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Sample records for 72-amino-acid residue precursor

  1. Four residues of propeptide are essential for precursor folding of nattokinase.

    PubMed

    Jia, Yan; Cao, Xinhua; Deng, Yu; Bao, Wei; Tang, Changyan; Ding, Hanjing; Zheng, Zhongliang; Zou, Guolin

    2014-11-01

    Subtilisin propeptide functions as an intramolecular chaperone that guides precursor folding. Nattokinase, a member of subtilisin family, is synthesized as a precursor consisting of a signal peptide, a propeptide, and a subtilisin domain, and the mechanism of its folding remains to be understood. In this study, the essential residues of nattokinase propeptide which contribute to precursor folding were determined. Deletion analysis showed that the conserved regions in propeptide were important for precursor folding. Single-site and multi-site mutagenesis studies confirmed the role of Tyr10, Gly13, Gly34, and Gly35. During stage (i) and (ii) of precursor folding, Tyr10 and Gly13 would form the part of interface with subtilisin domain. While Gly34 and Gly35 connected with an α-helix that would stabilize the structure of propeptide. The quadruple Ala mutation, Y10A/G13A/G34A/G35A, resulted in a loss of the chaperone function for the propeptide. This work showed the essential residues of propeptide for precursor folding via secondary structure and kinetic parameter analyses.

  2. Triphosphate residues at the 5' ends of rRNA precursor and 5S RNA from Dictyostelium discoideum.

    PubMed Central

    Batts-Young, B; Lodish, H F

    1978-01-01

    We present here direct evidence for the preservation of a transcriptional initiation sequence in a eukaryotic rRNA precursor: the 5'-end group for precursor to 17S rRNA (p17S RNA) from Dictyostelium discoideum is identified as the triphosphate residue pppA-. We also show that mature 5S RNA form Dictyostelium bears a different triphosphate residue, pppG-. In contrast, we find no evidence for more than one phosphate at the 5' end of the 25S rRNA precursor (p25S RNA). These observations indicate that synthesis of the large ribosomal RNAs of Dictyostelium begins with the 5'-terminal sequence of the p17S RNA, and that 5S RNA transcription must be initiated independently, despite the close association of the 5S and rRNA coding segments. Images PMID:204930

  3. A hierarchical structure through imprinting of a polyimide precursor without residual layers

    NASA Astrophysics Data System (ADS)

    Pai, I.-Ting; Leu, Ing-Chi; Hon, Min-Hsiung

    2008-10-01

    A patterned polyimide without a residual layer is obtained by imprinting with the assistance of a residual solvent. The effects of the wetting behaviors of the poly-amic acid (PAA) solution coated on various surfaces are examined and the formation of hierarchical patterns without residual layers is demonstrated. polydimethylsiloxane (PDMS) and PEI/PDMS are used as imprinting molds with Si and 300 nm SiO2/Si as substrates. The results indicate that the various ambits of patterns without a residual layer are formed due to the dewetting phenomena caused by surface tension (Suh 2006 Small 2 832). During imprinting, PDMS with a low surface energy makes the PAA solution flow away from its surface exposing the contact area due to dewetting. Self-organized hierarchical structures are also obtained from this process due to effective dewetting. The present study provides a new approach for fabricating patterns without residual layers and the consequent preparation of hierarchical structures, which is considered to be impossible using the lithographic technique.

  4. Release of nitrogen precursors from coal and biomass residues in a bubbling fluidized bed

    SciTech Connect

    P. Abelha; I. Gulyurtlu; I. Cabrita

    2008-01-15

    This work was undertaken with the aim of quantifying the relative amounts of NH{sub 3} and HCN released from different residues during their devolatilization under fluidized bed conditions. The results were compared with data collected for bituminous coals of different origin. The relation between amounts of HCN and NH{sub 3} released and the levels of NOX and N{sub 2}O formed during cocombustion was also addressed. The partitioning of nitrogen between volatiles and char was also quantified. The pyrolysis studies were undertaken in a small fluidized bed reactor of 80 mm of ID and 500 mm high using an inert atmosphere (N{sub 2}). The HCN and NH{sub 3} were quantified by bubbling the pyrolysis gases in absorbing solutions which were subsequently analyzed with selective electrodes. The combustion studies were carried out on a pilot installation. The fluidized bed combustor is square in cross section with each side being 300 mm long. There is secondary air supply to the freeboard at different heights to deal with high volatile fuels as almost all waste materials are. The temperatures in the bed and in the freeboard and that of the flue gases leaving the reactor were continuously monitored. The results obtained suggest that, while coal releases nitrogen mostly as HCN, residues like RDF and sewage sludge give out fuel-N in greater quantities as NH{sub 3}. Residues at fluidized bed combustion (FBC) temperatures release more than 80% of the fuel-N with the volatiles. The NH{sub 3} evolved during pyrolysis acted as a reducing agent on NOX emissions. The presence of calcium significantly reduces the emission of N{sub 2}O probably by interfering with HCN chemistry. With high amounts of residues in the fuel mixture, the relative importance of char on the nitrogen chemistry substantially decreases. By using cocombustion, it is possible to reduce fuel-N conversion to NOX and N{sub 2}O, by tuning the amounts of coal and residue in the mixture. 29 refs., 18 figs., 3 tabs.

  5. A petrologic, thermodynamic and experimental study of brachinites: Partial melt residues of an R chondrite-like precursor

    NASA Astrophysics Data System (ADS)

    Gardner-Vandy, Kathryn G.; Lauretta, Dante S.; McCoy, Timothy J.

    2013-12-01

    The primitive achondrites provide a window into the initial melting of asteroids in the early solar system. The brachinites are olivine-dominated meteorites with a recrystallized texture that we and others interpret as evidence of partial melting and melt removal on the brachinite parent body. We present a petrologic, thermodynamic and experimental study of the brachinites to evaluate the conditions under which they formed and test our hypothesis that the precursor material to the brachinites was FeO-rich compared to the precursors of other primitive achondrites. Petrologic analysis of six brachinites (Brachina, Allan Hills (ALH) 84025, Hughes 026, Elephant Moraine (EET) 99402, Northwest Africa (NWA) 3151, and NWA 4969) and one brachinite-like achondrite (NWA 5400) shows that they are meteorites with recrystallized texture that are enriched in olivine (⩾80 vol.%) and depleted in other minerals with respect to a chondritic mineralogy. Silicates in the brachinites are FeO-rich (Fa32-36). Brachinite-like achondrite Northwest Africa 5400 is similar in mineralogy and texture to the brachinites but with a slightly lower FeO-content (Fa30). Thermodynamic calculations yield equilibration temperatures above the Fe,Ni-FeS cotectic temperature (∼950 °C) for all meteorites studied here and temperatures above the silicate eutectic (∼1050 °C) for all but two. Brachina formed at an fO2 of ∼IW, and the other brachinites and NWA 5400 formed at ∼IW - 1. All the meteorites show great evidence of formation by partial melting having approximately chondritic to depleted chondritic mineralogies, equilibrated mineral compositions, and recrystallized textures, and having reached temperatures above that required for melt generation. In an attempt to simulate the formation of the brachinite meteorites, we performed one-atmosphere, gas-mixing partial melting experiments of R4 chondrite LaPaz Ice Field 03639. Experiments at 1250 °C and an oxygen fugacity of IW - 1 produce residual

  6. Obesity is associated with residual leukemia following induction therapy for childhood B-precursor acute lymphoblastic leukemia.

    PubMed

    Orgel, Etan; Tucci, Jonathan; Alhushki, Waseem; Malvar, Jemily; Sposto, Richard; Fu, Cecilia H; Freyer, David R; Abdel-Azim, Hisham; Mittelman, Steven D

    2014-12-18

    Obesity is associated with poorer event-free survival (EFS) in pediatric acute lymphoblastic leukemia (ALL). Persistent minimal residual disease (MRD) in the bone marrow as measured by multidimensional flow cytometry (MDF) is a key early prognostic indicator and is strongly associated with EFS. We therefore hypothesized that obesity during induction would be associated with positive end-of-induction MRD (≥0.01%). We analyzed MDF of end-induction bone marrow samples from a historical cohort of 198 children newly diagnosed with B-precursor ALL (BP-ALL) and treated with Children's Oncology Group induction regimens. We assessed the influence of body mass index on risk for positive end-induction MRD in the bone marrow. In our cohort of BP-ALL, 30 children (15.2%) were overweight and 41 (20.7%) were obese at diagnosis. Independent of established predictors of treatment response, obesity during induction was associated with significantly greater risk for persistent MRD (odds ratio, 2.57; 95% confidence interval, 1.19 to 5.54; P = .016). Obesity and overweight were associated with poorer EFS irrespective of end-induction MRD (P = .012). Obese children with newly diagnosed BP-ALL are at increased risk for positive end-induction MRD and poorer EFS.

  7. A Functional Interplay between Human Immunodeficiency Virus Type 1 Protease Residues 77 and 93 Involved in Differential Regulation of Precursor Autoprocessing and Mature Protease Activity

    PubMed Central

    Counts, Christopher J.; Ho, P. Shing; Donlin, Maureen J.; Tavis, John E.; Chen, Chaoping

    2015-01-01

    HIV-1 protease (PR) is a viral enzyme vital to the production of infectious virions. It is initially synthesized as part of the Gag-Pol polyprotein precursor in the infected cell. The free mature PR is liberated as a result of precursor autoprocessing upon virion release. We previously described a model system to examine autoprocessing in transfected mammalian cells. Here, we report that a covariance analysis of miniprecursor (p6*-PR) sequences derived from drug naïve patients identified a series of amino acid pairs that vary together across independent viral isolates. These covariance pairs were used to build the first topology map of the miniprecursor that suggests high levels of interaction between the p6* peptide and the mature PR. Additionally, several PR-PR covariance pairs are located far from each other (>12 Å Cα to Cα) relative to their positions in the mature PR structure. Biochemical characterization of one such covariance pair (77–93) revealed that each residue shows distinct preference for one of three alkyl amino acids (V, I, and L) and that a polar or charged amino acid at either of these two positions abolishes precursor autoprocessing. The most commonly observed 77V is preferred by the most commonly observed 93I, but the 77I variant is preferred by other 93 variances (L, V, or M) in supporting precursor autoprocessing. Furthermore, the 77I93V covariant enhanced precursor autoprocessing and Gag polyprotein processing but decreased the mature PR activity. Therefore, both covariance and biochemical analyses support a functional association between residues 77 and 93, which are spatially distant from each other in the mature PR structure. Our data also suggests that these covariance pairs differentially regulate precursor autoprocessing and the mature protease activity. PMID:25893662

  8. A Functional Interplay between Human Immunodeficiency Virus Type 1 Protease Residues 77 and 93 Involved in Differential Regulation of Precursor Autoprocessing and Mature Protease Activity.

    PubMed

    Counts, Christopher J; Ho, P Shing; Donlin, Maureen J; Tavis, John E; Chen, Chaoping

    2015-01-01

    HIV-1 protease (PR) is a viral enzyme vital to the production of infectious virions. It is initially synthesized as part of the Gag-Pol polyprotein precursor in the infected cell. The free mature PR is liberated as a result of precursor autoprocessing upon virion release. We previously described a model system to examine autoprocessing in transfected mammalian cells. Here, we report that a covariance analysis of miniprecursor (p6*-PR) sequences derived from drug naïve patients identified a series of amino acid pairs that vary together across independent viral isolates. These covariance pairs were used to build the first topology map of the miniprecursor that suggests high levels of interaction between the p6* peptide and the mature PR. Additionally, several PR-PR covariance pairs are located far from each other (>12 Å Cα to Cα) relative to their positions in the mature PR structure. Biochemical characterization of one such covariance pair (77-93) revealed that each residue shows distinct preference for one of three alkyl amino acids (V, I, and L) and that a polar or charged amino acid at either of these two positions abolishes precursor autoprocessing. The most commonly observed 77V is preferred by the most commonly observed 93I, but the 77I variant is preferred by other 93 variances (L, V, or M) in supporting precursor autoprocessing. Furthermore, the 77I93V covariant enhanced precursor autoprocessing and Gag polyprotein processing but decreased the mature PR activity. Therefore, both covariance and biochemical analyses support a functional association between residues 77 and 93, which are spatially distant from each other in the mature PR structure. Our data also suggests that these covariance pairs differentially regulate precursor autoprocessing and the mature protease activity.

  9. A petrologic and isotopic study of lodranites: Evidence for early formation as partial melt residues from heterogeneous precursors

    NASA Astrophysics Data System (ADS)

    McCoy, T. J.; Keil, K.; Clayton, R. N.; Mayeda, T. K.; Bogard, D. D.; Garrison, D. H.; Wieler, R.

    1997-02-01

    We have conducted petrologic, chemical, and isotopic studies of lodranites in an attempt to constrain their genesis. Lodran, Gibson, Y-791491, Y-791493, Y-74357, Y-8002, Y-75274, MAC 88177, LEW 88280, EET 84302, FRO 90011, and QUE 93148 are classified as lodranites. Lodranites and acapulcoites are indistinguishable on the basis of oxygen isotopic compositions but are distinct in average grain sizes of their mafic silicates, with lodranites being significantly coarser-grained. Lodranites exhibit a diverse range of petrologic and mineralogic features: they range widely in mafic silicate compositions (Fa 3-13), plagioclase (0-11.4 vol%), Fe,Ni metal (0.5-20 vol%), and troilite (0.2-5.3 vol%) contents; and shock levels (S1-S4) . They appear to have experienced high peak temperatures and rapid cooling in the temperature range recorded by metallographic cooling rates (i.e., 700-350°C). The only dated lodranite, Gibson, cooled to Ar closure temperatures at 4.49 ± 0.01 Ga. Lodranites formed from chemically and isotopically heterogeneous precursors in which the mineral and oxygen isotopic compositions were correlated. Heating of their parent body to temperatures between ˜ 1050-1200°C resulted in formation of Fe,NiFeS and basaltic partial melts. Depletions of troilite and/ or plagioclase in most lodranites testify to the removal of some of these partial melts, although melt migration was complex. Lodranites appear to have experienced a complex cooling history of slow cooling at high temperatures, followed by rapid cooling at intermediate temperatures, possibly related to breakup of the parent body. Lodranites were liberated from their parent body during 1-3 impact events, with most having cosmic ray exposure ages of 5.5-7 Ma. The acapulcoites are samples from the same parent body but were heated to lower temperatures and, thus, experienced lower degrees of partial melting.

  10. Translocation of the precursor of 5-enolpyruvylshikimate-3-phosphate synthase into chloroplasts of higher plants in vitro

    PubMed Central

    Della-Cioppa, Guy; Bauer, S. Christopher; Klein, Barbara K.; Shah, Dilip M.; Fraley, Robert T.; Kishore, Ganesh M.

    1986-01-01

    5-enolPyruvylshikimate-3-phosphate synthase (EPSP synthase; 3-phosphoshikimate 1-carboxyvinyl-transferase; EC 2.5.1.19) is a chloroplast-localized enzyme of the shikimate pathway in plants. This enzyme is the target for the nonselective herbicide glyphosate (N-phosphonomethylglycine). We have previously isolated a full-length cDNA clone of EPSP synthase from Petunia hybrida. DNA sequence analysis suggested that the enzyme is synthesized as a cytosolic precursor (pre-EPSP synthase) with an amino-terminal transit peptide. Based on the known amino terminus of the mature enzyme, and the 5′ open reading frame of the cDNA, the transit peptide of pre-EPSP synthase would be maximally 72 amino acids long. To confirm this prediction and to assay directly for translocation of pre-EPSP synthase into chloroplasts in vitro, we cloned the full-length cDNA into an SP6 transcription system to produce large amounts of mRNA for in vitro translation. The translation products, when analyzed by NaDodSO4/PAGE autoradiography, indicate a relative molecular mass for pre-EPSP synthase of ≈55 kDa. Uptake studies with intact chloroplasts, in vitro, indicate that pre-EPSP synthase was rapidly taken up into chloroplasts and proteolytically cleaved to the mature ≈48-kDa enzyme. The transit peptide was shown to be essential for import of the precursor enzyme into the chloroplast. To our knowledge, post-translational import into chloroplasts of a precursor enzyme involved in amino acid biosynthesis has not been reported previously. Furthermore, enzymatic analysis of translation products indicates that pre-EPSP synthase is catalytically active and has a similar sensitivity to the herbicide glyphosate as the mature enzyme. To our knowledge, pre-EPSP synthase represents the only example of a catalytically competent chloroplast-precursor enzyme. Images PMID:16593759

  11. Genetic selection of sox1GFP-expressing neural precursors removes residual tumorigenic pluripotent stem cells and attenuates tumor formation after transplantation

    PubMed Central

    Chung, S.; Shin, B.-S.; Hedlund, E.; Pruszak, J.; Ferree, A.; Kang, Un Jung; Isacson, Ole; Kim, Kwang-Soo

    2008-01-01

    Because of their ability to proliferate and to differentiate into diverse cell types, embryonic stem (ES) cells are a potential source of cells for transplantation therapy of various diseases, including Parkinson’s disease. A critical issue for this potential therapy is the elimination of undifferentiated cells that, even in low numbers, could result in teratoma formation in the host brain. We hypothesize that an efficient solution would consist of purifying the desired cell types, such as neural precursors, prior to transplantation. To test this hypothesis, we differentiated sox1-green fluorescent protein (GFP) knock-in ES cells in vitro, purified neural precursor cells by fluorescence-activated cell sorting (FACS), and characterized the purified cells in vitro as well as in vivo. Immunocytofluorescence and RT-PCR analyses showed that this genetic purification procedure efficiently removed undifferentiated pluripotent stem cells. Furthermore, when differentiated into mature neurons in vitro, the purified GFP+ cell population generated enriched neuronal populations, whereas the GFP− population generated much fewer neurons. When treated with dopaminergic inducing signals such as sonic hedgehog (SHH) and fibroblast growth factor-8 (FGF8), FACS-purified neural precursor cells responded to these molecules and generated dopaminergic neurons as well as other neural subtypes. When transplanted, the GFP+ cell population generated well contained grafts containing dopaminergic neurons, whereas the GFP− population generated significantly larger grafts (about 20-fold) and frequent tumor-related deaths in the transplanted animals. Taken together, our results demonstrate that genetic purification of neural precursor cells using FACS isolation can effectively remove unwanted proliferating cell types and avoid tumor formation after transplantation. PMID:16696855

  12. Association of germline genetic variants in RFC, IL15 and VDR genes with minimal residual disease in pediatric B-cell precursor ALL

    PubMed Central

    Dawidowska, Małgorzata; Kosmalska, Maria; Sędek, Łukasz; Szczepankiewicz, Aleksandra; Twardoch, Magdalena; Sonsala, Alicja; Szarzyńska-Zawadzka, Bronisława; Derwich, Katarzyna; Lejman, Monika; Pawelec, Katarzyna; Obitko-Płudowska, Agnieszka; Pawińska-Wąsikowska, Katarzyna; Kwiecińska, Kinga; Kołtan, Andrzej; Dyla, Agnieszka; Grzeszczak, Władysław; Kowalczyk, Jerzy R.; Szczepański, Tomasz; Ziętkiewicz, Ewa; Witt, Michał

    2016-01-01

    Minimal residual disease (MRD) enables reliable assessment of risk in acute lymphoblastic leukemia (ALL). However, little is known on association between MRD status and germline genetic variation. We examined 159 Caucasian (Slavic) patients with pediatric ALL, treated according to ALL-IC-BFM 2002/2009 protocols, in search for association between 23 germline polymorphisms and MRD status at day 15, day 33 and week 12, with adjustment for MRD-associated clinical covariates. Three variants were significantly associated with MRD: rs1544410 in VDR (MRD-day15); rs1051266 in RFC (MRD-day33, MRD-week12), independently and in an additive effect with rs10519613 in IL15 (MRD-day33). The risk alleles for MRD-positivity were: A allele of VDR (OR = 2.37, 95%CI = 1.07–5.21, P = 0.03, MRD-day15); A of RFC (OR = 1.93, 95%CI = 1.05–3.52, P = 0.03, MRD-day33 and MRD-week12, P < 0.01); A of IL15 (OR = 2.30, 95%CI = 1.02–5.18, P = 0.04, MRD-day33). The risk for MRD-day33-positive status was higher in patients with risk alleles in both RFC and IL15 loci than in patients with risk alleles in one locus or no risk alleles: 2 vs. 1 (OR = 3.94, 95% CI = 1.28–12.11, P = 0.024), 2 vs. 0 (OR = 6.75, 95% CI = 1.61–28.39, P = 0.012). Germline variation in genes related to pharmacokinetics/pharmacodynamics of anti-leukemic drugs and to anti-tumor immunity of the host is associated with MRD status and might help improve risk assessment in ALL. PMID:27427275

  13. Association of germline genetic variants in RFC, IL15 and VDR genes with minimal residual disease in pediatric B-cell precursor ALL.

    PubMed

    Dawidowska, Małgorzata; Kosmalska, Maria; Sędek, Łukasz; Szczepankiewicz, Aleksandra; Twardoch, Magdalena; Sonsala, Alicja; Szarzyńska-Zawadzka, Bronisława; Derwich, Katarzyna; Lejman, Monika; Pawelec, Katarzyna; Obitko-Płudowska, Agnieszka; Pawińska-Wąsikowska, Katarzyna; Kwiecińska, Kinga; Kołtan, Andrzej; Dyla, Agnieszka; Grzeszczak, Władysław; Kowalczyk, Jerzy R; Szczepański, Tomasz; Ziętkiewicz, Ewa; Witt, Michał

    2016-01-01

    Minimal residual disease (MRD) enables reliable assessment of risk in acute lymphoblastic leukemia (ALL). However, little is known on association between MRD status and germline genetic variation. We examined 159 Caucasian (Slavic) patients with pediatric ALL, treated according to ALL-IC-BFM 2002/2009 protocols, in search for association between 23 germline polymorphisms and MRD status at day 15, day 33 and week 12, with adjustment for MRD-associated clinical covariates. Three variants were significantly associated with MRD: rs1544410 in VDR (MRD-day15); rs1051266 in RFC (MRD-day33, MRD-week12), independently and in an additive effect with rs10519613 in IL15 (MRD-day33). The risk alleles for MRD-positivity were: A allele of VDR (OR = 2.37, 95%CI = 1.07-5.21, P = 0.03, MRD-day15); A of RFC (OR = 1.93, 95%CI = 1.05-3.52, P = 0.03, MRD-day33 and MRD-week12, P < 0.01); A of IL15 (OR = 2.30, 95%CI = 1.02-5.18, P = 0.04, MRD-day33). The risk for MRD-day33-positive status was higher in patients with risk alleles in both RFC and IL15 loci than in patients with risk alleles in one locus or no risk alleles: 2 vs. 1 (OR = 3.94, 95% CI = 1.28-12.11, P = 0.024), 2 vs. 0 (OR = 6.75, 95% CI = 1.61-28.39, P = 0.012). Germline variation in genes related to pharmacokinetics/pharmacodynamics of anti-leukemic drugs and to anti-tumor immunity of the host is associated with MRD status and might help improve risk assessment in ALL. PMID:27427275

  14. The Pseudomonas aeruginosa antimetabolite L -2-amino-4-methoxy-trans-3-butenoic acid (AMB) is made from glutamate and two alanine residues via a thiotemplate-linked tripeptide precursor

    PubMed Central

    Rojas Murcia, Nelson; Lee, Xiaoyun; Waridel, Patrice; Maspoli, Alessandro; Imker, Heidi J.; Chai, Tiancong; Walsh, Christopher T.; Reimmann, Cornelia

    2015-01-01

    The Pseudomonas aeruginosa toxin L-2-amino-4-methoxy-trans-3-butenoic acid (AMB) is a non-proteinogenic amino acid which is toxic for prokaryotes and eukaryotes. Production of AMB requires a five-gene cluster encoding a putative LysE-type transporter (AmbA), two non-ribosomal peptide synthetases (AmbB and AmbE), and two iron(II)/α-ketoglutarate-dependent oxygenases (AmbC and AmbD). Bioinformatics analysis predicts one thiolation (T) domain for AmbB and two T domains (T1 and T2) for AmbE, suggesting that AMB is generated by a processing step from a precursor tripeptide assembled on a thiotemplate. Using a combination of ATP-PPi exchange assays, aminoacylation assays, and mass spectrometry-based analysis of enzyme-bound substrates and pathway intermediates, the AmbB substrate was identified to be L-alanine (L-Ala), while the T1 and T2 domains of AmbE were loaded with L-glutamate (L-Glu) and L-Ala, respectively. Loading of L-Ala at T2 of AmbE occurred only in the presence of AmbB, indicative of a trans loading mechanism. In vitro assays performed with AmbB and AmbE revealed the dipeptide L-Glu-L-Ala at T1 and the tripeptide L-Ala-L-Glu-L-Ala attached at T2. When AmbC and AmbD were included in the assay, these peptides were no longer detected. Instead, an L-Ala-AMB-L-Ala tripeptide was found at T2. These data are in agreement with a biosynthetic model in which L-Glu is converted into AMB by the action of AmbC, AmbD, and tailoring domains of AmbE. The importance of the flanking L-Ala residues in the precursor tripeptide is discussed. PMID:25814981

  15. The clinical impact of IKZF1 deletions in paediatric B-cell precursor acute lymphoblastic leukaemia is independent of minimal residual disease stratification in Nordic Society for Paediatric Haematology and Oncology treatment protocols used between 1992 and 2013.

    PubMed

    Olsson, Linda; Ivanov Öfverholm, Ingegerd; Norén-Nyström, Ulrika; Zachariadis, Vasilios; Nordlund, Jessica; Sjögren, Helene; Golovleva, Irina; Nordgren, Ann; Paulsson, Kajsa; Heyman, Mats; Barbany, Gisela; Johansson, Bertil

    2015-09-01

    Paediatric B-cell precursor acute lymphoblastic leukaemias (BCP ALL) with IKZF1 deletions (∆IKZF1) are associated with a poor outcome. However, there are conflicting data as to whether ∆IKZF1 is an independent risk factor if minimal residual disease (MRD) and other copy number alterations also are taken into account. We investigated 334 paediatric BCP ALL, diagnosed 1992-2013 and treated according to Nordic Society for Paediatric Haematology and Oncology ALL protocols, with known IKZF1 status based on either single nucleotide polymorphism array (N = 218) or multiplex ligation-dependent probe amplification (N = 116) analyses. ∆IKZF1, found in 15%, was associated with inferior 10-year probabilities of event-free (60% vs. 83%; P < 0·001) and overall survival (pOS; 73% vs. 89%; P = 0·001). Adjusting for known risk factors, including white blood cell (WBC) count and MRD, ∆IKZF1 was the strongest independent factor for relapse and death. ∆IKZF1 was present in 27% of cases with non-informative cytogenetics ('BCP-other') and a poor 10-year pOS was particularly pronounced in this group (58% vs. 90%; P < 0·001). Importantly, neither MRD nor WBC count predicted events in the ∆IKZF1-positive cases. Co-occurrence of pseudoautosomal region 1 (PAR1) deletions in Xp22.33/Yp11.32 (P2RY8-CRLF2) and ∆IKZF1 increased the risk of relapse (75% vs. 30% for cases with only ∆IKZF1; P = 0·045), indicating that BCP-other ALL with both P2RY8-CRLF2 and ∆IKZF1 constitutes a particularly high-risk group.

  16. Polyimide Precursor Solid Residuum

    NASA Technical Reports Server (NTRS)

    Weiser, Erik S. (Inventor); St.Clair, Terry L. (Inventor); Echigo, Yoshiaki (Inventor); Kaneshiro, Hisayasu (Inventor)

    2001-01-01

    A polyimide precursor solid residuum is an admixture of an aromatic dianhydride or derivative thereof and an aromatic diamine or derivative thereof plus a complexing agent, which is complexed with the admixture by hydrogen bonding. The polyimide precursor solid residuum is effectively employed in the preparation of polyimide foam and the fabrication of polyimide foam structures.

  17. Conformational analysis of amyloid precursor protein fragment containing amino acids 667-676, and the effect of D-Asp and iso-Asp substitution at Asp₆₇₂ residue.

    PubMed

    Shanmugam, Ganesh; Polavarapu, Prasad L; Láng, Emma; Majer, Zsuzsa

    2012-03-01

    Amyloid precursor protein (APP) fragment containing amino acids 667-676, (APP₆₆₇₋₆₇₆), is a substrate for β-secretase which is responsible for generating amyloid β peptides. Conformational analysis of APP₆₆₇₋₆₇₆ peptide [Ac-Ser-Glu-Val-Lys-Met-Asp-Ala-Glu-Phe-Arg-NH₂] and the effect of substitution of Asp₆₇₂ with D-Asp and iso-L-Asp, studied for the first time, demonstrate that the peptide backbone of APP₆₆₇₋₆₇₆ is flexible and adopts different conformations in different solvent environments (water, trifluoroethanol and dimethylsulfoxide). A major conformational difference was observed in trifluoroethanol solvent when Asp₆₇₂ is substituted with D-Asp and iso-Asp. These conformational changes involved in APP₆₆₇₋₆₇₆ may assist in understanding the interactions between β-secretase and APP₆₆₇₋₆₇₆, with relevance to Alzheimer's disease.

  18. Earthquakes: hydrogeochemical precursors

    USGS Publications Warehouse

    Ingebritsen, Steven E.; Manga, Michael

    2014-01-01

    Earthquake prediction is a long-sought goal. Changes in groundwater chemistry before earthquakes in Iceland highlight a potential hydrogeochemical precursor, but such signals must be evaluated in the context of long-term, multiparametric data sets.

  19. Identification of Desirable Precursor Properties for Solution Precursor Plasma Spray

    NASA Astrophysics Data System (ADS)

    Muoto, Chigozie K.; Jordan, Eric H.; Gell, Maurice; Aindow, Mark

    2011-06-01

    In solution precursor plasma spray chemical precursor solutions are injected into a standard plasma torch and the final material is formed and deposited in a single step. This process has several attractive features, including the ability to rapidly explore new compositions and to form amorphous and metastable phases from molecularly mixed precursors. Challenges include: (a) moderate deposition rates due to the need to evaporate the precursor solvent, (b) dealing on a case by case basis with precursor characteristics that influence the spray process (viscosity, endothermic and exothermic reactions, the sequence of physical states through which the precursor passes before attaining the final state, etc.). Desirable precursor properties were identified by comparing an effective precursor for yttria-stabilized zirconia with four less effective candidate precursors for MgO:Y2O3. The critical parameters identified were a lack of major endothermic events during precursor decomposition and highly dense resultant particles.

  20. The EM Earthquake Precursor

    NASA Astrophysics Data System (ADS)

    Jones, K. B., II; Saxton, P. T.

    2013-12-01

    Many attempts have been made to determine a sound forecasting method regarding earthquakes and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic (EM) wave model, various hypotheses were formed, but the most interesting one required the use of a magnetometer with a differing design and geometry. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, something is still amiss. The problem still resides with what exactly is forecastable and the investigating direction of EM. After the 1989 Loma Prieta Earthquake, American earthquake investigators predetermined magnetometer use and a minimum earthquake magnitude necessary for EM detection. This action was set in motion, due to the extensive damage incurred and public outrage concerning earthquake forecasting; however, the magnetometers employed, grounded or buried, are completely subject to static and electric fields and have yet to correlate to an identifiable precursor. Secondly, there is neither a networked array for finding any epicentral locations, nor have there been any attempts to find even one. This methodology needs dismissal, because it is overly complicated, subject to continuous change, and provides no response time. As for the minimum magnitude threshold, which was set at M5, this is simply higher than what modern technological advances have gained. Detection can now be achieved at approximately M1, which greatly improves forecasting chances. A propagating precursor has now been detected in both the field and laboratory. Field antenna testing conducted outside the NE Texas town of Timpson in February, 2013, detected three strong EM sources along with numerous weaker signals. The antenna had mobility, and observations were noted for recurrence, duration, and frequency response. Next, two

  1. Precursors of prostate cancer.

    PubMed

    Bostwick, David G; Cheng, Liang

    2012-01-01

    High-grade prostatic intraepithelial neoplasia (PIN) is the only accepted precursor of prostatic adenocarcinoma, according to numerous studies of animal models and man; other proposed precursors include atrophy and malignancy-associated changes (with no morphologic changes). PIN is characterized by progressive abnormalities of phenotype and genotype that are intermediate between benign prostatic epithelium and cancer, indicating impairment of cell differentiation and regulatory control with advancing stages of prostatic carcinogenesis. The only method of detection of PIN is biopsy because it does not significantly elevate serum prostate-specific antigen concentration and cannot be detected by ultrasonography. The mean incidence of PIN in biopsies is 9% (range, 4%-16%), representing about 115,000 new cases of isolated PIN diagnosed each year in the United States. The clinical importance of PIN is its high predictive value as a marker for adenocarcinoma, and its identification warrants repeat biopsy for concurrent or subsequent carcinoma, especially when multifocal or observed in association with atypical small acinar proliferation (ASAP). Carcinoma develops in most patients with PIN within 10 years. Androgen deprivation therapy and radiation therapy decrease the prevalence and extent of PIN, suggesting that these forms of treatment may play a role in prevention of subsequent cancer. Multiple clinical trials to date of men with PIN have had modest success in delaying or preventing subsequent cancer. PMID:22212075

  2. Chemical preparation and shock wave compression of carbon nitride precursors

    SciTech Connect

    Wixon, M.R. )

    1990-07-01

    Two synthetic routes have been developed to produce high-molecular-weight organic precursors containing a high weight fraction of nitrogen. One of the precursors is a pyrolysis residue of melamine-formaldehyde resin. The second precursor is the byproduct of an unusual low-temperature combustion reaction of tetrazole and its sodium salt. These precursors have been shock compressed under typical conditions for diamond and wurtzite boron nitride synthesis in an attempt to recover a new ultrahard carbon nitride. The recovered material has been analyzed by X-ray diffraction, FTIR, and Raman microprobe analysis. Diamond is present in the recovered material. This diamond is well ordered relative to diamond shock synthesized from carbonaceous starting materials.

  3. Disinfection byproduct formation from lignin precursors.

    PubMed

    Hua, Guanghui; Kim, Junsung; Reckhow, David A

    2014-10-15

    Lignin is the most abundant aromatic plant component in terrestrial ecosystems. This study was conducted to determine the contribution of lignin residues in natural water to the formation of disinfection byproducts (DBPs) in drinking water. We investigated the formation of different classes of DBPs from lignin model compounds, lignin polymers, and humic substances using two common disinfection techniques, chlorination and chloramination. The contributions of lignin to the overall formation of DBPs from these organic products were determined based on the observed abundances of individual lignin phenols and their DBP yields. Model lignin phenols generally produced higher trichloroacetic acid (TCAA) yields than chloroform and dichloroacetic acid (DCAA) during chlorination. Lignin phenols generally produced higher DBP yields but lower percentages of unknown total organic halogen compared to bulk humic substances and lignin polymers. The relative significance of lignin phenols as chlorination DBP precursors generally follows the order of TCAA > DCAA&chloroform. The relative significance of lignin phenols to DBP formation by chloramination follows the order: TCAA > DCAA&DCAN > chloroform. Overall, lignin phenols are more important as TCAA precursors than as chloroform and DCAA precursors.

  4. Formulating Precursors for Coating Metals and Ceramics

    NASA Technical Reports Server (NTRS)

    Morales, Wilfredo; Gatica, Jorge E.; Reye, John T.

    2005-01-01

    A protocol has been devised for formulating low-vapor-pressure precursors for protective and conversion coatings on metallic and ceramic substrates. The ingredients of a precursor to which the protocol applies include additives with phosphate esters, or aryl phosphate esters in solution. Additives can include iron, chromium, and/or other transition metals. Alternative or additional additives can include magnesium compounds to facilitate growth of films on substrates that do not contain magnesium. Formulation of a precursor begins with mixing of the ingredients into a high-vapor-pressure solvent to form a homogeneous solution. Then the solvent is extracted from the solution by evaporation - aided, if necessary, by vacuum and/or slight heating. The solvent is deemed to be completely extracted when the viscosity of the remaining solution closely resembles the viscosity of the phosphate ester or aryl phosphate ester. In addition, satisfactory removal of the solvent can be verified by means of a differential scanning calorimetry essay: the absence of endothermic processes for temperatures below 150 C would indicate that the residual solvent has been eliminated from the solution beyond a detectable dilution level.

  5. An interstellar precursor mission

    NASA Technical Reports Server (NTRS)

    Jaffe, L. D.; Ivie, C.; Lewis, J. C.; Lipes, R. G.; Norton, H. N.; Stearns, J. W.; Stimpson, L.; Weissman, P.

    1977-01-01

    A mission out of the planetary system, with launch about the year 2000, could provide valuable scientific data as well as test some of the technology for a later mission to another star. Primary scientific objectives for the precursor mission concern characteristics of the heliopause, the interstellar medium, stellar distances (by parallax measurements), low energy cosmic rays, interplanetary gas distribution, and mass of the solar system. Secondary objectives include investigation of Pluto. Candidate science instruments are suggested. Individual spacecraft systems for the mission were considered, technology requirements and problem areas noted, and a number of recommendations made for technology study and advanced development. The most critical technology needs include attainment of 50-yr spacecraft lifetime and development of a long-life NEP system.

  6. Identified EM Earthquake Precursors

    NASA Astrophysics Data System (ADS)

    Jones, Kenneth, II; Saxton, Patrick

    2014-05-01

    Many attempts have been made to determine a sound forecasting method regarding earthquakes and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic (EM) wave model, various hypotheses were formed, but the most interesting one required the use of a magnetometer with a differing design and geometry. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, something is still amiss. The problem still resides with what exactly is forecastable and the investigating direction of EM. After a number of custom rock experiments, two hypotheses were formed which could answer the EM wave model. The first hypothesis concerned a sufficient and continuous electron movement either by surface or penetrative flow, and the second regarded a novel approach to radio transmission. Electron flow along fracture surfaces was determined to be inadequate in creating strong EM fields, because rock has a very high electrical resistance making it a high quality insulator. Penetrative flow could not be corroborated as well, because it was discovered that rock was absorbing and confining electrons to a very thin skin depth. Radio wave transmission and detection worked with every single test administered. This hypothesis was reviewed for propagating, long-wave generation with sufficient amplitude, and the capability of penetrating solid rock. Additionally, fracture spaces, either air or ion-filled, can facilitate this concept from great depths and allow for surficial detection. A few propagating precursor signals have been detected in the field occurring with associated phases using custom-built loop antennae. Field testing was conducted in Southern California from 2006-2011, and outside the NE Texas town of Timpson in February, 2013. The antennae have mobility and observations were noted for

  7. Generation of Nonlinear Vortex Precursors.

    PubMed

    Chen, Yue-Yue; Feng, Xun-Li; Liu, Chengpu

    2016-07-01

    We numerically study the propagation of a few-cycle pulse carrying orbital angular momentum (OAM) through a dense atomic system. Nonlinear precursors consisting of high-order vortex harmonics are generated in the transmitted field due to carrier effects associated with ultrafast Bloch oscillation. The nonlinear precursors survive to propagation effects and are well separated with the main pulse, which provides a straightforward way to measure precursors. By virtue of carrying high-order OAM, the obtained vortex precursors as information carriers have potential applications in optical information and communication fields where controllable loss, large information-carrying capacity, and high speed communication are required.

  8. Generation of Nonlinear Vortex Precursors.

    PubMed

    Chen, Yue-Yue; Feng, Xun-Li; Liu, Chengpu

    2016-07-01

    We numerically study the propagation of a few-cycle pulse carrying orbital angular momentum (OAM) through a dense atomic system. Nonlinear precursors consisting of high-order vortex harmonics are generated in the transmitted field due to carrier effects associated with ultrafast Bloch oscillation. The nonlinear precursors survive to propagation effects and are well separated with the main pulse, which provides a straightforward way to measure precursors. By virtue of carrying high-order OAM, the obtained vortex precursors as information carriers have potential applications in optical information and communication fields where controllable loss, large information-carrying capacity, and high speed communication are required. PMID:27447507

  9. Myeloperoxidase is synthesized as larger phosphorylated precursor.

    PubMed Central

    Hasilik, A; Pohlmann, R; Olsen, R L; von Figura, K

    1984-01-01

    Synthesis and processing of myeloperoxidase were examined in metabolically labeled cells of the human promyelocyte line HL-60 and in an in vitro rabbit reticulocyte lysate system directed with HL-60 mRNA. Radioactivity labeled products were isolated by immunoprecipitation and analyzed by gel electrophoresis and fluorography. In vivo, myeloperoxidase was labeled initially as a 85-K glycosylated polypeptide (75 K after treatment with endo-beta-N-acetylglucosaminidase H). This polypeptide was soon processed to an 81-K intermediate and to smaller mature fragments of 60 K and 13 K within approximately 1 day. A minor portion of the precursor was converted to fragments of 40 K and 43 K. The pattern of labeled polypeptides of mature myeloperoxidase was similar to that of the enzyme purified from human leucocytes. The modifications of the polypeptide and of the oligosaccharide side chains in myeloperoxidase resembled those known to occur during the processing of lysosomal enzymes. In the absence or presence of dog pancreas membranes, myeloperoxidase was synthesized in vitro as a 76-K polypeptide or a 87-K glycosylated polypeptide, respectively. In HL-60 cells [32P]phosphate was incorporated into endo-beta-N-acetylglucosaminidase H-sensitive oligosaccharides. The presence of phosphorylated oligosaccharides was inferred from the fact that endocytosis of leucocyte myeloperoxidase in fibroblasts was sensitive to mannose 6-phosphate. It is suggested that myeloperoxidase is synthesized in the rough endoplasmic reticulum as a precursor of larger molecular mass and that the oligosaccharide side chains in the precursor are modified to contain mannose 6-phosphate residues which may be involved in the segregation and transport of the precursor. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. PMID:6096138

  10. An interstellar precursor mission

    NASA Technical Reports Server (NTRS)

    Jaffe, L. D.; Ivie, C.; Lewis, J. C.; Lipes, R.; Norton, H. N.; Stearns, J. W.; Stimpson, L. D.; Weissman, P.

    1980-01-01

    A mission out of the planetary system, launched about the year 2000, could provide valuable scientific data as well as test some of the technology for a later mission to another star. Primary scientific objectives for the precursor mission concern characteristics of the heliopause, the interstellar medium, stellar distances (by parallax measurements), low-energy cosmic rays, interplanetary gas distribution, and the mass of the solar system. Secondary objectives include investigation of Pluto. The mission should extend to 400-1000 AU from the sun. A heliocentric hyperbolic escape velocity of 50-100 km/sec or more is needed to attain this distance within a reasonable mission duration (20-50 years). The trajectory should be toward the incoming interstellar gas. For a year 2000 launch, a Pluto encounter and orbiter can be included. A second mission targeted parallel to the solar axis would also be worthwhile. The mission duration is 20 years, with an extended mission to a total of 50 years. A system using one or two stages of nuclear electric propulsion (NEP) was selected as a possible baseline. The most promising alternatives are ultralight solar sails or laser sailing, with the lasers in earth orbit, for example. The NEP baseline design allows the option of carrying a Pluto orbiter as a daughter spacecraft.

  11. PRECURSOR FLARES IN OJ 287

    SciTech Connect

    Pihajoki, P.; Berdyugin, A.; Lindfors, E.; Reinthal, R.; Sillanpaeae, A.; Takalo, L.; Valtonen, M.; Nilsson, K.; Zola, S.; Koziel-Wierzbowska, D.; Liakos, A.; Drozdz, M.; Winiarski, M.; Ogloza, W.; Provencal, J.; Santangelo, M. M. M.; Salo, H.; Chandra, S.; Ganesh, S.; Baliyan, K. S.; and others

    2013-02-10

    We have studied three most recent precursor flares in the light curve of the blazar OJ 287 while invoking the presence of a precessing binary black hole in the system to explain the nature of these flares. Precursor flare timings from the historical light curves are compared with theoretical predictions from our model that incorporate effects of an accretion disk and post-Newtonian description for the binary black hole orbit. We find that the precursor flares coincide with the secondary black hole descending toward the accretion disk of the primary black hole from the observed side, with a mean z-component of approximately z{sub c} = 4000 AU. We use this model of precursor flares to predict that precursor flare of similar nature should happen around 2020.96 before the next major outburst in 2022.

  12. Three novel antimicrobial peptides from the skin of the Indian bronzed frog Hylarana temporalis (Anura: Ranidae).

    PubMed

    Reshmy, V; Preeji, V; Parvin, A; Santhoshkumar, K; George, S

    2011-05-01

    Amphibian skin secretion is considered as a rich source of bioactive peptides. The present work describes the successful identification of three novel peptides named brevinin-1TEa, brevinin-2TEa and brevinin-2TEb present in the skin secretion of Indian bronzed frog Hylarana temporalis. The deduced open reading frame encoding the biosynthetic precursor of brevinin-1TEa consisted of 70 amino acid residues and brevinin-2TEa and brevinin-2TEb consisted of 71 and 72 amino acids, respectively. All the three peptides showed higher antimicrobial activity against Gram-negative than against Gram-positive bacteria. On the basis of the antibacterial and haemolytic activity, brevinin-2TEb is the most potent peptide reported in the present study. Further research on these peptides may provide potential clue towards newer drug development to combat various microbial diseases.

  13. Preparation of superconductor precursor powders

    DOEpatents

    Bhattacharya, Raghunath

    1998-01-01

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic and/or reduced particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of all metals in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products.

  14. Brillouin precursors in Debye media

    NASA Astrophysics Data System (ADS)

    Macke, Bruno; Ségard, Bernard

    2015-05-01

    We theoretically study the formation of Brillouin precursors in Debye media. We point out that the precursors are visible only at propagation distances such that the impulse response of the medium is essentially determined by the frequency dependence of its absorption and is practically Gaussian. By simple convolution, we then obtain explicit analytical expressions of the transmitted waves generated by reference incident waves, distinguishing precursor and main signal by a simple examination of the long-time behavior of the overall signal. These expressions are in good agreement with the signals obtained in numerical or real experiments performed on water in the radio-frequency domain and explain in particular some observed shapes of the precursor. Results are obtained for other remarkable incident waves. In addition, we show quite generally that the shape of the Brillouin precursor appearing alone at sufficiently large propagation distance and the law giving its amplitude as a function of this distance do not depend on the precise form of the incident wave but only on its integral properties. The incidence of a static conductivity of the medium is also examined and explicit analytical results are again given in the limit of weak and strong conductivities.

  15. Preparation of superconductor precursor powders

    DOEpatents

    Bhattacharya, R.

    1998-08-04

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic and/or reduced particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of all metals in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products. 7 figs.

  16. Preparation of superconductor precursor powders

    DOEpatents

    Bhattacharya, Raghunath; Blaugher, Richard D.

    1995-01-01

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals, such as nitrate salts of thallium, barium, calcium, and copper, which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of thallium in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products.

  17. Processing of a plant vacuolar protein precursor in vitro.

    PubMed

    Hattori, T; Ichihara, S; Nakamura, K

    1987-08-01

    A precursor for sporamin A, the storage protein of the tuberous roots of sweet potato deposited in the vacuole, is synthesized on membrane-bound polysomes and has an extra peptide of 37 amino acids at the N-terminus of the mature form, which can be divided into an N-terminal putative signal peptide sequence (residues -37 to -17) and a segment enriched with charged amino acids (residues -16 to -1) [Hattori, T., et al. (1985) Plant Mol. Biol. 5, 313-320]. We examined the in vitro processing of the sporamin A precursor using a messenger RNA derived from a full-length cDNA by the SP6 transcription system. When the in vitro translation in a wheat germ cell-free system was carried out in the presence of dog pancreas microsomal membranes, the precursor polypeptide (Mr = 24,000) was processed into an intermediate form still larger than the mature polypeptide (Mr = 20,000). The processed intermediate form was also produced by addition of microsomal membranes from sweet potato and potato in the translation reaction, although less efficiently compared to dog membranes. Moreover, Escherichia coli cells expressing sporamin precursor accumulated a polypeptide with the same electrophoretic mobility as the intermediate form produced in vitro. The processing by dog membranes is accompanied by translocation of the polypeptide across the membranes as assayed by resistance to externally added proteases. The N-terminal amino acid sequencing analysis of [3H]leucine-labelled intermediate form produced in vitro by dog membranes indicated that co-translational processing of the sporamin precursor by endoplasmic reticulum membranes removes only the signal peptide segment from the extra peptide, and suggested that the charged segment following the signal peptide is removed post-translationally during the transport of sporamin into vacuole. The significance of two-step processing of plant vacuolar protein precursor is discussed in relation to the two-step processing of precursors for yeast

  18. Particulate and THM precursor removal with ferric chloride

    SciTech Connect

    Childress, A.E.; Vrijenhoek, E.M.; Elimelech, M.; Tanaka, T.S.; Beuhler, M.D.

    1999-11-01

    Pilot-scale experiments were performed to investigate the effectiveness of enhanced coagulation in removing particles and trihalomethane (THM) precursors from two surface source waters: California State Project water and Colorado River water. The removal of suspended particles and natural organic matter at various ferric chloride doses and coagulation pHs was assessed through source water and filter effluent measurements of turbidity, particle count. UV{sub 254}, TOC, and THM formation potential. Overall, it was found that optimal removal of particles and THM precursors by enhanced coagulation with ferric chloride is obtained at high coagulant doses and low pH conditions. Generally, turbidity removal is more efficient and head loss is more moderate at ambient pH compared with pH 5.5. Additionally, filter effluent particle counts were found to be consistent with residual turbidity data. The removal of THM precursors by enhanced coagulation is significantly enhanced at pH 5.5 compared with ambient pH. The reduction in THM formation potential is consistent with the trends observed for the THM precursor removal data. Furthermore, specific UV absorbance was used to estimate the proportion of humic substances in the raw waters. Enhanced coagulation was found to be less effective for the source water with the lower specific UV absorbance.

  19. Complete Assignment of (1)H-NMR Resonances of the King Cobra Neurotoxin CM-11.

    PubMed

    Pang, Yu-Xi; Liu, Wei-Dong; Liu, Ai-Zhuo; Pei, Feng-Kui

    1997-01-01

    The king cobra (Ophiophagus Hannah) neurotoxin CM-Il is long-chain peptide with 72 amino acid residues. Its complete assignment of (1)H-NMR resonances was obtained using various 2D-NMR technologies, including DQF-COSY, clean-TOCSY and NOESY.

  20. Precursor polymer compositions comprising polybenzimidazole

    SciTech Connect

    Klaehn, John R.; Peterson, Eric S.; Orme, Christopher J.

    2015-07-14

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  1. The Innate Lymphoid Cell Precursor.

    PubMed

    Ishizuka, Isabel E; Constantinides, Michael G; Gudjonson, Herman; Bendelac, Albert

    2016-05-20

    The discovery of tissue-resident innate lymphoid cell populations effecting different forms of type 1, 2, and 3 immunity; tissue repair; and immune regulation has transformed our understanding of mucosal immunity and allergy. The emerging complexity of these populations along with compounding issues of redundancy and plasticity raise intriguing questions about their precise lineage relationship. Here we review advances in mapping the emergence of these lineages from early lymphoid precursors. We discuss the identification of a common innate lymphoid cell precursor characterized by transient expression of the transcription factor PLZF, and the lineage relationships of innate lymphoid cells with conventional natural killer cells and lymphoid tissue inducer cells. We also review the rapidly growing understanding of the network of transcription factors that direct the development of these lineages.

  2. Neurotransmitter precursors and brain function.

    PubMed

    Conlay, L A; Zeisel, S H

    1982-04-01

    Brain function can be affected by the availability of dietary precursors of neurotransmitters. This occurs because the rate-limiting synthetic enzymes are not "saturated" with substrate under normal circumstances. Tyrosine affects catecholaminergic neurons that fire rapidly, whether in the brain stem to decrease blood pressure in hypertension or in the adrenal gland to increase blood pressure in hypotension, and has been used in the treatment of Parkinson's disease and depression. Choline forms acetylcholine and has been used successfully in the treatment of tardive dyskinesia and memory disorders. Tryptophan, which forms serotonin, has been used for chronic pain therapy, sleep disorders, depression, and appetite control. Although these substances may lack the potency of traditionally used agonists, they offer an increase in specificity because the enzymes necessary to convert them to neurotransmitters are found only in neurons. Precursors are also "physiological"; they are consumed as foods and, therefore, should be relatively safe therapeutic agents. PMID:6124895

  3. Precursors of Short Gamma-Ray Bursts

    NASA Technical Reports Server (NTRS)

    Troja, E.; Rosswog, S.; Gehrels, N.

    2010-01-01

    We carried out a systematic search of precursors on the sample of short GRBs observed by Swift. We found that approx. 8-10% of short GRBs display such early episode of emission. One burst (GRB 090510) shows two precursor events, the former approx.13 s and the latter approx. 0.5 s before the GRB. We did not find any substantial difference between the precursor and the main GRB emission, and between short GRBs with and without precursors. We discuss possible mechanisms to reproduce the observed precursor emission within the scenario of compact object mergers. The implications of our results on quantum gravity constraints are also discussed.

  4. Precursor Lesions of Pancreatic Cancer

    PubMed Central

    Higashi, Michiyo; Yamada, Norishige; Goto, Masamichi

    2008-01-01

    This review article describes morphological aspects, gene abnormalities, and mucin expression profiles in precursor lesions such as pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasm (IPMN), and mucinous cystic neoplasm (MCN) of the pancreas, as well as their relation to pancreatic ductal adenocarcinoma (PDAC). The gene abnormalities in precursors of PDAC are summarized as follows: (1) KRAS mutation and p16/CDKN2A inactivation are early events whose frequencies increase with the dysplasia grade in both PanIN and IPMN; (2) TP53 mutation and SMAD4/DPC4 inactivation are late events observed in PanIN3 or carcinomatous change of IPMN in both PanIN and IPMN, although the frequency of the TP53 mutation is lower in IPMN than in PDAC; and (3) also in MCN, KRAS mutation is an early event whose frequency increases with the dysplasia grade, whereas TP53 mutation and SMAD4/DPC4 inactivation are evident only in the carcinoma. The mucin expression profiles in precursors of PDAC are summarized as follows: (1) MUC1 expression increases with the PanIN grade, and is high in PDAC; (2) the expression pattern of MUC2 differs markedly between the major subtypes of IPMN with different malignancy potentials (i.e., IPMN-intestinal type with MUC2+ expression and IPMN-gastric type with MUC2- expression); (3) MUC2 is not expressed in any grade of PanINs, which is useful for differentiating PanIN from intestinal-type IPMN; (4) de novo expression of MUC4, which appears to increase with the dysplasia grade; and (5) high de novo expression of MUC5AC in all grades of PanINs, all types of IPMN, MCN, and PDAC. PMID:20485640

  5. Regression analysis of reported earthquake precursors. I. Presentation of data

    NASA Astrophysics Data System (ADS)

    Niazi, Mansour

    1984-11-01

    Around 700 reported precursors of about 350 earthquakes, including the negative observations, have been compiled in 11 categories with 31 subdivisions. The data base is subjected to an initial sorting and screening by imposing three restrictions on the ranges of main shock magnitude ( M≥4.0), precursory time ( t≤20 years), and the epicentral distance of observation points ( X m≤4.100.3 M ). Of the 31 subcategories of precursory phenomena, 18 with 9 data points or more are independently studied by regressing their precursory times against magnitude. The preliminary results tend to classify the precursors into three groups: 1. The precursors which show weak or no correlation between time and the magnitude of the eventual main shock. Examples of this group are foreshocks and precursory tilt. 2. The precursors which show clear scaling with magnitude. These include seismic velocity ratio ( V p/Vs), travel time delay, duration of seismic quiescence, and, to some degree, the variation of b-value, and anomalous seismicity. 3. The precursors which display clustering of precursory times around a mean value, which differs for different precursors from a few hours to a few years. Examples include the conductivity rate, geoelectric current and potential, strain, water well level, geochemical anomalies, change of focal mechanism, and the enhancement of seismicity reported only for larger earthquakes. Some of the precursors in this category, such as leveling changes and the occurrence of microseismicity, show bimodal patterns of precursory times and may partially be coseismic. In addition, each category with a sufficient number of reported estimates of distance and signal amplitude is subjected to multiple linear regression. The usefulness of these regressions at this stage appears to be limited to specifying which of the parameters shows a more significant correlation. Standard deviations of residuals of precursory time against magnitude are generally reduced when

  6. The synergy of earthquake precursors

    NASA Astrophysics Data System (ADS)

    Pulinets, Sergey

    2011-12-01

    The system of geophysical shells (lithosphere, atmosphere, ionosphere) is considered as an open complex nonlinear system with dissipation where earthquake preparation could be regarded as a self-organizing process leading to the critical state of the system. The processes in atmosphere and ionosphere are considered from the point of view of non-equilibrium thermodynamics. The intensive ionization of boundary layer of atmosphere (probably provided by radon in occasion of earthquake preparation) gives start to the synergetic sequence of coupling processes where the ionosphere and even magnetosphere are the last links in the chain of interactions. Every anomaly observed in different geophysical fields (surface temperature, latent heat flux, electromagnetic emissions, variations in ionosphere, particle precipitation, etc.) is not considered as an individual process but the part of the self-organizing process, the final goal of which is the reaching of the point of the maximum entropy. Radon anomaly before the Kobe earthquake is considered as a perfect example to satisfy the formal seismological determination of the earthquake precursor. What is genetically connected with radon through the ionization process can also be regarded as a precursor. The problem of co-seismic variations of the discussed parameters of atmosphere and ionosphere is considered as well.

  7. Annealing of aromatic polyimide precursors

    NASA Technical Reports Server (NTRS)

    Wakelyn, N. T.

    1975-01-01

    A study has been made of the thermal behavior of polyimide precursors: an isomeric pair of crystals of the complex formed by p-phenylenediamine with the separated isomers of the di-isopropyl ester of pyromellitic acid. Specimens of this material were isothermally annealed in the temperature range 120 C to 170 C for periods of time up to 1 week. Although this temperature range is well below that customarily used for imidizations, the working hypothesis was that it would be more likely that a polymer embodying at least part of the precursor structure could be formed if the molecular motion was minimized to that actually required for the formation of the imide linkage. The progress of the annealing was followed by: infrared spectroscopy, differential thermal analysis, powder X-ray diffraction, and thermal gravimetric analysis. Single crystal X-ray analysis of the meta monomer yields a structure of chains of alternating acid and base and suggests that this monomer is amenable to polymerization with a minimum of geometrical disruption.

  8. Precursor protein of Alzheimer's disease A4 amyloid is encoded by 16 exons

    SciTech Connect

    Lemaire, H.G.; Kang, J.; Mueller-Hill, B. ); Salbaum, J.M.; Multhaup, G.; Beyreuther, K. ); Bayney, R.M.; Unterbeck, A. )

    1989-01-25

    Alzheimer's disease (AD) is characterized by the cerebral deposition of fibrillar aggregates of the amyloid A4 protein. Complementary DNA's coding for the precursor of the amyloid A4 protein have been described. In order to identify the structure of the precursor gene relevant clones from several human genomic libraries were isolated. Sequence analysis of the various clones revealed 16 exons to encode the 695 residue precursor protein (PreA4{sub 695}) of Alzheimer's disease amyloid A4 protein. The DNA sequence coding for the amyloid A4 protein is interrupted by an intron. This finding supports the idea that amyloid A4 protein arises by incomplete proteolysis of a larger precursor, and not by aberrant splicing.

  9. Cloning and sequence analysis of cDNA encoding urotensin I precursor.

    PubMed Central

    Ishida, I; Ichikawa, T; Deguchi, T

    1986-01-01

    The primary structure of the precursor of urotensin I, a neuropeptide hormone from the caudal neurosecretory system of the carp Cyprinus carpio, has been determined by analyzing the nucleotide sequence of cloned DNA complementary to the mRNA encoding it. The precursor consists of 145 amino acid residues and the carboxyl terminus represents the 41-amino acid sequence of urotensin I, preceded by Lys-Arg and followed by Gly-Lys. Sequence homology as well as similar organization of the precursors of urotensin I and mammalian corticotropin-releasing factors suggest that they are evolutionarily related. RNA transfer blot analysis indicates that mRNA encoding the precursor of urotensin I is present only in the spinal cord and not in the brain, intestine, liver, or kidney of the carp. Images PMID:3484550

  10. Precursor De13.1 from Conus delessertii defines the novel G gene superfamily.

    PubMed

    Aguilar, Manuel B; Ortiz, Ernesto; Kaas, Quentin; López-Vera, Estuardo; Becerril, Baltazar; Possani, Lourival D; de la Cotera, Edgar P Heimer

    2013-03-01

    Peptide de13a was previously purified from the venom of the worm-hunting cone snail Conus delessertii from the Yucatán Channel, México. This peptide has eight cysteine (Cys) residues in the unique arrangement C-C-C-CC-C-C-C, which defines the cysteine framework XIII ("-" represents one or more non-Cys residues). Remarkably, δ-hydroxy-lysine residues have been found only in conotoxin de13a, which also contains an unusually high proportion of hydroxylated amino acid residues. Here, we report the cDNA cloning of the complete precursor De13.1 of a related peptide, de13b, which has the same Cys framework and inter-Cys spacings as peptide de13a, and shares high protein/nucleic acid sequence identity (87%/90%) with de13a, suggesting that both peptides belong to the same conotoxin gene superfamily. Analysis of the signal peptide of precursor De13.1 reveals that this precursor belongs to a novel conotoxin gene superfamily that we chose to name gene superfamily G. Thus far superfamily G only includes two peptides, each of which contains the same, distinctive Cys framework and a high proportion of amino acid residues with hydroxylated side chains. PMID:23340018

  11. Engineering the Microstructure of Solution Precursor Plasma-Sprayed Coatings

    NASA Astrophysics Data System (ADS)

    Bertolissi, G.; Chazelas, C.; Bolelli, G.; Lusvarghi, L.; Vardelle, M.; Vardelle, A.

    2012-12-01

    This study examines the fundamental reactions that occur in-flight during the solution precursor plasma spraying (SPPS) of solutions containing Zr- and Y-based salts in water or ethanol solvent. The effect of plasma jet composition (pure Ar, Ar-H2 and Ar-He-H2 mixtures) on the mechanical break-up and thermal treatment of the solution, mechanically injected in the form of a liquid stream, was investigated. Observation of the size evolution of the solution droplets in the plasma flow by means of a laser shadowgraphy technique, showed that droplet break-up was more effective and solvent evaporation was faster when the ethanol-based solution was injected into binary or ternary plasma gas mixtures. In contrast with water-based solutions, residual liquid droplets were always detected at the substrate location. The morphology and structure of the material deposited onto stainless steel substrates during single-scan experiments were characterised by SEM, XRD and micro-Raman spectroscopy and were shown to be closely related to in-flight droplet behaviour. In-flight pyrolysis and melting of the precursor led to well-flattened splats, whereas residual liquid droplets at the substrate location turned into non pyrolysed inclusions. The latter, although subsequently pyrolysed by the plasma heat during the deposition of entire coatings, resulted in porous "sponge-like" structures in the deposit.

  12. Precursors for Carbon Nitride Synthesis

    SciTech Connect

    Prashantha, M.; Gopal, E. S. R.; Ramesh, K.

    2011-07-15

    Nano structured carbon nitride films were prepared by pyrolysis assisted chemical vapour deposition. Pyrrole (C{sub 4}H{sub 5}N), Pyrrolidine (C{sub 4}H{sub 9}N), Azabenzimidazole (C{sub 6}H{sub 5}N{sub 3}) and Triazine (C{sub 6}H{sub 15}N{sub 3}) were used as precursors. The vibrational modes observed for C-N and C = N from FTIR spectra confirms the bonding of nitrogen with carbon. XPS core level spectra of C 1s and N 1s also show the formation of bonding between carbon and nitrogen atoms. The nitrogen content in the prepared samples was found to be around 25 atomic %.

