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Sample records for derived methoxylated analog

  1. Stability of apigeninidin and its methoxylated derivatives in the presence of sulfites.

    PubMed

    Ojwang, Leonnard O; Awika, Joseph M

    2010-08-25

    3-Deoxyanthocyanin pigments are more stable than anthocyanins and show promising bioactive properties. However, little is known about their stability in the presence of food additives such as sulfites. This work investigates the stability of apigeninidin and its derivatives in the presence of sulfites. Pigment (apigeninidin, 5-mono-, and 5,7-dimethoxyapigeninidin) stability at pH 1.8, 3.0, and 5.0, in the presence of sodium metabisulfite (molar ratio ∼ 1:40, pigment/SO2) was monitored over 21 days at room temperature. The structure of sulfite complexation products was monitored using HPLC-MS and NMR spectroscopy. All pigments were significantly bleached within 30 min in the presence of sulfites; the bleaching effect was more severe at pH 5.0 and 3.0 compared to pH 1.8. Apigeninidin was more resistant to bleaching than its methoxylated derivatives. However, all pigments regained some or all of the bleached color within 14-21 days at pH 3.0 and 1.8 in the presence of sulfites, indicating equilibrium favored flavylium cation at these pH values. Formation of colorless sulfonates via bisulfite ion addition at C-4 was responsible for the bleaching effect. Both structure and pH significantly affected stability of 3-deoxyanthocyanidins in the presence of sulfites. The pigments may have potential applications in low pH systems containing sulfites.

  2. “One-shot” analysis of polybrominated diphenyl ethers and their hydroxylated and methoxylated analogs in human breast milk and serum using gas chromatography-tandem mass spectrometry

    PubMed Central

    Butryn, Deena; Gross, Michael; Chi, Lai-Har; Schecter, Arnold; Olson, James; Aga, Diana

    2015-01-01

    The presence of polybrominated diphenyl ethers (PBDEs) and their hydroxylated (OH-BDE) and methoxylated (MeO-BDE) analogs in humans is an area of high interest to public health due to their neurotoxic and endocrine disrupting effects. Consequently, there is a rise involving the investigation of these three classes of compounds together in order to understand their bioaccumulation patterns in environmental matrices and in humans. Analysis of PBDEs, OH-BDEs, and MeO-BDEs using liquid chromatography-mass spectrometry (LC-MS) can be accomplished simultaneously, but detection limits for PBDEs and MeO-BDEs in LC-MS is insufficient for trace level quantification. Therefore, fractionation steps of the phenolic (OH-BDEs) and neutral (PBDEs and MeO-BDEs) compounds during sample preparation are typically performed so different detection techniques can be used to achieve the needed sensitivities. However, this approach involves multiple injections, ultimately increasing analysis time. In this study, an analytical method was developed for a “one-shot” analysis of 12 PBDEs, 12 OH-BDEs, and 13 MeO-BDEs using gas chromatography tandem mass spectrometry (GC-MS/MS). This overall method includes simultaneous extraction of all analytes via pressurized liquid extraction followed by lipid removal steps to reduce matrix interferences. The OH-BDEs were derivatized using N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide, producing OH-TMDS derivatives that can be analyzed with PBDEs and MeO-BDEs by GC-MS/MS in “one shot” within a 25-min run. The overall recoveries were generally greater than 65%, and the limits of detection ranged from 2–14 pg in both breast milk and serum. The applicability of the method was successfully validated on four paired human breast milk and serum samples. The mean concentrations of total PBDEs, OH-BDEs, and MeO-BDEs in breast milk were 59, 2.2, and 0.57 ng g−1 lipid, respectively. In serum, the mean total concentrations were 79, 38, and 0.96 ng g

  3. "One-shot" analysis of polybrominated diphenyl ethers and their hydroxylated and methoxylated analogs in human breast milk and serum using gas chromatography-tandem mass spectrometry.

    PubMed

    Butryn, Deena M; Gross, Michael S; Chi, Lai-Har; Schecter, Arnold; Olson, James R; Aga, Diana S

    2015-09-10

    The presence of polybrominated diphenyl ethers (PBDEs) and their hydroxylated (OH-BDE) and methoxylated (MeO-BDE) analogs in humans is an area of high interest to scientists and the public due to their neurotoxic and endocrine disrupting effects. Consequently, there is a rise in the investigation of the occurrence of these three classes of compounds together in environmental matrices and in humans in order to understand their bioaccumulation patterns. Analysis of PBDEs, OH-BDEs, and MeO-BDEs using liquid chromatography-mass spectrometry (LC-MS) can be accomplished simultaneously, but detection limits for PBDEs and MeO-BDEs in LC-MS is insufficient for trace level quantification. Therefore, fractionation steps of the phenolic (OH-BDEs) and neutral (PBDEs and MeO-BDEs) compounds during sample preparation are typically performed so that different analytical techniques can be used to achieve the needed sensitivities. However, this approach involves multiple injections, ultimately increasing analysis time. In this study, an analytical method was developed for a "one-shot" analysis of 12 PBDEs, 12 OH-BDEs, and 13 MeO-BDEs using gas chromatography with tandem mass spectrometry (GC-MS/MS). This overall method includes simultaneous extraction of all analytes via pressurized liquid extraction followed by lipid removal steps to reduce matrix interferences. The OH-BDEs were derivatized using N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (TBDMS-MTFA), producing OH-TBDMS derivatives that can be analyzed together with PBDEs and MeO-BDEs by GC-MS/MS in "one shot" within a 25-min run time. The overall recoveries were generally higher than 65%, and the limits of detection ranged from 2 to 14 pg in both breast milk and serum matrices. The applicability of the method was successfully validated on four paired human breast milk and serum samples. The mean concentrations of total PBDEs, OH-BDEs, and MeO-BDEs in breast milk were 59, 2.2, and 0.57 ng g(-1) lipid, respectively. In

  4. 3,5,4′-Trimethoxystilbene, a natural methoxylated analog of resveratrol, inhibits breast cancer cell invasiveness by downregulation of PI3K/Akt and Wnt/β-catenin signaling cascades and reversal of epithelial–mesenchymal transition

    SciTech Connect

    Tsai, Jie-Heng; Hsu, Li-Sung; Lin, Chih-Li; Hong, Hui-Mei; Pan, Min-Hsiung; Way, Tzong-Der; Chen, Wei-Jen

    2013-11-01

    The molecular basis of epithelial–mesenchymal transition (EMT) functions as a potential therapeutic target for breast cancer because EMT may endow breast tumor-initiating cells with stem-like characteristics and enable the dissemination of breast cancer cells. We have recently verified the antitumor activity of 3,5,4′-trimethoxystilbene (MR-3), a naturally methoxylated derivative of resveratrol, in colorectal cancer xenografts via an induction of apoptosis. The effect of MR-3 on EMT and the invasiveness of human MCF-7 breast adenocarcinoma cell line were also explored. We found that MR-3 significantly increased epithelial marker E-cadherin expression and triggered a cobblestone-like morphology of MCF-7 cells, while reciprocally decreasing the expression of mesenchymal markers, such as snail, slug, and vimentin. In parallel with EMT reversal, MR-3 downregulated the invasion and migration of MCF-7 cells. Exploring the action mechanism of MR-3 on the suppression of EMT and invasion indicates that MR-3 markedly reduced the expression and nuclear translocation of β-catenin, accompanied with the downregulation of β-catenin target genes and the increment of membrane-bound β-catenin. These results suggest the involvement of Wnt/β-catenin signaling in the MR-3-induced EMT reversion of MCF-7 cells. Notably, MR-3 restored glycogen synthase kinase-3β activity by inhibiting the phosphorylation of Akt, the event required for β-catenin destruction via a proteasome-mediated system. Overall, these findings indicate that the anti-invasive activity of MR-3 on MCF-7 cells may result from the suppression of EMT via down-regulating phosphatidylinositol 3-kinase (PI3K)/AKT signaling, and consequently, β-catenin nuclear translocation. These occurrences ultimately lead to the blockage of EMT and the invasion of breast cancer cells. - Highlights: • MR-3 blocked MCF-7 cell invasion by inducing a reversal of EMT. • Wnt/β-catenin signaling is involved in MR-3-induced EMT

  5. Cross-Domain Analogies as Relating Derived Relations among Two Separate Relational Networks

    ERIC Educational Resources Information Center

    Ruiz, Francisco J.; Luciano, Carmen

    2011-01-01

    Contemporary behavior analytic research is making headway in analyzing analogy as the establishment of a relation of coordination among common types of trained or derived relations. Previous studies have been focused on within-domain analogy. The current study expands previous research by analyzing cross-domain analogy as relating relations among…

  6. Identification of pyridine analogs as new predator-derived kairomones

    PubMed Central

    Brechbühl, Julien; Moine, Fabian; Tosato, Monique Nenniger; Sporkert, Frank; Broillet, Marie-Christine

    2015-01-01

    In the wild, animals have developed survival strategies relying on their senses. The individual ability to identify threatening situations is crucial and leads to increase in the overall fitness of the species. Rodents, for example have developed in their nasal cavities specialized olfactory neurons implicated in the detection of volatile cues encoding for impending danger such as predator scents or alarm pheromones. In particular, the neurons of the Grueneberg ganglion (GG), an olfactory subsystem, are implicated in the detection of danger cues sharing a similar chemical signature, a heterocyclic sulfur- or nitrogen-containing motif. Here we used a “from the wild to the lab” approach to identify new molecules that are involuntarily emitted by predators and that initiate fear-related responses in the recipient animal, the putative prey. We collected urines from carnivores as sources of predator scents and first verified their impact on the blood pressure of the mice. With this approach, the urine of the mountain lion emerged as the most potent source of chemical stress. We then identified in this biological fluid, new volatile cues with characteristic GG-related fingerprints, in particular the methylated pyridine structures, 2,4-lutidine and its analogs. We finally verified their encoded danger quality and demonstrated their ability to mimic the effects of the predator urine on GG neurons, on mice blood pressure and in behavioral experiments. In summary, we were able to identify here, with the use of an integrative approach, new relevant molecules, the pyridine analogs, implicated in interspecies danger communication. PMID:26283896

  7. Identification of pyridine analogs as new predator-derived kairomones.

    PubMed

    Brechbühl, Julien; Moine, Fabian; Tosato, Monique Nenniger; Sporkert, Frank; Broillet, Marie-Christine

    2015-01-01

    In the wild, animals have developed survival strategies relying on their senses. The individual ability to identify threatening situations is crucial and leads to increase in the overall fitness of the species. Rodents, for example have developed in their nasal cavities specialized olfactory neurons implicated in the detection of volatile cues encoding for impending danger such as predator scents or alarm pheromones. In particular, the neurons of the Grueneberg ganglion (GG), an olfactory subsystem, are implicated in the detection of danger cues sharing a similar chemical signature, a heterocyclic sulfur- or nitrogen-containing motif. Here we used a "from the wild to the lab" approach to identify new molecules that are involuntarily emitted by predators and that initiate fear-related responses in the recipient animal, the putative prey. We collected urines from carnivores as sources of predator scents and first verified their impact on the blood pressure of the mice. With this approach, the urine of the mountain lion emerged as the most potent source of chemical stress. We then identified in this biological fluid, new volatile cues with characteristic GG-related fingerprints, in particular the methylated pyridine structures, 2,4-lutidine and its analogs. We finally verified their encoded danger quality and demonstrated their ability to mimic the effects of the predator urine on GG neurons, on mice blood pressure and in behavioral experiments. In summary, we were able to identify here, with the use of an integrative approach, new relevant molecules, the pyridine analogs, implicated in interspecies danger communication. PMID:26283896

  8. Cross-Domain Analogies as Relating Derived Relations among Two Separate Relational Networks

    PubMed Central

    Ruiz, Francisco J; Luciano, Carmen

    2011-01-01

    Contemporary behavior analytic research is making headway in analyzing analogy as the establishment of a relation of coordination among common types of trained or derived relations. Previous studies have been focused on within-domain analogy. The current study expands previous research by analyzing cross-domain analogy as relating relations among separate relational networks and by correlating participants' performance with a standard measure of analogical reasoning. In two experiments, adult participants first completed general intelligence and analogical reasoning tests. Subsequently, they were exposed to a computerized conditional discrimination training procedure designed to create two relational networks, each consisting of two 3-member equivalence classes. The critical test was a two-part analogical test in which participants had to relate combinatorial relations of coordination and distinction between the two relational networks. In Experiment 1, combinatorial relations for each network were individually tested prior to analogical testing, but in Experiment 2 they were not. Across both experiments, 65% of participants passed the analogical test on the first attempt. Moreover, results from the training procedure were strongly correlated with the standard measure of analogical reasoning. PMID:21547072

  9. Relating Derived Relations as a Model of Analogical Reasoning: Reaction Times and Event-Related Potentials

    ERIC Educational Resources Information Center

    Barnes-Holmes, Dermot; Regan, Donal; Barnes-Holmes, Yvonne; Commins, Sean; Walsh, Derek; Stewart, Ian; Smeets, Paul M.; Whelan, Robert; Dymond, Simon

    2005-01-01

    The current study aimed to test a Relational Frame Theory (RFT) model of analogical reasoning based on the relating of derived same and derived difference relations. Experiment 1 recorded reaction time measures of similar-similar (e.g., "apple is to orange as dog is to cat") versus different-different (e.g., "he is to his brother as chalk is to…

  10. A review on plant-derived natural products and their analogs with anti-tumor activity

    PubMed Central

    Dholwani, K.K.; Saluja, A.K.; Gupta, A.R.; Shah, D.R.

    2008-01-01

    Traditional medicines, including Chinese herbal formulations, can serve as the source of potential new drugs, and initial research focuses on the isolation of bioactive lead compound(s). The development of novel plant-derived natural products and their analogs for anticancer activity details efforts to synthesize new derivatives based on bioactivity- and mechanism of action-directed isolation and characterization coupled with rational drug design - based modification. Also, the anticancer activity of certain natural products and their analogs can be enhanced by synthesizing new derivatives based on active pharmacophore models; drug resistance and solubility and metabolic limitations can be overcome by appropriate molecular modifications; and new biological properties or mechanisms of action can be added by combining other functional groups or molecules. Preclinical screening for in vitro human cell line panels and selected in vivo xenograft testing then identifies the most promising drug development targets. PMID:21279166

  11. δ²H, δ¹³C and δ¹⁸O from whole wood, α-cellulose and lignin methoxyl groups in Pinus sylvestris: a multi-parameter approach.

    PubMed

    Mischel, Maria; Esper, Jan; Keppler, Frank; Greule, Markus; Werner, Willy

    2015-01-01

    Novel tree ring parameters - δ(13)C and δ(2)H from methoxyl groups - have been developed to reconstruct palaeoclimate. Tests with δ(13)C and δ(18)O derived from whole wood and cellulose samples, however, indicated differences in the isotopic composition and climate signal, depending on the extracted wood component. We assess this signal dependency by analysing (i) δ(13)C and δ(18)O from whole wood and cellulose and (ii) δ(13)C and δ(2)H from methoxyl groups, using Pinus sylvestris L. growing near Altenkirchen (Germany). Results indicate significant correlations among the time series derived from whole wood, cellulose, and lignin methoxyl groups. Compared with the whole wood samples, δ(13)C from methoxyl groups showed a different and overall lower response to climate parameters. On the other hand, δ(2)H from methoxyl groups showed high correlations with temperature and was also correlated with ring width, indicating its potential as a temperature proxy. Isotope time series with the highest correlation with climatic parameter were: (i) whole wood and cellulose δ(13)C with growing season precipitation and summer temperature; (ii) methoxyl groups with spring precipitation; (iii) whole wood and cellulose δ(18)O correlates with annual evapotranspiration and water balance; and (iv) methoxyl group δ(2)H with spring temperatures. These findings reveal that multiple climate elements can be reconstructed from different wood components and that whole wood proxies perform comparably to cellulose time series.

  12. δ²H, δ¹³C and δ¹⁸O from whole wood, α-cellulose and lignin methoxyl groups in Pinus sylvestris: a multi-parameter approach.

    PubMed

    Mischel, Maria; Esper, Jan; Keppler, Frank; Greule, Markus; Werner, Willy

    2015-01-01

    Novel tree ring parameters - δ(13)C and δ(2)H from methoxyl groups - have been developed to reconstruct palaeoclimate. Tests with δ(13)C and δ(18)O derived from whole wood and cellulose samples, however, indicated differences in the isotopic composition and climate signal, depending on the extracted wood component. We assess this signal dependency by analysing (i) δ(13)C and δ(18)O from whole wood and cellulose and (ii) δ(13)C and δ(2)H from methoxyl groups, using Pinus sylvestris L. growing near Altenkirchen (Germany). Results indicate significant correlations among the time series derived from whole wood, cellulose, and lignin methoxyl groups. Compared with the whole wood samples, δ(13)C from methoxyl groups showed a different and overall lower response to climate parameters. On the other hand, δ(2)H from methoxyl groups showed high correlations with temperature and was also correlated with ring width, indicating its potential as a temperature proxy. Isotope time series with the highest correlation with climatic parameter were: (i) whole wood and cellulose δ(13)C with growing season precipitation and summer temperature; (ii) methoxyl groups with spring precipitation; (iii) whole wood and cellulose δ(18)O correlates with annual evapotranspiration and water balance; and (iv) methoxyl group δ(2)H with spring temperatures. These findings reveal that multiple climate elements can be reconstructed from different wood components and that whole wood proxies perform comparably to cellulose time series. PMID:26156050

  13. Biomonitoring of human exposures to chlorinated derivatives and structural analogs of bisphenol A.

    PubMed

    Andra, Syam S; Charisiadis, Pantelis; Arora, Manish; van Vliet-Ostaptchouk, Jana V; Makris, Konstantinos C

    2015-12-01

    The high reactivity of bisphenol A (BPA) with disinfectant chlorine is evident in the instantaneous formation of chlorinated BPA derivatives (ClxBPA) in various environmental media that show increased estrogen-activity when compared with that of BPA. The documented health risks associated with BPA exposures have led to the gradual market entry of BPA structural analogs, such as bisphenol S (BPS), bisphenol F (BPF), bisphenol B (BPB), etc. A suite of exposure sources to ClxBPA and BPA analogs in the domestic environment is anticipated to drive the nature and range of halogenated BPA derivatives that can form when residual BPA comes in contact with disinfectant in tap water and/or consumer products. The primary objective of this review was to survey all available studies reporting biomonitoring protocols of ClxBPA and structural BPA analogs (BPS, BPF, BPB, etc.) in human matrices. Focus was paid on describing the analytical methodologies practiced for the analysis of ClxBPA and BPA analogs using hyphenated chromatography and mass spectrometry techniques, because current methodologies for human matrices are complex. During the last decade, an increasing number of ecotoxicological, cell-culture and animal-based and human studies dealing with ClxBPA exposure sources and routes of exposure, metabolism and toxicity have been published. Up to date findings indicated the association of ClxBPA with metabolic conditions, such as obesity, lipid accumulation, and type 2 diabetes mellitus, particularly in in-vitro and in-vivo studies. We critically discuss the limitations, research needs and future opportunities linked with the inclusion of ClxBPA and BPA analogs into exposure assessment protocols of relevant epidemiological studies. PMID:26521216

  14. Biomonitoring of human exposures to chlorinated derivatives and structural analogs of bisphenol A.

    PubMed

    Andra, Syam S; Charisiadis, Pantelis; Arora, Manish; van Vliet-Ostaptchouk, Jana V; Makris, Konstantinos C

    2015-12-01

    The high reactivity of bisphenol A (BPA) with disinfectant chlorine is evident in the instantaneous formation of chlorinated BPA derivatives (ClxBPA) in various environmental media that show increased estrogen-activity when compared with that of BPA. The documented health risks associated with BPA exposures have led to the gradual market entry of BPA structural analogs, such as bisphenol S (BPS), bisphenol F (BPF), bisphenol B (BPB), etc. A suite of exposure sources to ClxBPA and BPA analogs in the domestic environment is anticipated to drive the nature and range of halogenated BPA derivatives that can form when residual BPA comes in contact with disinfectant in tap water and/or consumer products. The primary objective of this review was to survey all available studies reporting biomonitoring protocols of ClxBPA and structural BPA analogs (BPS, BPF, BPB, etc.) in human matrices. Focus was paid on describing the analytical methodologies practiced for the analysis of ClxBPA and BPA analogs using hyphenated chromatography and mass spectrometry techniques, because current methodologies for human matrices are complex. During the last decade, an increasing number of ecotoxicological, cell-culture and animal-based and human studies dealing with ClxBPA exposure sources and routes of exposure, metabolism and toxicity have been published. Up to date findings indicated the association of ClxBPA with metabolic conditions, such as obesity, lipid accumulation, and type 2 diabetes mellitus, particularly in in-vitro and in-vivo studies. We critically discuss the limitations, research needs and future opportunities linked with the inclusion of ClxBPA and BPA analogs into exposure assessment protocols of relevant epidemiological studies.

  15. High performance liquid chromatography enantioseparation of the novel designed mexiletine derivatives and its analogs.

    PubMed

    Zheng, Chengzhen; Zhang, Datong; Wu, Qi; Lin, Xianfu

    2011-02-01

    A series of novel designed mexiletine derivatives and its analogs were prepared, the structures were confirmed by Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR), and Electrospray Ionization-Mass Spectrometry (ESI-MS), and the enantioseparations were performed on polysaccharide-based chiral stationary phase (CSP), Chiralcel OD-H, and Chiralcel OJ-H, under normal-phase mode. The effects of the concentration of isopropanol in the mobile phase were studied, seven of the eight enantiomers got baseline separation on Chiralcel OD-H, and five of the eight enantiomers got successfully separation on Chiralcel OJ-H. The effects of structural features were also discussed. PMID:20544701

  16. Diazaquinomycins E–G, Novel Diaza-Anthracene Analogs from a Marine-Derived Streptomyces sp.

    PubMed Central

    Mullowney, Michael W.; Ó hAinmhire, Eoghainín; Shaikh, Anam; Wei, Xiaomei; Tanouye, Urszula; Santarsiero, Bernard D.; Burdette, Joanna E.; Murphy, Brian T.

    2014-01-01

    As part of our program to identify novel secondary metabolites that target drug-resistant ovarian cancers, a screening of our aquatic-derived actinomycete fraction library against a cisplatin-resistant ovarian cancer cell line (OVCAR5) led to the isolation of novel diaza-anthracene antibiotic diazaquinomycin E (DAQE; 1), the isomeric mixture of diazaquinomycin F (DAQF; 2) and diazaquinomycin G (DAQG; 3), and known analog diazaquinomycin A (DAQA; 4). The structures of DAQF and DAQG were solved through deconvolution of X-Ray diffraction data of their corresponding co-crystal. DAQE and DAQA exhibited moderate LC50 values against OVCAR5 of 9.0 and 8.8 μM, respectively. At lethal concentrations of DAQA, evidence of DNA damage was observed via induction of apoptosis through cleaved-PARP. Herein, we will discuss the isolation, structure elucidation, and biological activity of these secondary metabolites. PMID:24921978

  17. Methoxylated polybrominated diphenyl ethers (MeO-PBDE) in human milk from Bizerte, Tunisia.

    PubMed

    Ben Hassine, Sihem; Ben Ameur, Walid; Eljarrat, Ethel; Barceló, Damià; Touil, Soufiane; Driss, Mohamed Ridha

    2015-04-01

    Methoxylated polybrominated diphenyl ethers (MeO-PBDEs) were determined in 36 human milk samples collected in 2010 from healthy mothers living in Bizerte region from Tunisia. Gas chromatography coupled to mass spectrometry working with negative ion chemical ionization (GC-NCI-MS) was used to identify and quantify residue levels on a lipid basis of organo-brominated compounds. Among the 8 examined MeO-PBDE congeners 6-MeO-BDE-47, 2'-MeO-BDE-68, 4'-MeO-BDE-49 and 5'-MeO-BDE-100 were detected in human milk at different levels and frequencies. This is the first study reporting 5'-MeO-BDE-100 and 4'-MeO-BDE-49 levels in human milk samples. Levels of ∑MeO-PBDEs ranged from 0.23 to 4.70ngg(-)(1) lipid weight (lw) in the samples, with a mean and median value of 1.52 and 1.11ngg(-1)lw respectively. Concentrations of ∑MeO-PBDEs in human milk were negatively correlated with age of primapara mothers (p<0.05) and no age-dependency was observed for multipara mothers. Primapara mothers had higher levels of MeO-PBDEs than multipara mothers however no statistical significance was observed. A weak correlation between ∑PBDEs and ∑MeO-PBDEs was found but not between BDE-47 and its methoxylated analog 6-MeO-BDE-47, suggesting differences in exposure pathways for these contaminants in humans and further supporting the hypothesis that MeO-PBDEs were likely not only originated from PBDE precursors.

  18. Methoxylated polybrominated diphenyl ethers (MeO-PBDE) in human milk from Bizerte, Tunisia.

    PubMed

    Ben Hassine, Sihem; Ben Ameur, Walid; Eljarrat, Ethel; Barceló, Damià; Touil, Soufiane; Driss, Mohamed Ridha

    2015-04-01

    Methoxylated polybrominated diphenyl ethers (MeO-PBDEs) were determined in 36 human milk samples collected in 2010 from healthy mothers living in Bizerte region from Tunisia. Gas chromatography coupled to mass spectrometry working with negative ion chemical ionization (GC-NCI-MS) was used to identify and quantify residue levels on a lipid basis of organo-brominated compounds. Among the 8 examined MeO-PBDE congeners 6-MeO-BDE-47, 2'-MeO-BDE-68, 4'-MeO-BDE-49 and 5'-MeO-BDE-100 were detected in human milk at different levels and frequencies. This is the first study reporting 5'-MeO-BDE-100 and 4'-MeO-BDE-49 levels in human milk samples. Levels of ∑MeO-PBDEs ranged from 0.23 to 4.70ngg(-)(1) lipid weight (lw) in the samples, with a mean and median value of 1.52 and 1.11ngg(-1)lw respectively. Concentrations of ∑MeO-PBDEs in human milk were negatively correlated with age of primapara mothers (p<0.05) and no age-dependency was observed for multipara mothers. Primapara mothers had higher levels of MeO-PBDEs than multipara mothers however no statistical significance was observed. A weak correlation between ∑PBDEs and ∑MeO-PBDEs was found but not between BDE-47 and its methoxylated analog 6-MeO-BDE-47, suggesting differences in exposure pathways for these contaminants in humans and further supporting the hypothesis that MeO-PBDEs were likely not only originated from PBDE precursors. PMID:25682256

  19. Synthesis of new N-analogous corollosporine derivatives with antibacterial activity by laccase-catalyzed amination.

    PubMed

    Mikolasch, Annett; Hessel, Susanne; Salazar, Manuela Gesell; Neumann, Helfried; Manda, Katrin; Gōrdes, Dirk; Schmidt, Enrico; Thurow, Kerstin; Hammer, Elke; Lindequist, Ulrike; Beller, Matthias; Schauer, Frieder

    2008-06-01

    Corollosporine isolated from the marine fungus Corollospora maritima and N-analogous corollosporines are antimicrobial substances. Owing to the basic structure of the N-analogous corollosporines, they have become an attractive target for laccase-catalyzed derivatisation. In this regard we report on the straightforward laccase-catalyzed amination of dihydroxylated arenes with N-analogous corollosporines. In biological assays the obtained amination products are more active than the parent compounds.

  20. Characterization of the global structure of low methoxyl pectin in solution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Low methoxyl citrus pectin (LMP) and amidated low methoxyl pectin (LMAP) were characterized by high performance size exclusion chromatography (HPSEC) with online light scattering (LS), intrinsic viscosity ('w), differential refractive index (dRI) and ultra violet detection (UV), by amino acid anal...

  1. D/H ratios of methoxyl groups of the sedimentary organic matter of Lake Holzmaar (Eifel, Germany): A potential palaeoclimate/-hydrology proxy

    NASA Astrophysics Data System (ADS)

    Anhäuser, Tobias; Sirocko, Frank; Greule, Markus; Esper, Jan; Keppler, Frank

    2014-10-01

    Stable hydrogen isotope ratios (δD values) of methoxyl groups in lignin and pectin from a variety of plant types from different locations have been shown to mirror δD values of precipitation, with a mean uniform isotopic fractionation. Since δD in precipitation is mainly influenced by climatic conditions, including temperature, evaporation and precipitation amount, methoxyl groups of organic matter have been proposed as a potential palaeoclimate proxy. Here, we measured the δD values of the methoxyl groups of sedimentary organic matter derived from sediment core segments of Lake Holzmaar (Eifel, Germany). The sediment core covers the entire Holocene and part of the Late Glacial (until 13,650 years BP). Since the sedimentary organic matter was indicated by organic source proxies of predominantly phytoplanktonic origin, we considered the δD values of the methoxyl groups as a proxy for the δD value of the lake water. Presently and probably during most of the Holocene, the δD value of precipitation was primarily controlled by temperature (2-4.5‰/°C) as well as in isotopic equilibrium with the δD value of the lake water. We used these modern temperature sensitivities of the Eifel region together with the measured δD values of the methoxyl groups of the sedimentary organic matter to evaluate temperature changes recorded for the Holocene. The resulting mean temperature variance was found to be consistently less than 1.8-4 °C and is broadly in line with that reported from the NGRIP ice core for the same period. The transition from the Holocene to the Late Glacial period was accompanied with more negative δD values of the methoxyl groups (∼13‰ for the Younger Dryas). Besides the association with temperature we assumed a higher susceptibility of the δD value of Lake Holzmaar to evaporative enrichment during the Younger Dryas which could serve as an explanation for discrepancies reported for existing palaeoclimate/-hydrology records of the Eifel region. Our

  2. Lignin methoxyl hydrogen isotope ratios in a coastal ecosystem

    NASA Astrophysics Data System (ADS)

    Feakins, Sarah J.; Ellsworth, Patricia V.; Sternberg, Leonel da Silveira Lobo

    2013-11-01

    Stable hydrogen isotope ratios of plant lignin methoxyl groups have recently been shown to record the hydrogen isotopic composition of meteoric water. Here we extend this technique towards tracing water source variations across a saltwater to freshwater gradient in a coastal, subtropical forest ecosystem. We measure the hydrogen isotopic composition of xylem water (δDxw) and methoxyl hydrogen (δDmethoxyl) to calculate fractionations for coastal mangrove, buttonwood and hammock tree species in Sugarloaf Key, as well as buttonwoods from Miami, both in Florida, USA. Prior studies of the isotopic composition of cellulose and plant leaf waxes in coastal ecosystems have yielded only a weak correlation to source waters, attributed to leaf water effects. Here we find δDmethoxyl values range from -230‰ to -130‰, across a 40‰ range in δDxw with a regression equation of δDmethoxyl ‰ = 1.8 * δDxw - 178‰ (R2 = 0.48, p < 0.0001, n = 74). This is comparable within error to the earlier published relationship for terrestrial trees which was defined across a much larger 125‰ isotopic range in precipitation. Analytical precision for measurements of δD values of pure CH3I by gas chromatography-pyrolysis-isotope ratio mass spectrometry (GC-P-IRMS) is σ = 6‰ (n = 31), which is considerably better than for CH3I liberated through cleavage with HI from lignin with σ = 18‰ (n = 26). Our results establish that δDmethoxyl can record water sources and salinity incursion in coastal ecosystems, where variations sufficiently exceed method uncertainties (i.e., applications with δD excursions >50‰). For the first time, we also report yields of propyl iodide, which may indicate lignin synthesis of propoxyl groups under salt-stress.

  3. Glucosamine and Glucosamine-6-phosphate Derivatives: Catalytic Cofactor Analogs for the glmS Ribozyme

    PubMed Central

    Posakony, Jeffrey J.; Ferré-D'Amaré, Adrian R.

    2013-01-01

    Two analogues of glucosamine-6-phosphate (GlcN6P, 1) and five of glucosamine (GlcN, 2) were prepared for evaluation as catalytic cofactor of the glmS ribozyme, a bacterial gene-regulatory RNA that controls cell wall biosynthesis. Glucosamine and allosamine with 3-azido substitutions were prepared by SN2 reactions of the respective 1,2,4,6-protected sugars; final acidic hydrolysis afforded the fully deprotected compounds as their TFA salts. A 6-phospho-2-aminoglucolactam (31) was prepared from glucosamine in a 13-step synthesis, which included a late-stage POCl3-phosphorylation. A simple and widely applicable 2-step procedure with the triethylsilyl (TES) protecting group was developed to selectively expose the 6-OH group in N-protected glucosamine analogs, which provided another route to chemical phosphorylation. Mitsunobu chemistry afforded 6-cyano (35) and 6-azido (36) analogues of GlcN-(Cbz) and the selectivity for the 6-position was confirmed by NMR (COSY, HMBC, HMQC) experiments. Compound 36 was converted to the fully deprotected 6-azido-GlcN (37) and 2,6-diaminoglucose (38) analogs. A 2-hydroxylamino glucose (42) analogue was prepared via an oxaziridine (41). Enzymatic phosphorylation of 42 and chemical phosphorylation of its 6-OH precursor (43) were possible, but 42 and the 6-phospho product (44) were unstable under neutral or basic conditions. Chemical phosphorylation of the previously described 2-guanidinyl-glucose (46) afforded its 6-phospho analogue (49) after final deprotection. PMID:23578404

  4. Tracing the geographical origin of early potato tubers using stable hydrogen isotope ratios of methoxyl groups.

    PubMed

    Keppler, Frank; Hamilton, John T G

    2008-12-01

    The application of stable isotope ratio measurements has become an extremely useful tool for tracing the provenance of food products, thus ensuring that consumers receive products which comply with their labelled specifications. Recently, it has been shown that relative stable hydrogen isotope abundances (delta(2)H values) of wood lignin methoxyl groups have a distinct range that reflects the delta(2)H values of their meteoric source water. Furthermore, it has been suggested that the isotope information stored in methoxyl groups in plant matter generally might assist with determining the place of origin of plant material. We now have measured delta(2)H values of methoxyl groups from natural compounds in tubers of early potatoes (Solanum tuberosum) grown in different geographical locations. Tubers of early potatoes were collected from across Europe and regions close to the Mediterranean Sea between April and July 2004. The methoxyl groups from the potatoes were found to be highly depleted in (2)H, relative to both their meteoric water and bulk biomass, and a systematic shift of the delta(2)H values between methoxyl groups and meteoric water was observed. A constant fractionation of-161+/-11 per thousand. between methoxyl groups and modelled meteoric water is shown over a transaction covering the delta(2)H values of meteoric water from-95 per thousand in Northern Sweden to+25 per thousand in Egypt. From this information, early potato tubers from Middle Europe can be clearly distinguished from those of Mediterranean regions and from Northern Europe. Thus, we suggest that delta(2)H values of methoxyl groups have the potential to become an effective tool in assisting with the constraint of the geographical origin of potato tubers and other food stuffs.

  5. Synthesis and antitubercular activity of a series of hydrazone and nitrovinyl analogs derived from heterocyclic aldehydes.

    PubMed

    Sonar, Vijayakumar N; Crooks, Peter A

    2009-02-01

    A series of hydrazone and 3-nitrovinyl analogs of indole-3-carboxaldehydes and related compounds were synthesized and screened for antitubercular activity against Mycobacterium tuberculosis H37R(V) in BACTEC 12B medium using the Microplate Alamar Blue Assay (MABA). Several compounds showed inhibitory activity against M. tuberculosis in primary screening assays at a concentration of 6.25 microg/mL; subsequent dose-response studies indicated that the most active compounds, 3d, 3e & 8b, had IC(50) values of 5.96, 5.4 & 1.6 microg/mL, respectively. These compounds represent potential leads for the further development of novel antitubercular agents.

  6. Enhancing Physicochemical Properties through Synthesis and Formulation of Piclamilast- and Lapatinib-Derived Analogs

    NASA Astrophysics Data System (ADS)

    Woodring, Jennifer L.

    Human African trypanosomiasis (HAT) is a neglected tropical disease of significant morbidity and mortality in sub-Saharan Africa. Current chemotherapeutics targeting the causative agent Trypanosoma brucei lack oral bioavailability, efficacy, and safety. New small molecule drugs are desperately needed for HAT. Target repurposing represents one method for rapidly discovering new anti-trypanosomal compounds. This concept has been applied to repurposing small molecule inhibitors of human phosphodiesterases (PDEs) and protein tyrosine kinases (PTKs) for HAT, while improving physicochemical properties. The first project in this dissertation begins with the human PDE4 inhibitor piclamilast, which has an IC50 value of 4.7 microM against T. brucei PDEB1. Based upon this scaffold, new analogs were designed, synthesized, and screened for their biological activity against TbrPDEB1. Secondly, previous optimization of the human tyrosine kinase inhibitor lapatinib led to the discovery of the 4-anilino-quinazoline NEU-617, a potent (EC 50 = 42 nM) antitrypanosomal agent. Since alkynyl thienopyrimidines are well-known scaffolds for tyrosine kinase inhibitors, we assessed this scaffold as an alternative to the quinazoline of NEU-617. In addition, analogs of the NEU-617 were designed and synthesized to improve their physicochemical properties, such as lipophilicity and predicted central nervous system penetration. Lastly, nanoformulations have been shown to improve the oral bioavailability and circulation half-life of their encapsulated drug components. Because of this, nanoemulsions, liposomes, and polymeric nanoparticles were explored for their potential parasitic inhibitory effects and their ability to improve the physicochemical properties of NEU-617.

  7. Sugar and Sugar Derivatives in Residues Produced from the UV Irradiation of Astrophysical Ice Analogs

    NASA Technical Reports Server (NTRS)

    Nuevo, M.; Sandford, S. A.; Cooper, G.

    2016-01-01

    A large variety and number of organic compounds of prebiotic interest are known to be present in carbonaceous chondrites. Among them, one sugar (dihydroxyacetone) as well as several sugar acids, sugar alcohols, and other sugar derivatives have been reported in the Murchison and Murray meteorites. Their presence, along with amino acids, amphiphiles, and nucleobases strongly suggests that molecules essential to life can form abiotically under astrophysical conditions. This hypothesis is supported by laboratory studies on the formation of complex organic molecules from the ultraviolet (UV) irradiation of simulated astrophysical ice mixtures consisting of H2O, CO, CO2, CH3OH, CH4, NH3, etc., at low temperature. In the past 15 years, these studies have shown that the organic residues recovered at room temperature contain amino acids, amphiphiles, nucleobases, as well as other complex organics. However, no systematic search for the presence of sugars and sugar derivatives in laboratory residues have been reported to date, despite the fact that those compounds are of primary prebiotic significance. Indeed, only small (up to 3 carbon atoms) sugar derivatives including glycerol and glyceric acid have been detected in residues so far.

  8. Synthesis and radioprotective effects of derivatives of thiadiazoles, dithiolidenes, and their selenium analogs

    SciTech Connect

    Petrova, L.L.; Trufanova, L.V.; Petrov, M.L.; Abramov, M.A.; Zmitrovich, N.I.; Terent`eva, N.A.

    1994-12-01

    Derivatives of the sulfur-containing five-membered heterocyclic ring compounds, the 1,2,3-thiadiazoles, 1,3,4-thiodiazole, and 1,3-dithio-2-ylidenes, have a wide spectrum of biological activity. Studies of the radioprotective effects of sulfur-containing five-membered heterocyclic ring compounds have revealed such properties among a number of thiazoles. A number of heterocyclic selenium derivatives have also been shown to have radioactive properties. We report here the synthesis of 4-aryl-1,2,3-thia(selena)diazoles, 2-dialkylamino-1,3,4-thia(selena)diazolines, 2-benzylidene-1,3,4-thia(selena)diazolines, and 2-arylidene-1,3-dithio(selena)ols and the study of the toxic and radioprotective properties of these heterocyclic compounds on mice. These studies have demonstrated a relationship between the toxicity of the heterocyclic compounds and the presence of a selenium atom in the ring, without finding radioprotective properties among these five-membered, sulfur-, selenium-, and nitrogen-containing hetercyclic ring compounds, with the exception of 2-arylidene-1,3-dithiol. 9 refs., 3 tabs.

  9. The structure of high-methoxyl sugar acid gels of citrus pectin as determined by AFM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Images of native high methoxyl sugar acid gels (HMSAG) were obtained by atomic force microscopy (AFM) in the Tapping ModeTM. Electronic thinning of the pectin strands to one pixel wide allowed the pectin network to be viewed in the absence of variable strand widths related to preferentially solvate...

  10. Chloroethyinitrosourea-derived ethano cytosine and adenine adducts are substrates for escherichia coli glycosylases excising analogous etheno adducts

    SciTech Connect

    Guliaev, Anton B.; Singer, B.; Hang, Bo

    2004-05-05

    Exocyclic ethano DNA adducts are saturated etheno ring derivatives formed mainly by therapeutic chloroethylnitrosoureas (CNUs), which are also mutagenic and carcinogenic. In this work, we report that two of the ethano adducts, 3,N{sup 4}-ethanocytosine (EC) and 1,N{sup 6}-ethanoadenine (EA), are novel substrates for the Escherichia coli mismatch-specific uracil-DNA glycosylase (Mug) and 3-methyladenine DNA glycosylase II (AlkA), respectively. It has been shown previously that Mug excises 3,N{sup 4}-ethenocytosine ({var_epsilon}C) and AlkA releases 1,N{sup 6}-ethenoadenine ({var_epsilon}A). Using synthetic oligonucleotides containing a single ethano or etheno adduct, we found that both glycosylases had a {approx}20-fold lower excision activity toward EC or EA than that toward their structurally analogous {var_epsilon}C or {var_epsilon}A adduct. Both enzymes were capable of excising the ethano base paired with any of the four natural bases, but with varying efficiencies. The Mug activity toward EC could be stimulated by E. coli endonuclease IV and, more efficiently, by exonuclease III. Molecular dynamics (MD) simulations showed similar structural features of the etheno and ethano derivatives when present in DNA duplexes. However, also as shown by MD, the stacking interaction between the EC base and Phe 30 in the Mug active site is reduced as compared to the {var_epsilon}C base, which could account for the lower EC activity observed in this study.

  11. A non-invasive method for estimating heat flux out of a hydrothermal crack derived from fluid dynamics analog modeling

    NASA Astrophysics Data System (ADS)

    Barreyre, T.; Davaille, A.; Mittelstaedt, E. L.; Small, C.

    2015-12-01

    Direct observations of sub-surface flow parameters and processes at mid-ocean ridge hydrothermal systems are difficult to perform, which makes it challenging to estimate the associated flow parameters such as velocity or heat flux. Analog modeling of hydrothermal processes can act as a means to estimate these important hydrothermal parameters, as well as to explore the sensitivity and response of these systems to natural perturbations. In this study, we conduct analog experiments that focus on low-temperature hydrothermal outflow from linear cracks, which can account for a sizeable proportion of the total hydrothermal flux (up to 90% at certain hydrothermal fields). We approximate these cracks in the laboratory as an ideal heat source with a linear geometry, which release a continuous flow of hot material. So far, fluid dynamics studies have documented the linear and weakly non-linear convective regimes in this configuration, namely the rise of a laminar sheet of fluid above the linear heat source, and the eventual onset of oscillations. However, direct observations above cracks suggest the existence of 3D instabilities such as plumes. We therefore have undertaken a laboratory study to investigate the conditions of existence and the characteristics (velocity and temperature) of these 3D instabilities. The latter are indeed observed for all the experimental conditions we tested, but at different depths in the water column. Scaling laws relating the frequency and velocity of these 3D perturbations in the water column to the thermal characteristics of the crack (heat flux, temperature difference with the ambient fluid) were derived. Hence it become possible to infer the heat flux out of a linear hydrothermal crack from the observation of the instable flow above it by standard video-imagery from deep-sea vehicles. Such a non-invasive method would be a valuable tool for hydrothermal fields studies.

  12. Derivative multiple reaction monitoring and single herb calibration approach for multiple components quantification of traditional Chinese medicine analogous formulae.

    PubMed

    Li, Zhenhao; Xiao, Shun; Ai, Ni; Luo, Kedi; Fan, Xiaohui; Cheng, Yiyu

    2015-01-01

    In comparison with monotherapy in western medicine, traditional Chinese medicine (TCM) advocates combinational therapy for treating diseases and TCM formula is a representative for this approach. Despite of extensive clinical applications of TCM formulae, knowledge about their pharmacological activities, mechanisms of action and cellular targets remains limited. A main contributing factor to these unanswered questions is unavailability of chemical compositions and their contents in the formulae. Several challenges hinder global qualitative and quantitative analysis of the formulae, including large quantities of constituents, potential physicochemical changes during decoction and lack of authentic standards. Herein we introduced an integrated strategy based on liquid chromatography coupled with mass spectrometry (LC-MS) systems to address such challenges. First, liquid chromatography-ion trap and quadrupole time-of-flight mass spectrometry (LC-IT/MS and LC-QTOF/MS) were utilized to characterize chemical profiling of the formulae. Meanwhile, MS(2) of IT/MS produced major parameters for derivative multiple reaction monitoring (DeMRM) on liquid chromatography-triple quadrupole mass spectrometry (LC-TQ/MS), which offered rapid and direct transition design in the quantitative assay. Instead of authentic standards, serial dilutions of single herbs were employed in this study to construct calibration curves necessary for calculating relative concentrations of components. Xiao-Banxia decoction and its four analogous formulae were then taken to exemplify the feasibility of currently proposed methodology. Among the 160 qualitatively identified components, a total of 138 components were semi-quantified for these decoctions. Based on these results, we demonstrated that co-decoction of different herbs could result in concentration variations of components and this effect was more prominent when certain herbs were combined. Our results indicated that the present strategy would

  13. Immobilization of pectinesterase in genipin-crosslinked chitosan membrane for low methoxyl pectin production.

    PubMed

    Rangel-Rodríguez, Adriana Marisol; Conxita, Solans; Susana, Vílchez; Flores-Gallardo, Sergio Gabriel; Contreras-Esquivel, Juan Carlos; Licea-Jiménez, Liliana

    2014-12-01

    In this study, an environmentally friendly method for preparation of chitosan crosslinked membranes with different genipin concentrations (0, 125, 250, and 500 mg/L) was developed. Genipin-crosslinked chitosan membranes were used for the immobilization of fungal pectinesterase (PE). PE was efficiently immobilized in chitosan membranes and used for modification of high-methoxylated pectins into low-methoxylated pectins. The charge density (ζ-potential), infrared spectroscopy (FTIR), and ion-exchange chromatography (IEC) revealed the modification of pectin for immobilized PE in genipin-crosslinked chitosan membrane. The ζ-potential results indicated a decrease of -5.2 mV in the pectin control solution, whereas using the PE immobilized in chitosan and genipin-chitosan membranes, the obtained values were -30.45 mV and -36.38 mV, respectively. Genipin-crosslinked chitosan membrane jointly with the immobilized PE represents an eco-friendly support to prepare tailor-made low-methoxylated lime pectin.

  14. Improved protein kinase C affinity through final step diversification of a simplified salicylate-derived bryostatin analog scaffold.

    PubMed

    Wender, Paul A; Staveness, Daryl

    2014-10-01

    Bryostatin 1, in clinical trials or preclinical development for cancer, Alzheimer's disease, and a first-of-its-kind strategy for HIV/AIDS eradication, is neither readily available nor optimally suited for clinical use. In preceding work, we disclosed a new class of simplified bryostatin analogs designed for ease of access and tunable activity. Here we describe a final step diversification strategy that provides, in only 25 synthetic steps, simplified and tunable analogs with bryostatin-like PKC modulatory activities.

  15. Stable hydrogen and carbon isotope ratios of methoxyl groups during plant litter degradation.

    PubMed

    Anhäuser, Tobias; Greule, Markus; Zech, Michael; Kalbitz, Karsten; McRoberts, Colin; Keppler, Frank

    2015-01-01

    Stable hydrogen and carbon isotope ratios of methoxyl groups (δ(2)Hmethoxyl and δ(13)Cmethoxyl values, respectively) in plant material have been shown to possess characteristic signatures. These isotopic signatures can be used for a variety of applications such as constraining the geographical origin and authenticity of biomaterials. Recently, it has also been suggested that δ(2)Hmethoxyl values of sedimentary organic matter of geological archives might serve as a palaeoclimate/-hydrology proxy. However, deposited organic matter is subject to both biotic and abiotic degradation processes, and therefore an evaluation of their potential impact on the δ(2)Hmethoxyl and δ(13)Cmethoxyl values would allow more reliable interpretations of both isotopic signatures. Here, we investigated this potential influence by exposing foliar litter of five different tree species (Sycamore maple, Mountain ash, European beech, Norway spruce and Scots pine) to natural degradation. The foliar litter was sampled at nine intervals over a 27-month period, and the bulk methoxyl content as well as the δ(2)Hmethoxyl and δ(13)Cmethoxyl values were measured. At the end of the experiment, a loss of the bulk methoxyl in the range of ∼40-70% was measured. Linear regression analysis showed no dependence of δ(2)Hmethoxyl values with methoxyl content for four out of five foliar litter samples studied (R(2) in the range of 0.03 and 0.36, p > .05). On the contrary, the δ(13)Cmethoxyl values showed significant linear correlations for the great majority of the foliar litter samples (R(2) in the range of 0.51 and 0.73, p < .05). The litter species with the greatest methoxyl loss (Mountain ash, Scots pine and Norway spruce) showed the strongest (13)C enrichment, by up to ∼5‰. Since δ(2)Hmethoxyl shows no systematic overall change during the course of degradation, we propose that there is considerable potential for its use as a palaeoclimate proxy for a wide range of geological

  16. Diversity-oriented synthesis of medicinally important 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic) derivatives and higher analogs.

    PubMed

    Kotha, Sambasivarao; Deodhar, Deepak; Khedkar, Priti

    2014-12-01

    1,2,3,4-Tetrahydroisoquinoline-3-carboxylic acid (Tic) is a constrained analog of phenylalanine (Phe). The Tic unit has been identified as a core structural element present in several peptide-based drugs and forms an integral part of various biologically active compounds. This report covers the biological significance of the Tic core and provides a detailed account of various synthetic approaches available for the construction of Tic derivatives. Along with the traditional methods such as the Pictet-Spengler and Bischler-Nepieralski reactions, we cover various recent approaches such as enyne metathesis, [2 + 2 + 2] cycloaddition and the Diels-Alder reaction to generate Tic derivatives. In addition, syntheses of higher analogs of Tic are also discussed. PMID:25299735

  17. What climate information is recorded in stable isotope ratios of wood lignin methoxyl groups?

    NASA Astrophysics Data System (ADS)

    Greule, Markus; Keppler, Frank

    2010-05-01

    The stable isotope composition of the bioelements C, O, H and N in plant organic matter is known to be a very powerful for various environmental impacts. Particularly tree rings are suitable for this analysis because they exhibit a "climate archive" with a yearly or even biannual resolution. One of the most determined wood compounds is cellulose which amongst others is used to reconstruct the temperature due to measurement of stable hydrogen and oxygen isotopes. Therefore cellulose is converted into cellulose nitrate to eliminate the exchangeable hydroxyl hydrogen or equilibration methods are used. However, a general problem associated with the determination of the stable hydrogen values of marker compounds for the study of climate and environmental conditions is the isolation of the pure compound for analysis by isotope ratio mass spectrometry. Exploitation of components of wood as markers, in particular, has been restricted by the very labour intensive and time consuming preparation of samples (e.g. cellulose nitrate). An alternative way to record climate information from tree rings was recently proposed by Keppler et al. (2007) who measured the stable hydrogen values of methoxyl groups in wood. Lignin methoxyl groups are considered to be stable, i.e. the hydrogen atoms of the methoxyl moiety do not exchange with those of plant water during ongoing metabolic reactions in the plant. Thus the initial deuterium content of the methoxyl groups of lignin in woody tissue at formation is retained throughout the lifetime of the tree and in preserved tissue. The methoxyl content of lignin in wood is usually determined by the Zeisel method (Zeisel, 1885) - the reaction between methyl ethers and hydroiodic acid to form methyl iodide. Exploiting this reaction for the measurement of stable hydrogen values of lignin methoxyl groups ensures that during the entire analytical procedure the isotope signal is preserved since no isotopic exchange occurs between the methyl groups and

  18. Development of fluorinated methoxylated chalcones as selective monoamine oxidase-B inhibitors: Synthesis, biochemistry and molecular docking studies.

    PubMed

    Mathew, Bijo; Mathew, Githa Elizabeth; Uçar, Gülberk; Baysal, Ipek; Suresh, Jerad; Vilapurathu, Jobin Kunjumon; Prakasan, Aneesh; Suresh, Jeethu Kuruppath; Thomas, Anjana

    2015-10-01

    A series of methoxylated chalcones with fluoro and trifluoromethyl derivatives were synthesized and investigated for their ability to inhibit human monoamine oxidase A and B. The chemical structures of the compounds have been characterized by means of their (1)H NMR, (13)C NMR, Mass spectroscopic datas and elemental analysis. The results demonstrate that these compounds are reversible and selective MAO-B inhibitors with a competitive mode of inhibition. The most potent compound (2E)-1-(4-methoxyphenyl)-3-[4-(trifluoromethyl)phenyl] prop-2-en-1-one showed the best activity and higher selectivity towards hMAO-B with Ki and SI values of 0.22±0.01μM and 0.05 comparable to that standard drug, Selegiline Ki and SI values were found as 0.33±0.03μM and 0.04, respectively. Molecular docking studies were carried out to further explain the in vitro results of the new compounds, and to identify the hypothetical binding mode for the compounds inside the inhibitor binding cavity of hMAO-B.

  19. Antiangiogenic properties of substituted (Z)-(±)-2-(N-benzylindol-3-ylmethylene)quinuclidin-3-ol/one analogs and their derivatives.

    PubMed

    Venkateswaran, Amudhan; Reddy, Y Thirupathi; Sonar, Vijaykumar N; Muthusamy, Venkatraj; Crooks, Peter A; Freeman, Michael L; Sekhar, Konjeti R

    2010-12-15

    In the past half century research efforts have defined a critical role for angiogenesis in tumor growth and metastasis. We previously reported that inhibition of a novel target, ENOX1, by a (Z)-2-benzylindol-3-ylmethylene) quinuclidin-3-ol, suppressed tumor angiogenesis. The present study was undertaken in order to establish structure-activity relationships for quinuclidine analogs. The angiogenesis inhibiting activity of a series of substituted (Z)-(±)-2-(N-benzylindol-3-ylmethylene)quinuclidin-3-ols (1a-1k), (Z)-2-benzylindol-3-ylmethylene)quinuclidin-3-ones (2a-2h), (Z)-(±)-2-(1H/N-methyl-indol-3-ylmethylene)quinuclidin-3-ols (3a-3b), and substituted (Z)-(±)-2-(N-benzenesulfonylindol-3-yl-methylene)quinuclidin-3-ols and their derivatives (4a-4d) that incorporate a variety of substituents in both the indole and N-benzyl moieties was evaluated using Human Umbilical Vein Endothelial Cells (HUVECs) subjected to in vitro cell migration scratch assays, tubule formation in Matrigel, cell viability and proliferation assays. In total, 25 different analogs were evaluated. Based on in vitro cell migration scratch assays, eight analogs were identified as potent angiogenesis inhibitors at 10 μM, a concentration that was determined to be nontoxic by colony formation assay. In addition, this approach identified a potent antiangiogenic ENOX1 inhibitor, analog 4b.

  20. Lunar Analog

    NASA Technical Reports Server (NTRS)

    Cromwell, Ronita L.

    2009-01-01

    In this viewgraph presentation, a ground-based lunar analog is developed for the return of manned space flight to the Moon. The contents include: 1) Digital Astronaut; 2) Bed Design; 3) Lunar Analog Feasibility Study; 4) Preliminary Data; 5) Pre-pilot Study; 6) Selection of Stockings; 7) Lunar Analog Pilot Study; 8) Bed Design for Lunar Analog Pilot.

  1. Structure-activity relationship in the mutagenicity and cytotoxicity of putative metabolites and related analogs of benzene derived from the valence tautomers benzene oxide and oxepin

    SciTech Connect

    Stark, A.A.; Rastetter, W.H.

