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Sample records for acid aa cascade

  1. Lithium and the other mood stabilizers effective in bipolar disorder target the rat brain arachidonic acid cascade.

    PubMed

    Rapoport, Stanley I

    2014-06-18

    This Review evaluates the arachidonic acid (AA, 20:4n-6) cascade hypothesis for the actions of lithium and other FDA-approved mood stabilizers in bipolar disorder (BD). The hypothesis is based on evidence in unanesthetized rats that chronically administered lithium, carbamazepine, valproate, or lamotrigine each downregulated brain AA metabolism, and it is consistent with reported upregulated AA cascade markers in post-mortem BD brain. In the rats, each mood stabilizer reduced AA turnover in brain phospholipids, cyclooxygenase-2 expression, and prostaglandin E2 concentration. Lithium and carbamazepine also reduced expression of cytosolic phospholipase A2 (cPLA2) IVA, which releases AA from membrane phospholipids, whereas valproate uncompetitively inhibited in vitro acyl-CoA synthetase-4, which recycles AA into phospholipid. Topiramate and gabapentin, proven ineffective in BD, changed rat brain AA metabolism minimally. On the other hand, the atypical antipsychotics olanzapine and clozapine, which show efficacy in BD, decreased rat brain AA metabolism by reducing plasma AA availability. Each of the four approved mood stabilizers also dampened brain AA signaling during glutamatergic NMDA and dopaminergic D2 receptor activation, while lithium enhanced the signal during cholinergic muscarinic receptor activation. In BD patients, such signaling effects might normalize the neurotransmission imbalance proposed to cause disease symptoms. Additionally, the antidepressants fluoxetine and imipramine, which tend to switch BD depression to mania, each increased AA turnover and cPLA2 IVA expression in rat brain, suggesting that brain AA metabolism is higher in BD mania than depression. The AA hypothesis for mood stabilizer action is consistent with reports that low-dose aspirin reduced morbidity in patients taking lithium, and that high n-3 and/or low n-6 polyunsaturated fatty acid diets, which in rats reduce brain AA metabolism, were effective in BD and migraine patients. PMID

  2. Ascorbic acid (AA) metabolism in protection against radiation damage

    SciTech Connect

    Rose, R.C.; Koch, M.J.

    1986-03-05

    The possibility is considered that AA protects tissues against radiation damage by scavenging free radicals that result from radiolysis of water. A physiologic buffer (pH 6.7) was incubated with /sup 14/C-AA and 1 mM thiourea (to slow spontaneous oxidation of AA). Aliquots were assayed by HPLC and scintillation spectrometry to identify the /sup 14/C-label. Samples exposed to Cobalt-60 radiation had a half time of AA decay of < 3 minutes compared with nonirradiated samples (t/sub 1/2/ > 30 minutes) indicating that AA scavenges radiation-induced free radicals and forms the ascorbate free radical (AFR). Pairs of /sup 14/C-AFR disproportionate, with the net effect of /sup 14/C-dehydroascorbic acid formation from /sup 14/C-AA. Having established that AFR result from ionizing radiation in an aqueous solution, the possibility was evaluated that a tissue factor reduces AFR. Cortical tissue from the kidneys of male rats was minced, homogenized in buffer and centrifuged at 8000 xg. The supernatant was found to slow the rate of radiation-induced AA degradation by > 90% when incubated at 23/sup 0/C in the presence of 15 ..mu..M /sup 14/C-AA. Samples of supernatant maintained at 100/sup 0/C for 10 minutes or precipitated with 5% PCA did not prevent radiation-induced AA degradation. AA may have a specific role in scavenging free radicals generated by ionizing radiation and thereby protect body tissues.

  3. Intrauterine, postpartum and adult relationships between arachidonic acid (AA) and docosahexaenoic acid (DHA).

    PubMed

    Kuipers, Remko S; Luxwolda, Martine F; Janneke Dijck-Brouwer, D A; Muskiet, Frits A J

    2011-11-01

    Erythrocyte (RBC) fatty acid compositions from populations with stable dietary habits but large variations in RBC-arachidonic (AA) and RBC-docosahexaenoic acid (DHA) provided us with insight into relationships between DHA and AA. It also enabled us to estimate the maternal RBC-DHA (mRBC-DHA) status that corresponded with no decrease in mRBC-DHA during pregnancy, or in infant (i) RBC-DHA or mRBC-DHA during the first 3 months postpartum (DHA-equilibrium) while exclusively breastfeeding. At delivery, iRBC-AA is uniformly high and independent of mRBC-AA. Infants born to mothers with low RBC-DHA exhibit higher, but infants born to mothers with high RBC-DHA exhibit lower RBC-DHA than their mothers. This switch from 'biomagnification' into 'bioattenuation' occurs at 6g% mRBC-DHA. At 6g%, mRBC-DHA is stable throughout pregnancy, corresponds with postpartum infant DHA-equilibrium of 6 and 0.4g% DHA in mature milk, but results in postpartum depletion of mRBC-DHA to 5g%. Postpartum maternal DHA-equilibrium is reached at 8g% mRBC-DHA, corresponding with 1g% DHA in mature milk and 7g% iRBC-DHA at delivery that increases to 8g% during lactation. This 8g% RBC-DHA concurs with the lowest risks of cardiovascular and psychiatric diseases in adults. RBC-data from 1866 infants, males and (non-)pregnant females indicated AA vs. DHA synergism at low RBC-DHA, but antagonism at high RBC-DHA. These data, together with high intakes of AA and DHA from our Paleolithic diet, suggest that bioattenuation of DHA during pregnancy and postnatal antagonism between AA and DHA are the physiological standard for humans across the life cycle. PMID:21561751

  4. Targeted metabolomics of the arachidonic acid cascade: current state and challenges of LC-MS analysis of oxylipins.

    PubMed

    Willenberg, Ina; Ostermann, Annika I; Schebb, Nils Helge

    2015-04-01

    Quantification of eicosanoids and oxylipins derived from other polyunsaturated fatty acids in biological samples is crucial for a better understanding of the biology of these lipid mediators. Moreover, a robust and reliable quantification is necessary to monitor the effects of pharmaceutical intervention and diet on the arachidonic acid (AA) cascade, one of today's most relevant drug targets. Low (sub-nanomolar) concentrations and a large number of structurally similar analytes, including regioisomers, require high chromatographic resolution and selective and sensitive mass spectrometry analysis. Currently, reversed-phase liquid chromatography in combination with detection on sensitive triple-quadrupole instruments, operating in selected reaction monitoring mode, is the main method of quantitative oxylipin analysis. A lack of standardized sample collection, handling, and preparation procedures, degradation of the analytes during sample preparation, and purity and availability of standards (internal standards) are the major problems of targeted metabolomics approaches for the AA cascade. Major challenges for instrumental analytical methods are the detection of esterified oxylipins, and separation and individual detection of oxylipin isomers. Solving these problems would help to further knowledge of the biology of lipid mediators, and is an important task for bio-analytical research. PMID:25577350

  5. Oxygenation by COX-2 (cyclo-oxygenase-2) of 3-HETE (3-hydroxyeicosatetraenoic acid), a fungal mimetic of arachidonic acid, produces a cascade of novel bioactive 3-hydroxyeicosanoids

    PubMed Central

    2005-01-01

    Cyclo-oxygenases-1/2 (COX-1/2) catalyse the oxygenation of AA (arachidonic acid) and related polyunsaturated fatty acids to endoperoxide precursors of prostanoids. COX-1 is referred to as a constitutive enzyme involved in haemostasis, whereas COX-2 is an inducible enzyme expressed in inflammatory diseases and cancer. The fungus Dipodascopsis uninucleata has been shown by us to convert exogenous AA into 3(R)-HETE [3(R)-hydroxy-5Z,8Z,11Z,14Z-eicosatetraenoic acid]. 3R-HETE is stereochemically identical with AA, except that a hydroxy group is attached at its C-3 position. Molecular modelling studies with 3-HETE and COX-1/2 revealed a similar enzyme–substrate structure as reported for AA and COX-1/2. Here, we report that 3-HETE is an appropriate substrate for COX-1 and -2, albeit with a lower activity of oxygenation than AA. Oxygenation of 3-HETE by COX-2 produced a novel cascade of 3-hydroxyeicosanoids, as identified with EI (electron impact)–GC–MS, LC–MS–ES (electrospray) and LC–MS–API (atmospheric pressure ionization) methods. Evidence for in vitro production of 3-hydroxy-PGE2 (3-hydroxy-prostaglandin E2) was obtained upon infection of HeLa cells with Candida albicans at an MOI (multiplicity of infection) of 100. Analogous to interaction of AA and aspirin-treated COX-2, 3-HETE was transformed by acetylated COX-2 to 3,15-di-HETE (3,15-dihydroxy-HETE), whereby C-15 showed the (R)-stereochemistry. 3-Hydroxy-PGs are potent biologically active compounds. Thus 3-hydroxy-PGE2 induced interleukin-6 gene expression via the EP3 receptor (PGE2 receptor 3) in A549 cells, and raised cAMP levels via the EP4 receptor in Jurkat cells. Moreover, 3R,15S-di-HETE triggered the opening of the K+ channel in HTM (human trabecular meshwork) cells, as measured by the patch–clamp technique. Since many fatty acid disorders are associated with an ‘escape’ of 3-hydroxy fatty acids from the β-oxidation cycle, the production of 3-hydroxyeicosanoids may be critical in

  6. Omega-3 PUFAs Lower the Propensity for Arachidonic Acid Cascade Overreactions

    PubMed Central

    Lands, Bill

    2015-01-01

    A productive view of the benefits from omega-3 (n-3) nutrients is that the dietary essential omega-6 (n-6) linoleic acid has a very narrow therapeutic window which is widened by n-3 nutrients. The benefit from moderate physiological actions of the arachidonic acid cascade can easily shift to harm from excessive pathophysiological actions. Recognizing the factors that predispose the cascade to an unwanted overactivity gives a rational approach for arranging beneficial interactions between the n-3 and n-6 essential nutrients that are initial components of the cascade. Much detailed evidence for harmful cascade actions was collected by pharmaceutical companies as they developed drugs to decrease those actions. A remaining challenge is to understand the factors that predispose the cascade toward unwanted outcomes and create the need for therapeutic interventions. Such understanding involves recognizing the similar dynamics for dietary n-3 and n-6 nutrients in forming the immediate precursors of the cascade plus the more vigorous actions of the n-6 precursor, arachidonic acid, in forming potent mediators that amplify unwanted cascade outcomes. Tools have been developed to aid deliberate day-to-day quantitative management of the propensity for cascade overactivity in ways that can decrease the need for drug treatments. PMID:26301244

  7. Performance of AA5052 alloy anode in alkaline ethylene glycol electrolyte with dicarboxylic acids additives for aluminium-air batteries

    NASA Astrophysics Data System (ADS)

    Wang, DaPeng; Zhang, DaQuan; Lee, KangYong; Gao, LiXin

    2015-11-01

    Dicarboxylic acid compounds, i.e. succinic acid (SUA), adipic acid (ADA) and sebacic acid (SEA), are used as electrolyte additives in the alkaline ethylene glycol solution for AA5052 aluminium-air batteries. It shows that the addition of dicarboxylic acids lowers the hydrogen gas evolution rate of commercial AA5052 aluminium alloy anode. AA5052 aluminium alloy has wide potential window for electrochemical activity and better discharge performance in alkaline ethylene glycol solution containing dicarboxylic acid additives. ADA has the best inhibition effect for the self-corrosion of AA5052 anode among the three dicarboxylic acid additives. Fourier transform infrared spectroscopy (FT-IR) reveals that dicarboxylic acids and aluminium ions can form coordination complexes. Quantum chemical calculations shows that ADA has a smaller energy gap (ΔE, the energy difference between the lowest unoccupied orbital and the highest occupied orbital), indicating that ADA has the strongest interaction with aluminium ions.

  8. AA-PMe, a novel asiatic acid derivative, induces apoptosis and suppresses proliferation, migration, and invasion of gastric cancer cells.

    PubMed

    Jing, Yue; Wang, Gang; Ge, Ying; Xu, Minjie; Tang, Shuainan; Gong, Zhunan

    2016-01-01

    Asiatic acid (AA; 2α,3β,23-trihydroxyurs-12-ene-28-oic acid) is widely used for medicinal purposes in many Asian countries due to its various bioactivities. A series of AA derivatives has been synthesized in attempts to improve its therapeutic potencies. Herein we investigated the anti-tumor activities of N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-l-proline methyl ester (AA-PMe), a novel AA derivative. AA-PMe exhibited a stronger anti-cancer activity than its parent compound AA. AA-PMe inhibited the proliferation of SGC7901 and HGC27 human gastric cancer cells in a dose-dependent manner but had no significant toxicity in human gastric mucosa epithelial cells (GES-1). AA-PMe induced cell cycle arrest in G0/G1 phase and blocked G1-S transition, which correlated well with marked decreases in levels of cyclin D1, cyclin-dependent kinase CKD4, and phosphorylated retinoblastoma protein, and increase in cyclin-dependent kinase inhibitor P15. Further, AA-PMe induced apoptosis of human gastric cancer cells by affecting Bcl-2, Bax, c-Myc, and caspase-3. Moreover, AA-PMe suppressed the migration and invasion of human gastric cancer cells (SGC7901 and HGC27) cells by downregulating the expression of MMP-2 and MMP-9. Overall, this study investigated the potential anti-cancer activities of AA-PMe including inducing apoptosis and suppressing proliferation, migration and invasion of gastric cancer cells, as well as the underlying mechanisms, suggesting that AA-PMe is a promising anti-cancer drug candidate in gastric cancer therapy. PMID:27073325

  9. AA-PMe, a novel asiatic acid derivative, induces apoptosis and suppresses proliferation, migration, and invasion of gastric cancer cells

    PubMed Central

    Jing, Yue; Wang, Gang; Ge, Ying; Xu, Minjie; Tang, Shuainan; Gong, Zhunan

    2016-01-01

    Asiatic acid (AA; 2α,3β,23-trihydroxyurs-12-ene-28-oic acid) is widely used for medicinal purposes in many Asian countries due to its various bioactivities. A series of AA derivatives has been synthesized in attempts to improve its therapeutic potencies. Herein we investigated the anti-tumor activities of N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-l-proline methyl ester (AA-PMe), a novel AA derivative. AA-PMe exhibited a stronger anti-cancer activity than its parent compound AA. AA-PMe inhibited the proliferation of SGC7901 and HGC27 human gastric cancer cells in a dose-dependent manner but had no significant toxicity in human gastric mucosa epithelial cells (GES-1). AA-PMe induced cell cycle arrest in G0/G1 phase and blocked G1-S transition, which correlated well with marked decreases in levels of cyclin D1, cyclin-dependent kinase CKD4, and phosphorylated retinoblastoma protein, and increase in cyclin-dependent kinase inhibitor P15. Further, AA-PMe induced apoptosis of human gastric cancer cells by affecting Bcl-2, Bax, c-Myc, and caspase-3. Moreover, AA-PMe suppressed the migration and invasion of human gastric cancer cells (SGC7901 and HGC27) cells by downregulating the expression of MMP-2 and MMP-9. Overall, this study investigated the potential anti-cancer activities of AA-PMe including inducing apoptosis and suppressing proliferation, migration and invasion of gastric cancer cells, as well as the underlying mechanisms, suggesting that AA-PMe is a promising anti-cancer drug candidate in gastric cancer therapy. PMID:27073325

  10. Powerful Amplification Cascades of FRET-Based Two-Layer Nonenzymatic Nucleic Acid Circuits.

    PubMed

    Quan, Ke; Huang, Jin; Yang, Xiaohai; Yang, Yanjing; Ying, Le; Wang, He; Xie, Nuli; Ou, Min; Wang, Kemin

    2016-06-01

    Nucleic acid circuits have played important roles in biological engineering and have increasingly attracted researchers' attention. They are primarily based on nucleic acid hybridizations and strand displacement reactions between nucleic acid probes of different lengths. Signal amplification schemes that do not rely on protein enzyme show great potential in analytical applications. While the single amplification circuit often achieves linear amplification that may not meet the need for detection of target in a very small amount, it is very necessary to construct cascade circuits that allow for larger amplification of inputs. Herein, we have successfully engineered powerful amplification cascades of FRET-based two-layer nonenzymatic nucleic acid circuits, in which the outputs of catalyzed hairpin assembly (CHA) activate hybridization chain reactions (HCR) circuits to induce repeated hybridization, allowing real-time monitoring of self-assembly process by FRET signal. The cascades can yield 50000-fold signal amplification with the help of the well-designed and high-quality nucleic acid circuit amplifiers. Subsequently, with coupling of structure-switching aptamer, as low as 200 pM adenosine is detected in buffer, as well as in human serum. To our knowledge, we have for the first time realized real-time monitoring adaptation of HCR to CHA circuits and achieved amplified detection of nucleic acids and small molecules with relatively high sensitivity. PMID:27142084

  11. Lactic acid fermentation within a cascading approach for biowaste treatment.

    PubMed

    Probst, Maraike; Walde, Janette; Pümpel, Thomas; Wagner, Andreas Otto; Schneider, Irene; Insam, Heribert

    2015-04-01

    Limited availability of resources and increased amounts of waste coupled with an ever-increasing demand for raw materials are typical characteristics of our times. As such, there is an urgent need to accordingly update waste treatment technology. The aim of this study was to determine whether a separate treatment of the liquid and the solid fraction of biowaste could enhance overall efficiency. Liquid fractions obtained from two different separation procedures were fermented at a pH of 5 and uncontrolled pH conditions for 72 h. The fermentation conditions leading to highest lactic acid productivity and yield were evaluated. The substrates gained by both separation procedures showed efficient lactic acid production up to <25 g L(-1). The pH control increased lactic acid concentration by about 27 %. Furthermore, quantitative real-time PCR analyses revealed stronger Lactobacilli growth in these fermentations. As identified via Illumina sequencing Lactobacillus delbrueckii and its closest relatives seemed to drive the fermentation independent of the substrate. These results could help to improve today's resourcing concept by providing a separate treatment of the liquid and solid biowaste fraction. PMID:25652656

  12. Decrypting the H-NS-dependent regulatory cascade of acid stress resistance in Escherichia coli

    PubMed Central

    2010-01-01

    Background H-NS regulates the acid stress resistance. The present study aimed to characterize the H-NS-dependent cascade governing the acid stress resistance pathways and to define the interplay between the different regulators. Results We combined mutational, phenotypic and gene expression analyses, to unravel the regulatory hierarchy in acid resistance involving H-NS, RcsB-P/GadE complex, HdfR, CadC, AdiY regulators, and DNA-binding assays to separate direct effects from indirect ones. RcsB-P/GadE regulatory complex, the general direct regulator of glutamate-, arginine- and lysine-dependent acid resistance pathways plays a central role in the regulatory cascade. However, H-NS also directly controls specific regulators of these pathways (e.g. cadC) and genes involved in general stress resistance (hdeAB, hdeD, dps, adiY). Finally, we found that in addition to H-NS and RcsB, a third regulator, HdfR, inversely controls glutamate-dependent acid resistance pathway and motility. Conclusions H-NS lies near the top of the hierarchy orchestrating acid response centred on RcsB-P/GadE regulatory complex, the general direct regulator of glutamate-, arginine- and lysine-dependent acid resistance pathways. PMID:21034467

  13. A Multi-Enzymatic Cascade Reaction for the Stereoselective Production of γ-Oxyfunctionalyzed Amino Acids.

    PubMed

    Enoki, Junichi; Meisborn, Jaqueline; Müller, Ann-Christin; Kourist, Robert

    2016-01-01

    A stereoselective three-enzyme cascade for synthesis of diasteromerically pure γ-oxyfunctionalized α-amino acids was developed. By coupling a dynamic kinetic resolution (DKR) using an N-acylamino acid racemase (NAAAR) and an L-selective aminoacylase from Geobacillus thermoglucosidasius with a stereoselective isoleucine dioxygenase from Bacillus thuringiensis, diastereomerically pure oxidized amino acids were produced from racemic N-acetylamino acids. The three enzymes differed in their optimal temperature and pH-spectra. Their different metal cofactor dependencies led to inhibitory effects. Under optimized conditions, racemic N-acetylmethionine was quantitatively converted into L-methionine-(S)-sulfoxide with 97% yield and 95% de. The combination of these three different biocatalysts allowed the direct synthesis of diastereopure oxyfunctionalized amino acids from inexpensive racemic starting material. PMID:27092111

  14. A Multi-Enzymatic Cascade Reaction for the Stereoselective Production of γ-Oxyfunctionalyzed Amino Acids

    PubMed Central

    Enoki, Junichi; Meisborn, Jaqueline; Müller, Ann-Christin; Kourist, Robert

    2016-01-01

    A stereoselective three-enzyme cascade for synthesis of diasteromerically pure γ-oxyfunctionalized α-amino acids was developed. By coupling a dynamic kinetic resolution (DKR) using an N-acylamino acid racemase (NAAAR) and an L-selective aminoacylase from Geobacillus thermoglucosidasius with a stereoselective isoleucine dioxygenase from Bacillus thuringiensis, diastereomerically pure oxidized amino acids were produced from racemic N-acetylamino acids. The three enzymes differed in their optimal temperature and pH-spectra. Their different metal cofactor dependencies led to inhibitory effects. Under optimized conditions, racemic N-acetylmethionine was quantitatively converted into L-methionine-(S)-sulfoxide with 97% yield and 95% de. The combination of these three different biocatalysts allowed the direct synthesis of diastereopure oxyfunctionalized amino acids from inexpensive racemic starting material. PMID:27092111

  15. Ascorbic acid suppresses endotoxemia and NF-κB signaling cascade in alcoholic liver fibrosis in guinea pigs: A mechanistic approach

    SciTech Connect

    Abhilash, P.A.; Harikrishnan, R.; Indira, M.

    2014-01-15

    Alcohol consumption increases the small intestinal bacterial overgrowth (SIBO) and intestinal permeability of endotoxin. The endotoxin mediated inflammatory signaling plays a major role in alcoholic liver fibrosis. We evaluated the effect of ascorbic acid (AA), silymarin and alcohol abstention on the alcohol induced endotoxemia and NF-κB activation cascade pathway in guinea pigs (Cavia porcellus). Guinea pigs were administered ethanol at a daily dose of 4 g/kg b.wt for 90 days. After 90 days, ethanol administration was stopped. The ethanol treated animals were divided into abstention, silymarin (250 mg/kg b.wt) and AA (250 mg/kg b.wt) supplemented groups and maintained for 30 days. The SIBO, intestinal permeability and endotoxin were significantly increased in the ethanol group. The mRNA expressions of intestinal proteins claudin, occludin and zona occludens-1 were significantly decreased in ethanol group. The mRNA levels of inflammatory receptors, activity of IKKβ and the protein expressions of phospho-IκBα, NF-κB, TNF-α, TGF-β{sub 1} and IL-6 were also altered in ethanol group. The expressions of fibrosis markers α-SMA, α{sub 1} (I) collagen and sirius red staining in the liver revealed the induction of fibrosis. But the supplementation of AA could induce greater reduction of ethanol induced SIBO, intestinal barrier defects, NF-κB activation and liver fibrosis than silymarin. The possible mechanism may be the inhibitory effect of AA on SIBO, intestinal barrier defect and IKKβ, which decreased the activation of NF-κB and synthesis of cytokines. This might have led to suppression of HSCs activation and liver fibrosis. - Highlights: • Alcohol increases intestinal bacterial overgrowth and permeability of endotoxin. • Endotoxin mediated inflammation plays a major role in alcoholic liver fibrosis. • Ascorbic acid reduces endotoxemia, NF-κB activation and proinflammatory cytokines. • AA's action is by inhibition of SIBO, IKKβ and alteration of

  16. Synergism and Rules of the new Combination drug Yiqijiedu Formulae (YQJD) on Ischemic Stroke based on amino acids (AAs) metabolism

    PubMed Central

    Gao, Jian; Chen, Chang; Chen, Jian-Xin; Wen, Li-Mei; Yang, Geng-Liang; Duan, Fei-Peng; Huang, Zhi-Ying; Li, De-Feng; Yu, Ding-Rong; Yang, Hong-Jun; Li, Shao-Jing

    2014-01-01

    The use of combination drugs is considered to be a promising strategy to control complex diseases such as ischemic stroke. The detection of metabolites has been used as a versatile tool to reveal the potential mechanism of diverse diseases. In this study, the levels of 12 endogenous AAs were simultaneously determined quantitatively in the MCAO rat brain using RRLC-QQQ method. Seven AAs were chosen as the potential biomarkers, and using PLS-DA analysis, the effects of the new combination drug YQJD, which is composed of ginsenosides, berberine, and jasminoidin, on those 7 AAs were evaluated. Four AAs, glutamic acid, homocysteine, methionine, and tryptophan, which changed significantly in the YQJD-treated groups compared to the vehicle groups (P < 0.05), were identified and designated as the AAs to use to further explore the synergism of YQJD. The result of a PCA showed that the combination of these three drugs exhibits the strongest synergistic effect compared to other combination groups and that ginsenosides might play a pivotal role, especially when combined with jasminoidin. We successfully explored the synergetic mechanism of multi-component and provided a new method for evaluating the integrated effects of combination drugs in the treatment of complex diseases. PMID:24889025

  17. Periodontal disease: modulation of the inflammatory cascade by dietary n-3 polyunsaturated fatty acids.

    PubMed

    Sculley, D V

    2014-06-01

    Periodontal disease, including gingivitis and periodontitis, is caused by the interaction between pathogenic bacteria and the host immune system. The ensuing oxidative stress and inflammatory cascade result in the destruction of gingival tissue, alveolar bone and periodontal ligament. This article reviews the underlying mechanisms and host-bacteria interactions responsible for periodontal disease and evidence that nutritional supplementation with fish oil may provide a protective effect. Historical investigations of diet and disease have highlighted an inverse relationship between ingestion of fish oil, which is high in n-3 polyunsaturated fatty acids, and the incidence of typical inflammatory diseases such as arthritis and coronary heart disease. Ingestion of n-3 polyunsaturated fatty acids, such as docosahexaenoic acid and eicosapentaenoic acid, results in their incorporation into membrane phospholipids, which can alter eicosanoid production after stimulation during the immune response. These eicosanoids promote a reduction in chronic inflammation, which has led to the proposal that fish oil is a possible modulator of inflammation and may reduce the severity of periodontal diseases. Tentative animal and human studies have provided an indication of this effect. Further human investigation is needed to establish the protective effects of fish oil in relation to periodontal disease. PMID:23889472

  18. Titania-Promoted Carboxylic Acid Alkylations of Alkenes and Cascade Addition–Cyclizations

    PubMed Central

    2014-01-01

    Photochemical reactions employing TiO2 and carboxylic acids under dry anaerobic conditions led to several types of C–C bond-forming processes with electron-deficient alkenes. The efficiency of alkylation varied appreciably with substituents in the carboxylic acids. The reactions of aryloxyacetic acids with maleimides resulted in a cascade process in which a pyrrolochromene derivative accompanied the alkylated succinimide. The selectivity for one or other of these products could be tuned to some extent by employing the photoredox catalyst under different conditions. Aryloxyacetic acids adapted for intramolecular ring closures by inclusion of 2-alkenyl, 2-aryl, or 2-oximinyl functionality reacted rather poorly. Profiles of reactant consumption and product formation for these systems were obtained by an in situ NMR monitoring technique. An array of different catalyst forms were tested for efficiency and ease of use. The proposed mechanism, involving hole capture at the TiO2 surface by the carboxylates followed by CO2 loss, was supported by EPR spectroscopic evidence of the intermediates. Deuterium labeling indicated that the titania likely donates protons from surface hydroxyl groups as well as supplying electrons and holes, thus acting as both a catalyst and a reaction partner. PMID:24437519

  19. Cascade enzymatic catalysis in poly(acrylic acid) brushes-nanospherical silica for glucose detection.

    PubMed

    Zhao, Yan; Wang, Ying; Zhang, Xiaobin; Kong, Rongmei; Xia, Lian; Qu, Fengli

    2016-08-01

    The ultrasensitive monitoring of glucose with a fast and accurate method is significant in potential therapeutics and optimizes protein biosynthesis. Incorporation of enzyme into matrix is considered as promising candidates for constructing highly sensitive glucose-responsive systems. In this study, three-dimensional poly(acrylic acid) brushes-nanospherical silica (PAA-nano silica) with high amplification capability and stability were used to covalently immobilize bienzymes for cascade enzymatic catalysis. The major advantages of PAA-nano silica-bienzyme co-incorporation is that the enzymes are proximity distribution, and such close confinement both minimized the diffusion of intermediates among the enzymes in the consecutive reaction and improve the utilization efficiency of enzymes, thereby enhancing the overall reaction efficiency and specificity. Thus, this present bienzymatic biosensor shows robust signal amplification and ultrasensitivity of glucose-responsive properties with a detection limit of 0.04μM. PMID:27216683

  20. Megranate-like nanoreactor with multiple cores and an acidic mesoporous shell for a cascade reaction

    NASA Astrophysics Data System (ADS)

    Wang, Xue; Guan, Buyuan; He, Yapeng; An, Dong; Zhang, Ye; Cao, Yu; Li, Xiang; Liu, Yunling; Huo, Qisheng

    2015-02-01

    Megranate-like nanoparticles possess a unique structure that is composed of multiple cores and shells, which is different from simple yolk-shell nanoparticles. Megranate-like nanoparticles can combine the properties of each component and be used as nanoreactors. This study describes the preparation of bifunctional megranate-like nanoreactors, consisting of multiple metal cores and thiol modified mesoporous SiO2 shells. Different metal nanoparticles (Pd, Pt, Au) can be incorporated into the structure as cores, and the thiol group in the shells can be oxidized to acidic -SO3H. The megranate-like nanoparticles show good bifunctional catalytic properties and recyclability in a cascade catalytic reaction for the desired benzimidazole derivative. Moreover, the individual components of the megranate-like nanoparticles also show good catalytic activities in the hydrogenation reduction of nitro-aromatics and the deprotection reaction of benzaldehyde dimethyl acetal.Megranate-like nanoparticles possess a unique structure that is composed of multiple cores and shells, which is different from simple yolk-shell nanoparticles. Megranate-like nanoparticles can combine the properties of each component and be used as nanoreactors. This study describes the preparation of bifunctional megranate-like nanoreactors, consisting of multiple metal cores and thiol modified mesoporous SiO2 shells. Different metal nanoparticles (Pd, Pt, Au) can be incorporated into the structure as cores, and the thiol group in the shells can be oxidized to acidic -SO3H. The megranate-like nanoparticles show good bifunctional catalytic properties and recyclability in a cascade catalytic reaction for the desired benzimidazole derivative. Moreover, the individual components of the megranate-like nanoparticles also show good catalytic activities in the hydrogenation reduction of nitro-aromatics and the deprotection reaction of benzaldehyde dimethyl acetal. Electronic supplementary information (ESI) available

  1. The combined impact of plant-derived dietary ingredients and acute stress on the intestinal arachidonic acid cascade in Atlantic salmon (Salmo salar).

    PubMed

    Oxley, Anthony; Jolly, Cecile; Eide, Torunn; Jordal, Ann-Elise O; Svardal, Asbjørn; Olsen, Rolf-Erik

    2010-03-01

    A study was conducted to assess the effect of substituting high levels of dietary fish oil (FO) and fishmeal (FM) for vegetable oil (VO) and plant protein (PP) on the intestinal arachidonic acid (AA) cascade in the carnivorous fish species Atlantic salmon. Four diets were fed to salmon over a period of 12 months, including a control FMFO diet, with varying replacements of plant-derived ingredients: 80 % PP and 35 % VO; 40 % PP and 70 % VO; 80 % PP and 70 %VO. Subsequently, fish were examined pre- (0 h) and post- (1 h) acute stress for blood parameters and intestinal bioactive lipidic mediators of inflammation (prostaglandins). Plasma cortisol responses were greatest in the FMFO group, while 80 % PP and 70 % VO fish exhibited increased plasma chloride concentrations. The n-3:n-6 PUFA ratio in intestinal glycerophospholipids from 70 % VO groups significantly decreased in both proximal and distal regions due to elevated levels of 18 : 2n-6 and the elongation/desaturation products 20 : 2n-6 and 20 : 3n-6. Increases in n-6 PUFA were not concomitant with increased AA, although the AA:EPA ratio did vary significantly. The 40 % PP and 70 % VO diet produced the highest intestinal AA:EPA ratio proximally, which coincided with a trend in elevated levels of PGF2alpha, PGE2 and 6-keto-PGF1alpha in response to stress. PGE2 predominated over PGF2alpha and 6-keto-PGF1alpha (stable metabolite of PGI2) with comparable concentrations in both intestinal regions. Cyclo-oxygenase-2 (COX-2) mRNA expression was an order of magnitude higher in distal intestine, compared with proximal, and was significantly up-regulated following stress. Furthermore, the 80 % PP and 70 % VO diet significantly amplified proximal COX-2 induction post-stress. Results demonstrate that high replacements with plant-derived dietary ingredients can enhance COX-2 induction and synthesis of pro-inflammatory eicosanoids in the intestine of salmon in response to acute physiological stress. PMID:19943982

  2. Energy driven cascade recognition for selective detection of nucleic acids with high discrimination factor at room temperature.

    PubMed

    Zhang, Zhang; Li, Jun Long; Yao, Juan; Wang, Ting; Yin, Dan; Xiang, Yu; Chen, Zhongping; Xie, Guoming

    2016-05-15

    In this article, we demonstrated a cascade recognition strategy for the detection of single strand nucleic acid with high discrimination factor at room temperature. The cascade recognition strategy contains a toehold mediated strand displacement and a double-toehold mediated double strand displacement reaction, thus enable the high ability to discern point mutation of target. The discrimination factor of the model target is between 45 and 109, with the medium of 70. This strategy is homogeneous, easy operation, enzyme-free, isothermal, and can be easily adapted to high-throughput devices without the need of designing complicated instruments. PMID:26745796

  3. The Synthesis of Stable, Complex Organocesium Tetramic Acids through the Ugi Reaction and Cesium-Carbonate-Promoted Cascades.

    PubMed

    Martinez-Ariza, Guillermo; Ayaz, Muhammad; Roberts, Sue A; Rabanal-León, Walter A; Arratia-Pérez, Ramiro; Hulme, Christopher

    2015-09-28

    Two structurally unique organocesium carbanionic tetramic acids have been synthesized through expeditious and novel cascade reactions of strategically functionalized Ugi skeletons delivering products with two points of potential diversification. This is the first report of the use of multicomponent reactions and subsequent cascades to access complex, unprecedented organocesium architectures. Moreover, this article also highlights the first use of mild cesium carbonate as a cesium source for the construction of cesium organometallic scaffolds. Relativistic DFT calculations provide an insight into the electronic structure of the reported compounds. PMID:26270696

  4. Sm(II)-Mediated Electron Transfer to Carboxylic Acid Derivatives: Development of Complexity-Generating Cascades.

    PubMed

    Just-Baringo, Xavier; Procter, David J

    2015-05-19

    exploited productively in efficient new processes. First, we have used internal directing groups in substrates to "switch on" productive ET to esters and amides and have exploited such an approach in tag-removal cyclization processes that deliver molecular scaffolds of significance in biology and materials science. Second, we have exploited external ligands to facilitate ET to carboxylic acid derivatives and have applied the strategy in telescoped reaction sequences. Finally, we have employed follow-up cyclizations with alkenes, alkynes, and allenes to intercept radical anion intermediates formed along the reaction path and have employed this strategy in complexity-generating cascade approaches to biologically significant molecular architectures. From our studies, it is now clear that Sm(II)-mediated ET to carboxylic acid derivatives constitutes a general strategy for inverting the polarity of the carbonyl, allowing nucleophilic carbon-centered radicals to be formed and exploited in novel chemical processes. PMID:25871998

  5. Catalysis of Cascade and Multicomponent Reactions of Carbonyl Compounds and CH Acids by Electricity.

    PubMed

    Elinson, Michail N; Vereshchagin, Anatoly N; Ryzhkov, Fedor V

    2016-08-01

    This review is concerned with modern trends in the use of electrochemically induced chain reactions in cascade and multicomponent electroorganic synthesis. The review summarizes the data on the use of electrochemically induced chain reactions in cascade and multicomponent organic synthesis, which were published mainly in the last decade. PMID:27276501

  6. Sequence-defined bioactive macrocycles via an acid-catalysed cascade reaction

    NASA Astrophysics Data System (ADS)

    Porel, Mintu; Thornlow, Dana N.; Phan, Ngoc N.; Alabi, Christopher A.

    2016-06-01

    Synthetic macrocycles derived from sequence-defined oligomers are a unique structural class whose ring size, sequence and structure can be tuned via precise organization of the primary sequence. Similar to peptides and other peptidomimetics, these well-defined synthetic macromolecules become pharmacologically relevant when bioactive side chains are incorporated into their primary sequence. In this article, we report the synthesis of oligothioetheramide (oligoTEA) macrocycles via a one-pot acid-catalysed cascade reaction. The versatility of the cyclization chemistry and modularity of the assembly process was demonstrated via the synthesis of >20 diverse oligoTEA macrocycles. Structural characterization via NMR spectroscopy revealed the presence of conformational isomers, which enabled the determination of local chain dynamics within the macromolecular structure. Finally, we demonstrate the biological activity of oligoTEA macrocycles designed to mimic facially amphiphilic antimicrobial peptides. The preliminary results indicate that macrocyclic oligoTEAs with just two-to-three cationic charge centres can elicit potent antibacterial activity against Gram-positive and Gram-negative bacteria.

  7. Mildly abnormal general movement quality in infants is associated with higher Mead acid and lower arachidonic acid and shows a U-shaped relation with the DHA/AA ratio.

    PubMed

    van Goor, S A; Schaafsma, A; Erwich, J J H M; Dijck-Brouwer, D A J; Muskiet, F A J

    2010-01-01

    We showed that docosahexaenoic acid (DHA) supplementation during pregnancy and lactation was associated with more mildly abnormal (MA) general movements (GMs) in the infants. Since this finding was unexpected and inter-individual DHA intakes are highly variable, we explored the relationship between GM quality and erythrocyte DHA, arachidonic acid (AA), DHA/AA and Mead acid in 57 infants of this trial. MA GMs were inversely related to AA, associated with Mead acid, and associated with DHA/AA in a U-shaped manner. These relationships may indicate dependence of newborn AA status on synthesis from linoleic acid. This becomes restricted during the intrauterine period by abundant de novo synthesis of oleic and Mead acids from glucose, consistent with reduced insulin sensitivity during the third trimester. The descending part of the U-shaped relation between MA GMs and DHA/AA probably indicates DHA shortage next to AA shortage. The ascending part may reflect a different developmental trajectory that is not necessarily unfavorable. PMID:20022733

  8. Development of a Quantum Cascade Laser-Based Detector for Ammonia and Nitric Acid

    SciTech Connect

    Zahniser, Mark S.; Nelson, David D.; McManus, J. Barry; Shorter, Joanne H.; Herndon, Scott C.; Jimenez, Rodrigo

    2005-12-31

    We have developed a compact, robust, atmospheric trace gas detector based on mid-infrared absorption spectroscopy using pulsed quantum cascade (QC) lasers. The spectrometer is suitable for airborne measurements of ammonia, nitric acid, formaldehyde, formic acid, methane, nitrous oxide, carbon monoxide, nitrogen dioxide and other gases that have line-resolved absorption spectra in the mid-infrared spectral region. The QC laser light source operates near room temperature with thermal electric cooling instead of liquid nitrogen which has been previously required for semiconductor lasers in the mid-infrared spectral region. The QC lasers have sufficient output power so that thermal electric cooled detectors may be used in many applications with lower precision requirements. The instrument developed in this program has been used in several field campaigns from both the Aerodyne Mobile Laboratory and from the NOAA WP3 aircraft. The Phase II program has resulted in more than 10 archival publications describing the technology and its applications. Over 12 instruments based on this design have been sold to research groups in Europe and the United States making the program both a commercial as well as a technological success. Anticipated Benefits The development of a sensitive, cryogen-free, mid-infrared absorption method for atmospheric trace gas detection will have wide benefits for atmospheric and environmental research and broader potential commercial applications in areas such as medical diagnostic and industrial process monitoring of gaseous compounds. Examples include air pollution monitoring, breath analysis, combustion exhaust diagnostics, and plasma diagnostics for semi-conductor fabrication. The substitution of near-room temperature QC lasers for cryogenic lead salt TDLs and the resulting simplifications in instrument design and operation will greatly expand the range of applications.

  9. Effect of adding amino acids residues in N- and C-terminus of Vip3Aa16 (L121I) toxin.

    PubMed

    Sellami, Sameh; Cherif, Marwa; Jamoussi, Kaïs

    2016-06-01

    To study the importance of N- and C-terminus of Bacillus thuringiensis Vip3Aa16 (L121I) toxin (88 kDa), a number of mutants were generated. The addition of two (2R: RS) or eleven (11R: RSRPGHHHHHH) amino acid residues at the Vip3Aa16 (L121I) C-terminus allowed to an unappropriated folding illustrated by the abundant presence of the 62 kDa proteolytic form. The produced Vip3Aa16 (L121I) full length form was less detected when increasing the number of amino acids residues in the C-terminus. Bioassays demonstrated that the growth of the lepidopteran Ephestia kuehniella was slightly affected by Vip3Aa16 (L121I)-2R and not affected by Vip3Aa16 (L121I)-11R. Additionally, the fusion at the Vip3Aa16 (L121I) N-terminus of 39 amino acids harboring the E. coli OmpA leader peptide and the His-tag sequence allowed to the increase of protease sensitivity of Vip3Aa16 (L121I) full length form, as only the 62 kDa proteolysis form was detected. Remarkably, this fused protein produced in Escherichia coli (E. coli) was biologically inactive toward Ephestia kuehniella larvae. Thus, the N-terminus of the protein is required to the accomplishment of the insecticidal activity of Vip3 proteins. This report serves as guideline for the study of Vip3Aa16 (L121I) protein stability and activity. PMID:26876111

  10. Effect of Dietary L-ascorbic Acid (L-AA) on Production Performance, Egg Quality Traits and Fertility in Japanese Quail (Coturnix japonica) at Low Ambient Temperature.

    PubMed

    Shit, N; Singh, R P; Sastry, K V H; Agarwal, R; Singh, R; Pandey, N K; Mohan, J

    2012-07-01

    Environmental stress boosts the levels of stress hormones and accelerates energy expenditure which subsequently imbalance the body's homeostasis. L-ascorbic acid (L-AA) has been recognized to mitigate the negative impact of environmental stress on production performances in birds. The present investigation was carried out to elucidate the effect of different dietary levels of L-AA on production performance, egg quality traits and fertility in Japanese quail at low ambient temperature. Sixty matured females (15 wks) were equally divided into three groups (20/group) based on the different dietary levels of L-AA (0, 250 and 500 ppm) and coupled with an equal number of males (1:1) obtained from the same hatch. They were managed in uniform husbandry conditions without restriction of feed and water at 14 h photo-schedule. Except for feed efficiency, body weight change, feed consumption and hen-day egg production were recorded highest in 500 ppm L-AA supplemented groups. Among the all egg quality traits studied, only specific gravity, shell weight and thickness differed significantly (p<0.05) in the present study. Fertility was improved significantly (p<0.01) to a dose dependent manner of L-AA. The findings of the present study concluded that dietary L-AA can be a caring management practice at least in part to alleviate the adverse effect of cold induced stress on production performance in Japanese quail. PMID:25049657

  11. Label-free electrochemical nucleic acid biosensing by tandem polymerization and cleavage-mediated cascade target recycling and DNAzyme amplification.

    PubMed

    Liu, Shufeng; Gong, Hongwei; Wang, Yanqun; Wang, Li

    2016-03-15

    Owing to the intrinsic importance of nucleic acid as bio-targets, the achievement of its simple and sensitive detection with high confidence is very essential for biological studies and diagnostic purposes. Herein, a label-free, isothermal, and ultrasensitive electrochemical detection of target DNA was developed by using a tandem polymerization and cleavage-mediated cascade target recycling and DNAzyme releasing amplification strategy. Upon sensing of the nucleic acid analyte for the assembled hairpin-like probe DNA on the electrode, the DNA polymerase guided the target recycling and simultaneously triggered the lambda exonuclease cleavage, accompanied by the cascade recycling of the released new complementary strand and the amplified liberation of the G-rich sequence of the HRP-mimicking DNAzyme. The electrocatalytic reduction of H2O2 by the generated hemin/G-quadruplex DNAzyme was used for the signal readout and further amplification toward target response. Such tandem functional operation by DNA polymerase, lambda exonuclease and DNAzyme endows the developed biosensor with a high sensitivity and also a high confidence. A low detection limit of 5 fM with an excellent selectivity toward target DNA could be achieved. It also exhibits the distinct advantages of simplicity in probe design and biosensor fabrication, and label-free electrochemical detection, thus may offer a promising avenue for the applications in disease diagnosis and clinical biomedicine. PMID:26513289

  12. Different roles of protein kinase C-beta and -delta in arachidonic acid cascade, superoxide formation and phosphoinositide hydrolysis.

    PubMed Central

    Duyster, J; Schwende, H; Fitzke, E; Hidaka, H; Dieter, P

    1993-01-01

    In contrast with protein kinase C (PKC)-beta, PKC-delta is exclusively detectable in the membrane fraction of liver macrophages. After long-term treatment with phorbol 12-myristate 13-acetate (PMA) PKC-beta is depleted faster (within 3 h) than PKC-delta (> 7h). Simultaneously, pretreatment with PMA for 3 h inhibits the PMA- and zymosan-induced generation of superoxide and the PMA-induced formation of prostaglandin (PG) E2, whereas a preincubation of more than 7 h is required to affect the zymosan-induced release of PGE2 and inositol phosphates. These results support an involvement of PKC-beta in the PMA-induced activation of the arachidonic acid cascade and in superoxide formation and imply an involvement of PKC-delta in zymosan-induced phosphoinositide hydrolysis and PGE2 formation. Two phorbol ester derivates, sapintoxin A (SAPA) and 12-deoxyphorbol 13-phenylacetate 20-acetate (DOPPA), which have been previously reported to activate preferentially PLC-beta but not PKC-delta in vitro [Ryves, Evans, Olivier, Parker and Evans (1992) FEBS Lett. 288, 5-9], induce the formation of PGE2 and superoxide, down-regulate PKC-delta and potentiate inositol phosphate formation in parallel SAPA, but not DOPPA, down-regulates PKC-beta and inhibits the PMA-induced formation of eicosanoids and superoxide. Images Figure 1 Figure 2 Figure 5 PMID:8389125

  13. Influence of ascorbic acid (AA) on iron (Fe) utilization in copper (Cu) deficient male and female rats

    SciTech Connect

    Johnson, M.A. )

    1989-02-09

    Interactions between Cu status (-Cu: 1.0 mg Cu/kg diet or +Cu: 5.8 mg Cu/kg diet) and AA (0 or 1% of the diet) were compared in male and female weanling rats. Food intakes were controlled so that final body weights were similar on day 23 when rats were killed. On day 17 rats were given an oral dose of 4 uCi of Fe-59 and feces were collected for 5 days. Heart weights (g/100 g body weight) were increased in both male and female -Cu rats. Among -Cu rats, AA increased heart weight by 25% in females but by only 6% in males. Similarly, among -Cu rats AA increased liver weight (g/100 g body weight) by 16% in females but not at all in males. Hematocrits (%) were similar among +Cu rats but were decreased in -Cu rats to a greater in male than in female rats. However, among -Cu rats AA decreased hematocrits from 34.1 to 26.4% in females but from only 30.0 to 26.8% in males. Compared to -Cu rats, +Cu rats apparently absorbed 2-times more Fe-59 and retained 2.5- times more absorbed Fe-59 in their whole blood. Among -Cu rats, AA decreased the absorption of Fe-59 and whole blood Fe-59 to a greater extent in female than in male rats. These results suggest that female rats may be somewhat more sensitive to the adverse effects of AA during Cu deficiency than are male rats.

  14. An asymmetric synthesis of 1,2,4-trioxane anticancer agents via desymmetrization of peroxyquinols through a Brønsted acid catalysis cascade.

    PubMed

    Rubush, David M; Morges, Michelle A; Rose, Barbara J; Thamm, Douglas H; Rovis, Tomislav

    2012-08-22

    The desymmetrization of p-peroxyquinols using a Brønsted acid-catalyzed acetalization/oxa-Michael cascade was achieved in high yields and selectivities for a variety of aliphatic and aryl aldehydes. Mechanistic studies suggest that the reaction proceeds through a dynamic kinetic resolution of the peroxy hemiacetal intermediate. The resulting 1,2,4-trioxane products were derivatized and show potent cancer cell-growth inhibition. PMID:22871165

  15. EB1 Levels Are Elevated in Ascorbic Acid (AA)-stimulated Osteoblasts and Mediate Cell-Cell Adhesion-induced Osteoblast Differentiation*

    PubMed Central

    Pustylnik, Sofia; Fiorino, Cara; Nabavi, Noushin; Zappitelli, Tanya; da Silva, Rosa; Aubin, Jane E.; Harrison, Rene E.

    2013-01-01

    Osteoblasts are differentiated mesenchymal cells that function as the major bone-producing cells of the body. Differentiation cues including ascorbic acid (AA) stimulation provoke intracellular changes in osteoblasts leading to the synthesis of the organic portion of the bone, which includes collagen type I α1, proteoglycans, and matrix proteins, such as osteocalcin. During our microarray analysis of AA-stimulated osteoblasts, we observed a significant up-regulation of the microtubule (MT) plus-end binding protein, EB1, compared with undifferentiated osteoblasts. EB1 knockdown significantly impaired AA-induced osteoblast differentiation, as detected by reduced expression of osteoblast differentiation marker genes. Intracellular examination of AA-stimulated osteoblasts treated with EB1 siRNA revealed a reduction in MT stability with a concomitant loss of β-catenin distribution at the cell cortex and within the nucleus. Diminished β-catenin levels in EB1 siRNA-treated osteoblasts paralleled an increase in phospho-β-catenin and active glycogen synthase kinase 3β, a kinase known to target β-catenin to the proteasome. EB1 siRNA treatment also reduced the expression of the β-catenin gene targets, cyclin D1 and Runx2. Live immunofluorescent imaging of differentiated osteoblasts revealed a cortical association of EB1-mcherry with β-catenin-GFP. Immunoprecipitation analysis confirmed an interaction between EB1 and β-catenin. We also determined that cell-cell contacts and cortically associated EB1/β-catenin interactions are necessary for osteoblast differentiation. Finally, using functional blocking antibodies, we identified E-cadherin as a major contributor to the cell-cell contact-induced osteoblast differentiation. PMID:23740245

  16. Asymmetric Anion-π Catalysis of Iminium/Nitroaldol Cascades To Form Cyclohexane Rings with Five Stereogenic Centers Directly on π-Acidic Surfaces.

    PubMed

    Liu, Le; Cotelle, Yoann; Avestro, Alyssa-Jennifer; Sakai, Naomi; Matile, Stefan

    2016-06-29

    Anion-π interactions have been introduced to catalysis only recently, and evidence for their significance is so far limited to one classical model reaction in enolate and enamine chemistry. In this report, asymmetric anion-π catalysis is achieved for the first time for a more demanding cascade process. The selected example affords six-membered carbocycles with five stereogenic centers in a single step from achiral and acyclic substrates. Rates, yields, turnover, diastereo- and enantioselectivity are comparable with conventional catalysts. Rates and stereoselectivity increase with the π-acidity of the new anion-π catalysts. Further support for operational anion-π interactions in catalysis is obtained from inhibition with nitrate. As part of the stereogenic cascade reaction, iminium chemistry and conjugate additions are added to the emerging repertoire of asymmetric anion-π catalysis. PMID:27327089

  17. 40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (40 CFR Part 63, Subpart A) to Subpart AA A Appendix A to Subpart AA of Part 63 Protection of... Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to Subpart AA of Part 63—Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA 40...

  18. 40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (40 CFR Part 63, Subpart A) to Subpart AA A Appendix A to Subpart AA of Part 63 Protection of... Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to Subpart AA of Part 63—Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA 40...

  19. 40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (40 CFR Part 63, Subpart A) to Subpart AA A Appendix A to Subpart AA of Part 63 Protection of... Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to Subpart AA of Part 63—Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA 40...

  20. 40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (40 CFR Part 63, Subpart A) to Subpart AA A Appendix A to Subpart AA of Part 63 Protection of... Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to Subpart AA of Part 63—Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA 40...

  1. 40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (40 CFR Part 63, Subpart A) to Subpart AA A Appendix A to Subpart AA of Part 63 Protection of... Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to Subpart AA of Part 63—Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA 40...

  2. Doped copolymer of polyanthranilic acid and o-aminophenol (AA-co-OAP): Synthesis, spectral characterization and the use of the doped copolymer as precursor of α-Fe2O3 nanoparticles

    NASA Astrophysics Data System (ADS)

    Hosny, Nasser Mohammed; Nowesser, Nourhan; Al-Hussaini, A. S.; Zoromba, Mohamed Shafick

    2016-02-01

    The copolymer of anthranilic acid and o-aminophenol (AA-co-OAP) was synthesized and characterized by IR, UV-Vis. and thermal analyses (TGA). Linear chain mode was suggested for the pure (AA-co-OAP). The effect of inclusion of MnCl2, CoCl2, NiCl2, CuCl2 and FeCl3 on the spectral, thermal and optical properties of AA-co-OAP has been studied. Octahedral stereochemistry was suggested for Fe, Mn and Ni doped AA-co-OAP, while tetrahedral and square-planar geometries were suggested for Co and Cu doped AA-co-OAP, respectively. Fe doped AA-co-OAP has been used as a precursor for α-Fe2O3 nanoparticles by thermal decomposition route at 800 °C. The obtained hematite has been characterized by XRD and TEM. The average size of the prepared nanoparticles was estimated as 34 nm. The optical band gap of the synthesized hematite nanoparticles was measured and compared with the bulk.

  3. Oxidative potential of ambient water-soluble PM2.5 in the southeastern United States: contrasts in sources and health associations between ascorbic acid (AA) and dithiothreitol (DTT) assays

    NASA Astrophysics Data System (ADS)

    Fang, Ting; Verma, Vishal; Bates, Josephine T.; Abrams, Joseph; Klein, Mitchel; Strickland, Matthew J.; Sarnat, Stefanie E.; Chang, Howard H.; Mulholland, James A.; Tolbert, Paige E.; Russell, Armistead G.; Weber, Rodney J.

    2016-03-01

    The ability of certain components of particulate matter to induce oxidative stress through the generation of reactive oxygen species (ROS) in vivo may be one mechanism accounting for observed linkages between ambient aerosols and adverse health outcomes. A variety of assays have been used to measure this so-called aerosol oxidative potential. We developed a semi-automated system to quantify oxidative potential of filter aqueous extracts utilizing the dithiothreitol (DTT) assay and report here the development of a similar semi-automated system for the ascorbic acid (AA) assay. Approximately 500 PM2.5 filter samples collected in contrasting locations in the southeastern US were analyzed for a host of aerosol species, along with AA and DTT activities. We present a detailed contrast in findings from these two assays. Water-soluble AA activity was higher in summer and fall than in winter, with highest levels near heavily trafficked highways, whereas DTT activity was higher in winter compared to summer and fall and more spatially homogeneous. AA activity was nearly exclusively correlated with water-soluble Cu (r = 0.70-0.94 at most sites), whereas DTT activity was correlated with organic and metal species. Source apportionment models, positive matrix factorization (PMF) and a chemical mass balance method with ensemble-averaged source impact profiles (CMB-E), suggest a strong contribution from traffic emissions and secondary processes (e.g., organic aerosol oxidation or metals mobilization by secondary acids) to both AA and DTT activities in urban Atlanta. In contrast, biomass burning was a large source for DTT activity, but insignificant for AA. AA activity was not correlated with PM2.5 mass, while DTT activity co-varied strongly with mass (r = 0.49-0.86 across sites and seasons). Various linear models were developed to estimate AA and DTT activities for the central Atlanta Jefferson Street site, based on the CMB-E sources. The models were then used to estimate daily

  4. Oxidative potential of ambient water-soluble PM2.5 measured by Dithiothreitol (DTT) and Ascorbic Acid (AA) assays in the southeastern United States: contrasts in sources and health associations

    NASA Astrophysics Data System (ADS)

    Fang, T.; Verma, V.; Bates, J. T.; Abrams, J.; Klein, M.; Strickland, M. J.; Sarnat, S. E.; Chang, H. H.; Mulholland, J. A.; Tolbert, P. E.; Russell, A. G.; Weber, R. J.

    2015-11-01

    The ability of certain components of particulate matter to induce oxidative stress through catalytic generation of reactive oxygen species (ROS) in vivo may be one mechanism accounting for observed linkages between ambient aerosols and adverse health outcomes. A variety of assays have been used to measure this so-called aerosol oxidative potential. We developed a semi-automated system to quantify oxidative potential of filter aqueous extracts utilizing the dithiothreitol (DTT) assay and have recently developed a similar semi-automated system using the ascorbic acid (AA) assay. Approximately 500 PM2.5 filter samples collected in contrasting locations in the southeastern US were analyzed using both assays. We found that water-soluble DTT activity on a per air volume basis was more spatially uniform than water-soluble AA activity. DTT activity was higher in winter than in summer/fall, whereas AA activity was higher in summer/fall compared to winter, with highest levels near highly trafficked highways. DTT activity was correlated with organic and metal species, whereas AA activity was correlated with water-soluble metals (especially water-soluble Cu, r=0.70-0.91 at most sites). Source apportionment models, Positive Matrix Factorization (PMF) and a Chemical Mass Balance Method with ensemble-averaged source impact profiles (CMB-E), suggest a strong contribution from secondary processes (e.g., organic aerosol oxidation or metal mobilization by formation of an aqueous particle with secondary acids) and traffic emissions to both DTT and AA activities in urban Atlanta. Biomass burning was a large source for DTT activity, but insignificant for AA. DTT activity was well correlated with PM2.5 mass (r=0.49-0.86 across sites/seasons), while AA activity did not co-vary strongly with mass. A linear model was developed to estimate DTT and AA activities for the central Atlanta Jefferson Street site, based on the CMB-E sources that are statistically significant with positive

  5. Inhibition of arachidonic acid metabolism and its implication on cell proliferation and tumour-angiogenesis.

    PubMed

    Hyde, C A C; Missailidis, S

    2009-06-01

    Arachidonic acid (AA) and its metabolites have recently generated a heightened interest due to growing evidence of their significant role in cancer biology. Thus, inhibitors of the AA cascade, first and foremost COX inhibitors, which have originally been of interest in the treatment of inflammatory conditions and certain types of cardiovascular disease, are now attracting attention as an arsenal against cancer. An increasing number of investigations support their role in cancer chemoprevention, although the precise molecular mechanisms that link levels of AA, and its metabolites, with cancer progression have still to be elucidated. This article provides an overview of the AA cascade and focuses on the roles of its inhibitors and their implication in cancer treatment. In particular, emphasis is placed on the inhibition of cell proliferation and neo-angiogenesis through inhibition of the enzymes COX-2, 5-LOX and CYP450. Downstream effects of inhibition of AA metabolites are analysed and the molecular mechanisms of action of a selected number of inhibitors of catalytic pathways reviewed. Lastly, the benefits of dietary omega-3 fatty acids and their mechanisms of action leading to reduced cancer risk and impeded cancer cell growth are mentioned. Finally, a proposal is put forward, suggesting a novel and integrated approach in viewing the molecular mechanisms and complex interactions responsible for the involvement of AA metabolites in carcinogenesis and the protective effects of omega-3 fatty acids in inflammation and tumour prevention. PMID:19239926

  6. USEPA METHOD STUDY 37 - SW-846 METHOD 3050, ACID DIGESTION OF SEDIMENTS, SLUDGES AND SOILS BY AA-DIRECT ASPIRATION

    EPA Science Inventory

    An interlaboratory collaborative study was conducted to determine the precision and accuracy of Method 3050 for the analysis of 23 elements in sediments, sludqes and soils. Method 3050 is entitled, "Acid Digestion of Sediments, Sludges and Soils." It includes instructions for qua...

  7. pH-sensing properties of cascaded long- and short-period fiber grating with poly acrylic acid/poly allylamine hydrochloride thin-film overlays

    NASA Astrophysics Data System (ADS)

    Yang, Ying

    2014-11-01

    Based on coupled-mode theory and transfer matrix method, the mode coupling mechanism and the reflection spectral properties of coated cascaded long- and short-period gratings (CLBG) are discussed. The effects of the thin-film parameters (film refractive index and film thickness) on the reflection spectra of the coated CLBG are simulated. By using electrostatic self-assembly method, poly acrylic acid (PAA) and poly allylamine hydrochloride (PAH) multilayer molecular pH-sensitive thin-films are assembled on the surface of the partial corroded CLBG. When the CLBG coated with PAA/PAH films are used to sense pH values, the resonant wavelengths of the CLBG have almost no shift, whereas the resonance peak reflectivities change with pH values. In addition, the sensitivities of the resonance peak reflectivities responding to pH values are improved by an order of magnitude.

  8. An organocatalytic Michael-cyclization cascade of 4-oxa-α,β-unsaturated carboxylic acids with aldehydes: facile synthesis of chiral γ-lactols and trisubstituted γ-lactones.

    PubMed

    Lin, Jun-Bing; Xu, Shi-Ming; Xie, Ji-Kang; Li, Hong-Yu; Xu, Peng-Fei

    2015-02-28

    An organocatalytic Michael-cyclization cascade of aldehydes with 4-oxa-α,β-unsaturated carboxylic acids has been developed, giving functionalized γ-lactols with high yields and enantioselectivities. The products could be easily transformed into complex trisubstituted γ-lactones and γ-lactams. PMID:25633800

  9. Site-saturation engineering of lysine 47 in cyclodextrin glycosyltransferase from Paenibacillus macerans to enhance substrate specificity towards maltodextrin for enzymatic synthesis of 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G).

    PubMed

    Han, Ruizhi; Liu, Long; Shin, Hyun-dong; Chen, Rachel R; Du, Guocheng; Chen, Jian

    2013-07-01

    In this work, the site-saturation engineering of lysine 47 in cyclodextrin glycosyltransferase (CGTase) from Paenibacillus macerans was conducted to improve the specificity of CGTase towards maltodextrin, which can be used as a cheap and easily soluble glycosyl donor for the enzymatic synthesis of 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G) by CGTase. When using maltodextrin as glycosyl donor, four mutants K47F (lysine→ phenylalanine), K47L (lysine→ leucine), K47V (lysine→ valine) and K47W (lysine→ tryptophan) showed higher AA-2G yield as compared with that produced by the wild-type CGTase. The transformation conditions (temperature, pH and the mass ratio of L-ascorbic acid to maltodextrin) were optimized and the highest titer of AA-2G produced by the mutant K47L could reach 1.97 g/l, which was 64.2% higher than that (1.20 g/l) produced by the wild-type CGTase. The reaction kinetics analysis confirmed the enhanced maltodextrin specificity, and it was also found that compared with the wild-type CGTase, the four mutants had relatively lower cyclization activities and higher disproportionation activities, which was favorable for AA-2G synthesis. The mechanism responsible for the enhanced substrate specificity was further explored by structure modeling and it was indicated that the enhancement of maltodextrin specificity may be due to the short residue chain and the removal of hydrogen bonding interactions between the side chain of residue 47 and the sugar at -3 subsite. Here the obtained mutant CGTases, especially the K47L, has a great potential in the production of AA-2G with maltodextrin as a cheap and easily soluble substrate. PMID:23129181

  10. Ultrasensitive electrochemical detection of nucleic acid by coupling an autonomous cascade target replication and enzyme/gold nanoparticle-based post-amplification.

    PubMed

    Liu, Shufeng; Wei, Wenji; Wang, Yanqun; Fang, Li; Wang, Li; Li, Feng

    2016-06-15

    Owing to the intrinsic importance of nucleic acid as bio-targets, the development of isothermal and ultrasensitive electrochemical DNA biosensor is very essential for biological studies and medical diagnostics. Herein, the autonomous cascade DNA replication strategy was effectively married with the enzyme/gold nanoparticle-based post-amplification strategy to promote the detection performance toward target DNA. A hairpin DNA probe (HP) is designed that consists of an overhang at 3'-end as the recognition unit for target DNA, a recognition site for nicking endonuclease, and an alkane spacer to terminate polymerization reaction. The autonomous DNA replication-scission-displacement reaction operated by the nicking endonuclease/KF polymerase induced the autocatalytic opening of HP, which was then specifically bound by the enzyme/gold nanoparticles for further dual-signal amplification toward target-related sensing events. A low detection limit of 0.065fM with an excellent selectivity toward target DNA could be achieved. The proposed biosensor could be also easily regenerated for target detection. The developed biosensor creates an opportunity for the effective coupling of the target replication with post-amplification strategies and thus opens a promising avenue for the detection of nucleic acid with low abundance in bioanalysis and clinical biomedicine. PMID:26849348

  11. Application of a continuous bioreactor cascade to study the effect of linoleic acid on hybridoma cell physiology.

    PubMed

    Kisztelinski, Dominik; Alink, Gerrit M; Rietjens, Ivonne M C M; Bielecki, Stanislaw; Tramper, Johannes; Martens, Dirk E

    2006-10-20

    The aim of the present study is to demonstrate the use of controlled bioreactors for toxicological studies. As a model system the effect of linoleic acid on hybridoma cells is studied in two well-controlled continuously operated bioreactors placed in series. In the first reactor the effect on rapid proliferating cells can be studied, while in the second reactor a special steady state is created, which allows studying the effect on apoptotic cells. Experiments are done at 0, 25, and 50 microM linoleic acid. At the end of the experiment with 50 microM linoleic acid, the concentration of linoleic acid is increased stepwise to determine the cytotoxic level. For rapid proliferating cells exposed to 25 and 50 microM stimulation of growth was observed. At 50 microM there was at the same time an increase in cell death through apoptosis. For stressed apoptotic cells linoleic acid caused partial growth inhibition at 25 and 50 microM and arrest of cell proliferation in the G(2)/M phase at 50 microM. For both, rapid proliferating cells and stressed apoptotic cells, complete growth inhibition occurred at 85 microM, with cells being arrested in the G(2)/M phase and dying mainly through necrosis. Cells in the bioreactor system appeared to be more sensitive towards linoleic acid than cells grown in multi-well plates. (IC(50) = 300 microM; IC(100) = 400 microM). Altogether the results of the present study reveal that the biostat experiments allow detailed analysis of the effect of a bioactive ingredient on cell physiology and behavior. PMID:16894630

  12. Protective effects of ascorbic acid against the genetic and epigenetic alterations induced by 3,5-dimethylaminophenol in AA8 cells.

    PubMed

    Chao, Ming-Wei; Erkekoglu, Pınar; Tseng, Chia-Yi; Ye, Wenjie; Trudel, Laura J; Skipper, Paul L; Tannenbaum, Steven R; Wogan, Gerald N

    2015-05-01

    Exposure to monocyclic aromatic alkylanilines (MAAs), namely 2,6-dimethylaniline (2,6-DMA), 3,5-dimethylaniline (3,5-DMA) and 3-ethylaniline (3-EA), was significantly and independently associated with bladder cancer incidence. 3,5-DMAP (3,5-dimethylaminophenol), a metabolite of 3,5-DMA, was shown to induce an imbalance in cytotoxicity cellular antioxidant/oxidant status, and DNA damage in mammalian cell lines. This study was designed to evaluate the protective effect of ascorbic acid (Asc) against the cytotoxicity, reactive oxygen species (ROS) production, genotoxicity and epigenetic changes induced by 3,5-DMAP in AA8 Chinese Hamster Ovary (CHO) cells. In different cellular fractions, 3,5-DMAP caused alterations in the enzyme activities orchestrating a cellular antioxidant balance, decreases in reduced glutathione levels and a cellular redox ratio as well as increases in lipid peroxidation and protein oxidation. We also suggest that the cellular stress caused by this particular alkylaniline leads to both genetic (Aprt mutagenesis) and epigenetic changes in histones 3 and 4 (H3 and H4). This may further cause molecular events triggering different pathological conditions and eventually cancer. In both cytoplasm and nucleus, Asc provided increases in 3,5-DMAP-reduced glutathione levels and cellular redox ratio and decreases in the lipid peroxidation and protein oxidation. Asc was also found to be protective against the genotoxic and epigenetic effects initiated by 3,5-DMAP. In addition, Asc supplied protection against the cell cycle (G1 phase) arrest induced by this particular alkylaniline metabolite. PMID:25178734

  13. Proteomics analysis of global regulatory cascades involved in clavulanic acid production and morphological development in Streptomyces clavuligerus.

    PubMed

    Ferguson, Nicole L; Peña-Castillo, Lourdes; Moore, Marcus A; Bignell, Dawn R D; Tahlan, Kapil

    2016-04-01

    The genus Streptomyces comprises bacteria that undergo a complex developmental life cycle and produce many metabolites of importance to industry and medicine. Streptomyces clavuligerus produces the β-lactamase inhibitor clavulanic acid, which is used in combination with β-lactam antibiotics to treat certain β-lactam resistant bacterial infections. Many aspects of how clavulanic acid production is globally regulated in S. clavuligerus still remains unknown. We conducted comparative proteomics analysis using the wild type strain of S. clavuligerus and two mutants (ΔbldA and ΔbldG), which are defective in global regulators and vary in their ability to produce clavulanic acid. Approximately 33.5 % of the predicted S. clavuligerus proteome was detected and 192 known or putative regulatory proteins showed statistically differential expression levels in pairwise comparisons. Interestingly, the expression of many proteins whose corresponding genes contain TTA codons (predicted to require the bldA tRNA for translation) was unaffected in the bldA mutant. PMID:26790415

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  15. Lipoteichoic acid modulates inflammatory response in macrophages after phagocytosis of titanium particles through Toll-like receptor 2 cascade and inflammasomes.