  13. Functional analyses and treatment of precursor behavior.

    PubMed

    Najdowski, Adel C; Wallace, Michele D; Ellsworth, Carrie L; MacAleese, Alicia N; Cleveland, Jackie M

    2008-01-01

    Functional analysis has been demonstrated to be an effective method to identify environmental variables that maintain problem behavior. However, there are cases when conducting functional analyses of severe problem behavior may be contraindicated. The current study applied functional analysis procedures to a class of behavior that preceded severe problem behavior (precursor behavior) and evaluated treatments based on the outcomes of the functional analyses of precursor behavior. Responding for all participants was differentiated during the functional analyses, and individualized treatments eliminated precursor behavior. These results suggest that functional analysis of precursor behavior may offer an alternative, indirect method to assess the operant function of severe problem behavior. PMID:18468282

  14. Functional Analyses and Treatment of Precursor Behavior

    PubMed Central

    Najdowski, Adel C; Wallace, Michele D; Ellsworth, Carrie L; MacAleese, Alicia N; Cleveland, Jackie M

    2008-01-01

    Functional analysis has been demonstrated to be an effective method to identify environmental variables that maintain problem behavior. However, there are cases when conducting functional analyses of severe problem behavior may be contraindicated. The current study applied functional analysis procedures to a class of behavior that preceded severe problem behavior (precursor behavior) and evaluated treatments based on the outcomes of the functional analyses of precursor behavior. Responding for all participants was differentiated during the functional analyses, and individualized treatments eliminated precursor behavior. These results suggest that functional analysis of precursor behavior may offer an alternative, indirect method to assess the operant function of severe problem behavior. PMID:18468282

  15. Biodegradation and biotransformation of wastewater organics as precursors of disinfection byproducts in water.

    PubMed

    Liu, Jin-lin; Li, Xiao-yan

    2010-11-01

    Laboratory experiments were carried out to investigate wastewater organics as the precursors of disinfection byproducts (DBPs) in drinking water supply. The focus was on the change in wastewater DBP precursors during biological degradation under simulated natural conditions. The wastewater and its treated secondary effluent were characterized for DBP formation potential (DBPFP) and DBP speciation profile, including trihalomethanes, haloacetic acids, chloral hydrate, and nitrogen-containing DBPs. Several model organic compounds, including humic acid, tannic acid, glucose, starch, glycine, and bovine serum albumin (BSA), were used to represent the different types of organic pollutants in wastewater discharge. The results show that the DBPFP of wastewater decreased after biodegradation, but the remaining organic matter had a greater DBPFP yield with chlorine. Different model organics displayed different changes in DBPFP during biodegradation. The DBPFP remained largely unchanged for the glycine solution, decreased greatly for the tannic acid and BSA solutions, and increased nearly 3-fold for the glucose and starch solutions after 10d of biodegradation. Meanwhile, the DBPFP yield increased from 3 for glycine to 51μg DBP mg(-1) C for its degradation residue, and from 1 for glucose and starch to 87 and 38μg DBP mg(-1) C for their organic residues, respectively. Although biodegradation may effectively remove some DBP precursors, biotransformation during the process produces new DBP precursors in the form of soluble microbial products (SMPs). The experimental results reveal that SMPs may be an important source of wastewater-derived DBP precursors in natural waters.

  16. Leading time domain seismic precursors

    NASA Astrophysics Data System (ADS)

    Boucouvalas, A. C.; Gkasios, M.; Keskebes, A.; Tselikas, N. T.

    2014-08-01

    The problem of predicting the occurrence of earthquakes is threefold. On one hand it is necessary to predict the date and magnitude of an earthquake, and on the other hand the location of the epicenter. In this work after a brief review of the state of earthquake prediction research, we report on a new leading time precursor for determining time onset of earthquake occurrence. We report the linking between earthquakes of the past with those which happen in the future via Fibonacci, Dual and Lucas numbers (FDL) numbers. We demonstrate it here with two example seed earthquakes at least 100 years old. Using this leading indicator method we can predict significant earthquake events >6.5R, with good accuracy approximately +- 1 day somewhere in the world. From a single seed we produce at least 100 trials simultaneously of which 50% are correct to +- 1day. The indicator is based on Fibonacci, Dual and Lucas numbers (FDL). This result hints that the log periodic FDL numbers are at the root of the understanding of the earthquake mechanism. The theory is based on the assumption that each occurred earthquake discontinuity can be thought of as a generating source of FDL time series. (The mechanism could well be linked to planetary orbits). When future dates are derived from clustering and convergence from previous strong earthquake dates at an FDL time distance, then we have a high probability for an earthquake to occur on that date. We set up a real time system which generates FDL time series from each previous significant earthquake (>7R) and we produce a year to year calendar of high probability earthquake dates. We have tested this over a number of years with considerable success. We have applied this technique for strong (>7R) earthquakes across the globe as well as on a restricted region such as the Greek geographic region where the magnitude is small (>4R-6.5R). In both cases the success of the method is impressive. It is our belief that supplementing this method with

  17. Effect of detergents on streptolysin S precursor.

    PubMed

    Calandra, G B

    1980-08-01

    Group A streptococci which produce streptolysin S contain a cellular precursor to streptolysin S in the membranes and cytoplasm which is activatable by blending in a Vortex mixer with glass beads and ribonucleic acid (RNA)-core (RNA preparation from yeast). Although no activation of precursor occurred when it was mixed with detergents, it was activated when blended with glass beads and detergents such as Tergitol NP-40 and Brij 35. Maximum activation of precursor was achieved in 1 to 2% detergent, in pH 6.5 buffer, and after 8 min of blending. Detergents Tween 20, 40, 60, and 80, Brij 56, and Lubrol WX also activated precursor, but, of all the hemolysin preparations, those with Tween 40 or 60 or Lubrol WX were the most stable. The addition of RNA-core during or after blending of precursor with detergents enhanced the titer and stability of the hemolysin. This was due in part to the association of the hemolytic moiety with RNA-core. Activation of precursor in the membrane was better with a detergent, whereas that in the cytoplasm was better with RNA-core. Therefore, precursor from two different cellular locations can be differentiated by the effects of RNA-core and detergents on precursor titer.

  18. Precursors in gas-liquid mixtures

    NASA Astrophysics Data System (ADS)

    Gasenko, V. G.; Gorelik, R. S.; Nakoryakov, V. E.; Timkin, L. S.

    2013-10-01

    Two types of precursors propagating at the speed of sound in a pure liquid have been revealed in the experiments on the evolution of pressure pulses in a gas-liquid mixture; at the same time, the main pressure pulse propagates at a low equilibrium speed of sound and its evolution is described by the Burgers-Korteweg-de Vries equation. The first high-frequency precursor is a complete analog of a classical Sommerfeld precursor, because the resonance dispersion equation for a bubble mixture coincides with that for insulators in the Lorentz model, and oscillates at a frequency close to the "plasma frequency." The second low-frequency precursor has been revealed in this work. The frequency of the low-frequency precursor is close to the resonance frequency of pulsations of bubbles, which is almost an order of magnitude lower than the frequency of the high-frequency precursor. The low-frequency precursor has a much larger amplitude of pulsations and smaller damping and is not described within the homogeneous model of the gas-liquid mixture. The observed phenomenon of low-frequency precursors has been explained within a simple heterogeneous model of a bubble liquid.

  19. The Interrelationships of Mathematical Precursors in Kindergarten

    ERIC Educational Resources Information Center

    Cirino, Paul T.

    2011-01-01

    This study evaluated the interrelations among cognitive precursors across quantitative, linguistic, and spatial attention domains that have been implicated for math achievement in young children. The dimensionality of the quantity precursors was evaluated in 286 kindergarteners via latent variable techniques, and the contribution of precursors…

  20. Method of texturing a superconductive oxide precursor

    DOEpatents

    DeMoranville, Kenneth L.; Li, Qi; Antaya, Peter D.; Christopherson, Craig J.; Riley, Jr., Gilbert N.; Seuntjens, Jeffrey M.

    1999-01-01

    A method of forming a textured superconductor wire includes constraining an elongated superconductor precursor between two constraining elongated members placed in contact therewith on opposite sides of the superconductor precursor, and passing the superconductor precursor with the two constraining members through flat rolls to form the textured superconductor wire. The method includes selecting desired cross-sectional shape and size constraining members to control the width of the formed superconductor wire. A textured superconductor wire formed by the method of the invention has regular-shaped, curved sides and is free of flashing. A rolling assembly for single-pass rolling of the elongated precursor superconductor includes two rolls, two constraining members, and a fixture for feeding the precursor superconductor and the constraining members between the rolls. In alternate embodiments of the invention, the rolls can have machined regions which will contact only the elongated constraining members and affect the lateral deformation and movement of those members during the rolling process.

  1. A thermal and chemical degradation approach to decipher pristane and phytane precursors in sedimentary organic matter

    USGS Publications Warehouse

    Koopmans, M.P.; Rijpstra, W.I.C.; Klapwijk, M.M.; De Leeuw, J. W.; Lewan, M.D.; Sinninghe, Damste J.S.

    1999-01-01

    A thermal and chemical degradation approach was followed to determine the precursors of pristane (Pr) and phytane (Ph) in samples from the Gessoso-solfifera, Ghareb and Green River Formations. Hydrous pyrolysis of these samples yields large amounts of Pr and Ph carbon skeletons, indicating that their precursors are predominantly sequestered in high-molecular-weight fractions. However, chemical degradation of the polar fraction and the kerogen of the unheated samples generally does not release large amounts of Pr and Ph. Additional information on the precursors of Pr and Ph is obtained from flash pyrolysis analyses of kerogens and residues after hydrous pyrolysis and after chemical degradation. Multiple precursors for Pr and Ph are recognised in these three samples. The main increase of the Pr/Ph ratio with increasing maturation temperature, which is associated with strongly increasing amounts of Pr and Ph, is probably due to the higher amount of precursors of Pr compared to Ph, and not to the different timing of generation of Pr and Ph.A thermal and chemical degradation approach was followed to determine the precursors of pristane (Pr) and phytane (Ph) in samples from the Gessoso-solfifera, Ghareb and Green River Formations. Hydrous pyrolysis of these samples yields large amounts of Pr and Ph carbon skeletons, indicating that their precursors are predominantly sequestered in high-molecular-weight fractions. However, chemical degradation of the polar fraction and the kerogen of the unheated samples generally does not release large amounts of Pr and Ph. Additional information on the precursors of Pr and Ph is obtained from flash pyrolysis analyses of kerogens and residues after hydrous pyrolysis and after chemical degradation. Multiple precursors for Pr and Ph are recognised in these three samples. The main increase of the Pr/Ph ratio with increasing maturation temperature, which is associated with strongly increasing amounts of Pr and Ph, is probably due to the

  2. Yeast secretory expression of insulin precursors.

    PubMed

    Kjeldsen, T

    2000-09-01

    Since the 1980s, recombinant human insulin for the treatment of diabetes mellitus has been produced using either the yeast Saccharomyces cerevisiae or the prokaryote Escherichia coli. Here, development of the insulin secretory expression system in S. cerevisiae and its subsequent optimisation is described. Expression of proinsulin in S. cerevisiae does not result in efficient secretion of proinsulin or insulin. However, expression of a cDNA encoding a proinsulin-like molecule with deletion of threonine(B30) as a fusion protein with the S. cerevisiae alpha-factor prepro-peptide (leader), followed either by replacement of the human proinsulin C-peptide with a small C-peptide (e.g. AAK), or by direct fusion of lysine(B29) to glycine(A1), results in the efficient secretion of folded single-chain proinsulin-like molecules to the culture supernatant. The secreted single-chain insulin precursor can then be purified and subsequently converted to human insulin by tryptic transpeptidation in organic aqueous medium in the presence of a threonine ester. The leader confers secretory competence to the insulin precursor, and constructed (synthetic) leaders have been developed for efficient secretory expression of the insulin precursor in the yeasts S. cerevisiae and Pichia pastories. The Kex2 endoprotease, specific for dibasic sites, cleaves the leader-insulin precursor fusion protein in the late secretory pathway and the folded insulin precursor is secreted to the culture supernatant. However, the Kex2 endoprotease processing of the pro-peptide-insulin precursor fusion protein is incomplete and a significant part of the pro-peptide-insulin precursor fusion protein is secreted to the culture supernatant in a hyperglycosylated form. A spacer peptide localised between the leader and the insulin precursor has been developed to optimise Kex2 endoprotease processing and insulin precursor fermentation yield. PMID:11030562

  3. Atomic Layer Deposition from Dissolved Precursors.

    PubMed

    Wu, Yanlin; Döhler, Dirk; Barr, Maïssa; Oks, Elina; Wolf, Marc; Santinacci, Lionel; Bachmann, Julien

    2015-10-14

    We establish a novel thin film deposition technique by transferring the principles of atomic layer deposition (ALD) known with gaseous precursors toward precursors dissolved in a liquid. An established ALD reaction behaves similarly when performed from solutions. "Solution ALD" (sALD) can coat deep pores in a conformal manner. sALD offers novel opportunities by overcoming the need for volatile and thermally robust precursors. We establish a MgO sALD procedure based on the hydrolysis of a Grignard reagent.

  4. Synthesis and structures of metal chalcogenide precursors

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; Duraj, Stan A.; Eckles, William E.; Andras, Maria T.

    1990-01-01

    The reactivity of early transition metal sandwich complexes with sulfur-rich molecules such as dithiocarboxylic acids was studied. Researchers recently initiated work on precursors to CuInSe2 and related chalcopyrite semiconductors. Th every high radiation tolerance and the high absorption coefficient of CuInSe2 makes this material extremely attractive for lightweight space solar cells. Their general approach in early transition metal chemistry, the reaction of low-valent metal complexes or metal powders with sulfur and selenium rich compounds, was extended to the synthesis of chalcopyrite precursors. Here, the researchers describe synthesis, structures, and and routes to single molecule precursors to metal chalcogenides.

  5. Evolution of S-cysteinylated and S-glutathionylated thiol precursors during oxidation of Melon B. and Sauvignon blanc musts.

    PubMed

    Roland, Aurélie; Vialaret, Jérôme; Razungles, Alain; Rigou, Peggy; Schneider, Rémi

    2010-04-14

    Thiol precursor content in Melon B. and Sauvignon blanc grape juices obtained under vacuum was determined by quantifying cysteinylated and glutathionylated conjugates of 3-mercaptohexan-1-ol (3MH) and 4-methyl-4-mercaptopentan-2-one (4MMP). This characterization allowed the study of thiol precursor evolution during ripening of Sauvignon blanc grapes in several viticultural situations together with grape reaction product (GRP) and the main substrate of polyphenoloxidase, that is, caftaric acid. Concentration of precursors greatly increased during ripening except for the cysteinylated conjugate of 4MMP. Precursor evolution was also monitored during the oxidation of grape juice. Addition of oxygen to a grape juice set off the enzymatic oxidation of hydroxycinnamic acids but did not negatively affect precursor concentrations. Part of the glutathionylated precursor of the 3MH was produced during prefermentative operations (up to 140% in Sauvignon blanc). Consequently, this precursor naturally occurring in grapes was also formed during prefermentative operations. The proportion of biogenetic and prefermentary formation of the glutathionylated precursor of 3MH was different under industrial conditions depending on the grape variety considered. Addition of glutathione and hexenal in grape juices of Melon B. and Sauvignon induced an increase of the production of 3MH and consequently of its acetate in the resulting wines. Residual glutathione in must has to be preserved to enhance the aromatic potential of grapes. PMID:20199086

  6. Pesticide residues in eagles

    USGS Publications Warehouse

    Reichel, W.L.; Cromartie, E.; Lamont, T.G.; Mulhern, B.M.; Prouty, R.M.

    1969-01-01

    Bald and golden eagles found sick or dead in 18 States and Canada during 1964-1965 were analyzed for pesticide residues. Residues in bald eagles were considerably higher than in golden eagles. Residues of DDE, DDD, and dieldrin were detected in all samples of bald eagle carcasses; other compounds found, less frequently were heptachlor epoxide, endrin, and DCBP, a metabolite of DDT. DDE was detected in all samples of golden eagle carcasses; DDD, DDT, dieldrin, and heptachlor epoxide were detected less frequently.

  7. Structural Basis For Antigenic Peptide Precursor Processing by the Endoplasmic Reticulum Aminopeptidase ERAP1

    SciTech Connect

    T Nguyen; S Chang; I Evnouchidou; I York; C Zikos; K Rock; A Goldberg; E Stratikos; L Stern

    2011-12-31

    ERAP1 trims antigen precursors to fit into MHC class I proteins. To fulfill this function, ERAP1 has unique substrate preferences, trimming long peptides but sparing shorter ones. To identify the structural basis for ERAP1's unusual properties, we determined the X-ray crystal structure of human ERAP1 bound to bestatin. The structure reveals an open conformation with a large interior compartment. An extended groove originating from the enzyme's catalytic center can accommodate long peptides and has features that explain ERAP1's broad specificity for antigenic peptide precursors. Structural and biochemical analyses suggest a mechanism for ERAP1's length-dependent trimming activity, whereby binding of long rather than short substrates induces a conformational change with reorientation of a key catalytic residue toward the active site. ERAP1's unique structural elements suggest how a generic aminopeptidase structure has been adapted for the specialized function of trimming antigenic precursors.

  8. Characterization of the early steps of OE17 precursor transport by the thylakoid DeltapH/Tat machinery.

    PubMed

    Musser, S M; Theg, S M

    2000-05-01

    In order to probe the structure and protein translocation function of the thylakoid Tat machinery, a 25-residue C-terminal extension containing a 13-residue in vivo biotinylation tag and a 6x His tag was added to a mutant precursor of the 17-kDa subunit of the oxygen-evolving complex to form pOE17(C)-BioHis. When avidin was attached to biotinylated precursor in situ, the precursor-avidin complex was neither imported nor did it form a membrane-spanning translocation intermediate. It did, however, competitively inhibit the translocation of unbiotinylated precursor with an apparent KI unaffected by avidin. It is shown that the precursor protein achieves a stable folded structure upon dilution from urea, suggesting that the avidin-induced inhibition of transport results from a folding-induced proximity of N-terminal and C-terminal domains. It is further demonstrated that the majority of precursor rapidly binds to the thylakoid membrane, remaining import competent and yet undissociable by high salt or high pH treatment at ice temperature. The membrane binding event is unaffected by avidin. Import kinetics reveal that nonproton motive force-driven transport steps make up a major fraction of the transport time. These observations suggest that the N-terminal presequence on the avidin-bound precursor is available for membrane binding and initial recognition by the transport machinery, but the attached avidin signals the machinery that the precursor is an incorrectly configured substrate and thus import is aborted. Consequently, the DeltapH/Tat machinery's proofreading mechanism must operate after precursor recognition but before the committed step in transport.

  9. Isolation of a large cholecystokinin precursor from canine brain.

    PubMed Central

    Eysselein, V E; Reeve, J R; Shively, J E; Miller, C; Walsh, J H

    1984-01-01

    Cholecystokinin (CCK)-like immunoreactivity (CCK-LI) in a pool of 12 dog brains was extracted sequentially into boiling water and cold 2% trifluoroacetic acid. Gel filtration on Sephadex G-50 revealed three main molecular forms detected by a carboxyl-terminal antibody; one was eluted in the position of CCK-58 (58 amino acid residues long); a second, in the position of CCK-8; and a third, near the radioactive iodide marker. When the CCK-LI was purified by affinity chromatography using carboxyl-terminal CCK antibody followed by three steps of reversed-phase high-pressure liquid chromatography, three components were isolated and characterized by sequence microanalysis. The smallest component was the pentapeptide common to gastrin and CCK. The second peak was eluted in the same region as synthetic CCK octapeptide, and sequence analysis showed that the chemical structure of this biologically active region of canine CCK is identical to that found in sheep and pig brains. The 22-residue amino-terminal sequence of brain CCK-58 was: Ala-Val-Gln-Lys-Val-Asp-Gly-Glu-Pro-Arg-Ala-His-Leu-Gly -Ala-Leu-leu-Ala-Arg-Tyr-Ile-Gln-, the same as the sequence found for canine intestinal CCK-58 from this pool of dogs. This is the same sequence others have reported for porcine brain CCK-58 lacking nine amino acid residues (CCK-58 desnonapeptide) except that the porcine peptide had a serine in position 9. The canine CCK amino-terminal sequence differed from the sequence Ala-Gln-Lys-Val-Asn-Ser previously reported for intestinal CCK-58 purified from another pool of dog tissue, but the rest of the residues identified were identical in the two peptides. CCK-58 may be a molecular precursor of the smaller forms of CCK in brain as well as in gut. PMID:6093106

  10. Temporal pattern of incorporation of /sup 3/H precursors into pituitary glycoproteins and their subsequent release

    SciTech Connect

    Grotjan, H.E. Jr.

    1982-04-01

    The temporal pattern of incorporation of various /sup 3/H precursors into glycoproteins by rat anterior pituitaries incubated in vitro and the release of /sup 3/H-glycoproteins was examined. (/sup 3/H)Leucine incorporation was linear with respect to time and (/sup 3/H)leucine-containing macromolecules appeared in the media in about 1 hr. The temporal pattern of (/sup 3/H)mannose incorporation and release was similar. (/sup 3/H)Galactose and (/sup 3/H)fucose were incorporated after apparent time of delays of approximately 15 min and soon thereafter (20-25 min) appeared in the medium in /sup 3/H-glycoproteins. Thus, these precursors appear to be added as terminal residues. (/sup 3/H)Glucosamine exhibited a pattern intermediate between (/sup 3/H)leucine and (/sup 3/H)fucose whereas (/sup 3/H)GlcNAc appeared to be incorporated as a terminal residue.

  11. Explorations Precursor Robotic Missions (xPRM)

    NASA Video Gallery

    Jay Jenkins delivers a presentation from the Exploration Precursor Robotic Missions (xPRM) study team on May 25, 2010, at the NASA Exploration Enterprise Workshop held in Galveston, TX. The purpose...

  12. Photoacoustic infrared analysis of nickel catalysts precursors

    NASA Astrophysics Data System (ADS)

    Pasieczna, S.; Ryczkowski, J.

    2006-11-01

    Photoacoustic spectroscopy (FT-IR/PAS) has been used for identification of different forms of nickel precursors formed during CIM (classical impregnation method) and DIM (double impregnation method) process and different pH of the solution containing nickel ions.

  13. Biochemical Removal of HAP Precursors From Coal

    SciTech Connect

    Olson, G.; Tucker, L.; Richards, J.

    1997-07-01

    This project addresses DOE`s interest in advanced concepts for controlling emissions of air toxics from coal-fired utility boilers. We are determining the feasibility of developing a biochemical process for the precombustion removal of substantial percentages of 13 inorganic hazardous air pollutant (HAP) precursors from coal. These HAP precursors are Sb, As, Be, Cd, Cr, Cl, Co, F, Pb, Hg, Mn, Ni, and Se. Although rapid physical coal cleaning is done routinely in preparation plants, biochemical processes for removal of HAP precursors from coal potentially offer advantages of deeper cleaning, more specificity, and less coal loss. Compared to chemical processes for coal cleaning, biochemical processes potentially offer lower costs and milder process conditions. Pyrite oxidizing bacteria, most notably Thiobacillusferrooxidans, are being evaluated in this project for their ability to remove HAP precursors from U.S. coals.

  14. Progress in molecular precursors for electronic materials

    SciTech Connect

    Buhro, W.E.

    1996-09-01

    Molecular-precursor chemistry provides an essential underpinning to all electronic-materials technologies, including photovoltaics and related areas of direct interest to the DOE. Materials synthesis and processing is a rapidly developing field in which advances in molecular precursors are playing a major role. This article surveys selected recent research examples that define the exciting current directions in molecular-precursor science. These directions include growth of increasingly complex structures and stoichiometries, surface-selective growth, kinetic growth of metastable materials, growth of size-controlled quantum dots and quantum-dot arrays, and growth at progressively lower temperatures. Continued progress in molecular-precursor chemistry will afford precise control over the crystal structures, nanostructures, and microstructures of electronic materials.

  15. Hydridosiloxanes as precursors to ceramic products

    DOEpatents

    Blum, Yigal D.; Johnson, Sylvia M.; Gusman, Michael I.

    1997-01-01

    A method is provided for preparing ceramic precursors from hydridosiloxane starting materials and then pyrolyzing these precursors to give rise to silicious ceramic materials. Si--H bonds present in the hydridosiloxane starting materials are catalytically activated, and the activated hydrogen atoms may then be replaced with nonhydrogen substituents. These preceramic materials are pyrolyzed in a selected atmosphere to give the desired ceramic product. Ceramic products which may be prepared by this technique include silica, silicon oxynitride, silicon carbide, metal silicates, and mullite.

  16. Hydridosiloxanes as precursors to ceramic products

    DOEpatents

    Blum, Y.D.; Johnson, S.M.; Gusman, M.I.

    1997-06-03

    A method is provided for preparing ceramic precursors from hydridosiloxane starting materials and then pyrolyzing these precursors to give rise to silicious ceramic materials. Si-H bonds present in the hydridosiloxane starting materials are catalytically activated, and the activated hydrogen atoms may then be replaced with nonhydrogen substituents. These preceramic materials are pyrolyzed in a selected atmosphere to give the desired ceramic product. Ceramic products which may be prepared by this technique include silica, silicon oxynitride, silicon carbide, metal silicates, and mullite.

  17. Biochemical removal of HAP precursors from coal. Technical progress report, January--March 1996

    SciTech Connect

    1996-08-01

    Shake flask bioleaching tests were conducted with Pittsburgh NO. 8 and Indiana No. 5 coal. Bacteria removed pyritic sulfur from both coals at maximum rates of 5 to 9% per day, which was about 20 times the abiotic rate of pyrite oxidation. Concentrations of inorganic hazardous air pollutant (HAP) precursor elements in starting coal, bioleached coal and in leach solutions were measured. Of the 13 HAP precursors, significant amounts of arsenic, cobalt, cadmium, manganese, and nickel were removed from both coals by bacterial activity and also by the acidic leach solutions in control flasks. Little or no mercury, lead, beryllium, chromium, antimony, fluorine or chlorine was removed from the coals. Selenium was bioleached from both coals as determined by analysis of Se in leach solutions. However, analyses of Se in starting coal and in coal residues remains problematic. With very few exceptions, mass balances for the HAP precursors ranged from 80 to 120%. Improved analytical methods were developed for measuring concentrations of Hg, Se, As, and Sb in coal. Shake flask tests with pyrite oxidizing bacteria were conducted on Pittsburgh No. 8 and Indiana No. 5 coal. Concentrations of HAP precursors in the starting coal, leach solutions, and final coal residues were measured. A column leaching-rotating biological contactor (RBC) unit was assembled and a column leach test with Pittsburgh No. 8 coal was begun.

  18. α-Ketoacids as precursors for phenylalanine and tyrosine labelling in cell-based protein overexpression.

    PubMed

    Lichtenecker, Roman J; Weinhäupl, Katharina; Schmid, Walther; Konrat, Robert

    2013-12-01

    (13)C-α-ketoacid metabolic precursors of phenylalanine and tyrosine effectively enter the metabolism of a protein overexpressing E. coli strain to label Phe- and Tyr-residues devoid of any cross-labelling. The methodology gives access to highly selective labelling patterns as valuable tools in protein NMR spectroscopy without the need of (15)N-chiral amino acid synthesis using organic chemistry.

  19. A survey on levels and seasonal changes of assimilable organic carbon (AOC) and its precursors in drinking water.

    PubMed

    Ohkouchi, Yumiko; Ly, Bich Thuy; Ishikawa, Suguru; Aoki, Yusuke; Echigo, Shinya; Itoh, Sadahiko

    2011-10-01

    In Japan, customers' concerns about chlorinous odour in drinking water have been increasing. One promising approach for reducing chlorinous odour is the minimization of residual chlorine in water distribution, which requires stricter control of organics to maintain biological stability in water supply systems. In this investigation, the levels and seasonal changes of assimilable organic carbon (AOC) and its precursors in drinking water were surveyed to accumulate information on organics in terms of biological stability. In tap water samples purified through rapid sand filtration processes, the average AOC concentration was 174 microgC/L in winter and 60 microgC/L in summer. This difference seemed to reflect the seasonal changes of AOC in the natural aquatic environment. On the other hand, very little or no AOC could be removed after use of an ozonation-biological activated carbon (BAC) process. Especially in winter, waterworks should pay attention to BAC operating conditions to improve AOC removal. The storage of BAC effluent with residual chlorine at 0.05-0.15 mgCl2/L increased AOC drastically. This result indicated the possibility that abundant AOC precursors remaining in the finished water could contribute to newly AOC formation during water distribution with minimized residual chlorine. Combined amino acids, which remained at roughly equivalent to AOC in finished water, were identified as major AOC precursors. Prior to minimization of residual chlorine, enhancement of the removal abilities for both AOC and its precursors would be necessary.

  20. The PreA4(695) precursor protein of Alzheimer's disease A4 amyloid is encoded by 16 exons.

    PubMed

    Lemaire, H G; Salbaum, J M; Multhaup, G; Kang, J; Bayney, R M; Unterbeck, A; Beyreuther, K; Müller-Hill, B

    1989-01-25

    Alzheimer's disease (AD) is characterized by the cerebral deposition of fibrillar aggregates of the amyloid A4 protein. Complementary DNA's coding for the precursor of the amyloid A4 protein have been described. In order to identify the structure of the precursor gene relevant clones from several human genomic libraries were isolated. Sequence analysis of the various clones revealed 16 exons to encode the 695 residue precursor protein (PreA4(695] of Alzheimer's disease amyloid A4 protein. The DNA sequence coding for the amyloid A4 protein is interrupted by an intron. This finding supports the idea that amyloid A4 protein arises by incomplete proteolysis of a larger precursor, and not by aberrant splicing.

  1. Improved method for measuring transparent exopolymer particles (TEP) and their precursors in fresh and saline water.

    PubMed

    Villacorte, Loreen O; Ekowati, Yuli; Calix-Ponce, Helga N; Schippers, Jan C; Amy, Gary L; Kennedy, Maria D

    2015-03-01

    Transparent exopolymer particles (TEP) and their precursors produced by phyto-/bacterio-planktons in fresh and marine aquatic environments are increasingly considered as a major contributor to organic/particulate and biological fouling in micro-/ultra-filtration and reverse osmosis membrane (RO) systems. However, currently established methods which are based on Alcian blue (AB) staining and spectrophotometric techniques do not measure TEP-precursors and have the tendency to overestimate concentration in brackish/saline water samples due to interference of salinity on AB staining. Here we propose a new semi-quantitative method which allows measurement of both TEP and their colloidal precursors without the interference of salinity. TEP and their precursors are first retained on 10 kDa membrane, rinsed with ultra-pure water, and re-suspended in ultra-pure water by sonication and stained with AB, followed by exclusion of TEP-AB precipitates by filtration and absorbance measurement of residual AB. The concentration is then determined based on the reduction of AB absorbance due to reaction with acidic polysaccharides, blank correction and calibration with Xanthan gum standard. The extraction procedure allows concentration of TEP and their pre-cursors which makes it possible to analyse samples with a wide range of concentrations (down to <0.1 mg Xeq/L). This was demonstrated through application of the method for monitoring these compounds in algal cultures and a full-scale RO plant. The monitoring also revealed that concentrations of the colloidal precursors were substantially higher than the concentration of TEP themselves. In the RO plant, complete TEP removal was observed over the pre-treatment processes (coagulation-sedimentation-filtration and ultrafiltration) but the TEP precursors were not completely removed, emphasising the importance of measuring this colloidal component to better understand the role of TEP and acidic polysaccharides in RO membrane fouling.

  2. 40 CFR 766.38 - Reporting on precursor chemical substances.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Reporting on precursor chemical... § 766.38 Reporting on precursor chemical substances. (a) Identification of precursor chemical substances. Precursor chemical substances are produced under conditions that will not yield HDDs and HDFs, but...

  3. Sequestration and Transport of Lignin Monomeric Precursors

    SciTech Connect

    Liu, C.J.; Miao, Y.-C.; Zhang, K.-W.

    2011-01-18

    Lignin is the second most abundant terrestrial biopolymer after cellulose. It is essential for the viability of vascular plants. Lignin precursors, the monolignols, are synthesized within the cytosol of the cell. Thereafter, these monomeric precursors are exported into the cell wall, where they are polymerized and integrated into the wall matrix. Accordingly, transport of monolignols across cell membranes is a critical step affecting deposition of lignin in the secondarily thickened cell wall. While the biosynthesis of monolignols is relatively well understood, our knowledge of sequestration and transport of these monomers is sketchy. In this article, we review different hypotheses on monolignol transport and summarize the recent progresses toward the understanding of the molecular mechanisms underlying monolignol sequestration and transport across membranes. Deciphering molecular mechanisms for lignin precursor transport will support a better biotechnological solution to manipulate plant lignification for more efficient agricultural and industrial applications of cell wall biomass.

  4. Nozzle designs with pitch precursor ablatives

    NASA Technical Reports Server (NTRS)

    Blevins, H. R.; Bedard, R. J.

    1976-01-01

    Recent developments in carbon phenolic ablatives for solid rocket motor nozzles have yielded a pitch precursor carbon fiber offering significant raw material availability and cost saving advantages as compared to conventional rayon precursor material. This paper discusses the results of an experimental program conducted to assess the thermal performance and characterize the thermal properties of pitch precursor carbon phenolic ablatives. The end result of this program is the complete thermal characterization of pitch fabric, pitch mat, hybrid pitch/rayon fabric and pitch mat molding compound. With these properties determined an analytic capability now exists for predicting the thermal performance of these materials in rocket nozzle liner applications. Further planned efforts to verify material performance and analytical prediction procedures through actual rocket motor firings are also discussed.

  5. Precursors prior to type IIn supernova explosions are common: Precursor rates, properties, and correlations

    SciTech Connect

    Ofek, Eran O.; Steinbok, Aviram; Arcavi, Iair; Gal-Yam, Avishay; Tal, David; Ben-Ami, Sagi; Yaron, Ofer; Sullivan, Mark; Shaviv, Nir J.; Kulkarni, Shrinivas R.; Nugent, Peter E.; Kasliwal, Mansi M.; Cenko, S. Bradley; Silverman, Jeffrey M.

    2014-07-10

    There is a growing number of Type IIn supernovae (SNe) which present an outburst prior to their presumably final explosion. These precursors may affect the SN display, and are likely related to poorly charted phenomena in the final stages of stellar evolution. By coadding Palomar Transient Factory (PTF) images taken prior to the explosion, here we present a search for precursors in a sample of 16 Type IIn SNe. We find five SNe IIn that likely have at least one possible precursor event (PTF 10bjb, SN 2010mc, PTF 10weh, SN 2011ht, and PTF 12cxj), three of which are reported here for the first time. For each SN we calculate the control time. We find that precursor events among SNe IIn are common: at the one-sided 99% confidence level, >50% of SNe IIn have at least one pre-explosion outburst that is brighter than 3 × 10{sup 7} L{sub ☉} taking place up to 1/3 yr prior to the SN explosion. The average rate of such precursor events during the year prior to the SN explosion is likely ≳ 1 yr{sup –1}, and fainter precursors are possibly even more common. Ignoring the two weakest precursors in our sample, the precursors rate we find is still on the order of one per year. We also find possible correlations between the integrated luminosity of the precursor and the SN total radiated energy, peak luminosity, and rise time. These correlations are expected if the precursors are mass-ejection events, and the early-time light curve of these SNe is powered by interaction of the SN shock and ejecta with optically thick circumstellar material.

  6. Residue chemistry guidelines.

    PubMed

    Olinger, C L; Schmitt, R D; Zager, E

    1993-01-01

    Residue chemistry guidelines are designed to determine what the potential residues in food are and how much may be present as a result of pesticide application, so that a tolerance level may be established. Some requirements are established to assist in the enforcement of tolerances by the USDA, FDA, and the states. I realize I have given you a quick overview of the residue chemistry requirements. There are many documents which are available if you should require more information, such as the Subdivision O Residue Chemistry Guidelines, Standard Evaluation Procedures (which are used by reviewers when evaluating the studies), the Data Reporting Guidelines (which provide guidance on preparing final reports), and the Technical Guidance from Phase III of Reregistration. We have also released various papers on studies when additional guidance is required. Most of these documents are available from NTIS. I hope you will consider this information when auditing residue chemistry studies. As I see the efforts that you, the QA professionals, have made to educate yourselves on residue chemistry studies through programs such as this meeting, I have a little more confidence in answering the question "Do you trust them?" with a "Yes." Thank you.

  7. Polymeric precursors for fibers and matrices

    NASA Technical Reports Server (NTRS)

    Hurwitz, Frances I.

    1992-01-01

    Candidate polymeric precursors for ceramic fiber and matrix processing are discussed, with a view to the advantages and disadvantages of this approach relative to existing alternatives. The properties of ceramic products thus derived are noted to strongly depend on the molecular weight and structure of the starting polymer; in particular, the ceramic's composition and morphology are dependent on the character and extent of crosslinking, as well as on the path of pyrolysis. While large and complex structural ceramic components may ultimately be obtainable by these means, the polymer-precursor method is still in its developmental infancy.

  8. High-Solids Polyimide Precursor Solutions

    NASA Technical Reports Server (NTRS)

    Chuang, Chun-Hua (Inventor)

    2004-01-01

    The invention is a highly concentrated stable solution of polymide precursors (monometers) having a solids content ranging from about 80 to 98 percent by weight in lower aliphatic alcohols i.e. methyl and/or ethylalcohol. the concentrated polyimide precursos solution comparisons effective amounts of at least one aromatic diamine, at least one aromatic dianhydride, and a monofunctional endcap including monoamines, monoanhydrides and lower alkyl esters of said monoanhydrides. These concentrated polyimide precursor solutions are particularly useful for the preparation of fibrous prepregs and composites for use in structural materials for military and civil applications.

  9. Import of rat ornithine transcarbamylase precursor into mitochondria: two-step processing of the leader peptide

    PubMed Central

    1987-01-01

    The mitochondrial matrix enzyme ornithine transcarbamylase (OTC) is synthesized on cytoplasmic polyribosomes as a precursor (pOTC) with an NH2-terminal extension of 32 amino acids. We report here that rat pOTC synthesized in vitro is internalized and cleaved by isolated rat liver mitochondria in two, temporally separate steps. In the first step, which is dependent upon an intact mitochondrial membrane potential, pOTC is translocated into mitochondria and cleaved by a matrix protease to a product designated iOTC, intermediate in size between pOTC and mature OTC. This product is in a trypsin-protected mitochondrial location. The same intermediate-sized OTC is produced in vivo in frog oocytes injected with in vitro-synthesized pOTC. The proteolytic processing of pOTC to iOTC involves the removal of 24 amino acids from the NH2 terminus of the precursor and utilizes a cleavage site two residues away from a critical arginine residue at position 23. In a second cleavage step, also catalyzed by a matrix protease, iOTC is converted to mature OTC by removal of the remaining eight residues of leader sequence. To define the critical regions in the OTC leader peptide required for these events, we have synthesized OTC precursors with alterations in the leader. Substitution of either an acidic (aspartate) or a "helix-breaking" (glycine) amino acid residue for arginine 23 of the leader inhibits formation of both iOTC and OTC, without affecting translocation. These mutant precursors are cleaved at an otherwise cryptic cleavage site between residues 16 and 17 of the leader. Interestingly, this cleavage occurs at a site two residues away from an arginine at position 15. The data indicate that conversion of pOTC to mature OTC proceeds via the formation of a third discrete species: an intermediate-sized OTC. The data suggest further that, in the rat pOTC leader, the essential elements required for translocation differ from those necessary for correct cleavage to either iOTC or mature

  10. Atomic layer deposition and chemical vapor deposition precursor selection method application to strontium and barium precursors.

    PubMed

    Holme, Timothy P; Prinz, Fritz B

    2007-08-23

    A new selection method for atomic layer deposition (ALD) or chemical vapor deposition (CVD) precursors is proposed and tested. Density functional theory was used to simulate Sr and Ba precursors, and several precursors were selected and used to grow films via ALD as test cases for the precursor selection method. The precursors studied were M(x)2 (M = Sr, Ba; x = tetramethylheptanedionate (tmhd), acetylacetonate (acac), hexafluoroacetylacetonate (hfac), cyclopentadienyl (H(5)C(5)), pentamethylcyclopentadienyl (Me(5)C(5)), n-propyltetramethylcyclopentadienyl (PrMe(4)C(5)), tris(isopropylcyclopentadienyl) (Pr(3)(i)H(2)C(5)), tris(isopropylcyclopentadienyl)(THF) (Pr(3)(i)H(2)C(5))(OC(4)H(8)), tris(isopropylcyclopentadienyl)(THF)2 (Pr(3)(i)H(2)C(5))(OC(4)H(8))2, tris(tert-butylcyclopentadienyl) (Bu(3)(t)H(2)C(5)), tris(tert-butylcyclopentadienyl)(THF) (Bu(3)(t)H(2)C(5))(OC(4)H(8)), heptafluoro-2,2-dimethyl-3,5-octanedionate (fod)). The energy required to break bonds between the metal atom and the ligands was calculated to find which precursors react most readily. In the case of tmhd and Cp precursors, the energy required to break bonds in the precursor ligand was studied to evaluate the most likely mechanism of carbon incorporation into the film. Trends for Ba and Sr followed each other closely, reflecting the similar chemistry among alkaline earth metals. The diketonate precursors have stronger bonds to the metals than the Cp precursors, but weaker bonds within the ligand, explaining the carbon contamination found in experimentally grown films. Atomic layer deposition of SrO was tested with Sr(tmhd)2 and Sr(PrMe(4)Cp)2 and oxygen, ozone, and water as oxygen sources. No deposition was measured with tmhd precursors, and SrO films were deposited with PrMe(4)Cp with a source temperature of 200 degrees C and at substrate temperatures between 250 and 350 degrees C with growth rates increasing for oxygen sources in this order: O2 < H2O < O2 + H2O. The experimental results

  11. Cloning and sequence analysis of an Ophiophagus hannah cDNA encoding a precursor of two natriuretic peptide domains.

    PubMed

    Lei, Weiwei; Zhang, Yong; Yu, Guoyu; Jiang, Ping; He, Yingying; Lee, Wenhui; Zhang, Yun

    2011-04-01

    The king cobra (Ophiophagus hannah) is the largest venomous snake. Despite the components are mainly neurotoxins, the venom contains several proteins affecting blood system. Natriuretic peptide (NP), one of the important components of snake venoms, could cause local vasodilatation and a promoted capillary permeability facilitating a rapid diffusion of other toxins into the prey tissues. Due to the low abundance, it is hard to purify the snake venom NPs. The cDNA cloning of the NPs become a useful approach. In this study, a 957 bp natriuretic peptide-encoding cDNA clone was isolated from an O. hannah venom gland cDNA library. The open-reading frame of the cDNA encodes a 210-amino acid residues precursor protein named Oh-NP. Oh-NP has a typical signal peptide sequence of 26 amino acid residues. Surprisingly, Oh-NP has two typical NP domains which consist of the typical sequence of 17-residue loop of CFGXXDRIGC, so it is an unusual NP precursor. These two NP domains share high amino acid sequence identity. In addition, there are two homologous peptides of unknown function within the Oh-NP precursor. To our knowledge, Oh-NP is the first protein precursor containing two NP domains. It might belong to another subclass of snake venom NPs. PMID:21334357

  12. Cloning and sequence analysis of an Ophiophagus hannah cDNA encoding a precursor of two natriuretic peptide domains.

    PubMed

    Lei, Weiwei; Zhang, Yong; Yu, Guoyu; Jiang, Ping; He, Yingying; Lee, Wenhui; Zhang, Yun

    2011-04-01

    The king cobra (Ophiophagus hannah) is the largest venomous snake. Despite the components are mainly neurotoxins, the venom contains several proteins affecting blood system. Natriuretic peptide (NP), one of the important components of snake venoms, could cause local vasodilatation and a promoted capillary permeability facilitating a rapid diffusion of other toxins into the prey tissues. Due to the low abundance, it is hard to purify the snake venom NPs. The cDNA cloning of the NPs become a useful approach. In this study, a 957 bp natriuretic peptide-encoding cDNA clone was isolated from an O. hannah venom gland cDNA library. The open-reading frame of the cDNA encodes a 210-amino acid residues precursor protein named Oh-NP. Oh-NP has a typical signal peptide sequence of 26 amino acid residues. Surprisingly, Oh-NP has two typical NP domains which consist of the typical sequence of 17-residue loop of CFGXXDRIGC, so it is an unusual NP precursor. These two NP domains share high amino acid sequence identity. In addition, there are two homologous peptides of unknown function within the Oh-NP precursor. To our knowledge, Oh-NP is the first protein precursor containing two NP domains. It might belong to another subclass of snake venom NPs.

  13. Basics for Testing Large Earthquake Precursors

    NASA Astrophysics Data System (ADS)

    Romashkova, L. L.; Kossobokov, V. G.; Peresan, A.

    2008-12-01

    Earthquakes, the large or significant ones in particular, are extreme events that, by definition, are the rare ones. Testing candidates to large earthquake precursors implies investigation a small sample of case- histories with the support of specific and sensitive statistical methods and data of different quality, collected in various conditions. Regretfully, in many seismological studies the methods of mathematical statistics are used outside their applicability: earthquakes are evidently not independent events and have heterogeneous, perhaps fractal distribution in space and time. Moreover, the naïve or, conversely, delicately-designed models are considered as a full replacement of seismic phenomena. Although there are many claims of earthquake precursors, most of them should remain in the list of precursor candidates, which have never been tested in any rigorous way, and, in fact, are anecdotal cases of coincidental occurrence. To establish a precursory link between sequences of events of the same or different phenomena, it is necessary to accumulate enough statistics in a rigorous forecast/prediction test, which results, i.e. success-to-failure scores and space-time volume of alarms, must appeal for rejecting hypotheses of random coincidental appearance. We reiterate suggesting to use so-called "Seismic Roulette" null-hypothesis as the most adequate random alternative accounting for the empirical spatial distribution of earthquakes in question and illustrate a few outcomes of Testing Large Earthquake Precursors.

  14. Superconductor precursor mixtures made by precipitation method

    DOEpatents

    Bunker, Bruce C.; Lamppa, Diana L.; Voigt, James A.

    1989-01-01

    Method and apparatus for preparing highly pure homogeneous precursor powder mixtures for metal oxide superconductive ceramics. The mixes are prepared by instantaneous precipitation from stoichiometric solutions of metal salts such as nitrates at controlled pH's within the 9 to 12 range, by addition of solutions of non-complexing pyrolyzable cations, such as alkyammonium and carbonate ions.

  15. Detection of Chemical Precursors of Explosives

    NASA Technical Reports Server (NTRS)

    Li, Jing

    2012-01-01

    Certain selected chemicals associated with terrorist activities are too unstable to be prepared in final form. These chemicals are often prepared as precursor components, to be combined at a time immediately preceding the detonation. One example is a liquid explosive, which usually requires an oxidizer, an energy source, and a chemical or physical mechanism to combine the other components. Detection of the oxidizer (e.g. H2O2) or the energy source (e.g., nitromethane) is often possible, but must be performed in a short time interval (e.g., 5 15 seconds) and in an environment with a very small concentration (e.g.,1 100 ppm), because the target chemical(s) is carried in a sealed container. These needs are met by this invention, which provides a system and associated method for detecting one or more chemical precursors (components) of a multi-component explosive compound. Different carbon nanotubes (CNTs) are loaded (by doping, impregnation, coating, or other functionalization process) for detecting of different chemical substances that are the chemical precursors, respectively, if these precursors are present in a gas to which the CNTs are exposed. After exposure to the gas, a measured electrical parameter (e.g. voltage or current that correlate to impedance, conductivity, capacitance, inductance, etc.) changes with time and concentration in a predictable manner if a selected chemical precursor is present, and will approach an asymptotic value promptly after exposure to the precursor. The measured voltage or current are compared with one or more sequences of their reference values for one or more known target precursor molecules, and a most probable concentration value is estimated for each one, two, or more target molecules. An error value is computed, based on differences of voltage or current for the measured and reference values, using the most probable concentration values. Where the error value is less than a threshold, the system concludes that the target

  16. In silico identification of novel hevein-like peptide precursors.

    PubMed

    Porto, William F; Souza, Valéria A; Nolasco, Diego O; Franco, Octávio L

    2012-11-01

    Lectins are proteins with ability to bind reversibly and non-enzymatically to a specific carbohydrate. They are involved in numerous biological processes and show enormous biotechnological potential. Among plant lectins, the hevein domain is extremely common, being observed in several kinds of lectins. Moreover, this domain is also observed in an important class of antimicrobial peptides named hevein-like peptides. Due to higher cysteine residues conservation, hevein-like peptides could be mined among the sequence databases. By using the pattern CX(4,5)CC[GS]X(2)GXCGX[GST]X(2,3)[FWY]C[GS]X[AGS] novel hevein-like peptide precursors were found from three different plants: Oryza sativa, Vitis vinifera and Selaginella moellendorffii. In addition, an hevein-like peptide precursor from the phytopathogenic fungus Phaeosphaeria nodorum was also identified. The molecular models indicate that they have the same scaffold as others, composed of an antiparallel β-sheet and short helices. Nonetheless, the fungal hevein-like peptide probably has a different disulfide bond pattern. Despite this difference, the complexes between peptide and N,N,N-triacetylglucosamine are stable, according to molecular dynamics simulations. This is the first report of an hevein-like peptide from an organism outside the plant kingdom. The exact role of an hevein-like peptide in the fungal biology must be clarified, while in plants they are clearly involved in plant defense. In summary, data here reported clear shows that an in silico strategy could lead to the identification of novel hevein-like peptides that could be used as biotechnological tools in the fields of health and agribusiness.

  17. Improved (and Singular) Disinfectant Protocol for Indirectly Assessing Organic Precursor Concentrations of Trihalomethanes and Dihaloacetonitriles.

    PubMed

    Do, Thien D; Chimka, Justin R; Fairey, Julian L

    2015-08-18

    Measurements of disinfection byproduct (DBP) organic precursor concentrations (OPCs) are crucial to assess and improve DBP control processes. Typically, formation potential tests - specified in Standard Methods (SM) 5710-B/D - are used to measure OPCs. Here, we highlight several limitations of this protocol for dihaloacetonitriles and trihalomethanes and validate a novel Alternative Method (AM). The effects of pH, disinfectant type (free chlorine and monochloramine), and chlor(am)ine residual (CR) were examined on DBP formation in a suite of waters. Using the SM, DHAN decreased 43-47% as the CR increased from 3 to 5 mg L(-1) as Cl2, compromising OPC assessments. In contrast, a high monochloramine dose (250 mg L(-1) as Cl2) at pH 7.0 (the AM) accurately reflected OPCs. The two methods were compared for assessing DBP precursor removal through three granular activated carbon (GAC) columns in series. Breakthrough profiles assessed using the AM only showed DBP precursor sorption occurred in each column that decreased over time (p = 0.0001). Similarly, the AM facilitated ranking of three types of GAC compared in parallel columns, whereas the SM produced ambiguous results. Fluorescence intensity of a humic-like fluorophore (i.e., I345/425) correlated strongly to precursor removal in the GAC columns. The practical implications of the results are discussed.

  18. Improved (and Singular) Disinfectant Protocol for Indirectly Assessing Organic Precursor Concentrations of Trihalomethanes and Dihaloacetonitriles.

    PubMed

    Do, Thien D; Chimka, Justin R; Fairey, Julian L

    2015-08-18

    Measurements of disinfection byproduct (DBP) organic precursor concentrations (OPCs) are crucial to assess and improve DBP control processes. Typically, formation potential tests - specified in Standard Methods (SM) 5710-B/D - are used to measure OPCs. Here, we highlight several limitations of this protocol for dihaloacetonitriles and trihalomethanes and validate a novel Alternative Method (AM). The effects of pH, disinfectant type (free chlorine and monochloramine), and chlor(am)ine residual (CR) were examined on DBP formation in a suite of waters. Using the SM, DHAN decreased 43-47% as the CR increased from 3 to 5 mg L(-1) as Cl2, compromising OPC assessments. In contrast, a high monochloramine dose (250 mg L(-1) as Cl2) at pH 7.0 (the AM) accurately reflected OPCs. The two methods were compared for assessing DBP precursor removal through three granular activated carbon (GAC) columns in series. Breakthrough profiles assessed using the AM only showed DBP precursor sorption occurred in each column that decreased over time (p = 0.0001). Similarly, the AM facilitated ranking of three types of GAC compared in parallel columns, whereas the SM produced ambiguous results. Fluorescence intensity of a humic-like fluorophore (i.e., I345/425) correlated strongly to precursor removal in the GAC columns. The practical implications of the results are discussed. PMID:26167626

  19. Precursors and pathogenesis of ovarian carcinoma.

    PubMed

    Lim, D; Oliva, E

    2013-04-01

    The ultimate goal of defining cancer specific precursors is to facilitate early detection and intervention before the development of invasive malignancy. Unlike other malignancies involving the female genital tract such as cervical or endometrial carcinomas, precursor lesions of ovarian carcinomas have not been well characterised, resulting in a failure to develop effective screening programs. Recent clinicopathological and molecular studies have provided new insight into the origin and pathogenesis of ovarian carcinomas. It has been shown that ovarian cancer is comprised of different tumour types differing not only in morphology, but also in pathogenesis, molecular alterations and clinical progression. A dualistic model of ovarian carcinogenesis has been proposed. Type I tumours which include low grade serous, low grade endometrioid, clear cell, mucinous carcinomas and Brenner tumours, are generally indolent and tend to be genetically stable, although clear cell carcinoma would probably belong to an intermediate category. They demonstrate a step-wise progression from a benign precursor such as a benign to borderline tumour or endometriosis and are characterised by genetic aberrations targeting specific cell signalling pathways. Type II tumours comprise high grade serous, high grade endometrioid, and undifferentiated carcinomas as well as malignant mixed mesodermal tumours. They are clinically aggressive and exhibit high genetic instability with frequent p53 mutations. Mounting evidence suggests that many high grade serous carcinomas originate from the epithelium of the distal fallopian tube, and that serous tubal intraepithelial carcinoma (STIC) represents the putative precursor of these neoplasms. Low grade serous carcinomas arise via transformation of benign and borderline serous tumours, thought to be derived from inclusion cysts originating from the ovarian surface or tubal epithelium. Recently it has been suggested that papillary tubal hyperplasia may be a

  20. Amyloid precursor protein modulates β-catenin degradation

    PubMed Central

    Chen, Yuzhi; Bodles, Angela M

    2007-01-01

    Background The amyloid precursor protein (APP) is genetically associated with Alzheimer's disease (AD). Elucidating the function of APP should help understand AD pathogenesis and provide insights into therapeutic designs against this devastating neurodegenerative disease. Results We demonstrate that APP expression in primary neurons induces β-catenin phosphorylation at Ser33, Ser37, and Thr41 (S33/37/T41) residues, which is a prerequisite for β-catenin ubiquitinylation and proteasomal degradation. APP-induced phosphorylation of β-catenin resulted in the reduction of total β-catenin levels, suggesting that APP expression promotes β-catenin degradation. In contrast, treatment of neurons with APP siRNAs increased total β-catenin levels and decreased β-catenin phosphorylation at residues S33/37/T41. Further, β-catenin was dramatically increased in hippocampal CA1 pyramidal cells from APP knockout animals. Acute expression of wild type APP or of familial AD APP mutants in primary neurons downregulated β-catenin in membrane and cytosolic fractions, and did not appear to affect nuclear β-catenin or β-catenin-dependent transcription. Conversely, in APP knockout CA1 pyramidal cells, accumulation of β-catenin was associated with the upregulation of cyclin D1, a downstream target of β-catenin signaling. Together, these data establish that APP downregulates β-catenin and suggest a role for APP in sustaining neuronal function by preventing cell cycle reactivation and maintaining synaptic integrity. Conclusion We have provided strong evidence that APP modulates β-catenin degradation in vitro and in vivo. Future studies may investigate whether APP processing is necessary for β-catenin downregulation, and determine if excessive APP expression contributes to AD pathogenesis through abnormal β-catenin downregulation. PMID:18070361

  1. Electromagnetic Whistler Precursors at Supercritical Interplanetary Shocks

    NASA Technical Reports Server (NTRS)

    Wilson, L. B., III

    2012-01-01

    We present observations of electromagnetic precursor waves, identified as whistler mode waves, at supercritical interplanetary shocks using the Wind search coil magnetometer. The precursors propagate obliquely with respect to the local magnetic field, shock normal vector, solar wind velocity, and they are not phase standing structures. All are right-hand polarized with respect to the magnetic field (spacecraft frame), and all but one are right-hand polarized with respect to the shock normal vector in the normal incidence frame. Particle distributions show signatures of specularly reflected gyrating ions, which may be a source of free energy for the observed modes. In one event, we simultaneously observe perpendicular ion heating and parallel electron acceleration, consistent with wave heating/acceleration due to these waves.

  2. [Presentation of the Lunar Precursor Robotics Program

    NASA Technical Reports Server (NTRS)

    Lavoie, Anthony R.

    2008-01-01

    The Lunar Precursor Robotics Program (LPRP) is the host program for the Exploration Systems Mission Directorate's (ESMD) lunar robotic precursor missions to the Moon. The program includes two missions, the Lunar Reconnaissance Orbiter (LRO), and the Lunar CRater Observation and Sensing Satellite (LCROSS). Both missions will provide the required lunar information to support development and operations of those systems required for Human lunar return. LPRP is developing a lunar mapping plan, Called the Lunar Mapping and Modeling Project, to create the capability to archive and present all data from LRO, LCROSS, historical lunar missions, and international lunar missions for future mission planning and operations. LPRP is also developing its educational and public outreach activities for the Vision for Space Exploration's first missions. LPRP is working closely with the Science Mission Directorate as their lunar activities come into focus.

  3. Nonlinear magnetohydrodynamics of edge localized mode precursors

    SciTech Connect

    Guo, Z. B.; Wang, Lu; Wang, X. G.

    2015-02-15

    A possible origin of edge-localized-mode (ELM) precursors based on nonlinear ideal peeling-ballooning mode is reported. Via nonlinear variational principle, a nonlinear evolution equation of the radial displacement is derived and solved, analytically. Besides an explosive growth in the initial nonlinear phase, it is found that the local displacement evolves into an oscillating state in the developed nonlinear phase. The nonlinear frequency of the ELM precursors scales as ω{sub pre}∼x{sup 1/3}ξ{sup ^}{sub ψ,in}{sup 2/3}n, with x position in radial direction, ξ{sup ^}{sub ψ,in} strength of initial perturbation, and n toroidal mode number.

  4. Becoming an adolescent father: precursors and parenting.

    PubMed

    Fagot, B I; Pears, K C; Capaldi, D M; Crosby, L; Leve, C S

    1998-11-01

    Precursors and outcomes of adolescent pregnancy receive considerable research attention; however, most studies deal with adolescent mothers. This study examined whether risk factors that are precursors to adolescent fatherhood would be consistent with the family coercion model (G. R. Patterson, 1976) of the development of antisocial behavior in childhood. Hypotheses were tested in the Oregon Youth Study (OYS) sample of 206 at-risk boys who were first seen at 9 or 10 years of age. At 18-20 years of age, the profiles for the 35 adolescent fathers included more arrests and substance use than the other OYS participants. At around 2 years of age, 40% of the children had no contact with their fathers. The children, compared with a normative control sample, had somewhat greater health risks. The at-risk parents, compared with a control sample, were observed to show higher levels of negative reactions when their children were working on a puzzle task. PMID:9823506

  5. Enhancement of the aspartame precursor synthetic activity of an organic solvent-stable protease.

    PubMed

    Ogino, Hiroyasu; Tsuchiyama, Shotaro; Yasuda, Masahiro; Doukyu, Noriyuki

    2010-03-01

    The PST-01 protease is highly stable and catalyzes the synthesis of the aspartame precursor with high reaction yields in the presence of organic solvents. However, the synthesis rate using the PST-01 protease was slower than that observed when thermolysin was used. Structural comparison of both enzymes showed particular amino acid differences near the active center. These few residue differences in the PST-01 protease were mutated to match those amino acid types found in thermolysin. The mutated PST-01 proteases at the 114th residue from tyrosine to phenylalanine showed enhancement of synthetic activity. This activity was found to be similar to thermolysin. In addition, mutating the residue in the PST-01 protease with arginine and serine showed more improvement of the activity. The mutant PST-01 protease should be more useful than thermolysin for the synthesis of the aspartame precursor, because this enzyme has higher stability and activity in the presence of organic solvents. The results show the potential of organic solvent-stable enzymes as industrial catalysts.

  6. Human blood-group MN and precursor specificities: structural and biological aspects.

    PubMed

    Springer, G F; Desai, P R

    1975-03-01

    The human blood-group MM and NN antigens carry 2 to 4 immunodominant groupings per repeating subunit and differ only by one sialic acid residue per immunodominant group. This residue covers in the MM antigen the beta-D-galactopyranosyl group that is terminal in the N immunodominant structure and that, together with a terminal alpha-linked N-acetylneuraminic acid residue, is responsible for N specificity. M specificity was readily converted into N specificity by mild acid treatment. N structure is the immediate biochemical precursor of M structure, and M and N antigenic specificities are not determined by two allelic genes as believed hitherto. The NN antigen was inactivated by beta-D-galactosidase as well as by removal of N-acetylneuraminic acid. Some of the reactivities of the NN antigen, lost upon beta-D-galactosidase treatment, reappeared on subsequent partial N-acetylneuraminic acid removal. The structure uncovered by complete sialic acid depletion of MN antigens is the Thomsen-Friedenreich T antigen, the specificity of which is determined by beta-D-galactopyranosyl groups. Beta-D-Galactosidase treatment transformed the T antigen into one possessing Tnactivity. The significance of blood-group MN active substances extends to human breast cancer, where MN antigens were found in benign and malignant glands, but some of their precursors in cancerous tissue only.

  7. Calculations of precursor propagation in dispersive dielectrics.

    SciTech Connect

    Bacon, Larry Donald

    2003-08-01

    The present study is a numerical investigation of the propagation of electromagnetic transients in dispersive media. It considers propagation in water using Debye and composite Rocard-Powles-Lorentz models for the complex permittivity. The study addresses this question: For practical transmitted spectra, does precursor propagation provide any features that can be used to advantage over conventional signal propagation in models of dispersive media of interest? A companion experimental study is currently in progress that will attempt to measure the effects studied here.

  8. Precursors to radiopharmaceutical agents for tissue imaging

    DOEpatents

    Srivastava, Prem C.; Knapp, Jr., Furn F.

    1988-01-01

    A class of radiolabeled compounds to be used in tissue imaging that exhibits rapid brain uptake, good brain:blood radioactivity ratios, and long retention times. The imaging agents are more specifically radioiodinated aromatic amines attached to dihydropyridine carriers, that exhibit heart as well as brain specificity. In addition to the radiolabeled compounds, classes of compounds are also described that are used as precursors and intermediates in the preparation of the imaging agents.

  9. Efficient photovoltaic conversion of graphene-carbon nanotube hybrid films grown from solid precursors

    NASA Astrophysics Data System (ADS)

    Gan, Xin; Lv, Ruitao; Bai, Junfei; Zhang, Zexia; Wei, Jinquan; Huang, Zheng-Hong; Zhu, Hongwei; Kang, Feiyu; Terrones, Mauricio

    2015-09-01

    Large-area (e.g. centimeter size) graphene sheets are usually synthesized via pyrolysis of gaseous carbon precursors (e.g. methane) on metal substrates like Cu using chemical vapor deposition (CVD), but the presence of grain boundaries and the residual polymers during transfer deteriorates significantly the properties of the CVD graphene. If carbon nanotubes (CNTs) can be covalently bonded to graphene, the hybrid system could possess excellent electrical conductivity, transparency and mechanical strength. In this work, conducting and transparent CNT-graphene hybrid films were synthesized by a facile solid precursor pyrolysis method. Furthermore, the synthesized CNT-graphene hybrid films display enhanced photovoltaic conversion efficiency when compared to devices based on CNT membranes or graphene sheets. Upon chemical doping, the graphene-CNT/Si solar cells reveal power conversion efficiencies up to 8.50%.

  10. Characterization of GaSb thin films from tailor-made single-source precursors

    NASA Astrophysics Data System (ADS)

    Seemayer, Andreas; Hommes, Alexander; Hümann, Sascha; Schulz, Stephan; Wandelt, Klaus

    2008-11-01

    We investigated the growth and surface properties of GaSb thin films on a Si(0 0 1) substrate prepared using a tailor-made fully alkyl-substituted heterocyclic single-source precursor. The precursor properties were monitored during the evaporation process by residual gas analysis (RGA). The initial film growth was monitored by Auger electron spectroscopy (AES). Using a high-vacuum cold wall reactor, dense GaSb films could be produced and were characterized by AES, AFM and synchrotron X-ray photoelectron spectroscopy (S-XPS). The results are discussed in terms of a correlation of the electronic and geometrical properties with the composition and structure of the films.