    1996-12-31

    A series of putative metabolites and related analogs of benzene, derived from the valence tautomers benzene oxide and oxepin, was tested for mutagenicity (reversions to histidine prototrophy and forward mutations to resistance to 8-azaguanine) and for cytotoxicity by the Ames Salmonella mutagenicity test. Benzene was not mutagenic in either assay. The benzene oxide-oxepin system and benzene dihydrodial induced point mutations but not frameshifts. 4,5-sym-Oxepin oxide, which is a putative metabolite of the oxepin valence tautomer; 3,6-diazo-cyclohexane-1,6-3,4-dioxide, a synthetic precursor of sym-oxepin oxide; and transoid-4,11-dioxatricyclo(5.1 0)undeca-1,6-diene, a stable bridgehead diene analog of sym-oxepin oxide, were toxic but not mutagenic in both assays. 4H-Pyran-4-=carboxaldehyde, a stable acid catalyzed rearrangement product of sym-oxepin oxide, was not mutagenic and much less cytotoxic than sym-oxepin oxide. Stable analogs of the valence tautomer benzene oxide, namely syn-indan-3a,7a-oxide and syn-2-hydroxyindan-3a,7a-oxide, were mutagenic and induced point mutations. All compounds were cytotoxic to Salmonella. Firstly, the apparent decay times of these chemicals, especially that of sym-oxepin oxide, were surprisingly longer than expected, as judged by quantitative plate diffusion assays. Secondly, it is concluded that if benzene oxide is further metabolized in its oxepin tautomeric form, toxic but not mutagenic products are formed. Thirdly, the relatively weak mutagenicity of benzene oxide may be mainly due to its instability and corresponding low probability to reach intracellular polynucleotide targets, whereas stable analogs of benzene oxide are relatively more potent mutagens. 48 refs., 4 figs., 3 tabs.

  2. Synthesis and characterization of an in situ forming hydrogel using tyramine conjugated high methoxyl gum tragacanth.

    PubMed

    Tavakol, Moslem; Vasheghani-Farahani, Ebrahim; Mohammadifar, Mohammad Amin; Soleimani, Masoud; Hashemi-Najafabadi, Sameereh

    2016-02-01

    In this study, an enzyme catalyzed in situ forming hydrogel based on tyramine conjugated high methoxyl content gum tragacanth (TA-HMGT) was prepared and characterized. TA-HMGT was synthesized via heterogeneous ammonolysis of methyl ester groups of HMGT. Then, the hydrogel was prepared via horseradish peroxidase catalyzed coupling reaction in the presence of hydrogen peroxide. Hydrogel properties, such as gelation time, swelling/degradation behavior and rheological properties could be adjusted by tuning the gelation parameters and extent of tyramine conjugation. This system was a soft elastic hydrogel with appropriate biocompatibility. The fast gelation of the hydrogel is desirable for clinical applications. Also, in vitro bovine serum albumin release from the synthesized hydrogel showed good release profile with limited burst release.

  3. Seasonal variations of hydroxylated and methoxylated brominated diphenyl ethers in blue mussels from the Baltic Sea.

    PubMed

    Löfstrand, Karin; Liu, Xitao; Lindqvist, Dennis; Jensen, Sören; Asplund, Lillemor

    2011-07-01

    Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) found at high levels in the Baltic biota are mainly natural products, but can also be formed through metabolism or abiotic oxidation of polybrominated diphenyl ethers (PBDEs). The formation of OH-PBDEs is of concern since there is growing evidence of phenolic toxicity. This study investigates seasonal variations in levels of OH-PBDEs and MeO-PBDEs, focusing on an exposed species, the blue mussel (Mytilus edulis), sampled in the Baltic Sea in May, June, August and October of 2008. Both the OH-PBDE and MeO-PBDE levels in the mussels showed seasonal variations from May to October, the highest concentration of each congener appearing in June. The seasonal variation was more marked for OH-PBDEs than in MeO-PBDEs, but all congeners showed the same trends, except 6-MeO-BDE47 and 2'-MeO-BDE68, which did not significantly decline in concentrations after June. Biotic or abiotic debromination is suggested as a possible reason for the rapid decrease in methoxylated penta- and hexa-BDE concentrations observed in blue mussels from June to August, while the tetraBDE concentrations were stable. In addition, 1,3,7/1,3,8-tribrominated dibenzo-p-dioxins showed the same seasonal variation. The seasonal variations indicates natural formation and are unlikely to be due to transformation of anthropogenic precursors. The levels of PBDEs were fairly constant over time and considerably lower than those of the OH-PBDEs and MeO-PBDEs. The timing of the peaks in concentrations suggests that filamentous macro-algae may be important sources of these compounds found in the blue mussels from this Baltic Sea location.

  4. Analog-to-digital conversion as a source of drifts in displacements derived from digital recordings of ground acceleration

    USGS Publications Warehouse

    Boore, D.M.

    2003-01-01

    Displacements obtained from double integration of digitally recorded ground accelerations often show drifts much larger than those expected for the true ground displacements. These drifts might be due to many things, including dynamic elastic ground tilt, inelastic ground deformation, hysteresis in the instruments, and cross feed due to misalignment of nominally orthogonal sensors. This article shows that even if those effects were not present, the analog-to-digital conversion (ADC) process can produce apparent "pulses" and offsets in the acceleration baseline if the ground motion is slowly varying compared with the quantization level of the digitization. Such slowly varying signals can be produced by constant offsets that do not coincide with a quantization level and by near- and intermediate-field terms in the wave field radiated from earthquakes. Double integration of these apparent pulses and offsets leads to drifts in the displacements similar to those found in processing real recordings. These effects decrease in importance as the resolution of the ADC process increases.

  5. Gene Expression Analysis of HCT116 Colon Tumor-derived Cells Treated with the Polyamine Analog PG-11047

    PubMed Central

    IGNATENKO, NATALIA A.; YERUSHALMI, HAGIT F.; PANDEY, RITU; KACHEL, KAREN L.; STRINGER, DAVID E.; MARTON, LAURENCE J.; GERNER, EUGENE W.

    2013-01-01

    Background The conformationally restricted polyamine analog PG-11047 has significant growth inhibitory activity against prostate and lung cancer cell lines and is currently under evaluation in several clinical trials, both alone and in combination with other drugs, for the treatment of relapsed or refractory cancer. The objective of this study was to identify the molecular signature of genes responsive to PG-11047 treatment and the biochemical effects of this drug in the HCT116 colon cancer cell line. Materials and Methods Gene expression analysis was performed using Affymetrix GeneChip human genome U133 Plus 2.0 arrays. Changes in protein expression were evaluated using 2D polyacrylamide gels followed by LCMS/MS. Results Treatment of cells with PG-11047 at concentrations ranging from 0.1 to 10 μM caused inhibition of cell growth. The activity of PG-11047 was found to correlate with its transcriptional effects on cell cycle control, focal adhesion, adherent and gap junction genes, MAPK-, Wnt- and, TGF-β signaling pathways, transport and DNA/RNA transcription factor genes. PG-11047 caused depletion of polyamine pools. Proteomics analysis showed that PG-11047 restricts the modification of eukaryotic translation initiation factor 5A (eIF5A), resulting in suppression of general protein synthesis in PG-11047-treated cells. Conclusion These data show that PG-11047 has a broad spectrum of anticancer activity in colon cancer cells. PMID:19487545

  6. Methoxylated polybrominated diphenyl ethers (MeO-PBDEs) are major contributors to the persistent organobromine load in sub-Arctic and Arctic marine mammals, 1986-2009.

    PubMed

    Rotander, Anna; van Bavel, Bert; Rigét, Frank; Auðunsson, Guðjón Atli; Polder, Anuschka; Gabrielsen, Geir Wing; Víkingsson, Gísli; Mikkelsen, Bjarni; Dam, Maria

    2012-02-01

    A selection of MeO-BDE and BDE congeners were analyzed in pooled blubber samples of pilot whale (Globicephala melas), ringed seal (Phoca hispida), minke whale (Balaenoptera acutorostrata), fin whale (Balaenoptera physalus), harbor porpoise (Phocoena phocoena), hooded seal (Cystophora cristata), and Atlantic white-sided dolphin (Lagenorhynchus acutus), covering a time period of more than 20 years (1986-2009). The analytes were extracted and cleaned-up using open column extraction and multi-layer silica gel column chromatography. The analysis was performed using both low resolution and high resolution GC-MS. MeO-PBDE concentrations relative to total PBDE concentrations varied greatly between sampling periods and species. The highest MeO-PBDE levels were found in the toothed whale species pilot whale and white-sided dolphin, often exceeding the concentration of the most abundant PBDE, BDE-47. The lowest MeO-PBDE levels were found in fin whales and ringed seals. The main MeO-BDE congeners were 6-MeO-BDE47 and 2'-MeO-BDE68. A weak correlation only between BDE47 and its methoxylated analog 6-MeO-BDE47 was found and is indicative of a natural source for MeO-PBDEs. PMID:22225820

  7. Trans Fatty Acid Derived Phospholipids Show Increased Membrane Cholesterol and Reduced Receptor Activation as Compared to Their Cis Analogs

    PubMed Central

    Niu, Shui-Lin; Mitchell, Drake C.; Litman, Burton J.

    2005-01-01

    The consumption of trans fatty acid (TFA) is linked to the elevation of LDL cholesterol and is considered to be a major health risk factor for coronary heart disease. Despite several decades of extensive research on this subject, the underlying mechanism of how TFA modulates serum cholesterol levels remains elusive. In this study, we examined the molecular interaction of TFA-derived phospholipid with cholesterol and the membrane receptor rhodopsin in model membranes. Rhodopsin is a prototypical member of the G-protein coupled receptor family. It has a well-characterized structure and function and serves as a model membrane receptor in this study. Phospholipid–cholesterol affinity was quantified by measuring cholesterol partition coefficients. Phospholipid–receptor interactions were probed by measuring the level of rhodopsin activation. Our study shows that phospholipid derived from TFA had a higher membrane cholesterol affinity than their cis analogues. TFA phospholipid membranes also exhibited a higher acyl chain packing order, which was indicated by the lower acyl chain packing free volume as determined by DPH fluorescence and the higher transition temperature for rhodopsin thermal denaturation. The level of rhodopsin activation was diminished in TFA phospholipids. Since membrane cholesterol level and membrane receptors are involved in the regulation of cholesterol homeostasis, the combination of higher cholesterol content and reduced receptor activation associated with the presence of TFA–phospholipid could be factors contributing to the elevation of LDL cholesterol. PMID:15766276

  8. 1H NMR and Rheological Studies of the Calcium Induced Gelation Process in Aqueous Low Methoxyl Pectin Solutions

    NASA Astrophysics Data System (ADS)

    Dobies, M.; Kuśmia, S.; Jurga, S.

    2006-07-01

    The 1H NMR relaxometry in combination with water proton spin-spin relaxation time measurements and rheometry have been applied to study the ionic gelation of 1% w/w aqueous low methoxyl pectin solution induced by divalent Ca2+ cations from a calcium chloride solution. The model-free approach to the analysis of 1H NMR relaxometry data has been used to separate the information on the static (β) and dynamic (<τ_c>) behaviour of the systems tested. The 1H NMR results confirm that the average mobility of both water and the pectin molecules is largely dependent on the concentration of the cross-linking agent. The character of this dependency (β,<τc> and T2 vs. CaCl2 concentration) is consistent with the two-stage gelation process of low methoxyl pectin, in which the formation of strongly linked dimer associations (in the range of 0-2.5 mM CaCl2) is followed by the appearance of weak inter-dimer aggregations (for CaCl2≥ 3.5 mM). The presence of the weak gel structure for the sample with 3.5 mM CaCl2 has been confirmed by rheological measurements. Apart from that, the T1 and T2 relaxation times have been found to be highly sensitive to the syneresis phenomenon, which can be useful to monitor the low methoxyl pectin gel network stability.

  9. Dietary exposure to phenolic and methoxylated organohalogen contaminants in relation to their concentrations in breast milk and serum in Japan.

    PubMed

    Fujii, Yukiko; Nishimura, Eri; Kato, Yoshihisa; Harada, Kouji H; Koizumi, Akio; Haraguchi, Koichi

    2014-02-01

    This study investigated human exposure to neutral, phenolic, and methoxylated organohalogen contaminants (OHCs) in a duplicate diet study to evaluate their concentrations in breast milk and serum of Okinawan people from Japan during 2004-2009. Dietary intakes of phenolic OHCs were predominantly 2,4,6-tribromophenol (TriBP), followed by tetrabromobisphenol A (TBBPA), and 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE47). After exposure, TriBP and TBBPA were transferred to breast milk, whereas 6-OH-BDE47 was selectively retained in serum. Despite a lower dietary exposure to pentachlorophenol and 4-hydroxy-CB187, both were retained in serum. For the methoxylated OHCs, 2,4,6-tribromoanisole (TriBA) and 6-methoxy-BDE47 were the predominant dietary contaminants, of which TriBA was present in both breast milk and serum, whereas 6-methoxy-BDE47 was selectively transferred to breast milk. These findings suggest that dietary exposure to phenolic and methoxylated OHCs may result in differential partitioning between breast milk and serum with different pharmacokinetic or exposure routes. PMID:24263137

  10. Comparison of the growth promoting activities and toxicities of various auxin analogs on cells derived from wild type and a nonrooting mutant of tobacco

    SciTech Connect

    Caboche, M.; Muller, J.F. ); Chanut, F. ); Aranda, G.; Cirakoglu, S. )

    1987-01-01

    A naphthaleneacetic acid tolerant mutant isolated from a mutagenized culture of tobacco mesophyll protoplasts and impaired in root morphogenesis has been previously characterized by genetic analysis. To understand the biochemical basis for naphthaleneacetic acid resistance, cells derived from this mutant and from wild-type tobacco were compared for their ability to respond to various growth regulators. The growth promoting abilities and cytotoxicities of auxin analogs were different for mutant and wild-type cells. These different activities were not correlated with increased rate of conjugation or breakdown of the auxins by mutant cells. These observations, as well as previous studies on the interaction of the mutant with Agrobacterium, suggest that mutant resistance to auxins is not a result of a specific modification of the process by which auxins induce cell killing, but to a more general alteration of the cellular response to auxin. A screening of auxin-related molecules which induce cell death in wild-type cells but not mutant cells without promoting growth in either was performed. p-Bromophenyleacetic acid was found to display these characteristics.

  11. Analog earthquakes

    SciTech Connect

    Hofmann, R.B.

    1995-09-01

    Analogs are used to understand complex or poorly understood phenomena for which little data may be available at the actual repository site. Earthquakes are complex phenomena, and they can have a large number of effects on the natural system, as well as on engineered structures. Instrumental data close to the source of large earthquakes are rarely obtained. The rare events for which measurements are available may be used, with modfications, as analogs for potential large earthquakes at sites where no earthquake data are available. In the following, several examples of nuclear reactor and liquified natural gas facility siting are discussed. A potential use of analog earthquakes is proposed for a high-level nuclear waste (HLW) repository.

  12. Producing and Recognizing Analogical Relations

    ERIC Educational Resources Information Center

    Lipkens, Regina; Hayes, Steven C.

    2009-01-01

    Analogical reasoning is an important component of intelligent behavior, and a key test of any approach to human language and cognition. Only a limited amount of empirical work has been conducted from a behavior analytic point of view, most of that within Relational Frame Theory (RFT), which views analogy as a matter of deriving relations among…

  13. PBDEs, hydroxylated PBDEs and methoxylated PBDEs in bivalves from Beijing markets.

    PubMed

    Liu, Xitao; Jiao, Ying; Lin, Chunye; Sun, Ke; Zhao, Ye

    2014-09-01

    The structural analogues of polybrominated diphenyl ethers (PBDEs), hydroxylated PBDEs (OH-PBDEs) and methoxylated PBDEs (MeO-PBDEs) have been attracting increasing concern in recent years. Five bivalve species (blue mussel, short-necked clam, surf clam, ark shell and razor clam) were collected from Beijing markets, and the concentrations of seven PBDEs, four OH-PBDEs and fourteen MeO-PBDEs in the bivalves were measured. The seasonal variations of these three types of polybrominated compound in blue mussels were also monitored. The results indicate that the levels of ΣPBDEs in this study were comparable to those in short-necked clams from Liaodong Bay, China, with BDE47 as the dominant congener. For the ortho-MeO-PBDEs, 6-MeO-BDE47 was found at higher concentrations than the others, while for the meta- and para-MeO-PBDEs, 4'-MeO-BDE17 was found at higher concentrations. 6-OH-BDE-47 was the most abundant congener among the 4 measured OH-PBDEs, followed by 6-OH-BDE-137 and 6-OH-BDE-85. The levels of OH-PBDEs and MeO-PBDEs in bivalves from Beijing markets were much lower than the corresponding compounds in blue mussels from the Baltic Sea. In the blue mussels collected in April, June and September of 2012, apparent seasonal variations were observed for these three types of polybrominated compounds, but the acidic components displayed different trends from the neutral components, with PBDEs and MeO-PBDEs showing the highest concentrations in June, while OH-PBDEs had the lowest concentrations in June. This difference in seasonal variations between the neutral components and the acidic components may be explained by their different sources and transformation/elimination mechanisms.

  14. Anomeric selectivity and influenza A virus inhibition study on methoxylated analogues of Pentagalloylglucose.

    PubMed

    Qurat-ul-ain, Shaikh; Wang, Wei; Yang, Meiting; Du, Na; Wan, Shengbiao; Zhang, Lijuan; Jiang, Tao

    2015-01-30

    Anomeric selectivity in galloylation of D-glucose and D-mannose with carboxylic acid was explored under steglich conditions. Base catalyst 4-dimethylaminopyridine favored the formation of alpha-anomers, while adding an acid and carbodiimide favored the formation of beta-anomers. Steric hindrance between α,β-unsaturated acid and C-2 OH stereochemistry (adjacent carbon to anomeric) influenced anomeric selectivity for both D-glucose and D-mannose. The influenza A virus inhibition activities of the synthesized compounds were evaluated in Madin-Darby canine kidney cell line using the cytopathic effect inhibition assay. All the synthetic methoxylated analogues showed more considerable activity against influenza A virus than their corresponding acids, which indicated the sugar core as key functionality for anti-viral activity. The activities of trimethoxy-cinnamic acid Pentagalloylglucose analogues, 3α, 3β, 4α, and 4β (IC50, 109.1 μM, 134.4 μM, 119.5 μM, 111.1 μM, respectively) were better than those of trimethoxy-benzoic acid Pentagalloylglucose analogues, 1-αβ and 2α, 2β (IC50, 209.8 μM, 132.9 μM, 161.2 μM, respectively), which suggested that the double bond in cinnamic acid Pentagalloylglucose analogues makes the major contribution for influenza A virus inhibitory activity. Notably, several anomeric mixtures showed better activities than pure alpha or beta anomer and were almost two times more effective than Ribavirin, a clinically used anti-viral drug. PMID:25498015

  15. Theoretical and Analog Studies of the Effects of Nonlinear Stability Derivatives on the Longitudinal Motions of an Aircraft in Response to Step Control Deflections and to the Influence of Proportional Automatic Control

    NASA Technical Reports Server (NTRS)

    Curfman, Howard J , Jr

    1955-01-01

    Through theoretical and analog results the effects of two nonlinear stability derivatives on the longitudinal motions of an aircraft have been investigated. Nonlinear functions of pitching-moment and lift coefficients with angle of attack were considered. Analog results of aircraft motions in response to step elevator deflections and to the action of the proportional control systems are presented. The occurrence of continuous hunting oscillations was predicted and demonstrated for the attitude stabilization system with proportional control for certain nonlinear pitching-moment variations and autopilot adjustments.

  16. Triptycene analogs

    NASA Technical Reports Server (NTRS)

    Hua, Duy (Inventor); Perchellet, Jean-Pierre (Inventor)

    2004-01-01

    This invention provides analogs of triptycene which are useful as anticancer drugs, as well as for other uses. The potency of these compounds is in a similar magnitude as daunomycin, a currently used anticancer drug. Each compound of the invention produces one or more desired effects (blocking nucleoside transport, inhibiting nucleic acid or protein syntheses, decreasing the proliferation and viability of cancer cells, inducing DNA fragmentation or retaining their effectiveness against multidrug-resistant tumor cells).

  17. 5-Methoxyl Aesculetin Abrogates Lipopolysaccharide-Induced Inflammation by Suppressing MAPK and AP-1 Pathways in RAW 264.7 Cells

    PubMed Central

    Wu, Lei; Li, Xueqin; Wu, Haifeng; Long, Wei; Jiang, Xiaojian; Shen, Ting; Qiang, Qian; Si, Chuanling; Wang, Xinfeng; Jiang, Yunyao; Hu, Weicheng

    2016-01-01

    For the first time, a pale amorphous coumarin derivative, 5-methoxyl aesculetin (MOA), was isolated from the dried bark of Fraxinus rhynchophylla Hance (Oleaceae). MOA modulates cytokine expression in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages, but the precise mechanisms are still not fully understood. We determined the effects of MOA on the production of inflammatory mediators and pro-inflammatory cytokines in the LPS-induced inflammatory responses of RAW 264.7 macrophages. MOA significantly inhibited the LPS-induced production of nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), interleukin-6, and interleukin-1β. It also effectively attenuated inducible nitric oxide (NO) synthase, cyclooxygenase-2, and TNF-α mRNA expression and significantly decreased the levels of intracellular reactive oxygen species. It inhibited phosphorylation of the extracellular signal-regulated kinase (ERK1/2), thus blocking nuclear translocation of activation protein (AP)-1. In a molecular docking study, MOA was shown to target the binding site of ERK via the formation of three hydrogen bonds with two residues of the kinase, which is sufficient for the inhibition of ERK. These results suggest that the anti-inflammatory effects of MOA in RAW 264.7 macrophages derive from its ability to block both the activation of mitogen-activated protein kinases (MAPKs) and one of their downstream transcription factors, activator protein-1 (AP-1). Our observations support the need for further research into MOA as a promising therapeutic agent in inflammatory diseases. PMID:26938526

  18. Constrained analogs of CB-1 antagonists: 1,5,6,7-Tetrahydro-4H-pyrrolo[3,2-c]pyridine-4-one derivatives.

    PubMed

    Smith, Roger A; Fathi, Zahra; Brown, Su-Ellen; Choi, Soongyu; Fan, Jianmei; Jenkins, Susan; Kluender, Harold C E; Konkar, Anish; Lavoie, Rico; Mays, Ronald; Natoli, Jennifer; O'Connor, Stephen J; Ortiz, Astrid A; Podlogar, Brent; Taing, Christy; Tomlinson, Susan; Tritto, Theresa; Zhang, Zhonghua

    2007-02-01

    A series of pyrrolopyridinones was designed and synthesized as constrained analogs of the pyrazole CB-1 antagonist rimonabant. Certain examples exhibited very potent hCB-1 receptor binding affinity and functional antagonism with Ki and Kb values below 10 nM, and with high selectivity for CB-1 over CB-2 (>100-fold). A representative analog was established to cause significant appetite suppression and reduction in body weight gain in industry-standard rat models used to develop new therapeutics for obesity. PMID:17107792

  19. Analogy, explanation, and proof

    PubMed Central

    Hummel, John E.; Licato, John; Bringsjord, Selmer

    2014-01-01

    People are habitual explanation generators. At its most mundane, our propensity to explain allows us to infer that we should not drink milk that smells sour; at the other extreme, it allows us to establish facts (e.g., theorems in mathematical logic) whose truth was not even known prior to the existence of the explanation (proof). What do the cognitive operations underlying the inference that the milk is sour have in common with the proof that, say, the square root of two is irrational? Our ability to generate explanations bears striking similarities to our ability to make analogies. Both reflect a capacity to generate inferences and generalizations that go beyond the featural similarities between a novel problem and familiar problems in terms of which the novel problem may be understood. However, a notable difference between analogy-making and explanation-generation is that the former is a process in which a single source situation is used to reason about a single target, whereas the latter often requires the reasoner to integrate multiple sources of knowledge. This seemingly small difference poses a challenge to the task of marshaling our understanding of analogical reasoning to understanding explanation. We describe a model of explanation, derived from a model of analogy, adapted to permit systematic violations of this one-to-one mapping constraint. Simulation results demonstrate that the resulting model can generate explanations for novel explananda and that, like the explanations generated by human reasoners, these explanations vary in their coherence. PMID:25414655

  20. Climate signal in d13C of wood lignin methoxyl groups from high-elevation alpine larch trees

    NASA Astrophysics Data System (ADS)

    Reichelmann, Dana; Greule, Markus; Treydte, Kerstin; Keppler, Frank; Esper, Jan

    2015-04-01

    Tree-rings of high alpine larch trees (Larix decidua) were investigated by a recently established method that measures d13C values of the wood lignin methoxyl groups (Greule et al. 2009). The resulting d13C time series were tested for their potential as a climate proxy. For this 37 larch trees were sampled at the tree line near Simplon Village (Southern Switzerland). They were analysed for their tree-ring width (TRW) and from five individuals d13C of the wood lignin methoxyl groups (d13Cmethoxyl) were measured at annual resolution from 1971-2009 and at pentadal resolution from 1747-2009. The d13Cmethoxyl chronologies were corrected for the anthropogenic change in atmospheric CO2 concentration and its decreasing d13C value. Further, the physiological response of the trees to these atmospheric changes was corrected using the flexible correction factor approach of Treydte et al. (2009), which minimise the residuals with the target climate data. This approach results in the highest so far reported correction factors of 0.032 - 0.036‰/ppmv CO2, which are explained by a low water-use efficiency of deciduous larch. The climate response of the new d13Cmethoxyl proxy shows a significant correlation of 0.75 for the annually and 0.87 for the pentadally resolved data with June to August temperatures. TRW shows also significant correlations with June to August temperatures, but they are lower than the correlations observed for the d13Cmethoxyl chronologies. These results indicate the potential of d13Cmethoxyl chronologies as a summer temperature proxy from high-elevation alpine trees with an even stronger signal than reported from earlier published tree-ring width and maximum latewood density temperature reconstructions. References: Greule, M., Mosandl, A., Hamilton, J.T.G., Keppler, F., 2009. A simple rapid method to precisely determine 13C/12C ratios of plant methoxyl groups. Rapid Communications in Mass Spectrometry, 23(11): 1710-1714. Treydte, K.S., Frank, D.C., Saurer, M

  1. Neural Analog Information Processing

    NASA Astrophysics Data System (ADS)

    Hecht-Nielsen, Robert

    1982-07-01

    Neural Analog Information Processing (NAIP) is an effort to develop general purpose pattern classification architectures based upon biological information processing principles. This paper gives an overview of NAIP and its relationship to the previous work in neural modeling from which its fundamental principles are derived. It also presents a theorem concerning the stability of response of a slab (a two dimensional array of identical simple processing units) to time-invariant (spatial) patterns. An experiment (via computer emulation) demonstrating classification of a spatial pattern by a simple, but complete NAIP architecture is described. A concept for hardware implementation of NAIP architectures is briefly discussed.

  2. Enhanced killing of breast cancer cells by a d-amino acid analog of the winter flounder-derived pleurocidin NRC-03.

    PubMed

    Hilchie, Ashley L; Haney, Evan F; Pinto, Devanand M; Hancock, Robert E W; Hoskin, David W

    2015-12-01

    Cationic antimicrobial peptides (CAPs) defend against pathogens and, in some cases, exhibit potent anticancer activities. We previously reported that the pleurocidin NRC-03 causes lysis of breast cancer and multiple myeloma cells. NRC-03 also reduces the EC50 of other cytotoxic compounds and prevents tumor growth in vivo. However, the therapeutic utility of NRC-03 may be limited by its susceptibility to degradation by proteases. The goal of this study was to characterize the anticancer activities of a d-amino acid analog of NRC-03 ([D]-NRC-03) that was predicted to be resistant to proteolytic degradation. Unlike NRC-03, [D]-NRC-03 was not degraded by human serum or trypsin and, in comparison to NRC-03, showed increased killing of breast cancer cells, including multidrug-resistant cells; however, [D]-NRC-03 was somewhat more cytotoxic than NRC-03 for several types of normal cells. Importantly, [D]-NRC-03 was more effective than NRC-03 in vivo since 4-fold less peptide was required for an equivalent inhibitory effect on the growth of breast cancer cell xenografts in immune-deficient mice. These findings demonstrate that a d-amino acid analog of NRC-03 overcomes a major limitation to the therapeutic use of NRC-03, namely peptide stability. Further modification of [D]-NRC-03 is required to improve its selectivity for cancer cells.

  3. Monitoring structural transformations in crystals. Part 4. Monitoring structural changes in crystals of pyridine analogs of chalcone during /[2+2]-photodimerization and possibilities of the reaction in hydroxy derivatives

    NASA Astrophysics Data System (ADS)

    Turowska-Tyrk, Ilona; Grześniak, Karolina; Trzop, Elżbieta; Zych, Tomasz

    2003-09-01

    We studied the [2+2]-photodimerization in crystals of pyridine analogs and hydroxy derivatives of chalcone using the X-ray structure analysis. The mutual orientation of adjacent molecules in the crystals was analyzed in a quantitative way and the results were compared with data for known photoactive crystals undergoing the [2+2]-photodimerization. In the case of one pyridine analog, we processed the single-crystal-to-single-crystal photodimerization and determined the structure for the mixed crystal containing both the substrate and the product. We also explained a role of hydrogen bonds in the [2+2]-photodimerization in the case of the hydroxy derivatives of chalcone. C 5H 4N-CO-CHCH-C 6H 5: a=6.0885(7) Å, b=13.1022(14) Å, c=13.7197(17) Å, β=91.318(10)°, monoclinic, P2 1/n, Z=4 . The irradiated crystal of the above analog: a=6.1502(7) Å, b=12.9740(13) Å, c=13.7964(15) Å, β=91.870(10)°, monoclinic, P2 1/n, Z=4 . C 6H 5-CO-CHCH-C 5H 4N: a=23.907(6) Å, b=4.6709(10) Å, c=21.199(6) Å, β=110.01(3)°, monoclinic, C2/c, Z=8 . C 6H 5-CO-CHCH-C 6H 4( o-OH): a=13.295(6) Å, b=5.659(2) Å, c=16.144(8) Å, β=109.73(5)°, monoclinic, P2 1/n, Z=4 . C 6H 5-CO-CHCH-C 6H 4( p-OH): a=5.3446(7) Å, b=12.9304(18) Å, c=17.134(2) Å, orthorhombic, P2 12 12 1, Z=4 .

  4. Vitamin D analog EB1089 could repair the defective bone marrow-derived mesenchymal stromal cells in patients with systemic lupus erythematosus.

    PubMed

    Xu, Jing-Jing; Sun, Yan-Bin; Zhang, Xiao-Li; Wang, Xiao-Fei

    2015-01-01

    Systemic lupus erythematosus (SLE) involves multiple factors, which result in the breakdown of self-tolerance and development of autoimmunity with organ damage. Bone marrow mesenchymal stem cells (BMMSCs) from the patients with SLE showed an impaired proliferative capacity compared with that from normal controls. In this study, we isolated BMMSCs from the patients with SLE and found that Vitamin D analog EB1089 could induce BMMSCs proliferation and mineralization deposition. Furthermore, we found that the expression of p-Smad 1/5/8 was promoted in BMMSCs with EB1089 treatment. In conclusion, our results support the notion that EB1089 promoted proliferation and osteogenic differentiation of BMMSCs by Smad 1/5/8 signaling pathway.

  5. Induction of apoptosis and inhibition of prostate and breast cancer growth by BGP-15, a new calcipotriene-derived vitamin D3 analog.

    PubMed

    Berkovich, Liron; Ben-Shabat, Shimon; Sintov, Amnon C

    2010-07-01

    The role of vitamin D3 in cancer prevention and its potential as an anticancer therapeutic agent have been researched and are well established. However, the clinical use of the natural vitamin D3 metabolite, 1alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3 or calcitriol] is limited by a possible cause of hypercalcemia and hypercalciuria. A new 24-chloro calcipotriene-based vitamin D3 analog (BGP-15) was synthesized and examined for antiproliferative activity in the androgen-dependent cell lines of prostate cancer (LNCaP) and breast cancer (MCF-7). The new analog led to significant decrease in cell viability in cultured LNCaP and MCF-7 cell lines compared with calcipotriene and 1,25(OH)2D3. We observed elevated vitamin D receptor protein levels in both LNCaP and MCF-7 cells, which were treated with 5 micromol/l of 1,25(OH)2D3, calcipotriene or BGP-15 for 20 h, indicating vitamin D receptor-binding ability. Treatments of LNCaP and MCF-7 cells with 5 micromol/l BGP-15 and calcipotriene for 20 h generated procaspase-3 cleavage and therefore, apoptosis. Interestingly, BGP-15, and to a lesser extent calcipotriene, but not 1,25(OH)2D3, activated caspase-3 in MCF-7 cells, a cell line that normally lacks this specific caspase (and procaspase). It is presumed that management of MCF-7 with BGP-15 modulates procaspase-3 expression and cleavage, and a subsequent activation of caspase-3. Similar treatments of LNCaP cells induced procaspase-9 cleavage and therefore caspase-9 activation, whereas similar treatments of MCF-7 cells failed to induce caspase-9 activation. Cytochrome c release was, however, detected in both cell lines, LNCaP and MCF-7. In-vivo results suggested that BGP-15 (similar to its parent drug) did not cause calcium-related toxic side effects after chronic treatment.

  6. Graphene-encapsulated silica as matrix solid-phase dispersion extraction sorbents for the analysis of poly-methoxylated flavonoids in the leaves of Murraya panaculata (L.) Jack.

    PubMed

    Sun, Ting; Li, Xuwen; Yang, Jie; Li, Lanjie; Jin, Yongri; Shi, Xiaolei

    2015-06-01

    In this study, graphene-encapsulated silica was synthesized by a hydrothermal reduction strategy. The presence of silica in graphene was identified by Fourier-transform infrared spectrometry, X-ray diffraction and scanning electron microscopy. The graphene-encapsulated silica subsequently was used as adsorbent for matrix solid-phase dispersion extraction of poly-methoxylated flavonoids from the dried leaves of Murraya panaculata (L.) Jack. Compared with the other adsorbents (graphene, silica gel, C18 silica, neutral alumina, diatomaceous earth) and without any adsorbents, better results were obtained. Then a method for analysis of poly-methoxylated flavonoids was established by coupling matrix solid-phase dispersion extraction with ultra high performance liquid chromatography and UV detection. Compared with reflux extraction and ultrasonic extraction, the proposed method is quicker, more efficient and more environmental protection. Less than 10 min is needed from extraction to detection. PMID:25847864

  7. 1H and 13C NMR assignments of new methoxylated furanoflavonoids from Lonchocarpus araripensis.

    PubMed

    Lima, Almi F; Mileo, Paulo Graziane M; Andrade-Neto, Manoel; Braz-Filho, Raimundo; Silveira, Edilberto R; Pessoa, Otília Deusdênia L

    2009-02-01

    Two new polymethoxylated flavonoids, 2',5',6'-trimethoxy-[2'',3'' : 3',4']furano dihydrochalcone and 2,4',4,5-tetramethoxy-[2'',3'' : 6,7]-furanodihydroaurone, were isolated from the root barks of Lonchocarpus araripensis, along with the known compounds 3,4,5,6-tetramethoxy-[2'',3'' : 7,8]-furanoflavan, 3,6-dimethoxy-1'',1''-dimethylcromene-[2'',3'' : 7,8]-flavone, 3',4'-methylenodioxy-5,6-dimethoxy-[2'',3'' : 7,8]-furanoflavone, 3,5,6-trimethoxy-[2'',3'' : 7,8]-furanoflavanone, 3,5,6-trimethoxy-[2'',3'' : 7,8]-furanoflavone, and 6alpha-hydroxy-medicarpin. The complete (1)H and (13)C NMR assignments of the new furan flavonoids were performed using 1D and 2D pulse sequences, including COSY, HSQC, and HMBC experiments, and comparison with spectral data for analog compounds from the literature, particularly for the new furanodihydroaurone because of several inconsistencies on the carbonyl chemical shifts from the literature. PMID:18932264

  8. The effect of 17-methoxyl-7-hydroxy-benzene-furanchalcone isolated from Millettia pulchra on myocardial ischemia in vitro and in vivo.

    PubMed

    Jian, Jie; Qing, Feizhang; Zhang, Shijun; Huang, Jianchun; Huang, Renbin

    2012-08-01

    The effect of 17-methoxyl-7-hydroxy-benzene-furanchalcone isolated from the roots of Millettia pulchra (Benth.) Kurz var. Laxior (Dunn) Z. Wei on rat myocardial ischemia has been investigated. An in vitro cardiocyte apoptosis model and an in vivo myocardial ischemia model were used to elucidate the mechanism of 17-methoxyl-7-hydroxy-benzene-furanchalcone. In contrast to hydrogen peroxide (H2O2, 100 µmol/L), 17-methoxyl-7-hydroxy-benzene-furanchalcone in vitro (255 and 510 µmol/L) increased the quantity of total superoxide dismutase and the protein expression of B cell lymphoma/leukemia-2, while it inhibited cardiocyte apoptosis, the release of malondialdehyde and tumor necrosis factor α, and protein expression of nuclear factor κ Bp65 and Bcl-2-associated X protein. Furthermore, pretreatment with MHBFC in vivo (10 and 20 mg/kg) decreased heart rate, systolic pressure, diastolic pressure, average pressure, left ventricular systolic pressure, the largest upstroke velocity of the left ventricular pressure (+ dp/dtmax), total antioxidative capability, myoglobin isoenzyme of creatine kinase, and inducible nitric oxide synthase, while it increased endothelial nitric oxide synthase, ATPases, left ventricular diastolic pressure, left ventricular end-diastolic pressure, the largest descendent velocity of the left ventricular pressure (-dp/dtmax) and the interval from the beginning of left ventricular contraction to +dp/dtmax (t - dp/dtmax), all in a dose-dependent manner. Our present results suggest that 17-methoxyl-7-hydroxy-benzene-furanchalcone is an attractive antimyocardial ischemia agent mostly because of its negative heart rate and negative inotropic effects, the reduction in myocardial oxidative damage, and the modulating expression of genes associated with apoptosis, which improves diastolic function. PMID:22700048

  9. Analog current mode analog/digital converter

    NASA Technical Reports Server (NTRS)

    Hadidi, Khayrollah (Inventor)

    1996-01-01

    An improved subranging or comparator circuit is provided for an analog-to-digital converter. As a subranging circuit, the circuit produces a residual signal representing the difference between an analog input signal and an analog of a digital representation. This is achieved by subdividing the digital representation into two or more parts and subtracting from the analog input signal analogs of each of the individual digital portions. In another aspect of the present invention, the subranging circuit comprises two sets of differential input pairs in which the transconductance of one differential input pair is scaled relative to the transconductance of the other differential input pair. As a consequence, the same resistor string may be used for two different digital-to-analog converters of the subranging circuit.

  10. Microtubule-stabilizing properties of the avocado-derived toxins (+)-(R)-persin and (+)-(R)-tetrahydropersin in cancer cells and activity of related synthetic analogs.

    PubMed

    Field, Jessica J; Kanakkanthara, Arun; Brooke, Darby G; Sinha, Saptarshi; Pillai, Sushila D; Denny, William A; Butt, Alison J; Miller, John H

    2016-06-01

    The avocado toxin (+)-R-persin (persin) is active at low micromolar concentrations against breast cancer cells and synergizes with the estrogen receptor modulator 4-hydroxytamoxifen. Previous studies in the estrogen receptor-positive breast cancer cell line MCF-7 indicate that persin acts as a microtubule-stabilizing agent. In the present study, we further characterize the properties of persin and several new synthetic analogues in human ovarian cancer cells. Persin and tetrahydropersin cause G2M cell cycle arrest and increase intracellular microtubule polymerization. One analog (4-nitrophenyl)-deshydroxypersin prevents cell proliferation and blocks cells in G1 of the cell cycle rather than G2M, suggesting an additional mode of action of these compounds independent of microtubules. Persin can synergize with other microtubule-stabilizing agents, and is active against cancer cells that overexpress the P-glycoprotein drug efflux pump. Evidence from Flutax-1 competition experiments suggests that while the persin binding site on β-tubulin overlaps the classical taxoid site where paclitaxel and epothilone bind, persin retains activity in cell lines with single amino acid mutations that affect these other taxoid site ligands. This implies the existence of a unique binding location for persin at the taxoid site. PMID:26968704

  11. Transcriptional response of Candida albicans biofilms following exposure to 2-amino-nonyl-6-methoxyl-tetralin muriate

    PubMed Central

    Liang, Rong-mei; Cao, Yong-bing; Zhou, You-jun; Xu, Yi; Gao, Ping-hui; Dai, Bao-di; Yang, Feng; Tang, Hui; Jiang, Yuan-ying

    2010-01-01

    Aim: To identify changes in the gene expression profile of Candida albicans (C albicans) biofilms following exposed to 2-amino-nonyl-6-methoxyl-tetralin muriate(10b) and clarify the mechanism of 10b against C albicans biofilms. Methods: Anti-biofilm activity of 10b was assessed by tetrazolium (XTT) reduction assay and the action mechanism against biofilms was investigated by cDNA microarray analysis and real-time RT-PCR assay. Results: Ten differentially expressed genes were directly linked to biofilm formation and filamentous or hyphal growth (eg, NRG1, ECE1 and CSA1). Decreased gene expression was involved in glycolysis (eg, HXK2 and PFK1) and antioxidant defense (eg, SOD5), while increased gene expression was associated with enzymes that specifically hydrolyzed β-1,3 glucan (XOG1), and with lipid, fatty acid and sterol metabolism (eg, SLD1, ERG6 and ERG2). Functional analysis indicated that addition of anti-oxidant ascorbic acid reduced inhibitory efficiency of 10b on mature biofilm. Conclusion: Inhibition of 10b on biofilm formation possibly depends on impairing the ability of C albicans to change its morphology via altering the expression of biofilm formation genes. Mitochondrial aerobic respiration shift and endogenous ROS augmentation might be a major contribution to reduce mature biofilm metabolic activity. The data may be useful for the development of new strategies to reduce the incidence of device-associated infections. PMID:20383169

  12. Detection of methoxylated and hydroxylated polychlorinated biphenyls in sewage sludge in China with evidence for their microbial transformation

    PubMed Central

    Sun, Jianteng; Zhu, Lizhong; Pan, Lili; Wei, Zi; Song, Yao; Zhang, Yuduo; Qu, Liping; Zhan, Yu

    2016-01-01

    The concentrations of methoxylated polychlorinated biphenyls (MeO-PCBs) and hydroxylated polychlorinated biphenyls (OH-PCBs) were measured in the sewage sludge samples collected from twelve wastewater treatment plants in China. Two MeO-PCB congeners, including 3′-MeO-CB-65 and 4′-MeO-CB-101, were detected in three sludge with mean concentrations of 0.58 and 0.52 ng/g dry weight, respectively. OH-PCBs were detected in eight sludge samples, with an average total concentration of 4.2 ng/g dry weight. Furthermore, laboratory exposure was conducted to determine the possible source of OH-PCBs and MeO-PCBs in the sewage sludge, and their metabolism by the microbes. Both 4′-OH-CB-101 and 4′-MeO-CB-101 were detected as metabolites of CB-101 at a limited conversion rate after 5 days. Importantly, microbial interconversion between OH-PCBs and MeO-PCBs was observed in sewage sludge. Demethylation of MeO-PCBs was favored over methylation of OH-PCBs. The abundant and diverse microbes in sludge play a key role in the transformation processes of the PCB analogues. To our knowledge, this is the first report on MeO-PCBs in environmental matrices and on OH-PCBs in sewage sludge. The findings are important to understand the environmental fate of PCBs. PMID:27417462

  13. Detection of methoxylated and hydroxylated polychlorinated biphenyls in sewage sludge in China with evidence for their microbial transformation

    NASA Astrophysics Data System (ADS)

    Sun, Jianteng; Zhu, Lizhong; Pan, Lili; Wei, Zi; Song, Yao; Zhang, Yuduo; Qu, Liping; Zhan, Yu

    2016-07-01

    The concentrations of methoxylated polychlorinated biphenyls (MeO-PCBs) and hydroxylated polychlorinated biphenyls (OH-PCBs) were measured in the sewage sludge samples collected from twelve wastewater treatment plants in China. Two MeO-PCB congeners, including 3‧-MeO-CB-65 and 4‧-MeO-CB-101, were detected in three sludge with mean concentrations of 0.58 and 0.52 ng/g dry weight, respectively. OH-PCBs were detected in eight sludge samples, with an average total concentration of 4.2 ng/g dry weight. Furthermore, laboratory exposure was conducted to determine the possible source of OH-PCBs and MeO-PCBs in the sewage sludge, and their metabolism by the microbes. Both 4‧-OH-CB-101 and 4‧-MeO-CB-101 were detected as metabolites of CB-101 at a limited conversion rate after 5 days. Importantly, microbial interconversion between OH-PCBs and MeO-PCBs was observed in sewage sludge. Demethylation of MeO-PCBs was favored over methylation of OH-PCBs. The abundant and diverse microbes in sludge play a key role in the transformation processes of the PCB analogues. To our knowledge, this is the first report on MeO-PCBs in environmental matrices and on OH-PCBs in sewage sludge. The findings are important to understand the environmental fate of PCBs.

  14. Structure/Reactivity Relationships in the Benzo[c]phenanthrene Skeleton: Stable Ion and Electrophilic Substitution (Nitration, Bromination) Study of Substituted Analogs; Novel Carbocations and Substituted Derivatives

    PubMed Central

    Brulé, Cédric; Laali, Kenneth K.; Okazaki, Takao; Lakshman, Mahesh K.

    2008-01-01

    A series of novel carbocations were generated by low temperature protonation of substituted benzo[c]phenanthrenes B[c]Phs and their charge delocalization pathways were elucidated by NMR based on the magnitude of Δδ13C values. It has been shown that the protonation regioselectivity is strongly controlled by methoxy and hydroxyl substituents, whose directive effects override methyl substitution effects. Regiocontrol by –OMe and –OH substituents, and its stronger influence relative to methyl groups, was also observed in the nitration and bromination reactions. Charge distribution modes in the regioisomeric protonated carbocations via parent B[c]Ph as well as in the benzylic carbocation formed via fjord-region epoxide ring opening were deduced by GIAO-DFT, and from the NPA-derived changes in charges over CHs. These patterns were compared with those derived from NMR experiments in the substituted derivatives. NMR-based charge delocalization mapping provided insight into structure/activity relationships in the methylated and fluorinated B[c]Phs. Regioselectivities observed in the nitration and bromination reactions in representative cases are the same as those via protonations. Among a group of novel nitro and bromo derivatives synthesized in this study are examples where nitro group is introduced into the fjord-region, for which X-ray structure could be obtained in one case. PMID:17394355

  15. Vorticity in analog gravity

    NASA Astrophysics Data System (ADS)

    Cropp, Bethan; Liberati, Stefano; Turcati, Rodrigo

    2016-06-01

    In the analog gravity framework, the acoustic disturbances in a moving fluid can be described by an equation of motion identical to a relativistic scalar massless field propagating in curved space-time. This description is possible only when the fluid under consideration is barotropic, inviscid, and irrotational. In this case, the propagation of the perturbations is governed by an acoustic metric that depends algebrically on the local speed of sound, density, and the background flow velocity, the latter assumed to be vorticity-free. In this work we provide a straightforward extension in order to go beyond the irrotational constraint. Using a charged—relativistic and nonrelativistic—Bose-Einstein condensate as a physical system, we show that in the low-momentum limit and performing the eikonal approximation we can derive a d’Alembertian equation of motion for the charged phonons where the emergent acoustic metric depends on flow velocity in the presence of vorticity.

  16. Novel receptor-derived cyclopeptides to treat heart failure caused by anti-β1-adrenoceptor antibodies in a human-analogous rat model.

    PubMed

    Boivin, Valérie; Beyersdorf, Niklas; Palm, Dieter; Nikolaev, Viacheslav O; Schlipp, Angela; Müller, Justus; Schmidt, Doris; Kocoski, Vladimir; Kerkau, Thomas; Hünig, Thomas; Ertl, Georg; Lohse, Martin J; Jahns, Roland

    2015-01-01

    Despite recent therapeutic advances the prognosis of heart failure remains poor. Recent research suggests that heart failure is a heterogeneous syndrome and that many patients have stimulating auto-antibodies directed against the second extracellular loop of the β1 adrenergic receptor (β1EC2). In a human-analogous rat model such antibodies cause myocyte damage and heart failure. Here we used this model to test a novel antibody-directed strategy aiming to prevent and/or treat antibody-induced cardiomyopathy. To generate heart failure, we immunised n = 76/114 rats with a fusion protein containing the human β1EC2 (amino-acids 195-225) every 4 weeks; n = 38/114 rats were control-injected with 0.9% NaCl. Intravenous application of a novel cyclic peptide mimicking β1EC2 (β1EC2-CP, 1.0 mg/kg every 4 weeks) or administration of the β1-blocker bisoprolol (15 mg/kg/day orally) was initiated either 6 weeks (cardiac function still normal, prevention-study, n = 24 (16 treated vs. 8 untreated)) or 8.5 months after the 1st immunisation (onset of cardiomyopathy, therapy-study, n = 52 (40 treated vs. 12 untreated)); n = 8/52 rats from the therapy-study received β1EC2-CP/bisoprolol co-treatment. We found that β1EC2-CP prevented and (alone or as add-on drug) treated antibody-induced cardiac damage in the rat, and that its efficacy was superior to mono-treatment with bisoprolol, a standard drug in heart failure. While bisoprolol mono-therapy was able to stop disease-progression, β1EC2-CP mono-therapy -or as an add-on to bisoprolol- almost fully reversed antibody-induced cardiac damage. The cyclo¬peptide acted both by scavenging free anti-β1EC2-antibodies and by targeting β1EC2-specific memory B-cells involved in antibody-production. Our model provides the basis for the clinical translation of a novel double-acting therapeutic strategy that scavenges harmful anti-β1EC2-antibodies and also selectively depletes memory B-cells involved in the production of such antibodies

  17. Novel Receptor-Derived Cyclopeptides to Treat Heart Failure Caused by Anti-β1-Adrenoceptor Antibodies in a Human-Analogous Rat Model

    PubMed Central

    Boivin, Valérie; Beyersdorf, Niklas; Palm, Dieter; Nikolaev, Viacheslav O.; Schlipp, Angela; Müller, Justus; Schmidt, Doris; Kocoski, Vladimir; Kerkau, Thomas; Hünig, Thomas; Ertl, Georg; Lohse, Martin J.; Jahns, Roland

    2015-01-01

    Despite recent therapeutic advances the prognosis of heart failure remains poor. Recent research suggests that heart failure is a heterogeneous syndrome and that many patients have stimulating auto-antibodies directed against the second extracellular loop of the β1 adrenergic receptor (β1EC2). In a human-analogous rat model such antibodies cause myocyte damage and heart failure. Here we used this model to test a novel antibody-directed strategy aiming to prevent and/or treat antibody-induced cardiomyopathy. To generate heart failure, we immunised n = 76/114 rats with a fusion protein containing the human β1EC2 (amino-acids 195–225) every 4 weeks; n = 38/114 rats were control-injected with 0.9% NaCl. Intravenous application of a novel cyclic peptide mimicking β1EC2 (β1EC2-CP, 1.0 mg/kg every 4 weeks) or administration of the β1-blocker bisoprolol (15 mg/kg/day orally) was initiated either 6 weeks (cardiac function still normal, prevention-study, n = 24 (16 treated vs. 8 untreated)) or 8.5 months after the 1st immunisation (onset of cardiomyopathy, therapy-study, n = 52 (40 treated vs. 12 untreated)); n = 8/52 rats from the therapy-study received β1EC2-CP/bisoprolol co-treatment. We found that β1EC2-CP prevented and (alone or as add-on drug) treated antibody-induced cardiac damage in the rat, and that its efficacy was superior to mono-treatment with bisoprolol, a standard drug in heart failure. While bisoprolol mono-therapy was able to stop disease-progression, β1EC2-CP mono-therapy -or as an add-on to bisoprolol- almost fully reversed antibody-induced cardiac damage. The cyclo¬peptide acted both by scavenging free anti-β1EC2-antibodies and by targeting β1EC2-specific memory B-cells involved in antibody-production. Our model provides the basis for the clinical translation of a novel double-acting therapeutic strategy that scavenges harmful anti-β1EC2-antibodies and also selectively depletes memory B-cells involved in the production of such antibodies

  18. Novel daidzein analogs enhance osteogenic activity of bone marrow-derived mesenchymal stem cells and adipose-derived stromal/stem cells through estrogen receptor dependent and independent mechanisms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Osteoporosis is a disease characterized by low bone mineral density (BMD) and increased risk of fractures. Studies have demonstrated the use of phytoestrogens, or plant-derived estrogens, such as genistein anddaidzein, to effectively increase osteogenic activity of bone marrow-derived mesenchymal s...

  19. Matrix solid-phase dispersion of polybrominated diphenyl ethers and their hydroxylated and methoxylated analogues in lettuce, carrot and soil.

    PubMed

    Iparraguirre, A; Rodil, R; Quintana, J B; Bizkarguenaga, E; Prieto, A; Zuloaga, O; Cela, R; Fernández, L A

    2014-09-19

    In the present work, a novel analytical method for the simultaneous determination of ten polybrominated diphenyl ethers (PBDEs), eight methoxylated PBDEs (MeO-PBDEs) and seven hydroxylated PBDEs (OH-PBDEs) in soil, lettuce and carrot samples was developed. The procedure was based on matrix solid-phase dispersion (MSPD) followed by gas chromatography coupled to negative chemical ionization-mass spectrometry (GC-NCI-MS). Under optimum conditions, 0.5g of sample (freeze-dried in the case of lettuce and carrot samples) was dispersed with 0.5g of octadecyl-functionalized silica (C18) and 1.75g of acidified silica (10% H2SO4, w/w) was used as clean-up sorbent. A two-step fractionated elution was carried out. First, PBDEs and MeO-PBDEs were eluted in 75:25% (v/v) n-hexane/dichloromethane mixture and, then, the retained OH-PBDEs were eluted in pure dichloromethane. Both extracts were analyzed by GC-NCI-MS separately, in the case of OH-PBDEs after derivatization with N-methyl-N-(trimethylsilyl) trifluoroacetamide. The developed method was validated in terms of accuracy for soil, lettuce and carrot matrices, spiked at two fortification levels (5 and 25ngg(-1)). After correction with the corresponding surrogate, apparent recovery values (defined as the recovery obtained after correction with the corresponding surrogate) were in the 80-129% range. Precision (as relative standard deviation) in the 1-21% range and method detection limits (MDLs) in the 0.003 and 0.3ngg(-1) range for soil and in the 0.003-0.4ngg(-1) range (dry weight) for lettuce and carrot samples were obtained. For PBDEs the method was also validated with a standard reference material (SRM-2585) of house dust. Finally, the method was applied for the determination of target analytes in soil, lettuce and carrot.

  20. Synthesis and Photophysical Properties of a 13,13'-Bibenzo[b]perylenyl Derivative as a π-Extended 1,1'-Binaphthyl Analog.

    PubMed

    Uchida, Yosuke; Hirose, Takashi; Nakashima, Takuya; Kawai, Tsuyoshi; Matsuda, Kenji

    2016-05-01

    A 13,13'-bibenzo[b]perylenyl derivative-an axially chiral π-extended compound in which two perylene subunits fused to 1,1'-binaphthyl scaffold-has been synthesized from 1,8-dibromophenanthrene using an anionic cyclodehydrogenation reaction in the presence of potassium metal as the key step. The pair of enantiomers can be separated by chiral high-performance liquid chromatography (HPLC), which showed a strong circular dichroism (CD) (Δε = 330 M(-1) cm(-1) at 449 nm, |gCD| = 5.8 × 10(-3) at 453 nm), high fluorescence quantum yield (Φf = 64%), and strong circular polarized luminescence (CPL) (|gCPL| = 5 × 10(-3) at 454 nm) in solution phase.

  1. Radioactive Decay - An Analog.

    ERIC Educational Resources Information Center

    McGeachy, Frank

    1988-01-01

    Presents an analog of radioactive decay that allows the student to grasp the concept of half life and the exponential nature of the decay process. The analog is devised to use small, colored, plastic poker chips or counters. Provides the typical data and a graph which supports the analog. (YP)

  2. In vitro and in vivo modulation of ABCG2 by functionalized aurones and structurally related analogs

    PubMed Central

    Sim, Hong-May; Wu, Chung-Pu; Ambudkar, Suresh V.; Go, Mei-Lin

    2013-01-01

    Over-expression of ABCG2 is linked to multidrug resistance in cancer chemotherapy. We have previously shown that functionalized aurones effectively reduced the efflux of pheophorbide A (an ABCG2 substrate) from ABCG2 over-expressing MDA-MB-231/R (“R”) cells. In the present report, we investigated the functional relevance of this observation and the mechanisms by which it occurs. Aurones and related analogs were investigated for re-sensitization of R cells to mitoxantrone (MX, a chemotherapeutic substrate of ABCG2) in cell-based assays, accumulation of intracellular MX by cell cytometry, interaction with ABCG2 by biochemical assays and in vivo efficacy in MX resistant nude mice xenografts. We found that methoxylated aurones interacted directly with ABCG2 to inhibit efflux activity, possibly by competing for occupancy of one of the substrate binding sites on ABCG2. The present evidence suggests that they are not transported by ABCG2 although they stimulate ABCG2-ATPase activity. Alteration of ABCG2 protein expression was also discounted. One member was found to re-sensitize R cells to MX in both in vitro and in vivo settings. Our study identified methoxylated aurones as promising compounds associated with low toxicities and potent modulatory effects on the ABCG2 efflux protein. Thus, they warrant further scrutiny as lead templates for development as reversal agents of multidrug resistance. PMID:21855533

  3. Synthesis, physicochemical, and anticonvulsant properties of new N-Mannich bases derived from pyrrolidine-2,5-dione and its 3-methyl analog.