    PubMed

    Naganuma, Yasushi; Takakubo, Yuya; Hirayama, Tomoyuki; Tamaki, Yasunobu; Pajarinen, Jukka; Sasaki, Kan; Goodman, Stuart B; Takagi, Michiaki

    2016-02-01

    Toll-like receptor 2 (TLR2) and nucleotide-binding and oligomerization domain-like receptors with a pyrin domain 3 (NLRP3) inflammasomes have been presumed to participate in the pathogenesis of aseptic implant loosening. The aim of this study is to analyze the cellular localization of TLR2 and NLRP3 inflammasomes in the periprosthetic tissue from aseptically loose hip implants as well as the expression of these molecules in macrophages stimulated in vitro with titanium particles (Ti) coated with lipoteichoic acid (LTA). Using immunohistochemistry, immunoreactivity of TLR2 and NLRP3 inflammasomes was found in macrophages within the foreign body granulomatosis. Using RAW264.7 cells, stimulation with Ti increased the messenger RNA (mRNA) levels of TLR2 and TNF-α. Stimulation with LTA-coated Ti enhanced mRNA levels of NLRP3 and IL-1β, whereas reinforced secretion of IL-1β was not detected in spite of marked release of TNF-α. Finally, the same cells with silenced Irak2, an adaptor protein in the TLR2 cascade, suppressed this NLRP3 upregulation. This study suggests that TLR2 and NLRP3 inflammasomes are factors involved in cross-talk mediating the foreign body type response to wear particles. In addition, discrepant behavior in the release between TNF-α and IL-1β release may explain the variable pathomechanisms of aseptic implant loosening without acute inflammatory reactions. PMID:26440284

  16. FIA functions as an early signal component of abscisic acid signal cascade in Vicia faba guard cells.

    PubMed

    Sugiyama, Yusuke; Uraji, Misugi; Watanabe-Sugimoto, Megumi; Okuma, Eiji; Munemasa, Shintaro; Shimoishi, Yasuaki; Nakamura, Yoshimasa; Mori, Izumi C; Iwai, Sumio; Murata, Yoshiyuki

    2012-02-01

    An abscisic acid (ABA)-insensitive Vicia faba mutant, fia (fava bean impaired in ABA-induced stomatal closure) had previously been isolated. In this study, it was investigated how FIA functions in ABA signalling in guard cells of Vicia faba. Unlike ABA, methyl jasmonate (MeJA), H(2)O(2), and nitric oxide (NO) induced stomatal closure in the fia mutant. ABA did not induce production of either reactive oxygen species or NO in the mutant. Moreover, ABA did not suppress inward-rectifying K(+) (K(in)) currents or activate ABA-activated protein kinase (AAPK) in mutant guard cells. These results suggest that FIA functions as an early signal component upstream of AAPK activation in ABA signalling but does not function in MeJA signalling in guard cells of Vicia faba. PMID:22131163

  17. Comparison between the AA/EPA ratio in depressed and non depressed elderly females: omega-3 fatty acid supplementation correlates with improved symptoms but does not change immunological parameters

    PubMed Central

    2012-01-01

    Background Depression is one of the most frequently missed diagnoses in elderly people, with obvious negative effects on quality of life. Various studies have shown that long chain omega-3 polyunsaturated fatty acids (n-3 PUFA) may be useful in its management. Our objective was to evaluate whether a supplement containing n-3 PUFA improves depressive symptoms in depressed elderly patients, and whether the blood fatty acid pattern is correlated with these changes. Methods The severity of depressive symptoms according to the Geriatric Depression Scale (GDS), blood fatty acid composition and erythrocyte phospholipids were analyzed in 46 depressed females aged 66-95y, diagnosed with depression according to DSMIV, within the context of a randomized, double-blind, placebo-controlled trial. 22 depressed females were included in the intervention group (2.5 g/day of n-3 PUFA for 8 weeks), and 24 in the placebo group. We also measured immunological parameters (CD2, CD3, CD4, CD8, CD16, CD19 and cytokines (IL-5, IL-15). Results The mean GDS score and AA/EPA ratio, in whole blood and RBC membrane phospholipids, were significantly lower after 2 months supplementation with n-3 PUFA. A significant correlation between the amelioration of GDS and the AA/EPA ratio with some immunological parameters, such as CD2, CD19, CD4, CD16 and the ratio CD4/CD8, was also found. Nevertheless, omega-3 supplementation did not significantly improve the studied immunological functions. Conclusions n-3 PUFA supplementation ameliorates symptoms in elderly depression. The n-3 PUFA status may be monitored by means of the determination of whole blood AA/EPA ratio. PMID:23046564

  18. Cu(II)-catalyzed reactions in ternary [Cu(AA)(AA - H)]+ complexes (AA = Gly, Ala, Val, Leu, Ile, t-Leu, Phe).

    PubMed

    Wang, Ping; Ohanessian, Gilles; Wesdemiotis, Chrys

    2009-01-01

    The unimolecular chemistry of [Cu(II)AA(AA - H)](+) complexes, composed of an intact and a deprotonated amino acid (AA) ligand, have been probed in the gas phase by tandem and multistage mass spectrometry in an electrospray ionization quadrupole ion trap mass spectrometer. The amino acids examined include Gly, Ala, Val, Leu, Ile, t-Leu and Phe. Upon collisionally-activated dissociation (CAD), the [Cu(II)AA(AA - H)](+) complexes undergo decarboxylation with simultaneous reduction of Cu(II) to Cu(I); during this process, a radical site is created at the alpha-carbon of the decarboxylated ligand (H(2)N(1) - (*)C(alpha)H - C(beta)H(2) - R; R = side chain substituent). The radical site is able to move along the backbone of the decarboxylated amino acid to form two new radicals (HN(1)(*) - C(alpha)H(2) - C(beta)H(2) - R and H(2)N(1) - C(alpha)H(2) - (*)C(beta)H - R). From the complexes of Gly and t-Leu, only C(alpha) and N(1) radicals can be formed. The whole radical ligand can be lost to form [Cu(I)AA](+) from these three isomeric radicals. Alternatively, further radical induced dissociations can take place along the backbone of the decarboxylated amino acid ligand to yield [Cu(II)AA(AA - 2H - CO(2))](+), [Cu(I)AA((*)NH(2))](+), [Cu(I)AA(HN = C(alpha)H(2))](+), or [Cu(I)AA(H(2)N - C(alpha)H = C(beta)H - R'](+) (R' = partial side chain substituent). The sodiated copper complexes, [Cu(II)(AA - H + Na)(AA - H)](+), show the same fragmentation patterns as their non-sodiated counterparts; sodium ion is retained on the intact amino acid ligand and is not involved in the CAD pathways. The amino groups of both AA units, the carbonyl group of the intact amino acid, and the deprotonated hydroxyl oxygen coordinate Cu(II) in square-planar fashion. Ab initio calculations indicate that the metal ion facilitates hydrogen atom shuttling between the N(1), C(alpha) and C(beta) atoms of the decarboxylated amino acid ligand. The dissociations of the decarboxylated radical ions unveil

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

    SciTech Connect

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

    2015-03-09

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

  20. Single amino acid insertions in extracellular loop 2 of Bombyx mori ABCC2 disrupt its receptor function for Bacillus thuringiensis Cry1Ab and Cry1Ac but not Cry1Aa toxins.

    PubMed

    Tanaka, Shiho; Miyamoto, Kazuhisa; Noda, Hiroaki; Endo, Haruka; Kikuta, Shingo; Sato, Ryoichi

    2016-04-01

    In a previous report, seven Cry1Ab-resistant strains were identified in the silkworm, Bombyx mori; these strains were shown to have a tyrosine insertion at position 234 in extracellular loop 2 of the ABC transporter C2 (BmABCC2). This insertion was confirmed to destroy the receptor function of BmABCC2 and confer the strains resistance against Cry1Ab and Cry1Ac. However, these strains were susceptible to Cry1Aa. In this report, we examined the mechanisms of the loss of receptor function of the transporter by expressing mutations in Sf9 cells. After replacement of one or two of the five amino acid residues in loop 2 of the susceptible BmABCC2 gene [BmABCC2_S] with alanine, cells still showed susceptibility, retaining the receptor function. Five mutants with single amino acid insertions at position 234 in BmABCC2 were also generated, resulting in loop 2 having six amino acids, which corresponds to replacing the tyrosine insertion in the resistant BmABCC2 gene [BmABCC2_R(+(234)Y)] with another amino acid. All five mutants exhibited loss of function against Cry1Ab and Cry1Ac. These results suggest that the amino acid sequence in loop 2 is less important than the loop size (five vs. six amino acids) or loop structure for Cry1Ab and Cry1Ac activity. Several domain-swapped mutant toxins were then generated among Cry1Aa, Cry1Ab, and Cry1Ac, which are composed of three domains. Swapped mutants containing domain II of Cry1Ab or Cry1Ac did not kill Sf9 cells expressing BmABCC2_R(+(234)Y), suggesting that domain II of the Cry toxin is related to the interaction with the receptor function of BmABCC2. This also suggests that different reactions against Bt-toxins in some B. mori strains, that is, Cry1Ab resistance or Cry1Aa susceptibility, are attributable to structural differences in domain II of Cry1A toxins. PMID:26928903

  1. Chronic Valproate Treatment Blocks D2-like Receptor-Mediated Brain Signaling via Arachidonic Acid in Rats

    PubMed Central

    Ramadan, Epolia; Basselin, Mireille; Taha, Ameer Y.; Cheon, Yewon; Chang, Lisa; Chen, Mei; Rapoport, Stanley I.

    2011-01-01

    Background and Objective Hyperdopaminergic signaling and an upregulated brain arachidonic acid (AA) cascade may contribute to bipolar disorder (BD). Lithium and carbamazepine, FDA-approved for the treatment of BD, attenuate brain dopaminergic D2-like (D2, D3, and D4) receptor signaling involving AA when given chronically to awake rats. We hypothesized that valproate (VPA), with mood-stabilizing properties, would also reduce the D2-like-mediated signaling via AA. Methods An acute dose of quinpirole (1 mg/kg) or saline was administered to unanesthetized rats that had been treated for 30 days with a therapeutically relevant dose of VPA (200 mg/kg/day) or vehicle. Regional brain AA incorporation coefficients, k*, and incorporation rates, Jin, markers of AA signaling and metabolism, were measured by quantitative autoradiography after intravenous [1-14C]AA infusion. Whole brain concentrations of prostaglandin (PG)E2 and thromboxane (TX)B2 also were measured. Results Quinpirole compared to saline significantly increased k* in 40 of 83 brain regions, and increased brain concentrations of PGE2 in chronic vehicle-treated rats. VPA treatment by itself reduced concentrations of plasma unesterified AA and whole brain PGE2 and TXB2, and blocked the quinpirole-induced increments in k* and PGE2. Conclusion These results further support our hypothesis that similar to lithium and carbamazepine, VPA downregulates brain dopaminergic D2-like receptor-signaling involving AA. PMID:21839100

  2. Effect of allicin (diallyl disulfide-oxide) on prostaglandin endoperoxide H/sub 2/ (PGH/sub 2/) and arachidonic acid (AA) metabolism and platelet aggregation

    SciTech Connect

    Mayeux, P.R.; Agrawal, K.C.; King, B.T.; Kadowitz, P.J.; McNamara, D.B.

    1986-03-01

    The authors report here the effects of pure allicin (the antibacterial component of GO), synthesized from diallyl disulfide and hydrogen peroxide, on human platelet aggregation, PGH/sub 2/ metabolism in microsomes of bovine lung (BL) and bovine coronary artery (BCA), homogenates of human platelet (HP), and on AA metabolism in HP. Allicin at 16 ..mu..g/ml to 160 ..mu..g/ml produced concentration-dependent inhibition of platelet aggregation to 1.6 mM AA and 2.8 ..mu..M U 46619, a stable analog of PGH/sub 2/ and a TXA/sub 2/ minic. BL (200 ..mu..g protein), BCA (10 ..mu..g protein), and HP (1500 ..mu..g protein) were incubated with 10 ..mu..M (/sup 14/C) PGH/sub 2/ +/- allicin. HP (1500 ..mu..g protein) were incubated with 20 ..mu..M (/sup 14/C) AA +/- allicin. Products were separated by TLC and quantified by radiochromatographic scan. Allicin in the concentration range of 10-/sup 6/M-10-/sup 3/M induced no change in the formation of prostacyclin by BL and BCA or of TXA/sub 2/ by BL and HP. These data suggest that the platelet antiaggregatory action of allicin is not due to inhibition of cyclooxygenase or TXA/sub 2/ synthetase in the human platelet, but may be related to interactions at the TXA/sub 2/ receptor or on cyclic nucleotide levels.

  3. Section AA Pre2004 Fire, Section AA 2009, Section AA, South ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Section A-A Pre-2004 Fire, Section A-A 2009, Section A-A, South Elevation - Boston & Maine Railroad, Berlin Branch Bridge #148.81, Formerly spanning Moose Brook at former Boston & Maine Railroad, Gorham, Coos County, NH

  4. The autotaxin-lysophosphatidic acid-lysophosphatidic acid receptor cascade: proposal of a novel potential therapeutic target for treating glioblastoma multiforme.

    PubMed

    Tabuchi, Sadaharu

    2015-01-01

    Glioblastoma multiforme (GBM) is the most malignant tumor of the central nervous system (CNS). Its prognosis is one of the worst among all cancer types, and it is considered a fatal malignancy, incurable with conventional therapeutic strategies. As the bioactive multifunctional lipid mediator lysophosphatidic acid (LPA) is well recognized to be involved in the tumorigenesis of cancers by acting on G-protein-coupled receptors, LPA receptor (LPAR) antagonists and LPA synthesis inhibitors have been proposed as promising drugs for cancer treatment. Six LPARs, named LPA1-6, are currently recognized. Among them, LPA1 is the dominant LPAR in the CNS and is highly expressed in GBM in combination with the overexpression of autotaxin (ATX), the enzyme (a phosphodiesterase, which is a potent cell motility-stimulating factor) that produces LPA.Invasion is a defining hallmark of GBM. LPA is significantly related to cell adhesion, cell motility, and invasion through the Rho family GTPases Rho and Rac. LPA1 is responsible for LPA-driven cell motility, which is attenuated by LPA4. GBM is among the most vascular human tumors. Although anti-angiogenic therapy (through the inhibition of vascular endothelial growth factor (VEGF)) was established, sufficient results have not been obtained because of the increased invasiveness triggered by anti-angiogenesis. As both ATX and LPA play a significant role in angiogenesis, similar to VEGF, inhibition of the ATX/LPA axis may be beneficial as a two-pronged therapy that includes anti-angiogenic and anti-invasion therapy. Conventional approaches to GBM are predominantly directed at cell proliferation. Recurrent tumors regrow from cells that have invaded brain tissues and are less proliferative, and are thus quite resistant to conventional drugs and radiation, which preferentially kill rapidly proliferating cells. A novel approach that targets this invasive subpopulation of GBM cells may improve the prognosis of GBM. Patients with GBM that

  5. Iodine(III)-Catalyzed Cascade Reactions Enabling a Direct Access to β-Lactams and α-Hydroxy-β-amino Acids.

    PubMed

    Patzelt, Christoph; Pöthig, Alexander; Gulder, Tanja

    2016-07-15

    In the presented method, a one-pot metal-free access to β-lactams is provided. The developed strategy employs a hypervalent iodine(III)-triggered bromination/rearrangement/cyclization cascade reaction that allows the straightforward synthesis of a broad range of structurally different lactams from cheap and easily available imides. This triple cascade reaction is furthermore extendable by an in situ ring-opening reaction, giving direct access to isoserine derivatives from simple imines in a four-step, one-pot reaction. PMID:27380445

  6. The cytochrome P450 2AA gene cluster in zebrafish (Danio rerio): Expression of CYP2AA1 and CYP2AA2 and response to phenobarbital-type inducers

    SciTech Connect

    Kubota, Akira; Bainy, Afonso C.D.; Woodin, Bruce R.; Goldstone, Jared V.; Stegeman, John J.

    2013-10-01

    The cytochrome P450 (CYP) 2 gene family is the largest and most diverse CYP gene family in vertebrates. In zebrafish, we have identified 10 genes in a new subfamily, CYP2AA, which does not show orthology to any human or other mammalian CYP genes. Here we report evolutionary and structural relationships of the 10 CYP2AA genes and expression of the first two genes, CYP2AA1 and CYP2AA2. Parsimony reconstruction of the tandem duplication pattern for the CYP2AA cluster suggests that CYP2AA1, CYP2AA2 and CYP2AA3 likely arose in the earlier duplication events and thus are most diverged in function from the other CYP2AAs. On the other hand, CYP2AA8 and CYP2AA9 are genes that arose in the latest duplication event, implying functional similarity between these two CYPs. A molecular model of CYP2AA1 showing the sequence conservation across the CYP2AA cluster reveals that the regions with the highest variability within the cluster map onto CYP2AA1 near the substrate access channels, suggesting differing substrate specificities. Zebrafish CYP2AA1 transcript was expressed predominantly in the intestine, while CYP2AA2 was most highly expressed in the kidney, suggesting differing roles in physiology. In the liver CYP2AA2 expression but not that of CYP2AA1, was increased by 1,4-bis [2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP) and, to a lesser extent, by phenobarbital (PB). In contrast, pregnenolone 16α-carbonitrile (PCN) increased CYP2AA1 expression, but not CYP2AA2 in the liver. The results identify a CYP2 subfamily in zebrafish that includes genes apparently induced by PB-type chemicals and PXR agonists, the first concrete in vivo evidence for a PB-type response in fish. - Highlights: • A tandemly duplicated cluster of ten CYP2AA genes was described in zebrafish. • Parsimony and duplication analyses suggest pathways to CYP2AA diversity. • Homology models reveal amino acid positions possibly related to functional diversity. • The CYP2AA locus does not share synteny with

  7. The AAS Workforce Survey

    NASA Astrophysics Data System (ADS)

    Postman, Marc; Norman, D. J.; Evans, N. R.; Ivie, R.

    2014-01-01

    The AAS Demographics Committee, on behalf of the AAS, was tasked with initiating a biennial survey to improve the Society's ability to serve its members and to inform the community about changes in the community's demographics. A survey, based in part on similar surveys for other scientific societies, was developed in the summer of 2012 and was publicly launched in January 2013. The survey randomly targeted 2500 astronomers who are members of the AAS. The survey was closed 4 months later (April 2013). The response rate was excellent - 63% (1583 people) completed the survey. I will summarize the results from this survey, highlighting key results and plans for their broad dissemination.

  8. AAS 227: Welcome!

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Greetings from the 227th American Astronomical Society meeting in Kissimmee, Florida! This week, along with several fellow authors from astrobites, Iwill bewritingupdates on selectedevents at themeeting and posting at the end of each day. You can follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.If youre an author or referee (or plan to be!) and youre here at the meeting, consider joining us at our Author and Referee Workshop on Wednesday in the Tallahassee room, where well be sharingsome of the exciting new features of the AAS journals. You can drop intoeither of the two-hour sessions(10 AM 12 PM or 1 PM 3 PM), and there will be afree buffet lunch at noon.Heres the agenda:Morning SessionTopic Speaker10:00 am 10:05 amIntroductionsJulie Steffen10:05 am 10:35 amChanges at AAS Journals; How to Be a Successful AAS AuthorEthan Vishniac10:35 am 11:00 amThe Peer Review ProcessButler Burton11:00 am 11:15 amAAS Nova: Sharing AAS Authors Research with the Broader CommunitySusanna Kohler11:15 am 11:30 amFixing Software and Instrumentation Publishing: New Paper Styles in AAS JournalsChris Lintott11:30 am 11:45 amMaking Article Writing Easier with the New AASTeX v6.0Greg Schwarz11:45 am 12:00 pmBringing JavaScript and Interactivity to Your AAS Journal FiguresGus MuenchLunch SessionTopic Speaker12:00 pm 12:15 pmUnified Astronomy ThesaurusKatie Frey12:15 pm 12:30 pmAAS/ADS ORCID Integration ToolAlberto Accomazzi12:30 pm 12:45 pmWorldWide Telescope and Video AbstractsJosh Peek12:45 pm 01:00 pmArizona Astronomical Data Hub (AADH)Bryan HeidornAfternoon SessionTopic Speaker01:00 pm 01:05 pmIntroductionsJulie Steffen01:05 pm 01:35 pmChanges at AAS Journals; How to Be a Successful AAS AuthorEthan Vishniac01:35 pm 02:00 pmThe Peer Review ProcessButler Burton02:00 pm 02:15 pmAAS Nova: Sharing AAS Authors Research with the Broader CommunitySusanna Kohler02:15 pm 02:30 pm

  9. AAS 228: Welcome!

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Greetings from the 228th American Astronomical Society meeting in San Diego, California! This week, along with a team of fellow authorsfrom astrobites, Iwill bewritingupdates on selectedevents at themeeting and posting twiceeach day. You can follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.If youre at the meeting, come stop by the AAS booth (Booth #211-213) to learn about the newly-announced partnership between AAS and astrobites and pick up some swag.And dont forget to visit the IOP booth in the Exhibit Hall (Booth #223) to learn more about the new corridors for AAS Journals and to pick up a badge pin to representyour corridor!

  10. OX1 orexin/hypocretin receptor signaling through arachidonic acid and endocannabinoid release.

    PubMed

    Turunen, Pauli M; Jäntti, Maria H; Kukkonen, Jyrki P

    2012-08-01

    We showed previously that OX(1) orexin receptor stimulation produced a strong (3)H overflow response from [(3)H]arachidonic acid (AA)-labeled cells. Here we addressed this issue with a novel set of tools and methods, to distinguish the enzyme pathways responsible for this response. CHO-K1 cells heterologously expressing human OX(1) receptors were used as a model system. By using selective pharmacological inhibitors, we showed that, in orexin-A-stimulated cells, the AA-derived radioactivity was released as two distinct components, i.e., free AA and the endocannabinoid 2-arachidonoyl glycerol (2-AG). Two orexin-activated enzymatic cascades are responsible for this response: cytosolic phospholipase A(2) (cPLA(2)) and diacylglycerol lipase; the former cascade is responsible for part of the AA release, whereas the latter is responsible for all of the 2-AG release and part of the AA release. Essentially only diacylglycerol released by phospholipase C but not by phospholipase D was implicated as a substrate for 2-AG production, although both phospholipases were strongly activated. The 2-AG released acted as a potent paracrine messenger through cannabinoid CB(1) receptors in an artificial cell-cell communication assay that was developed. The cPLA(2) cascade, in contrast, was involved in the activation of orexin receptor-operated Ca(2+) influx. 2-AG was also released upon OX(1) receptor stimulation in recombinant HEK-293 and neuro-2a cells. The results directly show, for the first time, that orexin receptors are able to generate potent endocannabinoid signals in addition to arachidonic acid signals, which may explain the proposed orexin-cannabinoid interactions (e.g., in neurons). PMID:22550093

  11. South Cascade Glacier bibliography

    SciTech Connect

    Fountain, A.G.; Fulk, M.A.

    1984-01-01

    South Cascade Glacier, in Washington State, resides in a well-defined basin with mainly unglacierized divides making it ideal for most glaciological and hydrological studies. This bibliography is divided into three cateogories: (1) studies done about South Cascade Glacier specifically; (2) studies that use data from South Cascade Glacier but do not focus on or give insight to the glacier itself; and (3) instrumentation studies and non-glacier projects including snow studies done in the basin. (ACR)

  12. Thermally cascaded thermoelectric generator

    NASA Technical Reports Server (NTRS)

    Flaherty, R.

    1970-01-01

    High efficiency thermoelectric generator utilizes a high-temperature thermoelectric material in thermal series with a low-temperature material. A thermally cascaded generator increases system efficiency.

  13. MAPK signaling triggers transcriptional induction of cFOS during amino acid limitation of HepG2 cells.

    PubMed

    Shan, Jixiu; Donelan, William; Hayner, Jaclyn N; Zhang, Fan; Dudenhausen, Elizabeth E; Kilberg, Michael S

    2015-03-01

    Amino acid (AA) deprivation in mammalian cells activates a collection of signaling cascades known as the AA response (AAR), which is characterized by transcriptional induction of stress-related genes, including FBJ murine osteosarcoma viral oncogene homolog (cFOS). The present study established that the signaling mechanism underlying the AA-dependent transcriptional regulation of the cFOS gene in HepG2 human hepatocellular carcinoma cells is independent of the classic GCN2-eIF2-ATF4 pathway. Instead, a RAS-RAF-MEK-ERK cascade mediates AAR signaling to the cFOS gene. Increased cFOS transcription is observed from 4-24 h after AAR-activation, exhibiting little or no overlap with the rapid and transient increase triggered by the well-known serum response. Furthermore, serum is not required for the AA-responsiveness of the cFOS gene and no phosphorylation of promoter-bound serum response factor (SRF) is observed. The ERK-phosphorylated transcription factor E-twenty six-like (p-ELK1) is increased in its association with the cFOS promoter after activation of the AAR. This research identified cFOS as a target of the AAR and further highlights the importance of AA-responsive MAPK signaling in HepG2 cells. PMID:25523140

  14. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induced P-450 mediated arachidonic acid (AA) metabolism in chick embryo liver (CEL) occurs in parenchymal cells (PC) rather than in non-parenchymal cells (NPC)

    SciTech Connect

    Paroli, L.; Rifkind, A.B. )

    1992-02-26

    TCDD induces cytochrome P-450 mediated AA metabolism in CEL and changes the dominant metabolite(s) from {omega}-OH AA to AA epoxygenase products (EETs and EET-diols). PC and NPC from CEL were separated by differential centrifugation and characterized by morphology, immunohistochemistry and P-450 mediated xenobiotic metabolism; purities were >95%. PC and NPC, from 16 day old chick embryos treated for 5 days with TCDD or vehicle alone, were cultured for 48 hr, homogenized and incubated with ({sup 14}C)-AA {plus minus} NADPH. AA products were resolved by reverse phase HPLC. The major product in control PC, {omega}-OH AA was not significantly affected by TCDD. All of the AA metabolism was NADPH dependent. Control and TCDD treated PC had the same metabolite patterns as whole liver microsomes. Neither control nor TCDD treated NPC generated P-450 AA metabolites. Also co-culturing NPC with PC did not affect AA metabolism of either cell type. The findings indicate that TCDD-induced changes in AA metabolism are retained in culture and that hepatocytes rather than NPC effect P-450 mediated AA metabolism in both control and TCDD-induced CEL.

  15. Activity of vegetative insecticidal proteins Vip3Aa58 and Vip3Aa59 of Bacillus thuringiensis against lepidopteran pests.

    PubMed

    Baranek, Jakub; Kaznowski, Adam; Konecka, Edyta; Naimov, Samir

    2015-09-01

    Vegetative insecticidal proteins (Vips) secreted by some isolates of Bacillus thuringiensis show activity against insects and are regarded as insecticides against pests. A number of B. thuringiensis strains harbouring vip3A genes were isolated from different sources and identified by using a PCR based approach. The isolates with the highest insecticidal activity were indicated in screening tests, and their vip genes were cloned and sequenced. The analysis revealed two polymorphic Vip protein forms, which were classified as Vip3Aa58 and Vip3Aa59. After expression of the vip genes, the proteins were isolated and characterized. The activity of both toxins was estimated against economically important lepidopteran pests of woodlands (Dendrolimus pini), orchards (Cydia pomonella) and field crops (Spodoptera exigua). Vip3Aa58 and Vip3Aa59 were highly toxic and their potency surpassed those of many Cry proteins used in commercial bioinsecticides. Vip3Aa59 revealed similar larvicidal activity as Vip3Aa58 against S. exigua and C. pomonella. Despite 98% similarity of amino acid sequences of both proteins, Vip3Aa59 was significantly more active against D. pini. Additionally the effect of proteolytic activation of Vip58Aa and Vip3Aa59 on toxicity of D. pini and S. exigua was studied. Both Vip3Aa proteins did not show any activity against Tenebrio molitor (Coleoptera) larvae. The results suggest that the Vip3Aa58 and Vip3Aa59 toxins might be useful for controlling populations of insect pests of crops and forests. PMID:26146224

  16. Cascaded automatic target recognition (Cascaded ATR)

    NASA Astrophysics Data System (ADS)

    Walls, Bradley

    2010-04-01

    The global war on terror has plunged US and coalition forces into a battle space requiring the continuous adaptation of tactics and technologies to cope with an elusive enemy. As a result, technologies that enhance the intelligence, surveillance, and reconnaissance (ISR) mission making the warfighter more effective are experiencing increased interest. In this paper we show how a new generation of smart cameras built around foveated sensing makes possible a powerful ISR technique termed Cascaded ATR. Foveated sensing is an innovative optical concept in which a single aperture captures two distinct fields of view. In Cascaded ATR, foveated sensing is used to provide a coarse resolution, persistent surveillance, wide field of view (WFOV) detector to accomplish detection level perception. At the same time, within the foveated sensor, these detection locations are passed as a cue to a steerable, high fidelity, narrow field of view (NFOV) detector to perform recognition level perception. Two new ISR mission scenarios, utilizing Cascaded ATR, are proposed.

  17. AAS Career Services

    NASA Astrophysics Data System (ADS)

    Marvel, Kevin B.

    2012-08-01

    The American Astronomical Society provides substantial programs in the area of Career Services.Motivated by the Society's mission to enhance and share humanity's understanding of the Universe, the AAS provides a central resource for advertising positions, interviewing opportunities at its annual winter meeting and information, workshops and networks to enable astronomers to find employment.The programs of the Society in this area are overseen by an active committee on employment and the AAS Council itself.Additional resources that help characterize the field, its growth and facts about employment such as salaries and type of jobs available are regularly summarized and reported on by the American Institute of Physics.

  18. Theory of cascade refrigeration

    NASA Astrophysics Data System (ADS)

    Quack, Hans H.

    2012-06-01

    The maximum difference between the warm and cold temperature of a refrigeration cycle is limited by properties of the refrigerant and/or losses associated with the transport of the refrigerant. For larger temperature differences, one has to arrange several refrigeration cycles "above" each other, each cycle spanning a certain temperature difference. This approach is called cascade refrigeration and has played an important role in the history of cryogenics. For a theory of cascade refrigeration it is helpful to define a general one-stage non-reversible refrigeration step and to visualize it within the temperature-entropy diagram. Then one can combine several one-stage cycles to a cascade. There exist two types of cascades: "Full" cascades, where all entropy gains of a lower stage are transferred to the next higher temperature stage, and "partial" cascades, where each single cycle goes up to ambient temperature, where a part of the entropy gain is removed, and only the rest of the entropy gain is transferred to the next higher temperature stage. In cryogenic refrigeration "partial" cascades are generally more efficient than "full" cascades.

  19. The 9aaTAD Transactivation Domains: From Gal4 to p53.

    PubMed

    Piskacek, Martin; Havelka, Marek; Rezacova, Martina; Knight, Andrea

    2016-01-01

    The family of the Nine amino acid Transactivation Domain, 9aaTAD family, comprises currently over 40 members. The 9aaTAD domains are universally recognized by the transcriptional machinery from yeast to man. We had identified the 9aaTAD domains in the p53, Msn2, Pdr1 and B42 activators by our prediction algorithm. In this study, their competence to activate transcription as small peptides was proven. Not surprisingly, we elicited immense 9aaTAD divergence in hundreds of identified orthologs and numerous examples of the 9aaTAD species' convergence. We found unforeseen similarity of the mammalian p53 with yeast Gal4 9aaTAD domains. Furthermore, we identified artificial 9aaTAD domains generated accidentally by others. From an evolutionary perspective, the observed easiness to generate 9aaTAD transactivation domains indicates the natural advantage for spontaneous generation of transcription factors from DNA binding precursors. PMID:27618436

  20. Label-free and ratiometric detection of nuclei acids based on graphene quantum dots utilizing cascade amplification by nicking endonuclease and catalytic G-quadruplex DNAzyme.

    PubMed

    Wang, Guang-Li; Fang, Xin; Wu, Xiu-Ming; Hu, Xue-Lian; Li, Zai-Jun

    2016-07-15

    Herein, we report a ratiometric fluorescence assay based on graphene quantum dots (GQDs) for the ultrasensitive DNA detection by coupling the nicking endonuclease assisted target recycling and the G-quadruplex/hemin DNAzyme biocatalysis for cascade signal amplifications. With o-phenylenediamine acted as the substrate of G-quadruplex/hemin DNAzyme, whose oxidization product (that is, 2,3-diaminophenazine, DAP) quenched the fluorescence intensity of GQDs (at 460nm) obviously, accompanied with the emergence of a new emission of DAP (at 564nm). The ratiometric signal variations at the emission wavelengths of 564 and 460nm (I564/I460) were utilized for label-free, sensitive, and selective detection of target DNA. Utilizing the nicking endonuclease assisted target recycling and the G-quadruplex/hemin DNAzyme biocatalysis for amplified cascade generation of DAP, the proposed bioassay exhibited high sensitivity toward target DNA with a detection limit of 30fM. The method also had additional advantages such as facile preparation and easy operation. PMID:26950646

  1. AAS Oral History Project

    NASA Astrophysics Data System (ADS)

    Buxner, Sanlyn; Holbrook, Jarita; AAS Oral History Team

    2016-06-01

    Now in its fourth year, the AAS Oral History Project has interviewed over 80 astronomers from all over the world. Led by the AAS Historical Astronomy Division (HAD) and partially funded by the American Institute of Physics Niels Bohr Library and ongoing support from the AAS, volunteers have collected oral histories from astronomers at professional meetings starting in 2015, including AAS, DPS, and the IAU general assembly. Each interview lasts one and a half to two hours and focuses on interviewees’ personal and professional lives. Questions include those about one’s family, childhood, strong influences on one’s scientific career, career path, successes and challenges, perspectives on how astronomy is changing as a field, and advice to the next generation. Each interview is audio recorded and transcribed, the content of which is checked with each interviewee. Once complete, interview transcripts are posted online as part of a larger oral history library at https://www.aip.org/history-programs/niels-bohr-library/oral-histories. Future analysis will reveal a rich story of astronomers and will help the community address issues of diversity, controversies, and the changing landscape of science. We are still recruiting individuals to be interviewed from all stages of career from undergraduate students to retired and emeritus astronomers. Contact Jarita Holbrook to schedule an interview or to find out more information about the project (astroholbrook@gmail.com). Also, contact Jarita Holbrook if you would like to become an interviewer for the project.

  2. American Astronomical Society (AAS)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Founded in 1899, the AAS is a non-profit scientific society created to promote the advancement of astronomy and closely related branches of science. Its membership consists primarily of professional researchers in the astronomical sciences, but also includes educators, students and others interested in the advancement of astronomical research. About 85% of the membership is drawn from North Ame...

  3. 5. VIEW OF UPPER AND LOWER CASCADE BRIDGES AND CASCADE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF UPPER AND LOWER CASCADE BRIDGES AND CASCADE CREEK FROM 100 YARDS WEST OF THE ROSTRUM (ROCK FORMATION ON SOUTH SIDE OF MERCED RIVER). HIGHWAY 140 IS AT BOTTOM OF FRAME. HIGHWAY 120, THE BIG OAK FLAT ROAD CROSSES FRAME JUST ABOVE CENTER. - Cascade Creek Bridge, Spanning Cascade Creek on New Big Oak Flat Road, Yosemite Village, Mariposa County, CA

  4. Lipoxygenase Pathway in Islet Endocrine Cells. OXIDATIVE METABOLISM OF ARACHIDONIC ACID PROMOTES INSULIN RELEASE

    PubMed Central

    Metz, Stewart; VanRollins, Michael; Strife, Robert; Fujimoto, Wilfred; Robertson, R. Paul

    1983-01-01

    , diethylmaleate (which binds intracellular glutathione and thereby impedes conversion of the lipoxygenase intermediates hydroperoxy-ETE and leukotriene A4 to HETE and leukotriene C4, respectively) potentiated the effect of glucose and of exogenous AA. Finally, 5,6-epoxy, 8,11,14-eicosatrienoic acid (a relatively stable epoxide analogue of leukotriene A4) as well as two other epoxy-analogues, potentiated glucose-induced insulin release. We conclude that dual pathways of AA metabolism exist in islet endocrine cells and have opposing regulatory effects on the beta cell—an inhibitory cyclooxygenase cascade and a stimulatory lipoxygenase cascade. Labile products of the latter pathway may play a pivotal role in stimulus-secretion coupling in the islet. Images PMID:6406544

  5. Differential Ratios of Omega Fatty Acids (AA/EPA+DHA) Modulate Growth, Lipid Peroxidation and Expression of Tumor Regulatory MARBPs in Breast Cancer Cell Lines MCF7 and MDA-MB-231

    PubMed Central

    Mansara, Prakash P.; Deshpande, Rashmi A.; Vaidya, Milind M.; Kaul-Ghanekar, Ruchika

    2015-01-01

    Omega 3 (n3) and Omega 6 (n6) polyunsaturated fatty acids (PUFAs) have been reported to exhibit opposing roles in cancer progression. Our objective was to determine whether different ratios of n6/n3 (AA/EPA+DHA) FAs could modulate the cell viability, lipid peroxidation, total cellular fatty acid composition and expression of tumor regulatory Matrix Attachment Region binding proteins (MARBPs) in breast cancer cell lines and in non-cancerous, MCF10A cells. Low ratios of n6/n3 (1:2.5, 1:4, 1:5, 1:10) FA decreased the viability and growth of MDA-MB-231 and MCF7 significantly compared to the non-cancerous cells (MCF10A). Contrarily, higher n6/n3 FA (2.5:1, 4:1, 5:1, 10:1) decreased the survival of both the cancerous and non-cancerous cell types. Lower ratios of n6/n3 selectively induced LPO in the breast cancer cells whereas the higher ratios induced in both cancerous and non-cancerous cell types. Interestingly, compared to higher n6/n3 FA ratios, lower ratios increased the expression of tumor suppressor MARBP, SMAR1 and decreased the expression of tumor activator Cux/CDP in both breast cancer and non-cancerous, MCF10A cells. Low n6/n3 FAs significantly increased SMAR1 expression which resulted into activation of p21WAF1/CIP1 in MDA-MB-231 and MCF7, the increase being ratio dependent in MDA-MB-231. These results suggest that increased intake of n3 fatty acids in our diet could help both in the prevention as well as management of breast cancer. PMID:26325577

  6. Exploring the Effects of Omega-3 and Omega-6 Fatty Acids on Allergy Using a HEK-Blue Cell Line

    PubMed Central

    Ahmed, Nayyar; Barrow, Colin J.; Suphioglu, Cenk

    2016-01-01

    Background: Allergic reactions can result in life-threatening situations resulting in high economic costs and morbidity. Therefore, more effective reagents are needed for allergy treatment. A causal relationship has been suggested to exist between the intake of omega-3/6 fatty acids, such as docosahexanoic acid (DHA), eicosapentanoic acid (EPA), docosapentanoic acid (DPA) and arachidonic acid (AA), and atopic individuals suffering from allergies. In allergic cascades, the hallmark cytokine IL-4 bind to IL-4 receptor (IL-4R) and IL-13 binds to IL-13 receptor (IL-13R), this activates the STAT6 phosphorylation pathway leading to gene activation of allergen-specific IgE antibody production by B cells. The overall aim of this study was to characterize omega-3/6 fatty acids and their effects on STAT6 signaling pathway that results in IgE production in allergic individuals. Methods: The fatty acids were tested in vitro with a HEK-Blue IL-4/IL-13 reporter cell line model, transfected with a reporter gene that produces an enzyme, secreted embryonic alkaline phosphatase (SEAP). SEAP acts as a substitute to IgE when cells are stimulated with bioactive cytokines IL-4 and/or IL-13. Results: We have successfully used DHA, EPA and DPA in our studies that demonstrated a decrease in SEAP secretion, as opposed to an increase in SEAP secretion with AA treatment. A statistical Student’s t-test revealed the significance of the results, confirming our initial hypothesis. Conclusion: We have successfully identified and characterised DHA, EPA, DPA and AA in our allergy model. While AA was a potent stimulator, DHA, EPA and DPA were potential inhibitors of IL-4R/IL-13R signalling, which regulates the STAT6 induced pathway in allergic cascades. Such findings are significant in the future design of dietary therapeutics for the treatment of allergies. PMID:26861314

  7. Unsteady Euler cascade analysis

    NASA Technical Reports Server (NTRS)

    Liu, Jong-Shang; Sockol, Peter M.

    1989-01-01

    The results of an investigation of the rotor-stator interaction phenomena in turbomachines are presented. Numerical study was carried out by solving the unsteady Euler equations in the blade-to-blade direction for a variety of cascade geometries. The problem of uneven rotor and stator blades is addressed by adopting the tilted time domain technique. Computed solutions are presented and discussed for a NACA 0012 type cascade and the first stage fuel turbopump of the Space Shuttle Main Engine (SSME).

  8. The nitrogen cascade

    SciTech Connect

    Galloway J.N.; Aber J.D.; Erisman J.W.; Seitzinger S.P.; Howarth R.W.; Cowling E.B.; Cosby B.J.

    2003-04-01

    Human production of food and energy is the dominant continental process that breaks the triple bond in molecular nitrogen (N{sub 2}) and creates reactive nitrogen (Nr) species. Circulation of anthropogenic Nr in Earth's atmosphere, hydrosphere, and biosphere has a wide variety of consequences, which are magnified with time as Nr moves along its biogeochemical pathway. The same atom of Nr can cause multiple effects in the atmosphere, in terrestrial ecosystems, in freshwater and marine systems, and on human health. We call this sequence of effects the nitrogen cascade. As the cascade progresses, the origin of Nr becomes unimportant. Reactive nitrogen does not cascade at the same rate through all environmental systems; some systems have the ability to accumulate Nr, which leads to lag times in the continuation of the cascade. These lags slow the cascade and result in Nr accumulation in certain reservoirs, which in turn can enhance the effects of Nr on that environment. The only way to eliminate Nr accumulation and stop the cascade is to convert Nr back to nonreactive N{sub 2}.

  9. The accurate determination of bismuth in lead concentrates and other non-ferrous materials by AAS after separation and preconcentration of the bismuth with mercaptoacetic acid.

    PubMed

    Howell, D J; Dohnt, B R

    1982-05-01

    A method for determining 0.0001% and upwards of bismuth in lead, zinc or copper concentrates, metals or alloys and other smelter residues is described. Bismuth is separated from lead, iron and gangue materials with mercaptoacetic acid after reduction of the iron with hydrazine. Large quantities of tin can be removed during the dissolution. An additional separation is made for materials high in copper and/or sulphate. The separated and concentrated bismuth is determined by atomic-absorption spectrometry using the Bi line at 223.1 nm. The proposed method also allows the simultaneous separation and determination of silver. PMID:18963145

  10. Tracking Earthquake Cascades

    NASA Astrophysics Data System (ADS)

    Jordan, T. H.

    2011-12-01

    In assessing their risk to society, earthquakes are best characterized as cascades that can propagate from the natural environment into the socio-economic (built) environment. Strong earthquakes rarely occur as isolated events; they usually cluster in foreshock-mainshock-aftershock sequences, seismic swarms, and extended sequences of large earthquakes that propagate along major fault systems. These cascades are regulated by stress-mediated interactions among faults driven by tectonic loading. Within these cascades, each large event can itself cause a chain reaction in which the primary effects of faulting and ground shaking induce secondary effects, including tsunami, landslides, liquefaction, and set off destructive processes within the built environment, such as fires and radiation leakage from nuclear plants. Recent earthquakes have demonstrated how the socio-economic effects of large earthquakes can reverberate for many years. To reduce earthquake risk and improve the resiliency of communities to earthquake damage, society depends on five geotechnologies for tracking earthquake cascades: long-term probabilistic seismic hazard analysis (PSHA), short-term (operational) earthquake forecasting, earthquake early warning, tsunami warning, and the rapid production of post-event information for response and recovery (see figure). In this presentation, I describe how recent advances in earthquake system science are leading to improvements in this geotechnology pipeline. In particular, I will highlight the role of earthquake simulations in predicting strong ground motions and their secondary effects before and during earthquake cascades

  11. AAS 227: Day 1

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or at astrobites.com, or catch ourlive-tweeted updates from the @astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Things kicked off last night at our undergraduate reception booth. Thanks to all of you who stopped by we were delightedto have so many people tell us that they already know about and useastrobites, and we were excited to introduce a new cohort of students at AAS to astrobites for the first time.Tuesday morning was the official start of the meeting. Here are just a few of the talks and workshops astrobiters attended today.Opening Address (by Becky Smethurst)The President of the AAS, aka our fearless leader Meg Urry kicked off the meeting this morning at the purely coffee powered hour of 8am this morning. She spoke about the importance of young astronomers at the meeting (heres looking at you reader!) and also the importance of the new Working Group for Accessibility and Disabilities (aka WGAD pronounced like wicked) at the AAS. The Society has made extra effort this year to make the conference accessible to all,a message which was very well received by everyone in attendance.Kavli Lecture: New Horizons Alan Stern (by Becky Smethurst)We were definitely spoilt with the first Plenary lecture at this years conference Alan Stern gave us a a review of the New Horizons mission of the Pluto Fly By (astrobites covered the mission back in July with this post). We were treated to beautiful images, wonderful results and a foray into geology.Before (Hubble) and after #NewHorizons. #thatisall #science #astro alanstern #aas227 pic.twitter.com/kkMt6RsSIR Science News (@topsciencething) January 5, 2016Some awesome facts from the lecture that blew my mind:New Horizons is now 2AU (!) beyond Pluto

  12. Resonant Cascaded Downconversion

    SciTech Connect

    Weedbrook, Christian; Parrett, Ben; Kheruntsyan, Karen; Drummond, Peter; Pooser, Raphael C; Pfister, Olivier

    2012-01-01

    We analyze an optical parametric oscillator (OPO) in which cascaded down-conversion occurs inside a cavity resonant for all modes but the initial pump. Due to the resonant cascade design, the OPO presents two {chi}{sup (2)}-level oscillation thresholds that are therefore much lower than for a {chi}{sup (3)} OPO. This is promising for reaching the regime of an effective third-order nonlinearity well above both thresholds. Such a {chi}{sup (2)} cascaded device also has potential applications in frequency conversion to far-infrared regimes. But, most importantly, it can generate novel multipartite quantum correlations in the output radiation, which represent a step beyond squeezed or entangled light. The output can be highly non-Gaussian and therefore not describable by any semiclassical model. In this paper, we derive quantum stochastic equations in the positive-P representation and undertake an analysis of steady-state and dynamical properties of this system.

  13. Hadron cascades produced by electromagnetic cascades

    SciTech Connect

    Nelson, W.R.; Jenkins, T.M.; Ranft, J.

    1986-12-01

    A method for calculating high energy hadron cascades induced by multi-GeV electron and photon beams is described. Using the EGS4 computer program, high energy photons in the EM shower are allowed to interact hadronically according to the vector meson dominance (VMD) model, facilitated by a Monte Carlo version of the dual multistring fragmentation model which is used in the hadron cascade code FLUKA. The results of this calculation compare very favorably with experimental data on hadron production in photon-proton collisions and on the hadron production by electron beams on targets (i.e., yields in secondary particle beam lines). Electron beam induced hadron star density contours are also presented and are compared with those produced by proton beams. This FLUKA-EGS4 coupling technique could find use in the design of secondary beams, in the determination high energy hadron source terms for shielding purposes, and in the estimation of induced radioactivity in targets, collimators and beam dumps.

  14. Collisional Cascades Revisited

    NASA Astrophysics Data System (ADS)

    Schlichting, Hilke; Pan, M.

    2013-01-01

    Collisional cascades are believed to be the primary mechanism operating in circumstellar dusty debris disks, and are thought to be important in the Kuiper and Asteroid belt. Collisional cascades transfer mass via destructive collisions from larger bodies to smaller ones. Their widespread occurrence and potential importance in understanding planet formation and planet-disk interactions have motivated detailed studies of collisional cascades. The standard theoretical treatment of collisional cascades derives a steady-state size distribution assuming a single constant velocity dispersion for all bodies regardless of size. We relax this assumption and solve self-consistently for the bodies' steady-state size and size-dependent velocity distributions. Specifically, we account for viscous stirring, dynamical friction, and collisional damping of the bodies' random velocities in addition to the mass conservation requirement typically applied to find the size distribution in a steady-state cascade. The resulting size distributions are significantly steeper than those derived without velocity evolution. For example, accounting self-consistently for the velocities can change the standard q = 3.5 power-law index of the Dohnanyi differential size spectrum to an index as large as q = 4. Similarly, for bodies held together by their own gravity, the corresponding power-law index range 2.88 < q < 3.14 of Pan & Sari (2005) can steepen to values as large as q = 3.26. These differences in the size distribution power law index are very important when estimating the total disk mass, including larger bodies, by extrapolating from the observed dust masses. Our velocity results allow quantitative predictions of the bodies' scale heights as a function of size. Together with our predictions, observations of the scale heights for different-sized bodies in, for example, extrasolar debris disks may constrain the total mass in large bodies stirring the cascade as well as the colliding bodies

  15. Intra Nucleon Cascade Program

    1998-08-18

    The package consists of three programs ISABEL, EVA, and PACE-2. ISABEL and PACE-2 are part of the LAHET code. ISABEL is an intra-nucleon cascade program. The output cascades are used as directly as input files to the two evaporation programs EVA and PACE-2. EVA ignores the effect of the angular momentum of the excited nuclei on the deexcitation and also ignores the possibility of gamma emission as long as particle emission is energetically allowed. PACE-2more » takes full account of angular momentum effects including irast levels and gamma emission at all stages of the evaporation chain.« less

  16. Strategic Change in AAS Publishing

    NASA Astrophysics Data System (ADS)

    Steffen, Julie

    2015-08-01

    The American Astronomical Society has embarked on a process of strategic change in its publishing program. The process has incuded authors, AAS leaders, editors, publishing experts, librarians, and data scientists. This session will outline the still ongoing process and present some both upcoming and already available new AAS Publishing features and services to the global astronomy community.

  17. 'Cascade Gold' raspberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cascade Gold’ is a new gold fruited, floricane fruiting raspberry cultivar (Rubus idaeus L.) jointly released by Washington State University (WSU), Oregon State University (OSU) and the U.S. Department of Agriculture (USDA). It has been evaluated at Puyallup, Wash. in plantings from 1988 to 2008. ...

  18. Howling about Trophic Cascades

    ERIC Educational Resources Information Center

    Kowalewski, David

    2012-01-01

    Following evolutionary theory and an agriculture model, ecosystem research has stressed bottom-up dynamics, implying that top wild predators are epiphenomenal effects of more basic causes. As such, they are assumed expendable. A more modern co-evolutionary and wilderness approach--trophic cascades--instead suggests that top predators, whose…

  19. Cascaded thermoacoustic devices

    DOEpatents

    Swift, Gregory W.; Backhaus, Scott N.; Gardner, David L.

    2003-12-09

    A thermoacoustic device is formed with a resonator system defining at least one region of high specific acoustic impedance in an acoustic wave within the resonator system. A plurality of thermoacoustic units are cascaded together within the region of high specific acoustic impedance, where at least one of the thermoacoustic units is a regenerator unit.

  20. AAS 227: Day 2

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Welcome to Day 2 of the winter American Astronomical Society (AAS) meeting in Kissimmee! Several of us are attending the conference this year, and we will report highlights from each day here on astrobites. If youd like to see more timely updates during the day, we encourage you to follow @astrobites on twitter or search the #aas227 hashtag.Plenary Session: Black Hole Physics with the Event Horizon Telescope (by Susanna Kohler)If anyone needed motivation to wake up early this morning, they got it in the form of Feryal Ozel (University of Arizona) enthralling us all with exciting pictures, videos, and words about black holes and the Event Horizon Telescope. Ozel spoke to a packed room (at 8:30am!) about where the project currently stands, and where its heading in the future.The EHT has pretty much the coolest goal ever: actually image the event horizons of black holes in our universe. The problem is that the largest black hole we can look at (Sgr A*, in the center of our galaxy) has an event horizon size of 50 as. For this kind of resolution roughly equivalent to trying to image a DVD on the Moon! wed need an Earth-sized telescope. EHT has solved this problem by linking telescopes around the world, creating one giant, mm-wavelength effective telescope with a baseline the size of Earth.Besides producing awesome images, the EHT will be able to test properties of black-hole spacetime, the no-hair theorem, and general relativity (GR) in new regimes.Ozel walked us through some of the theory prep work we need to do now in order to get the most science out of the EHT, including devising new

  1. Integrated Broadband Quantum Cascade Laser

    NASA Technical Reports Server (NTRS)

    Mansour, Kamjou (Inventor); Soibel, Alexander (Inventor)

    2016-01-01

    A broadband, integrated quantum cascade laser is disclosed, comprising ridge waveguide quantum cascade lasers formed by applying standard semiconductor process techniques to a monolithic structure of alternating layers of claddings and active region layers. The resulting ridge waveguide quantum cascade lasers may be individually controlled by independent voltage potentials, resulting in control of the overall spectrum of the integrated quantum cascade laser source. Other embodiments are described and claimed.

  2. AAS 227: Day 2

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Welcome to Day 2 of the winter American Astronomical Society (AAS) meeting in Kissimmee! Several of us are attending the conference this year, and we will report highlights from each day here on astrobites. If youd like to see more timely updates during the day, we encourage you to follow @astrobites on twitter or search the #aas227 hashtag.Plenary Session: Black Hole Physics with the Event Horizon Telescope (by Susanna Kohler)If anyone needed motivation to wake up early this morning, they got it in the form of Feryal Ozel (University of Arizona) enthralling us all with exciting pictures, videos, and words about black holes and the Event Horizon Telescope. Ozel spoke to a packed room (at 8:30am!) about where the project currently stands, and where its heading in the future.The EHT has pretty much the coolest goal ever: actually image the event horizons of black holes in our universe. The problem is that the largest black hole we can look at (Sgr A*, in the center of our galaxy) has an event horizon size of 50 as. For this kind of resolution roughly equivalent to trying to image a DVD on the Moon! wed need an Earth-sized telescope. EHT has solved this problem by linking telescopes around the world, creating one giant, mm-wavelength effective telescope with a baseline the size of Earth.Besides producing awesome images, the EHT will be able to test properties of black-hole spacetime, the no-hair theorem, and general relativity (GR) in new regimes.Ozel walked us through some of the theory prep work we need to do now in order to get the most science out of the EHT, including devising new

  3. AAS 227: Day 1

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or at astrobites.com, or catch ourlive-tweeted updates from the @astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Things kicked off last night at our undergraduate reception booth. Thanks to all of you who stopped by we were delightedto have so many people tell us that they already know about and useastrobites, and we were excited to introduce a new cohort of students at AAS to astrobites for the first time.Tuesday morning was the official start of the meeting. Here are just a few of the talks and workshops astrobiters attended today.Opening Address (by Becky Smethurst)The President of the AAS, aka our fearless leader Meg Urry kicked off the meeting this morning at the purely coffee powered hour of 8am this morning. She spoke about the importance of young astronomers at the meeting (heres looking at you reader!) and also the importance of the new Working Group for Accessibility and Disabilities (aka WGAD pronounced like wicked) at the AAS. The Society has made extra effort this year to make the conference accessible to all,a message which was very well received by everyone in attendance.Kavli Lecture: New Horizons Alan Stern (by Becky Smethurst)We were definitely spoilt with the first Plenary lecture at this years conference Alan Stern gave us a a review of the New Horizons mission of the Pluto Fly By (astrobites covered the mission back in July with this post). We were treated to beautiful images, wonderful results and a foray into geology.Before (Hubble) and after #NewHorizons. #thatisall #science #astro alanstern #aas227 pic.twitter.com/kkMt6RsSIR Science News (@topsciencething) January 5, 2016Some awesome facts from the lecture that blew my mind:New Horizons is now 2AU (!) beyond Pluto

  4. AAS 227: Day 3

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Welcome to Day 3 of the winter American Astronomical Society (AAS) meeting in Kissimmee! Several of us are attending the conference this year, and we will report highlights from each day here on astrobites. If youd like to see more timely updates during the day, we encourage you to follow @astrobites on twitter or search the #aas227 hashtag.Henry Norris Russell Lecture: Viewing the Universe with Infrared Eyes: The Spitzer Space Telescope (by Erika Nesvold)The Henry Norris Russell Award is the highest honor given by the AAS, for a lifetime of eminence in astronomy research. This years award went to Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics. Fazio became a leader in gamma ray astronomy before switching mid-career to the study of infrared astronomy, and he gave his award lecture on the latter subject, specifically on the Spitzer Space Telescope, one of the most successful infrared telescopes of all time.Artists rendering of the Spitzer space telescope. [NASA/JPL-Caltech]Spitzer has been operating for more than twelve years, and has resulted in over six thousand papers in refereed journals in that time. The telescope sits in an Earth-trailing orbit around the Sun, and is now farther from the Earth (1.4 AU) than the Earth is from the Sun. Fazio gave the audience a fascinating overview of the science done by Spitzer over more than a decade. One of the most productive areas of research for Spitzer is the study of exoplanets, which hadnt even been discovered when the Spitzer Telescope was first conceived. Spitzers high sensitivity and ability to observe exoplanets over

  5. Bacterial cellulose based hydrogel (BC-g-AA) and preliminary result of swelling behavior

    NASA Astrophysics Data System (ADS)

    Hakam, Adil; Lazim, Azwan Mat; Abdul Rahman, I. Irman

    2013-11-01

    In this study, hydrogel based on Bacterial cellulose (BC) or local known as Nata de Coco, which grafted with monomer: Acrylic acid (AA) is synthesis by using gamma radiation technique. These hydrogel (BC-g-AA) has unique characteristic whereby responsive to pH buffer solution.

  6. Bacterial cellulose based hydrogel (BC-g-AA) and preliminary result of swelling behavior

    SciTech Connect

    Hakam, Adil; Lazim, Azwan Mat; Abdul Rahman, I. Irman

    2013-11-27

    In this study, hydrogel based on Bacterial cellulose (BC) or local known as Nata de Coco, which grafted with monomer: Acrylic acid (AA) is synthesis by using gamma radiation technique. These hydrogel (BC-g-AA) has unique characteristic whereby responsive to pH buffer solution.

  7. AAS 227: Day 3

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Welcome to Day 3 of the winter American Astronomical Society (AAS) meeting in Kissimmee! Several of us are attending the conference this year, and we will report highlights from each day here on astrobites. If youd like to see more timely updates during the day, we encourage you to follow @astrobites on twitter or search the #aas227 hashtag.Henry Norris Russell Lecture: Viewing the Universe with Infrared Eyes: The Spitzer Space Telescope (by Erika Nesvold)The Henry Norris Russell Award is the highest honor given by the AAS, for a lifetime of eminence in astronomy research. This years award went to Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics. Fazio became a leader in gamma ray astronomy before switching mid-career to the study of infrared astronomy, and he gave his award lecture on the latter subject, specifically on the Spitzer Space Telescope, one of the most successful infrared telescopes of all time.Artists rendering of the Spitzer space telescope. [NASA/JPL-Caltech]Spitzer has been operating for more than twelve years, and has resulted in over six thousand papers in refereed journals in that time. The telescope sits in an Earth-trailing orbit around the Sun, and is now farther from the Earth (1.4 AU) than the Earth is from the Sun. Fazio gave the audience a fascinating overview of the science done by Spitzer over more than a decade. One of the most productive areas of research for Spitzer is the study of exoplanets, which hadnt even been discovered when the Spitzer Telescope was first conceived. Spitzers high sensitivity and ability to observe exoplanets over

  8. Cascaded humidified advanced turbine

    SciTech Connect

    Nakhamkin, M.; Swenson, E.C.; Cohn, A.; Bradshaw, D.; Taylor, R.; Wilson, J.M.; Gaul, G.; Jahnke, F.; Polsky, M.

    1995-05-01

    This article describes how, by combining the best features of simple- and combined-cycle gas turbine power plants, the CHAT cycle concept offers power producers a clean, more efficient and less expensive alternative to both. The patented cascaded advanced turbine and its cascaded humidified advanced turbine (CHAT) derivative offer utilities and other power producers a practical advanced gas turbine power plant by combining commercially-available gas turbine and industrial compressor technologies in a unique way. Compared to combined-cycle plants, a CHAT power plant has lower emissions and specific capital costs-approximately 20 percent lower than what is presently available. Further, CHAT`s operating characteristics are especially well-suited to load following quick start-up scenarios and they are less susceptible to power degradation from higher ambient air temperature conditions.

  9. AAS 228: Day 4

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note: Lastweek we were at the 228th AAS Meeting in San Diego, CA. Here is a final post aboutselectedevents on the last day of the meeting, written by authors fromastrobites.com, a grad-student collaborative project with which we recently announced a new partnership! Starting in July,keep an eye out for astrobites postsat AAS Nova in between Highlights(i.e., on Tuesdays and Thursdays).Were excited to be working together to bring you more recent astronomy research from AAS journals!Extrasolar Planets: Detection (by Leonardo dos Santos)Thursdays first session on exoplanets was about detecting these distant worlds, and the opening talk was given by Robert Siverd (Las Cumbres Observatory). He describes the NRES, a network of spectrographs that will look for exoplanets using the radial velocity method. One of the coolest aspects of this instrument is that it will feature an on the fly scheduling system that will perform observations as efficiently as possible. The spectrograph is still being tested, but a unit will be deployed at CTIO later this year.@lcogt contracted by @NASA_TESS for follow up of their candidates. #aas228 Jessie Christiansen (@aussiastronomer) June 16, 2016Measuring the depths of transits and eclipses in Spitzer has been problematic in the past, since the Spitzer instrument IRAC (InfraRed Array Camera) has a non-uniform response in its detectors pixels. But, as reported by James Ingalls (Spitzer Science Center, Caltech), observers are circumventing this issue by using what they call the staring mode (avoiding large pointing jumps) and an algorithm to pick sweet spot pixels. Moreover, the results from the IRAC Data Challenge are helping to better understand its behavior. Giuseppe Morello (University College London), on the other hand, explained how his research group gets rid of instrumental effects from IRAC using machine learning. This method removes systematics from exoplanet transit data no matter if the noise source is from an instrument or

  10. Magnetic bead-based enzyme-chromogenic substrate system for ultrasensitive colorimetric immunoassay accompanying cascade reaction for enzymatic formation of squaric acid-iron(III) chelate.

    PubMed

    Lai, Wenqiang; Tang, Dianping; Zhuang, Junyang; Chen, Guonan; Yang, Huanghao

    2014-05-20

    This work reports on a simple and feasible colorimetric immunoassay with signal amplification for sensitive determination of prostate-specific antigen (PSA, used as a model) at an ultralow concentration by using a new enzyme-chromogenic substrate system. We discovered that glucose oxidase (GOx), the enzyme broadly used in enzyme-linked immunosorbent assay (ELISA), has the ability to stimulate in situ formation of squaric acid (SQA)-iron(III) chelate. GOx-catalyzed oxidization of glucose leads to the formation of gluconic acid and hydrogen peroxide (H2O2). The latter can catalytically oxidize iron(II) to iron(III), which can rapidly (<1 min) coordinate with the SQA. Formation of the iron-squarate complex causes the color of the solution to change from bluish purple to bluish red accompanying the increasing absorbance with the increment of iron(III) concentration. On the basis of the SQA-iron(III) system, a new immunoassay protocol with GOx-labeled anti-PSA detection antibody can be designed for the detection of target PSA on capture antibody-functionalized magnetic immunosensing probe, monitored by recording the color or absorbance (λ = 468 nm) of the generated SQA-iron(III) chelate. The absorbance intensity shows to be dependent on the concentration of target PSA. A linear dependence between the absorbance and target PSA concentration is obtained under optimal conditions in the range from 1.0 pg mL(-1) to 30 ng mL(-1) with a detection limit (LOD) of 0.5 pg mL(-1) (0.5 ppt) estimated at the 3Sblank level. The sensitivity displays to be 3-5 orders of magnitude better than those of most commercialized human PSA ELISA kits. In addition, the developed colorimetric immunoassay was validated by assaying 12 human serum samples, receiving in good accordance with those obtained by the commercialized PSA ELISA kit. Importantly, the SQA-based immunosensing system can be further extended for the detection of other low-abundance proteins or biomarkers by controlling the target

  11. Superconducting cascade electron refrigerator

    SciTech Connect

    Camarasa-Gómez, M.; Giazotto, F.; Di Marco, A.; Hekking, F. W. J.; Winkelmann, C. B.; Courtois, H.

    2014-05-12

    The design and operation of an electronic cooler based on a combination of superconducting tunnel junctions is described. The cascade extraction of hot-quasiparticles, which stems from the energy gaps of two different superconductors, allows for a normal metal to be cooled down to about 100 mK starting from a bath temperature of 0.5 K. We discuss the practical implementation, potential performance, and limitations of such a device.

  12. Information cascade on networks

    NASA Astrophysics Data System (ADS)

    Hisakado, Masato; Mori, Shintaro

    2016-05-01

    In this paper, we discuss a voting model by considering three different kinds of networks: a random graph, the Barabási-Albert (BA) model, and a fitness model. A voting model represents the way in which public perceptions are conveyed to voters. Our voting model is constructed by using two types of voters-herders and independents-and two candidates. Independents conduct voting based on their fundamental values; on the other hand, herders base their voting on the number of previous votes. Hence, herders vote for the majority candidates and obtain information relating to previous votes from their networks. We discuss the difference between the phases on which the networks depend. Two kinds of phase transitions, an information cascade transition and a super-normal transition, were identified. The first of these is a transition between a state in which most voters make the correct choices and a state in which most of them are wrong. The second is a transition of convergence speed. The information cascade transition prevails when herder effects are stronger than the super-normal transition. In the BA and fitness models, the critical point of the information cascade transition is the same as that of the random network model. However, the critical point of the super-normal transition disappears when these two models are used. In conclusion, the influence of networks is shown to only affect the convergence speed and not the information cascade transition. We are therefore able to conclude that the influence of hubs on voters' perceptions is limited.

  13. Superconducting cascade electron refrigerator

    NASA Astrophysics Data System (ADS)

    Camarasa-Gómez, M.; Di Marco, A.; Hekking, F. W. J.; Winkelmann, C. B.; Courtois, H.; Giazotto, F.

    2014-05-01

    The design and operation of an electronic cooler based on a combination of superconducting tunnel junctions is described. The cascade extraction of hot-quasiparticles, which stems from the energy gaps of two different superconductors, allows for a normal metal to be cooled down to about 100 mK starting from a bath temperature of 0.5 K. We discuss the practical implementation, potential performance, and limitations of such a device.

  14. The role of the arachidonic acid cascade in the species-specific X-ray-induced inflammation of the rabbit eye

    SciTech Connect

    Bito, L.Z.; Klein, E.M.

    1982-05-01

    To identify the mediator(s) of the apparently species-specific X-ray-induced inflammation of the rabbit eye, inhibitors of the synthesis and/or release of known or putative mediators of ocular inflammation were administered prior to irradiation. The X-ray-induced ocular inflammation, particularly the rise in intraocular pressure, was found to be inhibited by intravenous pretreatment of rabbits with flurbiprofen, indomethacin, or imidazole (1, 10, and 100 mg/kg i.v., respectively), or by combined intravitreal and topical administration of flurbiprofen. Systemic, intravitreal, and/or topical pretreatment with prednisolone or disodium cromoglycate or the retrobulbar injection of ethyl alcohol or capsaicin failed to block the inflammatory response, whereas vitamin E apparently exerted some protective effect. These findings show that the X-ray-induced inflammation of the rabbit eye is mediated, at least in part, by prostaglandins (PGs) and/or related autacoids. In addition, these results suggest that the unique sensitivity of the rabbit eye to X-ray-induced inflammation is due either to the presence in this species of a unique or uniquely effective triggering mechanism for the release of PG precursors or to the greater sensitivity of this species to the ocular inflammatory effects of PGs. Thus the rabbit eye may provide a unique model for studying some aspects of arachidonic acid release or ocular PG effects, but extreme caution must be exercised in generalizing such findings to other species.