  11. Ionospheric precursors for crustal earthquakes in Italy

    NASA Astrophysics Data System (ADS)

    Perrone, L.; Korsunova, L. P.; Mikhailov, A. V.

    2010-04-01

    Crustal earthquakes with magnitude 6.0>M≥5.5 observed in Italy for the period 1979-2009 including the last one at L'Aquila on 6 April 2009 were considered to check if the earlier obtained relationships for ionospheric precursors for strong Japanese earthquakes are valid for the Italian moderate earthquakes. The ionospheric precursors are based on the observed variations of the sporadic E-layer parameters (h'Es, fbEs) and foF2 at the ionospheric station Rome. Empirical dependencies for the seismo-ionospheric disturbances relating the earthquake magnitude and the epicenter distance are obtained and they have been shown to be similar to those obtained earlier for Japanese earthquakes. The dependences indicate the process of spreading the disturbance from the epicenter towards periphery during the earthquake preparation process. Large lead times for the precursor occurrence (up to 34 days for M=5.8-5.9) tells about a prolong preparation period. A possibility of using the obtained relationships for the earthquakes prediction is discussed.

  12. Scalar model for frictional precursors dynamics

    PubMed Central

    Taloni, Alessandro; Benassi, Andrea; Sandfeld, Stefan; Zapperi, Stefano

    2015-01-01

    Recent experiments indicate that frictional sliding occurs by nucleation of detachment fronts at the contact interface that may appear well before the onset of global sliding. This intriguing precursory activity is not accounted for by traditional friction theories but is extremely important for friction dominated geophysical phenomena as earthquakes, landslides or avalanches. Here we simulate the onset of slip of a three dimensional elastic body resting on a surface and show that experimentally observed frictional precursors depend in a complex non-universal way on the sample geometry and loading conditions. Our model satisfies Archard's law and Amontons' first and second laws, reproducing with remarkable precision the real contact area dynamics, the precursors' envelope dynamics prior to sliding, and the normal and shear internal stress distributions close to the interfacial surface. Moreover, it allows to assess which features can be attributed to the elastic equilibrium, and which are attributed to the out-of-equilibrium dynamics, suggesting that precursory activity is an intrinsically quasi-static physical process. A direct calculation of the evolution of the Coulomb stress before and during precursors nucleation shows large variations across the sample, explaining why earthquake forecasting methods based only on accumulated slip and Coulomb stress monitoring are often ineffective. PMID:25640079

  13. Scalar model for frictional precursors dynamics.

    PubMed

    Taloni, Alessandro; Benassi, Andrea; Sandfeld, Stefan; Zapperi, Stefano

    2015-01-01

    Recent experiments indicate that frictional sliding occurs by nucleation of detachment fronts at the contact interface that may appear well before the onset of global sliding. This intriguing precursory activity is not accounted for by traditional friction theories but is extremely important for friction dominated geophysical phenomena as earthquakes, landslides or avalanches. Here we simulate the onset of slip of a three dimensional elastic body resting on a surface and show that experimentally observed frictional precursors depend in a complex non-universal way on the sample geometry and loading conditions. Our model satisfies Archard's law and Amontons' first and second laws, reproducing with remarkable precision the real contact area dynamics, the precursors' envelope dynamics prior to sliding, and the normal and shear internal stress distributions close to the interfacial surface. Moreover, it allows to assess which features can be attributed to the elastic equilibrium, and which are attributed to the out-of-equilibrium dynamics, suggesting that precursory activity is an intrinsically quasi-static physical process. A direct calculation of the evolution of the Coulomb stress before and during precursors nucleation shows large variations across the sample, explaining why earthquake forecasting methods based only on accumulated slip and Coulomb stress monitoring are often ineffective. PMID:25640079

  14. Synthesis of nanoporous nickel thin films from various precursors

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Balk, T. John

    2014-09-01

    Multiple approaches to fabricate nanoporous nickel (np-Ni) thin films from NiCu, NiAl, NiFe and NiMg precursors are presented. Deposition of precursor films, dealloying and characterization of the nanoporous films by electron microscopy are discussed. All precursor alloys can yield np-Ni. However, dealloying of NiMg precursor films yields the most consistent, open-porosity structure with a ligament size of 7 nm, comparable to that of Raney nickel.

  15. Residual stresses in material processing

    SciTech Connect

    Kozaczek, K.J.; Watkins, T.R.; Hubbard, C.R.; Wang, Xun-Li; Spooner, S.

    1994-09-01

    Material manufacturing processes often introduce residual stresses into the product. The residual stresses affect the properties of the material and often are detrimental. Therefore, the distribution and magnitude of residual stresses in the final product are usually an important factor in manufacturing process optimization or component life prediction. The present paper briefly discusses the causes of residual stresses. It then adresses the direct, nondestructive methods of residual stress measurement by X-ray and neutron diffraction. Examples are presented to demonstrate the importance of residual stress measurement in machining and joining operations.

  16. 21 CFR 1308.47 - Control of immediate precursors.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Control of immediate precursors. 1308.47 Section... SUBSTANCES Hearings § 1308.47 Control of immediate precursors. Pursuant to section 201(e) of the Act (21 U.S... Federal Register an order controlling an immediate precursor. The order shall designate the schedule...

  17. 40 CFR 766.38 - Reporting on precursor chemical substances.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Reporting on precursor chemical... SUBSTANCES CONTROL ACT DIBENZO-PARA-DIOXINS/DIBENZOFURANS Specific Chemical Testing/Reporting Requirements § 766.38 Reporting on precursor chemical substances. (a) Identification of precursor chemical...

  18. 40 CFR 766.38 - Reporting on precursor chemical substances.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Reporting on precursor chemical... SUBSTANCES CONTROL ACT DIBENZO-PARA-DIOXINS/DIBENZOFURANS Specific Chemical Testing/Reporting Requirements § 766.38 Reporting on precursor chemical substances. (a) Identification of precursor chemical...

  19. 40 CFR 766.38 - Reporting on precursor chemical substances.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Reporting on precursor chemical... SUBSTANCES CONTROL ACT DIBENZO-PARA-DIOXINS/DIBENZOFURANS Specific Chemical Testing/Reporting Requirements § 766.38 Reporting on precursor chemical substances. (a) Identification of precursor chemical...

  20. 40 CFR 1065.705 - Residual and intermediate residual fuel.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... specifications for fuels meeting the definition of residual fuel in 40 CFR 80.2, including fuels marketed as... for Residual Fuel Characteristic Unit Category ISO-F- RMA 30 RMB 30 RMD 80 RME 180 RMF 180 RMG 380...

  1. 40 CFR 1065.705 - Residual and intermediate residual fuel.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... specifications for fuels meeting the definition of residual fuel in 40 CFR 80.2, including fuels marketed as... for Residual Fuel Characteristic Unit Category ISO-F- RMA 30 RMB 30 RMD 80 RME 180 RMF 180 RMG 380...

  2. SRC Residual fuel oils

    DOEpatents

    Tewari, Krishna C.; Foster, Edward P.

    1985-01-01

    Coal solids (SRC) and distillate oils are combined to afford single-phase blends of residual oils which have utility as fuel oils substitutes. The components are combined on the basis of their respective polarities, that is, on the basis of their heteroatom content, to assure complete solubilization of SRC. The resulting composition is a fuel oil blend which retains its stability and homogeneity over the long term.

  3. Water treatment residuals

    SciTech Connect

    Billings, C.H.

    1994-01-01

    Solutions to an environmental problem often create other environmental problems. That surely is the case in the water supply field. By providing new or expanded water treatment systems to comply with the maximum contaminant levels and treatment mandates of the Safe Drinking Water Act, water purveyors are generating large volumes of residuals that must be managed, ultimately disposed of, or recycled. Numerous federal, state, and local laws govern the management, transport, disposal, and recycling of wastes produced by water treatment systems. Because these laws can result in exorbitant waste disposal costs, restricting some projects entirely, water suppliers need to consider residual disposal early in the siting, selection, and design of treatment projects. To inform water suppliers about residual laws, AWWA commissioned a study published as a Water Industry Technical Action Fund report. In addition to identifying and describing applicable laws at the federal level and in six of the states, the study revealed a series of findings as to the consequences of those laws to water suppliers. This article is a brief overview of the findings of the report.

  4. Molecular composition and mobility of torbanite precursors: Implications for the structure of coal

    USGS Publications Warehouse

    Wilson, M.A.; Batts, B.D.; Hatcher, P.G.

    1988-01-01

    Coorongite, a torbanite precursor found in South Australia, and algal residues derived from Botryococcus braunii and other algae have been examined by solid-state 13C NMR techniques. The majority of carbon in these materials is present as (CH2)n. However, variable-temperature studies show that a considerable proportion of the alkyl chains have unusual dipolar-dephasing behavior and are more mobile than in rigid solids. It is suggested that these mobile structures contribute to the so-called "guest phases" in coal. The data are also consistent with a vascular and algal model of coal. ?? 1988 American Chemical Society.

  5. Meat flavor precursors and factors influencing flavor precursors--A systematic review.

    PubMed

    Khan, Muhammad Issa; Jo, Cheorun; Tariq, Muhammad Rizwan

    2015-12-01

    Flavor is the sensory impression sensed by taste and smell buds and is a leading factor determining the meat quality and purchasing decision of the consumer. Meat flavor is characteristic of volatiles produced as a result of reactions of non-volatile components that are induced thermally. The water soluble compounds having low molecular weight and meat lipids are important precursors of cooked meat flavor. The Maillard reaction, lipid oxidation, and vitamin degradation are leading reactions during cooking which develop meat flavor from uncooked meat with little aroma and bloody taste. The pre-slaughter and postmortem factors like animal breed, sex, age, feed, aging and cooking conditions contribute to flavor development of cooked meat. The objective of this review is to highlight the flavor chemistry, meat flavor precursors and factors affecting meat flavor precursors.

  6. Efficient amidation of C-peptide deleted NPY precursors by non-endocrine cells is affected by the presence of Lys-Arg at the C-terminus.

    PubMed

    Wulff, B S; Catipovic, B; Okamoto, H; Gether, U; Schwartz, T W; Johansen, T E

    1993-02-01

    Post-translational processing of peptide precursors producing amidated, biologically active peptides generally occurs in specially differentiated endocrine or neural cells. However, we have previously shown that a C-peptide-deleted precursor of neuropeptide Y (NPY1-39) in which the precursor terminates in the sequence Gly-Lys-Arg was partially amidated by the non-endocrine cell line, CHO. In the present study we show that two other non-endocrine cell lines, NIH 3T3 and BHK, also possess amidating activities and that the NPY1-39 precursor was completely converted to NPY1-36 amide by the NIH 3T3 cell line. The role of the two basic residues (Lys-Arg) in the C-terminus was studied by transfection of a construct encoding a NPY precursor terminating with glycine alone. Both the CHO and NIH 3T3 cell lines, transfected with this construct, secreted a significantly smaller fraction of NPY reactive material as amidated NPY compared to the fraction of amidated NPY secreted by the cells transfected with the NPY1-39 precursor. It is concluded that the capacity to perform C-terminal amidation appears to be a universal feature of eukaryotic cells and that the carboxypeptidase E-like enzyme influences the amidation process, beyond its known ability to remove the C-terminal basic residues.

  7. Systems and methods for detection of blowout precursors in combustors

    DOEpatents

    Lieuwen, Tim C.; Nair, Suraj

    2006-08-15

    The present invention comprises systems and methods for detecting flame blowout precursors in combustors. The blowout precursor detection system comprises a combustor, a pressure measuring device, and blowout precursor detection unit. A combustion controller may also be used to control combustor parameters. The methods of the present invention comprise receiving pressure data measured by an acoustic pressure measuring device, performing one or a combination of spectral analysis, statistical analysis, and wavelet analysis on received pressure data, and determining the existence of a blowout precursor based on such analyses. The spectral analysis, statistical analysis, and wavelet analysis further comprise their respective sub-methods to determine the existence of blowout precursors.

  8. On Verification of Earthquake Precursors (Invited)

    NASA Astrophysics Data System (ADS)

    Kossobokov, V. G.

    2009-12-01

    Although there are many claims of earthquake precursors, most of them should remain in the list of precursor candidates, which have never been tested in any rigorous way, and, in fact, are anecdotal cases of coincidental occurrence. To establish a precursory link between sequences of events of the same or different phenomena, it is necessary to accumulate enough statistics in a rigorous forecast/prediction test, which results, i.e. success-to-failure scores and space-time volume of alarms, must appeal for rejecting hypotheses of random coincidental appearance. We reiterate suggesting so-called “Seismic Roulette” null-hypothesis as the most adequate random alternative accounting for the empirical spatial distribution of earthquakes in question: (i) Consider a roulette wheel with as many sectors as the number of earthquake locations from a sample catalog, a sector per each location and (ii) make your bet according to prediction (i.e., determine, which locations are inside area of alarm, and put one chip in each of the corresponding sectors); (iii) Nature turns the wheel; (iv) accumulate statistics of wins and losses along with the number of chips spent. If a precursor in charge of prediction exposes an imperfection of Seismic Roulette then, having in mind optional “antipodal strategy”, one can make the predictions efficient, so that the wins will systematically outscore the losses. Sounds easy, we know! Seismology is juvenile and its appropriate statistical tools to-date may have a "medieval flavor" for those who hurry up to apply a fuzzy language of a highly developed probability theory and consider delicately-designed models as a full replacement of seismic phenomena. To become "quantitatively probabilistic" earthquake forecasts/predictions must be defined with a scientific accuracy. Following the most popular objectivists' viewpoint on probability, we cannot claim "probabilities" adequate without a long series of "yes/no" forecast/prediction outcomes

  9. The Mars 2001 Athena Precursor Experiment (APEX)

    NASA Technical Reports Server (NTRS)

    Squyres, S. W.; Arvidson, R.; Bell, J. F., III; Carr, M.; Christensen, P.; DesMarais, D.; dUston, C.; Economou, T.; Gorevan, S.; Klingelhoefer, G.

    1999-01-01

    The Athena Precursor Experiment (APEX) is a suite of scientific instruments for the Mars Surveyor Program 2001 (MSP'01) lander. The major elements of the APEX pay load are: (1) Pancam/Mini-TES, a combined stereo color imager and mid-infrared point spectrometer. (2) An Alpha-Proton-X-Ray Spectrometer (APXS) for in-situ elemental analysis. (3) A Mossbauer Spectrometer for in-situ determination of the mineralogy of Fe-bearing rocks and soils. (4) A Magnet Array that can separate magnetic soil particles from non-magnetic ones.

  10. Effects of Detergents on Ribosomal Precursor Subunits of Bacillus megaterium

    PubMed Central

    Body, Barbara A.; Brownstein, Bernard H.

    1978-01-01

    Cell extracts prepared by osmotic lysis of protoplasts were analyzed by sucrose gradient sedimentation. In the absence of detergents, ribosomal precursor particles were found in a gradient fraction which sedimented faster than mature 50S subunits and in two other fractions coincident with mature 50S and 30S ribosomal subunits. Phospholipid, an indicator of membrane, was shown to be associated with only the fastest-sedimenting ribosomal precursor particle fraction. After the extracts were treated with detergents, all phospholipid was found at the top of the gradients. Brij 58, Triton X-100, and Nonidet P-40 did not cause a change in the sedimentation values of precursors; however, the detergents deoxycholate or LOC (Amway Corp.) disrupted the fastest-sedimenting precursor and converted the ribosomal precursor subunits which sedimented at the 50S and 30S positions to five different classes of more slowly sedimenting particles. Earlier reports on the in vivo assembly of ribosomal subunits have shown that several stages of ribosomal precursor subunits exist, and, in the presence of the detergents deoxycholate and LOC, which had been used to prepare cell extracts, the precursors sedimented more slowly. Our data are consistent with the hypothesis that those detergents selectively modify the structure of ribosomal precursors and lend further support to the hypothesis that the in vivo ribosomal precursor subunits have 50S and 30S sedimentation values. In addition, these data support the idea that the ribosomal precursor particles found in the fast-sedimenting fraction may constitute a unique precursor fraction. PMID:412833

  11. Effects of detergents on ribosomal precursor subunits of Bacillus megaterium.

    PubMed

    Body, A; Brownstein, B H

    1978-01-01

    Cell extracts prepared by osmotic lysis of protoplasts were analyzed by sucrose gradient sedimentation. In the absence of detergents, ribosomal precursor particles were found in a gradient fraction which sedimented faster than mature 50S subunits and in two other fractions coincident with mature 50S and 30S ribosomal subunits. Phospholipid, an indicator of membrane, was shown to be associated with only the fastest-sedimenting ribosomal precursor particle fraction. After the extracts were treated with detergents, all phospholipid was found at the top of the gradients. Brij 58, Triton X-100, and Nonidet P-40 did not cause a change in the sedimentation values of precursors; however, the detergents deoxycholate or LOC (Amway Corp.) disrupted the fastest-sedimenting precursor and converted the ribosomal precursor subunits which sedimented at the 50S and 30S positions to five different classes of more slowly sedimenting particles. Earlier reports on the in vivo assembly of ribosomal subunits have shown that several stages of ribosomal precursor subunits exist, and, in the presence of the detergents deoxycholate and LOC, which had been used to prepare cell extracts, the precursors sedimented more slowly. Our data are consistent with the hypothesis that those detergents selectively modify the structure of ribosomal precursors and lend further support to the hypothesis that the in vivo ribosomal precursor subunits have 50S and 30S sedimentation values. In addition, these data support the idea that the ribosomal precursor particles found in the fast-sedimenting fraction may constitute a unique precursor fraction.

  12. Solid state polymerization and crystallography of polyimide precursors. Ph.D. Thesis - Va. Univ.

    NASA Technical Reports Server (NTRS)

    Wakelyn, N. T.

    1974-01-01

    Although the production of crystallinity in a polymeric system has historically led to commerically useful properties, the polyimides, prized for their high temperature characteristics, as customarily synthesized by melt or solution casting, are amorphous. It is shown that polymide containing residual crystallinity can be synthesized by isothermal annealing of crystals of the salt of the diisopropyl ester of pyromellitic acid and phenylene diamine. The reaction is topochemical in that the geometry of the polymer product is dependent upon that of the crystalline precursor. Infrared spectroscopy reveals the presence of imide absorption in the polymer, while powder diffractometry suggests residual crystallinity. Single crystal X-ray analysis of the monomer yields a structure of chains of alternating acid and base suggesting that the monomer is amenable to polymerization with a minimum of geometrical disruption.

  13. Characterisation of mRNAs encoding the precursor for human apolipoprotein CI.

    PubMed Central

    Knott, T J; Robertson, M E; Priestley, L M; Urdea, M; Wallis, S; Scott, J

    1984-01-01

    cDNA clones encoding human apolipoprotein CI have been isolated from an adult liver cDNA library. Apo CI mRNA was shown to have two species of approximately 580 and 560 bases by RNA blot hybridisation. The intracellular precursor of apo CI was inferred from the cDNA sequence to be an 83 amino acid polypeptide consisting of the 57 residue mature protein and an additional 26 residue amino terminal signal peptide. The 5' untranslated regions of the messages are 63 and 40 bases as determined by primer extension and the 3' untranslated region 111 bases. A polyadenylation signal is situated 10 bases 3' of the poly(A) tall. The mRNA level of apo CI in human liver was significantly greater than that of apo All and apo E. Images PMID:6328444

  14. Significant residual fluorinated alcohols present in various fluorinated materials.

    PubMed

    Dinglasan-Panlilio, Mary Joyce A; Mabury, Scott A

    2006-03-01

    Polyfluorinated telomer alcohols and sulfonamides are classes of compounds recently identified as precursor molecules to the perfluorinated acids detected in the environment. Despite the detection and quantification of these volatile compounds in the atmosphere, their sources remain unknown. Both classes of compounds are used in the synthesis of various fluorosurfactants and incorporated in polymeric materials used extensively in the carpet, textile, and paper industries. This study has identified the presence of residual unbound fluoro telomer alcohols (FTOHs) in varying chain lengths (C6-C14) in several commercially available and industrially applied polymeric and surfactant materials. NMeFOSE, a perfluoroalkyl sulfonamido alcohol, was also detected in a commercially available carpet protector product. A method was developed to remove these residual compounds from polymeric and surfactant materials by dispersion in water and stripping of the volatiles using a constant flow of air and trapping on XAD resin. Using gas chromatography mass spectrometry analysis, it was determined that the fluorinated materials examined consist of 0.04-3.8% residual alcohols on a fluoro alcohol to dry mass basis. These values indicate that residual alcohols, left unreacted and unbound from the manufacturing process of fluorinated polymers and surfactants, could be a significant source of the polyfluorinated telomer alcohols and sulfonamides released into the environment. This study suggests that elimination or reduction of these residual alcohols from all marketed fluorinated polymers and fluorosurfactants is key in reducing the prevalence of perfluorinated acids formed in the environment.

  15. Chemical cleavage of the overexpressed mitochondrial F1beta precursor with CNBr: a new strategy to construct an import-competent preprotein.

    PubMed

    Pavlov, P F; Moberg, P; Zhang, X P; Glaser, E

    1999-07-01

    We have isolated a soluble import-competent 15 kDa N-terminal fragment of the overexpressed Nicotiana plumbaginifolia F1beta precursor of the ATP synthase (N15pF1beta). The isolation was achieved after chemical cleavage, with CNBr, of the insoluble precursor collected in inclusion bodies, followed by purification of the fragment using ion-exchange chromatography. The purity of the final product was estimated to be more than 99%. N15pF1beta contained a presequence of 54 amino acid residues (except for the N-terminal methionine residue) and 82 N-terminal residues of the mature protein. N15pF1beta was shown to be imported into isolated potato tuber mitochondria and to be processed by the isolated mitochondrial processing peptidase (MPP) integrated into the cytochrome bc1 complex of the respiratory chain. Addition of N15pF1beta at micromolar concentrations resulted in the inhibition of import of F1beta precursor and alternative oxidase precursor, synthesized in vitro, into isolated mitochondria as well as the processing of these precursors catalysed by the isolated MPP-bc1 complex. N15pF1beta conjugated via a biotin link to avidin blocked import sites even after the reisolation of mitochondria and inhibited the import of the mitochondrial precursors, indicating that it can be used as a substrate for the generation of a stable translocation intermediate. Our results present a novel procedure for the production of an N-terminal fragment of the F1beta precursor that contains all information necessary for mitochondrial targeting and processing and that can be used for structural and functional studies of the mitochondrial protein import system. This procedure has a general value because it can be used for the production of chemical quantities of any mitochondrial import substrate and presequence peptide. PMID:10377249

  16. Cellular Precursors of the Coronary Arteries

    PubMed Central

    Muñoz-Chápuli, Ramón; González-Iriarte, Mauricio; Carmona, Rita; Atencia, Gerardo; Macías, David; Pérez-Pomares, José María

    2002-01-01

    Coronary vessels develop from a primary vascular network that differentiates in the subepicardium through a process of vasculogenesis, that is, self-assembly of mesenchymal vascular progenitors. Further growth of the subepicardial vascular plexus through a complex process of angiogenesis, vascular remodeling, and arterialization of specific branches gives rise to the definitive coronary system. This report is intended to summarize current knowledge on the origin of the coronary vascular progenitors and to provide new insights suggested by recent findings. It has been established that the mesenchymal precursors of the vascular smooth muscle cells and the adventitial fibroblasts originate from an epithelial-mesenchymal transformation of the epicardial mesothelium. We report herein experimental evidence that the precursors of the coronary endothelium are also epicardium-derived cells (EPDCs). The evidence shown includes co-localization of mesothelial and endothelial molecular markers as well as cell lineage studies performed through direct labeling of the epicardial cells. If this proposal is confirmed, the early EPDCs might be found to have a competence similar to that shown by the recently discovered bipotential vascular progenitor cells, which are able to differentiate into endothelium or smooth muscle depending on their exposure to VEGF or PDGF-BB. It is conceivable that the earliest EPDCs differentiate into endothelial cells in response to myocardially secreted VEGF, while subsequent EPDCs, recruited by the nascent capillaries via PDGFRβ signaling, differentiate into pericytes and smooth muscle cells. (Tex Heart Inst J 2002;29:243–9) PMID:12484607

  17. Diagenesis and catagenesis of marine kerogen precursors

    SciTech Connect

    Rafalska-Bloch, J.

    1987-01-01

    The approaches used were (1) investigations of marine kerogen precursors in a natural environment, e.g., in reefal carbonate sediments (in Puerto Rico and Belize) and (2) laboratory modeling of the condensation of marine kerogen precursors, i.e., amino acids and sugars and subsequent formation and reactions of melanoidin polymers. The organic facies model of a reef environment was developed from the analysis of (1) total organic carbon, (2) visual protokerogen types, (3) Rock-Eval indices and (4) sedimentological considerations. Rates of melanoidin formation, incorporation of amino acid and glucose into the melanoidin polymers and their attendant decrease in the melanoidin solutions were evaluated. The observed pattern was that of initially rapid loss of biomonomers from the melanoidin solutions and concomitant formation of melanoidin polymers. The rate of incorporation of amino acids into the polymers is related partly to glucose concentration and partly to the type of amino acid. The racemization rates of amino acids were also investigated. During the course of melanoidin formation the original amino acid abundances and stereochemistry are redistributed during simulated diagenesis. This may have implications for natural environments where diagenesis may obscure the original depositional signal and complicate geochronological studies. Catagenetic evolution of both synthetic geopolymer (lysine, histidine, arginine, glucose - melanoidin) and natural geopolymers (Belizian organic matter) was simulated using hydrous pyrolysis.

  18. The residual caries dilemma.

    PubMed

    Weerheijm, K L; Groen, H J

    1999-12-01

    Restorative dentistry is based on the assumption that bacterial infection of demineralized dentine should prompt operative intervention. One of the concepts of practical dentistry is to create a favourable environment for caries arrest with minimal operative intervention. The progress of remaining primary caries is key to any discussion of this concept. This discussion is important for the atraumatic restorative treatment (ART) approach, since the removal of all carious dentine is sometimes difficult using hand instruments only. In this paper the results of possible measures to guard against the effects of residual carious and its consequences are reviewed, in order to obtain an impression of the justification for (in)complete excavation of occlusal dentinal caries. Three types of measure are considered: isolating the caries process from the oral environment, excavating the carious dentine, and using a cariostatic filling material. Each of these measures contributes to the arrest of the caries process. However, none of these measures can arrest this process by itself. A combination of all three seems necessary. It is concluded that although residual caries does not seem to be the criterion for rerestoration, one has to strive for as complete caries removal as possible. If this cannot be fulfilled the sealing capacities of the filling material seem to be more important than its cariostatic properties. PMID:10600078

  19. Effects of particles on stability of flow-induced precursors.

    PubMed

    Zhu, Peng-Wei; Phillips, Andrew W; Edward, Graham

    2012-02-01

    The effect of two colorant particles with different surface geometries on the stability of shear-induced precursors in isotactic polypropylene was studied after the cessation of shear flow at 140 °C. In the absence of particles, the shear-induced precursors survived for at least 100 s after the shear flow ended. The presence of particles was found to stabilize lower molecular weight chains assisting in the formation of additional shear-induced precursors. The precursors thus formed in the samples containing particles contained two oriented clusters with different molecular weights. Incorporation of lower molecular weight chains in the precursors led to increased dissolution rates of the shear-induced precursors. Particle surface geometry was found to influence precursor dissolution, with planar particles stabilizing the shear-induced precursors to a much greater extent than curved particles. The particles investigated thus act like structural probes to follow quantitatively the dissolution process of precursors after shear and importantly to infer the formation of precursors during shear.

  20. Fluorescent Tagged Heparan Sulfate Precursor Oligosaccharides to Probe the Enzymatic Action of Heparitinase I

    PubMed Central

    Babu, Ponnusamy; Kuberan, Balagurunathan

    2009-01-01

    Heparitinase I, a key lyase enzyme essential for structural analysis of heparan sulfate (HS), degrades HS domains which are undersulfated at glucuronyl residues through an elimination mechanism. Earlier studies employed viscosimetric measurements and electrophoresis to deduce the mechanism of action of heparitinase I and two other related lyases, heparitinase II and heparitinase III. However, these findings lack molecular evidence for the intermediates formed and could not distinguish whether the cleavage occurred from the reducing end or non-reducing end. In this report, 2-aminoacridone (2-AMAC) labeled HS precursor oligosaccharides of various sizes were prepared to investigate the mechanism of heparitinase I mediated depolymerization using sensitive and quantitative methodologies. Furthermore, fluorescence (2-AMAC) tagging of heparan sulfate precursor oligosaccharides allowed us to distinguish fragments that result from cleavage of the substrates at various time intervals and sites further away from the reducing and non-reducing ends of oligosaccharide substrates. This study provides first direct molecular evidence for a predominantly random endolytic mechanism of elimination of HS precursor oligosaccharides by heparitinase I. This robust strategy can be adapted to deduce the mechanism of action of other heparitinases and also to deduce structural information of complex heparan sulfate oligosaccharides of biological importance. PMID:19732739

  1. Chondrule synthesis using fine-grained precursors

    NASA Astrophysics Data System (ADS)

    Fox, George Ernest

    2002-11-01

    High temperature petrologic experiments have been used in order to reproduce the textures of chondrules, which are rounded to irregularly shaped ferromagnesion silicate objects. Such experiments shed light on the conditions that existed and mechanisms that operated in the early solar nebula, as natural chondrules are believed to have formed there due to some type of heating event. The exact nature of this heating event and the conditions that existed at the time of the formation of the solar nebula are not completely understood. Chondrules, which are believed to be composed of some of the oldest remnants of the solar system, nebular condensates, are the basic components of chondrites. Chondrites comprise ˜82% of all meteorites. Despite years of petrographic examination and experimental petrology, the thermal history of chondrules still remains uncertain. Natural chondrules exhibit a variety of different textures ranging from glassy, barred, porphyritic, microporphyritc to protoporphyritc. Petrologic experiments in a muffle tube furnace under controlled fugacity conditions using type IAB bulk composition analogs have been successful in reproducing each of these textures in the laboratory. Charges are prepared, heated, water quenched, mounted, polished and photographed using back-scattered electron imagery. Subsequent analysis provides numerical data, which can then be used to calculate the nominal grain size of the olivine crystals in each charge. Porphyritic chondrules are the most abundant in nature by far and any model for chondrule formation must be capable of producing porphyritic textures. To reproduce this texture in the laboratory, however, seems to require a very narrow range of maximum temperature and soak time parameters even when using a variety of different types of fine-grained and agglomerated olivine precursor material. Experiments undertaken in this study bring into question some of the basic assumptions of various classical models of chondrule

  2. Cloning and characterization of a cDNA sequence encoding the precursor of a chlorotoxin-like peptide from the Chinese scorpion Buthus martensii Karsch.

    PubMed

    Zeng, X C; Li, W X; Zhu, S Y; Peng, F; Zhu, Z H; Wu, K L; Yiang, F H

    2000-08-01

    A full-length cDNA sequence encoding the precursor of a venom peptide with homology to chlorotoxin (named BmKCT) was isolated from a cDNA library made from the venom glands of the Chinese Scorpion Buthus martensii Karsch. The encoded precursor of BmKCT was 59 amino acid residues long including a signal peptide of 24 residues and a mature toxin of 35 residues with four disulfide bridges. The sequence of BmKCT is similar (68% identities) to that of chlorotoxin isolated from Leiurus quinguestriatus quinquestriatus. BmKCT is the first report of the cDNA sequences encoding four-disulfide-bridged short-chain toxins from Buthus martensuii Karsch so far.

  3. Bunyamwera orthobunyavirus glycoprotein precursor is processed by cellular signal peptidase and signal peptide peptidase

    PubMed Central

    Shi, Xiaohong; Botting, Catherine H.; Li, Ping; Niglas, Mark; Brennan, Benjamin; Shirran, Sally L.; Szemiel, Agnieszka M.; Elliott, Richard M.

    2016-01-01

    The M genome segment of Bunyamwera virus (BUNV)—the prototype of both the Bunyaviridae family and the Orthobunyavirus genus—encodes the glycoprotein precursor (GPC) that is proteolytically cleaved to yield two viral structural glycoproteins, Gn and Gc, and a nonstructural protein, NSm. The cleavage mechanism of orthobunyavirus GPCs and the host proteases involved have not been clarified. In this study, we investigated the processing of BUNV GPC and found that both NSm and Gc proteins were cleaved at their own internal signal peptides (SPs), in which NSm domain I functions as SPNSm and NSm domain V as SPGc. Moreover, the domain I was further processed by a host intramembrane-cleaving protease, signal peptide peptidase, and is required for cell fusion activities. Meanwhile, the NSm domain V (SPGc) remains integral to NSm, rendering the NSm topology as a two-membrane-spanning integral membrane protein. We defined the cleavage sites and boundaries between the processed proteins as follows: Gn, from residue 17–312 or nearby residues; NSm, 332–477; and Gc, 478–1433. Our data clarified the mechanism of the precursor cleavage process, which is important for our understanding of viral glycoprotein biogenesis in the genus Orthobunyavirus and thus presents a useful target for intervention strategies. PMID:27439867

  4. Strain Observation Affected by Groundwater-Level Change in Seismic Precursor Monitoring

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Cao, Daiyong; Zhang, Jingfa

    2016-09-01

    Groundwater extraction is one of the most typical disturbance factors for strain observation in seismic precursor monitoring. The statistic regression method is used to study based on the relation between the variation of strain and the groundwater level. The least square regression linear model is built between the annual variation of Sangzi groundwater level and the Xiaoxinzhuang strain data. Such model meets t test with significance level α = 0. 0 5 , which confirms that groundwater-level change in each year affects strain measurement significantly and strain's trend variation is related to groundwater-level change. Consequently, a new correction method about strain data is put forward based on the groundwater-level annual variation to eliminate the trend change. Results indicate that the accumulated residual deformation causes the horizontal displacement and strain change, which is on account of that the amount of groundwater recharge is less than that of extraction around Xiaoxinzhuang cave, the phreatic surface continues to descend, and residual deformation accumulates and leads to local subsidence area. Therefore, the decline trend change of strain is related to groundwater-level change and is not seismic precursor.

  5. Design of Aerosol Coating Reactors: Precursor Injection

    PubMed Central

    Buesser, Beat; Pratsinis, Sotiris E.

    2013-01-01

    Particles are coated with thin shells to facilitate their processing and incorporation into liquid or solid matrixes without altering core particle properties (coloristic, magnetic, etc.). Here, computational fluid and particle dynamics are combined to investigate the geometry of an aerosol reactor for continuous coating of freshly-made titanium dioxide core nanoparticles with nanothin silica shells by injection of hexamethyldisiloxane (HMDSO) vapor downstream of TiO2 particle formation. The focus is on the influence of HMDSO vapor jet number and direction in terms of azimuth and inclination jet angles on process temperature and coated particle characteristics (shell thickness and fraction of uncoated particles). Rapid and homogeneous mixing of core particle aerosol and coating precursor vapor facilitates synthesis of core-shell nanoparticles with uniform shell thickness and high coating efficiency (minimal uncoated core and free coating particles). PMID:23658471

  6. The amyloid precursor protein: beyond amyloid

    PubMed Central

    Zheng, Hui; Koo, Edward H

    2006-01-01

    The amyloid precursor protein (APP) takes a central position in Alzheimer's disease (AD) pathogenesis: APP processing generates the β-amyloid (Aβ) peptides, which are deposited as the amyloid plaques in brains of AD individuals; Point mutations and duplications of APP are causal for a subset of early onset of familial Alzheimer's disease (FAD). Not surprisingly, the production and pathogenic effect of Aβ has been the central focus in AD field. Nevertheless, the biological properties of APP have also been the subject of intense investigation since its identification nearly 20 years ago as it demonstrates a number of interesting putative physiological roles. Several attractive models of APP function have been put forward recently based on in vitro biochemical studies. Genetic analyses of gain- and loss-of-function mutants in Drosophila and mouse have also revealed important insights into its biological activities in vivo. This article will review the current understanding of APP physiological functions. PMID:16930452

  7. Silsesquioxanes as precursors to ceramic composites

    NASA Technical Reports Server (NTRS)

    Hurwitz, Frances I.; Hyatt, Lizbeth H.; Gorecki, Joy; Damore, Lisa

    1987-01-01

    Silsesquioxanes having the general structure RSiO sub 1.5, where R = methyl, propyl, or phenyl, melt flow at 70 to 100 C. Above 100 C, free -OH groups condense. At 225 C further crosslinking occurs, and the materials form thermosets. Pyrolysis, with accompanying loss of volatiles, takes place at nominally 525 C. At higher temperatures, the R group serves as an internal carbon soruce for carbo-thermal reduction to SiC accompanied by the evolution of CO. By blending silsesquioxanes with varying R groups, both the melt rheology and composition of the fired ceramic can be controlled. Fibers can be spun from the melt which are stable in argon in 1400 C. The silsesquioxanes also were used as matrix precursors for Nicalon and alpha-SiC platelet reinforced composites.

  8. Filler/ Polycarbosilane Systems as CMC Matrix Precursors

    NASA Technical Reports Server (NTRS)

    Hurwitz, Frances I.

    1998-01-01

    Pyrolytic conversion of polymeric precursors to ceramics is accompanied by loss of volatiles and large volume changes. Infiltration of a low viscosity polymer into a fiber preform will fill small spaces within fiber tows by capillary forces, but create large matrix cracks within large, intertow areas. One approach to minimizing shrinkage and reducing the number of required infiltration cycles is to use particulate fillers. In this study, Starfire allylhydridopolycarbosilane (AHPCS) was blended with a silicon carbide powder, with and without dispersant, using shear mixing. The polymer and polymer/particle interactions were characterized using nuclear magnetic resonance, differential scanning calorimetry, thermogravimetric analysis and rheometry. Polymer/particulate slurries and suspensions were used to infiltrate a figidized preform of an eight ply five harness satin CG Nicalon fiber having a dual layer BN/SiC interface coating, and the resulting composites characterized by optical and scanning electron microscopy.

  9. Nanostructured carbonaceous materials from molecular precursors.

    PubMed

    Hoheisel, Tobias N; Schrettl, Stephen; Szilluweit, Ruth; Frauenrath, Holger

    2010-09-01

    Nanostructured carbonaceous materials, that is, carbon materials with a feature size on the nanometer scale and, in some cases, functionalized surfaces, already play an important role in a wide range of emerging fields, such as the search for novel energy sources, efficient energy storage, sustainable chemical technology, as well as organic electronic materials. Furthermore, such materials might offer solutions to the challenges associated with the on-going depletion of nonrenewable energy resources or climate change, and they may promote further breakthroughs in the field of microelectronics. However, novel methods for their preparation will be required that afford functional carbon materials with controlled surface chemistry, mesoscopic morphology, and microstructure. A highly promising approach for the synthesis of such materials is based on the use of well-defined molecular precursors. PMID:20661971

  10. Residual gas analyzer calibration

    NASA Technical Reports Server (NTRS)

    Lilienkamp, R. H.

    1972-01-01

    A technique which employs known gas mixtures to calibrate the residual gas analyzer (RGA) is described. The mass spectra from the RGA are recorded for each gas mixture. This mass spectra data and the mixture composition data each form a matrix. From the two matrices the calibration matrix may be computed. The matrix mathematics requires the number of calibration gas mixtures be equal to or greater than the number of gases included in the calibration. This technique was evaluated using a mathematical model of an RGA to generate the mass spectra. This model included shot noise errors in the mass spectra. Errors in the gas concentrations were also included in the valuation. The effects of these errors was studied by varying their magnitudes and comparing the resulting calibrations. Several methods of evaluating an actual calibration are presented. The effects of the number of gases in then, the composition of the calibration mixture, and the number of mixtures used are discussed.

  11. Effects of peer mediation on preschoolers' compliance and compliance precursors.

    PubMed

    Beaulieu, Lauren; Hanley, Gregory P; Roberson, Aleasha A

    2013-01-01

    We used a multiple baseline design across participants to evaluate the effects of teaching 4 typically developing preschoolers to attend to their names and to a group call (referred to as precursors) on their compliance with typical classroom instructions. We then measured the extent to which the effects on both precursors and compliance were maintained when the teaching procedures were removed. Levels of compliance eventually decreased for all children. A multiple baseline design across participants was then used to evaluate the effects of peer mediation on the maintenance of precursors and compliance. Peer mediation involved teaching the children to either remind one another to engage in a precursor or praise one another for engaging in a precursor. Compliance improved with all children as a function of teaching precursors, and these changes were maintained through the use of peer mediation.

  12. The precursors of the xylene ring in riboflavine

    PubMed Central

    Ali, S. N.; Al-Khalidi, U. A. S.

    1966-01-01

    1. The nature of the precursors of the xylene ring in riboflavine was reinvestigated with growing as well as resting cells of Eremothecium ashbyii. 2. The incorporation of acetoin into riboflavine was very low; further, [2-14C]pyruvate and [1-14C]acetate were equally effective as precursors of lumichrome, and pyruvate was much more active as a precursor of acetoin. These results exclude acetoin as a direct precursor of riboflavine. 3. Addition of unlabelled glucose decreased the incorporation of [14C]acetate into riboflavine more than it decreased the conversion of acetate into carbon dioxide, indicating that acetate is not a direct riboflavine precursor. 4. The incorporation of various sugars and dilution experiments suggest that a derivative of the intermediates of the pentose phosphate cycle is the precursor of the xylene ring in riboflavine. PMID:5938640

  13. Precursors to glycogen in ovine fetuses

    SciTech Connect

    Levitsky, L.L.; Paton, J.B.; Fisher, D.E. )

    1988-11-01

    Postprandial hepatic glycogenesis in the adult animal is now felt to proceed largely through gluconeogenic pathways rather than directly from glucose. The ovine fetus, like the mature sheep, lacks specific hepatic glucokinase. Therefore, the authors examined the role of lactate as a fetal glycogenic precursor in seven chronically catheterized 125-day sheep fetuses. Fetuses were infused with L-(U-{sup 14}C)lactate and D-(3-{sup 3}H)glucose, while maternal glucose was maintained at 50 mg/dl. Mean fetal hepatic glycogen specific activity ({mu}Ci/mg {times} 10{sup 3}) was 0.82 {plus minus} 0.08 for {sup 14}C and 2.6 {plus minus} 0.4 for {sup 3}H, whereas fetal renal glycogen specific activity was 0.46 {plus minus} 0.22 for {sup 14}C and 0.78 {plus minus} 0.16 for {sup 3}H. In contrast, ({sup 14}C)glucose specific activity was undetectable in blood and mean ({sup 3}H)glucose specific activity was 8.9 {plus minus} 1.3 {mu}Ci/mg {times} 10{sup 3}. The least detectable specific activity of ({sup 14}C)glucose did not differ significantly from the ({sup 14}C)glycogen enrichment in liver, whereas ({sup 3}H)glucose specific activity was significantly greater than ({sup 3}H)glycogen enrichment. The authors conclude that glycogenesis from glucose is partly through the indirect gluconeogenic route and that lactate may be a glycogenic precursor in the ovine fetus.

  14. Diamond films grown from fullerene precursors

    SciTech Connect

    Gruen, D.M.; Zuiker, C.D.; Krauss, A.R.

    1995-07-01

    Fullerene precursors have been shown to result in the growth of diamond films from argon microwave plasmas. In contradistinction to most diamond films grown using conventional methane-hydrogen mixtures, the fullerene-generated films are nanocrystalline and smooth on the nanometer scale. They have recently been shown to have friction coefficients approaching the values of natural diamond. It is clearly important to understand the development of surface morphology during film growth from fullerene precursors and to elucidate the factors leading to surface roughness when hydrogen is present in the chemical vapor deposition (CVD) gas mixtures. To achieve these goals, we are measuring surface reflectivity of diamond films growing on silicon substrates over a wide range of plasma processing conditions. A model for the interpretation of the laser interferometric data has been developed, which allows one to determine film growth rate, rms surface roughness, and bulk losses due to scattering and absorption. The rms roughness values determined by reflectivity are in good agreement with atomic force microscope (AFM) measurements. A number of techniques, including high-resolution transmission electron microscopy (HRTEM) and near-edge x-ray absorption find structure (NEXAFS) measurements, have been used to characterize the films. A mechanism for diamond-film growth involving the C{sub 2} molecule as a growth species will be presented. The mechanism is based on (1) the observation that the optical emission spectra of the fullerene- containing plasmas are dominated by the Swan bands of C{sub 2} and (2) the ability of C{sub 2} to insert directly into C-H and C-C bonds with low activation barriers, as shown by recent theoretical calculations of reactions of C{sub 2} with carbon clusters.

  15. Molecular imaging in myeloma precursor disease.

    PubMed

    Mena, Esther; Choyke, Peter; Tan, Esther; Landgren, Ola; Kurdziel, Karen

    2011-01-01

    Multiple myeloma (MM) is consistently preceded by its pre-malignant states, monoclonal gammopathy of undetermined significance (MGUS) and/or smoldering multiple myeloma (SMM). By definition, precursor conditions do not exhibit end-organ disease (anemia, hypercalcemia, renal failure, skeletal lytic lesions, or a combination of these). However, new imaging methods are demonstrating that some patients in the MGUS or SMM category are exhibiting early signs of MM. Although MGUS/SMM patients are currently defined as low-risk versus high-risk based on clinical markers, we currently lack the ability to predict the individual patient's risk of progression from MGUS/SMM to MM. Given that the presence of gross lytic bone lesions is a hallmark of MM, it is reasonable to believe that less severe bone changes defined by more sensitive imaging may be predictive of MM progression. Indeed, since bone disease is such an essential aspect of MM, imaging techniques directed at the detection of early bone lesions, have the potential to become increasingly more useful in the setting of MGUS/SMM. Current guidelines for the radiological assessment of MM still recommend the traditional skeletal survey, although its limitations are well documented, especially in early phases of the disease when radiographs can significantly underestimate the extent of bone lesions and bone marrow involvement. Newer, more advanced imaging modalities, with higher sensitivities, including whole-body low-dose computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) are being employed. Also various imaging techniques have been used to provide an assessment of bone involvement and identify extra-osseous disease. This review emphasizes the current state of the art and emerging imaging methods, which may help to better define high-risk versus low-risk MGUS/SMM. Ultimately, improved imaging could allow more tailored clinical management, and, most likely play an important role

  16. PECAM-1, apoptosis and CD34+ precursors.

    PubMed

    Zocchi, Maria R; Poggi, A

    2004-11-01

    Apoptosis is a physiological process that controls tissue homeostasis, in combination with survival signals delivered by distinct receptors that bind hormones, growth factors or extracellular matrix components. The extrinsic pathway of apoptosis is due to the triggering of death receptors and the activation of the caspase cascade; the intrinsic pathway is due to withdrawal of growth factors and mainly related to mitochondrial metabolism. The choice between survival or apoptosis, which is the result of such different integrated environmental signals, is crucial for the maintainance of bone marrow reservoir of hematopoietic precursors (HPC). CD34+ HPC can receive multiple survival signals during homing and maturation, due to different interactions with adhesion molecules expressed on endothelial and bone marrow stromal cells, proteins of the extracellular matrix and chemokines or growth factors. Among them, the signal delivered via platelet endothelial cell adhesion molecule-1 (PECAM-1) seems to contribute to the resistance of this cell population to starvation, and it is related to the maintainance of mitochondrial metabolism. Indeed, this molecule, originally described as an adhesion receptor belonging to the immunoglobulin superfamily, capable of homophilic and heterophilic interactions, turned out to be a signalling molecule, containing an immunoreceptor tyrosine-based inhibitory motifs (ITIM) within its cytoplasmic domain. In particular, it has been shown that PECAM-1 binds to different kinases and phosphatases, including the phosphatidylinositide-3-kinase that phosphorylates Akt, which, in turn can upregulate transcription and function of antiapoptotic proteins, such as Bcl-2 and Bcl-x or A1, responsible for the rescue from mitochondrial apoptosis. The possible role of PECAM-1 engagement in the prevention of starvation-induced apoptosis of HPC precursors and in the maintainance of their survival is discussed. PMID:15512808

  17. Microbial degradation of plant leachate alters lignin phenols and trihalomethane precursors

    USGS Publications Warehouse

    Pellerin, Brian A.; Hernes, Peter J.; Saraceno, John Franco; Spencer, Robert G.M.; Bergamaschi, Brian A.

    2010-01-01

    Although the importance of vascular plant-derived dissolved organic carbon (DOC) in freshwater systems has been studied, the role of leached DOC as precursors of disinfection byproducts (DBPs) during drinking water treatment is not well known. Here we measured the propensity of leachates from four crops and four aquatic macrophytes to form trihalomethanes (THMs)—a regulated class of DBPs—before and after 21 d of microbial degradation. We also measured lignin phenol content and specific UV absorbance (SUVA254) to test the assumption that aromatic compounds from vascular plants are resistant to microbial degradation and readily form DBPs. Leaching solubilized 9 to 26% of total plant carbon, which formed 1.93 to 6.72 mmol THM mol C-1 However, leachate DOC concentrations decreased by 85 to 92% over the 21-d incubation, with a concomitant decrease of 67 to 92% in total THM formation potential. Carbon-normalized THM yields in the residual DOC pool increased by 2.5 times on average, consistent with the preferential uptake of nonprecursor material. Lignin phenol concentrations decreased by 64 to 96% over 21 d, but a lack of correlation between lignin content and THM yields or SUVA254 suggested that lignin-derived compounds are not the source of increased THM precursor yields in the residual DOC pool. Our results indicate that microbial carbon utilization alters THM precursors in ecosystems with direct plant leaching, but more work is needed to identify the specific dissolved organic matter components with a greater propensity to form DBPs and affect watershed management, drinking water quality, and human health.

  18. Microbial degradation of plant leachate alters lignin phenols and trihalomethane precursors.

    PubMed

    Pellerin, Brian A; Hernes, Peter J; Saraceno, JohnFranco; Spencer, Robert G M; Bergamaschi, Brian A

    2010-01-01

    Although the importance of vascular plant-derived dissolved organic carbon (DOC) in freshwater systems has been studied, the role of leached DOC as precursors of disinfection byproducts (DBPs) during drinking water treatment is not well known. Here we measured the propensity of leachates from four crops and four aquatic macrophytes to form trihalomethanes (THMs)-a regulated class of DBPs-before and after 21 d of microbial degradation. We also measured lignin phenol content and specific UV absorbance (SUVA(254)) to test the assumption that aromatic compounds from vascular plants are resistant to microbial degradation and readily form DBPs. Leaching solubilized 9 to 26% of total plant carbon, which formed 1.93 to 6.72 mmol THM mol C(-1). However, leachate DOC concentrations decreased by 85 to 92% over the 21-d incubation, with a concomitant decrease of 67 to 92% in total THM formation potential. Carbon-normalized THM yields in the residual DOC pool increased by 2.5 times on average, consistent with the preferential uptake of nonprecursor material. Lignin phenol concentrations decreased by 64 to 96% over 21 d, but a lack of correlation between lignin content and THM yields or SUVA(254) suggested that lignin-derived compounds are not the source of increased THM precursor yields in the residual DOC pool. Our results indicate that microbial carbon utilization alters THM precursors in ecosystems with direct plant leaching, but more work is needed to identify the specific dissolved organic matter components with a greater propensity to form DBPs and affect watershed management, drinking water quality, and human health. PMID:20400590

  19. In vitro translation and processing of a precursor form of favin, a lectin from Vicia faba.

    PubMed

    Hemperly, J J; Mostov, K E; Cunningham, B A

    1982-07-10

    Favin, the glucose- and mannose-binding lectin isolated from fava (Vicia faba) beans, consists of two polypeptide chains (alpha, Mr = 5,571; beta, Mr = 20,700). Translation of fava bean mRNA in vitro in a wheat germ-derived system yields a single favin polypeptide chain of Mr = 29,000. This molecule appears to consist of a hydrophobic 29-amino acid residue signal sequence at the NH2 terminus followed by the beta chain sequence; it also includes the alpha chain sequence. These results suggest that the alpha and beta chains arise by post-translational cleavage of a single precursor polypeptide: signal-beta chain-alpha chain. The signal peptide is similar in sequence to those seen in animal and prokaryotic systems, suggesting that translocation mechanisms are highly conserved. Translation of favin mRNA in the presence of dog pancreas microsomal membranes yields at least three polypeptides in addition to the presumed precursor chain. The largest of these molecules is translocated into the lumen of the membrane vesicles and glycosylated but its signal sequence remains intact. The two other species are translocated and glycosylated, but their signal sequences have been removed; they appear to differ from each other in that one begins with the beta chain sequence and the other begins one residue after the NH2-terminal threonine of the beta chain. These three variants could reflect normal features of the processing of the favin precursor but more likely result from aberrant processing of the plant protein by dog pancreas membranes. PMID:7085653

  20. Cloning of cDNA encoding the common alpha subunit precursor molecule of pituitary glycoprotein hormones in the Australian lungfish, Neoceratodus forsteri.

    PubMed

    Arai, Y; Kubokawa, K; Ishii, S; Joss, J M

    1998-05-01

    We have isolated cDNA clones encoding a putative glycoprotein hormone alpha subunit precursor molecule from a pituitary cDNA library of the Australian lungfish (Neoceratodus forsteri) by a two-step plaque hybridization technique initially using cDNA encoding the toad glycoprotein hormone alpha subunit precursor molecule as the hybridization probe. The inserts (799 bp) of two of the isolated cDNA clones contained sequences of 5' and 3' untranslated regions, including a poly(A) stretch, and the entire coding sequence of the alpha subunit precursor molecule. The deduced amino acid sequence showed that its signal peptide consists of 24 residues and its mature protein 97 residues. In the mature protein, there is an insert of one residue (Ala) just after the 9th residue. This insert is unique to the Australian lungfish among vertebrate species studied. The amino acid sequence of the mature protein shares the common, or the same-group, amino acid residues at 9 positions with tetrapod and not actinopterygian vertebrates, while only one residue is common to some teleosts and the lungfish to the exclusion of the tetrapods. The overall sequence of the mature protein of the Australian lungfish also shares more similarity with those of tetrapods (69 to 84%) than it does with teleosts (57 to 74%). These results on the relation of the alpha subunit precursor molecule between the lungfish and other vertebrates are consistent with the recent molecular phylogenetic studies suggesting a closer relationship between lungfish and tetrapods than between lungfish and teleosts. We also found that the primary structure of the lungfish alpha subunit is slightly but significantly more similar to that of homeothermic vertebrates than to that of amphibians. This may be due to specialization of the amphibian alpha subunit molecules.

  1. Thermal Stability of Jet Fuels: Kinetics of Forming Deposit Precursors

    NASA Technical Reports Server (NTRS)

    Naegeli, David W.

    1997-01-01

    The focus of this study was on the autoxidation kinetics of deposit precursor formation in jet fuels. The objectives were: (1) to demonstrate that laser-induced fluorescence is a viable kinetic tool for measuring rates of deposit precursor formation in jet fuels; (2) to determine global rate expressions for the formation of thermal deposit precursors in jet fuels; and (3) to better understand the chemical mechanism of thermal stability. The fuels were isothermally stressed in small glass ampules in the 120 to 180 C range. Concentrations of deposit precursor, hydroperoxide and oxygen consumption were measured over time in the thermally stressed fuels. Deposit precursors were measured using laser-induced fluorescence (LIF), hydroperoxides using a spectrophotometric technique, and oxygen consumption by the pressure loss in the ampule. The expressions, I.P. = 1.278 x 10(exp -11)exp(28,517.9/RT) and R(sub dp) = 2.382 x 10(exp 17)exp(-34,369.2/RT) for the induction period, I.P. and rate of deposit precursor formation R(sub dp), were determined for Jet A fuel. The results of the study support a new theory of deposit formation in jet fuels, which suggest that acid catalyzed ionic reactions compete with free radical reactions to form deposit precursors. The results indicate that deposit precursors form only when aromatics are present in the fuel. Traces of sulfur reduce the rate of autoxidation but increase the yield of deposit precursor. Free radical chemistry is responsible for hydroperoxide formation and the oxidation of sulfur compounds to sulfonic acids. Phenols are then formed by the acid catalyzed decomposition of benzylic hydroperoxides, and deposit precursors are produced by the reaction of phenols with aldehydes, which forms a polymer similar to Bakelite. Deposit precursors appear to have a phenolic resin-like structure because the LIF spectra of the deposit precursors were similar to that of phenolic resin dissolved in TAM.

  2. Experimental determination of residual stress

    NASA Technical Reports Server (NTRS)

    Ferguson, Milton W.

    1991-01-01

    Residual stresses in finished parts have often been regarded as factors contributing to premature part failure and geometric distortions. Currently, residual stresses in welded structures and railroad components are being investigated. High residual stresses formed in welded structures due primarily to the differential contractions of the weld material as it cools and solidifies can have a profound effect on the surface performance of the structure. In railroad wheels, repeated use of the brakes causes high residual stresses in the rims which may lead to wheel failure and possible derailment. The goals of the study were: (1) to develop strategies for using x-ray diffraction to measure residual stress; (2) to subject samples of Inconel 718 to various mechanical and heat treatments and to measure the resulting stress using x-ray diffraction; and (3) to measure residual stresses in ferromagnetic alloys using magnetoacoustics.

  3. Materials recovery from shredder residues

    SciTech Connect

    Daniels, E. J.; Jody, B. J.; Pomykala, J., Jr.

    2000-07-24

    Each year, about five (5) million ton of shredder residues are landfilled in the US. Similar quantities are landfilled in Europe and the Pacific Rim. Landfilling of these residues results in a cost to the existing recycling industry and also represents a loss of material resources that are otherwise recyclable. In this paper, the authors outline the resources recoverable from typical shredder residues and describe technology that they have developed to recover these resources.

  4. Analysis of murein and murein precursors during antibiotic-induced lysis of Escherichia coli.

    PubMed Central

    Kohlrausch, U; Höltje, J V

    1991-01-01

    Lysis of Escherichia coli induced by either D-cycloserine, moenomycin, or penicillin G was monitored by studying murein metabolism. The levels of the soluble murein precursor UDP-N-acetylmuramyl-L-alanyl-D-glutamyl-m-diaminopimelyl-D-alanyl- D-alanine (UDP-MurNAc-pentapeptide) and the carrier-linked MurNAc-(pentapeptide)-pyrophosphoryl-undecaprenol as well as N-acetylglucosamine-beta-1,4-MurNAc-(pentapeptide)-pyrophosphoryl- undecaprenol varied in a specific way. In the presence of penicillin, which is known to interfere with the cross-linking of murein, the concentration of the lipid-linked precursors unexpectedly decreased before the onset of lysis, although the level of UDP-MurNAc-pentapeptide remained normal. In the case of moenomycin, which specifically blocks the formation of the murein polysaccharide strands, the lipid-linked precursors as well as UDP-MurNAc-pentapeptide accumulated as was expected. D-Cycloserine, which inhibits the biosynthesis of UDP-MurNAc-pentapeptide, consequently caused a decrease in all three precursors. The muropeptide composition of the murein showed general changes such as an increase in the unusual DL-cross bridge between two neighboring meso-diaminopimelic acid residues and, as a result of uncontrolled DL- and DD-carboxypeptidase activity, an increase in tripeptidyl and a decrease in tetrapeptidyl and pentapeptidyl moieties. The average length of the glycan strands decreased. When the glycan strands were fractionated according to length, a dramatic increase in the amount of single disaccharide units was observed not only in the presence of penicillin but also in the presence of moenomycin. This result is explained by the action of an exo-muramidase, such as the lytic transglycosylases present in E. coli. It is proposed that antibiotic-induced bacteriolysis is the result of a zipperlike splitting of the murein net by exo-muramidases locally restricted to the equatorial zone of the cell. Images PMID:2045364

  5. Frog Swarms: Earthquake Precursors or False Alarms?

    PubMed Central

    Grant, Rachel A.; Conlan, Hilary

    2013-01-01

    Simple Summary Media reports linking unusual animal behaviour with earthquakes can potentially create false alarms and unnecessary anxiety among people that live in earthquake risk zones. Recently large frog swarms in China and elsewhere have been reported as earthquake precursors in the media. By examining international media reports of frog swarms since 1850 in comparison to earthquake data, it was concluded that frog swarms are naturally occurring dispersal behaviour of juveniles and are not associated with earthquakes. However, the media in seismic risk areas may be more likely to report frog swarms, and more likely to disseminate reports on frog swarms after earthquakes have occurred, leading to an apparent link between frog swarms and earthquakes. Abstract In short-term earthquake risk forecasting, the avoidance of false alarms is of utmost importance to preclude the possibility of unnecessary panic among populations in seismic hazard areas. Unusual animal behaviour prior to earthquakes has been reported for millennia but has rarely been scientifically documented. Recently large migrations or unusual behaviour of amphibians have been linked to large earthquakes, and media reports of large frog and toad migrations in areas of high seismic risk such as Greece and China have led to fears of a subsequent large earthquake. However, at certain times of year large migrations are part of the normal behavioural repertoire of amphibians. News reports of “frog swarms” from 1850 to the present day were examined for evidence that this behaviour is a precursor to large earthquakes. It was found that only two of 28 reported frog swarms preceded large earthquakes (Sichuan province, China in 2008 and 2010). All of the reported mass migrations of amphibians occurred in late spring, summer and autumn and appeared to relate to small juvenile anurans (frogs and toads). It was concluded that most reported “frog swarms” are actually normal behaviour, probably caused by

  6. N-terminal residues regulate proteasomal degradation of AANAT.

    PubMed

    Huang, Zheping; Liu, Tiecheng; Borjigin, Jimo

    2010-04-01

    Serotonin N-acetyltransferase (AANAT) catalyzes the conversion of serotonin to N-acetylserotonin, which is the immediate precursor for formation of melatonin. Although it is known that AANAT is degraded via the proteasomal proteolysis, detailed mechanisms are not defined. In this paper, we tested the in vivo role of proteasome inhibition on AANAT activity and melatonin release and examined the amino acid residues in AANAT that contribute to the proteasome degradation. We have shown that inhibition of proteasome activities in vivo in the intact pineal gland fails to prevent the light-induced suppression of melatonin secretion. Furthermore, in cell lines stably expressing AANAT, inhibition of proteasomal proteolysis, which resulted in a large accumulation of AANAT protein, similarly failed to increase AANAT enzyme activity proportional to the amount of proteins accumulated. Site-directed mutagenesis analysis of AANAT revealed that the AANAT degradation is independent of lysine and the two surface cysteine residues. Deletion analysis of N-terminus identified the second amino acid leucine (L2) as the key residue that contributes to the proteasomal proteolysis of AANAT protein. These results suggest that rat AANAT protein is degraded via the N-end rule pathway of proteasomal proteolysis and the leucine at the N-terminus appears to be the key residue recognized by N-end rule pathway.

  7. Hydrodeoxygenation of coal using organometallic catalyst precursors

    NASA Astrophysics Data System (ADS)

    Kirby, Stephen R.

    2002-04-01

    coals. Trends within the data were similar to those reported by other authors. Based on the conclusions from both the model compound studies and the coal analysis, predictions were made of the catalyst precursors' performance in the HDO of the three selected coals. It was concluded that CoMo-T2 is a desirable catalyst precursor for the HDO of coals (particularly low-rank coals), but that an optimum set of conditions must be determined to take full advantage of its HDO ability. (Abstract shortened by UMI.)

  8. On tide-induced lagrangian residual current and residual transport: 1. Lagrangian residual current

    USGS Publications Warehouse

    Feng, Shizuo; Cheng, Ralph T.; Pangen, Xi

    1986-01-01

    Residual currents in tidal estuaries and coastal embayments have been recognized as fundamental factors which affect the long-term transport processes. It has been pointed out by previous studies that it is more relevant to use a Lagrangian mean velocity than an Eulerian mean velocity to determine the movements of water masses. Under weakly nonlinear approximation, the parameter k, which is the ratio of the net displacement of a labeled water mass in one tidal cycle to the tidal excursion, is assumed to be small. Solutions for tides, tidal current, and residual current have been considered for two-dimensional, barotropic estuaries and coastal seas. Particular attention has been paid to the distinction between the Lagrangian and Eulerian residual currents. When k is small, the first-order Lagrangian residual is shown to be the sum of the Eulerian residual current and the Stokes drift. The Lagrangian residual drift velocity or the second-order Lagrangian residual current has been shown to be dependent on the phase of tidal current. The Lagrangian drift velocity is induced by nonlinear interactions between tides, tidal currents, and the first-order residual currents, and it takes the form of an ellipse on a hodograph plane. Several examples are given to further demonstrate the unique properties of the Lagrangian residual current.