    PubMed

    Rybka, Sabina; Obniska, Jolanta; Rapacz, Anna; Filipek, Barbara; Kamiński, Krzysztof

    2014-10-01

    A series of 22 new N-[(4-phenylpiperazin-1-yl)-methyl]-3-methyl-pyrrolidine-2,5-dione and pyrrolidine-2,5-dione derivatives were synthesized and evaluated for their anticonvulsant activities in the maximum electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) seizure tests after intraperitoneal injection into mice. The neurotoxicity was determined applying the rotarod test. The in vivo results in mice showed that seven compounds were effective in the MES or/and scPTZ seizure tests. The quantitative evaluation in both tests after i.p. administration into mice revealed that the most active compounds were N-[{4-(3,4-dichlorophenyl)-piperazin-1-yl}-methyl]-3-methylpyrrolidine-2,5-dione (12) with ED50  = 16.13 mg/kg (MES), ED50  = 133.99 mg/kg (scPTZ) and N-[{4-(3,4-dichlorophenyl)-piperazin-1-yl}-methyl]-pyrrolidine-2,5-dione (23) with ED50  = 37.79 mg/kg (MES), ED50  = 128.82 mg/kg (scPTZ), whereas N-[{4-(3-trifluoromethylphenyl)-piperazin-1-yl}-methyl]-pyrrolidine-2,5-dione (24) was effective only in the MES test with ED50  = 16.37 mg/kg. These molecules showed higher potency and also lower neurotoxicity than the reference antiepileptic drugs such as ethosuximide and valproic acid. PMID:25139813

  4. Preliminary results for potential climatic signals in dD of wood lignin methoxyl groups from high-elevation alpine larch trees

    NASA Astrophysics Data System (ADS)

    Reichelmann, Dana F. C.; Greule, Markus; Esper, Jan; Keppler, Frank

    2016-04-01

    Tree-rings of high alpine larch trees (Larix decidua) were investigated using a recently established method that measures dD values of the wood lignin methoxyl groups (Greule et al. 2008). The resulting dD time series were tested for their potential to preserve climatic signals. 37 larch trees were sampled at the tree line near Simplon Village (Southern Switzerland). They were analysed for their tree-ring width (TRW), and from five individuals dD of the wood lignin methoxyl groups (dDmethoxyl) were measured at annual resolution from 1971-2009 and at pentadal resolution from 1781-2009. The inter-series correlation of the five annually resolved dDmethoxyl series is 0.53 (p < 0.001). For the five pentadally resolved dDmethoxyl series no significant inter-series correlation could be determined. The dDmethoxyl series (annually and pentadally) show a negative correlation with tree-ring width of r = -0.53 (p < 0.001) and r = -0.32 (p < 0.05), respectively. The climate response of the new dDmethoxyl proxy shows a significant correlation of r = 0.60 for the annually resolved data with June to July precipitation. The pentadally resolved dDmethoxyl series do not show any significant correlation neither with temperature nor precipitation. These results probably indicate dDmethoxyl as a precipitation proxy for high-alpine sites. The missing climate signal in the pentadally resolved series is probably due to absent long term trends in precipitation, which have stronger year to year variability. References: Greule, M., Mosandl, A., Hamilton, J.T.G., Keppler, F., 2008. A rapid and precise method for determination of D/H ratios of plant methoxyl groups. Rapid Communications in Mass Spectrometry, 22(24): 3983-3988.

  5. Analog, still without fear

    NASA Astrophysics Data System (ADS)

    Delagrange, A. D.

    1984-09-01

    This report is an update of one issued in 1977 which predicted that the predicted death of analog circuitry (also called linear) would not occur; in fact, the patient appeared remarkably healthy. The report proved correct. We have the same situation again today: the same predictions and counter-prediction. Each year brings significant advances in the field of analog integrated circuitry. Many of the traditional arguments against analog circuitry are no longer valid. This report attempts to summarize what is available now, and what can (and cannot) be done with analog integrated circuits. It defines analog and makes some comparisons with digital. The most common types of analog integrated circuits are then listed and discussed. Lastly, some design and trouble-shooting hints are given, and the state-of-the-art is discussed.

  6. Nonvolatile Analog Memory

    NASA Technical Reports Server (NTRS)

    MacLeod, Todd C. (Inventor)

    2007-01-01

    A nonvolatile analog memory uses pairs of ferroelectric field effect transistors (FFETs). Each pair is defined by a first FFET and a second FFET. When an analog value is to be stored in one of the pairs, the first FFET has a saturation voltage applied thereto, and the second FFET has a storage voltage applied thereto that is indicative of the analog value. The saturation and storage voltages decay over time in accordance with a known decay function that is used to recover the original analog value when the pair of FFETs is read.

  7. Analog synthetic biology.

    PubMed

    Sarpeshkar, R

    2014-03-28

    We analyse the pros and cons of analog versus digital computation in living cells. Our analysis is based on fundamental laws of noise in gene and protein expression, which set limits on the energy, time, space, molecular count and part-count resources needed to compute at a given level of precision. We conclude that analog computation is significantly more efficient in its use of resources than deterministic digital computation even at relatively high levels of precision in the cell. Based on this analysis, we conclude that synthetic biology must use analog, collective analog, probabilistic and hybrid analog-digital computational approaches; otherwise, even relatively simple synthetic computations in cells such as addition will exceed energy and molecular-count budgets. We present schematics for efficiently representing analog DNA-protein computation in cells. Analog electronic flow in subthreshold transistors and analog molecular flux in chemical reactions obey Boltzmann exponential laws of thermodynamics and are described by astoundingly similar logarithmic electrochemical potentials. Therefore, cytomorphic circuits can help to map circuit designs between electronic and biochemical domains. We review recent work that uses positive-feedback linearization circuits to architect wide-dynamic-range logarithmic analog computation in Escherichia coli using three transcription factors, nearly two orders of magnitude more efficient in parts than prior digital implementations. PMID:24567476

  8. Hydraulic Capacitor Analogy

    ERIC Educational Resources Information Center

    Baser, Mustafa

    2007-01-01

    Students have difficulties in physics because of the abstract nature of concepts and principles. One of the effective methods for overcoming students' difficulties is the use of analogies to visualize abstract concepts to promote conceptual understanding. According to Iding, analogies are consistent with the tenets of constructivist learning…

  9. Analog synthetic biology

    PubMed Central

    Sarpeshkar, R.

    2014-01-01

    We analyse the pros and cons of analog versus digital computation in living cells. Our analysis is based on fundamental laws of noise in gene and protein expression, which set limits on the energy, time, space, molecular count and part-count resources needed to compute at a given level of precision. We conclude that analog computation is significantly more efficient in its use of resources than deterministic digital computation even at relatively high levels of precision in the cell. Based on this analysis, we conclude that synthetic biology must use analog, collective analog, probabilistic and hybrid analog–digital computational approaches; otherwise, even relatively simple synthetic computations in cells such as addition will exceed energy and molecular-count budgets. We present schematics for efficiently representing analog DNA–protein computation in cells. Analog electronic flow in subthreshold transistors and analog molecular flux in chemical reactions obey Boltzmann exponential laws of thermodynamics and are described by astoundingly similar logarithmic electrochemical potentials. Therefore, cytomorphic circuits can help to map circuit designs between electronic and biochemical domains. We review recent work that uses positive-feedback linearization circuits to architect wide-dynamic-range logarithmic analog computation in Escherichia coli using three transcription factors, nearly two orders of magnitude more efficient in parts than prior digital implementations. PMID:24567476

  10. Challenges in Using Analogies

    ERIC Educational Resources Information Center

    Lin, Shih-Yin; Singh, Chandralekha

    2011-01-01

    Learning physics requires understanding the applicability of fundamental principles in a variety of contexts that share deep features. One way to help students learn physics is via analogical reasoning. Students can be taught to make an analogy between situations that are more familiar or easier to understand and another situation where the same…

  11. Meat analog: a review.

    PubMed

    Malav, O P; Talukder, S; Gokulakrishnan, P; Chand, S

    2015-01-01

    The health-conscious consumers are in search of nutritious and convenient food item which can be best suited in their busy life. The vegetarianism is the key for the search of such food which resembles the meat in respect of nutrition and sensory characters, but not of animal origin and contains vegetable or its modified form, this is the point when meat analog evolved out and gets shape. The consumers gets full satisfaction by consumption of meat analog due to its typical meaty texture, appearance and the flavor which are being imparted during the skilled production of meat analog. The supplement of protein in vegetarian diet through meat alike food can be fulfilled by incorporating protein-rich vegetative food grade materials in meat analog and by adopting proper technological process which can promote the proper fabrication of meat analog with acceptable meat like texture, appearance, flavor, etc. The easily available vegetables, cereals, and pulses in India have great advantages and prospects to be used in food products and it can improve the nutritional and functional characters of the food items. The various form and functional characters of food items are available world over and attracts the meat technologists and the food processors to bring some innovativeness in meat analog and its presentation and marketability so that the acceptability of meat analog can be overgrown by the consumers.

  12. Challenges in Using Analogies

    NASA Astrophysics Data System (ADS)

    Lin, Shih-Yin; Singh, Chandralekha

    2011-11-01

    Learning physics requires understanding the applicability of fundamental principles in a variety of contexts that share deep features.1-7 One way to help students learn physics is via analogical reasoning. Students can be taught to make an analogy between situations that are more familiar or easier to understand and another situation where the same physics principle is involved but that is more difficult to handle. Here, we examine introductory physics students' ability to use analogies in solving problems involving Newton's second law. Students enrolled in an algebra-based introductory physics course were given a solved problem involving tension in a rope and were then asked to solve another problem for which the physics is very similar but involved a frictional force. They were asked to point out the similarities between the two problems and then use the analogy to solve the friction problem.

  13. Fatty acid analogs

    DOEpatents

    Elmaleh, David R.; Livni, Eli

    1985-01-01

    In one aspect, a radioactively labeled analog of a fatty acid which is capable of being taken up by mammalian tissue and which exhibits an in vivo beta-oxidation rate below that with a corresponding radioactively labeled fatty acid.

  14. Analogies as categorization phenomena: Studies from scientific discourse

    NASA Astrophysics Data System (ADS)

    Atkins, Leslie Jill

    Studies on the role of analogies in science classrooms have tended to focus on analogies that come from the teacher or curriculum, and not the analogies that students generate. Such studies are derivative of an educational system that values content knowledge over scientific creativity, and derivative of a model of teaching in which the teacher's role is to convey content knowledge. This dissertation begins with the contention that science classrooms should encourage scientific thinking and one role of the teacher is to model that behavior and identify and encourage it in her students. One element of scientific thinking is analogy. This dissertation focuses on student-generated analogies in science, and offers a model for understanding these. I provide evidence that generated analogies are assertions of categorization, and the base of an analogy is the constructed prototype of an ad hoc category. Drawing from research on categorization, I argue that generated analogies are based in schemas and cognitive models. This model allows for a clear distinction between analogy and literal similarity; prior to this research analogy has been considered to exist on a spectrum of similarity, differing from literal similarity to the degree that structural relations hold but features do not. I argue for a definition in which generated analogies are an assertion of an unexpected categorization: that is, they are asserted as contradictions to an expected schema.

  15. FGF growth factor analogs

    DOEpatents

    Zamora, Paul O.; Pena, Louis A.; Lin, Xinhua; Takahashi, Kazuyuki

    2012-07-24

    The present invention provides a fibroblast growth factor heparin-binding analog of the formula: ##STR00001## where R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, Y and Z are as defined, pharmaceutical compositions, coating compositions and medical devices including the fibroblast growth factor heparin-binding analog of the foregoing formula, and methods and uses thereof.

  16. Distribution and binding of novel photosensitizer 2-devinyl-2-(1-methoxyl-ethyl) chlorin f in human breast cancer cells MCF-7

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Chen, P.; Zhang, F.; Lin, L.; Tang, G.-Q.; Mu, G.-G.

    2009-06-01

    The interaction of novel Photosensitizer 2-devinyl-2-(1-methoxyl-ethyl) chlorin f (CPD4) with human breast cancer cells MCF-7 was studied by fluorescence spectrum and laser confocal scan microscopy (LCSM). The experimental results exhibit that fluorescence emission band of CPD4 in MCF-7 cells move to long wavelength about 5 nm compared with that in incubation solution, which suggest that CPD4 could enter into MCF-7 cells and bind them strongly by electrostatic or hydrogen binding interaction. The LCSM images of CPD4 in MCF-7 cells show that the binding of CPD4 in MCF-7 cells takes place in cellular membrane and mitochondria mainly. These results indicate that CPD4 can be of selective subcellular location, but not free ionic status in MCF-7 cells.CPD4 could be a kind of promising photosensitizer for Photodynamic therapy.

  17. Gravito-electromagnetic analogies

    NASA Astrophysics Data System (ADS)

    Costa, L. Filipe O.; Natário, José

    2014-10-01

    We reexamine and further develop different gravito-electromagnetic (GEM) analogies found in the literature, and clarify the connection between them. Special emphasis is placed in two exact physical analogies: the analogy based on inertial fields from the so-called "1+3 formalism", and the analogy based on tidal tensors. Both are reformulated, extended and generalized. We write in both formalisms the Maxwell and the full exact Einstein field equations with sources, plus the algebraic Bianchi identities, which are cast as the source-free equations for the gravitational field. New results within each approach are unveiled. The well known analogy between linearized gravity and electromagnetism in Lorentz frames is obtained as a limiting case of the exact ones. The formal analogies between the Maxwell and Weyl tensors are also discussed, and, together with insight from the other approaches, used to physically interpret gravitational radiation. The precise conditions under which a similarity between gravity and electromagnetism occurs are discussed, and we conclude by summarizing the main outcome of each approach.

  18. Low-methoxyl pectin stimulates small intestinal mucin secretion irrespective of goblet cell proliferation and is characterized by jejunum Muc2 upregulation in rats.

    PubMed

    Hino, Shingo; Sonoyama, Kei; Bito, Hiroyuki; Kawagishi, Hirokazu; Aoe, Seiichiro; Morita, Tatsuya

    2013-01-01

    Generally, soluble fibers increase small intestinal mucin secretion by increasing the number of goblet cells in a viscosity-dependent manner. The present study aimed to examine the mechanism by which low-methoxyl pectin (LPC) affects mucin secretion in the small intestine. First, diets containing 50 g/kg of low-viscosity fiber (LPC, gum arabic, guar gum, low-molecular konjac mannan, arabinogalactan, sodium alginate) or high-molecular konjac mannan (KMH) were fed to Wistar rats for 10 d. Luminal mucin was greater in the LPC and KMH groups than in the fiber-free control group, but only the KMH group had more goblet cells in the ileum compared with the other groups. Next, Sprague-Dawley rats were fed LPC, KMH, or high-methoxyl pectin (HPC) diets (50 g/kg) for 10 d. The KMH and LPC groups, but not the HPC group, had greater luminal mucin than the control group, whereas jejunum Muc2 expression was higher only in the LPC group. Sprague-Dawley rats fed the LPC diet for 1 or 3 d had greater luminal mucin and jejunum Muc2 expression than those fed the control diet. In vitro studies using HT-29MTX cells showed that, of the various fibers studied, only LPC and HPC affected mucin secretion. Finally, Wistar rats were fed the LPC diet with or without neomycin in drinking water for 10 d; neomycin treatment did not compromise the effect of LPC on mucin secretion. We conclude that LPC does not affect the number of goblet cells but can interact directly with the epithelium and stimulate small intestinal mucin secretion.

  19. Electrical Circuits and Water Analogies

    ERIC Educational Resources Information Center

    Smith, Frederick A.; Wilson, Jerry D.

    1974-01-01

    Briefly describes water analogies for electrical circuits and presents plans for the construction of apparatus to demonstrate these analogies. Demonstrations include series circuits, parallel circuits, and capacitors. (GS)

  20. Novel stilbene-based Fischer base analog of leuco-TAM - (2E,2'Z)-{2-(4-(E)-styrylphenyl)propane-1,3-diylidene}bis(1,3,3-trimethylindoline) - derivatives: synthesis and structural consideration by 1D NMR and 2D NMR spectroscopy.

    PubMed

    Keum, Sam-Rok; Lim, Hyun-Woo

    2016-02-01

    We report the synthesis of a series of novel stilbene-based (St) Fischer base analogs of leuco-triarylmethane (LTAM) dyes by treating Fischer base with (E)-4-styrylbenzaldehyde derivatives. All St-LTAM molecules examined herein are characterized by 1D and 2D NMR. They were found to exhibit ZE configuration and isomerize to their diastereomers EE and ZZ in 2-3 h. They exhibit type I behavior of diastereomeric isomerization. PMID:26448377

  1. Polysubstituted pyrazoles, part 5. Synthesis of new 1-(4-chlorophenyl)-4-hydroxy-1H-pyrazole-3-carboxylic acid hydrazide analogs and some derived ring systems. A novel class of potential antitumor and anti-HCV agents.

    PubMed

    Rostom, Sherif A F; Shalaby, Manal A; El-Demellawy, Maha A

    2003-01-01

    A novel series of 1-(4-chlorophenyl)-4-hydroxy-1H-pyrazole-3-carboxylic acid hydrazide analogs and some derived 4-substituted-1,2,4-triazolin-3-thiones, 2-substituted-1,3,4-thiadiazole and 2-substituted-1,3,4-oxadiazoles has been synthesized. Ten of the newly synthesized compounds were selected by the National Cancer Institute (NCI)-in vitro-disease oriented antitumor screening to be evaluated for their antitumor activity. Seven compounds, namely 7a-c, 9, 11, 13 and 14, exhibited potential and broad spectrum antitumor activity against most of the tested subpanel tumour cell lines (GI50<100 microM). Compounds 14 (GI50, TGI, and LC50 MG-MID values of 0.08, 15.8 and 64.6 microM, respectively) and 11 (GI50, TGI, and LC50 MG-MID values of 0.20, 11.7 and 87.1 microM, respectively) proved to be the most active members in this study with potential activity against all the tested subpanel tumour cell lines and particular effectiveness on the leukaemia subpanel at both the GI50 (0.03 and 0.09 microM, respectively) and the TGI levels (35.2 and 28.1 microM, respectively). Moreover, compound 14 exhibited a super sensitivity profile towards about 26 different cancer cell lines with GI50 values lying in the nanomolar concentration range (GI50 values<0.01 microM). In addition, compounds 2-5, 6a-d, 7a, 8-11, 12a, 13, 14 were investigated for their in vitro effect on the replication of hepatitis-C virus (HCV) in HepG2 hepatocellular carcinoma cell line infected with the virus using the reverse transcription-polymerase chain reaction (RT-PCR) technique. The results revealed that compounds 2 and 5 were capable of inhibiting the replication of both the HCV RNA (+) and (-) strands at 10-100 microg mL(-1) concentration range.

  2. Development of analogical problem-solving skill.

    PubMed

    Holyoak, K J; Junn, E N; Billman, D O

    1984-12-01

    3 experiments were performed to assess children's ability to solve a problem by analogy to a superficially dissimilar situation. Preschoolers and fifth and sixth graders were asked to solve a problem that allowed multiple solutions. Some subjects were first read a story that included an analogous problem and its solution. When the mapping between the relations involved in the corresponding solutions was relatively simple, and the corresponding instruments were perceptually and functionally similar, even preschoolers were able to use the analogy to derive a solution to the transfer problem (Experiment 1). Furthermore, salient similarity of the instruments was neither sufficient (Experiment 2) nor necessary (Experiment 3) for success by preschool subjects. When the story analog mapped well onto the transfer problem, 4-year-olds were often able to generate a solution that required transformation of an object with little perceptual or semantic similarity to the instrument used in the base analog (Experiment 3). The older children used analogies in a manner qualitatively similar to that observed in comparable studies with adults (Experiment 1), whereas the younger children exhibited different limitations.

  3. Electrical analogous in viscoelasticity

    NASA Astrophysics Data System (ADS)

    Ala, Guido; Di Paola, Mario; Francomano, Elisa; Li, Yan; Pinnola, Francesco P.

    2014-07-01

    In this paper, electrical analogous models of fractional hereditary materials are introduced. Based on recent works by the authors, mechanical models of materials viscoelasticity behavior are firstly approached by using fractional mathematical operators. Viscoelastic models have elastic and viscous components which are obtained by combining springs and dashpots. Various arrangements of these elements can be used, and all of these viscoelastic models can be equivalently modeled as electrical circuits, where the spring and dashpot are analogous to the capacitance and resistance, respectively. The proposed models are validated by using modal analysis. Moreover, a comparison with numerical experiments based on finite difference time domain method shows that, for long time simulations, the correct time behavior can be obtained only with modal analysis. The use of electrical analogous in viscoelasticity can better reveal the real behavior of fractional hereditary materials.

  4. Analogical Reasoning in Geometry Education

    ERIC Educational Resources Information Center

    Magdas, Ioana

    2015-01-01

    The analogical reasoning isn't used only in mathematics but also in everyday life. In this article we approach the analogical reasoning in Geometry Education. The novelty of this article is a classification of geometrical analogies by reasoning type and their exemplification. Our classification includes: analogies for understanding and setting a…

  5. Digital and analog communication systems

    NASA Technical Reports Server (NTRS)

    Shanmugam, K. S.

    1979-01-01

    The book presents an introductory treatment of digital and analog communication systems with emphasis on digital systems. Attention is given to the following topics: systems and signal analysis, random signal theory, information and channel capacity, baseband data transmission, analog signal transmission, noise in analog communication systems, digital carrier modulation schemes, error control coding, and the digital transmission of analog signals.

  6. Solid-phase synthesis of prenylcysteine analogs

    PubMed Central

    Donelson, James L.; Hodges-Loaiza, Heather B.; Henriksen, Brian S.; Hrycyna, Christine A.

    2009-01-01

    Prenylcysteine derivatives are of interest for a variety of different biological reasons, including probing the CaaX protein processing pathway. A solid-phase synthesis protocol for the preparation of prenylcysteines using 2-chlorotrityl chloride resin as a solid support has been developed. A series of novel amide-modified farnesylcysteine analogs were synthesized in both high purity and yield under mild conditions. The farnesylcysteine analogs were evaluated using human isoprenylcysteine carboxyl methyltransferase (Icmt) as a biological target, and several new inhibitors, one with significantly enhanced potency, were identified. PMID:19320430

  7. Arterial Pressure Analog.

    ERIC Educational Resources Information Center

    Heusner, A. A.; Tracy, M. L.

    1980-01-01

    Describes a simple hydraulic analog which allows students to explore some physical aspects of the cardiovascular system and provides them with a means to visualize and conceptualize these basic principles. Simulates the behavior of arterial pressure in response to changes in heart rate, stroke volume, arterial compliance, and peripheral…

  8. Quantum Analog Computing

    NASA Technical Reports Server (NTRS)

    Zak, M.

    1998-01-01

    Quantum analog computing is based upon similarity between mathematical formalism of quantum mechanics and phenomena to be computed. It exploits a dynamical convergence of several competing phenomena to an attractor which can represent an externum of a function, an image, a solution to a system of ODE, or a stochastic process.

  9. Reasoning through Instructional Analogies

    ERIC Educational Resources Information Center

    Kapon, Shulamit; diSessa, Andrea A.

    2012-01-01

    This article aims to account for students' assessments of the plausibility and applicability of analogical explanations, and individual differences in these assessments, by analyzing properties of students' underlying knowledge systems. We developed a model of explanation and change in explanation focusing on knowledge elements that provide a…

  10. How Analogy Drives Physics

    SciTech Connect

    Hofstadter, Doug

    2004-05-05

    Many new ideas in theoretical physics come from analogies to older ideas in physics. For instance, the abstract notion of 'isospin' (or isotopic spin) originated in the prior concept of 'spin' (quantized angular momentum); likewise, the concept of 'phonon' (quantum of sound, or quantized collective excitation of a crystal) was based on the prior concept of 'photon' (quantum of light, or quantized element of the electromagnetic field). But these two examples, far from being exceptions, in fact represent the bread and butter of inventive thinking in physics. In a nutshell, intraphysics analogy-making -- borrowing by analogy with something already known in another area of physics -- is central to the progress of physics. The aim of this talk is to reveal the pervasiveness -- indeed, the indispensability -- of this kind of semi-irrational, wholly intuitive type of thinking (as opposed to more deductive mathematical inference) in the mental activity known as 'doing physics'. Speculations as to why wild analogical leaps are so crucial to the act of discovery in physics (as opposed to other disciplines) will be offered.

  11. Analog signal isolation techniques

    SciTech Connect

    Beadle, E.R.

    1992-12-31

    This paper discusses several techniques for isolating analog signals in an accelerator environment. The techniques presented here encompass isolation amplifiers, voltage-to-frequency converters (VIFCs), transformers, optocouplers, discrete fiber optics, and commercial fiber optic links. Included within the presentation of each method are the design issues that must be considered when selecting the isolation method for a specific application.

  12. Analog signal isolation techniques

    SciTech Connect

    Beadle, E.R.

    1992-01-01

    This paper discusses several techniques for isolating analog signals in an accelerator environment. The techniques presented here encompass isolation amplifiers, voltage-to-frequency converters (VIFCs), transformers, optocouplers, discrete fiber optics, and commercial fiber optic links. Included within the presentation of each method are the design issues that must be considered when selecting the isolation method for a specific application.

  13. Inhibition of cancer growth and induction of apoptosis by BGP-13 and BGP-15, new calcipotriene-derived vitamin D3 analogs, in-vitro and in-vivo studies.

    PubMed

    Berkovich, Liron; Sintov, Amnon C; Ben-Shabat, Shimon

    2013-04-01

    One of the most innovative approaches to the treatment of cancer entails the use of 1α,25-dihydroxyvitamin D3 (calcitriol) analogs to inhibit cancer cell growth. We demonstrate here that BGP-13, a new calcipotriene-based 1α,25-dihydroxyvitamin D3 analog that we synthesized in our laboratory, inhibits the growth of prostate cancer (LNCaP), breast cancer (MCF-7), and colon cancer (HT-29) cell lines. Moreover, we also show that BGP-13 causes cells both to accumulate in G0-G1 and to activate caspase-3 and undergo apoptosis. In addition, we observed elevated vitamin D receptor (VDR) mRNA and protein levels in both LNCaP and MCF-7 cells following the exposure of the two cell lines to BGP-13. Importantly, we found that both the new analog BGP-13 and also BGP-15, another calcipotriene-based analog we synthesized previously and about which we published recently, inhibit the growth of HT-29 tumor xenografts in nude mice.

  14. Gravitoelectromagnetic analogy based on tidal tensors

    SciTech Connect

    Costa, L. Filipe O.; Herdeiro, Carlos A. R.

    2008-07-15

    We propose a new approach to a physical analogy between general relativity and electromagnetism, based on tidal tensors of both theories. Using this approach we write a covariant form for the gravitational analogues of the Maxwell equations, which makes transparent both the similarities and key differences between the two interactions. The following realizations of the analogy are given. The first one matches linearized gravitational tidal tensors to exact electromagnetic tidal tensors in Minkowski spacetime. The second one matches exact magnetic gravitational tidal tensors for ultrastationary metrics to exact magnetic tidal tensors of electromagnetism in curved spaces. In the third we show that our approach leads to a two-step exact derivation of Papapetrou's equation describing the force exerted on a spinning test particle. Analogous scalar invariants built from tidal tensors of both theories are also discussed.

  15. Terrestrial Spaceflight Analogs: Antarctica

    NASA Technical Reports Server (NTRS)

    Crucian, Brian

    2013-01-01

    Alterations in immune cell distribution and function, circadian misalignment, stress and latent viral reactivation appear to persist during Antarctic winterover at Concordia Station. Some of these changes are similar to those observed in Astronauts, either during or immediately following spaceflight. Others are unique to the Concordia analog. Based on some initial immune data and environmental conditions, Concordia winterover may be an appropriate analog for some flight-associated immune system changes and mission stress effects. An ongoing smaller control study at Neumayer III will address the influence of the hypoxic variable. Changes were observed in the peripheral blood leukocyte distribution consistent with immune mobilization, and similar to those observed during spaceflight. Alterations in cytokine production profiles were observed during winterover that are distinct from those observed during spaceflight, but potentially consistent with those observed during persistent hypobaric hypoxia. The reactivation of latent herpesviruses was observed during overwinter/isolation, that is consistently associated with dysregulation in immune function.

  16. Analog storage integrated circuit

    DOEpatents

    Walker, J. T.; Larsen, R. S.; Shapiro, S. L.

    1989-01-01

    A high speed data storage array is defined utilizing a unique cell design for high speed sampling of a rapidly changing signal. Each cell of the array includes two input gates between the signal input and a storage capacitor. The gates are controlled by a high speed row clock and low speed column clock so that the instantaneous analog value of the signal is only sampled and stored by each cell on coincidence of the two clocks.

  17. Antarctic analogs for Enceladus

    NASA Astrophysics Data System (ADS)

    Murray, A. E.; Andersen, D. T.; McKay, C. P.

    2014-12-01

    Enceladus is a new world for Astrobiology. The Cassini discovery of the icy plume emanating from the South Polar region indicates an active world, where detection of water, organics, sodium, and nano-particle silica in the plume strongly suggests that the source is a subsurface salty ocean reservoir. Recent gravity data from Cassini confirms the presence of a regional sea extending north to 50°S. An ocean habitat under a thick ice cover is perhaps a recurring theme in the Outer Solar System, but what makes Enceladus unique is that the plume jetting out into space is carrying samples of this ocean. Therefore, through the study of Enceladus' plumes we can gain new insights not only of a possible habitable world in the Solar Systems, but also about the formation and evolution of other icy-satellites. Cassini has been able to fly through this plume - effectively sampling the ocean. It is time to plan for future missions that do more detailed analyses, possibly return samples back to Earth and search for evidence of life. To help prepare for such missions, the need for earth-based analog environments is essential for logistical, methodological (life detection) and theoretical development. We have undertaken studies of two terrestrial environments that are close analogs to Enceladus' ocean: Lake Vida and Lake Untersee - two ice-sealed Antarctic lakes that represent physical, chemical and possibly biological analogs for Enceladus. By studying the diverse biology and physical and chemical constraints to life in these two unique lakes we will begin to understand the potential habitability of Enceladus and other icy moons, including possible sources of nutrients and energy, which together with liquid water are the key ingredients for life. Analog research such as this will also enable us to develop and test new strategies to search for evidence of life on Enceladus.

  18. Analog storage integrated circuit

    DOEpatents

    Walker, J.T.; Larsen, R.S.; Shapiro, S.L.

    1989-03-07

    A high speed data storage array is defined utilizing a unique cell design for high speed sampling of a rapidly changing signal. Each cell of the array includes two input gates between the signal input and a storage capacitor. The gates are controlled by a high speed row clock and low speed column clock so that the instantaneous analog value of the signal is only sampled and stored by each cell on coincidence of the two clocks. 6 figs.

  19. The promise of analog computation

    NASA Astrophysics Data System (ADS)

    MacLennan, B. J.

    2014-10-01

    Future computing paradigms and technologies will have to be more like the physical processes by which they are realized, and because these processes are primarily continuous, post-Moore's law computing will involve an increased use of analog computation. Traditionally analog computers have computed ordinary differential equations of time, but analog field computation permits massively parallel temporal integration of partial differential equations. In principle many different physical media - not just electronics - can be exploited to implement the basic operations of analog computing, a small number of which are sufficient to approximate a wide variety of analog computations, thus providing a basis for universal analog computation and general-purpose analog computers. The contentious issue of the computational power of analog computers is addressed best on its own terms, rather by asking it within the context of Church-Turing computation, which distorts the relevant questions and their answers.

  20. Improved 3D-QSPR analysis of the predictive octanol-air partition coefficients of hydroxylated and methoxylated polybrominated diphenyl ethers

    NASA Astrophysics Data System (ADS)

    Liu, Hongxia; Shi, Jiaqi; Liu, Hui; Wang, Zunyao

    2013-10-01

    The octanol/air partition coefficient (KOA) is a key physicochemical parameter for describing the partition of organic pollutants between air and environment organic phase. The development of appropriate method to estimate KOA is of great importance. In the present study, the steric, electrostatic, hydrophobic, hydrogen bond donor and acceptor descriptors were computed by comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). On the basis of these parameters, the statistically quantitative structure-property relationship (QSPR) models for logKOA of hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) congeners were developed using partial least-squares (PLS) analysis, of which the R2 is about 0.980, 0.952 respectively. The electrostatic field was found to be main factors governing the logKOA. The results of validation indicate the models of this study exhibit optimum stability, and thus it is feasible to predict logKOA.

  1. Experimental investigation on the soil sorption properties and hydrophobicity of polymethoxylated, polyhydroxylated diphenyl ethers and methoxylated-, hydroxylated-polychlorinated diphenyl ethers.

    PubMed

    Zhang, Xuesheng; Zeng, Xiaolan; Qin, Li; Qu, Ruijuan; Shi, Jiaqi; Wei, Zhongbo; Yang, Shaogui; Wang, Zunyao

    2015-09-01

    In the present study, twenty-six types of polymethoxylated diphenyl ethers (PMeODEs), twenty types of polyhydroxylated diphenyl ethers (PHODEs), seven types of methoxylated-polychlorinated diphenyl ethers (MeO-PCDEs) and seven types of hydroxylated-polychlorinated diphenyl ethers (HO-PCDEs) were synthesized. The logKow and logKoc values of all of the synthesized compounds were then determined using HPLC. The soil sorption properties of five types of selected substituted diphenyl ethers (DEs) were investigated. Sorption behavior studies suggested that rapid sorption played a primary role in the sorption process of the selected DEs and their sorption isotherms were fitted the Freundlich logarithmic model. For PMeODEs and PHODEs, with the increase in the number of substituents, both logKow and logKoc values exhibited linearly decreasing trends. Unlike PMeODEs and PHODEs, both logKow and logKoc values of MeO/HO-PCDEs were decreased linearly with the increasing number of chlorine atoms. The reason maybe that both methoxy and hydroxyl are hydrophilic groups, whereas the chlorine atom is hydrophobic group. Linear relationships were observed for the logKow and logKoc of all studied DEs. Moreover, the logKow of PMeODEs, PHODEs, MeO- and HO-PCDEs and their corresponding PCDEs showed good linearity.

  2. Kinetic and Spectroscopic Studies of Aerobic Copper(II)-Catalyzed Methoxylation of Arylboronic Esters and Insights into Aryl Transmetalation to Copper(II).

    PubMed

    King, Amanda E; Ryland, Bradford L; Brunold, Thomas C; Stahl, Shannon S

    2012-11-26

    We previously reported a preliminary mechanistic study of aerobic Cu(OAc)(2)-catalyzed methoxylation of 4-tolylboronic ester (King, et al. J. Am. Chem. Soc., 2009, 131, 5044-5045), which revealed that aryl transmetalation from the boronic ester to Cu(II) is the turnover-limiting step. In the present study, more-thorough kinetic and spectroscopic studies provide additional insights into transmetalation pathway and the identity of the Cu(II) catalyst resting state(s). EPR spectroscopic studies show that at least two copper(II) species are present under catalytic conditions and their relative populations vary as a function of reaction time and acidity of the arylboronic ester, and are influenced by addition of acetic acid or acetate to the reaction mixture. Analysis of kinetic data and (11)B NMR and EPR spectra under diverse reaction conditions suggests that aryl transmetalation occurs from a tetracoordinate, anionic boronate to a cationic Cu(II) species, mediated by a methoxide-bridge. PMID:23204631

  3. Terrestrial analogs of the hellespontus dunes, Mars

    USGS Publications Warehouse

    Breed, C.S.

    1977-01-01

    Geomorphic features in the Hellespontus region, Mars, were compared with dunes of the crescentic ridge type in numerous terrestrial sand seas quantitatively by dimensional analysis of dune lengths, widths, and wavelengths. Mean values for the Hellespontus dunes are close to mean values derived from measurements of all sampled terrestrial sand seas. Terrestrial analogs of form and areal distribution of the Hellespontus dunes are shown by comparison of scale ratios derived from the measurements. Dunes of similar form occur in South West Africa, in Pakistan, in the southeastern Arabian peninsula, in the Sahara, in eastern USSR and northern China, and in western North America. Terrestrial analogs closest to form and areal distribution of the Hellespontus dunes are in the Kara Kum Desert, Turkmen SSR, and in the Ala Shan (Gobi) Desert, China. ?? 1977.

  4. Terrestrial analogs of the Hellespontus dunes, Mars

    NASA Technical Reports Server (NTRS)

    Breed, C. S.

    1977-01-01

    Geomorphic features in the Hellespontus region, Mars, were compared with dunes of the crescentic ridge type in numerous terrestrial sand seas quantitatively by dimensional analysis of dune lengths, widths, and wavelengths. Mean values for the Hellespontus dunes are close to mean values derived from measurements of all sampled terrestrial sand seas. Terrestrial analogs of form and areal distribution of the Hellespontus dunes are shown by comparison of scale ratios derived from the measurements. Dunes of similar form occur in South West Africa, in Pakistan, in the southeastern Arabian peninsula, in the Sahara, in eastern USSR and northern China, and in western North America. Terrestrial analogs closest to form and areal distribution of the Hellespontus dunes are in the Kara Kum Desert, Turkmen SSR, and in the Ala Shan (Gobi) Desert, China.

  5. Reynolds analogy for the Rayleigh problem at various flow modes.

    PubMed

    Abramov, A A; Butkovskii, A V

    2016-07-01

    The Reynolds analogy and the extended Reynolds analogy for the Rayleigh problem are considered. For a viscous incompressible fluid we derive the Reynolds analogy as a function of the Prandtl number and the Eckert number. We show that for any positive Eckert number, the Reynolds analogy as a function of the Prandtl number has a maximum. For a monatomic gas in the transitional flow regime, using the direct simulation Monte Carlo method, we investigate the extended Reynolds analogy, i.e., the relation between the shear stress and the energy flux transferred to the boundary surface, at different velocities and temperatures. We find that the extended Reynolds analogy for a rarefied monatomic gas flow with the temperature of the undisturbed gas equal to the surface temperature depends weakly on time and is close to 0.5. We show that at any fixed dimensionless time the extended Reynolds analogy depends on the plate velocity and temperature and undisturbed gas temperature mainly via the Eckert number. For Eckert numbers of the order of unity or less we generalize an extended Reynolds analogy. The generalized Reynolds analogy depends mainly only on dimensionless time for all considered Eckert numbers of the order of unity or less. PMID:27575220

  6. Reynolds analogy for the Rayleigh problem at various flow modes

    NASA Astrophysics Data System (ADS)

    Abramov, A. A.; Butkovskii, A. V.

    2016-07-01

    The Reynolds analogy and the extended Reynolds analogy for the Rayleigh problem are considered. For a viscous incompressible fluid we derive the Reynolds analogy as a function of the Prandtl number and the Eckert number. We show that for any positive Eckert number, the Reynolds analogy as a function of the Prandtl number has a maximum. For a monatomic gas in the transitional flow regime, using the direct simulation Monte Carlo method, we investigate the extended Reynolds analogy, i.e., the relation between the shear stress and the energy flux transferred to the boundary surface, at different velocities and temperatures. We find that the extended Reynolds analogy for a rarefied monatomic gas flow with the temperature of the undisturbed gas equal to the surface temperature depends weakly on time and is close to 0.5. We show that at any fixed dimensionless time the extended Reynolds analogy depends on the plate velocity and temperature and undisturbed gas temperature mainly via the Eckert number. For Eckert numbers of the order of unity or less we generalize an extended Reynolds analogy. The generalized Reynolds analogy depends mainly only on dimensionless time for all considered Eckert numbers of the order of unity or less.

  7. Antarctic Space Analog Program

    NASA Technical Reports Server (NTRS)

    Palinkas, Lawrence A; Gunderson, E. K. Eric; Johnson, Jeffrey C.; Holland, Albert W.

    1998-01-01

    The primary aim of this project was to examine group dynamics and individual performance in extreme, isolated environments and identify human factors requirements for long-duration space missions using data collected in an analog environment. Specifically, we wished to determine: 1) the characteristics of social relations in small groups of individuals living and working together in extreme, isolated environments, and 2) the environmental, social and psychological determinants of performance effectiveness in such groups. These two issues were examined in six interrelated studies using data collected in small, isolated research stations in Antarctica from 1963 to the present. Results from these six studies indicated that behavior and performance on long-duration space flights is likely to be seasonal or cyclical, situational, social, and salutogenic in nature. The project responded to two NASA program emphases for FY 1997 as described in the NRA: 1) the primary emphasis of the Behavior and Performance Program on determining long-term individual and group performance responses to space, identifying critical factors affecting those responses and understanding underlying mechanisms involved in behavior and performance, and developing and using ground-based models and analogs for studying space-related behavior and performance; and 2) the emphasis of the Data Analysis Program on extended data analysis. Results from the study were used to develop recommendations for the design and development of pre-flight crew training and in-flight psychological countermeasures for long-duration manned space missions.

  8. Modes of inactivation of trichodiene synthase by a cyclopropane-containing farnesyldiphosphate analog.

    PubMed

    Hong, Young J; Tantillo, Dean J

    2009-10-01

    We describe quantum chemical calculations on the rearrangement of carbocations derived from a cyclopropane-containing analog of farnesyl diphosphate (FPP). These calculations reveal significant differences between the energetics for rearrangement of this analog and FPP itself, suggesting that the behavior of this substrate analog likely does not mirror that of the natural substrate. In addition, our results point to new mechanisms by which this FPP analog inactivates trichodiene synthase. PMID:19763318

  9. The effect of 17-methoxyl-7-hydroxy-benzene-furanchalcone on NF-κB and the inflammatory response during myocardial ischemia reperfusion injury in rats.

    PubMed

    Liang, Xingmei; Huang, Jianchun; Lin, Xing; Qin, Feizhang; Wen, Qingwei; Chen, Chunxia; Li, Yingxin; Ge, Wenyi; Huang, Renbin

    2014-01-01

    The aim of this study was to investigate the effect of 17-methoxyl-7-hydroxy-benzene-furanchalcone (MHBFC) on nuclear factor-kappa-binding (NF-κB) and the inflammatory response in rats with myocardial ischemia reperfusion injury (MI/RI). Sprague-Dawley rats were randomly divided into 7 groups, and the rat MI/RI model was established by the ligation of the left anterior descending for 30 minutes followed by ligation release for 1 hour. Areas of myocardial infarction were measured using Evans blue-2,3,5-Triphenyltetrazolium chloride (TTC) staining. Levels of malondialdehyde, glutathione peroxidase, and total superoxide dismutase were assessed. Release of interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-10 (IL-10) was measured by means of an enzyme-linked immunosorbent assay. NF-κBp65 and intercellular adhesion molecule-1 protein expression and caspase-3 and adenine nucleotide translocator-1 messenger RNA expression were evaluated by immunohistochemistry and reverse transcription polymerase chain reaction, respectively. Pretreatment with MHBFC decreased the infarction areas, the malondialdehyde, IL-1β and IL-6 levels, the expression of caspase-3, NF-κBp65, and intercellular adhesion molecule-1. Further, MHBFC increased total superoxide dismutase and glutathione peroxidase activities, the release of IL-10, and the expression of adenine nucleotide translocator-1 messenger RNA compared with the results of the model group. The experiment showed that MHBFC protected the heart against MI/RI possibly by reducing lipid peroxidation damage while inhibiting the activity of NF-κBp65 and the inflammatory response. PMID:24126566

  10. The effects of 17-methoxyl-7-hydroxy-benzene-furanchalcone on the pressure overload-induced progression of cardiac hypertrophy to cardiac failure.

    PubMed

    Huang, Jianchun; Tang, XiaoJun; Liang, Xingmei; Wen, Qingwei; Zhang, Shijun; Xuan, Feifei; Jian, Jie; Lin, Xing; Huang, Renbin

    2014-01-01

    We investigated the effects of 17-methoxyl-7-hydroxy-benzene-furanchalcone (MHBFC), which was isolated from the roots of Millettia pulchra (Benth.) Kurz var. Laxior (Dunn) Z.Wei (Papilionaceae) (MKL), on the progression of cardiac hypertrophy to failure in a rat model of abdominal aortic banding (AAB)-induced pressure overloading. Endothelial dysfunction is central to pressure overload-induced cardiac hypertrophy and failure. It would be useful to clarify whether MHBFC could prevent this dysfunction. The effects of pressure overload were assessed in male Sprague-Dawley rats 6 weeks after AAB using the progression of cardiac hypertrophy to heart failure as the endpoint. The AAB-treated rats exhibited a greater progression to heart failure and had significantly elevated blood pressure, systolic and diastolic cardiac dysfunction, and evidence of left ventricular hypertrophy (LVH). LVH was characterized by increases in the ratios of heart and left ventricular weights to body weight, increased myocyte cross-sectional areas, myocardial and perivascular fibrosis, and elevated cardiac hydroxyproline. These symptoms could be prevented by treatment with MHBFC at daily oral doses of 6 and 12 mg/kg for 6 weeks. The progression to cardiac failure, which was demonstrated by increases in relative lung and right ventricular weights, cardiac function disorders and overexpression of atrial natriuretic peptide (ANP) mRNA, could also be prevented. Furthermore, MHBFC partialy rescued the downregulated nitric oxide signaling system, whereas inhibited the upregulated endothelin signaling system, normalizing the balance between these two systems. MHBFC protected the endothelium and prevented the pressure overload-induced progression of cardiac hypertrophy to cardiac failure. PMID:24622486

  11. The Effects of 17-Methoxyl-7-Hydroxy-Benzene-Furanchalcone on the Pressure Overload-Induced Progression of Cardiac Hypertrophy to Cardiac Failure

    PubMed Central

    Liang, Xingmei; Wen, Qingwei; Zhang, Shijun; Xuan, Feifei; Jian, Jie; Lin, Xing; Huang, Renbin

    2014-01-01

    We investigated the effects of 17-methoxyl-7-hydroxy-benzene-furanchalcone (MHBFC), which was isolated from the roots of Millettia pulchra (Benth.) Kurz var. Laxior (Dunn) Z.Wei (Papilionaceae) (MKL), on the progression of cardiac hypertrophy to failure in a rat model of abdominal aortic banding (AAB)-induced pressure overloading. Endothelial dysfunction is central to pressure overload-induced cardiac hypertrophy and failure. It would be useful to clarify whether MHBFC could prevent this dysfunction. The effects of pressure overload were assessed in male Sprague–Dawley rats 6 weeks after AAB using the progression of cardiac hypertrophy to heart failure as the endpoint. The AAB-treated rats exhibited a greater progression to heart failure and had significantly elevated blood pressure, systolic and diastolic cardiac dysfunction, and evidence of left ventricular hypertrophy (LVH). LVH was characterized by increases in the ratios of heart and left ventricular weights to body weight, increased myocyte cross-sectional areas, myocardial and perivascular fibrosis, and elevated cardiac hydroxyproline. These symptoms could be prevented by treatment with MHBFC at daily oral doses of 6 and 12 mg/kg for 6 weeks. The progression to cardiac failure, which was demonstrated by increases in relative lung and right ventricular weights, cardiac function disorders and overexpression of atrial natriuretic peptide (ANP) mRNA, could also be prevented. Furthermore, MHBFC partialy rescued the downregulated nitric oxide signaling system, whereas inhibited the upregulated endothelin signaling system, normalizing the balance between these two systems. MHBFC protected the endothelium and prevented the pressure overload-induced progression of cardiac hypertrophy to cardiac failure. PMID:24622486

  12. Temporal variations of polybrominated dibenzo-p-dioxin and methoxylated diphenyl ether concentrations in fish revealing large differences in exposure and metabolic stability.

    PubMed

    Haglund, Peter; Löfstrand, Karin; Malmvärn, Anna; Bignert, Anders; Asplund, Lillemor

    2010-04-01

    The concentrations of polybrominated dibenzo-p-dioxins (PBDDs) and polybrominated methoxylated diphenyl ethers (MeO-PBDEs) were investigated in perch (Perca fluviatilis) collected from a Baltic Sea background contaminated area between 1990 and 2005. No temporal trend was found, but large variations were observed - up to 5-fold and 160-fold differences in MeO-PBDE and PBDD concentrations, respectively - between consecutive years, suggesting that retention of these compounds, particularly the PBDDs, is limited. Examination of the congener profiles using principal component analysis (PCA) and correlation analysis indicated that MeO-PBDEs without adjacent substituents (6-MeO-BDE47) or with two adjacent substituents (2'-MeO-BDE68 and 6-MeO-BDE90) are retained more than MeO-PBDEs with three adjacent substituents (6-MeO-BDE85 and 6-MeO-BDE99) and that 1,3,6,8-tetraBDD and 1,3,7,9-tetraBDD are retained more than the other PBDDs which have vicinal hydrogen. Debromination could explain the limited retention of 6-MeO-PBDE85 and 6-MeO-BDE99 and the absence of 2-MeO-BDE123 and 6-MeO-BDE137, and cytochrome P-450 mediated oxidation could explain the limited retention of PBDDs containing vicinal hydrogen. The levels of organobromines, especially MeO-PBDEs, were found to covary with water conditions related to primary production, for example temperature, depth visibility, and inorganic nutrient concentrations, which also favor fish productivity. The results suggest natural production of MeO-PBDEs and PBDDs and imply that they fluctuate considerably over time, as do common marine toxins in fish. Thus, assessments of human and environmental risk should consider both the average and peak concentrations of these contaminants in marine biota.

  13. Mars inflatable greenhouse analog.

    PubMed

    Sadler, Philip D; Giacomelli, Gene A

    2002-01-01

    Light intensities on the Martian surface can possibly support a bioregenerative life support system (BLSS) utilizing natural sunlight for hydroponic crop production, if a suitable controlled environment can be provided. Inflatable clear membrane structures offer low mass, are more easily transported than a rigid structure, and are good candidates for providing a suitable controlled environment for crop production. Cable culture is one hydroponic growing system that can take advantage of the beneficial attributes of the inflatable structure. An analog of a Mars inflatable greenhouse can provide researchers data on issues such as crew time requirements for operation, productivity for BLSS, human factors, and much more at a reasonable cost. This is a description of one such design.

  14. Mars inflatable greenhouse analog.

    PubMed

    Sadler, Philip D; Giacomelli, Gene A

    2002-01-01

    Light intensities on the Martian surface can possibly support a bioregenerative life support system (BLSS) utilizing natural sunlight for hydroponic crop production, if a suitable controlled environment can be provided. Inflatable clear membrane structures offer low mass, are more easily transported than a rigid structure, and are good candidates for providing a suitable controlled environment for crop production. Cable culture is one hydroponic growing system that can take advantage of the beneficial attributes of the inflatable structure. An analog of a Mars inflatable greenhouse can provide researchers data on issues such as crew time requirements for operation, productivity for BLSS, human factors, and much more at a reasonable cost. This is a description of one such design. PMID:11987303

  15. Analog and digital signal processing

    NASA Astrophysics Data System (ADS)

    Baher, H.

    The techniques of signal processing in both the analog and digital domains are addressed in a fashion suitable for undergraduate courses in modern electrical engineering. The topics considered include: spectral analysis of continuous and discrete signals, analysis of continuous and discrete systems and networks using transform methods, design of analog and digital filters, digitization of analog signals, power spectrum estimation of stochastic signals, FFT algorithms, finite word-length effects in digital signal processes, linear estimation, and adaptive filtering.

  16. Neurotoxicity of artemisinin analogs in vitro.

    PubMed Central

    Wesche, D L; DeCoster, M A; Tortella, F C; Brewer, T G

    1994-01-01

    The sesquiterpene endoperoxide antimalarial agents arteether and artemether have been reported to cause neurotoxicity with a discrete distribution in the brain stems of rats and dogs after multiple doses. The nature and distribution of the brain lesions suggest a specific neuronal target, the identity of which is unknown. In order to further investigate artemisinin analog-induced neurotoxicity, we evaluated several in vitro models: fetal rat primary neuronal cultures, fetal rat secondary astrocyte cultures, and transformed neuronal cultures (rat-derived neuroblastoma NG108-15 and mouse-derived neuroblastoma Neuro-2a). Results indicate that toxicity was specific for neuronal cell types but not glial cells. Neurotoxicity, as indexed by liberation of lactate dehydrogenase and/or inhibition of radiolabelled-leucine uptake, was seen in all three neuronal culture types, implicating a common target. In vitro neurotoxicity was dose and time dependent. Acute exposure to drug results in delayed, but not immediate, manifestations of cell toxicity. Structure-activity comparisons indicate that substitutions at positions 9 and 10 and stereoisomerism at position 10 of the artemisinin backbone influence the degree of toxicity. The endoperoxide is necessary but not sufficient for toxicity. Sodium artesunate and dihydroartemisinin, a metabolite common to all artemisinin analogs currently being developed for clinical use, are the most potent of all analogs tested. These results are consistent with a specific neuronal target, but the identity of the target(s) remains unknown. PMID:7986012

  17. [Analogies and analogy research in technical biology and bionics].

    PubMed

    Nachtigall, Werner

    2010-01-01

    The procedural approaches of Technical Biology and Bionics are characterized, and analogy research is identified as their common basis. The actual creative aspect in bionical research lies in recognizing and exploiting technically oriented analogies underlying a specific biological prototype to indicate a specific technical application.

  18. FET comparator detects analog signal levels without loading analog device

    NASA Technical Reports Server (NTRS)

    Wallace, H. L.

    1966-01-01

    FET comparator circuit detects discrete analog computer output levels without excessively loading the output amplifier of the computer. An FET common source amplifier is coupled by a differential amplifier to a bistable transistor flip-flop. This circuit provides a digital output for analog voltages above or below a predetermined level.

  19. Drawing Analogies in Environmental Education

    ERIC Educational Resources Information Center

    Affifi, Ramsey

    2014-01-01

    Reconsidering the origin, process, and outcomes of analogy-making suggests practices for environmental educators who strive to disengage humans from the isolating illusions of dichotomizing frameworks. We can view analogies as outcomes of developmental processes within which human subjectivity is but an element, threading our sense of self back…

  20. Natural analog studies: Licensing perspective

    SciTech Connect

    Bradbury, J.W.

    1995-09-01

    This report describes the licensing perspective of the term {open_quotes}natural analog studies{close_quotes} as used in CFR Part 60. It describes the misunderstandings related to its definition which has become evident during discussions at the U.S Nuclear Regulatory Commission meetings and tries to clarify the appropriate applications of natural analog studies to aspects of repository site characterization.

  1. Levels of brominated flame retardants and methoxylated polybrominated diphenyl ethers in eggs of white-tailed sea eagles breeding in different regions of Sweden.

    PubMed

    Nordlöf, Ulrika; Helander, Björn; Bignert, Anders; Asplund, Lillemor

    2010-12-01

    Forty-four unhatched eggs from white-tailed sea eagle (Haliaeetus albicilla), collected in four regions in Sweden in 1992-2005, were analysed for contents of polybrominated diphenyl ethers (PBDEs), polybrominated biphenyl (PBB), hexabromocyclododecane (HBCD) and naturally occurring methoxylated polybrominated diphenyl ethers (MeO-PBDEs). Two freshwater areas-Lapland in the arctic zone (LAP) and inland lakes in central and southern Sweden (INL), and two brackish marine areas in the Baltic Sea-the south Bothnian Sea (SB) and the Baltic Proper (BP)-were chosen for comparison of the concentrations and congener distributions in white-tailed sea eagles with different diet and migratory patterns. The geometric mean (GM) concentrations (ng/g lipid weight (l.w.)) of ∑(5)PBDE (BDE-47, -99, -100, -153, and -154) were 720 (LAP), 1500 (INL), 4 100 (SB) and 4 300 (BP), whereas BDE-209 was not detectable in any of the samples. The GM concentrations for HBCD content in LAP, INL, SB and BP were 60, 90, 150 and 140ng/g l.w., respectively, whereas the corresponding values for BB-153 were 20, 30, 100 and 120ng/g l.w. In general, the eggs from all four regions demonstrated similar patterns of PBDE congeners, with concentrations in descending order of BDE-47, -100, -99, -153 and -154. The ∑(3)-MeO-BDEs (6-MeO-BDE47, 2'-MeO-BDE68, 5-Cl-6-MeO-BDE47) for these same regions (as above) were 80, 40, 340 and 240ng/g l.w., respectively. ∑(3)-MeO-BDEs for LAP and INL (freshwaters) were significantly different, whereas those for SB and BP were not. The presence of MeO-PBDEs in all of the inland samples indicates that there is an as-yet-unidentified source of these compounds in the freshwater ecosystem. Between the two more contaminated subpopulations from the Baltic Sea coast, SB showed significantly lower productivity than BP, but no correlation was found between productivity and PBDE, PBB and HBCD at the concentrations found in this study.