  15. AA9 and AA10: from enigmatic to essential enzymes.

    PubMed

    Corrêa, Thamy Lívia Ribeiro; dos Santos, Leandro Vieira; Pereira, Gonçalo Amarante Guimarães

    2016-01-01

    The lignocellulosic biomass, comprised mainly of cellulose, hemicellulose, and lignin, is a strong competitor for petroleum to obtain fuels and other products because of its renewable nature, low cost, and non-competitiveness with food production when obtained from agricultural waste. Due to its recalcitrance, lignocellulosic material requires an arsenal of enzymes for its deconstruction and the consequent release of fermentable sugars. In this context, enzymes currently classified as auxiliary activity 9 (AA9/formerly GH61) and 10 (AA10/formerly CBM 33) or lytic polysaccharide monooxygenases (LPMO) have emerged as cellulase boosting enzymes. AA9 and AA10 are the new paradigm for deconstruction of lignocellulosic biomass by enhancing the activity and decreasing the loading of classical enzymes to the reaction and, consequently, reducing costs of the hydrolysis step in the second-generation ethanol production chain. In view of that disclosed above, the goal of this work is to review experimental data that supports the relevance of AA9 and AA10 for the biomass deconstruction field. PMID:26476647

  16. AAS 227: Day 4

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Welcome to Day 4 of the winter American Astronomical Society (AAS) meeting in Kissimmee! Several of us are attending the conference this year, and we will report highlights from each day here on astrobites. If youd like to see more timely updates during the day, we encourage you to follow @astrobites on twitter or search the #aas227 hashtag.Helen B. Warner Prize: Origins of Structure in Planetary Systems (by Erika Nesvold)Another excellent prize lecture started off todays sessions. The Helen B. Warner Prize is awarded for achievement in observational or theoretical astrophysics by a young researcher (no more than eight years after their Ph.D.). This years Warner Prize was presented to Ruth Murray-Clay of UC Santa Barbara. For her award lecture, Murray-Clay told us all about planetary system architecture: the number, masses, and orbits of planets in a given system.Ruth Murray-Clay [photo from http://web.physics.ucsb.edu/ ~murray/biocv.html]The underlying question motivating this type of research is: How rare is the Solar System? In other words, how likely is it that a given planetary system will have rocky planets close to their star, gas giants farther out, and ice giants at the outer reaches of the system? Answering this question will help us solve the physics problem of how and where planets form, and will also help us on our search for other planets like Earth.The data on exoplanet population from transit and radial velocity observations and from direct imaging tell us that our Solar System is not common (many systems we observe have much more eccentric gas giants), but that doesnt

  17. AAS 228: Day 4

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note: Lastweek we were at the 228th AAS Meeting in San Diego, CA. Here is a final post aboutselectedevents on the last day of the meeting, written by authors fromastrobites.com, a grad-student collaborative project with which we recently announced a new partnership! Starting in July,keep an eye out for astrobites postsat AAS Nova in between Highlights(i.e., on Tuesdays and Thursdays).Were excited to be working together to bring you more recent astronomy research from AAS journals!Extrasolar Planets: Detection (by Leonardo dos Santos)Thursdays first session on exoplanets was about detecting these distant worlds, and the opening talk was given by Robert Siverd (Las Cumbres Observatory). He describes the NRES, a network of spectrographs that will look for exoplanets using the radial velocity method. One of the coolest aspects of this instrument is that it will feature an on the fly scheduling system that will perform observations as efficiently as possible. The spectrograph is still being tested, but a unit will be deployed at CTIO later this year.@lcogt contracted by @NASA_TESS for follow up of their candidates. #aas228 Jessie Christiansen (@aussiastronomer) June 16, 2016Measuring the depths of transits and eclipses in Spitzer has been problematic in the past, since the Spitzer instrument IRAC (InfraRed Array Camera) has a non-uniform response in its detectors pixels. But, as reported by James Ingalls (Spitzer Science Center, Caltech), observers are circumventing this issue by using what they call the staring mode (avoiding large pointing jumps) and an algorithm to pick sweet spot pixels. Moreover, the results from the IRAC Data Challenge are helping to better understand its behavior. Giuseppe Morello (University College London), on the other hand, explained how his research group gets rid of instrumental effects from IRAC using machine learning. This method removes systematics from exoplanet transit data no matter if the noise source is from an instrument or

  18. Glycyrrhetinic acid induces cytoprotective autophagy via the inositol-requiring enzyme 1α-c-Jun N-terminal kinase cascade in non-small cell lung cancer cells

    PubMed Central

    Tang, Zheng-Hai; Zhang, Le-Le; Li, Ting; Lu, Jia-Hong; Ma, Dik-Lung; Leung, Chung-Hang; Chen, Xiu-Ping; Jiang, Hu-Lin; Wang, Yi-Tao; Lu, Jin-Jian

    2015-01-01

    Glycerrhetinic acid (GA), one of the main bioactive constituents of Glycyrrhiza uralensis Fisch, exerts anti-cancer effects on various cancer cells. We confirmed that GA inhibited cell proliferation and induced apoptosis in non-small cell lung cancer A549 and NCI-H1299 cells. GA also induced expression of autophagy marker phosphatidylethanolamine-modified microtubule-associated protein light-chain 3 (LC3-II) and punta formation of green fluorescent protein microtubule-associated protein light-chain 3. We further proved that expression of GA-increased autophagy marker was attributed to activation instead of suppression of autophagic flux. The c-jun N-terminal kinase (JNK) pathway was activated after incubation with GA. Pretreatment with the JNK inhibitor SP600125 or silencing of the JNK pathway by siRNA of JNK or c-jun decreased GA-induced autophagy. The endoplasmic reticulum (ER) stress responses were also apparently stimulated by GA by triggering the inositol-requiring enzyme 1α (IRE1α) pathway. The GA-induced JNK pathway activation and autophagy were decreased by IRE1α knockdown, and inhibition of autophagy or the JNK cascade increased GA-stimulated IRE1α expression. In addition, GA-induced cell proliferative inhibition and apoptosis were increased by inhibition of autophagy or the JNK pathway. Our study was the first to demonstrate that GA induces cytoprotective autophagy in non-small cell lung cancer cells by activating the IRE1α-JNK/c-jun pathway. The combined treatment of autophagy inhibitors markedly enhances the anti-neoplasmic activity of GA. Such combination shows potential as a strategy for GA or GA-contained prescriptions in cancer therapy. PMID:26549806

  19. AAS 227: Day 4

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Editors Note:This week were at the 227th AAS Meeting in Kissimmee, FL. Along with several fellow authors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting at the end of each day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Welcome to Day 4 of the winter American Astronomical Society (AAS) meeting in Kissimmee! Several of us are attending the conference this year, and we will report highlights from each day here on astrobites. If youd like to see more timely updates during the day, we encourage you to follow @astrobites on twitter or search the #aas227 hashtag.Helen B. Warner Prize: Origins of Structure in Planetary Systems (by Erika Nesvold)Another excellent prize lecture started off todays sessions. The Helen B. Warner Prize is awarded for achievement in observational or theoretical astrophysics by a young researcher (no more than eight years after their Ph.D.). This years Warner Prize was presented to Ruth Murray-Clay of UC Santa Barbara. For her award lecture, Murray-Clay told us all about planetary system architecture: the number, masses, and orbits of planets in a given system.Ruth Murray-Clay [photo from http://web.physics.ucsb.edu/ ~murray/biocv.html]The underlying question motivating this type of research is: How rare is the Solar System? In other words, how likely is it that a given planetary system will have rocky planets close to their star, gas giants farther out, and ice giants at the outer reaches of the system? Answering this question will help us solve the physics problem of how and where planets form, and will also help us on our search for other planets like Earth.The data on exoplanet population from transit and radial velocity observations and from direct imaging tell us that our Solar System is not common (many systems we observe have much more eccentric gas giants), but that doesnt

  20. The Ufm1 Cascade

    PubMed Central

    Daniel, Jens; Liebau, Eva

    2014-01-01

    The ubiquitin-fold modifier 1 (Ufm1) is a posttranslational modifier that belongs to the ubiquitin-like protein (UBL) family. Ufm1 is present in nearly all eukaryotic organisms, with the exception of fungi. It resembles ubiquitin in its ability to be ligated to other proteins, as well as in the mechanism of ligation. While the Ufm1 cascade has been implicated in endoplasmic reticulum functions and cell cycle control, its biological role still remains poorly understood. In this short review, we summarize the current state of Ufm1 research and its potential role in human diseases, like diabetes, ischemic heart disease and cancer. PMID:24921187

  1. Cascade Error Projection Learning Algorithm

    NASA Technical Reports Server (NTRS)

    Duong, T. A.; Stubberud, A. R.; Daud, T.

    1995-01-01

    A detailed mathematical analysis is presented for a new learning algorithm termed cascade error projection (CEP) and a general learning frame work. This frame work can be used to obtain the cascade correlation learning algorithm by choosing a particular set of parameters.

  2. Cascade physics at CLAS12

    SciTech Connect

    Guo, Lei

    2009-01-01

    Cascade spectroscopy offers rich discovering opportunities that are essential to the current JLAB spectroscopy program at both CLAS, CLAS12 and GLUEX. Recent CLAS results have demonstrated the feasibility to study cascade resonances through photoproduction. The cross sections for the ground state cascade is observed to increase as a function of energy in the range of 2.8-5GeV. With the maximum achievable energy at CLAS12 with the current tagger being 6.3~GeV, cascade resonances up to 2.4~GeV are expected to be produced with reasonable rates. The possible addition of a RICH detector would certainly benefit physics programs requiring the detection of kaons, especially cascade physics.

  3. Cascade Distillation System Development

    NASA Technical Reports Server (NTRS)

    Callahan, Michael R.; Sargushingh, Miriam; Shull, Sarah

    2014-01-01

    NASA's Advanced Exploration Systems (AES) Life Support System (LSS) Project is chartered with de-veloping advanced life support systems that will ena-ble NASA human exploration beyond low Earth orbit (LEO). The goal of AES is to increase the affordabil-ity of long-duration life support missions, and to re-duce the risk associated with integrating and infusing new enabling technologies required to ensure mission success. Because of the robust nature of distillation systems, the AES LSS Project is pursuing develop-ment of the Cascade Distillation Subsystem (CDS) as part of its technology portfolio. Currently, the system is being developed into a flight forward Generation 2.0 design.

  4. Cascaded radiation pressure acceleration

    SciTech Connect

    Pei, Zhikun; Shen, Baifei E-mail: zhxm@siom.ac.cn; Zhang, Xiaomei E-mail: zhxm@siom.ac.cn; Wang, Wenpeng; Zhang, Lingang; Yi, Longqing; Shi, Yin; Xu, Zhizhan

    2015-07-15

    A cascaded radiation-pressure acceleration scheme is proposed. When an energetic proton beam is injected into an electrostatic field moving at light speed in a foil accelerated by light pressure, protons can be re-accelerated to much higher energy. An initial 3-GeV proton beam can be re-accelerated to 7 GeV while its energy spread is narrowed significantly, indicating a 4-GeV energy gain for one acceleration stage, as shown in one-dimensional simulations and analytical results. The validity of the method is further confirmed by two-dimensional simulations. This scheme provides a way to scale proton energy at the GeV level linearly with laser energy and is promising to obtain proton bunches at tens of gigaelectron-volts.

  5. Interband cascade lasers

    NASA Astrophysics Data System (ADS)

    Vurgaftman, I.; Weih, R.; Kamp, M.; Meyer, J. R.; Canedy, C. L.; Kim, C. S.; Kim, M.; Bewley, W. W.; Merritt, C. D.; Abell, J.; Höfling, S.

    2015-04-01

    We review the current status of interband cascade lasers (ICLs) emitting in the midwave infrared (IR). The ICL may be considered the hybrid of a conventional diode laser that generates photons via electron-hole recombination, and an intersubband-based quantum cascade laser (QCL) that stacks multiple stages for enhanced current efficiency. Following a brief historical overview, we discuss theoretical aspects of the active region and core designs, growth by molecular beam epitaxy, and the processing of broad-area, narrow-ridge, and distributed feedback (DFB) devices. We then review the experimental performance of pulsed broad area ICLs, as well as the continuous-wave (cw) characteristics of narrow ridges having good beam quality and DFBs producing output in a single spectral mode. Because the threshold drive powers are far lower than those of QCLs throughout the λ = 3-6 µm spectral band, ICLs are increasingly viewed as the laser of choice for mid-IR laser spectroscopy applications that do not require high output power but need to be hand-portable and/or battery operated. Demonstrated ICL performance characteristics to date include threshold current densities as low as 106 A cm-2 at room temperature (RT), cw threshold drive powers as low as 29 mW at RT, maximum cw operating temperatures as high as 118 °C, maximum cw output powers exceeding 400 mW at RT, maximum cw wallplug efficiencies as high as 18% at RT, maximum cw single-mode output powers as high as 55 mW at RT, and single-mode output at λ = 5.2 µm with a cw drive power of only 138 mW at RT.

  6. Systemic AA amyloidosis in the common marmoset.

    PubMed

    Ludlage, E; Murphy, C L; Davern, S M; Solomon, A; Weiss, D T; Glenn-Smith, D; Dworkin, S; Mansfield, K G

    2005-03-01

    The common marmoset (Callithrix jacchus) is a small New World primate native to Brazil that has been used extensively in biomedical research. A retrospective analysis of archived hematoxylin and eosin-stained tissue sections and clinical records was conducted at the New England Primate Research Center on 86 marmosets more than 1 year of age that were euthanized during the past decade because of morbidity and failure to thrive. Approximately 17% (15 of 86) were found to have amyloid deposits in one or more organs, including the liver, adrenal glands, kidneys, and intestine. This material was shown by amino acid sequence analysis to be composed of serum amyloid A (SAA)-related protein. This type of amyloidosis, designated AA or "secondary," is associated typically with an inflammatory process that induces elevated levels of the SAA amyloidogenic precursor molecule. Notably, there were no significant pathologic differences or other distinguishing features in animals with amyloid versus those without; furthermore, on the basis of the limited number of serum specimens available for analysis, the SAA concentrations in the two groups were comparable, thus suggesting the possible inheritable nature of the disorder. In this respect, the common marmoset provides a unique experimental model for study of the pathogenesis and treatment of AA and other forms of systemic amyloidosis. PMID:15753464

  7. Plant MAPK cascades: Just rapid signaling modules?

    PubMed Central

    Boudsocq, Marie; Danquah, Agyemang; de Zélicourt, Axel; Hirt, Heribert; Colcombet, Jean

    2015-01-01

    Abscisic acid (ABA) is a major phytohormone mediating important stress-related processes. We recently unveiled an ABA-activated MAPK signaling module constituted of MAP3K17/18-MKK3-MPK1/2/7/14. Unlike classical rapid MAPK activation, we showed that the activation of the new MAPK module is delayed and relies on the MAP3K protein synthesis. In this addendum, we discuss the role of this original and unexpected activation mechanism of MAPK cascades which suggests that MAPKs can regulate both early and long-term plant stress responses. PMID:26313321

  8. Cascade Mtns. Oregon

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The ground near one of the long-dormant Three Sisters volcanoes in the Cascade Mountains of west-central Oregon has risen approximately 10centimeters in a 10-by-20-km parcel since 1996, meaning that magma or underground lava is slowly flowing into the area, according to a research team from the U.S. Geological Survey. The Three Sisters area -- which contains five volcanoes -- is only about 170 miles from Mount St. Helens, which erupted in 1980. Both are part of the Cascades Range, a line of 27volcanoes stretching from British Columbia in Canada to northern California. This perspective view was created by draping a simulated natural color ASTER image over digital topography from the U.S. Geological Survey National Elevation Dataset.

    This image was acquired on May 28, 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, along-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical

  9. Cascading Effects Following Intervention

    PubMed Central

    Patterson, Gerald R.; Forgatch, Marion S.; DeGarmo, David S.

    2010-01-01

    Four different sources for cascade effects were examined using 9-year process and outcome data from a randomized controlled trial (RCT) of a preventive intervention using Parent Management Training – Oregon Model (PMTO™). The social interaction learning (SIL) model of child antisocial behavior serves as one basis for predicting change. A second source addresses the issue of comorbid relationships among clinical diagnoses. The third source, collateral changes, describes events in which changes in one family member correlate with changes in another. The fourth component is based on the long-term effects of reducing coercion and increasing positive interpersonal processes within the family. New findings from the 9-year follow-up show that mothers experienced benefits as measured by standard of living (i.e., income, occupation, education, and financial stress) and frequency of police arrests. It is assumed that PMTO reduces the level of coercion, which sets the stage for a massive increase in positive social interaction. In effect, PMTO alters the family environment and thereby opens doors to healthy new social environments. PMID:20883592

  10. Terahertz quantum cascade VECSEL

    NASA Astrophysics Data System (ADS)

    Xu, Luyao; Curwen, Christopher A.; Hon, Philip W. C.; Itoh, Tatsuo; Williams, Benjamin S.

    2016-03-01

    Vertical-external-cavity surface-emitting lasers (VECSELs) have been successfully used in the visible and near-infrared to achieve high output power with excellent Gaussian beam quality. However, the concept of VECSEL has been impossible to implement for quantum-cascade (QC) lasers due to the "intersubband selection rule". We have recently demonstrated the first VECSEL in the terahertz range. The enabling component for the QC-VECSEL is an amplifying metasurface reflector composed of a sparse array of metallic sub-cavities, which allows the normally incident radiation to interact with the electrically pumped QC gain medium. In this work, we presented multiple design variations based on the first demonstrated THz QC-VECSEL, regarding the lasing frequencies, the output coupler and the intra-cavity aperture. Our work on THz QC-VECSEL initiates a new approach towards achieving scalable output power in combination with a diffraction-limited beam pattern for THz QC-lasers. The design variations presented in this work further demonstrate the practicality and potential of VECSEL approach to make ideal terahertz QC-laser sources.

  11. Design of choking cascade turns

    NASA Astrophysics Data System (ADS)

    Baird, J.

    1982-12-01

    Five different shock-positioning cascades, for short-radius turns in ramjet inlet diffusers, were designed and tested on the AFIT water table. These flow controllers were to perform the same function as the conventional arrangement of an aerodynamic grid and a long-radius turn. The tests were to determine the suitability of the water table for such experimentation, in addition to determining the flow-control capabilities and pressure recovery of the cascades. All five designs accomplished the flow-control function as designed, and two designs exhibited the same or better pressure recovery than the aerodynamic grid. The water table proved to be an excellent means of testing these cascades, primarily due to the ease of flow visualization in the tests done. The shock-positioning cascade, short-radius turn concept shows promise and should be tested further in gas-dynamic apparatus.

  12. Cascade redox flow battery systems

    DOEpatents

    Horne, Craig R.; Kinoshita, Kim; Hickey, Darren B.; Sha, Jay E.; Bose, Deepak

    2014-07-22

    A reduction/oxidation ("redox") flow battery system includes a series of electrochemical cells arranged in a cascade, whereby liquid electrolyte reacts in a first electrochemical cell (or group of cells) before being directed into a second cell (or group of cells) where it reacts before being directed to subsequent cells. The cascade includes 2 to n stages, each stage having one or more electrochemical cells. During a charge reaction, electrolyte entering a first stage will have a lower state-of-charge than electrolyte entering the nth stage. In some embodiments, cell components and/or characteristics may be configured based on a state-of-charge of electrolytes expected at each cascade stage. Such engineered cascades provide redox flow battery systems with higher energy efficiency over a broader range of current density than prior art arrangements.

  13. Stochastic background of atmospheric cascades

    SciTech Connect

    Wilk, G. ); Wlodarczyk, Z. )

    1993-06-15

    Fluctuations in the atmospheric cascades developing during the propagation of very high energy cosmic rays through the atmosphere are investigated using stochastic branching model of pure birth process with immigration. In particular, we show that the multiplicity distributions of secondaries emerging from gamma families are much narrower than those resulting from hadronic families. We argue that the strong intermittent like behaviour found recently in atmospheric families results from the fluctuations in the cascades themselves and are insensitive to the details of elementary interactions.

  14. Computation of inverse magnetic cascades

    NASA Technical Reports Server (NTRS)

    Montgomery, D.

    1981-01-01

    Inverse cascades of magnetic quantities for turbulent incompressible magnetohydrodynamics are reviewed, for two and three dimensions. The theory is extended to the Strauss equations, a description intermediate between two and three dimensions appropriate to Tokamak magnetofluids. Consideration of the absolute equilibrium Gibbs ensemble for the system leads to a prediction of an inverse cascade of magnetic helicity, which may manifest itself as a major disruption. An agenda for computational investigation of this conjecture is proposed.

  15. Stochastic background of atmospheric cascades

    NASA Astrophysics Data System (ADS)

    Wilk, G.; WŁOdarczyk, Z.

    1993-06-01

    Fluctuations in the atmospheric cascades developing during the propagation of very high energy cosmic rays through the atmosphere are investigated using stochastic branching model of pure birth process with immigration. In particular, we show that the multiplicity distributions of secondaries emerging from gamma families are much narrower than those resulting from hadronic families. We argue that the strong intermittent like behaviour found recently in atmospheric families results from the fluctuations in the cascades themselves and are insensitive to the details of elementary interactions.

  16. The cascade high productivity language

    NASA Technical Reports Server (NTRS)

    Callahan, David; Chamberlain, Branford L.; Zima, Hans P.

    2004-01-01

    This paper describes the design of Chapel, the Cascade High Productivity Language, which is being developed in the DARPA-funded HPCS project Cascade led by Cray Inc. Chapel pushes the state-of-the-art in languages for HEC system programming by focusing on productivity, in particular by combining the goal of highest possible object code performance with that of programmability offered by a high-level user interface.

  17. Computation of inverse magnetic cascades

    SciTech Connect

    Montgomery, D.

    1981-10-01

    Inverse cascades of magnetic quantities for turbulent incompressible magnetohydrodynamics are reviewed, for two and three dimensions. The theory is extended to the Strauss equations, a description intermediate between two and three dimensions appropriate to tokamak magnetofluids. Consideration of the absolute equilibrium Gibbs ensemble for the system leads to a prediction of an inverse cascade of magnetic helicity, which may manifest itself as a major disruption. An agenda for computational investigation of this conjecture is proposed.

  18. Cascading gravity is ghost free

    SciTech Connect

    Rham, Claudia de; Khoury, Justin; Tolley, Andrew J.

    2010-06-15

    We perform a full perturbative stability analysis of the 6D cascading gravity model in the presence of 3-brane tension. We demonstrate that for sufficiently large tension on the (flat) 3-brane, there are no ghosts at the perturbative level, consistent with results that had previously only been obtained in a specific 5D decoupling limit. These results establish the cascading gravity framework as a consistent infrared modification of gravity.

  19. Interband Cascade Photovoltaic Cells

    SciTech Connect

    Yang, Rui Q.; Santos, Michael B.; Johnson, Matthew B.

    2014-09-24

    In this project, we are performing basic and applied research to systematically investigate our newly proposed interband cascade (IC) photovoltaic (PV) cells [1]. These cells follow from the great success of infrared IC lasers [2-3] that pioneered the use of quantum-engineered IC structures. This quantum-engineered approach will enable PV cells to efficiently convert infrared radiation from the sun or other heat source, to electricity. Such cells will have important applications for more efficient use of solar energy, waste-heat recovery, and power beaming in combination with mid-infrared lasers. The objectives of our investigations are to: achieve extensive understanding of the fundamental aspects of the proposed PV structures, develop the necessary knowledge for making such IC PV cells, and demonstrate prototype working PV cells. This research will focus on IC PV structures and their segments for utilizing infrared radiation with wavelengths from 2 to 5 μm, a range well suited for emission by heat sources (1,000-2,000 K) that are widely available from combustion systems. The long-term goal of this project is to push PV technology to longer wavelengths, allowing for relatively low-temperature thermal sources. Our investigations address material quality, electrical and optical properties, and their interplay for the different regions of an IC PV structure. The tasks involve: design, modeling and optimization of IC PV structures, molecular beam epitaxial growth of PV structures and relevant segments, material characterization, prototype device fabrication and testing. At the end of this program, we expect to generate new cutting-edge knowledge in the design and understanding of quantum-engineered semiconductor structures, and demonstrate the concepts for IC PV devices with high conversion efficiencies.

  20. Arachidonic acid mediates muscarinic inhibition and enhancement of N-type Ca2+ current in sympathetic neurons

    PubMed Central

    Liu, Liwang; Rittenhouse, Ann R.

    2003-01-01

    N-type Ca2+ channels participate in acute activity-dependent processes such as regulation of Ca2+-activated K+ channels and in more prolonged events such as gene transcription and long-term depression. A slow postsynaptic M1 muscarinic receptor-mediated modulation of N-type current in superior cervical ganglion neurons may be important in regulating these processes. This slow pathway inhibits N-type current by using a diffusible second messenger that has remained unidentified for more than a decade. Using whole-cell patch–clamp techniques, which isolate the slow pathway, we found that the muscarinic agonist oxotremorine methiodide not only inhibits currents at positive potentials but enhances N-type current at negative potentials. Enhancement was also observed in cell-attached patches. These findings provide evidence for N-type Ca2+-current enhancement by a classical neurotransmitter. Moreover, enhancement and inhibition of current by oxotremorine methiodide mimics modulation observed with direct application of a low concentration of arachidonic acid (AA). Although no transmitter has been reported to use AA as a second messenger to modulate any Ca2+ current in either neuronal or nonneuronal cells, we nevertheless tested whether a fatty acid signaling cascade was involved. Blocking phospholipase C, phospholipase A2, or AA but not AA metabolism minimized muscarinic modulation of N-type current, supporting the participation of these molecules in the slow pathway. A role for the G protein Gq was also confirmed by blocking muscarinic modulation of Ca2+ currents with anti-Gqα antibody. Our finding that AA participates in the slow pathway strongly suggests that it may be the previously unknown diffusible second messenger. PMID:12496347

  1. Laboratory Astrophysics Division of The AAS (LAD)

    NASA Astrophysics Data System (ADS)

    Salama, Farid; Drake, R. P.; Federman, S. R.; Haxton, W. C.; Savin, D. W.

    2012-10-01

    The purpose of the Laboratory Astrophysics Division (LAD) is to advance our understanding of the Universe through the promotion of fundamental theoretical and experimental research into the underlying processes that drive the Cosmos. LAD represents all areas of astrophysics and planetary sciences. The first new AAS Division in more than 30 years, the LAD traces its history back to the recommendation from the scientific community via the White Paper from the 2006 NASA-sponsored Laboratory Astrophysics Workshop. This recommendation was endorsed by the Astronomy and Astrophysics Advisory Committee (AAAC), which advises the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the U.S. Department of Energy (DOE) on selected issues within the fields of astronomy and astrophysics that are of mutual interest and concern to the agencies. In January 2007, at the 209th AAS meeting, the AAS Council set up a Steering Committee to formulate Bylaws for a Working Group on Laboratory Astrophysics (WGLA). The AAS Council formally established the WGLA with a five-year mandate in May 2007, at the 210th AAS meeting. From 2008 through 2012, the WGLA annually sponsored Meetings in-a-Meeting at the AAS Summer Meetings. In May 2011, at the 218th AAS meeting, the AAS Council voted to convert the WGLA, at the end of its mandate, into a Division of the AAS and requested draft Bylaws from the Steering Committee. In January 2012, at the 219th AAS Meeting, the AAS Council formally approved the Bylaws and the creation of the LAD. The inaugural gathering and the first business meeting of the LAD were held at the 220th AAS meeting in Anchorage in June 2012. You can learn more about LAD by visiting its website at http://lad.aas.org/ and by subscribing to its mailing list.

  2. Laboratory Astrophysics Division of the AAS (LAD)

    NASA Technical Reports Server (NTRS)

    Salama, Farid; Drake, R. P.; Federman, S. R.; Haxton, W. C.; Savin, D. W.

    2012-01-01

    The purpose of the Laboratory Astrophysics Division (LAD) is to advance our understanding of the Universe through the promotion of fundamental theoretical and experimental research into the underlying processes that drive the Cosmos. LAD represents all areas of astrophysics and planetary sciences. The first new AAS Division in more than 30 years, the LAD traces its history back to the recommendation from the scientific community via the White Paper from the 2006 NASA-sponsored Laboratory Astrophysics Workshop. This recommendation was endorsed by the Astronomy and Astrophysics Advisory Committee (AAAC), which advises the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the U.S. Department of Energy (DOE) on selected issues within the fields of astronomy and astrophysics that are of mutual interest and concern to the agencies. In January 2007, at the 209th AAS meeting, the AAS Council set up a Steering Committee to formulate Bylaws for a Working Group on Laboratory Astrophysics (WGLA). The AAS Council formally established the WGLA with a five-year mandate in May 2007, at the 210th AAS meeting. From 2008 through 2012, the WGLA annually sponsored Meetings in-a-Meeting at the AAS Summer Meetings. In May 2011, at the 218th AAS meeting, the AAS Council voted to convert the WGLA, at the end of its mandate, into a Division of the AAS and requested draft Bylaws from the Steering Committee. In January 2012, at the 219th AAS Meeting, the AAS Council formally approved the Bylaws and the creation of the LAD. The inaugural gathering and the first business meeting of the LAD were held at the 220th AAS meeting in Anchorage in June 2012. You can learn more about LAD by visiting its website at http://lad.aas.org/ and by subscribing to its mailing list.

  3. Dependence of intestinal amino acid uptake on dietary protein or amino acid levels

    SciTech Connect

    Karasov, W.H.; Solberg, D.H.; Diamond, J.M.

    1987-05-01

    To understand how intestinal amino acid (AA) transport is regulated by dietary substrate levels, the authors measured uptake of seven radioactively-labelled AAs and glucose across the jejunal brush-border membrane of mice kept on one of three isocaloric rations differing in nitrogen content. In the high-protein ration, uptake increased by 77-81% for the nonessential, less toxic AAs, proline, and aspartate but only by 32-61% for the more toxic essential AAs tested. In the nitrogen-deficient ration, uptake decreased for the nonessential aspartate and proline but stayed constant or increased for essential AAs and for the nonessential alanine. These patterns imply independent regulation of the intestine's various AA transporters. With decreasing dietary AA (or protein), the imino acid and acidic AA private transporters are repressed, while activities of the basic AA transporter and the neutral AA public transporter decrease to an asymptote or else go through a minimum. These regulatory patterns can be understood as a compromise among conflicting constraints imposed by protein's multiple roles as a source of calories, nitrogen, and essential AAs and by the toxicity of essential AAs at high concentrations.

  4. Cross-talk between TLR4 and PPARγ pathways in the arachidonic acid-induced inflammatory response in pancreatic acini.

    PubMed

    Mateu, A; Ramudo, L; Manso, M A; De Dios, I

    2015-12-01

    Arachidonic acid (AA) is generally associated with inflammation in different settings. We assess the molecular mechanisms involved in the inflammatory response exerted by AA on pancreatic acini as an approach to acute pancreatitis (AP). Celecoxib (COX-2 inhibitor), TAK-242 (TLR4 inhibitor) and 15d-PGJ2 (PPARγ agonist) were used to ascertain the signaling pathways. In addition, we examine the effects of TAK-242 and 15d-PGJ2 on AP induced in rats by bile-pancreatic duct obstruction (BPDO). To carry out in vitro studies, acini were isolated from pancreas of control rats. Generation of PGE2 and TXB2, activation of pro-inflammatory pathways (MAPKs, NF-κB, and JAK/STAT3) and overexpression of CCL2 and P-selectin was found in AA-treated acini. In addition, AA up-regulated TLR4 and down-regulated PPARγ expression. Celecoxib prevented the up-regulation of CCL2 and P-selectin but did not show any effect on the AA-mediated changes in TLR4 and PPARγ expression. TAK-242, reduced the generation of AA metabolites and repressed both the cascade of pro-inflammatory events which led to CCL2 and P-selectin overexpression as well as the AA-induced PPARγ down-regulation. Thus, TLR4 acts as upstream activating pro-inflammatory and inhibiting anti-inflammatory pathways. 15d-PGJ2 down-regulated TLR4 expression and hence prevented the synthesis of AA metabolites and the inflammatory response mediated by them. Reciprocal negative cross-talk between TLR4 and PPARγ pathways is evidenced. In vivo experiments showed that TAK-242 and 15d-PGJ2 treatments reduced the inflammatory response in BPDO-induced AP. We conclude that through TLR4-dependent mechanisms, AA up-regulated CCL2 and P-selectin in pancreatic acini, partly mediated by the generation of PGE2 and TXB2, which activated pro-inflammatory pathways, but also directly by down-regulating PPARγ expression with anti-inflammatory activity. In vitro and in vivo studies support the role of TLR4 in AP and the use of TLR4 inhibitors and

  5. Constitutive behavior of as-cast AA1050, AA3104, and AA5182

    NASA Astrophysics Data System (ADS)

    van Haaften, W. M.; Magnin, B.; Kool, W. H.; Katgerman, L.

    2002-07-01

    Recent thermomechanical modeling to calculate the stress field in industrially direct-chill (DC) cast-aluminum slabs has been successful, but lack of material data limits the accuracy of these calculations. Therefore, the constitutive behavior of three aluminum alloys (AA1050, AA3104, and AA5182) was determined in the as-cast condition using tensile tests at low strain rates and from room temperature to solidus temperature. The parameters of two constitutive equations, the extended Ludwik equation and a combination of the Sellars-Tegart equation with a hardening law, were determined. In order to study the effect of recovery, the constitutive behavior after prestraining at higher temperatures was also investigated. To evaluate the quantified constitutive equations, tensile tests were performed simulating the deformation and cooling history experienced by the material during casting. It is concluded that both constitutive equations perform well, but the combined hardening-Sellars-Tegart (HST) equation has temperature-independent parameters, which makes it easier to implement in a DC casting model. Further, the deformation history of the ingot should be taken into account for accurate stress calculations.

  6. Cascaded-cladding-pumped cascaded Raman fiber amplifier.

    PubMed

    Jiang, Huawei; Zhang, Lei; Feng, Yan

    2015-06-01

    The conversion efficiency of double-clad Raman fiber laser is limited by the cladding-to-core area ratio. To get high conversion efficiency, the inner-cladding-to-core area ratio has to be less than about 8, which limits the brightness enhancement. To overcome the problem, a cascaded-cladding-pumped cascaded Raman fiber laser with multiple-clad fiber as the Raman gain medium is proposed. A theoretical model of Raman fiber amplifier with multiple-clad fiber is developed, and numerical simulation proves that the proposed scheme can improve the conversion efficiency and brightness enhancement of cladding pumped Raman fiber laser. PMID:26072764

  7. AAS 228: Day 1 morning

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Come visit astrobites at the AAS booth we have swag!Things kicked off last night at our undergraduate reception booth. Thanks to all of you who stopped by we were delightedto hear from undergrads who already know and love the site, educators who want to use it in their classrooms, and students who had not yet been introduced to astrobites and were excited about a new resource!For the rest of the meeting we will be stationed at theAAS booth in the exhibit hall (booth #211-213), so drop by if you want to learn more (or pick up swag: weve got lots of stickers and sunglasses)!Mondaymorning was the official start of the meeting. Here are just a few of the talks and workshops astrobiters attended this morning.Opening Address(by Susanna Kohler)AAS President Meg Urry kicked off the meeting this morning at 8am with an overview of some of the great endeavors AAS is supporting. We astrobiters had personal motivation to drag ourselves out of bed that early: during this session, Urryannounced the new partnership between AAS and astrobites!Urry touched on some difficult topics in her welcome, including yesterdays tragedy in Orlando. Shereiteratedthe AASs support fortheCommittee for Sexual-Orientation and Gender Minorities in Astronomy (SGMA). She also reminded meeting attendees about the importance ofkeeping conference interactions professional, and pointed to the meetings anti-harassment policy.Partnership Announcement (by Michael Zevin)This morning, the American Astronomical Society announced the new partnership that it will have with Astrobites! We are beyond excited to embark on this new partnership with the

  8. Transmission of systemic AA amyloidosis in animals.

    PubMed

    Murakami, T; Ishiguro, N; Higuchi, K

    2014-03-01

    Amyloidoses are a group of protein-misfolding disorders that are characterized by the deposition of amyloid fibrils in organs and/or tissues. In reactive amyloid A (AA) amyloidosis, serum AA (SAA) protein forms deposits in mice, domestic and wild animals, and humans that experience chronic inflammation. AA amyloid fibrils are abnormal β-sheet-rich forms of the serum precursor SAA, with conformational changes that promote fibril formation. Extracellular deposition of amyloid fibrils causes disease in affected animals. Recent findings suggest that AA amyloidosis could be transmissible. Similar to the pathogenesis of transmissible prion diseases, amyloid fibrils induce a seeding-nucleation process that may lead to development of AA amyloidosis. We review studies of possible transmission in bovine, avian, mouse, and cheetah AA amyloidosis. PMID:24280941

  9. Rescuing Ecosystems from Extinction Cascades

    NASA Astrophysics Data System (ADS)

    Sahasrabudhe, Sagar; Motter, Adilson

    2010-03-01

    Food web perturbations stemming from climate change, overexploitation, invasive species, and natural disasters often cause an initial loss of species that results in a cascade of secondary extinctions. Using a predictive modeling framework, here we will present a systematic network-based approach to reduce the number of secondary extinctions. We will show that the extinction of one species can often be compensated by the concurrent removal of a second specific species, which is a counter-intuitive effect not previously tested in complex food webs. These compensatory perturbations frequently involve long-range interactions that are not a priori evident from local predator-prey relationships. Strikingly, in numerous cases even the early removal of a species that would eventually be extinct by the cascade is found to significantly reduce the number of cascading extinctions. Other nondestructive interventions based on partial removals and growth suppression and/or mortality increase are shown to sometimes prevent all secondary extinctions.

  10. Autoregressive cascades on random networks

    NASA Astrophysics Data System (ADS)

    Iyer, Srikanth K.; Vaze, Rahul; Narasimha, Dheeraj

    2016-04-01

    A network cascade model that captures many real-life correlated node failures in large networks via load redistribution is studied. The considered model is well suited for networks where physical quantities are transmitted, e.g., studying large scale outages in electrical power grids, gridlocks in road networks, and connectivity breakdown in communication networks, etc. For this model, a phase transition is established, i.e., existence of critical thresholds above or below which a small number of node failures lead to a global cascade of network failures or not. Theoretical bounds are obtained for the phase transition on the critical capacity parameter that determines the threshold above and below which cascade appears or disappears, respectively, that are shown to closely follow numerical simulation results.

  11. Nanowire terahertz quantum cascade lasers

    SciTech Connect

    Grange, Thomas

    2014-10-06

    Quantum cascade lasers made of nanowire axial heterostructures are proposed. The dissipative quantum dynamics of their carriers is theoretically investigated using non-equilibrium Green functions. Their transport and gain properties are calculated for varying nanowire thickness, from the classical-wire regime to the quantum-wire regime. Our calculation shows that the lateral quantum confinement provided by the nanowires allows an increase of the maximum operation temperature and a strong reduction of the current density threshold compared to conventional terahertz quantum cascade lasers.

  12. Cascaded target normal sheath acceleration

    SciTech Connect

    Wang, W. P.; Shen, B. F.; Zhang, X. M.; Wang, X. F.; Xu, J. C.; Zhao, X. Y.; Yu, Y. H.; Yi, L. Q.; Shi, Y.; Zhang, L. G.; Xu, T. J.; Xu, Z. Z.

    2013-11-15

    A cascaded target normal sheath acceleration (TNSA) scheme is proposed to simultaneously increase energy and improve energy spread of a laser-produced mono-energetic proton beam. An optimum condition that uses the maximum sheath field to accelerate the center of the proton beam is theoretically found and verified by two-dimensional particle-in-cell simulations. An initial 10 MeV proton beam is accelerated to 21 MeV with energy spread decreased from 5% to 2% under the optimum condition during the process of the cascaded TNSA. The scheme opens a way to scale proton energy lineally with laser energy.

  13. AAS 228: Day 3 afternoon

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Wikipedia Year of Science Editathon (by Meredith Rawls)Whats your first go-to source for an unfamiliar topic on the internet? If you said Wikipedia, youre not alone. For many people, Wikipedia is the primary source of information about astronomy and science. However, many Wikipedia articles about science topics are incomplete or missing, and women are underrepresented among scientists with biographies.To address this, the AAS Astronomy Education Board teamed up with the Wiki Education Foundation to host an edit-a-thon as part of the Wikipedia Year of Science. More than forty attendees spent the better part of three hours working through tutorials, creating new articles, and editing existing ones. The session was generously sponsored by the Simons Foundation.The Year of Science initiative seeks to bring Wikipedia editing skills to the classroom and help new editors find sustainable ways to contribute to Wikipedia in the long term. Anybody can create a free account and start editing!As a first-time Wikipedia contributor, I took the time to go through nearly all the tutorial exercises and familiarize myself with the process of editing a page. I decided to flesh out one section in an existing page about asteroseismology. Others created biography pages from scratch or selected various astronomical topics to write about. To me, the editing process felt like a cross between writing a blog post and a journal article, in a hack day type environment. Working through the tutorial and some examples renewed my empathy for learners who are tackling a new skill set for the first time. A full summary of our

  14. Bacillus thuringiensis subsp. israelensis Cyt1Aa synergizes Cry11Aa toxin by functioning as a membrane-bound receptor.

    PubMed

    Pérez, Claudia; Fernandez, Luisa E; Sun, Jianguang; Folch, Jorge Luis; Gill, Sarjeet S; Soberón, Mario; Bravo, Alejandra

    2005-12-20

    Bacillus thuringiensis subsp. israelensis produces crystal proteins, Cry (4Aa, 4Ba, 10Aa, and 11Aa) and Cyt (1Aa and 2Ba) proteins, toxic to mosquito vectors of human diseases. Cyt1Aa overcomes insect resistance to Cry11Aa and Cry4 toxins and synergizes the toxicity of these toxins. However, the molecular mechanism of synergism remains unsolved. Here, we provide evidence that Cyt1Aa functions as a receptor of Cry11Aa. Sequential-binding analysis of Cyt1Aa and Cry11Aa revealed that Cyt1Aa binding to Aedes aegypti brush border membrane vesicles enhanced the binding of biotinylated-Cry11Aa. The Cyt1Aa- and Cry11Aa-binding epitopes were mapped by means of the yeast two-hybrid system, peptide arrays, and heterologous competition assays with synthetic peptides. Two exposed regions in Cyt1Aa, loop beta6-alphaE and part of beta7, bind Cry11Aa. On the other side, Cry11Aa binds Cyt1Aa proteins by means of domain II-loop alpha8 and beta-4, which are also involved in midgut receptor interaction. Characterization of single-point mutations in Cry11Aa and Cyt1Aa revealed key Cry11Aa (S259 and E266) and Cyt1Aa (K198, E204 and K225) residues involved in the interaction of both proteins and in synergism. Additionally, a Cyt1Aa loop beta6-alphaE mutant (K198A) with enhanced synergism to Cry11Aa was isolated. Data provided here strongly indicates that Cyt1Aa synergizes or suppresses resistance to Cry11Aa toxin by functioning as a membrane-bound receptor. Bacillus thuringiensis subsp. israelensis is a highly effective pathogenic bacterium because it produces a toxin and also its functional receptor, promoting toxin binding to the target membrane and causing toxicity. PMID:16339907

  15. Characteristics for two kinds of cascading events

    NASA Astrophysics Data System (ADS)

    Zou, Sheng-Rong; Gu, Ai-Hua; Liu, Ai-Fen; Xu, Xiu-Lian; Wang, Jian; He, Da-Ren

    2011-04-01

    Avalanche or cascade failure is ubiquitous. We first classify the cascading phenomena into two categories: the cascading disasters which result in large-scale functional failures and the cascading events that do not lead to disasters. We elucidate that two important factors, the increasing amount of events and the acceleration of event frequency, can induce the crossover from the cascading phenomenon to the cascading disaster. Through a simplified sandpile model and a heuristic logistic map, we demonstrate that the dependence of the event number on the observation time behaves as a power-law and as an exponential for these two different cascading events, respectively. The analytic derivations are found to be consistent with several empirical observations. Our present findings contribute to the understanding of the transition between different cascading events, providing a basis for the further understanding of the transitions among more general critical events.

  16. AAS 228: Day 3 afternoon

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Wikipedia Year of Science Editathon (by Meredith Rawls)Whats your first go-to source for an unfamiliar topic on the internet? If you said Wikipedia, youre not alone. For many people, Wikipedia is the primary source of information about astronomy and science. However, many Wikipedia articles about science topics are incomplete or missing, and women are underrepresented among scientists with biographies.To address this, the AAS Astronomy Education Board teamed up with the Wiki Education Foundation to host an edit-a-thon as part of the Wikipedia Year of Science. More than forty attendees spent the better part of three hours working through tutorials, creating new articles, and editing existing ones. The session was generously sponsored by the Simons Foundation.The Year of Science initiative seeks to bring Wikipedia editing skills to the classroom and help new editors find sustainable ways to contribute to Wikipedia in the long term. Anybody can create a free account and start editing!As a first-time Wikipedia contributor, I took the time to go through nearly all the tutorial exercises and familiarize myself with the process of editing a page. I decided to flesh out one section in an existing page about asteroseismology. Others created biography pages from scratch or selected various astronomical topics to write about. To me, the editing process felt like a cross between writing a blog post and a journal article, in a hack day type environment. Working through the tutorial and some examples renewed my empathy for learners who are tackling a new skill set for the first time. A full summary of our

  17. Engineering Light: Quantum Cascade Lasers

    ScienceCinema

    Claire Gmachl

    2010-09-01

    Quantum cascade lasers are ideal for environmental sensing and medical diagnostic applications. Gmachl discusses how these lasers work, and their applications, including their use as chemical trace gas sensors. As examples of these applications, she briefly presents results from her field campaign at the Beijing Olympics, and ongoing campaigns in Texas, Maryland, and Ghana.

  18. Applications of cascade multilevel inverters.

    PubMed

    Peng, Fang-zen; Qian, Zhao-ming

    2003-01-01

    Cascade multilevel inverters have been developed for electric utility applications. A cascade M-level inverter consists of (M-1)/2 H-bridges in which each bridge's dc voltage is supported by its own dc capacitor. The new inverter can: (1) generate almost sinusoidal waveform voltage while only switching one time per fundamental cycle; (2) dispense with multi-pulse inverters' transformers used in conventional utility interfaces and static var compensators; (3) enables direct parallel or series transformer-less connection to medium- and high-voltage power systems. In short, the cascade inverter is much more efficient and suitable for utility applications than traditional multi-pulse and pulse width modulation (PWM) inverters. The authors have experimentally demonstrated the superiority of the new inverter for power supply, (hybrid) electric vehicle (EV) motor drive, reactive power (var) and harmonic compensation. This paper summarizes the features, feasibility, and control schemes of the cascade inverter for utility applications including utility interface of renewable energy, voltage regulation, var compensation, and harmonic filtering in power systems. Analytical, simulated, and experimental results demonstrated the superiority of the new inverters. PMID:14566981

  19. Dietary modulation of the inflammatory cascade.

    PubMed

    Dawson, Dolphus R; Branch-Mays, Grishondra; Gonzalez, Octavio A; Ebersole, Jeffrey L

    2014-02-01

    Dietary supplementation has traditionally consisted of adding vitamins and/or minerals to correct or prevent a nutritional deficiency. When supplementing the diet with other inflammatory mediators, such as essential fatty acids, there is an adjunctive benefit to the standard therapies used in the control of chronic inflammatory diseases such as Crohn's disease or rheumatoid arthritis. This review focuses on the strategies utilized for therapeutic modulation of the inflammatory cascade through dietary supplementation with specific biomolecules. Examples of how these biomolecules affect local and systemic immune responses to chronic inflammation are examined. In particular, an overview of the literature identifying the potential to modify the host response to chronic periodontitis is provided. PMID:24320963

  20. PANEL CODE FOR PLANAR CASCADES

    NASA Technical Reports Server (NTRS)

    Mcfarland, E. R.

    1994-01-01

    The Panel Code for Planar Cascades was developed as an aid for the designer of turbomachinery blade rows. The effective design of turbomachinery blade rows relies on the use of computer codes to model the flow on blade-to-blade surfaces. Most of the currently used codes model the flow as inviscid, irrotational, and compressible with solutions being obtained by finite difference or finite element numerical techniques. While these codes can yield very accurate solutions, they usually require an experienced user to manipulate input data and control parameters. Also, they often limit a designer in the types of blade geometries, cascade configurations, and flow conditions that can be considered. The Panel Code for Planar Cascades accelerates the design process and gives the designer more freedom in developing blade shapes by offering a simple blade-to-blade flow code. Panel, or integral equation, solution techniques have been used for several years by external aerodynamicists who have developed and refined them into a primary design tool of the aircraft industry. The Panel Code for Planar Cascades adapts these same techniques to provide a versatile, stable, and efficient calculation scheme for internal flow. The code calculates the compressible, inviscid, irrotational flow through a planar cascade of arbitrary blade shapes. Since the panel solution technique is for incompressible flow, a compressibility correction is introduced to account for compressible flow effects. The analysis is limited to flow conditions in the subsonic and shock-free transonic range. Input to the code consists of inlet flow conditions, blade geometry data, and simple control parameters. Output includes flow parameters at selected control points. This program is written in FORTRAN IV for batch execution and has been implemented on an IBM 370 series computer with a central memory requirement of approximately 590K of 8 bit bytes. This program was developed in 1982.

  1. Critical transitions in colliding cascades

    PubMed

    Gabrielov; Keilis-Borok; Zaliapin; Newman

    2000-07-01

    We consider here the interaction of direct and inverse cascades in a hierarchical nonlinear system that is continuously loaded by external forces. The load is applied to the largest element and is transferred down the hierarchy to consecutively smaller elements, thereby forming a direct cascade. The elements of the system fail (i. e., break down) under the load. The smallest elements fail first. The failures gradually expand up the hierarchy to the larger elements, thus forming an inverse cascade. Eventually the failures heal, ensuring that the system will function indefinitely. The direct and inverse cascades collide and interact. Loading triggers the failures, while failures release and redistribute the load. Notwithstanding its relative simplicity, this model reproduces the major dynamical features observed in seismicity, including the seismic cycle, intermittence of seismic regime, power-law energy distribution, clustering in space and time, long-range correlations, and a set of seismicity patterns premonitory to a strong earthquake. In this context, the hierarchical structure of the model crudely imitates a system of tectonic blocks spread by a network of faults (note that the behavior of such a network is different from that of a single fault). Loading mimics the impact of tectonic forces, and failures simulate earthquakes. The model exhibits three basic types of premonitory pattern reflecting seismic activity, clustering of earthquakes in space and time, and the range of correlation between the earthquakes. The colliding-cascade model seemingly exhibits regularities that are common in a wide class of complex hierarchical systems, not necessarily Earth specific. PMID:11088457

  2. Interface Formation During Fusion™ Casting of AA3003/AA4045 Aluminum Alloy Ingots

    NASA Astrophysics Data System (ADS)

    Di Ciano, Massimo; Caron, E. J. F. R.; Weckman, D. C.; Wells, M. A.

    2015-12-01

    Fusion™ casting is a unique Direct Chill continuous casting process whereby two different alloys can be cast simultaneously, producing a laminated ingot for rolling into clad sheet metal such as AA3003/AA4045 brazing sheet. Better understanding of the wetting and interface formation process during Fusion™ casting is required to further improve process yields and also explore use of other alloy systems for new applications. In this research, AA3003-core/AA4045-clad ingots were cast using a well-instrumented lab-scale Fusion™ casting system. As-cast Fusion™ interfaces were examined metallurgically and by mechanical testing. Computational fluid dynamic analyses of the FusionTM casts were also performed. It was shown that the liquid AA4045-clad alloy was able to successfully wet and create an oxide-free, metallurgical, and mechanically sound interface with the lightly oxidized AA3003-core shell material. Based on the results of this study, it is proposed that the bond formation process at the alloys interface during casting is a result of discrete penetration of AA4045 liquid at defects in the preexisting AA3003 oxide, dissolution of underlying AA3003 by liquid AA4045, and subsequent bridging between penetration sites. Spot exudation on the AA3003 chill cast surface due to remelting and inverse segregation may also improve the wetting and bonding process.

  3. AaCAT1 of the Yellow Fever Mosquito, Aedes aegypti

    PubMed Central

    Hansen, Immo A.; Boudko, Dmitri Y.; Shiao, Shin-Hong; Voronov, Dmitri A.; Meleshkevitch, Ella A.; Drake, Lisa L.; Aguirre, Sarah E.; Fox, Jeffrey M.; Attardo, Geoffrey M.; Raikhel, Alexander S.

    2011-01-01

    Insect yolk protein precursor gene expression is regulated by nutritional and endocrine signals. A surge of amino acids in the hemolymph of blood-fed female mosquitoes activates a nutrient signaling system in the fat bodies, which subsequently derepresses yolk protein precursor genes and makes them responsive to activation by steroid hormones. Orphan transporters of the SLC7 family were identified as essential upstream components of the nutrient signaling system in the fat body of fruit flies and the yellow fever mosquito, Aedes aegypti. However, the transport function of these proteins was unknown. We report expression and functional characterization of AaCAT1, cloned from the fat body of A. aegypti. Expression of AaCAT1 transcript and protein undergoes dynamic changes during postembryonic development of the mosquito. Transcript expression was especially high in the third and fourth larval stages; however, the AaCAT1 protein was detected only in pupa and adult stages. Functional expression and analysis of AaCAT1 in Xenopus oocytes revealed that it acts as a sodium-independent cationic amino acid transporter, with unique selectivity to l-histidine at neutral pH (K0.5l-His = 0.34 ± 0.07 mm, pH 7.2). Acidification to pH 6.2 dramatically increases AaCAT1-specific His+-induced current. RNAi-mediated silencing of AaCAT1 reduces egg yield of subsequent ovipositions. Our data show that AaCAT1 has notable differences in its transport mechanism when compared with related mammalian cationic amino acid transporters. It may execute histidine-specific transport and signaling in mosquito tissues. PMID:21262963

  4. Theophylline-7-acetic acid: lack of absorption and therapeutic effectiveness.

    PubMed Central

    Fleetham, J A; Owen, J A; May, B; Munt, P W; Nakatsu, K

    1979-01-01

    A double-blind cross-over trial was conducted to evaluate the effectiveness of oral theophylline-7-acetic acid (T7AA) in 13 asthmatic patients. Pulmonary function tests showed no difference between T7AA and placebo. No T7AA or theophylline was found in the sera of these patients or of healthy volunteers who took T7AA tablets or syrup. PMID:388714

  5. AAS 228: Day 1 morning

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Come visit astrobites at the AAS booth we have swag!Things kicked off last night at our undergraduate reception booth. Thanks to all of you who stopped by we were delightedto hear from undergrads who already know and love the site, educators who want to use it in their classrooms, and students who had not yet been introduced to astrobites and were excited about a new resource!For the rest of the meeting we will be stationed at theAAS booth in the exhibit hall (booth #211-213), so drop by if you want to learn more (or pick up swag: weve got lots of stickers and sunglasses)!Mondaymorning was the official start of the meeting. Here are just a few of the talks and workshops astrobiters attended this morning.Opening Address(by Susanna Kohler)AAS President Meg Urry kicked off the meeting this morning at 8am with an overview of some of the great endeavors AAS is supporting. We astrobiters had personal motivation to drag ourselves out of bed that early: during this session, Urryannounced the new partnership between AAS and astrobites!Urry touched on some difficult topics in her welcome, including yesterdays tragedy in Orlando. Shereiteratedthe AASs support fortheCommittee for Sexual-Orientation and Gender Minorities in Astronomy (SGMA). She also reminded meeting attendees about the importance ofkeeping conference interactions professional, and pointed to the meetings anti-harassment policy.Partnership Announcement (by Michael Zevin)This morning, the American Astronomical Society announced the new partnership that it will have with Astrobites! We are beyond excited to embark on this new partnership with the

  6. A mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK)-dependent transcriptional program controls activation of the early growth response 1 (EGR1) gene during amino acid limitation.

    PubMed

    Shan, Jixiu; Balasubramanian, Mukundh N; Donelan, William; Fu, Lingchen; Hayner, Jaclyn; Lopez, Maria-Cecilia; Baker, Henry V; Kilberg, Michael S

    2014-08-29

    Amino acid (AA) limitation in mammalian cells triggers a collection of signaling cascades jointly referred to as the AA response (AAR). In human HepG2 hepatocellular carcinoma, the early growth response 1 (EGR1) gene was induced by either AA deprivation or endoplasmic reticulum stress. AAR-dependent EGR1 activation was discovered to be independent of the well characterized GCN2-ATF4 pathway and instead dependent on MEK-ERK signaling, one of the MAPK pathways. ChIP showed that constitutively bound ELK1 at the EGR1 proximal promoter region was phosphorylated after AAR activation. Increased p-ELK1 binding was associated with increased de novo recruitment of RNA polymerase II to the EGR1 promoter. EGR1 transcription was not induced in HEK293T cells lacking endogenous MEK activity, but overexpression of exogenous constitutively active MEK in HEK293T cells resulted in increased basal and AAR-induced EGR1 expression. ChIP analysis of the human vascular endothelial growth factor A (VEGF-A) gene, a known EGR1-responsive gene, revealed moderate increases in AAR-induced EGR1 binding within the proximal promoter and highly inducible binding to a site within the first intron. Collectively, these data document a novel AA-activated MEK-ERK-ELK1 signaling mechanism. PMID:25028509

  7. A Mitogen-activated Protein Kinase/Extracellular Signal-regulated Kinase Kinase (MEK)-dependent Transcriptional Program Controls Activation of the Early Growth Response 1 (EGR1) Gene during Amino Acid Limitation*

    PubMed Central

    Shan, Jixiu; Balasubramanian, Mukundh N.; Donelan, William; Fu, Lingchen; Hayner, Jaclyn; Lopez, Maria-Cecilia; Baker, Henry V.; Kilberg, Michael S.

    2014-01-01

    Amino acid (AA) limitation in mammalian cells triggers a collection of signaling cascades jointly referred to as the AA response (AAR). In human HepG2 hepatocellular carcinoma, the early growth response 1 (EGR1) gene was induced by either AA deprivation or endoplasmic reticulum stress. AAR-dependent EGR1 activation was discovered to be independent of the well characterized GCN2-ATF4 pathway and instead dependent on MEK-ERK signaling, one of the MAPK pathways. ChIP showed that constitutively bound ELK1 at the EGR1 proximal promoter region was phosphorylated after AAR activation. Increased p-ELK1 binding was associated with increased de novo recruitment of RNA polymerase II to the EGR1 promoter. EGR1 transcription was not induced in HEK293T cells lacking endogenous MEK activity, but overexpression of exogenous constitutively active MEK in HEK293T cells resulted in increased basal and AAR-induced EGR1 expression. ChIP analysis of the human vascular endothelial growth factor A (VEGF-A) gene, a known EGR1-responsive gene, revealed moderate increases in AAR-induced EGR1 binding within the proximal promoter and highly inducible binding to a site within the first intron. Collectively, these data document a novel AA-activated MEK-ERK-ELK1 signaling mechanism. PMID:25028509

  8. Bankruptcy Cascades in Interbank Markets

    PubMed Central

    Tedeschi, Gabriele; Mazloumian, Amin; Gallegati, Mauro; Helbing, Dirk

    2012-01-01

    We study a credit network and, in particular, an interbank system with an agent-based model. To understand the relationship between business cycles and cascades of bankruptcies, we model a three-sector economy with goods, credit and interbank market. In the interbank market, the participating banks share the risk of bad debits, which may potentially spread a bank’s liquidity problems through the network of banks. Our agent-based model sheds light on the correlation between bankruptcy cascades and the endogenous economic cycle of booms and recessions. It also demonstrates the serious trade-off between, on the one hand, reducing risks of individual banks by sharing them and, on the other hand, creating systemic risks through credit-related interlinkages of banks. As a result of our study, the dynamics underlying the meltdown of financial markets in 2008 becomes much better understandable. PMID:23300760

  9. Cascade Chaotic System With Applications.

    PubMed

    Zhou, Yicong; Hua, Zhongyun; Pun, Chi-Man; Chen, C L Philip

    2015-09-01

    Chaotic maps are widely used in different applications. Motivated by the cascade structure in electronic circuits, this paper introduces a general chaotic framework called the cascade chaotic system (CCS). Using two 1-D chaotic maps as seed maps, CCS is able to generate a huge number of new chaotic maps. Examples and evaluations show the CCS's robustness. Compared with corresponding seed maps, newly generated chaotic maps are more unpredictable and have better chaotic performance, more parameters, and complex chaotic properties. To investigate applications of CCS, we introduce a pseudo-random number generator (PRNG) and a data encryption system using a chaotic map generated by CCS. Simulation and analysis demonstrate that the proposed PRNG has high quality of randomness and that the data encryption system is able to protect different types of data with a high-security level. PMID:25373135

  10. Bankruptcy cascades in interbank markets.

    PubMed

    Tedeschi, Gabriele; Mazloumian, Amin; Gallegati, Mauro; Helbing, Dirk

    2012-01-01

    We study a credit network and, in particular, an interbank system with an agent-based model. To understand the relationship between business cycles and cascades of bankruptcies, we model a three-sector economy with goods, credit and interbank market. In the interbank market, the participating banks share the risk of bad debits, which may potentially spread a bank's liquidity problems through the network of banks. Our agent-based model sheds light on the correlation between bankruptcy cascades and the endogenous economic cycle of booms and recessions. It also demonstrates the serious trade-off between, on the one hand, reducing risks of individual banks by sharing them and, on the other hand, creating systemic risks through credit-related interlinkages of banks. As a result of our study, the dynamics underlying the meltdown of financial markets in 2008 becomes much better understandable. PMID:23300760

  11. Lens Coupled Quantum Cascade Laser

    NASA Technical Reports Server (NTRS)

    Hu, Qing (Inventor); Lee, Alan Wei Min (Inventor)

    2013-01-01

    Terahertz quantum cascade (QC) devices are disclosed that can operate, e.g., in a range of about 1 THz to about 10 THz. In some embodiments, QC lasers are disclosed in which an optical element (e.g., a lens) is coupled to an output facet of the laser's active region to enhance coupling of the lasing radiation from the active region to an external environment. In other embodiments, terahertz amplifier and tunable terahertz QC lasers are disclosed.

  12. Determining the Optimum Dietary Tryptophan to Lysine Ratio in Growing Pigs Fed Diets Formulated with Hhigher Levels of Other Essential Amino Acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies on amino acid (AA) ratios require the first limiting AA (generally Lys) to be set below the requirement estimate. Graded levels of the AA being investigated are then fed to determine the required ratio. Essential AA (EAA) not under investigation are often set at their presumed requirement ra...

  13. Cascade DNA nanomachine and exponential amplification biosensing.

    PubMed

    Xu, Jianguo; Wu, Zai-Sheng; Shen, Weiyu; Xu, Huo; Li, Hongling; Jia, Lee

    2015-11-15

    DNA is a versatile scaffold for the assembly of multifunctional nanostructures, and potential applications of various DNA nanodevices have been recently demonstrated for disease diagnosis and treatment. In the current study, a powerful cascade DNA nanomachine was developed that can execute the exponential amplification of p53 tumor suppressor gene. During the operation of the newly-proposed DNA nanomachine, dual-cyclical nucleic acid strand-displacement polymerization (dual-CNDP) was ingeniously introduced, where the target trigger is repeatedly used as the fuel molecule and the nicked fragments are dramatically accumulated. Moreover, each displaced nicked fragment is able to activate the another type of cyclical strand-displacement amplification, increasing exponentially the value of fluorescence intensity. Essentially, one target binding event can induce considerable number of subsequent reactions, and the nanodevice was called cascade DNA nanomachine. It can implement several functions, including recognition element, signaling probe, polymerization primer and template. Using the developed autonomous operation of DNA nanomachine, the p53 gene can be quantified in the wide concentration range from 0.05 to 150 nM with the detection limit of 50 pM. If taking into account the final volume of mixture, the detection limit is calculated as lower as 6.2 pM, achieving an desirable assay ability. More strikingly, the mutant gene can be easily distinguished from the wild-type one. The proof-of-concept demonstrations reported herein is expected to promote the development and application of DNA nanomachine, showing great potential value in basic biology and medical diagnosis. PMID:26042874

  14. Age Differences of Salivary Alpha-Amylase Levels of Basal and Acute Responses to Citric Acid Stimulation Between Chinese Children and Adults

    PubMed Central

    Yang, Ze-Min; Chen, Long-Hui; Zhang, Min; Lin, Jing; Zhang, Jie; Chen, Wei-Wen; Yang, Xiao-Rong

    2015-01-01

    It remains unclear how salivary alpha-amylase (sAA) levels respond to mechanical stimuli in different age groups. In addition, the role played by the sAA gene (AMY1) copy number and protein expression (glycosylated and non-glycosylated) in sAA activity has also been rarely reported. In this study, we analyzed saliva samples collected before and after citric acid stimulation from 47 child and 47 adult Chinese subjects. We observed that adults had higher sAA activity and sAA glycosylated levels (glycosylated sAA amount/total sAA amount) in basal and stimulated saliva when compared with children, while no differences were found in total or glycosylated sAA amount between them. Interestingly, adults showed attenuated sAA activity levels increase over those of children after stimulation. Correlation analysis showed that total sAA amount, glycosylated sAA amount, and AMY1 copy number × total sAA amount were all positively correlated with sAA activity before and after stimulation in both groups. Interestingly, correlation r between sAA levels (glycosylated sAA amount and total sAA amount) and sAA activity decreased after stimulation in children, while adults showed an increase in correlation r. In addition, the correlation r between AMY1 copy number × total sAA amount and sAA activity was higher than that between AMY1 copy number, total sAA amount, and sAA activity, respectively. Taken together, our results suggest that total sAA amount, glycosylated sAA amount, and the positive interaction between AMY1 copy number and total sAA amount are crucial in influencing sAA activity before and after stimulation in children and adults. PMID:26635626

  15. AA amyloidosis in vaccinated growing chickens.

    PubMed

    Murakami, T; Inoshima, Y; Sakamoto, E; Fukushi, H; Sakai, H; Yanai, T; Ishiguro, N

    2013-01-01

    Systemic amyloid-A (AA) amyloidosis in birds occurs most frequently in waterfowl such as Pekin ducks. In chickens, AA amyloidosis is observed as amyloid arthropathy. Outbreaks of systemic amyloidosis in flocks of layers are known to be induced by repeated inflammatory stimulation, such as those resulting from multiple vaccinations with oil-emulsified bacterins. Outbreaks of fatal AA amyloidosis were observed in growing chickens in a large scale poultry farm within 3 weeks of vaccination with multiple co-administered vaccines. This study documents the histopathological changes in tissues from these birds. Amyloid deposits were also observed at a high rate in the tissues of apparently healthy chickens. Vaccination should therefore be considered as a potential risk factor for the development of AA amyloidosis in poultry. PMID:23570943

  16. AAS 228: Day 3 morning

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Plenary Session 2015 Newton Lacy Pierce Prize Lecture: The Elephant in the Room: Effects of Distant, Massive Companions on Planetary System Architectures (by Leonardo dos Santos)The first session on Wednesday at 228th AAS Meeting was the Newton Lacy Pierce Prize Lecture by Heather Knutson (California Institute of Technology). This talk featured a broad range of research efforts on exoplanets, with the main focus on how we study the composition of their atmospheres, and how multi-body interactions carve the structure of the planetary systems we observe.One of her first points is the well-known idea that the Solar System is an oddball, compared to the exoplanet systems we have found so far: most of these systems contain hot Jupiters and mini-Neptunes at very close-in orbits around their host stars. Moreover, even when studying their transmission spectra, it is difficult to know the exact composition of their atmospheres.Knutson: it is difficult to constrain atmospheric composition of exoplanets (H-poor or H-rich+clouds?) #aas228pic.twitter.com/LdyN4o9RC7 astrobites (@astrobites) June 15, 2016The main proposal on how these systems formed is the migration scenario. In order to validate this idea, Dr. Knutson and her group The Friends of Hot Jupiters study systems with close-in gas giants and their frequency of binary companions, which are supposed to be the main culprits causing gas-giant migration. They found that approximately half of the observed systems have long-distance companions, providing strong validation of the migration scenario. Moreover, Dr. Knutson speculates that wide binaries have more

  17. AAS 228: Day 3 morning

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Plenary Session 2015 Newton Lacy Pierce Prize Lecture: The Elephant in the Room: Effects of Distant, Massive Companions on Planetary System Architectures (by Leonardo dos Santos)The first session on Wednesday at 228th AAS Meeting was the Newton Lacy Pierce Prize Lecture by Heather Knutson (California Institute of Technology). This talk featured a broad range of research efforts on exoplanets, with the main focus on how we study the composition of their atmospheres, and how multi-body interactions carve the structure of the planetary systems we observe.One of her first points is the well-known idea that the Solar System is an oddball, compared to the exoplanet systems we have found so far: most of these systems contain hot Jupiters and mini-Neptunes at very close-in orbits around their host stars. Moreover, even when studying their transmission spectra, it is difficult to know the exact composition of their atmospheres.Knutson: it is difficult to constrain atmospheric composition of exoplanets (H-poor or H-rich+clouds?) #aas228pic.twitter.com/LdyN4o9RC7 astrobites (@astrobites) June 15, 2016The main proposal on how these systems formed is the migration scenario. In order to validate this idea, Dr. Knutson and her group The Friends of Hot Jupiters study systems with close-in gas giants and their frequency of binary companions, which are supposed to be the main culprits causing gas-giant migration. They found that approximately half of the observed systems have long-distance companions, providing strong validation of the migration scenario. Moreover, Dr. Knutson speculates that wide binaries have more

  18. Dietary arachidonic acid dose-dependently increases the arachidonic acid concentration in human milk.

    PubMed

    Weseler, Antje R; Dirix, Chantal E H; Bruins, Maaike J; Hornstra, Gerard

    2008-11-01

    Lactation hampers normalization of the maternal arachidonic acid (AA) status, which is reduced after pregnancy and can further decline by the presently recommended increased consumption of (n-3) long-chain PUFA [(n-3) LCPUFA]. This may be unfavorable for breast-fed infants, because they also require an optimum supply of (n-6) LCPUFA. We therefore investigated the LCPUFA responses in nursing mothers upon increased consumption of AA and (n-3) LCPUFA. In a parallel, double-blind, controlled trial, lactating women received for 8 wk no extra LCPUFA (control group, n = 8), 200 (low AA group, n = 9), or 400 (high AA group, n = 8) mg/d AA in combination with (n-3) LCPUFA [320 mg/d docosahexaenoic acid (DHA), 80 mg/d eicosapentaenoic acid, and 80 mg/d other (n-3) fatty acids], or this dose of (n-3) LCPUFA alone [DHA + eicosapentaenoic acid group, n = 8]. Relative concentrations of AA, DHA, and sums of (n-6) and (n-3) LCPUFA were measured in milk total lipids (TL) and erythrocyte phospholipids (PL) after 2 and 8 wk and changes were compared by ANCOVA. The combined consumption of AA and (n-3) LCPUFA caused dose-dependent elevations of AA and total (n-6) LCPUFA concentrations in milk TL and did not significantly affect the DHA and total (n-3) LCPUFA increases caused by (n-3) LCPUFA supplementation only. This latter treatment did not significantly affect breast milk AA and total (n-6) LCPUFA concentrations. AA and DHA concentrations in milk TL and their changes were strongly and positively correlated with their corresponding values in erythrocyte PL (r(2) = 0.27-0.50; P AA in addition to extra (n-3) LCPUFA dose dependently increased the AA concentration of their milk TL. PMID:18936218

  19. Cascade defense via routing in complex networks

    NASA Astrophysics Data System (ADS)

    Xu, Xiao-Lan; Du, Wen-Bo; Hong, Chen

    2015-05-01

    As the cascading failures in networked traffic systems are becoming more and more serious, research on cascade defense in complex networks has become a hotspot in recent years. In this paper, we propose a traffic-based cascading failure model, in which each packet in the network has its own source and destination. When cascade is triggered, packets will be redistributed according to a given routing strategy. Here, a global hybrid (GH) routing strategy, which uses the dynamic information of the queue length and the static information of nodes' degree, is proposed to defense the network cascade. Comparing GH strategy with the shortest path (SP) routing, efficient routing (ER) and global dynamic (GD) routing strategies, we found that GH strategy is more effective than other routing strategies in improving the network robustness against cascading failures. Our work provides insight into the robustness of networked traffic systems.

