR, Raman) analysis. ATR-IR investigation of an arsenic containing industrial residue produced during pressure leaching of a copper concentrate (1 h and 150 °C) found evidence of the formation of an arsenate mineral form resembling the intermediate basic ferric arsenate sulfate phase. PMID:21621789

  8. Effects of alpha-particles on survival and chromosomal aberrations in human mammary epithelial cells

    NASA Technical Reports Server (NTRS)

    Durante, M.; Grossi, G. F.; Gialanella, G.; Pugliese, M.; Nappo, M.; Yang, T. C.

    1995-01-01

    We have studied the radiation responses of a human mammary epithelial cell line, H184B5 F5-1 M/10. This cell line was derived from primary mammary cells after treatment with chemicals and heavy ions. The F5-1 M/10 cells are immortal, density-inhibited in growth, and non-tumorigenic in athymic nude mice and represent an in vitro model of the human epithelium for radiation studies. Because epithelial cells are the target of alpha-particles emitted from radon daughters, we concentrated our studies on the efficiency of alpha-particles. Confluent cultures of M/10 cells were exposed to accelerated alpha-particles [beam energy incident at the cell monolayer = 3.85 MeV, incident linear energy transfer (LET) in cell = 109 keV/microns] and, for comparison, to 80 kVp x-rays. The following endpoints were studied: (1) survival, (2) chromosome aberrations at the first postirradiation mitosis, and (3) chromosome alterations at later passages following irradiation. The survival curve was exponential for alpha-particles (D0 = 0.73 +/- 0.04 Gy), while a shoulder was observed for x-rays (alpha/beta = 2.9 Gy; D0 = 2.5 Gy, extrapolation number 1.6). The relative biological effectiveness (RBE) of high-LET alpha-particles for human epithelial cell killing was 3.3 at 37% survival. Dose-response curves for the induction of chromosome aberrations were linear for alpha-particles and linearquadratic for x-rays. The RBE for the induction of chromosome aberrations varied with the type of aberration scored and was high (about 5) for chromosome breaks and low (about 2) for chromosome exchanges.(ABSTRACT TRUNCATED AT 250 WORDS).

  9. Determination of alpha dose rate profile at the HLW nuclear glass/water interface

    NASA Astrophysics Data System (ADS)

    Mougnaud, S.; Tribet, M.; Rolland, S.; Renault, J.-P.; Jégou, C.

    2015-07-01

    Alpha irradiation and radiolysis can affect the alteration behavior of High Level Waste (HLW) nuclear glasses. In this study, the way the energy of alpha particles, emitted by a typical HLW glass, is deposited in water at the glass/water interface is investigated, with the aim of better characterizing the dose deposition at the glass/water interface during water-induced leaching mechanisms. A simplified chemical composition was considered for the nuclear glass under study, wherein the dose rate is about 140 Gy/h. The MCNPX calculation code was used to calculate alpha dose rate and alpha particle flux profiles at the glass/water interface in different systems: a single glass grain in water, a glass powder in water and a water-filled ideal crack in a glass package. Dose rate decreases within glass and in water as distance to the center of the grain increases. A general model has been proposed to fit a dose rate profile in water and in glass from values for dose rate in glass bulk, alpha range in water and linear energy transfer considerations. The glass powder simulation showed that there was systematic overlapping of radiation fields for neighboring glass grains, but the water dose rate always remained lower than the bulk value. Finally, for typical ideal cracks in a glass matrix, an overlapping of irradiation fields was observed while the crack aperture was lower than twice the alpha range in water. This led to significant values for the alpha dose rate within the crack volume, as long as the aperture remained lower than 60 μm.

  10. Local Control of Lung Derived Tumors by Diffusing Alpha-Emitting Atoms Released From Intratumoral Wires Loaded With Radium-224

    SciTech Connect

    Cooks, Tomer; Schmidt, Michael; Bittan, Hadas; Lazarov, Elinor; Arazi, Lior; Kelson, Itzhak; Keisari, Yona

    2009-07-01

    Purpose: Diffusing alpha-emitters radiation therapy (DART) is a new form of brachytherapy enabling the treatment of solid tumors with alpha radiation. The present study examines the antitumoral effects resulting from the release of alpha emitting radioisotopes into solid lung carcinoma (LL2, A427, and NCI-H520). Methods and Materials: An in vitro setup tested the dose-dependent killing of tumor cells exposed to alpha particles. In in vivo studies, radioactive wires (0.3 mm diameter, 5 mm long) with {sup 224}Ra activities in the range of 21-38 kBq were inserted into LL/2 tumors in C57BL/6 mice and into human-derived A427 or NCI-H520 tumors in athymic mice. The efficacy of the short-lived daughters of {sup 224}Ra to produce tumor growth retardation and prolong life was assessed, and the spread of radioisotopes inside tumors was measured using autoradiography. Results: The insertion of a single DART wire into the center of 6- to 7-mm tumors had a pronounced retardation effect on tumor growth, leading to a significant inhibition of 49% (LL2) and 93% (A427) in tumor development and prolongations of 48% (LL2) in life expectancy. In the human model, more than 80% of the treated tumors disappeared or shrunk. Autoradiographic analysis of the treated sectioned tissue revealed the intratumoral distribution of the radioisotopes, and histological analysis showed corresponding areas of necrosis. In vitro experiments demonstrated a dose-dependent killing of tumors cells exposed to alpha particles. Conclusions: Short-lived diffusing alpha-emitters produced tumor growth retardation and increased survival in mice bearing lung tumor implants. These results justify further investigations with improved dose distributions.

  11. Ab initio alpha-alpha scattering

    NASA Astrophysics Data System (ADS)

    Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A.; Luu, Thomas; Meißner, Ulf-G.

    2015-12-01

    Processes such as the scattering of alpha particles (4He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei—nuclei with even and equal numbers of protons and neutrons—is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the ‘adiabatic projection method’ to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of quarks and gluons.

  12. Ab initio alpha-alpha scattering.

    PubMed

    Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A; Luu, Thomas; Meißner, Ulf-G

    2015-12-01

    Processes such as the scattering of alpha particles ((4)He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei--nuclei with even and equal numbers of protons and neutrons--is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the 'adiabatic projection method' to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of quarks and gluons. PMID:26632590

  13. Measurement of (222)Rn by absorption in plastic scintillators and alpha/beta pulse shape discrimination.

    PubMed

    Mitev, Krasimir K

    2016-04-01

    This work demonstrates that common plastic scintillators like BC-400, EJ-200 and SCSF-81 absorb radon and their scintillation pulse decay times are different for alpha- and beta-particles. This allows the application of pulse shape analysis for separation of the pulses of alpha- and beta-particles emitted by the absorbed radon and its progeny. It is shown that after pulse shape discrimination of beta-particles' pulses, the energy resolution of BC-400 and EJ-200 alpha spectra is sufficient to separate the peaks of (222)Rn, (218)Po and (214)Po and allows (222)Rn measurements that are unaffected by the presence of thoron ((220)Rn) in the environment. The alpha energy resolution of SCSF-81 in the experiments degrades due to imperfect collection of the light emitted inside the scintillating fibers. The experiments with plastic scintillation microspheres (PSM) confirm previous findings of other researchers that PSM have alpha-/beta-discrimination properties and show suitability for radon measurements. The diffusion length of radon in BC-400 and EJ-200 is determined. The pilot experiments show that the plastic scintillators are suitable for radon-in-soil-gas measurements. Overall, the results of this work suggest that it is possible to develop a new type of radon measurement instruments which employ absorption in plastic scintillators, pulse-shape discrimination and analysis of the alpha spectra. Such instruments can be very compact and can perform continuous, real-time radon measurements and thoron detection. They can find applications in various fields from radiation protection to earth sciences. PMID:26851823

  14. alpha-Hexachlorocyclohexane (alpha-HCH)

    Integrated Risk Information System (IRIS)

    alpha - Hexachlorocyclohexane ( alpha - HCH ) ; CASRN 319 - 84 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Ass

  15. Azimuthal 2{alpha} correlations and projectile-residue distributions selected by neutron and charged-particle multiplicity measurements

    SciTech Connect

    Kunde, G.J.; Gaff, S.; Gelbke, C.K.; Glasmacher, T.; Huang, M.J.; Lemmon, R.; Lynch, W.G.; Manduci, L.; Martin, L.; Popescu, R.; Tsang, M.B.; Dempsey, J.; Charity, R.J.; Sobotka, L.G.; Agnihotri, D.K.; Djerroud, B.; Schroeder, W.U.; Skulski, W.; Toke, J.; Wyrozebski, K.; Ruess, D.

    1997-03-01

    The resolution of reaction filters for intermediate-energy heavy-ion collisions based upon charged-particle and neutron multiplicity measurements with 4{pi} coverage is compared for {sup 112}Sn+{sup 112}Sn and {sup 124}Sn+{sup 124}Sn collisions at E/A=40 MeV. The quality of event characterization is inferred from the azimuthal correlations of {alpha} particles emitted at intermediate rapidity and from the {ital Z} distributions of projectilelike fragments emitted at forward angles. For central and midimpact parameter collisions, the associated charged-particle multiplicity appears to provide better impact-parameter selection than the associated neutron multiplicity. {copyright} {ital 1997} {ital The American Physical Society}

  16. 18O/ 16O mapping and hydrogeology of a short-lived (?10 years) fumarolic (>500C) meteoric-hydrothermal event in the upper part of the 0.76 Ma Bishop Tuff outflow sheet, California

    NASA Astrophysics Data System (ADS)

    Holt, Elizabeth Warner; Taylor, Hugh P.

    1998-07-01

    18O/ 16O data from the 200-m-thick, 0.76 Ma Bishop Tuff outflow sheet provide evidence for a vigorous, short-lived (?10 years), high-temperature, fumarolic meteoric-hydrothermal event. This is proved by: (1) the juxtaposition in the upper, partially welded Bishop Tuff of low- 18O groundmass/glass ( ?18O=-5 to +3) with coexisting quartz and feldspar phenocrysts having magmatic ?18O values (+8.70.3; +7.50.3); and (2) the fact that these kinds of 18O/ 16O signatures correlate very well with morphological features and mapped zones of fumarolic activity. Profiles of ?18O with depth in the Bishop Tuff within the fumarole area define a 40- to 50-m-thick, low- 18O, stratigraphic zone that is sandwiched between the essentially unwelded near-surface portion of the tuff and an underlying, densely welded black tuff that displays magmatic 18O/ 16O values. Shallow-dipping columnar joints and other fumarolic features (i.e., subhorizontal tubular conduits and steep fissures) correlate very well with these pervasively devitrified, low- 18O zones. The base of the low- 18O zone is extremely sharp (3 per meter) and is located directly above the transition from partially welded tuff to densely welded black tuff. The observed average whole-rock 18O-depletions within this low- 18O zone are about 6-7, requiring meteoric water/rock ratios in excess of 0.24 in mass units. Rainfall on the surface of the tuff would not have been high enough to supply this much H 2O in the short lifetime of fumarolic activity, suggesting that some recharge must have been from groundwater flow through the upper part of the tuff, above the sloping (1-5) top of the impermeable lower zone. This is compatible with the observation that the fumarolic areas roughly correlate with the preeruptive regional drainage pattern. Some of this recharge may in part have been from the lake that filled Long Valley caldera, which was dammed by the Bishop Tuff up to the level of this boundary between the partially and densely welded zones (?7000 ft, the elevation of the highest Long Valley Lake shorelines). Gazis et al. had previously shown that the 2.8-Ma intracaldera Chegem Tuff from the Caucasus Mountains exhibits exactly the same kind of 18O-signature that we have correlated with fossil fumaroles in the Bishop Tuff outflow sheet. Although not recognized as such by McConnell et al.; 18O/ 16O data from drill-hole samples from the intracaldera Bishop Tuff in Long Valley also display this characteristic 18O signature (i.e., analogous ?18O-depth profiles, as well as low- 18O groundmass coexisting with high- 18O feldspar phenocrysts). This fumarolic 18O/ 16O signature is observed to much greater depths (?650-750 m) in the intracaldera tuffs (?1500 m thick) than it is in the ?200-m-thick Bishop Tuff outflow sheet (?80 m depth).

  17. Alpha One Foundation

    MedlinePlus

    ... Stories A lung-affected Alpha enjoys hiking up mountains when she is not on duty as a ... police officer. Read More Alpha police officer climbs mountains in her spare time Eight-year-old Lucas ...

  18. Accelerator Production of 225Ac For Alpha-Immunotherapy

    NASA Astrophysics Data System (ADS)

    Weidner, J. W.; Nortier, F. M.; Bach, H. T.; John, K. D.; Couture, A.; Ullmann, J. L.; Fassbender, M. E.; Goff, G. S.; Taylor, W.; Valdez, F.; Wolfsberg, L. E.; Cisneros, M.; Dry, D.; Gallegos, M.; Gritzo, R.; Bitteker, L. J.; Wender, S.; Baty, R. S.

    2011-06-01

    225Ac has tremendous potential for the treatment of metastatic cancer due to the four alpha-particles emitted during its decay to stable 209Bi. Additionally, it is one of the few alpha-emitters being considered for clinical trials. The anticipated 225Ac demand for these trials is expected to far exceed the annual worldwide supply of approximately 1,000 mCi/yr. Consequently, the DOE Office of Science has funded investigations into accelerator-based production of 225Ac. Existing 232Th(p,x)225Ac cross section data indicate that up to 480 mCi/day of 225Ac could be created by bombarding a thick target of natural thorium with 100 MeV protons at the Los Alamos Isotope Production Facility. To verify these predictions, experiments are underway at the Los Alamos Neutron Science Center to measure the 232Th(p,x)225Ac production cross sections for protons in the energy range 40-200 MeV, and at 800 MeV. For 800 MeV protons, preliminary results indicate that the 225Ac production cross section is 12.4±0.6 mb and the 225Ra production cross section is 3.2±0.2 mb. Moreover, preliminary results suggest that the 227Ac production cross section is 16±1 mb. Experiments to measure these same cross sections at proton energies below 200 MeV are planned for the last half of calendar year 2010.

  19. Accelerator Production of {sup 225}Ac For Alpha-Immunotherapy

    SciTech Connect

    Weidner, J. W.; Nortier, F. M.; Bach, H. T.; John, K. D.; Couture, A.; Ullmann, J. L.; Fassbender, M. E.; Goff, G. S.; Taylor, W.; Valdez, F.; Wolfsberg, L. E.; Cisneros, M.; Dry, D.; Gallegos, M.; Gritzo, R.; Bitteker, L. J.; Wender, S.; Baty, R. S.

    2011-06-01

    {sup 225}Ac has tremendous potential for the treatment of metastatic cancer due to the four alpha-particles emitted during its decay to stable {sup 209}Bi. Additionally, it is one of the few alpha-emitters being considered for clinical trials. The anticipated {sup 225}Ac demand for these trials is expected to far exceed the annual worldwide supply of approximately 1,000 mCi/yr. Consequently, the DOE Office of Science has funded investigations into accelerator-based production of {sup 225}Ac. Existing {sup 232}Th(p,x){sup 225}Ac cross section data indicate that up to 480 mCi/day of {sup 225}Ac could be created by bombarding a thick target of natural thorium with 100 MeV protons at the Los Alamos Isotope Production Facility. To verify these predictions, experiments are underway at the Los Alamos Neutron Science Center to measure the {sup 232}Th(p,x){sup 225}Ac production cross sections for protons in the energy range 40-200 MeV, and at 800 MeV. For 800 MeV protons, preliminary results indicate that the {sup 225}Ac production cross section is 12.4{+-}0.6 mb and the {sup 225}Ra production cross section is 3.2{+-}0.2 mb. Moreover, preliminary results suggest that the {sup 227}Ac production cross section is 16{+-}1 mb. Experiments to measure these same cross sections at proton energies below 200 MeV are planned for the last half of calendar year 2010.

  20. The Alpha Centauri System.

    ERIC Educational Resources Information Center

    Soderblom, David R.

    1987-01-01

    Describes the Alpha Centauri star system, which is the closest star system to the sun. Discusses the difficulties associated with measurements involving Alpha Centauri, along with some of the recent advances in stellar seismology. Raises questions about the possibilities of planets around Alpha Centauri. (TW)

  1. Experimental Identification of Spin-Parities and Single-Particle Configurations in {sup 257}No and Its {alpha}-Decay Daughter {sup 253}Fm

    SciTech Connect

    Asai, M.; Tsukada, K.; Ichikawa, S.; Nagame, Y.; Nishinaka, I.; Akiyama, K.; Sakama, M.; Ishii, T.; Osa, A.; Oura, Y.; Sueki, K.; Shibata, M.

    2005-09-02

    {alpha}-{gamma} and {alpha}-electron coincidence spectroscopy for a short-lived heavy actinide nucleus {sup 257}No (T{sub 1/2}=24.5 s) has been performed using a gas-jet transport system and an on-line isotope separator. Spin-parities of excited states in {sup 253}Fm fed by the {alpha} decay of {sup 257}No have been identified on the basis of the measured internal conversion coefficients. The {nu}3/2{sup +}[622] configuration has been assigned to the ground state of {sup 257}No as well as to the 124.1 keV level in {sup 253}Fm. It was found that the ground-state configuration of {sup 257}No is different from that of lighter N=155 isotones.

  2. Observation of lunar radon emanation with the Apollo 15 alpha particle spectrometer.

    NASA Technical Reports Server (NTRS)

    Gorenstein, P.; Bjorkholm, P.

    1972-01-01

    The alpha particle spectrometer, a component of the orbital Sim Bay group of 'geochemistry' experiments on Apollo 15, was designed to detect alpha particles emitted during the decay of isotopes of radon gas and her daughter products. The purpose was to measure the gross activity of radon on the lunar surface and to find possible regions of increased local activity. Results are presented from a partial analysis of Apollo 15 data. For the moon as a whole, Rn220 was not observed and the upper limit on its decay rate above the lunar surface is 0.00038 disintegrations/sq cm-sec. Rn222 was marginally observed. Possible variations of radon activity on the lunar surface are being investigated. Po210 (a daughter product of Rn222) has been detected in a broad region from west of Mare Crisium to the Van de Graaff-Orlov region. The observed count rate is (4.6 plus or minus 1.4) x 0.001 disintegrations/sq cm-sec. The observed level of Po210 activity is in excess of the amount that would be in equilibrium with Rn222 by about an order of magnitude. This implies that larger levels of radon emanation have occurred on the moon within a time scale of 10 to 100 years.

  3. Targeted alpha therapy: evidence for potential efficacy of alpha-immunoconjugates in the management of micrometastatic cancer.

    PubMed

    Allen, B J

    1999-11-01

    There can be little doubt that one of the most important problems in the management of cancer is control of metastatic disease. This objective must be achieved ideally with a systemic therapeutic modality that targets cancer cells and gives minimal collateral damage to critical normal cells. The efficacy of targeted cancer therapy relies on the ability of a toxin to be located in the target cancer cell. The ideal toxin is one that is active only in the cancer cell, and not in critical normal cells. Failing this, the next best approach is a toxin with a short effective lifetime to target early stage micrometastatic disease. This rules out chemical toxins, given that they remain effective until excreted from the body, and localization of dose to the cancer cell rules out beta-emitting radio-isotopes (RI). Alpha-emitting RI, however, are much more appropriate toxins because they are short-lived and because their cytotoxicity is the result of their high rate of energy loss and short range of the alpha particles. These radionuclides have properties that are particularly suited for the elimination of single cells in transit or small nests of cancer cells. In vitro and in vivo experiments with alpha RI show dramatic superiority over beta RI. Only a few nuclear hits are needed to kill cells, and the formation of metastatic lung lesions and subcutaneous lesions in mice can be inhibited by systemic administration of alpha emitters. But alpha RI have not been able to control solid tumours, for which beta RI are better suited. A small number of alpha-emitting radionuclides are currently under investigation. These are terbium (Tb)-149, astatine (At)-211, bismuth (Bi)-212 and Bi-213. Terbium-149 and At-211 both require accelerators in close proximity to the place of application. The Bi isotopes are produced by long-lived parents and, as such, can be obtained from generators. The first phase-1 dose escalation trial with Bi-213 radioimmunoconjugate (RIC) commenced in New York in 1997, and other trials are planned with At-211 RIC and At-211 methylene blue for melanoma. Actinium (Ac)-225 is obtained from the decay of thorium (Th)-229, which is a waste product in the enrichment of fissile Th-233. Alternative accelerator production routes are being investigated, beginning with the European Centre for Nuclear Research (CERN) GeV proton spallation source. The ready and low-cost availability of the Ac:Bi generator is an important element in the implementation of clinical trials for patients with poor prognoses but without evidence of metastatic disease. PMID:10901964

  4. Development of the dual scintillator sheet and Phoswich detector for simultaneous Alpha- and Beta-rays measurement

    SciTech Connect

    Seo, B.K.; Kim, G.H.; Park, C.H.; Jung, Y.H.; Jung, C.H.; Lee, K.W.; Han, M.J.