  9. Human embryonic epidermis contains a diverse Langerhans cell precursor pool.

    PubMed

    Schuster, Christopher; Mildner, Michael; Mairhofer, Mario; Bauer, Wolfgang; Fiala, Christian; Prior, Marion; Eppel, Wolfgang; Kolbus, Andrea; Tschachler, Erwin; Stingl, Georg; Elbe-Bürger, Adelheid

    2014-02-01

    Despite intense efforts, the exact phenotype of the epidermal Langerhans cell (LC) precursors during human ontogeny has not been determined yet. These elusive precursors are believed to migrate into the embryonic skin and to express primitive surface markers, including CD36, but not typical LC markers such as CD1a, CD1c and CD207. The aim of this study was to further characterize the phenotype of LC precursors in human embryonic epidermis and to compare it with that of LCs in healthy adult skin. We found that epidermal leukocytes in first trimester human skin are negative for CD34 and heterogeneous with regard to the expression of CD1c, CD14 and CD36, thus contrasting the phenotypic uniformity of epidermal LCs in adult skin. These data indicate that LC precursors colonize the developing epidermis in an undifferentiated state, where they acquire the definitive LC marker profile with time. Using a human three-dimensional full-thickness skin model to mimic in vivo LC development, we found that FACS-sorted, CD207(-) cord blood-derived haematopoietic precursor cells resembling foetal LC precursors but not CD14(+)CD16(-) blood monocytes integrate into skin equivalents, and without additional exogenous cytokines give rise to cells that morphologically and phenotypically resemble LCs. Overall, it appears that CD14(-) haematopoietic precursors possess a much higher differentiation potential than CD14(+) precursor cells.

  10. Precursors to Aggression Are Evident by 6 Months of Age

    ERIC Educational Resources Information Center

    Hay, Dale F.; Waters, Cerith S.; Perra, Oliver; Swift, Naomi; Kairis, Victoria; Phillips, Rebecca; Jones, Roland; Goodyer, Ian; Harold, Gordon; Thapar, Anita; van Goozen, Stephanie

    2014-01-01

    We tested the hypothesis that developmental precursors to aggression are apparent in infancy. Up to three informants rated 301 firstborn infants for early signs of anger, hitting and biting; 279 (93%) were assessed again as toddlers. Informants' ratings were validated by direct observation at both ages. The precursor behaviours were…

  11. Effects of rhythmic precursors on perception of stress/syllabicity

    NASA Astrophysics Data System (ADS)

    Stilp, Christian E.; Kluender, Keith R.

    2005-09-01

    Rhythmic structure is a common property of many environmental sounds including speech. Here, perceptual effects of preceding rhythmic context are assessed in experiments employing edited words for which perceived stress/syllabicity are assessed. A series of edited naturally spoken words varying perceptually from ``polite'' to ``plight,'' was created by deleting initial-vowel glottal pulses from a recording of ``polite.'' Words were identified following nonspeech precursor sequences having either trochaic (strong-weak) or iambic (weak-strong) rhythmic patterns. Precursors consisted of a harmonic spectrum (-6-dB/octave slope) filtered by four sinusoidally modulated single-pole filters. Trochaic (strong-weak) and iambic (weak-strong) rhythmic patterns were created by varying amplitude, pitch, and duration in successive segments (akin to beats) of the precursors. Precursors were comprised of two to six repetitions of these patterns. Following trochaic precursors, listeners were more likely to report hearing ``polite'' (iambic). This pattern of results indicates that perception did not assimilate to precursor pattern, consistent with rhythmic expectancy. Instead, perception shifted in a way that contrasts with precursor temporal pattern. Additional results with precursors that are more and less like speech are being conducted to further understand how auditory perception adjusts for temporal and spectral regularities. [Work supported by NIDCD.

  12. A Procedure for Identifying Precursors to Problem Behavior

    ERIC Educational Resources Information Center

    Herscovitch, Brandon; Roscoe, Eileen M.; Libby, Myrna E.; Bourret, Jason C.; Ahearn, William H.

    2009-01-01

    We describe a procedure for differentiating among potential precursor responses for use in a functional analysis. Conditional probability analysis of descriptive assessment data identified three potential precursors. Results from the indirect assessment corresponded with those obtained from the descriptive assessment. The top-ranked response…

  13. An Evaluation of Strengthening Precursors to Increase Preschooler Compliance

    ERIC Educational Resources Information Center

    Kraus, Aaron J.; Hanley, Gregory P.; Cesana, Lori L.; Eisenberg, Danielle; Jarvie, Adam C.

    2012-01-01

    We evaluated the strategy of increasing precursors to compliance on the compliance of 2 preschool boys. Modeling and differential reinforcement were used to increase specific responses to his name being called prior to the opportunity to comply with an instruction. The precursors were stopping the ongoing activity and orienting to, making eye…

  14. Topographical and Functional Properties of Precursors to Severe Problem Behavior

    ERIC Educational Resources Information Center

    Fahmie, Tara A.; Iwata, Brian A.

    2011-01-01

    A literature search identified 17 articles reporting data on 34 subjects who engaged in precursors to severe problem behavior, which we examined to identify topographical and functional characteristics. Unintelligible vocalization was the most common precursor to aggression (27%) and property destruction (29%), whereas self- or nondirected…

  15. A fission-powered interstellar precursor mission

    SciTech Connect

    Lipinski, Ronald J.; Lenard, Roger X.; Wright, Steven A. West, John L.

    1999-01-01

    An {open_quotes}interstellar precursor mission{close_quotes} lays the groundwork for eventual interstellar exploration by studying the interstellar medium and by stretching technologies that have potential application for eventual interstellar exploration. The numerous scientific goals for such a mission include generating a 3-D stellar map of our galaxy, studying Kuiper-belt and Oort cloud objects, and observing distant objects using the sun{close_quote}s gravitational lens as the primary of an enormous telescope. System equations are developed for a space tug which propels a 2500-kg scientific payload to 550 astronomical units in about 20 years. The tug to transport this payload uses electric propulsion with an lsp of 15,000 seconds and a fission reactor with a closed Brayton cycle to generate the electricity. The optimal configuration may be to thrust for only about 6 years and then coast for the remaining 14 years. This spacecraft does not require any physics breakthroughs or major advances in technology. The fission power system can be engineered and built by drawing upon known technologies developed for related systems over the past 40 years. The tug system would eventually reach 1000 a.u in 33 years, and would have adequate power to relay large amounts of data throughout its journey. {copyright} {ital 1999 American Institute of Physics.}

  16. Bacterial Cellular Materials as Precursors of Chloroform

    NASA Astrophysics Data System (ADS)

    Wang, J.; Ng, T.; Zhang, Q.; Chow, A. T.; Wong, P.

    2011-12-01

    The environmental sources of chloroform and other halocarbons have been intensively investigated because their effects of stratospheric ozone destruction and environmental toxicity. It has been demonstrated that microorganisms could facilitate the biotic generation of chloroform from natural organic matters in soil, but whether the cellular materials itself also serves as an important precursor due to photo-disinfection is poorly known. Herein, seven common pure bacterial cultures (Acinetobacter junii, Aeromonas hydrophila, Bacillus cereus, Bacillus substilis, Escherichia coli, Shigella sonnei, Staphylococcus sciuri) were chlorinated to evaluate the yields of chloroform, dibromochloromethane, dichlorobromomethane, and bromoform. The effects of bromide on these chemical productions and speciations were also investigated. Results showed that, on average, 5.64-36.42 μg-chloroform /mg-C were generated during the bacterial chlorination, in similar order of magnitude to that generated by humic acid (previously reported as 78 μg-chloroform/mg-C). However, unlike humic acid in water chlorination, chloroform concentration did not simply increase with the total organic carbon in water mixture. In the presence of bromide, the yield of brominated species responded linearly to the bromide concentration. This study provides useful information to understand the contributions of chloroform from photodisinfection processes in coastal environments.

  17. A Fission-Powered Interstellar Precursor Mission

    SciTech Connect

    Lenard, R.X.; Lipinski, R.J.; West, J.L.; Wright, S.A.

    1998-10-28

    An 'interstellar precursor mission' lays the groundwork for eventual interstellar exploration by studying the interstellar medium and by stretching technologies that have potential application for eventual interstellar exploration. The numerous scientific goals for such a mission include generating a 3-D stellar map of our galaxy, studying Kuiper-belt and Oort cloud objects, and observing distant objects using the sun's gravitational lens as the primary of an enormous telescope. System equations are developed for a space tug which propels a 2500-kg scientific payload to 550 astronomical units in about 20 years. The tug to transport this payload uses electric propulsion with an Isp of 15,000 seconds and a fission reactor with a closed Brayton cycle to genemte the electricity. The optimal configuration may be to thrust for only about 6 years and then coast for the remaining 14 pars. This spacecraft does not require any physics breakthroughs or major advances in technology. The fission power syslem can be engineered and built by drawing upon known technologies developed for relatgd systems over the past 40 years. The tug system would eventually reach 1000 a.u in 33 years, and would have adequate power to relay large amounts of data throughout its journey.

  18. PRECURSORS TO INTERSTELLAR SHOCKS OF SOLAR ORIGIN

    SciTech Connect

    Gurnett, D. A.; Kurth, W. S.; Stone, E. C.; Cummings, A. C.; Krimigis, S. M.; Decker, R. B.; Burlaga, L. F.

    2015-08-20

    On or about 2012 August 25, the Voyager 1 spacecraft crossed the heliopause into the nearby interstellar plasma. In the nearly three years that the spacecraft has been in interstellar space, three notable particle and field disturbances have been observed, each apparently associated with a shock wave propagating outward from the Sun. Here, we present a detailed analysis of the third and most impressive of these disturbances, with brief comparisons to the two previous events, both of which have been previously reported. The shock responsible for the third event was first detected on 2014 February 17 by the onset of narrowband radio emissions from the approaching shock, followed on 2014 May 13 by the abrupt appearance of intense electron plasma oscillations generated by electrons streaming outward ahead of the shock. Finally, the shock arrived on 2014 August 25, as indicated by a jump in the magnetic field strength and the plasma density. Various disturbances in the intensity and anisotropy of galactic cosmic rays were also observed ahead of the shock, some of which are believed to be caused by the reflection and acceleration of cosmic rays by the magnetic field jump at the shock, and/or by interactions with upstream plasma waves. Comparisons to the two previous weaker events show somewhat similar precursor effects, although differing in certain details. Many of these effects are very similar to those observed in the region called the “foreshock” that occurs upstream of planetary bow shocks, only on a vastly larger spatial scale.

  19. Mars MetNet Precursor Mission Status

    NASA Astrophysics Data System (ADS)

    Harri, Ari-Matti; Aleksashkin, Sergey; Guerrero, Héctor; Schmidt, Walter; Genzer, Maria; Vazquez, Luis; Haukka, Harri

    2013-04-01

    A new kind of planetary exploration mission for Mars is being developed in collaboration between the Finnish Meteorological Institute (FMI), Lavochkin Association (LA), Space Research Institute (IKI) and Institutio Nacional de Tecnica Aerospacial (INTA). The Mars MetNet mission is based on a new semi-hard landing vehicle called MetNet Lander (MNL), using an inflatable entry and descent system instead of rigid heat shields and parachutes as earlier semi-hard landing devices have used. This way the ratio of the payload mass to the overall mass is optimized. The landing impact will burrow the payload container into the Martian soil providing a more favorable thermal environment for the electronics and a suitable orientation of the telescopic boom with external sensors and the radio link antenna. It is planned to deploy several tens of MNLs on the Martian surface operating at least partly at the same time to allow meteorological network science. For the precursor mission (MMPM) intended to verify the landing concept and key technology during a real Mars mission all qualification activities are completed and the payload and system flight model components are being manufactured. The descent processes dynamic properties are monitored by a special 3-axis accelerometer combined with a 3-axis gyrometer. The data will be sent via auxiliary beacon antenna throughout the descent phase starting shortly after separation from the spacecraft. Details of the current MMPM system and payload configuration and their performance parameters will be shown.

  20. Pair fireball precursors of neutron star mergers

    NASA Astrophysics Data System (ADS)

    Metzger, Brian D.; Zivancev, Charles

    2016-10-01

    If at least one neutron star (NS) is magnetized in a binary NS merger, then the orbital motion of the conducting companion during the final inspiral induces a strong voltage and current along the magnetic field lines connecting the NSs. If a modest fraction η of the extracted electromagnetic power extracted accelerates relativistic particles, the resulting gamma-ray emission a compact volume will result in the formation of an electron-positron pair fireball. Applying a steady-state pair wind model, we quantify the detectability of the precursor fireball with gamma-ray satellites. For η ˜ 1 the gamma-ray detection horizon of Dmax ≈ 10(Bd/1014 G)3/4 Mpc is much closer than the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo horizon of 200 Mpc, unless the NS surface magnetic field strength is very large, B_d ≲ 10^{15} G. Given the quasi-isotropic nature of the emission, mergers with weaker NS fields could contribute a nearby population of short gamma-ray bursts. Power not dissipated close to the binary is carried to infinity along the open field lines by a large-scale Poynting flux. Reconnection within this outflow, well outside of the pair photosphere, provides a potential site for non-thermal emission, such as a coherent millisecond radio burst.

  1. Robotic Precursor Missions for Mars Habitats

    NASA Astrophysics Data System (ADS)

    Huntsberger, Terry; Pirjanian, Paolo; Schenker, Paul S.; Trebi-Ollennu, Ashitey; Das, Hari; Joshi, Sajay

    2000-07-01

    Infrastructure support for robotic colonies, manned Mars habitat, and/or robotic exploration of planetary surfaces will need to rely on the field deployment of multiple robust robots. This support includes such tasks as the deployment and servicing of power systems and ISRU generators, construction of beaconed roadways, and the site preparation and deployment of manned habitat modules. The current level of autonomy of planetary rovers such as Sojourner will need to be greatly enhanced for these types of operations. In addition, single robotic platforms will not be capable of complicated construction scenarios. Precursor robotic missions to Mars that involve teams of multiple cooperating robots to accomplish some of these tasks is a cost effective solution to the possible long timeline necessary for the deployment of a manned habitat. Ongoing work at JPL under the Mars Outpost Program in the area of robot colonies is investigating many of the technology developments necessary for such an ambitious undertaking. Some of the issues that are being addressed include behavior-based control systems for multiple cooperating robots (CAMPOUT), development of autonomous robotic systems for the rescue/repair of trapped or disabled robots, and the design and development of robotic platforms for construction tasks such as material transport and surface clearing.

  2. Assimilation of NAD(+) precursors in Candida glabrata.

    PubMed

    Ma, Biao; Pan, Shih-Jung; Zupancic, Margaret L; Cormack, Brendan P

    2007-10-01

    The yeast pathogen Candida glabrata is a nicotinamide adenine dinucleotide (NAD(+)) auxotroph and its growth depends on the environmental supply of vitamin precursors of NAD(+). C. glabrata salvage pathways defined in this article allow NAD(+) to be synthesized from three compounds - nicotinic acid (NA), nicotinamide (NAM) and nicotinamide riboside (NR). NA is salvaged through a functional Preiss-Handler pathway. NAM is first converted to NA by nicotinamidase and then salvaged by the Preiss-Handler pathway. Salvage of NR in C. glabrata occurs via two routes. The first, in which NR is phosphorylated by the NR kinase Nrk1, is independent of the Preiss-Handler pathway. The second is a novel pathway in which NR is degraded by the nucleosidases Pnp1 and Urh1, with a minor role for Meu1, and ultimately converted to NAD(+) via the nicotinamidase Pnc1 and the Preiss-Handler pathway. Using C. glabrata mutants whose growth depends exclusively on the external NA or NR supply, we also show that C. glabrata utilizes NR and to a lesser extent NA as NAD(+) sources during disseminated infection. PMID:17725566

  3. Bone formation on synthetic precursors of hydroxyapatite.

    PubMed

    Suzuki, O; Nakamura, M; Miyasaka, Y; Kagayama, M; Sakurai, M

    1991-05-01

    The aim of this study was to investigate the reaction of skeletal tissue to various synthetic calcium phosphate (Ca-P) compounds in vivo. Five synthetic Ca-P compounds were implanted into the subperiosteal area of the calvaria of 7-week-old BALB/c mice for one to 15 weeks. Synthetic compounds were dicalcium phosphate (DCP), octacalcium phosphate (OCP), amorphous calcium phosphate (ACP), Ca-deficient hydroxyapatite and hydroxyapatile (HA). Implanted DCP, OCP and ACP were found to be converted to apatitic phase by x-ray microdiffraction analysis using undecalcified specimens. Structure of bone was found out on all of Ca-P compounds eventually at late stage under the light microscope, but the rate of bone formation calculated from a number of experiments varied on respective synthetic Ca-P compound. It was high as 80% for DCP, OCP and ACP, but was low as 5.6% for Ca-deficient HA, and no reaction was found for HA at the stage of 3 weeks. Fine filaments and granular materials in the newly formed bone matrix were detected at 7 days around the remnants of OCP particles which already converted to apatitic phase by ultrastructural study of decalcified specimens. These structures were very similar to the components of bone nodules seen in intramembranous osteogenesis. It is postulated that the precursors of HA have an important role in intramembranous osteogenesis.

  4. Robotic Precursor Missions for Mars Habitats

    NASA Technical Reports Server (NTRS)

    Huntsberger, Terry; Pirjanian, Paolo; Schenker, Paul S.; Trebi-Ollennu, Ashitey; Das, Hari; Joshi, Sajay

    2000-01-01

    Infrastructure support for robotic colonies, manned Mars habitat, and/or robotic exploration of planetary surfaces will need to rely on the field deployment of multiple robust robots. This support includes such tasks as the deployment and servicing of power systems and ISRU generators, construction of beaconed roadways, and the site preparation and deployment of manned habitat modules. The current level of autonomy of planetary rovers such as Sojourner will need to be greatly enhanced for these types of operations. In addition, single robotic platforms will not be capable of complicated construction scenarios. Precursor robotic missions to Mars that involve teams of multiple cooperating robots to accomplish some of these tasks is a cost effective solution to the possible long timeline necessary for the deployment of a manned habitat. Ongoing work at JPL under the Mars Outpost Program in the area of robot colonies is investigating many of the technology developments necessary for such an ambitious undertaking. Some of the issues that are being addressed include behavior-based control systems for multiple cooperating robots (CAMPOUT), development of autonomous robotic systems for the rescue/repair of trapped or disabled robots, and the design and development of robotic platforms for construction tasks such as material transport and surface clearing.

  5. Precursors To Interstellar Shocks of Solar Origin

    NASA Astrophysics Data System (ADS)

    Gurnett, D. A.; Kurth, W. S.; Stone, E. C.; Cummings, A. C.; Krimigis, S. M.; Decker, R. B.; Ness, N. F.; Burlaga, L. F.

    2015-08-01

    On or about 2012 August 25, the Voyager 1 spacecraft crossed the heliopause into the nearby interstellar plasma. In the nearly three years that the spacecraft has been in interstellar space, three notable particle and field disturbances have been observed, each apparently associated with a shock wave propagating outward from the Sun. Here, we present a detailed analysis of the third and most impressive of these disturbances, with brief comparisons to the two previous events, both of which have been previously reported. The shock responsible for the third event was first detected on 2014 February 17 by the onset of narrowband radio emissions from the approaching shock, followed on 2014 May 13 by the abrupt appearance of intense electron plasma oscillations generated by electrons streaming outward ahead of the shock. Finally, the shock arrived on 2014 August 25, as indicated by a jump in the magnetic field strength and the plasma density. Various disturbances in the intensity and anisotropy of galactic cosmic rays were also observed ahead of the shock, some of which are believed to be caused by the reflection and acceleration of cosmic rays by the magnetic field jump at the shock, and/or by interactions with upstream plasma waves. Comparisons to the two previous weaker events show somewhat similar precursor effects, although differing in certain details. Many of these effects are very similar to those observed in the region called the “foreshock” that occurs upstream of planetary bow shocks, only on a vastly larger spatial scale.

  6. Precursors to Interstellar Shocks of Solar Origin

    NASA Astrophysics Data System (ADS)

    Gurnett, D. A.; Kurth, W. S.; Stone, E. C.; Cummings, A. C.; Krimigis, S. M.; Decker, R. B.; Ness, N. F.; Burlaga, L. F.

    2015-12-01

    On or about 2012 August 25, the Voyager 1 spacecraft crossed the heliopause into the nearby interstellar plasma. In the nearly three years that the spacecraft has been in interstellar space, three notable particle and field disturbances have been observed, each apparently associated with a shock wave propagating outward from the Sun. Here, we present a detailed analysis of the third and most impressive of these disturbances, with brief comparisons to the two previous events, both of which have been previously reported. The shock responsible for the third event was first detected on 2014 February 17 by the onset of narrowband radio emissions from the approaching shock, followed on 2014 May 13 by the abrupt appearance of intense electron plasma oscillations generated by electrons streaming outward ahead of the shock. Finally, the shock arrived on 2014 August 25, as indicated by a jump in the magnetic field strength and the plasma density. Various disturbances in the intensity and anisotropy of galactic cosmic rays were also observed ahead of the shock, some of which are believed to be caused by the reflection and acceleration of cosmic rays by the magnetic field jump at the shock, and/or by interactions with upstream plasma waves. Comparisons to the two previous weaker events show somewhat similar precursor effects, although differing in certain details. Many of these effects are very similar to those observed in the region called the "foreshock" that occurs upstream of planetary bow shocks, only on a vastly larger spatial scale.

  7. Cellular Metabolism of Unnatural Sialic Acid Precursors

    PubMed Central

    Pham, Nam D.; Fermaintt, Charles S.; Rodriguez, Andrea C.; McCombs, Janet E.; Nischan, Nicole; Kohler, Jennifer J.

    2015-01-01

    Carbohydrates, in addition to their metabolic functions, serve important roles as receptors, ligands, and structural molecules for diverse biological processes. Insight into carbohydrate biology and mechanisms has been aided by metabolic oligosaccharide engineering (MOE). In MOE, unnatural carbohydrate analogs with novel functional groups are incorporated into cellular glycoconjugates and used to probe biological systems. While MOE has expanded knowledge of carbohydrate biology, limited metabolism of unnatural carbohydrate analogs restricts its use. Here we assess metabolism of SiaDAz, a diazirine-modified analog of sialic acid, and its cell-permeable precursor, Ac4ManNDAz. We show that the efficiency of Ac4ManNDAz and SiaDAz metabolism depends on cell type. Our results indicate that different cell lines can have different metabolic roadblocks in the synthesis of cell surface SiaDAz. These findings point to roles for promiscuous intracellular esterases, kinases, and phosphatases during unnatural sugar metabolism and provide guidance for ways to improve MOE. PMID:25957566

  8. The Amyloid Precursor Protein Controls PIKfyve Function

    PubMed Central

    Balklava, Zita; Niehage, Christian; Currinn, Heather; Mellor, Laura; Guscott, Benjamin; Poulin, Gino; Hoflack, Bernard; Wassmer, Thomas

    2015-01-01

    While the Amyloid Precursor Protein (APP) plays a central role in Alzheimer’s disease, its cellular function still remains largely unclear. It was our goal to establish APP function which will provide insights into APP's implication in Alzheimer's disease. Using our recently developed proteo-liposome assay we established the interactome of APP's intracellular domain (known as AICD), thereby identifying novel APP interactors that provide mechanistic insights into APP function. By combining biochemical, cell biological and genetic approaches we validated the functional significance of one of these novel interactors. Here we show that APP binds the PIKfyve complex, an essential kinase for the synthesis of the endosomal phosphoinositide phosphatidylinositol-3,5-bisphosphate. This signalling lipid plays a crucial role in endosomal homeostasis and receptor sorting. Loss of PIKfyve function by mutation causes profound neurodegeneration in mammals. Using C. elegans genetics we demonstrate that APP functionally cooperates with PIKfyve in vivo. This regulation is required for maintaining endosomal and neuronal function. Our findings establish an unexpected role for APP in the regulation of endosomal phosphoinositide metabolism with dramatic consequences for endosomal biology and important implications for our understanding of Alzheimer's disease. PMID:26125944

  9. The Amyloid Precursor Protein Controls PIKfyve Function.

    PubMed

    Balklava, Zita; Niehage, Christian; Currinn, Heather; Mellor, Laura; Guscott, Benjamin; Poulin, Gino; Hoflack, Bernard; Wassmer, Thomas

    2015-01-01

    While the Amyloid Precursor Protein (APP) plays a central role in Alzheimer's disease, its cellular function still remains largely unclear. It was our goal to establish APP function which will provide insights into APP's implication in Alzheimer's disease. Using our recently developed proteo-liposome assay we established the interactome of APP's intracellular domain (known as AICD), thereby identifying novel APP interactors that provide mechanistic insights into APP function. By combining biochemical, cell biological and genetic approaches we validated the functional significance of one of these novel interactors. Here we show that APP binds the PIKfyve complex, an essential kinase for the synthesis of the endosomal phosphoinositide phosphatidylinositol-3,5-bisphosphate. This signalling lipid plays a crucial role in endosomal homeostasis and receptor sorting. Loss of PIKfyve function by mutation causes profound neurodegeneration in mammals. Using C. elegans genetics we demonstrate that APP functionally cooperates with PIKfyve in vivo. This regulation is required for maintaining endosomal and neuronal function. Our findings establish an unexpected role for APP in the regulation of endosomal phosphoinositide metabolism with dramatic consequences for endosomal biology and important implications for our understanding of Alzheimer's disease. PMID:26125944

  10. Fungicide residues in strawberry processing.

    PubMed

    Will, F; Krüger, E

    1999-03-01

    The fate of three fungicides (dichlofluanid, procymidone, and iprodione) applied under field conditions was studied during strawberry processing to juice, wine, and jam. An untreated control was compared to raw material treated with fungicides according to recommended doses and to a sample with 6-fold higher application rates. The highest residue values were found in the pomace after pressing. Residue values in readily produced juices and fruit wines were very low and did not exceed legally required maximum residue levels. Generally, processing steps such as pressing and clarification diminished fungicide residues from 50 to 100%. If the whole fruit is processed, as in fruit preparations or jam, the residue levels remain higher due to missing processing steps. PMID:10552381

  11. Precursor of kunitz trypsin inhibitor in soybean seeds

    SciTech Connect

    McGrain, A.; Chen, J.; Tan-Wilson, A. )

    1990-05-01

    Kunitz soybean trypsin inhibitor (KSTI) appears to be synthesized in precursor form which is converted by proteolytic digestion to the mature form of KSTI. Two forms of anti-cross-reacting material are evident when Western blots of extracts of developing seeds are analyzed. The precursor form increases to maximum levels as seed lengths increase to 11 mm. As the seed matures to 13 mm and turns yellow, precursor levels decrease while mature KSTI levels increase. The conversion of precursor to mature form could be demonstrated in vitro in seed extracts. The conversion could also be demonstrated in excised seeds pulse-labeled with ({sup 14}C)-leucine as loss of radioactivity from the precursor and appearance in the mature KSTI form.

  12. Stable tRNA precursors in HeLa cells.

    PubMed Central

    Harada, F; Matsubara, M; Kato, N

    1984-01-01

    Two tRNA precursors were isolated from 32P-labeled or unlabeled HeLa cells by two dimensional polyacrylamide gel electrophoresis, and were sequenced. These were the precursors of tRNAMet and tRNALeu, and both contained four extra nucleotides including 5'-triphosphates at their 5'-end and nine extra nucleotides including oligo U at their 3'-end. These RNAs are the first naturally occurring tRNA precursors from higher eukaryotes whose sequences have been determined. In these molecules, several modified nucleosides such as m2G, t6A and ac4C in mature tRNAs were undermodified. Two additional hydrogen bonds were formed in the clover leaf structures of these tRNA precursors. These extra hydrogen bonds may be responsible for the stabilities of these tRNA precursors. Images PMID:6514577

  13. Experimental analysis of precursors to severe problem behavior.

    PubMed

    Fritz, Jennifer N; Iwata, Brian A; Hammond, Jennifer L; Bloom, Sarah E

    2013-01-01

    Some individuals engage in both mild and severe forms of problem behavior. Research has shown that when mild behaviors precede severe behaviors (i.e., the mild behaviors serve as precursors), they can (a) be maintained by the same source of reinforcement as severe behavior and (b) reduce rates of severe behavior observed during assessment. In Study 1, we developed an objective checklist to identify precursors via videotaped trials for 16 subjects who engaged in problem behavior and identified at least 1 precursor for every subject. In Study 2, we conducted separate functional analyses of precursor and severe problem behaviors for 8 subjects, and obtained correspondence between outcomes in 7 cases. In Study 3, we evaluated noncontingent reinforcement schedule thinning plus differential reinforcement of alternative behavior to reduce precursors, increase appropriate behavior, and maintain low rates of severe behavior during 3 treatment analyses for 2 subjects. Results showed that this treatment strategy was effective for behaviors maintained by positive and negative reinforcement.

  14. Apparatus for silicon nitride precursor solids recovery

    DOEpatents

    Crosbie, Gary M.; Predmesky, Ronald L.; Nicholson, John M.

    1995-04-04

    Method and apparatus are provided for collecting reaction product solids entrained in a gaseous outflow from a reaction situs, wherein the gaseous outflow includes a condensable vapor. A condensate is formed of the condensable vapor on static mixer surfaces within a static mixer heat exchanger. The entrained reaction product solids are captured in the condensate which can be collected for further processing, such as return to the reaction situs. In production of silicon imide, optionally integrated into a production process for making silicon nitride caramic, wherein reactant feed gas comprising silicon halide and substantially inert carrier gas is reacted with liquid ammonia in a reaction vessel, silicon imide reaction product solids entrained in a gaseous outflow comprising residual carrier gas and vaporized ammonia can be captured by forming a condensate of the ammonia vapor on static mixer surfaces of a static mixer heat exchanger.

  15. Method for silicon nitride precursor solids recovery

    DOEpatents

    Crosbie, Gary M.; Predmesky, Ronald L.; Nicholson, John M.

    1992-12-15

    Method and apparatus are provided for collecting reaction product solids entrained in a gaseous outflow from a reaction situs, wherein the gaseous outflow includes a condensable vapor. A condensate is formed of the condensable vapor on static mixer surfaces within a static mixer heat exchanger. The entrained reaction product solids are captured in the condensate which can be collected for further processing, such as return to the reaction situs. In production of silicon imide, optionally integrated into a production process for making silicon nitride caramic, wherein reactant feed gas comprising silicon halide and substantially inert carrier gas is reacted with liquid ammonia in a reaction vessel, silicon imide reaction product solids entrained in a gaseous outflow comprising residual carrier gas and vaporized ammonia can be captured by forming a condensate of the ammonia vapor on static mixer surfaces of a static mixer heat exchanger.

  16. Crystal Structure of a Molybdopterin Synthase-Precursor Z Complex: Insight into its Sulfur Transfer Mechanism and Its Role in Molybdenum Cofactor Dificiency

    SciTech Connect

    Daniels,J.; Wuebbens, M.; Rajagopalan, K.; Schindelin, H.

    2008-01-01

    In almost all biological life forms, molybdenum and tungsten are coordinated by molybdopterin (MPT), a tricyclic pyranopterin containing a cis-dithiolene group. Together, the metal and the pterin moiety form the redox reactive molybdenum cofactor (Moco). Mutations in patients with deficiencies in Moco biosynthesis usually occur in the enzymes catalyzing the first and second steps of biosynthesis, leading to the formation of precursor Z and MPT, respectively. The second step is catalyzed by the heterotetrameric MPT synthase protein consisting of two large (MoaE) and two small (MoaD) subunits with the MoaD subunits located at opposite ends of a central MoaE dimer. Previous studies have determined that the conversion of the sulfur- and metal-free precursor Z to MPT by MPT synthase involves the transfer of sulfur atoms from a C-terminal MoaD thiocarboxylate to the C-1' and C-2' positions of precursor Z. Here, we present the crystal structures of non-thiocarboxylated MPT synthase from Staphylococcus aureus in its apo form and in complex with precursor Z. A comparison of the two structures reveals conformational changes in a loop that participates in interactions with precursor Z. In the complex, precursor Z is bound by strictly conserved residues in a pocket at the MoaE dimer interface in close proximity of the C-terminal glycine of MoaD. Biochemical evidence indicates that the first dithiolene sulfur is added at the C-2' position.

  17. GroEL-assisted and -unassisted refolding of mature and precursor adrenodoxin: the role of the precursor sequence.

    PubMed

    Bera, A K; Bernhardt, R

    1999-07-01

    We have performed refolding studies on a [2Fe-2S] protein, adrenodoxin (Adx), and its precursor form, preadrenodoxin. In vitro, mature Adx is expressed as a soluble active form in Escherichia coli, but precursor Adx is expressed in inclusion bodies. Both mature and precursor Adx refolded spontaneously from their denatured forms and the recovery levels of enzyme activities were 40 and 37% for mature and precursor Adx, respectively. Furthermore, the interaction between GroEL- and Gdn-HCl-denatured mature and precursor forms was investigated. In the case of mature Adx, the activity was increased in the presence of either GroEL, GroES, or bovine serum albumin and the refolding of mature Adx is a nonspecific process. However, the GroEL-mediated reaction is specific for precursor Adx under the experimental conditions used here. A higher electron transfer activity is obtained after ATP addition to the GroEL-containing refolding mixture, and GroEL-precursor complexes were found by gel chromatography studies. Our observation suggests that the small single-domain protein Adx (mature form) folded independently of the chaperonin GroEL. The contribution of the chaperonin complexes to the folding is toward the aggregation-sensitive precursor Adx, which in vitro folded 1.3- to 1.4-fold slower than mature Adx. This demonstrates that the presequence is responsible for the formation of inclusion bodies and for the in vitro recognition motif for GroEL binding.

  18. PRECOMBUSTION REMOVAL OF HAZARDOUS AIR POLLUTANT PRECURSORS

    SciTech Connect

    Unknown

    2000-10-09

    In response to growing environmental concerns reflected in the 1990 Clean Air Act Amendment (CAAA), the United States Department of Energy (DOE) sponsored several research and development projects in late 1995 as part of an initiative entitled Advanced Environmental Control Technologies for Coal-Based Power Systems. The program provided cost-shared support for research and development projects that could accelerate the commercialization of affordable, high-efficiency, low-emission, coal-fueled electric generating technologies. Clean coal technologies developed under this program would serve as prototypes for later generations of technologies to be implemented in the industrial sector. In order to identify technologies with the greatest potential for commercial implementation, projects funded under Phase I of this program were subject to competitive review by DOE before being considered for continuation funding under Phase II. One of the primary topical areas identified under the DOE initiative relates to the development of improved technologies for reducing the emissions of air toxics. Previous studies have suggested that many of the potentially hazardous air pollutant precursors (HAPPs) occur as trace elements in the mineral matter of run-of-mine coals. As a result, these elements have the potential to be removed prior to combustion at the mine site by physical coal cleaning processes (i.e., coal preparation). Unfortunately, existing coal preparation plants are generally limited in their ability to remove HAPPs due to incomplete liberation of the mineral matter and high organic associations of some trace elements. In addition, existing physical coal cleaning plants are not specifically designed or optimized to ensure that high trace element rejections may be achieved.

  19. Precursor Science for the Terrestrial Planet Finder

    NASA Technical Reports Server (NTRS)

    Lawson, P. R. (Editor); Unwin, S. C. (Editor); Beichman, C. A. (Editor)

    2004-01-01

    This document outlines a path for the development of the field of extrasolar planet research, with a particular emphasis on the goals of the Terrestrial Planet Finder (TPF). Over the past decade, a new field of research has developed, the study of extrasolar planetary systems, driven by the discovery of massive planets around nearby stars. The planet count now stands at over 130. Are there Earth-like planets around nearby stars? Might any of those planets be conducive to the formation and maintenance of life? These arc the questions that TPF seeks to answer. TPF will be implemented as a suite of two space observatories, a 6-m class optical coronagraph, to be launched around 20 14, and a formation flying mid-infrared interferometer, to be launched sometime prior to 2020. These facilities will survey up to 165 or more nearby stars and detect planets like Earth should they be present in the 'habitable zone' around each star. With observations over a broad wavelength range, TPF will provide a robust determination of the atmospheric composition of planets to assess habitability and the presence of life. At this early stage of TPF's development, precursor observational and theoretical programs are essential to help define the mission, to aid our understanding of the planets that TPF could discover, and to characterize the stars that TPF will eventually study. This document is necessarily broad in scope because the significance of individual discoveries is greatly enhanced when viewed in thc context of the field as a whole. This document has the ambitious goal of taking us from our limited knowledge today, in 2004, to the era of TPF observations in the middle of the next decade. We must use the intervening years wisely. This document will be reviewed annually and updated as needed. The most recent edition is available online at http://tpf.jpl.nasa.gov/ or by email request to lawson@hucy.jpl.nasa.gov

  20. Molecular precursor routes to transition metal sulfides

    NASA Astrophysics Data System (ADS)

    Dinnage, Christopher Walker

    This thesis is primarily concerned with the synthesis of homoleptic early transition meta thiolates and the subsequent preparation of bulk and thin-film metal disulfides from these compounds. Chapter 1 gives an introduction into the properties, preparation procedures and uses of bulk and thin-film transition metal disulfides as well as giving an overview of early transition metal thiolates synthesied so far in the literature (for titanium, zirconium, tantalum and niobium). Chapter 2 is concerned with the synthesis of a number of ionic and neutral transition metal thiolates. The main synthetic methodologies discussed in this chapter include substitution reactions of transition metal amides and alkyls with thiols, salt metathesis reactions of transition metal chlorides with alkali metal thiolates or with a base / thiol and the use of Grignard reagents. Chapter 3 discusses the preparation of bulk transition metal disulfides using the thiolates prepared in the previous chapter via a thio "sol-gel" route. The preparation of a range of bulk metal and mixed-metal disulfides using transition metal chlorides and hexamethyldisilathiane is also discussed in this chapter. Finally, chapter 4 is concerned with the attempted preparation of thin-films of some transition metal disulfides. Decomposition studies of some of the thiolates prepared in chapter 2 are discussed using thermal gravimetric analysis. Vapour-phase deposition studies are also explored in order to test the potential of the transition metal thiolates as precursors to the disulfides. Experiments using low-pressure chemical vapour deposition and aerosol-assisted chemical vapour deposition are also described.

  1. The reliability of radon as seismic precursor

    NASA Astrophysics Data System (ADS)

    Emilian Toader, Victorin; Moldovan, Iren Adelina; Ionescu, Constantin; Marmureanu, Alexandru

    2016-04-01

    Our multidisciplinary network (AeroSolSys) located in Vrancea (Curvature Carpathian Mountains) includes radon concentration monitoring in five stations. We focus on lithosphere and near surface low atmosphere phenomena using real-time information about seismicity, + / - ions, clouds, solar radiation, temperature (air, ground), humidity, atmospheric pressure, wind speed and direction, telluric currents, variations of the local magnetic field, infrasound, variations of the atmospheric electrostatic field, variations in the earth crust with inclinometers, electromagnetic activity, CO2 concentration, ULF radio wave propagation, seismo-acoustic emission, animal behavior. The main purpose is to inform the authorities about risk situation and update hazard scenarios. The radon concentration monitoring is continuously with 1 hour or 3 hours sample rate in locations near to faults in an active seismic zone characterized by intermediate depth earthquakes. Trigger algorithms include standard deviation, mean and derivative methods. We correlate radon concentration measurements with humidity, temperature and atmospheric pressure from the same equipment. In few stations we have meteorological information, too. Sometime the radon concentration has very high variations (maxim 4535 Bq/m3 from 106 Bq/m3) in short time (1 - 2 days) without being accompanied by an important earthquake. Generally the cause is the high humidity that could be generated by tectonic stress. Correlation with seismicity needs information from minimum 6 month in our case. For 10605 hours, 618 earthquakes with maxim magnitude 4.9 R, we have got radon average 38 Bq/m3 and exposure 408111 Bqh/m3 in one station. In two cases we have correlation between seismicity and radon concentration. In other one we recorded high variation because the location was in an area with multiple faults and a river. Radon can be a seismic precursor but only in a multidisciplinary network. The anomalies for short or long period of

  2. A conserved amino acid residue critical for product and substrate specificity in plant triterpene synthases.

    PubMed

    Salmon, Melissa; Thimmappa, Ramesha B; Minto, Robert E; Melton, Rachel E; Hughes, Richard K; O'Maille, Paul E; Hemmings, Andrew M; Osbourn, Anne

    2016-07-26

    Triterpenes are structurally complex plant natural products with numerous medicinal applications. They are synthesized through an origami-like process that involves cyclization of the linear 30 carbon precursor 2,3-oxidosqualene into different triterpene scaffolds. Here, through a forward genetic screen in planta, we identify a conserved amino acid residue that determines product specificity in triterpene synthases from diverse plant species. Mutation of this residue results in a major change in triterpene cyclization, with production of tetracyclic rather than pentacyclic products. The mutated enzymes also use the more highly oxygenated substrate dioxidosqualene in preference to 2,3-oxidosqualene when expressed in yeast. Our discoveries provide new insights into triterpene cyclization, revealing hidden functional diversity within triterpene synthases. They further open up opportunities to engineer novel oxygenated triterpene scaffolds by manipulating the precursor supply. PMID:27412861

  3. A conserved amino acid residue critical for product and substrate specificity in plant triterpene synthases

    PubMed Central

    Salmon, Melissa; Thimmappa, Ramesha B.; Minto, Robert E.; Melton, Rachel E.; O’Maille, Paul E.; Hemmings, Andrew M.; Osbourn, Anne

    2016-01-01

    Triterpenes are structurally complex plant natural products with numerous medicinal applications. They are synthesized through an origami-like process that involves cyclization of the linear 30 carbon precursor 2,3-oxidosqualene into different triterpene scaffolds. Here, through a forward genetic screen in planta, we identify a conserved amino acid residue that determines product specificity in triterpene synthases from diverse plant species. Mutation of this residue results in a major change in triterpene cyclization, with production of tetracyclic rather than pentacyclic products. The mutated enzymes also use the more highly oxygenated substrate dioxidosqualene in preference to 2,3-oxidosqualene when expressed in yeast. Our discoveries provide new insights into triterpene cyclization, revealing hidden functional diversity within triterpene synthases. They further open up opportunities to engineer novel oxygenated triterpene scaffolds by manipulating the precursor supply. PMID:27412861

  4. Safety assessment of drug residues

    SciTech Connect

    Jackson, B.A.

    1980-05-15

    The safety assessment of drug residues is part of the process for defining the conditions for the safe use of drugs in food-producing animals. The information needed to assess the safety of drug residues is provided by chemical and toxicity tests. Toxicity tests are conducted to identify the type of effect produced and to determine the exposure concentrations that would be expected not to produce the effect. These tests include acute, subacute, and chronic toxicity tests, as well as reproduction studies and other special tests. The results are used to find an acceptable daily intake for drug residues that can be used to set a tolerance.

  5. Precursor-directed biosynthesis of novel triketide lactones.

    PubMed

    Regentin, Rika; Kennedy, Jonathan; Wu, Nicholas; Carney, John R; Licari, Peter; Galazzo, Jorge; Desai, Ruchir

    2004-01-01

    Precursor-directed biosynthesis was used to produce different triketide lactones (R-TKLs) in a fermentation process. Plasmids expressing engineered versions of the first subunit of 6-deoxyerythronolide B synthase (DEBS1) fused to the terminal DEBS thioesterase (TE) were introduced into three different Streptomyces strains. The DEBS1 protein fused to TE had either an inactivated ketosynthase domain (KS1 degrees ) or a partial DEBS1 lacking module 1 but containing module 2 (M2+TE). Different synthetic precursors were examined for their effect on R-TKL production. An overproducing strain of S. coelicolor expressing the M2+TE protein was found to be best for production of R-TKLs. Racemic precursors were as effective as enantiomerically pure precursors in the fermentation process. The R group on the precursor significantly affected titer (propyl > chloromethyl > vinyl). The R-TKLs were unstable in fermentation broth at pH 6-8. A two-phase fermentation with a pH shift was implemented to stabilize the products. The fermentation pH initially was controlled at optimal values for cell growth (pH 6.5) and then shifted to 5.5 during production. This doubled peak titers and stabilized the product. Finally, the concentration of synthetic precursor in the fermentation was optimized to improve production. A maximum titer of 500 mg/L 5-chloromethyl-TKL was obtained using 3.5 g/L precursor. PMID:14763833

  6. Clustering chlorine reactivity of haloacetic acid precursors in inland lakes.

    PubMed

    Zeng, Teng; Arnold, William A

    2014-01-01

    Dissolved organic matter (DOM) represents the major pool of organic precursors for harmful disinfection byproducts, such as haloacetic acids (HAAs), formed during drinking water chlorination, but much of it remains molecularly uncharacterized. Knowledge of model precursors is thus a prerequisite for understanding the more complex whole water DOM. The utility of HAA formation potential data from model DOM precursors, however, is limited due to the lack of comparability to water samples. In this study, the formation kinetics of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), the two predominant HAA species, were delineated upon chlorination of seventeen model DOM precursors and sixty-eight inland lake water samples collected from the Upper Midwest region of the United States. Of particular interest was the finding that the DCAA and TCAA formation rate constants could be grouped into four statistically distinct clusters reflecting the core structural features of model DOM precursors (i.e., non-β-diketone aliphatics, β-diketone aliphatics, non-β-diketone phenolics, and β-diketone phenolics). A comparative approach built upon hierarchical cluster analysis was developed to gain further insight into the chlorine reactivity patterns of HAA precursors in inland lake waters as defined by the relative proximity to four model precursor clusters. This work highlights the potential for implementing an integrated kinetic-clustering approach to constrain the chlorine reactivity of DOM in source waters.

  7. Combinatorial Rules of Precursor Specification Underlying Olfactory Neuron Diversity

    PubMed Central

    Li, Qingyun; Ha, Tal Soo; Okuwa, Sumie; Wang, Yiping; Wang, Qian; Millard, S. Sean; Smith, Dean P.; Volkan, Pelin Cayirlioglu

    2015-01-01

    Summary Background Sensory neuron diversity ensures optimal detection of the external world and is a hallmark of sensory systems. An extreme example is the olfactory system, as individual olfactory receptor neurons (ORNs) adopt unique sensory identities by typically expressing a single receptor gene from a large genomic repertoire. In Drosophila, about 50 different ORN classes are generated from a field of precursor cells, giving rise to spatially restricted and distinct clusters of ORNs on the olfactory appendages. Developmental strategies spawning ORN diversity from an initially homogeneous population of precursors are largely unknown. Results Here we unravel the nested and binary logic of the combinatorial code that patterns the decision landscape of precursor states underlying ORN diversity in the Drosophila olfactory system. The transcription factor Rotund (Rn) is a critical component of this code that is expressed in a subset of ORN precursors. Addition of Rn to preexisting transcription factors that assign zonal identities to precursors on the antenna subdivides each zone and almost exponentially increases ORN diversity by branching off novel precursor fates from default ones within each zone. In rn mutants, rn-positive ORN classes are converted to rn-negative ones in a zone-specific manner. Conclusions We provide a model describing how nested and binary changes in combinations of transcription factors could coordinate and pattern a large number of distinct precursor identities within a population to modulate the level of ORN diversity during development and evolution. PMID:24268416

  8. Hafnium carbide structural foams synthesized from polymer precursors

    NASA Astrophysics Data System (ADS)

    Fan, Haibo

    2005-11-01

    A study was conducted to investigate a new low cost approach to produce Hafnium Carbide (HfC) structural foams through the thermolysis and pyrolysis of polymer precursors. Hafnium carbide has a melting point of over 3900 °C, the highest melting point of any known binary alloy. HfC structural foams can be fabricated into high temperature components or used as a thermal insulation material. Current available methods for creating HfC structural foams are time consuming, expensive or the material produced lacks mechanical strength. The objectives of this research were to produce HfC foam through the thermolysis and pyrolysis of Hf containing polymer mixture, optimize the properties of the HfC foam, and develop a knowledge base of acceptable process parameters. With the proposed method, HfC foam was produced by mixing a hafnium containing Macromolecular Metal Complex (MMC) and carbon source polymers, followed by heat treating the mixture under vacuum. XRD analysis showed that the produced foam was largely composed of HfC, with small amounts of hafnium oxide. The foam total porosity was measured to be over 85%. The HfC lattice parameter was found to range from 0.4613 nm to 0.4647 nm. The HfC conversion mechanism was investigated using Residual Gas Analysis, where it was observed that polymer decomposition occurred from 80 through 550 °C and HfC conversion started around 1100 °C. The HfC foam mechanical properties and microstructure were improved by optimizing the process methods and parameters. The initial research yielded an HfC foam with a compression strength of 15.16 +/- 4.66 MPa and evenly distributed foam cells with diameter sizes up to 50 mum. Continued research showed that HfC foams with total porosity of about 85% (density 1.9g/cm 3), and a foam compression strength of 212 +/- 25MPa were achievable. The proposed methodology for synthesizing HfC foam was found to be simple, inexpensive and require less production time. The process can be controlled to produce

  9. Methods for forming particles from single source precursors

    DOEpatents

    Fox, Robert V.; Rodriguez, Rene G.; Pak, Joshua

    2011-08-23

    Single source precursors are subjected to carbon dioxide to form particles of material. The carbon dioxide may be in a supercritical state. Single source precursors also may be subjected to supercritical fluids other than supercritical carbon dioxide to form particles of material. The methods may be used to form nanoparticles. In some embodiments, the methods are used to form chalcopyrite materials. Devices such as, for example, semiconductor devices may be fabricated that include such particles. Methods of forming semiconductor devices include subjecting single source precursors to carbon dioxide to form particles of semiconductor material, and establishing electrical contact between the particles and an electrode.

  10. Surface doping of nitrogen atoms on graphene via molecular precursor

    SciTech Connect

    Hong, Guo; Wu, Qi-Hui; Ren, Jianguo; Xu, Tingting; Wang, Chundong; Zhang, Wenjun; Lee, Shuit-Tong

    2013-02-04

    Surface doping can be a powerful way to modify the electronic properties of graphene with the unique potential to retain the excellent pristine properties of graphene. Here, we report an atomic surface doping method for graphene via dissociation of adsorbed precursor molecules of tetrafluorotetracyanoquinodimethane (F{sub 4}-TCNQ) induced by hydrogen plasma treatment. Significantly, the location of the dopant N atoms can be pre-determined by the location and orientation of the F{sub 4}-TCNQ molecule precursor on graphene, leading in principle to site-selective doping. Furthermore, the molecular precursor is stable under ambient conditions, satisfying an important consideration for patterning processes.

  11. An evaluation of strengthening precursors to increase preschooler compliance.

    PubMed

    Kraus, Aaron J; Hanley, Gregory P; Cesana, Lori L; Eisenberg, Danielle; Jarvie, Adam C

    2012-01-01

    We evaluated the strategy of increasing precursors to compliance on the compliance of 2 preschool boys. Modeling and differential reinforcement were used to increase specific responses to his name being called prior to the opportunity to comply with an instruction. The precursors were stopping the ongoing activity and orienting to, making eye contact with, and saying "yes" to the instructor. High levels of precursors occurred during treatment, and increases in compliance also were observed, even though the consequences for compliance and noncompliance did not change.

  12. AN EVALUATION OF STRENGTHENING PRECURSORS TO INCREASE PRESCHOOLER COMPLIANCE

    PubMed Central

    Kraus, Aaron J; Hanley, Gregory P; Cesana, Lori L; Eisenberg, Danielle; Jarvie, Adam C

    2012-01-01

    We evaluated the strategy of increasing precursors to compliance on the compliance of 2 preschool boys. Modeling and differential reinforcement were used to increase specific responses to his name being called prior to the opportunity to comply with an instruction. The precursors were stopping the ongoing activity and orienting to, making eye contact with, and saying “yes” to the instructor. High levels of precursors occurred during treatment, and increases in compliance also were observed, even though the consequences for compliance and noncompliance did not change. PMID:22403455

  13. Enhanced identification of peptides lacking basic residues by LC-ESI-MS/MS analysis of singly charged peptides.

    PubMed

    Biniossek, Martin L; Schilling, Oliver

    2012-05-01

    Peptide sequences lacking basic residues (arginine, lysine, or histidine, referred to as "base-less") are of particular importance in proteomic experiments targeting protein C-termini or employing nontryptic proteases such as GluC or chymotrypsin. We demonstrate enhanced identification of base-less peptides by focused analysis of singly charged precursors in liquid chromatography (LC) electrospray ionization (ESI) tandem mass spectrometry (MS/MS). Singly charged precursors are often excluded from fragmentation and sequence analysis in LC-MS/MS. We generated different pools of base-less and base-containing peptides by tryptic and nontryptic digestion of bacterial proteomes. Focused LC-MS/MS analysis of singly charged precursor ions yielded predominantly base-less peptide identifications. Similar numbers of base-less peptides were identified by LC-MS/M Sanalysis targeting multiply charged precursors. There was little redundancy between the base-less sequences derived by both MS/MS schemes. In the present experimental outcome, additional LC-MS/MS analysis of singly charged precursors substantially increased the identification rate of base-less sequences derived from multiply charged precursors. In conclusion, LC-MS/MS based identification of base-less peptides is substantially enhanced by additional focused analysis of singly charged precursors.

  14. [Felice Fontana precursor of neurosciences (author's transl)].

    PubMed

    Disertori, B; Piazza, M

    1981-01-01

    The A.A. insert the life and work of the naturalist and chemist Felice Fontana, born in Pomarolo (Trentino), in the frame of 18th century sciences, beside other great names of that century like Carolus Linnaeus, Réaumur, von Haller, Spallanzani, Morgagni, Priestley and Lavoisier. In the field of general biology, the discovery of nucleus and nucleolus and consequently the discovery of the eukaryotic cell, as we say in our days, in his, as well as the one of anabiosis. The A.A. enucleate and analyse the contributions of Fontana to the neurosciences; he has discovered the axon and the myelinic sheath half century before Remak and Purknije; he found out that the white matter of the brain is made of fibres alike those of nerves and the grey matter is made of globules (i.e. cells) mixed up with fibres; he discovered in the retina a part of coming out from the brain; he described the transversal bands of fibres of the skeletal muscles; he was the first to introduce into physiology the law of "all and nothing"; he attributed the irritability to the whole animal life; he identified the pupillar reflexes to the light, the reflex of accommodation, the consensual reflex, the psycho-emotive mydriasis and at last the myosis of sleep. He made experimental searches about nerves and recognised their regeneration, he enumerated various pathological intracranial masses, he made an important anatomopathological research about hydatid cyst in the brain of the sheep affected by "capostorno" and madness, he demonstrated their parasitical nature (he said that the hydated cysts were covered inside by small animals), he come out to formulate the hypothesis that some neuropsychiatric diseases of man can depend from similar aetiology. He declared that passions may have pathological effects (psyco-somatic aetiology), but he has also drawned the attention against the danager of aprioristical generalisation of neurogenical causes in all diseases. The A.A. give to Fontana the palm of precursor

  15. Biological Indicators in Studies of Earthquake Precursors

    NASA Astrophysics Data System (ADS)

    Sidorin, A. Ya.; Deshcherevskii, A. V.

    2012-04-01

    Time series of data on variations in the electric activity (EA) of four species of weakly electric fish Gnathonemus leopoldianus and moving activity (MA) of two cat-fishes Hoplosternum thoracatum and two groups of Columbian cockroaches Blaberus craniifer were analyzed. The observations were carried out in the Garm region of Tajikistan within the frameworks of the experiments aimed at searching for earthquake precursors. An automatic recording system continuously recorded EA and DA over a period of several years. Hourly means EA and MA values were processed. Approximately 100 different parameters were calculated on the basis of six initial EA and MA time series, which characterize different variations in the EA and DA structure: amplitude of the signal and fluctuations of activity, parameters of diurnal rhythms, correlated changes in the activity of various biological indicators, and others. A detailed analysis of the statistical structure of the total array of parametric time series obtained in the experiment showed that the behavior of all animals shows a strong temporal variability. All calculated parameters are unstable and subject to frequent changes. A comparison of the data obtained with seismicity allow us to make the following conclusions: (1) The structure of variations in the studied parameters is represented by flicker noise or even a more complex process with permanent changes in its characteristics. Significant statistics are required to prove the cause-and-effect relationship of the specific features of such time series with seismicity. (2) The calculation of the reconstruction statistics in the EA and MA series structure demonstrated an increase in their frequency in the last hours or a few days before the earthquake if the hypocenter distance is comparable to the source size. Sufficiently dramatic anomalies in the behavior of catfishes and cockroaches (changes in the amplitude of activity variation, distortions of diurnal rhythms, increase in the

  16. [Felice Fontana precursor of neurosciences (author's transl)].

    PubMed

    Disertori, B; Piazza, M

    1981-01-01

    The A.A. insert the life and work of the naturalist and chemist Felice Fontana, born in Pomarolo (Trentino), in the frame of 18th century sciences, beside other great names of that century like Carolus Linnaeus, Réaumur, von Haller, Spallanzani, Morgagni, Priestley and Lavoisier. In the field of general biology, the discovery of nucleus and nucleolus and consequently the discovery of the eukaryotic cell, as we say in our days, in his, as well as the one of anabiosis. The A.A. enucleate and analyse the contributions of Fontana to the neurosciences; he has discovered the axon and the myelinic sheath half century before Remak and Purknije; he found out that the white matter of the brain is made of fibres alike those of nerves and the grey matter is made of globules (i.e. cells) mixed up with fibres; he discovered in the retina a part of coming out from the brain; he described the transversal bands of fibres of the skeletal muscles; he was the first to introduce into physiology the law of "all and nothing"; he attributed the irritability to the whole animal life; he identified the pupillar reflexes to the light, the reflex of accommodation, the consensual reflex, the psycho-emotive mydriasis and at last the myosis of sleep. He made experimental searches about nerves and recognised their regeneration, he enumerated various pathological intracranial masses, he made an important anatomopathological research about hydatid cyst in the brain of the sheep affected by "capostorno" and madness, he demonstrated their parasitical nature (he said that the hydated cysts were covered inside by small animals), he come out to formulate the hypothesis that some neuropsychiatric diseases of man can depend from similar aetiology. He declared that passions may have pathological effects (psyco-somatic aetiology), but he has also drawned the attention against the danager of aprioristical generalisation of neurogenical causes in all diseases. The A.A. give to Fontana the palm of precursor

  17. Americium recovery from reduction residues

    DOEpatents

    Conner, W.V.; Proctor, S.G.

    1973-12-25

    A process for separation and recovery of americium values from container or bomb'' reduction residues comprising dissolving the residues in a suitable acid, adjusting the hydrogen ion concentration to a desired level by adding a base, precipitating the americium as americium oxalate by adding oxalic acid, digesting the solution, separating the precipitate, and thereafter calcining the americium oxalate precipitate to form americium oxide. (Official Gazette)

  18. Role of precursor crystal structure on electrochemical performance of carbide-derived carbon electrodes

    NASA Astrophysics Data System (ADS)

    Palazzo, Benjamin; Norris, Zach; Taylor, Greg; Yu, Lei; Lofland, Samuel; Hettinger, Jeffrey

    2015-03-01

    Binary carbides with hexagonal and cubic crystal structures have been synthesized by reactive magnetron sputtering of vanadium and other transition metals in acetylene or methane gas mixed with argon. The binary carbides are converted to carbide-derived carbon (CDC) films using chlorine gas in a post-deposition process in an external vacuum reaction furnace. Residual chlorine has been removed using an annealing step in a hydrogen atmosphere. The CDC materials have been characterized by x-ray diffraction, x-ray fluorescence, and scanning electron microscopy. The performance of the CDC materials in electrochemical device applications has been measured with the hexagonal phase precursor demonstrating a significantly higher specific capacitance in comparison to that of the cubic phase. We report these results and pore-size distributions of these and similar materials.

  19. Precursor of ether phospholipids is synthesized by a flavoenzyme through covalent catalysis

    PubMed Central

    Nenci, Simone; Piano, Valentina; Rosati, Sara; Aliverti, Alessandro; Pandini, Vittorio; Fraaije, Marco W.; Heck, Albert J. R.; Edmondson, Dale E.; Mattevi, Andrea

    2012-01-01

    The precursor of the essential ether phospholipids is synthesized by a peroxisomal enzyme that uses a flavin cofactor to catalyze a reaction that does not alter the redox state of the substrates. The enzyme crystal structure reveals a V-shaped active site with a narrow constriction in front of the prosthetic group. Mutations causing inborn ether phospholipid deficiency, a very severe genetic disease, target residues that are part of the catalytic center. Biochemical analysis using substrate and flavin analogs, absorbance spectroscopy, mutagenesis, and mass spectrometry provide compelling evidence supporting an unusual mechanism of covalent catalysis. The flavin functions as a chemical trap that promotes exchange of an acyl with an alkyl group, generating the characteristic ether bond. Structural comparisons show that the covalent versus noncovalent mechanistic distinction in flavoenzyme catalysis and evolution relies on subtle factors rather than on gross modifications of the cofactor environment. PMID:23112191

  20. From peptide precursors to oxazole and thiazole-containing peptide antibiotics: microcin B17 synthase.

    PubMed

    Li, Y M; Milne, J C; Madison, L L; Kolter, R; Walsh, C T

    1996-11-15

    Esherichia coli microcin B17 is a posttranslationally modified peptide that inhibits bacterial DNA gyrase. It contains four oxazole and four thiazole rings and is representative of a broad class of pharmaceutically important natural products with five-membered heterocycles derived from peptide precursors. An in vitro assay was developed to detect heterocycle formation, and an enzyme complex, microcin B17 synthase, was purified and found to contain three proteins, McbB, McbC, and McbD, that convert 14 residues into the eight mono- and bisheterocyclic moieties in vitro that confer antibiotic activity on mature microcin B17. These enzymatic reactions alter the peptide backbone connectivity. The propeptide region of premicrocin is the major recognition determinant for binding and downstream heterocycle formation by microcin B17 synthase. A general pathway for the enzymatic biosynthesis of these heterocycles is formulated.

  1. Processing of peptide and hormone precursors at the dibasic cleavage sites.

    PubMed

    Rholam, Mohamed; Fahy, Christine

    2009-07-01

    Many functionally important cellular peptides and proteins, including hormones, neuropeptides, and growth factors, are synthesized as inactive precursor polypeptides, which require post-translational proteolytic processing to become biologically active polypeptides. This is achieved by the action of a relatively small number of proteases that belong to a family of seven subtilisin-like proprotein convertases (PCs) including furin. In view of this, this review focuses on the importance of privileged secondary structures and of given amino acid residues around basic cleavage sites in substrate recognition by these endoproteases. In addition to their participation in normal cell functions, PCs are crucial for the initiation and progress of many important diseases. Hence, these proteases constitute potential drug targets in medicine. Accordingly, this review also discusses the approaches used to shed light on the cleavage preference and the substrate specificity of the PCs, a prerequisite to select which PCs are promising drug targets in each disease. PMID:19300906

  2. Processing of peptide and hormone precursors at the dibasic cleavage sites.

    PubMed

    Rholam, Mohamed; Fahy, Christine

    2009-07-01

    Many functionally important cellular peptides and proteins, including hormones, neuropeptides, and growth factors, are synthesized as inactive precursor polypeptides, which require post-translational proteolytic processing to become biologically active polypeptides. This is achieved by the action of a relatively small number of proteases that belong to a family of seven subtilisin-like proprotein convertases (PCs) including furin. In view of this, this review focuses on the importance of privileged secondary structures and of given amino acid residues around basic cleavage sites in substrate recognition by these endoproteases. In addition to their participation in normal cell functions, PCs are crucial for the initiation and progress of many important diseases. Hence, these proteases constitute potential drug targets in medicine. Accordingly, this review also discusses the approaches used to shed light on the cleavage preference and the substrate specificity of the PCs, a prerequisite to select which PCs are promising drug targets in each disease.