  20. The Changing Shape of the AAS

    NASA Astrophysics Data System (ADS)

    Boyce, P. B.

    1995-12-01

    What is the astronomical workforce like? Where do astronomers work? How old are they? How permanent are their jobs? As we move into a period of increased uncertainty in federal funding for science it is important to know the answers to these questions. There are four sources of information for answers: 1. Information from the AAS membership database. 2. A survey of the AAS membership. 3. Surveys of samples of the AAS membership by AIP. 4. Information from the NRC and NSF. We have gender and age data from 1. A survey of the AAS membershWe will have age and gender data from 1. We will complete and analyze a new membersip survey shortly. The latest AIP data is from 1994. They will do a new sample in 1996. Much of the NRC data is aggregated with physics, and that does not give information about astronomers. Nevertheless, we do have some interesting information. The ages and genders of AAS members are available for 1972, 1990 and 1995. The time sequence provides an interesting look at the AAS. For instance, from 1990 to 1995 the number of women in each 5-year age group below the the age of 65 increased. Contrary to popular perception, women are not leaving the Society as they get older. However, the number of men actually decreased in each age group above the age of 35. This and other interesting trends will be discussed.

  1. Quantum cascade lasers with dual-wavelength interdigitated cascades

    NASA Astrophysics Data System (ADS)

    Mosely, Trinesha S.; Straub, Axel; Gmachl, Claire; Colombelli, Raffaele; Troccoli, Mariano; Capasso, Federico; Sivco, Deborah L.; Cho, Alfred Y.

    2002-03-01

    A quantum cascade (QC) laser with a dual-wavelength interdigitated cascade is presented. Its active core consists of a stack of active regions and injectors designed for emission at one wavelength (8.0 μm) interleaved with a second stack emitting at a substantially different wavelength (9.5 μm), and the two injectors were designed to either bridge the 8.0 μm active region to the 9.5 μm one, or vice versa. Clear two-wavelength laser action is observed, demonstrating the viability of this approach to achieve multi-wavelength laser emission in the mid-infrared. Aside from providing two-wavelength operation, this laser design can also be used to test the role of charge transport in the injectors, which customarily bridge successive active regions together. We will present early results of this study. The work was partly supported by DARPA/US ARO under contract number DAAD19-00-C-0096. A. S. acknowledges the support of the Deutsche Studienstiftung. T. S. M. present address: Southern University and A&M College, Baton Rouge, LA.

  2. How sesquiterpenes modulate signaling cascades in cancers.

    PubMed

    Jabeen, S; Qureshi, M Z; Attar, R; Aslam, A; Kanwal, S; Khalid, S; Qureshi, J M; Aras Perk, A; Farooqi, A A; Ismail, M

    2016-01-01

    Data obtained from high-throughput technologies has started to shed light on the interplay between signal transduction cascades and chromatin modifications thus adding another layer of complexity to the already complex regulation of the protein network. Based on the insights gleaned from almost a decade of research, it has now been convincingly revealed that sesquiterpenes effectively modulated different intracellular signaling cascades in different cancers. In this review we summarize how sesquiterpenes mediated Wnt, Shh, Notch and TRAIL induced signaling cascades. PMID:27453282

  3. A Cascade-Reaction Nanoreactor Composed of a Bifunctional Molecularly Imprinted Polymer that Contains Pt Nanoparticles.

    PubMed

    Wang, Jiao; Zhu, Maiyong; Shen, Xiaojuan; Li, Songjun

    2015-05-11

    This study was aimed at addressing the present challenge of cascade reactions, namely, how to furnish the catalysts with desired and hierarchical catalytic ability. This issue was addressed by constructing a cascade-reaction nanoreactor made of a bifunctional molecularly imprinted polymer containing acidic catalytic sites and Pt nanoparticles. The acidic catalytic sites within the imprinted polymer allowed one specified reaction, whereas the encapsulated Pt nanoparticles were responsible for another coupled reaction. To that end, the unique imprinted polymer was fabricated by using two well-coupled templates, that is, 4-nitrophenyl acetate and 4-nitrophenol. The catalytic hydrolysis of the former compound at the acidic catalytic sites led to the formation of the latter compound, which was further reduced by the encapsulated Pt nanoparticles to 4-aminophenol. Therefore, this nanoreactor demonstrated a catalytic-cascade ability. This protocol opens up the opportunity to develop functional catalysts for complicated chemical processes. PMID:25846700

  4. Cascade photo production at CLAS

    SciTech Connect

    Goetz, John; Hicks, Kenneth H.

    2014-09-01

    The famous discovery of the Omega in 1964 put the quark model on firm ground and since then a lot of effort has been spent on mapping out the baryonic and mesonic states. Over the following decades, many excited baryons with light quarks (up, down and strange) have been measured, but by most predictions, only a small percentage of those expected have been found. In this talk, I will discuss a newly developing technique using an (unflavored) photon beam to excite protons to doubly-strange "Cascade" (Xi) states. Advantages of such an experiment and associated difficulties will be presented, along with recent results from the CLAS detector at Jefferson Lab in Virginia.

  5. Logic synthesis of cascade circuits

    NASA Astrophysics Data System (ADS)

    Zakrevskii, A. D.

    The work reviews aspects of the logic design of cascade circuits, particularly programmable logic matrices. Effective methods for solving various problems of the analysis and synthesis of these devices are examined; these methods are based on a matrix representation of the structure of these devices, and a vector-matrix interpretation of certain aspects of Boolean algebra. Particular consideration is given to the theory of elementary matrix circuits, methods for the minimization of Boolean functions, the synthesis of programmable logic matrices, multilevel combinational networks, and the development of automata with memory.

  6. AAS 228: Day 1 afternoon

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Plenary Session: From Space Archeology to Serving the World Today: A 20-year Journey from the Jungles of Guatemala to a Network of Satellite Remote Sensing Facilities Around the World(by Michael Zevin)In the conferences second plenary session, NASAs Daniel Irwin turned the eyes of the conference back to Earth by highlighting the huge impact that NASA missions play in protecting and developing our own planet.Daniel Irwin: using satellite imagery to detect differences in vegetation and find ancient Mayan cities. #aas228 pic.twitter.com/9LFPQdCHTM astrobites (@astrobites) June 13, 2016Irwin came to be involved in NASA through his work mapping Guatemalan jungles, where he would spend 22 days at a time exploring the treacherous jungles on foot armed with a 1st generation GPS, a compass, and a machete. A colleague introduced Irwin to the satellite imagery thathe was exploring, demonstratinghow these images are a strong complement to field work. The sharing of this satellite data with nearby villages helped to show the encroachment of agriculture and the necessity of connecting space to the village. Satellite imagery also played a role in archeological endeavors, uncovering dozens of Mayan cities that have been buried for over a millennia by vegetation, and it provided evidence that the fall of the Mayan civilization may have been due to massive deforestation that ledto drought.Glacial retreat in Chile imaged by ISERV.Irwin displayed the constellation of NASAs Earth-monitoring satellites that have played an integral role in conserving our planet and alerting the world of natural disasters. He also showed

  7. WHISTLER TURBULENCE FORWARD CASCADE VERSUS INVERSE CASCADE: THREE-DIMENSIONAL PARTICLE-IN-CELL SIMULATIONS

    SciTech Connect

    Chang, Ouliang; Gary, S. Peter; Wang, Joseph E-mail: pgary@lanl.gov

    2015-02-20

    We present the results of the first fully three-dimensional particle-in-cell simulations of decaying whistler turbulence in a magnetized, homogeneous, collisionless plasma in which both forward cascades to shorter wavelengths, and inverse cascades to longer wavelengths are allowed to proceed. For the electron beta β {sub e} = 0.10 initial value considered here, the early-time rate of inverse cascade is very much smaller than the rate of forward cascade, so that at late times the fluctuation energy in the regime of the inverse cascade is much weaker than that in the forward cascade regime. Similarly, the wavevector anisotropy in the inverse cascade regime is much weaker than that in the forward cascade regime.

  8. Tri-bimaximal Mixing from Cascades

    SciTech Connect

    Takahashi, Ryo

    2008-11-23

    We investigate fermion mass matrices of the cascade form which lead to the tri-bimaximal mixing in the lepton sector. The cascade neutrino matrix predicts a parameter-independent relation among the observables, which are the neutrino mixing angles and mass squared differences. The relation predicts that the atmospheric neutrino mixing angle is close to maximal. We also study phenomenological aspect of the cascade form in supersymmetric theory, which are lepton flavor violation and thermal leptogenesis. A dynamical realivation of the cascade mass matrix are also presented in U(1) flavor theory.

  9. Lie cascades and Random Dynamical Systems

    NASA Astrophysics Data System (ADS)

    Schertzer, D.; Lovejoy, S.; Tchiguirinskaia, I.

    2009-04-01

    Lie cascades were defined as a broad generalization of scalar cascades (Schertzer and Lovejoy 1995, Tchiguirinskaia and Schertzer, 1996) with the help of (infinitesimal) sub-generators being white noise vector fields on manifolds, instead of being white noise scalar fields on vector spaces. Lie cascades were thus closely related to stochastic flows on manifolds as defined by Kunita (1990). However, the concept of random dynamical systems (Arnold,1998) allows to make a closer and simpler connection between stochastic differential equations and the dynamical system approach. In this talk, we point out some relationships between Lie cascades and random dynamical systems, and therefore to dynamical system approach.

  10. Contingency Analysis of Cascading Line Outage Events

    SciTech Connect

    Thomas L Baldwin; Magdy S Tawfik; Miles McQueen

    2011-03-01

    As the US power systems continue to increase in size and complexity, including the growth of smart grids, larger blackouts due to cascading outages become more likely. Grid congestion is often associated with a cascading collapse leading to a major blackout. Such a collapse is characterized by a self-sustaining sequence of line outages followed by a topology breakup of the network. This paper addresses the implementation and testing of a process for N-k contingency analysis and sequential cascading outage simulation in order to identify potential cascading modes. A modeling approach described in this paper offers a unique capability to identify initiating events that may lead to cascading outages. It predicts the development of cascading events by identifying and visualizing potential cascading tiers. The proposed approach was implemented using a 328-bus simplified SERC power system network. The results of the study indicate that initiating events and possible cascading chains may be identified, ranked and visualized. This approach may be used to improve the reliability of a transmission grid and reduce its vulnerability to cascading outages.

  11. Cascade control and defense in complex networks.

    PubMed

    Motter, Adilson E

    2004-08-27

    Complex networks with a heterogeneous distribution of loads may undergo a global cascade of overload failures when highly loaded nodes or edges are removed due to attacks or failures. Since a small attack or failure has the potential to trigger a global cascade, a fundamental question regards the possible strategies of defense to prevent the cascade from propagating through the entire network. Here we introduce and investigate a costless strategy of defense based on a selective further removal of nodes and edges, right after the initial attack or failure. This intentional removal of network elements is shown to drastically reduce the size of the cascade. PMID:15447153

  12. Dynamics and structure of energetic displacement cascades

    SciTech Connect

    Averback, R.S.; Diaz de la Rubia, T.; Benedek, R.

    1987-12-01

    This paper summarizes recent progress in the understanding of energetic displacement cascades and the primary state of damage in metals. On the theoretical side, the availability of supercomputers has greatly enhanced our ability to simulate cascades by molecular dynamics. Recent application of this simulation technique to Cu and Ni provides new insight into the dynamics of cascade processes. On the experimental side, new data on ion beam mixing and in situ electron microscopy studies of ion damage at low temperatures reveal the role of the thermodynamic properties of the material on cascade dynamics and structure. 38 refs., 9 figs.

  13. AAS 228: Day 1 afternoon

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Plenary Session: From Space Archeology to Serving the World Today: A 20-year Journey from the Jungles of Guatemala to a Network of Satellite Remote Sensing Facilities Around the World(by Michael Zevin)In the conferences second plenary session, NASAs Daniel Irwin turned the eyes of the conference back to Earth by highlighting the huge impact that NASA missions play in protecting and developing our own planet.Daniel Irwin: using satellite imagery to detect differences in vegetation and find ancient Mayan cities. #aas228 pic.twitter.com/9LFPQdCHTM astrobites (@astrobites) June 13, 2016Irwin came to be involved in NASA through his work mapping Guatemalan jungles, where he would spend 22 days at a time exploring the treacherous jungles on foot armed with a 1st generation GPS, a compass, and a machete. A colleague introduced Irwin to the satellite imagery thathe was exploring, demonstratinghow these images are a strong complement to field work. The sharing of this satellite data with nearby villages helped to show the encroachment of agriculture and the necessity of connecting space to the village. Satellite imagery also played a role in archeological endeavors, uncovering dozens of Mayan cities that have been buried for over a millennia by vegetation, and it provided evidence that the fall of the Mayan civilization may have been due to massive deforestation that ledto drought.Glacial retreat in Chile imaged by ISERV.Irwin displayed the constellation of NASAs Earth-monitoring satellites that have played an integral role in conserving our planet and alerting the world of natural disasters. He also showed

  14. Intermolecular interaction between Cry2Aa and Cyt1Aa and its effect on larvicidal activity against Culex quinquefasciatus.

    PubMed

    Bideshi, Dennis K; Waldrop, Greer; Fernandez-Luna, Maria Teresa; Diaz-Mendoza, Mercedes; Wirth, Margaret C; Johnson, Jeffrey J; Park, Hyun-Woo; Federici, Brian A

    2013-08-01

    The Cyt1Aa protein of Bacillus thuringiensis susbp. israelensis elaborates demonstrable toxicity to mosquito larvae, but more importantly, it enhances the larvicidal activity of this species Cry proteins (Cry11Aa, Cry4Aa, and Cry4Ba) and delays the phenotypic expression of resistance to these that has evolved in Culex quinquefasciatus. It is also known that Cyt1Aa, which is highly lipophilic, synergizes Cry11Aa by functioning as a surrogate membrane-bound receptor for the latter protein. Little is known, however, about whether Cyt1Aa can interact similarly with other Cry proteins not primarily mosquitocidal; for example, Cry2Aa, which is active against lepidopteran larvae, but essentially inactive or has very low toxicity to mosquito larvae. Here we demonstrate by ligand binding and enzyme-linked immunosorbent assays that Cyt1Aa and Cry2Aa form intermolecular complexes in vitro, and in addition show that Cyt1Aa facilitates binding of Cry2Aa throughout the midgut of C. quinquefasciatus larvae. As Cry2Aa and Cry11Aa share structural similarity in domain II, the interaction between Cyt1Aa and Cry2Aa could be a result of a similar mechanism previously proposed for Cry11Aa and Cyt1Aa. Finally, despite the observed interaction between Cry2Aa and Cyt1Aa, only a 2-fold enhancement in toxicity resulted against C. quinquefasciatus. Regardless, our results suggest that Cry2Aa could be a useful component of mosquitocidal endotoxin complements being developed for recombinant strains of B. thuringiensis subsp. israelensis and B. sphaericus aimed at improving the efficacy of commercial products and avoiding resistance. PMID:23727800

  15. Cascade decays of hollow ions

    SciTech Connect

    Omar, G. ); Hahn, Y. )

    1991-05-01

    A multiple-electron-emission process for atoms with one or more inner-shell vacancies is treated using the radiative- and Auger-electron-emission cascade model, in which inner-shell holes are assumed to decay by sequentially emitting radiations and/or Auger electrons. Such hollow ions are produced by synchrotron irradiation of atomic targets and in ion-surface interactions with multiple-electron transfers. The final charge-state distribution is determined by the Auger and radiative branching ratios at each stage of the decay sequence. At intermediate stages of cascade, hollow ions with more than one hole in different ionization stages are created. The Ne, Mg, and Fe{sup 14+} ions with the initial 1{ital s}, 2{ital s}, and 2{ital p} vacancies are considered in detail, and the core charge dependence of the maximum charge state is studied. The hollow Mg ion with double initial 1{ital s} holes is analyzed, and the result compared with that for the case of one 1{ital s} hole. The peak is shifted more than two units to a higher degree of ionization. The correlated shake-off and shake-up multiple-electron processes are not considered, but they are expected to cause further shifts.

  16. Lifespans of Cascade Arc volcanoes

    NASA Astrophysics Data System (ADS)

    Calvert, A. T.

    2015-12-01

    Compiled argon ages reveal inception, eruptive episodes, ages, and durations of Cascade stratovolcanoes and their ancestral predecessors. Geologic mapping and geochronology show that most Cascade volcanoes grew episodically on multiple scales with periods of elevated behavior lasting hundreds of years to ca. 100 kyr. Notable examples include the paleomag-constrained, few-hundred-year-long building of the entire 15-20 km3 Shastina edifice at Mt. Shasta, the 100 kyr-long episode that produced half of Mt. Rainier's output, and the 30 kyr-long episode responsible for all of South and Middle Sister. Despite significant differences in timing and rates of construction, total durations of active and ancestral volcanoes at discrete central-vent locations are similar. Glacier Peak, Mt. Rainier, Mt. Adams, Mt. Hood, and Mt. Mazama all have inception ages of 400-600 ka. Mt. St. Helens, Mt. Jefferson, Newberry Volcano, Mt. Shasta and Lassen Domefield have more recent inception ages of 200-300 ka. Only the Sisters cluster and Mt. Baker have established eruptive histories spanning less than 50 kyr. Ancestral volcanoes centered 5-20 km from active stratocones appear to have similar total durations (200-600 kyr), but are less well exposed and dated. The underlying mechanisms governing volcano lifecycles are cryptic, presumably involving tectonic and plumbing changes and perhaps circulation cycles in the mantle wedge, but are remarkably consistent along the arc.

  17. Physics of interband cascade lasers

    NASA Astrophysics Data System (ADS)

    Vurgaftman, I.; Bewley, W. W.; Merritt, C. D.; Canedy, C. L.; Kim, C. S.; Abell, J.; Meyer, J. R.; Kim, M.

    2012-01-01

    The interband cascade laser (ICL) is a unique device concept that combines the effective parallel connection of its multiple-quantum-well active regions, interband active transitions, and internal generation of electrons and holes at a semimetallic interface within each stage of the device. The internal generation of carriers becomes effective under bias, and the role of electrical injection is to replenish the carriers consumed by recombination processes. Major strides have been made toward fundamentally understanding the rich and intricate ICL physics, which has in turn led to dramatic improvements in the device performance. In this article, we review the physical principles of the ICL operation and designs of the active region, electron and hole injectors, and optical waveguide. The results for state-of- the-art ICLs spanning the 3-6 μm wavelength range are also briefly reviewed. The cw threshold input powers at room temperature are more than an order of magnitude lower than those for quantum cascade lasers throughout the mid-IR spectral range. This will lengthen battery lifetimes and greatly relax packaging and size/weight requirements for fielded sensing systems.

  18. N-terminal sequence of amino acids and some properties of an acid-stable alpha-amylase from citric acid-koji (Aspergillus usamii var.).

    PubMed

    Suganuma, T; Tahara, N; Kitahara, K; Nagahama, T; Inuzuka, K

    1996-01-01

    An acid-stable alpha-amylase (AA) was purified from an acidic extract of citric acid-koji (A. usamii var.). The N-terminal sequence of the first 20 amino acids of the enzyme was identical with that of AA from A. niger, but the two enzymes differed in molecular weight. HPLC analysis for identifying the anomers of products indicated that the AA hydrolyzed maltopentaose (G5) at the third glycoside bond predominantly, which differed from Taka-amylase A and the neutral alpha-amylase (NA) from the citric acid-koji. PMID:8824843

  19. IgE binding to peanut allergens is inhibited by combined D-aspartic and D-glutamic acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    D-amino acids (D-aas) are reported to bind to IgE antibodies from people with allergy and asthma. The objectives of this study were to determine if D-aas bind or inhibit IgE binding to peanut allergens, and if they are more effective than L-amino acids (L-aas) in this respect. Several D-aa cocktails...

  20. Direct-Chill Co-Casting of AA3003/AA4045 Aluminum Ingots via Fusion™ Technology

    NASA Astrophysics Data System (ADS)

    Caron, Etienne J. F. R.; Pelayo, Rosa E. Ortega; Baserinia, Amir R.; Wells, Mary A.; Weckman, David C.; Barker, Simon; Gallerneault, Mark

    2014-06-01

    Laboratory-scale experiments were conducted to cast AA3003/AA4045 clad ingots via Fusion™ Technology, a novel process developed by Novelis Inc. for the production of aluminum clad materials such as brazing sheet. Experimental results were used to validate a steady-state thermofluids model of the Fusion™ Technology co-casting process. The numerical model was able to accurately predict the temperature field within the AA3003/AA4045 clad ingot as well as the shape of the AA3003 liquid sump. The model was also used to quantify the temperature, fraction solid, and velocity fields in a clad ingot cast with an asymmetrical molten metal-feeding system. Feeding of core and clad molten metals at opposite corners of the mold was found to reduce the risks of hot spots and liquid metal breakthrough from the core sump to the clad side of the Fusion™ Technology mold. The use of a diffuser for the AA3003 core molten metal and of a vertical feeding tube for the AA4045 clad produced different flow patterns and liquid sump shapes on either side of the mold. The quality of the metallurgical bond at the core/clad interface appeared good near the clad inlet and at the ingot centerline, but poor near the edges of the ingot. SEM-EDS analysis of the chemical composition across the interface showed that a 1 to 20- μm-deep penetration of silicon from the AA4045 clad into the AA3003 core had occurred at visually acceptable interfaces, whereas silicon diffusion across poor interfaces was very limited. A study of the model-predicted fraction solid history at different points along the interface indicated that reheating of the AA3003 core is not required to form a visually acceptable metallurgical bond. However, a sufficient amount of interaction time between the solid AA3003 core shell and the silicon-rich AA4045 clad liquid is required to chemically dissolve the surface of the core and form a good metallurgical bond. An approximate dissolution depth of 750 to 1000 μm was observed along

  1. JBIR-78 and JBIR-95: phenylacetylated peptides isolated from Kibdelosporangium sp. AK-AA56.

    PubMed

    Izumikawa, Miho; Takagi, Motoki; Shin-Ya, Kazuo

    2012-02-24

    The search for metabolites of Kibdelosporangium sp. AK-AA56 resulted in the discovery of novel N-phenylacetylated peptides, JBIR-78 (1) and JBIR-95 (2). Compounds 1 and 2 were established to be N-phenylacetylated heptapeptides by extensive NMR and HRESIMS analyses. The absolute configuration of the standard amino acids including a cysteic acid moiety was determined using Marfey's method on the acid hydrolysates of 1 and 2. The relative and absolute configurations of a nonstandard amino acid, β-hydroxyleucine, were elucidated using the J-based and modified Mosher's methods, respectively. In an antimicrobial test, 1 showed antibacterial activity against Micrococcus luteus. PMID:22264203

  2. Detection of AA76, a Common Form of Amyloid A Protein, as a Way of Diagnosing AA Amyloidosis.

    PubMed

    Sato, Junji; Okuda, Yasuaki; Kuroda, Takeshi; Yamada, Toshiyuki

    2016-03-01

    Reactive amyloid deposits consist of amyloid A (AA) proteins, the degradation products of serum amyloid A (SAA). Since the most common species of AA is the amino terminal portion produced by cleavage between residues 76 and 77 of SAA (AA76), the presence of AA76 in tissues could be a consequence of AA amyloid deposition. This study assessed the diagnostic significance of the detection of AA76 for AA amyloidosis using two different approaches. Biopsy specimens (n=130 from 54 subjects) from gastroduodenal mucosa or abdominal fat (n=9 from 9 subjects) of patients who had already been diagnosed with or were suspected of having AA amyloidosis were used. Fixed mucosal sections were subjected to immunohistochemistry using a newly developed antibody recognizing the carboxyl terminal end of AA76 (anti-AA76). The non-fixed materials from gastroduodenal mucosa or abdominal fat were subjected to immunoblotting for detection of the size of AA76. Among the gastroduodenal specimens (n=115) from already diagnosed patients, the positive rates of Congo red staining, immunohistochemistry using anti-AA76, and immunoblotting were 68.4%, 73.0%, and 92.2%, respectively. The anti-AA76 did not stain the supposed SAA in the blood or leakage, which was stained by anti-SAA antibody. AA76 was not detected either by immunohistochemistry or by immunoblot in the materials from patients in whom AA amyloidosis had been ruled out. In the abdominal fat, the immunoblot detected AA76 in 8 materials from 8 already diagnosed patients and did not in 1 patient whose gastroduodenal mucosa was negative. In conclusion, the detection of AA76 may alter the ability to diagnose AA amyloidosis. In immunohistochemistry for fixed specimens, the new anti-AA76 antibody can improve the specificity. Immunoblot for non-fixed materials, which can considerably improve the sensitivity, should be beneficial for small materials like abdominal fat. PMID:27098620

  3. Cascade Harvest’ red raspberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cascade Harvest’ is a new floricane fruiting raspberry cultivar (Rubus idaeus L.) jointly released by Washington State University (WSU), Oregon State University (OSU) and the U.S. Department of Agriculture (USDA). ‘Cascade Harvest’ produces a high yield of large, firm fruit suited to machine harves...

  4. Aerodynamics of a linear oscillating cascade

    NASA Technical Reports Server (NTRS)

    Buffum, Daniel H.; Fleeter, Sanford

    1990-01-01

    The steady and unsteady aerodynamics of a linear oscillating cascade are investigated using experimental and computational methods. Experiments are performed to quantify the torsion mode oscillating cascade aerodynamics of the NASA Lewis Transonic Oscillating Cascade for subsonic inlet flowfields using two methods: simultaneous oscillation of all the cascaded airfoils at various values of interblade phase angle, and the unsteady aerodynamic influence coefficient technique. Analysis of these data and correlation with classical linearized unsteady aerodynamic analysis predictions indicate that the wind tunnel walls enclosing the cascade have, in some cases, a detrimental effect on the cascade unsteady aerodynamics. An Euler code for oscillating cascade aerodynamics is modified to incorporate improved upstream and downstream boundary conditions and also the unsteady aerodynamic influence coefficient technique. The new boundary conditions are shown to improve the unsteady aerodynamic influence coefficient technique. The new boundary conditions are shown to improve the unsteady aerodynamic predictions of the code, and the computational unsteady aerodynamic influence coefficient technique is shown to be a viable alternative for calculation of oscillating cascade aerodynamics.

  5. MDCT evaluation of acute aortic syndrome (AAS).

    PubMed

    Valente, Tullio; Rossi, Giovanni; Lassandro, Francesco; Rea, Gaetano; Marino, Maurizio; Muto, Maurizio; Molino, Antonio; Scaglione, Mariano

    2016-05-01

    Non-traumatic acute thoracic aortic syndromes (AAS) describe a spectrum of life-threatening aortic pathologies with significant implications on diagnosis, therapy and management. There is a common pathway for the various manifestations of AAS that eventually leads to a breakdown of the aortic intima and media. Improvements in biology and health policy and diffusion of technology into the community resulted in an associated decrease in mortality and morbidity related to aortic therapeutic interventions. Hybrid procedures, branched and fenestrated endografts, and percutaneous aortic valves have emerged as potent and viable alternatives to traditional surgeries. In this context, current state-of-the art multidetector CT (MDCT) is actually the gold standard in the emergency setting because of its intrinsic diagnostic value. Management of acute aortic disease has changed with the increasing realization that endovascular therapies may offer distinct advantages in these situations. This article provides a summary of AAS, focusing especially on the MDCT technique, typical and atypical findings and common pitfalls of AAS, as well as recent concepts regarding the subtypes of AAS, consisting of aortic dissection, intramural haematoma, penetrating atherosclerotic ulcer and unstable aortic aneurysm or contained aortic rupture. MDCT findings will be related to pathophysiology, timing and management options to achieve a definite and timely diagnostic and therapeutic definition. In the present article, we review the aetiology, pathophysiology, clinical presentation, outcomes and therapeutic approaches to acute aortic syndromes. PMID:27033344

  6. Amino acid nitrogen isotopic composition patterns in lacustrine sedimenting matter

    NASA Astrophysics Data System (ADS)

    Carstens, Dörte; Lehmann, Moritz F.; Hofstetter, Thomas B.; Schubert, Carsten J.

    2013-11-01

    Amino acids (AAs) comprise a large fraction of organic nitrogen (N) in plankton and sedimenting matter. Aquatic studies of organic N compounds in general and of AAs in particular, mostly concentrate on marine environments. In order to study the cycling and fate of organic N and AAs in lakes, we measured the N isotopic composition (δ15N) of bulk organic matter (OM) and of single hydrolysable AAs in sediment trap and sediment samples from two Swiss lakes with contrasting trophic state: Lake Brienz, an oligotrophic lake with an oxic water column, and Lake Zug a eutrophic, meromictic lake. We also measured the N isotopic composition of water column nitrate, the likely inorganic N source during biosynthesis in both lakes. The δ15N-AA patterns found for the sediment trap material were consistent with published δ15N-AA data for marine plankton. The AA composition and primary δ15N-AA signatures are preserved until burial in the sediments. During early sedimentary diagenesis, the δ15N values of single AAs appear to increase, exceeding those of the bulk OM. This increase in δ15N-AA is paralleled by a decreased contribution of AAs to the total OM pool with progressed degradation, suggesting preferential AA degradation associated with a significant N isotope fractionation. Indicators for trophic level based on δ15N-AAs were determined, for the first time in lacustrine systems. In our samples, the trophic AAs were generally enriched in 15N compared to source AAs and higher trophic δ15N-AA values in Lake Zug were consistent with a higher trophic level of the bulk biomass compared to Lake Brienz. Especially the difference between average trophic δ15N-AAs and average source δ15N-AAs was sensitive to the trophic states of the two lakes. A proxy for total heterotrophic AA re-synthesis (ΣV), which is strongly associated with heterotrophic microbial reworking of the OM, was calculated based on δ15N values of trophic AAs. Higher ΣV in Lake Brienz indicate enhanced

  7. Ascorbic acid, cognitive function, and Alzheimer's disease: a current review and future direction.

    PubMed

    Bowman, Gene L

    2012-01-01

    This narrative review appraises the human and animal studies implicating ascorbic acid (AA) in normal cognitive function and Alzheimer's disease. A research framework for how nutrition affects brain aging is proposed with emphasis on AA intake, status, metabolism, and transport into brain tissue. A final synopsis highlights areas for future research regarding AA nourishment and healthy brain aging. PMID:22419527

  8. Insulin and amino acids stimulate whole body protein synthesis in neonates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insulin and amino acids (AA) stimulate muscle protein synthesis in neonatal pigs. To determine the effects of insulin and AA on whole body protein turnover, hyperinsulinemic (0 and 100 ng/(kg[0.66]/min))-euglycemic-AA clamps were performed during euaminoacidemia or hyperaminoacidemia in fasted 7-d-...

  9. 2. LOOKING EAST AT PARKING AREA BETWEEN TAMARACK AND CASCADE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. LOOKING EAST AT PARKING AREA BETWEEN TAMARACK AND CASCADE CREEK BRIDGES. RAILING AT RIGHT EDGE IS THE EAST END OF TAMARACK BRIDGE. - Cascade Creek Bridge, Spanning Cascade Creek on New Big Oak Flat Road, Yosemite Village, Mariposa County, CA

  10. Cascade Error Projection: An Efficient Hardware Learning Algorithm

    NASA Technical Reports Server (NTRS)

    Duong, T. A.

    1995-01-01

    A new learning algorithm termed cascade error projection (CEP) is presented. CEP is an adaption of a constructive architecture from cascade correlation and the dynamical stepsize of A/D conversion from the cascade back propagation algorithm.

  11. Impact of Q139R substitution of MEB4-Cry2Aa toxin on its stability, accessibility and toxicity against Ephestia kuehniella.

    PubMed

    Nouha, Abdelmalek; Sameh, Sellami; Fakher, Frikha; Slim, Tounsi; Souad, Rouis

    2015-11-01

    The Bacillus thuringiensis subsp. kurstaki strain MEB4 was previously found to be highly toxic to Ephestia kuehniella. SDS-PAGE analysis of the recombinant strain DH5α (pBS-cry2Aa-MEB4) showed that Cry2Aa-MEB4 delta-endotoxins were forming inclusion bodies, and were 2.75 fold more toxic towards E. kuehniella than those of Cry2Aa-BNS3. Besides to the 65kDa active toxin, proteolysis activation of Cry2Aa-BNS3 protein with E. kuehniella midgut juice generated an extra proteolysis form of 49kDa, which was the result of another chymotrypsin cleavage located in Leu144. The amino acid sequences alignment of Cry2Aa-MEB4 and Cry2Aa-BNS3 showed that among the different 15 amino acids, the Q139R substitution was found to be interesting. In fact, due to its presence within the loop α3-α4, the chymotrypsin-like protease was unable to access to its site in Cry2Aa-MEB4, resulting to the production of only the 65kDa form. The accessible surface and the stability studies of the structure model of the Cry2Aa-BNS3-49 form showed a lower hydrophobicity surface due to the omission of 144 amino acids from the N-terminal comparing with the active Cry2Aa-MEB4 protein. All these features caused the diminishing of Cry2Aa-BNS3 toxicity towards E. kuehniella. PMID:26321422

  12. MAPK Cascades in Guard Cell Signal Transduction

    PubMed Central

    Lee, Yuree; Kim, Yun Ju; Kim, Myung-Hee; Kwak, June M.

    2016-01-01

    Guard cells form stomata on the epidermis and continuously respond to endogenous and environmental stimuli to fine-tune the gas exchange and transpirational water loss, processes which involve mitogen-activated protein kinase (MAPK) cascades. MAPKs form three-tiered kinase cascades with MAPK kinases and MAPK kinase kinases, by which signals are transduced to the target proteins. MAPK cascade genes are highly conserved in all eukaryotes, and they play crucial roles in myriad developmental and physiological processes. MAPK cascades function during biotic and abiotic stress responses by linking extracellular signals received by receptors to cytosolic events and gene expression. In this review, we highlight recent findings and insights into MAPK-mediated guard cell signaling, including the specificity of MAPK cascades and the remaining questions. PMID:26904052

  13. MAPK Cascades in Guard Cell Signal Transduction.

    PubMed

    Lee, Yuree; Kim, Yun Ju; Kim, Myung-Hee; Kwak, June M

    2016-01-01

    Guard cells form stomata on the epidermis and continuously respond to endogenous and environmental stimuli to fine-tune the gas exchange and transpirational water loss, processes which involve mitogen-activated protein kinase (MAPK) cascades. MAPKs form three-tiered kinase cascades with MAPK kinases and MAPK kinase kinases, by which signals are transduced to the target proteins. MAPK cascade genes are highly conserved in all eukaryotes, and they play crucial roles in myriad developmental and physiological processes. MAPK cascades function during biotic and abiotic stress responses by linking extracellular signals received by receptors to cytosolic events and gene expression. In this review, we highlight recent findings and insights into MAPK-mediated guard cell signaling, including the specificity of MAPK cascades and the remaining questions. PMID:26904052

  14. Stochastic annealing simulation of cascades in metals

    SciTech Connect

    Heinisch, H.L.

    1996-04-01

    The stochastic annealing simulation code ALSOME is used to investigate quantitatively the differential production of mobile vacancy and SIA defects as a function of temperature for isolated 25 KeV cascades in copper generated by MD simulations. The ALSOME code and cascade annealing simulations are described. The annealing simulations indicate that the above Stage V, where the cascade vacancy clusters are unstable,m nearly 80% of the post-quench vacancies escape the cascade volume, while about half of the post-quench SIAs remain in clusters. The results are sensitive to the relative fractions of SIAs that occur in small, highly mobile clusters and large stable clusters, respectively, which may be dependent on the cascade energy.

  15. AAS 228: Day 2 afternoon

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.The Limits of Scientific Cosmology: Setting the Stage: Accepted Facts, and Testing Limitations in Theory and Data (by Gourav Khullar)With a stellar lineup of speakers to talk about current and future prospects of cosmology and its limits (or lack thereof), the first session kicked off with talks by Risa Wechsler, Joseph Silk, and Sean Carroll (his talk on Multiverses is described below, by Nathan Sanders). Risa set the stage with an elaborate description of the current accepted facts in the era of precision cosmology including the standard model of concordance cosmology, described by seven parameters and an accepted Lambda-CDM paradigm (with a cosmological constant and cold dark matter). The talk stressed on the fact that all these parameters are understood to a percent order precision, which is a remarkable deviation from the time in 1990s when according to Risa, Alan Guth never thought that any of these numbers could be measured precisely!Risa Wechsler describing our current constraints on what Dark Matter could constitute.Joseph Silk discussing limits on cosmological parameters.The CMB measurements, Big Bang Nucleosynthesis estimates and galaxy clustering statistics all contribute to locking down the description of our universe. She emphasized on the tensions between different probes to measure expansion rate H0 of the universe, and small scale predictions of cold dark matter simulations, but she is hopeful that these shall be resolved eventually. Joe Silk followed this up with his interpretation of trying to understand our place in the universe and placing limits on different parameters and

  16. AAS 228: Day 2 morning

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Plenary Session (Day 1) The Galaxy Zoo(by Benny Tsang)Galaxy Zoo was so hot that the servers hosting the galaxy images got melted down soon after being launched.Kevin Schawinski from ETH Zurich took us on a tour ofhis wonderful Galaxy Zoo. It is a huge zoo with about a quarter million zookeepers, they are citizen astronomers who collaboratively classify galaxies by their looks as an attempt to understand galaxy evolution. The big question that is being answered is: how do blue, actively star-forming galaxies evolve into red, quiescent (non-star-forming) galaxies? The Zoo helped reveal that blue galaxies turn into red galaxies via two possible paths galaxies might run out of supply of gas and shut off star formation slowly; or they could merge with one another and turn off star formation by destroying the gas reservoir rapidly!The Galaxy Zoo project also led to the discoveries of:Green Peas: they are the living fossils of galaxy evolution; compact, bright, green galaxies that are actively forming starsOverlapping galaxies: they are pairs of galaxies that are separated physically but happen to lie on the same line of sight; they provide excellent laboratories for studying dust extinctionHannys Voorwerp: an unusual object named after Hanny the discoverer, which is believed to be the first detection of quasar light echoThe idea of Galaxy Zoo in getting help from citizen scientists was further extended into an award-winningproject known as the Zooniverse, which is an online platform for streamlined crowd-sourcing for scientific research that requires human input. The future of astronomy is going to be

  17. AAS 228: Day 2 afternoon

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.The Limits of Scientific Cosmology: Setting the Stage: Accepted Facts, and Testing Limitations in Theory and Data (by Gourav Khullar)With a stellar lineup of speakers to talk about current and future prospects of cosmology and its limits (or lack thereof), the first session kicked off with talks by Risa Wechsler, Joseph Silk, and Sean Carroll (his talk on Multiverses is described below, by Nathan Sanders). Risa set the stage with an elaborate description of the current accepted facts in the era of precision cosmology including the standard model of concordance cosmology, described by seven parameters and an accepted Lambda-CDM paradigm (with a cosmological constant and cold dark matter). The talk stressed on the fact that all these parameters are understood to a percent order precision, which is a remarkable deviation from the time in 1990s when according to Risa, Alan Guth never thought that any of these numbers could be measured precisely!Risa Wechsler describing our current constraints on what Dark Matter could constitute.Joseph Silk discussing limits on cosmological parameters.The CMB measurements, Big Bang Nucleosynthesis estimates and galaxy clustering statistics all contribute to locking down the description of our universe. She emphasized on the tensions between different probes to measure expansion rate H0 of the universe, and small scale predictions of cold dark matter simulations, but she is hopeful that these shall be resolved eventually. Joe Silk followed this up with his interpretation of trying to understand our place in the universe and placing limits on different parameters and

  18. Cascades in interdependent flow networks

    NASA Astrophysics Data System (ADS)

    Scala, Antonio; De Sanctis Lucentini, Pier Giorgio; Caldarelli, Guido; D'Agostino, Gregorio

    2016-06-01

    In this manuscript, we investigate the abrupt breakdown behavior of coupled distribution grids under load growth. This scenario mimics the ever-increasing customer demand and the foreseen introduction of energy hubs interconnecting the different energy vectors. We extend an analytical model of cascading behavior due to line overloads to the case of interdependent networks and find evidence of first order transitions due to the long-range nature of the flows. Our results indicate that the foreseen increase in the couplings between the grids has two competing effects: on the one hand, it increases the safety region where grids can operate without withstanding systemic failures; on the other hand, it increases the possibility of a joint systems' failure.

  19. The Geant4 Bertini Cascade

    NASA Astrophysics Data System (ADS)

    Wright, D. H.; Kelsey, M. H.

    2015-12-01

    One of the medium energy hadron-nucleus interaction models in the GEANT4 simulation toolkit is based partly on the Bertini intranuclear cascade model. Since its initial appearance in the toolkit, this model has been largely re-written in order to extend its physics capabilities and to reduce its memory footprint. Physics improvements include extensions in applicable energy range and incident particle types, and improved hadron-nucleon cross-sections and angular distributions. Interfaces have also been developed which allow the model to be coupled with other GEANT4 models at lower and higher energies. The inevitable speed reductions due to enhanced physics have been mitigated by memory and CPU efficiency improvements. Details of these improvements, along with selected comparisons of the model to data, are discussed.

  20. Diversity Cascades and Malaria Vectors

    PubMed Central

    CARLSON, JOHN C.; DYER, LEE A.; OMLIN, FRANCOIS X.; BEIER, JOHN C.

    2009-01-01

    The interactions between predator diversity and primary consumer abundance can include direct effects and indirect, cascading effects. Understanding these effects on immature Anopheles mosquitoes is important in sub-Saharan Africa, where most cases of malaria occur. Aquatic predators and immature mosquitoes were collected from shallow pools of varying age previously excavated by brickmakers in the western highlands of Kenya. Path analysis showed an indirect negative effect of habitat age on An. gambiae (Giles, 1902) mediated by effects on predator diversity. Disturbance resets habitats to an earlier successional stage, diminishing predator diversity and increasing An. gambiae populations. The increase in vector abundance as a result of reduced predator diversity highlights the public health value in conserving native insect diversity. PMID:19496413

  1. Weak Interactions and Instability Cascades.

    PubMed

    Kadoya, Taku; McCann, Kevin S

    2015-01-01

    Food web theory states that a weak interactor which is positioned in the food web such that it tends to deflect, or mute, energy away from a potentially oscillating consumer-resource interaction often enhances community persistence and stability. Here we examine how adding other weak interactions (predation/harvesting) on the stabilizing weak interactor alters the stability of food web using a set of well-established food web models/modules. We show that such "weak on weak" interaction chains drive an indirect dynamic cascade that can rapidly ignite a distant consumer-resource oscillator. Nonetheless, we also show that the "weak on weak" interactions are still more stable than the food web without them, and so weak interactions still generally act to stabilize food webs. Rather, these results are best interpreted to say that the degree of the stabilizing effect of a given important weak interaction can be severely compromised by other weak interactions (including weak harvesting). PMID:26219561

  2. The Geant4 Bertini Cascade

    SciTech Connect

    Wright, D. H.; Kelsey, M. H.

    2015-12-01

    One of the medium energy hadron–nucleus interaction models in the Geant4 simulation toolkit is based partly on the Bertini intranuclear cascade model. Since its initial appearance in the toolkit, this model has been largely re-written in order to extend its physics capabilities and to reduce its memory footprint. Physics improvements include extensions in applicable energy range and incident particle types, and improved hadron–nucleon cross-sections and angular distributions. Interfaces have also been developed which allow the model to be coupled with other Geant4 models at lower and higher energies. The inevitable speed reductions due to enhanced physics have been mitigated by memory and CPU efficiency improvements. Details of these improvements, along with selected comparisons of the model to data, are discussed.

  3. Compact Quantum Cascade Laser Transmitter

    SciTech Connect

    Anheier, Norman C.; Hatchell, Brian K.; Gervais, Kevin L.; Wojcik, Michael D.; Krishnaswami, Kannan; Bernacki, Bruce E.

    2009-04-01

    ): In this paper we present design considerations, thermal and optical modeling results, and device performance for a ruggedized, compact laser transmitter that utilizes a room temperature quantum cascade (QC) laser source. The QC laser transmitter is intended for portable mid-infrared (3-12 µm) spectroscopy applications, where the atmospheric transmission window is relatively free of water vapor interference and where the molecular rotational vibration absorption features can be used to detect and uniquely identify chemical compounds of interest. Initial QC laser-based sensor development efforts were constrained by the complications of cryogenic operation. However, improvements in both QC laser designs and fabrication processes have provided room-temperature devices that now enable significant miniaturization and integration potential for national security, environmental monitoring, atmospheric science, and industrial safety applications.

  4. Developmental nephrotoxicity of aristolochic acid in a zebrafish model

    SciTech Connect

    Ding, Yu-Ju; Chen, Yau-Hung

    2012-05-15

    Aristolochic acid (AA) is a component of Aristolochia plant extracts which is used as a treatment for different pathologies and their toxicological effects have not been sufficiently studied. The aim of this study was to evaluate AA-induced nephrotoxicity in zebrafish embryos. After soaking zebrafish embryos in AA, the embryos displayed malformed kidney phenotypes, such as curved, cystic pronephric tubes, pronephric ducts, and cases of atrophic glomeruli. The percentages of embryos with malformed kidney phenotypes increased as the exposure dosages of AA increased. Furthermore, AA-treated embryos exhibited significantly reduced glomerular filtration rates (GFRs) in comparison with mock-control littermates (mock-control: 100 ± 2.24% vs. 10 ppm AA treatment for 3–5 h: 71.48 ± 18.84% ∼ 39.41 ± 15.88%), indicating that AA treatment not only caused morphological kidney changes but also induced renal failure. In addition to kidney malformations, AA-treated zebrafish embryos also exhibited deformed hearts, swollen pericardiums, impaired blood circulation and the accumulation(s) of red blood cells. Whole-mount in situ hybridization studies using cmlc2 and wt1b as riboprobes indicated that the kidney is more sensitive than the heart to AA damage. Real-time PCR showed that AA can up-regulate the expression of proinflammatory genes like TNFα, cox2 and mpo. These results support the following conclusions: (1) AA-induced renal failure is mediated by inflammation, which causes circulation dysfunction followed by serious heart malformation; and (2) the kidney is more sensitive than the heart to AA injury. -- Highlights: ► Zebrafish were used to evaluate aristolochic acid (AA)-induced nephrotoxicity. ► AA-treated zebrafish embryos exhibited deformed heart as well as malformed kidney. ► Kidney is more sensitive to AA injury than the heart.

  5. The AAS: Its Next 100 Years

    NASA Astrophysics Data System (ADS)

    Wolff, S.

    1999-05-01

    The AAS: Its Next Hundred Years "We are probably nearing the limit of all we can know about astronomy."-- Simon Newcomb, 1888. The best way to celebrate the centennial of the AAS is to look forward, not backward, and to begin planning for the next 100 years. However, predicting the future is even more difficult than it was in Newcomb's time. We live in an era characterized by an unprecedented rate of change in the kinds of scientific questions we ask, the tools we use to answer them, and the way we communicate our results. This talk will highlight some of the issues that we will face as a community during the next 10--but not the next 100!--years and suggests that the AAS has a fundamental role to play in shaping the community response to these issues.

  6. Synthetic cascades are enabled by combining biocatalysts with artificial metalloenzymes

    NASA Astrophysics Data System (ADS)

    Köhler, V.; Wilson, Y. M.; Dürrenberger, M.; Ghislieri, D.; Churakova, E.; Quinto, T.; Knörr, L.; Häussinger, D.; Hollmann, F.; Turner, N. J.; Ward, T. R.

    2013-02-01

    Enzymatic catalysis and homogeneous catalysis offer complementary means to address synthetic challenges, both in chemistry and in biology. Despite its attractiveness, the implementation of concurrent cascade reactions that combine an organometallic catalyst with an enzyme has proven challenging because of the mutual inactivation of both catalysts. To address this, we show that incorporation of a d6-piano stool complex within a host protein affords an artificial transfer hydrogenase (ATHase) that is fully compatible with and complementary to natural enzymes, thus enabling efficient concurrent tandem catalysis. To illustrate the generality of the approach, the ATHase was combined with various NADH-, FAD- and haem-dependent enzymes, resulting in orthogonal redox cascades. Up to three enzymes were integrated in the cascade and combined with the ATHase with a view to achieving (i) a double stereoselective amine deracemization, (ii) a horseradish peroxidase-coupled readout of the transfer hydrogenase activity towards its genetic optimization, (iii) the formation of L-pipecolic acid from L-lysine and (iv) regeneration of NADH to promote a monooxygenase-catalysed oxyfunctionalization reaction.

  7. AAS 228: Day 2 morning

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Plenary Session (Day 1) The Galaxy Zoo(by Benny Tsang)Galaxy Zoo was so hot that the servers hosting the galaxy images got melted down soon after being launched.Kevin Schawinski from ETH Zurich took us on a tour ofhis wonderful Galaxy Zoo. It is a huge zoo with about a quarter million zookeepers, they are citizen astronomers who collaboratively classify galaxies by their looks as an attempt to understand galaxy evolution. The big question that is being answered is: how do blue, actively star-forming galaxies evolve into red, quiescent (non-star-forming) galaxies? The Zoo helped reveal that blue galaxies turn into red galaxies via two possible paths galaxies might run out of supply of gas and shut off star formation slowly; or they could merge with one another and turn off star formation by destroying the gas reservoir rapidly!The Galaxy Zoo project also led to the discoveries of:Green Peas: they are the living fossils of galaxy evolution; compact, bright, green galaxies that are actively forming starsOverlapping galaxies: they are pairs of galaxies that are separated physically but happen to lie on the same line of sight; they provide excellent laboratories for studying dust extinctionHannys Voorwerp: an unusual object named after Hanny the discoverer, which is believed to be the first detection of quasar light echoThe idea of Galaxy Zoo in getting help from citizen scientists was further extended into an award-winningproject known as the Zooniverse, which is an online platform for streamlined crowd-sourcing for scientific research that requires human input. The future of astronomy is going to be

  8. Effect of Insulin Sensitizer Therapy on Amino Acids and their Metabolites

    PubMed Central

    Irving, B.A.; Carter, R.E.; Soop, M.; Weymiller, A.; Syed, H.; Karakelides, H.; Bhagra, S.; Short, K.R.; Tatpati, L.; Barazzoni, R.; Nair, K.S.

    2015-01-01

    Aims Prior studies have reported that elevated concentrations of several plasma amino acids (AA) in plasma, particularly branched chain (BCAA) and aromatic AA predict the onset of type 2 diabetes. We sought to test the hypothesis that circulating BCAA, aromatic AA and related AA metabolites decline in response to the use of insulin sensitizing agents in overweight/obese adults with impaired fasting glucose or untreated diabetes. Methods We performed a secondary analysis of a randomized, double-blind, placebo, controlled study conducted in twenty five overweight/obese (BMI~30 kg/m2) adults with impaired fasting glucose or untreated diabetes. Participants were randomized to three months of pioglitazone (45 mg per day) plus metformin (1000 mg twice per day, N = 12 participants) or placebo (N = 13). We measured insulin sensitivity by the euglycemic-hyperinsulinemic clamp and fasting concentrations of AA and AA metabolites using ultra-pressure liquid chromatography tandem mass spectrometry before and after the three-month intervention. Results Insulin sensitizer therapy that significantly enhanced insulin sensitivity reduced 9 out of 33 AA and AA metabolites measured compared to placebo treatment. Moreover, insulin sensitizer therapy significantly reduced three functionally clustered AA and metabolite pairs: i) phenylalanine/tyrosine, ii) citrulline/arginine, and iii) lysine/α-aminoadipic acid. Conclusions Reductions in plasma concentrations of several AA and AA metabolites in response to three months of insulin sensitizer therapy support the concept that reduced insulin sensitivity alters AA and AA metabolites. PMID:25733201

  9. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., CERTIFICATION, AND STANDARDS) United States Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of stalks of celery of similar varietal characteristics, which are...

  10. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., CERTIFICATION, AND STANDARDS) United States Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of stalks of celery of similar varietal characteristics, which are...

  11. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of stalks of celery of similar varietal characteristics, which are well developed, and have good...

  12. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of stalks of celery of similar varietal characteristics, which are well developed, and have good...

  13. Cascade Biocatalysis for Sustainable Asymmetric Synthesis: From Biobased l-Phenylalanine to High-Value Chiral Chemicals.

    PubMed

    Zhou, Yi; Wu, Shuke; Li, Zhi

    2016-09-12

    Sustainable synthesis of useful and valuable chiral fine chemicals from renewable feedstocks is highly desirable but remains challenging. Reported herein is a designed and engineered set of unique non-natural biocatalytic cascades to achieve the asymmetric synthesis of chiral epoxide, diols, hydroxy acid, and amino acid in high yield and with excellent ee values from the easily available biobased l-phenylalanine. Each of the cascades was efficiently performed in one pot by using the cells of a single recombinant strain over-expressing 4-10 different enzymes. The cascade biocatalysis approach is promising for upgrading biobased bulk chemicals to high-value chiral chemicals. In addition, combining the non-natural enzyme cascades with the natural metabolic pathway of the host strain enabled the fermentative production of the chiral fine chemicals from glucose. PMID:27512928

  14. Cascade Screening in Familial Hypercholesterolemia: Advancing Forward.

    PubMed

    Santos, Raul D; Frauches, Thiago S; Chacra, Ana P M

    2015-01-01

    Familial hypercholesterolemia is a genetic disorder associated with elevated LDL-cholesterol and high lifetime cardiovascular risk. Both clinical and molecular cascade screening programs have been implemented to increase early definition and treatment. In this systematic review, we discuss the main issues found in 65 different articles related to cascade screening and familial hypercholesterolemia, covering a range of topics including different types/strategies, considerations both positive and negative regarding cascade screening in general and associated with the different strategies, cost and coverage consideration, direct and indirect contact with patients, public policy around life insurance and doctor-patient confidentiality, the "right to know," and public health concerns regarding familial hypercholesterolemia. PMID:26194978

  15. Gust Response Analysis of a Turbine Cascade

    NASA Technical Reports Server (NTRS)

    Gorla, R. S. R.; Reddy, T. S. R.; Reddy, D. R.; Kurkov, A. P.

    2001-01-01

    A study was made of the gust response of an annular turbine cascade using a two-dimensional Navier Stokes code. The time-marching CFD code, NPARC, was used to calculate the unsteady forces due to the fluid flow. The computational results were compared with a previously published experimental data for the annular cascade reported in the literature. Reduced frequency, Mach number and angle of incidence were varied independently and the gust velocity was sinusoidal. For the high inlet velocity case, the cascade was nearly choked.

  16. Cascades on clique-based graphs

    NASA Astrophysics Data System (ADS)

    Hackett, Adam; Gleeson, James P.

    2013-06-01

    We present an analytical approach to determining the expected cascade size in a broad range of dynamical models on the class of highly clustered random graphs introduced by Gleeson [J. P. Gleeson, Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.80.036107 80, 036107 (2009)]. A condition for the existence of global cascades is also derived. Applications of this approach include analyses of percolation, and Watts's model. We show how our techniques can be used to study the effects of in-group bias in cascades on social networks.

  17. Highly Diastereoselective Synthesis of Tetrahydropyridines by a C–H Activation–Cyclization–Reduction Cascade

    PubMed Central

    Duttwyler, Simon; Lu, Colin; Rheingold, Arnold L.

    2012-01-01

    A versatile reaction cascade leading to highly substituted 1,2,3,6-tetrahydropyridines has been developed. It comprises rhodium(I)-catalyzed C–H activation–alkyne coupling followed by electrocyclization and subsequent acid/borohydride-promoted reduction. This one pot procedure affords the target compounds in up to 95% yields and with >95% diastereomeric purity. PMID:22356093

  18. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. Grade AA. 51.596 Section 51.596 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of...

  19. A novel system combining biocatalytic dephosphorylation of L-ascorbic acid 2-phosphate and electrochemical oxidation of resulting ascorbic acid.

    PubMed

    Kuwahara, Takashi; Homma, Toshimasa; Kondo, Mizuki; Shimomura, Masato

    2011-03-15

    An enzyme electrode was prepared with acid phosphatase (ACP) for development of a new electric power generation system using ascorbic acid 2-phosphate (AA2P) as a fuel. The properties of the electrode were investigated with respect to biocatalytic dephosphorylation of AA2P and electrochemical oxidation of resulting ascorbic acid (AA). The enzyme electrode was fabricated by immobilization of ACP through amide linkage onto a self-assembled monolayer of 3-mercaptopropionic acid on a gold electrode. AA2P was not oxidized on a bare gold electrode in the potential sweep range from -0.1 to +0.5 V vs. Ag/AgCl. However, the enzyme electrode gave an oxidation current in citric buffer solution of pH 5 containing 10 mM of AA2P. The oxidation current began to increase at +0.2V, and reached to 5.0 μA cm(-2) at +0.5 V. The potential +0.2 V corresponded to the onset of oxidation of ascorbic acid (AA). These results suggest that the oxidation current observed with the enzyme electrode is due to AA resulting from dephosphorylation of AA2P. The oxidation current increased with increasing concentration of AA2P and almost leveled off at around the concentration of 5mM. Thus the enzyme electrode brought about biocatalytic conversion of AA2P to AA, followed by electrochemical oxidation of the AA. The oxidation current is likely to be controlled by the biocatalytic reaction. PMID:21247749

  20. Cascade-able spin torque logic gates with input-output isolation

    NASA Astrophysics Data System (ADS)

    Nikonov, Dmitri E.; Manipatruni, Sasikanth; Young, Ian A.

    2015-06-01

    Spin torque majority gate (STMG) is one of the promising options for beyond-complementary metal-oxide-semiconductor non-volatile logic circuits for normally-off computing. Modeling of prior schemes demonstrated logic completeness using majority operation and nonlinear transfer characteristics. However significant problems arose with cascade-ability and input output isolation manifesting as domain walls (DWs) stopping, reflecting off ends of wires or propagating back to the inputs. We introduce a new scheme to enable cascade-ability and isolation based on (a) in-plane DW automotion in interconnects, (b) exchange coupling of magnetization between two FM layers, and (c) ‘round-about’ topology for the majority gate. We performed micro-magnetic simulations that demonstrate switching operation of this STMG scheme. These circuits were verified to enable isolation of inputs from output signals and to be cascade-able without limitations.

  1. Mount Rainier active cascade volcano

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mount Rainier is one of about two dozen active or recently active volcanoes in the Cascade Range, an arc of volcanoes in the northwestern United States and Canada. The volcano is located about 35 kilometers southeast of the Seattle-Tacoma metropolitan area, which has a population of more than 2.5 million. This metropolitan area is the high technology industrial center of the Pacific Northwest and one of the commercial aircraft manufacturing centers of the United States. The rivers draining the volcano empty into Puget Sound, which has two major shipping ports, and into the Columbia River, a major shipping lane and home to approximately a million people in southwestern Washington and northwestern Oregon. Mount Rainier is an active volcano. It last erupted approximately 150 years ago, and numerous large floods and debris flows have been generated on its slopes during this century. More than 100,000 people live on the extensive mudflow deposits that have filled the rivers and valleys draining the volcano during the past 10,000 years. A major volcanic eruption or debris flow could kill thousands of residents and cripple the economy of the Pacific Northwest. Despite the potential for such danger, Mount Rainier has received little study. Most of the geologic work on Mount Rainier was done more than two decades ago. Fundamental topics such as the development, history, and stability of the volcano are poorly understood.

  2. Quantum Cascade Laser Frequency Combs

    NASA Astrophysics Data System (ADS)

    Faist, Jérôme; Villares, Gustavo; Scalari, Giacomo; Rösch, Markus; Bonzon, Christopher; Hugi, Andreas; Beck, Mattias

    2016-06-01

    It was recently demonstrated that broadband quantum cascade lasers can operate as frequency combs. As such, they operate under direct electrical pumping at both mid-infrared and THz frequencies, making them very attractive for dual-comb spectroscopy. Performance levels are continuously improving, with average powers over 100mW and frequency coverage of 100 cm-1 in the mid-infrared region. In the THz range, 10mW of average power and 600 GHz of frequency coverage are reported. As a result of the very short upper state lifetime of the gain medium, the mode proliferation in these sources arises from four-wave mixing rather than saturable absorption. As a result, their optical output is characterized by the tendency of small intensity modulation of the output power, and the relative phases of the modes to be similar to the ones of a frequency modulated laser. Recent results include the proof of comb operation down to a metrological level, the observation of a Schawlow-Townes broadened linewidth, as well as the first dual-comb spectroscopy measurements. The capability of the structure to integrate monothically nonlinear optical elements as well as to operate as a detector shows great promise for future chip integration of dual-comb systems.

  3. Systemic AA amyloidosis: epidemiology, diagnosis, and management

    PubMed Central

    Real de Asúa, Diego; Costa, Ramón; Galván, Jose María; Filigheddu, María Teresa; Trujillo, Davinia; Cadiñanos, Julen

    2014-01-01

    The term “amyloidosis” encompasses the heterogeneous group of diseases caused by the extracellular deposition of autologous fibrillar proteins. The global incidence of amyloidosis is estimated at five to nine cases per million patient-years. While amyloid light-chain (AL) amyloidosis is more frequent in developed countries, amyloid A (AA) amyloidosis is more common in some European regions and in developing countries. The spectrum of AA amyloidosis has changed in recent decades owing to: an increase in the median age at diagnosis; a percent increase in the frequency of primary AL amyloidosis with respect to the AA type; and a substantial change in the epidemiology of the underlying diseases. Diagnosis of amyloidosis is based on clinical organ involvement and histological evidence of amyloid deposits. Among the many tinctorial characteristics of amyloid deposits, avidity for Congo red and metachromatic birefringence under unidirectional polarized light remain the gold standard. Once the initial diagnosis has been made, the amyloid subtype must be identified and systemic organ involvement evaluated. In this sense, the 123I-labeled serum amyloid P component scintigraphy is a safe and noninvasive technique that has revolutionized the diagnosis and monitoring of treatment in systemic amyloidosis. It can successfully identify anatomical patterns of amyloid deposition throughout the body and enables not only an initial estimation of prognosis, but also the monitoring of the course of the disease and the response to treatment. Given the etiologic diversity of AA amyloidosis, common therapeutic strategies are scarce. All treatment options should be based upon a greater control of the underlying disease, adequate organ support, and treatment of symptoms. Nevertheless, novel therapeutic strategies targeting the formation of amyloid fibrils and amyloid deposition may generate new expectations for patients with AA amyloidosis. PMID:25378951

  4. Temporal Variation of Aristolochia chilensis Aristolochic Acids during Spring.

    PubMed

    Santander, Rocío; Urzúa, Alejandro; Olguín, Ángel; Sánchez, María

    2015-01-01

    In this communication, we report the springtime variation of the composition of aristolochic acids (AAs) in Aristolochia chilensis leaves and stems. The dominant AA in the leaves of all samples, which were collected between October and December, was AA-I (1), and its concentration varied between 212.6±3.8 and 145.6±1.2 mg/kg and decreased linearly. This decrease occurred in parallel with the increase in AA-Ia (5) concentration from 15.9±0.8 mg/kg at the beginning of October to 96.8±7.8 mg/kg in mid-December. Both acids are enzymatically related by methylation-demethylation reactions. Other AAs also showed important variations: AA-II (2) significantly increased in concentration, reaching a maximum in the first two weeks of November and subsequently decreasing in mid-December to approximately the October levels. The principal component in the AA mixture of the stems was also AA-I (1); similar to AA-II (2), its concentration increased beginning in October, peaked in the second week of November and subsequently decreased. The concentrations of AA-IIIa (6) and AA-IVa (7) in the leaves and stems varied throughout the study period, but no clear pattern was identified. Based on the variation of AAs in A. chilensis leaves and stems during the study period, the reduced contents of non-phenolic AAs and increased concentrations of phenolic AAs are likely associated with a decrease in this plant's toxicity during the spring. PMID:26580587

  5. Processing and Optimization of Dissimilar Friction Stir Welding of AA 2219 and AA 7039 Alloys

    NASA Astrophysics Data System (ADS)

    Venkateswarlu, D.; Nageswara rao, P.; Mahapatra, M. M.; Harsha, S. P.; Mandal, N. R.

    2015-12-01

    The present paper discusses the optimization of dissimilar friction stir welding of AA 2219 and AA 7039 alloys with respect to tool design issues including microstructural study of weld. The optimized ultimate tensile strength was ~280 MPa, and % elongation was ~11.5. It was observed that the extent of tool shoulder flat surface and tool rotational speed influenced the weld quality significantly. A mathematical model was also developed using response surface regression analysis to predict the effects of tool geometry and process variables on dissimilar AA 2219 and AA 7039 alloys welds. The microstructure evolution and mechanical properties were investigated by employing electron backscatter diffraction technique, Vickers microhardness, and tensile testing, respectively. The microstructural observations indicated that the grain size obtained at advancing side (AA 2219 alloy side) was much finer compared to the retreating side (AA 7039 alloy side). Hardness distribution in the stir zone was inhomogeneous, which might be due to inadequate mixing of weld zone material. The hardness values observed at the weld zone were lower than that in the base materials.

  6. HELIUM EFFECTS ON DISPLACEMENT CASCADE IN TUNGSTEN

    SciTech Connect

    Setyawan, Wahyu; Nandipati, Giridhar; Roche, Kenneth J.; Heinisch, Howard L.; Kurtz, Richard J.; Wirth, Brian D.

    2013-09-30

    Molecular dynamics (MD) simulations were performed to investigate He effects on displacement cascades in W. Helium content, proportion of interstitial and substitutional He and temperature were varied to reveal the various effects. The effect of interstitial He on the number of self-interstitial atoms (SIAs) produced during cascade damage appears to be insignificant. However, interstitial He tends to fill a vacancy (V). Nevertheless, this process is less favorable than SIA-V recombination particularly when excess SIAs are present before a cascade. The efficiency of He filling and SIA-V recombination increases as temperature increases due to increased point defect mobility. Likewise, substitutional He is more susceptible to displacement during a collision cascade than W. This susceptibility increases towards higher temperatures. Consequently, the number of surviving V is governed by the interplay between displaced substitutional He and SIA-V recombination. The temperature dependence of these processes results in a minimum number of V reached at an intermediate temperature.

  7. Displacement Cascade Damage Production in Metals

    SciTech Connect

    Stoller, Roger E; Malerba, Lorenzo; Nordlund, Kai

    2015-01-01

    Radiation-induced changes in microstructure and mechanical properties in structural materials are the result of a complex set of physical processes initiated by the collision between an energetic particle (neutron or ion) and an atom in the lattice. This primary damage event is called an atomic displacement cascade. The simplest description of a displacement cascade is to view it as a series of many billiard-ball-like elastic collisions among the atoms in the material. This chapter describes the formation and evolution of this primary radiation damage mechanism to provide an overview of how stable defects are formed by displacement cascades, as well as the nature and morphology of the defects themselves. The impact of the relevant variables such as cascade energy and irradiation temperature is discussed, and defect formation in different materials is compared.

  8. Signalling pathways: jack of all cascades.

    PubMed

    Cahill, M A; Janknecht, R; Nordheim, A

    1996-01-01

    The transcription factors that bind the c-fos promoter element SRE are targeted by multiple, independent signalling cascades; the identities of these signalling pathways and their modes of activation are being elucidated. PMID:8805215

  9. Modeling and analysis of cascade solar cells

    NASA Technical Reports Server (NTRS)

    Ho, F. D.

    1986-01-01

    A brief review is given of the present status of the development of cascade solar cells. It is known that photovoltaic efficiencies can be improved through this development. The designs and calculations of the multijunction cells, however, are quite complicated. The main goal is to find a method which is a compromise between accuracy and simplicity for modeling a cascade solar cell. Three approaches are presently under way, among them (1) equivalent circuit approach, (2) numerical approach, and (3) analytical approach. Here, the first and the second approaches are discussed. The equivalent circuit approach using SPICE (Simulation Program, Integrated Circuit Emphasis) to the cascade cells and the cascade-cell array is highlighted. The methods of extracting parameters for modeling are discussed.

  10. MAP kinase cascades: scaffolding signal specificity.

    PubMed

    van Drogen, Frank; Peter, Matthias

    2002-01-22

    Scaffold proteins organize many MAP kinase pathways by interacting with several components of these cascades. Recent studies suggest that scaffold proteins provide local activation platforms that contribute to signal specificity by insulating different MAP kinase pathways. PMID:11818078

  11. Cascade Error Projection: A New Learning Algorithm

    NASA Technical Reports Server (NTRS)

    Duong, T. A.; Stubberud, A. R.; Daud, T.; Thakoor, A. P.

    1995-01-01

    A new neural network architecture and a hardware implementable learning algorithm is proposed. The algorithm, called cascade error projection (CEP), handles lack of precision and circuit noise better than existing algorithms.

  12. Determining the direction of a turbulent cascade

    NASA Astrophysics Data System (ADS)

    Goldburg, Walter; Cerbus, Rory

    2015-11-01

    In two-dimensional (2D) turbulence, one expects a cascade of energy to larger spatial scales, while the enstrophy cascade is to smaller ones. Here we present a new tool to study cascades using simple ideas borrowed from information theory. It is entirely unrelated to the Navier-Stoke's equations or any scaling arguments. We use the conditional entropy (conditioned uncertainty) of velocity fluctuations on one scale conditioned on another larger or smaller scale. If the entropy is larger after conditioning on larger scales rather than smaller ones, then the cascade is to smaller scales. By varying the scale of the velocity fluctuations used in the conditioning, we can test both direction and locality. We use these tools on experimental data taken from a flowing soap film, an approximately 2D turbulent flow. The Reynolds number is varied over a wide range to determine the entropy's scaling with Reynolds number OIST.