    2007-07-01

    Thin sheet type of ZnS(Ag)/plastic dual scintillator for simultaneous counting of alpha- and beta-particles using a organic and inorganic scintillator widely used in the radiation measurement was manufactured, which could be applicable in the contamination monitoring systems. Counting materials were manufactured by solidification of the scintillator solution which mixed scintillator, solvent, and polymer. Prepared dual scintillator is a counting material which can simultaneously measure the alpha- and beta-particles. It was divided into two parts : an inorganic scintillator layer for alpha-particle detection and an organic one for beta-particle detection. The organic layer was composed of 2,5-diphenyloxazole [PPO] and 1,4,-bis[5-phenyl(oxazolyl)benzene] [POPOP] acting as the scintillator and polysulfone acting as the polymer. The inorganic layer was composed of ZnS(Ag) as scintillator and polysulfone as paste. The ZnS(Ag) scintillator layer was printed onto the organic layer using screen printing method. To estimate the detection ability of the prepared counting materials, alpha-particle emitting nuclide, Am-241, and beta emitting nuclide, Sr/Y-90, were used. The scintillations produced by interaction between radiation and scintillator were measured by photomultiplier tube. The overall counting results reveal that the developed detector is efficient for simultaneous counting of alpha- and beta-particles. For application test, the dual scintillator was fabricated with a Phoswich detector for monitoring the in-pipe alpha and beta contamination. To deploy inside a pipe, two types of Phoswich detectors, sheets and cylinders, were prepared. For in-pipe monitoring, it was found that the cylindrical type was excellent. In the study, polymer composite counting material and Phoswich detectors were prepared using organic and inorganic scintillator for detecting different radiations. In the future, it will be applied to the contamination monitoring system for nuclear decommissioning sites, waste treatment sites, and similar areas. (authors)

  5. Alpha-particle diagnostics

    SciTech Connect

    Young, K.M.

    1991-01-01

    This paper will focus on the state of development of diagnostics which are expected to provide the information needed for {alpha}- physics studies in the future. Conventional measurement of detailed temporal and spatial profiles of background plasma properties in DT will be essential for such aspects as determining heating effectiveness, shaping of the plasma profiles and effects of MHD, but will not be addressed here. This paper will address (1) the measurement of the neutron source, and hence {alpha}-particle birth profile, (2) measurement of the escaping {alpha}-particles and (3) measurement of the confined {alpha}-particles over their full energy range. There will also be a brief discussion of (4) the concerns about instabilities being generated by {alpha}-particles and the methods necessary for measuring these effects. 51 refs., 10 figs.

  6. Event counting alpha detector

    DOEpatents

    Bolton, Richard D.; MacArthur, Duncan W.

    1996-01-01

    An electrostatic detector for atmospheric radon or other weak sources of alpha radiation. In one embodiment, nested enclosures are insulated from one another, open at the top, and have a high voltage pin inside and insulated from the inside enclosure. An electric field is produced between the pin and the inside enclosure. Air ions produced by collision with alpha particles inside the decay volume defined by the inside enclosure are attracted to the pin and the inner enclosure. With low alpha concentrations, individual alpha events can be measured to indicate the presence of radon or other alpha radiation. In another embodiment, an electrical field is produced between parallel plates which are insulated from a single decay cavity enclosure.

  7. Event counting alpha detector

    DOEpatents

    Bolton, R.D.; MacArthur, D.W.

    1996-08-27

    An electrostatic detector is disclosed for atmospheric radon or other weak sources of alpha radiation. In one embodiment, nested enclosures are insulated from one another, open at the top, and have a high voltage pin inside and insulated from the inside enclosure. An electric field is produced between the pin and the inside enclosure. Air ions produced by collision with alpha particles inside the decay volume defined by the inside enclosure are attracted to the pin and the inner enclosure. With low alpha concentrations, individual alpha events can be measured to indicate the presence of radon or other alpha radiation. In another embodiment, an electrical field is produced between parallel plates which are insulated from a single decay cavity enclosure. 6 figs.

  8. Imaging alpha particle detector

    DOEpatents

    Anderson, David F.

    1985-01-01

    A method and apparatus for detecting and imaging alpha particles sources is described. A conducting coated high voltage electrode (1) and a tungsten wire grid (2) constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source (3) to be quantitatively or qualitatively analyzed. A thin polyester film window (4) allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  9. Imaging alpha particle detector

    DOEpatents

    Anderson, D.F.

    1980-10-29

    A method and apparatus for detecting and imaging alpha particles sources is described. A dielectric coated high voltage electrode and a tungsten wire grid constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source to be quantitatively or qualitatively analyzed. A thin polyester film window allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  10. Reexamination of the {alpha}-{alpha}''fishbone'' potential

    SciTech Connect

    Day, J. P.; McEwen, J. E.; Elhanafy, M.; Smith, E.; Woodhouse, R.; Papp, Z.

    2011-09-15

    The fishbone potential of composite particles simulates the Pauli effect by nonlocal terms. We determine the {alpha}-{alpha} fishbone potential by simultaneously fitting to two-{alpha} resonance energies, experimental phase shifts, and three-{alpha} binding energies. We found that, essentially, a simple Gaussian can provide a good description of two-{alpha} and three-{alpha} experimental data without invoking three-body potentials.

  11. Fission beta particles emitted into the geomagnetosphere. Memorandum report

    SciTech Connect

    Bendel, W.L.

    1982-04-15

    The spectrum of electrons emitted into the earth's magnetic field by an exoatmospheric nuclear burst is considerably more energetic than the spectrum of all delayed electrons from fission, a spectrum often used. A better electron spectrum for general use is presented. Some items are calculated, including a depth-dose curve, for the two spectra compared.

  12. The alpha channeling effect

    NASA Astrophysics Data System (ADS)

    Fisch, N. J.

    2015-12-01

    Alpha particles born through fusion reactions in a tokamak reactor tend to slow down on electrons, but that could take up to hundreds of milliseconds. Before that happens, the energy in these alpha particles can destabilize on collisionless timescales toroidal Alfven modes and other waves, in a way deleterious to energy confinement. However, it has been speculated that this energy might be instead be channeled into useful energy, so as to heat fuel ions or to drive current. Such a channeling needs to be catalyzed by waves Waves can produce diffusion in energy of the alpha particles in a way that is strictly coupled to diffusion in space. If these diffusion paths in energy-position space point from high energy in the center to low energy on the periphery, then alpha particles will be cooled while forced to the periphery. The energy from the alpha particles is absorbed by the wave. The amplified wave can then heat ions or drive current. This process or paradigm for extracting alpha particle energy collisionlessly has been called alpha channeling. While the effect is speculative, the upside potential for economical fusion is immense. The paradigm also operates more generally in other contexts of magnetically confined plasma.

  13. A new mechanism for DNA alterations induced by alpha particles such as those emitted by radon and radon progeny.

    PubMed Central

    Lehnert, B E; Goodwin, E H

    1997-01-01

    The mechanism(s) by which alpha (alpha) particles like those emitted from inhaled radon and radon progeny cause their carcinogenic effects in the lung remains unclear. Although direct nuclear traversals by alpha-particles may be involved in mediating these outcomes, increasing evidence indicates that a particles can cause alterations in DNA in the absence of direct hits to cell nuclei. Using the occurrence of excessive sister chromatid exchanges (SCE) as an index of DNA damage in human lung fibroblasts, we investigated the hypothesis that alpha-particles may induce DNA damage through the generation of extracellular factors. We have found that a relatively low dose of alpha-particles can result in the generation of extracellular factors, which, upon transfer to unexposed normal human cells, can cause excessive SCE to an extent equivalent to that observed when the cells are directly irradiated with the same irradiation dose. A short-lived, SCE-inducing factor(s) is generated in alpha-irradiated culture medium containing serum in the absence of cells. A more persistent SCE-inducing factor(s), which can survive freeze-thaw and is heat labile is produced by fibroblasts after exposure to the alpha-particles. These results indicate that the initiating target for alpha-particle-induced genetic changes can be larger than a cell's nucleus or even a whole cell. How transmissible factors like those observed here in vitro may extend to the in vivo condition in the context of a-particle-induced carcinogenesis in the respiratory tract remains to be determined. PMID:9400706

  14. Skeletal dosimetry models for alpha-particles for use in molecular radiotherapy

    NASA Astrophysics Data System (ADS)

    Watchman, Christopher J.

    Molecular radiotherapy is a cancer treatment methodology whereby a radionuclide is combined with a biologically active molecule to preferentially target cancer cells. Alpha-particle emitting radionuclides show significant potential for use in molecular radiotherapy due to the short range of the alpha-particles in tissue and their high rates of energy deposition. Current radiation dosimetry models used to assess alpha emitter dose in the skeleton were developed originally for occupational applications. In medical dosimetry, individual variability in uptake, translocation and other biological factors can result in poor correlation of clinical outcome with marrow dose estimates determined using existing skeletal models. Methods presented in this work were developed in response to the need for dosimetry models which account for these biological and patient-specific factors. Dosimetry models are presented for trabecular bone alpha particle dosimetry as well as a model for cortical bone dosimetry. These radiation transport models are the 3D chord-based infinite spongiosa transport model (3D-CBIST) and the chord-based infinite cortical transport model (CBICT), respectively. Absorbed fraction data for several skeletal tissues for several subjects are presented. Each modeling strategy accounts for biological parameters, such as bone marrow cellularity, not previously incorporated into alpha-particle skeletal dosimetry models used in radiation protection. Using these data a study investigating the variability in alpha-particle absorbed fractions in the human skeleton is also presented. Data is also offered relating skeletal tissue masses in individual bone sites for a range of ages. These data are necessary for dose calculations and have previously only been available as whole body tissue masses. A revised 3D-CBIST model is also presented which allows for changes in endosteum thickness to account for revised target cell location of tissues involved in the radiological induction of bone cancer. In addition, new data are presented on the location of bone-marrow stem cells within the marrow cavities of trabecular bone of the pelvis. All results presented in this work may be applied to occupational exposures, but their greatest utility lies in dose assessments for alpha-emitters in molecular radiotherapy.

  15. Alpha-1 Antitrypsin Deficiency

    MedlinePlus

    ... various organs. Individuals with Alpha-1 have a genetic disorder that prevents their body from creating enough of this protein. This trait must be inherited from both parents (who are, by definition, carriers) in order to cause the disorder. How ...

  16. Portable alpha spectrometer.

    PubMed

    Martn Snchez, A; de la Torre Prez, J

    2012-09-01

    Many portable devices have been designed to detect ?-rays or alpha and beta particles. Most of the ?-particle detectors give the total count as a result, without identifying the radionuclides existing in the sample. The development of a device allowing rapid and straightforward ?-particle spectrometry would be very useful for detecting the radioactive contents of unknown samples. This work describes the construction of a portable device using silicon semiconductor detectors designed to rapidly detect and possibly identify alpha-emitting radionuclides. PMID:22405957

  17. Alpha Particle Diagnostic

    SciTech Connect

    Fisher, Ray, K.

    2009-05-13

    The study of burning plasmas is the next frontier in fusion energy research, and will be a major objective of the U.S. fusion program through U.S. collaboration with our international partners on the ITER Project. For DT magnetic fusion to be useful for energy production, it is essential that the energetic alpha particles produced by the fusion reactions be confined long enough to deposit a significant fraction of their initial ~3.5 MeV energy in the plasma before they are lost. Development of diagnostics to study the behavior of energetic confined alpha particles is a very important if not essential part of burning plasma research. Despite the clear need for these measurements, development of diagnostics to study confined the fast confined alphas to date has proven extremely difficult, and the available techniques remain for the most part unproven and with significant uncertainties. Research under this grant had the goal of developing diagnostics of fast confined alphas, primarily based on measurements of the neutron and ion tails resulting from alpha particle knock-on collisions with the plasma deuterium and tritium fuel ions. One of the strengths of this approach is the ability to measure the alphas in the hot plasma core where the interesting ignition physics will occur.

  18. Diurnal testosterone and 17alpha-hydroxyprogesterone in peripheral plasma of young post-pubertal bulls. A study by frequent sampling.

    PubMed

    Thibier, M

    1976-03-01

    Testerone and 17alpha-hydroxyprogesterone were measured in the peripheral plasma of 6 young post-pubertal bulls of 1 year of age, by separate radioimmunoassays. Samples were collected every hour for 25 h at the beginning of each of four seasons. On a separate occasion blood samples were collected from one bull every 10 min for 2 h. As a result of the study, testosterone and 17alpha-hydroxyprogesterone appeared to be secreted episodically. These two steroid peaks showed good correlation. Each 24 h period showed its own characteristic pattern of pulsatile changes. Episodic secretion seems to be progressive rather than rapid and short lived. No real circadian rhythm was observed but at about 10.00 a.m. a trough in these steroid secretions occurred. This was followed by an increase in peripheral plasma concentration. These troughs occurred at all seasons after the morning feed and while semen was being collected in the performance test station. PMID:946351

  19. Genetics Home Reference: alpha thalassemia

    MedlinePlus

    ... four alpha-globin alleles results in alpha thalassemia trait. People with alpha thalassemia trait may have unusually small, pale red blood cells ... Hb Bart syndrome, HbH disease, or alpha thalassemia trait. The precise risk depends on how many alleles ...

  20. Learning about Alpha-1 Antitrypsin Deficiency (AATD)

    MedlinePlus

    ... terms used on this page Learning About Alpha-1 Antitrypsin Deficiency (AATD) What is alpha-1 antitrypsin ... for Alpha-1 Anttrypsin Deficiency What is alpha-1 antitrypsin defciency? Alpha-1 antitrypsin deficiency (AATD) is ...

  1. Antisense hypoxia-inducible factor-1alpha augments transcatheter arterial embolization in the treatment of hepatocellular carcinomas in rats.

    PubMed

    Sun, Xueying; Jiang, Hongchi; Jiang, Xian; Tan, Hongtao; Meng, Qinghui; Sun, Bei; Xu, Ruian; Krissansen, Geoffrey W

    2009-04-01

    Transcatheter arterial embolization (TAE) is a standard treatment for unresectable hepatic malignancies. It blocks the arterial blood supply to the tumor, but blockade of the blood supply can be short-lived as collateral blood vessels develop, leading to the failure of TAE. Here we report that intraportal delivery of adeno-associated viral (AAV) vectors expressing antisense hypoxia-inducible factor-1alpha (HIF-1alpha) (AAV-ASHIF) augments TAE to combat hepatocellular carcinoma (HCC). Intraportal delivery of AAV-ASHIF led to long-term localized expression of transgenic ASHIF in rat liver, and suppressed the growth of CBRH7919 HCC tumors established in rat liver by inhibiting the formation of neovessels and tumor cell proliferation. TAE therapy caused the necrosis and shrinkage of liver tumors; however, neovessels quickly formed and the residual tumors underwent rapid expansion. TAE enhanced tumor and liver hypoxia, which in turn upregulated expression of HIF-1alpha, vascular endothelial growth factor, glucose transporter-1, lactate dehydrogenase A, and proliferating cell nuclear antigen. Intraportal injection of AAV-ASHIF augmented the therapeutic effects of TAE and diminished its undesirable effects, resulting in extensive tumor cell death and suppression of the growth of liver tumors. In conclusion, this study has revealed that HIF-1 impedes the response of liver tumors to TAE. Antisense HIF-1alpha therapy is warranted as an approach for enhancing the efficacy of TAE to treat unresectable liver cancers. PMID:19327024

  2. Solar flare alpha particles

    NASA Technical Reports Server (NTRS)

    Lanzerotti, L. J.

    1973-01-01

    Interplanetary disturbances frequently change the instantaneous values of the low energy solar flare alpha-to-proton flux ratios. The fluxes of alpha particles were integrated over the duration of seven large solar events occurring between May 28, 1967, and November 6, 1969, in order to investigate the total alpha particles fluxes observed at 1 AU resulting from the flares. The spectra of the event integrated alphas are always softer than the spectra of the event integrated protons. As a consequence, the event-integrated alpha-to-proton ratios decrease slightly with increasing energy per nucleon. The He-4/H-1 ratios averaged over the seven events are found to vary as 0.026 (E/nucl) sup -0.2 in the range 1 to 10 MeV/nucleon. The value of the ratio at 1 MeV/nucleon is less than the helium-to-hydrogen abundance determined from spectroscopic studies of prominences and the chromosphere, and is less than the average solar wind helium-to-hydrogen abundance.

  3. Semiconductor polycrystalline alpha detectors

    NASA Astrophysics Data System (ADS)

    Schieber, M.; Roth, M.; Zuck, A.; Marom, G.; Khakhan, O.; Alfassi, Z. B.

    2006-08-01

    In order to check possible novel neutron detectors based on composite semiconductor detectors containing nuclides with large cross sections for neutron, we tested their response to alpha particles. In the present paper we describe results obtained with composite samples made of hexagonal Boron Nitride particles bound with Polystyrene or Nylon-6. The samples were tested under 5.5 MeV alpha particle radiation emitted from 241Am source and 4.8MeV alpha particle of 226Ra source. Some of the responses of these composite detectors to thermal neutrons were already reported and here we shall show some newer results obtained with thermal neutrons, from a low intensity 241Am - 9Be and also from a medium intensity 252Cf source, which were thermalized using 10 cm thick paraffin. The Alpha detection experiments show that all the tested samples, regardless of the binder, show a well-defined peak around the 270 energy channel. There was very little polarization of the alpha radiation, since the amplitude of the alpha peak is reduced after ~ 2min from start of the irradiation, from 100% to 95% and it stayed stable at this level for another 10 minutes. The alpha spectrum detected from a PbI II single crystal is also shown for comparison. The neutron spectrum obtained by the composite BN samples showed an apparent peak around the 150 energy channel. The Signal to noise ratio for neutron detection from radionuclide shown here is about 2 only, whereas recent results to be published later, obtained with our composite BN detectors from a neutron beam of about 10 7 sec -1cm -2 is ~2 5. The 1.4 and 1.7 MeV alpha peaks resulting from the nuclear reaction of thermal neutrons with 10B of the boron nitride detector are not buried in the noise range. The capacitance noise requires small contact areas, therefore for large area detectors it is necessary to produce an electronic read-out device which can add up a multitude of small (less than 10sq.mm) pixilated contacts.

  4. [Alpha-adrenoceptor antagonist (blocker)].

    PubMed

    Shigetomi, S

    1997-08-01

    Alpha adrenergic receptors localized in blood vessels, heart, and kidneys as well as pre- and post-synaptic membrane are significantly important for controlling blood pressure. The treatment of alpha-adrenoceptor blocking drugs induce vasodilatation subsequently lowering blood pressure. Selective alpha-1 adrenoceptor blocking drugs (alpha-1 blockers) are recommended as a first line treatment of hypertension, because of their desirable effect on lipid and glucose metabolism. alpha-1 blockers decrease in total cholesterol and triglycerides, and increase in HDL-cholesterol. It is suggested that alpha-1 blockers improve insulin tolerance, cardiomegaly and atherosclerosis. Although they have many beneficial effect, we should consider adverse effects (orthostatic hypotension, flushing, etc.). PMID:9284423

  5. [alpha]-Oxocarboxylic Acids

    ERIC Educational Resources Information Center

    Kerber, Robert C.; Fernando, Marian S.

    2010-01-01

    Several [alpha]-oxocarboxylic acids play key roles in metabolism in plants and animals. However, there are inconsistencies between the structures as commonly portrayed and the reported acid ionization constants, which result because the acids are predominantly hydrated in aqueous solution; that is, the predominant form is RC(OH)[subscript 2]COOH…

  6. [alpha]-Oxocarboxylic Acids

    ERIC Educational Resources Information Center

    Kerber, Robert C.; Fernando, Marian S.