  3. CD22 EXON 12 deletion as a pathogenic mechanism of human B-precursor leukemia

    PubMed Central

    Uckun, Fatih M.; Goodman, Patricia; Ma, Hong; Dibirdik, Ilker; Qazi, Sanjive

    2010-01-01

    Here, we report that primary leukemic cells from infants with newly diagnosed B-precursor leukemia express a truncated and functionally defective CD22 coreceptor protein that is unable to transmit apoptotic signals because it lacks most of the intracellular domain, including the key regulatory signal transduction elements and all of the cytoplasmic tyrosine residues. Expression of this structurally and functionally abnormal CD22 protein is associated with a very aggressive in vivo growth of patients’ primary leukemia cells causing disseminated overt leukemia in SCID mice. The abnormal CD22 coreceptor is encoded by a profoundly aberrant mRNA arising from a splicing defect that causes the deletion of exon 12 (c.2208-c.2327) (CD22ΔE12) and results in a truncating frameshift mutation. The splicing defect is associated with multiple homozygous mutations within a 132-bp segment of the intronic sequence between exons 12 and 13. These mutations cause marked changes in the predicted secondary structures of the mutant CD22 pre-mRNA sequences that affect the target motifs for the splicing factors hnRNP-L, PTB, and PCBP that are up-regulated in infant leukemia cells. Forced expression of the mutant CD22ΔE12 protein in transgenic mice perturbs B-cell development, as evidenced by B-precursor/B-cell hyperplasia, and corrupts the regulation of gene expression, causing reduced expression levels of several genes with a tumor suppressor function. We further show that CD22ΔE12-associated unique gene expression signature is a discriminating feature of newly diagnosed infant leukemia patients. These striking findings implicate CD22ΔE12 as a previously undescribed pathogenic mechanism in human B-precursor leukemia. PMID:20841423

  4. Properties of NiO thin films deposited by chemical spray pyrolysis using different precursor solutions

    NASA Astrophysics Data System (ADS)

    Cattin, L.; Reguig, B. A.; Khelil, A.; Morsli, M.; Benchouk, K.; Bernède, J. C.

    2008-07-01

    NiO thin films have been deposited by chemical spray pyrolysis using a perfume atomizer to grow the aerosol. The influence of the precursor, nickel chloride hexahydrate (NiCl 2·6H 2O), nickel nitrate hexahydrate (Ni(NO 3) 2·6H 2O), nickel hydroxide hexahydrate (Ni(OH) 2·6H 2O), nickel sulfate tetrahydrate (NiSO 4·4H 2O), on the thin films properties has been studied. In the experimental conditions used (substrate temperature 350 °C, precursor concentration 0.2-0.3 M, etc.), pure NiO thin films crystallized in the cubic phase can be achieved only with NiCl 2 and Ni(NO 3) 2 precursors. These films have been post-annealed at 425 °C for 3 h either in room atmosphere or under vacuum. If all the films are p-type, it is shown that the NiO films conductivity and optical transmittance depend on annealing process. The properties of the NiO thin films annealed under room atmosphere are not significantly modified, which is attributed to the fact that the temperature and the environment of this annealing is not very different from the experimental conditions during spray deposition. The annealing under vacuum is more efficient. This annealing being proceeded in a vacuum no better than 10 -2 Pa, it is supposed that the modifications of the NiO thin film properties, mainly the conductivity and optical transmission, are related to some interaction between residual oxygen and the films.

  5. Liquid precursor for deposition of copper selenide and method of preparing the same

    SciTech Connect

    Curtis, Calvin J.; Miedaner, Alexander; Franciscus Antonius Maria Van Hest, Marinus; Ginley, David S.; Hersh, Peter A.; Eldada, Louay; Stanbery, Billy J.

    2015-09-08

    Liquid precursors containing copper and selenium suitable for deposition on a substrate to form thin films suitable for semiconductor applications are disclosed. Methods of preparing such liquid precursors and methods of depositing a precursor on a substrate are also disclosed.

  6. Precursor composites for oxygen dispersion hardened silver sheathed superconductor composites

    DOEpatents

    Podtburg, Eric R.

    1999-01-01

    An oxide superconductor composite having improved texture and durability. The oxide superconductor composite includes an oxide superconductor phase substantially surrounded with/by a noble metal matrix, the noble metal matrix comprising a metal oxide in an amount effective to form metal oxide domains that increase hardness of the composite. The composite is characterized by a degree of texture at least 10% greater than a comparable oxide superconductor composite lacking metal oxide domains. An oxide superconducting composite may be prepared by oxidizing the precursor composite under conditions effective to form solute metal oxide domains within the silver matrix and to form a precursor oxide in the precursor alloy phase; subjecting the oxidized composite to a softening anneal under conditions effective to relieve stress within the noble metal phase; and converting the oxide precursor into an oxide superconductor.

  7. Precursor composites for oxygen dispersion hardened silver sheathed superconductor composites

    DOEpatents

    Podtburg, E.R.

    1999-06-22

    An oxide superconductor composite having improved texture and durability is disclosed. The oxide superconductor composite includes an oxide superconductor phase substantially surrounded with/by a noble metal matrix, the noble metal matrix comprising a metal oxide in an amount effective to form metal oxide domains that increase hardness of the composite. The composite is characterized by a degree of texture at least 10% greater than a comparable oxide superconductor composite lacking metal oxide domains. An oxide superconducting composite may be prepared by oxidizing the precursor composite under conditions effective to form solute metal oxide domains within the silver matrix and to form a precursor oxide in the precursor alloy phase; subjecting the oxidized composite to a softening anneal under conditions effective to relieve stress within the noble metal phase; and converting the oxide precursor into an oxide superconductor. 1 fig.

  8. Quarternary Amines as Nitrosamine Precursors: A Role for Consumer Products?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrosamine formation is associated with wastewater-impacted water supplies, but the specific precursors within municipal wastewater effluents have not been identified. Quaternary amines are significant constituents of consumer products, including shampoos, detergents and fabric softeners. Experimen...

  9. DISSOLUTION OF NEPTUNIUM OXIDE RESIDUES

    SciTech Connect

    Kyser, E

    2009-01-12

    This report describes the development of a dissolution flowsheet for neptunium (Np) oxide (NpO{sub 2}) residues (i.e., various NpO{sub 2} sources, HB-Line glovebox sweepings, and Savannah River National Laboratory (SRNL) thermogravimetric analysis samples). Samples of each type of materials proposed for processing were dissolved in a closed laboratory apparatus and the rate and total quantity of off-gas were measured. Samples of the off-gas were also analyzed. The quantity and type of solids remaining (when visible) were determined after post-dissolution filtration of the solution. Recommended conditions for dissolution of the NpO{sub 2} residues are: Solution Matrix and Loading: {approx}50 g Np/L (750 g Np in 15 L of dissolver solution), using 8 M nitric acid (HNO{sub 3}), 0.025 M potassium fluoride (KF) at greater than 100 C for at least 3 hours. Off-gas: Analysis of the off-gas indicated nitric oxide (NO), nitrogen dioxide (NO{sub 2}) and nitrous oxide (N{sub 2}O) as the only identified components. No hydrogen (H{sub 2}) was detected. The molar ratio of off-gas produced per mole of Np dissolved ranged from 0.25 to 0.4 moles of gas per mole of Np dissolved. A peak off-gas rate of {approx}0.1 scfm/kg bulk oxide was observed. Residual Solids: Pure NpO{sub 2} dissolved with little or no residue with the proposed flowsheet but the NpCo and both sweepings samples left visible solid residue after dissolution. For the NpCo and Part II Sweepings samples the residue amounted to {approx}1% of the initial material, but for the Part I Sweepings sample, the residue amounted to {approx}8 % of the initial material. These residues contained primarily aluminum (Al) and silicon (Si) compounds that did not completely dissolve under the flowsheet conditions. The residues from both sweepings samples contained minor amounts of plutonium (Pu) particles. Overall, the undissolved Np and Pu particles in the residues were a very small fraction of the total solids.

  10. Structure of Alzheimer’s disease amyloid precursor protein copper-binding domain at atomic resolution

    SciTech Connect

    Kong, Geoffrey Kwai-Wai; Adams, Julian J.; Cappai, Roberto; Parker, Michael W.

    2007-10-01

    An atomic resolution structure of the copper-binding domain of the Alzheimer’s disease amyloid precursor protein is presented. Amyloid precursor protein (APP) plays a central role in the pathogenesis of Alzheimer’s disease, as its cleavage generates the Aβ peptide that is toxic to cells. APP is able to bind Cu{sup 2+} and reduce it to Cu{sup +} through its copper-binding domain (CuBD). The interaction between Cu{sup 2+} and APP leads to a decrease in Aβ production and to alleviation of the symptoms of the disease in mouse models. Structural studies of CuBD have been undertaken in order to better understand the mechanism behind the process. Here, the crystal structure of CuBD in the metal-free form determined to ultrahigh resolution (0.85 Å) is reported. The structure shows that the copper-binding residues of CuBD are rather rigid but that Met170, which is thought to be the electron source for Cu{sup 2+} reduction, adopts two different side-chain conformations. These observations shed light on the copper-binding and redox mechanisms of CuBD. The structure of CuBD at atomic resolution provides an accurate framework for structure-based design of molecules that will deplete Aβ production.

  11. SorLA Complement-type Repeat Domains Protect the Amyloid Precursor Protein against Processing*

    PubMed Central

    Mehmedbasic, Arnela; Christensen, Sofie K.; Nilsson, Jonas; Rüetschi, Ulla; Gustafsen, Camilla; Poulsen, Annemarie Svane Aavild; Rasmussen, Rikke W.; Fjorback, Anja N.; Larson, Göran; Andersen, Olav M.

    2015-01-01

    SorLA is a neuronal sorting receptor that is genetically associated with Alzheimer disease. SorLA interacts directly with the amyloid precursor protein (APP) and affects the processing of the precursor, leading to a decreased generation of the amyloid-β peptide. The SorLA complement-type repeat (CR) domains associate in vitro with APP, but the precise molecular determinants of SorLA·APP complex formation and the mechanisms responsible for the effect of binding on APP processing have not yet been elucidated. Here, we have generated protein expression constructs for SorLA devoid of the 11 CR-domains and for two SorLA mutants harboring substitutions of the fingerprint residues in the central CR-domains. We generated SH-SY5Y cell lines that stably express these SorLA variants to study the binding and processing of APP using co-immunoprecipitation and Western blotting/ELISAs, respectively. We found that the SorLA CR-cluster is essential for interaction with APP and that deletion of the CR-cluster abolishes the protection against APP processing. Mutation of identified fingerprint residues in the SorLA CR-domains leads to changes in the O-linked glycosylation of APP when expressed in SH-SY5Y cells. Our results provide novel information on the mechanisms behind the influence of SorLA activity on APP metabolism by controlling post-translational glycosylation in the Golgi, suggesting new strategies against amyloidogenesis in Alzheimer disease. PMID:25525276

  12. Shape-programmed nanofabrication: understanding the reactivity of dichalcogenide precursors.

    PubMed

    Guo, Yijun; Alvarado, Samuel R; Barclay, Joshua D; Vela, Javier

    2013-04-23

    Dialkyl and diaryl dichalcogenides are highly versatile and modular precursors for the synthesis of colloidal chalcogenide nanocrystals. We have used a series of commercially available dichalcogenide precursors to unveil the molecular basis for the outcome of nanocrystal preparations, more specifically, how precursor molecular structure and reactivity affect the final shape and size of II-VI semiconductor nanocrystals. Dichalcogenide precursors used were diallyl, dibenzyl, di-tert-butyl, diisopropyl, diethyl, dimethyl, and diphenyl disulfides and diethyl, dimethyl, and diphenyl diselenides. We find that the presence of two distinctively reactive C-E and E-E bonds makes the chemistry of these precursors much richer and interesting than that of other conventional precursors such as the more common phosphine chalcogenides. Computational studies (DFT) reveal that the dissociation energy of carbon-chalcogen (C-E) bonds in dichalcogenide precursors (R-E-E-R, E=S or Se) increases in the order (R): diallylprecursor reactivity, leading to progressively slower nucleation and higher selectivity for anisotropic growth, all the way from dots to pods to tetrapods. Under identical experimental conditions, we obtain CdS and CdSe nanocrystals with spherical, elongated, or tetrapodal morphology by simply varying the identity and reactivity of the dichalcogenide precursor. Interestingly, we find that precursors with strong C-E and weak E-E bond dissociation energies such as Ph-S-S-Ph serve as a ready source of thiol radicals that appear to stabilize small CdE nuclei, facilitating anisotropic growth. These CdS and CdSe nanocrystals have been

  13. Kinetic mechanism and characterization of human beta-galactosidase precursor secreted by permanently transfected Chinese hamster ovary cells.

    PubMed

    Zhang, S; McCarter, J D; Okamura-Oho, Y; Yaghi, F; Hinek, A; Withers, S G; Callahan, J W

    1994-11-15

    Chinese hamster ovary cell clones permanently transfected with the cDNA for human lysosomal beta-galactosidase secrete the enzyme precursor into the cell medium, from which it is purified to apparent homogeneity in a single step by affinity chromatography. The purified precursor is fully active, displays the same pH optimum and Km values as the mature placental enzyme, and has an intact C-terminus. The intact enzyme when chromatographed on a Sephacryl S-200 molecular-sieve column elutes as a 105,500 Da monomer, whereas on SDS/PAGE gels the polypeptide migrates as an 88 kDa polypeptide. A time course of digestion with glycopeptide-N-glycanase shows the gradual conversion of the precursor from an 88 to a 72 kDa protein, suggesting the presence of five N-linked oligosaccharides in the protein. The precursor is readily taken up in a mannose-6-phosphate-dependent manner into beta-galactosidase-deficient, GM1-gangliosidosis fibroblasts, and the enzyme activity is returned to normal levels. We show that the stereochemical course of enzymic hydrolysis involves the retention of the beta-configuration at the anomeric centre, suggesting a double-displacement mechanism. Furthermore, the enzyme is rapidly and irreversibly inactivated in the presence of the mechanism-based inactivator 2,4-dinitrophenyl-2-deoxy-2-fluoro-beta-D-galactopyranoside, which implicates a covalent intermediate. The enzyme is also inactivated by 1-ethyl-3(3-dimethylamino-propyl)carbodi-imide and by phenylglyoxal, which implicates carboxylate and arginine residues respectively in the active site. We conclude that the beta-galactosidase precursor is functionally identical to the mature lysosomal form of the enzyme and serves as an excellent enzyme source for investigation of structure-function relationships in the protein.

  14. Experimental observation of optical precursors in optically pumped crystals

    NASA Astrophysics Data System (ADS)

    Zhou, Zong-Quan; Li, Chuan-Feng; Guo, Guang-Can

    2013-04-01

    We experimentally observed optical precursors in optically pumped crystals using polarization-based interference. By switching the user-programmable medium among the fast light, slow light, and no-dispersion regimes, we observed an unchanged polarization state for the wave fronts. The robust polarization-encoded information carried by wave fronts suggests that precursors are the preferred carriers for both quantum and classical information in communication networks.

  15. Continuous-flow synthesis of trimethylsilylphenyl perfluorosulfonate benzyne precursors.

    PubMed

    Michel, Boris; Greaney, Michael F

    2014-05-16

    2-(Trimethylsilyl)phenyl perfluorosulfonated aryne precursors may now be accessed using flow chemistry, enabling the fast preparation of pure compounds with no requirement for low temperature lithiation or column chromatography. The process has been adapted to novel nonaflate precursors, utilizing the cheaper and more user-friendly nonaflyl fluoride reagent. The resultant nonaflates are shown to successfully participate in a range of aryne reaction classes.

  16. Improved Single-Source Precursors for Solar-Cell Absorbers

    NASA Technical Reports Server (NTRS)

    Banger, Kulbinder K.; Harris, Jerry; Hepp, Aloysius

    2007-01-01

    Improved single-source precursor compounds have been invented for use in spray chemical vapor deposition (spray CVD) of chalcopyrite semiconductor absorber layers of thin-film cells. A "single-source precursor compound" is a single molecular compound that contains all the required elements, which when used under the spray CVD conditions, thermally decomposes to form CuIn(x)Ga(1-x)S(y)Se(2-y).

  17. Precursors for the polymer-assisted deposition of films

    DOEpatents

    McCleskey, Thomas M.; Burrell, Anthony K.; Jia, Quanxi; Lin, Yuan

    2013-09-10

    A polymer assisted deposition process for deposition of metal oxide films is presented. The process includes solutions of one or more metal precursor and soluble polymers having binding properties for the one or more metal precursor. After a coating operation, the resultant coating is heated at high temperatures to yield metal oxide films. Such films can be epitaxial in structure and can be of optical quality. The process can be organic solvent-free.

  18. Recombinant expression of the precursor of the hemorrhagic metalloproteinase HF3 and its non-catalytic domains using a cell-free synthesis system.

    PubMed

    Menezes, Milene C; Imbert, Lionel; Kitano, Eduardo S; Vernet, Thierry; Serrano, Solange M T

    2016-09-01

    Snake venom metalloproteinases (SVMPs) participate in snakebite pathology such as hemorrhage, inflammation, and necrosis. They are synthesized as latent multi-domain precursors whose processing generates either catalytically active enzymes or free non-enzymatic domains. Recombinant expression of the precursor of P-III class SVMPs has failed due to the instability of the multi-domain polypeptide structure. Conversely, functional recombinant non-catalytic domains were obtained by prokaryotic expression systems. Here, we show for the first time the recombinant expression of the precursor of HF3, a highly hemorrhagic SVMP from Bothrops jararaca, and its non-catalytic domains, using an E. coli-based cell-free synthesis system. The precursor of HF3, composed of pro-, metalloproteinase-, disintegrin-like-, and cysteine-rich domains, and containing 38 Cys residues, was successfully expressed and purified. A protein composed of the disintegrin-like and cysteine-rich domains (DC protein) and the cysteine-rich domain alone (C protein) were expressed in vitro individually and purified. Both proteins were shown to be functional in assays monitoring the interaction with matrix proteins and in modulating the cleavage of fibrinogen by HF3. These data indicate that recombinant expression using prokaryotic-based cell-free synthesis emerges as an attractive alternative for the study of the structure and function of multi-domain proteins with a high content of Cys residues. PMID:27209197

  19. Novel Neo-Pentoxide Precursors for MOCVD Thin Films of TiO(2) and ZrO(2).[1

    SciTech Connect

    Boyle, Timothy J.; Francisco, Laila P.; Gallegos, Jesus J.; Rodriguez, Mark A.; Ward, Timothy L.

    1999-07-14

    Two novel Group IV precursors, titanium (IV) neo-pentoxide, [Ti({mu}-ONep)(ONep){sub 3}]{sub 2} (l), and zirconium (IV) neo-pentoxide, [Zr({mu}-ONep)(ONep){sub 3}]{sub 2} (2), were reported to possess relatively high volatility at low temperatures. These compounds were therefore investigated as MOCVD precursors using a lamp-heated cold-wall CVD reactor and direct sublimation without carrier gas. The ONep derivatives proved to be competitive precursors for the production of thin films of the appropriate MO{sub 2} (M = Ti or Zr) materials in comparison to other metallo-organic precursors. Compound 1 was found to sublime at 120 C with a deposition rate of {approximately}0.350 {mu}m/min onto a substrate at 330 C forming the anatase phase with < 1% residual C found in the final film. Compound 2 was found to sublime at 160 C and deposited as crystalline material at 300 C with < 1% residual C found in the final film. A comparison to standard alkoxide and {beta}-diketonates is presented where appropriate.

  20. Residual stresses in welded plates

    NASA Technical Reports Server (NTRS)

    Bernstein, Edward L.

    1994-01-01

    The purpose of this project was to develop a simple model which could be used to study residual stress. The mechanism that results in residual stresses in the welding process starts with the deposition of molten weld metal which heats the immediately adjacent material. After solidification of weld material, normal thermal shrinkage is resisted by the adjacent, cooler material. When the thermal strain exceeds the elastic strain corresponding to the yield point stress, the stress level is limited by this value, which decreases with increasing temperature. Cooling then causes elastic unloading which is restrained by the adjoining material. Permanent plastic strain occurs, and tension is caused in the region immediately adjacent to the weld material. Compression arises in the metal farther from the weld in order to maintain overall static equilibrium. Subsequent repair welds may add to the level of residual stresses. The level of residual stress is related to the onset of fracture during welding. Thus, it is of great importance to be able to predict the level of residual stresses remaining after a weld procedure, and to determine the factors, such as weld speed, temperature, direction, and number of passes, which may affect the magnitude of remaining residual stress. It was hoped to use traditional analytical modeling techniques so that it would be easier to comprehend the effect of these variables on the resulting stress. This approach was chosen in place of finite element methods so as to facilitate the understanding of the physical processes. The accuracy of the results was checked with some existing experimental studies giving residual stress levels found from x-ray diffraction measurements.

  1. Technique for the identification of dominant delayed neutron precursors.

    SciTech Connect

    Loaiza, D. J.; Haskin, E.

    2001-01-01

    A technique for the identification of delayed neutron precursors has been developed based on the product of cumulative yield and probability of neutron emission. The motivation behind this work is to fix the decay constants of delayed neutrons to those of the dominant delayed neutron precursors. The desirability of identifying a single set of decay constants that would apply to all fissionable isotopes and be independent of the neutron energy spectrum has been addressed by several authors. The main advantages of a fixed-decay constant representation are simplifying the analysis of epithemal and fast reactors with multiple fissioning isotopes, and improving the fit to experimental data while preserving the inferred positive reactivity scale associated with the original six-group representation. It is well known that 27 1 delayed neutron precursors exist, but only a select number of those precursors contribute significantly to the decay of delayed neutron. Using data compiled by England and Rider, which lists fission yield and probability of neutron emission values for the 27 1 known delayed neutron precursors in 32 fissioning systems, thirteen precursors were identified that are consistently dominant for alI fissioning systems.

  2. Risk Assessment of Infrastructure System of Systems with Precursor Analysis.

    PubMed

    Guo, Zhenyu; Haimes, Yacov Y

    2016-08-01

    Physical infrastructure systems are commonly composed of interconnected and interdependent subsystems, which in their essence constitute system of systems (S-o-S). System owners and policy researchers need tools to foresee potential emergent forced changes and to understand their impact so that effective risk management strategies can be developed. We develop a systemic framework for precursor analysis to support the design of an effective and efficient precursor monitoring and decision support system with the ability to (i) identify and prioritize indicators of evolving risks of system failure; and (ii) evaluate uncertainties in precursor analysis to support informed and rational decision making. This integrated precursor analysis framework is comprised of three processes: precursor identification, prioritization, and evaluation. We use an example of a highway bridge S-o-S to demonstrate the theories and methodologies of the framework. Bridge maintenance processes involve many interconnected and interdependent functional subsystems and decision-making entities and bridge failure can have broad social and economic consequences. The precursor analysis framework, which constitutes an essential part of risk analysis, examines the impact of various bridge inspection and maintenance scenarios. It enables policy researchers and analysts who are seeking a risk perspective on bridge infrastructure in a policy setting to develop more risk informed policies and create guidelines to efficiently allocate limited risk management resources and mitigate severe consequences resulting from bridge failures. PMID:27575259

  3. Risk Assessment of Infrastructure System of Systems with Precursor Analysis.

    PubMed

    Guo, Zhenyu; Haimes, Yacov Y

    2016-08-01

    Physical infrastructure systems are commonly composed of interconnected and interdependent subsystems, which in their essence constitute system of systems (S-o-S). System owners and policy researchers need tools to foresee potential emergent forced changes and to understand their impact so that effective risk management strategies can be developed. We develop a systemic framework for precursor analysis to support the design of an effective and efficient precursor monitoring and decision support system with the ability to (i) identify and prioritize indicators of evolving risks of system failure; and (ii) evaluate uncertainties in precursor analysis to support informed and rational decision making. This integrated precursor analysis framework is comprised of three processes: precursor identification, prioritization, and evaluation. We use an example of a highway bridge S-o-S to demonstrate the theories and methodologies of the framework. Bridge maintenance processes involve many interconnected and interdependent functional subsystems and decision-making entities and bridge failure can have broad social and economic consequences. The precursor analysis framework, which constitutes an essential part of risk analysis, examines the impact of various bridge inspection and maintenance scenarios. It enables policy researchers and analysts who are seeking a risk perspective on bridge infrastructure in a policy setting to develop more risk informed policies and create guidelines to efficiently allocate limited risk management resources and mitigate severe consequences resulting from bridge failures.

  4. Simple asymptotic forms for Sommerfeld and Brillouin precursors

    NASA Astrophysics Data System (ADS)

    Macke, Bruno; Ségard, Bernard

    2012-07-01

    This article mainly deals with the propagation of step-modulated light pulses in a dense Lorentz medium at distances such that the medium is opaque in a broad spectral region including the carrier frequency. The transmitted field is then reduced to the celebrated precursors of Sommerfeld and Brillouin, far apart from each other. We obtain simple analytical expressions of the first (Sommerfeld) precursor, whose shape only depends on the order of the initial discontinuity of the incident field and whose amplitude rapidly decreases with this order (rise-time effects). We show that, in a strictly asymptotic limit, the second (Brillouin) precursor is entirely determined by the frequency dependence of the medium attenuation and has a Gaussian or Gaussian-derivative shape. We point out that this result applies to the precursor directly observed in a Debye medium at decimetric wavelengths. When attenuation and group-delay dispersion both contribute to its formation, we establish a more general expression of the Brillouin precursor, containing the previous one (dominant-attenuation limit) and that obtained by Brillouin (dominant-dispersion limit) as particular cases. We finally study the propagation of square or Gaussian pulses, and we determine the pulse parameters optimizing the Brillouin precursor. Obtained by standard Laplace-Fourier procedures, our results are explicit and contrast in their simplicity those derived by the uniform saddle-point methods, from which it is difficult to retrieve our asymptotic forms.

  5. Elements of the tsunami precursors' detection physics

    NASA Astrophysics Data System (ADS)

    Novik, Oleg; Ruzhin, Yuri; Ershov, Sergey; Volgin, Max; Smirnov, Fedor

    ionosphere from the buoy, balloon and satellite complexes. The balloon and buoy complexes will transmit data to a shore station over satellite link. The frequency ranges and sensitivity thresholds of all of the sensors of the LOAMS will be adapted to the characteristics of expected seismic signals according to the numerical research above. Computational methods and statistical analysis (e.g. seismic changes of coherence of spatially distributed sensors of different nature) of the recorded multidimensional time series will be used for prognostic interpretation. The multilevel recordings will provide a stable noise (e.g. ionosphere Pc pulsations, hard sea, industry) and seismic event detection. An intensive heat flow typical for tectonically active lithosphere zones may be considered as an energy source for advanced modifications of the LOAMS. The latter may be used as a warning system for continental and marine technologies, e.g. a sea bottom geothermal energy production. Indeed, seismic distraction of the nuclear power station Fukushima I demonstrates that similar technology hardly is able to solve the energy problems in seismically active regions. On the other hand, the LOAMS may be considered as a scientific observatory for development of the seaquake/tsunami precursor physics, i.e. seismo-hydro-electromagnetics.

  6. High critical current density Bi2Sr2CaCu2O x /Ag wire containing oxide precursor synthesized from nano-oxides

    NASA Astrophysics Data System (ADS)

    Zhang, Yun; Johnson, Stephen; Naderi, Golsa; Chaubal, Manasi; Hunt, Andrew; Schwartz, Justin

    2016-09-01

    Bi2Sr2CaCu2O x (Bi2212)/Ag-alloy wires are manufactured via the oxide-powder-in-tube route by filling Ag/Ag-alloy tubes with Bi2212 oxide precursor, deforming into wire, restacking and heat treating using partial-melt processing (PMP). Recent studies propose several requirements on precursor properties, including stoichiometry, chemical homogeneity, carbon content and phase purity. Here, nanosize oxides produced by nGimat’s proprietary NanoSpray CombustionTM process are used as starting materials to synthesize Bi2212 oxide precursors via solid-state calcination. Oxide powders for wire fill (precursor powder) with precisely controlled stoichiometry and chemical homogeneity containing over 99 vol% of single Bi2212-phase are synthesized. Alkaline-earth cuprate are found to be the only impurity phase in the precursor powders. Phase transformation, carbon release and grain growth during calcination are studied through a series of quench studies. Effects of particle size, surface area, stoichiometry, chemical homogeneity and microstructures of the starting materials on Bi2212 formation and wire transport properties are discussed. Small particle size, high surface area and short diffusion length of the starting materials result in a rapid and homogeneous phase transformation to Bi2212, along with an early and rapid carbon release. The residual carbon in the precursor powder is between 50 and 90 ppm. The strong dependence of transport J c on precursor stoichiometry indicates that compositional variations within precursor powders should be less than 1.5 mol%. Two Bi-rich and Ca-deficient stoichiometries give higher wire transport critical current density, with the highest being 2520 A mm-2 (4.2 K, 5 T) after 1 bar PMP and 4560 A mm-2 (4.2 K, 5 T) after 100 bar overpressure (OP) processing. The low residual carbon content results in smaller and fewer voids within an OP-processed wire filament. Bi-rich and Ca-deficient stoichiometries and small compositional variations

  7. High critical current density Bi2Sr2CaCu2O x /Ag wire containing oxide precursor synthesized from nano-oxides

    NASA Astrophysics Data System (ADS)

    Zhang, Yun; Johnson, Stephen; Naderi, Golsa; Chaubal, Manasi; Hunt, Andrew; Schwartz, Justin

    2016-09-01

    Bi2Sr2CaCu2O x (Bi2212)/Ag-alloy wires are manufactured via the oxide-powder-in-tube route by filling Ag/Ag-alloy tubes with Bi2212 oxide precursor, deforming into wire, restacking and heat treating using partial-melt processing (PMP). Recent studies propose several requirements on precursor properties, including stoichiometry, chemical homogeneity, carbon content and phase purity. Here, nanosize oxides produced by nGimat’s proprietary NanoSpray CombustionTM process are used as starting materials to synthesize Bi2212 oxide precursors via solid-state calcination. Oxide powders for wire fill (precursor powder) with precisely controlled stoichiometry and chemical homogeneity containing over 99 vol% of single Bi2212-phase are synthesized. Alkaline-earth cuprate are found to be the only impurity phase in the precursor powders. Phase transformation, carbon release and grain growth during calcination are studied through a series of quench studies. Effects of particle size, surface area, stoichiometry, chemical homogeneity and microstructures of the starting materials on Bi2212 formation and wire transport properties are discussed. Small particle size, high surface area and short diffusion length of the starting materials result in a rapid and homogeneous phase transformation to Bi2212, along with an early and rapid carbon release. The residual carbon in the precursor powder is between 50 and 90 ppm. The strong dependence of transport J c on precursor stoichiometry indicates that compositional variations within precursor powders should be less than 1.5 mol%. Two Bi-rich and Ca-deficient stoichiometries give higher wire transport critical current density, with the highest being 2520 A mm‑2 (4.2 K, 5 T) after 1 bar PMP and 4560 A mm‑2 (4.2 K, 5 T) after 100 bar overpressure (OP) processing. The low residual carbon content results in smaller and fewer voids within an OP-processed wire filament. Bi-rich and Ca-deficient stoichiometries and small compositional variations

  8. Bradykinins and their precursor cDNAs from the skin of the fire-bellied toad (Bombina orientalis).

    PubMed

    Chen, Tianbao; Orr, David F; Bjourson, Anthony J; McClean, Stephen; O'Rourke, Martin; Hirst, David G; Rao, Pingfan; Shaw, Chris

    2002-09-01

    Bradykinin and (Thr(6))-bradykinin have been identified in the defensive skin secretion of the fire-bellied toad, Bombina orientalis. The homologous cDNAs for both peptides were cloned from a skin library using a 3'- and 5'-RACE strategy. Kininogen-1 (BOK-1) contained an open-reading frame of 167 amino acid residues encoding four repeats of bradykinin, and kininogen-2 (BOK-2) contained an open-reading frame of 161 amino acid residues encoding two repeats of (Thr(6))-bradykinin. Alignment of both precursor nucleotide and amino acid sequences revealed a high degree of structural similarity. These amphibian skin kininogens/preprobradykinins are not biologically analogous to mammalian kininogens.

  9. Detection of the single-chain precursor in the production and purification process of recombinant human insulin.

    PubMed

    Leng, Chunsheng; Li, Qingwei; Wu, Fenfang; Chen, Liyong; Su, Peng

    2013-08-01

    High quality recombinant insulin requires being free of single-chain precursor (proinsulin), a task that depends on the selectivity and sensitivity of the monitoring process for detecting proinsulin. In this study we developed an enzyme-linked immunosorbent assay (ELISA) system that was specifically tailored to detect recombinant proinsulin. The proinsulin consists of six components: an initiating methionine, 48 amino acids from human growth hormones (HGH, used as the protection peptide), first connecting Arg-residue, B-chain of insulin, and second connecting Arg-peptide and A-chain of insulin. This form of proinsulin is more stable and can be efficiently expressed by E. coli than insulin. Herein, we evaluated the specificity, precision, recovery, sensitivity, and detection range of the proinsulin ELISA kit. The results showed that the ELISA kit is a very useful tool for monitoring the proinsulin yield in early stages of insulin production as well as the residual proinsulin in the final product, insulin.

  10. Facilitation of stress-induced phosphorylation of beta-amyloid precursor protein family members by X11-like/Mint2 protein.

    PubMed

    Taru, Hidenori; Suzuki, Toshiharu

    2004-05-14

    Beta-amyloid precursor protein (APP) is the precursor of beta-amyloid (Abeta), which is implicated in Alzheimer's disease pathogenesis. APP complements amyloid precursor-like protein 2 (APLP2), and together they play essential physiological roles. Phosphorylation at the Thr(668) residue of APP (with respect to the numbering conversion for the APP 695 isoform) and the Thr(736) residue of APLP2 (with respect to the numbering conversion for the APLP2 763 isoform) in their cytoplasmic domains acts as a molecular switch for their protein-protein interaction and is implicated in neural function(s) and/or Alzheimer's disease pathogenesis. Here we demonstrate that both APP and APLP2 can be phosphorylated by JNK at the Thr(668) and Thr(736) residues, respectively, in response to cellular stress. X11-like (X11L, also referred to as X11beta and Mint2), which is a member of the mammalian LIN-10 protein family and a possible regulator of Abeta production, elevated APP and APLP2 phosphorylation probably by facilitating JNK-mediated phosphorylation, whereas other members of the family, X11 and X11L2, did not. These observations revealed an involvement of X11L in the phosphorylation of APP family proteins in cellular stress and suggest that X11L protein may be important in the physiology of APP family proteins as well as in the regulation of Abeta production.

  11. Predicting Solar Cycle 24 Using a Geomagnetic Precursor Pair

    NASA Technical Reports Server (NTRS)

    Pesnell, W. Dean

    2014-01-01

    We describe using Ap and F(10.7) as a geomagnetic-precursor pair to predict the amplitude of Solar Cycle 24. The precursor is created by using F(10.7) to remove the direct solar-activity component of Ap. Four peaks are seen in the precursor function during the decline of Solar Cycle 23. A recurrence index that is generated by a local correlation of Ap is then used to determine which peak is the correct precursor. The earliest peak is the most prominent but coincides with high levels of non-recurrent solar activity associated with the intense solar activity of October and November 2003. The second and third peaks coincide with some recurrent activity on the Sun and show that a weak cycle precursor closely following a period of strong solar activity may be difficult to resolve. A fourth peak, which appears in early 2008 and has recurrent activity similar to precursors of earlier solar cycles, appears to be the "true" precursor peak for Solar Cycle 24 and predicts the smallest amplitude for Solar Cycle 24. To determine the timing of peak activity it is noted that the average time between the precursor peak and the following maximum is approximately equal to 6.4 years. Hence, Solar Cycle 24 would peak during 2014. Several effects contribute to the smaller prediction when compared with other geomagnetic-precursor predictions. During Solar Cycle 23 the correlation between sunspot number and F(10.7) shows that F(10.7) is higher than the equivalent sunspot number over most of the cycle, implying that the sunspot number underestimates the solar-activity component described by F(10.7). During 2003 the correlation between aa and Ap shows that aa is 10 % higher than the value predicted from Ap, leading to an overestimate of the aa precursor for that year. However, the most important difference is the lack of recurrent activity in the first three peaks and the presence of significant recurrent activity in the fourth. While the prediction is for an amplitude of Solar Cycle 24 of

  12. Dry fermentation of agricultural residues

    NASA Astrophysics Data System (ADS)

    Jewell, W. J.; Chandler, J. A.; Dellorto, S.; Fanfoni, K. J.; Fast, S.; Jackson, D.; Kabrick, R. M.

    1981-09-01

    A dry fermentation process is discussed which converts agricultural residues to methane, using the residues in their as produced state. The process appears to simplify and enhance the possibilities for using crop residues as an energy source. The major process variables investigated include temperature, the amount and type of inoculum, buffer requirements, compaction, and pretreatment to control the initial available organic components that create pH problems. A pilot-scale reactor operation on corn stover at a temperature of 550 C, with 25 percent initial total solids, a seed-to-feed ratio of 2.5 percent, and a buffer-to-feed ratio of 8 percent achieved 33 percent total volatile solids destruction in 60 days. Volumetric biogas yields from this unit were greater than 1 vol/vol day for 12 days, and greater than 0.5 vol/vol day for 32 days, at a substrate density of 169 kg/m (3).

  13. Characterization of uniformly and atom-specifically 13C-labeled heparin and heparan sulfate polysaccharide precursors using 13C NMR spectroscopy and ESI mass spectrometry

    PubMed Central

    Nguyen, Thao K. N.; Tran, Vy M.; Victor, Xylophone V.; Skalicky, Jack J.; Kuberan, Balagurunathan

    2010-01-01

    The biological actions of heparin and heparan sulfate, two structurally related glycosaminoglycans, depend on the organization of the complex heparanome. Due to the structural complexity of the heparanome, the sequence of variably sulfonated uronic acid and glucosamine residues is usually characterized by the analysis of smaller oligosaccharide and disaccharide fragments. Even characterization of smaller heparin/heparan sulfate oligosaccharide or disaccharide fragments using simple 1D 1H NMR spectroscopy is often complicated by the extensive signal overlap. 13C NMR signals, on the other hand, overlap less and therefore, 13C NMR spectroscopy can greatly facilitate the structural elucidation of the complex heparanome and provide finer insights into the structural basis for biological functions. This is the first report of the preparation of anomeric carbon-specific 13C-labeled heparin/heparan sulfate precursors from the Escherichia coli K5 strain. Uniformly 13C- and 15N-labeled precursors were also produced and characterized by 13C NMR spectroscopy. Mass spectrometric analysis of enzymatically fragmented disaccharides revealed that anomeric carbon-specific labeling efforts resulted in a minor loss/scrambling of 13C in the precursor backbone, whereas uniform labeling efforts resulted in greater than 95% 13C isotope enrichment in the precursor backbone. These labeled precursors provided high-resolution NMR signals with great sensitivity and set the stage for studying the heparanome–proteome interactions. PMID:20832774

  14. Residual contact restraints in cryogenics

    NASA Astrophysics Data System (ADS)

    Cretegny, J. F.; Demonicault, J. M.

    The use of residual stress measurements to evaluate the state of cryogenic turbomachines, whose surfaces are worn by the working conductions in dry contact, is addressed. Their contribution to the understanding of the reasons of possible ruptures is considered. It is stated that residual stress measurements should be used as a complementary tool rather than as input data for models. It is shown, thanks to two examples concerning the ball bearings and splines of the liquid hydrogen turbopump of the Vulcain engine, what can be expected from such techniques. Total exploitation of the results has still to be done, but preliminary results are quite encouraging.

  15. Collection of sugarcane crop residue for energy

    SciTech Connect

    Eiland, B.R.; Clayton, J.E.

    1982-12-01

    Crop residue left after sugarcane harvesting was recovered using a forage harvester and a large round baler. The quantity, bulk density and moisture content of the crop residue was determined in four fields. Crop residue from 7 ha was burned in boilers at a sugar mill. Samples of this residue were tested by a laboratory and compared to sugarcane bagasse.

  16. Altered neutrophil immunophenotypes in childhood B-cell precursor acute lymphoblastic leukemia

    PubMed Central

    Oliveira, Elen; Bacelar, Thiago S.; Ciudad, Juana; Ribeiro, Maria Cecília M.; Garcia, Daniela R.N.; Sedek, Lukasz; Maia, Simone F.; Aranha, Daniel B.; Machado, Indyara C.; Ikeda, Arissa; Baglioli, Bianca F.; Lopez-Duarte, Nathalia; Teixeira, Lisandra A. C.; Szczepanski, Tomasz; Silva, Maria Luiza M.; Land, Marcelo G.P.

    2016-01-01

    An increasing number of evidences suggest a genetic predisposition in acute lymphoblastic leukemia (ALL) that might favor the occurrence of the driver genetic alterations. Such genetic background might also translate into phenotypic alterations of residual hematopoietic cells. Whether such phenotypic alterations are present in bone marrow (BM) cells from childhood B-cell precursor (BCP)-ALL remains to be investigated. Here we analyzed the immunophenotypic profile of BM and peripheral blood (PB) maturing/matured neutrophils from 118 children with BCP-ALL and their relationship with the features of the disease. Our results showed altered neutrophil phenotypes in most (77%) BCP-ALL cases. The most frequently altered marker was CD10 (53%), followed by CD33 (34%), CD13 (15%), CD15/CD65 (10%) and CD123 (7%). Of note, patients with altered neutrophil phenotypes had younger age (p = 0.03) and lower percentages of BM maturing neutrophils (p = 0.004) together with greater BM lymphocyte (p = 0.04), and mature B-cell (p = 0.03) counts. No significant association was found between an altered neutrophil phenotype and other disease features. These findings point out the potential existence of an altered residual hematopoiesis in most childhood BCP-ALL cases. PMID:27028865

  17. Isolation and amino acid sequence of crustacean hyperglycemic hormone precursor-related peptides.

    PubMed

    Tensen, C P; Verhoeven, A H; Gaus, G; Janssen, K P; Keller, R; Van Herp, F

    1991-01-01

    The crustacean hyperglycemic hormone (CHH) is synthesized as part of a larger preprohormone in which the sequence of CHH is N-terminally flanked by a peptide for which the name CPRP (CHH precursor-related peptide) is proposed. Both CHH and CPRP are present in the sinus gland, the neurohemal organ of neurosecretory cells located in the eyestalk of decapod crustaceans. This paper describes the isolation and sequence analysis of CPRPs isolated from sinus glands of the crab Carcinus maenas, the crayfish Orconectes limosus and the lobster Homarus americanus. The published sequence of "peptide H" isolated from the land crab, Cardisoma carnifex, has now been recognized as a CPRP in this species. Sequence comparison reveals a high level of identity for the N-terminal region (residues 1-13) between all four peptides, while identity in the C-terminal domain is high between lobster and crayfish CPRP on the one hand, and between both crab species on the other. Conserved N-terminal residues include a putative monobasic processing site at position 11, which suggests that CPRP may be a biosynthetic intermediate from which a potentially bioactive decapeptide can be derived.

  18. Solvothermal synthesis of nanocrystalline copper nitride from an energetically unstable copper azide precursor.

    PubMed

    Choi, Jonglak; Gillan, Edward G

    2005-10-17

    Nonaqueous solvothermal chemical reactions have found extensive utility in the growth of inorganic non-oxide materials. This report describes the successful use of organic solvothermal environments to synthesize energetically unstable copper azide precursors that are then decomposed in situ to crystalline metastable copper nitride at temperatures below 200 degrees C. A comparison of Cu3N products formed from nonpolar (toluene) and coordinating (THF) solvents is described. The cubic Cu3N products are nanocrystalline with aggregated particle-like extended structures and were characterized by X-ray diffraction, electron microscopy, IR spectroscopy, and mass spectrometry. The thermal stability and composition of Cu3N was examined by thermogravimetric analysis and bulk elemental analysis. The particle surfaces contain bound residual solvent species that can be removed by heating. The poorly coordinating solvent, toluene, lead to a more crystalline product containing less residual organic content. Benchtop reactions were performed to follow the temporal formation and decomposition of metal azide intermediates. These studies provided more detailed information on the progression of metal azide to metal nitride materials in a solvothermal environment.

  19. Analysis of Membrane Topology and Identification of Essential Residues for the Yeast Endoplasmic Reticulum Inositol Acyltransferase Gwt1p

    PubMed Central

    Sagane, Koji; Umemura, Mariko; Ogawa-Mitsuhashi, Kaoru; Tsukahara, Kappei; Yoko-o, Takehiko; Jigami, Yoshifumi

    2011-01-01

    Glycosylphosphatidylinositol (GPI) is a post-translational modification that anchors cell surface proteins to the plasma membrane, and GPI modifications occur in all eukaryotes. Biosynthesis of GPI starts on the cytoplasmic face of the endoplasmic reticulum (ER) membrane, and GPI precursors flip from the cytoplasmic side to the luminal side of the ER, where biosynthesis of GPI precursors is completed. Gwt1p and PIG-W are inositol acyltransferases that transfer fatty acyl chains to the inositol moiety of GPI precursors in yeast and mammalian cells, respectively. To ascertain whether flipping across the ER membrane occurs before or after inositol acylation of GPI precursors, we identified essential residues of PIG-W and Gwt1p and determined the membrane topology of Gwt1p. Guided by algorithm-based predictions of membrane topology, we experimentally identified 13 transmembrane domains in Gwt1p. We found that Gwt1p, PIG-W, and their orthologs shared four conserved regions and that these four regions in Gwt1p faced the luminal side of the ER membrane. Moreover, essential residues of Gwt1p and PIG-W faced the ER lumen or were near the luminal edge of transmembrane domains. The membrane topology of Gwt1p suggested that inositol acylation occurred on the luminal side of the ER membrane. Rather than stimulate flipping of the GPI precursor across the ER membrane, inositol acylation of GPI precursors may anchor the precursors to the luminal side of the ER membrane, preventing flip-flops. PMID:21367863

  20. Potential hazards of fumigant residues.

    PubMed Central

    Fishbein, L

    1976-01-01

    A spectrum of fumigants (primarily ethylene dibromide, 1,2-dibromo-3-chloropropane, ethylene oxide, symdibromotetetrachloroethane, 1,3-dichloropropene, dichlorovos, carbon tetrachloride, methyl bromide) as well as their degradation products in foodstuffs and soil have been examined mainly in regard to the potential mutagenicity of their residues. PMID:789068

  1. Solidification process for sludge residue

    SciTech Connect

    Pearce, K.L.

    1998-09-10

    This report investigates the solidification process used at 100-N Basin to solidify the N Basin sediment and assesses the N Basin process for application to the K Basin sludge residue material. This report also includes a discussion of a solidification process for stabilizing filters. The solidified matrix must be compatible with the Environmental Remediation Disposal Facility acceptance criteria.

  2. Leptogenesis and residual CP symmetry

    NASA Astrophysics Data System (ADS)

    Chen, Peng; Ding, Gui-Jun; King, Stephen F.

    2016-03-01

    We discuss flavour dependent leptogenesis in the framework of lepton flavour models based on discrete flavour and CP symmetries applied to the type-I seesaw model. Working in the flavour basis, we analyse the case of two general residual CP symmetries in the neutrino sector, which corresponds to all possible semi-direct models based on a preserved Z 2 in the neutrino sector, together with a CP symmetry, which constrains the PMNS matrix up to a single free parameter which may be fixed by the reactor angle. We systematically study and classify this case for all possible residual CP symmetries, and show that the R-matrix is tightly constrained up to a single free parameter, with only certain forms being consistent with successful leptogenesis, leading to possible connections between leptogenesis and PMNS parameters. The formalism is completely general in the sense that the two residual CP symmetries could result from any high energy discrete flavour theory which respects any CP symmetry. As a simple example, we apply the formalism to a high energy S 4 flavour symmetry with a generalized CP symmetry, broken to two residual CP symmetries in the neutrino sector, recovering familiar results for PMNS predictions, together with new results for flavour dependent leptogenesis.

  3. A single gamma-carboxyglutamic acid residue in a novel cysteine-rich secretory protein without propeptide.

    PubMed

    Hansson, Karin; Thämlitz, Ann-Marie; Furie, Bruce; Furie, Barbara C; Stenflo, Johan

    2006-10-24

    Gamma-glutamyl carboxylase catalyzes the modification of specific glutamyl residues to gamma-carboxyglutamyl (Gla) residues in precursor proteins that possess the appropriate gamma-carboxylation recognition signal within the propeptide region. We describe the immunopurification and first biochemical characterization of an invertebrate high molecular weight Gla-containing protein with homologues in mammals. The protein, named GlaCrisp, was isolated from the venom of the marine cone snail Conus marmoreus. GlaCrisp gave intense signals in Western blot experiments employing the Gla-specific antibody M3B, and the presence of Gla was chemically confirmed by amino acid analysis after alkaline hydrolysis. Characterization of a full-length cDNA clone encoding GlaCrisp deduced a precursor containing an N-terminal signal peptide but, unlike other Gla-containing proteins, no apparent propeptide. The predicted mature protein of 265 amino acid residues showed considerable sequence similarity to the widely distributed cysteine-rich secretory protein family and closest similarity (65% identity) to the recently described substrate-specific protease Tex31. In addition, two cDNA clones encoding the precursors of two isoforms of GlaCrisp were identified. The predicted precursor isoforms differed at three amino acid positions (-6, 9, and 25). Analysis by Edman degradation and nanoelectrospray ionization mass spectrometry, before and after methyl esterfication, identified a Gla residue at amino acid position 9 in GlaCrisp. This is the first example of a Gla-containing protein without an obvious gamma-carboxylation recognition site. The results define a new class of Gla proteins and support the notion that gamma-carboxylation of glutamyl residues is phylogenetically older than blood coagulation and the vertebrate lineage.

  4. Partitioning Tungsten between Matrix Precursors and Chondrule Precursors through Relative Settling

    NASA Astrophysics Data System (ADS)

    Hubbard, Alexander

    2016-08-01

    Recent studies of chondrites have found a tungsten isotopic anomaly between chondrules and matrix. Given the refractory nature of tungsten, this implies that W was carried into the solar nebula by at least two distinct families of pre-solar grains. The observed chondrule/matrix split requires that the distinct families were kept separate during the dust coagulation process, and that the two families of grain interacted with the chondrule formation mechanism differently. We take the co-existence of different families of solids in the same general orbital region at the chondrule-precursor size as given, and explore the requirements for them to have interacted with the chondrule formation process at significantly different rates. We show that this sorting of families of solids into chondrule- and matrix-destined dust had to have been at least as powerful a sorting mechanism as the relative settling of aerodynamically distinct grains at least two scale heights above the midplane. The requirement that the chondrule formation mechanism was correlated in some fashion with a dust-grain sorting mechanism argues strongly for spatially localized chondrule formation mechanisms such as turbulent dissipation in non-thermally ionized disk surface layers, and argues against volume-filling mechanisms such as planetesimal bow shocks.

  5. Thin film solar cells by selenization sulfurization using diethyl selenium as a selenium precursor

    SciTech Connect

    Dhere, Neelkanth G.; Kadam, Ankur A.

    2009-12-15

    A method of forming a CIGSS absorber layer includes the steps of providing a metal precursor, and selenizing the metal precursor using diethyl selenium to form a selenized metal precursor layer (CIGSS absorber layer). A high efficiency solar cell includes a CIGSS absorber layer formed by a process including selenizing a metal precursor using diethyl selenium to form the CIGSS absorber layer.

  6. Experimental observation of precursor solitons in a flowing complex plasma

    NASA Astrophysics Data System (ADS)

    Jaiswal, Surabhi; Bandyopadhyay, P.; Sen, A.

    2016-04-01

    The excitation of precursor solitons ahead of a rapidly moving object in a fluid, a spectacular phenomenon in hydrodynamics that has often been observed ahead of moving ships, has surprisingly not been investigated in plasmas where the fluid model holds good for low frequency excitations such as ion acoustic waves. In this Rapid Communication we report an experimental observation of precursor solitons in a flowing dusty plasma. The nonlinear solitary dust acoustic waves (DAWs) are excited by a supersonic mass flow of the dust particles over an electrostatic potential hill. In a frame where the fluid is stationary and the hill is moving the solitons propagate in the upstream direction as precursors while wake structures consisting of linear DAWs are seen to propagate in the downstream region. A theoretical explanation of these excitations based on the forced Korteweg-deVries model equation is provided and their practical implications in situations involving a charged object moving in a plasma are discussed.

  7. Experimental observation of precursor solitons in a flowing complex plasma.

    PubMed

    Jaiswal, Surabhi; Bandyopadhyay, P; Sen, A

    2016-04-01

    The excitation of precursor solitons ahead of a rapidly moving object in a fluid, a spectacular phenomenon in hydrodynamics that has often been observed ahead of moving ships, has surprisingly not been investigated in plasmas where the fluid model holds good for low frequency excitations such as ion acoustic waves. In this Rapid Communication we report an experimental observation of precursor solitons in a flowing dusty plasma. The nonlinear solitary dust acoustic waves (DAWs) are excited by a supersonic mass flow of the dust particles over an electrostatic potential hill. In a frame where the fluid is stationary and the hill is moving the solitons propagate in the upstream direction as precursors while wake structures consisting of linear DAWs are seen to propagate in the downstream region. A theoretical explanation of these excitations based on the forced Korteweg-deVries model equation is provided and their practical implications in situations involving a charged object moving in a plasma are discussed. PMID:27176247

  8. Testosterone precursors: use and abuse in pediatric athletes.

    PubMed

    Smurawa, Troy M; Congeni, Joseph A

    2007-08-01

    The dietary supplements androstenedione, dehydroepiandrosterone, and androstenediol are precursors in the endogenous production of testosterone. The efficacy and safety of these prohormones are not well established but are promoted to have the same androgenic effects on building muscle mass and strength as anabolic-androgenic steroids. Studies have demonstrated repeatedly that acute and long-term administration of these oral testosterone precursors does not effectively increase serum testosterone levels and fails to produce any significant changes in lean body mass, muscle strength, or performance improvement compared with placebo. The Anabolic Steroid Control Act of 2004 lists androstenedione as a schedule III controlled substance, and it is regulated by the U.S. Food and Drug Administration. Testosterone precursors are banned by most major sports organizations.

  9. Effect of precursor solution dark incubation on gold nanorods morphology

    NASA Astrophysics Data System (ADS)

    Abdelrasoul, Gaser N.; Scotto, Marco; Cingolani, Roberto; Diaspro, Alberto; Athanassiou, Athanassia; Pignatelli, Francesca

    2012-12-01

    Gold nanorods were synthesized in an aqueous solution of hexadecyltrimethylammonium bromide via a combination of chemical reduction and UV photoirradiation. Gold ligand complexes, present in the stock solution, are initially reduced, by ascorbic acid as mild reducing agent. The gold ions nucleation and colloid growth proceeds then by subsequent UV irradiation of the so-obtained precursor solution. We present a systematic study of the effect of incubation of the precursor solution on the dispersion state and aspect ratio of the produced nanorods. Incubation of the precursor solution allows the synthesis of higher aspect ratio nanorods with narrower size distribution compared to those obtained without incubation. We propose a mechanism for the gold nanorods formation including two stages, a nucleation and a diffusive growth. This allows us to explain the synthesis improvement as a consequence of the increase in the size of the gold ligand complexes aggregates, leading to a decrease of the nanorods growth rate.

  10. Differentiating N-terminal aspartic and isoaspartic acid residues in peptides.

    PubMed

    Sargaeva, Nadezda P; Lin, Cheng; O'Connor, Peter B

    2011-09-01

    Formation of isoaspartic acid (isoAsp) is a common modification of aspartic acid (Asp) or asparagine (Asn) residue in proteins. Differentiation of isoAsp and Asp residues is a challenging task owing to their similar properties and identical molecular mass. It was recently shown that they can be differentiated using ion-electron or ion-ion interaction fragmentation methods (ExD) because these methods provide diagnostic fragments c + 57 and z(•) - 57 specific to the isoAsp residue. To date, however, the presence of such fragments has not been explored on peptides with an N-terminal isoAsp residue. To address this question, several N-terminal isoAsp-containing peptides were analyzed using ExD methods alone or combined with chromatography. A diagnostic fragment [M + 2H - 74](+•) was observed for the doubly charged precursor ions with N-terminal isoAsp residues. For some peptides, identification of the N-terminal isoAsp residue was challenging because of the low diagnostic ion peak intensity and the presence of interfering peaks. Supplemental activation was used to improve diagnostic ion detection. Further, N-terminal acetylation was offered as a means to overcome the interference problem by shifting the diagnostic fragment peak to [M + 2H - 116](+•).

  11. Research of Hydro-Geological Precursors of Earthquakes in Armenia

    NASA Astrophysics Data System (ADS)

    Pashayan, R.

    2007-12-01

    The observations of hydro-geological regime of underground waters in observed boreholes began in Armenia in 1986. Now these work is concentrated in National Seismic Service. For a long time observations are carried out studying several parameters (debit, temperature, chemical and gas composition) in several deposits of carbon mineral waters of Armenia. The interpretation of materials shows that that a number of strong and medium-strength earthquakes are accompanied by anomal changes in the level of underground waters. Regarding mineral waters, in connection with earthquakes some parameters are immediately changed: debit, temperature, chemical and gas composition. The study of hydrogeodynamic characteristics of precursors specify that the quantity of registered hydrogeodynamic precursors decreases with the increase of epicentrical distance. The majority of precursors is registered at the distance of 200 km from epicenter. There is a tendency of gradual increase of time and amplitude of a precursor of an earthquake depending on the rise of magnitude and epicentral distance. The behaviour of hydrogeodynamic precursors depends on the angle between the faults, to which this or that borehole reaches; with increase of this angle the deformation in the zone of the fault during the preparation of earthquakes is stronger, than in terms of small angles. 1. S1 2. Earthquake processes, Precursors and Forecasts 3. Garni Geophysical Observatory of the National Academy of Sciences of Armenia, 375019, Yerevan, Republic of Armenia, email: hakhleon@sci.am 4. O 5. 10808801 6. Artavazd Payment Type: select 'Purchase Order' PO Number: AGU WAIVER Billing Address: Enter Your Institution City: Enter Your City Country Code: Enter Your Country Name: Enter Your Name Phone: Enter Your Telephone Number

  12. 40 CFR 1065.705 - Residual and intermediate residual fuel.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... specifications for fuels meeting the definition of residual fuel in 40 CFR 80.2, including fuels marketed as... by reference in § 1065.1010). (2) Phosphorus is at or below 15 mg per kg of fuel based on the... 0.15 ISO 6245. Water, max (m3/m3) % 0.5 0.5 0.5 0.5 0.5 ISO 3733. Sulfur, max (kg/kg) % 3.50 4.00...

  13. 40 CFR 1065.705 - Residual and intermediate residual fuel.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... specifications for fuels meeting the definition of residual fuel in 40 CFR 80.2, including fuels marketed as... ISO 6245. Water, max (m3/m3)% 0.5 0.5 0.5 0.5 0.5 ISO 3733. Sulfur, max (kg/kg)% 3.50 4.00 4.50 4.50 4... the elements zinc, phosphorus, or calcium is at or below the specified limits. We consider a fuel...

  14. 40 CFR 1065.705 - Residual and intermediate residual fuel.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... specifications for fuels meeting the definition of residual fuel in 40 CFR 80.2, including fuels marketed as... ISO 6245. Water, max (m3/m3)% 0.5 0.5 0.5 0.5 0.5 ISO 3733. Sulfur, max (kg/kg)% 3.50 4.00 4.50 4.50 4... the elements zinc, phosphorus, or calcium is at or below the specified limits. We consider a fuel...

  15. Direct observation of optical precursors in a cold potassium gas

    NASA Astrophysics Data System (ADS)

    Jeong, Heejeong

    This thesis considers how an electromagnetic field propagates through a dispersive linear dielectric in the case when the field is turned on suddenly. It has been predicted nearly 100 years ago that the point in the waveform where the field first turns on (the front) propagates precisely at the speed of light in vacuum. Furthermore, it is predicted that distinct wave-packets develop after the front, but before the arrival of the main part of the field (the main signal). These wave-packets are known as optical precursors. It was believed that precursors are an ultra-fast phenomena, persisting only for a few optical cycles, and that they have an exceedingly small amplitude. I describe a method to increase the duration of optical precursors into the nanosecond range using a dielectric with a narrow resonance. I also show how to increase the precursor amplitude by tuning the carrier frequency of the field near the resonance frequency of the oscillators making up the dielectric medium. The field emerging from the dielectric consists of a several-nanosecond-long spike occurring immediately after the front with near 100% transmission, which subsequently decays to a constant value expected from Beer's Law of absorption. I demonstrate, using a modern asymptotic theory, that the spike consists of both the Sommerfeld and Brillouin precursors. Thus, my measurement is the first direct observation of optical precursors. The precursor research might be useful for imaging applications requiring penetrating optical radiation, such as in biological systems, or in optical communication systems. While the asymptotic theory explains qualitatively my observations, I find that there are large quantitative disagreements. I hypothesize that these errors are due to the fact that I use a weakly-dispersive narrow-resonance medium for which this theory has never been tested. I suggest empirical fixes to the theory by comparison to my data. I also compare the asymptotic theory and data to a

  16. Impact of delayed neutron precursor mobility in fissile solution systems

    SciTech Connect

    Kiedrowski, B. C.

    2012-07-01

    A research version of the Monte Carlo software package MCNP6 is modified to incorporate advection and diffusion of delayed neutron precursors, resulting in the emission of delayed neutrons at locations different from the original fission sites. Results of two test problems, a pipe carrying flowing fissile solution and a sphere of fissile solution with precursor diffusion, show that the fission product mobility tends to perturb the fundamental mode, has a negative reactivity effect, and, perhaps most importantly, causes a decrease in the effective delayed neutron fraction. (authors)

  17. Synthesis of GAP and PAMMO Homopolymers from Mesylate Polymeric Precursors

    NASA Astrophysics Data System (ADS)

    Mura, Claudio; Fruci, Stefania; Lamia, Pietro; Cappello, Miriam; Filippi, Sara; Polacco, Giovanni

    2016-04-01

    In azidic binders for solid propellants, the N3 functionality is introduced by substitution of a halogen or tosyl group, but recently the mesyl group has been suggested as an alternative. The mesylate group has two advantages, mainly related to its small dimensions and low cost. Poly(glycidyl azide) and poly 3-azidomethyl-3-methyl oxetane were prepared by using both tosylate and mesylate precursors. The azidation kinetics were studied at three different temperatures while keeping all other operating parameters the same. The results confirmed the good potential of the mesylate precursors for the production of azidic binders.

  18. The dynamo basis of solar cycle precursor schemes

    NASA Astrophysics Data System (ADS)

    Charbonneau, Paul; Barlet, Guillaume

    2011-02-01

    We investigate the dynamo underpinning of solar cycle precursor schemes based on direct or indirect measures of the solar surface magnetic field. We do so for various types of mean-field-like kinematic axisymmetric dynamo models, where amplitude fluctuations are driven by zero-mean stochastic forcing of the dynamo number controlling the strength of the poloidal source term. In all stochastically forced models considered, the surface poloidal magnetic field is found to have precursor value only if it feeds back into the dynamo loop, which suggests that accurate determination of the magnetic flux budget of the solar polar fields may hold the key to dynamo model-based cycle forecasting.

  19. Generation of Vibrationally Excited HCP from a Stable Synthetic Precursor

    NASA Astrophysics Data System (ADS)

    Hull, Alexander W.; Jiang, Jun; Erickson, Trevor J.; Womack, Carrie; Nava, Matthew; Cummins, Christopher; Field, Robert W.

    2015-06-01

    HCP belongs to a class of reactive small molecules with much interest to spectroscopists. It bears certain similarities to HCN, including a strong {A}(bent) - {X}(linear) ultraviolet transition, associated with the HCP-HPC isomerization pathway. HCP has traditionally been generated by the in situ reaction of PH_3 and acetylene. In this talk, we will discuss a recently developed synthetic precursor molecule, 1,1-((triphenylphosphoranylidene)methyl)-9,10-phosphanoanthracene. At temperatures above 200 degrees Celsius, this precursor is thought to release HCP in a vibrationally excited state. We will present preliminary spectra on this system obtained by LIF and chirped pulse millimeter wave spectroscopy.