  2. New tetrahydroimidazo[4,5,1-jk][1,4]-benzodiazepin-2(1H)-one and -thione derivatives are potent inhibitors of human immunodeficiency virus type 1 replication and are synergistic with 2',3'-dideoxynucleoside analogs.

    PubMed Central

    Pauwels, R; Andries, K; Debyser, Z; Kukla, M J; Schols, D; Breslin, H J; Woestenborghs, R; Desmyter, J; Janssen, M A; De Clercq, E

    1994-01-01

    Tetrahydro-imidazo[4,5,1-jk][1,4]-benzodiazepin-2(1H)-one and -thione (TIBO) derivatives were shown to specifically block human immunodeficiency virus type 1 (HIV-1) replication through a unique interaction with the HIV-1 reverse transcriptase (RT). Through further modification of the lead compounds and structure-activity relationship analysis several new TIBO derivatives that show high potency, selectivity, and specificity against HIV-1 have been obtained. A new TIBO derivative, R86183, inhibits the replication of HIV-1, but not HIV-2, in a variety of CD4+ T-cell lines and peripheral blood lymphocytes, at a concentration of 0.3 to 30 nM, which is at least 4 orders of magnitude lower than the 50% cytotoxic concentration. Whereas an HIV-1 strain containing the Leu-100-->Ile mutation in the RT gene is about 400-fold less susceptible, R86183 still inhibits the replication of an HIV-1 strain containing the Tyr-181-->Cys RT mutation by 50% at a concentration of 130 nM. R86183 inhibits the poly(C).oligo(dG)12-18-directed HIV-1 RT reaction by 50% at a concentration of 57 nM. The antiviral activity of 22 TIBO derivatives in cell culture correlated well with their activity against HIV-1 RT. No such correlation was found for their cytotoxicity. The combination of R86183 with either zidovudine or didanosine resulted in a synergistic inhibition of HIV-1 (strain IIIB) replication. Combination of R86183 with the protease inhibitor Ro31-8959 was found to be additive. Also described is a dilution protocol circumventing overestimation and underestimation of antiviral activity due to adherence to plastic surfaces. Images PMID:7535037

  3. Sulfonimidamide analogs of oncolytic sulfonylureas.

    PubMed

    Toth, J E; Grindey, G B; Ehlhardt, W J; Ray, J E; Boder, G B; Bewley, J R; Klingerman, K K; Gates, S B; Rinzel, S M; Schultz, R M; Weir, L C; Worzalla, J F

    1997-03-14

    A series of sulfonimidamide analogs of the oncolytic diarylsulfonylureas was synthesized and evaluated for (1) in vitro cytotoxicity against CEM cells, (2) in vivo antitumor activity against subaxillary implanted 6C3HED lymphosarcoma, and (3) metabolic breakdown to the o-sulfate of p-chloroaniline. The separated enantiomers of one sulfonimidamide analog displayed very different activities in the in vivo screening model. In general, several analogs demonstrated excellent growth inhibitory activity in the 6C3HED model when dosed orally or intraperitoneally. A correlative structure-activity relationship to the oncolytic sulfonylureas was not apparent.

  4. Evaluating countermeasures in spaceflight analogs.

    PubMed

    Ploutz-Snyder, Lori

    2016-04-15

    Countermeasures are defined as solutions to prevent the undesirable physiologic outcomes associated with spaceflight. Spaceflight analogs provide a valuable opportunity for the evaluation of countermeasures because they allow for the evaluation of more subjects, more experimental control, and are considerably less expensive than actual spaceflight. The various human analogs have differing strengths and weaknesses with respect to the development and evaluation of countermeasures. The human analogs are briefly reviewed with a focus on their suitability for countermeasure evaluation. Bed rest is the most commonly used analog for evaluating countermeasures. While countermeasures are typically developed to target one or maybe two particular physiologic issues, it is increasingly important to evaluate all of the organ systems to discern whether they might be unintended consequences on nontargeted tissues. In preparation for Mars exploration it will be necessary to fully integrate countermeasures to protect all organ systems. The synergistic and antagonistic effects of multiple countermeasures needs to be the focus of future work. PMID:26662054

  5. Introduction to Analog Field Testing

    NASA Video Gallery

    NASA tests systems and operational concepts in analog environments, which include locations underwater, in the arctic, on terrestrial impact craters, in the desert, and on the International Space S...

  6. Flight Analogs (Bed Rest Research)

    NASA Video Gallery

    Flight Analogs / Bed Rest Research Projects provide NASA with a ground based research platform to complement space research. By mimicking the conditions of weightlessness in the human body here on ...

  7. The Robustness of Acoustic Analogies

    NASA Technical Reports Server (NTRS)

    Freund, J. B.; Lele, S. K.; Wei, M.

    2004-01-01

    Acoustic analogies for the prediction of flow noise are exact rearrangements of the flow equations N(right arrow q) = 0 into a nominal sound source S(right arrow q) and sound propagation operator L such that L(right arrow q) = S(right arrow q). In practice, the sound source is typically modeled and the propagation operator inverted to make predictions. Since the rearrangement is exact, any sufficiently accurate model of the source will yield the correct sound, so other factors must determine the merits of any particular formulation. Using data from a two-dimensional mixing layer direct numerical simulation (DNS), we evaluate the robustness of two analogy formulations to different errors intentionally introduced into the source. The motivation is that since S can not be perfectly modeled, analogies that are less sensitive to errors in S are preferable. Our assessment is made within the framework of Goldstein's generalized acoustic analogy, in which different choices of a base flow used in constructing L give different sources S and thus different analogies. A uniform base flow yields a Lighthill-like analogy, which we evaluate against a formulation in which the base flow is the actual mean flow of the DNS. The more complex mean flow formulation is found to be significantly more robust to errors in the energetic turbulent fluctuations, but its advantage is less pronounced when errors are made in the smaller scales.

  8. Soil-to-plant transfer factors of radioactive Ca, Sm and Pd isotopes: critical assessment of the use of analogies to derive best-estimates from existing non-specific data.

    PubMed

    Henner, Pascale; Hurtevent, Pierre; Thiry, Yves

    2014-10-01

    (45)Ca, (151)Sm and (107)Pd are three radionuclides present in low to intermediate in activity radioactive wastes for which no soil-to-plant Transfer Factors (TF) values are available to be used in biosphere models for Ecological Risk Assessment. In the absence of specific radioecological studies, this work reviews and analyzes the existing literature for stable isotopes of Pd, Sm and Ca in order to derive best estimates for TF values that could be used as Transfer Factors. Alternative methods of extrapolation are also critically assessed. The values have been classified according to climatic zone, plant class and soil type for each element. The overall geometric mean TF values (for all plants and conditions) was calculated as 8.4E-02 for Pd, for which the value of radioRu in TRS-472 is also available. The mean TF for Sm was 4.2E-04. This value was lower than the TF values for radioactive Ce that are proposed as alternative values for Sm in TRS-472. The former may be relevant for long term assessments and the latter could possibly used to describe the short term (151)Sm post-release behaviour. The mean value for Ca is 2.3E-01 but varies considerably among plants of a given class due to the variety of plant Ca uptake behaviors. Alternatively, to limit this variability, Ca data content for dry plant matter, as analyzed using the phylogenetic method, could be used to derive TF values if the conservation of isotopic ratio of (45)Ca to stable Ca in soils and in plants hypothesis is taken into account. The TF for Ca in sub-tropical zones is 10-fold lower than in temperate zones. There is a lot of data available about exchangeable Ca in soil, which mean that we could calculate an available TF. The analysis shows that Ca bioavailability is also a key factor within transfer.

  9. Soil-to-plant transfer factors of radioactive Ca, Sm and Pd isotopes: critical assessment of the use of analogies to derive best-estimates from existing non-specific data.

    PubMed

    Henner, Pascale; Hurtevent, Pierre; Thiry, Yves

    2014-10-01

    (45)Ca, (151)Sm and (107)Pd are three radionuclides present in low to intermediate in activity radioactive wastes for which no soil-to-plant Transfer Factors (TF) values are available to be used in biosphere models for Ecological Risk Assessment. In the absence of specific radioecological studies, this work reviews and analyzes the existing literature for stable isotopes of Pd, Sm and Ca in order to derive best estimates for TF values that could be used as Transfer Factors. Alternative methods of extrapolation are also critically assessed. The values have been classified according to climatic zone, plant class and soil type for each element. The overall geometric mean TF values (for all plants and conditions) was calculated as 8.4E-02 for Pd, for which the value of radioRu in TRS-472 is also available. The mean TF for Sm was 4.2E-04. This value was lower than the TF values for radioactive Ce that are proposed as alternative values for Sm in TRS-472. The former may be relevant for long term assessments and the latter could possibly used to describe the short term (151)Sm post-release behaviour. The mean value for Ca is 2.3E-01 but varies considerably among plants of a given class due to the variety of plant Ca uptake behaviors. Alternatively, to limit this variability, Ca data content for dry plant matter, as analyzed using the phylogenetic method, could be used to derive TF values if the conservation of isotopic ratio of (45)Ca to stable Ca in soils and in plants hypothesis is taken into account. The TF for Ca in sub-tropical zones is 10-fold lower than in temperate zones. There is a lot of data available about exchangeable Ca in soil, which mean that we could calculate an available TF. The analysis shows that Ca bioavailability is also a key factor within transfer. PMID:24956582

  10. Polymorphism of ceramide 3. Part 2: a vibrational spectroscopic and X-ray powder diffraction investigation of N-octadecanoyl phytosphingosine and the analogous specifically deuterated d(35) derivative.

    PubMed

    Raudenkolb, Steve; Wartewig, Siegfried; Neubert, Reinhard H H

    2003-07-01

    In order to characterize the arrangements of the hydrocarbon chains of ceramide 3, the thermotropic phase behaviour of the ceramides N-octadecanoylphytosphingosine (CER3) and its chain deuterated derivative N-(d(35)-octadecanoyl)phytosphingosine (d(35)CER3) was studied by means of X-ray powder diffraction, FT-IR and Raman spectroscopy. CER3 and d(35)CER3 exhibit an identical thermotropic polymorphism involving three different crystalline phases. The selective deuteration of the fatty acid chain enables to distinguish the sphingoid part from the fatty acid part by means of FT-IR and Raman spectroscopy. It could be shown that both hydrocarbon chains are arranged in different subcells. Temperature dependent Raman measurements elucidate simultaneously the changes in the trans/gauche ratios and the packing of both the hydrocarbon chains of the fatty acid and of the sphingoid part. The phase behaviour of CER3 and d(35)CER3, both dry and hydrated, was investigated. PMID:12818735

  11. Linearity optimization in a class of analog phase modulators

    NASA Technical Reports Server (NTRS)

    Hearn, C. P.

    1985-01-01

    This paper examines the ultimate modulating linearity attainable with a phase modulation technique based on the linear addition of quadrature phase carrier signals which have been multiplied by precisely defined nonlinear transformations of the modulating signal. Optimum gain coefficients are derived and plotted to permit implementation of analog phase modulators capable of exceptionally good linearity of phase deviations as large as 5 radians.

  12. All-optical analog comparator.

    PubMed

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-01-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical '1' or '0' by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function.

  13. Crows spontaneously exhibit analogical reasoning.

    PubMed

    Smirnova, Anna; Zorina, Zoya; Obozova, Tanya; Wasserman, Edward

    2015-01-19

    Analogical reasoning is vital to advanced cognition and behavioral adaptation. Many theorists deem analogical thinking to be uniquely human and to be foundational to categorization, creative problem solving, and scientific discovery. Comparative psychologists have long been interested in the species generality of analogical reasoning, but they initially found it difficult to obtain empirical support for such thinking in nonhuman animals (for pioneering efforts, see [2, 3]). Researchers have since mustered considerable evidence and argument that relational matching-to-sample (RMTS) effectively captures the essence of analogy, in which the relevant logical arguments are presented visually. In RMTS, choice of test pair BB would be correct if the sample pair were AA, whereas choice of test pair EF would be correct if the sample pair were CD. Critically, no items in the correct test pair physically match items in the sample pair, thus demanding that only relational sameness or differentness is available to support accurate choice responding. Initial evidence suggested that only humans and apes can successfully learn RMTS with pairs of sample and test items; however, monkeys have subsequently done so. Here, we report that crows too exhibit relational matching behavior. Even more importantly, crows spontaneously display relational responding without ever having been trained on RMTS; they had only been trained on identity matching-to-sample (IMTS). Such robust and uninstructed relational matching behavior represents the most convincing evidence yet of analogical reasoning in a nonprimate species, as apes alone have spontaneously exhibited RMTS behavior after only IMTS training.

  14. All-optical analog comparator

    NASA Astrophysics Data System (ADS)

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-08-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical ‘1’ or ‘0’ by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function.

  15. All-optical analog comparator

    PubMed Central

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-01-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical ‘1’ or ‘0’ by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function. PMID:27550874

  16. All-optical analog comparator.

    PubMed

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Zhao, Dongliang; Zhao, Yongpeng; Wang, Yuncai

    2016-01-01

    An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical '1' or '0' by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function. PMID:27550874

  17. Crows spontaneously exhibit analogical reasoning.

    PubMed

    Smirnova, Anna; Zorina, Zoya; Obozova, Tanya; Wasserman, Edward

    2015-01-19

    Analogical reasoning is vital to advanced cognition and behavioral adaptation. Many theorists deem analogical thinking to be uniquely human and to be foundational to categorization, creative problem solving, and scientific discovery. Comparative psychologists have long been interested in the species generality of analogical reasoning, but they initially found it difficult to obtain empirical support for such thinking in nonhuman animals (for pioneering efforts, see [2, 3]). Researchers have since mustered considerable evidence and argument that relational matching-to-sample (RMTS) effectively captures the essence of analogy, in which the relevant logical arguments are presented visually. In RMTS, choice of test pair BB would be correct if the sample pair were AA, whereas choice of test pair EF would be correct if the sample pair were CD. Critically, no items in the correct test pair physically match items in the sample pair, thus demanding that only relational sameness or differentness is available to support accurate choice responding. Initial evidence suggested that only humans and apes can successfully learn RMTS with pairs of sample and test items; however, monkeys have subsequently done so. Here, we report that crows too exhibit relational matching behavior. Even more importantly, crows spontaneously display relational responding without ever having been trained on RMTS; they had only been trained on identity matching-to-sample (IMTS). Such robust and uninstructed relational matching behavior represents the most convincing evidence yet of analogical reasoning in a nonprimate species, as apes alone have spontaneously exhibited RMTS behavior after only IMTS training. PMID:25532894

  18. Are polymers suitable rock analogs?

    NASA Astrophysics Data System (ADS)

    ten Grotenhuis, Saskia M.; Piazolo, Sandra; Pakula, T.; Passchier, Cees W.; Bons, Paul D.

    2002-05-01

    To evaluate if a polymer is suitable for analog modeling, it is essential to know the rheological properties of the material. Polymers used in analog modeling exhibit a complex rheological behavior; only part of which has been taken into account in most modeling studies. The mechanical behavior is strongly dependent on strain rate and temperature, and is characterized by specific dependencies of the storage and loss moduli, related to the elasticity and viscosity, on the deformation rate (frequency). We have measured the storage and loss moduli at a broad range of strain rates and strains, using an oscillatory parallel-disk rheometer. Investigated materials are polydimethylsiloxane (PDMS), mixtures of PDMS and BaSO 4 (filler), Rhodorsil Gomme and mixtures of Rhodorsil Gomme and plastilina, all commonly used in analog experiments. Our measurements show that the rheological properties of mixtures of plastilina and Rhodorsil Gomme depend on its deformation history. Therefore, these mixtures are problematic for analog modeling. For mixtures of PDMS and BaSO 4, the significance of the elastic component increases with increasing filler content, and accordingly, these mixtures have a limited application for modeling of viscous deformation. Pure PDMS and Rhodorsil Gomme exhibit Newtonian flow behavior at strain rates commonly used in analog modeling.

  19. Resonance Enhanced Multi-Photon Ionization and Uv-Uv Hole-Burning Spectroscopic Studies of Jet-Cooled Acetanilide Derivatives

    NASA Astrophysics Data System (ADS)

    Moon, Ceol Joo; Min, Ahreum; Ahn, Ahreum; Lee, Seung Jun; Choi, Myong Yong; Kim, Seong Keun

    2013-06-01

    Conformational investigations and photochemistry of jet-cooled methacetine (MA) and phenacetine (PA) using one color resonant two-photon ionization (REMPI), UV-UV hole-burning and IR-dip spectroscopy are presented. MA and PA are derivatives of acetanilide, substituted by methoxyl, ethoxyl group in the para position of acetanilide, respectively. Moreover, we have investigated conformational information of the acetanilide derivatives (AAP, MA and PA)-water. In this work, we will present and discuss the solvent effects of the hydroxyl group of acetanilide derivatives in the excited state.

  20. Methanogenic degradation of lignin-derived monoaromatic compounds by microbial enrichments from rice paddy field soil

    PubMed Central

    Kato, Souichiro; Chino, Kanako; Kamimura, Naofumi; Masai, Eiji; Yumoto, Isao; Kamagata, Yoichi

    2015-01-01

    Anaerobic degradation of lignin-derived aromatics is an important metabolism for carbon and nutrient cycles in soil environments. Although there are some studies on degradation of lignin-derived aromatics by nitrate- and sulfate-reducing bacteria, knowledge on their degradation under methanogenic conditions are quite limited. In this study, methanogenic microbial communities were enriched from rice paddy field soil with lignin-derived methoxylated monoaromatics (vanillate and syringate) and their degradation intermediates (protocatechuate, catechol, and gallate) as the sole carbon and energy sources. Archaeal community analysis disclosed that both aceticlastic (Methanosarcina sp.) and hydrogenotrophic (Methanoculleus sp. and Methanocella sp.) methanogens dominated in all of the enrichments. Bacterial community analysis revealed the dominance of acetogenic bacteria (Sporomusa spp.) only in the enrichments on the methoxylated aromatics, suggesting that Sporomusa spp. initially convert vanillate and syringate into protocatechuate and gallate, respectively, with acetogenesis via O-demethylation. As the putative ring-cleavage microbes, bacteria within the phylum Firmicutes were dominantly detected from all of the enrichments, while the dominant phylotypes were not identical between enrichments on vanillate/protocatechuate/catechol (family Peptococcaceae bacteria) and on syringate/gallate (family Ruminococcaceae bacteria). This study demonstrates the importance of cooperation among acetogens, ring-cleaving fermenters/syntrophs and aceticlastic/hydrogenotrophic methanogens for degradation of lignin-derived aromatics under methanogenic conditions. PMID:26399549

  1. Natural analogs for Yucca Mountain

    SciTech Connect

    Murphy, W.M.

    1995-11-01

    High-level radioactive waste in the US, spent fuels from commercial reactors and nuclear materials generated by defense activities, will remain potentially hazardous for thousands of years. Demonstrable long-term stability of certain geologic and geochemical systems motivates and sustains the concept that high-level waste can be safely isolated in geologic repositories for requisite periods of time. Each geologic repository is unique in its properties and performance with reguard to isolation of nuclear wastes. Studies of processes analogous to waste-form alteration and radioelement transport in environments analogous to Yucca Mountain are being conducted at two sites, described in this article to illustrate uses of natural analog data: the Nopal I uranium deposit in the Sierra Pena Blanca, Mexico, and the Akrotiri archaeological site on the island of Santorini, Greece.

  2. Test Wiseness and Analogy Test Performance

    ERIC Educational Resources Information Center

    Moore, James C.

    1971-01-01

    Subjects received self instruction on how to approach analogy questions. Instruction was directed toward knowledge of the general format of analogy questions in standarized tests and the 15 types of relationships commonly asked for in analogy questions. An analogies post-test showed a significant effect for the group. (Author)

  3. Analogies in Science and Science Teaching

    ERIC Educational Resources Information Center

    Brown, Simon; Salter, Susan

    2010-01-01

    Analogies are often used in science, but students may not appreciate their significance, and so the analogies can be misunderstood or discounted. For this reason, educationalists often express concern about the use of analogies in teaching. Given the important place of analogies in the discourse of science, it is necessary that students are…

  4. Multilateral Collaborations in Analog Research

    NASA Technical Reports Server (NTRS)

    Cromwell, R. l.

    2016-01-01

    International collaborations in studies utilizing ground-based space flight analogs are an effective means for answering research questions common to participating agencies. These collaborations bring together worldwide experts to solve important space research questions. By collaborating unnecessary duplication of science is reduced, and the efficiency of analog use is improved. These studies also share resources among agencies for cost effective solutions to study implementation. Recently, NASA has engaged in collaborations with international partners at a variety of analog sites. The NASA Human Exploration Research Analog (HERA) is currently hosting investigator studies from NASA and from the German Space Agency (DLR). These isolation studies will answer questions in the areas of team cohesion, sleep and circadian rhythms, and neurobehavioral correlates to function. Planning for the next HERA campaign is underway as proposal selections are being made from the International Life Sciences Research Announcement (ILSRA). Studies selected from the ILSRA will be conducted across 4 HERA missions in 2017. NASA is planning collaborative studies with DLR at the :envihab facility in Cologne, Germany. Investigations were recently selected to study the effects of 0.5% CO2 exposure over 30 days of bed rest. These studies will help to determine the fidelity of this ground-based analog for studying the visual impairment intracranial pressure syndrome. NASA is also planning a multilateral collaboration at :envihab with DLR and the European Space Agency (ESA) to examine artificial gravity as a countermeasure to mitigate the effects of 60 days of bed rest. NASA is also considering collaborations with the Russian Institute for Biomedical Problems (IBMP) in studies that will utilize their Ground-based Experimental Facility (NEK). The NEK is comprised of 4 interconnected modules and a Martian surface simulator. This isolation analog can support 3 -10 crew members for long duration

  5. Terrestrial analogs for space exploration habitation systems

    NASA Technical Reports Server (NTRS)

    Campbell, Paul D.; Brown, Jeri W.

    1992-01-01

    The Space Exploration Initiative (SEI) can use early earth-based analogs to simulate many aspects of space flight missions and system operation. These analogs can thus provide information supporting future missions to the moon and to Mars. A study was performed to investigate the potential of terrestrial analogs in simulating human space exploration missions. The study resulted in preliminary requirements and concepts for analog habitation systems, and further study in this area is necessary for SEI terrestrial analog development.

  6. A Functional-Analytic Model of Analogy Using the Relational Evaluation Procedure

    ERIC Educational Resources Information Center

    Stewart, Ian; Barnes-Holmes, Dermot; Roche, Bryan

    2004-01-01

    Analogical reasoning is conceptualized by Relational Frame Theory as responding in accordance with an equivalence relation between equivalence or other types of derived stimulus relations. The purpose of this study was to provide an empirical demonstration of analogy using the Relational Evaluation Procedure (REP), a recently developed technique…

  7. Infrared spectra of lunar soil analogs. [spectral reflectance of minerals

    NASA Technical Reports Server (NTRS)

    Aronson, J. R.

    1977-01-01

    The infrared spectra of analogs of lunar soils were investigated to further the development of methodology for interpretation of remotely measured infrared spectra of the lunar surface. The optical constants of dunite, bytownite, augite, ilmenite, and a mare glass analog were obtained. The infrared emittance spectra of powdered minerals were measured and compared with spectra calculated by the reflectance theory using a catalog of optical constants. The results indicate that the predictions of the theory closely simulate the experimental measurements if the optical constants are properly derived.

  8. Analog Input Data Acquisition Software

    NASA Technical Reports Server (NTRS)

    Arens, Ellen

    2009-01-01

    DAQ Master Software allows users to easily set up a system to monitor up to five analog input channels and save the data after acquisition. This program was written in LabVIEW 8.0, and requires the LabVIEW runtime engine 8.0 to run the executable.

  9. Geometrical Analogies in Mathematics Lessons

    ERIC Educational Resources Information Center

    Eid, Wolfram

    2007-01-01

    A typical form of thinking to approach problem solutions humanly is thinking in analogous structures. Therefore school, especially mathematical lessons should help to form and to develop corresponding heuristic abilities of the pupils. In the contribution, a summary of possibilities of mathematics lessons regarding this shall particularly be…

  10. Analogy of the Cell Project

    ERIC Educational Resources Information Center

    Science Scope, 2005

    2005-01-01

    In this project, students compare the makeup of a cell to an everyday working unit or system. They create a three-dimensional object that represents their analogy. For example, students could create a car motor or manufacturing plant. (Of course, this is totally hand-created by them, so it can be a homemade re-creation of a system, not an actual…

  11. Analog Simulation of a Laser.

    ERIC Educational Resources Information Center

    Kessler, Gary

    1982-01-01

    Presents an analog simulation of laser properties (finding time evolution of the intensity of a ruby laser pulse) which serves as the basis of a three-four hour laboratory experiment. Includes programs for solution to rate equations of a three-level laser and production of a giant pulse in a ruby laser. (Author/SK)

  12. Algicidal Activity of Stilbene Analogs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As part of our continuing search for natural product and natural product-based compounds for the control of off-flavor in catfish, a total of twenty nine stilbene analogs were synthesized and evaluated for algicidal activity against the 2-methylisoborneol (MIB)-producing cyanobacterium Oscillatoria ...

  13. Paper Analogies Enhance Biology Teaching.

    ERIC Educational Resources Information Center

    Stencel, John E.

    1997-01-01

    Describes how to use paper analogies as models to illustrate various concepts in biology, human anatomy, and physiology classes. Models include biochemical paper models, protein papergrams, a paper model of early brain development, and a 3-D paper model of a eukaryotic cell. (AIM)

  14. Mathematical Analogy and Metaphorical Insight

    ERIC Educational Resources Information Center

    Zwicky, Jan

    2010-01-01

    How are we to understand the power of certain literary metaphors? The author argues that the apprehension of good metaphors is importantly similar to the apprehension of fruitful mathematical analogies: both involve a structural realignment of vision. The author then explores consequences of this claim, drawing conceptually significant parallels…

  15. Understanding & Teaching Genetics Using Analogies

    ERIC Educational Resources Information Center

    Woody, Scott; Himelblau, Ed

    2013-01-01

    We present a collection of analogies that are intended to help students better understand the foreign and often nuanced vocabulary of the genetics curriculum. Why is it called the "wild type"? What is the difference between a locus, a gene, and an allele? What is the functional (versus a rule-based) distinction between dominant and…

  16. International Alligator Rivers Analog Project

    SciTech Connect

    Bichard, G.F.

    1988-01-01

    The Australian Nuclear Science and Technology Organization (ANSTO), the Japan Atomic Energy Research Institute, the Swedish Nuclear Power Inspectorate, the U.K. Department of the Environment, the US Nuclear Regulatory Commission (NRC), and the Power Reactor and Nuclear Fuel Development Corporation of Japan are participating under the aegis of the Nuclear Energy Agency in the International Alligator Rivers Analog Project. The project has a duration of 3 yr, starting in 1988. The project has grown out of a research program on uranium ore bodies as analogs of high-level waste (HLW) repositories undertaken by ANSTO supported by the NRC. A primary objective of the project is to develop an approach to radionuclide transport model validation that may be used by the participants to support assessments of the safety of radioactive waste repositories. The approach involves integrating mathematical and physical modeling with hydrological and geochemical field and laboratory investigations of the analog site. The Koongarra uranium ore body has been chosen as the analog site because it has a secondary ore body that has formed over the past million years as a result of leaching by groundwater flowing through fractures in the primary ore body.

  17. Electrical analog to projectile motion

    NASA Astrophysics Data System (ADS)

    Vondracek, Mark

    1998-04-01

    This article describes an electrical analog to traditional projectile problems given in high school and introductory college classes. It also discusses the importance of stressing the understanding of physical laws and principles to students, and that the physics behind a problem is more important than being able to memorize and use various equations.

  18. Analogy between Thermodynamics and Mechanics.

    ERIC Educational Resources Information Center

    Peterson, Mark A.

    1979-01-01

    Establishes and illustrates a formal analogy between the motion of a particle and the "motion" of the equilibrium state of a homogeneous system in a quasistatic process. The purpose is to show that there is a much larger set of natural coordinate transformations in thermodynamics. (GA)

  19. Bayesian Analogy with Relational Transformations

    ERIC Educational Resources Information Center

    Lu, Hongjing; Chen, Dawn; Holyoak, Keith J.

    2012-01-01

    How can humans acquire relational representations that enable analogical inference and other forms of high-level reasoning? Using comparative relations as a model domain, we explore the possibility that bottom-up learning mechanisms applied to objects coded as feature vectors can yield representations of relations sufficient to solve analogy…

  20. Inhibition of glucuronokinase by substrate analogs.

    PubMed

    Gillard, D F; Dickinson, D B

    1978-11-01

    Glucuronokinase from Lilium longiflorum pollen was purified 30- to 40- fold on a blue dextran-Sepharose column. Substrate analogs were tested for inhibitory effects, and nucleotide substrate specificity of the enzyme was determined. Nine nucleotides were tested, and all were inhibitory when the substrate was ATP. ADP was competitive with ATP and had a K(i) value of 0.23 mm. None of the other nucleotide triphosphates could effectively substitute for ATP as a nucleotide substrate. Ten mm dATP and ITP reacted only 3% as rapidly as 10 mm ATP, while the rates for 10 mm GTP, CTP, UTP, and TTP were less than 1%. The glucuronic acid analogs, methyl alpha-glucuronoside, methyl beta-glucuronoside, beta-glucuronic acid-1-phosphate, and 4-O-methylglucuronic acid were tested as possible enzyme inhibitors. The three methyl derivatives showed little or no inhibition. The beta-glucuronic acid-1-phosphate was inhibitory, with 50% inhibition obtained at 1 to 3 mm depending on the concentration of the glucuronic acid. It is concluded that the glucuronic acid-binding site on the enzyme is highly selective.

  1. ANALOG: a program for estimating paleoclimate parameters using the method of modern analogs

    USGS Publications Warehouse

    Schweitzer, Peter N.

    1994-01-01

    Beginning in the 1970s with CLIMAP, paleoclimatologists have been trying to derive quantitative estimates of climatic parameters from the sedimentary record. In general the procedure is to observe the modern distribution of some component of surface sediment that depends on climate, find an empirical relationship between climate and the character of sediments, then extrapolate past climate by studying older sediments in the same way. Initially the empirical relationship between climate and components of the sediment was determined using a multiple regression technique (Imbrie and Kipp, 1971). In these studies sea-floor sediments were examined to determine the percentage of various species of planktonic foraminifera present in them. Supposing that the distribution of foraminiferal assemblages depended strongly on the extremes of annual sea-surface temperature (SST), the foraminiferal assemblages (refined through use of varimax factor analysis) were regressed against the average SST during the coolest and warmest months of the year. The result was a set of transfer functions, equations that could be used to estimate cool and warm SST from the faunal composition of a sediment sample. Assuming that the ecological preference of the species had remained constant throughout the last several hundred thousand years, these transfer functions could be used to estimate SSTs during much of the late Pleistocene. Hutson (1980) and Overpeck, Webb, and Prentice (1985) proposed an alternative approach to estimating paleoclimatic parameters. Their 'method of modern analogs' revolved not around the existence of a few climatically-sensitive faunal assemblages but rather on the expectation that similar climatic regimes should foster similar faunal and floral assemblages. From a large pool of modern samples, those few are selected whose faunal compositions are most similar to a given fossil sample. Paleoclimate estimates are derived using the climatic character of only the most similar

  2. Synthesis and biological activity of Wuweizisu C and analogs.

    PubMed

    Chang, J B; Wang, Q; Li, Y F

    2009-01-01

    Lignans are widely distributed in nature. The earliest recorded medicinal use of lignans dated back to over 1000 years ago. Lignan-rich plant products were also active ingredients in Chinese and Japanese folk medicines for the treatment of various diseases. The dried root and stem of this plant are listed in the Chinese pharmacopoeia for the treatment of rheumatoid arthritis, gastric, duodenal ulcers and many other diseases. This review highlights synthetic strategies for the Wuweizisu C analogs and the important pharmacological activities as well as therapeutic findings related to the treatment of HBV and other diseases. Notably a significant and ongoing project on Wuweizisu C and its analogs has led to the discovery and development of two potent derivatives alpha-DDB and BICYCLOL which are currently in clinical trials against HBV, especially in lowering elevated SGPT levels. Further design, synthesis, and evaluation of Wuweizisu C analogs are discussed.

  3. Analog to digital converter for two-dimensional radiant energy array computers

    NASA Technical Reports Server (NTRS)

    Shaefer, D. H.; Strong, J. P., III (Inventor)

    1977-01-01

    The analog to digital converter stage derives a bit array of digital radiant energy signals representative of the amplitudes of an input radiant energy analog signal array and derives an output radiant energy analog signal array to serve as an input to succeeding stages. The converter stage includes a digital radiant energy array device which contains radiant energy array positions so that the analog array is less than a predetermined threshold level. A scaling device amplifies the radiant signal levels of the input array and the digital array so that the radiant energy signal level carried by the digital array corresponds to the threshold level. An adder device adds the signals of the scaled input and digital arrays at corresponding array positions to form the output analog array.

  4. Battery hydrometer with analog output

    SciTech Connect

    Patis, B.L.

    1982-09-21

    There is disclosed a battery hydrometer for providing an analog electrical signal having a magnitude related to the specific gravity of a battery electrolyte. The hydrometer includes a source of radiation for providing a detectable beam of radiation and a piston member arranged to be submerged within the electrolyte and to intercept and modulate the beam of radiation in response to the specific gravity of the electrolyte. The piston member is suspended within the electrolyte by a spring which exerts a compressive force upon the piston member against which the electrolyte must act. The hydrometer further includes a radiation detector aligned with the radiation source for providing an analog electrical signal having a magnitude responsive to the modulated beam of radiation.

  5. Analog Nonvolatile Computer Memory Circuits

    NASA Technical Reports Server (NTRS)

    MacLeod, Todd

    2007-01-01

    In nonvolatile random-access memory (RAM) circuits of a proposed type, digital data would be stored in analog form in ferroelectric field-effect transistors (FFETs). This type of memory circuit would offer advantages over prior volatile and nonvolatile types: In a conventional complementary metal oxide/semiconductor static RAM, six transistors must be used to store one bit, and storage is volatile in that data are lost when power is turned off. In a conventional dynamic RAM, three transistors must be used to store one bit, and the stored bit must be refreshed every few milliseconds. In contrast, in a RAM according to the proposal, data would be retained when power was turned off, each memory cell would contain only two FFETs, and the cell could store multiple bits (the exact number of bits depending on the specific design). Conventional flash memory circuits afford nonvolatile storage, but they operate at reading and writing times of the order of thousands of conventional computer memory reading and writing times and, hence, are suitable for use only as off-line storage devices. In addition, flash memories cease to function after limited numbers of writing cycles. The proposed memory circuits would not be subject to either of these limitations. Prior developmental nonvolatile ferroelectric memories are limited to one bit per cell, whereas, as stated above, the proposed memories would not be so limited. The design of a memory circuit according to the proposal must reflect the fact that FFET storage is only partly nonvolatile, in that the signal stored in an FFET decays gradually over time. (Retention times of some advanced FFETs exceed ten years.) Instead of storing a single bit of data as either a positively or negatively saturated state in a ferroelectric device, each memory cell according to the proposal would store two values. The two FFETs in each cell would be denoted the storage FFET and the control FFET. The storage FFET would store an analog signal value

  6. Classical Analog to Entanglement Reversibility

    NASA Astrophysics Data System (ADS)

    Chitambar, Eric; Fortescue, Ben; Hsieh, Min-Hsiu

    2015-08-01

    In this Letter we study the problem of secrecy reversibility. This asks when two honest parties can distill secret bits from some tripartite distribution pX Y Z and transform secret bits back into pX Y Z at equal rates using local operation and public communication. This is the classical analog to the well-studied problem of reversibly concentrating and diluting entanglement in a quantum state. We identify the structure of distributions possessing reversible secrecy when one of the honest parties holds a binary distribution, and it is possible that all reversible distributions have this form. These distributions are more general than what is obtained by simply constructing a classical analog to the family of quantum states known to have reversible entanglement. An indispensable tool used in our analysis is a conditional form of the Gács-Körner common information.

  7. Thermal analog device reduces machining errors

    NASA Technical Reports Server (NTRS)

    Mcclure, E. R.

    1972-01-01

    Thermal analog devices predict thermal expansion and contraction of machine structures subjected to various heat inputs. Analog devices correct positioning of machine tools to compensate for distortion of machine frame.

  8. Simple Electronic Analog of a Josephson Junction.

    ERIC Educational Resources Information Center

    Henry, R. W.; And Others

    1981-01-01

    Demonstrates that an electronic Josephson junction analog constructed from three integrated circuits plus an external reference oscillator can exhibit many of the circuit phenomena of a real Josephson junction. Includes computer and other applications of the analog. (Author/SK)

  9. Basic Electricity--a Novel Analogy.

    ERIC Educational Resources Information Center

    Grant, Richard

    1996-01-01

    Uses the analogy of water flow to introduce concepts in basic electricity. Presents a demonstration that uses this analogy to help students grasp the relationship between current, voltage, and resistance. (JRH)

  10. Hegel, Analogy, and Extraterrestrial Life

    NASA Astrophysics Data System (ADS)

    Ross, Joseph T.

    Georg Wilhelm Friedrich Hegel rejected the possibility of life outside of the Earth, according to several scholars of extraterrestrial life. Their position is that the solar system and specifically the planet Earth is the unique place in the cosmos where life, intelligence, and rationality can be. The present study offers a very different interpretation of Hegel's statements about the place of life on Earth by suggesting that, although Hegel did not believe that there were other solar systems where rationality is present, he did in fact suggest that planets in general, not the Earth exclusively, have life and possibly also intelligent inhabitants. Analogical syllogisms are superficial, according to Hegel, insofar as they try to conclude that there is life on the Moon even though there is no evidence of water or air on that body. Similar analogical arguments for life on the Sun made by Johann Elert Bode and William Herschel were considered by Hegel to be equally superficial. Analogical arguments were also used by astronomers and philosophers to suggest that life could be found on other planets in our solar system. Hegel offers no critique of analogical arguments for life on other planets, and in fact Hegel believed that life would be found on other planets. Planets, after all, have meteorological processes and therefore are "living" according to his philosophical account, unlike the Moon, Sun, and comets. Whereas William Herschel was already finding great similarities between the Sun and the stars and had extended these similarities to the property of having planets or being themselves inhabitable worlds, Hegel rejected this analogy. The Sun and stars have some properties in common, but for Hegel one cannot conclude from these similarities to the necessity that stars have planets. Hegel's arguments against the presence of life in the solar system were not directed against other planets, but rather against the Sun and Moon, both of which he said have a different

  11. Science Teachers' Analogical Reasoning

    ERIC Educational Resources Information Center

    Mozzer, Nilmara Braga; Justi, Rosária

    2013-01-01

    Analogies can play a relevant role in students' learning. However, for the effective use of analogies, teachers should not only have a well-prepared repertoire of validated analogies, which could serve as bridges between the students' prior knowledge and the scientific knowledge they desire them to understand, but also know how to…

  12. Visual homing in analog hardware.

    PubMed

    Möller, R

    1999-10-01

    Insects of several species rely on visual landmarks for returning to important locations in their environment. The "average landmark vector model" is a parsimonious model which reproduces some aspects of the visual homing behavior of bees and ants. To gain insights in the structure and complexity of the neural apparatus that might underly the navigational capabilities of these animals, the average landmark vector model was implemented in analog hardware and used to control a mobile robot. The experiments demonstrate that the apparently complex task of visual homing might be realized by simple and mostly peripheral neural circuits in insect brains.

  13. Classical analog of quantum phase

    SciTech Connect

    Ord, G.N.

    1992-07-01

    A modified version of the Feynman relativistic chessboard model (FCM) is investigated in which the paths involved are spirals in the space-time. Portions of the paths in which the particle`s proper time is reversed are interpreted in terms of antiparticles. With this intepretation the particle-antiparticle field produced by such trajectories provides a classical analog of the phase associated with particle paths in the unmodified FCM. It is shwon that in the nonrelativistic limit the resulting kernel is the correct Dirac propagator and that particle-antiparticle symmetry is in this case responsible for quantum interference. 7 refs., 3 figs.

  14. Exploring the use of multiple analogical models when teaching and learning chemical equilibrium

    NASA Astrophysics Data System (ADS)

    Harrison, Allan G.; de Jong, Onno

    2005-12-01

    This study describes the multiple analogical models used to introduce and teach Grade 12 chemical equilibrium. We examine the teacher's reasons for using models, explain each model's development during the lessons, and analyze the understandings students derived from the models. A case study approach was used and the data were drawn from the observation of three consecutive Grade 12 lessons on chemical equilibrium, pre- and post-lesson interviews, and delayed student interviews. The key analogical models used in teaching were: the school dance; the sugar in a teacup; the pot of curry; and the busy highway. The lesson and interview data were subject to multiple, independent analyses and yielded the following outcomes: The teacher planned to use the students' prior knowledge wherever possible and he responded to student questions with stories and extended and enriched analogies. He planned to discuss where each analogy broke down but did not. The students enjoyed the teaching but built variable mental models of equilibrium and some of their analogical mappings were unreliable. A female student disliked masculine analogies, other students tended to see elements of the multiple models in isolation, and some did not recognize all the analogical mappings embedded in the teaching plan. Most students learned that equilibrium reactions are dynamic, occur in closed systems, and the forward and reverse reactions are balanced. We recommend the use of multiple analogies like these and insist that teachers always show where the analogy breaks down and carefully negotiate the conceptual outcomes.

  15. Phytotoxicity of brominated diphenyl ether-47 (BDE-47) and its hydroxylated and methoxylated analogues (6-OH-BDE-47 and 6-MeO-BDE-47) to maize (Zea mays L.).

    PubMed

    Xu, Xuehui; Huang, Honglin; Wen, Bei; Wang, Sen; Zhang, Shuzhen

    2015-03-16

    Polybrominated diphenyl ethers (PBDEs), methoxylated PBDEs (MeO-PBDEs), and hydroxylated PBDEs (OH-PBDEs) are widely found in various environmental media, which is of concern given their biological toxicity. In this study, the phytotoxicities of BDE-47, 6-MeO-BDE-47, and 6-OH-BDE-47 to maize (Zea mays L.) were investigated by an in vivo exposure experiment. Results showed that BDE-47, 6-MeO-BDE-47, and 6-OH-BDE-47 inhibited seed germination and seedling development, and elevated malondialdehyde (MDA), carbonyl groups, and phosphorylated histone H2AX levels in maize roots, suggesting the inducement of lipid peroxidation, protein carbonylation, and DNA damage to maize. Exposure to BDE-47, 6-MeO-BDE-47, and 6-OH-BDE-47 caused the overproduction of H2O2, O2(•-), and •OH, and elevated the activities of antioxidant enzymes in the roots. In addition, 6-OH-BDE-47 caused more severe damage and reactive oxygen species (ROS) generation in maize than did BDE-47 and 6-MeO-BDE-47. These results demonstrated the phytotoxicities of BDE-47, 6-OH-BDE-47, and 6-MeO-BDE-47 to maize, and clarified that overproduction of ROS was the key mechanism leading to toxicity. This study offers useful information for a more comprehensive understanding of the environmental behaviors and toxicities of PBDEs, MeO-PBDEs, and OH-PBDEs. PMID:25654621

  16. Phytotoxicity of brominated diphenyl ether-47 (BDE-47) and its hydroxylated and methoxylated analogues (6-OH-BDE-47 and 6-MeO-BDE-47) to maize (Zea mays L.).

    PubMed

    Xu, Xuehui; Huang, Honglin; Wen, Bei; Wang, Sen; Zhang, Shuzhen

    2015-03-16

    Polybrominated diphenyl ethers (PBDEs), methoxylated PBDEs (MeO-PBDEs), and hydroxylated PBDEs (OH-PBDEs) are widely found in various environmental media, which is of concern given their biological toxicity. In this study, the phytotoxicities of BDE-47, 6-MeO-BDE-47, and 6-OH-BDE-47 to maize (Zea mays L.) were investigated by an in vivo exposure experiment. Results showed that BDE-47, 6-MeO-BDE-47, and 6-OH-BDE-47 inhibited seed germination and seedling development, and elevated malondialdehyde (MDA), carbonyl groups, and phosphorylated histone H2AX levels in maize roots, suggesting the inducement of lipid peroxidation, protein carbonylation, and DNA damage to maize. Exposure to BDE-47, 6-MeO-BDE-47, and 6-OH-BDE-47 caused the overproduction of H2O2, O2(•-), and •OH, and elevated the activities of antioxidant enzymes in the roots. In addition, 6-OH-BDE-47 caused more severe damage and reactive oxygen species (ROS) generation in maize than did BDE-47 and 6-MeO-BDE-47. These results demonstrated the phytotoxicities of BDE-47, 6-OH-BDE-47, and 6-MeO-BDE-47 to maize, and clarified that overproduction of ROS was the key mechanism leading to toxicity. This study offers useful information for a more comprehensive understanding of the environmental behaviors and toxicities of PBDEs, MeO-PBDEs, and OH-PBDEs.

  17. Analog computing by Brewster effect.

    PubMed

    Youssefi, Amir; Zangeneh-Nejad, Farzad; Abdollahramezani, Sajjad; Khavasi, Amin

    2016-08-01

    Optical computing has emerged as a promising candidate for real-time and parallel continuous data processing. Motivated by recent progresses in metamaterial-based analog computing [Science343, 160 (2014)SCIEAS0036-807510.1126/science.1242818], we theoretically investigate the realization of two-dimensional complex mathematical operations using rotated configurations, recently reported in [Opt. Lett.39, 1278 (2014)OPLEDP0146-959210.1364/OL.39.001278]. Breaking the reflection symmetry, such configurations could realize both even and odd Green's functions associated with spatial operators. Based on such an appealing theory and by using the Brewster effect, we demonstrate realization of a first-order differentiator. Such an efficient wave-based computation method not only circumvents the major potential drawbacks of metamaterials, but also offers the most compact possible device compared to conventional bulky lens-based optical signal and data processors.

  18. QCD analogy for quantum gravity

    NASA Astrophysics Data System (ADS)

    Holdom, Bob; Ren, Jing

    2016-06-01

    Quadratic gravity presents us with a renormalizable, asymptotically free theory of quantum gravity. When its couplings grow strong at some scale, as in QCD, then this strong scale sets the Planck mass. QCD has a gluon that does not appear in the physical spectrum. Quadratic gravity has a spin-2 ghost that we conjecture does not appear in the physical spectrum. We discuss how the QCD analogy leads to this conjecture and to the possible emergence of general relativity. Certain aspects of the QCD path integral and its measure are also similar for quadratic gravity. With the addition of the Einstein-Hilbert term, quadratic gravity has a dimensionful parameter that seems to control a quantum phase transition and the size of a mass gap in the strong phase.

  19. The Young Solar Analogs Project

    NASA Astrophysics Data System (ADS)

    Gray, Richard O.; Saken, J. M.; Corbally, C. J.; Seeds, M. F.; Morrison, S. S.

    2012-01-01

    We are carrying out a long-term project of measuring chromospheric activity and brightness variations in 31 young solar analogs (YSAs) using the Dark Sky Observatory (DSO -- Appalachian State University) 32-inch telescope and the G/M spectrograph. These YSAs are solar-type (spectral types F8 - K2) stars with ages ranging from 0.3 - 1.5 Gyr. The goal of this project is to gain better understanding of the magnetic activity of the early Sun, and especially how that activity may have impacted the development of life on the Earth. This project will also yield insights into the space environments experienced by young Earth analogs. We are currently in our 5th year of obtaining Ca II K & H chromospheric flux measurements, and are beginning to see signs of long-term activity cycles in a number of our stars. In addition, rotational modulation of the chromospheric fluxes is detectable in our data, and we have determined rotational periods for many of our stars. Short timescale increases in the K & H fluxes have been observed in a number of our stars; these events may be related to stellar flares. VATTSpec, a new moderate-resolution spectrograph on the 1.8-m Vatican Telescope in Arizona, has recently become involved with the project. This spectrograph will increase our ability to detect short-term changes in stellar activity on timescales of hours to minutes. We have been monitoring the program stars for one year in a multi-band photometric system consisting of Stromgren-v, and Johnson B, V, and R filters. We will soon add a narrow-band H-alpha filter to the system. Photometry is being carried out with a small piggy-back telescope on the 32-inch, but a robotic photometric telescope is currently being installed at DSO for this purpose. This project is supported by the National Science Foundation.

  20. Children's use of analogy during collaborative reasoning.

    PubMed

    Lin, Tzu-Jung; Anderson, Richard C; Hummel, John E; Jadallah, May; Miller, Brian W; Nguyen-Jahiel, Kim; Morris, Joshua A; Kuo, Li-Jen; Kim, Il-Hee; Wu, Xiaoying; Dong, Ting

    2012-01-01

    This microgenetic study examined social influences on children's development of analogical reasoning during peer-led small-group discussions of stories about controversial issues. A total of 277 analogies were identified among 7,215 child turns for speaking during 54 discussions from 18 discussion groups in 6 fourth-grade classrooms (N = 120; age M=10.0, SD=0.6). Use of analogy was found to spread among the children in discussion groups and occur at an accelerating rate, primarily because of the increasing use of novel analogies. Relational analogies with shared surface features triggered purely relational analogies during the next 2 speaking turns, showing a trend of relational shift. These results provide distinctive new evidence for the importance of social interaction in an aspect of cognitive development. PMID:22670717

  1. An emergent approach to analogical inference

    NASA Astrophysics Data System (ADS)

    Thibodeau, Paul H.; Flusberg, Stephen J.; Glick, Jeremy J.; Sternberg, Daniel A.

    2013-03-01

    In recent years, a growing number of researchers have proposed that analogy is a core component of human cognition. According to the dominant theoretical viewpoint, analogical reasoning requires a specific suite of cognitive machinery, including explicitly coded symbolic representations and a mapping or binding mechanism that operates over these representations. Here we offer an alternative approach: we find that analogical inference can emerge naturally and spontaneously from a relatively simple, error-driven learning mechanism without the need to posit any additional analogy-specific machinery. The results also parallel findings from the developmental literature on analogy, demonstrating a shift from an initial reliance on surface feature similarity to the use of relational similarity later in training. Variants of the model allow us to consider and rule out alternative accounts of its performance. We conclude by discussing how these findings can potentially refine our understanding of the processes that are required to perform analogical inference.

  2. Classical Analogs of a Diatomic Chain

    SciTech Connect

    Gutierrez, L.; Diaz-de-Anda, A.; Mendez-Sanchez, R. A.; Morales, A.; Flores, J.; Monsivais, G.

    2010-12-21

    Using one dimensional rods with different configurations classical analogs of quantum mechanical systems frequently used in solid state physics can be obtained. Among this analogs we have recently discussed locally periodic rods which lead to band spectra; the effect of a topological defect, and the Wannier Stark ladders. In this paper, we present an elastic analog of the diatomic chain and show how the acoustical and optical bands emerge, as well of the nature of the wave amplitudes.

  3. Real World: Analog Testing in Extreme Environments

    NASA Video Gallery

    See how NASA uses analog testing to simulate space exploration. Explore extreme environments like the Aquarius underwater laboratory in Key Largo, Florida. Find out how scientists use mathematical ...

  4. Synthesis of fluorescent nucleoside analogs as probes for 2'-deoxyribonucleoside kinases.

    PubMed

    Li, Yongfeng; Soni, Priti B; Liu, Lingfeng; Zhang, Xiao; Liotta, Dennis C; Lutz, Stefan

    2010-02-01

    We are reporting on the synthesis of fluorescent nucleoside analogs with modified sugar moieties (e.g., sugars other than ribose and 2'-deoxyribose). Four novel derivatives of the fluorescent thymidine analog 6-methyl-3-(beta-D-2'-deoxyribofuranosyl) furano-[2,3-d]pyrimidin-2-one were synthesized via Sonogashira reaction and subsequent copper-catalyzed cycloaddition. These compounds represent promising tools for studying nucleoside metabolism inside living cells, as well as for screening directed evolution libraries of 2'-deoxyribonucleoside kinases with new and improved activity for the corresponding nucleoside analogs. PMID:20060716

  5. Biosynthesis of sphinganine-analog mycotoxins.

    PubMed

    Du, L; Zhu, X; Gerber, R; Huffman, J; Lou, L; Jorgenson, J; Yu, F; Zaleta-Rivera, K; Wang, Q

    2008-06-01

    Sphinganine-analog mycotoxins (SAMT) are polyketide-derived natural products produced by a number of plant pathogenic fungi and are among the most economically important mycotoxins. The toxins are structurally similar to sphinganine, a key intermediate in the biosynthesis of ceramides and sphingolipids, and competitive inhibitors for ceramide synthase. The inhibition of ceramide and sphingolipid biosynthesis is associated with several fatal diseases in domestic animals and esophageal cancer and neural tube defects in humans. SAMT contains a highly reduced, acyclic polyketide carbon backbone, which is assembled by a single module polyketide synthase. The biosynthesis of SAMT involves a unique polyketide chain-releasing mechanism, in which a pyridoxal 5'-phosphate-dependent enzyme catalyzes the termination, offloading and elongation of the polyketide chain. This leads to the introduction of a new carbon-carbon bond and an amino group to the polyketide chain. The mechanism is fundamentally different from the thioesterase/cyclase-catalyzed polyketide chain releasing found in bacterial and other fungal polyketide biosynthesis. Genetic data suggest that the ketosynthase domain of the polyketide synthase and the chain-releasing enzyme are important for controlling the final product structure. In addition, several post-polyketide modifications have to take place before SAMT become mature toxins.

  6. Chemical modification and structure-activity relationships of pyripyropenes. 2. 1,11-Cyclic analogs.

    PubMed

    Obata, R; Sunazuka, T; Kato, Y; Tomoda, H; Harigaya, Y; Omura, S

    1996-11-01

    A series of 1,11-cyclic analogs of pyripyropene A were prepared. Replacement of the 1,11-acyl groups of pyripyropenes with 1,11-cyclic acetals effectively improved in vitro acyl CoA:cholesterol acyltransferase (ACAT) inhibitory activity. Especially noteworthy is benzylidene acetal analog 35, the most potent inhibitor (IC50 = 5.6 nM) among the derivatives prepared so far, which showed 16 times more potent inhibitory activity than pyripyropene A. PMID:8982344

  7. Memristor-MOS analog correlator for pattern recognition system.

    PubMed

    Han, Ca-Ram; Lee, Sang-Jin; Oh, Kwang-Seok; Cho, Kyoungrok

    2013-05-01

    Emergence of new materials having significant improved properties continues to influence the formulation of novel architectures and as such new developments pave the way for innovative circuits and systems such as those required in visual imaging and recognition systems. In this paper we introduce a novel approach for the design of an analog comparator suitable for pattern matching using two Memristors as part of both the stored image data as well as that of the input signal. Our proposed comparator based on Memristor-CMOS fabrication process generates a signal indicating similarity/dissimilarity between two pattern data derived from image sensor and the corresponding Memristor-based template memory. For convenience, we also present an overview of a simplified Memristor model and hence provide simulation results for comparison with that of a conventional analog CMOS comparator. PMID:23858860

  8. Memristor-MOS analog correlator for pattern recognition system.

    PubMed

    Han, Ca-Ram; Lee, Sang-Jin; Oh, Kwang-Seok; Cho, Kyoungrok

    2013-05-01

    Emergence of new materials having significant improved properties continues to influence the formulation of novel architectures and as such new developments pave the way for innovative circuits and systems such as those required in visual imaging and recognition systems. In this paper we introduce a novel approach for the design of an analog comparator suitable for pattern matching using two Memristors as part of both the stored image data as well as that of the input signal. Our proposed comparator based on Memristor-CMOS fabrication process generates a signal indicating similarity/dissimilarity between two pattern data derived from image sensor and the corresponding Memristor-based template memory. For convenience, we also present an overview of a simplified Memristor model and hence provide simulation results for comparison with that of a conventional analog CMOS comparator.

  9. Expert analogy use in a naturalistic setting

    PubMed Central

    Kretz, Donald R.; Krawczyk, Daniel C.