    2010-01-01

    Several [alpha]-oxocarboxylic acids play key roles in metabolism in plants and animals. However, there are inconsistencies between the structures as commonly portrayed and the reported acid ionization constants, which result because the acids are predominantly hydrated in aqueous solution; that is, the predominant form is RC(OH)[subscript 2]COOH

  7. Biosynthesis of catalytically active rat testosterone 5. alpha. -reductase in microinjected Xenopus oocytes: Evidence for tissue-specific differences in translatable mRNA

    SciTech Connect

    Farkash, Y.; Soreq, H.; Orly, J. )

    1988-08-01

    The enzyme 4-ene-3-ketosteroid-5{alpha}-oxidoreductase plays a key role in androgen-dependent target tissues, where it catalyzes the conversion of testosterone to the biologically active dihydrotestosterone. The regulation of 5{alpha}-reductase expression has not been studied at the molecular level as the enzyme is a membrane protein that is labile in cell-free homogenates. The authors developed a sensitive bioassay of the enzyme activity expressed in Xenopus oocytes microinjected with rat liver and prostate mRNA. After microinjection, incubation of intact oocytes in the presence of ({sup 3}H)testosterone revealed the in ovo appearance of active 5{alpha}-reductase. Polyandenylylated RNA was fractionated by sucrose gradient centrifugation, and the enzymatic activity was shown to be encoded by a 1,600- to 2,000-base-pair fraction of hepatic poly(A){sup +} RNA. 5{alpha}-Reductase mRNA was most efficiently translated when up to 80 ng of RNA was injected per oocyte. In the injected oocytes, 5{alpha}-reductase mRNA was found to be a short-lived molecule whereas its in ovo translatable 5{alpha}-reductase protein exhibited stable enzymatic activity for over 40 hr. Moreover, the levels of translatable tissue-specific 5{alpha}-reductase mRNAs as monitored in the Xenopus oocytes correlated with the variable 5{alpha}-reductase activities in female rat liver, male rat liver, and prostate homogenates. Altogether, these results provide supporting evidence in favor of the transcriptional control of 5{alpha}-reductase expression in rat tissues.

  8. cap alpha. -. cap alpha. collisions at the CERN ISR

    SciTech Connect

    Symons, T.J.M.

    1982-09-01

    ..cap alpha..-..cap alpha.. and ..cap alpha..-p collisions have been studied at ..sqrt..s = 126 Gev/c and ..sqrt..s = 88 GeV, respectively, using colliding ..cap alpha..-particle and proton beams at the CERN intersecting storage rings. A brief review of the experimental results is given together with a discussion of future prospects in this field.

  9. Stereoselective Synthesis of [alpha, alpha][superscript ']-Biprolines

    SciTech Connect

    Vartak, Ashish P.; Young, Jr., Victor G.; Johnson, Rodney L.

    2010-11-10

    A means to induce dehydrodimerization of Seebach's oxazolidinone (5), the stereochemical outcome of which is entirely temperature dependent, is described. The resultant dimers 3 and 4 are precursors to (R,R)-alpha,alpha'-biproline (1) and meso-alpha,alpha'-biproline (2), respectively. An organohypobromite and an iminium halide are proposed to serve as electrophiles in the reaction with the enolate of 5 to give 3 and 4, respectively.

  10. Summary of Alpha Particle Transport

    SciTech Connect

    Medley, S.S.; White, R.B.; Zweben, S.J.

    1998-08-19

    This paper summarizes the talks on alpha particle transport which were presented at the 5th International Atomic Energy Agency's Technical Committee Meeting on "Alpha Particles in Fusion Research" held at the Joint European Torus, England in September 1997.

  11. Long-Term Stability of Planets in the Alpha Centauri System

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack; Quarles, Billy

    2015-01-01

    The alpha Centauri system is billions of years old, so planets are only expected to be found in regions where their orbits are long-lived. We evaluate the extent of the regions within the alpha Centauri AB star system where small planets are able to orbit for billion-year timescales, and we map the positions in the sky plane where planets on stable orbits about either stellar component may appear. We confirm the qualitative results of Wiegert & Holman (Astron. J. 113, 1445, 1997) regarding the approximate size of the regions of stable orbits of a single planet, which are larger for retrograde orbits relative to the binary than for pro-grade orbits. Additionally, we find that mean motion resonances with the binary orbit leave an imprint on the limits of orbital stability, and the effects of the Lidov-Kozai mechanism are also readily apparent. Overall, orbits of a single planet in the habitable zones near the plane of the binary are stable, whereas high-inclination orbits are short-lived. However, even well within regions where single planets are stable, multiple planet systems must be significantly more widely-spaced than they need to be around an isolated star in order to be long-lived.

  12. IPHAS: The INT/WFC Photometric H-alpha Survey of the Northern Galactic Plane

    NASA Astrophysics Data System (ADS)

    Walton, N. A.; Drew, J.; Barlow, M. J.; Corradi, R.; Drake, J.; Gaensicke, B.; Greimel, R.; Groot, P.; Irwin, M. J.; Knigge, C.; Leisy, P.; Lennon, D. J.; Mampaso, A.; Masheder, M.; Morris, R.; Parker, Q. A.; Phillipps, S.; Pretorius, M.; Rodriguez-Gil, P.; Skillen, I.; Sokoloski, J.; Steegs, D.; Unruh, Y.; Witham, A.; Zijlstra, A.; Zurita, A.; IPHAS Collaboration

    2004-12-01

    H-alpha emission both traces diffuse ionised nebulae and is commonly prominent in the spectra of pre- and post-main-sequence stars and interacting binaries. Since these are mostly relatively short-lived phases of evolution, they represent a minority of objects in a mature galaxy like our own at any one time. In the case of interacting binaries, they are simply hard to find. This scarcity, in turn, has acted as a brake on our understanding of these crucial evolutionary stages that, in youth, help shape the growth of planetary systems, and in old age, determine stellar end states along with the recycling of energy and chemically enriched matter back into the galactic environment. IPHAS is our H-alpha survey of the Northern Galactic Plane being carried out with the 2.5-m Isaac Newton telescope's Wide Field Camera. Some ˜1800 deg2 of the northern Galactic plane, over latitudes 5 < b < 5, is being imaged in H-alpha, r', i' to a depth of r' ˜20 mag. Here we report on the first 120 nights of observations. We comment on the advanced reduction pipeline employed to generate object catalogues. Early results are noted, including the discovery of a number of new, hitherto rare, quadropolar planetary nebulae. The IPHAS objects have been mined to select candidate samples for followup spectroscopic studies. Extreme emission line objects are selected from the (r' - H-alpha) v (r' - i') colour-colour plot. First detections of low mass young stars in the massive OB association Cyg OB2 are presented. We note how this data set will be a valuable resource for the emerging Virtual Observatory, and will be especially powerful when compared with matching multi-colour IR and optical surveys (e.g. 2MASS and SDSS).

  13. Mitigation of radiation nephropathy after internal {alpha}-particle irradiation of kidneys

    SciTech Connect

    Jaggi, Jaspreet Singh; Seshan, Surya V.; McDevitt, Michael R.; Sgouros, George; Hyjek, Elizabeth; Scheinberg, David A. . E-mail: d-scheinberg@ski.mskcc.org

    2006-04-01

    Purpose: Internal irradiation of kidneys as a consequence of radioimmunotherapy, radiation accidents, or nuclear terrorism can result in radiation nephropathy. We attempted to modify pharmacologically, the functional and morphologic changes in mouse kidneys after injection with the actinium ({sup 225}Ac) nanogenerator, an in vivo generator of {alpha}- and {beta}-particle emitting elements. Methods and Materials: The animals were injected with 0.35 {mu}Ci of the {sup 225}Ac nanogenerator, which delivers a dose of 27.6 Gy to the kidneys. Then, they were randomized to receive captopril (angiotensin-converting enzyme inhibitor), L-158,809 (angiotensin II receptor-1 blocker), spironolactone (aldosterone receptor antagonist), or a placebo. Results: Forty weeks after the {sup 225}Ac injection, the placebo-control mice showed a significant increase in blood urea nitrogen (BUN) (87.6 {+-} 6.9 mg/dL), dilated Bowman spaces, and tubulolysis with basement membrane thickening. Captopril treatment accentuated the functional (BUN 119.0 {+-} 4.0 mg/dL; p <0.01 vs. placebo controls) and histopathologic damage. In contrast, L-158,809 offered moderate protection (BUN 66.6 {+-} 3.9 mg/dL; p = 0.02 vs. placebo controls). Spironolactone treatment, however, significantly prevented the development of histopathologic and functional changes (BUN 31.2 {+-} 2.5 mg/dL; p <0.001 vs. placebo controls). Conclusions: Low-dose spironolactone and, to a lesser extent, angiotensin receptor-1 blockade can offer renal protection in a mouse model of internal {alpha}-particle irradiation.

  14. {alpha}-Decay half-lives, {alpha}-capture, and {alpha}-nucleus potential

    SciTech Connect

    Denisov, V. Yu. Khudenko, A.A.

    2009-11-15

    {alpha}-Decay half-lives and {alpha}-capture cross sections are evaluated in the framework of a unified model for {alpha}-decay and {alpha}-capture. In this model {alpha}-decay and {alpha}-capture are considered as penetration of the {alpha}-particle through the potential barrier formed by the nuclear, Coulomb, and centrifugal interactions between the {alpha}-particle and nucleus. The spins and parities of the parent and daughter nuclei as well as the quadrupole and hexadecapole deformations of the daughter nuclei are taken into account for evaluation of the {alpha}-decay half-lives. The {alpha}-decay half-lives for 344 nuclei and the {alpha}-capture cross sections of {sup 40}Ca, {sup 44}Ca, {sup 59}Co, {sup 208}Pb, and {sup 209}Bi agree well with the experimental data. The evaluated {alpha}-decay half-lives within the range of 10{sup -9}{<=}T{sub 1/2}{<=}10{sup 38} s for 1246 {alpha}-emitters are tabulated.

  15. Alpha Centauri A+B

    NASA Astrophysics Data System (ADS)

    Mohr, R.; Murdin, P.

    2000-11-01

    Alpha Centauri A and Alpha Centauri B comprise the closest BINARY SYSTEM to Earth. A third star, PROXIMA CENTAURI, is thought to be in orbit about the center of mass of Alpha Centauri A and B. Other common names for this binary include Rigel Kentaurus and Toliman....

  16. Short-lived isomers in {sup 94}Rb

    SciTech Connect

    Tsekhanovich, I.; Dare, J. A.; Smith, A. G.; Varley, B. J.; Simpson, G. S.; Urban, W.; Soldner, T.; Jolie, J.; Linnemann, A.; Orlandi, R.; Smith, J. F.; Scherillo, A.; Rzaca-Urban, T.; Zlomaniec, A.; Dorvaux, O.; Gall, B. J. P.; Roux, B.

    2008-07-15

    The medium-spin structure of the neutron-rich, odd-odd nucleus {sup 94}Rb was studied by means of {gamma}-ray spectroscopy. Excited levels were populated in the neutron-induced fission of {sup 235}U and in the spontaneous fission of {sup 252}Cf and {sup 248}Cm. Two isomeric states were found at 1485.2 and 2074.8 keV with half-lives of 18 and 107 ns, respectively. The probable structures of the two isomers involve the fully aligned, proton-neutron configurations [{pi}(g{sub 9/2}) x {nu}(g{sub 7/2})]{sub 8{sup +}} and [{pi}(g{sub 9/2}) x {nu}(h{sub 11/2})]{sub 10{sup -}}, respectively. These new data give information on the single-particle energies in the region.

  17. Harvard-MIT research program in short-lived radiopharmaceuticals

    SciTech Connect

    Adelstein, S.J.

    1991-01-01

    This report presents research on radiopharmaceuticals. The following topics are discussed: antibody labeling with positron-emitting radionuclides; antibody modification for radioimmune imaging; labeling antibodies; evaluation of technetium acetlyacetonates as potential cerebral blood flow agents; and studies in technetium chemistry. (CBS)

  18. Tropospheric Ozone as a Short-lived Chemical Climate Forcer

    NASA Technical Reports Server (NTRS)

    Pickering, Kenneth E.

    2012-01-01

    Tropospheric ozone is the third most important greenhouse gas according to the most recent IPCC assessment. However, tropospheric ozone is highly variable in both space and time. Ozone that is located in the vicinity of the tropopause has the greatest effect on climate forcing. Nitrogen oxides (NOx) are the most important precursors for ozone In most of the troposphere. Therefore, pollution that is lofted upward in thunderstorm updrafts or NOx produced by lightning leads to efficient ozone production in the upper troposphere, where ozone is most important climatically. Global and regional model estimates of the impact of North American pollution and lightning on ozone radiative forcing will be presented. It will be shown that in the Northern Hemisphere summer, the lightning effect on ozone radiative forcing can dominate over that of pollution, and that the radiative forcing signal from North America extends well into Europe and North Africa. An algorithm for predicting lightning flash rates and estimating lightning NOx emissions is being incorporated into the NASA GEOS-5 Chemistry and Climate Model. Changes in flash rates and emissions over an ENSO cycle and in future climates will be assessed, along with the resulting changes in upper tropospheric ozone. Other research on the production of NOx per lightning flash and its distribution in the vertical based on cloud-resolving modeling and satellite observations will be presented. Distributions of NO2 and O3 over the Middle East from the OMI instrument on NASA's Aura satellite will also be shown.

  19. On Al-26 and other short-lived interstellar radioactivity

    NASA Technical Reports Server (NTRS)

    Clayton, Donald D.; Hartmann, Dieter H.; Leising, Mark D.

    1993-01-01

    Several authors have shown that massive stars exploding at a rate of about three per century can account for a large portion, if not all, of the observed interstellar Al-26. In a separate argument using models of Galactic chemical evolution, Clayton (1984) showed that the Al-26/Al-27 production ratio was not large enough to maintain enough Al-26 in the Galactic disk gas of about 10 exp 10 solar masses having solar composition. We present a resolution of those conflicting arguments. A past history of Galactic infall growing the Galactic disk so dilutes the stable Al-27 concentration that the two approaches can be brought into near agreement. If massive stars dominate the production of Al-26, we suggest that the apparent shortfall of their Al-26/Al-27 yield ratio is to be interpreted as evidence for significant growth of the Galactic disk. We also discuss the implications of these arguments for other extinct radioactivities in meteorites, using I-129 and Sm-146 as examples.

  20. Short-lived Rn-222 daughters in cryogenic liquids

    SciTech Connect

    Pelczar, Krzysztof; Frodyma, Nikodem; Wójcik, Marcin

    2013-08-08

    In this paper a detection method of α emitters from {sup 222}Rn decay chain, present in cryogenic liquids, using bare Si-PIN diodes immersed in the liquids is presented. Properties of ionized {sup 222}Rn daughters deduced from conducted measurements are outlined. Life-time of positive ions was found to be of the order of 10 s, and nonzero content of electronegative ions was observed.

  1. Harvard--MIT research program in short-lived radiopharmaceuticals

    SciTech Connect

    Not Available

    1991-03-01

    This report describes progress on five projects. The first project showed a 1000 fold concentration of the cationic complex {sup 99m}Tc (MIBI) in heart cell mitochondria vs heart cell cytoplasm, as determined by high resolution electron probe microanalysis. Additional technetium-99m based complexes are being developed and tested. The second project involves evaluating technetium acetylacteonates as potential indicators of cerebral blood flow. An intermediate in the synthesis of a technetium porphyrin complex has been synthesized; an oxotechnetium(V)-2,4-pentanedione complex has been prepared and is currently being characterized. The third project involves using radio labelled antibodies for diagnosis and treatment of cancer. An early discovery was that chloramine-T based iodination protocols resulted in a reversal of the charge on mouse lgGs. Immunoperoxidase-labelled monoclonal antibody MOv 18 was shown to bind specifically to the most frequent ovarian aderon carcinomas, and not to healthy tissue, making this antibody a good candidate for immunotherapy or immunodetection. Work on a specific immunotherapy protocol suffered a setback when one reagent, a {sup 125}I-biotin complex, proved to be unstable in vivo. The fourth project involves labelling antibodies with positron emitting radionuclides. Radiofluorination was accomplished through reductive alkylation of {sup 18}F-aldehyde, or pentafluorophenyl esters. Radioiodination was accomplished using alkyl-tin derivation exchange. The fifth project examined antibody modification for use in radioimmune imaging. Technetium-99m-labelled lgG was shown to be biologically equivalent to Indium-III-labelled lgG for imaging focal sites of inflamation. Also, Indium III labelling of small bioactive peptides was examined as a means of imaging important physiological processes. 44 refs., 2 figs.

  2. Inorganic biochemistry with short-lived radioisotopes as nuclear probes

    NASA Astrophysics Data System (ADS)

    Trger, W.; Butz, T.

    2000-12-01

    Metal ions are ubiquitous in the biosphere. In living organisms metalloproteins with specifically designed metal cores perform vital chemical processes. On the other hand, several heavy metals are detrimental to living organisms and nature has developed effective enzymatic detoxification systems which convert toxic metal ions to less toxic species. The nuclear spectroscopy technique Time Differential Perturbed Angular Correlation (TDPAC) of ?-rays uses radioactive isotopes as nuclear probes in these metal cores to obtain a better understanding of the structural and functional significance of these metal cores by monitoring the nuclear quadrupole interaction of the TDPAC probe. Since this technique is based on the nuclear decay, it is also applicable under physiological conditions, i.e., especially at picomolar concentrations. For these studies an indispensable prerequisite is the production of the TDPAC probes with highest possible specific activity and purity as is done by the on-line mass separator ISOLDE at CERN in Geneva.

  3. Probing short-lived fluctuations in hadrons and nuclei

    SciTech Connect

    Munier, Stéphane

    2015-04-10

    We develop a picture of dipole-nucleus (namely dilute-dense) and dipole-dipole (dilute-dilute) scattering in the high-energy regime based on the analysis of the fluctuations in the quantum evolution. We emphasize the difference in the nature of the fluctuations probed in these two processes respectively, which, interestingly enough, leads to observable differences in the scattering amplitude profiles.

  4. Short-lived radionuclides in nuclear medicine - II

    SciTech Connect

    Budinger, T.F.; Peng, C.T.

    1985-11-01

    Positron emission tomography (PET) has been applied effectively in the diagnosis of Alzheimer's disease, the prognosis of stroke, and the evaluation of the efficacy of tumor therapy. In addition, PET has been applied to studies of the neuroreceptor distribution in the human brain, to studies of epilepsy and congenital disorders of the brain, and to the study of flow and metabolism of the human heart muscle. Of the many current investigations of PET, the three discussed here are now of clinical importance for patient care.

  5. Cyclotron targetry for production of short-lived positron emitters

    SciTech Connect

    Schlyer, D.J.

    1989-01-01

    The basic concepts of cyclotron target design are presented along with the relevant practical experience gained by workers in this field over the years. Results are presented from several recent studies on the temperature and density distribution inside gas and liquid targets. 5 refs., 3 figs.

  6. RAPID DETERMINATION OF 237 NP AND PU ISOTOPES IN WATER BY INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY AND ALPHA SPECTROMETRY

    SciTech Connect

    Maxwell, S.; Jones, V.; Culligan, B.; Nichols, S.; Noyes, G.

    2010-06-23

    A new method that allows rapid preconcentration and separation of plutonium and neptunium in water samples was developed for the measurement of {sup 237}Np and Pu isotopes by inductively-coupled plasma mass spectrometry (ICP-MS) and alpha spectrometry; a hybrid approach. {sup 238}U can interfere with {sup 239}Pu measurement by ICP-MS as {sup 238}UH{sup +} mass overlap and {sup 237}Np via peak tailing. The method provide enhanced removal of uranium by separating Pu and Np initially on TEVA Resin, then moving Pu to DGA resin for additional removal of uranium. The decontamination factor for uranium from Pu is almost 100,000 and the decontamination factor for U from Np is greater than 10,000. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration is performed using a streamlined calcium phosphate precipitation method. Purified solutions are split between ICP-MS and alpha spectrometry so that long and short-lived Pu isotopes can be measured successfully. The method allows for simultaneous extraction of 20 samples (including QC samples) in 4 to 6 hours, and can also be used for emergency response. {sup 239}Pu, {sup 242}Pu and {sup 237}Np were measured by ICP-MS, while {sup 236}Pu, {sup 238}Pu, and {sup 239}Pu were measured by alpha spectrometry.

  7. ORNL ALPHA MIS user's manual

    SciTech Connect

    Lovin, J.K.; Haese, R.L.; Lambdin, H.D.; Bowen, P.L.

    1984-06-01

    ALPHA is the most powerful and versatile of the Management Information Systems (MISs) sponsored and developed by the Finance and Materials Division of the Oak Ridge National Laboratory (ORNL). A general-purpose MIS, ALPHA can perform at least 75% of the common tasks required of MISs; it allows users to access any System 1022 data base on ORNL's PDP-10 computer to obtain information for use in the management process. This user's manual contains a description of the function of each ALPHA command and option. Besides the explanation of ALPHA's commands and options, this manual also contains a description of the ALPHA system, pointers on using ALPHA, an explanation of ALPHA's design in terms of its working vocabulary, and a sample problem.