  20. Recombinant pronapin precursor produced in Pichia pastoris displays structural and immunologic equivalent properties to its mature product isolated from rapeseed.

    PubMed

    Palomares, Oscar; Monsalve, Rafael I; Rodríguez, Rosalía; Villalba, Mayte

    2002-05-01

    2S albumin storage proteins from rapeseed (Brassica napus), called napins, consist of two different polypeptide chains linked by disulphide bridges, which are derived by proteolytic cleavage from a single precursor. The precursor form of the napin BnIb (proBnIb) has been cloned using a PCR strategy and sequenced. The amino-acid sequence deduced from the clone includes 31 residues of the small chain and 75 of the large chain, which are connected by the peptide Ser-Glu-Asn. Expression of the cDNA encoding proBnIb has been carried out in the methylotrophic yeast Pichia pastoris. The induced protein was secreted to the extracellular medium at a yield of 80 mg.L(-1) of culture and was purified by means of size-exclusion chromatography and reverse phase-HPLC. Recombinant proBnIb appeared properly folded as its molecular and spectroscopic properties were equivalent to those of the mature heterodimeric protein. As 2S albumin storage proteins from Brassicaceae have been shown to be type I allergy inducers, the immunological activity of the recombinant proBnIb was analysed as a measure of its structural integrity. The immunological properties of the recombinant precursor and the natural napin were indistinguishable by immunoblotting and ELISA inhibition using polyclonal antisera and sera of patients allergic to mustard and rapeseed. In conclusion, the recombinant expression of napin precursors in P. pastoris has been shown to be a successful method for high yield production of homogeneous and properly folded proteins whose polymorphism and complex maturation process limited hitherto their availability.

  1. Translocation arrest by reversible folding of a precursor protein imported into mitochondria. A means to quantitate translocation contact sites

    PubMed Central

    1989-01-01

    Passage of precursor proteins through translocation contact sites of mitochondria was investigated by studying the import of a fusion protein consisting of the NH2-terminal 167 amino acids of yeast cytochrome b2 precursor and the complete mouse dihydrofolate reductase. Isolated mitochondria of Neurospora crassa readily imported the fusion protein. In the presence of methotrexate import was halted and a stable intermediate spanning both mitochondrial membranes at translocation contact sites accumulated. The complete dihydrofolate reductase moiety in this intermediate was external to the outer membrane, and the 136 amino acid residues of the cytochrome b2 moiety remaining after cleavage by the matrix processing peptidase spanned both outer and inner membranes. Removal of methotrexate led to import of the intermediate retained at the contact site into the matrix. Thus unfolding at the surface of the outer mitochondrial membrane is a prerequisite for passage through translocation contact sites. The membrane-spanning intermediate was used to estimate the number of translocation sites. Saturation was reached at 70 pmol intermediate per milligram of mitochondrial protein. This amount of translocation intermediates was calculated to occupy approximately 1% of the total surface of the outer membrane. The morphometrically determined area of close contact between outer and inner membranes corresponded to approximately 7% of the total outer membrane surface. Accumulation of the intermediate inhibited the import of other precursor proteins suggesting that different precursor proteins are using common translocation contact sites. We conclude that the machinery for protein translocation into mitochondria is present at contact sites in limited number. PMID:2529262

  2. Catalytic combustion of residual fuels

    NASA Technical Reports Server (NTRS)

    Bulzan, D. L.; Tacina, R. R.

    1981-01-01

    A noble metal catalytic reactor was tested using two grades of petroleum derived residual fuels at specified inlet air temperatures, pressures, and reference velocities. Combustion efficiencies greater than 99.5 percent were obtained. Steady state operation of the catalytic reactor required inlet air temperatures of at least 800 K. At lower inlet air temperatures, upstream burning in the premixing zone occurred which was probably caused by fuel deposition and accumulation on the premixing zone walls. Increasing the inlet air temperature prevented this occurrence. Both residual fuels contained about 0.5 percent nitrogen by weight. NO sub x emissions ranged from 50 to 110 ppm by volume at 15 percent excess O2. Conversion of fuel-bound nitrogen to NO sub x ranged from 25 to 50 percent.

  3. Pesticidal residues in animal tissues

    USGS Publications Warehouse

    DeWitt, J.B.; Menzie, C.M.; Adomaitis, V.A.; Reichel, W.L.

    1960-01-01

    Tests with penned starlings, rats, pheasants, and ducks indicated that each species differs in sensitivity to the various pesticides. Residues in tissues are proportional to the degree of exposure during area treatment and they are also found in animals shot six or more months after treatment. The presence of more than 20-30 ppm of DDT, 20 ppm of chlordan, and 6-20 ppm of heptachlor epoxide in quail tissues indicated that the birds had ingested lethal dosages of the pesticides.

  4. Calcination/dissolution residue treatment

    SciTech Connect

    Knight, R.C.; Creed, R.F.; Patello, G.K.; Hollenberg, G.W.; Buehler, M.F.; O`Rourke, S.M.; Visnapuu, A.; McLaughlin, D.F.

    1994-09-01

    Currently, high-level wastes are stored underground in steel-lined tanks at the Hanford site. Current plans call for the chemical pretreatment of these wastes before their immobilization in stable glass waste forms. One candidate pretreatment approach, calcination/dissolution, performs an alkaline fusion of the waste and creates a high-level/low-level partition based on the aqueous solubilities of the components of the product calcine. Literature and laboratory studies were conducted with the goal of finding a residue treatment technology that would decrease the quantity of high-level waste glass required following calcination/dissolution waste processing. Four elements, Fe, Ni, Bi, and U, postulated to be present in the high-level residue fraction were identified as being key to the quantity of high-level glass formed. Laboratory tests of the candidate technologies with simulant high-level residues showed reductive roasting followed by carbonyl volatilization to be successful in removing Fe, Ni, and Bi. Subsequent bench-scale tests on residues from calcination/dissolution processing of genuine Hanford Site tank waste showed Fe was separated with radioelement decontamination factors of 70 to 1,000 times with respect to total alpha activity. Thermodynamic analyses of the calcination of five typical Hanford Site tank waste compositions also were performed. The analyses showed sodium hydroxide to be the sole molten component in the waste calcine and emphasized the requirement for waste blending if fluid calcines are to be achieved. Other calcine phases identified in the thermodynamic analysis indicate the significant thermal reconstitution accomplished in calcination.

  5. Residue management at Rocky Flats

    SciTech Connect

    Olencz, J.

    1995-12-31

    Past plutonium production and manufacturing operations conducted at the Rocky Flats Environmental Technology Site (RFETS) produced a variety of plutonium-contaminated by-product materials. Residues are a category of these materials and were categorized as {open_quotes}materials in-process{close_quotes} to be recovered due to their inherent plutonium concentrations. In 1989 all RFETS plutonium production and manufacturing operations were curtailed. This report describes the management of plutonium bearing liquid and solid wastes.

  6. Residue gasification tests at TVA

    SciTech Connect

    Spencer, D.

    1984-11-01

    The Texaco gasification process was identified as an attractive way to utilise vacuum bottoms from the Exxon Donor Solvent liquefaction process to generate synthesis gas. This gas can then be upgraded to produce the hydrogen required by the EDS plant. Gasification tests were carried out at TVA's 200 t/day Muscle Shoals plant and are reported here. As a result, Texaco expects that a plant could be designed to handle EDS residue from any high-rank coal.

  7. Residual stresses in continuous graphite fiber Al metal matrix composites

    NASA Technical Reports Server (NTRS)

    Park, Hun Sub; Zong, Gui Sheng; Marcus, Harris L.

    1988-01-01

    The residual stresses in graphite fiber reinforced aluminum (Gr/Al) composites with various thermal histories are measured using X-ray diffraction (XRD) methods. The XRD stress analysis is based on the determination of lattice strains by precise measurements of the interplanar spacings in different directions of the sample. The sample is a plate consisting of two-ply P 100 Gr/Al 6061 precursor wires and Al 6061 overlayers. Prior to XRD measurement, the 6061 overlayers are electrochemically removed. In order to calibrate the relationship between stress magnitude and lattice spacing shift, samples of Al 6061 are loaded at varying stress levels in a three-point bend fixture, while the stresses are simultaneously determined by XRD and surface-attached strain gages. The stresses determined by XRD closely match those determined by the strain gages. Using these calibrations, the longitudinal residual stresses of P 100 Gr/Al 6061 composites are measured for various heat treatments, and the results are presented.

  8. Geotechnical characteristics of residual soils

    SciTech Connect

    Townsend, F.C.

    1985-01-01

    Residual soils are products of chemical weathering and thus their characteristics are dependent upon environmental factors of climate, parent material, topography and drainage, and age. These conditions are optimized in the tropics where well-drained regions produce reddish lateritic soils rich in iron and aluminum sesquioxides and kaolinitic clays. Conversely, poorly drained areas tend towards montmorillonitic expansive black clays. Andosols develop over volcanic ash and rock regions and are rich in allophane (amorphous silica) and metastable halloysite. The geological origins greatly affect the resulting engineering characteristics. Both lateritic soils and andosols are susceptible to property changes upon drying, and exhibit compaction and strength properties not indicative of their classification limits. Both soils have been used successfully in earth dam construction, but attention must be given to seepage control through the weathered rock. Conversely, black soils are unpopular for embankments. Lateritic soils respond to cement stabilization and, in some cases, lime stabilization. Andosols should also respond to lime treatment and cement treatments if proper mixing can be achieved. Black expansive residual soils respond to lime treatment by demonstrating strength gains and decreased expansiveness. Rainfall induced landslides are typical of residual soil deposits.

  9. Evaluation of residue drum storage safety risks

    SciTech Connect

    Conner, W.V.

    1994-06-17

    A study was conducted to determine if any potential safety problems exist in the residue drum backlog at the Rocky Flats Plant. Plutonium residues stored in 55-gallon drums were packaged for short-term storage until the residues could be processed for plutonium recovery. These residues have now been determined by the Department of Energy to be waste materials, and the residues will remain in storage until plans for disposal of the material can be developed. The packaging configurations which were safe for short-term storage may not be safe for long-term storage. Interviews with Rocky Flats personnel involved with packaging the residues reveal that more than one packaging configuration was used for some of the residues. A tabulation of packaging configurations was developed based on the information obtained from the interviews. A number of potential safety problems were identified during this study, including hydrogen generation from some residues and residue packaging materials, contamination containment loss, metal residue packaging container corrosion, and pyrophoric plutonium compound formation. Risk factors were developed for evaluating the risk potential of the various residue categories, and the residues in storage at Rocky Flats were ranked by risk potential. Preliminary drum head space gas sampling studies have demonstrated the potential for formation of flammable hydrogen-oxygen mixtures in some residue drums.

  10. Urinary excretion of morphine and biosynthetic precursors in mice

    PubMed Central

    Grobe, Nadja; Lamshöft, Marc; Orth, Robert G.; Dräger, Birgit; Kutchan, Toni M.; Zenk, Meinhart H.; Spiteller, Michael

    2010-01-01

    It has been firmly established that humans excrete a small but steady amount of the isoquinoline alkaloid morphine in their urine. It is unclear whether it is of dietary or endogenous origin. There is no doubt that a simple isoquinoline alkaloid, tetrahydropapaveroline (THP), is found in human and rodent brain as well as in human urine. This suggests a potential biogenetic relationship between both alkaloids. Unlabeled THP or [1,3,4-D3]-THP was injected intraperitoneally into mice and the urine was analyzed. This potential precursor was extensively metabolized (96%). Among the metabolites found was the phenol-coupled product salutaridine, the known morphine precursor in the opium poppy plant. Synthetic [7D]-salutaridinol, the biosynthetic reduction product of salutaridine, injected intraperitoneally into live animals led to the formation of [7D]-thebaine, which was excreted in urine. [N-CD3]-thebaine was also administered and yielded [N-CD3]-morphine and the congeners [N-CD3]-codeine and [N-CD3]-oripavine in urine. These results show for the first time that live animals have the biosynthetic capability to convert a normal constituent of rodents, THP, to morphine. Morphine and its precursors are normally not found in tissues or organs, presumably due to metabolic breakdown. Hence, only that portion of the isoquinoline alkaloids excreted in urine unmetabolized can be detected. Analysis of urine by high resolution-mass spectrometry proved to be a powerful method for tracking endogenous morphine and its biosynthetic precursors. PMID:20421505

  11. Methionine as a Precursor of Ethylene—Commentary

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lieberman et al. showed in a 1966 publication of Plant Physiology that methionine is a precursor of ethylene. It was the first paper that showed ethylene carbons are derived from carbons 3 and 4 of methionine. This paper catalyzed remarkable interest among plant biologists to elucidate the biosynth...

  12. Manganite perovskite ceramics, their precursors and methods for forming

    DOEpatents

    Payne, David Alan; Clothier, Brent Allen

    2015-03-10

    Disclosed are a variety of ceramics having the formula Ln.sub.1-xM.sub.xMnO.sub.3, where 0.Itoreq.x.Itoreq.1 and where Ln is La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or Y; M is Ca, Sr, Ba, Cd, or Pb; manganite precursors for preparing the ceramics; a method for preparing the precursors; and a method for transforming the precursors into uniform, defect-free ceramics having magnetoresistance properties. The manganite precursors contain a sol and are derived from the metal alkoxides: Ln(OR).sub.3, M(OR).sub.2 and Mn(OR).sub.2, where R is C.sub.2 to C.sub.6 alkyl or C.sub.3 to C.sub.9 alkoxyalkyl, or C.sub.6 to C.sub.9 aryl. The preferred ceramics are films prepared by a spin coating method and are particularly suited for incorporation into a device such as an integrated circuit device.

  13. Urinary excretion of morphine and biosynthetic precursors in mice.

    PubMed

    Grobe, Nadja; Lamshöft, Marc; Orth, Robert G; Dräger, Birgit; Kutchan, Toni M; Zenk, Meinhart H; Spiteller, Michael

    2010-05-01

    It has been firmly established that humans excrete a small but steady amount of the isoquinoline alkaloid morphine in their urine. It is unclear whether it is of dietary or endogenous origin. There is no doubt that a simple isoquinoline alkaloid, tetrahydropapaveroline (THP), is found in human and rodent brain as well as in human urine. This suggests a potential biogenetic relationship between both alkaloids. Unlabeled THP or [1,3,4-D(3)]-THP was injected intraperitoneally into mice and the urine was analyzed. This potential precursor was extensively metabolized (96%). Among the metabolites found was the phenol-coupled product salutaridine, the known morphine precursor in the opium poppy plant. Synthetic [7D]-salutaridinol, the biosynthetic reduction product of salutaridine, injected intraperitoneally into live animals led to the formation of [7D]-thebaine, which was excreted in urine. [N-CD(3)]-thebaine was also administered and yielded [N-CD(3)]-morphine and the congeners [N-CD(3)]-codeine and [N-CD(3)]-oripavine in urine. These results show for the first time that live animals have the biosynthetic capability to convert a normal constituent of rodents, THP, to morphine. Morphine and its precursors are normally not found in tissues or organs, presumably due to metabolic breakdown. Hence, only that portion of the isoquinoline alkaloids excreted in urine unmetabolized can be detected. Analysis of urine by high resolution-mass spectrometry proved to be a powerful method for tracking endogenous morphine and its biosynthetic precursors.

  14. ATF3 controls proliferation of osteoclast precursor and bone remodeling

    PubMed Central

    Fukasawa, Kazuya; Park, Gyujin; Iezaki, Takashi; Horie, Tetsuhiro; Kanayama, Takashi; Ozaki, Kakeru; Onishi, Yuki; Takahata, Yoshifumi; Yoneda, Yukio; Takarada, Takeshi; Kitajima, Shigetaka; Vacher, Jean; Hinoi, Eiichi

    2016-01-01

    Bone homeostasis is maintained by the sophisticated coupled actions of bone-resorbing osteoclasts and bone-forming osteoblasts. Here we identify activating transcription factor 3 (ATF3) as a pivotal transcription factor for the regulation of bone resorption and bone remodeling under a pathological condition through modulating the proliferation of osteoclast precursors. The osteoclast precursor-specific deletion of ATF3 in mice led to the prevention of receptor activator of nuclear factor-κB (RANK) ligand (RANKL)-induced bone resorption and bone loss, although neither bone volume nor osteoclastic parameter were markedly altered in these knockout mice under the physiological condition. RANKL-dependent osteoclastogenesis was impaired in vitro in ATF3-deleted bone marrow macrophages (BMM). Mechanistically, the deficiency of ATF3 impaired the RANKL-induced transient increase in cell proliferation of osteoclast precursors in bone marrow in vivo as well as of BMM in vitro. Moreover, ATF3 regulated cyclin D1 mRNA expression though modulating activator protein-1-dependent transcription in the osteoclast precursor, and the introduction of cyclin D1 significantly rescued the impairment of osteoclastogenesis in ATF3-deleted BMM. Therefore, these findings suggest that ATF3 could have a pivotal role in osteoclastogenesis and bone homeostasis though modulating cell proliferation under pathological conditions, thereby providing a target for bone diseases. PMID:27480204

  15. Glutamine: Precursor or nitrogen donor for citrulline synthesis?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although glutamine is considered the main precursor for citrulline synthesis, the current literature does not differentiate between the contribution of glutamine carbon skeleton, versus nonspecific nitrogen (i.e., ammonia) and carbon derived from glutamine oxidation. To elucidate the role of glutami...

  16. Process for producing ceramic nitrides and carbonitrides and their precursors

    DOEpatents

    Brown, Gilbert M.; Maya, Leon

    1988-01-01

    A process for preparing ceramic nitrides and carbonitrides in the form of very pure, fine particulate powder. Appropriate precursor is prepared by reacting a transition metal alkylamide with ammonia to produce a mixture of metal amide and metal imide in the form of an easily pyrolyzable precipitate.

  17. Boron nitride ceramics from molecular precursors: synthesis, properties and applications.

    PubMed

    Bernard, Samuel; Salameh, Chrystelle; Miele, Philippe

    2016-01-21

    Hexagonal boron nitride (h-BN) attracts considerable interest because its structure is similar to that of carbon graphite while it displays different properties which are of interest for environmental and green technologies. The polar nature of the B-N bond in sp(2)-bonded BN makes it a wide band gap insulator with different chemistry on its surface and particular physical and chemical properties such as a high thermal conductivity, a high temperature stability, a high resistance to corrosion and oxidation and a strong UV emission. It is chemically inert and nontoxic and has good environmental compatibility. h-BN also has enhanced physisorption properties due to the dipolar fields near its surface. Such properties are closely dependent on the processing method. Bottom-up approaches consist of transforming molecular precursors into non-oxide ceramics with retention of the structural units inherent to the precursor molecule. The purpose of the present review is to give an up-to-date overview on the most recent achievements in the preparation of h-BN from borazine-based molecular single-source precursors including borazine and 2,4,6-trichloroborazine through both vapor phase syntheses and methods in the liquid/solid state involving polymeric intermediates, called the Polymer-Derived Ceramics (PDCs) route. In particular, the effect of the chemistry, composition and architecture of the borazine-based precursors and derived polymers on the shaping ability as well as the properties of h-BN is particularly highlighted. PMID:26646607

  18. Quaternary amines as nitrosamine precursors: a role for consumer products?

    PubMed

    Kemper, Jerome M; Walse, Spencer S; Mitch, William A

    2010-02-15

    Nitrosamine formation has been associated with wastewater-impacted waters, but specific precursors within wastewater effluents have not been identified. Experiments indicated that nitrosamines form in low yields from quaternary amines, and that the nitrosamines form from the quaternary amines themselves, not just lower order amine impurities. Polymeric and benzylated quaternary amines were more potent precursors than monomeric quaternary alkylamines. Pretreatment of quaternary amines with ozone or free chlorine, which deactivate lower order amine impurities, did not significantly reduce nitrosamine formation. The nitrosamine formation pathway is unclear but experiments indicated that transformation of quaternary amines to lower order amine precursors via Hofmann elimination was not involved. Experiments suggest that the pathway may involve quaternary amine degradation by amidogen or chloramino radicals formed from chloramines. Quaternary amines are significant constituents of consumer products, including shampoos, detergents, and fabric softeners. Although quaternary amines may be removed by sedimentation during wastewater treatment, their importance should be evaluated on a case-by-case basis. The high loadings from consumer products may enable the portion not removed to serve as precursors. PMID:20085252

  19. Synthesis and use of a trifluoromethylated azomethine ylide precursor.

    PubMed

    Tran, Gaël; Meier, Robin; Harris, Lawrence; Browne, Duncan L; Ley, Steven V

    2012-12-21

    The presence of fluorous substituents can impart a dramatic effect on the efficacy of molecules used for a range of applications in society. Here, we describe the preparation and use of a new trifluoromethylated azomethine ylide precursor, which leads to a series of fluorinated pyrrolidine, 3-pyrroline, and pyrrole building blocks. PMID:23176732

  20. Environment Conscious, Biomorphic Ceramics from Pine and Jelutong Wood Precursors

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay; Yee, Bo-Moon; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    Environment conscious, biomorphic ceramics have been fabricated from pine and jelutong wood precursors. A carbonaceous preform is produced through wood pyrolysis and subsequent infiltration with oxides (ZrO2 sols) and liquid silicon to form ceramics. These biomorphic ceramics show a wide variety of microstructures, densities, and hardness behavior that are determined by the type of wood and infiltrants selected.

  1. Process for producing ceramic nitrides anc carbonitrides and their precursors

    DOEpatents

    Brown, G.M.; Maya, L.

    1987-02-25

    A process for preparing ceramic nitrides and carbon nitrides in the form of very pure, fine particulate powder. Appropriate precursors is prepared by reaching a transition metal alkylamide with ammonia to produce a mixture of metal amide and metal imide in the form of an easily pyrolyzable precipitate.

  2. Descriptive and Experimental Analyses of Potential Precursors to Problem Behavior

    ERIC Educational Resources Information Center

    Borrero, Carrie S. W.; Borrero, John C.

    2008-01-01

    We conducted descriptive observations of severe problem behavior for 2 individuals with autism to identify precursors to problem behavior. Several comparative probability analyses were conducted in addition to lag-sequential analyses using the descriptive data. Results of the descriptive analyses showed that the probability of the potential…

  3. College Student Stress: A Predictor of Eating Disorder Precursor Behaviors

    ERIC Educational Resources Information Center

    Shelton, Virginia L.; Valkyrie, Karena T.

    2010-01-01

    Eating disorders are compulsive behaviors that can consume a person's life to the point of becoming life threatening. Previous research found stress associated with eating disorders. College can be a stressful time. If stress predicted precursor behaviors to eating disorders, then counselors would have a better chance to help students sooner. This…

  4. NASA's Accident Precursor Analysis Process and the International Space Station

    NASA Technical Reports Server (NTRS)

    Groen, Frank; Lutomski, Michael

    2010-01-01

    This viewgraph presentation reviews the implementation of Accident Precursor Analysis (APA), as well as the evaluation of In-Flight Investigations (IFI) and Problem Reporting and Corrective Action (PRACA) data for the identification of unrecognized accident potentials on the International Space Station.

  5. RIVERBANK FILTRATION: FATE OF DBP PRECURSORS AND SELECTED MICROORGANISMS

    EPA Science Inventory

    The fate of disinfection by-product (DBP) precursors and selected microorganisms during riverbank filtration (RBF) was monitored at three different mid-Western drinking water utilities. At all three sites, filtration (RBF) was monitored at three different mid-Western drinking wa...

  6. Precursors for ornithine and citrulline synthesis in neonatal pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrulline (CIT) is an amino acid synthesized by gut and utilized for the synthesis of the conditionally essential amino acid arginine (ARG). In turn, the immediate precursor for CIT synthesis, ornithine (ORN), can originate from proline (PRO) and glutamine (GLN) via ornithine aminotransferase (OAT,...

  7. Glutamine: precursor or nitrogen donor for citrulline synthesis?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glutamine (Gln) is considered the main precursor for citrulline (Cit) synthesis, but no attempts have been made to differentiate the contribution of Gln carbon (Gln-C) skeleton vs. the nonspecific contribution through NH3 and CO2. To study the contribution of dietary Gln-N to the synthesis of Cit, t...

  8. Single-source precursors to ternary silver indium sulfide materials.

    PubMed

    Deivaraj, T C; Park, J H; Afzaal, M; O'Brien, P; Vittal, J J

    2001-11-21

    Compounds of type [(Ph3P)2AgIn(SC(O)R)4] (R = Me (1), Ph (2)) are excellent single-source precursors for AgInS2 bulk materials by pyrolysis and AgIn5S8 films by aerosol assisted chemical vapour deposition (AACVD). PMID:12240047

  9. Technical Note: Methionine, a precursor of methane in living plants

    NASA Astrophysics Data System (ADS)

    Lenhart, K.; Althoff, F.; Greule, M.; Keppler, F.

    2015-03-01

    When terrestrial plants were identified as producers of the greenhouse gas methane, much discussion and debate ensued not only about their contribution to the global methane budget but also with regard to the validity of the observation itself. Although the phenomenon has now become more accepted for both living and dead plants, the mechanism of methane formation in living plants remains to be elucidated and its precursor compounds to be identified. We made use of stable isotope techniques to verify the in vivo formation of methane, and, in order to identify the carbon precursor, 13C positionally labeled organic compounds were employed. Here we show that the amino acid L-methionine acts as a methane precursor in living plants. Employing 13C-labeled methionine clearly identified the sulfur-bound methyl group of methionine as a carbon precursor of methane released from lavender (Lavandula angustifolia). Furthermore, when lavender plants were stressed physically, methane release rates and the stable carbon isotope values of the emitted methane greatly increased. Our results provide additional support that plants possess a mechanism for methane production and suggest that methionine might play an important role in the formation of methane in living plants, particularly under stress conditions.

  10. Technical note: Methionine, a precursor of methane in living plants

    NASA Astrophysics Data System (ADS)

    Lenhart, K.; Althoff, F.; Greule, M.; Keppler, F.

    2014-11-01

    When terrestrial plants were identified as producers of the greenhouse gas methane, much discussion and debate ensued, not only about their contribution to the global methane budget, but also with regard to the validity of the observation itself. Although the phenomenon has now become more accepted for both living and dead plants, the mechanism of methane formation in living plants remains to be elucidated and its precursor compounds identified. We made use of stable isotope techniques to verify in vivo formation of methane and, in order to identify the carbon precursor, 13C-positionally labelled organic compounds were employed. Here we show that the amino acid L-methionine acts as a methane precursor in living plants. Employing 13C-labelled methionine clearly identified the sulphur-bound methyl group of methionine as a carbon precursor of methane released from lavender (Lavandula angustifolia). Furthermore, when lavender plants were stressed physically, methane release rates and the stable carbon isotope values of the emitted methane greatly increased. Our results provide additional support that plants possess a mechanism for methane production and suggest that methionine might play an important role in the formation of methane in living plants, particularly under stress conditions.

  11. Observation of laser driven supercritical radiative shock precursors.

    PubMed

    Bouquet, S; Stéhlé, C; Koenig, M; Chièze, J-P; Benuzzi-Mounaix, A; Batani, D; Leygnac, S; Fleury, X; Merdji, H; Michaut, C; Thais, F; Grandjouan, N; Hall, T; Henry, E; Malka, V; Lafon, J-P J

    2004-06-01

    We present a supercritical radiative shock experiment performed with the LULI nanosecond laser facility. Using targets filled with xenon gas at low pressure, the propagation of a strong shock with a radiative precursor is evidenced. The main measured shock quantities (electronic density and propagation velocity) are shown to be in good agreement with theory and numerical simulations. PMID:15245230

  12. Modelling Precursor Decay in AD-99.5 Alumnina

    NASA Astrophysics Data System (ADS)

    Manoj Simha, C. Hari; Bless, Stephan J.; Bedford, Anthony M.

    1997-07-01

    In this paper we present a simple model to explain the absence of precursor decay in the Coor's AD-99.5 Alumina ceramic, as shown by Grady in his plate impact experiments. The model is incorporated in the WONDY finite difference code. The simulations of Grady's experiments compare well with the results.

  13. Modelling precursor decay in AD-99.5 Alumina

    SciTech Connect

    Simha, C. Hari Manoj; Bless, S. J.; Bedford, A.

    1998-07-10

    In this paper we present a simple model to explain the absence of precursor decay in the Coor's AD-99 5 Alumina ceramic, as shown by Grady in his plate impact experiments. The model is incorporated into the Research EPIC 95 finite element code. The simulations compare well with Grady's results.

  14. Modelling precursor decay in AD-99.5 Alumina

    NASA Astrophysics Data System (ADS)

    Simha, C. Hari Manoj; Bless, S. J.; Bedford, A.

    1998-07-01

    In this paper we present a simple model to explain the absence of precursor decay in the Coor's AD-99 5 Alumina ceramic, as shown by Grady in his plate impact experiments. The model is incorporated into the Research EPIC 95 finite element code. The simulations compare well with Grady's results.

  15. Intramyocardial angiogenic cell precursors in nonischemic dilated cardiomyopathy.

    PubMed

    Arom, Kitipan V; Ruengsakulrach, Permyos; Belkin, Michael; Tiensuwan, Montip

    2009-08-01

    To determine the efficacy of intramyocardial injection of angiogenic cell precursors in nonischemic dilated cardiomyopathy, 35 patients with nonischemic dilated cardiomyopathy underwent injections of angiogenic cell precursors into the left ventricle (cell group). Seventeen patients with nonischemic dilated cardiomyopathy were matched from the heart failure database to form a control group that was treated medically. Angiogenic cell precursors were obtained from autologous blood, cultured in vitro, and injected into all free-wall areas of the left ventricle in the cell group. After these injections, New York Heart Association functional class improved significantly by 1.1 +/- 0.7 classes at 284.7 +/- 136.2 days, and left ventricular ejection fraction improved in 71.4% of patients (25/35); the mean increase in left ventricular ejection fraction was 4.4% +/- 10.6% at 192.7 +/- 135.1 days. Improved quality of life was demonstrated by better physical function, role-physical, general health, and vitality domains in a short-form health survey at the 3-month follow-up. In the control group, there were no significant improvements in left ventricular ejection fraction or New York Heart Association class which increased by 0.6 +/- 0.8 classes. It was concluded that intramyocardial angiogenic cell precursor injection is probably effective in the treatment of nonischemic dilated cardiomyopathy. PMID:19713335

  16. Developmental Dyslexia: Early Precursors, Neurobehavioral Markers, and Biological Substrates

    ERIC Educational Resources Information Center

    Benasich, April A., Ed.; Fitch, R. Holly, Ed.

    2012-01-01

    Understanding the precursors and early indicators of dyslexia is key to early identification and effective intervention. Now there's a single research volume that brings together the very latest knowledge on the earliest stages of dyslexia and the diverse genetic, neurobiological, and cognitive factors that may contribute to it. Based on findings…

  17. Solution precursor plasma deposition of nanostructured ZnO coatings

    SciTech Connect

    Tummala, Raghavender; Guduru, Ramesh K.; Mohanty, Pravansu S.

    2011-08-15

    Highlights: {yields} The solution precursor route employed is an inexpensive process with capability to produce large scale coatings at fast rates on mass scale production. {yields} It is highly capable of developing tailorable nanostructures. {yields} This technique can be employed to spray the coatings on any kind of substrates including polymers. {yields} The ZnO coatings developed via solution precursor plasma spray process have good electrical conductivity and reflectivity properties in spite of possessing large amount of particulate boundaries, porosity and nanostructured grains. -- Abstract: Zinc oxide (ZnO) is a wide band gap semiconducting material that has various applications including optical, electronic, biomedical and corrosion protection. It is usually synthesized via processing routes, such as vapor deposition techniques, sol-gel, spray pyrolysis and thermal spray of pre-synthesized ZnO powders. Cheaper and faster synthesis techniques are of technological importance due to increased demand in alternative energy applications. Here, we report synthesis of nanostructured ZnO coatings directly from a solution precursor in a single step using plasma spray technique. Nanostructured ZnO coatings were deposited from the solution precursor prepared using zinc acetate and water/isopropanol. An axial liquid atomizer was employed in a DC plasma spray torch to create fine droplets of precursor for faster thermal treatment in the plasma plume to form ZnO. Microstructures of coatings revealed ultrafine particulate agglomerates. X-ray diffraction confirmed polycrystalline nature and hexagonal Wurtzite crystal structure of the coatings. Transmission electron microscopy studies showed fine grains in the range of 10-40 nm. Observed optical transmittance ({approx}65-80%) and reflectivity ({approx}65-70%) in the visible spectrum, and electrical resistivity (48.5-50.1 m{Omega} cm) of ZnO coatings are attributed to ultrafine particulate morphology of the coatings.

  18. PESTICIDE RESIDUE RECOVERIES FROM SURFACE WIPES

    EPA Science Inventory

    Human exposure is a consequence of pesticide use indoors with a primary source resulting from residue deposition on household surfaces. Accurate measurements of surface residues is essential for estimating exposure from different routes. Various procedures have been developed ...

  19. 48 CFR 970.5001 - Residual powers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Residual powers. 970.5001 Section 970.5001 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY....5001 Residual powers....

  20. 48 CFR 250.104 - Residual powers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Residual powers. 250.104 Section 250.104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... Contractual Actions 250.104 Residual powers....

  1. 48 CFR 970.5001 - Residual powers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Residual powers. 970.5001 Section 970.5001 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY....5001 Residual powers....

  2. 48 CFR 250.104 - Residual powers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Residual powers. 250.104 Section 250.104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... Contractual Actions 250.104 Residual powers....

  3. 48 CFR 970.5001 - Residual powers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Residual powers. 970.5001 Section 970.5001 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY....5001 Residual powers....

  4. 48 CFR 1850.104 - Residual powers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Residual powers. 1850.104 Section 1850.104 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION... 1850.104 Residual powers....

  5. 48 CFR 1850.104 - Residual powers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Residual powers. 1850.104 Section 1850.104 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION... 1850.104 Residual powers....

  6. 48 CFR 1850.104 - Residual powers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Residual powers. 1850.104 Section 1850.104 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION... 1850.104 Residual powers....

  7. 48 CFR 250.104 - Residual powers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Residual powers. 250.104 Section 250.104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... Contractual Actions 250.104 Residual powers....

  8. 48 CFR 970.5001 - Residual powers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Residual powers. 970.5001 Section 970.5001 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY....5001 Residual powers....

  9. 48 CFR 250.104 - Residual powers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Residual powers. 250.104 Section 250.104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... Contractual Actions 250.104 Residual powers....

  10. 48 CFR 970.5001 - Residual powers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Residual powers. 970.5001 Section 970.5001 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY....5001 Residual powers....

  11. 48 CFR 250.104 - Residual powers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Residual powers. 250.104 Section 250.104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... Contractual Actions 250.104 Residual powers....

  12. Two Peptides Derived from the Nerve Growth Factor Precursor Are Biologically Active

    PubMed Central

    Dicou, Eleni; Pflug, Beth; Magazin, Marilyn; Lehy, Thérèse; Djakiew, Daniel; Ferrara, Pascual; Nerrière, Véronique; Harvie, Douglas

    1997-01-01

    This report provides evidence that the proregion of the NGF precursor protein contains two novel bioactive peptides. The presence of pairs of basic amino acid (aa) residues in the NGF proregion suggests that two or three peptides other than NGF may be generated by proteolytic cleavage. Synthetic peptides of 29 aa (LIP1) and 38aa (LIP2) corresponding to the sequences −71 to −43 and −40 to −3 of the proNGF, respectively, were used in this study. ELISA specific for these two peptides revealed their presence in the rat intestine. LIP1 was localized by immunohistochemistry in endocrine cells of the intestinal epithelium, and LIP2 was immunoprecipitated from an intestinal extract. We also provide evidence for the presence of specific receptors for LIP2 in several cell lines. Scatchard analysis indicated the presence of a low affinity binding site with a Kd of ∼10−7 M and a high affinity binding site of 10−9 M. Cross-linking studies revealed receptor forms of about 140 kD and 93 kD in a prostatic adenocarcinoma cell line. LIP1 and LIP2 induced rapid F-actin redistribution in PC12 cells within 2 min of incubation, which suggests a role of LIP1 and LIP2 in the process of neurite outgrowth. Furthermore, both propeptides induced rapid tyrosine phosphorylation of the Trk protein in both prostatic adenocarcinoma cells and PC12 cells, thus implicating trk in their mechanism of action. These results support our hypothesis that two peptides within the NGF precursor protein are biologically active. PMID:9015309

  13. Analysis and residue levels of forchlorfenuron (CPPU) in watermelons.

    PubMed

    Valverde, Antonio; Piedra, Luis; Aguilera, Ana; Boulaid, Mourad; Camacho, Francisco

    2007-01-01

    This paper describes the application of liquid chromatography-tandem mass spectrometry (LC/MS-MS) for analysis of residues of forchlorfenuron (CPPU), a new plant growth regulator, in watermelons, after a sample preparation step based on the buffered Quick, Easy, Cheap, Effective, Rugged and Safe extraction method. Analytical determinations were carried out in a triple quadrupole system fitted with an electrospray interphase operating in the positive ionisation mode (ESI+). Three simultaneous MS-MS transitions of the quasi-molecular ion m/z 248 (precursor ion) were monitored for data acquisition (248 > 129, 248 > 155, and 248 > 248), using the transition 248 > 129 for quantitation. Recovery studies on watermelons at levels of 1-200 microg/kg, performing five replicates at each level and using bracketing single-level calibration with matrix-matched standards for quantitation, gave forchlorfenuron mean recoveries ranging from 82 to 106% with relative standard deviations (RSD) lower than 18%. The limit of determination was established at 1 microg/kg. The method was applied to evaluate the persistence of forchlorfenuron residues in watermelons grown in plastic greenhouses, after applying an individual spray treatment to the flower ovary at the anthesis stage (45 mu g/flower and 60 mu g/flower for cv "Extazy" and cv "reina de corazones" watermelons, respectively). One month after treatment, 20 "Extazy" watermelon units (1.5-2 kg/unit) and 20 "Reina de corazones" watermelon units (4-5 kg/unit) were collected and analyzed individually. None of the samples contained forchlorfenuron residues higher than 1 microg/kg.

  14. 48 CFR 50.104 - Residual powers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Residual powers. 50.104... EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 50.104 Residual powers. This section prescribes standards and procedures for exercising residual powers under Pub. L....

  15. 9 CFR 311.39 - Biological residues.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Biological residues. 311.39 Section... Biological residues. Carcasses, organs, or other parts of carcasses of livestock shall be condemned if it is determined that they are adulterated because of the presence of any biological residues....

  16. 9 CFR 311.39 - Biological residues.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Biological residues. 311.39 Section... Biological residues. Carcasses, organs, or other parts of carcasses of livestock shall be condemned if it is determined that they are adulterated because of the presence of any biological residues....

  17. 9 CFR 311.39 - Biological residues.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Biological residues. 311.39 Section... Biological residues. Carcasses, organs, or other parts of carcasses of livestock shall be condemned if it is determined that they are adulterated because of the presence of any biological residues....

  18. 9 CFR 311.39 - Biological residues.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Biological residues. 311.39 Section... Biological residues. Carcasses, organs, or other parts of carcasses of livestock shall be condemned if it is determined that they are adulterated because of the presence of any biological residues....

  19. 48 CFR 50.104 - Residual powers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Residual powers. 50.104... EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 50.104 Residual powers. This section prescribes standards and procedures for exercising residual powers under Pub. L....

  20. 48 CFR 50.104 - Residual powers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Residual powers. 50.104... EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 50.104 Residual powers. This section prescribes standards and procedures for exercising residual powers under Pub. L....

  1. 48 CFR 50.104 - Residual powers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Residual powers. 50.104... EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 50.104 Residual powers. This section prescribes standards and procedures for exercising residual powers under Pub. L....

  2. 48 CFR 50.104 - Residual powers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Residual powers. 50.104... EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 50.104 Residual powers. This section prescribes standards and procedures for exercising residual powers under Pub. L....

  3. Australian lungfish neurohypophysial hormone genes encode vasotocin and [Phe2]mesotocin precursors homologous to tetrapod-type precursors.

    PubMed

    Hyodo, S; Ishii, S; Joss, J M

    1997-11-25

    In view of the well-established role of neurohypophysial hormones in osmoregulation of terrestrial vertebrates, lungfishes are a key group for study of the molecular and functional evolution of the hypothalamo-neurohypophysial system. Here we report on the primary structure of the precursors encoding vasotocin (VT) and [Phe2]mesotocin ([Phe2]MT) of the Australian lungfish, Neoceratodus forsteri. Genomic sequence analysis and Northern blot analysis confirmed that [Phe2]MT is a native oxytocin family peptide in the Australian lungfish, although it has been reported that the lungfish neurohypophysis contains MT. The VT precursor consists of a signal peptide, VT, that is connected to a neurophysin by a Gly-Lys-Arg sequence, and a copeptin moiety that includes a Leu-rich core segment and a glycosylation site. In contrast, the [Phe2]MT precursor does not contain a copeptin moiety. These structural features of the lungfish precursors are consistent with those in tetrapods, but different from those in teleosts where both VT and isotocin precursors contain a copeptin-like moiety without a glycosylation site at the carboxyl terminals of their neurophysins. Comparison of the exon/intron organization also supports homology of the lungfish [Phe2]MT gene with tetrapod oxytocin/MT genes, rather than with teleost isotocin genes. Moreover, molecular phylogenetic analysis shows that neurohypophysial hormone genes of the lungfish are closely related to those of the toad. The present results along with previous morphological findings indicate that the hypothalamo-neurohypophysial system of the lungfish has evolved along the tetrapod lineage, whereas the teleosts form a separate lineage, both within the class Osteichthyes.

  4. Catecholamine regulation of stromal precursors and hemopoietic stem cells in cytostatic myelosuppression.

    PubMed

    Dygai, A M; Khmelevskaya, E S; Skurikhin, E G; Pershina, O V; Andreeva, T V; Ermakova, N N

    2012-04-01

    Effects of a sympatholytic drug on bone marrow stromal and hemopoietic precursors were studied on the model of cyclophosphamide-induced myelosuppression. Sympatholytic treatment increased the content of hemopoietic stem cells of different classes in the bone marrow. Selective stimulation of differentiation of polypotent precursors into granulocyte-macrophage precursors was noted. Acceleration of proliferation and maturation of granulocytic precursors was observed at later terms during regeneration of the hemopoietic tissue. The sympatholytic inhibited proliferation of stromal precursors and reduced feeder activity of fibroblasts for granulocyte precursors.

  5. Process to recycle shredder residue

    DOEpatents

    Jody, Bassam J.; Daniels, Edward J.; Bonsignore, Patrick V.

    2001-01-01

    A system and process for recycling shredder residue, in which separating any polyurethane foam materials are first separated. Then separate a fines fraction of less than about 1/4 inch leaving a plastics-rich fraction. Thereafter, the plastics rich fraction is sequentially contacted with a series of solvents beginning with one or more of hexane or an alcohol to remove automotive fluids; acetone to remove ABS; one or more of EDC, THF or a ketone having a boiling point of not greater than about 125.degree. C. to remove PVC; and one or more of xylene or toluene to remove polypropylene and polyethylene. The solvents are recovered and recycled.

  6. Automating a residual gas analyzer

    NASA Technical Reports Server (NTRS)

    Petrie, W. F.; Westfall, A. H.

    1982-01-01

    A residual gas analyzer (RGA), a device for measuring the amounts and species of various gases present in a vacuum system is discussed. In a recent update of the RGA, it was shown that the use of microprocessors could revolutionize data acquisition and data reduction. This revolution is exemplified by the Inficon 1Q200 RGA which was selected to meet the needs of this update. The Inficon RGA and the Zilog microcomputer were interfaced in order the receive and format the digital data from the RGA. This automated approach is discussed in detail.

  7. Minimal residual disease analysis by eight-color flow cytometry in relapsed childhood acute lymphoblastic leukemia.

    PubMed

    Karawajew, Leonid; Dworzak, Michael; Ratei, Richard; Rhein, Peter; Gaipa, Giuseppe; Buldini, Barbara; Basso, Giuseppe; Hrusak, Ondrej; Ludwig, Wolf-Dieter; Henze, Günter; Seeger, Karl; von Stackelberg, Arend; Mejstrikova, Ester; Eckert, Cornelia

    2015-07-01

    Multiparametric flow cytometry is an alternative approach to the polymerase chain reaction method for evaluating minimal residual disease in treatment protocols for primary acute lymphoblastic leukemia. Given considerable differences between primary and relapsed acute lymphoblastic leukemia treatment regimens, flow cytometric assessment of minimal residual disease in relapsed leukemia requires an independent comprehensive investigation. In the present study we addressed evaluation of minimal residual disease by flow cytometry in the clinical trial for childhood relapsed acute lymphoblastic leukemia using eight-color flow cytometry. The major challenge of the study was to reliably identify low amounts of residual leukemic cells against the complex background of regeneration, characteristic of follow-up samples during relapse treatment. In a prospective study of 263 follow-up bone marrow samples from 122 patients with B-cell precursor acute lymphoblastic leukemia, we tested various B-cell markers, adapted the antibody panel to the treatment protocol, and evaluated its performance by a blinded parallel comparison with the polymerase chain reaction data. The resulting eight-color single-tube panel showed a consistently high overall concordance (P<0.001) and, under optimal conditions, sensitivity similar to that of the reference polymerase chain reaction method. Overall, evaluation of minimal residual disease by flow cytometry can be successfully integrated into the clinical management of relapsed childhood acute lymphoblastic leukemia either as complementary to the polymerase chain reaction or as an independent risk stratification tool. ALL-REZ BFM 2002 clinical trial information: NCT00114348.

  8. Whole-cell fungal transformation of precursors into dyes

    PubMed Central

    2010-01-01

    Background Chemical methods of producing dyes involve extreme temperatures and unsafe toxic compounds. Application of oxidizing enzymes obtained from fungal species, for example laccase, is an alternative to chemical synthesis of dyes. Laccase can be replaced by fungal biomass acting as a whole-cell biocatalyst with properties comparable to the isolated form of the enzyme. The application of the whole-cell system simplifies the transformation process and reduces the time required for its completion. In the present work, four fungal strains with a well-known ability to produce laccase were tested for oxidation of 17 phenolic and non-phenolic precursors into stable and non-toxic dyes. Results An agar-plate screening test of the organic precursors was carried out using four fungal strains: Trametes versicolor, Fomes fomentarius, Abortiporus biennis, and Cerrena unicolor. Out of 17 precursors, nine were transformed into coloured substances in the presence of actively growing fungal mycelium. The immobilized fungal biomass catalyzed the transformation of 1 mM benzene and naphthalene derivatives in liquid cultures yielding stable and non-toxic products with good dyeing properties. The type of fungal strain had a large influence on the absorbance of the coloured products obtained after 48-hour transformation of the selected precursors, and the most effective was Fomes fomentarius (FF25). Whole-cell transformation of AHBS (3-amino-4-hydroxybenzenesulfonic acid) into a phenoxazinone dye was carried out in four different systems: in aqueous media comprising low amounts of carbon and nitrogen source, in buffer, and in distilled water. Conclusions This study demonstrated the ability of four fungal strains belonging to the ecological type of white rot fungi to transform precursors into dyes. This paper highlights the potential of fungal biomass for replacing isolated enzymes as a cheaper industrial-grade biocatalyst for the synthesis of dyes and other commercially important

  9. Making Single-Source Precursors of Ternary Semiconductors

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius; Banger, Kulbindre K.

    2007-01-01

    A synthesis route has been developed for the commercial manufacture of single- source precursors of chalcopyrite semiconductor absorber layers of thin-film solar photovoltaic cells. A closely related class of single-source precursors of these semiconductors, and their synthesis routes, were reported in "Improved Single-Source Precursors for Solar-Cell Absorbers" (LEW-17445-1), NASA Tech Briefs, Vol. 31, No. 6 (June 2007), page 56. The present synthesis route is better suited to commercialization because it is simpler and involves the use of commercially available agents, yet offers the flexibility needed for synthesis of a variety of precursors. A single-source precursor of the type of interest here is denoted by the general formula L2M'(mu-ER)2M(ER)2, where L signifies a Lewis base; M signifies Al, In, or Ga; M' signifies Ag or Cu; R signifies an alkyl, aryl, silyl, or perfluorocarbon group; E signifies O, S, Se, or Te; and mu signifies a bridging ligand. This compound can be synthesized in a "one-pot" procedure from ingredients that are readily available from almost any chemical supplier. In a demonstration, the following synthesis was performed: Under anaerobic conditions, InCl3 was reacted with sodium ethanethiolate in methanol in a 1:4 molar ratio to afford the ionic stable intermediate compound Na+[In(SEt)4]- (where Et signifies ethyl group). After approximately 15 minutes, a heterogeneous solution of CuCl and the Lewis base PPh3 (where Ph signifies phenyl) in a 1:2 ratio in a mixture of CH3CN and CH2Cl2 was added directly to the freshly prepared Na+[In(SEt)4]-. After 24 hours, the reaction was essentially complete. The methanolic solution was concentrated, then the product was extracted with CH2Cl2, then the product was washed with dry ether and pentane. The product in its final form was a creamy white solid. Spectroscopic and elemental analysis confirmed that the product was (PPh3)2Cu(mu-SEt)2In(mu-SEt)2, which is known to be a precursor of the ternary

  10. Fiber-optic polymer residue monitor

    SciTech Connect

    Pfeifer, K.B.; Jarecki, R.L. Jr.; Dalton, T.J.

    1998-10-01

    Semiconductor processing tools that use a plasma to etch polysilicon or oxides produce residue polymers that build up on the exposed surfaces of the processing chamber. These residues are generally stressed and with time can cause flaking onto wafers resulting in yield loss. Currently, residue buildup is not monitored, and chambers are cleaned at regular intervals resulting in excess downtime for the tool. In addition, knowledge of the residue buildup rate and index of refraction is useful in determining the state of health of the chamber process. The authors have developed a novel optical fiber-based robust sensor that allows measurement of the residue polymer buildup while not affecting the plasma process.

  11. Managing residual limb hyperhidrosis in wounded warriors.

    PubMed

    Pace, Sarah; Kentosh, Joshua

    2016-06-01

    Residual limb dermatologic problems are a common concern among young active traumatic amputee patients who strive to maintain an active lifestyle. Hyperhidrosis of residual limbs is a recognized inciting factor that often contributes to residual limb dermatoses and is driven by the design of the prosthetic liner covering the residual limb. Treatment of hyperhidrosis in this population presents a unique challenge. Several accepted treatments of hyperhidrosis can offer some relief but have been limited by lack of results or side-effect profiles. Microwave thermal ablation has presented an enticing potential for residual limb hyperhidrosis. PMID:27416083

  12. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  13. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  14. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  15. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  16. RESIDUAL STRESSES IN 3013 CONTAINERS

    SciTech Connect

    Mickalonis, J.; Dunn, K.

    2009-11-10

    The DOE Complex is packaging plutonium-bearing materials for storage and eventual disposition or disposal. The materials are handled according to the DOE-STD-3013 which outlines general requirements for stabilization, packaging and long-term storage. The storage vessels for the plutonium-bearing materials are termed 3013 containers. Stress corrosion cracking has been identified as a potential container degradation mode and this work determined that the residual stresses in the containers are sufficient to support such cracking. Sections of the 3013 outer, inner, and convenience containers, in both the as-fabricated condition and the closure welded condition, were evaluated per ASTM standard G-36. The standard requires exposure to a boiling magnesium chloride solution, which is an aggressive testing solution. Tests in a less aggressive 40% calcium chloride solution were also conducted. These tests were used to reveal the relative stress corrosion cracking susceptibility of the as fabricated 3013 containers. Significant cracking was observed in all containers in areas near welds and transitions in the container diameter. Stress corrosion cracks developed in both the lid and the body of gas tungsten arc welded and laser closure welded containers. The development of stress corrosion cracks in the as-fabricated and in the closure welded container samples demonstrates that the residual stresses in the 3013 containers are sufficient to support stress corrosion cracking if the environmental conditions inside the containers do not preclude the cracking process.

  17. South Polar Residual Ice Cap

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This mosaic is composed of 18 Viking Orbiter images (6 each in red, green, and violet filters), acquired on September 28, 1977, during revolution 407 of Viking Orbiter 2. The south pole is located just off the lower left edge of the polar cap, and the 0 degree longitude meridian extends toward the top of the mosaic. The large crater near the right edge (named 'South') is about 100 km in diameter. These images were acquired during southern summer on Mars (Ls = 341 degrees); the sub-solar declination was 8 degrees S., and the south polar cap was nearing its final stage of retreat just prior to vernal equinox. The south residual cap is approximately 400 km across, and the exposed surface is thought to consist dominantly of carbon-dioxide frost. This is in contrast to the water-ice surface of the north polar residual cap. It is likely that water ice is present in layers that underlie the south polar cap and that comprise the surrounding layered terrains. Near the top of this image, irregular pits with sharp-rimmed cliffs appear 'etched', presumably by wind. A series of rugged mountains (extending toward the upper right corner of the image) are of unknown origin.

  18. Purification of neural precursor cells reveals the presence of distinct, stimulus-specific subpopulations of quiescent precursors in the adult mouse hippocampus.

    PubMed

    Jhaveri, Dhanisha J; O'Keeffe, Imogen; Robinson, Gregory J; Zhao, Qiong-Yi; Zhang, Zong Hong; Nink, Virginia; Narayanan, Ramesh K; Osborne, Geoffrey W; Wray, Naomi R; Bartlett, Perry F

    2015-05-27

    The activity of neural precursor cells in the adult hippocampus is regulated by various stimuli; however, whether these stimuli regulate the same or different precursor populations remains unknown. Here, we developed a novel cell-sorting protocol that allows the purification to homogeneity of neurosphere-forming neural precursors from the adult mouse hippocampus and examined the responsiveness of individual precursors to various stimuli using a clonal assay. We show that within the Hes5-GFP(+)/Nestin-GFP(+)/EGFR(+) cell population, which comprises the majority of neurosphere-forming precursors, there are two distinct subpopulations of quiescent precursor cells, one directly activated by high-KCl depolarization, and the other activated by norepinephrine (NE). We then demonstrate that these two populations are differentially distributed along the septotemporal axis of the hippocampus, and show that the NE-responsive precursors are selectively regulated by GABA, whereas the KCl-responsive precursors are selectively modulated by corticosterone. Finally, based on RNAseq analysis by deep sequencing, we show that the progeny generated by activating NE-responsive versus KCl-responsive quiescent precursors are molecularly different. These results demonstrate that the adult hippocampus contains phenotypically similar but stimulus-specific populations of quiescent precursors, which may give rise to neural progeny with different functional capacity.

  19. Whistler damping at oblique propagation - Laminar shock precursors

    NASA Technical Reports Server (NTRS)

    Gary, S. P.; Mellott, M. M.

    1985-01-01

    This paper addresses the collisionless damping of whistlers observed as precursors standing upstream of oblique, low-Mach number terrestrial bow shocks. The linear theory of electromagnetic waves in a homogeneous Vlasov plasma with Maxwellian distribution functions and a magnetic field is considered. Numerical solutions of the full dispersion equation are presented for whistlers propagating at an arbitrary angle with respect to the magnetic field. It is demonstrated that electron Landau damping attenuates oblique whistlers and that the parameter which determines this damping is beta-e. In a well-defined range of parameters, this theory provides damping lengths which are the same order of magnitude as those observed. Thus electron Landau damping is a plausible process in the dissipation of upstream whistlers. Nonlinear plasma processes which may contribute to precursor damping are also discussed, and criteria for distinguishing among these are described.

  20. Detection of hydrothermal precursors to large northern california earthquakes.

    PubMed

    Silver, P G; Valette-Silver, N J

    1992-09-01

    During the period 1973 to 1991 the interval between eruptions from a periodic geyser in Northern California exhibited precursory variations 1 to 3 days before the three largest earthquakes within a 250-kilometer radius of the geyser. These include the magnitude 7.1 Loma Prieta earthquake of 18 October 1989 for which a similar preseismic signal was recorded by a strainmeter located halfway between the geyser and the earthquake. These data show that at least some earthquakes possess observable precursors, one of the prerequisites for successful earthquake prediction. All three earthquakes were further than 130 kilometers from the geyser, suggesting that precursors might be more easily found around rather than within the ultimate rupture zone of large California earthquakes.

  1. The Accident Sequence Precursor program: Methods improvements and current results

    SciTech Connect

    Minarick, J.W.; Manning, F.M.; Harris, J.D.

    1987-01-01

    Changes in the US NRC Accident Sequence Precursor program methods since the initial program evaluations of 1969-81 operational events are described, along with insights from the review of 1984-85 events. For 1984-85, the number of significant precursors was consistent with the number observed in 1980-81, dominant sequences associated with significant events were reasonably consistent with PRA estimates for BWRs, but lacked the contribution due to small-break LOCAs previously observed and predicted in PWRs, and the frequency of initiating events and non-recoverable system failures exhibited some reduction compared to 1980-81. Operational events which provide information concerning additional PRA modeling needs are also described.

  2. Percolation-based precursors of transitions in extended systems

    NASA Astrophysics Data System (ADS)

    Rodríguez-Méndez, Víctor; Eguíluz M, Víctor M.; Hernández-García, Emilio; Ramasco, José J.

    2016-07-01

    Abrupt transitions are ubiquitous in the dynamics of complex systems. Finding precursors, i.e. early indicators of their arrival, is fundamental in many areas of science ranging from electrical engineering to climate. However, obtaining warnings of an approaching transition well in advance remains an elusive task. Here we show that a functional network, constructed from spatial correlations of the system’s time series, experiences a percolation transition way before the actual system reaches a bifurcation point due to the collective phenomena leading to the global change. Concepts from percolation theory are then used to introduce early warning precursors that anticipate the system’s tipping point. We illustrate the generality and versatility of our percolation-based framework with model systems experiencing different types of bifurcations and with Sea Surface Temperature time series associated to El Niño phenomenon.

  3. Fission-Based Electric Propulsion for Interstellar Precursor Missions

    SciTech Connect

    HOUTS,MICHAEL G.; LENARD,ROGER X.; LIPINSKI,RONALD J.; PATTON,BRUCE; POSTON,DAVID; WRIGHT,STEVEN A.

    1999-11-03

    This paper reviews the technology options for a fission-based electric propulsion system for interstellar precursor missions. To achieve a total {Delta}V of more than 100 km/s in less than a decade of thrusting with an electric propulsion system of 10,000s Isp requires a specific mass for the power system of less than 35 kg/kWe. Three possible configurations are described: (1) a UZrH-fueled,NaK-cooled reactor with a steam Rankine conversion system,(2) a UN-fueled gas-cooled reactor with a recuperated Brayton conversion system, and (3) a UN-fueled heat pipe-cooled reactor with a recuperated Brayton conversion system. All three of these systems have the potential to meet the specific mass requirements for interstellar precursor missions in the near term. Advanced versions of a fission-based electric propulsion system might travel as much as several light years in 200 years.

  4. Enzyme-triggered and self-cleaving fragrant alcohol precursors.

    PubMed

    Flachsmann, Felix; Gautschi, Markus; Bachmann, Jean-Pierre; Brunner, Gerhard

    2008-06-01

    The high volatility and water solubility of many natural perfumery alcohols leads to their rapid loss in fabric-care and personal-care applications. A dramatically enhanced substantivity is achieved by the use of fragrance precursors as controlled-release systems. In the first part of this article, we present multi-odorant precursors, in which the enzymatic cleavage of esters or carbonates of fragrant alcohols triggers subsequent steps leading to the release of fragrant ketones, lactones, and additional fragrant alcohols. In the second part, a study on oligocarbonates of fragrant alcohols is presented. Therein, the outstanding enzyme-independent performance of gluconolactone oligocarbonate 27 for the long-lasting release of (Z)-hex-3-en-1-ol is highlighted. We show that these polyfunctional compounds undergo complex rearrangements and intramolecular substitution reactions which lead to the observed release kinetics.

  5. Detection of hydrothermal precursors to large northern california earthquakes.

    PubMed

    Silver, P G; Valette-Silver, N J

    1992-09-01

    During the period 1973 to 1991 the interval between eruptions from a periodic geyser in Northern California exhibited precursory variations 1 to 3 days before the three largest earthquakes within a 250-kilometer radius of the geyser. These include the magnitude 7.1 Loma Prieta earthquake of 18 October 1989 for which a similar preseismic signal was recorded by a strainmeter located halfway between the geyser and the earthquake. These data show that at least some earthquakes possess observable precursors, one of the prerequisites for successful earthquake prediction. All three earthquakes were further than 130 kilometers from the geyser, suggesting that precursors might be more easily found around rather than within the ultimate rupture zone of large California earthquakes. PMID:17738277

  6. Organometallic precursors of nano-objects, a critical view.

    PubMed

    Cormary, Benoit; Dumestre, Frédéric; Liakakos, Nikolaos; Soulantica, Katerina; Chaudret, Bruno

    2013-09-21

    The synthesis of nanoparticles has experienced a huge development over the past 20 years. However, this development has remained relatively limited to a few classes of nanomaterials such as iron oxides, semi-conducting oxides, plasmonic nanoparticles (essentially Au) and quantum dots. In these cases, a physical chemistry approach and standard recipes allow a good control of the size and shape of the resulting nano-objects. However, organometallic precursors have emerged as an important class allowing the preparation of a large variety of nano-objects, concerning a large number of elements and displaying a clean and controllable surface and therefore good physical and chemical properties. This perspective article is mostly devoted to the research efforts carried out by our group on the search for new classes of precursors and on the importance of knowing their exact structure and the molecular chemistry involved prior to the fabrication of the nano-objects. PMID:23736153

  7. Atomic scale simulation of carbon nanotube nucleation from hydrocarbon precursors.

    PubMed

    Khalilov, Umedjon; Bogaerts, Annemie; Neyts, Erik C

    2015-12-22

    Atomic scale simulations of the nucleation and growth of carbon nanotubes is essential for understanding their growth mechanism. In spite of over twenty years of simulation efforts in this area, limited progress has so far been made on addressing the role of the hydrocarbon growth precursor. Here we report on atomic scale simulations of cap nucleation of single-walled carbon nanotubes from hydrocarbon precursors. The presented mechanism emphasizes the important role of hydrogen in the nucleation process, and is discussed in relation to previously presented mechanisms. In particular, the role of hydrogen in the appearance of unstable carbon structures during in situ experimental observations as well as the initial stage of multi-walled carbon nanotube growth is discussed. The results are in good agreement with available experimental and quantum-mechanical results, and provide a basic understanding of the incubation and nucleation stages of hydrocarbon-based CNT growth at the atomic level.

  8. Percolation-based precursors of transitions in extended systems

    PubMed Central

    Rodríguez-Méndez, Víctor; Eguíluz M, Víctor M.; Hernández-García, Emilio; Ramasco, José J.

    2016-01-01

    Abrupt transitions are ubiquitous in the dynamics of complex systems. Finding precursors, i.e. early indicators of their arrival, is fundamental in many areas of science ranging from electrical engineering to climate. However, obtaining warnings of an approaching transition well in advance remains an elusive task. Here we show that a functional network, constructed from spatial correlations of the system’s time series, experiences a percolation transition way before the actual system reaches a bifurcation point due to the collective phenomena leading to the global change. Concepts from percolation theory are then used to introduce early warning precursors that anticipate the system’s tipping point. We illustrate the generality and versatility of our percolation-based framework with model systems experiencing different types of bifurcations and with Sea Surface Temperature time series associated to El Niño phenomenon. PMID:27412567

  9. Compatibility of Payload Equipment for Monitoring of the Seismoionospheric Precursors.*

    NASA Astrophysics Data System (ADS)

    Ruzhin, Yu. Ya.; Depueva, A. Kh.; Stefan, V.