    2014-01-01

    The use of analogy is an important component of human cognition. The type of analogy we produce and communicate depends heavily on a number of factors, such as the setting, the level of domain expertise present, and the speaker's goal or intent. In this observational study, we recorded economics experts during scientific discussion and examined the categorical distance and structural depth of the analogies they produced. We also sought to characterize the purpose of the analogies that were generated. Our results supported previous conclusions about the infrequency of superficial similarity in subject-generated analogs, but also showed that distance and depth characteristics were more evenly balanced than in previous observational studies. This finding was likely due to the nature of the goals of the participants, as well as the broader nature of their expertise. An analysis of analogical purpose indicated that the generation of concrete source examples of more general target concepts was most prevalent. We also noted frequent instances of analogies intended to form visual images of source concepts. Other common purposes for analogies were the addition of colorful speech, inclusion (i.e., subsumption) of a target into a source concept, or differentiation between source and target concepts. We found no association between depth and either of the other two characteristics, but our findings suggest a relationship between purpose and distance; i.e., that visual imagery typically entailed an outside-domain source whereas exemplification was most frequently accomplished using within-domain analogies. Overall, we observed a rich and diverse set of spontaneously produced analogical comparisons. The high degree of expertise within the observed group along with the richly comparative nature of the economics discipline likely contributed to this analogical abundance. PMID:25505437

  10. Novel Analog For Muscle Deconditioning

    NASA Technical Reports Server (NTRS)

    Ploutz-Snyder, Lori; Ryder, Jeff; Buxton, Roxanne; Redd, Elizabeth; Scott-Pandorf, Melissa; Hackney, Kyle; Fiedler, James; Bloomberg, Jacob

    2010-01-01

    Existing models of muscle deconditioning are cumbersome and expensive (ex: bedrest). We propose a new model utilizing a weighted suit to manipulate strength, power or endurance (function) relative to body weight (BW). Methods: 20 subjects performed 7 occupational astronaut tasks while wearing a suit weighted with 0-120% of BW. Models of the full relationship between muscle function/BW and task completion time were developed using fractional polynomial regression and verified by the addition of pre- and post-flight astronaut performance data using the same tasks. Spline regression was used to identify muscle function thresholds below which task performance was impaired. Results: Thresholds of performance decline were identified for each task. Seated egress & walk (most difficult task) showed thresholds of: leg press (LP) isometric peak force/BW of 18 N/kg, LP power/BW of 18 W/kg, LP work/ BW of 79 J/kg, knee extension (KE) isokinetic/BW of 6 Nm/Kg and KE torque/BW of 1.9 Nm/kg. Conclusions: Laboratory manipulation of strength / BW has promise as an appropriate analog for spaceflight-induced loss of muscle function for predicting occupational task performance and establishing operationally relevant exercise targets.

  11. Novel Analog For Muscle Deconditioning

    NASA Technical Reports Server (NTRS)

    Ploutz-Snyder, Lori; Ryder, Jeff; Buxton, Roxanne; Redd. Elizabeth; Scott-Pandorf, Melissa; Hackney, Kyle; Fiedler, James; Ploutz-Snyder, Robert; Bloomberg, Jacob

    2011-01-01

    Existing models (such as bed rest) of muscle deconditioning are cumbersome and expensive. We propose a new model utilizing a weighted suit to manipulate strength, power, or endurance (function) relative to body weight (BW). Methods: 20 subjects performed 7 occupational astronaut tasks while wearing a suit weighted with 0-120% of BW. Models of the full relationship between muscle function/BW and task completion time were developed using fractional polynomial regression and verified by the addition of pre-and postflightastronaut performance data for the same tasks. Splineregression was used to identify muscle function thresholds below which task performance was impaired. Results: Thresholds of performance decline were identified for each task. Seated egress & walk (most difficult task) showed thresholds of leg press (LP) isometric peak force/BW of 18 N/kg, LP power/BW of 18 W/kg, LP work/BW of 79 J/kg, isokineticknee extension (KE)/BW of 6 Nm/kg, and KE torque/BW of 1.9 Nm/kg.Conclusions: Laboratory manipulation of relative strength has promise as an appropriate analog for spaceflight-induced loss of muscle function, for predicting occupational task performance and establishing operationally relevant strength thresholds.

  12. Solar System Analog; WMO Statement

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    Scientists searching for extra-solar planets have discovered the closest known analog to our own Solar System. A planet with a mass about twice that of Jupiter is in a near-circular orbit of the star HD70642, a team of astronomers from Australia, the United Kingdom, and the United States announced on 3 July at a conference in Paris on extra-solar planets.The planet measures about three-fifths the size of Jupiter, circles its star about every six years, and is in an orbit equivalent to being about halfway between Mars and Jupiter if it were located in our Solar System, according to the astronomers. The star is about 90 light years away from Earth in the constellation Puppis.Public concern about a spate of well-publicized, extreme weather events around the world this year has prompted the World Meteorological Organization to issue a statement that, as global temperatures continues to rise due to climate change, the number and intensity of extreme events might increase. The July 2 statement is based on scientific assessments by the Intergovernmental Panel on Climate Change and others, rather than on any new studies, according to Ken Davidson, director orf WMO's World Climate Program Department. The statement cites record high termperatures so far this summer in southern France and in Switzerland, an abnormally high number of tornadoes in the U.S. in May, and particularly heavy rains from tropical cyclones in Sri Lanka.

  13. The Pennies-as-Electrons Analogy

    ERIC Educational Resources Information Center

    Ashmann, Scott

    2009-01-01

    Everyday experiences familiarize students with the ways in which electricity is used, but often the underlying concepts remain a mystery. Teachers often use analogies to help students relate the flow of electrons to other common systems, but many times these analogies are incomplete and lead to more student misconceptions. However, the "pass the…

  14. Antibacterial and Antibiofilm Activities of Makaluvamine Analogs

    PubMed Central

    Nijampatnam, Bhavitavya; Nadkarni, Dwayaja H.; Wu, Hui; Velu, Sadanandan E.

    2015-01-01

    Streptococcus mutans is a key etiological agent in the formation of dental caries. The major virulence factor is its ability to form biofilms. Inhibition of S. mutans biofilms offers therapeutic prospects for the treatment and the prevention of dental caries. In this study, 14 analogs of makaluvamine, a marine alkaloid, were evaluated for their antibacterial activity against S. mutans and for their ability to inhibit S. mutans biofilm formation. All analogs contained the tricyclic pyrroloiminoquinone core of makaluvamines. The structural variations of the analogs are on the amino substituents at the 7-position of the ring and the inclusion of a tosyl group on the pyrrole ring N of the makaluvamine core. The makaluvamine analogs displayed biofilm inhibition with IC50 values ranging from 0.4 μM to 88 μM. Further, the observed bactericidal activity of the majority of the analogs was found to be consistent with the anti-biofilm activity, leading to the conclusion that the anti-biofilm activity of these analogs stems from their ability to kill S. mutans. However, three of the most potent N-tosyl analogs showed biofilm IC50 values at least an order of magnitude lower than that of bactericidal activity, indicating that the biofilm activity of these analogs is more selective and perhaps independent of bactericidal activity. PMID:25767719

  15. Piperazine-based nucleic acid analogs

    DOEpatents

    Schmidt, Jurgen; Silks, Louis A.; Michalczyk, Ryszard

    2005-01-11

    A novel nucleoside analog is disclosed which comprises a piperazine ring in the place of the ring ribose or deoxyribose sugar. Monomers utilizing a broad variety of nucleobases are disclosed, as well as oligomers comprising the monomers disclosed herein linked by a variety of linkages, including amide, phosphonamide, and sulfonamide linkages. A method of synthesizing the nucleoside analogs is also disclosed.

  16. An Analog Computer for Electronic Engineering Education

    ERIC Educational Resources Information Center

    Fitch, A. L.; Iu, H. H. C.; Lu, D. D. C.

    2011-01-01

    This paper describes a compact analog computer and proposes its use in electronic engineering teaching laboratories to develop student understanding of applications in analog electronics, electronic components, engineering mathematics, control engineering, safe laboratory and workshop practices, circuit construction, testing, and maintenance. The…

  17. A Mechanical Analogy for the Photoelectric Effect

    ERIC Educational Resources Information Center

    Kovacevic, Milan S.; Djordjevich, Alexandar

    2006-01-01

    Analogy is a potent tool in the teacher's repertoire. It has been particularly well recognized in the teaching of science. However, careful planning is required for its effective application to prevent documented drawbacks when analogies are stretched too far. Befitting the occasion of the World Year of Physics commemorating Albert Einstein's 1905…

  18. Analogical Processes and College Developmental Reading

    ERIC Educational Resources Information Center

    Paulson, Eric J.

    2014-01-01

    Although a solid body of research concerning the role of analogies in reading processes has emerged at a variety of age groups and reading proficiencies, few of those studies have focused on analogy use by readers enrolled in college developmental reading courses. The current study explores whether 232 students enrolled in mandatory (by placement…

  19. Children's Use of Analogy during Collaborative Reasoning

    ERIC Educational Resources Information Center

    Lin, Tzu-Jung; Anderson, Richard C.; Hummel, John E.; Jadallah, May; Miller, Brian W.; Nguyen-Jahiel, Kim; Morris, Joshua A.; Kuo, Li-Jen; Kim, Il-Hee; Wu, Xiaoying; Dong, Ting

    2012-01-01

    This microgenetic study examined social influences on children's development of analogical reasoning during peer-led small-group discussions of stories about controversial issues. A total of 277 analogies were identified among 7,215 child turns for speaking during 54 discussions from 18 discussion groups in 6 fourth-grade classrooms (N = 120; age…

  20. Young Children's Analogical Reasoning in Science Domains

    ERIC Educational Resources Information Center

    Haglund, Jesper; Jeppsson, Fredrik; Andersson, Johanna

    2012-01-01

    This exploratory study in a classroom setting investigates first graders' (age 7-8 years, N = 25) ability to perform analogical reasoning and create their own analogies for two irreversible natural phenomena: mixing and heat transfer. We found that the children who contributed actively to a full-class discussion were consistently successful at…

  1. The Structure of Analogical Models in Science.

    ERIC Educational Resources Information Center

    Gentner, Dedre

    Analogical models can be powerful aids to reasoning, as when light is explained in terms of water waves; or they can be misleading, as when chemical processes are thought of in terms of life processes such as putrefaction. This paper proposes a structural characterization of good science analogy using a theoretical approach in which complex…

  2. Mathematical Analogs and the Teaching of Fractions.

    ERIC Educational Resources Information Center

    Charles, Kathy; Nason, Rod; Cooper, Tom

    The literature has noted that some mathematical analogs are more effective than others for the teaching of fractions. This study aimed to evaluate the efficacy of seven mathematical analogs commonly used in the teaching of the partitive quotient fraction construct. A sample of twelve purposively selected Year Three children were presented with…

  3. 38 CFR 4.20 - Analogous ratings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Analogous ratings. 4.20 Section 4.20 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS SCHEDULE FOR RATING DISABILITIES General Policy in Rating § 4.20 Analogous ratings. When an unlisted condition is encountered...

  4. Rotanone analogs: method of preparation and use

    DOEpatents

    VanBrocklin, Henry F; O& #x27; Neil, James P; Gibbs, Andrew R; Erathodiyil, Nandanan

    2013-10-08

    The present invention provides rotenone analogs and methods of making and using them. Labeled with single photon and positron emitting isotopes, the rotenone analogs of the present invention are useful in, for example, clinical imaging applications as tracers to measure cardiac blood flow and detect regions of ischemia.

  5. Use of Analogy in Computer Language Acquisition.

    ERIC Educational Resources Information Center

    Pohl, Heidi L.; Nutter, Jane Terry

    1985-01-01

    Subjects in a study of analogic reasoning use in learning a computer language read text describing an invented LISP dialect and then solved problems and described language constructs. Five of six factors studied indicating use of analogy with a familiar computer language showed statistically significant results, supporting the hypothesis.…

  6. Synthesis and properties of salicyladehyde salicyhydrazone derivatives and their europium complexes.

    PubMed

    Meng, Defen; Liu, Fen; Lian, Xiaomei; Yang, Zehui; Guo, Dongcai

    2014-11-01

    Four novel salicyladehyde salicyhydrazone derivatives and their corresponding europium (Eu(3+)) complexes were synthesized and characterized. The formulas of the complexes were [EuL(a-d)(NO3)2](NO3) · H2O. The investigatoin of fluoresence properties of the Eu(3+) complexes showed that the salicyladehyde salicyhydrazone derivatives were efficient sensitizers for the fluoresence of Eu(3+) ions. The fluorescence intensity of the complex substituted by methyl (-CH3) was the strongest among all the Eu(3+) complexes. The exploration of the electrochemical properties of the Eu(3+) complexes showed that the introduction of electron-donating groups methyl and methoxyl (-CH3 and -OCH3) could increase the oxidation potential and the highest occupied molecular orbital (HOMO) energy level of the Eu(3+) complex; however, the results of introduction of electron-withdrawing group were just opposite.

  7. Rhenium(I) carbonyl complexes of 2,4,6-tris(2-pyridyl)-1,3,5-triazine (TPT). Rhenium(I)-promoted methoxylation of the triazine ring carbon atom in dinuclear rhenium complexes.

    PubMed

    Chen, X; Femia, F J; Babich, J W; Zubieta, J A

    2001-06-01

    2,4,6-Tris(2-pyridyl)-1,3,5-triazine (TPT) bridged dinuclear rhenium(I) tricarbonyl halide complexes with the composition (mu-TPT)[ReX(CO)(3)](2) (3, X = Cl; 4, X = Br) can be made either by one-pot reaction of TPT with 2 equiv of [ReX(CO)(5)] (X = Cl and Br) in chloroform or by reacting mononuclear [ReX(CO)(3)(TPT)] (2) (1, X = Cl; 2, X = Br) with an excess amount of [ReX(CO)(5)]. Crystal data are as follows. 1: monoclinic, P2(1)/c, a = 11.751(1) A, b = 11.376(1) A, c = 15.562(2) A, beta = 103.584(2) degrees, V = 2022.0(4) A(3), Z = 4. 2: monoclinic, P2(1)/c, a = 11.896(1) A, b = 11.396(1) A, c = 15.655(1) A, beta = 104.474(2) degrees, V = 2054.9(3) A(3), Z = 4. 3: triclinic, P1, a = 11.541(2) A, b = 12.119(2) A, c = 13.199(2) A, alpha = 80.377(2) degrees, beta = 76.204(3) degrees, gamma = 66.826(2) degrees, V = 1642.5(4) A(3), Z = 2. Crystals of 4 crystallized from acetone: triclinic, P1, a = 11.586(5) A, b = 12.144(5) A, c = 13.364(6) A, alpha = 80.599(7) degrees, beta = 76.271(8) degrees, gamma = 67.158(8) degrees, V = 1678.0(12) A(3), Z = 2. Crystals of 4' are obtained from CH(2)Cl(2)-pentane solution: monoclinic, C2/c, a = 17.555(4) A, b = 15.277(3) A, c = 13.093(3) A, beta = 111.179(3) degrees, V = 3274.0(12) A(3), Z = 4. By contrast, similar reactions in the presence of methanol yielded complexes with the composition [mu-C(3)N(3)(OMe)(py)(2)(pyH)][ReX(CO)(3)](2) (5, X = Cl; 6, X = Br). Crystal data for 5: monoclinic, C2/c, a = 26.952(2) A, b = 16.602(1) A, c = 14.641(1) A, beta = 116.147(1) degrees, V = 5880.5(8) A(3), Z = 8. 6: monoclinic, C2/c, a = 27.513(3) A, b = 16.740(2) A, c = 14.837(2) A, beta = 116.925(2) degrees, V = 6092.8(10) A(3), Z = 8. An unusual metal-induced methoxylation at the carbon atom of the triazine ring of the bridging TPT ligand was observed. The nucleophilic attack of MeO(-) on C(3) results in a tetrahedral geometry around the carbon atom. Concomitantly, the uncoordinated pyridyl ring is protonated and rotated into a perpendicular

  8. Novel epigallocatechin gallate analogs as potential anticancer agents: a patent review (2009 – present)

    PubMed Central

    Landis-Piwowar, Kristin; Chen, Di; Foldes, Robert; Chan, Tak-Hang; Dou, Qing Ping

    2013-01-01

    Introduction Over the past three years numerous patents and patent applications have been published relating to scientific advances in the use of the green tea polyphenol epigallocatechin gallate (EGCG) (the most abundant, and bioactive compound in green tea) and its analogs as anticancer agents. EGCG affects multiple molecular targets involved in cancer cell proliferation and survival; however, polyphenolic catechins, such as EGCG, generally exhibit poor oral bioavailability. Since the anticancer activity of polyphenols largely depends on their susceptibility to biotransformation reactions, numerous EGCG derivatives, analogs and prodrugs have been designed to improve the stability, bioavailability and anticancer potency of the native compound. Areas covered This review focuses on the applications of EGCG and its analogs, derivatives and prodrugs in the prevention and treatment of human cancers. A comprehensive description of patents related to EGCG and its derivatives, analogs and prodrugs and their uses as anticancer agents is included. Expert opinion EGCG targets multiple essential survival proteins and pathways in human cancer cells. Because it is unstable physiologically, numerous alterations to the EGCG molecule have been patented, either to improve the integrity of the native compound or to generate a more stable yet similarly efficacious molecule. EGCG and its derivatives, analogs and prodrugs could be developed into future drugs for chemoprevention, chemosensitization, radiosensitization and/or cancer interception. PMID:23230990

  9. An Analog Earth Climate Model

    NASA Astrophysics Data System (ADS)

    Varekamp, J. C.

    2010-12-01

    The earth climate is broadly governed by the radiative power of the sun as well as the heat retention and convective cooling of the atmosphere. I have constructed an analog earth model for an undergraduate climate class that simulates mean climate using these three parameters. The ‘earth’ is a hollow, black, bronze sphere (4 cm diameter) mounted on a thin insulated rod, and illuminated by two opposite optic fibers, with light focused on the sphere by a set of lenses. The sphere is encased in a large double-walled aluminum cylinder (34 cm diameter by 26 cm high) with separate water cooling jackets at the top, bottom, and sides. The cylinder can be filled with a gas of choice at a variety of pressures or can be run in vacuum. The exterior is cladded with insulation, and the temperature of the sphere, atmosphere and walls is monitored with thermocouples. The temperature and waterflow of the three cooling jackets can be monitored to establish the energy output of the whole system; the energy input is the energy yield of the two optic fibers. A small IR transmissive lens at the top provides the opportunity to hook up the fiber of a hyper spectrometer to monitor the emission spectrum of the black ‘earth’ sphere. A pressure gauge and gas inlet-outlet system for flushing of the cell completes it. The heat yield of the cooling water at the top is the sum of the radiative and convective components, whereas the bottom jacket only carries off the radiative heat of the sphere. Undergraduate E&ES students at Wesleyan University have run experiments with dry air, pure CO2, N2 and Ar at 1 atmosphere, and a low vacuum run was accomplished to calibrate the energy input. For each experiment, the lights are flipped on, the temperature acquisition routine is activated, and the sphere starts to warm up until an equilibrium temperature has been reached. The lights are then flipped off and the cooling sequence towards ambient is registered. The energy input is constant for a given

  10. Investigation of Celestial Solid Analogs

    NASA Technical Reports Server (NTRS)

    Sievers, A. J.

    2003-01-01

    Our far infrared studies of both hydrophobic and hydrophilic aerogel grains have demonstrated that the mm and sub-mm wave absorption produced by the fundamental two level systems (TLS) mechanism represents a more significant contribution for these open grain structures than for bulk amorphous silicate grains. We found that the region with the anomalous temperature dependence of the spectral index due to the TLS excitations can extend in a fluffy material up to 80 per cm, which is well beyond its typical upper limit for bulk glasses. Currently there is no theoretical explanation for this surprising result. The effects of reduced dimensionality on the optical properties of carbonaceous grains have been studied with a systematic investigation of carbon aerogels. This spectroscopic approach has permitted a more reliable determination of the single grain mass normalized absorption coefficient based on the experimentally determined characteristics of the fluffy material rather than on first principles calculations involving the bulk properties of the substance. Our finding is that the electrical connectivity of the material is the main factor affecting its far infrared absorption coefficient. Another one of the main constituents of the interstellar dust, amorphous ice, has been investigated in the mm-wave region both in the high (HDA) and low (LDA) density amorphous phases and as a function of impurities. We found that doping either phase with ionic (LiCl) or molecular (methanol) impurities decreases the difference in the mm-wave absorption coefficient between the HDA and LDA ice phases so that the HDA spectrum can be used as an analog for impure ice absorption in the far infrared spectral region.

  11. [Cell analogs of viral proteins].

    PubMed

    Blinov, V M; Gaĭsler, V; Krasnov, G S; Shargunov, A V; Shurdov, M A; Zverev, V V

    2014-01-01

    Horizontal transfer of genes between viruses and their hosts played an important role in the evolution of various eukaryotes including contemporary mammals as well as the pathogens themselves. Elements of viruses of various types can be found in the genome of animals. Endogenous retroviral elements composing up to 8% of human genome length not only determine its high flexibility and rapid adaptation potential. Many of virus genes such as Fv1, Lv1, Lv2 being analogues of capsid and other proteins determine effective suppression of viral replication after cell penetration by the causative agent. Introduction of these elements into genome of a wide variety of animals from fish to primates could have taken place against the background of global natural cataclysms of viral origin. Integration of retrovirus genes coding surface glycoproteins with immunosuppressing domains into genetic apparatus of animals served as an impetus to the development of viviparity and spread ofplacental mammals. Their cell analogs syncytins perform a dual function: take direct part in the formation of syncytiotrophoblast layer of placenta and ensure tolerance of immune system of mother to embryo. The acquisition of cell genes by viruses also played an important role in their evolution: various interleukins and other modulators of immune response introduced into viral genome from cell genetic apparatus became one of the most important factors of pathogenicity of a wide variety of causative agents including poxviruses, cytomegalovirus, Epstein-Barr virus and many others. Evolutionary pathways of the virus and host are thus inseparable from each other, and character of one of these directions is largely dictated by the vector of another. PMID:25051706

  12. Radioiodinated carnitine and acylcarnitine analogs as potential myocardial imaging agents

    SciTech Connect

    McConnell, D.S.

    1991-01-01

    R-carnitine is extremely important in mammalian energy metabolism. Gamma-butyrobetaine, the immediate biosynthetic precursor to R-carnitine, is synthesized in many organs. However, only liver can hydroxylate gamma-butyrobetaine to carnitine. Thus the transport of carnitine from its site of synthesis to the site of utilization is of utmost importance. Carnitine is found in highest concentration in cardiac and skeletal muscle, where it is required for the transport of fatty acids into the mitochondria. Before fatty acids are utilized as fuel for the myocyte by beta-oxidation, they are bound to carnitine as an acylcarnitine ester at the 3-hydroxyl, and transported across the micochondrial membranes. R,S-Carnitine has been shown to be taken up by myocytes. The author has begun a study on the use of carnitine derivatives as potential carriers for the site-specific delivery of radioiodine to bidning sites in the myocardium. Such agents labeled with a gamma-emitting nuclide such as iodine-123 would be useful for the noninvasive imaging of these tissues. The aim was to synthesize a variety of radiolabeled analogs of carnitine and acylcarnitine to address questions of transport, binding and availability for myocardial metabolism. These analogs consist of N-alkylated derivatives of carnitine, acylcarnitine esters as well as carnitine amides and ethers. One C-alkylated derivative showed interesting biodistribution, elevated myocardial uptake and competition with carnitine for binding in the myocardium.

  13. Fostering Multilateral Involvement in Analog Research

    NASA Technical Reports Server (NTRS)

    Cromwell, Ronita L.

    2015-01-01

    International collaboration in space flight research is an effective means for conducting investigations and utilizing limited resources to the fullest extent. Through these multilateral collaborations mutual research questions can be investigated and resources contributed by each international partner to maximize the scientific benefits to all parties. Recently the international partners embraced this approach to initiate collaborations in ground-based space flight analog environments. In 2011, the International Analog Research Working Group was established, and later named the International Human Space Flight Analog Research Coordination Group (HANA). Among the goals of this working group are to 1) establish a framework to coordinate research campaigns, as appropriate, to minimize duplication of effort and enhance synergy; 2) define what analogs are best to use for collaborative interests; and 3) facilitate interaction between discipline experts in order to have the full benefit of international expertise. To accomplish these goals, HANA is currently engaged in developing international research campaigns in ground-based analogs. Plans are being made for an international solicitation for proposals to address research of common interest to all international partners. This solicitation with identify an analog environment that will best accommodate the types of investigations requested. Once selected, studies will be integrated into a campaign and implemented at the analog site. Through these combined efforts, research beneficial to all partners will be conducted efficiently to further address human risks of space exploration.

  14. Analogies: Explanatory Tools in Web-Based Science Instruction

    ERIC Educational Resources Information Center

    Glynn, Shawn M.; Taasoobshirazi, Gita; Fowler, Shawn

    2007-01-01

    This article helps designers of Web-based science instruction construct analogies that are as effective as those used in classrooms by exemplary science teachers. First, the authors explain what analogies are, how analogies foster learning, and what form analogies should take. Second, they discuss science teachers' use of analogies. Third, they…

  15. Bioactive fused heterocycles: Nucleoside analogs with an additional ring.

    PubMed

    Jahnz-Wechmann, Zofia; Framski, Grzegorz; Januszczyk, Piotr; Boryski, Jerzy

    2015-06-01

    The following mini-review summarizes the basic literature data regarding synthesis, biological activity, structure-activity relationship, and discussion of the mechanisms of action of two major classes of nucleoside analogs with fused heterocyclic rings: (i) the ethenonucleosides and their related derivatives of the 5,9-dihydro-3-glycosyl-6-alkyl-9-oxo-5H-imidazo[1,2-a]purine type; (ii) the bicyclic nucleosides of 6-alkyl-2,3-dihydrofurano[2,3-d]-pyrimidin-2(3H)-one and 6-alkyl-2,3-dihydropyrrolo[2,3-d]-pyrimidin-2(3H,7H)-one. PMID:25576500

  16. Preparation of 2-hydroxy-5-oxoproline and analogs thereof

    DOEpatents

    Martinez, Rodolfo A.; Unkefer, Pat J.

    2001-01-01

    The compound 2-hydroxy-5-oxoproline and analogs thereof may be used to produce an increase in carbon dioxide fixation, growth, dry weight, nutritional value (proteins and amino acids), nodulation and nitrogen fixation and photosynthetically derived chemical energy when applied to plants through their roots and/or through their foliar portions. The present invention includes an essentially quantitative chemical synthesis for this compound which is performed in a single step reaction of Fremy's Salt (potassium nitrosodisulphonate) with either glutamine or 2-pyrrolidone-5-carboxylic acid. Fremy's salt (potassium nitrosodisulphonate) is available commercially, or can be readily synthesized.

  17. Programmable Analog-To-Digital Converter

    NASA Technical Reports Server (NTRS)

    Kist, Edward H., Jr.

    1993-01-01

    High-speed analog-to-digital converter with programmable voltage steps that can be changed during operation. Allows concentration of converter resolution over specific portion of waveform. Particularly useful in digitizing wind-shear radar and lidar return signals, in digital oscilloscopes, and other applications in which desirable to increase digital resolution over specific area of waveform while accepting lower resolution over rest of waveform. Effective increase in dynamic range achieved without increase in number of analog-to-digital converter bits. Enabling faster analog-to-digital conversion.

  18. Analog detection for cavity lifetime spectroscopy

    DOEpatents

    Zare, Richard N.; Harb, Charles C.; Paldus, Barbara A.; Spence, Thomas G.

    2001-05-15

    An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

  19. Analog detection for cavity lifetime spectroscopy

    DOEpatents

    Zare, Richard N.; Harb, Charles C.; Paldus, Barbara A.; Spence, Thomas G.

    2003-01-01

    An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

  20. Comparative conformational analysis of peptide T analogs

    NASA Astrophysics Data System (ADS)

    Akverdieva, Gulnare; Godjayev, Niftali; Akyuz, Sevim

    2009-01-01

    A series of peptide T analogs were investigated within the molecular mechanics framework. In order to determine the role of the aminoacid residues in spatial formation of peptide T the conformational peculiarities of the glycine-substituted analogs were investigated. The conformational profiles of some biologically tested analogs of this peptide were determined independently. The received data permit to assess the active form of this peptide. It is characterized by β-turn at the C-terminal physiologically active pentapeptide fragment of peptide molecule. The received results are important for the investigation of the structure-activity relationship and may be used at design of a rigid-molecule drug against HIV.

  1. Synthesis of a novel carbocyclic analog of bredinin.

    PubMed

    Nair, Vasu; Zhang, Fan

    2013-09-17

    The natural nucleoside antibiotic, bredinin, exhibits antiviral and other biological activities. While various nucleosides related to bredinin have been synthesized, its carbocyclic analog has remained unknown. Synthesis of this heretofore unknown analog of bredinin is described. The key precursor, (3aS,4R,6R,6aR)-6-((methoxy-methoxy)methyl)-2,2-dimethyltetrahydro-3aH-cyclopenta[d][1,3]dioxol-4-amine (5), was prepared from the commercially available compound, (1R,4S)-2-azabicyclo[2.2.1] hept-5-en-3-one (4). Our initial approach used intermediate 6, derived in three transformations from 5, for the key photolytic step to produce the desired ring-opened precursor to the target compound. This photochemical transformation was unsuccessful. However, an appropriately protected and related precursor was synthesized from 5 through the following side-chain functional group transformations: elaboration of the amino group through malonyl ester formation, oximation at the central carbon, conversion of ester to amide and catalytic reduction of the oxime group. This precursor, on treatment with triethylorthoformate and catalytic acetic acid in ethanol, underwent cyclization to produce the desired 4-carbamoyl-imidazolium-5-olate ring. Deprotection of the latter product proceeded smoothly to give the carbocyclic analog of bredinin. This target molecule exhibits antiviral activity, albeit low, against a number of RNA viruses. Further biological evaluations are in progress.

  2. Synthesis of stable aminoacyl-tRNA analogs.

    PubMed

    Chemama, Maryline; Fonvielle, Matthieu; Lecerf, Maxime; Mellal, Dénia; Fief, Hélène; Arthur, Michel; Etheve-Quelquejeu, Mélanie

    2011-03-01

    Aminoacyl-tRNAs have important roles in a variety of biological processes. Here, we describe the synthesis of stable aminoacyl-tRNA analogs containing 1,4-substituted 1,2,3-triazole rings. The procedure involves (i) copper-catalyzed cycloadditions of 3'-or 2'-azido-adenosine and alkynes, (ii) coupling between the resulting triazole-deoxyadenosine derivatives and a deoxycytidine phosphoramidite, and (iii) the enzymatic ligation of the 2'- or 3'-triazole-dinucleotides with a 22-nt RNA microhelix that mimics the acceptor arm of tRNA. Each nucleoside and nucleotide intermediate was characterized by MS spectrometry and (1)H, (31)P, and (13)C NMR spectroscopy, and the tRNA-analogs were assayed for inhibition of FemXWv, an alanyl-transferase essential for the formation of the peptidoglycan network of Gram-positive bacterial pathogens. The low IC(50) values obtained (2 to 4 µM) indicate that the five-membered triazole rings acted as an isosteres of esters and can be used for the design of stable aminoacyl-tRNA analogs.

  3. Analog Computer Laboratory with Biological Examples.

    ERIC Educational Resources Information Center

    Strebel, Donald E.

    1979-01-01

    The use of biological examples in teaching applications of the analog computer is discussed and several examples from mathematical ecology, enzyme kinetics, and tracer dynamics are described. (Author/GA)

  4. An Electrical Analog Computer for Poets

    ERIC Educational Resources Information Center

    Bruels, Mark C.

    1972-01-01

    Nonphysics majors are presented with a direct current experiment beyond Ohms law and series and parallel laws. This involves construction of an analog computer from common rheostats and student-assembled voltmeters. (Author/TS)

  5. Synthesis of sulfonate analogs of bile acids.

    PubMed

    Kihira, K; Mikami, T; Ikawa, S; Okamoto, A; Yoshii, M; Miki, S; Mosbach, E H; Hoshita, T

    1992-04-01

    Sulfonate analogs of C23 and C24 bile acids were synthesized from norcholic, norchenodeoxycholic, norursodeoxycholic, nordeoxycholic, norhyodeoxycholic, cholic, deoxycholic, hyodeoxycholic, and lithocholic acids. The principal reactions used were (1) reduction of the bile acids with NaBH4 to the corresponding bile alcohols, (2) selective tosylation of the terminal hydroxyl group, (3) iodination of the tosyl esters with NaI, and (4) treatment of the iodides with Na2SO3 to form the sulfonate analogs of the bile acids. The sulfonate analogs showed polarity similar to that of taurine-conjugated bile acids on thin-layer chromatography. The carbon 13 nuclear magnetic resonance spectral data for the sulfonate analogs were tabulated.

  6. NASA Now: Exploring Asteroids: An Analog Mission

    NASA Video Gallery

    NASA’s Extreme Environment Mission Operations, or NEEMO, project lead Bill Todd describes this analog mission and how aquanauts living and working in an undersea habitat are helping NASA prepare ...

  7. An Electronic Analog of the Diffraction Grating.

    ERIC Educational Resources Information Center

    MacLeod, A. M.

    1978-01-01

    Gives an outline description of electronic circuitry which is analogous to the optical diffraction grating or to crystals used in the Bragg reflection of X-rays or electron waves, and explains how to use it. (Author/GA)

  8. Computer Analogies: Teaching Molecular Biology and Ecology.

    ERIC Educational Resources Information Center

    Rice, Stanley; McArthur, John

    2002-01-01

    Suggests that computer science analogies can aid the understanding of gene expression, including the storage of genetic information on chromosomes. Presents a matrix of biology and computer science concepts. (DDR)

  9. The Analog (Computer) As a Physiology Adjunct.

    ERIC Educational Resources Information Center

    Stewart, Peter A.

    1979-01-01

    Defines and discusses the analog computer and its use in a physiology laboratory. Includes two examples: (1) The Respiratory Control Function and (2) CO-Two Control in the Respiratory System. Presents diagrams and mathematical models. (MA)

  10. Optical analog-to-digital converter

    DOEpatents

    Vawter, G. Allen; Raring, James; Skogen, Erik J.

    2009-07-21

    An optical analog-to-digital converter (ADC) is disclosed which converts an input optical analog signal to an output optical digital signal at a sampling rate defined by a sampling optical signal. Each bit of the digital representation is separately determined using an optical waveguide interferometer and an optical thresholding element. The interferometer uses the optical analog signal and the sampling optical signal to generate a sinusoidally-varying output signal using cross-phase-modulation (XPM) or a photocurrent generated from the optical analog signal. The sinusoidally-varying output signal is then digitized by the thresholding element, which includes a saturable absorber or at least one semiconductor optical amplifier, to form the optical digital signal which can be output either in parallel or serially.

  11. Methoxylation of Singly Bonded 1,4-1',4'-BnC60-C60Bn Dimer: Preferential Formation of 1,4-C60 Adduct with Sterically Less Demanding Addends and Stability Difference between 1,2- and 1,4-OMe(Bn)C60.

    PubMed

    He, Fa-Gui; Li, Zong-Jun; Gao, Xiang

    2016-08-01

    Methoxylation of the singly bonded 1,4-1',4'-BnC60-C60Bn dimer afforded 1,4-OMe(Bn)C60, a 1,4-C60 adduct with sterically less demanding addends, as the major adduct. The situation was different from that of direct functionalization of C60, where 1,2-OMe(Bn)C60 was obtained as the major product. The reaction was studied with in situ vis-NIR spectroscopy and computational calculations to obtain a better understanding of this unusual regioselectivity. The stability difference between 1,2- and 1,4-OMe(Bn)C60 was studied. PMID:27387300

  12. AMiBA WIDEBAND ANALOG CORRELATOR

    SciTech Connect

    Li, Chao-Te; Kubo, Derek Y.; Lin, Kai-Yang; Chen, Ming-Tang; Ho, P. T. P.; Chen, Chung-Cheng; Han, Chih-Chiang; Oshiro, Peter; Martin-Cocher, Pierre; Chang, Chia-Hao; Chang, Shu-Hao; Altamirano, Pablo; Jiang, Homin; Wilson, Warwick; Chiueh, Tzi-Dar; Lien, Chun-Hsien; Wang, Huei; Wei, Ray-Ming; Yang, Chia-Hsiang; Peterson, Jeffrey B.

    2010-06-10

    A wideband analog correlator has been constructed for the Yuan-Tseh Lee Array for Microwave Background Anisotropy. Lag correlators using analog multipliers provide large bandwidth and moderate frequency resolution. Broadband intermediate frequency distribution, back-end signal processing, and control are described. Operating conditions for optimum sensitivity and linearity are discussed. From observations, a large effective bandwidth of around 10 GHz has been shown to provide sufficient sensitivity for detecting cosmic microwave background variations.

  13. ANALOG-TO-DIGITAL DATA CONVERTER

    DOEpatents

    Rodgers, G.W.; Althouse, J.E.; Anderson, D.P.; Bussey, G.R.; Minnear, L.H.

    1960-09-01

    Electrical apparatus is described, particularly useful in telemetry work, for converting analog signals into electrical pulses and recording them. An electronic editor commands the taking of signal readings at a frequency which varies according to linearity of the analog signal being converted. Readings of information signals are recorded, along with time base readings and serial numbering, if desired, on magnetic tape and the latter may be used to operate a computer or the like. Magnetic tape data may be transferred to punched cards.

  14. Analog environments in space human factors

    NASA Technical Reports Server (NTRS)

    Connors, Mary M.

    1992-01-01

    An account is given of what has been learned from space analog environments, which mimic such significant features of space as isolation, confinement, risk, and deprivation; emphasis is placed on the especially successful environments constituted by extended submarine research, undersea habitats, and Antarctic station wintering. Attention is also given to the advantages and limitations of the use of analog environments for space human factors research, and possibilities for such research efforts' management.

  15. AMiBA Wideband Analog Correlator

    NASA Astrophysics Data System (ADS)

    Li, Chao-Te; Kubo, Derek Y.; Wilson, Warwick; Lin, Kai-Yang; Chen, Ming-Tang; Ho, P. T. P.; Chen, Chung-Cheng; Han, Chih-Chiang; Oshiro, Peter; Martin-Cocher, Pierre; Chang, Chia-Hao; Chang, Shu-Hao; Altamirano, Pablo; Jiang, Homin; Chiueh, Tzi-Dar; Lien, Chun-Hsien; Wang, Huei; Wei, Ray-Ming; Yang, Chia-Hsiang; Peterson, Jeffrey B.; Chang, Su-Wei; Huang, Yau-De; Hwang, Yuh-Jing; Kesteven, Michael; Koch, Patrick; Liu, Guo-Chin; Nishioka, Hiroaki; Umetsu, Keiichi; Wei, Tashun; Proty Wu, Jiun-Huei

    2010-06-01

    A wideband analog correlator has been constructed for the Yuan-Tseh Lee Array for Microwave Background Anisotropy. Lag correlators using analog multipliers provide large bandwidth and moderate frequency resolution. Broadband intermediate frequency distribution, back-end signal processing, and control are described. Operating conditions for optimum sensitivity and linearity are discussed. From observations, a large effective bandwidth of around 10 GHz has been shown to provide sufficient sensitivity for detecting cosmic microwave background variations.

  16. Analog hardware for learning neural networks

    NASA Technical Reports Server (NTRS)

    Eberhardt, Silvio P. (Inventor)

    1991-01-01

    This is a recurrent or feedforward analog neural network processor having a multi-level neuron array and a synaptic matrix for storing weighted analog values of synaptic connection strengths which is characterized by temporarily changing one connection strength at a time to determine its effect on system output relative to the desired target. That connection strength is then adjusted based on the effect, whereby the processor is taught the correct response to training examples connection by connection.

  17. Synthetic heparin-binding growth factor analogs

    DOEpatents

    Pena, Louis A.; Zamora, Paul; Lin, Xinhua; Glass, John D.

    2007-01-23

    The invention provides synthetic heparin-binding growth factor analogs having at least one peptide chain that binds a heparin-binding growth factor receptor, covalently bound to a hydrophobic linker, which is in turn covalently bound to a non-signaling peptide that includes a heparin-binding domain. The synthetic heparin-binding growth factor analogs are useful as soluble biologics or as surface coatings for medical devices.

  18. Analog modelling of obduction processes

    NASA Astrophysics Data System (ADS)

    Agard, P.; Zuo, X.; Funiciello, F.; Bellahsen, N.; Faccenna, C.; Savva, D.

    2012-04-01

    Obduction corresponds to one of plate tectonics oddities, whereby dense, oceanic rocks (ophiolites) are presumably 'thrust' on top of light, continental ones, as for the short-lived, almost synchronous Peri-Arabic obduction (which took place along thousands of km from Turkey to Oman in c. 5-10 Ma). Analog modelling experiments were performed to study the mechanisms of obduction initiation and test various triggering hypotheses (i.e., plate acceleration, slab hitting the 660 km discontinuity, ridge subduction; Agard et al., 2007). The experimental setup comprises (1) an upper mantle, modelled as a low-viscosity transparent Newtonian glucose syrup filling a rigid Plexiglas tank and (2) high-viscosity silicone plates (Rhodrosil Gomme with PDMS iron fillers to reproduce densities of continental or oceanic plates), located at the centre of the tank above the syrup to simulate the subducting and the overriding plates - and avoid friction on the sides of the tank. Convergence is simulated by pushing on a piston at one end of the model with velocities comparable to those of plate tectonics (i.e., in the range 1-10 cm/yr). The reference set-up includes, from one end to the other (~60 cm): (i) the piston, (ii) a continental margin containing a transition zone to the adjacent oceanic plate, (iii) a weakness zone with variable resistance and dip (W), (iv) an oceanic plate - with or without a spreading ridge, (v) a subduction zone (S) dipping away from the piston and (vi) an upper, active continental margin, below which the oceanic plate is being subducted at the start of the experiment (as is known to have been the case in Oman). Several configurations were tested and over thirty different parametric tests were performed. Special emphasis was placed on comparing different types of weakness zone (W) and the extent of mechanical coupling across them, particularly when plates were accelerated. Displacements, together with along-strike and across-strike internal deformation in all

  19. Optical domain analog to digital conversion methods and apparatus

    DOEpatents

    Vawter, Gregory A

    2014-05-13

    Methods and apparatus for optical analog to digital conversion are disclosed. An optical signal is converted by mapping the optical analog signal onto a wavelength modulated optical beam, passing the mapped beam through interferometers to generate analog bit representation signals, and converting the analog bit representation signals into an optical digital signal. A photodiode receives an optical analog signal, a wavelength modulated laser coupled to the photodiode maps the optical analog signal to a wavelength modulated optical beam, interferometers produce an analog bit representation signal from the mapped wavelength modulated optical beam, and sample and threshold circuits corresponding to the interferometers produce a digital bit signal from the analog bit representation signal.

  20. Rotation Periods and Ages of Solar Analogs and Solar Twins Revealed by the Kepler Mission

    NASA Astrophysics Data System (ADS)

    do Nascimento, J.-D., Jr.; García, R. A.; Mathur, S.; Anthony, F.; Barnes, S. A.; Meibom, S.; da Costa, J. S.; Castro, M.; Salabert, D.; Ceillier, T.

    2014-08-01

    A new sample of solar analogs and twin candidates has been constructed and studied, paying particular attention to their light curves from NASA's Kepler mission. This Letter aims to assess their evolutionary status, derive their rotation and ages, and identify those which are solar analogs or solar twin candidates. We separate out the subgiants that compose a large fraction of the asteroseismic sample, and which show an increase in the average rotation period as the stars ascend the subgiant branch. The rotation periods of the dwarfs, ranging from 6 to 30 days and averaging 19 days, allow us to assess their individual evolutionary states on the main sequence and to derive their ages using gyrochronology. These ages are found to be in agreement with a correlation coefficient of r = 0.79 with independent asteroseismic ages, where available. As a result of this investigation, we are able to identify 34 stars as solar analogs and 22 of them as solar twin candidates.

  1. Methoxylation Enhances Stilbene Bioactivity in Caenorhabditis elegans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background. Stilbenes are 1,2-diphenylethylene congeners produced by plants in response to stress. Many stilbenes also exhibit xenobiotic activities in animal cells, such as inhibition of cancer cell growth, neuroprotection, and immune modulation. In vivo, hydroxylated stilbenes are metabolized by...

  2. Influences of Stocking Salmon Carcass Analogs on Salmonids in Yakima River Tributaries, 2001-2002 Technical Report.

    SciTech Connect

    Pearsons, Todd N.; Johnson, Christopher L.

    2003-04-01

    The benefits that marine derived nutrients from adult salmon carcasses provide to juvenile salmonids are increasingly being recognized. Current estimates suggest that only 6-7% of marine-derived nitrogen and phosphorus that were historically available to salmonids in the Pacific Northwest are currently available. Food limitation may be a major constraint limiting the restoration of salmonids. A variety of methods have been proposed to offset this nutrient deficit including: allowing greater salmon spawning escapement, stocking hatchery salmon carcasses, and stocking inorganic nutrients. Unfortunately, each of these methods has some ecological or socio-economic shortcoming. We intend to overcome many of these shortcomings by making and evaluating a pathogen free product that simulates a salmon carcass (analog). Abundant sources of marine derived nutrients are available such as fish offal from commercial fishing and salmon carcasses from hatcheries. However, a method for recycling these nutrients into a pathogen free analog that degrades at a similar rate as a natural salmon carcass has never been developed. We endeavored to (1) develop a salmon carcass analog that will increase the food available to salmonids, (2) determine the pathways that salmonids use to acquire food from analogs, and (3) determine the benefits to salmonids and the potential for application to salmonid restoration. We used a before-after-control-impact-paired design in six tributaries of the upper Yakima basin to determine the utility of stocking carcass analogs. Our preliminary results suggest that the introduction of carcass analogs into food-limited streams can be used to restore food pathways previously provided by anadromous salmon. The analogs probably reproduced both of the major food pathways that salmon carcasses produce: direct consumption and food chain enhancement. Trout and salmon fed directly on the carcass analogs during the late summer and presumably benefited from the increased

  3. Exploring the Use of Multiple Analogical Models when Teaching and Learning Chemical Equilibrium

    ERIC Educational Resources Information Center

    Harrison, Allan G.; De Jong, Onno

    2005-01-01

    This study describes the multiple analogical models used to introduce and teach Grade 12 chemical equilibrium. We examine the teacher's reasons for using models, explain each model's development during the lessons, and analyze the understandings students derived from the models. A case study approach was used and the data were drawn from the…

  4. Analogy, higher order thinking, and education.

    PubMed

    Richland, Lindsey Engle; Simms, Nina

    2015-01-01

    Analogical reasoning, the ability to understand phenomena as systems of structured relationships that can be aligned, compared, and mapped together, plays a fundamental role in the technology rich, increasingly globalized educational climate of the 21st century. Flexible, conceptual thinking is prioritized in this view of education, and schools are emphasizing 'higher order thinking', rather than memorization of a cannon of key topics. The lack of a cognitively grounded definition for higher order thinking, however, has led to a field of research and practice with little coherence across domains or connection to the large body of cognitive science research on thinking. We review literature on analogy and disciplinary higher order thinking to propose that relational reasoning can be productively considered the cognitive underpinning of higher order thinking. We highlight the utility of this framework for developing insights into practice through a review of mathematics, science, and history educational contexts. In these disciplines, analogy is essential to developing expert-like disciplinary knowledge in which concepts are understood to be systems of relationships that can be connected and flexibly manipulated. At the same time, analogies in education require explicit support to ensure that learners notice the relevance of relational thinking, have adequate processing resources available to mentally hold and manipulate relations, and are able to recognize both the similarities and differences when drawing analogies between systems of relationships.

  5. An analog silicon retina with multichip configuration.

    PubMed

    Kameda, Seiji; Yagi, Tetsuya

    2006-01-01

    The neuromorphic silicon retina is a novel analog very large scale integrated circuit that emulates the structure and the function of the retinal neuronal circuit. We fabricated a neuromorphic silicon retina, in which sample/hold circuits were embedded to generate fluctuation-suppressed outputs in the previous study [1]. The applications of this silicon retina, however, are limited because of a low spatial resolution and computational variability. In this paper, we have fabricated a multichip silicon retina in which the functional network circuits are divided into two chips: the photoreceptor network chip (P chip) and the horizontal cell network chip (H chip). The output images of the P chip are transferred to the H chip with analog voltages through the line-parallel transfer bus. The sample/hold circuits embedded in the P and H chips compensate for the pattern noise generated on the circuits, including the analog communication pathway. Using the multichip silicon retina together with an off-chip differential amplifier, spatial filtering of the image with an odd- and an even-symmetric orientation selective receptive fields was carried out in real time. The analog data transfer method in the present multichip silicon retina is useful to design analog neuromorphic multichip systems that mimic the hierarchical structure of neuronal networks in the visual system.

  6. Analog forecasting with dynamics-adapted kernels

    NASA Astrophysics Data System (ADS)

    Zhao, Zhizhen; Giannakis, Dimitrios

    2016-09-01

    Analog forecasting is a nonparametric technique introduced by Lorenz in 1969 which predicts the evolution of states of a dynamical system (or observables defined on the states) by following the evolution of the sample in a historical record of observations which most closely resembles the current initial data. Here, we introduce a suite of forecasting methods which improve traditional analog forecasting by combining ideas from kernel methods developed in harmonic analysis and machine learning and state-space reconstruction for dynamical systems. A key ingredient of our approach is to replace single-analog forecasting with weighted ensembles of analogs constructed using local similarity kernels. The kernels used here employ a number of dynamics-dependent features designed to improve forecast skill, including Takens’ delay-coordinate maps (to recover information in the initial data lost through partial observations) and a directional dependence on the dynamical vector field generating the data. Mathematically, our approach is closely related to kernel methods for out-of-sample extension of functions, and we discuss alternative strategies based on the Nyström method and the multiscale Laplacian pyramids technique. We illustrate these techniques in applications to forecasting in a low-order deterministic model for atmospheric dynamics with chaotic metastability, and interannual-scale forecasting in the North Pacific sector of a comprehensive climate model. We find that forecasts based on kernel-weighted ensembles have significantly higher skill than the conventional approach following a single analog.

  7. An analog integrated-circuit vocal tract.

    PubMed

    Keng Hoong Wee; Turicchia, L; Sarpeshkar, R

    2008-12-01

    We present the first experimental integrated-circuit vocal tract by mapping fluid volume velocity to current, fluid pressure to voltage, and linear and nonlinear mechanical impedances to linear and nonlinear electrical impedances. The 275 muW analog vocal tract chip includes a 16-stage cascade of two-port pi-elements that forms a tunable transmission line, electronically variable impedances, and a current source as the glottal source. A nonlinear resistor models laminar and turbulent flow in the vocal tract. The measured SNR at the output of the analog vocal tract is 64, 66, and 63 dB for the first three formant resonances of a vocal tract with uniform cross-sectional area. The analog vocal tract can be used with auditory processors in a feedback speech locked loop-analogous to a phase locked loop-to implement speech recognition that is potentially robust in noise. Our use of a physiological model of the human vocal tract enables the analog vocal tract chip to synthesize speech signals of interest, using articulatory parameters that are intrinsically compact and linearly interpolatable. PMID:23853134

  8. Analogy, higher order thinking, and education.

    PubMed

    Richland, Lindsey Engle; Simms, Nina

    2015-01-01

    Analogical reasoning, the ability to understand phenomena as systems of structured relationships that can be aligned, compared, and mapped together, plays a fundamental role in the technology rich, increasingly globalized educational climate of the 21st century. Flexible, conceptual thinking is prioritized in this view of education, and schools are emphasizing 'higher order thinking', rather than memorization of a cannon of key topics. The lack of a cognitively grounded definition for higher order thinking, however, has led to a field of research and practice with little coherence across domains or connection to the large body of cognitive science research on thinking. We review literature on analogy and disciplinary higher order thinking to propose that relational reasoning can be productively considered the cognitive underpinning of higher order thinking. We highlight the utility of this framework for developing insights into practice through a review of mathematics, science, and history educational contexts. In these disciplines, analogy is essential to developing expert-like disciplinary knowledge in which concepts are understood to be systems of relationships that can be connected and flexibly manipulated. At the same time, analogies in education require explicit support to ensure that learners notice the relevance of relational thinking, have adequate processing resources available to mentally hold and manipulate relations, and are able to recognize both the similarities and differences when drawing analogies between systems of relationships. PMID:26263071

  9. NaturAnalogs for the Unsaturated Zone

    SciTech Connect

    A. Simmons; A. Unger; M. Murrell

    2000-03-08

    The purpose of this Analysis/Model Report (AMR) is to document natural and anthropogenic (human-induced) analog sites and processes that are applicable to flow and transport processes expected to occur at the potential Yucca Mountain repository in order to build increased confidence in modeling processes of Unsaturated Zone (UZ) flow and transport. This AMR was prepared in accordance with ''AMR Development Plan for U0135, Natural Analogs for the UZ'' (CRWMS 1999a). Knowledge from analog sites and processes is used as corroborating information to test and build confidence in flow and transport models of Yucca Mountain, Nevada. This AMR supports the Unsaturated Zone (UZ) Flow and Transport Process Model Report (PMR) and the Yucca Mountain Site Description. The objectives of this AMR are to test and build confidence in the representation of UZ processes in numerical models utilized in the UZ Flow and Transport Model. This is accomplished by: (1) applying data from Boxy Canyon, Idaho in simulations of UZ flow using the same methodologies incorporated in the Yucca Mountain UZ Flow and Transport Model to assess the fracture-matrix interaction conceptual model; (2) Providing a preliminary basis for analysis of radionuclide transport at Pena Blanca, Mexico as an analog of radionuclide transport at Yucca Mountain; and (3) Synthesizing existing information from natural analog studies to provide corroborating evidence for representation of ambient and thermally coupled UZ flow and transport processes in the UZ Model.

  10. Airframe Noise Prediction by Acoustic Analogy: Revisited

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Casper, Jay H.; Tinetti, A.; Dunn, M. H.

    2006-01-01

    The present work follows a recent survey of airframe noise prediction methodologies. In that survey, Lighthill s acoustic analogy was identified as the most prominent analytical basis for current approaches to airframe noise research. Within this approach, a problem is typically modeled with the Ffowcs Williams and Hawkings (FW-H) equation, for which a geometry-independent solution is obtained by means of the use of the free-space Green function (FSGF). Nonetheless, the aeroacoustic literature would suggest some interest in the use of tailored or exact Green s function (EGF) for aerodynamic noise problems involving solid boundaries, in particular, for trailing edge (TE) noise. A study of possible applications of EGF for prediction of broadband noise from turbulent flow over an airfoil surface and the TE is, therefore, the primary topic of the present work. Typically, the applications of EGF in the literature have been limited to TE noise prediction at low Mach numbers assuming that the normal derivative of the pressure vanishes on the airfoil surface. To extend the application of EGF to higher Mach numbers, the uniqueness of the solution of the wave equation when either the Dirichlet or the Neumann boundary condition (BC) is specified on a deformable surface in motion. The solution of Lighthill s equation with either the Dirichlet or the Neumann BC is given for such a surface using EGFs. These solutions involve both surface and volume integrals just like the solution of FW-H equation using FSGF. Insight drawn from this analysis is evoked to discuss the potential application of EGF to broadband noise prediction. It appears that the use of a EGF offers distinct advantages for predicting TE noise of an airfoil when the normal pressure gradient vanishes on the airfoil surface. It is argued that such an approach may also apply to an airfoil in motion. However, for the prediction of broadband noise not directly associated with a trailing edge, the use of EGF does not

  11. Structural characterization of native high-methoxylated pectin using nuclear magnetic resonance spectroscopy and ultraviolet matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Comparative use of 2,5-dihydroxybenzoic acid and nor-harmane as UV-MALDI matrices.

    PubMed

    Monge, María Eugenia; Negri, R Martín; Kolender, Adriana A; Erra-Balsells, Rosa

    2007-01-01

    The successful analysis by ultraviolet matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (UV-MALDI-TOF MS) of native and hydrolyzed high-methoxylated pectin samples is described. In order to find the optimal conditions for UV-MALDI-TOF MS analysis several experimental variables were studied such as: different UV-MALDI matrices (nor-harmane, 2,5-dihydroxybenzoic acid), sample preparation methods (mixture, sandwich), inorganic salt addition (doping salts, NaCl, KCl, NH(4)Cl), ion mode (positive, negative), linear and reflectron mode, etc. nor-Harmane has never been used as a UV-MALDI matrix for the analysis of pectins but its use avoids pre-treatment of the sample, such as an enzymatic digestion or an acid hydrolysis, and there is no need to add salts, making the analysis easier and faster. This study suggested an alternative way of analyzing native high-methoxylated pectins, with UV-MALDI-TOF MS, by using nor-harmane as the matrix in negative ion mode. The analysis by (1)H and (13)C nuclear magnetic resonance (NMR) spectroscopy of the native and hydrolyzed pectin is also briefly described.