  8. Alpha particles are extremely damaging to developing hemopoiesis compared to gamma irradiation

    SciTech Connect

    Tie-Nan Jiang ); Lord, B.I.; Hendry, J.H. )

    1994-03-01

    Estimates of risk of stochastic effects from contamination with [alpha]-particle-emitting radionuclides are based on equivalent doses which take into account the RBE of the high-LET radiation. It is assumed that the RBEs for deterministic effects are considerably less than those for stochastic effects. However, the offspring of mice injected with 30 Bq g[sup [minus]1] [sup 239]Pu at 13 days gestation develop a persistent deficit in hemopoietic stem cells which is primarily the result of damage to their regulatory microenvironment. Their spatial distribution in the marrow is also perturbed, and recent observations on those mice suggested a considerably higher factor than 20. To define a more realistic RBE for hemopoiesis, the effects of external [gamma] irradiation during the fetal development period have been compared directly with those of [sup 239]Pu incorporated via placental transfer on the development of hemopoietic tissue. Pregnant mice were irradiated with [sup 60]Co [gamma] rays (a) continuously from day 13 of gestation to birth at 0.15 or 0.6 Gy/day; (b) six repeated acute doses (0.6 Gy/min) at 0.1 or 0.3 Gy from day 13 of gestation; (c) one acute dose of 0.6 or 1.8 Gy on day 15 of gestation. The spatial distribution of hemopoietic stem cells in 8-week-old offspring was then determined and compared to that resulting from [alpha]-particle irradiation. In each case, the higher dose was required to match the results for [alpha] particles, suggesting an RBE for developing hemopoiesis of 250-360 compared to a continuous [gamma]-ray dose and a rather lower value of 130-180 compared to a single acute dose of [gamma] rays. This contrasts greatly to values for direct irradiation of the stem cells but argues that the effective RBE, measured for long-term effects in vivo, is the more realistic. It is concluded that an all-embracing factor can be grossly misleading and can greatly underestimate the risks of exposure to [alpha] particles. 21 refs., 3 figs., 1 tab.

  9. Finite Range Effects in (alpha, 2alpha) Reactions

    SciTech Connect

    Jain, Arun K.; Joshi, Bhushan N.

    2009-09-25

    Finite range calculations for the (alpha, 2alpha) reactions are performed for the first time to remove huge inconsistencies obtained earlier in conventional zero range analyses. Vagaries of the energy dependent experimental observations up to 200 MeV are understood using the well-established nuclear radii and distorting optical potentials. The results are found to be sensitive to the short distance behavior of the alpha-alpha interaction, indicating the utility of the knockout reactions as a probe of the knockout vertex at short distances. Our approach paves the way to include finite range effects in atomic and molecular physics as also in neutron multiplication calculations.

  10. Background canceling surface alpha detector

    DOEpatents

    MacArthur, D.W.; Allander, K.S.; Bounds, J.A.

    1996-06-11

    A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs.

  11. Background canceling surface alpha detector

    DOEpatents

    MacArthur, Duncan W.; Allander, Krag S.; Bounds, John A.

    1996-01-01

    A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone.

  12. High-Linear Energy Transfer Irradiation Targeted to Skeletal Metastases by the Alpha Emitter Ra-223: Adjuvant or Alternative to Conventional Modalities?

    SciTech Connect

    Bruland, Oyvind S.; Nilsson, Sten; Fisher, Darrell R.; Larsen, Roy H.

    2006-10-15

    The bone-seeking, alpha-particle emitting radiopharmaceutical Alpharadin, 223RaCl2 (t1/2 = 11.4 days) is under clinical development as a novel treatment for skeletal metastases from breast and prostate cancer. This paper summarizes the current status of preclinical and clinical research on 223RaCl2. Potential advantages of 223Ra to that of external beam irradiation or registered beta-emitting bone-seekers are discussed. Published data of 223Ra dosimetry in mice and a therapeutic study in a skeletal metastases model in nude rats have indicated significant therapeutic potential of bone-seeking alpha-emitters. This paper provides short-term and long-term results from the first clinical single dosage trial. We present data from a repeated dosage study of five consecutive injections of 50 kBq/kg bodyweight, once every third week, or two injections of 125 kBq/kg bodyweight, six weeks apart. Furthermore, preliminary results are given for a randomized phase II trial involving 64 patients with hormone-refractory prostate cancer and painful skeletal metastases who received four monthly injections of 223Ra or saline as an adjuvant to external beam radiotherapy. Also presented are preliminary dose estimates for 223Ra in humans. Results indicate that repeated dosing is feasible and that opportunities are available for combined treatment strategies.

  13. Drosophila melanogaster importin alpha1 and alpha3 can replace importin alpha2 during spermatogenesis but not oogenesis.

    PubMed Central

    Mason, D Adam; Fleming, Robert J; Goldfarb, David S

    2002-01-01

    Importin alpha's mediate the nuclear transport of many classical nuclear localization signal (cNLS)-containing proteins. Multicellular animals contain multiple importin alpha genes, most of which fall into three conventional phylogenetic clades, here designated alpha1, alpha2, and alpha3. Using degenerate PCR we cloned Drosophila melanogaster importin alpha1, alpha2, and alpha3 genes, demonstrating that the complete conventional importin alpha gene family arose prior to the split between invertebrates and vertebrates. We have begun to analyze the genetic interactions among conventional importin alpha genes by studying their capacity to rescue the male and female sterility of importin alpha2 null flies. The sterility of alpha2 null males was rescued to similar extents by importin alpha1, alpha2, and alpha3 transgenes, suggesting that all three conventional importin alpha's are capable of performing the important role of importin alpha2 during spermatogenesis. In contrast, sterility of alpha2 null females was rescued only by importin alpha2 transgenes, suggesting that it plays a paralog-specific role in oogenesis. Female infertility was also rescued by a mutant importin alpha2 transgene lacking a site that is normally phosphorylated in ovaries. These rescue experiments suggest that male and female gametogenesis have distinct requirements for importin alpha2. PMID:12019231

  14. Development of the MICROMEGAS detector for measuring the energy spectrum of alpha particles by using a 241Am source

    NASA Astrophysics Data System (ADS)

    Kim, Do Yoon; Ham, Cheolmin; Shin, Jae Won; Park, Tae-Sun; Hong, Seung-Woo; Andriamonje, Samuel; Kadi, Yacine; Tenreiro, Claudio

    2016-05-01

    We have developed MICROMEGAS (MICRO MEsh GASeous) detectors for detecting a particles emitted from an 241Am standard source. The voltage applied to the ionization region of the detector is optimized for stable operation at room temperature and atmospheric pressure. The energy of a particles from the 241Am source can be varied by changing the flight path of the a particle from the 241Am source. The channel numbers of the experimentally-measured pulse peak positions for different energies of the a particles are associated with the energies deposited by the alpha particles in the ionization region of the detector as calculated by using GEANT4 simulations; thus, the energy calibration of the MICROMEGAS detector for a particles is done. For the energy calibration, the thickness of the ionization region is adjusted so that a particles may completely stop in the ionization region and their kinetic energies are fully deposited in the region. The efficiency of our MICROMEGAS detector for a particles under the present conditions is found to be ~97.3%.

  15. Swelling induced by alpha decay in monazite and zirconolite ceramics: A XRD and TEM comparative study

    NASA Astrophysics Data System (ADS)

    Deschanels, X.; Seydoux-Guillaume, A. M.; Magnin, V.; Mesbah, A.; Tribet, M.; Moloney, M. P.; Serruys, Y.; Peuget, S.

    2014-05-01

    Zirconolite and monazite matrices are potential ceramics for the containment of actinides (Np, Cm, Am, Pu) which are produced over the reprocessing of spent nuclear fuel. Actinides decay mainly through the emission of alpha particles, which in turn causes most ceramics to undergo structural and textural changes (amorphization and/or swelling). In order to study the effects of alpha decays on the above mentioned ceramics two parallel approaches were set up. The first involved the use of an external irradiation source, Au, which allowed the deposited recoil energy to be simulated. The second was based on short-lived actinide doping with 238Pu, (i.e. an internal source), via the incorporation of plutonium oxide into both the monazite and zirconolite structures during synthesis. In both types of irradiation experiments, the zirconolite samples became amorphous at room temperature with damage close to 0.3 dpa; corresponding to a critical dose of 4 × 1018 α g-1 (i.e. ∼1.3 × 1021 keV cm-3). Both zirconolite samples also showed the same degree of macroscopic swelling at saturation (∼6%), with ballistic processes being the predominant damaging effect. In the case of the monazite however, the macroscopic swelling and amorphization were dependent on the nature of the irradiation. Externally, (Au), irradiated samples became amorphous while also demonstrating a saturation swelling of up to 8%. In contrast to this, the swelling of the 238Pu doped samples was much smaller at ∼1%. Also, unlike the externally (Au) irradiated monazite these 238Pu doped samples remained crystalline up to 7.5 × 1018 α g-1 (0.8 dpa). XRD, TEM and swelling measurements were used to fully characterize and interpret this behavior. The low swelling and the conservation of the crystalline state of 238Pu doped monazite samples indicates that alpha annealing took place within this material.

  16. Long range alpha particle detector

    DOEpatents

    MacArthur, Duncan W.; Wolf, Michael A.; McAtee, James L.; Unruh, Wesley P.; Cucchiara, Alfred L.; Huchton, Roger L.

    1993-01-01

    An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

  17. Polarization bremsstrahlung in {alpha} decay

    SciTech Connect

    Amusia, M. Ya.; Zon, B. A. Kretinin, I. Yu.

    2007-08-15

    A mechanism of formation of electromagnetic radiation that accompanies {alpha} decay and is associated with the emission of photons by electrons of atomic shells due to the scattering of {alpha} particles by these atoms (polarization bremsstrahlung) is proposed. It is shown that, when the photon energy is no higher than the energy of K electrons of an atom, polarization bremsstrahlung makes a significant contribution to the bremsstrahlung in {alpha} decay.

  18. Long range alpha particle detector

    DOEpatents

    MacArthur, D.W.; Wolf, M.A.; McAtee, J.L.; Unruh, W.P.; Cucchiara, A.L.; Huchton, R.L.

    1993-02-02

    An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

  19. Modeling Solar Lyman Alpha Irradiance

    NASA Technical Reports Server (NTRS)

    Pap, J.; Hudson, H. S.; Rottman, G. J.; Willson, R. C.; Donnelly, R. F.; London, J.

    1990-01-01

    Solar Lyman alpha irradiance is estimated from various solar indices using linear regression analyses. Models developed with multiple linear regression analysis, including daily values and 81-day running means of solar indices, predict reasonably well both the short- and long-term variations observed in Lyman alpha. It is shown that the full disk equivalent width of the He line at 1083 nm offers the best proxy for Lyman alpha, and that the total irradiance corrected for sunspot effect also has a high correlation with Lyman alpha.

  20. Alpha particle confinement in tokamaks

    SciTech Connect

    White, R.B.; Mynick, H.E.

    1988-11-01

    An assessment of diffusive tokamak transport mechanisms of concern for alpha particles indicates that the ''stochastic regime'' is the only one which appears to pose a real danger for adequate alpha confinement. This fact, in conjunction with the threshold character of that mechanism, allows one to decide whether an alpha born at a given location will be lost or confined, according to a very simple criterion. Implementing this criterion numerically results in a new code for the assessment of alpha confinement, which is orders of magnitude faster than earlier codes used for this purpose. 13 refs., 3 figs., 1 tab.

  1. Alpha-1-acid glycoprotein.

    PubMed

    Fournier, T; Medjoubi-N, N; Porquet, D

    2000-10-18

    Alpha-1-acid glycoprotein (AGP) or orosomucoid (ORM) is a 41-43-kDa glycoprotein with a pI of 2.8-3.8. The peptide moiety is a single chain of 183 amino acids (human) or 187 amino acids (rat) with two and one disulfide bridges in humans and rats,respectively. The carbohydrate content represents 45% of the molecular weight attached in the form of five to six highly sialylated complex-type-N-linked glycans. AGP is one of the major acute phase proteins in humans, rats, mice and other species. As most acute phase proteins, its serum concentration increases in response to systemic tissue injury, inflammation or infection, and these changes in serum protein concentrations have been correlated with increases in hepatic synthesis. Expression of the AGP gene is controlled by a combination of the major regulatory mediators, i.e. glucocorticoids and a cytokine network involving mainly interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF alpha), interleukin-6 and IL-6 related cytokines. It is now well established that the acute phase response may take place in extra-hepatic cell types, and may be regulated by inflammatory mediators as observed in hepatocytes. The biological function of AGP remains unknown; however,a number of activities of possible physiological significance, such as various immunomodulating effects, have been described. AGP also has the ability to bind and to carry numerous basic and neutral lipophilic drugs from endogenous (steroid hormones) and exogenous origin; one to seven binding sites have been described. AGP can also bind acidic drugs such as phenobarbital. The immunomodulatory as well as the binding activities of AGP have been shown to be mostly dependent on carbohydrate composition. Finally, the use of AGP transgenic animals enabled to address in vivo, functionality of responsive elements and tissue specificity, as well as the effects of drugs that bind to AGP and will be an useful tool to determine the physiological role of AGP. PMID:11058758

  2. Resting alpha activity predicts learning ability in alpha neurofeedback

    PubMed Central

    Wan, Feng; Nan, Wenya; Vai, Mang I.; Rosa, Agostinho

    2014-01-01

    Individuals differ in their ability to learn how to regulate the brain activity by neurofeedback. This study aimed to investigate whether the resting alpha activity can predict the learning ability in alpha neurofeedback. A total of 25 subjects performed 20 sessions of individualized alpha neurofeedback and the learning ability was assessed by three indices respectively: the training parameter changes between two periods, within a short period and across the whole training time. It was found that the resting alpha amplitude measured before training had significant positive correlations with all learning indices and could be used as a predictor for the learning ability prediction. This finding would help the researchers in not only predicting the training efficacy in individuals but also gaining further insight into the mechanisms of alpha neurofeedback. PMID:25071528

  3. Alpha Magnetic Spectrometer

    NASA Astrophysics Data System (ADS)

    Ting, Samuel

    2012-07-01

    The Alpha Magnetic Spectrometer (AMS) is a precision particle physics magnetic spectrometer designed to measure electrons, positrons, gamma rays and various nuclei and anti-nuclei from the cosmos up to TeV energy ranges. AMS weighs 7.5 tons and measures 5 meters by 4 meters by 3 meters. It contains 300,000 channels of electronics and 650 onboard microprocessors. It was delivered to the International Space Station onboard space shuttle Endeavour and installed on May 19, 2011. Since that time, more than 14 billion cosmic ray events have been collected. All the detectors function properly. At this moment, we are actively engaged in data analysis. AMS is an international collaboration involving 16 countries and 60 institutes. It took 16 years to construct and test. AMS is the only major physical science experiment on the International Space Station and will continue to collect data over the entire lifetime of the Space Station (10-20 years).

  4. Microscopic cluster model of {alpha}+n, {alpha}+p, {alpha}+ {sup 3}He, and {alpha}+{alpha} elastic scattering from a realistic effective nuclear interaction

    SciTech Connect

    Dohet-Eraly, J.; Baye, D.

    2011-07-15

    An effective nucleon-nucleon interaction adapted to cluster-model calculations of collisions is derived from the realistic Argonne potential AV18 with the unitary correlation operator method. The unitary correlation is determined from the {alpha}+{alpha} elastic phase shifts calculated in a cluster approach by the generator coordinate method coupled with the microscopic R-matrix method. With this interaction, the elastic phase shifts for the {alpha}+n, {alpha}+p, and {alpha}+{sup 3}He collisions are calculated within the same model. Without further adjustment, a good agreement with experimental data is obtained with a small model space.

  5. DFT CONFORMATIONAL STUDIES OF ALPHA-MALTOTRIOSE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent DFT optimization studies on alpha-maltose improved our understanding of the preferred conformations of alpha-maltose and the present study extends these studies to alpha-maltotriose with three alpha-D-glucopyranose residues linked by two alpha-[1-4] bridges, denoted herein as DP-3's. Combina...

  6. Prompt detection of alpha particles from 210Po: another clue to the origin of rock varnish?

    PubMed

    Hodge, Vernon F; Farmer, Dennis E; Diaz, Tammy; Orndorff, Richard L

    2005-01-01

    Alpha particles have been measured coming from the surfaces of rocks covered with dark red-brown rock varnish, as well as rocks that appear to have little, if any, varnish. A pronounced peak at 5.3 MeV indicates the presence of 210Po, a short-lived natural-radioactive element. Surface activities for 33 samples range from 0.008 Bq/cm2 to 0.065 Bq/cm2. It is estimated that this nuclide is concentrated 10(11) times in these paper-thin coatings above its concentration in ground-level air. Gamma rays from the decay of 137Cs, a product of testing nuclear weapons some 50 years ago, were also detected. Analysis of samples of varnish stripped from the rock revealed traces of 239,240Pu and 238Pu. The presence of all of these isotopes strongly supports the theory that varnish films derive their building blocks from the atmosphere and, with time, all rocks in arid environments will become coated. PMID:15511566

  7. Chromosomal aberrations of blood lymphocytes induced in vitro by radon-222 daughter alpha-irradiation.

    PubMed

    Pohl-Rüling, J; Lettner, H; Hofmann, W; Eckl, P; Haas, O A; Obe, G; Grell-Büchtmann, I; van Buul, P P; Schroeder-Kurth, T; Atzmüller, C; Sasaki, M S; Fischer, P; Kubiak, R; Natarajan, A T

    2000-04-01

    Blood samples were irradiated in vitro with alpha-rays emitted from short-lived radon decay products dissolved in the culture medium at doses between 0.03 and 41.4 mGy. The data were collected from experiments conducted during the period 1984-1992 and comprise a total of about 64000 scored metaphases. For statistical reasons, only 60,022 metaphases were used for the subsequent analysis. The results for total chromosome aberrations and dicentrics indicate a linear dose dependence in the dose range above about 10 mGy, consistent with other experimental observations. At doses below about 10 mGy, aberration frequencies cannot be linearly extrapolated from higher doses, suggesting that there is no dependence on dose within a certain low-dose range. In addition, a statistically significant minimum has been observed at a dose of about 0.03 mGy, which is consistently lower than the related control values. The behavior of the aberration frequencies in the low-dose region seems to be influenced by the control values, which also depend on the environmental radiation burdens to the donors before blood sampling and thus were significantly affected by the Chernobyl fallout. PMID:10751630

  8. Learning about Alpha-1 Antitrypsin Deficiency (AATD)

    MedlinePlus

    ... disease in children and adults. Alpha-1 Association Genetic Counseling Service [alpha1.org] The Alpha-1 Association Genetic Counseling Center provides toll-free, confidential genetic counseling to ...

  9. THE COMPLEX FATE OF ALPHA-KETOACIDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant cells are unique in that they contain four species of alpha-ketoacid dehydrogenase complex: plastidial pyruvate dehydrogenase, mitochondrial pyruvate dehydrogenase, alpha-ketoglutarate (2-oxoglutarate) dehydrogenase, and branched-chain alpha-ketoacid dehydrogenase. All complexes include multi...

  10. Alpha-particle spectrometer experiment

    NASA Technical Reports Server (NTRS)

    Gorenstein, P.; Bjorkholm, P.

    1972-01-01

    Mapping the radon emanation of the moon was studied to find potential areas of high activity by detection of radon isotopes and their daughter products. It was felt that based on observation of regions overflown by Apollo spacecraft and within the field of view of the alpha-particle spectrometer, a radon map could be constructed, identifying and locating lunar areas of outgassing. The basic theory of radon migration from natural concentrations of uranium and thorium is discussed in terms of radon decay and the production of alpha particles. The preliminary analysis of the results indicates no significant alpha emission.

  11. Prothymosin alpha receptors on lymphocytes.

    PubMed

    Cordero, O J; Sarandeses, C; Nogueira, M

    1995-08-01

    Recent results indicate that prothymosin alpha (ProT alpha) may be useful in designing future therapeutic interventions in cancer patients and in potentiating the immune system. We described recently the presence and characteristics of two binding sites for ProT alpha on human peripheral blood mononuclear cells (PBMC). In search of a receptor upregulation, we decided to corroborate this finding on two lymphocytic populations, (PHA-activated) lymphoblasts and YT cells. The kinetics of [125I]ProT alpha binding to lymphoblasts were fast at room temperature but with YT cells were slower. Analysis of steady-state binding data identified two binding sites in lymphoblasts with an apparent equilibrium Kd of 44-75 pM and 4228-9143 sites per cell for the high-affinity receptor and 1.7-2.9 nM and 20,534-35,044 sites per cell for the low-affinity receptor. However, it identified only one site with a Kd of 265-435 pM and 8318-27,237 sites per cell in YT cells. We conclude that exists a ProT alpha receptor in the CD3+ T cell population, and this presence is regulated. After binding to cell surface, [125I]ProT alpha is internalized in a short period of time and then degraded; therefore, we conclude that the dynamics of ProT alpha receptor turnover in part determines the concentration of ProT alpha available to induce its enhancing effects. PMID:8528946

  12. Radon and Thoron Measured in Petrol and Gas-oil Exhaust Fumes by Using CR-39 and LR-115 II Nuclear Track Detectors: Radiation Doses to the Respiratory Tract of Mechanic Workers.