    1996-11-01

    The earthquake prediction including precursors appearance and their detection on the Earth's surface and at ionospheric altitudes is a matter of high interest.^2 Present warning systems are based on ground-based monitoring data. Satellite monitoring represents, due to some well known advantages (global scale, continuous records, etc.) a significant progress in the area. It is shown that by means of one payload it is possible to monitor all main parameters of seismoionospheric precursors. The active methods and airglow imager are used for detection of anomalous plasma structure during a few days before first shock. Supported in part by Tesla Labs, Inc., La Jolla, CA 92038-2946. ^1Also with Tesla Labs, Inc., La Jolla, CA 92038-2946. ^2V. Stefan (Editor-in-Chief). Environmental Physics. Frontiers in Interdisciplinary Physics series of the La Jolla International School of Physics, The Institute for Advanced Physics Studies, La Jolla, CA (IAPS Press, La Jolla, 1996).

  10. Atomic scale simulation of carbon nanotube nucleation from hydrocarbon precursors

    PubMed Central

    Khalilov, Umedjon; Bogaerts, Annemie; Neyts, Erik C.

    2015-01-01

    Atomic scale simulations of the nucleation and growth of carbon nanotubes is essential for understanding their growth mechanism. In spite of over twenty years of simulation efforts in this area, limited progress has so far been made on addressing the role of the hydrocarbon growth precursor. Here we report on atomic scale simulations of cap nucleation of single-walled carbon nanotubes from hydrocarbon precursors. The presented mechanism emphasizes the important role of hydrogen in the nucleation process, and is discussed in relation to previously presented mechanisms. In particular, the role of hydrogen in the appearance of unstable carbon structures during in situ experimental observations as well as the initial stage of multi-walled carbon nanotube growth is discussed. The results are in good agreement with available experimental and quantum-mechanical results, and provide a basic understanding of the incubation and nucleation stages of hydrocarbon-based CNT growth at the atomic level. PMID:26691537

  11. [Non-serrated precursor lesions of colorectal tumours].

    PubMed

    Langner, C

    2011-11-01

    Non-serrated precursor lesions of colorectal tumours include conventional adenomas (tubular, tubulovillous and villous), inflammatory bowel disease-associated dysplasia (intraepithelial neoplasia), and hamartoma-associated dysplasia. This short review summarizes the current literature on the adenoma-carcinoma sequence, focusing on colonic stem cells and functional crypt organization, patterns of stem cell division, niche succession and clonal conversion in the formation of a monocryptal adenoma. The process of clonal interaction between neighboring crypts as well as the development of large monoclonal adenomas from small polyclonal precursor lesions is discussed in detail. Finally, the molecular pathogenesis as well as the clinical significance of inflammatory bowel disease- and hamartoma-associated carcinogenesis is addressed.

  12. Percolation-based precursors of transitions in extended systems.

    PubMed

    Rodríguez-Méndez, Víctor; Eguíluz M, Víctor M; Hernández-García, Emilio; Ramasco, José J

    2016-01-01

    Abrupt transitions are ubiquitous in the dynamics of complex systems. Finding precursors, i.e. early indicators of their arrival, is fundamental in many areas of science ranging from electrical engineering to climate. However, obtaining warnings of an approaching transition well in advance remains an elusive task. Here we show that a functional network, constructed from spatial correlations of the system's time series, experiences a percolation transition way before the actual system reaches a bifurcation point due to the collective phenomena leading to the global change. Concepts from percolation theory are then used to introduce early warning precursors that anticipate the system's tipping point. We illustrate the generality and versatility of our percolation-based framework with model systems experiencing different types of bifurcations and with Sea Surface Temperature time series associated to El Niño phenomenon. PMID:27412567

  13. Intraspinal transplantation of mouse and human neural precursor cells

    PubMed Central

    Weinger, Jason G.; Chen, Lu; Coleman, Ronald; Leang, Ronika; Plaisted, Warren C.; Loring, Jeanne F.; Lane, Thomas E.

    2013-01-01

    This unit describes the preparation and transplantation of human neural precursor cells (hNPCs) and mouse neural precursor cells (mNPCs) into the thoracic region of the mouse spinal cord. The techniques in this unit also describe how to prepare the mouse for surgery by performing a laminectomy to expose the spinal cord for transplantation. Here we show NPCs genetically labeled with eGFP transplanted into the spinal cord of a mouse following viralmediated demyelination can efficiently be detected via eGFP expression. Transplantation of these cells into the spinal cord is an efficacious way to determine their effects in neurological disorders such as multiple sclerosis, Alzheimer's disease, and spinal cord injury. PMID:24510791

  14. COS in the stratosphere. [sulfuric acid aerosol precursor

    NASA Technical Reports Server (NTRS)

    Inn, E. C. Y.; Vedder, J. F.; Tyson, B. J.; Ohara, D.

    1979-01-01

    Carbonyl sulfide (COS) has been detected in the stratosphere, and mixing ratio measurements are reported for altitudes of 15.2 to 31.2 km. A large volume, cryogenic sampling system mounted on board a U-2 aircraft has been used for lower stratosphere measurements and a balloon platform for measurement at 31.2 km. These observations and measurements strongly support the concept that stratospheric COS is an important precursor in the formation of sulfuric acid aerosols.

  15. Viral Repression of Fungal Pheromone Precursor Gene Expression

    PubMed Central

    Zhang, Lei; Baasiri, Rudeina A.; Van Alfen, Neal K.

    1998-01-01

    Biological control of chestnut blight caused by the filamentous ascomycete Cryphonectria parasitica can be achieved with a virus that infects this fungus. This hypovirus causes a perturbation of fungal development that results in low virulence (hypovirulence), poor asexual sporulation, and female infertility without affecting fungal growth in culture. At the molecular level, the virus is known to affect the transcription of a number of fungal genes. Two of these genes, Vir1 and Vir2, produce abundant transcripts in noninfected strains of the fungus, but the transcripts are not detectable in virus-infected strains. We report here that these two genes encode the pheromone precursors of the Mat-2 mating type of the fungus; consequently, these genes have been renamed Mf2/1 and Mf2/2. To determine if the virus affects the mating systems of both mating types of this fungus, the pheromone precursor gene, Mf1/1, of a Mat-1 strain was cloned and likewise was found to be repressed in virus-infected strains. The suppression of transcription of the pheromone precursor genes of this fungus could be the cause of the mating defect of infected strains of the fungus. Although published reports suggest that a Gαi subunit may be involved in this regulation, our results do not support this hypothesis. The prepropheromone encoded by Mf1/1 is structurally similar to that of the prepro-p-factor of Schizosaccharomyces pombe. This is the first description of the complete set of pheromone precursor genes encoded by a filamentous ascomycete. PMID:9447992

  16. Single-walled hollow nanospheres assembled from the aluminogermanate precursors.

    PubMed

    Bac, Bui Hoang; Song, Yungoo; Kim, Myung Hun; Lee, Young-Boo; Kang, Il Mo

    2009-10-14

    Ordered single-walled hollow aluminogermanate (ALGE) nanospheres (NSs) with average monodisperse diameters of 5 nm have been synthesized for the first time using simple pH control. This involved basification of the ALGE precursors (having an Al/Ge ratio of 1.33) to a pH value of 13, followed by immediate acidification to a pH value of 9.

  17. Characterizing the signature of flame flashback precursor through recurrence analysis

    NASA Astrophysics Data System (ADS)

    Christodoulou, Loizos; Kabiraj, Lipika; Saurabh, Aditya; Karimi, Nader

    2016-01-01

    In this paper, it is shown that prior to flashback, small dynamical changes appear in the system. These changes appear as a drift in the recurrence plots and are found to be associated with a gradual increase in the determinism and recurrence rate. Thus, this study indicates that precursors to flame flashback exist and can be detected in the multidimensional phase space reconstructed from pressure measurements acquired during flashback. This observation could have broad academic as well as industrial implications.

  18. Boron/Carbon/Silicon/Nitrogen Ceramics And Precursors

    NASA Technical Reports Server (NTRS)

    Riccitiello, Salvatore; Hsu, Ming TA; Chen, Timothy S.

    1996-01-01

    Ceramics containing various amounts of boron, carbon, silicon, and nitrogen made from variety of polymeric precursors. Synthesized in high yield from readily available and relatively inexpensive starting materials. Stable at room temperature; when polymerized, converted to ceramics in high yield. Ceramics resist oxidation and other forms of degradation at high temperatures; used in bulk to form objects or to infiltrate other ceramics to obtain composites having greater resistance to oxidation and high temperatures.

  19. Synthesis of aromatic (13)C/(2)H-α-ketoacid precursors to be used in selective phenylalanine and tyrosine protein labelling.

    PubMed

    Lichtenecker, R J

    2014-10-14

    Recent progress in protein NMR spectroscopy revealed aromatic residues to be valuable information sources for performing structure and motion analysis of high molecular weight proteins. However, the applied NMR experiments require tailored isotope labelling patterns in order to regulate spin-relaxation pathways and optimize magnetization transfer. We introduced a methodology to use α-ketoacids as metabolic amino acid precursors in cell-based overexpression of phenylalanine and/or tyrosine labelled proteins in a recent publication, which we have now developed further by providing synthetic routes to access the corresponding side-chain labelled precursors. The target compounds allow for selective introduction of (13)C-(1)H spin systems in a highly deuterated chemical environment and feature alternating (12)C-(13)C-(12)C ring-patterns. The resulting isotope distribution is especially suited to render straightforward (13)C spin relaxation experiments possible, which provide insight into the dynamic properties of the corresponding labelled proteins.

  20. The cleavage specificity of the aspartic protease of cocoa beans involved in the generation of the cocoa-specific aroma precursors.

    PubMed

    Janek, Katharina; Niewienda, Agathe; Wöstemeyer, Johannes; Voigt, Jürgen

    2016-11-15

    Particular peptides generated from the vicilin-class(7S) globulin of the cocoa beans by acid-induced proteolysis during cocoa fermentation are essential precursors of the cocoa-specific aroma notes. As revealed by in vitro studies, the formation of the cocoa-specific aroma precursors depends on the particular cleavage specificity of the cocoa aspartic protease, which cannot be substituted by pepsin. Therefore, we have investigated the effects of aspartic protease inhibitors on both enzymes and comparatively studied their cleavage specificities using different protein substrates and MALDI-TOF mass spectrometric analyses of the generated oligopeptides. Three classes of cleavage sites have been identified and characterized: (I) sequences exclusively cleaved by the cocoa enzyme, (II) sequences cleaved by both pepsin and the cocoa enzyme, and (III) those cleaved exclusively by pepsin. In contrast to most aspartic proteases from other origins, basic amino acid residues, particularly lysine, were found to be abundant in the specific cleavage sites of the cocoa enzyme.

  1. Observations of Electromagnetic Whistler Precursors at Supercritical Interplanetary Shocks

    NASA Technical Reports Server (NTRS)

    Wilson, L. B., III; Koval, A.; Szabo, Adam; Breneman, A.; Cattell, C. A.; Goetz, K.; Kellogg, P. J.; Kersten, K.; Kasper, J. C.; Maruca, B. A.; Pulupa, M.

    2012-01-01

    We present observations of electromagnetic precursor waves, identified as whistler mode waves, at supercritical interplanetary shocks using the Wind search coil magnetometer. The precursors propagate obliquely with respect to the local magnetic field, shock normal vector, solar wind velocity, and they are not phase standing structures. All are right-hand polarized with respect to the magnetic field (spacecraft frame), and all but one are right-hand polarized with respect to the shock normal vector in the normal incidence frame. They have rest frame frequencies f(sub ci) < f much < f(sub ce) and wave numbers 0.02 approx < k rho (sub ce) approx <. 5.0. Particle distributions show signatures of specularly reflected gyrating ions, which may be a source of free energy for the observed modes. In one event, we simultaneously observe perpendicular ion heating and parallel electron acceleration, consistent with wave heating/acceleration due to these waves. Al though the precursors can have delta B/B(sub o) as large as 2, fluxgate magnetometer measurements show relatively laminar shock transitions in three of the four events.

  2. Precursor transformation method for damage detection in structures

    NASA Astrophysics Data System (ADS)

    Mehrabi, Armin B.; Tabatabai, Habib; Lotfi, Hamid R.

    1998-06-01

    In this paper, a new concept for damage detection and long- term health monitoring of structures is presented. The Precursor Transformation Method (PTM) is based on determining the causes (precursors) of change in the measured state of the structure under non-variable loading conditions (e.g. dead loads in bridges). The PTM concept addresses the inability of the current structural monitoring methods to discriminate, in structural behavior terms, the meaning of voluminous measured sensor data on a timely and cost effective basis. This method offers advantages in sensitivity and cost efficiency when compared to conventional vibration-based or parameter estimation methods. PTM was developed as part of a research project sponsored by the Federal Highway Administration on bridge stay cable condition assessment. Measured changes in the state of a structure (displacements, strains, internal forces) can be related to precursors through a transformation matrix. This matrix is formed by determining the patterns of change in the state of structure associated with externally imposed strains (temperatures) or displacements representing possible damage scenarios. A finite element model of the undamaged structure is used to calculate these patterns. The use of an undamaged model of the structure in determining damage patterns simplifies the calculation process significantly, while introducing some approximation in results. Theoretical derivations and special case studies indicate that these approximations are limited to second order effects, and in many cases well within measurement and calculation accuracies. Examples using simulated damages on two truss structures and a cable-stayed bridge are also presented.

  3. Nanoparticle colloids as spray deposition precursors to CIGS photovoltaic materials

    NASA Astrophysics Data System (ADS)

    Schulz, Douglas L.; Curtis, Calvin J.; Flitton, Rebecca A.; Wiesner, Holm; Keane, James; Matson, Richard J.; Parilla, Philip A.; Noufi, Rommel; Ginley, David S.

    1997-02-01

    Cu-In-Ga-Se nanoparticle colloids have been used as precursors in the spray deposition of photovoltaic films. Precursor colloid was prepared by reaction of the metal iodides in pyridine with sodium selenide in methanol at reduced temperature according to one of two routes: synthesis of each of the component binary selenides (Type I) followed by physical mixing of the isolated particles; or a one-pot synthesis with all the metal iodides reacting together in one flask to form a mixed-metal Cu-In-Ga-Se colloid (Type II). The constituent nanoparticles in these colloids were analyzed by TEM and XRD and were determined to be amorphous as-synthesized. Crystalline phase formation of these nanoparticles was observed by XRD after a thermal treatment. These precursor colloids were sprayed onto Mo-coated glass substrates at elevated temperatures. The nanoparticle-derived Cu-In-Ga-Se films were characterized by SEM and XRD prior to being finished into CIGS solar cell devices according to standard NREL protocol. I-V characterization of these CIGS solar cells showed these devices are limited by a large series resistance.

  4. Enhancement of polycarbonate membrane permeability due to plasma polymerization precursors

    NASA Astrophysics Data System (ADS)

    Çökeliler, Dilek

    2013-03-01

    The diffusivity of different species through a membrane depends on several factors to illustrate the structure of the matrix, molecular size and concentration of the species and temperature. This study concerns the use of the low-pressure plasma process with different monomers to confer surface chemical character to polycarbonate membranes without altering their bulk properties for change membrane permeability. Track-etched polycarbonate membranes with 0.03 μm pore sizes were modified by plasma polymerization technique with two precursors; acrylic acid and allylamine in radio frequency discharge at certain plasma process conditions (discharge power: 20 W, exposure time: 10 min, frequency: 13.56 MHz). The transport properties of model organic acid (citric acid) was studied through unmodified and modified polycarbonate membranes by using diffusion cell system. Such plasma treated membranes were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and surface energy changes were studied by static contact angle measurements. These results showed that the change of surface properties could be used to improve the transport properties of the target substrates. The diffusion of citric acid through plasma treated polycarbonate membrane was increased about 54.1 ± 3.5% with precursor: allylamine while it was decreased 48.7 ± 2.5% with precursor acrylic acid. It was observed that the presences of proper functional group (like amino) in surfaces of pores can raise the affinity to citric acid and improve its transport rate.

  5. Control of thin film processing behavior through precursor structural modifications

    SciTech Connect

    Schwartz, R.W.; Voigt, J.A.; Boyle, T.J.; Christenson, T.A.; Buchheit, C.D.

    1995-02-01

    In the sol-gel processing of ceramic thin films it has been frequently noted that the processing behavior, microstructure and properties of the films are dependent on the nature of the coating solution. In an attempt to understand such thin film processing-property relationships, the authors have systematically investigated the effects of varying the precursor nature on thin film densification and crystallization for ZrO{sub 2} and TiO{sub 2} films. Metal alkoxide starting compounds, e.g., zirconium n-butoxide{center_dot}n-butanol and titanium i-propoxide, were reacted with acetic acid and 2,4-pentanedione to prepare coating solutions for thin film deposition. The use of these chelating ligands resulted in solution oligomeric species of different nature. Studies of thin film processing indicated that film processing characteristics, i.e., consolidation, densification and crystallization, were strongly dependent on solution precursor nature. Ligand steric size, pyrolysis behavior, extent of chelation, and precursor reactivity were found to be key variables in controlling film processing characteristics.

  6. Deposition of polyimide precursor by resonant infrared laser ablation

    NASA Astrophysics Data System (ADS)

    Dygert, N. L.; Gies, A. P.; Schriver, K. E.; Haglund, R. F., Jr.

    2007-11-01

    We report the successful deposition of a polyimide precursor using resonant infrared laser ablation (RIR-LA). A solution of poly(amic acid) (PAA) dissolved in N-methyl-2-pyrrolidinone (NMP), the melt processable precursor to polyimide, was frozen in liquid nitrogen for use as an ablation target in a high-vacuum chamber. Fourier transform infrared spectroscopy was used to determine that the local chemical structure remained unaltered. Gel permeation chromatography demonstrated that the transferred PAA retained its molecular weight, showing that RIR-LA is able to transfer the polymer intact, with no detectable chain fragmentation. These results are in stark contrast to UV-processing which degrades the polymer. After deposition the PAA may be removed with a suitable solvent; however, once the material has undergone cyclodehydration it forms an impenetrable three-dimensional network associated with thermosetting polymers. The transfer of uncured PAA precursor supports the hypothesis that RIR-LA is intrinsically a low temperature process, because the PAA is transferred without reaching the curing temperature. The RIR-LA also effectively removes the solvent NMP from the PAA, during both the ablation and deposition phases; this is a necessary step in generating PI films.

  7. LWIR hyperspectral imaging application and detection of chemical precursors

    NASA Astrophysics Data System (ADS)

    Lavoie, Hugo; Thériault, Jean-Marc; Bouffard, François; Puckrin, Eldon; Dubé, Denis

    2012-10-01

    Detection and identification of Toxic industrial chemicals (TICs) represent a major challenge to protect and sustain first responder and public security. In this context, passive Hyperspectral Imaging (HSI) is a promising technology for the standoff detection and identification of chemical vapors emanating from a distant location. To investigate this method, the Department of National Defense and Public Safety Canada have mandated Defense Research and Development Canada (DRDC) - Valcartier to develop and test Very Long Wave Infrared (VLWIR) HSI sensors for standoff detection. The initial effort was focused to address the standoff detection and identification of toxic industrial chemicals (TICs), surrogates and precursors. Sensors such as the Improved Compact ATmospheric Sounding Interferometer (iCATSI) and the Multi-option Differential Detection and Imaging Fourier Spectrometer (MoDDIFS) were developed for this application. This paper presents the sensor developments and preliminary results of standoff detection and identification of TICs and precursors. The iCATSI and MoDDIFS sensors are based on the optical differential Fourier-transform infrared (FTIR) radiometric technology and are able to detect, spectrally resolve and identify small leak at ranges in excess of 1 km. Results from a series of trials in asymmetric threat type scenarios are reported. These results serve to establish the potential of passive standoff HSI detection of TICs, precursors and surrogates.

  8. The glucagon superfamily: precursor structure and gene organization.

    PubMed

    Bell, G I

    1986-01-01

    The glucagon superfamily includes the polypeptides glucagon, secretin, vasoactive inhibitory peptide (VIP), gastric inhibitory peptide and growth hormone-releasing factor (GHRF). Complementary DNA clones which encode the precursors to glucagon, VIP and GHRF have been isolated. Although the sizes and sequences of preproglucagon, prepro VIP and preproGHRF are distinct, the structural organization of the three precursors is similar. Each has a signal peptide, an NH2-terminal peptide and one, two or three peptides whose sequences are related to glucagon. Prepro VIP and preproGHRF also have a COOH-terminal peptide. The sequences of two different anglerfish preproglucagon molecules have been determined and they contain the sequences of glucagon and a related peptide. In contrast, hamster, cow and rat preproglucagon contain the sequences of glucagon and two related peptides. Human and rat prepro VIP contain the sequences of VIP and the related peptide PHM/PHI-27. Human and rat preproGHRF contain the sequence of only one peptide related to glucagon, i.e., GHRF. The genes for both preproglucagon and preproGHRF have been isolated. Their exon-intron organization indicates that each exon encodes a functionally distinct region of the precursor and mRNA. PMID:3092195

  9. Structural analysis of the precursor pseudogap in cuprate superconductors

    NASA Astrophysics Data System (ADS)

    Suzuki, Sokichi

    2016-10-01

    We investigate the precursor pseudogap (PP) state that emerges on the lower temperature side of the pseudogap phase in cuprate superconductors based on the characteristic layer structure. The coherence among layers in the electronic state may be broken by low energy thermal interactions, whereas the coherence within the layers remains in the phase above the superconducting (SC) phase on account of strongness of the bonding. In this state, the two-electron energy gain (TEG) is also larger than that of SC state and the one-electron energy gain (OEG) is smaller than that of the SC state. We call this incoherent ensemble of in-layer states the in-layer electronic state system (IESS). The PP state is a crossover state between IESS and the normal pseudogap (NP) state, which appears on the upper temperature side, because the d-wave pairing symmetry in cuprates inverts the sign of the difference of the total electronic energy gain between the IESS and the NP state around the nodal region, even though it is positive overall. We perform our analysis at the mean field level. We show that the relationships among the SC gap, the gap of in-layer state, and the transition temperatures in the relevant phases are compatible with existing experimental data. The proposed precursor state requires pairing models to make the SC interactions three-dimensional beyond a single layer, although the precursors have in-layer properties.

  10. Oxidation and formation of deposit precursors in hydrocarbon fuels

    NASA Technical Reports Server (NTRS)

    Mayo, F. R.; Lan, B.; Cotts, D. B.; Buttrill, S. E., Jr.; St.john, G. A.

    1983-01-01

    The oxidation of two jet turbine fuels and some pure hydrocarbons was studied at 130 C with and without the presence of small amounts of N-methyl pyrrole (NMP) or indene. Tendency to form solid-deposit precursors was studied by measuring soluble gum formation as well as dimer and trimer formation using field ionization mass spectrometry. Pure n-dodecane oxidized fastest and gave the smallest amount of procursors. An unstable fuel oil oxidized much slower but formed large amounts of precursors. Stable Jet A fuel oxidized slowest and gave little precursors. Indene either retarded or accelerated the oxidation of n-dodecane, depending on its concentration, but always caused more gum formation. The NMP greatly retarded n-dodecane oxidation but accelerated Jet A oxidation and greatly increased the latter's gum formation. In general, the additive reacted faster and formed most of the gum. Results are interpreted in terms of classical cooxidation theory. The effect of oxygen pressure on gum formation is also reported.

  11. Development of techniques for tagging precursor and essential chemicals

    SciTech Connect

    Swansiger, W.A.; Shepodd, T.J.; Phillips, M.L.F.

    1994-01-01

    The ability to identify the manufacturers and distributors of chemicals seized in raids of illicit drug labs would be of great value in controlling the diversion of these chemicals. We developed a tagging scheme based on the addition of sub-ppM concentrations of various combinations of rare-earth elements to the target chemicals and evaluated a number of techniques for detecting the tags. We developed soluble tags for tagging liquids and selected Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) as the preferred detection technique. We developed insoluble tags for tagging solids and developed methods to analyze them and mix them into solid precursors. We have successfully demonstrated the tagging of several solvents and two of the precursor chemicals used in one of the most popular clandestine methamphetamine syntheses (ephedrine reacting with hydriodic acid/red phosphorus). The tagging scheme is capable of yielding tens of thousands of signatures (using holmium as an internal standard and up to 9 rare-earths at up to 3 concentrations yields 3{sup 9} {minus} 1 = 19,682 signatures) and is applicable to most of the chemicals on the precursor and essential chemicals list. In the concentrations employed, the tags are safe enough to be added to pharmaceuticals and cheap enough to tag tanker loads of chemicals.

  12. Serrated and non-serrated precursor lesions of colorectal cancer.

    PubMed

    Langner, Cord

    2015-01-01

    Although often viewed as a single disease, colorectal cancer more accurately represents a family of diseases with different precursor lesions. Conventional (tubular, tubulovillous and villous) adenomas are the most common neoplastic lesions occurring in the large intestine. They have adenomatous polyposis coli (APC) mutations and arise from dysplastic aberrant crypt foci, initially as polyclonal lesions. In sporadic tumours, neoplastic progression follows the traditional pathway (chromosomal instability pathway), resulting in CpG island methylator phenotype (CIMP)-negative, microsatellite-stable (MSS), BRAF and KRAS wild-type cancers. Germline mutations in the APC gene lead to familial adenomatous polyposis. Conventional adenomas are also the precursors of Lynch syndrome-associated microsatellite-instable (MSI-high) cancers. Sessile serrated adenoma/polyp (SSA/P) is the principal precursor lesion of the serrated pathway, in which BRAF mutation can lead to colorectal cancer with MSI-high CIMP-high or MSS CIMP-high phenotype. SSA/Ps have been associated with synchronous and metachronous invasive adenocarcinomas as well as so-called interval carcinomas. Serrated polyposis is rare but most likely underdiagnosed. Affected individuals bear an increased but unspecified risk for the development of colorectal cancer; close endoscopic surveillance is warranted. Traditional serrated adenomas (TSAs) are much less common than the other serrated lesions. Cancers originating from TSAs may show KRAS mutation with a CIMP-high MSS phenotype.

  13. Improved removals of trihalomethane precursors by small water supply systems

    SciTech Connect

    Collins, M.R.; Eighmy, T.T.; Fenstermacher, J.M.; Spanos, S.K.; Spencer, C.M. )

    1989-06-01

    Selected slow sand filter modifications that could enhance the principal removal mechanisms of biodegradation and adsorption and would not compromise the simplicity of the treatment process were explored in research conducted at the University of New Hampshire. The modifications were evaluated for their potential to improve removal of trihalomethanes (THM) precursor material and particulate matter over conventionally operated slow sand filters. The results suggest that those water utilities that are considering slow sand filtration and want to improve THM precursor removals construct filter units that provide the following capabilities: increase biodegradation potential by increasing bacterial populations with filter depth through incorporating a cleaning procedure that harrows the filter media; or increase adsorption removals by adding granular activated carbon or anionic resin as a filter media amendment. THM precursor removals by slow sand filters may be independent of organic loading rate suggesting that smaller filter units operating at high filtration rates may be used to offset construction costs. However, the savings in construction costs may be lost if an efficient filter cleaning procedure is not correspondingly implemented since increased removal rates will increase headloss development. 24 refs., 7 figs., 1 tab.

  14. Phylogenetic appearance of Neuropeptide S precursor proteins in tetrapods

    PubMed Central

    Reinscheid, Rainer K.

    2007-01-01

    Sleep and emotional behavior are two hallmarks of vertebrate animal behavior, implying that specialized neuronal circuits and dedicated neurochemical messengers may have been developed during evolution to regulate such complex behaviors. Neuropeptide S (NPS) is a newly identified peptide transmitter that activates a typical G protein-coupled receptor. Central administration of NPS produces profound arousal, enhances wakefulness and suppresses all stages of sleep. In addition, NPS can alleviate behavioral responses to stress by producing anxiolytic-like effects. A bioinformatic analysis of current genome databases revealed that the NPS peptide precursor gene is present in all vertebrates with the exception of fish. A high level of sequence conservation, especially of aminoterminal structures was detected, indicating stringent requirements for agonist-induced receptor activation. Duplication of the NPS precursor gene was only found in one out of two marsupial species with sufficient genome coverage (Monodelphis domestica; opossum), indicating that the duplicated opossum NPS sequence might have arisen as an isolated event. Pharmacological analysis of both Monodelphis NPS peptides revealed that only the closely related NPS peptide retained agonistic activity at NPS receptors. The duplicated precursor might be either a pseudogene or could have evolved different receptor selectivity. Together, these data show that NPS is a relatively recent gene in vertebrate evolution whose appearance might coincide with its specialized physiological functions in terrestrial vertebrates. PMID:17293003

  15. Precursors in the preparation of transition metal nitrides and transition metal carbonitrides and their reaction intermediates

    DOEpatents

    Maya, Leon

    1991-01-01

    A process for making ammonolytic precursors to nitride and carbonitride ceramics. Extreme reaction conditions are not required and the precursor is a powder-like substance that produces ceramics of improved purity and morphology upon pyrolysis.

  16. Precursor Analysis for Flight- and Ground-Based Anomaly Risk Significance Determination

    NASA Technical Reports Server (NTRS)

    Groen, Frank

    2010-01-01

    This slide presentation reviews the precursor analysis for flight and ground based anomaly risk significance. It includes information on accident precursor analysis, real models vs. models, and probabilistic analysis.

  17. Progressing from identification and functional analysis of precursor behavior to treatment of self-injurious behavior.

    PubMed

    Dracobly, Joseph D; Smith, Richard G

    2012-01-01

    This multiple-study experiment evaluated the utility of assessing and treating severe self-injurious behavior SIB based on the outcomes of a functional analysis of precursor behavior. In Study 1, a precursor to SIB was identified using descriptive assessment and conditional probability analyses. In Study 2, a functional analysis of precursor behavior was conducted. Finally, study 3 evaluated the effects of a treatment in which precursor behavior produced the maintaining variable identified in the precursor functional analysis. Studies 1 and 3 were conducted in two settings in the participants natural environment, where data collection was ongoing throughout the course of the study. Results showed that it was possible to identify a precursor to infrequent but severe SIB, that a functional analysis of precursor behavior suggested a clear operant function, and that treatment based on the results of the precursor functional analysis reduced SIB in the natural environment.

  18. PROGRESSING FROM IDENTIFICATION AND FUNCTIONAL ANALYSIS OF PRECURSOR BEHAVIOR TO TREATMENT OF SELFINJURIOUS BEHAVIOR

    PubMed Central

    Dracobly, Joseph D; Smith, Richard G

    2012-01-01

    This multiplestudy experiment evaluated the utility of assessing and treating severe selfinjurious behavior SIB based on the outcomes of a functional analysis of precursor behavior. In Study 1, a precursor to SIB was identified using descriptive assessment and conditional probability analyses. In Study 2, a functional analysis of precursor behavior was conducted. Finally, Study 3 evaluated the effects of a treatment in which precursor behavior produced the maintaining variable identified in the precursor functional analysis. Studies 1 and 3 were conducted in two settings in the participants natural environment, where data collection was ongoing throughout the course of the study. Results showed that it was possible to identify a precursor to infrequent but severe SIB, that a functional analysis of precursor behavior suggested a clear operant function, and that treatment based on the results of the precursor functional analysis reduced SIB in the natural environment. PMID:22844142

  19. Silencing of Amyloid Precursor Protein Expression Using a New Engineered Delta Ribozyme

    PubMed Central

    Ben Aissa, Manel; April, Marie-Claude; Bergeron, Lucien-Junior; Perreault, Jean-Pierre; Levesque, Georges

    2012-01-01

    Alzheimer's disease (AD) etiological studies suggest that an elevation in amyloid-β peptides (Aβ) level contributes to aggregations of the peptide and subsequent development of the disease. The major constituent of these amyloid peptides is the 1 to 40–42 residue peptide (Aβ40−42) derived from amyloid protein precursor (APP). Most likely, reducing Aβ levels in the brain may block both its aggregation and neurotoxicity and would be beneficial for patients with AD. Among the several possible ways to lower Aβ accumulation in the cells, we have selectively chosen to target the primary step in the Aβ cascade, namely, to reduce APP gene expression. Toward this end, we engineered specific SOFA-HDV ribozymes, a new generation of catalytic RNA tools, to decrease APP mRNA levels. Additionally, we demonstrated that APP-ribozymes are effective at decreasing APP mRNA and protein levels as well as Aβ levels in neuronal cells. Our results could lay the groundwork for a new protective treatment for AD. PMID:22482079

  20. Investigation of pyridine carboxylic acids in CM2 carbonaceous chondrites: Potential precursor molecules for ancient coenzymes

    NASA Astrophysics Data System (ADS)

    Smith, Karen E.; Callahan, Michael P.; Gerakines, Perry A.; Dworkin, Jason P.; House, Christopher H.

    2014-07-01

    The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We also report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

  1. Preparation of silicon carbide from organosilicon gels: I. Synthesis and characterization of precursor gels

    SciTech Connect

    White, D.A.; Oleff, S.M.; Boyer, R.D.; Budinger, P.A.; Fox, J.R. )

    1987-01-01

    Polymeric organosilicon gel precursors to SiC have been prepared using trifunctional chloro and alkoxysilanes that contain both the Si and C necessary for SiC formation. Crosslinked gels having the ideal formula (RSiO{sub 1.5}){sub n} have been synthesized by a hydrolysis/condensation scheme for a series of saturated and unsaturated R groups. The starting gels have been characterized by elemental analysis and by a variety of spectroscopic and physical measurements including Fourier transform infrared spectroscopy, XRD, surface-area and pore-volume determination, and thermal gravimetric analysis. {sup 13}C and {sup 29}Si solid-state NMR analysis proved to be particularly powerful for characterizing these gels by showing the degree of crosslinking and the residual hydroxy/alkoxy content. Under an inert atmosphere, the gels decompose to produce an intimate mixture of C and SiO{sub 2} which can react to form SiC at higher temperatures. The pyrolysis of these gels to produce SiC is described in Part II.

  2. Enhanced cathode performance of nano-sized lithium iron phosphate composite using polytetrafluoroethylene as carbon precursor

    NASA Astrophysics Data System (ADS)

    Avci, Ercan

    2014-12-01

    Herein we report a facile and efficient solid state synthesis of carbon coated lithium iron phosphate (LiFePO4/C) cathode material achieved through the pyrolysis of polytetrafluoroethylene (PTFE). The current investigation is comparatively analyzed with the results of the composites of LiFePO4/C (LFP/C) synthesized using polystyrene-block-polybutadiene (PS-b-PBD), polyethyhylene (PE) and sucrose as carbon precursors. The optimized LFP/CPTFE composite is synthesized at 700 °C using 10 wt.% PTFE. The composite exhibits remarkable improvement in capacity, cyclability and rate capability compared to those of LFP/C synthesized using (PS-b-PBD), PE and sucrose. The specific discharge capacities as high as 166 mA h g-1 (theoretical capacity: 170 mA h g-1) at 0.2 C and 114 mA h g-1 at 10 C rates were achieved with LFP/CPTFE. In addition, the composite exhibits a long-term cycling stability with the capacity loss of only 11.4% after 1000 cycles. PTFE shifts the size distribution of the composite to nanometer scale (approximately 120 nm), however the addition of sucrose and other polymers do not have such an effect. According to TEM and XPS analysis, LFP/CPTFE particles are mostly coated with a few nanometers thick carbon layer forming a core-shell structure. Residual carbon does not contain fluorine.

  3. Enhanced sample multiplexing for nitrotyrosine-modified proteins using combined precursor isotopic labeling and isobaric tagging.

    PubMed

    Robinson, Renã A S; Evans, Adam R

    2012-06-01

    Current strategies for identification and quantification of 3-nitrotyrosine (3NT) post-translationally modified proteins (PTM) generally rely on biotin/avidin enrichment. Quantitative approaches have been demonstrated which employ isotopic labeling or isobaric tagging in order to quantify differences in the relative abundances of 3NT-modified proteins in two or potentially eight samples, respectively. Here, we present a novel strategy which uses combined precursor isotopic labeling and isobaric tagging (cPILOT) to increase the multiplexing capability of quantifying 3NT-modified proteins to 12 or 16 samples using commercially available tandem mass tags (TMT) or isobaric tags for relative and absolute quantification (iTRAQ), respectively. This strategy employs "light" and "heavy" labeled acetyl groups to block both N-termini and lysine residues of tryptic peptides. Next, 3NT is reduced to 3-aminotyrosine (3AT) using sodium dithionite followed by derivatization of light and heavy labeled 3AT-peptides with either TMT or iTRAQ multiplex reagents. We demonstrate the proof-of-principle utility of cPILOT with in vitro nitrated bovine serum albumin (BSA) and mouse splenic proteins using TMT(0), TMT(6), and iTRAQ(8) reagents and discuss limitations of the strategy. PMID:22509719

  4. Mutations of the precursor to the terminal protein of adenovirus serotypes 2 and 5.

    PubMed Central

    Pettit, S C; Horwitz, M S; Engler, J A

    1989-01-01

    Using a series of transient expression plasmids and adenovirus-specific DNA replication assays for both initiation and elongation, we measured the relative activities of mutant polypeptides of the precursor to the terminal protein (pTP) in vitro. Mutations that removed two to six amino acids of the amino terminus gradually decreased pTP activity; a deletion of 18 amino acids was completely inactive. Replacement of cysteine at residue 8 with a serine had little effect on pTP activity. Two amino-terminal in-frame linker insertion mutant polypeptides previously characterized in vivo as either replication defective or temperature sensitive had considerable activity at the permissive temperature in vitro. For one mutant pTP with a temperature-sensitive phenotype in vivo, elongation activity was decreased more than initiation in vitro, suggesting a role for this protein after the initiation step. Replacement mutations of serine 580, the site of covalent attachment of dCTP, completely abolished pTP function for both initiation and elongation. Images PMID:2511338

  5. Investigation of Pyridine Carboxylic Acids in CM2 Carbonaceous Chondrites: Potential Precursor Molecules for Ancient Coenzymes

    NASA Technical Reports Server (NTRS)

    Smith, Karen E.; Callahan, Michael P.; Gerakines, Perry A.; Dworkin, Jason P.; House, Christopher H.

    2014-01-01

    The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We lso report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

  6. Investigation of Pyridine Carboxylic Acids in CM2 Carbonaceous Chondrites: Potential Precursor Molecules for Ancient Coenzymes

    NASA Technical Reports Server (NTRS)

    Smith, Karen E.; Callahan, Michael P.; Gerakines, Perry A.; Dworkin, Jason P.; House, Christopher H.

    2014-01-01

    The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We also report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

  7. Cleavage of amyloid precursor protein by an archaeal presenilin homologue PSH

    PubMed Central

    Dang, Shangyu; Wu, Shenjie; Wang, Jiawei; Li, Hongbo; Huang, Min; He, Wei; Li, Yue-Ming; Wong, Catherine C. L.; Shi, Yigong

    2015-01-01

    Aberrant cleavage of amyloid precursor protein (APP) by γ-secretase contributes to the development of Alzheimer’s disease. More than 200 disease-derived mutations have been identified in presenilin (the catalytic subunit of γ-secretase), making modulation of γ-secretase activity a potentially attractive therapeutic opportunity. Unfortunately, the technical challenges in dealing with intact γ-secretase have hindered discovery of modulators and demand a convenient substitute approach. Here we report that, similar to γ-secretase, the archaeal presenilin homolog PSH faithfully processes the substrate APP C99 into Aβ42, Aβ40, and Aβ38. The molar ratio of the cleavage products Aβ42 over Aβ40 by PSH is nearly identical to that by γ-secretase. The proteolytic activity of PSH is specifically suppressed by presenilin-specific inhibitors. Known modulators of γ-secretase also modulate PSH similarly in terms of the Aβ42/Aβ40 ratio. Structural analysis reveals association of a known γ-secretase inhibitor with PSH between its two catalytic aspartate residues. These findings identify PSH as a surrogate protease for the screening of agents that may regulate the protease activity and the cleavage preference of γ-secretase. PMID:25733893

  8. Progranulin (granulin/epithelin precursor) and its constituent granulin repeats repress transcription from cellular promoters

    PubMed Central

    Hoque, Mainul; Mathews, Michael B.; Pe’ery, Tsafi

    2010-01-01

    Progranulin (also known as granulin/epithelin precursor, GEP) is composed of seven granulin/epithelin repeats (granulins) and functions both as a full-length protein and as individual granulins. It is a secretory protein but a substantial amount of GEP is found inside cells, some in complexes with positive transcription elongation factor b (P-TEFb). GEP and certain granulins interact with the cyclin T1 subunit of P-TEFb, and with its HIV-1 Tat co-factor, leading to repression of transcription from the HIV promoter. We show that GEP lacking the signal peptide (GEPspm) remains inside cells and, like wild-type GEP, interacts with cyclin T1 and Tat. GEPspm represses transcription from the HIV-1 promoter at the RNA level. Granulins that bind cyclin T1 are phosphorylated by P-TEFb in vivo and in vitro on serine residues. GEPspm and those granulins that interact with cyclin T1 also inhibit transcription from cellular cad and c-myc promoters, which are highly dependent on P-TEFb, but not from the PCNA promoter. In addition, GEPspm and granulins repress transcriptional activation by VP16 or c-Myc, proteins that bind and recruit P-TEFb to responsive promoters. These data suggest that intracellular GEP is a promoter-specific transcriptional repressor that modulates the function of cellular and viral transcription factors. PMID:20054825

  9. Adenocarcinoma of the minor duodenal papilla and its precursor lesions: a clinical and pathologic study.

    PubMed

    Shia, Jinru; Agaram, Narasimhan P; Olgac, Semra; Cobanov, Brando; Adsay, Volkan; Klimstra, David S

    2014-04-01

    The minor duodenal papilla drains the accessory pancreatic duct of Santorini and lies proximal to the ampulla of Vater. Adenocarcinoma and its precursor lesions arising in the minor papilla are rare. Literature data thus far are limited to a few individual case reports, and the condition is consequently poorly defined. Our study cases were composed of carcinomas fulfilling all of the following criteria: location at 1.5 to 2.5 cm proximal to the major papilla; presence of associated submucosal pancreatobiliary-type ducts with periductal glands or acinar tissue; a predominant submucosal location of the tumor; and lack of an intestinal-type adenoma in the adjacent duodenal mucosa. Tumors were studied morphologically, immunohistochemically, and clinically. Nine cases fulfilling the inclusion criteria were identified. There were 5 men and 4 women with an age range of 50 to 76 years (median, 72 y). The tumor size ranged from 1.2 to 4.4 cm (median, 3 cm). The carcinomas were of colloid type (3 tumors), pancreatobiliary type (4), or nonmucinous intestinal type (2). Five cases were associated with an intraductal papillary mucinous neoplasm (IPMN)-like precursor lesion within the residual structures of the minor papilla in the duodenal submucosa. Immunohistochemically, the intestinal-type and mucinous-type tumors tended to be positive for CK20, CDX2, MUC2, and B72.3, and pancreatobiliary-type tumors tended to be positive for CK7, MUC1, B72.3, and CA125. Loss of DPC4 (Smad4) expression was found in the pancreatobiliary-type carcinomas only. Two tumors showed loss of DNA mismatch-repair protein expression, one losing MLH1 and PMS2 and the other losing MSH6. Both patients were older than 60 years, and neither had germline mutation testing. Follow-up information was available for 6 patients (median follow-up time, 67.5 mo): 3 of the 6 patients died of disease at 60, 75, and 85 months after surgery, respectively, and all 3 patients had an intestinal-type carcinoma (1 colloid and

  10. Adenocarcinoma of the minor duodenal papilla and its precursor lesions: a clinical and pathologic study.

    PubMed

    Shia, Jinru; Agaram, Narasimhan P; Olgac, Semra; Cobanov, Brando; Adsay, Volkan; Klimstra, David S

    2014-04-01

    The minor duodenal papilla drains the accessory pancreatic duct of Santorini and lies proximal to the ampulla of Vater. Adenocarcinoma and its precursor lesions arising in the minor papilla are rare. Literature data thus far are limited to a few individual case reports, and the condition is consequently poorly defined. Our study cases were composed of carcinomas fulfilling all of the following criteria: location at 1.5 to 2.5 cm proximal to the major papilla; presence of associated submucosal pancreatobiliary-type ducts with periductal glands or acinar tissue; a predominant submucosal location of the tumor; and lack of an intestinal-type adenoma in the adjacent duodenal mucosa. Tumors were studied morphologically, immunohistochemically, and clinically. Nine cases fulfilling the inclusion criteria were identified. There were 5 men and 4 women with an age range of 50 to 76 years (median, 72 y). The tumor size ranged from 1.2 to 4.4 cm (median, 3 cm). The carcinomas were of colloid type (3 tumors), pancreatobiliary type (4), or nonmucinous intestinal type (2). Five cases were associated with an intraductal papillary mucinous neoplasm (IPMN)-like precursor lesion within the residual structures of the minor papilla in the duodenal submucosa. Immunohistochemically, the intestinal-type and mucinous-type tumors tended to be positive for CK20, CDX2, MUC2, and B72.3, and pancreatobiliary-type tumors tended to be positive for CK7, MUC1, B72.3, and CA125. Loss of DPC4 (Smad4) expression was found in the pancreatobiliary-type carcinomas only. Two tumors showed loss of DNA mismatch-repair protein expression, one losing MLH1 and PMS2 and the other losing MSH6. Both patients were older than 60 years, and neither had germline mutation testing. Follow-up information was available for 6 patients (median follow-up time, 67.5 mo): 3 of the 6 patients died of disease at 60, 75, and 85 months after surgery, respectively, and all 3 patients had an intestinal-type carcinoma (1 colloid and

  11. Preparation of Bi-Sr-Ca-Cu-O superconductors from oxide-glass precursors

    DOEpatents

    Hinks, David G.; Capone, II, Donald W.

    1992-01-01

    A superconductor and precursor therefor from oxide mixtures of Ca, Sr, Bi and Cu. Glass precursors quenched to elevated temperatures result in glass free of crystalline precipitates having enhanced mechanical properties. Superconductors are formed from the glass precursors by heating in the presence of oxygen to a temperature below the melting point of the glass.

  12. 40 CFR 93.164 - Inter-precursor mitigation measures and offsets.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Inter-precursor mitigation measures... § 93.164 Inter-precursor mitigation measures and offsets. Federal agencies must reduce the same type of... mitigation measures of different precursors of the same criteria pollutant, if such trades are allowed by...

  13. 40 CFR 93.164 - Inter-precursor mitigation measures and offsets.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Inter-precursor mitigation measures... § 93.164 Inter-precursor mitigation measures and offsets. Federal agencies must reduce the same type of... mitigation measures of different precursors of the same criteria pollutant, if such trades are allowed by...

  14. 40 CFR 93.164 - Inter-precursor mitigation measures and offsets.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Inter-precursor mitigation measures... § 93.164 Inter-precursor mitigation measures and offsets. Federal agencies must reduce the same type of... mitigation measures of different precursors of the same criteria pollutant, if such trades are allowed by...

  15. Liquid precursor for deposition of indium selenide and method of preparing the same

    SciTech Connect

    Curtis, Calvin J.; Miedaner, Alexander; van Hest, Marinus Franciscus Antonius Maria; Ginley, David S.; Hersh, Peter A.; Eldada, Louay; Stanbery, Billy J.

    2015-09-22

    Liquid precursors containing indium and selenium suitable for deposition on a substrate to form thin films suitable for semiconductor applications are disclosed. Methods of preparing such liquid precursors and method of depositing a liquid precursor on a substrate are also disclosed.

  16. Functional Analysis of Precursors for Serious Problem Behavior and Related Intervention

    ERIC Educational Resources Information Center

    Langdon, Nancy A.; Carr, Edward G.; Owen-DeSchryver, Jamie S.

    2008-01-01

    Precursor behaviors are innocuous behaviors that reliably precede the occurrence of problem behavior. Intervention efforts applied to precursors might prevent the occurrence of severe problem behavior. We examined the relationship between precursor behavior and problem behavior in three individuals with developmental disabilities. First, a…

  17. 40 CFR 93.164 - Inter-precursor mitigation measures and offsets.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Inter-precursor mitigation measures... § 93.164 Inter-precursor mitigation measures and offsets. Federal agencies must reduce the same type of... mitigation measures of different precursors of the same criteria pollutant, if such trades are allowed by...

  18. Nanoporous gold obtained from a metallic glass precursor used as substrate for surface-enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Scaglione, F.; Paschalidou, E. M.; Rizzi, P.; Bordiga, S.; Battezzati, L.

    2015-09-01

    Nanoporous gold (NPG) has been synthesized by electrochemical de-alloying a new precursor, amorphous Au30Cu38Ag7Pd5Si20 (at.%), starting from melt-spun ribbons. Ligaments ranging from 75 to 210 nm depending on the de-alloying time were obtained. Analytical and electrochemical evidence showed the ligaments contain residual Cu, Ag and Pd. Surface-enhanced Raman scattering from the NPG was investigated using pyridine and 4,4‧-bi-pyridine as probe molecules. It was found that the activity is at maximum when the ribbon is fully de-alloyed although the ligaments then have a larger size. The enhancement is attributed to the small size of crystals in the ligaments, to their morphology and to trapped atoms.

  19. Potential of jackfruit peel as precursor for activated carbon prepared by microwave induced NaOH activation.

    PubMed

    Foo, K Y; Hameed, B H

    2012-05-01

    The feasibility of preparing activated carbon (JPAC) from jackfruit peel, an industrial residue abundantly available from food manufacturing plants via microwave-assisted NaOH activation was explored. The influences of chemical impregnation ratio, microwave power and radiation time on the properties of activated carbon were investigated. JPAC was examined by pore structural analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption isotherm, elemental analysis, surface acidity/basicity and zeta potential measurements. The adsorptive behavior of JPAC was quantified using methylene blue as model dye compound. The best conditions resulted in JPAC with a monolayer adsorption capacity of 400.06 mg/g and carbon yield of 80.82%. The adsorption data was best fitted to the pseudo-second-order equation, while the adsorption mechanism was well described by the intraparticle diffusion model. The findings revealed the versatility of jackfruit peels as good precursor for preparation of high quality activated carbon.

  20. Highly efficient residue-selective labeling with isotope-labeled Ile, Leu, and Val using a new auxotrophic E. coli strain.

    PubMed

    Miyanoiri, Yohei; Ishida, Yojiro; Takeda, Mitsuhiro; Terauchi, Tsutomu; Inouye, Masayori; Kainosho, Masatsune

    2016-06-01

    We recently developed a practical protocol for preparing proteins bearing stereo-selectively (13)C-methyl labeled leucines and valines, instead of the commonly used (13)C-methyl labeled precursors for these amino acids, by E. coli cellular expression. Using this protocol, proteins with any combinations of isotope-labeled or unlabeled Leu and Val residues were prepared, including some that could not be prepared by the precursor methods. However, there is still room for improvement in the labeling efficiencies for Val residues, using the methods with labeled precursors or Val itself. This is due to the fact that the biosynthesis of Val could not be sufficiently suppressed, even by the addition of large amounts of Val or its precursors. In this study, we completely solved this problem by using a mutant strain derived from E. coli BL21(DE3), in which the metabolic pathways depending on two enzymes, dihydroxy acid dehydratase and β-isopropylmalate dehydrogenase, are completely aborted by deleting the ilvD and leuB genes, which respectively encode these enzymes. The ΔilvD E. coli mutant terminates the conversion from α,β-dihydroxyisovalerate to α-ketoisovalerate, and the conversion from α,β-dihydroxy-α-methylvalerate to α-keto-β-methylvalerate, which produce the preceding precursors for Val and Ile, respectively. By the further deletion of the leuB gene, the conversion from Val to Leu was also fully terminated. Taking advantage of the double-deletion mutant, ΔilvDΔleuB E. coli BL21(DE3), an efficient and residue-selective labeling method with various isotope-labeled Ile, Leu, and Val residues was established.

  1. Determination of gamma-hydroxybutyrate (GHB) and its precursors in blood and urine samples: a salting-out approach.

    PubMed

    Kankaanpää, Aino; Liukkonen, Raija; Ariniemi, Kari

    2007-08-01

    Gamma-hydroxybutyrate (GHB) is an increasingly popular drug of abuse that causes stimulation, euphoria, anxiolysis or hypnosis, depending on the dose used. Low doses of the drug are used recreationally, and also implicated in drug-facilitated sexual assaults. Because of the unusually steep dose-response curves, accidental GHB overdosing, leading to coma, seizures or death can occur. Being a controlled substance, GHB is often substituted with its non-scheduled precursors gamma-butyrolactone (GBL) and 1,4-butanediol (BD), which are rapidly metabolized into GHB in the body. Here we describe an assay for GHB, GBL and BD in blood and/or urine samples. GHB and BD were extracted from diluted 200 microL aliquots of samples with t-butylmethylether (plus internal standard benzyl alcohol) in test tubes preloaded with NaCl. After acidification and centrifugation the solvent phase was transferred to a test tube preloaded with Na(2)SO(4), incubated for 30 min, centrifuged again, and evaporated in vacuum. The residue was mixed with N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) in acetonitrile, and injected into a GC-MS. When analyzing GBL, the salting-out step was omitted, and analysis was performed with a GC-FID apparatus. As revealed by the validation data this procedure is suitable for quantitative determination of GHB and its precursors in blood and/or urine samples. PMID:17658710

  2. Determination of gamma-hydroxybutyrate (GHB) and its precursors in blood and urine samples: a salting-out approach.

    PubMed

    Kankaanpää, Aino; Liukkonen, Raija; Ariniemi, Kari

    2007-08-01

    Gamma-hydroxybutyrate (GHB) is an increasingly popular drug of abuse that causes stimulation, euphoria, anxiolysis or hypnosis, depending on the dose used. Low doses of the drug are used recreationally, and also implicated in drug-facilitated sexual assaults. Because of the unusually steep dose-response curves, accidental GHB overdosing, leading to coma, seizures or death can occur. Being a controlled substance, GHB is often substituted with its non-scheduled precursors gamma-butyrolactone (GBL) and 1,4-butanediol (BD), which are rapidly metabolized into GHB in the body. Here we describe an assay for GHB, GBL and BD in blood and/or urine samples. GHB and BD were extracted from diluted 200 microL aliquots of samples with t-butylmethylether (plus internal standard benzyl alcohol) in test tubes preloaded with NaCl. After acidification and centrifugation the solvent phase was transferred to a test tube preloaded with Na(2)SO(4), incubated for 30 min, centrifuged again, and evaporated in vacuum. The residue was mixed with N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) in acetonitrile, and injected into a GC-MS. When analyzing GBL, the salting-out step was omitted, and analysis was performed with a GC-FID apparatus. As revealed by the validation data this procedure is suitable for quantitative determination of GHB and its precursors in blood and/or urine samples.

  3. The amyloid precursor-like protein (APLP) gene maps to the long arm of human chromosome 19

    SciTech Connect

    Wasco, W.; Tanzi, R.E. ); Brook, J.D. )

    1993-01-01

    We have recently isolated a cDNA from a mouse brain library that encodes a protein whose predicted amino acid sequence is 42% identical and 64% similar to that of the amyloid [beta] protein precursor (APP; 16). This 653-amino-acid amyloid precursor-like protein (APLP) is similar to APP in overall structure as well as amino acid sequence. The amino acid homologies are particularly strong in three distinct regions of the proteins where the identities are 47, 54, and 56% (16). All three of these regions are also conserved in the Drosophila APP-like gene, APPL (11). Notably, 12 cysteine residues and a N -glyco-sylation site are conserved in the extracellular portion of APLP and APP, and a clathrin-binding domain is conserved in the cytoplasmic domain. The cytoplasmic domain is also conserved in a partial CDNA reported to encode an APP-like gene in rat testes (17), These data suggest that APLP and APP are members of a highly conserved gene family. A panel of DNAs from 31 human-rodent somatic cell lines of known karyotype was digested with EcoR1. These DNAs were then probed with the human APLP cDNA clone and the hybridization pattern was consistent with the assignment of the APLP locus to chromosome 19. 17 refs., 1 fig.

  4. Studies Of Residual Flexibility And Vibration Testing

    NASA Technical Reports Server (NTRS)

    Admire, John R.; Tinker, Michael L.; Bookout, Paul S.; Ivey, Edward W.

    1995-01-01

    Collection of reports presents theoretical and experimental studies in which concept of residual flexibility applied to modal vibration testing and verification of mathematical models of vibrations of flexible structure constrained by another structure. "Residual flexibility" denotes that part of interface flexibility due to mode shapes out of frequency range of test. Studies directed toward assessing residual-flexibility approach as substitute for fixed-base vibrational testing of payloads installed in spacecraft.

  5. Residual stresses in polymer matrix composite laminates

    NASA Technical Reports Server (NTRS)

    Hahn, H. T.

    1976-01-01

    Residual stresses in composites are induced during fabrication and by environmental exposure. The theory formulated can describe the shrinkage commonly observed after a thermal expansion test. Comparison between the analysis and experimental data for laminates of various material systems indicates that the residual stress-free temperature can be lower than the curing temperature, depending on the curing process. Effects of residual stresses on ply failure including the acoustic emission characteristics are discussed.

  6. Optical systolic array processor using residue arithmetic

    NASA Technical Reports Server (NTRS)

    Jackson, J.; Casasent, D.

    1983-01-01

    The use of residue arithmetic to increase the accuracy and reduce the dynamic range requirements of optical matrix-vector processors is evaluated. It is determined that matrix-vector operations and iterative algorithms can be performed totally in residue notation. A new parallel residue quantizer circuit is developed which significantly improves the performance of the systolic array feedback processor. Results are presented of a computer simulation of this system used to solve a set of three simultaneous equations.

  7. The isogene 1-deoxy-D-xylulose 5-phosphate synthase 2 controls isoprenoid profiles, precursor pathway allocation, and density of tomato trichomes.

    PubMed

    Paetzold, Heike; Garms, Stefan; Bartram, Stefan; Wieczorek, Jenny; Urós-Gracia, Eva-Maria; Rodríguez-Concepción, Manuel; Boland, Wilhelm; Strack, Dieter; Hause, Bettina; Walter, Michael H

    2010-09-01

    Plant isoprenoids are formed from precursors synthesized by the mevalonate (MVA) pathway in the cytosol or by the methyl-D-erythritol 4-phosphate (MEP) pathway in plastids. Although some exchange of precursors occurs, cytosolic sesquiterpenes are assumed to derive mainly from MVA, while plastidial monoterpenes are produced preferentially from MEP precursors. Additional complexity arises in the first step of the MEP pathway, which is typically catalyzed by two divergent 1-deoxy-D-xylulose 5-phosphate synthase isoforms (DXS1, DXS2). In tomato (Solanum lycopersicum), the SlDXS1 gene is ubiquitously expressed with highest levels during fruit ripening, whereas SlDXS2 transcripts are abundant in only few tissues, including young leaves, petals, and isolated trichomes. Specific down-regulation of SlDXS2 expression was performed by RNA interference in transgenic plants to investigate feedback mechanisms. SlDXS2 down-regulation led to a decrease in the monoterpene β-phellandrene and an increase in two sesquiterpenes in trichomes. Moreover, incorporation of MVA-derived precursors into residual monoterpenes and into sesquiterpenes was elevated as determined by comparison of ¹³C to ¹²C natural isotope ratios. A compensatory up-regulation of SlDXS1 was not observed. Down-regulated lines also exhibited increased trichome density and showed less damage by leaf-feeding Spodoptera littoralis caterpillars. The results reveal novel, non-redundant roles of DXS2 in modulating isoprenoid metabolism and a pronounced plasticity in isoprenoid precursor allocation. PMID:20591838

  8. Residues of profenofos in spring onion.

    PubMed

    Talebi, K; Ghassami, M R

    2004-01-01

    Profenofos is one of the commonly used insecticides in the control of Trips tabaci on spring onion in Iran. Residues of profenofos in spring onion were determined in two different fields under the same conditions. In the first field, onion plants were sprayed with profenofos (40EC) at the rate of 1000 g/ha. Spraying was repeated 2 weeks later. In the second field one spraying was preformed at the same rate. Spring onionwere sampled at different time intervals and analyzed for profenofos residues using a GC equipped with NPD detector. In the first field's samples, the residues were 0.097 and 0.025 mg/kg at 2 and 6 days after spraying, respectively. The residues declined to 0.002 mg/kg on the day twelve. Two days after the second spraying the residues was 0.27 mg/kg, which reduced to 0.032 on the day sixth. However the residues were not detectable 32 days after the second spraying. In the second field, residue levels were 0.193 and 0.043 mg/kg at 2 and 6 days after spraying. Residues, which found after 32 days, were less than 0.001 mg/kg. The rate of residue decay in the first field was higher than the second field. PMID:15756871

  9. Methods of separating particulate residue streams

    DOEpatents

    Hoskinson, Reed L.; Kenney, Kevin L.; Wright, Christopher T.; Hess, J. Richard

    2011-04-05

    A particulate residue separator and a method for separating a particulate residue stream may include an air plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams that are formed by the harvesting device and that travel, at least in part, along the air plenum and in a direction of the second, exhaust end; and a baffle assembly that is located in partially occluding relation relative to the air plenum and that substantially separates the first and second particulate residue air streams.

  10. Possibility to study ionospheric earthquakes precursors using CubeSats

    NASA Astrophysics Data System (ADS)

    Korepanov, Valery; Lappas, Vaios

    It is generally accepted that the earthquakes (EQ) are the most dangerous natural phenomena leading to the multiple losses in human lives and economics. The space observations must be included into the global chain of the EQ precursors monitoring at least as the initial warning to pay greater attention to the ground segment data. As the common opinion agrees, only in combination of multiple observation sites and set of monitored parameters the further progress at the way to raise EQ precursors detection probability may be obtained. There is necessary to answer two important questions before to plan any experiment to study ionospheric precursors of EQ. First one - whether the variations in the ionosphere definitely connected with the EQ preparation process do exist, and the second one - if they do, whether using these signals the precursors of EQ can be reliably identified and used for, if not prediction, then for the warning that the EQ in the given area approaches. The first successful mission dedicated to this problem solution was DEMETER (in orbit during more than 6 years from June 2004 until December 2010). The statistics of this study is impressive: altogether, about 9000 EQs with magnitude larger than M = 5.0 and depth lower than 40 km occurred all over the world during the analyzed period. In the result, the conclusion made there suggests that, obviously, there are real perturbations in the ionosphere connected with the seismic activity, but they are rather weak and at the present stage of data processing may be revealed only with the help of statistical analysis. To realize the study of ionospheric precursors, first it is imperative to clarify the mechanism of energy transfer along the chain “lithosphere-atmosphere-ionosphere”. Many hypotheses of such a mechanism exist, from which the mostly supported are fair weather currents (FWC) and atmospheric gravity waves (AGW), both of which have their pros and contras. The following minimal set of physical

  11. Glutamine: precursor or nitrogen donor for citrulline synthesis?

    PubMed

    Marini, Juan C; Didelija, Inka Cajo; Castillo, Leticia; Lee, Brendan

    2010-07-01

    Although glutamine is considered the main precursor for citrulline synthesis, the current literature does not differentiate between the contribution of glutamine carbon skeleton vs. nonspecific nitrogen (i.e., ammonia) and carbon derived from glutamine oxidation. To elucidate the role of glutamine and nonspecific nitrogen in the synthesis of citrulline, l-[2-(15)N]- and l-[5-(15)N]glutamine and (15)N-ammonium acetate were infused intragastrically in mice. The amino group of glutamine labeled the three nitrogen groups of citrulline almost equally. The amido group and ammonium acetate labeled the ureido and amino groups of citrulline, but not the delta-nitrogen. D(5)-glutamine also infused in this arm of the study, which traces the carbon skeleton of glutamine, was utilized poorly, accounting for only 0.2-0.4% of the circulating citrulline. Dietary glutamine nitrogen (both N groups) incorporation was 25-fold higher than the incorporation of its carbon skeleton into citrulline. To investigate the relative contributions of the carbon skeleton and nonspecific carbon of glutamine, arginine, and proline to citrulline synthesis, U-(13)C(n) tracers of these amino acids were infused intragastrically. Dietary arginine was the main precursor for citrulline synthesis, accounting for approximately 40% of the circulating citrulline. Proline contribution was minor (3.4%), and glutamine was negligible (0.4%). However, the glutamine tracer resulted in a higher enrichment in the ureido group, indicating incorporation of nonspecific carbon from glutamine oxidation into carbamylphosphate used for citrulline synthesis. In conclusion, dietary glutamine is a poor carbon skeleton precursor for the synthesis of citrulline, although it contributes both nonspecific nitrogen and carbon to citrulline synthesis.