  12. Not All Analogies Are Created Equal: Associative and Categorical Analogy Processing following Brain Damage

    ERIC Educational Resources Information Center

    Schmidt, Gwenda L.; Cardillo, Eileen R.; Kranjec, Alexander; Lehet, Matthew; Widick, Page; Chatterjee, Anjan

    2012-01-01

    Current research on analogy processing assumes that different conceptual relations are treated similarly. However, just as words and concepts are related in distinct ways, different kinds of analogies may employ distinct types of relationships. An important distinction in how words are related is the difference between associative (dog-bone) and…

  13. Students' Pre- and Post-Teaching Analogical Reasoning when They Draw Their Analogies

    ERIC Educational Resources Information Center

    Mozzer, Nilmara Braga; Justi, Rosaria

    2012-01-01

    Analogies are parts of human thought. From them, we can acquire new knowledge or change that which already exists in our cognitive structure. In this sense, understanding the analogical reasoning process becomes an essential condition to understand how we learn. Despite the importance of such an understanding, there is no general agreement in…

  14. Analogy-Enhanced Instruction: Effects on Reasoning Skills in Science

    ERIC Educational Resources Information Center

    Remigio, Krisette B.; Yangco, Rosanelia T.; Espinosa, Allen A.

    2014-01-01

    The study examined the reasoning skills of first year high school students after learning general science concepts through analogies. Two intact heterogeneous sections were randomly assigned to Analogy-Enhanced Instruction (AEI) group and Non Analogy-Enhanced (NAEI) group. Various analogies were incorporated in the lessons of the AEI group for…

  15. The Importance of Explicitly Mapping Instructional Analogies in Science Education

    ERIC Educational Resources Information Center

    Asay, Loretta Johnson

    2013-01-01

    Analogies are ubiquitous during instruction in science classrooms, yet research about the effectiveness of using analogies has produced mixed results. An aspect seldom studied is a model of instruction when using analogies. The few existing models for instruction with analogies have not often been examined quantitatively. The Teaching With…

  16. Space flight nutrition research: platforms and analogs

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; Uchakin, Peter N.; Tobin, Brian W.

    2002-01-01

    Conducting research during actual or simulated weightlessness is a challenging endeavor, where even the simplest activities may present significant challenges. This article reviews some of the potential obstacles associated with performing research during space flight and offers brief descriptions of current and previous space research platforms and ground-based analogs, including those for human, animal, and cell-based research. This review is intended to highlight the main issues of space flight research analogs and leave the specifics for each physiologic system for the other papers in this section.

  17. Analog graphic display method and apparatus

    DOEpatents

    Kronberg, J.W.

    1991-08-13

    Disclosed are an apparatus and method for using an output device such as an LED to show the approximate analog level of a variable electrical signal wherein a modulating AC waveform is superimposed either on the signal or a reference voltage, both of which are then fed to a comparator which drives the output device. Said device flashes at a constant perceptible rate with a duty cycle which varies in response to variations in the level of the input signal. The human eye perceives these variations in duty cycle as analogous to variations in the level of the input signal. 21 figures.

  18. Associative Pattern Recognition In Analog VLSI Circuits

    NASA Technical Reports Server (NTRS)

    Tawel, Raoul

    1995-01-01

    Winner-take-all circuit selects best-match stored pattern. Prototype cascadable very-large-scale integrated (VLSI) circuit chips built and tested to demonstrate concept of electronic associative pattern recognition. Based on low-power, sub-threshold analog complementary oxide/semiconductor (CMOS) VLSI circuitry, each chip can store 128 sets (vectors) of 16 analog values (vector components), vectors representing known patterns as diverse as spectra, histograms, graphs, or brightnesses of pixels in images. Chips exploit parallel nature of vector quantization architecture to implement highly parallel processing in relatively simple computational cells. Through collective action, cells classify input pattern in fraction of microsecond while consuming power of few microwatts.

  19. Parallel Analog-to-Digital Image Processor

    NASA Technical Reports Server (NTRS)

    Lokerson, D. C.

    1987-01-01

    Proposed integrated-circuit network of many identical units convert analog outputs of imaging arrays of x-ray or infrared detectors to digital outputs. Converter located near imaging detectors, within cryogenic detector package. Because converter output digital, lends itself well to multiplexing and to postprocessing for correction of gain and offset errors peculiar to each picture element and its sampling and conversion circuits. Analog-to-digital image processor is massively parallel system for processing data from array of photodetectors. System built as compact integrated circuit located near local plane. Buffer amplifier for each picture element has different offset.

  20. Landauer bound for analog computing systems.

    PubMed

    Diamantini, M Cristina; Gammaitoni, Luca; Trugenberger, Carlo A

    2016-07-01

    By establishing a relation between information erasure and continuous phase transitions we generalize the Landauer bound to analog computing systems. The entropy production per degree of freedom during erasure of an analog variable (reset to standard value) is given by the logarithm of the configurational volume measured in units of its minimal quantum. As a consequence, every computation has to be carried on with a finite number of bits and infinite precision is forbidden by the fundamental laws of physics, since it would require an infinite amount of energy. PMID:27575108

  1. Landauer bound for analog computing systems

    NASA Astrophysics Data System (ADS)

    Diamantini, M. Cristina; Gammaitoni, Luca; Trugenberger, Carlo A.

    2016-07-01

    By establishing a relation between information erasure and continuous phase transitions we generalize the Landauer bound to analog computing systems. The entropy production per degree of freedom during erasure of an analog variable (reset to standard value) is given by the logarithm of the configurational volume measured in units of its minimal quantum. As a consequence, every computation has to be carried on with a finite number of bits and infinite precision is forbidden by the fundamental laws of physics, since it would require an infinite amount of energy.

  2. Synthetic heparin-binding factor analogs

    DOEpatents

    Pena, Louis A.; Zamora, Paul O.; Lin, Xinhua; Glass, John D.

    2010-04-20

    The invention provides synthetic heparin-binding growth factor analogs having at least one peptide chain, and preferably two peptide chains branched from a dipeptide branch moiety composed of two trifunctional amino acid residues, which peptide chain or chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a linker, which may be a hydrophobic linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

  3. Analog graphic display method and apparatus

    DOEpatents

    Kronberg, James W.

    1991-01-01

    An apparatus and method for using an output device such as an LED to show the approximate analog level of a variable electrical signal wherein a modulating AC waveform is superimposed either on the signal or a reference voltage, both of which are then fed to a comparator which drives the output device. Said device flashes at a constant perceptible rate with a duty cycle which varies in response to variations in the level of the input signal. The human eye perceives these variations in duty cycle as analogous to variations in the level of the input signal.

  4. Ground-water studies and analog models

    USGS Publications Warehouse

    Robinove, Charles Joseph

    1962-01-01

    Hydrologists make ground-water studies to aid managers and users of water resources in solving their problems in the development and management of ground water. Geologic and hydrologic information provides the basic knowledge for construction of electric analog models that portray the ground-water system in miniature. Analog models can be analyzed electrically, and the results of the analysis are presented in terms of the ground-water system so that the effects of alternative methods of water development can be assessed.

  5. Increased urinary excretion of analogs of Krebs cycle metabolites and arabinose in two brothers with autistic features.

    PubMed

    Shaw, W; Kassen, E; Chaves, E

    1995-08-01

    A marked increase in analogs of Krebs cycle metabolites was found in the urine of two brothers with autistic features. These metabolites included citramalic, tartaric (3-OH-malic), and 3-oxoglutaric acids and compounds tentatively identified as a citric acid analog and partially identified as a phenylcarboxylic acid by the fragmentation pattern of the trimethylsilyl (TMS) derivatives of the compounds and mass shifts of the same compounds derivatized with perdeuterated N,O-bis(trimethylsilyl)trifluoroacetamide. The molecular mass of the TMS derivative of the tentatively identified citric acid analog was 596 Da, based on a finding of a significant M - 15 ion at m/z 581. The citric acid analog was excreted in quantities as high as 137 mmol/mol creatinine, based on the response factor of citric acid as a surrogate calibrator. A carbohydrate with a retention time and mass spectrum identical to arabinose was also found in high concentrations in the urine of these brothers.

  6. Automatic derivation of formal software specifications from informal descriptions

    NASA Technical Reports Server (NTRS)

    Miriyala, Kanth; Harandi, Mehdi T.

    1991-01-01

    SPECIFIER, an interactive system which derives formal specifications of data types and programs from their informal descriptions, is described. The process of deriving formal specifications is viewed as a problem-solving process. The system uses common problem-solving techniques such as schemas, analogy, and difference-based reasoning to derive formal specifications. If an informal description is a commonly occurring operation for which the system has a schema, then the formal specification is derived by instantiating the schema. If there is no such schema, SPECIFIER tries to find a previously solved problem which is analogous to the current problem. If the problem found is directly analogous to the current problem, it applies an analogy mapping to obtain a formal specification. On the other hand, if the analogy found is only approximate, it solves the directly analogous part of the problem by analogy and performs difference-based reasoning using the remaining (unmatched) parts to transform the formal specification obtained by analogy to a formal specification for the entire original problem.

  7. Synthesis and biological evaluation of trehalose analogs as potential inhibitors of mycobacterial cell wall biosynthesis.

    PubMed

    Rose, Jerry D; Maddry, Joseph A; Comber, Robert N; Suling, William J; Wilson, Larry N; Reynolds, Robert C

    2002-02-01

    Analogs of trehalose are reported that were designed to interfere with mycolylation pathways in the mycobacterial cell wall. Several derivatives of 6,6'-dideoxytrehalose, including N,N'-dialkylamino and 6,6'-bis(sulfonamido) analogs, were prepared and evaluated for antimycobacterial activity against Mycobacterium tuberculosis H(37)Ra and a panel of clinical isolates of Mycobacterium avium. 6,6'-Diaminotrehalose and its diazido precursor were both inactive, but significant activity apparently related to aliphatic chain length was found among the sulfonamides, N-alkylamines, and one of the amidines. PMID:11814442

  8. Analogies between optical propagation and heat diffusion: applications to microcavities, gratings and cloaks

    PubMed Central

    Amra, C.; Petiteau, D.; Zerrad, M.; Guenneau, S.; Soriano, G.; Gralak, B.; Bellieud, M.; Veynante, D.; Rolland, N.

    2015-01-01

    A new analogy between optical propagation and heat diffusion in heterogeneous anisotropic media has been proposed recently by three of the present authors. A detailed derivation of this unconventional correspondence is presented and developed. In time harmonic regime, all thermal parameters are related to optical ones in artificial metallic media, thus making possible to use numerical codes developed for optics. Then, the optical admittance formalism is extended to heat conduction in multilayered structures. The concepts of planar microcavities, diffraction gratings and planar transformation optics for heat conduction are addressed. Results and limitations of the analogy are emphasized. PMID:26730214

  9. (-)-Botryodiplodin, A Unique Ribose Analog Toxin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many toxins owe their mechanisms of action to being structural analogs of essential metabolites, messengers or structural components. Examples range from tubo-curare to penicillin. Ribose plays a unique role in the metabolism of living organisms, whether prokaryotes or eukaryotes. It and its deri...

  10. The GMO-Nanotech (Dis)Analogy?

    ERIC Educational Resources Information Center

    Sandler, Ronald; Kay, W. D.

    2006-01-01

    The genetically-modified-organism (GMO) experience has been prominent in motivating science, industry, and regulatory communities to address the social and ethical dimensions of nanotechnology. However, there are some significant problems with the GMO-nanotech analogy. First, it overstates the likelihood of a GMO-like backlash against…

  11. Invention through Form and Function Analogy

    ERIC Educational Resources Information Center

    Rule, Audrey C.

    2015-01-01

    "Invention through Form and Function Analogy" is an invention book for teachers and other leaders working with youth who are involving students in the invention process. The book consists of an introduction and set of nine learning cycle formatted lessons for teaching the principles of invention through the science and engineering design…

  12. A Mechanical Analogy for Ohm's Law.

    ERIC Educational Resources Information Center

    do Couto Tavares, Milton; And Others

    1991-01-01

    A mechanical analogy between the microscopic motion of a charged carrier in an ordinary resistor and the macroscopic motion of a ball falling along a slanted board covered with a lattice of nails is introduced. The Drude model is also introduced to include the case of inelastic collisions. Computer simulation of the motion is described. (KR)

  13. Radiation Behavior of Analog Neural Network Chip

    NASA Technical Reports Server (NTRS)

    Langenbacher, H.; Zee, F.; Daud, T.; Thakoor, A.

    1996-01-01

    A neural network experiment conducted for the Space Technology Research Vehicle (STRV-1) 1-b launched in June 1994. Identical sets of analog feed-forward neural network chips was used to study and compare the effects of space and ground radiation on the chips. Three failure mechanisms are noted.

  14. An Analog Processor for Image Compression

    NASA Technical Reports Server (NTRS)

    Tawel, R.

    1992-01-01

    This paper describes a novel analog Vector Array Processor (VAP) that was designed for use in real-time and ultra-low power image compression applications. This custom CMOS processor is based architectually on the Vector Quantization (VQ) algorithm in image coding, and the hardware implementation fully exploits the inherent parallelism built-in the VQ algorithm.

  15. RF digital-to-analog converter

    DOEpatents

    Conway, P.H.; Yu, D.U.L.

    1995-02-28

    A digital-to-analog converter is disclosed for producing an RF output signal proportional to a digital input word of N bits from an RF reference input, N being an integer greater or equal to 2. The converter comprises a plurality of power splitters, power combiners and a plurality of mixers or RF switches connected in a predetermined configuration. 18 figs.

  16. Classical analog of electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Garrido Alzar, C. L.; Martinez, M. A. G.; Nussenzveig, P.

    2002-01-01

    We present a classical analog of electromagnetically induced transparency (EIT). In a system of just two coupled harmonic oscillators subject to a harmonic driving force, we reproduce the phenomenology observed in EIT. We also describe a simple experiment with two linearly coupled RLC circuits which can be incorporated into an undergraduate laboratory.

  17. Analog Acoustic Expression in Speech Communication

    ERIC Educational Resources Information Center

    Shintel, Hadas; Nusbaum, Howard C.; Okrent, Arika

    2006-01-01

    We present the first experimental evidence of a phenomenon in speech communication we call "analog acoustic expression." Speech is generally thought of as conveying information in two distinct ways: discrete linguistic-symbolic units such as words and sentences represent linguistic meaning, and continuous prosodic forms convey information about…

  18. Duplex stabilities of phosphorothioate, methylphosphonate, and RNA analogs of two DNA 14-mers.

    PubMed Central

    Kibler-Herzog, L; Zon, G; Uznanski, B; Whittier, G; Wilson, W D

    1991-01-01

    The duplex stabilities of various phosphorothioate, methylphosphonate, RNA and 2'-OCH3 RNA analogs of two self-complementary DNA 14-mers are compared. Phosphorothioate and/or methylphosphonate analogs of the two sequences d(TAATTAATTAATTA) [D1] and d(TAGCTAATTAGCTA) [D2] differ in the number, position, or chirality (at the 5' terminal linkage) of the modified phosphates. Phosphorothioate derivatives of D1 are found to be less destabilized when the linkage modified is between adenines rather than between thymines. Surprisingly, no base sequence effect on duplex stabilization is observed for any methylphosphonate derivatives of D1 or D2. Highly modified phosphorothioates or methylphosphonates are less stable than their partially modified counterparts which are less stable than the unmodified parent compounds. The 'normal' (2'-OH) RNA analog of duplex D1 is slightly destabilized, whereas the 2'-OCH3 RNA derivative is significantly stabilized relative to the unmodified DNA. For the D1 sequence, at approximately physiological salt concentration, the order of duplex stability is 2'-OCH3 RNA greater than unmodified DNA greater than 'normal' RNA greater than methylphosphonate DNA greater than phosphorothioate DNA. D2 and the various D2 methylphosphonate analogs investigated all formed hairpin conformations at low salt concentrations. PMID:1711677

  19. Radioiodinated fatty acid analogs for myocardial imaging

    SciTech Connect

    Ruyan, M.K.

    1993-01-01

    Fatty acids are the preferred substrate for the normoxic heart. About sixty percent of the energy required by the myocardium is provided by fatty acid [beta]-oxidation. Many scientists have focused on the alterations in fatty acid metabolism in the ischemic heart for the development of radiolabelled fatty acids for functional imaging of the heart. Three main categories of compounds were synthesized: tetrazoles (1 and 2), glycidic and [alpha]-methylene acids (3-5), and analogs of oleic acid (6,7 and 7A). The tetrazole group has a similar pKa and size to that of a carboxyl group; however, such fatty acid analogs cannot undergo normal fatty acid metabolism. Glycidic and [alpha]-methylene analogs are potential irreversible inhibitors of fatty acid metabolism. Oleic acid analogs were investigated to assess the affect of stereochemical consequences on biodistribution. The key intermediates in the synthesis of the target compounds were [omega]-nitrophenyl alkylcarboxylic acids and alcohols, which were made using a variety of cross-coupling reactions. The Wittig reaction, which was used in the synthesis of tetrazole 1 and glycidic acid 3, gave low yields of the cross-coupled products. The remaining target compounds were synthesized by condensation of appropriate RCu (CN) ZnI and substituted benzyl bromides or by Pd[sup II] catalyzed cross-coupling of substituted arylhalides with suitable alkynes. The latter two reactions produced much higher yields of the desired products. All of the target compounds were radiolabeled with [sup 125]I by various Cu(I) catalyzed radioiodine exchange procedures and were then subjected to tissue biodistribution (TD) studies in rats. Except for the 15-(4-iodophenyl)-2-methylene-pentadecanoic acid (5), all of the fatty acid analogs failed to surpass clinically-used 15-(4-iodophenyl)pentadecanoic acid (IPPA) in their ability to be taken up and retained by the rat myocardium.

  20. ANALOGY AND DISANALOGY IN PRODUCTION AND PERCEPTION OF SPEECH

    PubMed Central

    Remez, Robert E.

    2014-01-01

    A varied psychological vocabulary now describes the cognitive and social conditions of language production, the ultimate result of which is the mechanical action of vocal musculature in spoken expression. Following the logic of the speech chain, descriptions of production have often exhibited a clear analogy to accounts of perception. This reciprocality is especially evident in explanations that rely on reafference to control production, on articulation to inform perception, and on strict parity between produced and perceived form to provide invariance in the relation between abstract linguistic objects and observed expression. However, a causal account of production and perception cannot derive solely from this hopeful analogy. Despite sharing of abstract linguistic representations, the control functions in production and perception as well as the constraints on their use stand in fundamental disanalogy. This is readily seen in the different adaptive challenges to production — to speak in a single voice — and perception — to resolve familiar linguistic properties in any voice. This acknowledgment sets descriptive and theoretical challenges that break the symmetry of production and perception. As a consequence, this recognition dislodges an old impasse between the psychoacoustic and motoric accounts in the regulation of production and perception. PMID:25642428

  1. Exact solutions and physical analogies for unidirectional flows

    NASA Astrophysics Data System (ADS)

    Bazant, Martin Z.

    2016-06-01

    Unidirectional flow is the simplest phenomenon of fluid mechanics. Its mathematical description, the Dirichlet problem for Poisson's equation in two dimensions with constant forcing, arises in many physical contexts, such as the torsion of elastic beams, first solved by de Saint-Venant for complex shapes. Here the literature is unified and extended by identifying 17 physical analogies for unidirectional flow and describing their common mathematical structure. Besides classical analogies in fluid and solid mechanics, applications are discussed in stochastic processes (first passage in two dimensions), pattern formation (river growth by erosion), and electrokinetics (ion transport in nanochannels), which also involve Poisson's equation with nonconstant forcing. Methods are given to construct approximate geometries that admit exact solutions, by adding harmonic functions to quadratic forms or by truncating eigenfunction expansions. Exact solutions for given geometries are also derived by conformal mapping. We prove that the remarkable geometrical interpretation of Poiseuille flow in an equilateral triangular pipe (the product of the distances from an interior point to the sides) is only shared by parallel plates and unbounded equilateral wedges (with the third side hidden behind the apex). We also prove Onsager reciprocity for linear electrokinetic phenomena in straight pores of arbitrary shape and surface charge, based on the mathematics of unidirectional flow.

  2. Influences of Stocking Salmon Carcass Analogs on Salmonids in Klickitat River Tributaries, 2001-2005 Completion Report.

    SciTech Connect

    Zendt, Joe; Sharp, Bill

    2006-09-01

    This report describes the work completed by the Yakama Nation Fisheries Program (YNFP) in the Klickitat subbasin in south-central Washington under BPA innovative project No.200105500--Influences of stocking salmon carcass analogs on salmonids in Columbia River Tributaries. Salmon carcasses historically provided a significant source of marine-derived nutrients to many stream systems in the Columbia basin, and decreased run sizes have led to a loss of this nutrient source in many streams. Partners in this project developed a pathogen-free carcass analog and stocked the analogs in streams with the following objectives: restoring food availability to streams with reduced anadromous salmon returns; mimicking the natural pathways and timing of food acquisition by salmonids; minimizing unintended negative ecological effects; and increasing the growth and survival of salmonids. In the Klickitat subbasin, carcass analogs were stocked in two streams in 2002 and 2003; a third stream was used as a control. Salmonid fish abundance, growth, and stomach contents were monitored in all three streams before and after carcass analog placement. Fish, invertebrate, and periphyton samples were also collected for stable isotope analysis (to determine if nutrients from carcass analogs were incorporated into the stream food web). Water quality samples were also collected to determine if nutrient overloading occurred in streams. Significant differences in growth were found between fish in treated and untreated stream reaches. Fish in treatment reaches exhibited higher instantaneous growth rates approximately one month after the first carcass analog stocking. Stomach contents sampling indicated that salmonid fish routinely consumed the carcass analog material directly, and that stomach fullness of fish in treatment reaches was higher than in untreated reaches in the first few weeks following carcass analog stockings. No significant differences were detected in fish abundance between

  3. Semisynthetic Derivatives of Epothilones

    NASA Astrophysics Data System (ADS)

    Altmann, Karl-Heinz

    Semisynthetic derivatives of natural products traditionally occupy a prominent space in natural-product-based drug discovery (1, 2). As many biologically active natural products exhibit a high degree of structural complexity (3), the chemical derivatization of material isolated from natural sources often represents the only feasible means (or at least the only economically viable approach) to explore structure-activity-relationships (SAR) and to produce analogs with more favorable pharmacokinetic and pharmacological properties than the natural product lead. Examples of clinically important drugs that are semisynthetic derivatives of natural products exist in virtually all disease areas (1, 2); in the treatment of cancer this includes compounds such as etoposide or teniposide (derived from podophyllotoxin) (4-6), irinotecan and topotecan (derived from camptothecin) (7-9), or docetaxel (derived from 10-deacetylbaccatin III) (10, 11). Even for taxol (11), which is a natural product (12), the sustained supply of sufficient quantities of material for widespread clinical use could only be secured through the development of a semisynthetic production process from another natural product, namely, 10-deacetylbaccatin III (13). In light of these facts, it is not surprising that semisynthesis approaches have also featured prominently in the elucidation of the SAR for epothilones and in the discovery of a number of clinical development candidates.

  4. CRC handbook of neurohypophyseal hormone analogs. Volume I

    SciTech Connect

    Jost, K.; Lebl, M.; Brtnik, F.

    1987-01-01

    This book is discussed in two parts. Part one discusses Introductory Remarks. Nomenclature. Natural Forms of Neurohypophyseal Hormones. Synthesis, Purification, and Stability of the Neurohypophyseal Hormone Analogs. Isotopically Modified Analogs. Studies of Analogs Using Physiocochemical and Theoretical Methods. Conformational properties of Neurohypophyseal Hormone Analogs in Solution as Determined bu NMR and Laser Raman Spectroscopies. Other Methods used in the Investigation of Neurohypophyseal Hormone Analog Conformations. Conformation Properties of Analogs in Solution as Revealed by Circular Dichroism Spectroscopy. Conformational Energy Calculations. Quantitative Structure Activity Relationships. References. Part 2 discusses The Use of Neurohypophyseal Hormone Analogs in the Study of Neurophysin-Hormone Interactions. Enzymatic Inactivation. Immunochemistry. Studies of Neurohypopophyseal Hormone Activities at the Cellular Level. Fundamental Biological Evaluation. Important Structural Modifications. Noncoded Amino Acids. Modification of ..cap alpha..-Amino Group; 1-Deamino and 1-Hydroxy Analogs. Modifications in the Issulfide Bridge (Carba-Analogs). Modification of Other Functional Groups. Changes in the Backbone. References. Index.

  5. Antimicrobial activity of human α-defensin 5 and its linear analogs: N-terminal fatty acylation results in enhanced antimicrobial activity of the linear analogs.

    PubMed

    Mathew, Basil; Nagaraj, Ramakrishnan

    2015-09-01

    Human α-defensin 5 (HD5) exhibits broad spectrum antimicrobial activity and plays an important role in mucosal immunity of the small intestine. Although there have been several studies, the structural requirements for activity and mechanism of bacterial killing is yet to be established unequivocally. In this study, we have investigated the antimicrobial activity of HD5 and linear analogs. Cysteine deletions attenuated the antibacterial activity considerably. Candidacidal activity was affected to a lesser extent. Fatty acid conjugated linear analogs showed antimicrobial activity comparable activity to HD5. Effective surface charge neutralization of bacteria was observed for HD5 as compared to the non-fatty acylated linear analogs. Our results show that HD5 and non-fatty acylated linear analogs enter the bacterial cytoplasm without causing damage to the bacterial inner membrane. Although fatty acylated peptides exhibited antimicrobial activity comparable to HD5, their mechanism of action involved permeabilization of the Escherichia coli inner membrane. HD5 and analogs had the ability to bind plasmid DNA. HD5 had greater binding affinity to plasmid DNA as compared to the analogs. The three dimensional structure of HD5 favors greater interaction with the bacterial cell surface and also with DNA. Antibacterial activity of HD5 involves entry into bacterial cytoplasm and binding to DNA which would result in shut down of the bacterial metabolism leading to cell death. We show how a moderately active linear peptide derived from the α-defensin HD5 can be engineered to enhance antimicrobial activity almost comparable to the native peptide. PMID:26206286

  6. Quantum dynamics as an analog of conditional probability

    SciTech Connect

    Leifer, M. S.

    2006-10-15

    Quantum theory can be regarded as a noncommutative generalization of classical probability. From this point of view, one expects quantum dynamics to be analogous to classical conditional probabilities. In this paper, a variant of the well-known isomorphism between completely positive maps and bipartite density operators is derived, which makes this connection much more explicit. This isomorphism is given an operational interpretation in terms of statistical correlations between ensemble preparation procedures and outcomes of measurements. Finally, the isomorphism is applied to elucidate the connection between no-cloning and no-broadcasting theorems and the monogamy of entanglement, and a simplified proof of the no-broadcasting theorem is obtained as a by-product.

  7. Probability-theoretical analog of the vector Lyapunov function method

    SciTech Connect

    Nakonechnyi, A.N.

    1995-01-01

    The main ideas of the vector Lyapunov function (VLF) method were advanced in 1962 by Bellman and Matrosov. In this method, a Lyapunov function and a comparison equation are constructed for each subsystem. Then the dependences between the subsystems and the effect of external noise are allowed for by constructing a vector Lyapunov function (as a collection of the scalar Lyapunov functions of the subsystems) and an aggregate comparison function for the entire complex system. A probability-theoretical analog of this method for convergence analysis of stochastic approximation processes has been developed. The abstract approach proposed elsewhere eliminates all restrictions on the system phase space, the system trajectories, the class of Lyapunov functions, etc. The analysis focuses only on the conditions that relate sequences of Lyapunov function values with the derivative and ensure a particular type (mode, character) of stability. In our article, we extend this approach to the VLF method for discrete stochastic dynamic systems.

  8. Application of constrained aza-valine analogs for Smac mimicry.

    PubMed

    Chingle, Ramesh; Ratni, Sara; Claing, Audrey; Lubell, William D

    2016-05-01

    Constrained azapeptides were designed based on the Ala-Val-Pro-Ile sequence from the second mitochondria-derived activator of caspases (Smac) protein and tested for ability to induce apoptosis in cancer cells. Diels-Alder cyclizations and Alder-ene reactions on azopeptides enabled construction of a set of constrained aza-valine dipeptide building blocks, that were introduced into mimics using effective coupling conditions to acylate bulky semicarbazide residues. Evaluation of azapeptides 7-11 in MCF-7 breast cancer cells indicated aza-cyclohexanylglycyine analog 11 induced cell death more efficiently than the parent tetrapeptide likely by a caspase-9 mediated apoptotic pathway. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 235-244, 2016.

  9. Design, Synthesis, and Osteogenic Activity of Daidzein Analogs on Human Mesenchymal Stem Cells

    PubMed Central

    2013-01-01

    Osteoporosis is caused by an overstimulation of osteoclast activity and the destruction of the bone extracellular matrix. Without the normal architecture, osteoblast cells are unable to rebuild phenotypically normal bone. Hormone replacement therapy with estrogen has been effective in increasing osteoblast activity but also has resulted in the increased incidence of breast and uterine cancer. In this study we designed and synthesized a series of daidzein analogs to investigate their osteogenic induction potentials. Human bone marrow derived mesenchymal stem cells (MSCs) from three different donors were treated with daidzein analogs and demonstrated enhanced osteogenesis when compared to daidzein treatment. The enhanced osteogenic potential of these daidzein analogs resulted in increased osterix (Sp7), alkaline phosphatase (ALP), osteopontin (OPN), and insulin-like growth factor 1 (IGF-1), which are osteogenic transcription factors that regulate the maturation of osteogenic progenitor cells into mature osteoblast cells. PMID:24900787

  10. Antischistosomal activity of N,N'-arylurea analogs against Schistosoma japonicum.

    PubMed

    Yao, Houzong; Liu, Fengyou; Chen, Jinglei; Li, Yan; Cui, Jinhao; Qiao, Chunhua

    2016-03-01

    Although the antischistosomal activities of N,N'-arylurea analogs were reported, systematic structure-activity relationships have not been conducted. In this Letter, we reported the design, synthesis and evaluation of 45 N,N'-arylurea analogs. Among these prepared compounds, 13 compounds were urea linker modified and 32 were N,N'-arylurea derivatives. The activity evaluation revealed 12 analogs exhibited IC50 values lower than 22.6μM, and 7 of them had IC50 less than 10μM against the juvenile Schistosoma japonicum in vitro. Their worm killing potency was even higher against adult worm. Unfortunately, low to moderate worm burden reduction of 0-33.4% was recorded after administration of a single oral dose of 200mg/kg or 400mg/kg to mice harboring S. japonicum.

  11. Multilateral Research Opportunities in Ground Analogs

    NASA Technical Reports Server (NTRS)

    Corbin, Barbara J.

    2015-01-01

    The global economy forces many nations to consider their national investments and make difficult decisions regarding their investment in future exploration. International collaboration provides an opportunity to leverage other nations' investments to meet common goals. The Humans In Space Community shares a common goal to enable safe, reliable, and productive human space exploration within and beyond Low Earth Orbit. Meeting this goal requires efficient use of limited resources and International capabilities. The International Space Station (ISS) is our primary platform to conduct microgravity research targeted at reducing human health and performance risks for exploration missions. Access to ISS resources, however, is becoming more and more constrained and will only be available through 2020 or 2024. NASA's Human Research Program (HRP) is actively pursuing methods to effectively utilize the ISS and appropriate ground analogs to understand and mitigate human health and performance risks prior to embarking on human exploration of deep space destinations. HRP developed a plan to use ground analogs of increasing fidelity to address questions related to exploration missions and is inviting International participation in these planned campaigns. Using established working groups and multilateral panels, the HRP is working with multiple Space Agencies to invite International participation in a series of 30- day missions that HRP will conduct in the US owned and operated Human Exploration Research Analog (HERA) during 2016. In addition, the HRP is negotiating access to Antarctic stations (both US and non-US), the German :envihab and Russian NEK facilities. These facilities provide unique capabilities to address critical research questions requiring longer duration simulation or isolation. We are negotiating release of international research opportunities to ensure a multilateral approach to future analog research campaigns, hoping to begin multilateral campaigns in the

  12. Not all analogies are created equal: Associative and categorical analogy processing following brain damage

    PubMed Central

    Schmidt, Gwenda L.; Cardillo, Eileen R.; Kranjec, Alexander; Lehet, Matthew; Widick, Page; Chatterjee, Anjan

    2012-01-01

    Current research on analogy processing assumes that different conceptual relations are treated similarly. However, just as words and concepts are related in distinct ways, different kinds of analogies may employ distinct types of relationships. An important distinction in how words are related is the difference between associative (dog-bone) and categorical (dog-cat) relations. To test the hypothesis that analogical mapping of different types of relations would have different neural instantiations, we tested patients with left and right hemisphere lesions on their ability to understand two types of analogies, ones expressing an associative relationship and others expressing a categorical relationship. Voxel-based lesion-symptom mapping (VLSM) and behavioral analyses revealed that associative analogies relied on a large left-lateralized language network while categorical analogies relied on both left and right hemispheres. The verbal nature of the task could account for the left hemisphere findings. We argue that categorical relations additionally rely on the right hemisphere because they are more difficult, abstract, and fragile; and contain more distant relationships. PMID:22402184

  13. Not all analogies are created equal: Associative and categorical analogy processing following brain damage.

    PubMed

    Schmidt, Gwenda L; Cardillo, Eileen R; Kranjec, Alexander; Lehet, Matthew; Widick, Page; Chatterjee, Anjan

    2012-06-01

    Current research on analogy processing assumes that different conceptual relations are treated similarly. However, just as words and concepts are related in distinct ways, different kinds of analogies may employ distinct types of relationships. An important distinction in how words are related is the difference between associative (dog-bone) and categorical (dog-cat) relations. To test the hypothesis that analogical mapping of different types of relations would have different neural instantiations, we tested patients with left and right hemisphere lesions on their ability to understand two types of analogies, ones expressing an associative relationship and others expressing a categorical relationship. Voxel-based lesion-symptom mapping (VLSM) and behavioral analyses revealed that associative analogies relied on a large left-lateralized language network while categorical analogies relied on both left and right hemispheres. The verbal nature of the task could account for the left hemisphere findings. We argue that categorical relations additionally rely on the right hemisphere because they are more difficult, abstract, and fragile, and contain more distant relationships.

  14. Playing with a double-edged sword: Analogies in biochemistry

    NASA Astrophysics Data System (ADS)

    Orgill, Marykay

    Analogy pervades our everyday reasoning. No situation we encounter is exactly like a situation we have encountered previously, and our ability to learn and survive in the world is based on our ability to find similarities between past and present situations and use the knowledge we have gained from past situations to manage current situations. Analogies can be powerful teaching tools because they can make new material intelligible to students by comparing it to material that is already familiar. It is clear, though, that not all analogies are good and that not all good analogies are useful to all students. In this study, I have used textbook analysis, classroom observations, student interviews and instructor interviews to determine the role that analogies play in biochemistry learning. Analogies are an important teaching technique in biochemistry classes, being used more often in both biochemistry classes and textbooks than they are in high school chemistry classes and textbooks. Most biochemistry students like, pay particular attention to, and remember the analogies their instructors provide; and they use these analogies to understand, visualize, and recall information from class. Even though students like and use analogies, they do not understand what analogies are or the mechanism by which they improve learning. For the students, analogies are simply any teaching technique that eases understanding, visualization, or recall. Instructors, on the other hand, have a good understanding of what analogies are and of how they should be presented in class; but they do not use analogies as effectively as they should. They do not plan, explain or identify the limitations of the analogies they use in class. However, regardless of how effectively instructors present analogies in class, this study indicates that, in general, analogies are useful in promoting understanding, visualization, recall, and motivation in biochemistry students at all levels. They would be even more

  15. A new program on digitizing analog seismograms

    NASA Astrophysics Data System (ADS)

    Wang, Maofa; Jiang, Qigang; Liu, Qingjie; Huang, Meng

    2016-08-01

    Historical seismograms contain a great variety of useful information which can be used in the study of earthquakes. It is necessary for researchers to digitize analog records and extract the information just as modern computing analysis requires. Firstly, an algorithm based on color scene filed method is presented in order to digitize analog seismograms. Secondly, an interactive software program using C# has been developed to digitize seismogram traces from raster files quickly and accurately. The program can deal with gray-scale images stored in a suitable file format and it offers two different methods: manual digitization and automatic digitization. The test result of the program shows that the methods presented in this paper can lead to good performance.

  16. Optimal neural computations require analog processors

    SciTech Connect

    Beiu, V.

    1998-12-31

    This paper discusses some of the limitations of hardware implementations of neural networks. The authors start by presenting neural structures and their biological inspirations, while mentioning the simplifications leading to artificial neural networks. Further, the focus will be on hardware imposed constraints. They will present recent results for three different alternatives of parallel implementations of neural networks: digital circuits, threshold gate circuits, and analog circuits. The area and the delay will be related to the neurons` fan-in and to the precision of their synaptic weights. The main conclusion is that hardware-efficient solutions require analog computations, and suggests the following two alternatives: (i) cope with the limitations imposed by silicon, by speeding up the computation of the elementary silicon neurons; (2) investigate solutions which would allow the use of the third dimension (e.g. using optical interconnections).

  17. Analog Computation by DNA Strand Displacement Circuits.

    PubMed

    Song, Tianqi; Garg, Sudhanshu; Mokhtar, Reem; Bui, Hieu; Reif, John

    2016-08-19

    DNA circuits have been widely used to develop biological computing devices because of their high programmability and versatility. Here, we propose an architecture for the systematic construction of DNA circuits for analog computation based on DNA strand displacement. The elementary gates in our architecture include addition, subtraction, and multiplication gates. The input and output of these gates are analog, which means that they are directly represented by the concentrations of the input and output DNA strands, respectively, without requiring a threshold for converting to Boolean signals. We provide detailed domain designs and kinetic simulations of the gates to demonstrate their expected performance. On the basis of these gates, we describe how DNA circuits to compute polynomial functions of inputs can be built. Using Taylor Series and Newton Iteration methods, functions beyond the scope of polynomials can also be computed by DNA circuits built upon our architecture. PMID:27363950

  18. Understanding the Nature of PHL 1811 Analogs

    NASA Astrophysics Data System (ADS)

    Brandt, W. N.

    2012-09-01

    A central tenet of X-ray astronomy is that luminous X-ray emission is a universal property of efficiently accreting supermassive black holes. However, we have recently studied a population of type 1 quasars that challenge this idea: PHL 1811 analogs. These objects are all X-ray weak and have exceptional UV emission-line properties. We propose snapshot observations of 10 bright radio-quiet PHL 1811 analogs that will more than double the sample of these objects with sensitive X-ray coverage. The improved sample size will better characterize the X-ray weakness of this population and allow correlation tests with emission-line properties. The improved photon statistics will aid joint spectral analyses investigating hints of hard X-ray spectra and X-ray absorption.

  19. Parabolic flight as a spaceflight analog.

    PubMed

    Shelhamer, Mark

    2016-06-15

    Ground-based analog facilities have had wide use in mimicking some of the features of spaceflight in a more-controlled and less-expensive manner. One such analog is parabolic flight, in which an aircraft flies repeated parabolic trajectories that provide short-duration periods of free fall (0 g) alternating with high-g pullout or recovery phases. Parabolic flight is unique in being able to provide true 0 g in a ground-based facility. Accordingly, it lends itself well to the investigation of specific areas of human spaceflight that can benefit from this capability, which predominantly includes neurovestibular effects, but also others such as human factors, locomotion, and medical procedures. Applications to research in artificial gravity and to effects likely to occur in upcoming commercial suborbital flights are also possible.

  20. Analog data transmission via fiber optics

    SciTech Connect

    Cisneros, E.L.; Burgueno, G.F.

    1986-10-01

    In the SLAC Linear Collider Detector (SLD), as in most high-energy particle detectors, the electromagnetic noise environment is the limiting factor in electronic readout performance. Front-end electronics are particulary susceptible to electromagnetic interference (EMI), and great care has been taken to minimize its effects. The transfer of preprocessed analog signals from the detector environs, to the remote digital processing electronics, by conventional means (via metal conductors), may ultimately limit the performance of the system. Because it is highly impervious to EMI and ground loops, a fiber-optic medium has been chosen for the transmission of these signals. This paper describes several fiber-optic transmission schemes which satisfy the requirements of the SLD analog data transmission.

  1. Submarine Analogs to Venusian Pancake Domes

    NASA Technical Reports Server (NTRS)

    Bridges, Nathan T.

    1995-01-01

    The morphology and dimensions of the large diameter, steep-sided, flat-topped "pancake domes" on Venus make them unlike any type of terrestrial subaerial volcano. Comparisons between images of Hawaiian seamounts and pancake domes show similarities in shapes and secondary features. The morphometry of pancake domes is closer to that of Pacific seamounts than subaerial lava domes. Considering both morphology and morphometry, seamounts seem a better analog to the pancake domes. The control of volatile exsolution by pressure on Venus and the seafloor can cause lavas to have similar viscosities and densities, although the latter will be counteracted by high buoyancy underwater. However, analogous effects of the Venusian and seafloor alone are probably not sufficient to produce similar volcanoes. Rather, Venusian lavas of various compositions may behave like basalt on the seafloor if appropriate rates and modes of extrusion and planetary thermal structure are also considered.

  2. Nonintentional analogical inference in text comprehension.

    PubMed

    Day, Samuel B; Gentner, Dedre

    2007-01-01

    We present findings suggesting that analogical inference processes can play a role in fluent comprehension and interpretation. Participants were found to use information from a prior relationally similar example in understanding the content of a later example, but they reported that they were not aware of having done so. These inference processes were sensitive to structural mappings between the two instances, ruling out explanations based solely on more general kinds of activation, such as priming. Reading speed measures were consistent with the possibility that these inferences had taken place during encoding of the target rather than during the later recognition test. These findings suggest that analogical mapping, though often viewed as an explicit deliberative process, can sometimes operate without intent or even awareness.

  3. Observing spin optodynamical analog of cavity optomechanics

    NASA Astrophysics Data System (ADS)

    Gerber, Justin; Kohler, Jonathan; Spethmann, Nicolas; Schreppler, Sydney; Stamper-Kurn, Dan

    2016-05-01

    Cavity Optomechanics has been realized in many diverse systems and led to many interesting results such as ponderomotive squeezing of light, beyond-SQL measurement sensitivity, and squeezing of mechanical oscillators. Optical cavities also allow sensitive measurements of the spin of an atomic ensemble. It has been proposed to utilize this sensitivity to realize an analog of optomechanics by measuring the precession of small excitations of a spin-oscillator around a transverse magnetic field. I will present our recent work in which we realize optomechanical analogs in our system such as cavity-assisted cooling and amplification and optical spring shifts. In addition, the presence of a high-energy `ground state' of the spin oscillator allows the realization of an effective negative mass oscillator which is demonstrated by an inverted sideband asymmetry. In our ongoing work we attempt to realize coherent quantum noise cancelation by coupling spin oscillation with mechanical oscillation.

  4. Variations in the GLA gene correlate with globotriaosylceramide and globotriaosylsphingosine analog levels in urine and plasma

    PubMed Central

    Ferreira, Susana; Auray-Blais, Christiane; Boutin, Michel; Lavoie, Pamela; Nunes, José Pedro; Martins, Elisabete; Garman, Scott; Oliveira, João Paulo

    2016-01-01

    Recent data have shown that lyso-Gb3, the deacylated derivative of globotriaosylceramide (Gb3), is possibly involved in the pathogenesis of Fabry disease (FD) and might be a clinically useful biomarker of its metabolic load. To test this hypothesis, we assayed Gb3 and lyso-Gb3 and related analogs in plasma and/or urine samples of 12 clinically well-characterized subjects carrying several different GLA variant alleles associated with a wide range of residual α-galactosidase A activities. Urinary Gb3 was measured by HPLC–MS/MS; plasma and urinary lyso-Gb3 and related analogs were measured by UPLC–MS/MS. Individual profiles of Gb3 and lyso-Gb3 and related analogs closely correlated with the phenotypic data for each subject, discerning the classical FD patient from the two patients carrying cardiac variants as well as these from all the others without FD. The lyso-Gb3 analog at m/z 836 was found at increased levels only in patients manifesting clinically severe heart disease, irrespective of the pathogenicity of the GLA variant they carried. This finding suggests that this lyso-Gb3 analog might be an earlier biomarker of progressive heart disease, non-specific of the FD cardiomyopathy. The possibility that urinary Gb3 is a specific marker of kidney involvement in FD deserves further study. PMID:26070511

  5. Biomedical sensor design using analog compressed sensing

    NASA Astrophysics Data System (ADS)

    Balouchestani, Mohammadreza; Krishnan, Sridhar

    2015-05-01

    The main drawback of current healthcare systems is the location-specific nature of the system due to the use of fixed/wired biomedical sensors. Since biomedical sensors are usually driven by a battery, power consumption is the most important factor determining the life of a biomedical sensor. They are also restricted by size, cost, and transmission capacity. Therefore, it is important to reduce the load of sampling by merging the sampling and compression steps to reduce the storage usage, transmission times, and power consumption in order to expand the current healthcare systems to Wireless Healthcare Systems (WHSs). In this work, we present an implementation of a low-power biomedical sensor using analog Compressed Sensing (CS) framework for sparse biomedical signals that addresses both the energy and telemetry bandwidth constraints of wearable and wireless Body-Area Networks (BANs). This architecture enables continuous data acquisition and compression of biomedical signals that are suitable for a variety of diagnostic and treatment purposes. At the transmitter side, an analog-CS framework is applied at the sensing step before Analog to Digital Converter (ADC) in order to generate the compressed version of the input analog bio-signal. At the receiver side, a reconstruction algorithm based on Restricted Isometry Property (RIP) condition is applied in order to reconstruct the original bio-signals form the compressed bio-signals with high probability and enough accuracy. We examine the proposed algorithm with healthy and neuropathy surface Electromyography (sEMG) signals. The proposed algorithm achieves a good level for Average Recognition Rate (ARR) at 93% and reconstruction accuracy at 98.9%. In addition, The proposed architecture reduces total computation time from 32 to 11.5 seconds at sampling-rate=29 % of Nyquist rate, Percentage Residual Difference (PRD)=26 %, Root Mean Squared Error (RMSE)=3 %.

  6. Analog Processor To Solve Optimization Problems

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A.; Eberhardt, Silvio P.; Thakoor, Anil P.

    1993-01-01

    Proposed analog processor solves "traveling-salesman" problem, considered paradigm of global-optimization problems involving routing or allocation of resources. Includes electronic neural network and auxiliary circuitry based partly on concepts described in "Neural-Network Processor Would Allocate Resources" (NPO-17781) and "Neural Network Solves 'Traveling-Salesman' Problem" (NPO-17807). Processor based on highly parallel computing solves problem in significantly less time.

  7. Analog optical computing primitives in silicon photonics.

    PubMed

    Jiang, Yunshan; DeVore, Peter T S; Jalali, Bahram

    2016-03-15

    Optical computing accelerators help alleviate bandwidth and power consumption bottlenecks in electronics. We show an approach to implementing logarithmic-type analog co-processors in silicon photonics and use it to perform the exponentiation operation and the recovery of a signal in the presence of multiplicative distortion. The function is realized by exploiting nonlinear-absorption-enhanced Raman amplification saturation in a silicon waveguide. PMID:26977687

  8. Survey of Evaluated Isobaric Analog States

    SciTech Connect

    MacCormick, M.

    2014-06-15

    Isobaric analog states (IAS) can be used to estimate the masses of members belonging to the same isospin multiplet. Experimental and estimated IAS have been used frequently within the Atomic Mass Evaluation (AME) in the past, but the associated set of evaluated masses have been published for the first time in AME2012 and NUBASE2012. In this paper the current trends of the isobaric multiplet mass equation (IMME) coefficients are shown. The T = 2 multiplet is used as a detailed illustration.

  9. Synthesis and biological evaluation of platensimycin analogs

    SciTech Connect

    Shen, Hong C.; Ding, Fa-Xiang; Singh, Sheo B.; Parthasarathy, Gopalakrishnan; Soisson, Stephen M.; Ha, Sookhee N.; Chen, Xun; Kodali, Srinivas; Wang, Jun; Dorso, Karen; Tata, James R.; Hammond, Milton L.; MacCoss, Malcolm; Colletti, Steven L.

    2009-07-23

    Platensimycin (1) displays antibacterial activity due to its inhibition of the elongation condensing enzyme (FabF), a novel mode of action that could potentially lead to a breakthrough in developing a new generation of antibiotics. The medicinal chemistry efforts were focused on the modification of the enone moiety of platensimycin and several analogs showed significant activity against FabF and possess antibacterial activity.

  10. The 2012 Moon and Mars Analog Mission

    NASA Technical Reports Server (NTRS)

    Graham, Lee

    2014-01-01

    The 2012 Moon and Mars Analog Mission Activities (MMAMA) scientific investigations were completed on Mauna Kea volcano in Hawaii in July 2012. The investigations were conducted on the southeast flank of the Mauna Kea volcano at an elevation of approximately 11,500 ft. This area is known as "Apollo Valley" and is in an adjacent valley to the Very Large Baseline Array dish antenna.

  11. Ophiolites as Analogs to Habitats on Mars

    NASA Technical Reports Server (NTRS)

    Schulte, M.; Blake, D. F.

    2003-01-01

    Ophiolite sequences that are located in northern and central California provide easily accessible areas that serve as good analogs for martian crustal rocks. The rock types found in a typical ophiolite sequence compare well with those found in the Mars meteorites, and those expected from spectrophotometric analysis. We have begun investigating and characterizing these sites in order to understand better the processes that may be responsible for the groundwater chemistry, mineralogy and biology of similar environments on Mars.

  12. Magnetic Analog Random-Access Memory

    NASA Technical Reports Server (NTRS)

    Katti, Romney R.; Wu, Jiin-Chuan; Stadler, Henry L.

    1991-01-01

    Proposed integrated, solid-state, analog random-access memory base on principle of magnetic writing and magnetoresistive reading. Current in writing conductor magnetizes storage layer. Remanent magnetization in storage layer penetrates readout layer and detected by magnetoresistive effect or Hall effect. Memory cells are part of integrated circuit including associated reading and writing transistors. Intended to provide high storage density and rapid access, nonvolatile, consumes little power, and relatively invulnerable to ionizing radiation.

  13. Synthetic analog computation in living cells.

    PubMed

    Daniel, Ramiz; Rubens, Jacob R; Sarpeshkar, Rahul; Lu, Timothy K

    2013-05-30

    A central goal of synthetic biology is to achieve multi-signal integration and processing in living cells for diagnostic, therapeutic and biotechnology applications. Digital logic has been used to build small-scale circuits, but other frameworks may be needed for efficient computation in the resource-limited environments of cells. Here we demonstrate that synthetic analog gene circuits can be engineered to execute sophisticated computational functions in living cells using just three transcription factors. Such synthetic analog gene circuits exploit feedback to implement logarithmically linear sensing, addition, ratiometric and power-law computations. The circuits exhibit Weber's law behaviour as in natural biological systems, operate over a wide dynamic range of up to four orders of magnitude and can be designed to have tunable transfer functions. Our circuits can be composed to implement higher-order functions that are well described by both intricate biochemical models and simple mathematical functions. By exploiting analog building-block functions that are already naturally present in cells, this approach efficiently implements arithmetic operations and complex functions in the logarithmic domain. Such circuits may lead to new applications for synthetic biology and biotechnology that require complex computations with limited parts, need wide-dynamic-range biosensing or would benefit from the fine control of gene expression.

  14. Clinical utility of insulin and insulin analogs

    PubMed Central

    Sanlioglu, Ahter D.; Altunbas, Hasan Ali; Balci, Mustafa Kemal; Griffith, Thomas S.; Sanlioglu, Salih

    2013-01-01

    Diabetes is a pandemic disease characterized by autoimmune, genetic and metabolic abnormalities. While insulin deficiency manifested as hyperglycemia is a common sequel of both Type-1 and Type-2 diabetes (T1DM and T2DM), it does not result from a single genetic defect—rather insulin deficiency results from the functional loss of pancreatic β cells due to multifactorial mechanisms. Since pancreatic β cells of patients with T1DM are destroyed by autoimmune reaction, these patients require daily insulin injections. Insulin resistance followed by β cell dysfunction and β cell loss is the characteristics of T2DM. Therefore, most patients with T2DM will require insulin treatment due to eventual loss of insulin secretion. Despite the evidence of early insulin treatment lowering macrovascular (coronary artery disease, peripheral arterial disease and stroke) and microvascular (diabetic nephropathy, neuropathy and retinopathy) complications of T2DM, controversy exists among physicians on how to initiate and intensify insulin therapy. The slow acting nature of regular human insulin makes its use ineffective in counteracting postprandial hyperglycemia. Instead, recombinant insulin analogs have been generated with a variable degree of specificity and action. Due to the metabolic variability among individuals, optimum blood glucose management is a formidable task to accomplish despite the presence of novel insulin analogs. In this article, we present a recent update on insulin analog structure and function with an overview of the evidence on the various insulin regimens clinically used to treat diabetes. PMID:23584214

  15. Backtracking quantum trajectories with analog feedback

    NASA Astrophysics Data System (ADS)

    de Lange*, G.; Ristè*, D.; Tiggelman, M. J.; Eichler, C.; Tornberg, L.; Johansson, G.; Wallraff, A.; Schouten, R. N.; Dicarlo, L.

    2014-03-01

    Circuit quantum electrodynamics offers a nearly ideal platform for the fundamental study of continuous quantum measurement. A nondemolition measurement of a superconducting qubit can be performed via homodyne detection of microwave transmission through a dispersively coupled cavity. By boosting the homodyne signal with a nearly noiseless phase-sensitive parametric amplifier, we experimentally show that a form of measurement backaction, consisting of stochastic quantum phase kicks on the measured qubit, is highly correlated with the fluctuations in the continuous homodyne record. We demonstrate a real-time analog feedback scheme that counteracts these phase kicks and thereby reduces measurement-induced dephasing. We develop a numerical optimization technique to overcome the bandwidth limitations of the amplification chain and provide a theoretical model for the optimization result. A quantum efficiency of 50% is extracted for the complete analog feedback loop. Finally, we discuss the integration of this analog feedback technique to improve performance in our recent demonstration of entanglement by dispersive parity measurement. *equal contribution. Research funded by NWO and the EU projects SOLID and SCALEQIT.

  16. Sensing Methods for Detecting Analog Television Signals

    NASA Astrophysics Data System (ADS)

    Rahman, Mohammad Azizur; Song, Chunyi; Harada, Hiroshi

    This paper introduces a unified method of spectrum sensing for all existing analog television (TV) signals including NTSC, PAL and SECAM. We propose a correlation based method (CBM) with a single reference signal for sensing any analog TV signals. In addition we also propose an improved energy detection method. The CBM approach has been implemented in a hardware prototype specially designed for participating in Singapore TV white space (WS) test trial conducted by Infocomm Development Authority (IDA) of the Singapore government. Analytical and simulation results of the CBM method will be presented in the paper, as well as hardware testing results for sensing various analog TV signals. Both AWGN and fading channels will be considered. It is shown that the theoretical results closely match with those from simulations. Sensing performance of the hardware prototype will also be presented in fading environment by using a fading simulator. We present performance of the proposed techniques in terms of probability of false alarm, probability of detection, sensing time etc. We also present a comparative study of the various techniques.

  17. Automated D/3 to Visio Analog Diagrams

    2000-08-10

    ADVAD1 reads an ASCII file containing the D/3 DCS MDL input for analog points for a D/3 continuous database. It uses the information in the files to create a series of Visio files representing the structure of each analog chain, one drawing per Visio file. The actual drawing function is performed by Visio (requires Visio version 4.5+). The user can configure the program to select which fields in the database are shown on the diagrammore » and how the information is to be presented. This gives a visual representation of the structure of the analog chains, showing selected fields in a consistent manner. Updating documentation can be done easily and the automated approach eliminates human error in the cadding process. The program can also create the drawings far faster than a human operator is capable, able to create approximately 270 typical diagrams in about 8 minutes on a Pentium II 400 MHz PC. The program allows for multiple option sets to be saved to provide different settings (i.e., different fields, different field presentations, and /or different diagram layouts) for various scenarios or facilities on one workstation. Option sets may be exported from the Windows registry to allow duplication of settings on another workstation.« less

  18. Targeting thyroid diseases with TSH receptor analogs.

    PubMed

    Galofré, Juan C; Chacón, Ana M; Latif, Rauf

    2013-12-01

    The thyroid-stimulating hormone (TSH) receptor (TSHR) is a major regulator of thyroid function and growth, and is the key antigen in several pathological conditions including hyperthyroidism, hypothyroidism, and thyroid tumors. Various effective treatment strategies are currently available for many of these clinical conditions such as antithyroid drugs or radioiodine therapy, but they are not devoid of side effects. In addition, treatment of complications of Graves' disease such as Graves' ophthalmopathy is often difficult and unsatisfactory using current methods. Recent advances in basic research on both in vitro and in vivo models have suggested that TSH analogs could be used for diagnosis and treatment of some of the thyroid diseases. The advent of high-throughput screening methods has resulted in a group of TSH analogs called small molecules, which have the potential to be developed as promising drugs. Small molecules are low molecular weight compounds with agonist, antagonist and, in some cases, inverse agonist activity on TSHR. This short review will focus on current advances in development of TSH analogs and their potential clinical applications. Rapid advances in this field may lead to the conduct of clinical trials of small molecules related to TSHR for the management of Graves' disease, thyroid cancer, and thyroid-related osteoporosis in the coming years.