    PubMed

    Misdaq, M A; Chaouqi, A; Ouguidi, J; Touti, R; Mortassim, A

    2015-06-01

    Mechanic workers are exposed to exhaust fumes when controlling vehicle engines in motion inside repair shops. To assess radiation doses due to radon short-lived progeny from the inhalation of exhaust fumes by mechanic workers, concentrations of these radionuclides were measured in petrol (gasoline) and gas-oil exhaust fumes by evaluating mean critical angles of etching of the CR-39 and LR-115 type II SSNTDs for alpha particles emitted by the radon and thoron decay series. Committed effective doses due to ²¹⁸Po and ²¹⁴Po short-lived radon decay products from the inhalation of petrol and gas-oil exhaust fumes by workers were evaluated. A maximum value of 1.35 mSv y⁻¹ due to radon short-lived decay products from the inhalation of gas-oil exhaust fumes by mechanic workers was found, which is lower than the (3-10 mSv y⁻¹) dose limit interval for workers. PMID:25905520

  13. I. Excluded Volume Effects in Ising Cluster Distributions and Nuclear Multifragmentation II. Multiple-Chance Effects in Alpha-Particle Evaporation

    SciTech Connect

    Breus, Dimitry E.

    2005-05-16

    In Part 1, geometric clusters of the Ising model are studied as possible model clusters for nuclear multifragmentation. These clusters may not be considered as non-interacting (ideal gas) due to excluded volume effect which predominantly is the artifact of the cluster's finite size. Interaction significantly complicates the use of clusters in the analysis of thermodynamic systems. Stillinger's theory is used as a basis for the analysis, which within the RFL (Reiss, Frisch, Lebowitz) fluid-of-spheres approximation produces a prediction for cluster concentrations well obeyed by geometric clusters of the Ising model. If thermodynamic condition of phase coexistence is met, these concentrations can be incorporated into a differential equation procedure of moderate complexity to elucidate the liquid-vapor phase diagram of the system with cluster interaction included. The drawback of increased complexity is outweighted by the reward of greater accuracy of the phase diagram, as it is demonstrated by the Ising model. A novel nuclear-cluster analysis procedure is developed by modifying Fisher's model to contain cluster interaction and employing the differential equation procedure to obtain thermodynamic variables. With this procedure applied to geometric clusters, the guidelines are developed to look for excluded volume effect in nuclear multifragmentation. In part 2, an explanation is offered for the recently observed oscillations in the energy spectra of {alpha}-particles emitted from hot compound nuclei. Contrary to what was previously expected, the oscillations are assumed to be caused by the multiple-chance nature of {alpha}-evaporation. In a semi-empirical fashion this assumption is successfully confirmed by a technique of two-spectra decomposition which treats experimental {alpha}-spectra has having contributions from at least two independent emitters. Building upon the success of the multiple-chance explanation of the oscillations, Moretto's single-chance evaporation theory is augmented to include multiple-chance emission and tested on experimental data to yield positive results.

  14. 21 CFR 882.1610 - Alpha monitor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Alpha monitor. 882.1610 Section 882.1610 Food and... NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An alpha... electroencephalogram which is referred to as the alpha wave. (b) Classification. Class II (performance standards)....

  15. 21 CFR 882.1610 - Alpha monitor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Alpha monitor. 882.1610 Section 882.1610 Food and... NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An alpha... electroencephalogram which is referred to as the alpha wave. (b) Classification. Class II (performance standards)....

  16. Circulating integrins: alpha 5 beta 1, alpha 6 beta 4 and Mac-1, but not alpha 3 beta 1, alpha 4 beta 1 or LFA-1.

    PubMed Central

    Bretscher, M S

    1992-01-01

    The alpha 5 beta 1, alpha 6 beta 4 and Mac-1 integrins all participate in the endocytotic cycle. By contrast, alpha 3 beta 1, alpha 4 beta 1 and LFA-1 do so much more slowly, or not at all, in the cell lines examined. This indicates that the alpha-chains appear to determine whether an integrin cycles or not, and that alpha 5 beta 1, alpha 6 beta 4 and Mac-1 can be brought to the leading edge of a moving cell by endocytosis and recycling. Images PMID:1531629

  17. Binding of actin to lens alpha crystallins

    NASA Technical Reports Server (NTRS)

    Gopalakrishnan, S.; Takemoto, L.; Spooner, B. S. (Principal Investigator)

    1992-01-01

    Actin has been coupled to a cyanogen bromide-activated Sepharose 4B column, then tested for binding to alpha, beta, and gamma crystallin preparations from the bovine lens. Alpha, but not beta or gamma, crystallins bound to the actin affinity column in a time dependent and saturable manner. Subfractionation of the alpha crystallin preparation into the alpha-A and alpha-B species, followed by incubation with the affinity column, demonstrated that both species bound approximately the same. Together, these studies demonstrate a specific and saturable binding of lens alpha-A and alpha-B with actin.

  18. Mechanism of alpha-tocopheryl-phosphate (alpha-TP) transport across the cell membrane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have reported that alpha-TP is synthesized and hydrolyzed in animal cells and tissues; it modulates also several cell functions (FRBM 39:970, and UBMB Life, 57:23, 2005). While it is similar to alpha-tocopherol (alpha-T), alpha-TP appears to be more potent than alpha-T in inhibiting cell prolifer...

  19. Biotransformation of 3alpha,4alpha-dihydroxy-dihydro-beta-agarofuran by Rhizopus nigricans.

    PubMed

    Alarcón, Julio; Aguila, Sergio

    2004-01-01

    3alpha,4alpha-Dihydroxy-dihydro-beta-agarofuran (1), prepared from (+)-dihydrocarvone by a traditional synthetic method, the Robinson annelation, was biotransformed by R. nigricans to afford a new metabolite characterized as 1alpha,3alpha,4alpha-trihydroxy-dihydro-beta-agarofuran (2) by spectroscopic method. An acetylated derivative was prepared. PMID:15241929

  20. Modulation of gene expression by alpha-tocopherol and alpha-tocopheryl phosphate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The naturally occurring vitamin E analogue, alpha-tocopheryl phosphate (alphaTP), has been reported to be more potent in reducing cell proliferation and the expression of the CD36 scavenger receptor than the un-phosphorylated alpha-tocopherol (alpha T). We have now assessed the effects of alpha T an...

  1. Workshop on Precision Measurements of $\\alpha_s$

    SciTech Connect

    Bethke, Siegfried; Hoang, Andre H.; Kluth, Stefan; Schieck, Jochen; Stewart, Iain W.; Aoki, S.; Beneke, M.; Bethke, S.; Blumlein, J.; Brambilla, N.; Brodsky, S.; /MIT, LNS

    2011-10-01

    These are the proceedings of the Workshop on Precision Measurements of {alpha}{sub s} held at the Max-Planck-Institute for Physics, Munich, February 9-11, 2011. The workshop explored in depth the determination of {alpha}{sub s}(m{sub Z}) in the {ovr MS} scheme from the key categories where high precision measurements are currently being made, including DIS and global PDF fits, {tau}-decays, electro-weak precision observables and Z-decays, event-shapes, and lattice QCD. These proceedings contain a short summary contribution from the speakers, as well as the lists of authors, conveners, participants, and talks.

  2. Time evolution of a miniflare as seen in H-alpha, UV lines, and X-rays

    NASA Technical Reports Server (NTRS)

    Fontenla, J.; Schmieder, B.; Simnett, G. M.; Tandberg-Hanssen, E.

    1994-01-01

    A miniflare that occurred in active region Hale 16896 on 1980 June 15 was observed in H-alpha, UV lines, and soft X-rays. These data allow us to analyze the flare emission and derive the energetics and dynamics of the chromospheric plasma involved. Our results indicate that the energy released by the miniflare was about 10(exp 28) ergs, about four orders of magnitude smaller than that of a large flare. However, hard X-rays (5.5-8.0 keV) were observed which indicated a plasma with temperature as high as 27 x 10(exp 6) K. The H-alpha wings, C IV, and X-rays all showed a short-lived and compact (3 sec x 3 sec) brightening in a location near the leading sunspot. At this location, small-scale changes in the magnetic field were observed from about 2 hr before to about 6 hr after the miniflare. Only very small velocities seem to have been associated with most of the event in H-alpha. The data are consistent with short and dense loops at temperatures above 10(exp 7) K which lost a large fraction of their energy via downward conduction through regions at the footpoints. Several secondary events appear to have been triggered by the miniflare along an arch filament which itself was not greatly affected. A number of much less energetic (10(exp 25)-10(exp 26) erg) events preceded and followed the mini-flare. One of these occurred 11 minutes after the mini-flare and displayed a highly Doppler-shifted signature from the foot-point of a C IV arch. This arch delineates the connection that existed between the location of the mini-flare and the location of secondary events triggered by the flare.

  3. Alpha thalassaemia in British people.

    PubMed Central

    Higgs, D R; Ayyub, H; Clegg, J B; Hill, A V; Nicholls, R D; Teal, H; Wainscoat, J S; Weatherall, D J

    1985-01-01

    Although alpha thalassaemia is rare in north Europeans, it has been identified in British people with no known foreign ancestry. Twelve such patients were studied, of whom eight shared a distinctive molecular defect, which was clearly different from defects seen in subjects of Mediterranean or South East Asian origin. A rare but specific form of alpha thalassaemia is therefore present in the British population. In addition, two patients from families of mixed racial origin were encountered who had a moderately severe form of thalassaemia (HbH disease) due to the inheritance of one form of alpha thalassaemia from the British parent and another type from the foreign parent. This shows the importance of careful genetic counselling of British patients with haematological findings of thalassaemia. Images FIG 3 PMID:2986751

  4. ALPHA: antihydrogen and fundamental physics

    NASA Astrophysics Data System (ADS)

    Madsen, Niels

    2014-02-01

    Detailed comparisons of antihydrogen with hydrogen promise to be a fruitful test bed of fundamental symmetries such as the CPT theorem for quantum field theory or studies of gravitational influence on antimatter. With a string of recent successes, starting with the first trapped antihydrogen and recently resulting in the first measurement of a quantum transition in anti-hydrogen, the ALPHA collaboration is well on its way to perform such precision comparisons. We will discuss the key innovative steps that have made these results possible and in particular focus on the detailed work on positron and antiproton preparation to achieve antihydrogen cold enough to trap as well as the unique features of the ALPHA apparatus that has allowed the first quantum transitions in anti-hydrogen to be measured with only a single trapped antihydrogen atom per experiment. We will also look at how ALPHA plans to step from here towards more precise comparisons of matter and antimatter.

  5. Space Station alpha joint bearing

    NASA Technical Reports Server (NTRS)

    Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

    1987-01-01

    Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

  6. NACA Physicist Studying Alpha Rays

    NASA Technical Reports Server (NTRS)

    1957-01-01

    NACA Physicits studying Alpha Rays in a continuous cloud chamber. A cloud chamber is used by Lewis scientists to obtain information aimed at minimizing undesirable effects of radiation on nuclear-powered aircraft components. Here, alpha particles from a polonium source emit in a flower-like pattern at the cloud chamber's center. The particles are made visible by means of alcohol vapor diffusing from an area at room temperature to an area at minus -78 deg. Centigrade. Nuclear-powered aircraft were never developed and aircraft nuclear propulsion systems were canceled in the early 1960s.

  7. Bremsstrahlung in {alpha} Decay Reexamined

    SciTech Connect

    Boie, H.; Scheit, H.; Jentschura, U. D.; Koeck, F.; Lauer, M.; Schwalm, D.; Milstein, A. I.; Terekhov, I. S.

    2007-07-13

    A high-statistics measurement of bremsstrahlung emitted in the {alpha} decay of {sup 210}Po has been performed, which allows us to follow the photon spectra up to energies of {approx}500 keV. The measured differential emission probability is in good agreement with our theoretical results obtained within the quasiclassical approximation as well as with the exact quantum mechanical calculation. It is shown that, due to the small effective electric dipole charge of the radiating system, a significant interference between the electric dipole and quadrupole contributions occurs, which is altering substantially the angular correlation between the {alpha} particle and the emitted photon.

  8. Test chamber for alpha spectrometry

    DOEpatents

    Larsen, Robert P.

    1977-01-01

    Alpha emitters for low-level radiochemical analysis by measurement of alpha spectra are positioned precisely with respect to the location of a surface-barrier detector by means of a chamber having a removable threaded planchet holder. A pedestal on the planchet holder holds a specimen in fixed engagement close to the detector. Insertion of the planchet holder establishes an O-ring seal that permits the chamber to be pumped to a desired vacuum. The detector is protected against accidental contact and resulting damage.

  9. Long-range alpha detector sample monitoring

    NASA Astrophysics Data System (ADS)

    Johnson, J. D.; Allander, K. S.; Bounds, J. A.; Garner, S. E.; Johnson, J. P.; MacArthur, D. W.; Sprouse, L. L.; Walters, S. G.

    1994-12-01

    Long-range alpha detector (LRAD) systems are designed to monitor alpha sources and contamination by measuring the number of ions created in air by ionizing radiation. Traditional alpha detectors are designed to detect alpha particles directly and must be passed slowly within about 3 cm of an alpha source to operate effectively. LRAD detectors collect the ions created from alpha interactions with air. Therefore, they are better able to monitor equipment and complex surfaces and can be operated at a much greater distance from an alpha source than traditional alpha detectors. Furthermore, because LRAD detectors remain stationary during monitoring, they are less subject to operator error than traditional alpha detectors. This paper will discuss the basic operation as well as recent advances that have been made to LRAD Sample Monitors.

  10. Meet the Alpha-Pets.

    ERIC Educational Resources Information Center

    Zitlaw, Jo Ann Bruce; Frank, Cheryl Standish

    1985-01-01

    "Alpha-Pets" are the focal point of an integrated, multidisciplinary curriculum. Each pet is featured for a week in a vocabulary-rich story and introduces related activities beginning with the featured letter, such as the four food groups during Freddie Fish's week or universe during Ulysses Unicorn's week. (MT)

  11. Alcoholism, Alpha Production, and Biofeedback

    ERIC Educational Resources Information Center

    Jones, Frances W.; Holmes, David S.

    1976-01-01

    Electroencephalograms of 20 alcoholics and 20 nonalcoholics were obtained. Data indicated that alcoholics produced less alpha than nonalcoholics. In one training condition subjects were given accurate biofeedback, whereas in the other condition subjects were given random (noncontingent) feedback. Accurate biofeedback did not result in greater…

  12. Alpha Testing Escape from Diab

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alpha testing was conducted of sessions 2 and 3 from Diab to assess whether the activities worked as expected, and whether children in the target ages enjoyed it. Data include both RA observations of child performance while playing the games and cognitive interview responses from the players after t...

  13. Alpha proton x ray spectrometer

    NASA Technical Reports Server (NTRS)

    Rieder, Rudi; Waeke, H.; Economou, T.

    1994-01-01

    Mars Pathfinder will carry an alpha-proton x ray spectrometer (APX) for the determination of the elemental chemical composition of Martian rocks and soils. The instrument will measure the concentration of all major and some minor elements, including C, N, and O at levels above typically 1 percent.

  14. Cloning and expression of metallothionein mutant alpha-KKS-alpha in Anabaena sp. PCC 7120.

    PubMed

    Shao, Qiang; Shi, Ding-Ji; Hao, Fu-Ying; Ma, Li-Na; Chen, Zhen-Jia; Yu, Mei-Min; Ru, Bing-Gen

    2002-01-01

    The mouse metallothionein (mMT) mutant alpha-KKS-alpha has a higher capacity for binding heavy metals than wild type mMT. The mMT mutant alpha-KKS-alpha gene was placed under the control of the strong promoter PpbsA to generate the intermediate vector pRL-alpha-KKS-alpha. pRLalpha-KKS-alpha was then linked with the plasmid pDC-08 to construct shuttle expression vector pDC-alphaKKS-alpha. This expression vector was transformed into Anabaena sp. PCC 7120 using triparental conjugative transfer. After antibiotic selection (ampicillin and kanamycin), transgenic Anabaena was identified by PCR and Western blotting. The expression level of the mMT mutation alpha-KKS-alpha reached 7.4 mg/g dry cells weight, as detected by ELISA, and heavy metal resistance of the transgenic Anabaena was significantly improved. PMID:12398381

  15. THE CYCLES OF {alpha} CENTAURI

    SciTech Connect

    Ayres, Thomas R.

    2009-05-10

    The main AB pair of the nearby {alpha} Centauri triple system has one of the most extensive X-ray records of any cosmic object, stretching over 30 years. The primary, {alpha} Cen A (G2 V), is a near twin of the Sun, with a similarly soft (1-2 MK) corona. The secondary, {alpha} Cen B (K1 V), is more active than the Sun, with a generally harder coronal spectrum. Here, more than a decade of spatially resolved measurements from ROSAT, XMM-Newton, and Chandra are compared on a common basis, with careful attention to conversion factors that translate count rates of the different instruments into absolute energy fluxes. For the latter purpose, two epochs of Chandra transmission grating spectra, which fully resolve the binary, were modeled using a differential emission measure formalism. The aggregate time series suggests that {alpha} Cen B was near X-ray maximum in the mid-1990s, minimum in the late-1990s, then peaked again in 2004-2005, and more recently has been declining toward another minimum. Meanwhile, {alpha} Cen A showed minimal variability 1995-2000, and like the secondary presently is mired in an activity lull (in fact, as seen by XMM-Newton, the primary 'fainted' from view in the 2005 time frame). Comparisons between X-ray luminosities in the 0.2-2 keV (6-60 A) ROSAT 'WGACAT' band and a softer counterpart 0.06-1.2 keV (10-200 A) reinforce the idea that cycle depth is strongly dependent on the energy span of the measurement, and that much of the coronal luminosity of cool-corona objects like the Sun falls at longer wavelengths than are recorded efficiently by contemporary instruments. Consequently, one must be careful in discussing X-ray cycles, their amplitudes, and coronal heating requirements unless one can demonstrate good control over the out-of-band component.

  16. Modulation of gene expression by alpha-tocopherol and alpha-tocopheryl phosphate in thp-1 monocytes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The naturally occurring vitamin E analogue, alpha-tocopheryl phosphate (alphaTP), has been reported to be more potent than the un-phosphorylated alpha alpha-tocopherol (alphaT). We have now measured plasma levels of alphaTP and compared the cellular effects of alphaTP and gamma-tocopheryl phosphate ...

  17. Coexistence of {alpha}+{alpha}+n+n and {alpha}+t+t cluster structures in {sup 10}Be

    SciTech Connect

    Itagaki, N.; Ito, M.; Milin, M.; Hashimoto, T.; Ishiyama, H.; Miyatake, H.

    2008-06-15

    The coexistence of the {alpha}+{alpha}+n+n and {alpha}+t+t cluster structures in the excited states of {sup 10}Be has been discussed. In the previous analysis, all the low-lying states of {sup 10}Be were found to be well described by the motion of the two valence neutrons around two {alpha} clusters. However, the {alpha}+t+t cluster structure was found to coexist with the {alpha}+{alpha}+n+n structure around E{sub x}=15 MeV, close to the corresponding threshold. We have introduced a microscopic model to solve the coupling effect between these two configurations. The K=0 and K=1 states are generated from the {alpha}+t+t configurations due to the spin coupling of two triton clusters. The present case of {sup 10}Be is one of the few examples in which completely different configurations of triton-type ({alpha}+t+t three-center) and {alpha}-type ({alpha}+{alpha}+n+n two-center) clusters coexist in a single nucleus in the same energy region.

  18. What Causes Alpha-1 Antitrypsin Deficiency?

    MedlinePlus

    ... Causes Alpha-1 Antitrypsin Deficiency? Alpha-1 antitrypsin (AAT) deficiency is an inherited disease. "Inherited" means it's ... parents to children through genes. Children who have AAT deficiency inherit two faulty AAT genes, one from ...

  19. How Is Alpha-1 Antitrypsin Deficiency Treated?

    MedlinePlus

    ... Alpha-1 Antitrypsin Deficiency Treated? Alpha-1 antitrypsin (AAT) deficiency has no cure, but its related lung ... pulmonary disease). If you have symptoms related to AAT deficiency, your doctor may recommend: Medicines called inhaled ...

  20. How Is Alpha-1 Antitrypsin Deficiency Diagnosed?

    MedlinePlus

    ... Alpha-1 Antitrypsin Deficiency Diagnosed? Alpha-1 antitrypsin (AAT) deficiency usually is diagnosed after you develop a ... related to the condition. Your doctor may suspect AAT deficiency if you have signs or symptoms of ...

  1. Genetics Home Reference: alpha-mannosidosis

    MedlinePlus

    ... H, Evjen G, Nilssen Ø, Tollersrud OK. Intracellular transport of human lysosomal alpha-mannosidase and alpha-mannosidosis- ... Reviewed : May 2014 Published : May 25, 2016 The resources on this site should not be used as ...