  13. SAMPLING CHARGED PARTICLES WITH CASCADE IMPACTORS

    EPA Science Inventory

    The report discusses three sets of experiments which demonstrate that a cascade impactor sampling a charged aerosol may yield a particle size distribution measurement that deviates from the time distribution. The distributions indicated more large particles and fewer small partic...

  14. Network effects, cascades and CCP interoperability

    NASA Astrophysics Data System (ADS)

    Feng, Xiaobing; Hu, Haibo; Pritsker, Matthew

    2014-03-01

    To control counterparty risk, financial regulations such as the Dodd Frank Act are increasingly requiring standardized derivatives trades to be cleared by central counterparties (CCPs). It is anticipated that in the near-term future, CCPs across the world will be linked through interoperability agreements that facilitate risk-sharing but also serve as a conduit for transmitting shocks. This paper theoretically studies a network with CCPs that are linked through interoperability arrangements, and studies the properties of the network that contribute to cascading failures. The magnitude of the cascading is theoretically related to the strength of network linkages, the size of the network, the logistic mapping coefficient, a stochastic effect and CCP's defense lines. Simulations indicate that larger network effects increase systemic risk from cascading failures. The size of the network N raises the threshold value of shock sizes that are required to generate cascades. Hence, the larger the network, the more robust it will be.

  15. A DATA REDUCTION SYSTEM FOR CASCADE IMPACTORS

    EPA Science Inventory

    The report describes a computer-based data reduction system for cascade impactors. The system utilizes impactor-specific calibration information, together with operating conditions and other pertinent information (e.g., stage weights, sampling duration), to determine particle siz...

  16. Bacillus thuringiensis Crystal Protein Cry6Aa Triggers Caenorhabditis elegans Necrosis Pathway Mediated by Aspartic Protease (ASP-1)

    PubMed Central

    Zhang, Fengjuan; Peng, Donghai; Cheng, Chunsheng; Zhou, Wei; Ju, Shouyong; Wan, Danfeng; Yu, Ziquan; Shi, Jianwei; Deng, Yaoyao; Wang, Fenshan; Ye, Xiaobo; Hu, Zhenfei; Lin, Jian; Ruan, Lifang; Sun, Ming

    2016-01-01

    Cell death plays an important role in host-pathogen interactions. Crystal proteins (toxins) are essential components of Bacillus thuringiensis (Bt) biological pesticides because of their specific toxicity against insects and nematodes. However, the mode of action by which crystal toxins to induce cell death is not completely understood. Here we show that crystal toxin triggers cell death by necrosis signaling pathway using crystal toxin Cry6Aa-Caenorhabditis elegans toxin-host interaction system, which involves an increase in concentrations of cytoplasmic calcium, lysosomal lyses, uptake of propidium iodide, and burst of death fluorescence. We find that a deficiency in the necrosis pathway confers tolerance to Cry6Aa toxin. Intriguingly, the necrosis pathway is specifically triggered by Cry6Aa, not by Cry5Ba, whose amino acid sequence is different from that of Cry6Aa. Furthermore, Cry6Aa-induced necrosis pathway requires aspartic protease (ASP-1). In addition, ASP-1 protects Cry6Aa from over-degradation in C. elegans. This is the first demonstration that deficiency in necrosis pathway confers tolerance to Bt crystal protein, and that Cry6A triggers necrosis represents a newly added necrosis paradigm in the C. elegans. Understanding this model could lead to new strategies for nematode control. PMID:26795495

  17. Protection of free radical-induced cytotoxicity by 2-O-α-D-glucopyranosyl-L-ascorbic acid in human dermal fibroblasts.

    PubMed

    Hanada, Yukako; Iomori, Atsuko; Ishii, Rie; Gohda, Eiichi; Tai, Akihiro

    2014-01-01

    The stable ascorbic acid (AA) derivative, 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G), exhibits vitamin C activity after enzymatic hydrolysis to AA. The biological activity of AA-2G per se has not been studied in detail, although AA-2G has been noted as a stable source for AA supply. The protective effect of AA-2G against the oxidative cell death of human dermal fibroblasts induced by incubating with 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) for 24 h was investigated in this study. AA-2G showed a significant protective effect against the oxidative stress in a concentration-dependent manner. AA-2G did not exert a protective effect during the initial 12 h of incubation, but had a significant protective effect in the later part of the incubation period. Experiments using a α-glucosidase inhibitor and comparative experiments using a stereoisomer of AA-2G confirmed that AA-2G had a protective effect against AAPH-induced cytotoxicity without being converted to AA. Our results provide an insight into the efficacy of AA-2G as a biologically interesting antioxidant and suggest the practical use of AA-2G even before being converted into AA as a beneficial antioxidant. PMID:25036685

  18. Experimental determination of unsteady blade element aerodynamics in cascades. Volume 2: Translation mode cascade

    NASA Technical Reports Server (NTRS)

    Riffel, R. E.; Rothrock, M. D.

    1980-01-01

    A two dimensional cascade of harmonically oscillating airfoils was designed to model a near tip section from a rotor which was known to have experienced supersonic translational model flutter. This five bladed cascade had a solidity of 1.52 and a setting angle of 0.90 rad. Unique graphite epoxy airfoils were fabricated to achieve the realistic high reduced frequency level of 0.15. The cascade was tested over a range of static pressure ratios approximating the blade element operating conditions of the rotor along a constant speed line which penetrated the flutter boundary. The time steady and time unsteady flow field surrounding the center cascade airfoil were investigated.

  19. Comparative study of two chitin-active and two cellulose-active AA10-type lytic polysaccharide monooxygenases.

    PubMed

    Forsberg, Zarah; Røhr, Asmund Kjendseth; Mekasha, Sophanit; Andersson, K Kristoffer; Eijsink, Vincent G H; Vaaje-Kolstad, Gustav; Sørlie, Morten

    2014-03-18

    Lytic polysaccharide monooxygenases (LPMOs), found in family 9 (previously GH61), family 10 (previously CBM33), and the newly discovered family 11 of auxiliary activities (AA) in the carbohydrate-active enzyme classification system, are copper-dependent enzymes that oxidize sp(3)-carbons in recalcitrant polysaccharides such as chitin and cellulose in the presence of an external electron donor. In this study, we describe the activity of two AA10-type LPMOs whose activities have not been described before and we compare in total four different AA10-type LPMOs with the aim of finding possible correlations between their substrate specificities, sequences, and EPR signals. EPR spectra indicate that the electronic environment of the copper varies within the AA10 family even though amino acids directly interacting with the copper atom are identical in all four enzymes. This variation seems to be correlated to substrate specificity and is likely caused by sequence variation in areas that affect substrate binding geometry and/or by variation in a cluster of conserved aromatic residues likely involved in electron transfer. Interestingly, EPR signals for cellulose-active AA10 enzymes were similar to those previously observed for cellulose-active AA9 enzymes. Mutation of the conserved phenylalanine positioned in close proximity to the copper center in AA10-type LPMOs to Tyr (the corresponding residue in most AA9-type LPMOs) or Ala, led to complete or partial inactivation, respectively, while in both cases the ability to bind copper was maintained. Moreover, substrate binding affinity and degradation ability seemed hardly correlated, further emphasizing the crucial role of the active site configuration in determining LPMO functionality. PMID:24559135

  20. Distinct Plasma Profile of Polar Neutral Amino Acids, Leucine, and Glutamate in Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Tirouvanziam, Rabindra; Obukhanych, Tetyana V.; Laval, Julie; Aronov, Pavel A.; Libove, Robin; Banerjee, Arpita Goswami; Parker, Karen J.; O'Hara, Ruth; Herzenberg, Leonard A.; Herzenberg, Leonore A.; Hardan, Antonio Y.

    2012-01-01

    The goal of this investigation was to examine plasma amino acid (AA) levels in children with Autism Spectrum Disorders (ASD, N = 27) and neuro-typically developing controls (N = 20). We observed reduced plasma levels of most polar neutral AA and leucine in children with ASD. This AA profile conferred significant post hoc power for discriminating…

  1. Emergence of event cascades in inhomogeneous networks.

    PubMed

    Onaga, Tomokatsu; Shinomoto, Shigeru

    2016-01-01

    There is a commonality among contagious diseases, tweets, and neuronal firings that past events facilitate the future occurrence of events. The spread of events has been extensively studied such that the systems exhibit catastrophic chain reactions if the interaction represented by the ratio of reproduction exceeds unity; however, their subthreshold states are not fully understood. Here, we report that these systems are possessed by nonstationary cascades of event-occurrences already in the subthreshold regime. Event cascades can be harmful in some contexts, when the peak-demand causes vaccine shortages, heavy traffic on communication lines, but may be beneficial in other contexts, such that spontaneous activity in neural networks may be used to generate motion or store memory. Thus it is important to comprehend the mechanism by which such cascades appear, and consider controlling a system to tame or facilitate fluctuations in the event-occurrences. The critical interaction for the emergence of cascades depends greatly on the network structure in which individuals are connected. We demonstrate that we can predict whether cascades may emerge, given information about the interactions between individuals. Furthermore, we develop a method of reallocating connections among individuals so that event cascades may be either impeded or impelled in a network. PMID:27625183

  2. Forward and Inverse Cascades in EMHD Turbulence

    NASA Astrophysics Data System (ADS)

    Cho, Jungyeon

    2016-05-01

    Electron magnetohydrodynamics (EMHD) provides a simple fluid-like description of physics below the proton gyro-scale in collisionless plasmas, such as the solar wind. In this paper, we discuss forward and inverse cascades in EMHD turbulence in the presence of a strong mean magnetic field. Similar to Alfvén waves, EMHD waves, or EMHD perturbations, propagate along magnetic field lines. Therefore, two types of EMHD waves can exist: waves moving parallel to and waves moving anti-parallel to the the magnetic field lines. For energy cascade in EMHD turbulence, the relative amplitudes of opposite-traveling waves are important. When the amplitudes are balanced, we will see fully-developed forward cascade with a k -7/3 energy spectrum and a scale-dependent anisotropy. On the other hand, when the amplitudes are imbalanced, we will see inverse cascade, as well as (presumably not fully developed) forward cascade. The underlying physics for the inverse cascade is magnetic helicity conservation.

  3. Evaluation of AA5052 alloy anode in alkaline electrolyte with organic rare-earth complex additives for aluminium-air batteries

    NASA Astrophysics Data System (ADS)

    Wang, Dapeng; Li, Heshun; Liu, Jie; Zhang, Daquan; Gao, Lixin; Tong, Lin

    2015-10-01

    Behaviours of the AA5052 aluminium alloy anode of the alkaline aluminium-air battery are studied by the hydrogen evolution test, the electrochemical measurements and the surface analysis method. The combination of amino-acid and rare earth as electrolyte additives effectively retards the self-corrosion of AA5052 aluminium alloy in 4 M NaOH solution. It shows that the combination of L-cysteine and cerium nitrate has a synergistic effect owing to the formation of a complex film on AA5052 alloy surface. The organic rare-earth complex can decrease the anodic polarisation, suppress the hydrogen evolution and increase the anodic utilization rate.

  4. High Efficiency Cascade Solar Cells

    SciTech Connect

    Shuguang Deng, Seamus Curran, Igor Vasiliev

    2010-09-28

    This report summarizes the main work performed by New Mexico State University and University of Houston on a DOE sponsored project High Efficiency Cascade Solar Cells. The main tasks of this project include materials synthesis, characterization, theoretical calculations, organic solar cell device fabrication and test. The objective of this project is to develop organic nano-electronic-based photovoltaics. Carbon nanotubes and organic conjugated polymers were used to synthesize nanocomposites as the new active semiconductor materials that were used for fabricating two device architectures: thin film coating and cascade solar cell fiber. Chemical vapor deposition technique was employed to synthesized a variety of carbon nanotubes (single-walled CNT, doubled-walled CNT, multi-walled CNT, N-doped SWCNT, DWCNT and MWCNT, and B-doped SWCNT, DWCNT and MWCNT) and a few novel carbon structures (CNT-based nanolance, nanocross and supported graphene film) that have potential applications in organic solar cells. Purification procedures were developed for removing amorphous carbons from carbon nanotubes, and a controlled oxidation method was established for partial truncation of fullerene molecules. Carbon nanotubes (DWCNT and DWCNT) were functionalized with fullerenes and dyes covalently and used to form nanocomposites with conjugated polymers. Biologically synthesized Tellurium nanotubes were used to form composite with the conjugated polymers as well, which generated the highest reported optical limiting values from composites. Several materials characterization technique including SEM/TEM, Raman, AFM, UV-vis, adsorption and EDS were employed to characterize the physical and chemical properties of the carbon nanotubes, the functionalized carbon nanotubes and the nanocomposites synthesized in this project. These techniques allowed us to have a spectroscopic and morphological control of the composite formation and to understand the materials assembled. A parallel 136-CPU

  5. Autonomous molecular cascades for evaluation of cell surfaces.

    PubMed

    Rudchenko, Maria; Taylor, Steven; Pallavi, Payal; Dechkovskaia, Alesia; Khan, Safana; Butler, Vincent P; Rudchenko, Sergei; Stojanovic, Milan N

    2013-08-01

    Molecular automata are mixtures of molecules that undergo precisely defined structural changes in response to sequential interactions with inputs. Previously studied nucleic acid-based automata include game-playing molecular devices (MAYA automata) and finite-state automata for the analysis of nucleic acids, with the latter inspiring circuits for the analysis of RNA species inside cells. Here, we describe automata based on strand-displacement cascades directed by antibodies that can analyse cells by using their surface markers as inputs. The final output of a molecular automaton that successfully completes its analysis is the presence of a unique molecular tag on the cell surface of a specific subpopulation of lymphocytes within human blood cells. PMID:23892986

  6. Duality cascade in brane inflation

    SciTech Connect

    Bean, Rachel; Chen Xingang; Hailu, Girma; Henry Tye, S-H; Xu Jiajun E-mail: xgchen@mit.edu E-mail: tye@lepp.cornell.edu

    2008-03-15

    We show that brane inflation is very sensitive to tiny sharp features in extra dimensions, including those in the potential and in the warp factor. This can show up as observational signatures in the power spectrum and/or non-Gaussianities of the cosmic microwave background radiation (CMBR). One general example of such sharp features is a succession of small steps in a warped throat, caused by Seiberg duality cascade using gauge/gravity duality. We study the cosmological observational consequences of these steps in brane inflation. Since the steps come in a series, the prediction of other steps and their properties can be tested by future data and analysis. It is also possible that the steps are too close to be resolved in the power spectrum, in which case they may show up only in the non-Gaussianity of the CMB temperature fluctuations and/or EE polarization. We study two cases. In the slow-roll scenario, where steps appear in the inflaton potential, the sensitivity of brane inflation to the height and width of the steps is increased by several orders of magnitude compared to that in previously studied large field models. In the IR DBI scenario, where steps appear in the warp factor, we find that the glitches in the power spectrum caused by these sharp features are generally small or even unobservable, but associated distinctive non-Gaussianity can be large. Together with its large negative running of the power spectrum index, this scenario clearly illustrates how rich and different a brane inflationary scenario can be when compared to generic slow-roll inflation. Such distinctive stringy features may provide a powerful probe of superstring theory.

  7. Expression of cationic amino acid transporters, carcass traits, and performance of growing pigs fed low-protein amino acid-supplemented versus high protein diets.

    PubMed

    Morales, A; Grageola, F; García, H; Araiza, A; Zijlstra, R T; Cervantes, M

    2013-01-01

    Free amino acids (AA) appear to be absorbed faster than protein-bound AA (PB-AA). We conducted an experiment to assess the effect of feeding pigs with a partially free (F-AA) or totally PB-AA diet on expression of selected genes and performance of pigs. The expression of cationic AA transporters b(0,+) and CAT-1 in intestinal mucosa, liver, and longissimus (LM) and semitendinosus (SM) muscles, as well as that of myosin in LM and SM, was analyzed. Twelve pigs (31.7 ± 2.7 kg) were used. The F-AA diet was based on wheat, supplemented with 0.59% L-Lys, 0.33% L-Thr, and 0.10% DL-Met. The PB-AA diet was formulated with wheat-soybean meal. Average daily feed intake was 1.53 kg per pig. The expression of b(0,+) and CAT-1 was analyzed in jejunal and ileal mucosa, liver, LM, and SM; myosin expression was also analyzed in both muscles. Pigs fed the PB-AA diet tended to have higher weight gain and feed efficiency (P < 0.10), and had thinner back fat (P = 0.02). The expression of b(0,+) was higher (P < 0.01) in jejunum but lower (P < 0.01) in the liver of pigs fed the F-AA diet; CAT-1 tended to be lower in liver but higher in LM of PB-AA pigs. Myosin expression was not affected. Intestinal AA absorption was faster in pigs fed the F-AA diet, but AA uptake by the liver seemed to be faster in pigs fed the PB-AA. Performance and expression of AA transporters and myosin suggest that the dietary content of free or protein-bound AA does not affect their availability for protein synthesis in pigs. PMID:24222247

  8. An equation to estimate the difference between theoretically predicted and SDS PAGE-displayed molecular weights for an acidic peptide.

    PubMed

    Guan, Yihong; Zhu, Qinfang; Huang, Delai; Zhao, Shuyi; Jan Lo, Li; Peng, Jinrong

    2015-01-01

    The molecular weight (MW) of a protein can be predicted based on its amino acids (AA) composition. However, in many cases a non-chemically modified protein shows an SDS PAGE-displayed MW larger than its predicted size. Some reports linked this fact to high content of acidic AA in the protein. However, the exact relationship between the acidic AA composition and the SDS PAGE-displayed MW is not established. Zebrafish nucleolar protein Def is composed of 753 AA and shows an SDS PAGE-displayed MW approximately 13 kDa larger than its predicted MW. The first 188 AA in Def is defined by a glutamate-rich region containing ~35.6% of acidic AA. In this report, we analyzed the relationship between the SDS PAGE-displayed MW of thirteen peptides derived from Def and the AA composition in each peptide. We found that the difference between the predicted and SDS PAGE-displayed MW showed a linear correlation with the percentage of acidic AA that fits the equation y = 276.5x - 31.33 (x represents the percentage of acidic AA, 11.4% ≤ x ≤ 51.1%; y represents the average ΔMW per AA). We demonstrated that this equation could be applied to predict the SDS PAGE-displayed MW for thirteen different natural acidic proteins. PMID:26311515

  9. Colchicine use in isolated renal AA amyloidosis.

    PubMed

    Meneses, Carlos F; Egües, César A; Uriarte, Miren; Belzunegui, Joaquín; Rezola, Marta

    2015-01-01

    We present the case of a 45-year-old woman, with two-year history of chronic renal insufficiency and proteinuria. A kidney biopsy showed the presence of AA amyloidosis (positive Congo red staining and immunohistochemistry). There was no evidence of amyloid deposits in other organs and there was no underlying disease. AA amyloidosis normally is secondary to chronic inflammatory or infectious diseases. High levels of IL-1, IL-6 and TNF-α play a role in the pathogenesis of amyloidosis and induce the synthesis of serum amyloid A protein (SAA), a precursor of tissue amyloid deposits. We empirically treated the patient with a low dose colchicine. The patient responded well. Colchicine has been used for the treatment of Familiar Mediterranean Fever and related auto-inflammatory diseases. To monitor treatment responses, we measured SAA finding low titers. Soon after treatment onset there were signs of improvement pertaining to proteinuria and stabilization of renal function. PMID:25453598

  10. The Effectiveness of the AAS REU Program

    NASA Astrophysics Data System (ADS)

    Hemenway, M. K.; Boyce, P. B.; Milkey, R. W.

    1996-05-01

    In an attempt to address the particular needs of astronomy faculty and undergraduate students, in 1991 the Education Office of the American Astronomical Society approached the National Science Foundation with a unique proposal for funding through the Research Experiences for Undergraduates program. The goals of the AAS program were to "slow the hemorrhage of students out of science...", extend the REU program to non-NSF-funded scientists, to reach under-represented women and minority students particularly in small educational institutions, and to encourage research scientists there to mentor students. As this grant has now expired, the AAS has surveyed the 44 mentors and their students to assess the program's effect on the mentor and the mentor's career; the educational institution; and the student's education and career choices. More than half the mentors responded by the abstract deadline. The program clearly had an effect upon the individuals involved. The greatest effect (in 85% of the cases) was to develop more interest in the mentor's research project both among the students and among the mentor's faculty colleagues. The mentors rated the grant to be a medium or strong factor in their student's decision to pursue graduate study, which 90% of them did. All but one of the AAS-REU students attended an AAS meeting and 3/4 of those gave a paper on their project research. Over 90% of the mentors felt that the research experience strongly promoted a greater interest in science, a greater understanding of science and a desire to continue in science. According to the mentors, this was a very positive and beneficial program for the students as well as for themselves.

  11. Metal-Catalyzed Double Migratory Cascade Reactions of Propargylic Esters and Phosphates

    PubMed Central

    Shiroodi, Roohollah Kazem

    2013-01-01

    Propargylic esters and phosphates are easily accessible substrates, which exhibit rich and tunable reactivities in the presence of transition metal catalysts. π-acidic metals, mostly gold and platinum salts, activate these substrates for an initial 1,2- or 1,3-acyloxy and phosphatyloxy migration processes to form reactive intermediates. These intermediates are able to undergo further cascade reactions leading to a variety of diverse structures. This tutorial review systematically introduces the double migratory reactions of propargylic esters and phosphates as a novel synthetic method, in which further cascade reaction of the reactive intermediate is accompanied by a second migration of a different group, thus offering a rapid route to a wide range of functionalized products. The serendipitous observations, as well as designed approaches involving the double migratory cascade reactions, will be discussed with emphasis placed on the mechanistic aspects and the synthetic utilities of the obtained products. PMID:23443274

  12. AAS Publishing News: Astronomical Software Citation Workshop

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-07-01

    Do you write code for your research? Use astronomical software? Do you wish there were a better way of citing, sharing, archiving, or discovering software for astronomy research? You're not alone! In April 2015, AAS's publishing team joined other leaders in the astronomical software community in a meeting funded by the Sloan Foundation, with the purpose of discussing these issues and potential solutions. In attendance were representatives from academic astronomy, publishing, libraries, for-profit software sharing platforms, telescope facilities, and grantmaking institutions. The goal of the group was to establish “protocols, policies, and platforms for astronomical software citation, sharing, and archiving,” in the hopes of encouraging a set of normalized standards across the field. The AAS is now collaborating with leaders at GitHub to write grant proposals for a project to develop strategies for software discoverability and citation, in astronomy and beyond. If this topic interests you, you can find more details in this document released by the group after the meeting: http://astronomy-software-index.github.io/2015-workshop/ The group hopes to move this project forward with input and support from the broader community. Please share the above document, discuss it on social media using the hashtag #astroware (so that your conversations can be found!), or send private comments to julie.steffen@aas.org.

  13. Introducing the AAS Astronomy Ambassadors Program

    NASA Astrophysics Data System (ADS)

    Gurton, S.; Fienberg, R. T.; Fraknoi, A.; Prather, E. E.

    2013-04-01

    Newly established by the American Astronomical Society (AAS), the Astronomy Ambassadors program is designed to support early-career AAS members with training in resources and techniques for effective outreach to students and/or the public. A pilot Astronomy Ambassadors workshop will be held at the January 2013 AAS meeting. Workshop participants will learn to communicate effectively with public and school audiences; find outreach opportunities and establish ongoing partnerships with local schools, science centers, museums, parks, and/or community centers; reach audiences with personal stories, hands-on activities, and jargon-free language; identify strategies and techniques to improve their presentation skills; gain access to a menu of outreach resources that work in a variety of settings; and become part of an active community of astronomers who do outreach. Applications are welcome from advanced undergraduates (those doing research and committed to continuing in astronomy), graduate students, and postdocs and new faculty in their first two years after receipt of the PhD. We especially encourage applications from members of groups that are presently underrepresented in science.

  14. Amino acid composition, including key derivatives of eccrine sweat: potential biomarkers of certain atopic skin conditions.

    PubMed

    Mark, Harker; Harding, Clive R

    2013-04-01

    The free amino acid (AA) composition of eccrine sweat is different from other biological fluids, for reasons which are not properly understood. We undertook the detailed analysis of the AA composition of freshly isolated pure human eccrine sweat, including some of the key derivatives of AA metabolism, to better understand the key biological mechanisms governing its composition. Eccrine sweat was collected from the axillae of 12 healthy subjects immediately upon formation. Free AA analysis was performed using an automatic AA analyser after ninhydrin derivatization. Pyrrolidine-5-carboxylic acid (PCA) and urocanic acid (UCA) levels were determined using GC/MS. The free AA composition of sweat was dominated by the presence of serine accounting for just over one-fifth of the total free AA composition. Glycine was the next most abundant followed by PCA, alanine, citrulline and threonine, respectively. The data obtained indicate that the AA content of sweat bears a remarkable similarity to the AA composition of the epidermal protein profilaggrin. This protein is the key source of free AAs and their derivatives that form a major part of the natural moisturizing factor (NMF) within the stratum corneum (SC) and plays a major role in maintaining the barrier integrity of human skin. As perturbations in the production of NMF can lead to abnormal barrier function and can arise as a consequence of filaggrin genotype, we propose the quantification of AAs in sweat may serve as a non-invasive diagnostic biomarker for certain atopic skin conditions, that is, atopic dermatitis (AD). PMID:23075272

  15. Oocyte-Specific Expression of Mouse MEX3C652AA in the Ovary and Its Potential Role in Regulating Maternal Fos mRNA.

    PubMed

    Li, Xue; Li, Yan; Liu, Chunlian; Jin, Mulan; Lu, Baisong

    2016-05-01

    Currently, the human MEX3C gene is known to encode an RNA-binding protein of 659 amino acid residues. Here we show that the MEX3C gene has alternative splicing forms giving rise to multiple MEX3C variants, and some cells express MEX3C transcripts coding for short MEX3C isoforms but not transcripts for MEX3C(659AA) MEX3C(659AA) functions as an adaptor protein for Exportin 1 (XPO1)-mediated nuclear export since it increases the cytoplasmic distribution of poly(A)(+) RNA and since addition of the nuclear export signal (NES) sequence to a short MEX3C isoform MEX3C(464AA) confers similar cytoplasmic poly(A)(+) RNA accumulation activity as MEX3C(659AA) FOS mRNA is a potential MEX3C target mRNA. One mechanism by which MEX3C(659AA) could regulate FOS mRNA is by promoting its nuclear export. Overexpressing MEX3C(659AA) significantly increased FOS mRNA expression, whereas mutating the NES of MEX3C(659AA) and treating cells with leptomycin B to inhibit XPO1-mediated nuclear export attenuated FOS upregulation. FOS mRNA is unstable in somatic cells but less so in oocytes; how it is stabilized in the oocytes is unknown. Transcripts for the mouse counterpart of human MEX3C(659AA) (MEX3C(652AA)) are specifically expressed in developing oocytes in the ovary, although total Mex3c transcripts are expressed in both granulosa cells and oocytes. The specific expression of this long MEX3C isoform in oocytes and its ability to enhance FOS mRNA nuclear export and stability all suggest that MEX3C(659AA) is an RNA-binding protein that preserves maternal FOS mRNA in oocytes. PMID:27053362

  16. High cycle fatigue of AA6082 and AA6063 aluminum extrusions

    NASA Astrophysics Data System (ADS)

    Nanninga, Nicholas E.

    The high cycle fatigue behavior of hollow extruded AA6082 and AA6063 aluminum extrusions has been studied. Hollow extruded aluminum profiles can be processed into intricate shapes, and may be suitable replacements for fatigue critical automotive applications requiring reduced weight. There are several features inherent in hollow aluminum extrusions, such as seam welds, charge welds, microstructural variations and die lines. The effects of such extrusion variables on high cycle fatigue properties were studied by taking specimens from an actual car bumper extrusion. It appears that extrusion die lines create large anisotropy differences in fatigue properties, while welds themselves have little effect on fatigue lives. Removal of die lines greatly increased fatigue properties of AA6082 specimens taken transverse to the extrusion direction. Without die lines, anisotropy in fatigue properties between AA6082 specimens taken longitudinal and transverse to the extrusion direction, was significantly reduced, and properties associated with the orientation of the microstructure appears to be isotropic. A fibrous microstructure for AA6082 specimens showed great improvements in fatigue behavior. The effects of elevated temperatures and exposure of specimens to NaCl solutions was also studied. Exposure to the salt solution greatly reduced the fatigue lives of specimens, while elevated temperatures showed more moderate reductions in fatigue lives.

  17. On the edge of an inverse cascade.

    PubMed

    Seshasayanan, Kannabiran; Benavides, Santiago Jose; Alexakis, Alexandros

    2014-11-01

    We demonstrate that systems with a parameter-controlled inverse cascade can exhibit critical behavior for which at the critical value of the control parameter the inverse cascade stops. In the vicinity of such a critical point, standard phenomenological estimates for the energy balance will fail since the energy flux towards large length scales becomes zero. We demonstrate this using the computationally tractable model of two-dimensional (2D) magnetohydrodynamics in a periodic box. In the absence of any external magnetic forcing, the system reduces to hydrodynamic fluid turbulence with an inverse energy cascade. In the presence of strong magnetic forcing, the system behaves as 2D magnetohydrodynamic turbulence with forward energy cascade. As the amplitude of the magnetic forcing is varied, a critical value is met for which the energy flux towards the large scales becomes zero. Close to this point, the energy flux scales as a power law with the departure from the critical point and the normalized amplitude of the fluctuations diverges. Similar behavior is observed for the flux of the square vector potential for which no inverse flux is observed for weak magnetic forcing, while a finite inverse flux is observed for magnetic forcing above the critical point. We conjecture that this behavior is generic for systems of variable inverse cascade. PMID:25493730

  18. The boundary layer on compressor cascade blades

    NASA Technical Reports Server (NTRS)

    Deutsch, S.; Zierke, W. C.

    1986-01-01

    The purpose of NASA Research Grant NSG-3264 is to characterize the flowfield about an airfoil in a cascade at chord Reynolds number(R sub C)near 5 x 10 to the 5th power. The program is experimental and combines laser Doppler velocimeter (LDV) measurements with flow visualization techniques in order to obtain detailed flow data, e.g., boundary layer profiles, points of separation and the transition zone, on a cascade of highly-loaded compressor blades. The information provided by this study is to serve as benchmark data for the evaluation of current and future compressor cascade predictive models, in this way aiding in the compressor design process. Summarized is the research activity for the period 1 December 1985 through 1 June 1986. Progress made from 1 June 1979 through 1 December 1985 is presented. Detailed measurements have been completed at the initial cascade angle of 53 deg. (incidence angle 5 degrees). A three part study, based on that data, has been accepted as part of the 1986 Gas Turbine Conference and will be submitted for subsequent journal publication. Also presented are data for a second cascade angle of 45 deg (an incidence angle of 3 degrees).

  19. Stability of Helium Clusters during Displacement Cascades

    SciTech Connect

    Yang, Li; Zu, Xiaotao T.; Xiao, H. Y.; Gao, Fei; Heinisch, Howard L.; Kurtz, Richard J.; Wang, Zhiguo; Liu, K. Z.

    2007-02-01

    The interaction of displacement cascades with helium-vacancy clusters is investigated using molecular dynamics simulations. The He-vacancy clusters initially consist of 20 vacancies with a Helium-to-vacancy ratio ranging from 0.2 to 3. The primary knock-on atom (PKA) energy, Ep, varies from 2 keV to 10 keV, and the PKA direction is chosen such that a displacement cascade is able to directly interact with a helium-vacancy cluster. The simulation results show that the effect of displacement cascades on a helium-vacancy cluster strongly depends on both the helium-to-vacancy ratio and the PKA energy. For the same PKA energy, the size of helium-vacancy clusters increases with the He/V ratio, but for the same ratio, the cluster size changes more significantly with increasing PKA energy. It has been observed that the He-vacancy clusters can be dissolved when the He/V ratio less than 1, but they are able to re-nucleate during the thermal spike phase, forming small He-V nuclei. When the He/V ratio is larger than 1, the He-V clusters can absorb a number of vacancies produced by displacement cascades, forming larger He-V clusters. These results are discussed in terms of PKA energy, helium-to-vacancy ratio, number of vacancies produced by cascades, and mobility of helium atoms.

  20. Harmonic cascade FEL designs for LUX

    SciTech Connect

    Penn, G.; Reinsch, M.; Wurtele, J.; Corlett, J.N.; Fawley, W.M.; Zholents, A.; Wan, W.

    2004-07-16

    LUX is a design concept for an ultrafast X-ray science facility, based on an electron beam accelerated to GeV energies in are circulating linac. Included in the design are short duration (200 fs or shorter FWHM) light sources using multiple stages of higher harmonic generation, seeded by a 200-250 nm laser of similar duration. This laser modulates the energy of a group of electrons within the electron bunch; this section of the electron bunch then produces radiation at a higher harmonic after entering a second, differently tuned undulator. Repeated stages in a cascade yield increasing photon energies up to 1 keV. Most of the undulators in the cascade operate in the low-gain FEL regime. Harmonic cascades have been designed for each pass of the recirculating linac up to a final electron beam energy of 3.1 GeV. For a given cascade, the photon energy can be selected over a wide range by varying the seed laser frequency and the field strength in the undulators. We present simulation results using the codes GENESIS and GINGER, as well as the results of analytical models which predict FEL performance. We discuss lattice considerations pertinent for harmonic cascade FELs, as well as sensitivity studies and requirements on the electron beam.

  1. The AAS Visiting Professor Programs: Three Anniversaries

    NASA Astrophysics Data System (ADS)

    Philip, A. G. Davis

    2003-05-01

    The AAS Program of Visiting Professors was started in 1958 with three astronomers as lecturers. They were Paul Merrill (Mt. Wilson and Palomar Observatories), Seth Nicholson (Mt. Wilson and Palomar Observatories) and Harlow Shapley (Harvard College Observatory). The program was run by a Committee on Visiting Professors from 1958 through 1963. The program was funded by grants from the National Science Foundation. The Executive Officer of the AAS, Paul Routley headed the program from the 1963 - 64 academic year through the 1968 - 69 academic year. Larry Fredrick headed the program for 1969 - 70 and then Hank Gurin headed it through 1973 -74, the last year of the program. At the end of this summer meeting, the combined Visiting Professors Program and the Shapley Program will be starting their 47th year. The Shapley Visiting Lectureships in Astronomy Program was started in the 1974 - 75 academic year under the leadership of Hank Gurin. The original funding came from the Perkin Fund and a three year grant from the Research Corporation. In 1975 the Shapley Endowment fund was set up to help pay the expenses of the program. In 1976 there was support from the Slipher fund which lasted through the 1978 - 79 academic year. From 1979 to the present the program is financed by the Shapley Endowment Fund and by the contributions made by institutions which host the visits. In the fall of 1998 the fee that Institutions pay to the AAS in support of their Shapley visits was reduced from 300 to 250 to make it easier for them to apply for visits. Members of the AAS have made contributions to the program over the years and we are very appreciative of this support. In 1974 there were 42 lecturers in the program, of whom four are still active giving lectures (George Carruthers, Larry Fredrick, Arlo Landolt and Davis Philip). After the summer meeting, the Shapley Program will be embarking on its 30th year. Now there are 82 astronomers in the program and we get from 40 to 60 requests a year

  2. ASCORBID ACID IS DECREASED IN INDUCED SPUTUM OF MILD ASTHMATICS

    EPA Science Inventory

    ABSTRACT
    Evidence suggests that the antioxidant ascorbic acid (AA), plays an essential role in defending against oxidant attack in the airways. Decreased levels of AA have been reported in asthmatics but not at the site directly proximal to asthma pathology, i.e. the bronchial...

  3. Cascaded Microinverter PV System for Reduced Cost

    SciTech Connect

    Bellus, Daniel R.; Ely, Jeffrey A.

    2013-04-29

    In this project, a team led by Delphi will develop and demonstrate a novel cascaded photovoltaic (PV) inverter architecture using advanced components. This approach will reduce the cost and improve the performance of medium and large-sized PV systems. The overall project objective is to develop, build, and test a modular 11-level cascaded three-phase inverter building block for photovoltaic applications and to develop and analyze the associated commercialization plan. The system will be designed to utilize photovoltaic panels and will supply power to the electric grid at 208 VAC, 60 Hz 3-phase. With the proposed topology, three inverters, each with an embedded controller, will monitor and control each of the cascade sections, reducing costs associated with extra control boards. This report details the final disposition on this project.

  4. Optical filtering enabled by cascaded parametric amplification.

    PubMed

    McKinstrie, C J; Dailey, J M; Agarwal, A; Toliver, P

    2016-06-27

    A cascaded parametric amplifier consists of a first parametric amplifier, which amplifies an input signal and generates an idler, which is a copy of the signal, a signal processor, which controls the phases of the signal and idler, and a second parametric amplifier, which combines the signal and idler in a phase-sensitive manner. In this paper, cascaded parametric amplification is modeled and the conditions required to maximize the constructive-destructive extinction ratio are determined. The results show that a cascaded parametric amplifier can be operated as a filter: A desired signal-idler pair is amplified, whereas undesired signal-idler pairs are deamplified. For the desired signal and idler, the noise figures of the filtering process (input signal-to-noise ratio divided by the output ratios) are only slightly higher than those of the copying process: Signal-processing functionality can be achieved with only a minor degradation in signal quality. PMID:27410581

  5. Bifurcations analysis of turbulent energy cascade

    SciTech Connect

    Divitiis, Nicola de

    2015-03-15

    This note studies the mechanism of turbulent energy cascade through an opportune bifurcations analysis of the Navier–Stokes equations, and furnishes explanations on the more significant characteristics of the turbulence. A statistical bifurcations property of the Navier–Stokes equations in fully developed turbulence is proposed, and a spatial representation of the bifurcations is presented, which is based on a proper definition of the fixed points of the velocity field. The analysis first shows that the local deformation can be much more rapid than the fluid state variables, then explains the mechanism of energy cascade through the aforementioned property of the bifurcations, and gives reasonable argumentation of the fact that the bifurcations cascade can be expressed in terms of length scales. Furthermore, the study analyzes the characteristic length scales at the transition through global properties of the bifurcations, and estimates the order of magnitude of the critical Taylor-scale Reynolds number and the number of bifurcations at the onset of turbulence.

  6. Cascade enzymatic reactions for efficient carbon sequestration.

    PubMed

    Xia, Shunxiang; Zhao, Xueyan; Frigo-Vaz, Benjamin; Zheng, Wenyun; Kim, Jungbae; Wang, Ping

    2015-04-01

    Thermochemical processes developed for carbon capture and storage (CCS) offer high carbon capture capacities, but are generally hampered by low energy efficiency. Reversible cascade enzyme reactions are examined in this work for energy-efficient carbon sequestration. By integrating the reactions of two key enzymes of RTCA cycle, isocitrate dehydrogenase and aconitase, we demonstrate that intensified carbon capture can be realized through such cascade enzymatic reactions. Experiments show that enhanced thermodynamic driving force for carbon conversion can be attained via pH control under ambient conditions, and that the cascade reactions have the potential to capture 0.5 mol carbon at pH 6 for each mole of substrate applied. Overall it manifests that the carbon capture capacity of biocatalytic reactions, in addition to be energy efficient, can also be ultimately intensified to approach those realized with chemical absorbents such as MEA. PMID:25708541

  7. High frequency energy cascades in inviscid hydrodynamics

    NASA Astrophysics Data System (ADS)

    Costa, Adam Smith N.; de Araújo, J. M.; Cohen, Nir; Lucena, Liacir S.; Viswanathan, G. M.

    2014-04-01

    With the aim of gaining insight into the notoriously difficult problem of energy and vorticity cascades in high dimensional incompressible flows, we take a simpler and very well understood low dimensional analog and approach it from a new perspective, using the Fourier transform. Specifically, we study, numerically and analytically, how kinetic energy moves from one scale to another in solutions of the hyperbolic or inviscid Burgers equation in one spatial dimension (1D). We restrict our attention to initial conditions which go to zero as x→±∞. The main result we report here is a Fourier analytic way of describing the cascade process. We find that the cascade proceeds by rapid growth of a crossover scale below which there is asymptotic power law decay of the magnitude of the Fourier transform.

  8. Geothermal systems of the Cascade Range

    USGS Publications Warehouse

    Muffler, L.J.; Bacon, Charles R.; Duffield, W.A.

    1982-01-01

    In the central and southern Cascade Range, plate convergence is oblique, and Quaternary volcanism produces mostly basalt and mafic andesite; large andesite-dacite composite volcanoes and silicic dome fields occur in restricted areas of long-lived igneous activity. To the north, plate convergence is normal, producing widely spaced centers in which mafic lavas are minor. Most Cascade volcanoes are short-lived and unlikely to be underlain at shallow levels by large magma bodies that could support high-temperature geothermal systems. Such systems are known, however, near Meager Mountain, at Newberry Volcano, and near Lassen Peak. Persistent fumaroles occur on several major composite volcanoes, but drilling to date has been insufficient to determine whether exploitable geothermal reservoirs occur at depth. Thermal springs away from the major volcanic centers are few and generally inconspicuous. However, significant geothermal systems along and west of the Cascade Range may well be masked by abundant cold ground water.

  9. Comparison between ARB and CARB processes on an AA5754/AA6061 composite

    NASA Astrophysics Data System (ADS)

    Verstraete, K.; Helbert, A.-L.; Brisset, F.; Baudin, T.

    2014-08-01

    The present work aims to compare two processes: Accumulative Roll Bonding and Cross Accumulative Roll Bonding (CARB). Both processes consist in the repetition of rolling but the second technique adds a 90° rotation of the sheet around its normal direction between each rolling. Microstructure, mechanical properties and texture were compared for both processes on an AA5754/AA6061 composite. As a result a thinner and less elongated microstructure was obtained in the CARB process leading to an isotropy and an improvement of the mechanical properties. Besides, the texture was characterized by the rotated Cube component for both processes but for CARB it is of less strength.

  10. Supramolecular Recognition of Amino Acids by Twisted Cucurbit[14]uril.

    PubMed

    Zhang, Jing; Xi, Yun-Yun; Li, Qing; Tang, Qing; Wang, Ruibing; Huang, Ying; Tao, Zhu; Xue, Sai-Feng; Lindoy, Leonard F; Wei, Gang

    2016-08-19

    Binding interactions between twisted cucurbit[14]uril (tQ[14]) and twenty standard amino acids (AAs) have been investigated by NMR spectroscopy and isothermal titration calorimetry (ITC) in aqueous HCl solutions and in DMSO. The results showed that tQ[14] displays clear binding affinity for AAs with a positively charged side chain or containing an aromatic ring, but weaker binding affinity for AAs with hydrophobic or polar side chains, with the binding mode depending on the type of side chain present in the AAs. PMID:27349365

  11. Fundamental Investigation of Circumferentially Varying Stator Cascades

    NASA Astrophysics Data System (ADS)

    Farnsworth, John A. N.

    2011-12-01

    The fundamentals of circumferentially varying stator cascades and their interactions with a downstream fixed pitch propeller were investigated experimentally utilizing multiple measurement techniques. The flow physics associated with the isolated circumferentially varying, or cyclic, stator cascade was studied in a wind tunnel environment through string tuft flow visualization, 2-D PIV, Stereoscopic PIV, and static surface pressure measurements. The coupled wake physics of the cyclic stator cascade with propeller were then investigated in a water tunnel using Stereo PIV. Finally, the global performance of components and the coupled system were quantified through force and moment measurements on the model in the water tunnel. A cyclic distribution of the stators' deflections resulted in non-axisymmetric distributions of the surface pressure and the flow field downstream of the stator array. In the model near wake the flow field is associated with secondary flow patterns in the form of coherent streamwise vortical structures that can be described by potential flow mechanisms. The collective pitch distribution of the stators produces a flow field that resembles a potential Rankine vortex, whereas the cyclic pitch distribution generates a flow pattern that can be described by a potential vortex pair in a cross flow. The stator distribution alone produces a significant side force that increases linearly with stator pitch amplitude. When a propeller is incorporated downstream from the cyclic cascade the side force from the stator cascade is reduced, but a small vertical force and pitching moment are created. The generation of these secondary forces and moments can be related to the redistribution of the tangential flow from the cyclic cascade into the axial direction by the retreating and advancing blade states of the fixed pitch propeller.

  12. Tandem Mass Spectrum Identification via Cascaded Search.

    PubMed

    Kertesz-Farkas, Attila; Keich, Uri; Noble, William Stafford

    2015-08-01

    Accurate assignment of peptide sequences to observed fragmentation spectra is hindered by the large number of hypotheses that must be considered for each observed spectrum. A high score assigned to a particular peptide-spectrum match (PSM) may not end up being statistically significant after multiple testing correction. Researchers can mitigate this problem by controlling the hypothesis space in various ways: considering only peptides resulting from enzymatic cleavages, ignoring possible post-translational modifications or single nucleotide variants, etc. However, these strategies sacrifice identifications of spectra generated by rarer types of peptides. In this work, we introduce a statistical testing framework, cascade search, that directly addresses this problem. The method requires that the user specify a priori a statistical confidence threshold as well as a series of peptide databases. For instance, such a cascade of databases could include fully tryptic, semitryptic, and nonenzymatic peptides or peptides with increasing numbers of modifications. Cascaded search then gradually expands the list of candidate peptides from more likely peptides toward rare peptides, sequestering at each stage any spectrum that is identified with a specified statistical confidence. We compare cascade search to a standard procedure that lumps all of the peptides into a single database, as well as to a previously described group FDR procedure that computes the FDR separately within each database. We demonstrate, using simulated and real data, that cascade search identifies more spectra at a fixed FDR threshold than with either the ungrouped or grouped approach. Cascade search thus provides a general method for maximizing the number of identified spectra in a statistically rigorous fashion. PMID:26084232

  13. Tandem Mass Spectrum Identification via Cascaded Search

    PubMed Central

    2016-01-01

    Accurate assignment of peptide sequences to observed fragmentation spectra is hindered by the large number of hypotheses that must be considered for each observed spectrum. A high score assigned to a particular peptide–spectrum match (PSM) may not end up being statistically significant after multiple testing correction. Researchers can mitigate this problem by controlling the hypothesis space in various ways: considering only peptides resulting from enzymatic cleavages, ignoring possible post-translational modifications or single nucleotide variants, etc. However, these strategies sacrifice identifications of spectra generated by rarer types of peptides. In this work, we introduce a statistical testing framework, cascade search, that directly addresses this problem. The method requires that the user specify a priori a statistical confidence threshold as well as a series of peptide databases. For instance, such a cascade of databases could include fully tryptic, semitryptic, and nonenzymatic peptides or peptides with increasing numbers of modifications. Cascaded search then gradually expands the list of candidate peptides from more likely peptides toward rare peptides, sequestering at each stage any spectrum that is identified with a specified statistical confidence. We compare cascade search to a standard procedure that lumps all of the peptides into a single database, as well as to a previously described group FDR procedure that computes the FDR separately within each database. We demonstrate, using simulated and real data, that cascade search identifies more spectra at a fixed FDR threshold than with either the ungrouped or grouped approach. Cascade search thus provides a general method for maximizing the number of identified spectra in a statistically rigorous fashion. PMID:26084232

  14. Temperature cascade control of distillation columns

    SciTech Connect

    Wolff, E.A.; Skogestad, S.

    1996-02-01

    This paper examines how difficult control tasks are enhanced by introducing secondary measurements, creating control cascades. Temperature is much used as secondary measurement because of cheap implementation and quick and accurate response. Distillation is often operated in this manner due to slow or lacking composition measurements, although the benefits have hardly been investigated closely, especially for multivariable control applications. The authors therefore use distillation as the example when quantifying improvements in interaction and disturbance rejection. They also give analytical expressions for the secondary controller gain. The improvements are reached through simple cascade operation of the control system and require no complicated estimator function.

  15. Experimental studies of cascade phenomena in metals

    SciTech Connect

    Jenkins, M.L.; Kirk, M.A.; Phythian, W.J.

    1992-06-01

    We review recent ion-irradiation experiments which have been performed to investigate the collapse of displacement cascades to dislocation loops in a range of metals and alloys. Many of the results including the dependencies of the collapse probabilities on irradiation temperature, and ion dose, energy and mass, can be explained within the framework of a thermal spike/cascade melting model which has been suggested by computer molecular dynamics simulations. Other aspects, such as the dependence of collapse propabilities on the crystal structure and the effects of alloying and impurities, are less well understood.

  16. Cascaded metasurfaces for broadband antenna isolation

    NASA Astrophysics Data System (ADS)

    Shrekenhamer, David; Miragliotta, Joseph A.; Scott, Robert; Jablon, Allan; Friedman, Jerry; Harshbarger, Derek; Sievenpiper, Daniel F.

    2015-09-01

    In this paper, we present a computational and experimental design of a metasurface for broadband microwave antenna isolation. Our current emphasis is on the development of a high-impedance surface (HIS) that enables broadband isolation between transmit and receive antennas. For our specific HIS, we have formed a cascade of HIS unit cells and have thus expanded the isolation to provide 56 dB/meter over one octave (7.5 to 18 GHz) relative to the bare metal ground plane. Computational models are used to design the cascaded structure to assure maximum isolation amplitude and bandwidth.

  17. DNA Targeting by a Minimal CRISPR RNA-Guided Cascade.

    PubMed

    Hochstrasser, Megan L; Taylor, David W; Kornfeld, Jack E; Nogales, Eva; Doudna, Jennifer A

    2016-09-01

    Bacteria employ surveillance complexes guided by CRISPR (clustered, regularly interspaced, short palindromic repeats) RNAs (crRNAs) to target foreign nucleic acids for destruction. Although most type I and type III CRISPR systems require four or more distinct proteins to form multi-subunit surveillance complexes, the type I-C systems use just three proteins to achieve crRNA maturation and double-stranded DNA target recognition. We show that each protein plays multiple functional and structural roles: Cas5c cleaves pre-crRNAs and recruits Cas7 to position the RNA guide for DNA binding and unwinding by Cas8c. Cryoelectron microscopy reconstructions of free and DNA-bound forms of the Cascade/I-C surveillance complex reveal conformational changes that enable R-loop formation with distinct positioning of each DNA strand. This streamlined type I-C system explains how CRISPR pathways can evolve compact structures that retain full functionality as RNA-guided DNA capture platforms. PMID:27588603

  18. Residue-specific force field based on the protein coil library. RSFF1: modification of OPLS-AA/L.

    PubMed

    Jiang, Fan; Zhou, Chen-Yang; Wu, Yun-Dong

    2014-06-26

    Traditional protein force fields use one set of parameters for most of the 20 amino acids (AAs), allowing transferability of the parameters. However, a significant shortcoming is the difficulty to fit the Ramachandran plots of all AA residues simultaneously, affecting the accuracy of the force field. In this Feature Article, we report a new strategy for protein force field parametrization. Backbone and side-chain conformational distributions of all 20 AA residues obtained from protein coil library were used as the target data. The dihedral angle (torsion) potentials and some local nonbonded (1-4/1-5/1-6) interactions in OPLS-AA/L force field were modified such that the target data can be excellently reproduced by molecular dynamics simulations of dipeptides (blocked AAs) in explicit water, resulting in a new force field with AA-specific parameters, RSFF1. An efficient free energy decomposition approach was developed to separate the corrections on ϕ and ψ from the two-dimensional Ramachandran plots. RSFF1 is shown to reproduce the experimental NMR (3)J-coupling constants of AA dipeptides better than other force fields. It has a good balance between α-helical and β-sheet secondary structures. It can successfully fold a set of α-helix proteins (Trp-cage and Homeodomain) and β-hairpins (Trpzip-2, GB1 hairpin), which cannot be consistently stabilized by other state-of-the-art force fields. Interestingly, the RSFF1 force field systematically overestimates the melting temperature (and the stability of native state) of these peptides/proteins. It has a potential application in the simulation of protein folding and protein structure refinement. PMID:24815738

  19. Ascorbic acid intake and oxalate synthesis.

    PubMed

    Knight, John; Madduma-Liyanage, Kumudu; Mobley, James A; Assimos, Dean G; Holmes, Ross P

    2016-08-01

    In humans, approximately 60 mg of ascorbic acid (AA) breaks down in the body each day and has to be replaced by a dietary intake of 70 mg in women and 90 mg in men to maintain optimal health and AA homeostasis. The breakdown of AA is non-enzymatic and results in oxalate formation. The exact amount of oxalate formed has been difficult to ascertain primarily due to the limited availability of healthy human tissue for such research and the difficulty in measuring AA and its breakdown products. The breakdown of 60 mg of AA to oxalate could potentially result in the formation of up to 30 mg oxalate per day. This exceeds our estimates of the endogenous production of 10-25 mg oxalate per day, indicating that degradative pathways that do not form oxalate exist. In this review, we examine what is known about the pathways of AA metabolism and how oxalate forms. We further identify how gaps in our knowledge may be filled to more precisely determine the contribution of AA breakdown to oxalate production in humans. The use of stable isotopes of AA to directly assess the conversion of vitamin to oxalate should help fill this void. PMID:27002809

  20. Habitat cascades: the conceptual context and global relevance of facilitation cascades via habitat formation and modification.

    PubMed

    Thomsen, Mads S; Wernberg, Thomas; Altieri, Andrew; Tuya, Fernando; Gulbransen, Dana; McGlathery, Karen J; Holmer, Marianne; Silliman, Brian R

    2010-08-01

    The importance of positive interactions is increasingly acknowledged in contemporary ecology. Most research has focused on direct positive effects of one species on another. However, there is recent evidence that indirect positive effects in the form of facilitation cascades can also structure species abundances and biodiversity. Here we conceptualize a specific type of facilitation cascade-the habitat cascade. The habitat cascade is defined as indirect positive effects on focal organisms mediated by successive facilitation in the form of biogenic formation or modification of habitat. Based on a literature review, we demonstrate that habitat cascades are a general phenomenon that enhances species abundance and diversity in forests, salt marshes, seagrass meadows, and seaweed beds. Habitat cascades are characterized by a hierarchy of facilitative interactions in which a basal habitat former (typically a large primary producer, e.g., a tree) creates living space for an intermediate habitat former (e.g., an epiphyte) that in turn creates living space for the focal organisms (e.g., spiders, beetles, and mites). We then present new data on a habitat cascade common to soft-bottom estuaries in which a relatively small invertebrate provides basal habitat for larger intermediate seaweeds that, in turn, generate habitat for focal invertebrates and epiphytes. We propose that indirect positive effects on focal organisms will be strongest when the intermediate habitat former is larger and different in form and function from the basal habitat former. We also discuss how humans create, modify, and destroy habitat cascades via global habitat destruction, climatic change, over-harvesting, pollution, or transfer of invasive species. Finally, we outline future directions for research that will lead to a better understanding of habitat cascades. PMID:21558196

  1. Preparation of thin film nanofibrous composite NF membrane based on EDC/NHS modified PAN-AA nanofibrous substrate

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Wang, X.; Hsiao, B. S.

    2016-07-01

    A novel kind of thin-film nanofibrous composite (TFNC) nanofiltration (NF) membranes consisting of a polyamide (PA) barrier layer were successfully fabricated by interfacial polymerization (IFP) based on electrospun double-layer nanofibrous substrates, which have an ultrathin poly (acrylonitrile-co-acrylic acid) (PAN-AA) nanofibrous layer as top layer and a thicker polyacrylonitrile (PAN) nanofiber layer as bottom porous support layer. Immersing PAN/PAN-AA nanofibrous substrates into 1-ethyl-(3-3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) aqueous solution and piperazine (PIP) aqueous solution (0.20 wt%) sequentially for a period of time, the carboxyl groups on PAN-AA nanofibers were activated by carbodiimide and then reacted with the amide groups. The as prepared composite membrane has an integrated structure with high rejection rate (98.0%); high permeate flux (40.4 L/m2h) for MgSO4 aqueous solution (2 g/L).

  2. Ascorbic acid and rates of cognitive decline in Alzheimer's disease.

    PubMed

    Bowman, Gene L; Dodge, Hiroko; Frei, Balz; Calabrese, Carlo; Oken, Barry S; Kaye, Jeffrey A; Quinn, Joseph F

    2009-01-01

    The brain maintains high levels of ascorbic acid (AA) despite a concentration gradient favoring diffusion from brain to peripheral tissues. Dietary antioxidants, including AA, appear to modify the risk of Alzheimer's disease (AD). The objective of this study was to test the hypothesis that neurodegeneration in AD is modified by brain levels of AA. Thirty-two patients with mild to moderate AD participated in a biomarker study involving standardized clinical assessments over one year. Cerebrospinal fluid (CSF) and serum were collected at baseline for AA and albumin content. Cognitive measures were collected at baseline and one year. CSF and plasma AA failed to predict cognitive decline independently, however, CSF: plasma AA ratio did. After adding CSF Albumin Index (an established marker of blood-brain barrier integrity) to the regression models the effect of CSF: plasma AA ratio as a predictor of cognitive decline was weakened. CSF: plasma AA ratio predicts rate of decline in AD. This relationship may indicate that the CSF: plasma AA ratio is an index of AA availability to the brain or may be an artifact of a relationship between blood-brain barrier impairment and neurodegeneration. PMID:19158425

  3. AAS Special Session: Policy Making in Astronomy

    NASA Astrophysics Data System (ADS)

    Cardelli, J. A.; Massa, D.

    1995-12-01

    The professional astronomical community today is more diverse than at any time in its history. Individuals participating in creative research programs can be found in a wide range of positions. This type of diversity, which mixes research, education, and service (e.g. contract) work, represents the strength of contemporary astronomy. While recognizing the unavoidable reductions in funding and restructuring of organizations like NASA, it is imperative that the significance of the current diversity be considered during these processes. Creative ideas are one of the cornerstones of quality research, and they can originate anywhere. Consequently, it is essential that adequate research resources remain available for free and open competition by all astronomers. Our goal in this session is to bring together officials from the AAS, NASA, and the NSF to discuss how the policy and decision making process operates and whether it should be changed to better serve the general needs of the professional astronomical community. Examples of the issues we believe are important include: In establishing new policy, how can the needs of the average research astronomer be better addressed? How could input from such astronomers be provided to those who craft NASA/NSF policy? How can/should the AAS serve as an interface between policy/decision making bodies and its membership? Should the AAS membership become more actively/effectively involved in the decision making process and, if so, how? More information on this session and related issues can be found at the Association of Research Astronomers Home Page: http://www.phy.vill.edu/astro/faculty/ara/ara_home.htm

  4. The jasmonate-responsive AaMYC2 transcription factor positively regulates artemisinin biosynthesis in Artemisia annua.

    PubMed

    Shen, Qian; Lu, Xu; Yan, Tingxiang; Fu, Xueqing; Lv, Zongyou; Zhang, Fangyuan; Pan, Qifang; Wang, Guofeng; Sun, Xiaofen; Tang, Kexuan

    2016-06-01

    The plant Artemisia annua is well known due to the production of artemisinin, a sesquiterpene lactone that is widely used in malaria treatment. Phytohormones play important roles in plant secondary metabolism, such as jasmonic acid (JA), which can induce artemisinin biosynthesis in A. annua. Nevertheless, the JA-inducing mechanism remains poorly understood. The expression of gene AaMYC2 was rapidly induced by JA and AaMYC2 binds the G-box-like motifs within the promoters of gene CYP71AV1 and DBR2, which are key structural genes in the artemisinin biosynthetic pathway. Overexpression of AaMYC2 in A. annua significantly activated the transcript levels of CYP71AV1 and DBR2, which resulted in an increased artemisinin content. By contrast, artemisinin content was reduced in the RNAi transgenic A. annua plants in which the expression of AaMYC2 was suppressed. Meanwhile, the RNAi transgenic A. annua plants showed lower sensitivity to methyl jasmonate treatment than the wild-type plants. These results demonstrate that AaMYC2 is a positive regulator of artemisinin biosynthesis and is of great value in genetic engineering of A. annua for increased artemisinin production. PMID:26864531

  5. Is the serum amyloid A protein in acute phase plasma high density lipoprotein the precursor of AA amyloid fibrils?

    PubMed Central

    Baltz, M L; Rowe, I F; Caspi, D; Turnell, W G; Pepys, M B

    1986-01-01

    Serum amyloid A protein (SAA), an apolipoprotein of high density lipoprotein (HDL), is generally considered to be the precursor of AA protein, which forms the fibrils in reactive systemic amyloidosis in man and animals. This view is based on amino acid sequence identity between AA and the amino-terminal portion of SAA. However, in extensive and well-controlled studies of experimentally induced murine AA amyloidosis, we were unable to demonstrate a direct precursor-product relationship between SAA, in SAA-rich HDL preparations from acute phase or amyloidotic mouse or human serum, and AA protein in the amyloid deposits. This raises the possibility that SAA in its usual form, as an apolipoprotein of HDL synthesized during the acute phase response, may not be the major precursor of AA fibrils. The amyloidogenic forms of circulating SAA molecules may not be isolated during the preparation of HDL. Alternatively, particularly in the light of recent evidence that SAA mRNA is expressed in many different tissues throughout the body of appropriately stimulated animals, amyloidogenic SAA may be derived from sources other than the liver cells in which SAA-rich HDL is synthesized. PMID:3105937

  6. Retargeting of the Bacillus thuringiensis toxin Cyt2Aa against hemipteran insect pests

    PubMed Central

    Chougule, Nanasaheb P.; Li, Huarong; Liu, Sijun; Linz, Lucas B.; Narva, Kenneth E.; Meade, Thomas; Bonning, Bryony C.

    2013-01-01

    Although transgenic crops expressing Bacillus thuringiensis (Bt) toxins have been used successfully for management of lepidopteran and coleopteran pest species, the sap-sucking insects (Hemiptera) are not particularly susceptible to Bt toxins. To overcome this limitation, we demonstrate that addition of a short peptide sequence selected for binding to the gut of the targeted pest species serves to increase toxicity against said pest. Insertion of a 12-aa pea aphid gut-binding peptide by adding to or replacing amino acids in one of three loops of the Bt cytolytic toxin, Cyt2Aa, resulted in enhanced binding and toxicity against both the pea aphid, Acyrthosiphon pisum, and the green peach aphid, Myzus persicae. This strategy may allow for transgenic plant-mediated suppression of other hemipteran pests, which include some of the most important pests of global agriculture. PMID:23650347

  7. Impact resistance of AA6005 panels

    NASA Astrophysics Data System (ADS)

    Clausen, A. H.; Borvik, T.; Hopperstad, O. S.; Langseth, M.

    2003-09-01

    The interest regarding use of extruded aluminium panels as lightweight protective structures is cmrently increasing. Even so, there are few experimental and computational investigations considering such structures. This paper presents some perforation tests on AA6005-T6 aluminium panels impacted by ogival-nose steel projectiles, where special emphasis was paid to the determination of the ballistic limit. Moreover, a material test programme including high strain rate tests using a split-Hopkinson tension bar was carried out in order to calibrate the Johnson-Cook constitutive model. Results from numerical analyses with LS-DYNA are finally included.

  8. cDNA cloning and expression of Bacillus thuringiensis Cry1Aa toxin binding 120 kDa aminopeptidase N from Bombyx mori.

    PubMed

    Yaoi, K; Nakanishi, K; Kadotani, T; Imamura, M; Koizumi, N; Iwahana, H; Sato, R

    1999-01-18

    Bacillus thuringiensis Cry1Aa toxin binds to a 120 kDa putative receptor protein in the Bombyx mori midgut. Recently, this protein was purified and identified as glycosyl-phosphatidylinositol (GPI) anchored aminopeptidase N (APN). In this study, a full-length cDNA thought to encode this 120 kDa APN was isolated and sequenced. It has a 2958 bp ORF encoding 986 amino acids. In the deduced amino acid sequence, we identified GPI-anchor and zinc-metallopeptidase signals, which are the same as those of APNs of other insects that are reported to be putative Cry1 toxin receptors. The B. mori APN amino acid sequence also has a high similarity with those of the other APNs. Subsequently, the recombinant APN was expressed by Escherichia coli and its Cry1Aa toxin binding ability was analyzed. Ligand blotting showed that Cry1Aa toxin bound to the recombinant APN. PMID:9931470

  9. Attenuated acute salivary α-amylase responses to gustatory stimulation with citric acid in thin children.

    PubMed

    Chen, Long Hui; Yang, Ze Min; Chen, Wei Wen; Lin, Jing; Zhang, Min; Yang, Xiao Rong; Zhao, Ling Bo

    2015-04-14

    Salivary α-amylase (sAA) is responsible for the 'pre-digestion' of starch in the oral cavity and accounts for up to 50 % of salivary protein in human saliva. An accumulating body of literature suggests that sAA is of nutritional importance; however, it is still not clear how sAA is related to individual's nutritional status. Although copy number variations (CNV) of the salivary amylase gene (AMY1) are associated with variation in sAA levels, a significant amount of sAA variation is not explained by AMY1 CNV. To measure sAA responses to gustatory stimulation with citric acid, we used sAA ratio (the ratio of stimulated sAA levels to those of resting sAA) and investigated acute sAA responses to citric acid in children with normal (Normal-BMI, n 22) and low (Low-BMI, n 21) BMI. The AMY1 gene copy number was determined by quantitative PCR. We, for the first time, demonstrated attenuated acute sAA responses (decreased sAA ratio) to gustatory stimulation in Low-BMI (thinness grade 3) children compared with the Normal-BMI children, which suggest that sAA responses to gustatory stimulation may be of nutritional importance. However, child's nutritional status was not directly related to their resting or stimulated sAA levels, and it was not associated with AMY1 gene copy number. Finally, AMY1 CNV might influence, but did not eventually determine, sAA levels in children. PMID:25784372

  10. Study on Fabrication of AA4032/AA6069 Cladding Billet Using Direct Chill Casting Process

    NASA Astrophysics Data System (ADS)

    Han, Xing; Zhang, Haitao; Shao, Bo; Li, Lei; Liu, Xuan; Cui, Jianzhong

    2016-04-01

    AA4032/AA6069 cladding billet in size of φ130 mm/φ110 mm was prepared by the modified direct chill casting process, and the parametric effect on casting performance was investigated using numerical simulation. Microstructures, elements distribution, and mechanical properties of the bonding interface were examined. The results show that metallurgical bonding interface can be obtained with the optimal parameters: the casting speed of 130 to 140 mm/min, the internal liquid level height of 50 to 60 mm, and the contact height of 40 to 50 mm. The metallurgical bonding interface is free of any discontinuities due to the fact that the alloying elements diffused across the interface and formed Ni-containing phase. Tensile strength of the cladding billet reaches 225.3 MPa, and the fracture position was located in AA6069 side, suggesting that the interface bonding strength is higher than the strength of AA6069. The interfacial shearing strength is 159.3 MPa, indicating excellent metallurgical bonding.

  11. Genetic loci that affect aristolochic acid-induced nephrotoxicity in the mouse

    PubMed Central

    2011-01-01

    Aristolochic acids (AA) are plant-derived nephrotoxins and carcinogens found in traditional medicines and herbal remedies. AA causes aristolochic acid nephropathy (AAN) and is a suspected environmental agent in Balkan endemic nephropathy (BEN) and its associated upper urothelial cancer. Approximately 5–10% of individuals exposed to AA develop renal insufficiency and/or cancer; thus a genetic predisposition to AA sensitivity has been proposed. The mouse is an established animal model of AAN, and inbred murine strains vary in AA sensitivity, confirming the genetic predisposition. We mapped quantitative trait loci (QTL) correlated with proximal tubule dysfunction after exposure to AA in an F2 population of mice, derived from breeding an AA-resistant strain (C57BL/6J) and an AA-sensitive strain (DBA/2J). A single main QTL was identified on chromosome 4 (Aanq1); three other interacting QTLs, (Aanq2–4) also were detected. The Aanq1 region was also detected in untreated mice, raising the possibility that preexisting differences in proximal tubule function may affect the severity of AA-elicited toxicity. This study lays the groundwork for identifying the genetic pathways contributing to AA sensitivity in the mouse and will further our understanding of human susceptibility to AA found widely in traditional medicines. PMID:21429970

  12. Impaired reductive regeneration of ascorbic acid in the Goto-Kakizaki diabetic rat.

    PubMed Central

    Kashiba, M; Oka, J; Ichikawa, R; Kageyama, A; Inayama, T; Kageyama, H; Ishikawa, T; Nishikimi, M; Inoue, M; Inoue, S

    2000-01-01

    Ascorbic acid (AA) is a naturally occurring major antioxidant that is essential for the scavenging of toxic free radicals in both plasma and tissues. AA levels in plasma and tissues have been reported to be significantly lower than normal in diabetic animals and humans, and might contribute to the complications found at the late stages of diabetes. In this study, plasma and hepatic AA levels and AA regeneration were studied in the Goto-Kakizaki diabetic rat (GK rat) to elucidate the mechanism of decreasing plasma and hepatic AA levels in diabetes. AA concentrations in the plasma and liver were significantly lower in GK than in control rats. AA levels in primary cultured hepatocytes derived from GK rats were lower than those derived from control Wistar rats with or without dehydroascorbic acid (DHA) in the medium. Among various enzyme activities that reduce DHA to AA, the NADPH-dependent regeneration of AA in the liver was significantly suppressed in GK rats. Northern blot analysis revealed that only the expression of 3-alpha-hydroxysteroid dehydrogenase (AKR) was significantly suppressed in these rats. These results suggest that decreased AA-regenerating activity, probably through decreased expression of AKR, contributes to the decreased AA levels and increased oxidative stress in GK rats. PMID:11023815

  13. Bacillus thuringiensis insecticidal Cry1Aa toxin binds to a highly conserved region of aminopeptidase N in the host insect leading to its evolutionary success.