  19. Periglacial and glacial analogs for Martian landforms

    NASA Technical Reports Server (NTRS)

    Rossbacher, Lisa A.

    1992-01-01

    The list of useful terrestrial analogs for Martian landforms has been expanded to include: features developed by desiccation processes; catastrophic flood features associated with boulder-sized materials; and sorted ground developed at a density boundary. Quantitative analytical techniques developed for physical geography have been adapted and applied to planetary studies, including: quantification of the patterns of polygonally fractured ground to describe pattern randomness independent of pattern size, with possible correlation to the mechanism of origin and quantification of the relative area of a geomorphic feature or region in comparison to planetary scale. Information about Martian geomorphology studied in this project was presented at professional meetings world-wide, at seven colleges and universities, in two interactive televised courses, and as part of two books. Overall, this project has expanded the understanding of the range of terrestrial analogs for Martian landforms, including identifying several new analogs. The processes that created these terrestrial features are characterized by both cold temperatures and low humidity, and therefore both freeze-thaw and desiccation processes are important. All these results support the conclusion that water has played a significant role in the geomorphic history of Mars.

  20. Scientific Analogies and Their Use in Teaching Science

    NASA Astrophysics Data System (ADS)

    Kipnis, Nahum

    Analogy in science knew its successes and failures, as illustrated by examples from the eighteenth-century physics. At times, some scientists abstained from using a certain analogy on the ground that it had not yet been demonstrated. Several false discoveries in the 18th and early 19th centuries appeared to support their caution. It is now clear that such a position reflected a methodological confusion that resulted from a failure to distinguish between particular and general analogies. Considering analogy as a hierarchical structure provides a new insight into "testing an analogy". While warning science teachers of dangers associated with use of analogy, historical cases and their analysis provided here may encourage them to use analogy more extensively while avoiding misconceptions. An argument is made that the history of science may be a better guide than philosophy of science and cognitive psychology when it concerns the role of analogy in science and in teaching science for understanding.

  1. [Relationship between chemical structure and sweetness. XIV. Analogs of aspartame].

    PubMed

    De Nardo, M

    1977-07-01

    Several analogs structurally related to aspartame were prepared in order to establish if chemical modifications of the molecule might improve sweetness. None of these analogs exhibited any sweet taste; on the contrary in most cases they were bitter.

  2. CAPE Analogs Induce Growth Arrest and Apoptosis in Breast Cancer Cells.

    PubMed

    Beauregard, Annie-Pier; Harquail, Jason; Lassalle-Claux, Grégoire; Belbraouet, Mehdi; Jean-Francois, Jacques; Touaibia, Mohamed; Robichaud, Gilles A

    2015-01-01

    Breast cancer is the second leading cause of death amongst women worldwide. As a result, many have turned their attention to new alternative approaches to treat this disease. Caffeic acid phenylethyl ester (CAPE), a well-known active compound from bee propolis, has been previously identified as a strong antioxidant, anti-inflammatory, antiviral and anticancer molecule. In fact, CAPE is well documented as inducing cell death by inhibiting NFκB and by inducing pro-apoptotic pathways (i.e., p53). With the objective of developing stronger anticancer compounds, we studied 18 recently described CAPE derivatives for their ability to induce apoptosis in breast cancer cell lines. Five of the said compounds, including CAPE, were selected and subsequently characterised for their anticancer mechanism of action. We validated that CAPE is a potent inducer of caspase-dependent apoptosis. Interestingly, some newly synthesized CAPE derivatives also showed greater cell death activity than the lead CAPE structure. Similarly to CAPE, analog compounds elicited p53 activation. Interestingly, one compound in particular, analog 10, induced apoptosis in a p53-mutated cell line. These results suggest that our new CAPE analog compounds may display the capacity to induce breast cancer apoptosis in a p53-dependent and/or independent manner. These CAPE analogs could thus provide new therapeutic approaches for patients with varying genotypic signatures (such as p53 mutations) in a more specific and targeted fashion. PMID:26184141

  3. Comparison of the activity and distribution of analog II and related compounds in the mouse and rat

    SciTech Connect

    Pento, J.T.; Koenig, K.K.; Magarian, R.A.; Shridhar, R.; Griffin, M.

    1986-03-01

    The authors have reported that 1,1-dichloro-Cis-2,3-diphenylcyclopropane (Analog II) is antiestrogenic in the mouse and inhibits the initiation and promotion of DMBA-induced tumors in the rat. Recently the authors have synthesized related cyclopropyl derivative of stilbene and stilbenediol. The object of the present study was to compare the activity of these compounds in the mouse and rat. Estrogenic and antiestrogenic activity of each compound was determined using the 3-day uterotropic assay and uterine histology in immature female Swiss Webster mice and Sprague-Dawley rats. (/sup 3/H)-Analog II was used in the tissue distribution studies. It was found that whereas Analog II was antiestrogenic in the mouse, this compound and related cis-stilbene analogs produced no antiestrogenic activity in the rat. However, trans-stilbenediol derivatives were estrogenic in both the mouse and rat with relatively equivalent activity in both species. In the tissue distribution study (/sup 3/H)-Analog II was found to be specifically concentrated in uterine tissue of the mouse but not the rat. This observation may explain, in part, the difference in antiestrogenic activity of Analog II between these two rodent species.

  4. Interactive Optical Disc Systems: Part 1: Analog Storage.

    ERIC Educational Resources Information Center

    Hessler, David W.

    1984-01-01

    Details distinction between digital and analog data, advantages of analog storage, and optical disc use to store analog data. Configuration and potential of three levels of laser disc systems are explained. Selection of display devices for use with laser disc systems and accessing audio data are addressed. (Continued in next issue.) (EJS)

  5. Using Analogies as an Experiential Learning Technique in Multicultural Education

    ERIC Educational Resources Information Center

    Suthakaran, V.; Filsinger, Keri; White, Brittany

    2013-01-01

    In this article the authors specifically address the use of narratives in the form of analogies as an experiential learning activity. The use of analogies as an experiential learning tool in multicultural education can be helpful in a number of ways. Analogies provide an alternative tool for processing multicultural topics with students who have…

  6. Modern Communication: Exploring Physiological Transmission through Tech-Savvy Analogies

    ERIC Educational Resources Information Center

    Hollabaugh, Christopher R.; Milanick, Mark A.

    2014-01-01

    Analogies are often helpful for students to grasp key physiological concepts; sometimes the technical jargon makes the concept seem more complex than it actually is. In this article the authors provide several analogies for information transfer processes that sometimes confuse students. For an analogy to be useful, of course, it needs to be…

  7. Analogies in Medicine: Valuable for Learning, Reasoning, Remembering and Naming

    ERIC Educational Resources Information Center

    Pena, Gil Patrus; Andrade-Filho, Jose de Souza

    2010-01-01

    Analogies are important tools in human reasoning and learning, for resolving problems and providing arguments, and are extensively used in medicine. Analogy and similarity involve a structural alignment or mapping between domains. This cognitive mechanism can be used to make inferences and learn new abstractions. Through analogies, we try to…

  8. Investigating and Theorizing Discourse during Analogy Writing in Chemistry

    ERIC Educational Resources Information Center

    Bellocchi, Alberto; Ritchie, Stephen M.

    2011-01-01

    Explanations of the role of analogies in learning science at a cognitive level are made in terms of creating bridges between new information and students' prior knowledge. In this empirical study of learning with analogies in an 11th grade chemistry class, we explore an alternative explanation at the "social" level where analogy shapes classroom…

  9. Anti-inflammatory effect of thalidomide dithiocarbamate and dithioate analogs.

    PubMed

    Talaat, Roba; El-Sayed, Waheba; Agwa, Hussein S; Gamal-Eldeen, Amira M; Moawia, Shaden; Zahran, Magdy A H

    2015-08-01

    Thalidomide has anti-inflammatory, immunomodulatory, and anti-angiogenic properties. It has been used to treat a variety of cancers and autoimmune diseases. This study aimed to characterize anti-inflammatory activities of novel thalidomide analogs by exploring their effects on splenocytes proliferation and macrophage functions and their antioxidant activity. MTT assay was used to assess the cytotoxic effect of thalidomide analogs against splenocytes. Tumor necrosis factor (TNF-α) and nuclear factor kappa B (NF-κB-P65) were determined by enzyme-linked immunosorbent assay (ELISA). Nitric oxide (NO) was estimated by colorimetric assay. Antioxidant activity was examined by ORAC assay. Our results demonstrated that thalidomide dithioate analog 2 and thalidomide dithiocarbamate analog 4 produced a slight increase in splenocyte proliferation compared with thalidomide. Thalidomide dithiocarbamate analog 1 is a potent inhibitor of TNF-α production, whereas thalidomide dithiocarbamate analog 5 is a potent inhibitor of both TNF-α and NO. Analog 2 has a pronounced inhibitory effect on NF-κB-P65 production level. All thalidomide analogs showed prooxidant activity against hydroxyl (OH) radical. Analog 1 and thalidomide dithioate analog 3 have prooxidant activity against peroxyl (ROO) radical in relation to thalidomide. On the other hand, analog 4 has a potent scavenging capacity against peroxyl (ROO) radical compared with thalidomide. Taken together, the results of this study suggest that thalidomide analogs might have valuable anti-inflammatory activities with more pronounced effect than thalidomide itself.

  10. Can Pupils Use Taught Analogies for Electric Current?

    ERIC Educational Resources Information Center

    Black, David; Solomon, Joan

    1987-01-01

    Discusses the use of analogies and models for teaching about electric current. Reports on a study in which one group of students used analogies to learn about electric current and one did not. Results indicate that, in this case, analogies did not play a significant role in student understanding. (TW)

  11. Functional DNA: Teaching Infinite Series through Genetic Analogy

    ERIC Educational Resources Information Center

    Kowalski, R. Travis

    2011-01-01

    This article presents an extended analogy that connects infinite sequences and series to the science of genetics, by identifying power series as "DNA for a function." This analogy allows standard topics such as convergence tests or Taylor approximations to be recast in a "forensic" light as mathematical analogs of genetic concepts such as DNA…

  12. Analogical Instruction in Statistics: Implications for Social Work Educators

    ERIC Educational Resources Information Center

    Thomas, Leela

    2008-01-01

    This paper examines the use of analogies in statistics instruction. Much has been written about the difficulty social work students have with statistics. To address this concern, Glisson and Fischer (1987) called for the use of analogies. Understanding of analogical problem solving has surged in the last few decades with the integration of…

  13. Using Analogical Reasoning to Deal with "Deep" Misconceptions in Physics.

    ERIC Educational Resources Information Center

    Clement, John; Brown, David

    In this paper examples of the role of analogical reasoning in expert problem solving are presented. These are intended to show that using an analogy can change an expert's understanding of a problem situation by changing the conceptual model he or she uses to think about the situation. This suggests that using a good analogy may allow students to…

  14. When Reasoning Modifies Memory: Schematic Assimilation Triggered by Analogical Mapping

    ERIC Educational Resources Information Center

    Vendetti, Michael S.; Wu, Aaron; Rowshanshad, Ebi; Knowlton, Barbara J.; Holyoak, Keith J.

    2014-01-01

    Analogical mapping highlights shared relations that link 2 situations, potentially at the expense of information that does not fit the dominant pattern of correspondences. To investigate whether analogical mapping can alter subsequent recognition memory for features of a source analog, we performed 2 experiments with 4-term proportional analogies…

  15. Spatial similarity and transferability of analog dates for precipitation downscaling over France

    NASA Astrophysics Data System (ADS)

    Chardon, Jérémy; Hingray, Benoit; Favre, Anne-Catherine; Autin, Philémon; Gailhard, Joël; Zin, Isabella; Obled, Charles

    2014-05-01

    High-resolution weather scenarios generated for climate change impact studies from the output of climate models have to be spatially coherent. Analog Models (AMs) have a high potential to generate such scenarios. For each prediction day, they use as scenario the weather observed for days in a historical archive that are analog according to different predictors. When a same 'analog date' is chosen for a prediction at several sites, the spatial coherency is automatically fulfilled. The optimal predictors and next the optimal analog dates are however expected to depend on the location for which the prediction has to be made. In this study, a set of 8,981 locally AMs - specifically optimized for the probabilistic prediction of 8,981 local precipitation 'stations' over France - is used to explore the two following questions: How does the domain-optimized AM perform for precipitation prediction at another location if the analogy domain used to identify the analog dates (in terms of spatial shape of 1000 and 500 hPa geopotential fields) is optimized to predict precipitation at a given location (question of transferability)? To what extent are the analog dates derived from a first AM domain-optimized for a given location similar to those of a second AM domain-optimized for a second location (question of similarity)? The mean similarity level of analog dates obtained from two different AMs is assessed with the percentage of issued predictions for which the number of identical analog dates is larger to a given percentage threshold. The spatial transferability is assessed with the loss of prediction performance - expressed by the Continuous Ranked Probability Skill Score (CRPSS) - when the transposed AM is used instead of the locally domain-optimized one. In our case, the mean similarity level is very low excepted when the two locations are very close. The spatial transferability of the optimal analog dates obtained for a given location is conversely very wide: when they are

  16. Inviting Argument by Analogy: Analogical-Mapping-Based Comparison Activities as a Scaffold for Small-Group Argumentation

    ERIC Educational Resources Information Center

    Emig, Brandon R.; McDonald, Scott; Zembal-Saul, Carla; Strauss, Susan G.

    2014-01-01

    This study invited small groups to make several arguments by analogy about simple machines. Groups were first provided training on analogical (structure) mapping and were then invited to use analogical mapping as a scaffold to make arguments. In making these arguments, groups were asked to consider three simple machines: two machines that they had…

  17. SSERVI Analog Regolith Simulant Testbed Facility

    NASA Astrophysics Data System (ADS)

    Minafra, Joseph; Schmidt, Gregory; Bailey, Brad; Gibbs, Kristina

    2016-10-01

    The Solar System Exploration Research Virtual Institute (SSERVI) at NASA's Ames Research Center in California's Silicon Valley was founded in 2013 to act as a virtual institute that provides interdisciplinary research centered on the goals of its supporting directorates: NASA Science Mission Directorate (SMD) and the Human Exploration & Operations Mission Directorate (HEOMD).Primary research goals of the Institute revolve around the integration of science and exploration to gain knowledge required for the future of human space exploration beyond low Earth orbit. SSERVI intends to leverage existing JSC1A regolith simulant resources into the creation of a regolith simulant testbed facility. The purpose of this testbed concept is to provide the planetary exploration community with a readily available capability to test hardware and conduct research in a large simulant environment.SSERVI's goals include supporting planetary researchers within NASA, other government agencies; private sector and hardware developers; competitors in focused prize design competitions; and academic sector researchers.SSERVI provides opportunities for research scientists and engineers to study the effects of regolith analog testbed research in the planetary exploration field. This capability is essential to help to understand the basic effects of continued long-term exposure to a simulated analog test environment.The current facility houses approximately eight tons of JSC-1A lunar regolith simulant in a test bin consisting of a 4 meter by 4 meter area, including dust mitigation and safety oversight.Facility hardware and environment testing scenarios could include, Lunar surface mobility, Dust exposure and mitigation, Regolith handling and excavation, Solar-like illumination, Lunar surface compaction profile, Lofted dust, Mechanical properties of lunar regolith, Surface features (i.e. grades and rocks)Numerous benefits vary from easy access to a controlled analog regolith simulant testbed, and

  18. Starch columns: Analog model for basalt columns

    NASA Astrophysics Data System (ADS)

    Müller, Gerhard

    1998-07-01

    Desiccation of starch-water mixtures produces tensile-crack patterns which appear to be interesting, but largely unknown study objects for fracture mechanics, structural geology, and volcanology. This paper concentrates on columnar jointing and on columns in starch. Starch columns have polygonal cross sections and are very similar to basalt columns. They are produced by lamp drying starch specimens with dimensions of several centimeters and have diameters in the millimeter range. The columns develop behind a crack front which propagates from the surface into the interior. The experiments, supported by X ray tomograms, show that polygonal regularity of the crack pattern is not present at the surface but develops during penetration. This transition is steered by a minimum-fracture-energy principle. The analogy between basalt cooling and starch desiccation is far reaching: water concentration in starch is analogous to temperature in basalt, both quantities obey diffusion equations, water loss is equivalent to heat loss, the resulting contraction stresses have similar dependences on depth and time, and in both cases the material strength is exceeded. The starch experiments show that column diameters are controlled by the depth gradient of water concentration at the crack front. High (low) gradients are connected with thin (thick) columns. By analogy, a similar relation with the temperature gradient exists for basalt columns. The (normalized) starch gradients are about 3 orders of magnitude larger than the (normalized) gradients in basalt. This explains why starch columns are much thinner than basalt columns. The gradients are so different, because the crack front speeds differ by a factor of about 10: after 3 days the speed is about 10 mm/d in starch but about 100 mm/d in basalt [Peck, 1978]. The speed difference, in turn, results from the difference of the diffusion constants: the hydraulic diffusivity of starch is 2 orders of magnitude lower than the thermal

  19. Mars-Analog Evaporite Experiment: Initial Results

    NASA Technical Reports Server (NTRS)

    Moore, J. M.; Bullock, M. A.; Sharp, T.G.; Quinn, R.

    2005-01-01

    This research is part of a multiyear experimental investigation to understand the nature and evolution brines and evaporates on Mars. The spectacular discoveries of the MER rovers, particularly those of Opportunity at Meridiani, both illustrate the relevance, as well as guide the future direction, of this work. Here we report the initial results from our just-completed and tested evaporites apparatus, using a synthetic brine analog to our brine experiment simulating a modern Mars environment in which the brine was subjected to rapid evaporation under modern Martian conditions. Additional information is included in the original extended abstract.

  20. Analog synthesized fast-variable linear load

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    1991-01-01

    A several kilowatt power level, fast-variable linear resistor was synthesized by using analog components to control the conductance of power MOSFETs. Risetimes observed have been as short as 500 ns with respect to the control signal and 1 to 2 microseconds with respect to the power source voltage. A variant configuration of this load that dissipates a constant power set by a control signal is indicated. Replacement of the MOSFETs by static induction transistors (SITs) to increase power handling, speed and radiation hardness is discussed.

  1. Analog synthesized fast-variable linear load

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    1991-01-01

    A several-kilowatt power level, fast-variable linear resistor has been synthesized by using analog components to control the conductance of power MOSFETs. Risetimes observed have been as short as 500 ns with respect to the control signal and 1 to 2 microsec with respect to the power source voltage. A variant configuration of this load that dissipates a constant power set by a control signal is indicated. Replacement of the MOSFETs by static induction transistors to increase power handling, speed, and radiation hardness is discussed.

  2. Soviet Space Stations as Analogs, Second Edition

    NASA Technical Reports Server (NTRS)

    Bluth, B. J.; Helppie, Martha

    1986-01-01

    The available literature that discusses the various aspects of the Soviet Salyut 6 and Salyut 7 space staions are examined as related to human productivity. The methodology for this analog was a search of unclassified literature. Additional information was obtained in interviews with the cosmonauts and some Soviet space personnel. Topics include: general layout and design of the spacecraft system; cosmonauts role in maintenance and repair; general layout and design of the Mir complex; effects of the environment on personnel; information and computer systems; organization systems; personality systems; and physical conditin of the cosmonaut.

  3. ANALOG QUANTUM NEURON FOR FUNCTIONS APPROXIMATION

    SciTech Connect

    A. EZHOV; A. KHROMOV; G. BERMAN

    2001-05-01

    We describe a system able to perform universal stochastic approximations of continuous multivariable functions in both neuron-like and quantum manner. The implementation of this model in the form of multi-barrier multiple-silt system has been earlier proposed. For the simplified waveguide variant of this model it is proved, that the system can approximate any continuous function of many variables. This theorem is also applied to the 2-input quantum neural model analogical to the schemes developed for quantum control.

  4. Pyrrolidine nucleotide analogs with a tunable conformation

    PubMed Central

    Poštová Slavětínská, Lenka; Rejman, Dominik

    2014-01-01

    Summary Conformational preferences of the pyrrolidine ring in nucleotide analogs 7–14 were investigated by means of NMR and molecular modeling. The effect of the relative configuration of hydroxy and nucleobase substituents as well as the effect of the alkylation or acylation of the pyrrolidine nitrogen atom on the conformation of the pyrrolidine ring were studied. The results of a conformational analysis show that the alkylation/acylation can be effectively used for tuning the pyrrolidine conformation over the whole pseudorotation cycle. PMID:25246956

  5. Scalable analog wavefront sensor with subpixel resolution

    NASA Astrophysics Data System (ADS)

    Wilcox, Michael

    2006-06-01

    Standard Shack-Hartman wavefront sensors use a CCD element to sample position and distortion of a target or guide star. Digital sampling of the element and transfer to a memory space for subsequent computation adds significant temporal delay, thus, limiting the spatial frequency and scalability of the system as a wavefront sensor. A new approach to sampling uses information processing principles in an insect compound eye. Analog circuitry eliminates digital sampling and extends the useful range of the system to control a deformable mirror and make a faster, more capable wavefront sensor.

  6. Solid-state-based analog of optomechanics

    DOE PAGESBeta

    Naumann, Nicolas L.; Droenner, Leon; Carmele, Alexander; Chow, Weng W.; Kabuss, Julia

    2016-06-21

    In this study, we investigate a semiconductor quantum dot as a microscopic analog of a basic optomechanical setup. We show that optomechanical features can be reproduced by the solid-state platform, arising from parallels of the underlying interaction processes, which in the optomechanical case is the radiation pressure coupling and in the semiconductor case the electron–phonon coupling. We discuss bistabilities, lasing, and phonon damping, and recover the same qualitative behaviors for the semiconductor and the optomechanical cases expected for low driving strengths. However, in contrast to the optomechanical case, distinct signatures of higher order processes arise in the semiconductor model.

  7. Analog/Digital System for Germanium Thermometer

    NASA Technical Reports Server (NTRS)

    Woodhouse, Christopher

    1988-01-01

    Electronic system containing analog and digital circuits makes high-precision, four-wire measurements of resistance of each germanium resistance thermometer (GRT) in array of devices, using alternating current (ac) of 1 micro-A. At end measurement interval, contents of negative register subtracted from positive one, resulting in very-narrow-band synchronous demodulation of carrier wave and suppression of out-of-band noise. Microprocessor free to perform other duties after measurement complete. Useful in noisy terrestrial environments encountered in factories.

  8. New Verapamil Analogs Inhibit Intracellular Mycobacteria without Affecting the Functions of Mycobacterium-Specific T Cells

    PubMed Central

    Ruminiski, Peter G.; Kumar, Malkeet; Singh, Kawaljit; Hamzabegovic, Fahreta; Hoft, Daniel F.; Eickhoff, Christopher S.; Selimovic, Asmir; Campbell, Mary; Chibale, Kelly

    2015-01-01

    There is a growing interest in repurposing mycobacterial efflux pump inhibitors, such as verapamil, for tuberculosis (TB) treatment. To aid in the design of better analogs, we studied the effects of verapamil on macrophages and Mycobacterium tuberculosis-specific T cells. Macrophage activation was evaluated by measuring levels of nitric oxide, tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), and gamma interferon (IFN-γ). Since verapamil is a known autophagy inducer, the roles of autophagy induction in the antimycobacterial activities of verapamil and norverapamil were studied using bone marrow-derived macrophages from ATG5flox/flox (control) and ATG5flox/flox Lyz-Cre mice. Our results showed that despite the well-recognized effects of verapamil on calcium channels and autophagy, its action on intracellular M. tuberculosis does not involve macrophage activation or autophagy induction. Next, the effects of verapamil and norverapamil on M. tuberculosis-specific T cells were assessed using flow cytometry following the stimulation of peripheral blood mononuclear cells from TB-skin-test-positive donors with M. tuberculosis whole-cell lysate for 7 days in the presence or absence of drugs. We found that verapamil and norverapamil inhibit the expansion of M. tuberculosis-specific T cells. Additionally, three new verapamil analogs were found to inhibit intracellular Mycobacterium bovis BCG, and one of the three analogs (KSV21) inhibited intracellular M. tuberculosis replication at concentrations that did not inhibit M. tuberculosis-specific T cell expansion. KSV21 also inhibited mycobacterial efflux pumps to the same degree as verapamil. More interestingly, the new analog enhances the inhibitory activities of isoniazid and rifampin on intracellular M. tuberculosis. In conclusion, KSV21 is a promising verapamil analog on which to base structure-activity relationship studies aimed at identifying more effective analogs. PMID:26643325

  9. Digital and Analog Gene Circuits for Biotechnology

    PubMed Central

    Roquet, Nathaniel; Lu, Timothy K.

    2014-01-01

    Biotechnology offers the promise of valuable chemical production via microbial processing of renewable and inexpensive substrates. Thus far, static metabolic engineering strategies have enabled this field to advance industrial applications. However, the industrial scaling of statically engineered microbes inevitably creates inefficiencies due to variable conditions present in large-scale microbial cultures. Synthetic gene circuits that dynamically sense and regulate different molecules can resolve this issue by enabling cells to continuously adapt to variable conditions. These circuits also have the potential to enable next-generation production programs capable of autonomous transitioning between steps in a bioprocess. Here, we review the design and application of two main classes of dynamic gene circuits, digital and analog, for biotechnology. Within the context of these classes, we also discuss the potential benefits of digital-analog interconversion, memory, and multi-signal integration. Though synthetic gene circuits have largely been applied for cellular computation to date, we envision that utilizing them in biotechnology will enhance the efficiency and scope of biochemical production with living cells. PMID:24677719

  10. AFEII Analog Front End Board Design Specifications

    SciTech Connect

    Rubinov, Paul; /Fermilab

    2005-04-01

    This document describes the design of the 2nd iteration of the Analog Front End Board (AFEII), which has the function of receiving charge signals from the Central Fiber Tracker (CFT) and providing digital hit pattern and charge amplitude information from those charge signals. This second iteration is intended to address limitations of the current AFE (referred to as AFEI in this document). These limitations become increasingly deleterious to the performance of the Central Fiber Tracker as instantaneous luminosity increases. The limitations are inherent in the design of the key front end chips on the AFEI board (the SVXIIe and the SIFT) and the architecture of the board itself. The key limitations of the AFEI are: (1) SVX saturation; (2) Discriminator to analog readout cross talk; (3) Tick to tick pedestal variation; and (4) Channel to channel pedestal variation. The new version of the AFE board, AFEII, addresses these limitations by use of a new chip, the TriP-t and by architectural changes, while retaining the well understood and desirable features of the AFEI board.

  11. Menaquinone analogs inhibit growth of bacterial pathogens.

    PubMed

    Schlievert, Patrick M; Merriman, Joseph A; Salgado-Pabón, Wilmara; Mueller, Elizabeth A; Spaulding, Adam R; Vu, Bao G; Chuang-Smith, Olivia N; Kohler, Petra L; Kirby, John R

    2013-11-01

    Gram-positive bacteria cause serious human illnesses through combinations of cell surface and secreted virulence factors. We initiated studies with four of these organisms to develop novel topical antibacterial agents that interfere with growth and exotoxin production, focusing on menaquinone analogs. Menadione, 1,4-naphthoquinone, and coenzymes Q1 to Q3 but not menaquinone, phylloquinone, or coenzyme Q10 inhibited the growth and to a greater extent exotoxin production of Staphylococcus aureus, Bacillus anthracis, Streptococcus pyogenes, and Streptococcus agalactiae at concentrations of 10 to 200 μg/ml. Coenzyme Q1 reduced the ability of S. aureus to cause toxic shock syndrome in a rabbit model, inhibited the growth of four Gram-negative bacteria, and synergized with another antimicrobial agent, glycerol monolaurate, to inhibit S. aureus growth. The staphylococcal two-component system SrrA/B was shown to be an antibacterial target of coenzyme Q1. We hypothesize that menaquinone analogs both induce toxic reactive oxygen species and affect bacterial plasma membranes and biosynthetic machinery to interfere with two-component systems, respiration, and macromolecular synthesis. These compounds represent a novel class of potential topical therapeutic agents.

  12. Antarctic analog for dilational bands on Europa

    NASA Astrophysics Data System (ADS)

    Hurford, T. A.; Brunt, K. M.

    2014-09-01

    Europa's surface shows signs of extension, which is revealed as lithospheric dilation expressed along ridges, dilational bands and ridged bands. Ridges, the most common tectonic feature on Europa, comprise a central crack flanked by two raised banks a few hundred meters high on each side. Together these three classes may represent a continuum of formation. In Tufts' Dilational Model ridge formation is dominated by daily tidal cycling of a crack, which can be superimposed with regional secular dilation. The two sources of dilation can combine to form the various band morphologies observed. New GPS data along a rift on the Ross Ice Shelf, Antarctica is a suitable Earth analog to test the framework of Tufts' Dilational Model. As predicted by Tufts' Dilational Model, tensile failures in the Ross Ice Shelf exhibit secular dilation, upon which a tidal signal can be seen. From this analog we conclude that Tufts' Dilational Model for Europan ridges and bands may be credible and that the secular dilation is most likely from a regional source and not tidally driven.

  13. Triton's eruptions analogous to Comet Halley's?

    NASA Astrophysics Data System (ADS)

    Wallis, Max K.; Wickramasinghe, N. C.

    1992-11-01

    It is hypothesized that Triton's geysers are analogous to the remnant activity of Comet Halley, whose outbursts producing a particulate coma are persisting out beyond 12 AU Halley's outbursts are understood as resulting from inward freezing of a subsurface lake or sea that's maintained at greater than 10 m depth via metabolic energy release. Cracking of the ice due to thermal expansion forces generates sporadic emissions of H2O and other gases. Analogous activity on Triton is a manifestation of internal freezing of an interior sea under a km or so of ice. This sea at the present epoch is quite separate from the interior liquid ocean, expected to be maintained at greater than 100 km deep by radiogenic heating. The near-surface sea is maintained also by chemical or metabolic energy and sporadically emits gases and condensates through cracks induced during its freezing. Emissions through the ice cover on both comets and Triton would drive surface geology, thus enabling access to new nutrients and trace elements that may be vital for subterranean biology. Triton's biology would be a relic from its tidal heating phase, when the interior was liquid below a 1-2 km frozen lithosphere.

  14. C-Glycosyl Analogs of Oligosaccharides

    NASA Astrophysics Data System (ADS)

    Vauzeilles, Boris; Urban, Dominique; Doisneau, Gilles; Beau, Jean-Marie

    This chapter covers the synthesis of a large collection of "C-oligosaccharides ", synthetic analogs of naturally occurring oligosaccharides in which a carbon atom replaces the anomeric, interglycosidic oxygen atom. These non-natural constructs are stable to chemical and enzymatic degradation, and are primarily devised to probe carbohydrate-based biological processes. These mainly target carbohydrate-protein interactions such as the modulation of glycoenzyme (glycosylhydrolases and transferases) activities or the design of ligands for lectin Carbohydrate Recognition Domains. The discussion is based on the key carbon-carbon bond assembling steps on carbohydrate templates: ionic (anionic and cationic chemistries, sigmatropic rearrangements) or radical assemblage, and olefin metathesis. Synthetic schemes in which at least one of the monosaccharide units is constructed by total synthesis or by cyclization of acyclic chiral chains are presented separately in a "partial de novo synthesis" section. The review also provides comments, when they are known, on the conformational and binding properties of these synthetic analogs, as well as their biological behavior when tested.

  15. EF-G Activation by Phosphate Analogs.

    PubMed

    Salsi, Enea; Farah, Elie; Ermolenko, Dmitri N

    2016-05-22

    Elongation factor G (EF-G) is a universally conserved translational GTPase that promotes the translocation of tRNA and mRNA through the ribosome. EF-G binds to the ribosome in a GTP-bound form and subsequently catalyzes GTP hydrolysis. The contribution of the ribosome-stimulated GTP hydrolysis by EF-G to tRNA/mRNA translocation remains debated. Here, we show that while EF-G•GDP does not stably bind to the ribosome and induce translocation, EF-G•GDP in complex with phosphate group analogs BeF3(-) and AlF4(-) promotes the translocation of tRNA and mRNA. Furthermore, the rates of mRNA translocation induced by EF-G in the presence of GTP and a non-hydrolyzable analog of GTP, GDP•BeF3(-) are similar. Our results are consistent with the model suggesting that GTP hydrolysis is not directly coupled to mRNA/tRNA translocation. Hence, GTP binding is required to induce the activated, translocation-competent conformation of EF-G while GTP hydrolysis triggers EF-G release from the ribosome. PMID:27063503

  16. Palytoxin and Analogs: Biological and Ecological Effects

    PubMed Central

    Ramos, Vítor; Vasconcelos, Vítor

    2010-01-01

    Palytoxin (PTX) is a potent marine toxin that was originally found in soft corals from tropical areas of the Pacific Ocean. Soon after, its occurrence was observed in numerous other marine organisms from the same ecological region. More recently, several analogs of PTX were discovered, remarkably all from species of the dinoflagellate genus Ostreopsis. Since these dinoflagellates are also found in other tropical and even in temperate regions, the formerly unsuspected broad distribution of these toxins was revealed. Toxicological studies with these compounds shows repeatedly low LD50 values in different mammals, revealing an acute toxic effect on several organs, as demonstrated by different routes of exposure. Bioassays tested for some marine invertebrates and evidences from environmental populations exposed to the toxins also give indications of the high impact that these compounds may have on natural food webs. The recognition of its wide distribution coupled with the poisoning effects that these toxins can have on animals and especially on humans have concerned the scientific community. In this paper, we review the current knowledge on the effects of PTX and its analogs on different organisms, exposing the impact that these toxins may have in coastal ecosystems. PMID:20714422

  17. Endpoint distinctiveness facilitates analogical mapping in pigeons.

    PubMed

    Hagmann, Carl Erick; Cook, Robert G

    2015-03-01

    Analogical thinking necessitates mapping shared relations across two separate domains. We investigated whether pigeons could learn faster with ordinal mapping of relations across two physical dimensions (circle size & choice spatial position) relative to random mapping of these relations. Pigeons were trained to relate six circular samples of different sizes to horizontally positioned choice locations in a six alternative matching-to-sample task. Three pigeons were trained in a mapped condition in which circle size mapped directly onto choice spatial position. Three other pigeons were trained in a random condition in which the relations between size and choice position were arbitrarily assigned. The mapped group showed an advantage over the random group in acquiring this task. In a subsequent second phase, relations between the dimensions were ordinally reversed for the mapped group and re-randomized for the random group. There was no difference in how quickly matching accuracy re-emerged in the two groups, although the mapped group eventually performed more accurately. Analyses suggested this mapped advantage was likely due to endpoint distinctiveness and the benefits of proximity errors during choice responding rather than a conceptual or relational advantage attributable to the common or ordinal mapping of the two dimensions. This potential difficulty in mapping relations across dimensions may limit the pigeons' capacity for more advanced types of analogical reasoning. This article is part of a Special Issue entitled: Tribute to Tom Zentall.

  18. The gravitational analog of Faraday's induction law

    NASA Astrophysics Data System (ADS)

    Zile, Daniel; Overduin, James

    2015-04-01

    Michael Faraday, the discoverer of electromagnetic induction, was convinced that there must also be a gravitational analog of this law, and he carried out drop-tower experiments in 1849 to look for the electric current induced in a coil by changes in gravitational flux through the coil. This work, now little remembered, was in some ways the first investigation of what we would now call a unified-field theory. We revisit Faraday's experiments in the light of current knowledge and ask what might be learned if they were to be performed today. We then review the gravitational analog for Faraday's law that arises within the vector (or gravito-electromagnetic) approximation to Einstein's theory of general relativity in the weak-field, low-velocity limit. This law relates spinning masses and induced ``mass currents'' rather than spinning charges and electric currents, but is otherwise remarkably similar to its electromagnetic counterpart. The predicted effects are completely unobservable in everyday settings like those envisioned by Faraday, but are thought to be relevant in astrophysical contexts like the accretion disks around collapsed stars, thus bearing out Faraday's remarkable intuition. Undergraduate student.

  19. Digital and analog gene circuits for biotechnology.

    PubMed

    Roquet, Nathaniel; Lu, Timothy K

    2014-05-01

    Biotechnology offers the promise of valuable chemical production via microbial processing of renewable and inexpensive substrates. Thus far, static metabolic engineering strategies have enabled this field to advance industrial applications. However, the industrial scaling of statically engineered microbes inevitably creates inefficiencies due to variable conditions present in large-scale microbial cultures. Synthetic gene circuits that dynamically sense and regulate different molecules can resolve this issue by enabling cells to continuously adapt to variable conditions. These circuits also have the potential to enable next-generation production programs capable of autonomous transitioning between steps in a bioprocess. Here, we review the design and application of two main classes of dynamic gene circuits, digital and analog, for biotechnology. Within the context of these classes, we also discuss the potential benefits of digital-analog interconversion, memory, and multi-signal integration. Though synthetic gene circuits have largely been applied for cellular computation to date, we envision that utilizing them in biotechnology will enhance the efficiency and scope of biochemical production with living cells.

  20. Martian hillside gullies and icelandic analogs

    NASA Astrophysics Data System (ADS)

    Hartmann, William K.; Thorsteinsson, Thorsteinn; Sigurdsson, Freysteinn

    2003-04-01

    We report observations of Icelandic hillside gully systems that are near duplicates of gullies observed on high-latitude martian hillsides. The best Icelandic analogs involve basaltic talus slopes at the angle of repose, with gully formation by debris flows initiated by ground water saturation, and/or by drainage of water from upslope cliffs. We report not only the existence of Mars analog gullies, but also an erosional sequence of morphologic forms, found both on Mars and in Iceland. The observations support hypotheses calling for creation of martian gullies by aqueous processes. Issues remain whether the water in each case comes only from surficial sources, such as melting of ground ice or snow, or from underground sources such as aquifers that gain surface access in hillsides. Iceland has many examples of the former, but the latter mechanism is not ruled out. Our observations are consistent with the martian debris flow mechanism of F. Costard et al. (2001c, Science295, 110-113), except that classic debris flows begin at midslope more frequently than on Mars. From morphologic observations, we suggest that some martian hillside gully systems not only involve significant evolution by extended erosive activity, but gully formation may occur in episodes, and the time interval since the last episode is considerably less than the time interval needed to erase the gully through normal martian obliteration processes.

  1. Metastatic Insulinoma Managed with Radiolabeled Somatostatin Analog

    PubMed Central

    Costa, Ricardo; Bacchi, Carlos E.; Almeida Filho, Paulo

    2013-01-01

    Insulinoma is a rare pancreatic neuroendocrine tumor. Overproduction of insulin and associated hypoglycemia are hallmark features of this disease. Diagnosis can be made through demonstration of hypoglycemia and elevated plasma levels of insulin or C-Peptide. Metastatic disease can be detected through computerized tomography (CT) scans, magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT. Somatostatin receptor scintigraphy can be used not only to document metastatic disease but also as a predictive marker of the benefit from therapy with radiolabeled somatostatin analog. Unresectable metastatic insulinomas may present as a major therapeutic challenge for the treating physician. When feasible, resection is the mainstay of treatment. Prevention of hypoglycemia is a crucial goal of therapy for unresectable/metastatic tumors. Diazoxide, hydrochlorothiazide, glucagon, and intravenous glucose infusions have been used for glycemic control yielding temporary and inconsistent results. Sandostatin and its long-acting depot forms have occasionally been used in the treatment of Octreoscan-positive insulinomas. Herein, we report a case of metastatic insulinoma with very difficult glycemic control successfully treated with the radiolabeled somatostatin analog lutetium (177LU). PMID:24455330

  2. Antarctic Analog for Dilational Bands on Europa

    NASA Technical Reports Server (NTRS)

    Hurford, T. A.; Brunt, K. M.

    2014-01-01

    Europa's surface shows signs of extension, which is revealed as lithospheric dilation expressed along ridges, dilational bands and ridged bands. Ridges, the most common tectonic feature on Europa, comprise a central crack flanked by two raised banks a few hundred meters high on each side. Together these three classes may represent a continuum of formation. In Tufts' Dilational Model ridge formation is dominated by daily tidal cycling of a crack, which can be superimposed with regional secular dilation. The two sources of dilation can combine to form the various band morphologies observed. New GPS data along a rift on the Ross Ice Shelf, Antarctica is a suitable Earth analog to test the framework of Tufts' Dilational Model. As predicted by Tufts' Dilational Model, tensile failures in the Ross Ice Shelf exhibit secular dilation, upon which a tidal signal can be seen. From this analog we conclude that Tufts' Dilational Model for Europan ridges and bands may be credible and that the secular dilation is most likely from a regional source and not tidally driven.

  3. Operational Lessons Learned from NASA Analog Missions

    NASA Technical Reports Server (NTRS)

    Arnold, Larissa S.

    2010-01-01

    vehicle and system capabilities are required to support the activities? How will the crew and the Earth-based mission control team interact? During the initial phases of manned planetary exploration, one challenge in particular is virtually the same as during the Apollo program: How can scientific return be maximized during a relatively short surface mission? Today, NASA is investigating solutions to these challenges by conducting analog missions. These Earth-based missions possess characteristics that are analogous to missions on the Moon or Mars. These missions are excellent for testing operational concepts, and the design, configuration, and functionality of spacesuits, robots, rovers, and habitats. Analog mission crews test specific techniques and procedures for surface field geology, biological sample collection, and planetary protection. The process of actually working an analog mission reveals a myriad of small details, which either contribute to or impede efficient operations, many of which would never have been thought about otherwise. It also helps to define the suite of tools, containers, and other small equipment that surface explorers will use. This paper focuses on how analog missions have addressed selected operational considerations for future planetary missions.

  4. Experiments on Evolving Software Models of Analog Circuits

    NASA Technical Reports Server (NTRS)

    Lohn, Jason D.

    1999-01-01

    Analog circuits are of great importance in electronic system design since the world is fundamentally analog in nature. While the amount of digital design activity far outpaces that of analog design, most digital systems require analog modules for interfacing with the external world. It was recently estimated that approximately 60% of digital application- specific integrated circuit designs incorporated analog circuits. With challenging analog circuit design problems and few analog design engineers, there are economic reasons for automating the analog design process, especially time-to-market considerations. Techniques for analog circuit design automation began appearing about two decades ago. These methods incorporated heuristics [6], knowledge bases [1], simulated annealing [5], and other algorithms. Efforts using techniques from evolutionary computation began appearing over the last few years. These include the use of genetic algorithms to select electronic component values (for example, the resistance value of a resistor), to select circuit topologies, and to design amplifiers using a limited set of canned topologies [4]. A genetic programming-based analog circuit design system has been demonstrated in which the circuit sizes, component values, and the circuit topologies are determined automatically [3]. The genetic-algorithm systems typically represent circuit structures as vectors of parameters encoded in binary strings, while the genetic programming system manipulates tree data structures.

  5. Crystal structures of arginine kinase in complex with ADP, nitrate, and various phosphagen analogs.

    PubMed

    Clark, Shawn A; Davulcu, Omar; Chapman, Michael S

    2012-10-12

    Arginine kinase catalyzes the reversible transfer of a phosphoryl group between ATP and l-arginine and is a monomeric homolog of the human enzyme creatine kinase. Arginine and creatine kinases belongs to the phosphagen kinase family of enzymes, which consists of eight known members, each of which is specific for its own phosphagen. Here, the source of phosphagen specificity in arginine kinase is investigated through the use of phosphagen analogs. Crystal structures have been determined for Limulus polyphemus arginine kinase with one of four arginine analogs bound in a transition state analog complex: l-ornithine, l-citrulline, imino-l-ornithine, and d-arginine. In all complexes, the enzyme achieves a closed conformation very similar to that of the cognate transition state analog complex, but differences are observed in the configurations of bound ligands. Arginine kinase exhibits no detectable activity towards ornithine, citrulline, or imino-l-ornithine, and only trace activity towards d-arginine. The crystal structures presented here demonstrate that phosphagen specificity is derived neither from a lock-and-key mechanism nor a modulation of induced-fit conformational changes, but potentially from subtle distortions in bound substrate configurations. PMID:22995310

  6. Mosquitocidal properties of natural product compounds isolated from Chinese herbs and synthetic analogs of curcumin.

    PubMed

    Anstrom, David M; Zhou, Xia; Kalk, Cody N; Song, Baoan; Lan, Que

    2012-03-01

    Because of resistance to current insecticides and to environmental, health, and regulatory concerns, naturally occurring compounds and their derivatives are of increasing interest for the development of new insecticidal compounds against vectors of disease-causing pathogens. Fifty-eight compounds, either extracted and purified from plants native to China or synthetic analogs of curcumin, were evaluated for both their larvicidal activity against Aedes aegypti (L.) and their ability to inhibit binding of cholesterol to Ae. aegypti sterol carrier protein-2 in vitro. Of the compounds tested, curcumin analogs seem especially promising in that of 24 compounds tested five were inhibitors of Ae. aegypti sterol carrier protein-2 with EC50 values ranging from 0.65 to 62.87 microM, and three curcumin analogs exhibited larvicidal activity against fourth instar Ae. aegypti larvae with LC50 values ranging from 17.29 to 27.90 microM. Adding to the attractiveness of synthetic curcumin analogs is the relative ease of synthesizing a large diversity of compounds; only a small fraction of such diversity has been sampled in this study.

  7. A study on the application of two different acoustic analogies to experimental PIV data

    NASA Astrophysics Data System (ADS)

    Koschatzky, V.; Westerweel, J.; Boersma, B. J.

    2011-06-01

    The aim of the present study is to compare two different acoustic analogies applied to time-resolved particle image velocimetry (PIV) data for the prediction of the acoustic far-field generated by the flow over a rectangular cavity. We consider the model problem of sound radiating from an open, two-dimensional, shallow cavity with an aspect ratio of 2 at a Reynolds number of 3.0 × 104 (based on the cavity length). The study is carried out by simultaneous high-speed two-dimensional PIV and sound measurements. The instantaneous flow field is obtained from the PIV measurements. The emitted sound is then calculated using Curle's analogy and Vortex Sound Theory. To our knowledge, Vortex Sound Theory is used here for the first time in combination with time-resolved PIV data. The acoustic analogies are derived through rather different pathways, and the mathematical schemes used to solve the equations are sensitive in a different way to factors such as data resolution, noise level, and complexity of the geometry. Both methods indicate that the trailing edge of the cavity is the main sound source. The predictions of the acoustic field obtained by applying the two methods are analyzed and compared with the measured sound. For the presented case, the results show that both analogies estimate the overall sound pressure level quite well and that they give very similar results, both in total intensity and in the spectral distribution of the emitted sound.

  8. Anti-inflammatory effects of a triple-bond resveratrol analog: structure and function relationship.

    PubMed

    Antus, Csenge; Radnai, Balazs; Dombovari, Peter; Fonai, Fruzsina; Avar, Peter; Matyus, Peter; Racz, Boglarka; Sumegi, Balazs; Veres, Balazs

    2015-02-01

    Resveratrol is a polyphenol found in grapes and red wine, showing well-characterized anti-inflammatory and antiproliferative activities. In order to exceed resveratrol׳s biological effects and to reveal the structural determinants of the molecule׳s activity, numerous derivatives were synthesized recently. Most of these resveratrol analogs vary from the original molecule in the number, position or identity of the phenolic functional groups. Investigation of the analogs provided important data regarding structure-activity relationship of the molecule. With the exception of cis- and trans-resveratrol and the reduced form dihydroresveratrol, little is known about the molecular effects of the stilbene backbone. In the present study we investigated the anti-inflammatory properties of a new, triple-bond resveratrol analog, 3,4',5-trihydroxy-diphenylacetylene (TDPA) on lipopolysaccharide-stimulated RAW macrophages. We found that the analog had weaker antioxidant activity and stronger inhibitory effect on nuclear factor-kappaB activation, and on cyclooxygenase-2, tumor necrosis factor α and interleukin-6 production. It also prevented lipopolysaccharide-induced depolarization of the mitochondrial membrane. In contrast to resveratrol, TDPA increased the phosphorylation of c-Jun N-terminal and p38 mitogen activated protein kinases. In summary, we identified a novel compound with better anti-inflammatory properties than resveratrol. Our results contributed to a better understanding of the structural determinants of resveratrol׳s biological activities. PMID:25528327

  9. Mosquitocidal Properties of Natural Product Compounds Isolated From Chinese Herbs and Synthetic Analogs of Curcumin

    PubMed Central

    ANSTROM, DAVID M.; ZHOU, XIA; KALK, CODY N.; SONG, BAOAN; LAN, QUE

    2012-01-01

    Because of resistance to current insecticides and to environmental, health, and regulatory concerns, naturally occurring compounds and their derivatives are of increasing interest for the development of new insecticidal compounds against vectors of disease-causing pathogens. Fifty-eight compounds, either extracted and purified from plants native to China or synthetic analogs of curcumin, were evaluated for both their larvicidal activity against Aedes aegypti (L.) and their ability to inhibit binding of cholesterol to Ae. aegypti sterol carrier protein-2 in vitro. Of the compounds tested, curcumin analogs seem especially promising in that of 24 compounds tested five were inhibitors of Ae. aegyptisterol carrier protein-2 with EC50 values ranging from 0.65 to 62.87 μM, and three curcumin analogs exhibited larvicidal activity against fourth instar Ae. aegypti larvae with LC50 values ranging from 17.29 to 27.90 μM. Adding to the attractiveness of synthetic curcumin analogs is the relative ease of synthesizing a large diversity of compounds; only a small fraction of such diversity has been sampled in this study. PMID:22493854

  10. Comprehending speaker intent in rebuttal analogy use: the role of irony mapping, absurdity comparison and argumentative convention.

    PubMed

    Colston, H L

    2000-01-01

    Rebuttal analogies (e.g., "Politicians arguing over the renaming of an airport is like watering your petunias when your house is on fire") are commonly used as responses in verbal conflicts. The following study investigated the role that irony mapping, absurdity comparison, and argumentative convention play in interpreters' derivations of speaker's intentions in using rebuttal analogies. In general, these intentions are to demonstrate the unsoundness of the opposed proposition ("argument") and its advocate ("social attack"), (Whaley & Holloway, 1996). Three rebuttal analogy types were rated on argumentativeness and social attack in verbal conflict and nonverbal conflict scenarios. The results of six experiments on 120 participants found that analogies with ironic bases (e.g., "Doubling the defense budget in order to intimidate North Korea is like using a chainsaw to file your nails") were perceived as more of a social attack and as more argumentative than analogies with absurd (e.g., "... using ketchup to wax your car") and nonironic (e.g., "... using a nailfile to file your nails") bases. No difference was found between the two scenario types. Norming data confirmed equivalence of absurdity of ironic and absurd bases, and greater irony of ironic over absurd bases. The results thus implicate hearers' use of the ironic structure between bases and targets in the interpretation of rebuttal analogies rather than mere absurdity comparison or argumentative convention.

  11. Comprehending speaker intent in rebuttal analogy use: the role of irony mapping, absurdity comparison and argumentative convention.

    PubMed

    Colston, H L

    2000-01-01

    Rebuttal analogies (e.g., "Politicians arguing over the renaming of an airport is like watering your petunias when your house is on fire") are commonly used as responses in verbal conflicts. The following study investigated the role that irony mapping, absurdity comparison, and argumentative convention play in interpreters' derivations of speaker's intentions in using rebuttal analogies. In general, these intentions are to demonstrate the unsoundness of the opposed proposition ("argument") and its advocate ("social attack"), (Whaley & Holloway, 1996). Three rebuttal analogy types were rated on argumentativeness and social attack in verbal conflict and nonverbal conflict scenarios. The results of six experiments on 120 participants found that analogies with ironic bases (e.g., "Doubling the defense budget in order to intimidate North Korea is like using a chainsaw to file your nails") were perceived as more of a social attack and as more argumentative than analogies with absurd (e.g., "... using ketchup to wax your car") and nonironic (e.g., "... using a nailfile to file your nails") bases. No difference was found between the two scenario types. Norming data confirmed equivalence of absurdity of ironic and absurd bases, and greater irony of ironic over absurd bases. The results thus implicate hearers' use of the ironic structure between bases and targets in the interpretation of rebuttal analogies rather than mere absurdity comparison or argumentative convention. PMID:11419221

  12. Base-modified nucleosides: etheno derivatives

    NASA Astrophysics Data System (ADS)

    Jahnz-Wechmann, Zofia; Framski, Grzegorz; Januszczyk, Piotr; Boryski, Jerzy

    2016-04-01

    This review presents synthesis and chemistry of nucleoside analogs, possessing an additional fused, heterocyclic ring of the “etheno” type, such as 1,N6-ethenoadenosine, 1,N4-ethenocytidine, 1,N2-ethenoguanosine, and other related derivatives. Formation of ethenonucleosides, in the presence of α-halocarbonyl reagents and their mechanism, stability and degradation, reactions of substitution and transglycosylation, as well as their application in the nucleoside synthesis, have been described. Some of the discussed compounds may be applied as chemotherapeutic agents in antiviral and anticancer treatment, acting as pro-nucleosides of already known, biologically active nucleoside analogs..

  13. Base-Modified Nucleosides: Etheno Derivatives

    PubMed Central

    Jahnz-Wechmann, Zofia; Framski, Grzegorz R.; Januszczyk, Piotr A.; Boryski, Jerzy

    2016-01-01

    This review presents synthesis and chemistry of nucleoside analogs, possessing an additional fused, heterocyclic ring of the “etheno” type, such as 1,N6-ethenoadenosine, 1,N4-ethenocytidine, 1,N2-ethenoguanosine, and other related derivatives. Formation of ethenonucleosides, in the presence of α-halocarbonyl reagents and their mechanism, stability, and degradation, reactions of substitution and transglycosylation, as well as their application in the nucleoside synthesis, have been described. Some of the discussed compounds may be applied as chemotherapeutic agents in antiviral and anticancer treatment, acting as pro-nucleosides of already known, biologically active nucleoside analogs. PMID:27200341

  14. Four-gate transistor analog multiplier circuit

    NASA Technical Reports Server (NTRS)

    Mojarradi, Mohammad M. (Inventor); Blalock, Benjamin (Inventor); Cristoloveanu, Sorin (Inventor); Chen, Suheng (Inventor); Akarvardar, Kerem (Inventor)

    2011-01-01

    A differential output analog multiplier circuit utilizing four G.sup.4-FETs, each source connected to a current source. The four G.sup.4-FETs may be grouped into two pairs of two G.sup.4-FETs each, where one pair has its drains connected to a load, and the other par has its drains connected to another load. The differential output voltage is taken at the two loads. In one embodiment, for each G.sup.4-FET, the first and second junction gates are each connected together, where a first input voltage is applied to the front gates of each pair, and a second input voltage is applied to the first junction gates of each pair. Other embodiments are described and claimed.

  15. Analog VLSI neural network integrated circuits

    NASA Astrophysics Data System (ADS)

    Kub, F. J.; Moon, K. K.; Just, E. A.

    1991-12-01

    Two analog very large scale integration (VLSI) vector matrix multiplier integrated circuit chips were designed, fabricated, and partially tested. They can perform both vector-matrix and matrix-matrix multiplication operations at high speeds. The 32 by 32 vector-matrix multiplier chip and the 128 by 64 vector-matrix multiplier chip were designed to perform 300 million and 3 billion multiplications per second, respectively. An additional circuit that has been developed is a continuous-time adaptive learning circuit. The performance achieved thus far for this circuit is an adaptivity of 28 dB at 300 KHz and 11 dB at 15 MHz. This circuit has demonstrated greater than two orders of magnitude higher frequency of operation than any previous adaptive learning circuit.

  16. Automatic digital-analog impedance plethysmograph

    NASA Astrophysics Data System (ADS)

    Goy, C. B.; Mauro, K. A.; Yanicelli, L. M.; Parodi, N. F.; Gómez López, M. A.; Herrera, M. C.

    2016-04-01

    Venous occlusion plethysmography (VOP) is a traditional method widely used to assess limb blood circulation. One common mode to record VOP is by means of evaluating limb volume changes using impedance plethysmography (IP). In this paper the design and implementation of an automatic digital-analog impedance plethysmograph (ADAIP) for VOP is presented. The system is tested using precision resistances in order to calculate its repeatability. Then its global performance is assessed by means of VOP recordings on the upper and me lower limb of a healthy volunteer. The obtained repeatability was very high (95%), and the VOP recordings where the expected ones. It can be concluded that the whole system performs well and that it is suitable for automatic VOP recording.