  2. Q (Alpha) Function and Squeezing Effect

    NASA Technical Reports Server (NTRS)

    Yunjie, Xia; Xianghe, Kong; Kezhu, Yan; Wanping, Chen

    1996-01-01

    The relation of squeezing and Q(alpha) function is discussed in this paper. By means of Q function, the squeezing of field with gaussian Q(alpha) function or negative P(a)function is also discussed in detail.

  3. Association of actin with alpha crystallins

    NASA Technical Reports Server (NTRS)

    Gopalakrishnan, S.; Boyle, D.; Takemoto, L.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    The alpha crystallins are cytosolic proteins that co-localize and co-purify with actin-containing microfilaments. Affinity column chromatography employing both covalently-coupled actin or alpha crystallin was used to demonstrate specific and saturable binding of actin with alpha crystallin. This conclusion was confirmed by direct visualization of alpha aggregates bound to actin polymerized in vitro. The significance of this interaction in relation to the functional properties of these two polypeptides will be discussed.

  4. Evaluation of internal alpha-particle radiation exposure and subsequent fertility among a cohort of women formerly employed in the radium dial industry

    SciTech Connect

    Schieve, L.A.; Davis, F.; Freels, S.

    1997-02-01

    This study examined the effect of internal exposure to {alpha}-particle radiation on subsequent fertility among women employed in radium dial industry prior to 1930, when appreciable amounts of radium were often ingested through the practice of pointing the paint brush with the lips. The analysis was limited to women for whom a radium body burden measurement had been obtained and who were married prior to age 45 (n = 603). Internal radiation dose to the ovary was calculated based on initial intakes of radium-226 and radium-228, average ovarian mass, number and energy of {alpha} particles emitted, fraction of energy absorbed within the ovary, effective retention integrals and estimated photon irradiation. Time between marriage and pregnancy, number of pregnancies and number of live births served as surrogates for fertility. Radiation appeared to have no effect on fertility at estimated cumulative ovarian dose equivalents below 5 Sv; above this dose, however, statistically significant declines in both number of pregnancies and live births were observed. These trends persisted after multivariable adjustment for potential confounding variables and after exclusion of subjects contributing a potential classification or selection bias to the study. Additionally, the high-dose group experienced fewer live births than would have been expected based on population rates. There were no differences in time to first pregnancy between high- and low-dose groups. These results are consistent with earlier studies of {gamma}-ray exposures and suggest that exposure to high doses of radiation from internally deposited radium reduces fertility rather than inducing sterility. 42 refs., 5 tabs.

  5. Evaluation of internal alpha radiation exposure and subsequent infertility among a cohort of women formerly employed in the radium dial industry.

    SciTech Connect

    Schieve, L. A.; Davis, F.; Roeske, J.; Handler, A.; Freels, S.; Stinchcomb, T.; Keane, A.; Environmental Research; Univ. of Illinois at Chicago; Univ. of Chicago; DePaul Univ.

    1997-02-01

    This study examined the effect of internal exposure to {alpha}-particle radiation on subsequent fertility among women employed in the radium dial industry prior to 1930, when appreciable amounts of radium were often ingested through the practice of pointing the paint brush with the lips. The analysis was limited to women for whom a radium body burden measurement had been obtained and who were married prior to age 45 (n=603). Internal radiation dose to the ovary was calculated based on initial intakes of radium-226 and radium-228, average ovarian mass, number and energy of {alpha} particles emitted, fraction of energy absorbed with in the ovary, effective retention integrals and estimated photon irradiation. Time between marriage and pregnancy, number of pregnancies and number of live births served as surrogates for fertility. Radiation appeared to have no effect on fertility at estimated cumulative ovarian dose equivalents below 5 Sv; above this dose, however, statistically significant declines in both number of pregnancies and live births were observed. These trends persisted after multivariable adjustment for potential confounding variables and after exclusion of subjects contributing a potential classification or selection bias to the study. Additionally, the high-dose group experienced fewer live births than would have been expected based on population rates. There were no differences in time to first pregnancy between high- and low-dose groups. These results are consistent with earlier studies of {gamma}-ray exposures and suggest that exposure to high doses of radiation from internally deposited radium reduces fertility rather than inducing sterility.

  6. The ultraviolet spectra of Alpha Aquilae and Alpha Canis Minoris

    NASA Technical Reports Server (NTRS)

    Morton, D. C.; Bruzual A., G.; Kurucz, R. L.; Spinrad, H.

    1977-01-01

    Scans of Alpha Aql (A7 IV, V) and Alpha CMi (F5 IV-V) obtained with the Copernicus satellite spectrometer over the wavelength range from 2100 to 3200 A are presented along with a spectrum of the integrated solar disk over the same range procured during a calibrated rocket flight. About 1500 fairly strong absorption lines in the Alpha CMi spectrum between 2400 and 2961 A are identified by comparison with a solar atlas and by using a theoretical spectrum synthesized from a blanketed LTE model with an effective temperature of 6500 K and a surface gravity of 10,000 cm/sec per sec. The Mg II resonance doublet at 2795.528 and 2802.704 A is found to be present in all three stars together with a discontinuity at 2635 A due to Fe II, Fe I, Cr I, and Mn II. It is concluded that the Mg II resonance lines and the 2635-A continuum break would be the best spectral features for estimating the redshift of a galaxy observed at low resolution provided the redshift is not less than about 0.75.

  7. Effectiveness of Alpha Biofeedback Therapy: Negative Results.

    ERIC Educational Resources Information Center

    Watson, Charles G.; Herder, Joseph

    1980-01-01

    Assessed the utility of alpha biofeedback training in the treatment of patients (N=66). Biofeedback and placebo biofeedback groups were given alpha or mock-alpha training sessions. Improvement on 54 variables was compared to that of no-treatment controls. Only a chance number of significant changes appeared among the groups. (Author)

  8. Recent Results on the CKM Angle Alpha

    SciTech Connect

    Mihalyi, A.; /Wisconsin U., Madison

    2005-10-18

    The method to measure the CKM angle {alpha} and the modes sensitive to it are discussed. It is shown that the B {yields} {rho}{rho} decays provide the most stringent constraint on {alpha}, which is found to be {alpha} = 96{sup o} {+-} 10{sup o}(stat) {+-} 4{sup o}(syst){+-} 13{sup o}(penguin).

  9. CONTRIBUTIONS OF TERMINAL PEPTIDES TO THE ASSOCIATIVE BEHAVIOR OF ALPHA-S1 CASEIN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The N- and C-terminal segments of bovine alpha-s1 casein-B (f1-23 and f136-196) were characterized under conditions that promoted or inhibited self-association to determine the relative contributions of each fragment to the interaction of alpha-s1 casein with itself or with other caseins. In earlie...

  10. Alpha voltaic batteries and methods thereof

    NASA Technical Reports Server (NTRS)

    Raffaelle, Ryne P. (Inventor); Jenkins, Phillip (Inventor); Wilt, David (Inventor); Scheiman, David (Inventor); Chubb, Donald (Inventor); Castro, Stephanie (Inventor)

    2011-01-01

    An alpha voltaic battery includes at least one layer of a semiconductor material comprising at least one p/n junction, at least one absorption and conversion layer on the at least one layer of semiconductor layer, and at least one alpha particle emitter. The absorption and conversion layer prevents at least a portion of alpha particles from the alpha particle emitter from damaging the p/n junction in the layer of semiconductor material. The absorption and conversion layer also converts at least a portion of energy from the alpha particles into electron-hole pairs for collection by the one p/n junction in the layer of semiconductor material.

  11. Innovations in Los Alamos alpha box design

    SciTech Connect

    Ledbetter, J.M.; Dowler, K.E.; Cook, J.H.

    1985-01-01

    Destructive examinations of irradiated fuel pins containing plutonium fuel must be performed in shielded hot cells with strict provisions for containing the plutonium. Alpha boxes provide containment for the plutonium, toxic fission products, and other hazardous highly radioactive materials. The alpha box contains windows for viewing and a variety of transfer systems specially designed to allow transfers in and out of the alpha box without spread of the hazardous materials that are contained in the box. Alpha boxes have been in use in the Wing 9 hot cells at Los Alamos National Laboratory for more than 20 years. Features of the newly designed alpha boxes are presented.

  12. Alpha channeling in a rotating plasma.

    PubMed

    Fetterman, Abraham J; Fisch, Nathaniel J

    2008-11-14

    The wave-particle alpha-channeling effect is generalized to include rotating plasma. Specifically, radio frequency waves can resonate with alpha particles in a mirror machine with ExB rotation to diffuse the alpha particles along constrained paths in phase space. Of major interest is that the alpha-particle energy, in addition to amplifying the rf waves, can directly enhance the rotation energy which in turn provides additional plasma confinement in centrifugal fusion reactors. An ancillary benefit is the rapid removal of alpha particles, which increases the fusion reactivity. PMID:19113347

  13. Alpha-1 antitrypsin deficiency, a corporate perspective.

    PubMed

    Stern, Lawrence D

    2013-03-01

    Best-in-class systems have evolved among alpha-1 antitrypsin (AAT) producers, specialty pharmacies and the Alpha-1 Foundation and AlphaNet patient groups. The Genetic Alliance, NORD and other independent parties have recognized the benefits regarding public policy, patient advocacy, medical research, medication adherence, patient identification and health outcomes. Driving the next quantum leap in disease state management for Alpha-1 patients will require strong leadership from both industry and patient groups. Six initiatives are suggested that will sustain best-in-class approaches to identify, treat and even cure Alpha-1 patients. PMID:23527855

  14. A correlation between Hydrogen Alpha-extinction-excess and Hydrogen Alpha surface brightness

    NASA Astrophysics Data System (ADS)

    Xu, Cong

    In the procedure of extinction correction for a hydrogen alpha map of the Large Magellanic Cloud (LMC) (Xu et al. 1992), we found a significant correlation between the hydrogen alpha-extinction-excess E(AH alpha)), defined by the difference between the measured extinction and the extinction estimated from the column density of neutral atomic and molecular gas, and the hydrogen alpha surface brightness B(sub(H alpha)).

  15. Collagen type IV, laminin, alpha-smooth muscle actin (alphaSMA), alpha1 and alpha6 integrins expression in the liver with metastases from malignant gastrointestinal tumours.

    PubMed

    Gulubova, Maya Vladova

    2004-01-01

    Basement membrane proteins and integrins can profoundly affect the biological behaviour of metastasic tumour cells. Using light and ultrastructural immunohistochemistry, we showed the presence of alterations in the occurrence of collagen type IV and laminin, and the expression of alpha1 and alpha6 integrin chains in the livers of patients with metastases from gastric, colorectal and pancreatic cancers. The myofibroblast-like cells in the metastatic stroma were studied. Parallel expressions of alpha-SMA, collagen type IV and alpha1 integrin chain, and appearance of laminin and alpha6 integrin chain immunoreactivity in the extratumoral liver tissue were markedly increased in sinusoids associated with metastases. Furthermore, ultrastructural immunohistochemistry detected tumour cells adhered to amorphous laminin deposits in the metastases. Laminin occurrence in liver sinusoids was visible as fine amorphous deposits in the space of Disse. The similarity between alpha-SMA-positive stromal cells in metastatic stroma and hepatic stellate cells (HSCs) was established by the presence of lipid droplets in their cytoplasm. The immune deposits of alpha1 and alpha6 integrin chains were observed on the hepatocyte microvilli and on the membrane of sinusoidal endothelial cells. These findings suggest that metastatic cells produce stimuli that induce HSCs activation and sinusoidal changes. In addition, the enhanced parallel expression of alphaSMA, collagen type IV, laminin and of alpha1 and alpha6 integrin chains in sinusoids associated with metastases, might potentiate the further dissemination of tumour cells in new liver areas. PMID:15679046

  16. alpha-Tocopheryl phosphate – an active lipid mediator?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The vitamin E (alpha-tocopherol, alphaT) derivative, alpha-tocopheryl phosphate (alphaTP), is detectable in small amounts in plasma, tissues, and cultured cells. Studies done in vitro and in vivo suggest that alphaT can become phosphorylated and alphaTP dephosphorylated, suggesting the existence of ...

  17. Resting-state alpha in autism spectrum disorder and alpha associations with thalamic volume.

    PubMed

    Edgar, J Christopher; Heiken, Kory; Chen, Yu-Han; Herrington, John D; Chow, Vivian; Liu, Song; Bloy, Luke; Huang, Mingxiong; Pandey, Juhi; Cannon, Katelyn M; Qasmieh, Saba; Levy, Susan E; Schultz, Robert T; Roberts, Timothy P L

    2015-03-01

    Alpha circuits (8-12 Hz), necessary for basic and complex brain processes, are abnormal in autism spectrum disorder (ASD). The present study obtained estimates of resting-state (RS) alpha activity in children with ASD and examined associations between alpha activity, age, and clinical symptoms. Given that the thalamus modulates cortical RS alpha rhythms, associations between thalamic structure and alpha activity were examined. RS magnetoencephalography was obtained from 47 typically-developing children (TDC) and 41 children with ASD. RS alpha activity was measured using distributed source localization. Left and right thalamic volume measurements were also obtained. In both groups, the strongest alpha activity was observed in Calcarine Sulcus regions. In Calcarine regions, only TDC showed the expected association between age and alpha peak frequency. ASD had more alpha activity than TDC in regions bordering the Central Sulcus as well as parietal association cortices. In ASD, whereas greater left Central Sulcus relative alpha activity was associated with higher Social Responsiveness Scale (SRS) scores, greater Calcarine region relative alpha activity was associated with lower SRS scores. Although thalamic volume group differences were not observed, relationships between thalamic volume and Calcarine alpha power were unique to TDC. The present study also identified a failure to shift peak alpha frequency as a function of age in primary alpha-generating areas in children with ASD. Findings suggested that increased RS alpha activity in primary motor and somatosensory as well as parietal multimodal areas-with increased alpha thought to reflect greater inhibition-might impair the ability to identify or interpret social cues. Finally, to our knowledge, this is the first study to report associations between thalamic volume and alpha power, an association observed only in TDC. The lack of thalamic and alpha associations in ASD suggests thalamic contributions to RS alpha abnormalities in ASD. PMID:25231288

  18. Alpha thalassaemia in Yemeni children with sickle cell disease.

    PubMed

    el-Hazmi, M A; Warsy, A S

    1999-12-01

    Alpha thalassaemia frequently occurs in several of the Middle Eastern populations. This study was conducted on 26 sickle cell disease (SCD) patients from Yemen and 19 normal children (Hb AA) living in Riyadh, Saudi Arabia. Blood samples were extracted by venepuncture, and haematological and biochemical parameters were estimated. DNA was extracted from the buffy coat and analysed for alpha-gene arrangement using Bam HI and Bgl II. The frequency of alpha-gene deletion in the total Yemeni group (26 SCD + 19 Hb AA) was 0.311 for one alpha-gene deletion (-alpha/alpha alpha) and 0.13 for two alpha-gene deletions (-alpha/-alpha). When separated on the basis of the Hb phenotype the alpha-gene deletion frequency was significantly higher (-alpha/alpha alpha = 0.346 and -alpha/-alpha = 0.231) in the SCD patients compared to the normal Hb AA group (-alpha/alpha alpha = 0.263 and -alpha/-alpha = 0). In the Hb AA group one child had triple alpha-gene arrangement (alpha alpha alpha/alpha alpha) giving an overall frequency of triple alpha-gene as 0.022. Haematological parameters showed variations in the SCD patients with and without alpha-gene deletion. This paper shows for the first time that alpha-gene deletion occurs in the Yemenis and the frequency is higher in patients with SCD. Further population-based studies are required to determine the exact frequency of the different types of alpha-thalassaemias in the overall Yemeni population. PMID:10667010

  19. Variation in RBE for Survival of V79-4 Cells as a Function of Alpha-Particle (Helium Ion) Energy.

    PubMed

    Tracy, Bliss L; Stevens, David L; Goodhead, Dudley T; Hill, Mark A

    2015-07-01

    High linear energy transfer (LET) α particles are important with respect to the carcinogenic risk associated with human exposure to ionizing radiation, most notably to radon and its progeny. Additionally, the potential use of alpha-particle-emitting radionuclides in radiotherapy is increasingly being explored. Within the body the emitted alpha particles slow down, traversing a number of cells with a range of energies and therefore with varying efficiencies at inducing biological response. The LET of the particle typically rises from between ~70-90 keV μm(-1) at the start of the track (depending on initial energy) to a peak of ~237 keV μm(-1) towards the end of the track, before falling again at the very end of its range. To investigate the variation in biological response with incident energy, a plutonium-238 alpha-particle irradiator was calibrated to enable studies with incident energies ranging from 4.0 MeV down to 1.1 MeV. The variation in clonogenic survival of V79-4 cells was determined as a function of incident energy, along with the relative variation in the initial yields of DNA double-strand breaks (DSB) measured using the FAR assay. The clonogenic survival data also extends previously published data obtained at the Medical Research Council (MRC), Harwell using the same cells irradiated with helium ions, with energies ranging from 34.9 MeV to 5.85 MeV. These studies were performed in conjunction with cell morphology measurements on live cells enabling the determination of absorbed dose and calculation of the average LET in the cell. The results show an increase in relative biological effectiveness (RBE) for cell inactivation with decreasing helium ion energy (increasing LET), reaching a maximum for incident energies of ~3.2 MeV and corresponding average LET of 131 keV μm(-1), above which the RBE is observed to fall at lower energies (higher LETs). The effectiveness of single alpha-particle traversals (relevant to low-dose exposure) at inducing cell inactivation was observed to increase with decreasing energy to a peak of ~68% survival probability for incident energies of ~1.8 MeV (average LET of 190 keV μm(-1)) producing ~0.39 lethal lesions per track. However, the efficiency of a single traversal will also vary significantly with cell morphology and angle of incidence, as well as cell type. PMID:26121227

  20. High gas flow alpha detector

    DOEpatents

    Bolton, R.D.; Bounds, J.A.; Rawool-Sullivan, M.W.

    1996-05-07

    An alpha detector for application in areas of high velocity gas flows, such as smokestacks and air vents. A plurality of spaced apart signal collectors are placed inside an enclosure, which would include smokestacks and air vents, in sufficient numbers to substantially span said enclosure so that gas ions generated within the gas flow are electrostatically captured by the signal collector means. Electrometer means and a voltage source are connected to the signal collectors to generate an electrical field between adjacent signal collectors, and to indicate a current produced through collection of the gas ions by the signal collectors. 4 figs.

  1. Targeted alpha therapy for cancer

    NASA Astrophysics Data System (ADS)

    Allen, Barry J.; Raja, Chand; Rizvi, Syed; Li, Yong; Tsui, Wendy; Zhang, David; Song, Emma; Qu, Chang Fa; Kearsley, John; Graham, Peter; Thompson, John

    2004-08-01

    Targeted alpha therapy (TAT) offers the potential to inhibit the growth of micrometastases by selectively killing isolated and preangiogenic clusters of cancer cells. The practicality and efficacy of TAT is tested by in vitro and in vivo studies in melanoma, leukaemia, colorectal, breast and prostate cancers, and by a phase 1 trial of intralesional TAT for melanoma. The alpha-emitting radioisotope used is Bi-213, which is eluted from the Ac-225 generator and chelated to a cancer specific monoclonal antibody (mab) or protein (e.g. plasminogen activator inhibitor-2 PAI2) to form the alpha-conjugate (AC). Stable alpha-ACs have been produced which have been tested for specificity and cytotoxicity in vitro against melanoma (9.2.27 mab), leukaemia (WM60), colorectal (C30.6), breast (PAI2, herceptin), ovarian (PAI2, herceptin, C595), prostate (PAI2, J591) and pancreatic (PAI2, C595) cancers. Subcutaneous inoculation of 1-1.5 million human cancer cells into the flanks of nude mice causes tumours to grow in all mice. Tumour growth is compared for untreated controls, nonspecific AC and specific AC, for local (subcutaneous) and systemic (tail vein or intraperitoneal) injection models. The 213Bi-9.2.27 AC is injected into secondary skin melanomas in stage 4 patients in a dose escalation study to determine the effective tolerance dose, and to measure kinematics to obtain the equivalent dose to organs. In vitro studies show that TAT is one to two orders of magnitude more cytotoxic to targeted cells than non-specific ACs, specific beta emitting conjugates or free isotopes. In vivo local TAT at 2 days post-inoculation completely prevents tumour formation for all cancers tested so far. Intra-lesional TAT can completely regress advanced sc melanoma but is less successful for breast and prostate cancers. Systemic TAT inhibits the growth of sc melanoma xenografts and gives almost complete control of breast and prostate cancer tumour growth. Intralesional doses up to 450 µCi in human patients are effective in regressing melanomas, with no concomitant complications. These results point to the application of local and systemic TAT in the management of secondary cancer. Results of the phase 1 clinical trial of TAT of subcutaneous, secondary melanoma indicate proof of the principle that TAT can make tumours in patients regress.