    PubMed

    Nakanishi, K; Yaoi, K; Shimada, N; Kadotani, T; Sato, R

    1999-06-15

    Bacillus thuringiensis insecticidal protein, Cry1Aa toxin, binds to a specific receptor in insect midguts and has insecticidal activity. Therefore, the structure of the receptor molecule is probably a key factor in determining the binding affinity of the toxin and insect susceptibility. The cDNA fragment (PX frg1) encoding the Cry1Aa toxin-binding region of an aminopeptidase N (APN) or an APN family protein from diamondback moth, Plutella xylostella midgut was cloned and sequenced. A comparison between the deduced amino acid sequence of PX frg1 and other insect APN sequences shows that Cry1Aa toxin binds to a highly conserved region of APN family protein. In this paper, we propose a model to explain the mechanism that causes B. thuringiensis evolutionary success and differing insect susceptibility to Cry1Aa toxin. PMID:10366728

  14. OVERALL VIEW OF CASCADE CANAL COMPANY CRIB DAM, LOOKING UPSTREAM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERALL VIEW OF CASCADE CANAL COMPANY CRIB DAM, LOOKING UPSTREAM FROM DIRECTION OF KACHESS DAM. VIEW TO NORTH - Kachess Dam, 1904 Cascade Canal Company Crib Dam, Kachess River, 1.5 miles north of Interstate 90, Easton, Kittitas County, WA

  15. Modeling and simulation of cascading contingencies

    NASA Astrophysics Data System (ADS)

    Zhang, Jianfeng

    This dissertation proposes a new approach to model and study cascading contingencies in large power systems. The most important contribution of the work involves the development and validation of a heuristic analytic model to assess the likelihood of cascading contingencies, and the development and validation of a uniform search strategy. We model the probability of cascading contingencies as a function of power flow and power flow changes. Utilizing logistic regression, the proposed model is calibrated using real industry data. This dissertation analyzes random search strategies for Monte Carlo simulations and proposes a new uniform search strategy based on the Metropolis-Hastings Algorithm. The proposed search strategy is capable of selecting the most significant cascading contingencies, and it is capable of constructing an unbiased estimator to provide a measure of system security. This dissertation makes it possible to reasonably quantify system security and justify security operations when economic concerns conflict with reliability concerns in the new competitive power market environment. It can also provide guidance to system operators about actions that may be taken to reduce the risk of major system blackouts. Various applications can be developed to take advantage of the quantitative security measures provided in this dissertation.

  16. Forecasting Social Unrest Using Activity Cascades.

    PubMed

    Cadena, Jose; Korkmaz, Gizem; Kuhlman, Chris J; Marathe, Achla; Ramakrishnan, Naren; Vullikanti, Anil

    2015-01-01

    Social unrest is endemic in many societies, and recent news has drawn attention to happenings in Latin America, the Middle East, and Eastern Europe. Civilian populations mobilize, sometimes spontaneously and sometimes in an organized manner, to raise awareness of key issues or to demand changes in governing or other organizational structures. It is of key interest to social scientists and policy makers to forecast civil unrest using indicators observed on media such as Twitter, news, and blogs. We present an event forecasting model using a notion of activity cascades in Twitter (proposed by Gonzalez-Bailon et al., 2011) to predict the occurrence of protests in three countries of Latin America: Brazil, Mexico, and Venezuela. The basic assumption is that the emergence of a suitably detected activity cascade is a precursor or a surrogate to a real protest event that will happen "on the ground." Our model supports the theoretical characterization of large cascades using spectral properties and uses properties of detected cascades to forecast events. Experimental results on many datasets, including the recent June 2013 protests in Brazil, demonstrate the effectiveness of our approach. PMID:26091012

  17. A High Frequency Model of Cascade Noise

    NASA Technical Reports Server (NTRS)

    Envia, Edmane

    1998-01-01

    Closed form asymptotic expressions for computing high frequency noise generated by an annular cascade in an infinite duct containing a uniform flow are presented. There are two new elements in this work. First, the annular duct mode representation does not rely on the often-used Bessel function expansion resulting in simpler expressions for both the radial eigenvalues and eigenfunctions of the duct. In particular, the new representation provides an explicit approximate formula for the radial eigenvalues obviating the need for solutions of the transcendental annular duct eigenvalue equation. Also, the radial eigenfunctions are represented in terms of exponentials eliminating the numerical problems associated with generating the Bessel functions on a computer. The second new element is the construction of an unsteady response model for an annular cascade. The new construction satisfies the boundary conditions on both the cascade and duct walls simultaneously adding a new level of realism to the noise calculations. Preliminary results which demonstrate the effectiveness of the new elements are presented. A discussion of the utility of the asymptotic formulas for calculating cascade discrete tone as well as broadband noise is also included.

  18. Forecasting Social Unrest Using Activity Cascades

    PubMed Central

    Cadena, Jose; Korkmaz, Gizem; Kuhlman, Chris J.; Marathe, Achla; Ramakrishnan, Naren; Vullikanti, Anil

    2015-01-01

    Social unrest is endemic in many societies, and recent news has drawn attention to happenings in Latin America, the Middle East, and Eastern Europe. Civilian populations mobilize, sometimes spontaneously and sometimes in an organized manner, to raise awareness of key issues or to demand changes in governing or other organizational structures. It is of key interest to social scientists and policy makers to forecast civil unrest using indicators observed on media such as Twitter, news, and blogs. We present an event forecasting model using a notion of activity cascades in Twitter (proposed by Gonzalez-Bailon et al., 2011) to predict the occurrence of protests in three countries of Latin America: Brazil, Mexico, and Venezuela. The basic assumption is that the emergence of a suitably detected activity cascade is a precursor or a surrogate to a real protest event that will happen “on the ground.” Our model supports the theoretical characterization of large cascades using spectral properties and uses properties of detected cascades to forecast events. Experimental results on many datasets, including the recent June 2013 protests in Brazil, demonstrate the effectiveness of our approach. PMID:26091012

  19. Geothermal research, Oregon Cascades: Final technical report

    SciTech Connect

    Priest, G.R.; Black, G.L.

    1988-10-27

    Previous USDOE-funded geothermal studies have produced an extensive temperature gradient and heat flow data base for the State of Oregon. One of the important features identified as a result of these studies is a rapid transition from heat flow values on the order of 40 mW/m/sup 2/ in the Willamette Valley and Western Cascades to values of greater than or equal to100 mW/m/sup 2/ in the High Cascades and the eastern portion of the Western Cascades. These data indicate that the Cascade Range in Oregon has potential as a major geothermal province and stimulated much of the later work completed by government agencies and private industry. Additional data generated as a result of this grant and published in DOGAMI Open-File Report 0-86-2 further define the location and magnitude of this transition zone. In addition, abundant data collected from the vicinity of Breitenbush and Austin Hot Springs have permitted the formulation of relatively detailed models of these hydrothermal systems. These models are published in DOGAMI Open-File Report 0-88-5. Task 1.2 of the Deliverables section of Amendment M001 is fulfilled by DOGAMI publication GMS-48, Geologic map of the McKenzie Bridge quadrangle, Lane County, Oregon. This map was printed in October, 1988, and is part of the final submission to USDOE. 8 refs.

  20. Electrically Tunable Terahertz Quantum-Cascade Lasers

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath; Soidel, Alexander; Mansour, Kamjou

    2006-01-01

    Improved quantum-cascade lasers (QCLs) are being developed as electrically tunable sources of radiation in the far infrared spectral region, especially in the frequency range of 2 to 5 THz. The structures of QCLs and the processes used to fabricate them have much in common with those of multiple- quantum-well infrared photodetectors.

  1. Cascaded frequency doublers for broadband laser radiation

    SciTech Connect

    Andreev, N F; Vlasova, K V; Davydov, V S; Kulikov, S M; Makarov, A I; Sukharev, Stanislav A; Freidman, Gennadii I; Shubin, S V

    2012-10-31

    A new scheme of a cascaded converter of the first harmonic of broadband cw laser radiation into the second harmonic (SH) with compensation for the group walk-off in cascades is proposed and investigated. The conditions under which high conversion coefficients of broadband ({approx}33 cm{sup -1}) single-mode fibre laser radiation with low peak power ({approx}300 W) into the SH are determined for frequency doublers based on the most promising LBO crystal. Conversion of cw radiation with an average power of 300 W and efficiency {eta} = 4.5 % into the SH is obtained in a single LBO crystal. Effect of coherent addition of SH radiation excited in different cascades is demonstrated for two- and three-stage schemes. The expected conversion efficiencies, calculated disregarding loss but taking into account real aberrations of elements, are 18 % and 38 %, respectively. The effect of pumping depletion begins to manifest itself in the third cascade of a three-stage converter; it may reduce the latter value to {approx}30 %. (nonlinear optical phenomena)

  2. Cascaded frequency doublers for broadband laser radiation

    NASA Astrophysics Data System (ADS)

    Andreev, N. F.; Vlasova, K. V.; Davydov, V. S.; Kulikov, S. M.; Makarov, A. I.; Sukharev, Stanislav A.; Freidman, Gennadii I.; Shubin, S. V.

    2012-10-01

    A new scheme of a cascaded converter of the first harmonic of broadband cw laser radiation into the second harmonic (SH) with compensation for the group walk-off in cascades is proposed and investigated. The conditions under which high conversion coefficients of broadband (~33 cm-1) single-mode fibre laser radiation with low peak power (~300 W) into the SH are determined for frequency doublers based on the most promising LBO crystal. Conversion of cw radiation with an average power of 300 W and efficiency η = 4.5 % into the SH is obtained in a single LBO crystal. Effect of coherent addition of SH radiation excited in different cascades is demonstrated for two- and three-stage schemes. The expected conversion efficiencies, calculated disregarding loss but taking into account real aberrations of elements, are 18 % and 38 %, respectively. The effect of pumping depletion begins to manifest itself in the third cascade of a three-stage converter; it may reduce the latter value to ~30 %.

  3. Staged energy cascades for the LUX FEL

    SciTech Connect

    Penn, G.

    2004-07-27

    Designs and simulation studies for harmonic cascades, consisting of multiple stages of harmonic generation in free electron lasers (FELs), are presented as part of the LUX R&D project to design ultrafast, high photon energy light sources for basic science. Beam energies of 1.1, 2.1, and 3.1 GeV, corresponding to each pass through a recirculating linac, have independent designs for the harmonic cascade. Simulations were performed using the GENESIS FEL code, to obtain predictions for the performance of these cascades over a wide range of photon energies in terms of the peak power and laser profile. The output laser beam consists of photon energies of up to 1 keV, with durations of the order of 200 fs or shorter. The contribution of shot noise to the laser output is minimal, however fluctuations in the laser and electron beam properties can lead to variations in the FEL output. The sensitivity of the cascade to electron beam properties and misalignments is studied, taking advantage of the fact that GENESIS is a fully 3-dimensional code.

  4. The Attention Cascade Model and Attentional Blink

    ERIC Educational Resources Information Center

    Shih, Shui-I

    2008-01-01

    An attention cascade model is proposed to account for attentional blinks in rapid serial visual presentation (RSVP) of stimuli. Data were collected using single characters in a single RSVP stream at 10 Hz [Shih, S., & Reeves, A. (2007). "Attentional capture in rapid serial visual presentation." "Spatial Vision", 20(4), 301-315], and single words,…

  5. Nested Canalyzing, Unate Cascade, and Polynomial Functions.

    PubMed

    Jarrah, Abdul Salam; Raposa, Blessilda; Laubenbacher, Reinhard

    2007-09-15

    This paper focuses on the study of certain classes of Boolean functions that have appeared in several different contexts. Nested canalyzing functions have been studied recently in the context of Boolean network models of gene regulatory networks. In the same context, polynomial functions over finite fields have been used to develop network inference methods for gene regulatory networks. Finally, unate cascade functions have been studied in the design of logic circuits and binary decision diagrams. This paper shows that the class of nested canalyzing functions is equal to that of unate cascade functions. Furthermore, it provides a description of nested canalyzing functions as a certain type of Boolean polynomial function. Using the polynomial framework one can show that the class of nested canalyzing functions, or, equivalently, the class of unate cascade functions, forms an algebraic variety which makes their analysis amenable to the use of techniques from algebraic geometry and computational algebra. As a corollary of the functional equivalence derived here, a formula in the literature for the number of unate cascade functions provides such a formula for the number of nested canalyzing functions. PMID:18437250

  6. Experimental determination of unsteady blade element aerodynamics in cascades. Volume 1: Torsion mode cascade

    NASA Technical Reports Server (NTRS)

    Riffel, R. E.; Rothrock, M. D.

    1980-01-01

    A two dimensional cascade of harmonically oscillating airfoils was designed to model a near tip section from a rotor which was known to have experienced supersonic torsional flutter. This five bladed cascade had a solidity of 1.17 and a setting angle of 1.07 rad. Graphite epoxy airfoils were fabricated to achieve the realistically high reduced frequency level of 0.44. The cascade was tested over a range of static pressure ratios approximating the blade element operating conditions of the rotor along a constant speed line which penetrated the flutter boundary. The time-steady and time-unsteady flow field surrounding the center cascade airfoil were investigated. The effects of reduced solidity and decreased setting angle on the flow field were also evaluated.

  7. Asymmetric catalytic cascade reactions for constructing diverse scaffolds and complex molecules.

    PubMed

    Wang, Yao; Lu, Hong; Xu, Peng-Fei

    2015-07-21

    With the increasing concerns about chemical pollution and sustainability of resources, among the significant challenges facing synthetic chemists are the development and application of elegant and efficient methods that enable the concise synthesis of natural products, drugs, and related compounds in a step-, atom- and redox-economic manner. One of the most effective ways to reach this goal is to implement reaction cascades that allow multiple bond-forming events to occur in a single vessel. This Account documents our progress on the rational design and strategic application of asymmetric catalytic cascade reactions in constructing diverse scaffolds and synthesizing complex chiral molecules. Our research is aimed at developing robust cascade reactions for the systematic synthesis of a range of interesting molecules that contain structural motifs prevalent in natural products, pharmaceuticals, and biological probes. The strategies employed to achieve this goal can be classified into three categories: bifunctional base/Brønsted acid catalysis, covalent aminocatalysis/N-heterocyclic carbene catalysis, and asymmetric organocatalytic relay cascades. By the use of rationally designed substrates with properly reactive sites, chiral oxindole, chroman, tetrahydroquinoline, tetrahydrothiophene, and cyclohexane scaffolds were successfully assembled under bifunctional base/Brønsted acid catalysis from simple and readily available substances such as imines and nitroolefins. We found that some of these reactions are highly efficient since catalyst loadings as low as 1 mol % can promote the multistep sequences affording complex architectures with high stereoselectivities and yields. Furthermore, one of the bifunctional base/Brønsted acid-catalyzed cascade reactions for the synthesis of chiral cyclohexanes has been used as a key step in the construction of the tetracyclic core of lycorine-type alkaloids and the formal synthesis of α-lycorane. Guided by the principles of

  8. Dietary arachidonic acid in perinatal nutrition: a commentary.

    PubMed

    Lauritzen, Lotte; Fewtrell, Mary; Agostoni, Carlo

    2015-01-01

    Arachidonic acid (AA) is supplied together with docosahexaenoic acid (DHA) in infant formulas, but we have limited knowledge about the effects of supplementation with either of these long-chain polyunsaturated fatty acids (LCPUFA) on growth and developmental outcomes. AA is present in similar levels in breast milk throughout the world, whereas the level of DHA is highly diet dependent. Autopsy studies show similar diet-dependent variation in brain DHA, whereas AA is little affected by intake. Early intake of DHA has been shown to affect visual development, but the effect of LCPUFA on neurodevelopment remains to be established. Few studies have found any functional difference between infants supplemented with DHA alone compared to DHA+AA, but some studies show neurodevelopmental advantages in breast-fed infants of mothers supplemented with n-3 LCPUFA alone. It also remains to be established whether the AA/DHA balance could affect allergic and inflammatory outcomes later in life. Disentangling effects of genetic variability and dietary intake on AA and DHA-status and on functional outcomes may be an important step in the process of determining whether AA-intake is of any physiological or clinical importance. However, based on the current evidence we hypothesize that dietary AA plays a minor role on growth and development relative to the impact of dietary DHA. PMID:25314584

  9. The cytochrome P450 2AA gene cluster in zebrafish (Danio rerio); expression of CYP2AA1 and CYP2AA2 and response to phenobarbital-type inducers

    PubMed Central

    Kubota, Akira; Bainy, Afonso C.D.; Woodin, Bruce R.; Goldstone, Jared V.; Stegeman, John J.

    2013-01-01

    The cytochrome P450 (CYP) 2 gene family is the largest and most diverse CYP gene family in vertebrates. In zebrafish, we have identified 10 genes in a new subfamily CYP2AA, which does not show orthology to any human or other mammalian CYP genes. Here we report evolutionary and structural relationships of the 10 CYP2AA genes and expression of the first two genes, CYP2AA1 and CYP2AA2. Parsimony reconstruction of the tandem duplication pattern for the CYP2AA cluster suggests that CYP2AA1, CYP2AA2 and CYP2AA3 likely arose in the earlier duplication events and thus are most diverged in function from the other CYP2AAs. On the other hand, CYP2AA8 and CYP2AA9 are genes that arose in the latest duplication event, implying functional similarity between these two CYPs. A molecular model of CYP2AA1 showing the sequence conservation across the CYP2AA cluster reveals that the regions with the highest variability within the cluster map into CYP2AA1 near the substrate access channels, suggesting differing substrate specificity. Zebrafish CYP2AA1 transcript was expressed predominantly in intestine, while CYP2AA2 was most highly expressed in kidney, suggesting differing roles in physiology. In liver CYP2AA2 expression but not that of CYP2AA1, was increased by 1,4-bis [2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP) and, to a lesser extent, by phenobarbital (PB). In contrast, pregnenolone 16α-carbonitrile (PCN) increased CYP2AA1, but not CYP2AA2 in liver. The results identify a CYP2 subfamily in zebrafish that includes genes apparently induced by PB-type chemicals and PXR agonists, the first concrete in vivo evidence for a PB-type response in fish. PMID:23726801

  10. Arachidonic Acid Enhances Reproduction in Daphnia magna and Mitigates Changes in Sex Ratios Induced by Pyriproxyfen

    PubMed Central

    Ginjupalli, Gautam K.; Gerard, Patrick D.; Baldwin, William S.

    2016-01-01

    Arachidonic acid (AA) is one of only two unsaturated fatty acids retained in the ovaries of crustaceans, and an inhibitor of HR97g, a nuclear receptor expressed in adult ovaries. We hypothesized that as a key fatty acid, AA may be associated with reproduction and potentially environmental sex determination in Daphnia. Reproduction assays with AA indicate that it alters female/male sex ratios by increasing female production. This reproductive effect only occurred during a restricted P. subcapitata diet. Next, we tested whether enriching a poorer algal diet (C. vulgaris) with AA enhances overall reproduction and sex ratios. AA enrichment of a C. vulgaris diet also enhances fecundity at 1.0 and 4.0μM by 30–40% in the presence and absence of pyriproxyfen. This indicates that AA is crucial in reproduction regardless of environmental sex determination. Furthermore, our data indicates that P. subcapitata may provide a threshold concentration of AA needed for reproduction. Diet switch experiments from P. subcapitata to C. vulgaris mitigate some but not all of AA’s effects when compared to a C. vulgaris only diet, suggesting that some AA provided by P. subcapitata is retained. In summary, AA supplementation increases reproduction and represses pyriproxyfen-induced environmental sex determination in D. magna in restricted diets. A diet rich in AA may provide protection from some reproductive toxicants such as the juvenile hormone agonist, pyriproxyfen. PMID:25393616

  11. The ribosome can discriminate the chirality of amino acids within its peptidyl-transferase center.

    PubMed

    Englander, Michael T; Avins, Joshua L; Fleisher, Rachel C; Liu, Bo; Effraim, Philip R; Wang, Jiangning; Schulten, Klaus; Leyh, Thomas S; Gonzalez, Ruben L; Cornish, Virginia W

    2015-05-12

    The cellular translational machinery (TM) synthesizes proteins using exclusively L- or achiral aminoacyl-tRNAs (aa-tRNAs), despite the presence of D-amino acids in nature and their ability to be aminoacylated onto tRNAs by aa-tRNA synthetases. The ubiquity of L-amino acids in proteins has led to the hypothesis that D-amino acids are not substrates for the TM. Supporting this view, protein engineering efforts to incorporate D-amino acids into proteins using the TM have thus far been unsuccessful. Nonetheless, a mechanistic understanding of why D-aa-tRNAs are poor substrates for the TM is lacking. To address this deficiency, we have systematically tested the translation activity of D-aa-tRNAs using a series of biochemical assays. We find that the TM can effectively, albeit slowly, accept D-aa-tRNAs into the ribosomal aa-tRNA binding (A) site, use the A-site D-aa-tRNA as a peptidyl-transfer acceptor, and translocate the resulting peptidyl-D-aa-tRNA into the ribosomal peptidyl-tRNA binding (P) site. During the next round of continuous translation, however, we find that ribosomes carrying a P-site peptidyl-D-aa-tRNA partition into subpopulations that are either translationally arrested or that can continue translating. Consistent with its ability to arrest translation, chemical protection experiments and molecular dynamics simulations show that P site-bound peptidyl-D-aa-tRNA can trap the ribosomal peptidyl-transferase center in a conformation in which peptidyl transfer is impaired. Our results reveal a novel mechanism through which D-aa-tRNAs interfere with translation, provide insight into how the TM might be engineered to use D-aa-tRNAs, and increase our understanding of the physiological role of a widely distributed enzyme that clears D-aa-tRNAs from cells. PMID:25918365

  12. The ribosome can discriminate the chirality of amino acids within its peptidyl-transferase center

    PubMed Central

    Englander, Michael T.; Avins, Joshua L.; Fleisher, Rachel C.; Liu, Bo; Effraim, Philip R.; Wang, Jiangning; Schulten, Klaus; Leyh, Thomas S.; Gonzalez, Ruben L.; Cornish, Virginia W.

    2015-01-01

    The cellular translational machinery (TM) synthesizes proteins using exclusively L- or achiral aminoacyl-tRNAs (aa-tRNAs), despite the presence of D-amino acids in nature and their ability to be aminoacylated onto tRNAs by aa-tRNA synthetases. The ubiquity of L-amino acids in proteins has led to the hypothesis that D-amino acids are not substrates for the TM. Supporting this view, protein engineering efforts to incorporate D-amino acids into proteins using the TM have thus far been unsuccessful. Nonetheless, a mechanistic understanding of why D-aa-tRNAs are poor substrates for the TM is lacking. To address this deficiency, we have systematically tested the translation activity of D-aa-tRNAs using a series of biochemical assays. We find that the TM can effectively, albeit slowly, accept D-aa-tRNAs into the ribosomal aa-tRNA binding (A) site, use the A-site D-aa-tRNA as a peptidyl-transfer acceptor, and translocate the resulting peptidyl-D-aa-tRNA into the ribosomal peptidyl-tRNA binding (P) site. During the next round of continuous translation, however, we find that ribosomes carrying a P-site peptidyl-D-aa-tRNA partition into subpopulations that are either translationally arrested or that can continue translating. Consistent with its ability to arrest translation, chemical protection experiments and molecular dynamics simulations show that P site-bound peptidyl-D-aa-tRNA can trap the ribosomal peptidyl-transferase center in a conformation in which peptidyl transfer is impaired. Our results reveal a novel mechanism through which D-aa-tRNAs interfere with translation, provide insight into how the TM might be engineered to use D-aa-tRNAs, and increase our understanding of the physiological role of a widely distributed enzyme that clears D-aa-tRNAs from cells. PMID:25918365

  13. Multiperiod quantum-cascade nanoheterostructures: Epitaxy and diagnostics

    SciTech Connect

    Egorov, A. Yu. Brunkov, P. N.; Nikitina, E. V.; Pirogov, E. V.; Sobolev, M. S.; Lazarenko, A. A.; Baidakova, M. V.; Kirilenko, D. A.; Konnikov, S. G.

    2014-12-15

    Advances in the production technology of multiperiod nanoheterostructures of quantum-cascade lasers with 60 cascades by molecular-beam epitaxy (MBE) on an industrial multiple-substrate MBE machine are discussed. The results obtained in studying the nanoheterostructures of quantum-cascade lasers by transmission electron microscopy, high-resolution X-ray diffraction analysis, and photoluminescence mapping are presented.

  14. Convergence Analysis of a Cascade Architecture Neural Network

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A.; Stubberub, Allen R.; Daud, Taher; Thakoor, Anil

    1997-01-01

    In this paper, we present a mathematical foundation, including a convergence analysis, for cascading architecture neural networks. From this, a mathematical foundation for the casade correlation learning algorithm can also be found. Furthermore, it becomes apparent that the cascade correlation scheme is a special case of an efficient hardware learning algorithm called Cascade Error Projection.

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

    PubMed

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

    2016-01-01

    A simple liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) method for determination of the eicosapentaenoic acid (EPA) concentration to arachidonic acid (AA) concentration ratio in human saliva has been developed. The EPA/AA ratio in serum or plasma is widely recognized as a useful indicator in identifying the risk of cardiovascular disease, especially atherosclerosis. The salivary EPA/AA ratio is expected to be a convenient alternative to the serum or plasma EPA/AA ratio, because saliva offers the advantages of easy and noninvasive sampling. The saliva was deproteinized with acetonitrile, purified using an Oasis HLB cartridge, and derivatized with 1-[(4-dimethylaminophenyl)carbonyl]piperazine (DAPPZ). The derivatized EPA and AA were subjected to LC/ESI-MS/MS, and the EPA/AA ratio was determined using the selected reaction monitoring mode. The DAPPZ-derivatization increased the ESI sensitivity by 100- and 300-fold for EPA and AA, respectively, and enabled the detection of trace fatty acids in saliva using a 200 μL sample. The assay reproducibility was satisfactory (relative standard deviation, <5.0%). The method was successfully applied to the measurement of the salivary EPA/AA ratios of healthy Japanese subjects and their changes owing to the supplementation of EPA. PMID:25620210

  16. Effect of mitochondrial ascorbic acid synthesis on photosynthesis.

    PubMed

    Senn, M E; Gergoff Grozeff, G E; Alegre, M L; Barrile, F; De Tullio, M C; Bartoli, C G

    2016-07-01

    Ascorbic acid (AA) is synthesized in plant mitochondria through the oxidation of l-galactono-1,4-lactone (l-GalL) and then distributed to different cell compartments. AA-deficient Arabidopsis thaliana mutants (vtc2) and exogenous applications of l-GalL were used to generate plants with different AA content in their leaves. This experimental approach allows determining specific AA-dependent effects on carbon metabolism. No differences in O2 uptake, malic and citric acid and NADH content suggest that AA synthesis or accumulation did not affect mitochondrial activity; however, l-GalL treatment increased CO2 assimilation and photosynthetic electron transport rate in vtc2 (but not wt) leaves demonstrating a stimulation of photosynthesis after l-GalL treatment. Increased CO2 assimilation correlated with increased leaf stomatal conductance observed in l-GalL-treated vtc2 plants. PMID:27010742

  17. Microwave-Assisted γ-Valerolactone Production for Biomass Lignin Extraction: A Cascade Protocol.

    PubMed

    Tabasso, Silvia; Grillo, Giorgio; Carnaroglio, Diego; Calcio Gaudino, Emanuela; Cravotto, Giancarlo

    2016-01-01

    The general need to slow the depletion of fossil resources and reduce carbon footprints has led to tremendous effort being invested in creating "greener" industrial processes and developing alternative means to produce fuels and synthesize platform chemicals. This work aims to design a microwave-assisted cascade process for a full biomass valorisation cycle. GVL (γ-valerolactone), a renewable green solvent, has been used in aqueous acidic solution to achieve complete biomass lignin extraction. After lignin precipitation, the levulinic acid (LA)-rich organic fraction was hydrogenated, which regenerated the starting solvent for further biomass delignification. This process does not requires a purification step because GVL plays the dual role of solvent and product, while the reagent (LA) is a product of biomass delignification. In summary, this bio-refinery approach to lignin extraction is a cascade protocol in which the solvent loss is integrated into the conversion cycle, leading to simplified methods for biomass valorisation. PMID:27023511

  18. Enantioselective Synthesis of Dioxatriquinane Structural Motifs for HIV-1 Protease Inhibitors Using a Cascade Radical Cyclization†

    PubMed Central

    Ghosh, Arun K.; Xu, Chun-Xiao; Osswald, Heather L.

    2015-01-01

    Synthesis of novel HIV-1 protease inhibitors incorporating dioxatriquinane-derived P2-ligands is described. The tricyclic ligand alcohol contains five contiguous chiral centers. The ligand alcohols were prepared in optically active form by an enzymatic asymmetrization of mesodiacetate, cascade radical cyclization, and Lewis acid catalyzed reduction as the key steps. Inhibitors with dioxatriquinane-derived P2-ligands exhibited low nanomolar HIV-1 protease activity. PMID:26185337

  19. Carbazole Annulation via Cascade Nucleophilic Addition-Cyclization Involving 2-(Silyloxy)pentadienyl Cation.

    PubMed

    Stepherson, Jacob R; Ayala, Caitlan E; Tugwell, Thomas H; Henry, Jeffrey L; Fronczek, Frank R; Kartika, Rendy

    2016-06-17

    We report a new strategy toward the synthesis of highly functionalized carbazoles via 2-(silyloxy)pentadienyl cation intermediates, which were generated upon ionization of vinyl-substituted α-hydroxy silyl enol ethers under Brønsted acid catalysis. These electrophilic species were found to readily undergo cascade reactions with substituted indoles to generate carbazole molecular scaffolds in good yields via a sequence of regioselective nucleophilic addition, followed by intramolecular dehydrative cyclization. PMID:27265237

  20. Floor Plans: Section "AA", Section "BB"; Floor Framing Plans: Section ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Floor Plans: Section "A-A", Section "B-B"; Floor Framing Plans: Section "A-A", Section "B-B" - Fort Washington, Fort Washington Light, Northeast side of Potomac River at Fort Washington Park, Fort Washington, Prince George's County, MD

  1. Idiopathic systemic AA-amyloidosis in a skunk (Mephitis mephitis).

    PubMed

    Elhensheri, Mohamed; Linke, Reinhold P; Blankenburg, Anja; Beineke, Andreas

    2012-03-01

    This report describes a case of systemic amyloidosis in a captive striped skunk. At necropsy, bilateral alopecia, as well as reno-, hepato-, and splenomegaly were present. Congo red staining and immunohistochemistry revealed depositions of AA-amyloid in different organs. The lack of a predisposing disease is suggestive of idiopathic systemic AA-amyloidosis. PMID:22448530

  2. Quantum Cascade Lasers Modulation and Applications

    NASA Astrophysics Data System (ADS)

    Luzhansky, Edward

    The mid-wave IR (MWIR) spectral band, extending from 3 to 5 microns, is considered to be a low loss atmospheric window. There are several spectral sub-bands with relatively low atmospheric attenuation in this region making it popular for various commercial and military applications. Relatively low thermal and solar background emissions, effective penetration through the natural and anthropogenic obscurants and eye safety add to the long list of advantages of MWIR wavelengths. Quantum Cascade Lasers are compact semiconductor devices capable of operating in MWIR spectrum. They are based on inter-subband transitions in a multiple-quantum-well (QW) hetero-structure, designed by means of band-structure engineering. The inter-subband nature of the optical transition has several key advantages. First, the emission wavelength is primarily a function of the QW thickness. This characteristic allows choosing well-understood and reliable semiconductors for the generation of light in a wavelength range of interest. Second, a cascade process in which tens of photons are generated per injected electron. This cascading process is behind the intrinsic high-power capabilities of QCLs. This dissertation is focused on modulation properties of Quantum Cascade Lasers. Both amplitude and phase/frequency modulations were studied including modulation bandwidth, modulation efficiency and chirp linearity. Research was consisted of the two major parts. In the first part we describe the theory of frequency modulation (FM) response of Distributed Feedback Quantum Cascade Lasers (DFB QCL). It includes cascading effect on the QCL's maximum modulation frequency. The "gain levering" effect for the maximum FM response of the two section QCLs was studied as well. In the second part of research we concentrated on the Pulse Position Amplitude Modulation of a single section QCL. The low complexity, low size, weight and power Mid-Wavelength Infra-Red optical communications transceiver concept is

  3. Analytical model for electromagnetic cascades in rotating electric field

    SciTech Connect

    Nerush, E. N.; Bashmakov, V. F.; Kostyukov, I. Yu.

    2011-08-15

    Electromagnetic cascades attract a lot of attention as an important quantum electrodynamics effect that will reveal itself in various electromagnetic field configurations at ultrahigh intensities. We study cascade dynamics in rotating electric field analytically and numerically. The kinetic equations for the electron-positron plasma and gamma-quanta are formulated. The scaling laws are derived and analyzed. For the cascades arising far above the threshold the dependence of the cascade parameters on the field frequency is derived. The spectra of high-energy cascade particles are calculated. The analytical results are verified by numerical simulations.

  4. Supramolecular Adducts of Cucurbit[7]uril and Amino Acids in the Gas Phase

    NASA Astrophysics Data System (ADS)

    Kovalenko, Ekaterina; Vilaseca, Marta; Díaz-Lobo, Mireia; Masliy, A. N.; Vicent, Cristian; Fedin, Vladimir P.

    2016-02-01

    The complexation of the macrocyclic cavitand cucurbit[7]uril (Q7) with a series of amino acids (AA) with different side chains (Asp, Asn, Gln, Ser, Ala, Val, and Ile) is investigated by ESI-MS techniques. The 1:1 [Q7 + AA + 2H]2+ adducts are observed as the base peak when equimolar Q7:AA solutions are electrosprayed, whereas the 1:2 [Q7 + 2AA + 2H]2+ dications are dominant when an excess of the amino acid is used. A combination of ion mobility mass spectrometry (IM-MS) and DFT calculations of the 1:1 [Q7 + AA + 2H]2+ (AA = Tyr, Val, and Ser) adducts is also reported and proven to be unsuccessful at discriminating between exclusion or inclusion-type conformations in the gas phase. Collision induced dissociation (CID) revealed that the preferred dissociation pathways of the 1:1 [Q7 + AA + 2H]2+ dications are strongly influenced by the identity of the amino acid side chain, whereas ion molecule reactions towards N-butylmethylamine displayed a common reactivity pattern comprising AA displacement. Special emphasis is given on the differences between the gas-phase behavior of the supramolecular adducts with amino acids (AA = Asp, Asn, Gln, Ser, Ala, Val, and Ile) and those featuring basic (Lys and Arg) and aromatic (Tyr and Phe) side chains.

  5. Study of the Binding Energies between Unnatural Amino Acids and Engineered Orthogonal Tyrosyl-tRNA Synthetases

    PubMed Central

    Ren, Wei; Truong, Tan M.; Ai, Hui-wang

    2015-01-01

    We utilized several computational approaches to evaluate the binding energies of tyrosine (Tyr) and several unnatural Tyr analogs, to several orthogonal aaRSes derived from Methanocaldococcus jannaschii and Escherichia coli tyrosyl-tRNA synthetases. The present study reveals the following: (1) AutoDock Vina and ROSETTA were able to distinguish binding energy differences for individual pairs of favorable and unfavorable aaRS-amino acid complexes, but were unable to cluster together all experimentally verified favorable complexes from unfavorable aaRS-Tyr complexes; (2) MD-MM/PBSA provided the best prediction accuracy in terms of clustering favorable and unfavorable enzyme-substrate complexes, but also required the highest computational cost; and (3) MM/PBSA based on single energy-minimized structures has a significantly lower computational cost compared to MD-MM/PBSA, but still produced sufficiently accurate predictions to cluster aaRS-amino acid interactions. Although amino acid-aaRS binding is just the first step in a complex series of processes to acylate a tRNA with its corresponding amino acid, the difference in binding energy, as shown by MD-MM/PBSA, is important for a mutant orthogonal aaRS to distinguish between a favorable unnatural amino acid (unAA) substrate from unfavorable natural amino acid substrates. Our computational study should assist further designing and engineering of orthogonal aaRSes for the genetic encoding of novel unAAs. PMID:26220470

  6. Study of the Binding Energies between Unnatural Amino Acids and Engineered Orthogonal Tyrosyl-tRNA Synthetases

    NASA Astrophysics Data System (ADS)

    Ren, Wei; Truong, Tan M.; Ai, Hui-Wang

    2015-07-01

    We utilized several computational approaches to evaluate the binding energies of tyrosine (Tyr) and several unnatural Tyr analogs, to several orthogonal aaRSes derived from Methanocaldococcus jannaschii and Escherichia coli tyrosyl-tRNA synthetases. The present study reveals the following: (1) AutoDock Vina and ROSETTA were able to distinguish binding energy differences for individual pairs of favorable and unfavorable aaRS-amino acid complexes, but were unable to cluster together all experimentally verified favorable complexes from unfavorable aaRS-Tyr complexes; (2) MD-MM/PBSA provided the best prediction accuracy in terms of clustering favorable and unfavorable enzyme-substrate complexes, but also required the highest computational cost; and (3) MM/PBSA based on single energy-minimized structures has a significantly lower computational cost compared to MD-MM/PBSA, but still produced sufficiently accurate predictions to cluster aaRS-amino acid interactions. Although amino acid-aaRS binding is just the first step in a complex series of processes to acylate a tRNA with its corresponding amino acid, the difference in binding energy, as shown by MD-MM/PBSA, is important for a mutant orthogonal aaRS to distinguish between a favorable unnatural amino acid (unAA) substrate from unfavorable natural amino acid substrates. Our computational study should assist further designing and engineering of orthogonal aaRSes for the genetic encoding of novel unAAs.

  7. Differential effects of eicosapentaenoic and docosahexaenoic acids upon oxidant-stimulated release and uptake of arachidonic acid in human lymphoma U937 cells.

    PubMed

    Obajimi, Oluwakemi; Black, Kenneth D; MacDonald, Donald J; Boyle, Rose M; Glen, Iain; Ross, Brian M

    2005-08-01

    The use of n-3 polyunsaturated fatty acids, as found in fish-oil derived dietary supplements, as anti-inflammatory agents is supported by a variety of biochemical and physiological data. Recent studies investigating the therapeutic potential of long chain (>C20) n-3 fatty acids in mental illness have lead to the conclusion, however, that not all n-3 fatty acid types are equally efficacious. In particular eicosapentaeoic acid (EPA) appears to possess antidepressant and antipsychotic activity, while docosahexaenoic acid (DHA) does not, an effect suggested to be due to a differential ability to antagonize arachidonic acid (AA)-dependent cell signalling. In this study, we examine the effect of EPA and DHA supplementation upon uptake and release of arachidonic acid stimulated by tert-butyl hydroperoxide/Fe2+ in U937 cells. Oxidant-stimulated 3H-AA release from cells was enhanced by pre-treatment with EPA, DHA and AA, but not stearic or oleic acids for 18 days, with the order of effect magnitude being EPA > DHA = AA. Supplementation of cells for 1 day gave qualitatively similar results, although the effect magnitude was smaller. To determine whether enhanced release was due to decreased reuptake of AA, cells were cultured in the presence of 10 microM fatty acids. Pre-treatment of cells with EPA, and to a lesser extent AA, but not DHA, inhibited uptake of 3H-AA measured subsequent to the removal of unesterified fatty acids. This study suggests that, in U937 cells, EPA can alter the rate of uptake and release of AA from phospholipids in an exposure time-dependent manner, whereas DHA has no or little effect. Our results predict that EPA will have a more pronounced effect upon AA-dependent processes compared to DHA, and suggests that the relative amounts of EPA and DHA in fish oil supplements may modify their biochemical, and potentially, behavioural effects. PMID:15967385

  8. Reductive dechlorination of carbon tetrachloride using buffered alkaline ascorbic acid.

    PubMed

    Lin, Ya-Ting; Liang, Chenju

    2015-10-01

    Alkaline ascorbic acid (AA) was recently discovered as a novel in-situ chemical reduction (ISCR) reagent for remediating chlorinated solvents in the subsurface. For this ISCR process, the maintenance of an alkaline pH is essential. This study investigated the possibility of the reduction of carbon tetrachloride (CT) using alkaline AA solution buffered by phosphate and by NaOH. The results indicated that CT was reduced by AA, and chloroform (CF) was a major byproduct at a phosphate buffered pH of 12. However, CT was completely reduced by AA in 2M NaOH without CF formation. In the presence of iron/soil minerals, iron could be reduced by AA and Fe(2+) tends to precipitate on the mineral surface to accelerate CT degradation. A simultaneous transfer of hydrogenolysis and dichloroelimination would occur under phosphate buffered pH 12. This implies that a high alkaline environment is a crucial factor for maintaining the dominant pathway of two electron transfer from dianionic AA to dehydroascorbic acid, and to undergo dichloroelimination of CT. Moreover, threonic acid and oxalic acid were identified to be the major AA decomposition products in alkaline solutions. PMID:25912910

  9. States' Flexibility Waiver Plans for Alternate Assessments Based on Alternate Achievement Standards (AA-AAS). Synthesis Report 96

    ERIC Educational Resources Information Center

    Lazarus, Sheryl S.; Edwards, Lynn M.; Thurlow, Martha L.; Hodgson, Jennifer R.

    2014-01-01

    All states have alternate assessments based on alternate achievement standards (AA-AAS) for students with the most significant cognitive disabilities. For accountability purposes, the Elementary and Secondary Education Act (ESEA) allows up to 1% of students to be counted as proficient with this assessment option. In 2011 the U.S. Department of…

  10. Mutant Rep protein of the porcine circovirus type 2 N-glycosylation:23-25aa, 256-258aa mutation reduced virus replication but 286-288aa mutation enhanced virus replication in PK-15 cells.

    PubMed

    Shi, Jianli; Peng, Zhe; Fu, Fang; Xu, Shaojian; Xu, Shengnan; Cong, Xiaoyan; Yuan, Xiaoyuan; Yu, Jiang; Wu, Jiaqiang; Sun, Wenbo; Du, Yijun; Li, Jun; Wang, Jinbao

    2015-06-12

    Porcine circovirus type 2 (PCV2) Rep protein and the splice variant Rep' protein impact genome replication. The Rep protein contains three potential N-glycosylation at positions 23-25aa (NPS), 256-258aa (NQT) and 286-288aa (NAT). Three double copy infectious clones with Rep protein N-glycosylation at positions mutations 23-25aa (DPS), 256-258aa (DQT) and 286-288aa (DAT) were constructed and their function in virus replication in PK-15 cells was investigated. The results showed that the double copy infectious clone with N-glycosylation site mutation could be rescued in vitro and 23-25aa, 256-258aa mutation reduced virus replication but 286-288aa mutation enhanced virus replication. PMID:25829242

  11. Environmental solid particle effects on compressor cascade performance

    NASA Technical Reports Server (NTRS)

    Tabakoff, W.; Balan, C.

    1982-01-01

    The effect of suspended solid particles on the performance of the compressor cascade was investigated experimentally in a specially built cascade tunnel, using quartz sand particles. The cascades were made of NACA 65(10)10 airfoils. Three cascades were tested, one accelerating cascade and two diffusing cascades. The theoretical analysis assumes inviscid and incompressible two dimensional flow. The momentum exchange between the fluid and the particle is accounted for by the interphase force terms in the fluid momentum equation. The modified fluid phase momentum equations and the continuity equation are reduced to the conventional stream function vorticity formulation. The method treats the fluid phase in the Eulerian system and the particle phase in Lagrangian system. The experimental results indicate a small increase in the blade surface static pressures, while the theoretical results indicate a small decrease. The theoretical analysis, also predicts the loss in total pressure associated with the particulate flow through the cascade.

  12. Single mode terahertz quantum cascade amplifier

    SciTech Connect

    Ren, Y. Wallis, R.; Shah, Y. D.; Jessop, D. S.; Degl'Innocenti, R.; Klimont, A.; Kamboj, V.; Beere, H. E.; Ritchie, D. A.

    2014-10-06

    A terahertz (THz) optical amplifier based on a 2.9 THz quantum cascade laser (QCL) structure has been demonstrated. By depositing an antireflective coating on the QCL facet, the laser mirror losses are enhanced to fully suppress the lasing action, creating a THz quantum cascade (QC) amplifier. Terahertz radiation amplification has been obtained, by coupling a separate multi-mode THz QCL of the same active region design to the QC amplifier. A bare cavity gain is achieved and shows excellent agreement with the lasing spectrum from the original QCL without the antireflective coating. Furthermore, a maximum optical gain of ∼30 dB with single-mode radiation output is demonstrated.

  13. Cascade morphology transition in bcc metals.

    PubMed

    Setyawan, Wahyu; Selby, Aaron P; Juslin, Niklas; Stoller, Roger E; Wirth, Brian D; Kurtz, Richard J

    2015-06-10

    Energetic atom collisions in solids induce shockwaves with complex morphologies. In this paper, we establish the existence of a morphological transition in such cascades. The order parameter of the morphology is defined as the exponent, b, in the defect production curve as a function of cascade energy (N(F) ~ E(MD)(b)). Response of different bcc metals can be compared in a consistent energy domain when the energy is normalized by the transition energy, μ, between the high- and the low-energy regime. Using Cr, Fe, Mo and W data, an empirical formula of μ as a function of displacement threshold energy, E(d), is presented for bcc metals. PMID:25985256

  14. Cascade properties of shear Alfven wave turbulence

    NASA Technical Reports Server (NTRS)

    Bondeson, A.

    1985-01-01

    Nonlinear three-wave interactions of linear normal modes are investigated for two-dimensional incompressible magnetohydrodynamics and the weakly three-dimensional Strauss equations in the case where a strong uniform background field B0 is present. In both systems the only resonant interaction affecting Alfven waves is caused by the shear of the background field plus the zero frequency components of the perturbation. It is shown that the Alfven waves are cascaded in wavenumber space by a mechanism equivalent to the resonant absorption at the Alfven resonance. For large wavenumbers perpendicular to B0, the cascade is described by Hamilton's ray equations, dk/dt = -(first-order) partial derivative of omega with respect to vector r, where omega includes the effects of the zero frequency perturbations.

  15. Cascade Apartments: Deep Energy Multifamily Retrofit

    SciTech Connect

    Gordon, A.; Mattheis, L.; Kunkle, R.; Howard, L.; Lubliner, M.

    2014-02-01

    In December of 2009-10, King County Housing Authority (KCHA) implemented energy retrofit improvements in the Cascade multifamily community, located in Kent, Washington (marine climate.)This research effort involved significant coordination from stakeholders KCHA, WA State Department of Commerce, utility Puget Sound Energy, and Cascade tenants. This report focuses on the following three primary BA research questions : 1. What are the modeled energy savings using DOE low income weatherization approved TREAT software? 2. How did the modeled energy savings compare with measured energy savings from aggregate utility billing analysis? 3. What is the Savings to Investment Ratio (SIR) of the retrofit package after considering utility window incentives and KCHA capitol improvement funding.

  16. Cascade Apartments: Deep Energy Multifamily Retrofit

    SciTech Connect

    Gordon, A.; Mattheis, L.; Kunkle, R.; Howard, L.; Lubliner, M.

    2014-02-01

    In December of 2009-10, King County Housing Authority (KCHA) implemented energy retrofit improvements in the Cascade multifamily community, located in Kent, Washington (marine climate.)This research effort involved significant coordination from stakeholders KCHA, WA State Department of Commerce, utility Puget Sound Energy, and Cascade tenants. This report focuses on the following three primary BA research questions: 1. What are the modeled energy savings using DOE low income weatherization approved TREAT software? 2. How did the modeled energy savings compare with measured energy savings from aggregate utility billing analysis? 3. What is the Savings to Investment Ratio (SIR) of the retrofit package after considering utility window incentives and KCHA capitol improvement funding.

  17. Results from Grimethorpe PFBC turbine cascade tests

    SciTech Connect

    Not Available

    1986-12-01

    The test program at the Grimethorpe Pressurized Fluidized-Bed Combustion (PFBC) facility included an assessment of the potential for deposition, corrosion, and erosion of gas turbine blade materials when exposed to PFBC off gases. Flue gas from the combustor was fed through three stages of cyclones before entering the cascade. The impulse foils were approximately the size and shape of the first stage blades in the GE MS-1002 gas turbine. The cascade operated through three test series, accumulating a total of 649 hours. The conditions experienced are summarized. The paper lists the alloys tested, and discusses the efficiency of the cyclones, the particle size distribution of the dusts not removed by the cyclones, and corrosion of the turbine blades. 4 references, 1 figure, 2 tables.

  18. Cascade morphology transition in bcc metals

    SciTech Connect

    Setyawan, Wahyu; Selby, A.; Juslin, Niklas; Stoller, Roger E.; Wirth, Brian D.; Kurtz, Richard J.

    2015-06-10

    Energetic atom collisions in solids induce shockwaves with complex morphologies. In this paper, we establish the existence of a morphological transition in such cascades. The order parameter of the morphology is defined as the exponent, $b$, in the defect production curve as a function of cascade energy ($N_F$$ \\sim$$E_{MD}^b$). Response of different bcc metals can be compared in a consistent energy domain when the energy is normalized by the transition energy, $\\mu$, between the high- and the low-energy regime. Using Cr, Fe, Mo and W data, an empirical formula of $\\mu$ as a function of displacement threshold energy, $E_d$, is presented for bcc metals.

  19. Bowtie plasmonic quantum cascade laser antenna.

    PubMed

    Yu, Nanfang; Cubukcu, Ertugrul; Diehl, Laurent; Bour, David; Corzine, Scott; Zhu, Jintian; Höfler, Gloria; Crozier, Kenneth B; Capasso, Federico

    2007-10-01

    We report a bowtie plasmonic quantum cascade laser antenna that can confine coherent mid-infrared radiation well below the diffraction limit. The antenna is fabricated on the facet of a mid-infrared quantum cascade laser and consists of a pair of gold fan-like segments, whose narrow ends are separated by a nanometric gap. Compared with a nano-rod antenna composed of a pair of nano-rods, the bowtie antenna efficiently suppresses the field enhancement at the outer ends of the structure, making it more suitable for spatially-resolved high-resolution chemical and biological imaging and spectroscopy. The antenna near field is characterized by an apertureless near-field scanning optical microscope; field confinement as small as 130 nm is demonstrated at a wavelength of 7.0 mum. PMID:19550597

  20. Stability studies of ascorbic acid 2-glucoside in cosmetic lotion using surface response methodology.

    PubMed

    Huang, Wen-Ying; Lee, Pei-Chi; Huang, Ling-Kuei; Lu, Li-Ping; Liao, Wayne C

    2013-03-15

    Ascorbic acid 2-glucoside (AA-2G) has been widely used in cream and lotion types of cosmetic products. Thus, the degradation of AA-2G caused by the temperature change and pH variation was very critical for determining the bio-functionality of cosmetics. Response surface methodology (RSM) was introduced to study the influence of temperature and pH on the stability of AA-2G. The optimal condition of retaining AA-2G with the highest stability was determined to be 55.3°C and pH 6.4. The antioxidative activities of AA-2G including DPPH and ABTS free radical scavenging activities, metal chelating activity, and reducing ability were also determined. AA-2G was a good ascorbic acid derivative which could be used in cosmetic products as an active ingredient. PMID:23416010

  1. Structures of CRISPR Cas3 offer mechanistic insights into Cascade-activated DNA unwinding and degradation

    PubMed Central

    Huo, Yanwu; Nam, Ki Hyun; Ding, Fang; Lee, Heejin; Wu, Lijie; Xiao, Yibei; Farchione, F. Daniel; Zhou, Sharleen; Rajashankar, Raj; Kurinov, Igor; Zhang, Rongguang; Ke, Ailong

    2014-01-01

    CRISPR drives prokaryotic adaptation to invasive nucleic acids such as phages and plasmids using an RNA-mediated interference mechanism. Interference in Type I CRISPR-Cas systems requires a targeting Cascade complex and a degradation machine Cas3, which contains both nuclease and helicase activities. Here we report the crystal structures of Cas3 bound to ss-DNA substrate and show that it is an obligated 3′-to-5′ ss-DNase preferentially accepting substrate directly from the helicase moiety. Conserved residues in the HD-type nuclease coordinate two irons for ss-DNA cleavage. ATP coordination and conformational flexibility are revealed for the SF2-type helicase moiety. Cas3 is specifically guided towards Cascade-bound target DNA with a correct PAM sequence, through physical interactions to both the non-target substrate strand and the CasA protein. The cascade of recognition events ensures a well-controlled DNA targeting and degradation of alien DNA by Cascade and Cas3. PMID:25132177

  2. The boundary layer on compressor cascade blades

    NASA Technical Reports Server (NTRS)

    Deutsch, S.

    1981-01-01

    Some redesign of the cascade facility was necessary in order to incoporate the requirements of the LDA system into the design. Of particular importance was the intended use of a combination of suction upstream of the blade pack with diverging pack walls, as opposed to blade pack suction alone, for spanwise dimensionality control. An ARL blade was used to redo some tests using this arrangement. Preliminary testing and boundary layer measurements began on the double circular arc blades.

  3. A cascaded coding scheme for error control

    NASA Technical Reports Server (NTRS)

    Kasami, T.; Lin, S.

    1985-01-01

    A cascaded coding scheme for error control was investigated. The scheme employs a combination of hard and soft decisions in decoding. Error performance is analyzed. If the inner and outer codes are chosen properly, extremely high reliability can be attained even for a high channel bit-error-rate. Some example schemes are studied which seem to be quite suitable for satellite down-link error control.

  4. Evolution of Vertebrate Phototransduction: Cascade Activation

    PubMed Central

    Lamb, Trevor D.; Patel, Hardip; Chuah, Aaron; Natoli, Riccardo C.; Davies, Wayne I. L.; Hart, Nathan S.; Collin, Shaun P.; Hunt, David M.

    2016-01-01

    We applied high-throughput sequencing to eye tissue from several species of basal vertebrates (a hagfish, two species of lamprey, and five species of gnathostome fish), and we analyzed the mRNA sequences for the proteins underlying activation of the phototransduction cascade. The molecular phylogenies that we constructed from these sequences are consistent with the 2R WGD model of two rounds of whole genome duplication. Our analysis suggests that agnathans retain an additional representative (that has been lost in gnathostomes) in each of the gene families we studied; the evidence is strong for the G-protein α subunit (GNAT) and the cGMP phosphodiesterase (PDE6), and indicative for the cyclic nucleotide-gated channels (CNGA and CNGB). Two of the species (the hagfish Eptatretus cirrhatus and the lamprey Mordacia mordax) possess only a single class of photoreceptor, simplifying deductions about the composition of cascade protein isoforms utilized in their photoreceptors. For the other lamprey, Geotria australis, analysis of the ratios of transcript levels in downstream and upstream migrant animals permits tentative conclusions to be drawn about the isoforms used in four of the five spectral classes of photoreceptor. Overall, our results suggest that agnathan rod-like photoreceptors utilize the same GNAT1 as gnathostomes, together with a homodimeric PDE6 that may be agnathan-specific, whereas agnathan cone-like photoreceptors utilize a GNAT that may be agnathan-specific, together with the same PDE6C as gnathostomes. These findings help elucidate the evolution of the vertebrate phototransduction cascade from an ancestral chordate phototransduction cascade that existed prior to the vertebrate radiation. PMID:27189541

  5. Absorption spectroscopy with quantum cascade lasers

    NASA Technical Reports Server (NTRS)

    Kosterev, A. A.; Curl, R. F.; Tittel, F. K.; Gmachl, C.; Capasso, F.; Sivco, D. L.; Baillargeon, J. N.; Hutchinson, A. L.; Cho, A. Y.

    2001-01-01

    Novel pulsed and cw quantum cascade distributed feedback (QC-DFB) lasers operating near lambda=8 micrometers were used for detection and quantification of trace gases in ambient air by means of sensitive absorption spectroscopy. N2O, 12CH4, 13CH4, and different isotopic species of H2O were detected. Also, a highly selective detection of ethanol vapor in air with a sensitivity of 125 parts per billion by volume (ppb) was demonstrated.

  6. Evolution of Vertebrate Phototransduction: Cascade Activation.

    PubMed

    Lamb, Trevor D; Patel, Hardip; Chuah, Aaron; Natoli, Riccardo C; Davies, Wayne I L; Hart, Nathan S; Collin, Shaun P; Hunt, David M

    2016-08-01

    We applied high-throughput sequencing to eye tissue from several species of basal vertebrates (a hagfish, two species of lamprey, and five species of gnathostome fish), and we analyzed the mRNA sequences for the proteins underlying activation of the phototransduction cascade. The molecular phylogenies that we constructed from these sequences are consistent with the 2R WGD model of two rounds of whole genome duplication. Our analysis suggests that agnathans retain an additional representative (that has been lost in gnathostomes) in each of the gene families we studied; the evidence is strong for the G-protein α subunit (GNAT) and the cGMP phosphodiesterase (PDE6), and indicative for the cyclic nucleotide-gated channels (CNGA and CNGB). Two of the species (the hagfish Eptatretus cirrhatus and the lamprey Mordacia mordax) possess only a single class of photoreceptor, simplifying deductions about the composition of cascade protein isoforms utilized in their photoreceptors. For the other lamprey, Geotria australis, analysis of the ratios of transcript levels in downstream and upstream migrant animals permits tentative conclusions to be drawn about the isoforms used in four of the five spectral classes of photoreceptor. Overall, our results suggest that agnathan rod-like photoreceptors utilize the same GNAT1 as gnathostomes, together with a homodimeric PDE6 that may be agnathan-specific, whereas agnathan cone-like photoreceptors utilize a GNAT that may be agnathan-specific, together with the same PDE6C as gnathostomes. These findings help elucidate the evolution of the vertebrate phototransduction cascade from an ancestral chordate phototransduction cascade that existed prior to the vertebrate radiation. PMID:27189541

  7. Cascaded phase-preserving multilevel amplitude regeneration.

    PubMed

    Roethlingshoefer, Tobias; Onishchukov, Georgy; Schmauss, Bernhard; Leuchs, Gerd

    2014-12-29

    The performance of cascaded in-line phase-preserving amplitude regeneration using nonlinear amplifying loop mirrors has been studied in numerical simulations. As an example of a spectrally efficient modulation format with two amplitude states and multiple phase states, the regeneration performance of a star-16QAM format, basically an 8PSK format with two amplitude levels, was evaluated. An increased robustness against amplified spontaneous emission and nonlinear phase noise was observed resulting in a significantly increased transmission distance. PMID:25607142

  8. Vortex knot cascade in polynomial skein relations

    NASA Astrophysics Data System (ADS)

    Ricca, Renzo L.

    2016-06-01

    The process of vortex cascade through continuous reduction of topological complexity by stepwise unlinking, that has been observed experimentally in the production of vortex knots (Kleckner & Irvine, 2013), is shown to be reproduced in the branching of the skein relations of knot polynomials (Liu & Ricca, 2015) used to identify topological complexity of vortex systems. This observation can be usefully exploited for predictions of energy-complexity estimates for fluid flows.

  9. Cascade solar cell having conductive interconnects

    DOEpatents

    Borden, Peter G.; Saxena, Ram R.

    1982-10-26

    Direct ohmic contact between the cells in an epitaxially grown cascade solar cell is obtained by means of conductive interconnects formed through grooves etched intermittently in the upper cell. The base of the upper cell is directly connected by the conductive interconnects to the emitter of the bottom cell. The conductive interconnects preferably terminate on a ledge formed in the base of the upper cell.

  10. Modeling techniques for quantum cascade lasers

    SciTech Connect

    Jirauschek, Christian; Kubis, Tillmann

    2014-03-15

    Quantum cascade lasers are unipolar semiconductor lasers covering a wide range of the infrared and terahertz spectrum. Lasing action is achieved by using optical intersubband transitions between quantized states in specifically designed multiple-quantum-well heterostructures. A systematic improvement of quantum cascade lasers with respect to operating temperature, efficiency, and spectral range requires detailed modeling of the underlying physical processes in these structures. Moreover, the quantum cascade laser constitutes a versatile model device for the development and improvement of simulation techniques in nano- and optoelectronics. This review provides a comprehensive survey and discussion of the modeling techniques used for the simulation of quantum cascade lasers. The main focus is on the modeling of carrier transport in the nanostructured gain medium, while the simulation of the optical cavity is covered at a more basic level. Specifically, the transfer matrix and finite difference methods for solving the one-dimensional Schrödinger equation and Schrödinger-Poisson system are discussed, providing the quantized states in the multiple-quantum-well active region. The modeling of the optical cavity is covered with a focus on basic waveguide resonator structures. Furthermore, various carrier transport simulation methods are discussed, ranging from basic empirical approaches to advanced self-consistent techniques. The methods include empirical rate equation and related Maxwell-Bloch equation approaches, self-consistent rate equation and ensemble Monte Carlo methods, as well as quantum transport approaches, in particular the density matrix and non-equilibrium Green's function formalism. The derived scattering rates and self-energies are generally valid for n-type devices based on one-dimensional quantum confinement, such as quantum well structures.

  11. Cascade Raman soliton fiber ring laser

    SciTech Connect

    Gouveia-Neto, A.S.; Gomes, A.S.L.; Taylor, J.R.; Ainslie, B.J.; Craig, S.P.

    1987-11-01

    Pulses as short as 200 fsec at 1.5 ..mu..m and 230 fsec at 1.6 ..mu..m have been generated through a cascade Raman, solitonlike process in a fiber ring oscillator. A dispersion-shifted (lambda/sub 0/ = 1.46 ..mu..m) single-mode fiber was used as the gain medium, which was synchronously pumped by a cw mode-locked Nd:YAG laser operated at 1.32 ..mu..m.

  12. Gasdynamic evaluation of choking cascade turns

    NASA Astrophysics Data System (ADS)

    Perez, D. R.

    1984-12-01

    Uses for ram air in airborne vehicles are increasing along with the need for sophisticated ducting of the compressed air. Inlets operating supercritically, a normal shock in the subsonic diffuser, and use an aerodynamic grid to control the normal shock position to a region of low total pressure losses are discussed. Turning of the flow requires long radius curves to maintain the total pressure. This study combines the internal shock positioning and flow turning into a flow choking cascade turn with a short radius. Several sets of 90 degree turning sections, for turning compressed air, were selected, designed, and tested gas dynamically. Two of the turn sections were totally subsonic and only turned the air flow. Two other sections turned and choked the flow during supercritical inlet operation. These flow controllers perform the same function as an aerodynamic grid and flow turning vanes used in current internal compressible airflow designs. These tests correlated the suitability of using a water table versus a gas dynamic apparatus for determining the flow control capabilities and pressure recovery of the cascades. The subsonic only turning section gave the best pressure recovery and total pressure distribution along the turning axis, but allowed the supercritical internal shock to move towards large shock/boundary layer interaction. The two shock positioning cascades provided good internal shock control with only slightly lower pressure recovery. Further investigation is needed for the effects of back pressure fluctuations on the flow dynamics.

  13. Reconciliation of Cascade Impaction during Wet Nebulization.

    PubMed

    Solomita, Mario; Smaldone, Gerald C

    2009-03-01

    Cascade impaction is an important tool for measuring aerosol distributions from wet nebulizers; however, results vary depending on laboratory and technique. The focus of this study was to reconcile the contribution of particle evaporation to these reported differences. To measure the effect of evaporation, we compared aerosol distributions from circuits ventilated with humidified air, ambient air, and a nonventilated, standing cloud circuit using low-flow cascade impaction (1.0 L/min). Aerosol distributions were similar for the humidified/ventilated and standing cloud models [mass median aerodynamic diameter (MMAD) 3.4 microm, and 3.6 microm Aero-Eclipse, 5.8 and 5.1 microm Misty-Neb, 3.8 and 3.2 microm Pari LC Plus]. In the ventilated/ambient air model, smaller particle sizes were measured (2.2 microm AeroEclipse, 2.4 microm Misty-Neb, 2.1 microm Pari LC Plus). Techniques of cascade impaction significantly affected measured aerosol distributions. MMAD were defined by nebulizer type and conditions of particle evaporation not by impactor. Aerosol mixing with ambient air caused evaporation and shrinkage of particles, and accounts for differences between laboratories. Patients breathing from nebulizers may entrain ambient air possibly affecting deposition. PMID:19392585

  14. Cascade laser applications: trends and challenges

    NASA Astrophysics Data System (ADS)

    d'Humières, B.; Margoto, Éric; Fazilleau, Yves

    2016-03-01

    When analyses need rapid measurements, cost effective monitoring and miniaturization, tunable semiconductor lasers can be very good sources. Indeed, applications like on-field environmental gas analysis or in-line industrial process control are becoming available thanks to the advantage of tunable semiconductor lasers. Advances in cascade lasers (CL) are revolutionizing Mid-IR spectroscopy with two alternatives: interband cascade lasers (ICL) in the 3-6μm spectrum and quantum cascade lasers (QCL), with more power from 3 to 300μm. The market is getting mature with strong players for driving applications like industry, environment, life science or transports. CL are not the only Mid-IR laser source. In fact, a strong competition is now taking place with other technologies like: OPO, VCSEL, Solid State lasers, Gas, SC Infrared or fiber lasers. In other words, CL have to conquer a share of the Mid-IR application market. Our study is a market analysis of CL technologies and their applications. It shows that improvements of components performance, along with the progress of infrared laser spectroscopy will drive the CL market growth. We compare CL technologies with other Mid-IR sources and estimate their share in each application market.

  15. Analysis of Cascading Failure in Gene Networks

    PubMed Central

    Sun, Longxiao; Wang, Shudong; Li, Kaikai; Meng, Dazhi

    2012-01-01

    It is an important subject to research the functional mechanism of cancer-related genes make in formation and development of cancers. The modern methodology of data analysis plays a very important role for deducing the relationship between cancers and cancer-related genes and analyzing functional mechanism of genome. In this research, we construct mutual information networks using gene expression profiles of glioblast and renal in normal condition and cancer conditions. We investigate the relationship between structure and robustness in gene networks of the two tissues using a cascading failure model based on betweenness centrality. Define some important parameters such as the percentage of failure nodes of the network, the average size-ratio of cascading failure, and the cumulative probability of size-ratio of cascading failure to measure the robustness of the networks. By comparing control group and experiment groups, we find that the networks of experiment groups are more robust than that of control group. The gene that can cause large scale failure is called structural key gene. Some of them have been confirmed to be closely related to the formation and development of glioma and renal cancer respectively. Most of them are predicted to play important roles during the formation of glioma and renal cancer, maybe the oncogenes, suppressor genes, and other cancer candidate genes in the glioma and renal cancer cells. However, these studies provide little information about the detailed roles of identified cancer genes. PMID:23248647

  16. Degravitation features in the cascading gravity model

    NASA Astrophysics Data System (ADS)

    Moyassari, Parvin; Minamitsuji, Masato

    2013-07-01

    We obtain the effective gravitational equations on the codimension-2 and codimension-1 branes in the cascading gravity model. We then apply our formulation to the cosmological case and obtain the effective Friedmann equations on the codimension-2 brane, which are generically given in terms of integro-differential equations. Adopting an approximation for which the thickness of the codimension-2 brane is much smaller than the Hubble horizon, we study the Minkowski and de Sitter codimension-2 brane solutions. Studying the cosmological solutions shows that the cascading model exhibits the features necessary for degravitation of the cosmological constant. We also show that only the branch which does not have the smooth limit to the self-accelerating branch in the five-dimensional model in the absence of the bulk gravity can satisfy the null energy condition as the criterion of the stability. Note that our solutions are obtained in a different setup from that of the original cascading gravity model in the sense that the codimension-1 brane contains matter fields other than the pure tension.

  17. Prediction of Cascading Failures in Spatial Networks

    PubMed Central

    Shunkun, Yang; Dan, Lu

    2016-01-01

    Cascading overload failures are widely found in large-scale parallel systems and remain a major threat to system reliability; therefore, they are of great concern to maintainers and managers of different systems. Accurate cascading failure prediction can provide useful information to help control networks. However, for a large, gradually growing network with increasing complexity, it is often impractical to explore the behavior of a single node from the perspective of failure propagation. Fortunately, overload failures that propagate through a network exhibit certain spatial-temporal correlations, which allows the study of a group of nodes that share common spatial and temporal characteristics. Therefore, in this study, we seek to predict the failure rates of nodes in a given group using machine-learning methods. We simulated overload failure propagations in a weighted lattice network that start with a center attack and predicted the failure percentages of different groups of nodes that are separated by a given distance. The experimental results of a feedforward neural network (FNN), a recurrent neural network (RNN) and support vector regression (SVR) all show that these different models can accurately predict the similar behavior of nodes in a given group during cascading overload propagation. PMID:27093054

  18. HIV treatment cascade in tuberculosis patients

    PubMed Central

    Lessells, Richard J.; Swaminathan, Soumya; Godfrey-Faussett, Peter

    2015-01-01

    Purpose of review Globally, the number of deaths associated with tuberculosis (TB) and HIV coinfection remains unacceptably high. We review the evidence around the impact of strengthening the HIV treatment cascade in TB patients and explore recent findings about how best to deliver integrated TB/HIV services. Recent findings There is clear evidence that the timely provision of antiretroviral therapy (ART) reduces mortality in TB/HIV coinfected adults. Despite this, globally in 2013, only around a third of known HIV-positive TB cases were treated with ART. Although there is some recent evidence exploring the barriers to achieve high coverage of HIV testing and ART initiation in TB patients, our understanding of which factors are most important and how best to address these within different health systems remains incomplete. There are some examples of good practice in the delivery of integrated TB/HIV services to improve the HIV treatment cascade. However, evidence of the impact of such strategies is of relatively low quality for informing integrated TB/HIV programming more broadly. In most settings, there remain barriers to higher-level organizational and functional integration. Summary There remains a need for commitment to patient-centred integrated TB/HIV care in countries affected by the dual epidemic. There is a need for better quality evidence around how best to deliver integrated services to strengthen the HIV treatment cascade in TB patients, both at primary healthcare level and within community settings. PMID:26352390

  19. Cascade flutter analysis with transient response aerodynamics

    NASA Technical Reports Server (NTRS)

    Bakhle, M. A.; Mahajan, A. J.; Keith, T. G., Jr.; Stefko, G. L.