  12. Calcemic Fraction-A: Biosynthetic Peptide Precursor of Parathyroid Hormone

    PubMed Central

    Cohn, David V.; Macgregor, Ronal R.; Chu, Luke L. H.; Kimmel, Joe R.; Hamilton, James W.

    1972-01-01

    Calcemic fraction-A (CF-A) is a biologically active, hypercalcemic and bone resorptive peptide, which was detected in, and isolated from, bovine parathyroid glands [Hamilton et al. (1971) Endocrinology 89, 1440-1447]. It has been further purified, and its relationship to parathyroid hormone clarified. The peptide is present in fresh glands at a concentration of about 3 μg/g (parathyroid hormone, 100 μg/g). It contains 109 amino acids (hormone, 84), each of which is present in equal or greater molar ratio than in the hormone. Its molecular weight, calculated from amino-acid composition, is 12,144; determined by dodecyl sulfate-polyacrylamide gel electrophoresis, it is 12,500 (hormone, 9563). Per mole, it reacts with antiserum to parathyroid hormone to an extent of 7-10% that of the hormone, and is about 50% as active in its hypercalcemic and bone resorptive properties in the appropriate assays. Time course and pulse-chase experiments with parathyroid gland slices, in which the incorporation of amino acid into isolated peptide and hormone were measured, indicate that the hormone is made from a protein precursor; the patterns of incorporation of radioactivity are those that would be predicted from a precursor-product relationship. When the large peptide was incubated with parathyroid gland extracts it was partially converted to a molecule that appeared to be the hormone, as based upon its coelution with marker hormone from ion-exchange columns. Finally, tryptic digestion of the peptide increased the immunoreactivity of the sample in accord with the known greater immunoreactivity of the hormone than the peptide. On the basis of these results, it is proposed that the peptide is a biosynthetic precursor of the hormone in bovine parathyroid gland. PMID:4504366

  13. Radiative precursors driven by converging blast waves in noble gases

    SciTech Connect

    Burdiak, G. C.; Lebedev, S. V.; Harvey-Thompson, A. J.; Swadling, G. F.; Suzuki-Vidal, F.; Hall, G. N.; Khoory, E.; Pickworth, L.; Bland, S. N.; Grouchy, P. de; Skidmore, J.; Suttle, L.; Bennett, M.; Niasse, N. P. L.; Williams, R. J. R.; Blesener, K.; Atoyan, L.; Cahill, A.; Hoyt, C.; Potter, W.; and others

    2014-03-15

    A detailed study of the radiative precursor that develops ahead of converging blast waves in gas-filled cylindrical liner z-pinch experiments is presented. The experiment is capable of magnetically driving 20 km s{sup −1} blast waves through gases of densities of the order 10{sup −5} g cm{sup −3} (see Burdiak et al. [High Energy Density Phys. 9(1), 52–62 (2013)] for a thorough description). Data were collected for Ne, Ar, and Xe gas-fills. The geometry of the setup allows a determination of the plasma parameters both in the precursor and across the shock, along a nominally uniform line of sight that is perpendicular to the propagation of the shock waves. Radiation from the shock was able to excite NeI, ArII, and XeII/XeIII precursor spectral features. It is shown that the combination of interferometry and optical spectroscopy data is inconsistent with upstream plasmas being in LTE. Specifically, electron density gradients do not correspond to any apparent temperature change in the emission spectra. Experimental data are compared to 1D radiation hydrodynamics HELIOS-CR simulations and to PrismSPECT atomic physics calculations to assist in a physical interpretation of the observations. We show that upstream plasma is likely in the process of being radiatively heated and that the emission from a small percentage of ionised atoms within a cool background plasma dominates the emission spectra. Experiments were carried out on the MAGPIE and COBRA pulsed-power facilities at Imperial College London and Cornell University, respectively.

  14. Accident Precursor Analysis and Management: Reducing Technological Risk Through Diligence

    NASA Technical Reports Server (NTRS)

    Phimister, James R. (Editor); Bier, Vicki M. (Editor); Kunreuther, Howard C. (Editor)

    2004-01-01

    Almost every year there is at least one technological disaster that highlights the challenge of managing technological risk. On February 1, 2003, the space shuttle Columbia and her crew were lost during reentry into the atmosphere. In the summer of 2003, there was a blackout that left millions of people in the northeast United States without electricity. Forensic analyses, congressional hearings, investigations by scientific boards and panels, and journalistic and academic research have yielded a wealth of information about the events that led up to each disaster, and questions have arisen. Why were the events that led to the accident not recognized as harbingers? Why were risk-reducing steps not taken? This line of questioning is based on the assumption that signals before an accident can and should be recognized. To examine the validity of this assumption, the National Academy of Engineering (NAE) undertook the Accident Precursors Project in February 2003. The project was overseen by a committee of experts from the safety and risk-sciences communities. Rather than examining a single accident or incident, the committee decided to investigate how different organizations anticipate and assess the likelihood of accidents from accident precursors. The project culminated in a workshop held in Washington, D.C., in July 2003. This report includes the papers presented at the workshop, as well as findings and recommendations based on the workshop results and committee discussions. The papers describe precursor strategies in aviation, the chemical industry, health care, nuclear power and security operations. In addition to current practices, they also address some areas for future research.

  15. Nicotiana benthamiana as a Production Platform for Artemisinin Precursors

    PubMed Central

    van Herpen, Teun W. J. M.; Cankar, Katarina; Nogueira, Marilise; Bosch, Dirk; Bouwmeester, Harro J.; Beekwilder, Jules

    2010-01-01

    Background Production of pharmaceuticals in plants provides an alternative for chemical synthesis, fermentation or natural sources. Nicotiana benthamiana is deployed at commercial scale for production of therapeutic proteins. Here the potential of this plant is explored for rapid production of precursors of artemisinin, a sesquiterpenoid compound that is used for malaria treatment. Methodology/Principal Findings Biosynthetic genes leading to artemisinic acid, a precursor of artemisinin, were combined and expressed in N. benthamiana by agro-infiltration. The first committed precursor of artemisinin, amorpha-4,11-diene, was produced upon infiltration of a construct containing amorpha-4,11-diene synthase, accompanied by 3-hydroxy-3-methylglutaryl-CoA reductase and farnesyl diphosphate synthase. Amorpha-4,11-diene was detected both in extracts and in the headspace of the N. benthamiana leaves. When the amorphadiene oxidase CYP71AV1 was co-infiltrated with the amorphadiene-synthesizing construct, the amorpha-4,11-diene levels strongly decreased, suggesting it was oxidized. Surprisingly, no anticipated oxidation products, such as artemisinic acid, were detected upon GC-MS analysis. However, analysis of leaf extracts with a non-targeted metabolomics approach, using LC-QTOF-MS, revealed the presence of another compound, which was identified as artemisinic acid-12-β-diglucoside. This compound accumulated to 39.5 mg.kg−1 fwt. Apparently the product of the heterologous pathway that was introduced, artemisinic acid, is further metabolized efficiently by glycosyl transferases that are endogenous to N. benthamiana. Conclusion/Significance This work shows that agroinfiltration of N. bentamiana can be used as a model to study the production of sesquiterpenoid pharmaceutical compounds. The interaction between the ectopically introduced pathway and the endogenous metabolism of the plant is discussed. PMID:21151979

  16. Precursor times of abnormal b-values prior to mainshocks

    NASA Astrophysics Data System (ADS)

    Wang, Jeen-Hwa; Chen, Kou-Cheng; Leu, Peih-Lin; Chang, Chien-Hsin

    2016-07-01

    Seismic observations exhibit the presence of abnormal b-values prior to numerous earthquakes. The time interval from the appearance of abnormal b-values to the occurrence of mainshock is called the precursor time. There are two kinds of precursor times in use: the first one denoted by T is the time interval from the moment when the b-value starts to increase from the normal one to the abnormal one to the occurrence time of the forthcoming mainshock, and the second one denoted by T p is the time interval from the moment when the abnormal b-value reaches the peak one to the occurrence time of the forthcoming mainshock. Let T* be the waiting time from the moment when the abnormal b-value returned to the normal one to the occurrence time of the forthcoming mainshock. The precursor time, T (usually in days), has been found to be related to the magnitude, M, of the mainshock expected in a linear form as log( T) = q + rM where q and r are the coefficient and slope, respectively. In this study, the values of T, T p , and T* of 45 earthquakes with 3 ≤ M ≤ 9 occurred in various tectonic regions are compiled from or measured from the temporal variations in b-values given in numerous source materials. The relationships of T and T p , respectively, versus M are inferred from compiled data. The difference between the values of T and T p decreases with increasing M. In addition, the plots of T*/ T versus M, T* versus T, and T* versus T- T* will be made and related equations between two quantities will be inferred from given data.

  17. Precursor events and self-organization leading to landslide triggering

    NASA Astrophysics Data System (ADS)

    Lehmann, Peter; Or, Dani

    2010-05-01

    Hillslopes often consist of many interacting soil and land-cover elements differing in hydraulic properties and mechanical strength. Intense rainfall events may result in heterogeneous distribution of hydrologic loading and internal weakening leading to local failure and stress redistribution to neighboring intact units. For certain spatial distributions of hydro-mechanical properties and timing of local failure events, ‘local' failure may propagate across the entire system culminating in landslide release (a ‘global' failure). Such ‘global' event is often preceded by numerous small precursor events (local failures) that theoretically may contain statistical information regarding imminent ‘global' failure and thus could provide certain early warning. We model the system and precursor events by combining concepts of Self-Organized Criticality (SOC) and Fiber Bundle Models (FBM) in a physically-based hydro-mechanical framework. The model consists of hexagonal soil columns connected by fiber bundles at their base and between adjacent elements. Fiber bundles represent mechanical bonds made of numerous connections (fibers) representing friction, roots, cementing agents, water bridges and alike that impart soil strength. Hydrological pathways and load distribution are simulated enabling updating of stresses on fiber bundles. When a bundle fails at element base, stress is redistributed to adjacent connected elements which may initiate a cascade of failures similar to other SOC models (e.g. sand pile model). Increasing hydro-mechanical loads during a rainfall event results in gradual small local fiber failures whose statistics follow a power-law with exponent depending on proximity to global failure. Such state-dependent precursor event statistics could provide a physical basis for field monitoring networks for early warning and hazard prediction. Additionally, the SOC concepts provide a simple framework for landslide susceptibility mapping in space and time and

  18. Molecular Analysis of Precursor Lesions in Familial Pancreatic Cancer

    PubMed Central

    Crnogorac-Jurcevic, Tatjana; Chelala, Claude; Barry, Sayka; Harada, Tomohiko; Bhakta, Vipul; Lattimore, Sam; Jurcevic, Stipo; Bronner, Mary; Lemoine, Nicholas R.; Brentnall, Teresa A.

    2013-01-01

    Background With less than a 5% survival rate pancreatic adenocarcinoma (PDAC) is almost uniformly lethal. In order to make a significant impact on survival of patients with this malignancy, it is necessary to diagnose the disease early, when curative surgery is still possible. Detailed knowledge of the natural history of the disease and molecular events leading to its progression is therefore critical. Methods and Findings We have analysed the precursor lesions, PanINs, from prophylactic pancreatectomy specimens of patients from four different kindreds with high risk of familial pancreatic cancer who were treated for histologically proven PanIN-2/3. Thus, the material was procured before pancreatic cancer has developed, rather than from PanINs in a tissue field that already contains cancer. Genome-wide transcriptional profiling using such unique specimens was performed. Bulk frozen sections displaying the most extensive but not microdissected PanIN-2/3 lesions were used in order to obtain the holistic view of both the precursor lesions and their microenvironment. A panel of 76 commonly dysregulated genes that underlie neoplastic progression from normal pancreas to PanINs and PDAC were identified. In addition to shared genes some differences between the PanINs of individual families as well as between the PanINs and PDACs were also seen. This was particularly pronounced in the stromal and immune responses. Conclusions Our comprehensive analysis of precursor lesions without the invasive component provides the definitive molecular proof that PanIN lesions beget cancer from a molecular standpoint. We demonstrate the need for accumulation of transcriptomic changes during the progression of PanIN to PDAC, both in the epithelium and in the surrounding stroma. An identified 76-gene signature of PDAC progression presents a rich candidate pool for the development of early diagnostic and/or surveillance markers as well as potential novel preventive/therapeutic targets for

  19. Partitioning Residue-derived and Residue-induced Emissions of N2O Using 15N-labelled Crop Residues

    NASA Astrophysics Data System (ADS)

    Farrell, R. E.; Carverhill, J.; Lemke, R.; Knight, J. D.

    2014-12-01

    Estimates of N2O emissions in Canada indicate that 17% of all agriculture-based emissions are associated with the decomposition of crop residues. However, research specific to the western Canadian prairies (including Saskatchewan) has shown that the N2O emission factor for N sources in this region typically ranges between 0.2 and 0.6%, which is well below the current IPCC default emission factor of 1.0%. Thus, it stands to reason that emissions from crop residues should also be lower than those calculated using the current IPCC emission factor. Current data indicates that residue decomposition, N mineralization and N2O production are affected by a number of factors such as C:N ratio and chemical composition of the residue, soil type, and soil water content; thus, a bench-scale incubation study was conducted to examine the effects of soil type and water content on N2O emissions associated with the decomposition of different crop residues. The study was carried out using soils from the Black, Dark Brown, Brown, and Gray soil zones and was conducted at both 50% and 70% water-filled pore space (WFPS); the soils were amended with 15N-labeled residues of wheat, pea, canola, and flax, or with an equivalent amount of 15N-labeled urea; 15N2O production was monitored using a Picarro G5101-i isotopic N2O analyzer. Crop residue additions to the soils resulted in both direct and indirect emissions of N2O, with residue derived emissions (RDE; measured as 15N2O) generally exceeding residue-induced emissions (RIE) at 50% WFPS—with RDEs ranging from 42% to 88% (mean = 58%) of the total N2O. Conversely, at 70% WFPS, RDEs were generally lower than RIEs—ranging from 21% to 83% (mean = 48%). Whereas both water content and soil type had an impact on N2O production, there was a clear and consistent trend in the emission factors for the residues; i.e., emissions were always greatest for the canola residue and lowest for the wheat residue and urea fertilizer; and intermediate for pea

  20. Beryllium-10 in Australasian tektites: evidence for a sedimentary precursor

    SciTech Connect

    Pal, D.K.; Tuniz, C.; Moniot, R.K.; Kruse, T.H.; Herzog, G.F.

    1982-11-19

    Each of seven Australasian tektites contains about 1 x 10/sup 8/ atoms of beryllium-10 (half-life, 1.53 x 10/sup 6/ years) per gram. Cosmic-ray bombardment of the australites cannot have produced the measured amounts of beryllium-10 either at the earth's surface or in space. The beryllium-10 contents of these australites are consistent with a sedimentary precursor that adsorbed from precipitation beryllium-10 produced in the atmosphere. The sediments must have spent several thousand years at the earth's surface within a few million years of the tektite-producing event.

  1. Beryllium-10 in australasian tektites: evidence for a sedimentary precursor.

    PubMed

    Pal, D K; Tuniz, C; Moniot, R K; Kruse, T H; Herzog, G F

    1982-11-19

    Each of seven Australasian tektites contains about 1 x l0(8) atoms of beryllium-10 (half-life, 1.53 x 10(6) years) per gram. Cosmic-ray bombardment of the australites cannot have produced the measured amounts of beryllium-10 either at the earth's surface or in space. The beryllium-10 contents of these australites are consistent with a sedimentary precursor that adsorbed from precipitation beryllium-10 produced in the atmosphere. The sediments must have spent several thousand years at the earth's surface within a few million years of the tektite-producing event.

  2. Transient precursor strategy or very small biological apatite crystals?

    PubMed

    Grynpas, Marc D; Omelon, Sidney

    2007-08-01

    The mechanisms of skeletal mineralization have been studied and debated for decades. Recent Raman spectroscopic identification of octacalcium phosphate-like phosphate ions and possibly amorphous calcium phosphate ions in nascent bone mineral were claimed to support a transient precursor strategy for bone apatite formation. However, this data does not refute the theory that the newest, detectable bone mineral is very small, poorly crystalline biological apatite, because non-apatitic phosphate species have previously been identified in biological apatite and detected on the surfaces of nano-sized hydroxyapatite crystals.

  3. Synthesis of carbon nanotubes using natural carbon precursor: Castor oil

    NASA Astrophysics Data System (ADS)

    Raziah, A. Z.; Junizah, A. R.; Saifuddin, N.

    2012-09-01

    Castor oil has long been an article of commerce due to its versatility as it is widely used as a starting material for many industrial chemical products because of its unique structure. In this study, carbon nanotubes has been synthesized by thermal decomposition of castor oil in nitrogen atmosphere at 300-400δC using custom-made microwave processing unit. The precursor material was catalyzed by iron clusters originating from the addition of ferrocene. The morphology and characterization of the CNTs were studied and discussed by transmission electron microscopy (TEM).

  4. Reaction engineering and precursor film deposition for CIS synthesis

    NASA Astrophysics Data System (ADS)

    Stanbery, B. J.; Davydov, A.; Chang, C. H.; Anderson, T. J.

    1997-02-01

    We present an analysis of alternative reaction pathways for the synthesis of CuInSe2-based films for photovoltaic applications based on our recent and ongoing investigations of the thermochemistry in the Cu-In-Se ternary, Na-Cu-In-Se quaternary, and constituent unary and binary systems. We also describe our efforts to determine the relationship between film growth conditions in our novel rotating-disc system and resultant phase constitution of precursor reactant films intended for subsequent ex-situ rapid thermal processing. A model for the phase chemistry of sodium in CIS films is presented.

  5. Chondrule precursors and cooling paths: The sulfur evidence

    NASA Technical Reports Server (NTRS)

    Zanda, B.; Yu, Y.; Bourot-Denise, M.; Hewins, R. H.; Connolly, H. C., Jr.

    1994-01-01

    The behavior of moderately volatile elements (Na and S) is controversial but critical in understanding chondrule precursors and heating processes. Sulfide appeared to be present in most chondrules, but S should have been vaporized during chondrule formation. In fact, S is extensively redistributed in the course of metamorphism, and its abundance at the end of chondrule formation can only be inferred from the least equilibrated chondrites. Our study of 530 chondrules from Renazzo (CR2) and Semarkona (LL3.0) shows partial volatilization of S during chondrule formation and our melting experiments define conditions for total loss or partial retention of S.

  6. Ozone precursors have regionally variable effect on radiative forcing

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-02-01

    When released near the surface, carbon monoxide, assorted nitrogen oxides (NOx ), and nonmethane hydrocarbons (NMHC) contribute to the production of ozone, a key component of photochemical smog, which is known to have serious deleterious effects on human health. However, when ozone gets lifted into the troposphere, it is a greenhouse gas. That these ozone precursors have such a dual-pronged effect—affecting both human health and the global radiation budget—suggests that mitigating their emissions could be a potential method to both improve air quality and dampen the rate of anthropogenic climate change.

  7. Gelcasting polymeric precursors for producing net-shaped graphites

    DOEpatents

    Klett, James W.; Janney, Mark A.

    2005-02-15

    The present invention discloses a method for molding complex and intricately shaped high density monolithic carbon, carbon-carbon, graphite, and thermoplastic composites using gelcasting technology. The method comprising a polymeric carbon precursor, a solvent, a dispersant, an anti-foaming agent, a monomer system, and an initiator system. The components are combined to form a suspension which is poured into a mold and heat-treated to form a thermoplastic part. The thermoplastic part can then be further densified and heat-treated to produce a high density carbon or graphite composite. The present invention also discloses the products derived from this method.

  8. Lunar Precursor Robotic Program: A Robotic Focus To The Vision

    NASA Technical Reports Server (NTRS)

    French, Raymond A.; Nall, Mark E.

    2007-01-01

    In April 2006, NASA, with help from the commercial and international communities, began developing a global Lunar Exploration Strategy. These activities resulted in themes that expanded on why we should return to the Moon and objectives that identify what we should do when we get there. NASA used these results to develop a Lunar Architecture designed to achieve the subset of the global Lunar Exploration Strategy objectives that fit within NASA's scope. A component of this architecture is the Lunar Precursor Robotic Program. This Program, anticipated to consist of both lunar orbiters and landers, is intended to meet many of NASA's lunar exploration objectives.

  9. Gelcasting polymeric precursors for producing net-shaped graphites

    DOEpatents

    Klett, James W.; Janney, Mark A.

    2002-01-01

    The present invention discloses a method for molding complex and intricately shaped high density monolithic carbon, carbon-carbon, graphite, and thermoplastic composites using gelcasting technology. The method comprising a polymeric carbon precursor, a solvent, a dispersant, an anti-foaming agent, a monomer system, and an initiator system. The components are combined to form a suspension which is poured into a mold and heat-treated to form a thermoplastic part. The thermoplastic part can then be further densified and heat-treated to produce a high density carbon or graphite composite. The present invention also discloses the products derived from this method.

  10. The wireless networking system of Earthquake precursor mobile field observation

    NASA Astrophysics Data System (ADS)

    Wang, C.; Teng, Y.; Wang, X.; Fan, X.; Wang, X.

    2012-12-01

    The mobile field observation network could be real-time, reliably record and transmit large amounts of data, strengthen the physical signal observations in specific regions and specific period, it can improve the monitoring capacity and abnormal tracking capability. According to the features of scatter everywhere, a large number of current earthquake precursor observation measuring points, networking technology is based on wireless broadband accessing McWILL system, the communication system of earthquake precursor mobile field observation would real-time, reliably transmit large amounts of data to the monitoring center from measuring points through the connection about equipment and wireless accessing system, broadband wireless access system and precursor mobile observation management center system, thereby implementing remote instrument monitoring and data transmition. At present, the earthquake precursor field mobile observation network technology has been applied to fluxgate magnetometer array geomagnetic observations of Tianzhu, Xichang,and Xinjiang, it can be real-time monitoring the working status of the observational instruments of large area laid after the last two or three years, large scale field operation. Therefore, it can get geomagnetic field data of the local refinement regions and provide high-quality observational data for impending earthquake tracking forecast. Although, wireless networking technology is very suitable for mobile field observation with the features of simple, flexible networking etc, it also has the phenomenon of packet loss etc when transmitting a large number of observational data due to the wireless relatively weak signal and narrow bandwidth. In view of high sampling rate instruments, this project uses data compression and effectively solves the problem of data transmission packet loss; Control commands, status data and observational data transmission use different priorities and means, which control the packet loss rate within

  11. Survey of volatile oxylipins and their biosynthetic precursors in bryophytes.

    PubMed

    Croisier, Emmanuel; Rempt, Martin; Pohnert, Georg

    2010-04-01

    Oxylipins are metabolites which are derived from the oxidative fragmentation of polyunsaturated fatty acids. These metabolites play central roles in plant hormonal regulation and defense. Here we survey the production of volatile oxylipins in bryophytes and report the production of a high structural variety of C5, C6, C8 and C9 volatiles of mosses. In liverworts and hornworts oxylipin production was not as pronounced as in the 23 screened mosses. A biosynthetic investigation revealed that both, C18 and C20 fatty acids serve as precursors for the volatile oxylipins that are mainly produced after mechanical wounding of the green tissue of mosses.

  12. Cytoplasmic incorporation of a ribonucleic acid precursor in Amoeba proteus.

    PubMed

    PLAUT, W; RUSTAD, R C

    1957-07-25

    The question of RNA synthesis in enucleate cytoplasm of Amoeba has been approached experimentally by incubating enucleate amoebae in a labelled RNA precursor and determining the incorporation into RNA autoradiographically. The results indicate that there is a cytoplasmic incorporation mechanism which can operate in the absence of the nucleus. A comparison is made between Acetabularia and Amoeba with respect to the origins of cytoplasmic RNA. It is concluded that the existing data are consistent with the assumption that some cytoplasmic RNA is of nuclear origin in both organisms.

  13. Glow-discharge synthesis of silicon nitride precursor powders

    SciTech Connect

    Ho, P.; Buss, R.J.; Loehman, R.E. )

    1989-07-01

    A radio-frequency glow discharge is used for the synthesis of submicron, amorphous, silicon nitride precursor powders from silane and ammonia. Powders are produced with a range of Si/N ratios, including stoichiometric, Si-rich, and N-rich, and contain substantial amounts of hydrogen. The powders appear to be similar to silicon diimide and are easily converted to oxide by water vapor. The powders lose weight and crystallize to a mixture of {alpha} and {beta}-Si{sub 3}N{sub 4} after prolonged heating at 1600{degree}C. Studies of spectrally and spatially resolved optical emission from the plasma are reported.

  14. Graphene nanoribbons synthesized from molecular precursor polymerization on Au(110)

    SciTech Connect

    Massimi, Lorenzo; Ourdjini, Oualid; Della Pia, Ada; Mariani, Carlo; Betti, Maria Grazia; Cavaliere, Emanuele; Gavioli, Luca

    2015-06-23

    A spectroscopic study of 10,10-dibromo-9,9 bianthracene (DBBA) molecules deposited on the Au(110) surface is presented, by means of ultraviolet and X-ray photoemission, and X-ray absorption spectroscopy. Through a thermally activated procedure, these molecular precursors polymerize and eventually form graphene nanoribbons (GNRs) with atomically controlled shape and width, very important building blocks for several technological applications. The GNRs observed by scanning tunneling microscopy (STM) appear as short segments on top of the gold surface reconstruction, pointing out the delicate balance among surface diffusion and surface corrugation in their synthesis on the Au(110) surface.

  15. Imaging Transition Zone Thickness Beneath South America from SS Precursors

    NASA Astrophysics Data System (ADS)

    Schmerr, N.; Garnero, E.

    2006-12-01

    We image detailed upper mantle discontinuity structure beneath a number of geologically active regions, including the South American subduction zone, the Scotia plate subduction zone, and several volcanic hotspots (e.g., the Galapagos Islands), in a region ~10,000 km by 10,000 km wide, spanning 70° S to 20° N and 20° W to 110° W. Precursors to the seismic phase SS are analyzed, which form as a result of underside reflections off seismic discontinuities beneath the midpoint of the SS path and are highly sensitive to discontinuity depth and sharpness. Our SS dataset consists of over 15,000 high-quality transverse component broadband displacement seismograms collected from the Incorporated Research Institutions for Seismology (IRIS), the Canadian National Seismic Network (CNSN), as well as data from EarthScope seismic stations, and from the Canadian Northwest Experiment (CANOE) temporary broadband array deployment. This dataset densely samples several regions in our study area and significantly improves the sampling for this area compared to previous precursor studies. Data with common central SS bouncepoints are stacked to enhance precursory phases. Solution discontinuity structure depends on a number of factors, including dominant seismic period, crustal correction, signal-to-noise ratio threshold, and tomography model used for mantle heterogeneity correction. We exclude precursor data predicted to interfere with other seismic phases, such as topside reflections (e.g., s670sS), which have been demonstrated to contaminate final stacks. Solution transition zone thickness is at least 20 km thicker than global average estimates of 242 km along the northwestern portion of the South American subduction complex (Peru, Ecuador, and Columbia); this thickening extends 1000-1500 km to the east beneath the continent, but does not appear to continue south of -20° latitude along the convergent margin. A minimum of 10 km of thickening is imaged to the west of the Scotia

  16. Superhydrophobic Ceramic Coatings by Solution Precursor Plasma Spray

    NASA Astrophysics Data System (ADS)

    Cai, Yuxuan; Coyle, Thomas W.; Azimi, Gisele; Mostaghimi, Javad

    2016-04-01

    This work presents a novel coating technique to manufacture ceramic superhydrophobic coatings rapidly and economically. A rare earth oxide (REO) was selected as the coating material due to its hydrophobic nature, chemical inertness, high temperature stability, and good mechanical properties, and deposited on stainless steel substrates by solution precursor plasma spray (SPPS). The effects of various spraying conditions including standoff distance, torch power, number of torch passes, types of solvent and plasma velocity were investigated. The as-sprayed coating demonstrated a hierarchically structured surface topography, which closely resembles superhydrophobic surfaces found in nature. The water contact angle on the SPPS superhydrophobic coating was up to 65% higher than on smooth REO surfaces.

  17. Review: R28 retinal precursor cells: The first 20 years

    PubMed Central

    2014-01-01

    The R28 retinal precursor cell line was established 20 years ago, originating from a postnatal day 6 rat retinal culture immortalized with the 12S E1A (NP-040507) gene of the adenovirus in a replication-incompetent viral vector. Since that time, R28 cells have been characterized and used for a variety of in vitro and in vivo studies of retinal cell behavior, including differentiation, neuroprotection, cytotoxicity, and light stimulation, as well as retinal gene expression and neuronal function. While no cell culture is equivalent to the intact eye, R28 cells continue to provide an important experimental system for the study of many retinal processes. PMID:24644404

  18. Endophytic fungi as a source of biofuel precursors.

    PubMed

    Santos-Fo, Florisvaldo; Fill, Taicia Pacheco; Nakamura, Joanita; Monteiro, Marcos Roberto; Rodrigues-Fo, Edson

    2011-07-01

    Endophytic fungi, isolated from a number of different species of tropical plants, were investigated for lipid biodiesel precursor production. The extracts produced from liquid cultures of these fungi were subjected to acidcatalyzed transesterification reactions with methanol producing methyl esters and then analyzed through chromatographic (GC-FID) and spectrometric techniques (MS, NMR ¹H). The European Standard Method, EN 14103, was used for the quantification of methyl esters extracted from the fungi of the species and genera studied. Xylariaceous fungi exhibited the highest concentrations of methyl esters (91%), and hence may be a promising source for biofuel.

  19. Beryllium-10 in Australasian tektites - Evidence for a sedimentary precursor

    NASA Technical Reports Server (NTRS)

    Pal, D. K.; Moniot, R. K.; Kruse, T. H.; Herzog, G. F.; Tuniz, C.

    1982-01-01

    Each of seven Australasian tektites contains about 100 micron atoms of beryllium-10 (half-life, 1.53 million years) per gram. Cosmic-ray bombardment of the australites cannot have produced the measured amounts of beryllium-10 either at the earth's surface or in space. The beryllium-10 contents of these australites are consistent with a sedimentary precursor that adsorbed from precipitation beryllium-10 produced in the atmosphere. The sediments must have spent several thousand years at the earth's surface within a few million years of the tektite-producing event.

  20. Beryllium-10 in australasian tektites: evidence for a sedimentary precursor.

    PubMed

    Pal, D K; Tuniz, C; Moniot, R K; Kruse, T H; Herzog, G F

    1982-11-19

    Each of seven Australasian tektites contains about 1 x l0(8) atoms of beryllium-10 (half-life, 1.53 x 10(6) years) per gram. Cosmic-ray bombardment of the australites cannot have produced the measured amounts of beryllium-10 either at the earth's surface or in space. The beryllium-10 contents of these australites are consistent with a sedimentary precursor that adsorbed from precipitation beryllium-10 produced in the atmosphere. The sediments must have spent several thousand years at the earth's surface within a few million years of the tektite-producing event. PMID:17771035

  1. Proliferative and transcriptional identity of distinct classes of neural precursors in the mammalian olfactory epithelium

    PubMed Central

    Tucker, Eric S.; Lehtinen, Maria K.; Maynard, Tom; Zirlinger, Mariela; Dulac, Catherine; Rawson, Nancy; Pevny, Larysa; LaMantia, Anthony-Samuel

    2010-01-01

    Neural precursors in the developing olfactory epithelium (OE) give rise to three major neuronal classes – olfactory receptor (ORNs), vomeronasal (VRNs) and gonadotropin releasing hormone (GnRH) neurons. Nevertheless, the molecular and proliferative identities of these precursors are largely unknown. We characterized two precursor classes in the olfactory epithelium (OE) shortly after it becomes a distinct tissue at midgestation in the mouse: slowly dividing self-renewing precursors that express Meis1/2 at high levels, and rapidly dividing neurogenic precursors that express high levels of Sox2 and Ascl1. Precursors expressing high levels of Meis genes primarily reside in the lateral OE, whereas precursors expressing high levels of Sox2 and Ascl1 primarily reside in the medial OE. Fgf8 maintains these expression signatures and proliferative identities. Using electroporation in the wild-type embryonic OE in vitro as well as Fgf8, Sox2 and Ascl1 mutant mice in vivo, we found that Sox2 dose and Meis1 – independent of Pbx co-factors – regulate Ascl1 expression and the transition from lateral to medial precursor state. Thus, we have identified proliferative characteristics and a dose-dependent transcriptional network that define distinct OE precursors: medial precursors that are most probably transit amplifying neurogenic progenitors for ORNs, VRNs and GnRH neurons, and lateral precursors that include multi-potent self-renewing OE neural stem cells. PMID:20573694

  2. XANES Analysis of Organic Residues Produced from the UV Irradiation of Astrophysical Ice Analogs

    NASA Technical Reports Server (NTRS)

    Nuevo, M.; Milam, S N.; Sandford, S A.; De Gregorio, B T.; Cody, G D.; Kilcoyne, A L.

    2011-01-01

    Organic residues formed in the laboratory from the ultraviolet (UV) photo-irradiation or ion bombardment of astrophysical ice analogs have been extensively studied for the last 15 years with a broad suite of techniques, including infrared (IR) and UV spectroscopies, as well as mass spectrometry. Analyses of these materials show that they consist of complex mixtures of organic compounds stable at room temperature, mostly soluble, that have not been fully characterized. However, the hydrolysis products of these residues have been partly identified using chromatography techniques, which indicate that they contain molecular precursors of prebiotic interest such as amino acids, nitrile-bearing compounds, and amphiphilic compounds. In this study, we present the first X-ray absorption near-edge structure (XANES) spectroscopy measurements of three organic residues made from the UV irradiation of ices having different starting compositions. XANES spectra confirm the presence of different chemical functions in these residues, and indicate that they are rich in nitrogenand oxygen-bearing species. These data can be compared with XANES measurements of extraterrestrial materials. Finally, this study also shows how soft X rays can alter the chemical composition of samples.

  3. Oxidation of methionine residues in polypeptide ions via gas-phase ion/ion chemistry.

    PubMed

    Pilo, Alice L; McLuckey, Scott A

    2014-06-01

    The gas-phase oxidation of methionine residues is demonstrated here using ion/ion reactions with periodate anions. Periodate anions are observed to attach in varying degrees to all polypeptide ions irrespective of amino acid composition. Direct proton transfer yielding a charge-reduced peptide ion is also observed. In the case of methionine and, to a much lesser degree, tryptophan-containing peptide ions, collisional activation of the complex ion generated by periodate attachment yields an oxidized peptide product (i.e., [M + H + O](+)), in addition to periodic acid detachment. Detachment of periodic acid takes place exclusively for peptides that do not contain either a methionine or tryptophan side chain. In the case of methionine-containing peptides, the [M + H + O](+) product is observed at a much greater abundance than the proton transfer product (viz., [M + H](+)). Collisional activation of oxidized Met-containing peptides yields a signature loss of 64 Da from the precursor and/or product ions. This unique loss corresponds to the ejection of methanesulfenic acid from the oxidized methionine side chain and is commonly used in solution-phase proteomics studies to determine the presence of oxidized methionine residues. The present work shows that periodate anions can be used to 'label' methionine residues in polypeptides in the gas phase. The selectivity of the periodate anion for the methionine side chain suggests several applications including identification and location of methionine residues in sequencing applications.

  4. Oxidation of Methionine Residues in Polypeptide Ions Via Gas-Phase Ion/Ion Chemistry

    NASA Astrophysics Data System (ADS)

    Pilo, Alice L.; McLuckey, Scott A.

    2014-06-01

    The gas-phase oxidation of methionine residues is demonstrated here using ion/ion reactions with periodate anions. Periodate anions are observed to attach in varying degrees to all polypeptide ions irrespective of amino acid composition. Direct proton transfer yielding a charge-reduced peptide ion is also observed. In the case of methionine and, to a much lesser degree, tryptophan-containing peptide ions, collisional activation of the complex ion generated by periodate attachment yields an oxidized peptide product (i.e., [M + H + O]+), in addition to periodic acid detachment. Detachment of periodic acid takes place exclusively for peptides that do not contain either a methionine or tryptophan side chain. In the case of methionine-containing peptides, the [M + H + O]+ product is observed at a much greater abundance than the proton transfer product (viz., [M + H]+). Collisional activation of oxidized Met-containing peptides yields a signature loss of 64 Da from the precursor and/or product ions. This unique loss corresponds to the ejection of methanesulfenic acid from the oxidized methionine side chain and is commonly used in solution-phase proteomics studies to determine the presence of oxidized methionine residues. The present work shows that periodate anions can be used to `label' methionine residues in polypeptides in the gas phase. The selectivity of the periodate anion for the methionine side chain suggests several applications including identification and location of methionine residues in sequencing applications.

  5. Development and method validation for the determination of nitroimidazole residues in salmon, tilapia and shrimp muscle.

    PubMed

    Watson, Lynn; Potter, Ross; MacNeil, James D; Murphy, Cory

    2014-01-01

    The use of nitroimidazoles in aquacultured fish has been banned in many countries due to the suspected mutagenic and carcinogenic effects of these compounds. In response to the need to conduct residue testing of these compounds in fish, a simple, rapid, and sensitive method was developed and validated that is suitable for regulatory monitoring of nitroimidazole residues and their hydroxy metabolites in fish muscle tissue. Following solvent extraction of homogenized tissue and clean-up using a C18 SPE cartridge, analyses were conducted by ultra-performance UPLC-MS/MS. A precursor ion and two product ions were monitored for each of the parent compounds and metabolites included in the method. The validated method has an analytical range from 1 to 50 ng/g in the representative species (tilapia, salmon, and shrimp), with an LOD and LOQ ranging from 0.07 to 1.0 nglg and 0.21 to 3.0 nglg, respectively, depending on the analyte. Recoveries ranged from 81 to 124% and repeatability was between 4 and 17%. HorRat values were within typical limits of acceptability for a single laboratory. Working standards were stable for 12 months, extracts were stable for 5 days, and tissues for 2 months under appropriate storage conditions. This method was determined to be suitable for routine use for screening, quantification, and confirmation of nitroimidazole residues in a residue monitoring program for fish with regulatory oversight.

  6. A Benchmark Study on Casting Residual Stress

    SciTech Connect

    Johnson, Eric M.; Watkins, Thomas R; Schmidlin, Joshua E; Dutler, S. A.

    2012-01-01

    Stringent regulatory requirements, such as Tier IV norms, have pushed the cast iron for automotive applications to its limit. The castings need to be designed with closer tolerances by incorporating hitherto unknowns, such as residual stresses arising due to thermal gradients, phase and microstructural changes during solidification phenomenon. Residual stresses were earlier neglected in the casting designs by incorporating large factors of safety. Experimental measurement of residual stress in a casting through neutron or X-ray diffraction, sectioning or hole drilling, magnetic, electric or photoelastic measurements is very difficult and time consuming exercise. A detailed multi-physics model, incorporating thermo-mechanical and phase transformation phenomenon, provides an attractive alternative to assess the residual stresses generated during casting. However, before relying on the simulation methodology, it is important to rigorously validate the prediction capability by comparing it to experimental measurements. In the present work, a benchmark study was undertaken for casting residual stress measurements through neutron diffraction, which was subsequently used to validate the accuracy of simulation prediction. The stress lattice specimen geometry was designed such that subsequent castings would generate adequate residual stresses during solidification and cooling, without any cracks. The residual stresses in the cast specimen were measured using neutron diffraction. Considering the difficulty in accessing the neutron diffraction facility, these measurements can be considered as benchmark for casting simulation validations. Simulations were performed using the identical specimen geometry and casting conditions for predictions of residual stresses. The simulation predictions were found to agree well with the experimentally measured residual stresses. The experimentally validated model can be subsequently used to predict residual stresses in different cast

  7. Strain-induced dimensionality crossover of precursor modulations in Ni{sub 2}MnGa

    SciTech Connect

    Nie, Zhihua E-mail: ydwang@neu.edu.cn; Wang, Yandong E-mail: ydwang@neu.edu.cn; Shang, Shunli; Wang, Yi; Liu, Zi-Kui; Zeng, Qiaoshi; Ren, Yang; Liu, Dongmei; Yang, Wenge

    2015-01-12

    Precursor modulations often occur in functional materials like magnetic shape memory alloys, ferroelectrics, and superconductors. In this letter, we have revealed the underlying mechanism of the precursor modulations in ferromagnetic shape memory alloys Ni{sub 2}MnGa by combining synchrotron-based x-ray diffraction experiments and first-principles phonon calculations. We discovered the precursor modulations along [011] direction can be eliminated with [001] uniaxial loading, while the precursor modulations or premartensite can be totally suppressed by hydrostatic pressure condition. The TA{sub 2} phonon anomaly is sensitive to stress induced lattice strain, and the entire TA{sub 2} branch is stabilized along the directions where precursor modulations are eliminated by external stress. Our discovery bridges precursor modulations and phonon anomalies, and sheds light on the microscopic mechanism of the two-step superelasticity in precursor martensite.

  8. Strain-induced dimensionality crossover of precursor modulations in Ni2MnGa

    SciTech Connect

    Nie, Zhihua; Wang, Yandong; Shang, Shunli; Zeng, Qiaoshi; Ren, Yang; Liu, Dongmei; Yang, Wenge; Wang, Yi; Liu, Zi-Kui

    2015-01-01

    Precursor modulations often occur in functional materials like magnetic shape memory alloys, ferroelectrics, and superconductors. In this letter, we have revealed the underlying mechanism of the precursor modulations in ferromagnetic shape memory alloys Ni2MnGa by combining synchrotron-based x-ray diffraction experiments and first-principles phonon calculations. We discovered the precursor modulations along [011] direction can be eliminated with [001] uniaxial loading, while the precursor modulations or premartensite can be totally suppressed by hydrostatic pressure condition. The TA2 phonon anomaly is sensitive to stress induced lattice strain, and the entire TA2 branch is stabilized along the directions where precursor modulations are eliminated by external stress. Our discovery bridges precursor modulations and phonon anomalies, and sheds light on the microscopic mechanism of the two-step superelasticity in precursor martensite.

  9. Gunshot residue preservation in seawater.

    PubMed

    Lindström, Anne-Christine; Hoogewerff, Jurian; Athens, Josie; Obertova, Zuzana; Duncan, Warwick; Waddell, Neil; Kieser, Jules

    2015-08-01

    Little is known about the persistence of gunshot residue (GSR) in soft tissue and bones during decomposition in marine environments. For a better understanding, qualitative and quantitative data were obtained on GSR retention on soft tissue and bony gunshot wounds (GSWs). A quantity of 36 fleshed and 36 defleshed bovine ribs were shot at contact range with 0.22 calibre hollow point ammunition using a Stirling 0.22 calibre long rifle. Bone specimens in triplicate were placed in three environments: submerged, intertidal and in supralittoral zone. Sets of triplicates were recovered on day 3, 10, 24 and 38, and analysed with scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDX), and inductive coupled plasma mass spectrometry (ICP-MS). The SEM-EDX recorded GSR-indicative particles surrounding the bullet entrance on all bone types (fleshed and defleshed) in all environments throughout the study. GSR-unique particles were only detected on the supralittoral bones. The ICP-MS analysis showed faster GSR loss on submerged than intertidal and supralittoral defleshed specimens. Fleshed specimens showed a faster GSR loss on intertidal than submerged and supralittoral specimens. In conclusion, the GSR disappeared faster from submerged and intertidal than non-submerged specimens. The difference of detection of GSR between analysed specimens (defleshed versus fleshed) disappeared upon defleshing. This study highlights the potential of finding evidence of GSR in a submerged body and the potential of microscopic and analytical methods for examining suspected GSW in highly decomposed bodies in marine habitats.

  10. Thermal Insulation from Hardwood Residues

    NASA Astrophysics Data System (ADS)

    Sable, I.; Grinfelds, U.; Vikele, L.; Rozenberga, L.; Zeps, M.; Luguza, S.

    2015-11-01

    Adequate heat is one of the prerequisites for human wellbeing; therefore, building insulation is required in places where the outside temperature is not suitable for living. The climate change, with its rising temperatures and longer dry periods, promotes enlargement of the regions with conditions more convenient for hardwood species than for softwood species. Birch (Betula pendula) is the most common hardwood species in Latvia. The aim of this work was to obtain birch fibres from wood residues of plywood production and to form low-density thermal insulation boards. Board formation and production was done in the presence of water; natural binder, fire retardant and fungicide were added in different concentrations. Board properties such as density, transportability or resistance to particulate loss, thermal conductivity and reaction to fire were investigated. This study included thermal insulation boards with the density of 102-120 kg/m3; a strong correlation between density and the binder amount was found. Transportability also improved with the addition of a binder, and 0.1-0.5% of the binder was the most appropriate amount for this purpose. The measured thermal conductivity was in the range of 0.040-0.043 W/(m·K). Fire resistance increased with adding the fire retardant. We concluded that birch fibres are applicable for thermal insulation board production, and it is possible to diversify board properties, changing the amount of different additives.

  11. Catalyst deactivation in residue hydrocracking

    SciTech Connect

    Oballa, M.C.; Wong, C.; Krzywicki, A.

    1994-12-31

    The existence of a computer-controlled bench scale hydrocracking units at the authors site has made cheaper the non-stop running of experiments for long periods of time. It was, therefore possible to show, at minimal costs, when three hydrocracking catalysts in service reach their maximum lifetime. Different parameters which are helpful for catalyst life and activity predictions were calculated, e.g., relative catalyst age and the effectiveness factor. Experimental results compared well with model, giving them the minimum and maximum catalyst lifetime, as well as the deactivation profile with regard to sulfur and metals removal. Reaction rate constants for demetallization and desulfurization were also determined. Six commercial catalysts were evaluated at short term runs and the three most active were used for long term runs. Out of three catalysts tested for deactivation at long term runs, it was possible to choose one whose useful life was higher than the others. All runs were carried out in a Robinson-Mahoney continuous flow stirred tank reactor, using 50/50 volumetric mixture of Cold Lake/Lloydminster atmospheric residue and NiMo/Al{sub 2}O{sub 3} catalyst.

  12. Characterization Report on Sand, Slag, and Crucible Residues and on Fluoride Residues

    SciTech Connect

    Murray, A.M.

    1999-02-10

    This paper reports on the chemical characterization of the sand, slag, and crucible (SS and C) residues and the fluoride residues that may be shipped from the Rocky Flats Environmental Technology Site (RFETS) to Savannah River Site (SRS).

  13. Use of Combined Uncertainty of Pesticide Residue Results for Testing Compliance with Maximum Residue Limits (MRLs).

    PubMed

    Farkas, Zsuzsa; Slate, Andrew; Whitaker, Thomas B; Suszter, Gabriella; Ambrus, Árpád

    2015-05-13

    The uncertainty of pesticide residue levels in crops due to sampling, estimated for 106 individual crops and 24 crop groups from residue data obtained from supervised trials, was adjusted with a factor of 1.3 to accommodate the larger variability of residues under normal field conditions. Further adjustment may be necessary in the case of mixed lots. The combined uncertainty of residue data including the contribution of sampling is used for calculation of an action limit, which should not be exceeded when compliance with maximum residue limits is certified as part of premarketing self-control programs. On the contrary, for testing compliance of marketed commodities the residues measured in composite samples should be greater than or equal to the decision limit calculated only from the combined uncertainty of the laboratory phase of the residue determination. The options of minimizing the combined uncertainty of measured residues are discussed. The principles described are also applicable to other chemical contaminants. PMID:25658668

  14. Persistence of perfluoroalkyl acid precursors in AFFF-impacted groundwater and soil.

    PubMed

    Houtz, Erika F; Higgins, Christopher P; Field, Jennifer A; Sedlak, David L

    2013-08-01

    Several classes of polyfluorinated chemicals that are potential precursors to the perfluorinated carboxylates and sulfonates are present in aqueous film-forming foams (AFFF). To assess the persistence of these AFFF-derived precursors, groundwater, soil, and aquifer solids were obtained in 2011 from an unlined firefighter training area at a U.S. Air Force Base where AFFF was regularly used between 1970 and 1990. To measure the total concentration of perfluorinated carboxylate and sulfonate precursors in archived AFFF formulations and AFFF-impacted environmental samples, a previously developed assay that uses hydroxyl radical to oxidize precursors to perfluorinated carboxylates was adapted for these media. This assay was employed along with direct measurement of 22 precursors found in AFFF and a suite of other poly- and perfluoroalkyl substances (PFASs). On a molar basis, precursors accounted for 41-100% of the total concentration of PFASs in archived AFFF formulations. In the training area, precursors measured by the oxidation assay accounted for an average of 23% and 28% of total PFASs (i.e., precursors and perfluorinated carboxylates and sulfonates) in groundwater and solids samples, respectively. One precursor in AFFF, perfluorohexane sulfonamide amine, was observed on several highly contaminated soil and aquifer solids samples, but no other precursors present in AFFF formulations were detected in any samples at this field site. Suspected intermediate transformation products of precursors in AFFF that were directly measured accounted for approximately half of the total precursor concentration in samples from the training site. The fraction of PFASs consisting of perfluorinated carboxylates and sulfonates was greater in groundwater and solid samples than in any archived AFFF formulations, suggesting that much of the mass of precursors released at the site was converted to perfluorinated carboxylates and sulfonates. The precursors that have persisted at this site

  15. Effect of nitrogen fertilization and residue management practices on ammonia emissions from subtropical sugarcane production

    NASA Astrophysics Data System (ADS)

    Dattamudi, Sanku; Wang, Jim J.; Dodla, Syam Kumar; Arceneaux, Allen; Viator, H. P.

    2016-08-01

    Ammonia (NH3) emission from soil is a loss of nitrogen (N) nutrient for plant production as well as an issue of air quality, due to the fact that it is an active precursor of airborne particulate matters. Ammonia also acts as a secondary source of nitrous oxide (N2O) emission when present in the soil. In this study, the impacts of different sources of N fertilizers and harvest residue management schemes on NH3 emissions from sugarcane production were evaluated based on an active chamber method. The field experiment plots consisting of two sources of N fertilizer (urea and urea ammonium nitrate (UAN)) and two common residue management practices, namely residue retained (RR) and residue burned (RB), were established on a Commerce silt loam. The NH3 volatilized following N fertilizer application was collected in an impinger containing diluted citric acid and was subsequently analyzed using ion chromatography. The NH3 loss was primarily found within 3-4 weeks after N application. Average seasonal soil NH3 flux was significantly greater in urea plots with NH3-N emission factor (EF) twice or more than in UAN plots (2.4-5.6% vs. 1.2-1.7%). The RR residue management scheme had much higher NH3 volatilization than the RB treatment regardless of N fertilizer sources, corresponding to generally higher soil moisture levels in the former. Ammonia-N emissions in N fertilizer-treated sugarcane fields increased with increasing soil water-filled pore space (WFPS) up to 45-55% observed in the field. Both N fertilizer sources and residue management approaches significantly affected NH3 emissions.

  16. Perfluoroalkyl Acids (PFAAs) and Selected Precursors in the Baltic Sea Environment: Do Precursors Play a Role in Food Web Accumulation of PFAAs?

    PubMed

    Gebbink, Wouter A; Bignert, Anders; Berger, Urs

    2016-06-21

    The present study examined the presence of perfluoroalkyl acids (PFAAs) and selected precursors in the Baltic Sea abiotic environment and guillemot food web, and investigated the relative importance of precursors in food web accumulation of PFAAs. Sediment, water, zooplankton, herring, sprat, and guillemot eggs were analyzed for perfluoroalkane sulfonic acids (PFSAs; C4,6,8,10) and perfluoroalkyl carboxylic acids (PFCAs; C6-15) along with six perfluoro-octane sulfonic acid (PFOS) precursors and 11 polyfluoroalkyl phosphoric acid diesters (diPAPs). FOSA, FOSAA and its methyl and ethyl derivatives (Me- and EtFOSAA), and 6:2/6:2 diPAP were detected in sediment and water. While FOSA and the three FOSAAs were detected in all biota, a total of nine diPAPs were only detected in zooplankton. Concentrations of PFOS precursors and diPAPs exceeded PFOS and PFCA concentrations, respectively, in zooplankton, but not in fish and guillemot eggs. Although PFOS precursors were present at all trophic levels, they appear to play a minor role in food web accumulation of PFOS based on PFOS precursor/PFOS ratios and PFOS and FOSA isomer patterns. The PFCA pattern in fish could not be explained by the intake pattern based on PFCAs and analyzed precursors, that is, diPAPs. Exposure to additional precursors might therefore be a dominant exposure pathway compared to direct PFCA exposure for fish.

  17. Methods of making copper selenium precursor compositions with a targeted copper selenide content and precursor compositions and thin films resulting therefrom

    DOEpatents

    Curtis, Calvin J.; Miedaner, Alexander; van Hest, Marinus Franciscus Antonius Maria; Ginley, David S.; Leisch, Jennifer; Taylor, Matthew; Stanbery, Billy J.

    2011-09-20

    Precursor compositions containing copper and selenium suitable for deposition on a substrate to form thin films suitable for semi-conductor applications. Methods of forming the precursor compositions using primary amine solvents and methods of forming the thin films wherein the selection of temperature and duration of heating controls the formation of a targeted species of copper selenide.

  18. Perfluoroalkyl Acids (PFAAs) and Selected Precursors in the Baltic Sea Environment: Do Precursors Play a Role in Food Web Accumulation of PFAAs?

    PubMed

    Gebbink, Wouter A; Bignert, Anders; Berger, Urs

    2016-06-21

    The present study examined the presence of perfluoroalkyl acids (PFAAs) and selected precursors in the Baltic Sea abiotic environment and guillemot food web, and investigated the relative importance of precursors in food web accumulation of PFAAs. Sediment, water, zooplankton, herring, sprat, and guillemot eggs were analyzed for perfluoroalkane sulfonic acids (PFSAs; C4,6,8,10) and perfluoroalkyl carboxylic acids (PFCAs; C6-15) along with six perfluoro-octane sulfonic acid (PFOS) precursors and 11 polyfluoroalkyl phosphoric acid diesters (diPAPs). FOSA, FOSAA and its methyl and ethyl derivatives (Me- and EtFOSAA), and 6:2/6:2 diPAP were detected in sediment and water. While FOSA and the three FOSAAs were detected in all biota, a total of nine diPAPs were only detected in zooplankton. Concentrations of PFOS precursors and diPAPs exceeded PFOS and PFCA concentrations, respectively, in zooplankton, but not in fish and guillemot eggs. Although PFOS precursors were present at all trophic levels, they appear to play a minor role in food web accumulation of PFOS based on PFOS precursor/PFOS ratios and PFOS and FOSA isomer patterns. The PFCA pattern in fish could not be explained by the intake pattern based on PFCAs and analyzed precursors, that is, diPAPs. Exposure to additional precursors might therefore be a dominant exposure pathway compared to direct PFCA exposure for fish. PMID:27192404

  19. Two key polymorphisms in a newly discovered allele of the Vitis vinifera TPS24 gene are responsible for the production of the rotundone precursor α-guaiene

    PubMed Central

    Drew, Damian Paul; Andersen, Trine Bundgaard; Sweetman, Crystal; Møller, Birger Lindberg; Ford, Christopher; Simonsen, Henrik Toft

    2016-01-01

    Rotundone was initially identified as a grape-derived compound responsible for the peppery aroma of Shiraz wine varieties. It has subsequently been found in black and white pepper and several other spices. Because of its potent aroma, the molecular basis for rotundone formation is of particular relevance to grape and wine scientists and industry. We have identified and functionally characterized in planta a sesquiterpene synthase, VvGuaS, from developing grape berries, and have demonstrated that it produces the precursor of rotundone, α-guaiene, as its main product. The VvGuaS enzyme is a novel allele of the sesquiterpene synthase gene, VvTPS24, which has previously been reported to encode VvPNSeInt, an enzyme that produces a variety of selinene-type sesquiterpenes. This newly discovered VvTPS24 allele encodes an enzyme 99.5% identical to VvPNSeInt, with the differences comprising just 6 out of the 561 amino acid residues. Molecular modelling of the enzymes revealed that two of these residues, T414 and V530, are located in the active site of VvGuaS within 4 Å of the binding-site of the substrate, farnesyl pyrophosphate. Mutation of these two residues of VvGuaS into the corresponding polymorphisms in VvPNSeInt results in a complete functional conversion of one enzyme into the other, while mutation of each residue individually produces an intermediate change in the product profile. We have therefore demonstrated that VvGuaS, an enzyme responsible for production of the rotundone precursor, α-guaiene, is encoded by a novel allele of the previously characterized grapevine gene VvTPS24 and that two specific polymorphisms are responsible for functional differences between VvTPS24 alleles. PMID:26590310

  20. 48 CFR 1450.104 - Residual powers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Residual powers. 1450.104 Section 1450.104 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR CONTRACT MANAGEMENT EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 1450.104 Residual powers....

  1. BOOSTER CHLORINATION FOR MANAGING DISINFECTANT RESIDUALS

    EPA Science Inventory

    Booster chlorination is an approach to residual maintenance in which chlorine is applied at strategic locations within the distribution system. Situations in which booster chlorination may be most effective for maintaining a residual are explained informally in the context of a ...

  2. Crop Residues: The Rest of the Story

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A recent scientific publication stated that to remove CO2 from the atmosphere, the most permanent and rapid solution would be to sink crop residues to the ocean floor where they would be buried in deep ocean sediments. However, mitigating rising atmospheric CO2 concentrations by removing crop residu...

  3. 40 CFR 240.208 - Residue.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Residue. 240.208 Section 240.208 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES GUIDELINES FOR THE THERMAL PROCESSING OF SOLID WASTES Requirements and Recommended Procedures § 240.208 Residue....

  4. 40 CFR 240.208 - Residue.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Residue. 240.208 Section 240.208 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES GUIDELINES FOR THE THERMAL PROCESSING OF SOLID WASTES Requirements and Recommended Procedures § 240.208 Residue....

  5. 40 CFR 240.208 - Residue.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Residue. 240.208 Section 240.208 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES GUIDELINES FOR THE THERMAL PROCESSING OF SOLID WASTES Requirements and Recommended Procedures § 240.208 Residue....

  6. 40 CFR 240.208 - Residue.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Residue. 240.208 Section 240.208 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES GUIDELINES FOR THE THERMAL PROCESSING OF SOLID WASTES Requirements and Recommended Procedures § 240.208 Residue....

  7. Residuals Management and Water Pollution Control Planning.

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Washington, DC. Office of Public Affairs.

    This pamphlet addresses the problems associated with residuals and water quality especially as it relates to the National Water Pollution Control Program. The types of residuals and appropriate management systems are discussed. Additionally, one section is devoted to the role of citizen participation in developing management programs. (CS)

  8. Soil water evaporation and crop residues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop residues have value when left in the field and also when removed from the field and sold as a commodity. Reducing soil water evaporation (E) is one of the benefits of leaving crop residues in place. E was measured beneath a corn canopy at the soil suface with nearly full coverage by corn stover...

  9. Measurment Of Residual Stress In Ferromagnetic Materials

    NASA Technical Reports Server (NTRS)

    Namkung, Min; Yost, William T.; Kushnick, Peter W.; Grainger, John L.

    1992-01-01

    Magnetoacoustic (MAC) and magnetoacoustic emission (MAE) techniques combined to provide complete characterization of residual stresses in ferromagnetic structural materials. Combination of MAC and MAE techniques makes it possible to characterize residual tension and compression without being limited by surface conditions and unavailability of calibration standards. Significant in field of characterization of materials as well as detection of fatigue failure.

  10. THE IMMIGRANT POOR AND THE RESIDUAL POOR.

    ERIC Educational Resources Information Center

    SEGALMAN, RALPH

    AN ANALYSIS OF THE LIVES OF THE POOR IN AMERICA WILL SHOW DIFFERENCES BETWEEN THE IMMIGRANT (AND REFUGEE) POOR AND THE RESIDUAL POOR (NEGROES, PUERTO RICANS, LATIN AMERICANS, INDIANS, AND OTHERS). THE IMMIGRANT POOR WERE ACCULTURATED AND ABSORBED INTO THE MAINSTREAM OF AMERICAN LIFE WITHIN THREE GENERATIONS, WHEREAS THE RESIDUAL POOR HAVE BEEN…

  11. 9 CFR 311.39 - Biological residues.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Biological residues. 311.39 Section 311.39 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE... Biological residues. Carcasses, organs, or other parts of carcasses of livestock shall be condemned if it...

  12. Unicystic ameloblastoma arising from a residual cyst

    PubMed Central

    Mahajan, Amit D; Manjunatha, Bhari Sharanesha; Khurana, Neha M; Shah, Navin

    2014-01-01

    Intraoral swellings involving alveolar ridges in edentulous patients are clinically diagnosed as residual cysts, traumatic bone cysts, Stafne's jaw bone cavity, ameloblastoma and metastatic tumours of the jaw. This case report describes a residual cyst in a 68-year-old edentulous male patient which was enucleated and histopathologically confirmed as a unicystic ameloblastoma. PMID:25199192

  13. 48 CFR 1450.104 - Residual powers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Residual powers. 1450.104 Section 1450.104 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR CONTRACT MANAGEMENT EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 1450.104 Residual powers....

  14. 48 CFR 1450.104 - Residual powers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Residual powers. 1450.104 Section 1450.104 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR CONTRACT MANAGEMENT EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 1450.104 Residual powers....

  15. 48 CFR 1450.104 - Residual powers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Residual powers. 1450.104 Section 1450.104 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR CONTRACT MANAGEMENT EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 1450.104 Residual powers....

  16. 48 CFR 1450.104 - Residual powers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Residual powers. 1450.104 Section 1450.104 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR CONTRACT MANAGEMENT EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 1450.104 Residual powers....

  17. Tank 12H residuals sample analysis report

    SciTech Connect

    Oji, L. N.; Shine, E. P.; Diprete, D. P.; Coleman, C. J.; Hay, M. S.

    2015-06-11

    The Savannah River National Laboratory (SRNL) was requested by Savannah River Remediation (SRR) to provide sample preparation and analysis of the Tank 12H final characterization samples to determine the residual tank inventory prior to grouting. Eleven Tank 12H floor and mound residual material samples and three cooling coil scrape samples were collected and delivered to SRNL between May and August of 2014.

  18. RECOVERY OF URANIUM VALUES FROM RESIDUES

    DOEpatents

    Schaap, W.B.

    1959-08-18

    A process is described for the recovery of uranium from insoluble oxide residues resistant to repeated leaching with mineral acids. The residue is treated with gaseous hydrogen fluoride, then with hydrogen and again with hydrogen fluoride, preferably at 500 to 700 deg C, prior to the mineral acid leaching.

  19. Residuals and the Residual-Based Statistic for Testing Goodness of Fit of Structural Equation Models

    ERIC Educational Resources Information Center

    Foldnes, Njal; Foss, Tron; Olsson, Ulf Henning

    2012-01-01

    The residuals obtained from fitting a structural equation model are crucial ingredients in obtaining chi-square goodness-of-fit statistics for the model. The authors present a didactic discussion of the residuals, obtaining a geometrical interpretation by recognizing the residuals as the result of oblique projections. This sheds light on the…

  20. High-quality CdTe films from nanoparticle precursors

    SciTech Connect

    Schulz, D.L.; Pehnt, M.; Urgiles, E.

    1996-05-01

    In this paper the authors demonstrate that nanoparticulate precursors coupled with spray deposition offers an attractive route into electronic materials with improved smoothness, density, and lower processing temperatures. Employing a metathesis approach, cadmium iodide was reacted with sodium telluride in methanol solvent, resulting in the formation of soluble NaI and insoluble CdTe nanoparticles. After appropriate chemical workup, methanol-capped CdTe colloids were isolated. CdTe thin film formation was achieved by spray depositing the nanoparticle colloids (25-75 {Angstrom} diameter) onto substrates at elevated temperatures (T = 280-440{degrees}C) with no further thermal treatment. These films were characterized by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Cubic CdTe phase formation was observed by XRD, with a contaminant oxide phase also detected. XPS analysis showed that CdTe films produced by this one-step method contained no Na or C and substantial O. AFM gave CdTe grain sizes of {approx}0.1-0.3 {mu}m for film sprayed at 400{degrees}C. A layer-by-layer film growth mechanism proposed for the one-step spray deposition of nanoparticle precursors will be discussed.