  2. Autocrine regulation of osteoclast formation and bone resorption by IL-1 alpha and TNF alpha.

    PubMed

    Tani-Ishii, N; Tsunoda, A; Teranaka, T; Umemoto, T

    1999-10-01

    Bone resorption is regulated by the cytokines within marrow cells that mediate osteoclast formation and activation. IL-1 and TNF induce bone resorption by stimulating the production of osteoclast-like multinucleated cells and by increasing the bone-resorbing activity of formed osteoclasts. This study was designed to detect IL-1 and TNF in osteoclasts in vitro and to determine whether these cytokines up-regulate osteoclast differentiation and bone resorption. The production of IL-1 alpha, -beta, and TNF alpha, beta in osteoclasts was examined immunohistochemically and by in situ hybridization. In the co-culture of C57BL/6N mouse bone marrow and MC3T3-G2/PA6 cells, a colony of osteoclasts formed, and IL-1 alpha and TNF alpha were detected. However, IL-1 beta and TNF beta were not detected. To investigate the role of IL-1 alpha and TNF alpha from osteoclasts, we enumerated TRAP-positive cells and measured the resorption pit areas in the presence of antibodies against IL-1 alpha and TNF alpha. The addition of antibodies against IL-1 alpha and TNF alpha to the co-culture system decreased the number of TRAP-positive colonies at seven days after incubation (anti-IL-1 alpha, 25.0 +/- 2.3%; anti-TNF alpha, 41.7 +/- 3.7%; anti-IL-1 alpha + anti-TNF alpha, 40.5 +/- 1.3%; and control, 100%), and the ratio of mononuclear to multinuclear cells had changed (anti-IL-1 alpha, 90:10; anti-TNF alpha, 75:25; anti-IL-1 alpha+ anti-TNF alpha, 88:12; and control, 60:40). The total pit areas per dentin slice also decreased with the addition of antibodies (anti-IL-1 alpha, 28,828; anti-TNF alpha, 49,249; anti-IL-1 alpha + anti-TNF alpha, 30,685; and control, 303,139 mm2). These results suggest that local production of IL-1 alpha and TNF alpha by osteoclasts is an important mechanism for regulating the osteoclast differentiation and bone resorptive process. PMID:10520966

  3. In Vitro Cytotoxicity of Low-Dose-Rate Radioimmunotherapy by the Alpha-Emitting Radioimmunoconjugate Thorium-227-DOTA-Rituximab

    SciTech Connect

    Dahle, Jostein; Krogh, Cecilie; Melhus, Katrine B.; Borrebaek, Jorgen; Larsen, Roy H.; Kvinnsland, Yngve

    2009-11-01

    Purpose: To determine whether the low-dose-rate alpha-particle-emitting radioimmunoconjugate {sup 227}Th-1,4,7,10-p-isothiocyanato-benzyl-tetraazacyclododecane-1,4,7, 10-tetraacetic acid (DOTA)-rituximab can be used to inactivate lymphoma cells growing as single cells and small colonies. Methods and Materials: CD20-positive lymphoma cell lines were treated with {sup 227}Th-DOTA-rituximab for 1-5 weeks. To simulate the in vivo situation with continuous but decreasing supply of radioimmunoconjugates from the blood pool, the cells were not washed after incubation with {sup 227}Th-DOTA-rituximab, but half of the medium was replaced with fresh medium, and cell concentration and cell-bound activity were determined every other day after start of incubation. A microdosimetric model was established to estimate the average number of hits in the nucleus for different localizations of activity. Results: There was a specific targeted effect on cell growth of the {sup 227}Th-DOTA-rituximab treatment. Although the cells were not washed after incubation with {sup 227}Th-DOTA-rituximab, the average contribution of activity in the medium to the mean dose was only 6%, whereas the average contribution from activity on the cells' own surface was 78%. The mean dose rates after incubation with 800 Bq/mL {sup 227}Th-DOTA-rituximab varied from 0.01 to 0.03 cGy/min. The average delay in growing from 10{sup 5} to 10{sup 7} cells/mL was 15 days when the cells were treated with a mean absorbed radiation dose of 2 Gy alpha-particle radiation from {sup 227}Th-DOTA-rituximab, whereas it was 11 days when the cells were irradiated with 6 Gy of X-radiation. The relative biologic effect of the treatment was estimated to be 2.9-3.4. Conclusions: The low-dose-rate radioimmunoconjugate {sup 227}Th-DOTA-rituximab is suitable for inactivation of single lymphoma cells and small colonies of lymphoma cells.

  4. Selective sorting of alpha-granule proteins

    PubMed Central

    Italiano, J.E.; Battinelli, E. M.

    2010-01-01

    Summary One of the main functions of blood platelets is to secrete a variety of substances that can modify a developing thrombus, regulate the growth of the vasculature, promote wound repair, and contribute to cell-adhesive events. The majority of this vast array of secreted proteins is stored in alpha-granules. Until recently, it was assumed that platelets contained one homogeneous population of alpha-granules that undergo complete de-granulation during platelet activation. This review focuses on the mechanisms of alpha-granule biogenesis and secretion, with a particular emphasis on recent findings that clearly demonstrate that platelets contain distinct subpopulations of alpha-granules that undergo differential release during activation. We consider the implications of this new paradigm of platelet secretion, discuss mechanisms of alpha-granule biogenesis, and review the molecular basis of transport and delivery of alpha-granules to assembling platelets. PMID:19630794

  5. Microtubule depolymerization potentiates alpha-synuclein oligomerization.

    PubMed

    Esteves, A Raquel; Arduíno, Daniela M; Swerdlow, Russell H; Oliveira, Catarina R; Cardoso, Sandra M

    2010-01-01

    Parkinson's disease (PD) is associated with perturbed mitochondria function and alpha-synuclein fibrillization. We evaluated potential mechanistic links between mitochondrial dysfunction and alpha-synuclein aggregation. We studied a PD cytoplasmic hybrid (cybrid) cell line in which platelet mitochondria from a PD subject were transferred to NT2 neuronal cells previously depleted of endogenous mitochondrial DNA. Compared to a control cybrid cell line, the PD line showed reduced ATP levels, an increased free/polymerized tubulin ratio, and alpha-synuclein oligomer accumulation. Taxol (which stabilizes microtubules) normalized the PD tubulin ratio and reduced alpha-synuclein oligomerization. A nexus exists between mitochondrial function, cytoskeleton homeostasis, and alpha-synuclein oligomerization. In our model, mitochondrial dysfunction triggers an increased free tubulin, which destabilizes the microtubular network and promotes alpha-synuclein oligomerization. PMID:20552056

  6. Pharmacological effects of ephedrine alkaloids on human alpha(1)- and alpha(2)-adrenergic receptor subtypes.

    PubMed

    Ma, Guoyi; Bavadekar, Supriya A; Davis, Yolande M; Lalchandani, Shilpa G; Nagmani, Rangaswamy; Schaneberg, Brian T; Khan, Ikhlas A; Feller, Dennis R

    2007-07-01

    Ephedra species of plants have both beneficial and adverse effects primarily associated with the presence of ephedrine alkaloids. Few reports have appeared that examine the direct actions of ephedrine alkaloids on human subtypes of adrenergic receptors (ARs). In the present study, ephedrine alkaloids were evaluated for their binding affinities on human alpha(1A)-, alpha(1B)-, alpha(1D)-, alpha(2A)-, alpha(2B)-, and alpha(2C)-AR subtypes expressed in HEK and Chinese hamster ovary cells. Cell-based reporter gene assays were used to establish functional activity of ephedrine alkaloids at alpha(1A)-, alpha(2A)-, and alpha(2C)-ARs. The data showed that ephedrine alkaloids did not activate alpha(1)- and alpha(2)-ARs and that they antagonized the agonist-mediated effects of phenylephrine and medetomidine on alpha(1)- and alpha(2)-ARs, respectively. As in the binding studies, 1R,2R- and 1R,2S-ephedrine showed greater functional antagonist activity than the 1S,2R- and 1S,2S-isomers. The rank order of affinity for the isomers was 1R,2R > 1R,2S > 1S,2R > 1S,2S. The rank order of potencies of alkaloids containing a 1R,2S-configuration was norephedrine > or = ephedrine > N-methylephedrine. These studies have demonstrated that orientation of the beta-hydroxyl group on the ethylamino side chain and the state of N-methyl substitution are important for alpha-AR binding and functional activity of the ephedrine alkaloids. In conclusion, the ephedrine isomers and analogs studied did not exhibit any direct agonist activity and were found to possess moderate antagonist activities on cloned human alpha-ARs. The blockade of presynaptic alpha(2A)- and alpha(2C)-ARs may have a pharmacological role in the direct actions of Ephedra alkaloids. PMID:17405867

  7. High-alpha space trucks

    NASA Astrophysics Data System (ADS)

    Cook, Layne M.; Ball, Jim

    1997-01-01

    Vertically-landing Reusable Launch Vehicles (RLVs) are the best hope of building a true ``Space Truck'' with current technology. Because they do not require a low angle-of-attack (AOA, or alpha) horizontal landing, they can be designed to operate exclusively at very high angles-of-attack. This offers savings in vehicle dry weight and complexity, which can be traded for significantly heavier payload, more ascent velocity, or extra design margin. The price for abandoning low angle-of-attack flight is reduced crossrange. To quantify the potential weight reduction, a trade study was performed to determine the relationship between a vehicle's maximum crossrange (angle-of-attack) and it's dry weight (payload margin). At the study conclusion, three vertically-landing (VL) vehicles provided multiple points on a payload weight vs. maximum crossrange curve, showing significant payload increases as crossrange is sacrificed. This is primarily the result of being able to simplify the structure, fly a cooler entry trajectory, and be aerodynamically stable through the entire flight. This reduces subsystem requirements and complexity, enhancing reliability. Further benefits are realized in reduced landing propellant requirements and simplifying or eliminating the ``rotation'' maneuver. This paper also suggests unique operability solutions that adapt high-alpha vehicles to traditional high-crossrange missions such as the polar ``once-around'' flight, and proposes a small scale drop-test program to prove the subsonic and landing portion of the flight envelope.

  8. A NEW POPULATION OF HIGH-z, DUSTY Ly{alpha} EMITTERS AND BLOBS DISCOVERED BY WISE: FEEDBACK CAUGHT IN THE ACT?

    SciTech Connect

    Bridge, Carrie R.; Blain, Andrew; Borys, Colin J. K.; Griffith, Roger L.; Tsai, Chao-Wei; Petty, Sara; Farrah, Duncan; Benford, Dominic; Eisenhardt, Peter; Stern, Daniel; Wu Jingwen; Jarrett, Tom; Lonsdale, Carol; Stanford, Spencer A.; Wright, Edward L.

    2013-06-01

    By combining data from the NASA Wide-field Infrared Survey Explorer (WISE) mission with optical spectroscopy from the W. M. Keck telescope, we discover a mid-IR color criterion that yields a 78% success rate in identifying rare, typically radio-quiet, 1.6 {approx}< z {approx}< 4.6 dusty Ly{alpha} emitters (LAEs). Of these, at least 37% have emission extended on scales of 30-100 kpc and are considered Ly{alpha} ''blobs'' (LABs). The objects have a surface density of only {approx}0.1 deg{sup -2}, making them rare enough that they have been largely missed in deep, small area surveys. We measured spectroscopic redshifts for 92 of these galaxies, and find that the LAEs (LABs) have a median redshift of 2.3 (2.5). The WISE photometry coupled with data from Herschel (Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA) reveals that these galaxies are in the Hyper Luminous IR galaxy regime (L{sub IR} {approx}> 10{sup 13}-10{sup 14} L{sub Sun }) and have warm colors. They are typically more luminous and warmer than other dusty, z {approx} 2 populations such as submillimeter-selected galaxies and dust-obscured galaxies. These traits are commonly associated with the dust being illuminated by intense active galactic nucleus activity. We hypothesize that the combination of spatially extended Ly{alpha}, large amounts of warm IR-luminous dust, and rarity (implying a short-lived phase) can be explained if the galaxies are undergoing brief, intense ''feedback'' transforming them from an extreme dusty starburst/QSO into a mature galaxy.

  9. A New Population of High-z, Dusty Lyman-alpha Emitters and Blobs Discovered by WISE: Feedback Caught in the Act?

    NASA Technical Reports Server (NTRS)

    Bridge, Carrie R.; Blain, Andrew; Borys, Colin J. K.; Petty, Sara; Benford, Dominic; Eisenhardt, Peter; Farrah, Duncan; Griffith, Roger, L.; Jarrett, Tom; Lonsdale, Carol; Stanford. Spencer A.; Stern, Daniel; Tsai, Chao-Wei; Wright, Edward L.; Wu, Jingwen

    2013-01-01

    By combining data from the NASA Wide-field Infrared Survey Explorer (WISE) mission with optical spectroscopy from the W. M. Keck telescope, we discover a mid-IR color criterion that yields a 78% success rate in identifying rare, typically radio-quiet, 1.6 approx. < z approx. < 4.6 dusty Ly-alpha emitters (LAEs). Of these, at least 37% have emission extended on scales of 30-100 kpc and are considered Ly-alpha "blobs" (LABs). The objects have a surface density of only approx.. 0.1 deg(exp -2), making them rare enough that they have been largely missed in deep, small area surveys. We measured spectroscopic redshifts for 92 of these galaxies, and find that the LAEs (LABs) have a median redshift of 2.3 (2.5). The WISE photometry coupled with data from Herschel (Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA) reveals that these galaxies are in the Hyper Luminous IR galaxy regime (L(sub IR) approx. > 10(exp 13)-10(exp 14) Solar L) and have warm colors. They are typically more luminous and warmer than other dusty, z approx.. 2 populations such as submillimeter-selected galaxies and dust-obscured galaxies. These traits are commonly associated with the dust being illuminated by intense active galactic nucleus activity. We hypothesize that the combination of spatially extended Ly-alpha, large amounts of warm IR-luminous dust, and rarity (implying a short-lived phase) can be explained if the galaxies are undergoing brief, intense "feedback" transforming them from an extreme dusty starburst/QSO into a mature galaxy.

  10. Beta/alpha continuous air monitor

    DOEpatents

    Becker, G.K.; Martz, D.E.

    1988-06-27

    A single deep layer silicon detector in combination with a microcomputer, recording both alpha and beta activity and the energy of each pulse, distinquishing energy peaks using a novel curve fitting technique to reduce the natural alpha counts in the energy region where plutonium and other transuranic alpha emitters are present, and using a novel algorithm to strip out radon daughter contribution to actual beta counts. 7 figs.

  11. Beta/alpha continuous air monitor

    DOEpatents

    Becker, Gregory K.; Martz, Dowell E.

    1989-01-01

    A single deep layer silicon detector in combination with a microcomputer, recording both alpha and beta activity and the energy of each pulse, distinguishing energy peaks using a novel curve fitting technique to reduce the natural alpha counts in the energy region where plutonium and other transuranic alpha emitters are present, and using a novel algorithm to strip out radon daughter contribution to actual beta counts.

  12. Gene transfer mediated by alpha2-macroglobulin.

    PubMed Central

    Schneider, H; Huse, K; Birkenmeier, G; Otto, A; Scholz, G H

    1996-01-01

    alpha2-Macroglobulin covalently linked to poly(L)-lysine can be used as a vehicle for receptor-mediated gene transfer. This modified alpha2-macroglobulin maintains its ability to bind to the alpha2-macroglobulin receptor, and was shown to introduce a luciferase reporter gene plasmid into HepG2 human hepatoma cells in vitro. The alpha2-macroglobulin receptor is a very large and multifunctional cell surface receptor, whose rapid and efficient internalization rate makes it attractive for gene therapy, e.g. for hepatic gene targeting via injection into the portal vein. PMID:8871570

  13. Prospects for alpha particle studies on TFTR

    SciTech Connect

    Zweben, S.J.

    1987-05-01

    TFTR is expected to produce approximately 5 MW of alpha heating during the D/T Q approx. = 1 phase of operation in 1990. At that point the collective confinement properties and the heating effects of alpha particles become accessible for study for the first time. This paper outlines the potential performance of TFTR with respect to alpha particle production, the diagnostics which will be available for alpha particle measurements, and the physics issues which can be studied both before and during D/T operation.

  14. Resting-State Alpha in Autism Spectrum Disorder and Alpha Associations with Thalamic Volume

    ERIC Educational Resources Information Center

    Edgar, J. Christopher; Heiken, Kory; Chen, Yu-Han; Herrington, John D.; Chow, Vivian; Liu, Song; Bloy, Luke; Huang, Mingxiong; Pandey, Juhi; Cannon, Katelyn M.; Qasmieh, Saba; Levy, Susan E.; Schultz, Robert T.; Roberts, Timothy P. L.

    2015-01-01

    Alpha circuits (8-12 Hz), necessary for basic and complex brain processes, are abnormal in autism spectrum disorder (ASD). The present study obtained estimates of resting-state (RS) alpha activity in children with ASD and examined associations between alpha activity, age, and clinical symptoms. Given that the thalamus modulates cortical RS alpha…

  15. Solution conformation of a neuronal nicotinic acetylcholine receptor antagonist {alpha}-conotoxin OmIA that discriminates {alpha}3 vs. {alpha}6 nAChR subtypes

    SciTech Connect

    Chi, Seung-Wook; Kim, Do-Hyoung; Olivera, Baldomero M.; McIntosh, J. Michael; Han, Kyou-Hoon . E-mail: khhan600@kribb.re.kr

    2006-06-23

    {alpha}-Conotoxin OmIA from Conus omaria is the only {alpha}-conotoxin that shows a {approx}20-fold higher affinity to the {alpha}3{beta}2 over the {alpha}6{beta}2 subtype of nicotinic acetylcholine receptor. We have determined a three-dimensional structure of {alpha}-conotoxin OmIA by nuclear magnetic resonance spectroscopy. {alpha}-Conotoxin OmIA has an '{omega}-shaped' overall topology with His{sup 5}-Asn{sup 12} forming an {alpha}-helix. Structural features of {alpha}-conotoxin OmIA responsible for its selectivity are suggested by comparing its surface characteristics with other functionally related {alpha}4/7 subfamily conotoxins. Reduced size of the hydrophilic area in {alpha}-conotoxin OmIA seems to be associated with the reduced affinity towards the {alpha}6{beta}2 nAChR subtype.

  16. Psychiatric Symptoms in Alpha-Mannosidosis

    ERIC Educational Resources Information Center

    Malm, D.; Pantel, J.; Linaker, O. M.

    2005-01-01

    Alpha-mannosidosis is characterized by mild to moderate intellectual disability (ID), moderate to severe neurosensory hearing loss, frequent infections, psychomotor disturbances and skeletal dysmorphism. For the first time, a panel of nine alpha-mannosidosis patients with psychiatric symptoms is presented. The clinical picture has several…

  17. Elementary Processes Underlying Alpha Channeling in Tokamaks

    SciTech Connect

    NM.J. Fisch

    2012-06-15

    Alpha channeling in tokamaks is speculative, but also extraordinarily attractive. Waves that can accomplish this effect have been identified. Key aspects of the theory now enjoy experimental confirmation. This paper will review the elementary processes of wave-particle interactions in plasma that underlie the alpha channeling effect

  18. Typical uncertainties in alpha-particle spectrometry

    NASA Astrophysics Data System (ADS)

    Pommé, S.

    2015-06-01

    Alpha-particle spectrometry is routinely performed with the aim of measuring absolute activities, activity ratios between different alpha-emitting nuclides or decay data such as branching factors, alpha emission probabilities and relative half-lives. It is most commonly performed with ion-implanted silicon detectors. Strong features of the technique are the low background levels that can be achieved due to low sensitivity to other types of radiation, the intrinsic efficiency close to 1 which reduces the efficiency calculations to a geometrical problem and the uniqueness of the energy spectra for each α-decaying nuclide. The main challenge is the limitation to the attainable energy resolution, even with thin and homogenous sources, which causes alpha energy peaks to be partially unresolved due to their width and low-energy tailing. The spectral deconvolution often requires fitting of analytical functions to each peak in the alpha spectrum. True coincidence effects between alpha particles and subsequently emitted conversion electrons cause distortions of the alpha spectra which lead to significant changes in the apparent peak area ratios. Optimum energy resolution can only be achieved on very thin sources, which puts constraints on the source preparation techniques. Radiochemical separations may be needed to extract the alpha emitters from voluminous matrices and efficiency tracing is performed by adding in another isotope by known amounts. Typical uncertainty components are discussed by means of some hypothetical examples.