    1991-01-01

    Two methods for calculating linear frequency domain aerodynamic coefficients from a time marching Full Potential cascade solver are developed and verified. In the first method, the Influence Coefficient, solutions to elemental problems are superposed to obtain the solutions for a cascade in which all blades are vibrating with a constant interblade phase angle. The elemental problem consists of a single blade in the cascade oscillating while the other blades remain stationary. In the second method, the Pulse Response, the response to the transient motion of a blade is used to calculate influence coefficients. This is done by calculating the Fourier Transforms of the blade motion and the response. Both methods are validated by comparison with the Harmonic Oscillation method and give accurate results. The aerodynamic coefficients obtained from these methods are used for frequency domain flutter calculations involving a typical section blade structural model. An eigenvalue problem is solved for each interblade phase angle mode and the eigenvalues are used to determine aeroelastic stability. Flutter calculations are performed for two examples over a range of subsonic Mach numbers.

  20. Cascade flutter analysis with transient response aerodynamics

    NASA Technical Reports Server (NTRS)

    Bakhle, Milind A.; Mahajan, Aparajit J.; Keith, Theo G., Jr.; Stefko, George L.

    1991-01-01

    Two methods for calculating linear frequency domain aerodynamic coefficients from a time-marching Full-Potential cascade solver are developed and verified. In the first method, the Influence Coefficient method, solutions to elemental problems are superposed to obtain the solutions for a cascade in which all blades are vibrating with a constant interblade phase angle. The elemental problem consists of a single blade in the cascade oscillating while the other blades remain stationary. In the second method, the Pulse Response method, the response to the transient motion of a blade is used to calculate influence coefficients. This is done by calculating the Fourier transforms of the blade motion and the response. Both methods are validated by comparison with the Harmonic Oscillation method and give accurate results. The aerodynamic coefficients obtained from these methods are used for frequency domain flutter calculations involving a typical section blade structural model. An eigenvalue problem is solved for each interblade phase angle mode and the eigenvalues are used to determine aeroelastic stability. Flutter calculations are performed for two examples over a range of subsonic Mach numbers using both flat plates and actual airfoils.

  1. Contact sensitizers modulate the arachidonic acid metabolism of PMA-differentiated U-937 monocytic cells activated by LPS.

    PubMed

    Del Bufalo, Aurélia; Bernad, José; Dardenne, Christophe; Verda, Denis; Meunier, Jean Roch; Rousset, Françoise; Martinozzi-Teissier, Silvia; Pipy, Bernard

    2011-10-01

    For the effective induction of a hapten-specific T cell immune response toward contact sensitizers, in addition to covalent-modification of skin proteins, the redox and inflammatory statuses of activated dendritic cells are crucial. The aim of this study was to better understand how sensitizers modulate an inflammatory response through cytokines production and COX metabolism cascade. To address this purpose, we used the human monocytic-like U-937 cell line differentiated by phorbol myristate acetate (PMA) and investigated the effect of 6 contact sensitizers (DNCB, PPD, hydroquinone, propyl gallate, cinnamaldehyde and eugenol) and 3 non sensitizers (lactic acid, glycerol and tween 20) on the production of pro-inflammatory cytokines (IL-1β and TNF-α) and on the arachidonic acid metabolic profile after bacterial lipopolysaccharide (LPS) stimulation. Our results showed that among the tested molecules, all sensitizers specifically prevent the production of PMA/LPS-induced COX-2 metabolites (PGE(2,) TxB(2) and PGD(2)), eugenol and cinnamaldehyde inhibiting also the production of IL-1β and TNF-α. We further demonstrated that there is no unique PGE(2) inhibition mechanism: while the release of arachidonic acid (AA) from membrane phospholipids does not appear do be a target of modulation, COX-2 expression and/or COX-2 enzymatic activity are the major steps of prostaglandin synthesis that are inhibited by sensitizers. Altogether these results add a new insight into the multiple biochemical effects described for sensitizers. PMID:21807015

  2. Lower fetal status of docosahexaenoic acid, arachidonic acid and essential fatty acids is associated with less favorable neonatal neurological condition.

    PubMed

    Dijck-Brouwer, D A Janneke; Hadders-Algra, Mijna; Bouwstra, Hylco; Decsi, Tamás; Boehm, Günther; Martini, Ingrid A; Boersma, E Rudy; Muskiet, Frits A J

    2005-01-01

    Long-chain polyunsaturated fatty acids, notably arachidonic (AA) and docosahexaenoic (DHA) acids are abundant in brain and may be conditionally essential in fetal life. We investigated umbilical artery (UA) and vein (UV) fatty acid compositions and early neonatal neurological condition in 317 term infants. Neurological condition was summarized as a clinical classification and a 'neurological optimality score' (NOS). Neurologically abnormal infants (n=27) had lower UV DHA and essential fatty acid (EFA) status. NOS correlated positively with AA (UV), and EFA (UV) and DHA status (UV and UA) and negatively with 18:2omega6 and omega9 (UV), and 20:3omega9, omega7 and C18 trans fatty acids (UV and UA). UV DHA, AA, saturated fatty acids, gestational age and obstetrical optimality score explained 16.2% of the NOS variance. Early postnatal neurological condition seems negatively influenced by lower fetal DHA, AA and EFA status. C18 trans fatty acids and 18:2omega6 may exert negative effects by impairment of LCP status. PMID:15589396

  3. Nordihydroguaiaretic acid inhibits IFN-gamma-induced STAT tyrosine phosphorylation in rat brain astrocytes.

    PubMed

    Jeon, Sae-Bom; Ji, Kyung-Ae; You, Hye-Jin; Kim, Jae-Hong; Jou, Ilo; Joe, Eun-Hye

    2005-03-11

    The Janus kinase (JAK) and signal transducers and activators of transcription (STAT) signal cascades are major pathways that mediate the inflammatory functions of interferon-gamma (IFN-gamma), an important pro-inflammatory cytokine. Therefore, regulation of JAK/STAT signaling should modulate IFN-gamma-mediated inflammation. In this study, we found that nordihydroguaiaretic acid (NDGA), a well-known lipoxygenase (LO) inhibitor, suppressed IFN-gamma-induced inflammatory responses in brain astrocytes. In the presence of NDGA, interferon regulatory factor-1 expression was significantly reduced. Expression of monocyte chemotactic protein-1 and interferon-gamma inducible protein-10 mRNA in response to IFN-gamma was significantly suppressed in the presence of NDGA, as was tyrosine-phosphorylation of JAK and STAT. However, the 5-LO products, leukotriene B(4) (LTB(4)) and leukotriene C(4), were not detected in cells treated with IFN-gamma, indicating that the effect of NDGA seemed to be independent of 5-LO inhibition. In addition, two other 5-LO inhibitors (Rev5901 and AA861) did not mimic the effect of NDGA, and the 5-LO metabolites, 5-hydroxyeicosatetraenoic acid and LTB(4), were unable to reverse NDGA-driven suppression of STAT activation or affect basal STAT phosphorylation. Taken together, these results suggest that NDGA regulates IFN-gamma-mediated inflammation through mechanisms unrelated to the inhibition of 5-LO. PMID:15694390

  4. Structural basis for the varying propensities of different amino acids to adopt the collagen conformation.

    PubMed

    Raman, S Sundar; Gopalakrishnan, R; Wade, R C; Subramanian, V

    2011-03-24

    Although previous experimental studies have shown the positional preference of different amino acids (AAs) to form a stable triple helical collagen motif, the structural basis for the variations in the sequence and the positional propensity has not been systematically investigated. Thus, we have here probed the origin of the structural stability offered by the 20 naturally occurring AAs to collagen by means of classical molecular dynamics (MD) simulation. Simulations were carried out on 39 collagen-like peptides employing a host-guest approach. The results show that the propensity of the different AAs to adopt collagen-like conformations depends primarily on their ϕ and ψ angle preferences. Changes in these angles upon substitution of different AAs in the X(AA) and Y(AA) positions in the canonical ((Gly-X(AA)-Y(AA))(7))(3) motif dictate the formation of interchain hydrogen bonds, solvent interactions, and puckering of neighboring imino acids and, thus, the structural stability of the collagen. The role of solvent-mediated hydrogen bonds in the stabilization of collagen has also been elucidated from the MD simulations. In addition to the conventional hydrogen bonds known to be present in collagen, a hitherto unidentified direct interchain hydrogen bond, between the X(AA) N-H group and the Hyp O-H group of the neighboring chain, was observed during the simulations. Its occupancy was ∼36% when Leu was present at the X(AA) position. PMID:21361324

  5. Uptake and release of adrenal ascorbic acid in the guinea pig after injection of ACTH

    SciTech Connect

    Kipp, D.E.; Rivers, J.M.

    1987-09-01

    The effect of a single injection of ACTH (3 IU/100 g body weight) on the distribution of ascorbic acid (AA) and radiolabeled AA in 20 tissues was studied in adult male guinea pigs consuming 500 mg AA/kg diet. Saline- or ACTH-injected animals were simultaneously injected with (1-/sup 14/C)AA, and killed at 0.5, 1, 2, 4 and 6 h after injection. There was no significant difference between treatments in the weight of any tissue over the 6-h experimental period. As anticipated, the concentration of AA in the adrenals of animals injected with ACTH was 33% of that of animals injected with saline at 4 h. Unexpectedly, the concentration of radiolabeled AA in the adrenals at 0.5 h after ACTH injection was 172% of that after saline injection. The concentration of radiolabeled AA in the adrenal of the saline-injected animals increased slowly over time to reach a level similar to that of ACTH-injected animals by 6 h. There was no effect of ACTH on the level of AA or uptake in any of the other tissues examined. These results demonstrate that a single dose of ACTH markedly influences the retention of AA in the adrenal gland without similarly altering retention of AA in other tissues. Furthermore, ACTH treatment causes both accelerated uptake and release of AA into the adrenals.

  6. Isoliquiritigenin induces growth inhibition and apoptosis through downregulating arachidonic acid metabolic network and the deactivation of PI3K/Akt in human breast cancer

    SciTech Connect

    Li, Ying; Zhao, Haixia; Wang, Yuzhong; Zheng, Hao; Yu, Wei; Chai, Hongyan; Zhang, Jing; Falck, John R.; Guo, Austin M.; Yue, Jiang; Peng, Renxiu; Yang, Jing

    2013-10-01

    Arachidonic acid (AA)-derived eicosanoids and its downstream pathways have been demonstrated to play crucial roles in growth control of breast cancer. Here, we demonstrate that isoliquiritigenin, a flavonoid phytoestrogen from licorice, induces growth inhibition and apoptosis through downregulating multiple key enzymes in AA metabolic network and the deactivation of PI3K/Akt in human breast cancer. Isoliquiritigenin diminished cell viability, 5-bromo-2′-deoxyuridine (BrdU) incorporation, and clonogenic ability in both MCF-7 and MDA-MB-231cells, and induced apoptosis as evidenced by an analysis of cytoplasmic histone-associated DNA fragmentation, flow cytometry and hoechst staining. Furthermore, isoliquiritigenin inhibited mRNA expression of multiple forms of AA-metabolizing enzymes, including phospholipase A2 (PLA2), cyclooxygenases (COX)-2 and cytochrome P450 (CYP) 4A, and decreased secretion of their products, including prostaglandin E{sub 2} (PGE{sub 2}) and 20-hydroxyeicosatetraenoic acid (20-HETE), without affecting COX-1, 5-lipoxygenase (5-LOX), 5-lipoxygenase activating protein (FLAP), and leukotriene B{sub 4} (LTB{sub 4}). In addition, it downregulated the levels of phospho-PI3K, phospho-PDK (Ser{sup 241}), phospho-Akt (Thr{sup 308}), phospho-Bad (Ser{sup 136}), and Bcl-x{sub L} expression, thereby activating caspase cascades and eventually cleaving poly(ADP-ribose) polymerase (PARP). Conversely, the addition of exogenous eicosanoids, including PGE{sub 2}, LTB{sub 4} and a 20-HETE analog (WIT003), and caspase inhibitors, or overexpression of constitutively active Akt reversed isoliquiritigenin-induced apoptosis. Notably, isoliquiritigenin induced growth inhibition and apoptosis of MDA-MB-231 human breast cancer xenografts in nude mice, together with decreased intratumoral levels of eicosanoids and phospho-Akt (Thr{sup 308}). Collectively, these data suggest that isoliquiritigenin induces growth inhibition and apoptosis through downregulating AA metabolic

  7. Protein Restriction with Amino Acid-Balanced Diets Shrinks Circulating Pool Size of Amino Acid by Decreasing Expression of Specific Transporters in the Small Intestine.

    PubMed

    Qiu, Kai; Qin, Chun Fu; Luo, Min; Zhang, Xin; Sun, Wen Juan; Jiao, Ning; Li, De Fa; Yin, Jing Dong

    2016-01-01

    Dietary protein restriction is not only beneficial to health and longevity in humans, but also protects against air pollution and minimizes feeding cost in livestock production. However, its impact on amino acid (AA) absorption and metabolism is not quite understood. Therefore, the study aimed to explore the effect of protein restriction on nitrogen balance, circulating AA pool size, and AA absorption using a pig model. In Exp.1, 72 gilts weighting 29.9 ± 1.5 kg were allocated to 1 of the 3 diets containing 14, 16, or 18% CP for a 28-d trial. Growth (n = 24), nitrogen balance (n = 6), and the expression of small intestinal AA and peptide transporters (n = 6) were evaluated. In Exp.2, 12 barrows weighting 22.7 ± 1.3 kg were surgically fitted with catheters in the portal and jejunal veins as well as the carotid artery and assigned to a diet containing 14 or 18% CP. A series of blood samples were collected before and after feeding for determining the pool size of circulating AA and AA absorption in the portal vein, respectively. Protein restriction did not sacrifice body weight gain and protein retention, since nitrogen digestibility was increased as dietary protein content reduced. However, the pool size of circulating AA except for lysine and threonine, and most AA flux through the portal vein were reduced in pigs fed the low protein diet. Meanwhile, the expression of peptide transporter 1 (PepT-1) was stimulated, but the expression of the neutral and cationic AA transporter systems was depressed. These results evidenced that protein restriction with essential AA-balanced diets, decreased AA absorption and reduced circulating AA pool size. Increased expression of small intestinal peptide transporter PepT-1 could not compensate for the depressed expression of jejunal AA transporters for AA absorption. PMID:27611307

  8. Detection of calcium based neutralizers in milk and milk products by AAS.

    PubMed

    Sowmya, R; Indumathi, K P; Arora, S; Sharma, V; Singh, A K

    2015-02-01

    Current study was carried out with the intent to standardize detection and estimation method for calcium (Ca) based neutralizers in milk and milk based indigenous products (khoa and paneer) using atomic absorption spectroscopy (AAS). Neutralized milk, khoa and paneer samples were prepared using milk with developed acidity to which calculated quantity of neutralizer (Ca based) was added. Rosalic acid test results get masked at times due to developed acidity which neutralizes the alkalinity imparted by neutralizer and hence gives false result with time in neutralizer added samples. Atomic absorption spectroscopy proved to be an accurate estimate which could detect the abnormal rise in mineral concentration even with slight addition of neutralizers in comparison with control milk and milk products. Formalin, which is a commonly used preservative in milk samples for chemical analysis, did not have any significant impact on estimation of calcium in the neutralized milk during storage. PMID:25694738

  9. Induction of the endoplasmic reticulum stress and autophagy in human lung carcinoma A549 cells by anacardic acid.

    PubMed

    Seong, Yeong-Ae; Shin, Pyung-Gyun; Yoon, Jin-Soo; Yadunandam, Anandam Kasin; Kim, Gun-Do

    2014-03-01

    Anacardic acid (AA, 2-hydroxy-6-pentadecylbenzoic acid), a constituent of the cashew-nut shell, has a variety of beneficial effects on the treatment of cancer and tumors. However, the fact that AA induces ER stress and autophagy in cancer cell is not known. We investigated the effect of AA on ER-stress and autophagy-induced cell death in cancer cells. Because of our interest in lung cancer, we used the non-small cell lung adenocarcinoma A549 cells treated with 3.0 μg/ml of AA for this research. In this research we found that AA induces intracellular Ca(2+) mobilization and ER stress. AA induced the ER stress-inducing factors, especially IRE1α, and the hallmarks of UPR, Grp78/Bip and GADD153/CHOP. AA inhibited the expression of p-PERK and its downstream substrate, p-elF2α. We also demonstrated that AA induces autophagy. Up-regulation of autophagy-related genes and the appearance of autophagosome in transfected cells with green fluorescent protein (GFP)-LC3 and GFP-Beclin1 plasmids showed the induction of autophagy in AA-treated A549 cells. The morphological analysis of intracellular organelles by TEM also showed the evidence that AA induces ER stress and autophagy. For the first time, our research showed that AA induces ER stress and autophagy in cancer cells. PMID:23955513

  10. Carbon Dots and 9AA as a Binary Matrix for the Detection of Small Molecules by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Chen, Yongli; Gao, Dan; Bai, Hangrui; Liu, Hongxia; Lin, Shuo; Jiang, Yuyang

    2016-07-01

    Application of matrix-assisted laser-desorption/ionization mass spectrometry (MALDI MS) to analyze small molecules have some limitations, due to the inhomogeneous analyte/matrix co-crystallization and interference of matrix-related peaks in low m/z region. In this work, carbon dots (CDs) were for the first time applied as a binary matrix with 9-Aminoacridine (9AA) in MALDI MS for small molecules analysis. By 9AA/CDs assisted desorption/ionization (D/I) process, a wide range of small molecules, including nucleosides, amino acids, oligosaccharides, peptides, and anticancer drugs with a higher sensitivity were demonstrated in the positive ion mode. A detection limit down to 5 fmol was achieved for cytidine. 9AA/CDs matrix also exhibited excellent reproducibility compared with 9AA matrix. Moreover, by exploring the ionization mechanism of the matrix, the influence factors might be attributed to the four parts: (1) the strong UV absorption of 9AA/CDs due to their π-conjugated network; (2) the carboxyl groups modified on the CDs surface act as protonation sites for proton transfer in positive ion mode; (3) the thin layer crystal of 9AA/CDs could reach a high surface temperature more easily and lower transfer energy for LDI MS; (4) CDs could serve as a matrix additive to suppress 9AA ionization. Furthermore, this matrix was allowed for the analysis of glucose as well as nucleosides in human urine, and the level of cytidine was quantified with a linear range of 0.05-5 mM (R2 > 0.99). Therefore, the 9AA/CDs matrix was proven to be an effective MALDI matrix for the analysis of small molecules with improved sensitivity and reproducibility. This work provides an alternative solution for small molecules detection that can be further used in complex samples analysis.

  11. Carbon Dots and 9AA as a Binary Matrix for the Detection of Small Molecules by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry.

    PubMed

    Chen, Yongli; Gao, Dan; Bai, Hangrui; Liu, Hongxia; Lin, Shuo; Jiang, Yuyang

    2016-07-01

    Application of matrix-assisted laser-desorption/ionization mass spectrometry (MALDI MS) to analyze small molecules have some limitations, due to the inhomogeneous analyte/matrix co-crystallization and interference of matrix-related peaks in low m/z region. In this work, carbon dots (CDs) were for the first time applied as a binary matrix with 9-Aminoacridine (9AA) in MALDI MS for small molecules analysis. By 9AA/CDs assisted desorption/ionization (D/I) process, a wide range of small molecules, including nucleosides, amino acids, oligosaccharides, peptides, and anticancer drugs with a higher sensitivity were demonstrated in the positive ion mode. A detection limit down to 5 fmol was achieved for cytidine. 9AA/CDs matrix also exhibited excellent reproducibility compared with 9AA matrix. Moreover, by exploring the ionization mechanism of the matrix, the influence factors might be attributed to the four parts: (1) the strong UV absorption of 9AA/CDs due to their π-conjugated network; (2) the carboxyl groups modified on the CDs surface act as protonation sites for proton transfer in positive ion mode; (3) the thin layer crystal of 9AA/CDs could reach a high surface temperature more easily and lower transfer energy for LDI MS; (4) CDs could serve as a matrix additive to suppress 9AA ionization. Furthermore, this matrix was allowed for the analysis of glucose as well as nucleosides in human urine, and the level of cytidine was quantified with a linear range of 0.05-5 mM (R(2) > 0.99). Therefore, the 9AA/CDs matrix was proven to be an effective MALDI matrix for the analysis of small molecules with improved sensitivity and reproducibility. This work provides an alternative solution for small molecules detection that can be further used in complex samples analysis. Graphical Abstract ᅟ. PMID:27075876

  12. Carbon Dots and 9AA as a Binary Matrix for the Detection of Small Molecules by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Chen, Yongli; Gao, Dan; Bai, Hangrui; Liu, Hongxia; Lin, Shuo; Jiang, Yuyang

    2016-04-01

    Application of matrix-assisted laser-desorption/ionization mass spectrometry (MALDI MS) to analyze small molecules have some limitations, due to the inhomogeneous analyte/matrix co-crystallization and interference of matrix-related peaks in low m/z region. In this work, carbon dots (CDs) were for the first time applied as a binary matrix with 9-Aminoacridine (9AA) in MALDI MS for small molecules analysis. By 9AA/CDs assisted desorption/ionization (D/I) process, a wide range of small molecules, including nucleosides, amino acids, oligosaccharides, peptides, and anticancer drugs with a higher sensitivity were demonstrated in the positive ion mode. A detection limit down to 5 fmol was achieved for cytidine. 9AA/CDs matrix also exhibited excellent reproducibility compared with 9AA matrix. Moreover, by exploring the ionization mechanism of the matrix, the influence factors might be attributed to the four parts: (1) the strong UV absorption of 9AA/CDs due to their π-conjugated network; (2) the carboxyl groups modified on the CDs surface act as protonation sites for proton transfer in positive ion mode; (3) the thin layer crystal of 9AA/CDs could reach a high surface temperature more easily and lower transfer energy for LDI MS; (4) CDs could serve as a matrix additive to suppress 9AA ionization. Furthermore, this matrix was allowed for the analysis of glucose as well as nucleosides in human urine, and the level of cytidine was quantified with a linear range of 0.05-5 mM (R2 > 0.99). Therefore, the 9AA/CDs matrix was proven to be an effective MALDI matrix for the analysis of small molecules with improved sensitivity and reproducibility. This work provides an alternative solution for small molecules detection that can be further used in complex samples analysis.

  13. Docosahexaenoic acid supplementation fully restores fertility and spermatogenesis in male delta-6 desaturase-null mice

    PubMed Central

    Roqueta-Rivera, Manuel; Stroud, Chad K.; Haschek, Wanda M.; Akare, Sandeep J.; Segre, Mariangela; Brush, Richard S.; Agbaga, Martin-Paul; Anderson, Robert E.; Hess, Rex A.; Nakamura, Manabu T.

    2010-01-01

    Delta-6 desaturase-null mice (−/−) are unable to synthesize highly unsaturated fatty acids (HUFAs): arachidonic acid (AA), docosahexaenoic acid (DHA), and n6-docosapentaenoic acid (DPAn6). The −/− males exhibit infertility and arrest of spermatogenesis at late spermiogenesis. To determine which HUFA is essential for spermiogenesis, a diet supplemented with either 0.2% (w/w) AA or DHA was fed to wild-type (+/+) and −/− males at weaning until 16 weeks of age (n = 3–5). A breeding success rate of DHA-supplemented −/− was comparable to +/+. DHA-fed −/− showed normal sperm counts and spermiogenesis. Dietary AA was less effective in restoring fertility, sperm count, and spermiogenesis than DHA. Testis fatty acid analysis showed restored DHA in DHA-fed −/−, but DPAn6 remained depleted. In AA-fed −/−, AA was restored at the +/+ level, and 22:4n6, an AA elongated product, accumulated in testis. Cholesta-3,5-diene was present in testis of +/+ and DHA-fed −/−, whereas it diminished in −/− and AA-fed −/−, suggesting impaired sterol metabolism in these groups. Expression of spermiogenesis marker genes was largely normal in all groups. In conclusion, DHA was capable of restoring all observed impairment in male reproduction, whereas 22:4n6 formed from dietary AA may act as an inferior substitute for DHA. PMID:19690334

  14. A human dietary arachidonic acid supplementation study conducted in a metabolic research unit: rationale and design.

    PubMed

    Nelson, G J; Kelley, D S; Emken, E A; Phinney, S D; Kyle, D; Ferretti, A

    1997-04-01

    While there are many reports of studies that fed arachidonic acid (AA) to animals, there are very few reports of AA feeding to humans under controlled conditions. This 130-d study was conceived as a controlled, symmetrical crossover design with healthy, adult male volunteers. They lived in the metabolic research unit (MRU) of the Western Human Nutrition Research (WHNRC) for the entire study. All food was prepared by the WHNRC kitchen. The basal (low-AA) diet consisted of natural foods (30 en% fat, 15 en% protein, and 55 en% carbohydrate), containing 210 mg/d of AA, and met the recommended daily allowance for all nutrients. The high-AA (intervention) diet was similar except that 1.5 g/d of AA in the form of a triglyceride containing 50% AA replaced an equal amount of high-oleic safflower oil in the basal diet. The subjects (ages 20 to 39) were within -10 to +20% of ideal body weight, nonsmoking, and not allowed alcohol in the MRU. Their exercise level was constant, and their body weights were maintained within 2% of entry level. Subjects were initially fed the low-AA diet for 15 d. On day 16, half of the subjects (group A) wee placed on the high-AA diet, and the other group (B) remained on the low-AA diets. On day 65, the two groups switched diets. On day 115, group B returned to the low-AA diet. This design, assuming no carryover effect, allowed us to merge the data from the two groups, with the data comparison days being 65 (low-AA) and 115 (high-AA) for group B and 130 (low-AA) and 65 (high-AA) for group A. The main indices studied were the fatty acid composition of the plasma, red blood cells, platelets, and adipose tissue; in vitro platelet aggregation, bleeding times, clotting factors; immune response as measured by delayed hypersensitivity skin tests, cellular proliferation of peripheral blood mononuclear cells in response to various mitogens and antigens, natural killer cell activity, and response to measles/mumps/rubella and influenza vaccines; the

  15. Energy flow along the medium-induced parton cascade

    NASA Astrophysics Data System (ADS)

    Blaizot, J.-P.; Mehtar-Tani, Y.

    2016-05-01

    We discuss the dynamics of parton cascades that develop in dense QCD matter, and contrast their properties with those of similar cascades of gluon radiation in vacuum. We argue that such cascades belong to two distinct classes that are characterized respectively by an increasing or a constant (or decreasing) branching rate along the cascade. In the former class, of which the BDMPS, medium-induced, cascade constitutes a typical example, it takes a finite time to transport a finite amount of energy to very soft quanta, while this time is essentially infinite in the latter case, to which the DGLAP cascade belongs. The medium induced cascade is accompanied by a constant flow of energy towards arbitrary soft modes, leading eventually to the accumulation of the initial energy of the leading particle at zero energy. It also exhibits scaling properties akin to wave turbulence. These properties do not show up in the cascade that develops in vacuum. There, the energy accumulates in the spectrum at smaller and smaller energy as the cascade develops, but the energy never flows all the way down to zero energy. Our analysis suggests that the way the energy is shared among the offsprings of a splitting gluon has little impact on the qualitative properties of the cascades, provided the kernel that governs the splittings is not too singular.

  16. Antibody conjugates with unnatural amino acids.

    PubMed

    Hallam, Trevor J; Wold, Erik; Wahl, Alan; Smider, Vaughn V

    2015-06-01

    Antibody conjugates are important in many areas of medicine and biological research, and antibody-drug conjugates (ADCs) are becoming an important next generation class of therapeutics for cancer treatment. Early conjugation technologies relied upon random conjugation to multiple amino acid side chains, resulting in heterogeneous mixtures of labeled antibody. Recent studies, however, strongly support the notion that site-specific conjugation produces a homogeneous population of antibody conjugates with improved pharmacologic properties over randomly coupled molecules. Genetically incorporated unnatural amino acids (uAAs) allow unique orthogonal coupling strategies compared to those used for the 20 naturally occurring amino acids. Thus, uAAs provide a novel paradigm for creation of next generation ADCs. Additionally, uAA-based site-specific conjugation could also empower creation of additional multifunctional conjugates important as biopharmaceuticals, diagnostics, or reagents. PMID:25898256

  17. Effects of arachidonic acid on ATP-sensitive K+ current in murine colonic smooth muscle cells.

    PubMed

    Jun, Jae Yeoul; Yeum, Cheol Ho; Park, Yoo Whan; Jang, In Youb; Kong, In Deok; Sim, Jae Hoon; So, Insuk; Kim, Ki Whan; You, Ho Jin

    2002-09-01

    The effects of arachidonic acid (AA) and the mechanism through which it modulates ATP-sensitive K+ (K(ATP)) currents were examined in single smooth muscle cells of murine proximal colon. In the current-clamping mode, AA and glibenclamide induced depolarization of membrane potential. Using 0.1 mM ATP and 140 mM K+ solution in the pipette and 90 mM K+ in the bath solution at a -80 mV of holding potential, pinacidil activated the glibenclamide-sensitive inward current. The potential of these currents was reversed to near the equilibrium potential of K+ by 60 mM K+ in the bath solution. AA inhibited K(ATP) currents in a dose-dependent manner. This inhibition was not changed when 1 mM GDPbetaS was present in the pipette. Chelerythrine, protein kinase C inhibitor, did not block the AA effects. Superoxide dismutase and metabolic inhibitors (indomethacin and nordihydroguaiacretic acid) of AA did not affect the AA-induced inhibition. Eicosatetraynoic acid, a nonmetabolizable analogue of AA, inhibited the K(ATP) currents. These results suggest that AA-induced inhibition of K(ATP) currents is not mediated by G-protein or protein kinase C activation. The inhibitory action is likely to be a possible mechanism of AA-induced membrane depolarization. PMID:12396031

  18. Functional amino acids in fish nutrition, health and welfare.

    PubMed

    Andersen, Synne M; Waagbø, Rune; Espe, Marit

    2016-01-01

    Protein is the most expensive part of fish diets and supplies amino acids (AA) for energy, growth, protein synthesis and as substrates for key metabolic pathways. Functional AA is a term used to describe AA that are involved in cellular processes apart from protein synthesis. A deficiency, or imbalance, in functional AA may impair body metabolism and homeostasis. Recent years have seen an increased interest in AA to increase disease resistance, immune response, reproduction, behavior and more. This has led to a boost of commercially available functional fish feeds that aim to optimize fish performance and quality of the product. This review aim to collect recent findings of functional AA and of how they may improve fish health and welfare. It will focus on functional properties of some of the most studied AA, namely arginine, glutamine, glutamate, tryptophan, sulfur amino acids (methionine, cysteine and taurine), histidine and branched chain amino acids. Where information is not available in fish, we will point towards functions known in animals and humans, with possible translational functions to fish. PMID:26709652

  19. Structural Basis of Fatty Acid Substrate Binding to Cyclooxygenase-2*

    PubMed Central

    Vecchio, Alex J.; Simmons, Danielle M.; Malkowski, Michael G.

    2010-01-01

    The cyclooxygenases (COX-1 and COX-2) are membrane-associated heme-containing homodimers that generate prostaglandin H2 from arachidonic acid (AA). Although AA is the preferred substrate, other fatty acids are oxygenated by these enzymes with varying efficiencies. We determined the crystal structures of AA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) bound to Co3+-protoporphyrin IX-reconstituted murine COX-2 to 2.1, 2.4, and 2.65 Å, respectively. AA, EPA, and docosahexaenoic acid bind in different conformations in each monomer constituting the homodimer in their respective structures such that one monomer exhibits nonproductive binding and the other productive binding of the substrate in the cyclooxygenase channel. The interactions identified between protein and substrate when bound to COX-1 are conserved in our COX-2 structures, with the only notable difference being the lack of interaction of the carboxylate of AA and EPA with the side chain of Arg-120. Leu-531 exhibits a different side chain conformation when the nonproductive and productive binding modes of AA are compared. Unlike COX-1, mutating this residue to Ala, Phe, Pro, or Thr did not result in a significant loss of activity or substrate binding affinity. Determination of the L531F:AA crystal structure resulted in AA binding in the same global conformation in each monomer. We speculate that the mobility of the Leu-531 side chain increases the volume available at the opening of the cyclooxygenase channel and contributes to the observed ability of COX-2 to oxygenate a broad spectrum of fatty acid and fatty ester substrates. PMID:20463020

  20. Allometric scaling of dietary linoleic acid on changes in tissue arachidonic acid using human equivalent diets in mice

    PubMed Central

    2011-01-01

    Background It is hypothesized that dietary linoleic acid (LA) promotes chronic and acute diseases in humans by enriching tissues with arachidonic acid (AA), its downstream metabolite, and dietary studies with rodents have been useful for validation. However, levels of LA in research diets of rodents, as published in the literature, are notoriously erratic making interspecies comparisons unreliable. Therefore, the ability to extrapolate the biological effects of dietary LA from experimental rodents to humans necessitates an allometric scaling model that is rooted within a human equivalent context. Methods To determine the physiological response of dietary LA on tissue AA, a mathematical model for extrapolating nutrients based on energy was used, as opposed to differences in body weight. C57BL/6J mice were divided into 9 groups fed a background diet equivalent to that of the US diet (% energy) with supplemental doses of LA or AA. Changes in the phospholipid fatty acid compositions were monitored in plasma and erythrocytes and compared to data from humans supplemented with equivalent doses of LA or AA. Results Increasing dietary LA had little effect on tissue AA, while supplementing diets with AA significantly increased tissue AA levels, importantly recapitulating results from human trials. Conclusions Thus, interspecies comparisons for dietary LA between rodents and humans can be achieved when rodents are provided human equivalent doses based on differences in metabolic activity as defined by energy consumption. PMID:21702942

  1. Simultaneous voltammetric determination for DA, AA and NO₂⁻ based on graphene/poly-cyclodextrin/MWCNTs nanocomposite platform.

    PubMed

    Zhang, Yu; Yuan, Ruo; Chai, Yaqin; Li, Wenjuan; Zhong, Xia; Zhong, Huaan

    2011-05-15

    In the present work, graphene sheets (GS) and multiwall carbon nanotubes (MWCNTs) were dispersed in the mixed solution of cyclodextrin (CD) and cyclodextrin prepolymer (pre-CD) and were used as modifier to fabricate chemical modified electrode to simultaneous detect dopamine (DA), ascorbic acid (AA) and nitrite (NO2(-)). CD cross-linked pre-CD (CDP) displays excellent film forming ability, which made the electrode stable. Comparing with CDP-GS, CDP-MWCNTs and CDP-GS-MWCNTs modified electrodes, the CDP-GS-MWCNTs displays higher catalytic activity and selectivity toward the oxidation of DA, AA and NO2(-), revealing that MWCNTs effectively inhibited the stacking of individual GS and enhanced the utilization of GS based composites. The host-guest chemical reaction ability of CD and π-π stacking interaction between detected molecules and GS-MWCNTs surface were considered as the main reasons of the successfully simultaneous detection of DA, AA and NO2(-). Cyclic voltammetry (CV), scanning electron microscopy (SEM) and different pulse voltammetry (DPV) were employed to characterize the biosensor. The linear response range for AA, DA and NO2(-) were 5 μM-0.48 mM, 0.15-21.65 μM and 5 μM-6.75 mM, respectively and the detection limits were 1.65 μM, 0.05 μM and 1.65 μM. PMID:21497078

  2. Molecular Characteristic, Protein Distribution and Potential Regulation of HSP90AA1 in the Anadromous Fish Coilia nasus

    PubMed Central

    Fang, Di-An; Duan, Jin-Rong; Zhou, Yan-Feng; Zhang, Min-Ying; Xu, Dong-Po; Liu, Kai; Xu, Pao

    2016-01-01

    Heat shock proteins play essential roles in basic cellular events. Spawning migration is a complex process, with significant structural and biochemical changes taking place in the adult gonad. To date, the molecular mechanisms underlying migration reproductive biology remain undetermined. In this regard, a full length HSP90AA1 comprising 2608 nucleotides from the anadromous fish Coilia nasus was characterized, encoding 742 amino acid (aa) residues with potential phosphorylation sites. HSP90AA1 mRNA transcripts were detected in all organs, especially in the gonad. Furthermore, the greatest transcript levels were found during the developmental phase, while the lowest levels were found during the resting phase. In addition, the strongest immunolabeling positive signal was found in the primary spermatocyte and oocyte, with lower positive staining in secondary germ cells, and a weak or absent level in the mature sperm and oocyte. Interestingly, HSP90AA1 was mainly located in the cytoplasm of germ cells. These results are important for understanding the molecular mechanism of anadromous migration reproductive biology. In combination with data from other fish species, the result of this present study may facilitate further investigations on the spawning migration mechanism. PMID:26828521

  3. Localization of the adenovirus E1Aa protein, a positive-acting transcriptional factor, in infected cells infected cells.

    PubMed Central

    Feldman, L T; Nevins, J R

    1983-01-01

    The function of the adenovirus E1Aa protein (the product of the 13S E1A mRNA) during a productive viral infection is to activate transcription of the six early viral transcription units. To study the mechanism of action of this protein, a peptide which was 13 amino acids long and had a sequence unique to the protein product of the adenovirus 13S E1A mRNA (pE1Aa) was coupled to keyhole limpet hemocyanin and used to raise an antibody in rabbits. The resulting antiserum was specific to this protein and did not react with the protein product of the 12S E1A mRNA, which shares considerable sequence with the E1Aa protein. This antiserum was used to probe for the E1Aa protein in situ by indirect immunofluorescence and in extracts of infected HeLa cells. We found that the protein was associated with large cellular structures both in the nucleus and in the cytoplasm. The nuclear form of the protein was analyzed further and was found to purify with the nuclear matrix. Images PMID:6346057

  4. Nephrotic Syndrome Associated with Lung Cancer: A Rare Case of Malignancy Associated with AA Amyloidosis

    PubMed Central

    Gueutin, Victor; Langlois, Anne-Lyse; Shehwaro, Nathalie; Elharraqui, Ryme; Rouvier, Philippe; Izzedine, Hassane

    2013-01-01

    Nonhematologic malignancies are rarely reported to be associated with AA amyloidosis. Although the association between renal cell carcinoma and systemic AA amyloidosis has been established, the evidence linking pulmonary cancer to AA amyloidosis is scarce. Here, a case of biopsy-proven renal AA amyloidosis complicated with nephrotic syndrome associated with lung carcinoma is reported. PMID:24558629

  5. Triggering cascades and statistical properties of aftershocks

    NASA Astrophysics Data System (ADS)

    Gu, C.; Davidsen, J.

    2011-12-01

    Applying a recently introduced general statistical procedure for identifying aftershocks based on complex network theory, we investigate the statistical properties of aftershocks for a high-resolution earthquake catalog covering Southern California. In comparison with earlier studies of aftershock sequences, we show that many features depend sensitively on how one defines aftershocks and whether one includes only first-generation of aftershocks or one also takes all indirectly triggered aftershocks into account. This includes the temporal variation in the rate of aftershocks for mainshocks of small magnitude, for example, as well as the variation in the rate of aftershocks for short to intermediate times after a mainshock. Other features are, however, robust indicating that they truly characterize aftershock sequences. These include the p-values in the Omori-Utsu law for large mainshocks, B{aa}th's law and the productivity law with an exponent smaller than the b-value in the Gutenberg-Richter law. We also find that, for large mainshocks, the dependence of the parameters in the Omori-Utsu law on the lower magnitude cut-off are in excellent agreement with a recent proposition based on B{aa}th's law and the Gutenberg-Richter law, giving rise to a generalized Omori-Utsu law. Our analysis also provides evidence that the exponent p in the Omori-Utsu law does not vary significantly with mainshock magnitude.

  6. The current disequilibrium of North Cascade glaciers

    NASA Astrophysics Data System (ADS)

    Pelto, Mauri S.

    2006-03-01

    Three lines of evidence indicate that North Cascade (Washington, USA) glaciers are currently in a state of disequilibrium. First, annual balance measured on nine glaciers yields a mean cumulative balance for the 1984-2004 period of -8.58 m water equivalent (w.e.), a net loss of ice thickness exceeding 9.5 m. This is a significant loss for glaciers that average 30-50 m in thickness, representing 18-32% of their entire volume.Second, longitudinal profiles completed in 1984 and 2002 on 12 North Cascade glaciers confirm this volume change indicating a loss of -5.7 to -6.3 m in thickness (5.0-5.6 m w.e.) between 1984 and 2002, agreeing well with the measured cumulative balance of -5.52 m w.e. for the same period. The change in thickness on several glaciers has been equally substantial in the accumulation zone and the ablation zone, indicating that there is no point to which the glacier can retreat to achieve equilibrium. Substantial thinning along the entire length of a glacier is the key indicator that a glacier is in disequilibrium.Third, North Cascade glacier retreat is rapid and ubiquitous. All 47 glaciers monitored are currently undergoing significant retreat or, in the case of four, have disappeared. Two of the glaciers where mass balance observations were begun, Spider Glacier and Lewis Glacier, have disappeared. The retreat since 1984 of eight Mount Baker glaciers that were all advancing in 1975 has averaged 297 m. These observations indicate broad regional continuity in glacial response to climate.

  7. Heat cascading regenerative sorption heat pump

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1995-01-01

    A simple heat cascading regenerative sorption heat pump process with rejected or waste heat from a higher temperature chemisorption circuit (HTCC) powering a lower temperature physisorption circuit (LTPC) which provides a 30% total improvement over simple regenerative physisorption compression heat pumps when ammonia is both the chemisorbate and physisorbate, and a total improvement of 50% or more for LTPC having two pressure stages. The HTCC contains ammonia and a chemisorbent therefor contained in a plurality of canisters, a condenser-evaporator-radiator system, and a heater, operatively connected together. The LTPC contains ammonia and a physisorbent therefor contained in a plurality of compressors, a condenser-evaporator-radiator system, operatively connected together. A closed heat transfer circuit (CHTC) is provided which contains a flowing heat transfer liquid (FHTL) in thermal communication with each canister and each compressor for cascading heat from the HTCC to the LTPC. Heat is regenerated within the LTPC by transferring heat from one compressor to another. In one embodiment the regeneration is performed by another CHTC containing another FHTL in thermal communication with each compressor. In another embodiment the HTCC powers a lower temperature ammonia water absorption circuit (LTAWAC) which contains a generator-absorber system containing the absorbent, and a condenser-evaporator-radiator system, operatively connected together. The absorbent is water or an absorbent aqueous solution. A CHTC is provided which contains a FHTL in thermal communication with the generator for cascading heat from the HTCC to the LTAWAC. Heat is regenerated within the LTAWAC by transferring heat from the generator to the absorber. The chemical composition of the chemisorbent is different than the chemical composition of the physisorbent, and the absorbent. The chemical composition of the FHTL is different than the chemisorbent, the physisorbent, the absorbent, and ammonia.

  8. Effects of ascorbic acid supplementation on male reproductive system during exposure to hypoxia

    NASA Astrophysics Data System (ADS)

    Havazhagan, G.; Riar, S. S.; Kain, A. K.; Bardhan, Jaya; Thomas, Pauline

    1989-09-01

    Two groups of male rats were exposed to simulated altitudes of 6060 m and 7576 m for 6 h/day for 7 days (intermittent exposure). In two additional groups of animals exposed to the same altitude, 100 mg of ascorbic acid (AA) was fed daily for 5 days prior to the exposure period and also during the exposure period. Rats that did not receive AA showed loss of body weight and weight of reproductive organs after exposure. Sex organs showed atrophy on histological examination and there was a deterioration in spermatozoal quality. There was an increase in alkaline and acid phosphatase, and decrease in protein, sialic acid and glyceryl phosphorylcholine content in various reproductive tissues after exposure. All the above changes in histology and biochemical composition could be partially prevented by AA supplementation. AA supplementation can therefore protect the male reproductive system from deleterious effects of hypoxia. The probable mechanism of action of AA is discussed.

  9. Section BB, Section DD, Plan AA, Plan CC, Typical Framing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Section B-B, Section D-D, Plan A-A, Plan C-C, Typical Framing Detail of Upper Stringers, Typical Framing Detail of Lower Stringers - Covered Bridge, Spanning Connecticut River, Orford, Grafton County, NH

  10. Stopping pions in high-energy nuclear cascades.

    NASA Technical Reports Server (NTRS)

    Jones, W. V.; Johnson, D. P.; Thompson, J. A.

    1973-01-01

    Results of Monte Carlo calculations for the number and energy spectra of charged pions from nuclear-electromagnetic cascades developing in rock are presented for primary hadron energies ranging from 3 to 3000 GeV. These spectra are given as functions of the longitudinal depth in the absorber and the lateral distance from the cascade axis. The number of charged pions which stop in the absorber increases with the primary energy of the hadron initiating the cascade.

  11. Spin Glass Computations and Ruelle's Probability Cascades

    NASA Astrophysics Data System (ADS)

    Arguin, Louis-Pierre

    2007-03-01

    We study the Parisi functional, appearing in the Parisi formula for the pressure of the SK model, as a functional on Ruelle's Probability Cascades (RPC). Computation techniques for the RPC formulation of the functional are developed. They are used to derive continuity and monotonicity properties of the functional retrieving a theorem of Guerra. We also detail the connection between the Aizenman-Sims-Starr variational principle and the Parisi formula. As a final application of the techniques, we rederive the Almeida-Thouless line in the spirit of Toninelli but relying on the RPC structure.

  12. Kelvin waves cascade in superfluid turbulence.

    PubMed

    Kivotides, D; Vassilicos, J C; Samuels, D C; Barenghi, C F

    2001-04-01

    We study numerically the interaction of four initial superfluid vortex rings in the absence of any dissipation or friction. We find evidence for a cascade of Kelvin waves generated by individual vortex reconnection events which transfers energy to higher and higher wave numbers k. After the vortex reconnections occur, the energy spectrum scales as k(-1) and the curvature spectrum becomes flat. These effects highlight the importance of Kelvin waves and reconnections in the transfer of energy within a turbulent vortex tangle. PMID:11290112

  13. Atomistic Simulation of Displacement Cascades in Zircon

    SciTech Connect

    Devanathan, Ram; Weber, William J.; Corrales, Louis R.; BP McGrail and GA Cragnolino

    2002-05-06

    Low energy displacement cascades in zircon (ZrSiO4) initiated by a Zr primary knock-on atom have been investigated by molecular dynamics simulations using a Coulombic model for long-range interactions, Buckingham potential for short-range interactions and Ziegler-Biersack potentials for close pair interactions. Displacements were found to occur mainly in the O sublattice, and O replacements by a ring mechanism were predominant. Clusters containing Si interstitials bridged by O interstitials, vacancy clusters and anti-site defects were found to occur. This Si-O-Si bridging is considerable in quenched liquid ZrSiO4.

  14. Pair Cascades in Blazars and Radio Galaxies

    NASA Astrophysics Data System (ADS)

    Roustazadeh Sheikhyousefi, Parisa

    2012-05-01

    Recently some intermediate BL Lac objects (IBL), low frequency peak BL Lac objects (LBL) and flat spectrum radio quasars (FSRQs) were detected as very high energy gamma-ray sources (VHE; E > 100 GeV) by the Major Atmospheric Gamma-ray Imaging Cherenkov Telescope (MAGIC), the High Energy Stereoscopic System (H.E.S.S) and the Very Energetic Radiation Imaging Telescope Array System (VERITAS). These discoveries suggest that VHE gamma-rays may be produced in all types of active galactic nuclei (AGN) and that this is not only a common property of high frequency peaked BL Lac objects (HBL). The detection of the radio galaxies M87, Cen A and NGC 1275 supports this idea. In those AGN, VHE photons may interact with low energy photons from the broadline region (BLR), accretion disk around the black hole or thermal infrared photons form a dust torus by photon-photon pair production if the total center-of-momentum frame energy is above threshold to produce an electron-positron pair. These particles can produce new high energy photons by Compton up-scattering, and again these high energy photons can interact with soft photons to produce a pair of particles. This process will continue, leading to a shower (cascade) of particles and radiation. As the shower develops, it will expand laterally. This may explain the detection of the radio galaxies as VHE gamma-ray sources. The central part of my Ph.D. research work deals with the theoretical simulation of very high energy gamma-ray induced pair cascades in blazars and radio galaxies. Gamma-rays from the core of the AGN interact with low energy photons from the AGN environment and produce pairs of electrons and positrons resulting in Compton supported pair cascades. I developed a Monte Carlo code which treats the processes of gamma-gamma absorption and pair production, gamma-ray and electron/positron propagation, and Compton scattering, tracking particle trajectories in full 3-dimensional geometry. I showed that even for a very weak

  15. Cascaded proton acceleration by collisionless electrostatic shock

    SciTech Connect

    Xu, T. J.; Shen, B. F. E-mail: zhxm@siom.ac.cn; Zhang, X. M. E-mail: zhxm@siom.ac.cn; Yi, L. Q.; Wang, W. P.; Zhang, L. G.; Xu, J. C.; Zhao, X. Y.; Shi, Y.; Liu, C.; Pei, Z. K.

    2015-07-15

    A new scheme for proton acceleration by cascaded collisionless electrostatic shock (CES) is proposed. By irradiating a foil target with a moderate high-intensity laser beam, a stable CES field can be induced, which is employed as the accelerating field for the booster stage of proton acceleration. The mechanism is studied through simulations and theoretical analysis, showing that a 55 MeV seed proton beam can be further accelerated to 265 MeV while keeping a good energy spread. This scheme offers a feasible approach to produce proton beams with energy of hundreds of MeV by existing available high-intensity laser facilities.

  16. Free Energy Cascade in Gyrokinetic Turbulence

    SciTech Connect

    Banon Navarro, A.; Morel, P.; Albrecht-Marc, M.; Carati, D.; Merz, F.; Goerler, T.; Jenko, F.

    2011-02-04

    In gyrokinetic theory, the quadratic nonlinearity is known to play an important role in the dynamics by redistributing (in a conservative fashion) the free energy between the various active scales. In the present study, the free energy transfer is analyzed for the case of ion temperature gradient driven turbulence. It is shown that it shares many properties with the energy transfer in fluid turbulence. In particular, one finds a (strongly) local, forward (from large to small scales) cascade of free energy in the plane perpendicular to the background magnetic field. These findings shed light on some fundamental properties of plasma turbulence, and encourage the development of large-eddy-simulation techniques for gyrokinetics.

  17. Cascaded integrated waveguide linear microcavity filters

    NASA Astrophysics Data System (ADS)

    Pruessner, Marcel W.; Stievater, Todd H.; Goetz, Peter G.; Rabinovich, William S.; Urick, Vincent J.

    2013-07-01

    We experimentally demonstrate cascaded Fabry-Perot microcavity filters fabricated on silicon-on-insulator substrates. The cavities are formed by etching three sets of quarter-wavelength trenches along a rib waveguide, each set forming a Bragg reflector. Various configurations are examined with a view towards maximizing the filter extinction and minimizing the linewidth. We investigate the origin of spurious cavity modes and show how these are minimized. The effect of mode-splitting due to inter-cavity coupling is suppressed by increasing the reflectivity of the center mirror. Experimental results compare well with transfer matrix predictions.

  18. Cascades of Fano resonances in Mie scattering

    NASA Astrophysics Data System (ADS)

    Rybin, M. V.; Sinev, I. S.; Samusev, K. B.; Limonov, M. F.

    2014-03-01

    The interference nature of resonant Mie scattering, which is described within the Fano model, has been demonstrated. The interference is caused by interaction of an incident electromagnetic wave with reemitted waves that correspond to eigenmodes of a scattering particle. Mie scattering due to the interference can be represented in the form of cascades of resonance lines of different shapes, each of which is described by the classical Fano formula. The effect is observed in resonant light scattering by an arbitrary body of revolution and discussed in detail using the example of scattering by an infinite homogeneous dielectric cylinder.

  19. Atom localization with double-cascade configuration

    NASA Astrophysics Data System (ADS)

    Gordeev, Maksim Yu; Efremova, Ekaterina A.; Rozhdestvensky, Yuri V.

    2016-03-01

    We investigate the one-dimensional (1D) and two-dimensional (2D) atom localization of a four-level system in a double-cascade configuration. We demonstrate the possibility of 1D localization in the field of a standing wave, 2D localization in the field of two standing waves and 2D localization only in the field of running waves by using different configurations of driven waves on transitions. In addition, for each configuration we reached a high-precision atom localization in one of the states at scales much smaller than the wavelength of the incident optical radiation.

  20. Cascading Multicriticality in Nonrelativistic Spontaneous Symmetry Breaking

    NASA Astrophysics Data System (ADS)

    Griffin, Tom; Grosvenor, Kevin T.; Hořava, Petr; Yan, Ziqi

    2015-12-01

    Without Lorentz invariance, spontaneous global symmetry breaking can lead to multicritical Nambu-Goldstone modes with a higher-order low-energy dispersion ω ˜kn (n =2 ,3 ,… ), whose naturalness is protected by polynomial shift symmetries. Here, we investigate the role of infrared divergences and the nonrelativistic generalization of the Coleman-Hohenberg-Mermin-Wagner (CHMW) theorem. We find novel cascading phenomena with large hierarchies between the scales at which the value of n changes, leading to an evasion of the "no-go" consequences of the relativistic CHMW theorem.

  1. Photonic crystal slab quantum cascade detector

    SciTech Connect

    Reininger, Peter Schwarz, Benedikt; Harrer, Andreas; Zederbauer, Tobias; Detz, Hermann; Maxwell Andrews, Aaron; Gansch, Roman; Schrenk, Werner; Strasser, Gottfried

    2013-12-09

    In this Letter, we demonstrate the design, fabrication, and characterization of a photonic crystal slab quantum cascade detector (PCS-QCD). By employing a specifically designed resonant cavity, the performance of the photodetector is improved in three distinct ways. The PCS makes the QCD sensitive to surface normal incident light. It resonantly enhances the photon lifetime inside the active zone, thus increasing the photocurrent significantly. And, the construction form of the device inherently decreases the noise. Finally, we compare the characteristics of the PCS-QCD to a PCS - quantum well infrared photodetector and outline the advantages for certain fields of applications.

  2. Cascade impactor and jet plate for same

    DOEpatents

    Dahlin, Robert S.; Farthing, William E.; Landham Jr., Edward C.

    2004-02-03

    A sampling system and method for sampling particulate matter from a high-temperature, high-pressure gas stream. A cyclone sampler for use at high temperatures and pressures, and having threadless sacrificial connectors is disclosed. Also disclosed is an improved cascade impactor including jet plates with integral spacers, and alignment features provided for aligning the jet plates with their associated collection substrates. An activated bauxite alkali collector is disclosed, and includes an alumina liner. The sampling system can be operated remotely or locally, and can be permanently installed or configured as a portable system.

  3. External cavity coherent quantum cascade laser array

    NASA Astrophysics Data System (ADS)

    Vallon, Raphael; Parvitte, Bertrand; Bizet, Laurent; De Naurois, Guy Mael; Simozrag, Bouzid; Maisons, Grégory; Carras, Mathieu; Zeninari, Virginie

    2016-05-01

    We report on the development of a coherent quantum cascade laser array that consists in the fabrication of multi-stripes array. The main characteristic of this kind of source is that an anti-symmetrical signature with two lobes is obtained in the far field. Taking advantage of this drawback, a grating is aligned with one lobe of the source. Thus a Littrow configuration is designed that permit to obtain a wide tunability of the source. First results are presented and a preliminary test of the source is realized by measurements on acetone.

  4. Single-mode tapered quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Rauter, Patrick; Menzel, Stefan; Gokden, B.; K. Goyal, Anish; Wang, Christine A.; Sanchez, Antonio; Turner, George; Capasso, Federico

    2013-05-01

    We demonstrate tapered quantum cascade lasers monolithically integrated with a distributed Bragg reflector acting as both a wavelength-selective back mirror and a transverse mode filter. Each of the 14 devices operates at a different wavelength between 9.2 and 9.7 μm, where nine devices feature single-mode operation at peak powers between 0.3 and 1.6 W at room temperature. High output power and excellent beam quality with peak brightness values up to 1.6 MW cm-2 sr-1 render these two-terminal devices highly suitable for stand-off spectroscopy applications.

  5. The metal interconnected cascade solar cell

    SciTech Connect

    LaRue, R.A.; Borden, P.G.; Dietze, W.T.; Gregory, P.E.; Ludowise, M.J.

    1982-09-01

    A cascade cell employing a new type of interconnect is described. It uses a groove etch and metallization process to connect the base of the top cell to the emitter of the bottom cell. The best cell yielded 21.3% efficiency under conditions of AM3, 130 suns, 50/sup 0/C, with the result not corrected for grid coverage. Other features include a 1.2-micron thick 1.82-eV ALGaAs top cell with a BSF under the base and an n/p heteroface GaAs bottom cell that is stable during top cell growth.

  6. Cascaded Mach–Zehnder interferometer tunable filters

    NASA Astrophysics Data System (ADS)

    Ovvyan, A. P.; Gruhler, N.; Ferrari, S.; Pernice, W. H. P.

    2016-06-01

    By cascading compact and low-loss Mach–Zehnder interferometers (MZIs) embedded within nanophotonic circuits we realize thermo-optically tunable optical filters for the visible wavelength range. Through phase tuning in either arm of the MZI, the filter response with maximum extinction can be shifted beyond one free-spectral range with low electrical power consumption. The working wavelength of our device is aligned with the emission wavelength of the silicon vacancy color center in diamond around 740 nm where we realize a filter depth beyond 36.5 dB. Our approach allows for efficient isolation of the emitted signal intensity in future hybrid nanodiamond-nanophotonic circuits.

  7. Multiplicative cascades and seismicity in natural time

    SciTech Connect

    Sarlis, N. V.; Skordas, E. S.; Varotsos, P. A.

    2009-08-15

    Natural time chi enables the distinction of two origins of self-similarity, i.e., the process memory and the process increments infinite variance. Employing multiplicative cascades in natural time, the most probable value of the variance kappa{sub 1}(ident to-{sup 2}) is explicitly related with the parameter b of the Gutenberg-Richter law of randomly shuffled earthquake data. Moreover, the existence of temporal and magnitude correlations is studied in the original earthquake data. Magnitude correlations are larger for closer in time earthquakes, when the maximum interoccurrence time varies from half a day to 1 min.

  8. Brine rejection and cascades in the Arctic

    NASA Astrophysics Data System (ADS)

    Postlethwaite, C.; Luneva, M.

    2012-04-01

    The formation of sea ice is accompanied by brine rejection, where the ice releases much of its salt into the underlying water. This causes densification of the seawater which consequently sinks. On the continental shelf the dense plume may reach all the way to the sea bed. If the horizontal density gradient is sufficient, a dense water cascade can occur, transporting the brine down the continental slope and ultimately into the deep ocean. The fate of this brine is poorly represented in ocean models because (1) the coarse horizontal resolution does not capture the small scale over which brine release occurs and (2) the coarse vertical resolution cannot resolve the dense water cascades that transport the dense brine from the continental shelf into the deep ocean. This work focuses on exploring ways of altering the vertical grid of an ocean model in order to allow the transport of brine from the Arctic Shelf to Arctic Basin via dense cascades. We present results from a 7 km and 18km resolution pan-Arctic ocean/sea ice model (NEMO SHELF - LIM2). Idealised model experiments indicate that using a hybrid vertical grid enables the model to resolve dense water flows down and along the Arctic continental slope. The hybrid coordinates include stretching the vertical grid to align with the seabed topography in shallow shelf waters (sigma coordinates) and allowing it to be horizontal when the water depth is greater (z coordinates). It also involves limiting how steep the grid cells can slope when there is steep topography. A passive tracer that tracks the salt introduced to the ocean when ice forms and brine is rejected was included in the model. Initial pan-Arctic experiments using realistic forcing and initial conditions suggest that with the improved vertical grid the brine tracer crosses the shelf break but the locations where the tracer enters the deep Arctic Basin are limited. As the Arctic moves towards being seasonally ice covered, brine transport pathways are likely to

  9. AAS Committee on Employment Panel Introduction

    NASA Astrophysics Data System (ADS)

    Borne, Kirk; Fanelli, M. N.; Storrie-Lombardi, L. J.; Krishnamurthi, A.

    2006-12-01

    Many younger astronomers are unaware of the dangers and pitfalls that await them in the job market. Issues related to fringe benefits (if any), moving expenses, medical coverage for family members, teaching versus research expectations, etc. can lead to misunderstandings and to serious difficulties if these are not addressed early in the job interview process. The AAS Committee on Employment has often received letters from concerned junior members of the society, who feel that they needed more guidance and assistance in entering the job market for the first time. The major areas of concern have included those just listed, but there may be others. The session is structured as a panel presentation, whose members are asked to prepare in advance their top 10 questions that job applicants should ask, and we will instruct our panel members not to discuss their list at all with the other panel members prior to their presentations. This will ensure independent viewpoints and novel responses. The panel will consist of astronomers who have different perspectives on this issue, including old and young, postdoc and beyond, academic and non-academic. To kick off the session, we will invite a brief humorous presentation of the Top Ten List, in the style of The Night Show host David Letterman.

  10. Microstructure and properties of AA 2090 weldments

    SciTech Connect

    Sunwoo, A.J.; Morris, J.W. Jr.

    1988-06-01

    The effects of welding on AA 2090 are examined along with the metallurgical changes associated with welding and aging. The results of the study show that the GTA and EB weldment properties are controlled by the precipitate size and distribution. There is a trade-off between strength and elongation. In the as-welded condition, solid solution strengthening is the primary strengthening mechanism present. As a result, the weldment strengths are less than 200 MPa, but the elongations are greater than 4%. In the post-weld aged condition, an inhomogeneous distribution of solutes results in an inhomogeneous distribution of precipitates, causing strain localization. Although the weldment strengths increase, the weldment elongations decrease precipitously. The peak strengths of EB and GTA weldments are obtained aging at 160{degree}C for 32 hours with 75% joint efficiency and at 190{degree}C for 16 hours with 65% joint efficiency, respectively. Aging at 230{degree}C leads to coarsening of precipitates as well as the intermetallic constituents; the weldment strengths deteriorate rapidly, but the elongations improve. The best overall weldment properties are obtained in the solution heat treated and aged conditions, and are associated with a homogeneous distribution of strengthening precipitates. 13 refs.

  11. Recrystallization behaviour of AA6063 extrusions

    NASA Astrophysics Data System (ADS)

    Zhang, K.; Pettersen, T.; Paulsen, C. O.; Marthinsen, K.; Holmedal, B.; Segatori, A.

    2015-08-01

    Cylindrical profiles of an AA6063 aluminium alloy were produced in a lab-scale direct extrusion set-up. The extrusion was performed at 300 °C, 450 °C and 550 °C, respectively, with the same ram speed. Immediate water quenching was applied to the profiles and the end of billet (butt-end) after extrusion. Microstructure and texture of the material in different states were measured by electron back-scattered diffraction. Only the profile extruded at 300 °C, was found in the deformed state after extrusion, featuring a fibrous grain structure and a strong <111> and weak <100> double fibre texture. Post-extrusion annealing of this profile at 450 °C resulted in an almost fully recrystallized structure (recrystallized fraction of 87%) and with a texture similar to that of the as-deformed state. The profile extruded at 450 °C was almost fully recrystallized (recrystallization fraction 91%) already after quenching, and with a texture characterized by a weak <111> and strong <100> double fibre. The profile extruded at 550 °C showed a partially recrystallized grain structure with recrystallization fraction of 71%, and with a texture dominated by a <100> fibre. The influence of the deformation conditions on the recrystallization behaviour, in terms of recrystallization kinetics and mechanisms, are discussed in view of these results.

  12. Cascade Synthesis of Five-Membered Lactones using Biomass-Derived Sugars as Carbon Nucleophiles.

    PubMed

    Yamaguchi, Sho; Matsuo, Takeaki; Motokura, Ken; Miyaji, Akimitsu; Baba, Toshihide

    2016-06-01

    We report the cascade synthesis of five-membered lactones from a biomass-derived triose sugar, 1,3-dihydroxyacetone, and various aldehydes. This achievement provides a new synthetic strategy to generate a wide range of valuable compounds from a single biomass-derived sugar. Among several examined Lewis acid catalysts, homogeneous tin chloride catalysts exhibited the best performance to form carbon-carbon bonds. The scope and limitations of the synthesis of five-membered lactones using aldehyde compounds are investigated. The cascade reaction led to high product selectivity as well as diastereoselectivity, and the mechanism leading to the diastereoselectivity was discussed based on isomerization experiments and density functional theory (DFT) calculations. The present results are expected to support new approaches for the efficient utilization of biomass-derived sugars. PMID:27061111

  13. Outcomes From AAS Hack Day at the 227th AAS Meeting

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Editors Note:This is a final post from the 227th AAS Meeting in Kissimmee, FL. This special summary of AAS Hack Day, a meeting of AAS members to collaboratively work on various small projects, was written by Meredith Rawls (@Merrdiff) and was originally posted on astrobites.com.As the 227thAmerican Astronomical Society meeting drew to a close (see highlights from Day 1, Day 2, Day 3, and Day 4), a group of at least 50 attendees spent Day 4working on small projects fondly called hacks. Thanks to sponsorship from LSST and Northrup Grumman, the industrious hackers werewell-caffeinated and fed so we could devote time and energy toworking in groups on one-day projects.TheHack Day beganat 10am with pitches. Anybody with a project idea was welcome to briefly speak and try to convince others to work with them. Only someideas panned out, but the enthusiasm was palpable. Its not every day you get a full room of astronomers and affiliates eager to spend hours working on fun and useful projects to benefit the community.#hackAAS is getting underway! #aas227 pic.twitter.com/yX7jlOnSCK James R A Davenport (@jradavenport) January 8, 2016Here is a rundown of what we accomplished. Pretty impressive for a single day! Many thanks to fellow astrobiter Erika Nesvold (now at Carnegie DTM; @erikanesvold) whose hack was live-documenting all the other hacks. Her tweets as @astrobites appeared with the #hackaas hashtag, and her notes made this recap post infinitely easier to write.Interested in joining the fun? Sign up for Hack Day at the 2017 JanuaryAAS meeting (its free with meeting registration), and consider applying for the .Astronomy conference this summer.Towards Optimal Session Scheduling:Adrian Price-Whelan (Columbia), David Hogg (NYU), and Scott Idem (AAS) began writing a program to take all submitted abstracts to a conference like AAS and sort them using keywords to avoid scheduling similar talks in parallel sessions. Its impossible to make everyone happy, but minimizing conflicts

  14. Asiago spectroscopic classification of SN2016aa in PGC 22658

    NASA Astrophysics Data System (ADS)

    Ciabattari, F.; Tomasella, L.; Pastorello, A.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Ochner, P.; Tartaglia, L.; Terreran, G.; Turatto, M.; Briganti, F.; Caimmi, M.; Campaner, P.; Donati, S.; Mazzoni, E.

    2016-02-01

    We report the spectroscopic classification of SN2016aa in PGC 22658 through observations obtained with the 1.82-m Copernico Telescope in Asiago (+ AFOSC; range 340-820 nm, resolution 1.3 nm). A low signal-to-noise spectrogram obtained on Jan 04.97 UT indicates that SN2016aa is a Type II SNe, a few weeks after the explosion.

  15. Section AA through main entrance gates & west stairs. San ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Section AA through main entrance gates & west stairs. San Bernardino Valley Union Junior College, Science Building. Also includes plans and sections of boys' and girls' toilets. Howard E. Jones, Architect, San Bernardino, California. Sheet 5, job no. 311. Scales 1/4 inch to the foot (section AA) and 1/2 inch to the foot (toilet rooms). February 15, 1927. - San Bernardino Valley College, Life Science Building, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

  16. Boise Cascade Mill Energy Assessment (Boise Cascade Mill, International Falls, MN)

    SciTech Connect

    2000-12-01

    An integrated effluent heat reduction and water conservation study was performed at the Boise Cascade plant in International Falls, MN. The implementation of 4 projects and 2 process modifications are projected to remove 45.6 Btu/hr from the effluent.

  17. The comparison of extraction of energy in two-cascade and one-cascade targets

    NASA Astrophysics Data System (ADS)

    Dolgoleva, G. V.; Ponomarev, I. V.

    2016-01-01

    The paper is devoted to numerical designing of cylindrical microtargets on the basis of shock-free compression. When designing microtargets for the controlled thermonuclear fusion, the core tasks are to select geometry and make-up of layers, and the law of energy embedding as well, which allow receiving of "burning" of deuterium- tritium mix, that is, the existence of thermonuclear reactions of working area. Yet, the energy yield as a result of thermonuclear reactions has to be more than the embedded energy (the coefficient of amplification is more than a unit). So, an important issue is the value of the embedded energy. The purpose of the present paper is to study the extraction of energy by working DT area in one-cascade and two-cascade targets. A bigger extraction of energy will contribute to a better burning of DT mix and a bigger energy yield as a result of thermonuclear reactions. The comparison of analytical results to numerical calculations is carried out. The received results show advantages of a two-cascade target compared to a one-cascade one.

  18. Computer modeling results on all-Si cascade solar cells

    NASA Technical Reports Server (NTRS)

    Sparks, P. D.; Allen, F. G.; Daud, T.

    1984-01-01

    The properties of a cascade solar cell made entirely of silicon are investigated numerically with the goal of developing an optimal silicon solar cell grown by molecular-beam epitaxy. The cascade cell is modeled as two standard back-surface field cells with abrupt junctions connected by a tunnel junction. A cascade cell would have approximately twice the open-circuit voltage of a single cell. If the minority carriers generated in the front cell can be reflected before reaching the tunnel junction, then the cascade cell will show an increase in efficiency over a single cell by a percentage point.

  19. Applications of TIERRAS for underground particle cascade simulations

    SciTech Connect

    Tueros, M. J.

    2010-11-24

    In this communication we present some example applications of TIERRAS, a software package for the simulation of High Energy particle cascades underground and underwater. The examples illustrate how this package can be used to study the phenomenology of particle cascades from Extended Air Showers propagated several meters underground, including the effect of the surface ''albedo'' particles that are generated when a cascade reaches ground level. These up-going particles can have a measurable effect on surface or shallow underground detectors. Finally, to show the package ability ro perform simulations of particle cascades in ice, an application for neutrino radio detection is briefly introduced.

  20. Cascaded Gamma Rays as a Probe of Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Murase, Kohta

    2014-06-01

    Very-high-energy (VHE) and ultra-high-energy (UHE) gamma rays from extragalactic sources experience electromagnetic cascades during their propagation in intergalactic space. Recent gamma-ray data on TeV blazars and the diffuse gamma-ray background may have hints of the cascade emission, which are especially interesting if it comes from UHE cosmic rays. I show that cosmic-ray-induced cascades can be discriminated from gamma-ray-induced cascades with detailed gamma-ray spectra. I also discuss roles of structured magnetic fields, which suppress inverse-Compton pair halos/echoes but lead to guaranteed signals - synchrotron pair halos/echoes.

  1. Large-scale separation and hysteresis in cascades

    NASA Technical Reports Server (NTRS)

    Rothmayer, A. P.; Smith, F. T.

    1985-01-01

    An approach using a two-dimensional thin aerofoil, allied with the theory of viscous bluff-body separation, is used to study the initial cross-over from massive separation to an attached flow in a single-row unstaggered cascade. Analytic solutions are developed for the limit of small cascade-spacing. From the analytic solutions several interesting features of the cascade are examined, including multiple-solution branches and multiple regions of hysteresis. In addition, numerical results are presented for several selected aerofoils. Some of the aerofoils are found to contain markedly enlarged regions of hysteresis for certain critical cascade spacings.

  2. A meta-analysis of the freshwater trophic cascade.

    PubMed Central

    Brett, M T; Goldman, C R

    1996-01-01

    The generality of the trophic cascade has been an intensely debated topic among ecologists. We conducted a meta-analysis of 54 separate enclosure and pond experiments that measured the response of the zooplankton and phytoplankton to zooplanktivorous fish treatments. These results provide unequivocal support for the trophic cascade hypothesis in freshwater food webs. Zooplanktivorous fish treatments resulted in reduced zooplankton biomass and increased phytoplankton biomass. The trophic cascade was weakly dampened at the level of the phytoplankton. However, the response of the phytoplankton to the trophic cascade was highly skewed, with very strong responses in slightly more than one-third of the cases and weak responses in the others. PMID:11607694

  3. Contribution of convection and diffusion to the cascade reaction kinetics of β-galactosidase/glucose oxidase confined in a microchannel.

    PubMed

    Wu, Zeng-Qiang; Li, Zhong-Qiu; Li, Jin-Yi; Gu, Jing; Xia, Xing-Hua

    2016-05-25

    The spatial positioning of enzymes and mass transport play crucial roles in the functionality and efficiency of enzyme cascade reactions. To fully understand the mass transport regulating kinetics of enzyme cascade reactions, we investigated the contribution of convective and diffusive transports to a cascade reaction of β-galactosidase (β-Gal)/glucose oxidase (GOx) confined in a microchannel. β-Gal and GOx are assembled on two separated gold films patterned in a polydimethylsiloxane (PDMS) microchannel with a controllable distance from 50 to 100 μm. Experimental results demonstrated that the reaction yield increases with decreasing distance between two enzymes and increasing substrate flow rate. Together with the simulation results, we extracted individual reaction kinetics of the enzyme cascade reaction and found that the reaction rate catalyzed by β-Gal occurred much faster than by GOx, and thus, the β-Gal catalytic reaction showed diffusion controll, whereas the GOx catalytic reaction showed kinetic controll. Since the decrease in the enzymes distance shortens the transport length of intermediate glucose to GOx, the amount of glucose reaching GOx will be increased in the unit time, and in turn, the enzyme cascade reaction yield will be increased with decreasing the gap distance. This phenomenon is similar to the intermediates pool of tricarboxylic acid (TCA) cycle in the metabolic system. This study promotes the understanding of the metabolic/signal transduction processes and active transport in biological systems and promises to design high performance biosensors and biofuel cells systems. PMID:27174424

  4. AA amyloidosis as a complication of primary lymphedema.

    PubMed

    Beloncle, François; Sayegh, Johnny; Eymerit-Morin, Caroline; Duveau, Agnès; Augusto, Jean-François

    2014-03-01

    Primary lymphedema is a rare disease caused by a disorder of lymphangiogenesis. Clinical presentation and age at onset are variable. AA amyloidosis is usually due to chronic inflammatory diseases, malignant tumors or less frequently chronic infectious diseases. We report here the first two cases of AA amyloidosis present with renal failure and nephrotic syndrome in patients with primary lymphedema-induced chronic leg ulcers. The first patient was a 62-year-old female who presented with chronic untreated leg ulcers for 8 years secondary to primary lymphedema. A kidney biopsy done for nephrotic syndrome allowed the diagnosis of AA amyloidosis. The second patient was a 54-year-old male who presented with hereditary lymphedema and elephantiasis since the age of 12. A salivary gland biopsy allowed the diagnosis of AA amyloidosis. Renal function deteriorated progressively needing chronic haemodialysis. Chronic leg ulcers have been rarely reported to induce AA amyloidosis. Only five other cases have been reported in the literature, but none of them with chronic lymphedema. We believe that the relation between lymphedema, chronic leg ulcers and AA amyloidosis is underestimated. PMID:23964754

  5. Modulating the gut flora alters amino acid metabolism in neonatal pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intestinal microbes consume and produce amino acids (AA). This may impact intestinal threonine (THR) metabolism necessary for adequate gut function. We hypothesized that modulating the gut flora results in an alteration of intestinal THR utilization and hence whole body AA metabolism. Neonatal pigs ...

  6. Metabolomic profiling of amino acids and beta-cell function relative to insulin sensitivity in youth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In longitudinal studies of adults, elevated amino acid (AA) concentrations predicted future type 2 diabetes mellitus (T2DM). The aim of the present investigation was to examine whether increased plasma AA concentrations are associated with impaired beta-cell function relative to insulin sensitivity ...

  7. Contribution of Fermentation Yeast to Final Amino Acid Profile in DDGS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One major factor affecting DDGS quality and market values is amino acid (AA) composition. DDGS proteins come from corn and yeast. Yet, the effect of fermentation yeast on DDGS protein quantity and quality (AA profile) has not been well documented. Based on literature review, there are at least 4 met...

  8. Export of terrigenous organic carbon along submarine canyons driven by dense shelf water cascading

    NASA Astrophysics Data System (ADS)

    Tesi, T.; Puig, P.; Goni, M.; Canals, M.; Langone, L.; Palanques, A.; Miserocchi, S.; Heussner, S.; Trincardi, F.; Calafat, A.; Turchetto, M.; Fabres, J.; Durrieu de Madron, X.; Boldrin, A.

    2008-12-01

    At current highstand in sea level, shelves are considered major sites of terrigenous organic carbon (OCterr) accumulation with relatively little connectivity to the ocean interior. In recent years, the process of dense water cascading from the continental shelf, which occurs in numerous places around the world, has been suggested as carrier for OCterr to the deep ocean. The land-locked Mediterranean Sea is characterized by intense and recurrent cascades of dense shelf water. In winter, cold and dry winds cause the formation of dense water over the shelf that may overflow it and travel down to the outer margin and basin. Moored instruments were deployed in the canyons of the Gulf of Lion (France-Spain) and the Adriatic Sea (Italy) to intercept particulate material escaping the shelf and to investigate hydrodynamic and physical properties of the water column. Surface sediments along the shelves were also sampled to evaluate their contribution to the particle fluxes. The relative fractions of autochthonous and advected OC in sediment trap samples were investigated using biogeochemical proxies including alkaline CuO oxidation products (lignin phenols, dicarboxylic acids, and fatty acids), radiocarbon measurements (Ä14C), and elemental and carbon stable isotope (ä13C) compositions. Lignin-derived CuO products were a powerful biogeochemical tool that allowed us to identify the provenance of the material from the continental margin and to assess the amount of OCterr transferred across the slope in both Mediterranean regions. The results indicate that the composition of OC escaping the shelf through submarine canyons depends on the geomorphological setting. At the present sea level stage, cascading on a broad shelf limits the transport of OCterr, promoting instead the down-slope export of material accumulated in the mid- and outer-shelf. In contrast, cascade events on narrow shelves lead to the efficient export of OCterr from shallower regions of the margin along with

  9. Individual variation and intraclass correlation in arachidonic acid and eicosapentaenoic acid in chicken muscle

    PubMed Central

    2010-01-01

    Chicken meat with reduced concentration of arachidonic acid (AA) and reduced ratio between omega-6 and omega-3 fatty acids has potential health benefits because a reduction in AA intake dampens prostanoid signaling, and the proportion between omega-6 and omega-3 fatty acids is too high in our diet. Analyses for fatty acid determination are expensive, and finding the optimal number of analyses to give reliable results is a challenge. The objective of the present study was i) to analyse the intraclass correlation of different fatty acids in five meat samples, of one gram each, within the same chicken thigh, and ii) to study individual variations in the concentrations of a range of fatty acids and the ratio between omega-6 and omega-3 fatty acid concentrations among fifteen chickens. Fifteen newly hatched broilers were fed a wheat-based diet containing 4% rapeseed oil and 1% linseed oil for three weeks. Five muscle samples from the mid location of the thigh of each chicken were analysed for fatty acid composition. The intraclass correlation (sample correlation within the same animal) was 0.85-0.98 for the ratios of total omega-6 to total omega-3 fatty acids and of AA to eicosapentaenoic acid (EPA). This indicates that when studying these fatty acid ratios, one sample of one gram per animal is sufficient. However, due to the high individual variation between chicken for these ratios, a relatively high number of animals (minimum 15) are required to obtain a sufficiently high power to reveal significant effects of experimental factors (e.g. feeding regimes). The present experiment resulted in meat with a favorable concentration ratio between omega-6 and omega-3 fatty acids. The AA concentration varied from 1.5 to 2.8 g/100 g total fatty acids in thigh muscle in the fifteen broilers, and the ratio between AA and EPA concentrations ranged from 2.3 to 3.9. These differences among the birds may be due to genetic variance that can be exploited by breeding for lower AA

  10. Heavy quarkonium cascades in the glueball model

    SciTech Connect

    Zuk, J.; Joshi, G.C.

    1984-05-01

    The OZI ciolating two pion cascades between /sup 3/Si states of heavy quarkonium (V' ..-->.. V/sup pipi/) are studied in the Freund--Nambu model. When interpreted in the context of QCD, this model implies that OZI violation results from mixing with an intermediate glueball state. It is found that for an appropriate flavour--symmetry--breaking scheme, cascades between the same quantum numbers are satisfactorily described by varying only the quarkonium masses. Some predictions are made. But, the observed suppression of GAMMA(..gamma..'' ..-->.. ..gamma pi pi..)/GAMMA(..gamma..' ..-->.. ..gamma pi pi..)= indicates that the QQ bound state nature of heavy quarkonia is an important consideration in these decays. We show that the quarkonium couplings depend on overlap integrals between the wavefunctions of the mesons present at the decay vertex. We discuss various models that exploit the non-relativistic nature of heavy quarkonia, and from which such overlap integrals are derived in terms of ''charmonium--model'' radial wavefunctions.

  11. Frequency division using a micromechanical resonance cascade

    SciTech Connect

    Qalandar, K. R. Gibson, B.; Sharma, M.; Ma, A.; Turner, K. L.; Strachan, B. S.; Shaw, S. W.

    2014-12-15

    A coupled micromechanical resonator array demonstrates a mechanical realization of multi-stage frequency division. The mechanical structure consists of a set of N sequentially perpendicular microbeams that are connected by relatively weak elastic elements such that the system vibration modes are localized to individual microbeams and have natural frequencies with ratios close to 1:2:⋯:2{sup N}. Conservative (passive) nonlinear inter-modal coupling provides the required energy transfer between modes and is achieved by finite deformation kinematics. When the highest frequency beam is excited, this arrangement promotes a cascade of subharmonic resonances that achieve frequency division of 2{sup j} at microbeam j for j = 1, …, N. Results are shown for a capacitively driven three-stage divider in which an input signal of 824 kHz is passively divided through three modal stages, producing signals at 412 kHz, 206 kHz, and 103 kHz. The system modes are characterized and used to delineate the range of AC input voltages and frequencies over which the cascade occurs. This narrow band frequency divider has simple design rules that are scalable to higher frequencies and can be extended to a larger number of modal stages.

  12. Inverse Energy Cascades in Rotating Turbulence

    NASA Astrophysics Data System (ADS)

    Rosenberg, D. L.; Marino, R.; Mininni, P.; Pouquet, A.

    2013-12-01

    We present the results of direct numerical simulations (DNS) of rapidly rotating turbulent flows on grids of 20483 grid points that are forced at intermediate scales. Injection of energy at such scales at small Rossby numbers (~0.04) leads to a direct cascade toward small scales and an inverse cascade toward large scales. These results essentially validate those obtained using large eddy simulation (LES) (Sen et al., PRE 86:036319 (2012)): for a (helical) forcing that injects energy largely in 2D modes, the large scale energy spectrum scales as kperp-5/3, consistent with Kolmogorov-Kraichnan-Batchelor-Leith phenomenology; for a nonhelical isotropic forcing, the large scale energy spectrum scales as kperp-3. The (helical) anisotropic forcing DNS solution, like that of the LES models, shows a k-1 isotropic energy spectrum, which Sen et al. attribute to a large scale shear. The higher resolution of the DNS runs allows us to carry out probability distribution and conditional analyses that show that this interpretation may, in fact, be consistent with wall-bounded turbulent shear flow.

  13. Overflow cascades in liquid-infused substrates

    NASA Astrophysics Data System (ADS)

    Jacobi, I.; Wexler, J. S.; Stone, H. A.

    2015-08-01

    Liquid-infused patterned surfaces offer a promising new platform for generating omniphobic surface coatings. However, the liquid infused in these surfaces is susceptible to shear-driven dewetting. Recent work [Wexler et al., "Shear-driven failure of liquid-infused surfaces," Phys. Rev. Lett. 114, 168301 (2015)] has shown how the substrate pattern in these surfaces can be designed to exploit capillary forces in order to retain infused lubricants against the action of an immiscible shear flow. In this study, we explore the behavior of the infused lubricant when external shear causes the lubricant to overflow finite or "dead-end" surface features, resulting in either temporary or permanent lubricant loss. Microfluidic experiments illustrate how both geometry and chemical Marangoni stresses within liquid-infused surfaces generate an overflow cascade in which the lubricant escapes from the substrate and forms droplets on the surface, after which the droplets depin and are washed away by the external shear flow, allowing the overflow to repeat. General guidelines are developed to estimate the onset of the different stages of the cascade with the aim of providing additional robustness criteria for the design of future liquid-infused surfaces.

  14. Quantum dot quantum cascade infrared photodetector

    NASA Astrophysics Data System (ADS)

    Wang, Xue-Jiao; Zhai, Shen-Qiang; Zhuo, Ning; Liu, Jun-Qi; Liu, Feng-Qi; Liu, Shu-Man; Wang, Zhan-Guo

    2014-04-01

    We demonstrate an InAs quantum dot quantum cascade infrared photodetector operating at room temperature with a peak detection wavelength of 4.3 μm. The detector shows sensitive photoresponse for normal-incidence light, which is attributed to an intraband transition of the quantum dots and the following transfer of excited electrons on a cascade of quantum levels. The InAs quantum dots for the infrared absorption were formed by making use of self-assembled quantum dots in the Stranski-Krastanov growth mode and two-step strain-compensation design based on InAs/GaAs/InGaAs/InAlAs heterostructure, while the following extraction quantum stairs formed by LO-phonon energy are based on a strain-compensated InGaAs/InAlAs chirped superlattice. Johnson noise limited detectivities of 3.64 × 1011 and 4.83 × 106 Jones at zero bias were obtained at 80 K and room temperature, respectively. Due to the low dark current and distinct photoresponse up to room temperature, this device can form high temperature imaging.

  15. Quantum dot quantum cascade infrared photodetector

    SciTech Connect

    Wang, Xue-Jiao; Zhai, Shen-Qiang; Zhuo, Ning; Liu, Jun-Qi E-mail: fqliu@semi.ac.cn; Liu, Feng-Qi E-mail: fqliu@semi.ac.cn; Liu, Shu-Man; Wang, Zhan-Guo

    2014-04-28

    We demonstrate an InAs quantum dot quantum cascade infrared photodetector operating at room temperature with a peak detection wavelength of 4.3 μm. The detector shows sensitive photoresponse for normal-incidence light, which is attributed to an intraband transition of the quantum dots and the following transfer of excited electrons on a cascade of quantum levels. The InAs quantum dots for the infrared absorption were formed by making use of self-assembled quantum dots in the Stranski–Krastanov growth mode and two-step strain-compensation design based on InAs/GaAs/InGaAs/InAlAs heterostructure, while the following extraction quantum stairs formed by LO-phonon energy are based on a strain-compensated InGaAs/InAlAs chirped superlattice. Johnson noise limited detectivities of 3.64 × 10{sup 11} and 4.83 × 10{sup 6} Jones at zero bias were obtained at 80 K and room temperature, respectively. Due to the low dark current and distinct photoresponse up to room temperature, this device can form high temperature imaging.

  16. Cascade Distiller System Performance Testing Interim Results

    NASA Technical Reports Server (NTRS)

    Callahan, Michael R.; Pensinger, Stuart; Sargusingh, Miriam J.

    2014-01-01

    The Cascade Distillation System (CDS) is a rotary distillation system with potential for greater reliability and lower energy costs than existing distillation systems. Based upon the results of the 2009 distillation comparison test (DCT) and recommendations of the expert panel, the Advanced Exploration Systems (AES) Water Recovery Project (WRP) project advanced the technology by increasing reliability of the system through redesign of bearing assemblies and improved rotor dynamics. In addition, the project improved the CDS power efficiency by optimizing the thermoelectric heat pump (TeHP) and heat exchanger design. Testing at the NASA-JSC Advanced Exploration System Water Laboratory (AES Water Lab) using a prototype Cascade Distillation Subsystem (CDS) wastewater processor (Honeywell d International, Torrance, Calif.) with test support equipment and control system developed by Johnson Space Center was performed to evaluate performance of the system with the upgrades as compared to previous system performance. The system was challenged with Solution 1 from the NASA Exploration Life Support (ELS) distillation comparison testing performed in 2009. Solution 1 consisted of a mixed stream containing human-generated urine and humidity condensate. A secondary objective of this testing is to evaluate the performance of the CDS as compared to the state of the art Distillation Assembly (DA) used in the ISS Urine Processor Assembly (UPA). This was done by challenging the system with ISS analog waste streams. This paper details the results of the AES WRP CDS performance testing.

  17. Cascaded clocks measurement and simulation findings

    NASA Technical Reports Server (NTRS)

    Chislow, Don; Zampetti, George

    1994-01-01

    This paper will examine aspects related to network synchronization distribution and the cascading of timing elements. Methods of timing distribution have become a much debated topic in standards forums and among network service providers (both domestically and internationally). Essentially these concerns focus on the need to migrate their existing network synchronization plans (and capabilities) to those required for the next generation of transport technologies (namely, the Synchronous Digital Hierarchy (SDH), Synchronous Optical Networks (SONET), and Asynchronous Transfer Mode (ATM). The particular choices for synchronization distribution network architectures are now being evaluated and are demonstrating that they can indeed have a profound effect on the overall service performance levels that will be delivered to the customer. The salient aspects of these concerns reduce to the following: (1) identifying that the devil is in the details of the timing element specifications and the distribution of timing information (i.e., small design choices can have a large performance impact); (2) developing a standardized method of performance verification that will yield unambiguous results; and (3) presentation of those results. Specifically, this will be done for two general cases: an ideal input, and a noisy input to a cascaded chain of slave clocks.

  18. Multiplicative-cascade dynamics in pole balancing

    NASA Astrophysics Data System (ADS)

    Harrison, Henry S.; Kelty-Stephen, Damian G.; Vaz, Daniela V.; Michaels, Claire F.

    2014-06-01

    Pole balancing is a key task for probing the prospective control that organisms must engage in for purposeful action. The temporal structure of pole-balancing behaviors will reflect the on-line operation of control mechanisms needed to maintain an upright posture. In this study, signatures of multifractality are sought and found in time series of the vertical angle of a pole balanced on the fingertip. Comparisons to surrogate time series reveal multiplicative-cascade dynamics and interactivity across scales. In addition, simulations of a pole-balancing model generating on-off intermittency [J. L. Cabrera and J. G. Milton, Phys. Rev. Lett. 89, 158702 (2002), 10.1103/PhysRevLett.89.158702] were analyzed. Evidence of multifractality is also evident in simulations, though comparing simulated and participant series reveals a significantly greater contribution of cross-scale interactivity for the latter. These findings suggest that multiplicative-cascade dynamics are an extension of on-off intermittency and play a role in prospective coordination.

  19. Trophic cascade alters ecosystem carbon exchange

    PubMed Central

    Strickland, Michael S.; Hawlena, Dror; Reese, Aspen; Bradford, Mark A.; Schmitz, Oswald J.

    2013-01-01

    Trophic cascades—the indirect effects of carnivores on plants mediated by herbivores—are common across ecosystems, but their influence on biogeochemical cycles, particularly the terrestrial carbon cycle, are largely unexplored. Here, using a 13C pulse-chase experiment, we demonstrate how trophic structure influences ecosystem carbon dynamics in a meadow system. By manipulating the presence of herbivores and predators, we show that even without an initial change in total plant or herbivore biomass, the cascading effects of predators in this system begin to affect carbon cycling through enhanced carbon fixation by plants. Prolonged cascading effects on plant biomass lead to slowing of carbon loss via ecosystem respiration and reallocation of carbon among plant aboveground and belowground tissues. Consequently, up to 1.4-fold more carbon is retained in plant biomass when carnivores are present compared with when they are absent, owing primarily to greater carbon storage in grass and belowground plant biomass driven largely by predator nonconsumptive (fear) effects on herbivores. Our data highlight the influence that the mere presence of predators, as opposed to direct consumption of herbivores, can have on carbon uptake, allocation, and retention in terrestrial ecosystems. PMID:23776213

  20. Cascaded clocks measurement and simulation findings

    NASA Astrophysics Data System (ADS)

    Chislow, Don; Zampetti, George

    1994-05-01

    This paper will examine aspects related to network synchronization distribution and the cascading of timing elements. Methods of timing distribution have become a much debated topic in standards forums and among network service providers (both domestically and internationally). Essentially these concerns focus on the need to migrate their existing network synchronization plans (and capabilities) to those required for the next generation of transport technologies (namely, the Synchronous Digital Hierarchy (SDH), Synchronous Optical Networks (SONET), and Asynchronous Transfer Mode (ATM). The particular choices for synchronization distribution network architectures are now being evaluated and are demonstrating that they can indeed have a profound effect on the overall service performance levels that will be delivered to the customer. The salient aspects of these concerns reduce to the following: (1) identifying that the devil is in the details of the timing element specifications and the distribution of timing information (i.e., small design choices can have a large performance impact); (2) developing a standardized method of performance verification that will yield unambiguous results; and (3) presentation of those results. Specifically, this will be done for two general cases: an ideal input, and a noisy input to a cascaded chain of slave clocks.

  1. Flow characteristics of the Cascade granular blanket

    SciTech Connect

    Pitts, J.H.; Walton, O.R.

    1985-07-01

    Analysis of a single granule on a rotating cone shows that for the 35/sup 0/ half-angle, double-cone-shaped Cascade chamber, blanket granules will stay against the chamber wall if the rotational speed is 50 rpm or greater. The granules move axially down the wall with a slight (5-mm or less) sinusoidal oscillation in the circumferential direction. Granule chute-flow experiments confirm that two-layered flow can be obtained when the chute is inclined slightly above the granular material angle of repose. The top surface layer is thin and fast moving (supercritical flow). A thick bottom layer moves more slowly (subcritical flow controlled at the exit) with a velocity that increases with distance from the bottom of the chute. This is a desirable velocity profile because in the Cascade chamber about one-third of the fusion energy is deposited in the form of x rays and fusion-fuel-pellet debris in the top surface (inner-radius) layer.

  2. Flow characteristics of the Cascade granular blanket

    SciTech Connect

    Pitts, J.H.; Walton, O.R.

    1985-04-15

    Analysis of a single granule on a rotating cone shows that for the 35/sup 0/ half-angle, double-cone-shaped Cascade chamber, blanket granules will stay against the chamber wall if the rotational speed is 50 rpm or greater. The granules move axially down the wall with a slight (5-mm or less) sinusoidal oscillation in the circumferential direction. Granule chute-flow experiments confirm that two-layered flow can be obtained when the chute is inclined slightly above the granular material angle of repose. The top surface layer is thin and fast moving (supercritical flow). A thick bottom layer moves more slowly (subcritical flow controlled at the exit) with a velocity that increases with distance from the bottom of the chute. This is a desirable velocity profile because in the Cascade chamber about one-third of the fusion energy is deposited in the form of x rays and fusion-fuel-pellet debris in the top surface (inner-radius) layer.

  3. Ascorbic acid serum levels are reduced in patients with hematological malignancies

    PubMed Central

    Huijskens, Mirelle J.A.J.; Wodzig, Will K.W.H.; Walczak, Mateusz; Germeraad, Wilfred T.V.; Bos, Gerard M.J.

    2016-01-01

    In this paper we demonstrate that patients treated with chemotherapy and/or hematopoietic stem cell transplantation (HSCT) have highly significant reduced serum ascorbic acid (AA) levels compared to healthy controls. We recently observed in in vitro experiments that growth of both T and NK cells from hematopoietic stem cells is positively influenced by AA. It might be of clinical relevance to study the function and recovery of immune cells after intensive treatment, its correlation to AA serum levels and the possible effect of AA supplementation. PMID:27014565

  4. Ascorbic Acid and the Brain: Rationale for the Use against Cognitive Decline

    PubMed Central

    Harrison, Fiona E.; Bowman, Gene L.; Polidori, Maria Cristina

    2014-01-01

    This review is focused upon the role of ascorbic acid (AA, vitamin C) in the promotion of healthy brain aging. Particular attention is attributed to the biochemistry and neuronal metabolism interface, transport across tissues, animal models that are useful for this area of research, and the human studies that implicate AA in the continuum between normal cognitive aging and age-related cognitive decline up to Alzheimer’s disease. Vascular risk factors and comorbidity relationships with cognitive decline and AA are discussed to facilitate strategies for advancing AA research in the area of brain health and neurodegeneration. PMID:24763117

  5. Quaternary Magmatism in the Cascades - Geologic Perspectives

    USGS Publications Warehouse

    Hildreth, Wes

    2007-01-01

    Foreward The Cascade magmatic arc is a belt of Quaternary volcanoes that extends 1,250 km from Lassen Peak in northern California to Meager Mountain in Canada, above the subduction zone where the Juan de Fuca Plate plunges beneath the North American Plate. This Professional Paper presents a synthesis of the entire volcanic arc, addressing all 2,300 known Quaternary volcanoes, not just the 30 or so visually prominent peaks that comprise the volcanic skyline. Study of Cascade volcanoes goes back to the geological explorers of the late 19th century and the seminal investigations of Howel Williams in the 1920s and 1930s. However, major progress and application of modern scientific methods and instrumentation began only in the 1970s with the advent of systematic geological, geophysical, and geochemical studies of the entire arc. Initial stimulus from the USGS Geothermal Research Program was enhanced by the USGS Volcano Hazards Program following the 1980 eruption of Mount St. Helens. Together, these two USGS Programs have provided more than three decades of stable funding, staffing, and analytical support. This Professional Paper summarizes the resultant USGS data sets and integrates them with the parallel contributions of other investigators. The product is based upon an all-encompassing and definitive geological database, including chemical and isotopic analyses to characterize the rocks and geochronology to provide the critical time constraints. Until now, this massive amount of data has not been summarized, and a systematic and uniform interpretation firmly grounded in geological fact has been lacking. Herein lies the primary utility of this Cascade volume. It not only will be the mandatory starting point for new workers, but also will provide essential geological context to broaden the perspectives of current investigators of specific Cascade volcanoes. Wes Hildreth's insightful understanding of volcanic processes and his uncompromising scientific integrity make him

  6. Arachidonic acid stimulates DNA synthesis in brown preadipocytes through the activation of protein kinase C and MAPK.

    PubMed

    Garcia, Bibian; Martinez-de-Mena, Raquel; Obregon, Maria-Jesus

    2012-10-01

    Arachidonic acid (AA) is a polyunsaturated fatty acid that stimulates the proliferation of many cellular types. We studied the mitogenic potential of AA in rat brown preadipocytes in culture and the signaling pathways involved. AA is a potent mitogen which induces 4-fold DNA synthesis in brown preadipocytes. The AA mitogenic effect increases by NE addition. AA also increases the mitogenic action of different growth factor combinations. Other unsaturated and saturated fatty acids do not stimulate DNA synthesis to the same extent as AA. We analyzed the role of PKC and MEK/MAPK signaling pathways. PKC inhibition by bisindolilmaleimide I (BIS) abolishes AA and phorbol ester stimulation of DNA synthesis and reduces the mitogenic activity of different growth factors in brown preadipocytes. Brown preadipocytes in culture express PKC α, δ, ε and ζ isoforms. Pretreatment with high doses of the phorbol ester PDBu, induces downregulation of PKCs ε and δ and reproduces the effect of BIS indicating that AA-dependent induction of DNA synthesis requires PKC activity. AA also activates MEK/MAPK pathway and the inhibition of MEK activity inhibits AA stimulation of DNA synthesis and brown adipocyte proliferation. Inhibition of PKC δ by rottlerin abolishes AA-dependent stimulation of DNA synthesis and MAPK activation, whereas PKC ε inhibition does not produce any effect. In conclusion, our results identify AA as a potent mitogen for brown adipocytes and demonstrate the involvement of the PDBu-sensitive PKC δ isoform and MEK/MAPK pathway in AA-induced proliferation of brown adipocytes. Increased proliferative activity might increase the thermogenic capacity of brown fat. PMID:22766489

  7. Aerodynamic development and investigation of turbine transonic rotor blade cascades

    NASA Astrophysics Data System (ADS)

    Mayorskiy, E. V.; Mamaev, B. I.

    2015-05-01

    An intricate nature of the pattern in which working fluid flows over transonic blade cascades generates the need for experimentally studying their characteristics in designing them. Three cascades having identical main geometrical parameters and differing from one another only in the suction side curvature in the outlet area between the throat and trailing edge were tested in optimizing the rotor blade cascade for the reduced flow outlet velocity λ2 ≈ 1. In initial cascade 1, its curvature decreased monotonically toward the trailing edge. In cascade 2, the suction side curvature near the trailing edge was decreased, but the section near the throat had a larger curvature. In cascade 3, a profile with inverse concavity near the trailing edge was used. The cascades were blown at λ2 = 0.7-1.2 and at different incidence angles. The distribution of pressure over the profiles, profile losses, and the outlet angle were measured. Cascade 1 showed efficient performance in the design mode and under the conditions of noticeable deviations from it with respect to the values of λ2 and incidence angle. In cascade 2, flow separation zones were observed at the trailing edge, as well as an increased level of losses. Cascade 3 was found to be the best one: it had reduced positive pressure gradients as compared with cascade 1, and the relative reduction of losses in the design mode was equal to 24%. The profiles with inverse concavity on the suction side near the trailing edge were recommended for being used in heavily loaded turbine stages.

  8. 40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for CH4 and N2O

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Kraft Lime Kiln and Calciner Emissions... Manufacturing Pt. 98, Subpt. AA, Table AA -2 Table AA-2 to Subpart AA of Part 98—Kraft Lime Kiln and Calciner Emissions Factors for CH4 and N2O Fuel Fossil fuel-based emissions factors (kg/mmBtu HHV) Kraft lime...

  9. Easy modification of glassy carbon electrode for simultaneous determination of ascorbic acid, dopamine and uric acid.

    PubMed

    Thiagarajan, Soundappan; Tsai, Tsung-Hsuan; Chen, Shen-Ming

    2009-04-15

    A glassy carbon electrode (GCE) has been modified by electrochemical oxidation in mild acidic media (0.1 mol l(-1) H(2)SO(4)) and could be applied for individual and simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Oxidized GCE shows a single redox couple (E(0)'=-2.5 mV) which is based on the formation functional groups during the electrochemical pretreatment process. Proposed GCE successfully decreases the over potentials for the oxidation process of these species (AA, DA and UA) comparing with bare GCE. The oxidized GCE has its own simplicity, stability, high sensitivity and possesses the potential for simultaneous determination of AA, DA and UA. PMID:19162467

  10. Regulatory signals for intestinal amino acid transporters and peptidases

    SciTech Connect

    Ferraris, R.P.; Kwan, W.W.; Diamond, J. )

    1988-08-01

    Dietary protein ultimately regulates many processes involved in protein digestion, but it is often unclear whether proteins themselves, peptides, or amino acids (AAs) are the proximate regulatory signal. Hence the authors compared several processes involved in protein digestion in mice adapted to one of three rations, identical except for containing 54% of either casein, a partial hydrolysate of casein, or a free AA mixture simulating a complete hydrolysate of casein. The authors measured brush-border uptakes of seven AAs that variously serve as substrates for four AA transporters, and brush-border and cytosolic activities of four peptidases. The three rations yielded essentially the same AA uptake rates. Peptidase activities tended to be lower on the AA ration than on the protein ration. In other studies, all three rations yielded the same rates of brush-border peptide uptake; protein is only modestly more effective than AAs at inducing synthesis of pancreatic proteases; and, depending on the animal species, protein is either much less or much more effective than AAs at stimulating release of cholecystokinin and hence of pancreatic enzymes. Thus the regulators of each process involved in protein digestion are not necessarily that process's substrate.

  11. Prenatal arachidonic acid exposure and selected immune-related variables in childhood.

    PubMed

    Dirix, Chantal E H; Hogervorst, Janneke G F; Rump, Patrick; Hendriks, Johannes J E; Bruins, Maaike; Hornstra, Gerard

    2009-08-01

    Arachidonic acid (AA) is considered essential in fetal development and some of its metabolites are thought to be important mediators of the immune responses. Therefore, we studied whether prenatal exposure to AA is associated with some immune-related clinical conditions and plasma markers in childhood. In 280 children aged 7 years, atopy, lung function and plasma inflammation markers were measured and their relationships with early AA exposure were studied by linear and logistic regression analyses. AA exposure was deduced from AA concentrations in plasma phospholipids of the mothers collected at several time points during pregnancy and at delivery, and in umbilical cord plasma and arterial and venous wall phospholipids. In unadjusted regression analyses, significant positive associations were observed between maternal AA concentrations at 16 and 32 weeks of pregnancy (proxies for fetal AA exposure) and peak expiratory flow decline after maximal physical exercise and plasma fibrinogen concentrations of their children, respectively. However, after correction for relevant covariables, only trends remained. A significant negative relationship was observed between AA concentrations in cord plasma (reflecting prenatal AA exposure) and the average daily amplitude of peak expiratory flow at rest, which lost significance after appropriate adjustment. Because of these few, weak and inconsistent relationships, a major impact of early-life exposure to AA on atopy, lung function and selected plasma inflammation markers of children at 7 years of age seems unlikely. PMID:19173768

  12. Ascorbic Acid and BSA Protein in Solution and Films: Interaction and Surface Morphological Structure

    PubMed Central

    Maciel, Rafael R. G.; de Almeida, Adriele A.; Godinho, Odin G. C.; Gorza, Filipe D. S.; Pedro, Graciela C.; Trescher, Tarquin F.; Silva, Josmary R.; de Souza, Nara C.

    2013-01-01

    This paper reports on the study of the interactions between ascorbic acid (AA) and bovine serum albumin (BSA) in aqueous solution as well as in films (BSA/AA films) prepared by the layer-by-layer technique. Regarding to solution studies, a hyperchromism (in the range of ultraviolet) was found as a function of AA concentration, which suggested the formation of aggregates from AA and BSA. Binding constant, K, determined for aggregates from BSA and AA was found to be about 102 M−1, which indicated low affinity of AA with BSA. For the BSA/AA films, it was also noted that the AA adsorption process and surface morphological structures depended on AA concentration. By changing the contact time between the AA and BSA, a hypochromism was revealed, which was associated to decrease of accessibility of solvent to tryptophan due to formation of aggregates. Furthermore, different morphological structures of aggregates were observed, which were attributed to the diffusion-limited aggregation. Since most of studies of interactions of drugs and proteins are performed in solution, the analysis of these processes by using films can be very valuable because this kind of system is able to employ several techniques of investigation in solid state. PMID:23984366

  13. Ascorbic acid and BSA protein in solution and films: interaction and surface morphological structure.

    PubMed

    Maciel, Rafael R G; de Almeida, Adriele A; Godinho, Odin G C; Gorza, Filipe D S; Pedro, Graciela C; Trescher, Tarquin F; Silva, Josmary R; de Souza, Nara C

    2013-01-01

    This paper reports on the study of the interactions between ascorbic acid (AA) and bovine serum albumin (BSA) in aqueous solution as well as in films (BSA/AA films) prepared by the layer-by-layer technique. Regarding to solution studies, a hyperchromism (in the range of ultraviolet) was found as a function of AA concentration, which suggested the formation of aggregates from AA and BSA. Binding constant, K, determined for aggregates from BSA and AA was found to be about 10(2) M(-1), which indicated low affinity of AA with BSA. For the BSA/AA films, it was also noted that the AA adsorption process and surface morphological structures depended on AA concentration. By changing the contact time between the AA and BSA, a hypochromism was revealed, which was associated to decrease of accessibility of solvent to tryptophan due to formation of aggregates. Furthermore, different morphological structures of aggregates were observed, which were attributed to the diffusion-limited aggregation. Since most of studies of interactions of drugs and proteins are performed in solution, the analysis of these processes by using films can be very valuable because this kind of system is able to employ several techniques of investigation in solid state. PMID:23984366

  14. Expression of apical Na(+)-L-glutamine co-transport activity, B(0)-system neutral amino acid co-transporter (B(0)AT1) and angiotensin-converting enzyme 2 along the jejunal crypt-villus axis in young pigs fed a liquid formula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gut apical amino acid (AA) transport activity is high at birth and during suckling, thus being essential to maintain luminal nutrient-dependent mucosal growth through providing AA as essential metabolic fuel, substrates and nutrient stimuli for cellular growth. Because system-B(0) Na(+)-neutral AA c...

  15. Amino acid supplementation alters bone metabolism during simulated weightlessness

    NASA Technical Reports Server (NTRS)

    Zwart, S. R.; Davis-Street, J. E.; Paddon-Jones, D.; Ferrando, A. A.; Wolfe, R. R.; Smith, S. M.

    2005-01-01

    High-protein and acidogenic diets induce hypercalciuria. Foods or supplements with excess sulfur-containing amino acids increase endogenous sulfuric acid production and therefore have the potential to increase calcium excretion and alter bone metabolism. In this study, effects of an amino acid/carbohydrate supplement on bone resorption were examined during bed rest. Thirteen subjects were divided at random into two groups: a control group (Con, n = 6) and an amino acid-supplemented group (AA, n = 7) who consumed an extra 49.5 g essential amino acids and 90 g carbohydrate per day for 28 days. Urine was collected for n-telopeptide (NTX), deoxypyridinoline (DPD), calcium, and pH determinations. Bone mineral content was determined and potential renal acid load was calculated. Bone-specific alkaline phosphatase was measured in serum samples collected on day 1 (immediately before bed rest) and on day 28. Potential renal acid load was higher in the AA group than in the Con group during bed rest (P < 0.05). For all subjects, during bed rest urinary NTX and DPD concentrations were greater than pre-bed rest levels (P < 0.05). Urinary NTX and DPD tended to be higher in the AA group (P = 0.073 and P = 0.056, respectively). During bed rest, urinary calcium was greater than baseline levels (P < 0.05) in the AA group but not the Con group. Total bone mineral content was lower after bed rest than before bed rest in the AA group but not the Con group (P < 0.05). During bed rest, urinary pH decreased (P < 0.05), and it was lower in the AA group than the Con group. These data suggest that bone resorption increased, without changes in bone formation, in the AA group.

  16. Cloning and epitope mapping of Cry11Aa-binding sites in the Cry11Aa-receptor alkaline phosphatase from Aedes aegypti.

    PubMed

    Fernandez, Luisa E; Martinez-Anaya, Claudia; Lira, Erandi; Chen, Jianwu; Evans, Amy; Hernández-Martínez, Salvador; Lanz-Mendoza, Humberto; Bravo, Alejandra; Gill, Sarjeet S; Soberón, Mario

    2009-09-22

    Cry11Aa is the most active Bacillus thuringiensis israelensis toxin against Aedes aegypti larvae. Ae. aegypti alkaline phosphatase (ALP) was previously identified as a Cry11Aa receptor mediating toxicity. Here we report the cloning and functional characterization of this Ae. aegypti Cry11Aa-ALP receptor. Of three ALP's cDNA clones, the recombinant produced ALP1 isoform was shown to bind Cry11Aa and P1.BBMV peptide phage that specifically binds the midgut ALP-Cry11Aa receptor. An anti-ALP1 antibody inhibited binding to brush border membrane vesicles and toxicity of Cry11Aa in isolated cultured guts. Two ALP1 Cry11Aa binding regions (R59-G102 and N257-I296) were mapped by characterizing binding of Cry11Aa to nine recombinant overlapping peptides covering the ALP1 sequence. Finally, by using a peptide spot array of Cry11Aa domain III and site-directed mutagenesis, we show that the ALP1 R59-G102 region binds Cry11Aa through domain II loop alpha-8 while ALP1 N257-I296 interacts with Cry11Aa through domain III 561RVQSQNSGNN570 located in beta18-beta19. Our results show that Cry11Aa domain II and domain III are involved in the binding with two distinct binding sites in the ALP1 receptor. PMID:19697959

  17. Cloning and Epitope Mapping of Cry11Aa-Binding Sites in the Cry11Aa-Receptor Alkaline Phosphatase from Aedes aegypti†

    PubMed Central

    Fernandez, Luisa E.; Martinez-Anaya, Claudia; Lira, Erandi; Chen, Jianwu; Evans, Amy; Hernández-Martínez, Salvador; Lanz-Mendoza, Humberto; Bravo, Alejandra; Gill, Sarjeet S.; Soberón, Mario

    2013-01-01

    Cry11Aa is the most active Bacillus thuringiensis israelensis toxin against Aedes aegypti larvae. Ae. aegypti alkaline phosphatase (ALP) was previously identified as a Cry11Aa receptor mediating toxicity. Here we report the cloning and functional characterization of this Ae. aegypti Cry11Aa-ALP receptor. Of three ALP’s cDNA clones, the recombinant produced ALP1 isoform was shown to bind Cry11Aa and P1.BBMV peptide phage that specifically binds the midgut ALP-Cry11Aa receptor. An anti-ALP1 antibody inhibited binding to brush border membrane vesicles and toxicity of Cry11Aa in isolated cultured guts. Two ALP1 Cry11Aa binding regions (R59–G102 and N257–I296) were mapped by characterizing binding of Cry11Aa to nine recombinant overlapping peptides covering the ALP1 sequence. Finally, by using a peptide spot array of Cry11Aa domain III and site-directed mutagenesis, we show that the ALP1 R59–G102 region binds Cry11Aa through domain II loop α-8 while ALP1 N257–I296 interacts with Cry11Aa through domain III 561RVQSQNSGNN570 located in β18-β19. Our results show that Cry11Aa domain II and domain III are involved in the binding with two distinct binding sites in the ALP1 receptor. PMID:19697959

  18. Amyloid beta peptide and NMDA induce ROS from NADPH oxidase and AA release from cytosolic phospholipase A2 in cortical neurons.

    PubMed

    Shelat, Phullara B; Chalimoniuk, Malgorzata; Wang, Jing-Hung; Strosznajder, Joanna B; Lee, James C; Sun, Albert Y; Simonyi, Agnes; Sun, Grace Y

    2008-07-01

    Increase in oxidative stress has been postulated to play an important role in the pathogenesis of a number of neurodegenerative diseases including Alzheimer's disease. There is evidence for involvement of amyloid-beta peptide (Abeta) in mediating the oxidative damage to neurons. Despite yet unknown mechanism, Abeta appears to exert action on the ionotropic glutamate receptors, especially the N-methyl-D-aspartic acid (NMDA) receptor subtypes. In this study, we showed that NMDA and oligomeric Abeta(1-42) could induce reactive oxygen species (ROS) production from cortical neurons through activation of NADPH oxidase. ROS derived from NADPH oxidase led to activation of extracellular signal-regulated kinase 1/2, phosphorylation of cytosolic phospholipase A(2)alpha (cPLA(2)alpha), and arachidonic acid (AA) release. In addition, Abeta(1-42)-induced AA release was inhibited by d(-)-2-amino-5-phosphonopentanoic acid and memantine, two different NMDA receptor antagonists, suggesting action of Abeta through the NMDA receptor. Besides serving as a precursor for eicosanoids, AA is also regarded as a retrograde messenger and plays a role in modulating synaptic plasticity. Other phospholipase A(2) products such as lysophospholipids can perturb membrane phospholipids. These results suggest an oxidative-degradative mechanism for oligomeric Abeta(1-42) to induce ROS production and stimulate AA release through the NMDA receptors. This novel mechanism may contribute to the oxidative stress hypothesis and synaptic failure that underline the pathogenesis of Alzheimer's disease. PMID:18346200

  19. Interferon-gamma-inducible kynurenines/pteridines inflammation cascade: implications for aging and aging-associated psychiatric and medical disorders

    PubMed Central

    2010-01-01

    This review of literature and our data suggests that up-regulated production of interferon-gamma (IFNG) in periphery and brain triggers a merger of tryptophan (TRY)–kynurenine (KYN) and guanine–tetrahydrobiopterin (BH4) metabolic pathways into inflammation cascade involved in aging and aging-associated medical and psychiatric disorders (AAMPD) (metabolic syndrome, depression, vascular cognitive impairment). IFNG-inducible KYN/pteridines inflammation cascade is characterized by up-regulation of nitric oxide synthase (NOS) activity (induced by KYN) and decreased formation of NOS cofactor, BH4, that results in uncoupling of NOS that shifting arginine from NO to superoxide anion production. Superoxide anion and free radicals among KYN derivatives trigger phospholipase A2-arachidonic acid cascade associated with AAMPD. IFNG-induced up-regulation of indoleamine 2,3-dioxygenase (IDO), rate-limiting enzyme of TRY–KYN pathway, decreases TRY conversion into serotonin (substrate of antidepressant effect) and increases production of KYN associated with diabetes [xanthurenic acid (XA)], anxiety (KYN), psychoses and cognitive impairment (kynurenic acid). IFNG-inducible KYN/pteridines inflammation cascade is impacted by IFNG (+874) T/A genotypes, encoding cytokine production. In addition to literature data on KYN/TRY ratio (IDO activity index), we observe neopterin levels (index of activity of rate-limiting enzyme of guanine–BH4 pathway) to be higher in carriers of high (T) than of low (A) producers alleles; and to correlate with AAMPD markers (e.g., insulin resistance, body mass index, mortality risk), and with IFN-alpha-induced depression in hepatitis C patients. IFNG-inducible cascade is influenced by environmental factors (e.g., vitamin B6 deficiency increases XA formation) and by pharmacological agents; and might offer new approaches for anti-aging and anti-AAMPD interventions. PMID:20811799

  20. Effects of Dimethylaminoethanol and Compound Amino Acid on D-Galactose Induced Skin Aging Model of Rat

    PubMed Central

    Liu, Su; Chen, Zhenyu; Cai, Xia; Sun, Ying; Zhao, Cailing

    2014-01-01

    A lasting dream of human beings is to reverse or postpone aging. In this study, dimethylaminoethanol (DMAE) and compound amino acid (AA) in Mesotherapy were investigated for their potential antiaging effects on D-galactose induced aging skin. At 18 days after D-gal induction, each rat was treated with intradermal microinjection of saline, AA, 0.1% DMAE, 0.2% DMAE, 0.1% DMAE + AA, or 0.2% DMAE + AA, respectively. At 42 days after treatment, the skin wound was harvested and assayed. Measurement of epidermal and dermal thickness in 0.1% DMAE + AA and 0.2% DMAE + AA groups appeared significantly thicker than aging control rats. No differences were found in tissue water content among groups. Hydroxyproline in 0.1% DMAE + AA, 0.2% DMAE + AA, and sham control groups was much higher than all other groups. Collagen type I, type III, and MMP-1 expression was highly upregulated in both 0.1% DMAE + AA and 0.2% DMAE + AA groups compared with aging control. In contrast, TIMP-1 expression levels of various aging groups were significantly reduced when compared to sham control. Coinjection of DMAE and AA into target tissue has marked antiaging effects on D-galactose induced skin aging model of rat. PMID:25133239

  1. Effects of dimethylaminoethanol and compound amino acid on D-galactose induced skin aging model of rat.

    PubMed

    Liu, Su; Chen, Zhenyu; Cai, Xia; Sun, Ying; Zhao, Cailing; Liu, Fangjun; Liu, Dalie

    2014-01-01

    A lasting dream of human beings is to reverse or postpone aging. In this study, dimethylaminoethanol (DMAE) and compound amino acid (AA) in Mesotherapy were investigated for their potential antiaging effects on D-galactose induced aging skin. At 18 days after D-gal induction, each rat was treated with intradermal microinjection of saline, AA, 0.1% DMAE, 0.2% DMAE, 0.1% DMAE + AA, or 0.2% DMAE + AA, respectively. At 42 days after treatment, the skin wound was harvested and assayed. Measurement of epidermal and dermal thickness in 0.1% DMAE + AA and 0.2% DMAE + AA groups appeared significantly thicker than aging control rats. No differences were found in tissue water content among groups. Hydroxyproline in 0.1% DMAE + AA, 0.2% DMAE + AA, and sham control groups was much higher than all other groups. Collagen type I, type III, and MMP-1 expression was highly upregulated in both 0.1% DMAE + AA and 0.2% DMAE + AA groups compared with aging control. In contrast, TIMP-1 expression levels of various aging groups were significantly reduced when compared to sham control. Coinjection of DMAE and AA into target tissue has marked antiaging effects on D-galactose induced skin aging model of rat. PMID:25133239

  2. Amino Acid Polymorphisms in Hepatitis C Virus Core Affect Infectious Virus Production and Major Histocompatibility Complex Class I Molecule Expression.

    PubMed

    Tasaka-Fujita, Megumi; Sugiyama, Nao; Kang, Wonseok; Masaki, Takahiro; Masaski, Takahiro; Murayama, Asako; Yamada, Norie; Sugiyama, Ryuichi; Tsukuda, Senko; Watashi, Koichi; Asahina, Yasuhiro; Sakamoto, Naoya; Wakita, Takaji; Shin, Eui-Cheol; Kato, Takanobu

    2015-01-01

    Amino acid (aa) polymorphisms in the hepatitis C virus (HCV) genotype 1b core protein have been reported to be a potent predictor for poor response to interferon (IFN)-based therapy and a risk factor for hepatocarcinogenesis. We investigated the effects of these polymorphisms with genotype 1b/2a chimeric viruses that contained polymorphisms of Arg/Gln at aa 70 and Leu/Met at aa 91. We found that infectious virus production was reduced in cells transfected with chimeric virus RNA that had Gln at aa 70 (aa70Q) compared with RNA with Arg at aa 70 (aa70R). Using flow cytometry analysis, we confirmed that HCV core protein accumulated in aa70Q clone transfected cells, and it caused a reduction in cell-surface expression of major histocompatibility complex (MHC) class I molecules induced by IFN treatment through enhanced protein kinase R phosphorylation. We could not detect any effects due to the polymorphism at aa 91. In conclusion, the polymorphism at aa 70 was associated with efficiency of infectious virus production, and this deteriorated virus production in strains with aa70Q resulted in the intracellular accumulation of HCV proteins and attenuation of MHC class I molecule expression. These observations may explain the strain-associated resistance to IFN-based therapy and hepatocarcinogenesis of HCV. PMID:26365522

  3. Anthranilic Acid: A Potential Biomarker and Treatment Target for Schizophrenia

    PubMed Central

    Oxenkrug, Gregory; van der Hart, Marieke; Roeser, Julien; Summergrad, Paul

    2016-01-01

    Dysregulation of Trp-Kyn pathway is the most recent hypothesis of mechanisms of schizophrenia. In particular, over-production of kynurenic acid (KYNA), one of the three immediate downstream metabolites of kynurenine (Kyn) along tryptophan (Trp): Kyn pathway, has been considered as a new target for therapeutic intervention in schizophrenia. Up-regulation of KYNA formation was suggested to occur at the expense of down-regulated production of 3-hydroxyKyn (3-HK), the second immediate downstream metabolite of Kyn. We were interested to assess the third immediate downstream Kyn metabolite, anthranilic acid (AA). Serum AA concentrations were evaluated in schizophrenia patients and control subjects by HPLC-mass spectrometry method. We found 2-fold increase of AA and 3-fold decrease of 3-HK concentrations in serum of schizophrenia patients. Up regulated formation of AA might contribute to mechanisms of schizophrenia considering experimental evidences of AA augmentation of autoimmune processes in rat and mice; clinical findings of AA elevation in rheumatoid arthritis and type 1 diabetes, autoimmune diseases diametrical to schizophrenia; and involvement of autoimmunity in development of schizophrenia. Present data warrant further studies of AA as biological marker in, at least, a subgroup (associated with autoimmune mechanisms) of schizophrenia patients and as a new target for therapeutic intervention. PMID:27042691

  4. Laboratory study on the behaviour of spent AA household alkaline batteries in incineration

    SciTech Connect

    Almeida, Manuel F. Xara, Susana M.; Delgado, Julanda; Costa, Carlos A.

    2009-01-15

    The quantitative evaluation of emissions from incineration is essential when Life Cycle Assessment (LCA) studies consider this process as an end-of-life solution for some wastes. Thus, the objective of this work is to quantify the main gaseous emissions produced when spent AA alkaline batteries are incinerated. With this aim, batteries were kept for 1 h at 1273 K in a refractory steel tube hold in a horizontal electric furnace with temperature control. At one end of the refractory steel tube, a constant air flow input assures the presence of oxygen in the atmosphere and guides the gaseous emissions to a filter system followed by a set of two bubbler flasks having an aqueous solution of 10% (v/v) nitric acid. After each set of experiments, sulphur, chlorides and metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Tl and Zn) were analyzed in both the solutions obtained from the steel tube washing and from the bubblers. Sulphur, chlorides and metals were quantified, respectively, using barium sulfate gravimetry, the Volhard method and atomic absorption spectrometry (AAS). The emissions of zinc, the most emitted metal, represent about 6.5% of the zinc content in the batteries. Emissions of manganese (whose oxide is the main component of the cathode) and iron (from the cathode collector) are negligible when compared with their amount in AA alkaline batteries. Mercury is the metal with higher volatility in the composition of the batteries and was collected even in the second bubbler flask. The amount of chlorides collected corresponds to about 36% of the chlorine in the battery sleeve that is made from PVC. A considerable part of the HCl formed in PVC plastic sleeve incineration is neutralized with KOH, zinc and manganese oxides and, thus, it is not totally released in the gas. Some of the emissions are predictable through a thermodynamic data analysis at temperatures in the range of 1200-1300 K taking into account the composition of the batteries. This analysis was done

  5. Laboratory study on the behaviour of spent AA household alkaline batteries in incineration.

    PubMed

    Almeida, Manuel F; Xará, Susana M; Delgado, Julanda; Costa, Carlos A

    2009-01-01

    The quantitative evaluation of emissions from incineration is essential when Life Cycle Assessment (LCA) studies consider this process as an end-of-life solution for some wastes. Thus, the objective of this work is to quantify the main gaseous emissions produced when spent AA alkaline batteries are incinerated. With this aim, batteries were kept for 1h at 1273K in a refractory steel tube hold in a horizontal electric furnace with temperature control. At one end of the refractory steel tube, a constant air flow input assures the presence of oxygen in the atmosphere and guides the gaseous emissions to a filter system followed by a set of two bubbler flasks having an aqueous solution of 10% (v/v) nitric acid. After each set of experiments, sulphur, chlorides and metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Tl and Zn) were analyzed in both the solutions obtained from the steel tube washing and from the bubblers. Sulphur, chlorides and metals were quantified, respectively, using barium sulfate gravimetry, the Volhard method and atomic absorption spectrometry (AAS). The emissions of zinc, the most emitted metal, represent about 6.5% of the zinc content in the batteries. Emissions of manganese (whose oxide is the main component of the cathode) and iron (from the cathode collector) are negligible when compared with their amount in AA alkaline batteries. Mercury is the metal with higher volatility in the composition of the batteries and was collected even in the second bubbler flask. The amount of chlorides collected corresponds to about 36% of the chlorine in the battery sleeve that is made from PVC. A considerable part of the HCl formed in PVC plastic sleeve incineration is neutralized with KOH, zinc and manganese oxides and, thus, it is not totally released in the gas. Some of the emissions are predictable through a thermodynamic data analysis at temperatures in the range of 1200-1300K taking into account the composition of the batteries. This analysis was done

  6. Long noncoding RNA HIF1A-AS1A reduces apoptosis of vascular smooth muscle cells: implications for the pathogenesis of thoracoabdominal aorta aneurysm.

    PubMed

    He, Qing; Tan, Jinyun; Yu, Bo; Shi, Weihao; Liang, Kun

    2015-05-01

    Long non-coding RNAs (IncRNAs) play important roles in various biological processes, such as transcriptional regulation, cell growth and tumorigenesis. However, little is known about the role of IncRNA HIF 1 alpha-antisense RNA 1 (HIF1a-AS1) in regulating the proliferation and apoptosis of vascular smooth muscle cells (VSMCs) and the expression of HIF1a-AS1 in serum of thoracoabdominal aortic aneurysm (TAAA) patients. The cell viability was detected by the CCK8 assay. The cell apoptosis was assessed by annexin V-PI double-labeling staining. Expression of genes and proteins were analyzed by real-time PCR and western blotting, respectively. Cells were transfected with siRNAs as a gene silencing method. In serum of TAAA patients, the expression of HIF1a-AS1 was significantly increased (superior to 6-fold) compared to the normal control. Moreover, Palmitic acid (PA) induced cell apoptosis in VSMCs in a time- and dose-dependent manner, and the proportion of the apoptotic cells had gained as compared to untreatment group. PA also induced up-regulation expression of HIF1a-AS1. We also found that transfection of cells with HIF1a-AS1 siRNA decreased the expression of caspase-3 and caspase-8 and increased the expression of Bcl2, and protected PA-induced cell apoptosis in VSMCs. HIF1a-AS1 was overexpressed in the TAAA and the interaction between HIF1a-AS1 and apoptotic proteins plays a key role in the proliferation and apoptosis of VSMCs in vitro, which may contribute to the pathogenesis of TAAA. PMID:26062299

  7. Eruptive history of South Sister, Oregon Cascades

    USGS Publications Warehouse

    Fierstein, J.; Hildreth, W.; Calvert, A.T.

    2011-01-01

    South Sister is southernmost and highest of the Three Sisters, three geologically dissimilar stratovolcanoes that together form a spectacular 20km reach along the Cascade crest in Oregon. North Sister is a monotonously mafic edifice as old as middle Pleistocene, Middle Sister a basalt-andesite-dacite cone built between 48 and 14ka, and South Sister is a basalt-free edifice that alternated rhyolitic and intermediate modes from 50ka to 2ka (largely contemporaneous with Middle Sister). Detailed mapping, 330 chemical analyses, and 42 radioisotopic ages show that the oldest exposed South Sister lavas were initially rhyolitic ~50ka. By ~37ka, rhyolitic lava flows and domes (72-74% SiO2) began alternating with radially emplaced dacite (63-68% SiO2) and andesite (59-63% SiO2) lava flows. Construction of a broad cone of silicic andesite-dacite (61-64% SiO2) culminated ~30ka in a dominantly explosive sequence that began with crater-forming andesitic eruptions that left fragmental deposits at least 200m thick. This was followed at ~27ka by growth of a steeply dipping summit cone of agglutinate-dominated andesite (56-60.5% SiO2) and formation of a summit crater ~800m wide. This crater was soon filled and overtopped by a thick dacite lava flow and then by >150m of dacitic pyroclastic ejecta. Small-volume dacite lavas (63-67% SiO2) locally cap the pyroclastic pile. A final sheet of mafic agglutinate (54-56% SiO2) - the most mafic product of South Sister - erupted from and drapes the small (300-m-wide) present-day summit crater, ending a summit-building sequence that lasted until ~22ka. A 20kyr-long-hiatus was broken by rhyolite eruptions that produced (1) the Rock Mesa coulee, tephra, and satellite domelets (73.5% SiO2) and (2) the Devils Chain of ~20 domes and short coulees (72.3-72.8% SiO2) from N-S vent alignments on South Sister's flanks. The compositional reversal from mafic summit agglutinate to recent rhyolites epitomizes the frequently changing compositional modes of the

  8. Quantum cascade lasers with an integrated polarization mode converter.

    PubMed

    Dhirhe, D; Slight, T J; Holmes, B M; Hutchings, D C; Ironside, C N

    2012-11-01

    We discuss the design, fabrication and characterization of waveguide polarization mode converters for quantum cascade lasers operating at 4.6 μm. We have fabricated a quantum cascade laser with integrated polarization mode converter that emits light of 69% Transverse Electrical (TE) polarization from one facet and 100% Transverse Magnetic (TM) polarization from the other facet. PMID:23187389

  9. RECONFIGURING POWER SYSTEMS TO MINIMIZE CASCADING FAILURES: MODELS AND ALGORITHMS

    SciTech Connect

    Bienstock, Daniel

    2014-04-11

    the main goal of this project was to develop new scientific tools, based on optimization techniques, with the purpose of controlling and modeling cascading failures of electrical power transmission systems. We have developed a high-quality tool for simulating cascading failures. The problem of how to control a cascade was addressed, with the aim of stopping the cascade with a minimum of load lost. Yet another aspect of cascade is the investigation of which events would trigger a cascade, or more appropriately the computation of the most harmful initiating event given some constraint on the severity of the event. One common feature of the cascade models described (indeed, of several of the cascade models found in the literature) is that we study thermally-induced line tripping. We have produced a study that accounts for exogenous randomness (e.g. wind and ambient temperature) that could affect the thermal behavior of a line, with a focus on controlling the power flow of the line while maintaining safe probability of line overload. This was done by means of a rigorous analysis of a stochastic version of the heat equation. we incorporated a model of randomness in the behavior of wind power output; again modeling an OPF-like problem that uses chance-constraints to maintain low probability of line overloads; this work has been continued so as to account for generator dynamics as well.

  10. Thermoelectrically cooled interband cascade laser for field measurements

    NASA Astrophysics Data System (ADS)

    Christensen, Lance E.; Mansour, Kamjou; Yang, Rui Q.

    2010-11-01

    The development of interband cascade lasers from concept to packaged devices is briefly reviewed. The application of a single-mode, mid-IR (3.27-μm) interband cascade laser packaged with a thermoelectric cooler for field measurements of methane and water is described.

  11. A simple model of global cascades on random networks

    PubMed Central

    Watts, Duncan J.

    2002-01-01

    The origin of large but rare cascades that are triggered by small initial shocks is a phenomenon that manifests itself as diversely as cultural fads, collective action, the diffusion of norms and innovations, and cascading failures in infrastructure and organizational networks. This paper presents a possible explanation of this phenomenon in terms of a sparse, random network of interacting agents whose decisions are determined by the actions of their neighbors according to a simple threshold rule. Two regimes are identified in which the network is susceptible to very large cascades—herein called global cascades—that occur very rarely. When cascade propagation is limited by the connectivity of the network, a power law distribution of cascade sizes is observed, analogous to the cluster size distribution in standard percolation theory and avalanches in self-organized criticality. But when the network is highly connected, cascade propagation is limited instead by the local stability of the nodes themselves, and the size distribution of cascades is bimodal, implying a more extreme kind of instability that is correspondingly harder to anticipate. In the first regime, where the distribution of network neighbors is highly skewed, it is found that the most connected nodes are far more likely than average nodes to trigger cascades, but not in the second regime. Finally, it is shown that heterogeneity plays an ambiguous role in determining a system's stability: increasingly heterogeneous thresholds make the system more vulnerable to global cascades; but an increasingly heterogeneous degree distribution makes it less vulnerable. PMID:16578874

  12. 36 CFR 7.66 - North Cascades National Park.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false North Cascades National Park. 7.66 Section 7.66 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.66 North Cascades National Park....

  13. 36 CFR 7.66 - North Cascades National Park.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false North Cascades National Park. 7.66 Section 7.66 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.66 North Cascades National Park....

  14. 36 CFR 7.66 - North Cascades National Park.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false North Cascades National Park. 7.66 Section 7.66 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.66 North Cascades National Park....

  15. 36 CFR 7.66 - North Cascades National Park.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false North Cascades National Park. 7.66 Section 7.66 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.66 North Cascades National Park....

  16. 36 CFR 7.66 - North Cascades National Park.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false North Cascades National Park. 7.66 Section 7.66 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.66 North Cascades National Park....

  17. Cascades for hydrogen isotope separation using metal hydrides

    SciTech Connect

    Hill, F.B.; Grzetic, V.

    1982-01-01

    Designs are presented for continuous countercurrent hydrogen isotope separation cascades based on the use of metal hydrides. The cascades are made up of pressure swing adsorption (PSA) or temperature swing adsorption (TSA) stages. The designs were evolved from consideration of previously conducted studies of the separation performance of four types of PSA and TSA processes.

  18. How Do Haloarchaea Synthesize Aromatic Amino Acids?

    PubMed Central

    Gulko, Miriam Kolog; Dyall-Smith, Mike; Gonzalez, Orland; Oesterhelt, Dieter

    2014-01-01

    Genomic analysis of H. salinarum indicated that the de novo pathway for aromatic amino acid (AroAA) biosynthesis does not follow the classical pathway but begins from non-classical precursors, as is the case for M. jannaschii. The first two steps in the pathway were predicted to be carried out by genes OE1472F and OE1475F, while the 3rd step follows the canonical pathway involving gene OE1477R. The functions of these genes and their products were tested by biochemical and genetic methods. In this study, we provide evidence that supports the role of proteins OE1472F and OE1475F catalyzing consecutive enzymatic reactions leading to the production of 3-dehydroquinate (DHQ), after which AroAA production proceeds via the canonical pathway starting with the formation of DHS (dehydroshikimate), catalyzed by the product of ORF OE1477R. Nutritional requirements and AroAA uptake studies of the mutants gave results that were consistent with the proposed roles of these ORFs in AroAA biosynthesis. DNA microarray data indicated that the 13 genes of the canonical pathway appear to be utilised for AroAA biosynthesis in H. salinarum, as they are differentially expressed when cells are grown in medium lacking AroAA. PMID:25216252

  19. Quantitation of Aristolochic Acids in Corn, Wheat Grain, and Soil Samples Collected in Serbia: Identifying a Novel Exposure Pathway in the Etiology of Balkan Endemic Nephropathy.

    PubMed

    Chan, Wan; Pavlović, Nikola M; Li, Weiwei; Chan, Chi-Kong; Liu, Jingjing; Deng, Kailin; Wang, Yinan; Milosavljević, Biljana; Kostić, Emina N

    2016-07-27

    While to date investigations provided convincing evidence on the role of aristolochic acids (AAs) in the etiology of Balkan endemic nephropathy (BEN) and upper urothelial cancer (UUC), the exposure pathways by which AAs enter human bodies to cause BEN and UUC remain obscure. The goal of this study is to test the hypothesis that environmental pollution by AAs and root uptake of AAs in the polluted soil may be one of the pathways by which AAs enter the human food chain. The hypothesis driving this study was that the decay of Aristolochia clematitis L., a AA-containing herbaceous plant that is found growing widespread in the endemic regions, could release free AAs to the soil, which could be taken up by food crops growing nearby, thereby transferring this potent human nephrotoxin and carcinogen into their edible parts. Using the highly sensitive and selective high-performance liquid chromatography coupled with fluorescence detection method, we identified and quantitated in this study for the first time AAs in corn, wheat grain, and soil samples collected from the endemic village Kutles in Serbia. Our results provide the first direct evidence that food crops and soil in the Balkans are contaminated with AAs. It is possible that the presence of AAs in edible parts of crops originating from the AA-contaminated soil could be one of the major pathways by which humans become exposed to AAs. PMID:27362729

  20. Arachidonic acid-mediated inhibition of a potassium current in the giant neurons of Aplysia

    SciTech Connect

    Carlson, R.O.

    1990-01-01

    Biochemical and electrophysiological approaches were used to investigate the role of arachidonic acid (AA) in the modulation of an inwardly rectifying potassium current (I{sub R}) in the giant neurons of the marine snail, Aplysia californica. Using ({sup 3}H)AA as tracer, the intracellular free AA pool in Aplysia ganglia was found to be in a state of constant and rapid turnover through deacylation and reacylation of phospholipid, primarily phosphatidyl-inositol. This constant turnover was accompanied by a constant release of free AA and eicosanoids into the extracellular medium. The effects of three pharmacological agents were characterized with regard to AA metabolism in Aplysia ganglia. 4-O-tetra-decanoylphorbol 13-acetate (TPA), an activator of protein kinase C, stimulated liberation of AA from phospholipid, and 4-bromophenacylbromide (BPB), an inhibitor of phospholipate A{sub 2}, inhibited this liberation. Indomethacin at 250 {mu}M was found to inhibit uptake of AA, likely through inhibition of acyl-CoA synthetase. These agents were also found to modulate I{sub R} in ways which were consistent with their biological effects: TPA inhibited I{sub R}, and both BPB and indomethacin stimulated I{sub R} . Modulation of I{sub R} by these substances was found not to involve cAMP metabolism. Acute application of exogenous AA did not affect I{sub R}; however, I{sub R} in giant neurons was found to be inhibited after dialysis with AA or other unsaturated fatty acids. Also, after perfusion with BSA overnight, a treatment which strips the giant neurons of AA in lipid storage, I{sub R} was found to have increased over 2-fold. This perfusion-induced increase was inhibited by the presence of AA or by pretreatment of the giant neurons with BPB. These results suggest AA, provided through constant turnover from phospholipid, mediates constitutive inhibition of I{sub R}.