  19. Meta-Analysis of Coefficient Alpha

    ERIC Educational Resources Information Center

    Rodriguez, Michael C.; Maeda, Yukiko

    2006-01-01

    The meta-analysis of coefficient alpha across many studies is becoming more common in psychology by a methodology labeled reliability generalization. Existing reliability generalization studies have not used the sampling distribution of coefficient alpha for precision weighting and other common meta-analytic procedures. A framework is provided for…

  20. Coefficient Alpha Bootstrap Confidence Interval under Nonnormality

    ERIC Educational Resources Information Center

    Padilla, Miguel A.; Divers, Jasmin; Newton, Matthew

    2012-01-01

    Three different bootstrap methods for estimating confidence intervals (CIs) for coefficient alpha were investigated. In addition, the bootstrap methods were compared with the most promising coefficient alpha CI estimation methods reported in the literature. The CI methods were assessed through a Monte Carlo simulation utilizing conditions…

  1. Determination of the Strong Coupling Alpha

    NASA Astrophysics Data System (ADS)

    Li, Yuekuan

    An experimental determination of the strong coupling alpha_{s}, and Lambda_{overline{MS }}, the fundamental scale parameter of QCD, have been extracted from the differential jet rates of multi-hadronic final states in e^+e^ - annihilations using the AMY detector at TRISTAN. The theoretical predictions from Next-to-Leading-Logarithm (NLL) Parton-Shower QCD calculations are compared to the data. The use of NLL allows one to fix the QCD scale parameter, which significantly reduces the systematic effects associated with the choice of a renormalization scale. The precision of previous extractions of alpha_ {s} based on second-order Matrix Element calculations have been severely limited by renormalization scale uncertainties. Using a NLL calculation we obtain alpha_{s}(M _{rm Z}) = 0.119 +/- 0.006 (total error) and its corresponding Lambda{(5)over MS} is 240 +/- _sp{65 }{80} MeV (total error). Systematic errors due to fragmentation and jet-clustering schemes are discussed. Comparisons are made to values of alpha_{s} derived from other measurements, and the running nature of the strong coupling is demonstrated at different energies by the energy dependence of alpha_{s}.

  2. 27 CFR 21.95 - Alpha terpineol.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Alpha terpineol. 21.95 Section 21.95 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Alpha terpineol. (a) Boiling point at 752mm 218.8-219.4 °C. (b) Density at 15° 0.9386. (c)...

  3. Commentary on Coefficient Alpha: A Cautionary Tale

    ERIC Educational Resources Information Center

    Green, Samuel B.; Yang, Yanyun

    2009-01-01

    The general use of coefficient alpha to assess reliability should be discouraged on a number of grounds. The assumptions underlying coefficient alpha are unlikely to hold in practice, and violation of these assumptions can result in nontrivial negative or positive bias. Structural equation modeling was discussed as an informative process both to…

  4. Atypical Alpha Asymmetry in Adults with ADHD

    ERIC Educational Resources Information Center

    Hale, T. Sigi; Smalley, Susan L.; Hanada, Grant; Macion, James; McCracken, James T.; McGough, James J.; Loo, Sandra K.

    2009-01-01

    Introduction: A growing body of literature suggests atypical cerebral asymmetry and interhemispheric interaction in ADHD. A common means of assessing lateralized brain function in clinical populations has been to examine the relative proportion of EEG alpha activity (8-12 Hz) in each hemisphere (i.e., alpha asymmetry). Increased rightward alpha…

  5. Teaching Calculus with Wolfram|Alpha

    ERIC Educational Resources Information Center

    Dimiceli, Vincent E.; Lang, Andrew S. I. D.; Locke, LeighAnne

    2010-01-01

    This article describes the benefits and drawbacks of using Wolfram|Alpha as the platform for teaching calculus concepts in the lab setting. It is a result of our experiences designing and creating an entirely new set of labs using Wolfram|Alpha. We present the reasoning behind our transition from using a standard computer algebra system (CAS) to…

  6. 27 CFR 21.95 - Alpha terpineol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Alpha terpineol. 21.95 Section 21.95 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Alpha terpineol. (a) Boiling point at 752mm 218.8-219.4 °C. (b) Density at 15° 0.9386. (c)...

  7. Teaching Calculus with Wolfram|Alpha

    ERIC Educational Resources Information Center

    Dimiceli, Vincent E.; Lang, Andrew S. I. D.; Locke, LeighAnne

    2010-01-01

    This article describes the benefits and drawbacks of using Wolfram|Alpha as the platform for teaching calculus concepts in the lab setting. It is a result of our experiences designing and creating an entirely new set of labs using Wolfram|Alpha. We present the reasoning behind our transition from using a standard computer algebra system (CAS) to

  8. Measurement of alpha particles on PLT

    SciTech Connect

    Murphy, T.J.; Strachan, J.D.

    1984-12-01

    The radial emission profile of the d(/sup 3/He,p)..cap alpha.. fusion reaction was measured on PLT by pitch angle resolution of the escaping 3.7-MeV alphas. The d-/sup 3/He reactions were produced by /sup 3/He minority ICRF and the emission was strongly peaked at the ICRF resonance layer.

  9. 27 CFR 21.95 - Alpha terpineol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Alpha terpineol. 21.95 Section 21.95 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants 21.95 Alpha terpineol. (a) Boiling point at...

  10. Microbial transformations of alpha-santonin.

    PubMed

    Ata, Athar; Nachtigall, Jason A

    2004-01-01

    Fungal biotransformations of alpha-santonin (1) were conducted with Mucor plumbeus (ATCC 4740), Cunninghamella bainieri (ATCC 9244), Cunninghamella echinulata (ATCC 9245), Curvularia lunata (ATCC 12017) and Rhizopus stolonifer (ATCC 10404). Rhizopus stolonifer (ATCC 10404) metabolized compound 1 to afford 3,4-epoxy-alpha-santonin (2) and 4,5-dihydro-alpha-santonin (3) while Cunninghamella bainieri (ATCC 9244), Cunninghamella echinulata (ATCC 9245) and Mucor plumbeus (ATCC 4740) were capable of metabolizing compound 1 to give a reported metabolite, 1,2-dihydro-alpha-santonin (4). The structures of these transformed metabolites were established with the aid of extensive spectroscopic studies. These fungi regiospecifically reduced the carbon-carbon double bond in ring A of alpha-santonin. PMID:15241928

  11. The isotropic condition of energetic particles emitted from a large solar flare. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Spalding, J.

    1983-01-01

    Isotope abundance ratios for 5 to 50 MeV/nuc nuclei from a large solar flare were measured. The measurements were made by the heavy isotope spectrometer telescope (HIST) on the ISEE-3 satellite orbiting the Sun near an Earth-Sun liberation point approximately one million miles sunward of the Earth. Finite values for the isotope abundance ratios C-13/C-12, N-15/N-14, O-18/O-16, Ne-22/Ne-20, Mg-25/Mg-24, and Mg-26/Mg-24, and upper limits for the isotope abundance ratios He-3/He-4, C-14/C-12, O-17/O-16 and Ne-21/Ne-20 were reported. Element abundances and spectra were measured to compare the flare with other reported flares. The flare is a typical large flare with low Fe/O abundance or = to 0.1). For C-13/C-12, N-15/N-14, O-18/O-16, Mg-25/Mg-24 and Mg-26/Mg-24 isotope abundance ratios agree with the solar system abundance ratios. Measurement for Ne-22/Ne-20 agree with the isotopic composition of the meteoritic component neon-A.

  12. Toxicity of particles emitted from combustion of waste crankcase oil: in vitro and in vivo studies.

    PubMed

    Mumford, J L; Hatch, G E; Hall, R E; Jackson, M A; Merrill, R G; Lewtas, J

    1986-07-01

    The ever-rising cost of energy provides incentives for the utilization of low-cost waste crankcase oil (WCO) for space heating. Although WCO is known to contain toxic heavy metals, the potential health hazards of emissions and waste products resulting from the combustion of WCO are unknown. Thus, the toxicity of the emission particles and waste products from two different types of burners, a Dravo atomizing oil burner (AOB) and a Kroll vaporizing oil burner (VOB), is evaluated using automotive WCO. Samples are characterized by performing elemental analysis and scanning electron microscopy. Both burners emitted fine (less than or equal to 3 microns), respirable particles. The AOB emission particles contained high concentrations of toxic heavy metals, especially Pb, which showed concentrations as high as 7.5%. The VOB retained a significant amount of heavy metals in the burner residue and emitted a much smaller quantity into the air. The toxicity of AOB emission particles, VOB emission particles, and VOB waste residue is evaluated in three bioassay systems, including a rabbit alveolar macrophage (RAM) cytotoxicity in vitro assay, an intratracheal injection infectivity assay, and a peritoneal irritancy test in mice. The emission particles from both burners and leachate from VOB residue produce a dose-related reduction in viability and cellular adenosine triphosphate (ATP) in alveolar macrophages following 20-hr exposure. Acidity of the RAM medium due to the presence of VOB emission particles and waste leachate contributes to its toxicity.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3732672

  13. TOXICITY OF PARTICLES EMITTED FROM COMBUSTION OF WASTE CRANKCASE OIL: IN VITRO AND IN VIVO STUDIES

    EPA Science Inventory

    The ever-rising cost of energy provides incentives for the utilization of waste crankcase oil (WCO) for space heating. The potential health hazards of emissions and waste products resulting from the combustion of WCO are unknown. The toxicity of the emission particles and waste p...

  14. Characterization and control of airborne particles emitted during production of epoxy/carbon nanotube nanocomposites.

    PubMed

    Cena, Lorenzo G; Peters, Thomas M

    2011-02-01

    This work characterized airborne particles generated from the weighing of bulk, multiwall carbon nanotubes (CNTs) and the manual sanding of epoxy test samples reinforced with CNTs. It also evaluated the effectiveness of three local exhaust ventilation (LEV) conditions (no LEV, custom fume hood, and biosafety cabinet) for control of particles generated during sanding of CNT-epoxy nanocomposites. Particle number and respirable mass concentrations were measured using an optical particle counter (OPC) and a condensation particle counter (CPC), and particle morphology was assessed by transmission electron microscopy. The ratios of the geometric mean (GM) concentrations measured during the process to that measured in the background (P/B ratios) were used as indices of the impact of the process and the LEVs on observed concentrations. Processing CNT-epoxy nanocomposites materials released respirable size airborne particles (P/B ratio: weighing = 1.79; sanding = 5.90) but generally no nanoparticles (P/B ratio ?1). The particles generated during sanding were predominantly micron sized with protruding CNTs and very different from bulk CNTs that tended to remain in large (>1 ?m) tangled clusters. Respirable mass concentrations in the operator's breathing zone were lower when sanding was performed in the biological safety cabinet (GM = 0.20 ?g/m(3) compared with those with no LEV (GM = 2.68 ?g/m(3) or those when sanding was performed inside the fume hood (GM = 21.4 ?g/m(3); p-value < 0.0001). The poor performance of the custom fume hood used in this study may have been exacerbated by its lack of a front sash and rear baffles and its low face velocity (0.39 m/sec). PMID:21253981

  15. METHODS FOR ANALYZING INORGANIC COMPOUNDS IN PARTICLES EMITTED FROM STATIONARY SOURCES

    EPA Science Inventory

    The research described was initiated with the objective of developing methods to identify and measure inorganic compounds in particulate emissions which emanate from sources using or processing fossil fuels. An extensive literature review was carried out to ascertain prior knowle...

  16. Evolution of trace gases and particles emitted by a chaparral fire in California

    NASA Astrophysics Data System (ADS)

    Akagi, S. K.; Craven, J. S.; Taylor, J. W.; McMeeking, G. R.; Yokelson, R. J.; Burling, I. R.; Urbanski, S. P.; Wold, C. E.; Seinfeld, J. H.; Coe, H.; Alvarado, M. J.; Weise, D. R.

    2012-02-01

    Biomass burning (BB) is a major global source of trace gases and particles. Accurately representing the production and evolution of these emissions is an important goal for atmospheric chemical transport models. We measured a suite of gases and aerosols emitted from an 81 hectare prescribed fire in chaparral fuels on the central coast of California, US on 17 November 2009. We also measured physical and chemical changes that occurred in the isolated downwind plume in the first ~4 h after emission. The measurements were carried out onboard a Twin Otter aircraft outfitted with an airborne Fourier transform infrared spectrometer (AFTIR), aerosol mass spectrometer (AMS), single particle soot photometer (SP2), nephelometer, LiCor CO2 analyzer, a chemiluminescence ozone instrument, and a wing-mounted meteorological probe. Our measurements included: CO2; CO; NOx; NH3; non-methane organic compounds; organic aerosol (OA); inorganic aerosol (nitrate, ammonium, sulfate, and chloride); aerosol light scattering; refractory black carbon (rBC); and ambient temperature, relative humidity, barometric pressure, and three-dimensional wind velocity. The molar ratio of excess O3 to excess CO in the plume (ΔO3/ΔCO) increased from -5.13 (±1.13) × 10-3 to 10.2 (±2.16) × 10-2 in ~4.5 h following smoke emission. Excess acetic and formic acid (normalized to excess CO) increased by factors of 1.73 ± 0.43 and 7.34 ± 3.03 (respectively) over the same time since emission. Based on the rapid decay of C2H4 we infer an in-plume average OH concentration of 5.27 (±0.97) × 106 molec cm-3, consistent with previous studies showing elevated OH concentrations in biomass burning plumes. Ammonium, nitrate, and sulfate all increased over the course of 4 h. The observed ammonium increase was a factor of 3.90 ± 2.93 in about 4 h, but accounted for just ~36% of the gaseous ammonia lost on a molar basis. Some of the gas phase NH3 loss may have been due to condensation on, or formation of, particles below the AMS detection range. NOx was converted to PAN and particle nitrate with PAN production being about two times greater than production of observable nitrate in the first ~4 h following emission. The excess aerosol light scattering in the plume (normalized to excess CO2) increased by a factor of 2.50 ± 0.74 over 4 h. The increase in light scattering was similar to that observed in an earlier study of a biomass burning plume in Mexico where significant secondary formation of OA closely tracked the increase in scattering. In the California plume, however, ΔOA/ΔCO2 decreased sharply for the first hour and then increased slowly with a net decrease of ~20% over 4 h. The fraction of thickly coated rBC particles increased up to ~85% over the 4 h aging period. Decreasing OA accompanied by increased scattering/particle coating in initial aging may be due to a combination of particle coagulation and evaporation processes. Recondensation of species initially evaporated from the particles may have contributed to the subsequent slow rise in OA. We compare our results to observations from other plume aging studies and suggest that differences in environmental factors such as smoke concentration, oxidant concentration, actinic flux, and RH contribute significantly to the variation in plume evolution observations.

  17. Evolution of trace gases and particles emitted by a chaparral fire in California

    NASA Astrophysics Data System (ADS)

    Akagi, S. K.; Craven, J. S.; Taylor, J. W.; McMeeking, G. R.; Yokelson, R. J.; Burling, I. R.; Urbanski, S. P.; Wold, C. E.; Seinfeld, J. H.; Coe, H.; Alvarado, M. J.; Weise, D. R.

    2011-08-01

    Biomass burning (BB) is a major global source of trace gases and particles. Accurately representing the production and evolution of these emissions is an important goal for atmospheric chemical transport models. We measured a suite of gases and aerosols emitted from an 81 ha prescribed fire in chaparral fuels on the central coast of California, US on 17 November 2009. We also measured post-emission chemical changes in the isolated downwind plume for ~4 h of smoke aging. The measurements were carried out on board a Twin Otter aircraft outfitted with an airborne Fourier transform infrared spectrometer (AFTIR), aerosol mass spectrometer (AMS), single particle soot photometer (SP2), nephelometer, LiCor CO2 analyzer, a chemiluminescence ozone instrument, and a wing-mounted meteorological probe. Our measurements included: CO2; CO; NOx; NH3; non-methane organic compounds; organic aerosol (OA); inorganic aerosol (nitrate, ammonium, sulfate, and chloride); aerosol light scattering; refractory black carbon (rBC); and ambient temperature, relative humidity, barometric pressure, and three-dimensional wind velocity. The molar ratio of excess O3 to excess CO in the plume (ΔO3/ΔCO) increased from -0.005 to 0.102 in 4.5 h. Excess acetic and formic acid (normalized to excess CO) increased by factors of 1.7 ± 0.4 and 7.3 ± 3.0 (respectively) over the same aging period. Based on the rapid decay of C2H4 we infer an in-plume average OH concentration of 5.3 (±1.0) × 106 molecules cm-3, consistent with previous studies showing elevated OH concentrations in biomass burning plumes. Ammonium, nitrate, and sulfate all increased with plume aging. The observed ammonium increase was a factor of 3.9 ± 2.6 in about 4 h, but accounted for just ~36 % of the gaseous ammonia lost on a molar basis. Some of the gas phase NH3 loss may have been due to condensation on, or formation of, particles below the AMS detection range. NOx was converted to PAN and particle nitrate with PAN production being about two times greater than production of observable nitrate over a 4 h aging period. The excess aerosol light scattering in the plume (normalized to excess CO2) increased by a factor of 2.3 ± 0.7 over 4 h. The increase in light scattering was similar to that observed in an earlier study of a biomass burning plume in Mexico where significant secondary formation of OA closely tracked the increase in scattering. In the California plume, however, ΔOA/ΔCO2 decreased sharply for the first hour and then increased slowly with a net decrease of ~24 % over 4 h. The fraction of thickly coated rBC particles increased almost twofold over the 4 h aging period. Decreasing OA accompanied by increased scattering/coating in the initial aging may be due to a combination of particle coagulation and evaporation processes. Recondensation of species initially evaporated from the particles may have contributed to the subsequent slow rise in OA. We compare our results to observations from other plume aging studies and suggest that differences in environmental factors such as smoke concentration, oxidant concentration, actinic flux, and RH contribute significantly to the variation in plume evolution observations.

  18. [Characteristics of water soluble inorganic ions in fine particles emitted from coal-fired power plants].

    PubMed

    Duan, Lei; Ma, Zi-Zhen; Li, Zhen; Jiang, Jing-Kun; Ye, Zhi-Xiang

    2015-03-01

    Currently, China suffers from serious pollution of fine particulate matter (PM2.5). Coal-fired power plant is one of the most important sources of PM2.5 in the atmosphere. To achieve the national goals of total emission reductions of sulfur dioxide (SO2) and nitrogen oxides (NO(x)) during the 11th and 12th Five-Year Plan, most of coal-fired power plants in China have installed or will install flue gas desulfurization (FGD) and flue gas denitrification (DNO(x)) systems. As a result, the secondary PM2.5, generated from gaseous pollutants in the atmosphere, would be decreased. However, the physical and chemical characteristics of PM2.5 in flue gas would be affected, and the emission of primary PM2.5 might be increased. This paper summarized the size distributions of PM2.5 and its water soluble ions emitted from coal-fired power plants, and highlighted the effects of FGD and DNO(x) on PM2.5 emission, especially on water soluble ions (such as SO4(2-), Ca2+ and NH4+) in PM2.5. Under the current condition of serious PM2.5 pollution and wide application of FGD and DNO(x), quantitative study on the effects of FGD and DNO(x) installation on emission characteristics of PM2.5 from coal-fired power plants is of great necessity. PMID:25929084

  19. Identification of platinum and palladium particles emitted from vehicles and dispersed into the surface environment.

    PubMed

    Prichard, Hazel M; Fisher, Peter C

    2012-03-20

    Platinum, palladium, and rhodium are emitted from vehicle catalytic converters. Until now, the form of precious metal particles in road dust and urban waste has not been identified. This study has located, imaged, and analyzed these particles in road dust and gully waste. Two fragments of catalytic converter have been observed in road dust. They are 40-80 μm in size and covered in many minute particles (<0.3 μm) of either platinum with minor rhodium or palladium. One fragment identified in gully sediment is smaller, 25 μm in diameter, hosting only one attached particle of palladium with minor rhodium. As fragments are washed off roads they begin to disintegrate and the precious metals become detached. Also precious metal-bearing particles have been located in incinerated sewage ash including a 20 μm diameter cluster of <3 μm sized platinum particles that may be the remains of a catalytic converter fragment that has survived incineration. The form of these precious metal-bearing particles described here reveals that as they are dispersed from roads they are likely to be present predominantly as two particle sizes. Either they are attached to larger fragments of catalytic converter or they are released as individual detached tiny <0.3 μm to nanoparticle sizes. PMID:22313190

  20. A Model to Predict the Breathing Zone Concentrations of Particles Emitted from Surfaces

    EPA Science Inventory

    Activity based sampling (ABS) is typically performed to assess inhalation exposure to particulate contaminants known to have low, heterogeneous concentrations on a surface. Activity based sampling determines the contaminant concentration in a person's breathing zone as they perfo...