  17. Disease Resistance Gene Analogs (RGAs) in Plants

    PubMed Central

    Sekhwal, Manoj Kumar; Li, Pingchuan; Lam, Irene; Wang, Xiue; Cloutier, Sylvie; You, Frank M.

    2015-01-01

    Plants have developed effective mechanisms to recognize and respond to infections caused by pathogens. Plant resistance gene analogs (RGAs), as resistance (R) gene candidates, have conserved domains and motifs that play specific roles in pathogens’ resistance. Well-known RGAs are nucleotide binding site leucine rich repeats, receptor like kinases, and receptor like proteins. Others include pentatricopeptide repeats and apoplastic peroxidases. RGAs can be detected using bioinformatics tools based on their conserved structural features. Thousands of RGAs have been identified from sequenced plant genomes. High-density genome-wide RGA genetic maps are useful for designing diagnostic markers and identifying quantitative trait loci (QTL) or markers associated with plant disease resistance. This review focuses on recent advances in structures and mechanisms of RGAs, and their identification from sequenced genomes using bioinformatics tools. Applications in enhancing fine mapping and cloning of plant disease resistance genes are also discussed. PMID:26287177

  18. Analogy between fluid cavitation and fracture mechanics

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Mullen, R. L.; Braun, M. J.

    1983-01-01

    When the stresses imposed on a fluid are sufficiently large, rupture or cavitation can occur. Such conditions can exist in many two-phase flow applications, such as the choked flows, which can occur in seals and bearings. Nonspherical bubbles with large aspect ratios have been observed in fluids under rapid acceleration and high shear fields. These bubbles are geometrically similar to fracture surface patterns (Griffith crack model) existing in solids. Analogies between crack growth in solid and fluid cavitation are proposed and supported by analysis and observation (photographs). Healing phenomena (void condensation), well accepted in fluid mechanics, have been observed in some polymers and hypothesized in solid mechanics. By drawing on the strengths of the theories of solid mechanics and cavitation, a more complete unified theory can be developed.

  19. Holographic brain: a good analogy gone bad

    NASA Astrophysics Data System (ADS)

    Caulfield, H. John

    2002-07-01

    One way of honoring the world's two greatest holographers is to remove from their field the association with the offbeat world of the holographic mind. Basing itself on analogical musings of two very creative scientists who were themselves not holographers, this 'field' of the holographic brain has strayed far from science and into the absurd. So much absurdity has been written by so many people that the one legitimate study of holographic principle in dolphins has been grouped too often with the nonsense. Here is taken most of the 'target statements' form one book. We could not bear to read them all this closely. We will attempt to determine what tidbit of fact led to the statements and to suggest alternative explanations when there is something to explain.

  20. Analog simulation of stochastic satellite response

    NASA Technical Reports Server (NTRS)

    Huang, T. C.; Das, A.

    1984-01-01

    A numerical study was performed on the effects of stochastic geometry and random environmental torques on the pointing accuracy of spinning and three-axis stabilized satellites. The Euler equations for the motions of satellites yielded the stochastic principal moments and a Fokker-Planck analog simulation was employed to model the response vector of a rigid satellite. White noise inputs were obtained from a random number generator. Attention was given to both fast and slow spin satellites. Responses grew with time in all cases. The growth was initially exponential and eventually reached stable values. In comparison with other theoretical techniques, the Fokker-Planck model detailed the most responses and showed that spin-stabilization is preferable for satellites with low inertial noise levels.

  1. Disease Resistance Gene Analogs (RGAs) in Plants.

    PubMed

    Sekhwal, Manoj Kumar; Li, Pingchuan; Lam, Irene; Wang, Xiue; Cloutier, Sylvie; You, Frank M

    2015-01-01

    Plants have developed effective mechanisms to recognize and respond to infections caused by pathogens. Plant resistance gene analogs (RGAs), as resistance (R) gene candidates, have conserved domains and motifs that play specific roles in pathogens' resistance. Well-known RGAs are nucleotide binding site leucine rich repeats, receptor like kinases, and receptor like proteins. Others include pentatricopeptide repeats and apoplastic peroxidases. RGAs can be detected using bioinformatics tools based on their conserved structural features. Thousands of RGAs have been identified from sequenced plant genomes. High-density genome-wide RGA genetic maps are useful for designing diagnostic markers and identifying quantitative trait loci (QTL) or markers associated with plant disease resistance. This review focuses on recent advances in structures and mechanisms of RGAs, and their identification from sequenced genomes using bioinformatics tools. Applications in enhancing fine mapping and cloning of plant disease resistance genes are also discussed.

  2. Analog VLSI neural network integrated circuits

    NASA Technical Reports Server (NTRS)

    Kub, F. J.; Moon, K. K.; Just, E. A.

    1991-01-01

    Two analog very large scale integration (VLSI) vector matrix multiplier integrated circuit chips were designed, fabricated, and partially tested. They can perform both vector-matrix and matrix-matrix multiplication operations at high speeds. The 32 by 32 vector-matrix multiplier chip and the 128 by 64 vector-matrix multiplier chip were designed to perform 300 million and 3 billion multiplications per second, respectively. An additional circuit that has been developed is a continuous-time adaptive learning circuit. The performance achieved thus far for this circuit is an adaptivity of 28 dB at 300 KHz and 11 dB at 15 MHz. This circuit has demonstrated greater than two orders of magnitude higher frequency of operation than any previous adaptive learning circuit.

  3. Analog VLSI system for active drag reduction

    SciTech Connect

    Gupta, B.; Goodman, R.; Jiang, F.; Tai, Y.C.; Tung, S.; Ho, C.M.

    1996-10-01

    In today`s cost-conscious air transportation industry, fuel costs are a substantial economic concern. Drag reduction is an important way to reduce costs. Even a 5% reduction in drag translates into estimated savings of millions of dollars in fuel costs. Drawing inspiration from the structure of shark skin, the authors are building a system to reduce drag along a surface. Our analog VLSI system interfaces with microfabricated, constant-temperature shear stress sensors. It detects regions of high shear stress and outputs a control signal to activate a microactuator. We are in the process of verifying the actual drag reduction by controlling microactuators in wind tunnel experiments. We are encouraged that an approach similar to one that biology employs provides a very useful contribution to the problem of drag reduction. 9 refs., 21 figs.

  4. Synthetic analogs of bacterial quorum sensors

    DOEpatents

    Iyer, Rashi; Ganguly, Kumkum; Silks, Louis A.

    2011-12-06

    Bacterial quorum-sensing molecule analogs having the following structures: ##STR00001## and methods of reducing bacterial pathogenicity, comprising providing a biological system comprising pathogenic bacteria which produce natural quorum-sensing molecule; providing a synthetic bacterial quorum-sensing molecule having the above structures and introducing the synthetic quorum-sensing molecule into the biological system comprising pathogenic bacteria. Further is provided a method of targeted delivery of an antibiotic, comprising providing a synthetic quorum-sensing molecule; chemically linking the synthetic quorum-sensing molecule to an antibiotic to produce a quorum-sensing molecule-antibiotic conjugate; and introducing the conjugate into a biological system comprising pathogenic bacteria susceptible to the antibiotic.

  5. Synthetic analogs of bacterial quorum sensors

    SciTech Connect

    Iyer, Rashi S.; Ganguly, Kumkum; Silks, Louis A.

    2013-01-08

    Bacterial quorum-sensing molecule analogs having the following structures: ##STR00001## and methods of reducing bacterial pathogenicity, comprising providing a biological system comprising pathogenic bacteria which produce natural quorum-sensing molecule; providing a synthetic bacterial quorum-sensing molecule having the above structures and introducing the synthetic quorum-sensing molecule into the biological system comprising pathogenic bacteria. Further is provided a method of targeted delivery of an antibiotic, comprising providing a synthetic quorum-sensing molecule; chemically linking the synthetic quorum-sensing molecule to an antibiotic to produce a quorum-sensing molecule-antibiotic conjugate; and introducing the conjugate into a biological system comprising pathogenic bacteria susceptible to the antibiotic.

  6. Synthesis and biodistribution of radioiodinated nicotine analogs

    SciTech Connect

    Chan, S.M.; Basmadjian, G.P.; Marten, D.F.; Sadek, S.; Magarian, R.A.; Grunder, J.R.; Ice, R.D.

    1984-01-01

    The authors reported previously on the synthesis and biodistribution of radioiodinated 5-iodonicotine. In their continuous effort to search for a potential brain as well as adrenal medulla imaging agent, the authors synthesized four radioiodinated nicotine analogs. The labeled compounds were prepared by brominating nicotinic acid, and reacting the acylated product with the appropriate amines to give the respective amides which were then reduced with diborane to the amines. I-125 labeling was done by halogen exchange. Biodistribution studies performed in female Sprague-Dawley rats showed that all these compounds were taken up rapidly by the brain and the adrenal. The highest uptake of all these compounds in both organs occurred at 2 minutes after tail vein injections. The organ:blood ratios at 2 minutes and the T/sub 1/3/ (min.) of radioactivity in these organs were compared.

  7. Atwood and Poggendorff: an insightful analogy

    NASA Astrophysics Data System (ADS)

    Coelho, R. L.; Borges, P. F.; Karam, R.

    2016-11-01

    Atwood’s treatise, in which the Atwood machine appears, was published in 1784. About 70 years later, Poggendorff showed experimentally that the weight of an Atwood machine is reduced when it is brought to motion. In the present paper, a twofold connection between this experiment and the Atwood machine is established. Firstly, if the Poggendorff apparatus is taken as an ideal one, the equations of motion of the apparatus coincide with the equations of motion of the compound Atwood machine. Secondly, if the Poggendorff apparatus, which works as a lever, is rebalanced, the equations of this equilibrium provide us with the solution for a compound Atwood machine with the same bodies. This analogy is pedagogically useful because it illustrates a common strategy to transform a dynamic in a static situation improving students’ comprehension of Newton’s laws and equilibrium.

  8. Classical analogs of double electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Bai, Zhengyang; Hang, Chao; Huang, Guoxiang

    2013-03-01

    Double electromagnetically induced transparency (DEIT) in a four-level atomic system with tripod-type energy-level configuration is modeled by using two classical systems. The first is a set of three coupled harmonic oscillators subject to frictional forces and external drives and the second is a set of three coupled RLC circuits with electric resistors and alternating voltage sources. It is shown that both of the two classical systems have absorption spectra of DEIT similar to that of the four-level tripod-type atomic system. These classical analogies provide simple and intuitive physical description of quantum interference processes and can be used to illustrate experimental observations of the DEIT in quantum systems.

  9. ANIMAL ANALOGIES IN FIRST IMPRESSIONS OF FACES.

    PubMed

    Zebrowitz, Leslie A; Wadlinger, Heather A; Luevano, Victor X; White, Benjamin M; Xing, Cai; Zhang, Yi

    2011-08-01

    Analogies between humans and animals based on facial resemblance have a long history. We report evidence for reverse anthropomorphism and the extension of facial stereotypes to lions, foxes, and dogs. In the stereotype extension, more positive traits were attributed to animals judged more attractive than con-specifics; more childlike traits were attributed to those judged more babyfaced. In the reverse anthropomorphism, human faces with more resemblance to lions, ascertained by connectionist modeling of facial metrics, were judged more dominant, cold, and shrewd, controlling attractiveness, babyfaceness, and sex. Faces with more resemblance to Labradors were judged warmer and less shrewd. Resemblance to foxes did not predict impressions. Results for lions and dogs were consistent with trait impressions of these animals and support the species overgeneralization hypothesis that evolutionarily adaptive reactions to particular animals are overgeneralized, with people perceived to have traits associated with animals their faces resemble. Other possible explanations are discussed.

  10. ANIMAL ANALOGIES IN FIRST IMPRESSIONS OF FACES

    PubMed Central

    Zebrowitz, Leslie A.; Wadlinger, Heather A.; Luevano, Victor X.; White, Benjamin M.; Xing, Cai; Zhang, Yi

    2013-01-01

    Analogies between humans and animals based on facial resemblance have a long history. We report evidence for reverse anthropomorphism and the extension of facial stereotypes to lions, foxes, and dogs. In the stereotype extension, more positive traits were attributed to animals judged more attractive than con-specifics; more childlike traits were attributed to those judged more babyfaced. In the reverse anthropomorphism, human faces with more resemblance to lions, ascertained by connectionist modeling of facial metrics, were judged more dominant, cold, and shrewd, controlling attractiveness, babyfaceness, and sex. Faces with more resemblance to Labradors were judged warmer and less shrewd. Resemblance to foxes did not predict impressions. Results for lions and dogs were consistent with trait impressions of these animals and support the species overgeneralization hypothesis that evolutionarily adaptive reactions to particular animals are overgeneralized, with people perceived to have traits associated with animals their faces resemble. Other possible explanations are discussed. PMID:25339791

  11. X-Rays from Green Pea Analogs

    NASA Astrophysics Data System (ADS)

    Brorby, Matthew

    2014-09-01

    X-rays may have contributed to the heating and reionization of the IGM in the early universe. High mass X-ray binaries (HMXB) within small, low-metallicity galaxies are expected to be the main source of X-rays at this time. Since studying these high-redshift galaxies is currently impossible, we turn to local analogs that have the same properties the galaxies in the early are expected to have. A number of recent studies have shown an enhanced number of HMXBs in nearby low metallicity galaxies. We propose to observe a sample of metal-deficient luminous compact galaxies (LCG) in order to determine if the X-ray luminosity is enhanced relative to SFR, thereby providing further evidence to the importance of X-rays in the early universe.

  12. Analog circuit for controlling acoustic transducer arrays

    DOEpatents

    Drumheller, Douglas S.

    1991-01-01

    A simplified ananlog circuit is presented for controlling electromechanical transducer pairs in an acoustic telemetry system. The analog circuit of this invention comprises a single electrical resistor which replaces all of the digital components in a known digital circuit. In accordance with this invention, a first transducer in a transducer pair of array is driven in series with the resistor. The voltage drop across this resistor is then amplified and used to drive the second transducer. The voltage drop across the resistor is proportional and in phase with the current to the transducer. This current is approximately 90 degrees out of phase with the driving voltage to the transducer. This phase shift replaces the digital delay required by the digital control circuit of the prior art.

  13. Retrospective Analog Year Analyses Using NASA Satellite Data to Improve USDA's World Agricultural Supply and Demand Estimates

    NASA Technical Reports Server (NTRS)

    Teng, William; Shannon, Harlan

    2011-01-01

    The USDA World Agricultural Outlook Board (WAOB) is responsible for monitoring weather and climate impacts on domestic and foreign crop development. One of WAOB's primary goals is to determine the net cumulative effect of weather and climate anomalies on final crop yields. To this end, a broad array of information is consulted, including maps, charts, and time series of recent weather, climate, and crop observations; numerical output from weather and crop models; and reports from the press, USDA attach s, and foreign governments. The resulting agricultural weather assessments are published in the Weekly Weather and Crop Bulletin, to keep farmers, policy makers, and commercial agricultural interests informed of weather and climate impacts on agriculture. Because both the amount and timing of precipitation significantly affect crop yields, WAOB often uses precipitation time series to identify growing seasons with similar weather patterns and help estimate crop yields for the current growing season, based on observed yields in analog years. Historically, these analog years are visually identified; however, the qualitative nature of this method sometimes precludes the definitive identification of the best analog year. Thus, one goal of this study is to derive a more rigorous, statistical approach for identifying analog years, based on a modified coefficient of determination, termed the analog index (AI). A second goal is to compare the performance of AI for time series derived from surface-based observations vs. satellite-based measurements (NASA TRMM and other data).

  14. The optical analogy for vector fields

    SciTech Connect

    Parker, E.N. . Department of Physics University of Chicago, Chicago, IL . Department of Astronomy)

    1991-09-01

    This paper develops the {ital optical} {ital analogy} for a general vector field {bold F}({bold r}), noting that the projection {bold F}{sub {ital s}} of {bold F} onto any surface locus {ital S} of {del}{times}{bold F} can be expressed as the gradient of a scalar, {bold F}{sub {ital s}}={minus}{del}{phi}. It follows that the field lines of {bold F}{sub {ital s}} pass across {ital S} as if refracted by an index of refraction {vert bar}{bold F}{sub {ital s}}{vert bar}. A sufficiently localized maximum in {vert bar}{bold F}{sub {ital s}}{vert bar} refracts the field so as to produce a gap in the field pattern in {ital S}, with the field bifurcating and passing around the sides, rather than across, the maximum. Such a disruption of the field pattern produces a discontinuity in {bold F}. The optical analogy allows the examination of certain aspects of a vector field that are not otherwise readily accessible. In particular, in the cases of a stationary Eulerian flow {bold v} of an ideal fluid and a magnetostatic field {bold B}, the vectors {bold v} and {bold B} have surface loci in common with their curls. The intrinsic discontinuities around local maxima in {vert bar}{bold v}{vert bar} and {vert bar}{bold B}{vert bar} take the form of vortex sheets and current sheets, respectively, the former playing a fundamental role in the development of hydrodynamic turbulence and the latter playing a major role in heating the x-ray coronas of stars and galaxies.

  15. Discovery and Rational Design of Natural-Product-Derived 2-Phenyl-3,4-dihydro-2H-benzo[f]chromen-3-amine Analogs as Novel and Potent Dipeptidyl Peptidase 4 (DPP-4) Inhibitors for the Treatment of Type 2 Diabetes.

    PubMed

    Li, Shiliang; Xu, Hongling; Cui, Shichao; Wu, Fangshu; Zhang, Youli; Su, Mingbo; Gong, Yinghui; Qiu, Shaobing; Jiao, Qian; Qin, Chun; Shan, Jiwei; Zhang, Ming; Wang, Jiawei; Yin, Qiao; Xu, Minghao; Liu, Xiaofeng; Wang, Rui; Zhu, Lili; Li, Jia; Xu, Yufang; Jiang, Hualiang; Zhao, Zhenjiang; Li, Jingya; Li, Honglin

    2016-07-28

    Starting from the lead isodaphnetin, a natural product inhibitor of DPP-4 discovered through a target fishing docking based approach, a series of novel 2-phenyl-3,4-dihydro-2H-benzo[f]chromen-3-amine derivatives as potent DPP-4 inhibitors are rationally designed utilizing highly efficient 3D molecular similarity based scaffold hopping as well as electrostatic complementary methods. Those ingenious drug design strategies bring us approximate 7400-fold boost in potency. Compounds 22a and 24a are the most potent ones (IC50 ≈ 2.0 nM) with good pharmacokinetic profiles. Compound 22a demonstrated stable pharmacological effect. A 3 mg/kg oral dose provided >80% inhibition of DPP-4 activity within 24 h, which is comparable to the performance of the long-acting control omarigliptin. Moreover, the efficacy of 22a in improving the glucose tolerance is also comparable with omarigliptin. In this study, not only promising DPP-4 inhibitors as long acting antidiabetic that are clinically on demand are identified, but the target fish docking and medicinal chemistry strategies were successfully implemented.

  16. Somatostatin Analog Therapy in Small Cell Lung Cancer.

    PubMed

    Tartarone, Alfredo; Lerose, Rosa; Aieta, Michele

    2016-05-01

    Chemotherapy represents the cornerstone of treatment for patients with small cell lung cancer (SCLC); however, standard therapy has reached a plateau in improving patient survival with overall disappointing results. The demonstration that SCLC expresses neuroendocrine markers, such as somatostatin (SST) receptors, has led to use SST analogs or radiolabeled SST analogs in the treatment of SCLC patients. In the current review, we would focus on the possible role of SST analogs in SCLC. PMID:27067504

  17. Analogy use in naturalistic settings: the influence of audience, emotion, and goals.

    PubMed

    Blanchette, I; Dunbar, K

    2001-07-01

    The ways in which analogy was used in a nonexperimental environment-politics-was investigated. We used the framework developed in analogy research to analyze the selection of analogical sources in political discourse. We took all the analogies reported in newspapers during the final week of a referendum campaign in Canada and analyzed the features of the different analogies used. We identified 234 analogies and analyzed the range over which analogies were used, semantic categories of analogies, goals of the analogizer, and emotional connotation of the analogies. Our results reveal that analogy was frequently used, that over two-thirds of the analogical sources were nonpolitical, and that many of the sources had strong emotional connotations. Furthermore, the goal of the analogizer influenced the selection of sources. We conclude that characteristics of the audience and emotionality of the source analog are important features in the selection of source analogs.

  18. ISS Update: ISTAR -- International Space Station Testbed for Analog Research

    NASA Video Gallery

    NASA Public Affairs Officer Kelly Humphries interviews Sandra Fletcher, EVA Systems Flight Controller. They discuss the International Space Station Testbed for Analog Research (ISTAR) activity that...

  19. Analog solar system model relates celestial bodies spatially

    NASA Technical Reports Server (NTRS)

    Baerg, H. R.

    1966-01-01

    Portable analog planetarium indicates the relative time and space angular locations of the sun and planets. Distance measuring scales, angular direction indicators, and typical probe trajectories are included.

  20. CRC handbook of neurohypophyseal hormone analogs. Volume 2

    SciTech Connect

    Jost, K.; Lebl, M.; Brtnik, F.

    1987-01-01

    This book is discussed in two parts. The Part 1 discusses the: Prohormones and Hormonogens of Neuro-hypophyseal Hormones, Analogs with Inhibitory properties. Analogs with Dissociated and/or High activities. Introduction. Uterotonic Activity. Galactogogic Activity. Pressor Activity. Antidiuretic Activity. References. Part 2 discusses the Other Important Activities. CNS Activities. Corticotropin- and ..beta..-Entriuretic Action. Natriferic Action. References. Practical Use in Human and Veterinary Medicine. Introduction. Methyloxytocin. Deamino-Oxytocin. Cargutocin. Glypressin. Octapressin. Desmopressin. Analogs Clinically Tried But Not Introduced into Production and Routine Clinical Practice. References. Tables of Analogs and Index.

  1. ROTATION PERIODS AND AGES OF SOLAR ANALOGS AND SOLAR TWINS REVEALED BY THE KEPLER MISSION

    SciTech Connect

    Do Nascimento Jr, J.-D.; Meibom, S.; García, R. A.; Salabert, D.; Ceillier, T.; Anthony, F.; Da Costa, J. S.; Castro, M.; Barnes, S. A.

    2014-08-01

    A new sample of solar analogs and twin candidates has been constructed and studied, paying particular attention to their light curves from NASA's Kepler mission. This Letter aims to assess their evolutionary status, derive their rotation and ages, and identify those which are solar analogs or solar twin candidates. We separate out the subgiants that compose a large fraction of the asteroseismic sample, and which show an increase in the average rotation period as the stars ascend the subgiant branch. The rotation periods of the dwarfs, ranging from 6 to 30 days and averaging 19 days, allow us to assess their individual evolutionary states on the main sequence and to derive their ages using gyrochronology. These ages are found to be in agreement with a correlation coefficient of r = 0.79 with independent asteroseismic ages, where available. As a result of this investigation, we are able to identify 34 stars as solar analogs and 22 of them as solar twin candidates.

  2. Mutational biosynthesis of neomycin analogs by a mutant of neomycin-producing Streptomyces fradiae.

    PubMed

    Shi, Guanying; Zhang, Xingang; Wu, Lang; Xie, Jin; Tao, Ke; Hou, Taiping

    2011-11-01

    Neomycin, produced by Streptomyces fradiae, has been widely used for the treatment of bacterial infections in clinical and agricultural applications. In this study, a neomycin nonproducing mutant of S. fradiae was obtained by gene disruption technique for mutational biosynthesis. A crucial gene neoC (neo7) which encodes 2-deoxystreptamine (2-DOS) synthases was disrupted. The mutant could resume producing neomycin in the presence of 2-DOS. Salen derivatives of 2-DOS were synthesized and individually added to cultures of the mutant. Antibacterial activity of the mutasynthesis products against Staphylococcus aureus and four plant pathogenic bacteria (Pseudomonas solanacarum, Erwinia carotovora, Xanthomonas oryzae, and Xanthomonas campestris) was detected quantitatively by Oxford cup method. It is suggested that all 2-DOS derivatives were incorporated by the mutant into new active neomycin analogs except for 2-DOS derivative 2d ((1R,2r,3S,4R,6S)-4,6-bis((E)-3,5-di-tert-butyl-2-hydroxybenzylideneamino)cyclohexane-1,2,3-triol). Neomycin analogs produced by feeding 2-DOS derivative 2a ((1R,2r,3S,4R,6S)-4,6-bis((E)-2 hydroxybenzylideneamino)cyclohexane-1,2,3-triol) to cultures of the mutant displayed a similar antibacterial activity with neomycin produced by wild strain.

  3. Validation of acoustic-analogy predictions for sound radiated by turbulence

    NASA Astrophysics Data System (ADS)

    Whitmire, Julia; Sarkar, Sutanu

    2000-02-01

    Predicting sound radiated by turbulence is of interest in aeroacoustics, hydroacoustics, and combustion noise. Significant improvements in computer technology have renewed interest in applying numerical techniques to predict sound from turbulent flows. One such technique is a hybrid approach in which the turbulence is computed using a method such as direct numerical simulation (DNS) or large eddy simulation (LES), and the sound is calculated using an acoustic analogy. In this study, sound from a turbulent flow is computed using DNS, and the DNS results are compared with acoustic-analogy predictions for mutual validation. The source considered is a three-dimensional region of forced turbulence which has limited extent in one coordinate direction and is periodic in the other two directions. Sound propagates statistically as a plane wave from the turbulence to the far field. The cases considered here have a small turbulent Mach number so that the source is spatially compact; that is, the turbulence integral scale is much smaller than the acoustic wavelength. The scaling of the amplitude and frequency of the far-field sound for the problem considered are derived in an analysis based on Lighthill's acoustic analogy. The analytical results predict that the far-field sound should exhibit "dipole-type" behavior; the root-mean-square pressure in the acoustic far field should increase as the cube of the turbulent Mach number. The acoustic power normalized by the turbulent dissipation rate is also predicted to scale as turbulent Mach number cubed. Agreement between the DNS results and the acoustic-analogy predictions is good. This study verifies the ability of the Lighthill acoustic analogy to predict sound generated by a three-dimensional, turbulent source containing many length and time scales.

  4. Partitioning, diffusion, and ligand binding of raft lipid analogs in model and cellular plasma membranes.

    PubMed

    Sezgin, Erdinc; Levental, Ilya; Grzybek, Michal; Schwarzmann, Günter; Mueller, Veronika; Honigmann, Alf; Belov, Vladimir N; Eggeling, Christian; Coskun, Unal; Simons, Kai; Schwille, Petra

    2012-07-01

    Several simplified membrane models featuring coexisting liquid disordered (Ld) and ordered (Lo) lipid phases have been developed to mimic the heterogeneous organization of cellular membranes, and thus, aid our understanding of the nature and functional role of ordered lipid-protein nanodomains, termed "rafts". In spite of their greatly reduced complexity, quantitative characterization of local lipid environments using model membranes is not trivial, and the parallels that can be drawn to cellular membranes are not always evident. Similarly, various fluorescently labeled lipid analogs have been used to study membrane organization and function in vitro, although the biological activity of these probes in relation to their native counterparts often remains uncharacterized. This is particularly true for raft-preferring lipids ("raft lipids", e.g. sphingolipids and sterols), whose domain preference is a strict function of their molecular architecture, and is thus susceptible to disruption by fluorescence labeling. Here, we analyze the phase partitioning of a multitude of fluorescent raft lipid analogs in synthetic Giant Unilamellar Vesicles (GUVs) and cell-derived Giant Plasma Membrane Vesicles (GPMVs). We observe complex partitioning behavior dependent on label size, polarity, charge and position, lipid headgroup, and membrane composition. Several of the raft lipid analogs partitioned into the ordered phase in GPMVs, in contrast to fully synthetic GUVs, in which most raft lipid analogs mis-partitioned to the disordered phase. This behavior correlates with the greatly enhanced order difference between coexisting phases in the synthetic system. In addition, not only partitioning, but also ligand binding of the lipids is perturbed upon labeling: while cholera toxin B binds unlabeled GM1 in the Lo phase, it binds fluorescently labeled GMI exclusively in the Ld phase. Fluorescence correlation spectroscopy (FCS) by stimulated emission depletion (STED) nanoscopy on intact

  5. Evaluating The Global Inventory of Planetary Analog Environments on Earth: An Ontological Approach

    NASA Astrophysics Data System (ADS)

    Conrad, P. G.

    2010-12-01

    Introduction: Field sites on Earth are routinely used to simulate planetary environments so that we can try to understand the evidence of processes such as sedimentary deposition, weathering, evolution of habitable environments, and behavior of spacecraft and instrumentation prior to selection of mission architectures, payload investigations and landing sites for in situ exploration of other planets. The rapid evolution of astrobiology science drivers for space exploration as well as increasing capability to explore planetary surfaces in situ has led to a proliferation of declarations that various Earth environments are analogs for less accessible planetary environments. We have not yet progressed to standardized measures of analog fidelity, and the analog value of field sites can be variable de-pending upon a variety of factors. Here we present a method of evaluating the fidelity and hence utility of analog environments by using an ontological approach to evaluating how well the analogs work. The use of ontologies as specification constructs is now quite common in artificial intelligence, systems engineering, business development and various informatics systems. We borrow from these developments just as they derive from the original use of ontology in philosophy, where it was meant as a systematic approach to describing the fundamental elements that define “being,” or existence [1]. An ontology is a framework for the specification of a concept or domain of interest. The knowledge regarding that domain, eg., inventory of objects, hierarchical classes, relationships and functions is what describes and defines the domain as a declarative formalism [2]. In the case of planetary environments, one can define a list of fundamen-tal attributes without which the domain (environment) in question must be defined (classified) otherwise. In particu-lar this is problematic when looking at ancient environments because of their alteration over time. In other words, their

  6. Cholesterol Analogs with Degradation-resistant Alkyl Side Chains Are Effective Mycobacterium tuberculosis Growth Inhibitors.

    PubMed

    Frank, Daniel J; Zhao, Yan; Wong, Siew Hoon; Basudhar, Debashree; De Voss, James J; Ortiz de Montellano, Paul R

    2016-04-01

    Cholest-4-en-3-one, whether added exogenously or generated intracellularly from cholesterol, inhibits the growth ofMycobacterium tuberculosiswhen CYP125A1 and CYP142A1, the cytochrome P450 enzymes that initiate degradation of the sterol side chain, are disabled. Here we demonstrate that a 16-hydroxy derivative of cholesterol, which was previously reported to inhibit growth ofM. tuberculosis, acts by preventing the oxidation of the sterol side chain even in the presence of the relevant cytochrome P450 enzymes. The finding that (25R)-cholest-5-en-3β,16β,26-triol (1) (and its 3-keto metabolite) inhibit growth suggests that cholesterol analogs with non-degradable side chains represent a novel class of anti-mycobacterial agents. In accord with this, two cholesterol analogs with truncated, fluorinated side chains have been synthesized and shown to similarly block the growth in culture ofM. tuberculosis.

  7. Glucagon-Like Peptide 1 Analogs and their Effects on Pancreatic Islets.

    PubMed

    Tudurí, Eva; López, Miguel; Diéguez, Carlos; Nadal, Angel; Nogueiras, Rubén

    2016-05-01

    Glucagon-like peptide 1 (GLP-1) exerts many actions that improve glycemic control. GLP-1 stimulates glucose-stimulated insulin secretion and protects β cells, while its extrapancreatic effects include cardioprotection, reduction of hepatic glucose production, and regulation of satiety. Although an appealing antidiabetic drug candidate, the rapid degradation of GLP-1 by dipeptidyl peptidase 4 (DPP-4) means that its therapeutic use is unfeasible, and this prompted the development of two main GLP-1 therapies: long-acting GLP-1 analogs and DPP-4 inhibitors. In this review, we focus on the pancreatic effects exerted by current GLP-1 derivatives used to treat diabetes. Based on the results from in vitro and in vivo studies in humans and animal models, we describe the specific actions of GLP-1 analogs on the synthesis, processing, and secretion of insulin, islet morphology, and β cell proliferation and apoptosis. PMID:27062006

  8. Unusual C7- versus Normal 5'-O-Dimethoxytritylation of 6-Arylpyrrolocytidine Analogs.

    PubMed

    Suchý, Mojmír; Ettles, Christie; Wisner, James A; Matarazzo, Augusto; Hudson, Robert H E

    2016-09-16

    Fluorescent deoxynucleosides possessing the modified bases 6-(2-benzo[b]furyl)- and 6-(2-furyl)pyrrolocytosine (BFpC and FpC) have been synthesized along with the quencher nucleosides possessing 6-{4-[(4-dimethylamino)azo]phenyl}pyrrolocytosine (DABCYLpC) and 6-(p-nitrophenyl)pyrrolocytosine (p-NO2-PhpC) nucleobase analogs. Standard treatment of BFpC, FpC, DABCYLpC, and p-NO2-PhpC with dimethoxytrityl chloride (DMT-Cl) led to the unusual substitution on the C7 of the pyrrolocytosine skeleton. The desired 5'-O-DMT-protected nucleoside analogs were synthesized from suitably protected 5'-O-DMT cytidines. Subsequent phosphitylation smoothly afforded BFpC-, FpC-, DABCYLpC-, and p-NO2-PhpC-derived monomers suitable for standard oligonucleotide synthesis. PMID:27529362

  9. Anti-inflammatory and antioxidant properties of a novel resveratrol-salicylate hybrid analog.

    PubMed

    Aldawsari, Fahad S; Aguiar, Rafael Pazinatto; Wiirzler, Luiz Alexandre Marques; Aguayo-Ortiz, Rodrigo; Aljuhani, Naif; Cuman, Roberto Kenji Nakamura; Medina-Franco, José L; Siraki, Arno G; Velázquez-Martínez, Carlos A

    2016-03-01

    Resveratrol is a natural compound with a plethora of activities as well as limitations. We recently reported a series of resveratrol-salicylate analogs with potential chemopreventive activity. Herein, we report the anti-inflammatory and antioxidant properties of these resveratrol derivatives. Using an in vitro COX inhibition assay, and two in vivo protocols (carrageenan-induced peritonitis and paw edema), we identified a novel compound (C10) as a potent anti-inflammatory agent. The enhanced potency of C10 was associated with the ability of C10 to decrease the activity of myeloperoxidase (MPO) enzyme at 10mg/kg, whereas resveratrol and it's natural analog (TMS) did not exert the same effect. Additionally, C10 significantly reduced the concentration of intracellular reactive oxygen species. Because of the proven association between cancer, inflammation, and oxidative stress, we believe that C10 is a promising chemopreventive molecule.

  10. Brassinosteroids and analogs as neuroprotectors: synthesis and structure-activity relationships.

    PubMed

    Ismaili, Jihane; Boisvert, Martin; Longpré, Fanny; Carange, Julie; Le Gall, Céline; Martinoli, Maria-Grazia; Daoust, Benoit

    2012-01-01

    We have demonstrated previously that the brassinosteroid (BR) 24-epibrassinolide exerts neuroprotective effects deriving from its antioxidative properties. In this study, we synthesized 2 natural BRs and 5 synthetic analogs and analyzed their neuroprotective actions in neuronal PC12 cells, against 1-methyl-4-phenylpyridinium (MPP(+)), a neurotoxin known to induce oxidative stress and degenerescence of dopaminergic neurons characteristic of Parkinsonian brains. We also tested the neuroprotective potential of 2 commercially available BRs. Our results disclosed that 6 of the 9 BRs and analogs tested protected neuronal PC12 cells against MPP(+) toxicity. In addition, our structure-activity study suggests that the steroid B-ring and lateral chain play an important role for their neuroprotective action.

  11. Analogy, Cognitive Architecture and Universal Construction: A Tale of Two Systematicities

    PubMed Central

    Phillips, Steven

    2014-01-01

    Cognitive science recognizes two kinds of systematicity: (1) as the property where certain cognitive capacities imply certain other related cognitive capacities (Fodor and Pylyshyn); and (2) as the principle that analogical mappings based on collections of connected relations are preferred over relations in isolation (Gentner). Whether these kinds of systematicity are two aspects of a deeper property of cognition is hitherto unknown. Here, it is shown that both derive from the formal, category-theoretic notion of universal construction. In conceptual/psychological terms, a universal construction is a form of optimization of cognitive resources: optimizing the re-utilization of common component processes for common task components. Systematic cognitive capacity and the capacity for analogy are hallmarks of human cognition, which suggests that universal constructions (in the category-theoretic sense) are a crucial component of human cognitive architecture. PMID:24586555

  12. Synthesis of a suite of click-compatible sugar analogs for probing carbohydrate metabolism.

    PubMed

    Wang, Bo; McClosky, Daniel D; Anderson, Charles T; Chen, Gong

    2016-10-01

    Metabolic labeling based on the click chemistry between alkynyl and azido groups offers a powerful tool to study the function of carbohydrates in living systems, including plants. Herein, we describe the chemical synthesis of six alkynyl-modified sugars designed as analogs to D-glucose, D-mannose, L-rhamnose and sucrose present in plant cell walls. Among these new alkynyl probes, four of them are the 6-deoxy-alkynyl analogs of the corresponding sugars and do not possess any 6-OH groups. The other two are based on a new structural design, in which an ethynyl group is incorporated at the C-6 position of the sugar and the 6-OH group remains. The synthetic routes for both types of probes share common aldehyde intermediates, which are derived from the corresponding 6-OH precursor with other hydroxy groups protected. The overall synthesis sequence of these probes is efficient, concise, and scalable. PMID:27447057

  13. How strategists really think. Tapping the power of analogy.

    PubMed

    Gavetti, Giovanni; Rivkin, Jan W

    2005-04-01

    Leaders tend to be so immersed in the specifics of strategy that they rarely stop to think how much of their reasoning is done by analogy. As a result, they miss useful insights that psychologists and other scientists have generated about analogies' pitfalls. Managers who pay attention to their own analogical thinking will make better strategic decisions and fewer mistakes. Charles Lazarus was inspired by the supermarket when he founded Toys R Us; Intel promoted its low-end chips to avoid becoming like U.S. Steel; and Circuit City created CarMax because it saw the used-car market as analogous to the consumer-electronics market. Each example displays the core elements of analogical reasoning: a novel problem or a new opportunity, a specific prior context that managers deem to be similar in its essentials, and a solution that managers can transfer from its original setting to the new one. Analogical reasoning is a powerful tool for sparking breakthrough ideas. But dangers arise when analogies are built on surface similarities (headlong diversification based on loose analogies played a role in Enron's collapse, for instance). Psychologists have discovered that it's all too easy to overlook the superficiality of analogies. The situation is further complicated by people's tendency to hang on to beliefs even after contrary evidence comes along (a phenomenon known as anchoring) and their tendency to seek only the data that confirm their beliefs (an effect known as the confirmation bias). Four straightforward steps can improve a management team's odds of using an analogy well: Recognize the analogy and identify its purpose; thoroughly understand its source; determine whether the resemblance is more than superficial; and decide whether the original strategy, properly translated, will work in the target industry. PMID:15807039

  14. How strategists really think. Tapping the power of analogy.

    PubMed

    Gavetti, Giovanni; Rivkin, Jan W

    2005-04-01

    Leaders tend to be so immersed in the specifics of strategy that they rarely stop to think how much of their reasoning is done by analogy. As a result, they miss useful insights that psychologists and other scientists have generated about analogies' pitfalls. Managers who pay attention to their own analogical thinking will make better strategic decisions and fewer mistakes. Charles Lazarus was inspired by the supermarket when he founded Toys R Us; Intel promoted its low-end chips to avoid becoming like U.S. Steel; and Circuit City created CarMax because it saw the used-car market as analogous to the consumer-electronics market. Each example displays the core elements of analogical reasoning: a novel problem or a new opportunity, a specific prior context that managers deem to be similar in its essentials, and a solution that managers can transfer from its original setting to the new one. Analogical reasoning is a powerful tool for sparking breakthrough ideas. But dangers arise when analogies are built on surface similarities (headlong diversification based on loose analogies played a role in Enron's collapse, for instance). Psychologists have discovered that it's all too easy to overlook the superficiality of analogies. The situation is further complicated by people's tendency to hang on to beliefs even after contrary evidence comes along (a phenomenon known as anchoring) and their tendency to seek only the data that confirm their beliefs (an effect known as the confirmation bias). Four straightforward steps can improve a management team's odds of using an analogy well: Recognize the analogy and identify its purpose; thoroughly understand its source; determine whether the resemblance is more than superficial; and decide whether the original strategy, properly translated, will work in the target industry.

  15. Derivative chameleons

    NASA Astrophysics Data System (ADS)

    Noller, Johannes

    2012-07-01

    We consider generalized chameleon models where the conformal coupling between matter and gravitational geometries is not only a function of the chameleon field phi, but also of its derivatives via higher order co-ordinate invariants (such as ∂μphi∂μphi,squphi,...). Specifically we consider the first such non-trivial conformal factor A(phi,∂μphi∂μphi). The associated phenomenology is investigated and we show that such theories have a new generic mass-altering mechanism, potentially assisting the generation of a sufficiently large chameleon mass in dense environments. The most general effective potential is derived for such derivative chameleon setups and explicit examples are given. Interestingly this points us to the existence of a purely derivative chameleon protected by a shift symmetry for phi → phi+c. We also discuss potential ghost-like instabilities associated with mass-lifting mechanisms and find another, mass-lowering and instability-free, branch of solutions. This suggests that, barring fine-tuning, stable derivative models are in fact typically anti-chameleons that suppress the field's mass in dense environments. Furthermore we investigate modifications to the thin-shell regime and prove a no-go theorem for chameleon effects in non-conformal geometries of the disformal type.

  16. Derivative chameleons

    SciTech Connect

    Noller, Johannes

    2012-07-01

    We consider generalized chameleon models where the conformal coupling between matter and gravitational geometries is not only a function of the chameleon field φ, but also of its derivatives via higher order co-ordinate invariants (such as ∂{sub μ}φ∂{sup μ}φ,□φ,...). Specifically we consider the first such non-trivial conformal factor A(φ,∂{sub μ}φ∂{sup μ}φ). The associated phenomenology is investigated and we show that such theories have a new generic mass-altering mechanism, potentially assisting the generation of a sufficiently large chameleon mass in dense environments. The most general effective potential is derived for such derivative chameleon setups and explicit examples are given. Interestingly this points us to the existence of a purely derivative chameleon protected by a shift symmetry for φ → φ+c. We also discuss potential ghost-like instabilities associated with mass-lifting mechanisms and find another, mass-lowering and instability-free, branch of solutions. This suggests that, barring fine-tuning, stable derivative models are in fact typically anti-chameleons that suppress the field's mass in dense environments. Furthermore we investigate modifications to the thin-shell regime and prove a no-go theorem for chameleon effects in non-conformal geometries of the disformal type.

  17. Defining applied behavior analysis: An historical analogy

    PubMed Central

    Deitz, Samuel M.

    1982-01-01

    This article examines two criteria for a definition of applied behavior analysis. The criteria are derived from a 19th century attempt to establish medicine as a scientific field. The first criterion, experimental determinism, specifies the methodological boundaries of an experimental science. The second criterion, philosophic doubt, clarifies the tentative nature of facts and theories derived from those facts. Practices which will advance the science of behavior are commented upon within each criteria. To conclude, the problems of a 19th century form of empiricism in medicine are related to current practices in applied behavior analysis. PMID:22478557

  18. Resonant Tunneling Analog-To-Digital Converter

    NASA Technical Reports Server (NTRS)

    Broekaert, T. P. E.; Seabaugh, A. C.; Hellums, J.; Taddiken, A.; Tang, H.; Teng, J.; vanderWagt, J. P. A.

    1995-01-01

    As sampling rates continue to increase, current analog-to-digital converter (ADC) device technologies will soon reach a practical resolution limit. This limit will most profoundly effect satellite and military systems used, for example, for electronic countermeasures, electronic and signal intelligence, and phased array radar. New device and circuit concepts will be essential for continued progress. We describe a novel, folded architecture ADC which could enable a technological discontinuity in ADC performance. The converter technology is based on the integration of multiple resonant tunneling diodes (RTD) and hetero-junction transistors on an indium phosphide substrate. The RTD consists of a layered semiconductor hetero-structure AlAs/InGaAs/AlAs(2/4/2 nm) clad on either side by heavily doped InGaAs contact layers. Compact quantizers based around the RTD offer a reduction in the number of components and a reduction in the input capacitance Because the component count and capacitance scale with the number of bits N, rather than by 2 (exp n) as in the flash ADC, speed can be significantly increased, A 4-bit 2-GSps quantizer circuit is under development to evaluate the performance potential. Circuit designs for ADC conversion with a resolution of 6-bits at 25GSps may be enabled by the resonant tunneling approach.

  19. Photometric properties of Mars soils analogs

    USGS Publications Warehouse

    Pommerol, A.; Thomas, N.; Jost, B.; Beck, P.; Okubo, C.; McEwen, A.S.

    2013-01-01

    We have measured the bidirectional reflectance of analogs of dry, wet, and frozen Martian soils over a wide range of phase angles in the visible spectral range. All samples were produced from two geologic samples: the standard JSC Mars-1 soil simulant and Hawaiian basaltic sand. In a first step, experiments were conducted with the dry samples to investigate the effects of surface texture. Comparisons with results independently obtained by different teams with similar samples showed a satisfying reproducibility of the photometric measurements as well as a noticeable influence of surface textures resulting from different sample preparation procedures. In a second step, water was introduced to produce wet and frozen samples and their photometry investigated. Optical microscope images of the samples provided information about their microtexture. Liquid water, even in relatively low amount, resulted in the disappearance of the backscattering peak and the appearance of a forward-scattering peak whose intensity increases with the amount of water. Specular reflections only appeared when water was present in an amount large enough to allow water to form a film at the surface of the sample. Icy samples showed a wide variability of photometric properties depending on the physical properties of the water ice. We discuss the implications of these measurements in terms of the expected photometric behavior of the Martian surface, from equatorial to circum-polar regions. In particular, we propose some simple photometric criteria to improve the identification of wet and/or icy soils from multiple observations under different geometries.

  20. Natural CO2 Analogs for Carbon Sequestration

    SciTech Connect

    Scott H. Stevens; B. Scott Tye

    2005-07-31

    The report summarizes research conducted at three naturally occurring geologic CO{sub 2} fields in the US. The fields are natural analogs useful for the design of engineered long-term storage of anthropogenic CO{sub 2} in geologic formations. Geologic, engineering, and operational databases were developed for McElmo Dome in Colorado; St. Johns Dome in Arizona and New Mexico; and Jackson Dome in Mississippi. The three study sites stored a total of 2.4 billion t (46 Tcf) of CO{sub 2} equivalent to 1.5 years of power plant emissions in the US and comparable in size with the largest proposed sequestration projects. The three CO{sub 2} fields offer a scientifically useful range of contrasting geologic settings (carbonate vs. sandstone reservoir; supercritical vs. free gas state; normally pressured vs. overpressured), as well as different stages of commercial development (mostly undeveloped to mature). The current study relied mainly on existing data provided by the CO{sub 2} field operator partners, augmented with new geochemical data. Additional study at these unique natural CO{sub 2} accumulations could further help guide the development of safe and cost-effective design and operation methods for engineered CO{sub 2} storage sites.

  1. The MARS2013 Mars analog mission.

    PubMed

    Groemer, Gernot; Soucek, Alexander; Frischauf, Norbert; Stumptner, Willibald; Ragonig, Christoph; Sams, Sebastian; Bartenstein, Thomas; Häuplik-Meusburger, Sandra; Petrova, Polina; Evetts, Simon; Sivenesan, Chan; Bothe, Claudia; Boyd, Andrea; Dinkelaker, Aline; Dissertori, Markus; Fasching, David; Fischer, Monika; Föger, Daniel; Foresta, Luca; Fritsch, Lukas; Fuchs, Harald; Gautsch, Christoph; Gerard, Stephan; Goetzloff, Linda; Gołebiowska, Izabella; Gorur, Paavan; Groemer, Gerhard; Groll, Petra; Haider, Christian; Haider, Olivia; Hauth, Eva; Hauth, Stefan; Hettrich, Sebastian; Jais, Wolfgang; Jones, Natalie; Taj-Eddine, Kamal; Karl, Alexander; Kauerhoff, Tilo; Khan, Muhammad Shadab; Kjeldsen, Andreas; Klauck, Jan; Losiak, Anna; Luger, Markus; Luger, Thomas; Luger, Ulrich; McArthur, Jane; Moser, Linda; Neuner, Julia; Orgel, Csilla; Ori, Gian Gabriele; Paternesi, Roberta; Peschier, Jarno; Pfeil, Isabella; Prock, Silvia; Radinger, Josef; Ramirez, Barbara; Ramo, Wissam; Rampey, Mike; Sams, Arnold; Sams, Elisabeth; Sandu, Oana; Sans, Alejandra; Sansone, Petra; Scheer, Daniela; Schildhammer, Daniel; Scornet, Quentin; Sejkora, Nina; Stadler, Andrea; Stummer, Florian; Taraba, Michael; Tlustos, Reinhard; Toferer, Ernst; Turetschek, Thomas; Winter, Egon; Zanella-Kux, Katja

    2014-05-01

    We report on the MARS2013 mission, a 4-week Mars analog field test in the northern Sahara. Nineteen experiments were conducted by a field crew in Morocco under simulated martian surface exploration conditions, supervised by a Mission Support Center in Innsbruck, Austria. A Remote Science Support team analyzed field data in near real time, providing planning input for the management of a complex system of field assets; two advanced space suit simulators, four robotic vehicles, an emergency shelter, and a stationary sensor platform in a realistic work flow were coordinated by a Flight Control Team. A dedicated flight planning group, external control centers for rover tele-operations, and a biomedical monitoring team supported the field operations. A 10 min satellite communication delay and other limitations pertinent to human planetary surface activities were introduced. The fields of research for the experiments were geology, human factors, astrobiology, robotics, tele-science, exploration, and operations research. This paper provides an overview of the geological context and environmental conditions of the test site and the mission architecture, in particular the communication infrastructure emulating the signal travel time between Earth and Mars. We report on the operational work flows and the experiments conducted, including a deployable shelter prototype for multiple-day extravehicular activities and contingency situations.

  2. Natural Analog Studies at Pena Blanca, Mexico

    SciTech Connect

    A.M. Simmons

    2005-07-11

    The significance of the Pena Blanca uranium deposits in the State of Chihuahua, Mexico as potential natural analogs for a nuclear waste repository in unsaturated welded tuff was first recognized in the 1980s. In the 1970s, the Pena Blanca region was a major target of uranium exploration and exploitation by the Mexican government. Since then the Nopal I uranium deposit has been studied extensively by researchers in the U.S., Mexico, and Europe. The Nopal I deposit represents an environment similar to that of the proposed high-level radioactive waste repository at Yucca Mountain in many ways. Both are located in semi-arid regions. Both are located in Tertiary rhyolitic tuffs overlying carbonate rocks that have been subjected to basin and range-style tectonic deformation. Both are located in a chemically oxidizing, unsaturated zone 200 m or more above the water table. The alteration of uraninite to secondary minerals at Nopal I may be similar to the alteration of uranium fuel rods in this type of setting. Investigations at Nopal I and in the surrounding Sierra Pena Blanca have included detailed outcrop mapping, hydrologic and isotopic studies of flow and transport, studies of mineral alteration, modeling, and performance assessment.

  3. A fungal analog for newfoundland ediacaran fossils?

    PubMed

    Peterson, Kevin J; Waggoner, Ben; Hagadorn, James W

    2003-02-01

    We propose that some of the more conspicuous Ediacaran fossils from the Avalon Peninsula of Newfoundland, including Aspidella, Charnia, and Charniodiscus, were biologically similar to members of the Kingdom Fungi. These organisms were multicellular or multinuclear, lived below the photic zone, could not move or defoul themselves, did not exhibit taphonomic shrinkage, and were not transported or moved. Aspidella, in particular, appears to exhibit indeterminate growth without a maximum size constraint, and appears to show growth zonations similar to modern mycelia. Other fossils from this deposit exhibit a fractal-like growth pattern. Together, these features falsify algal, lichen, and metazoan interpretations of these fossils, yet reflect characteristics of modern fungal mycelia. We emphasize that although no Mistaken Point fossil appears to be a metazoan, not all of the Mistaken Point taxa, and not all of the Ediacaran organisms in general, can reasonably be interpreted using a fungal analogy. Furthermore, the hypothesis that these fossils were functionally fungus-like need not imply that the organisms were members of the crown-group Fungi. We propose further tests for evaluating both this functional hypothesis and the phylogenetic hypothesis that these organisms were members of the total-group Fungi.

  4. Heavy ion irradiation of astrophysical ice analogs

    NASA Astrophysics Data System (ADS)

    Duarte, Eduardo Seperuelo; Domaracka, Alicja; Boduch, Philippe; Rothard, Hermann; Balanzat, Emmanuel; Dartois, Emmanuel; Pilling, Sergio; Farenzena, Lucio; da Silveira, Enio Frota

    Icy grain mantles consist of small molecules containing hydrogen, carbon, oxygen and nitrogen atoms (e.g. H2O, CO, CO2, NH3). Such ices, present in different astrophysical environments (giant planets satellites, comets, dense clouds, and protoplanetary disks), are subjected to irradiation of different energetic particles: UV radiation, ion bombardment (solar and stellar wind as well as galactic cosmic rays), and secondary electrons due to cosmic ray ionization of H2. The interaction of these particles with astrophysical ice analogs has been the object of research over the last decades. However, there is a lack of information on the effects induced by the heavy ion component of cosmic rays in the electronic energy loss regime. The aim of the present work is to simulate of the astrophysical environment where ice mantles are exposed to the heavy ion cosmic ray irradiation. Sample ice films at 13K were irradiated by nickel ions with energies in the 1-10 MeV/u range and analyzed by means of FTIR spectrometry. Nickel ions were used because their energy deposition is similar to that deposited by iron ions, which are particularly abundant cosmic rays amongst the heaviest ones. In this work the effects caused by nickel ions on condensed gases are studied (destruction and production of molecules as well as associated cross sections, sputtering yields) and compared with respective values for light ions and UV photons.

  5. Vitamin E Analogs as Radiation Response Modifiers

    PubMed Central

    Singh, Pankaj K.; Krishnan, Sunil

    2015-01-01

    The potentially life-threatening effects of total body ionizing radiation exposure have been known for more than a century. Despite considerable advances in our understanding of the effects of radiation over the past six decades, efforts to identify effective radiation countermeasures for use in case of a radiological/nuclear emergency have been largely unsuccessful. Vitamin E is known to have antioxidant properties capable of scavenging free radicals, which have critical roles in radiation injuries. Tocopherols and tocotrienols, vitamin E analogs together known as tocols, have shown promise as radioprotectors. Although the pivotal mechanisms of action of tocols have long been thought to be their antioxidant properties and free radical scavenging activities, other alternative mechanisms have been proposed to drive their activity as radioprotectors. Here we provide a brief overview of the effects of ionizing radiation, the mechanistic mediators of radiation-induced damage, and the need for radiation countermeasures. We further outline the role for, efficacy of, and mechanisms of action of tocols as radioprotectors, and we compare and contrast their efficacy and mode of action with that of another well-studied chemical radioprotector, amifostine. PMID:26366184

  6. Interstellar and Planetary Analogs in the Laboratory

    NASA Technical Reports Server (NTRS)

    Salama, Farid

    2013-01-01

    We present and discuss the unique capabilities of the laboratory facility, COSmIC, that was developed at NASA Ames to investigate the interaction of ionizing radiation (UV, charged particles) with molecular species (neutral molecules, radicals and ions) and carbonaceous grains in the Solar System and in the Interstellar Medium (ISM). COSmIC stands for Cosmic Simulation Chamber, a laboratory chamber where interstellar and planetary analogs are generated, processed and analyzed. It is composed of a pulsed discharge nozzle (PDN) expansion that generates a free jet supersonic expansion in a plasma cavity coupled to two ultrahigh-sensitivity, complementary in situ diagnostics: a cavity ring down spectroscopy (CRDS) system for photonic detection and a Reflectron time-of-flight mass spectrometer (ReTOF-MS) for mass detection. This setup allows the study of molecules, ions and solids under the low temperature and high vacuum conditions that are required to simulate some interstellar, circumstellar and planetary physical environments providing new fundamental insights on the molecular level into the processes that are critical to the chemistry in the ISM, circumstellar and planet forming regions, and on icy objects in the Solar System. Recent laboratory results that were obtained using COSmIC will be discussed, in particular the progress that have been achieved in monitoring in the laboratory the formation of solid particles from their gas-phase molecular precursors in environments as varied as circumstellar outflow and planetary atmospheres.

  7. [Petrological Analysis of Astrophysical Dust Analog Evolution

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1997-01-01

    This project "Petrological analysis of astrophysical dust analog evolution" was initiated to try to understand the vapor phase condensation, and the nature of the reaction products, in circumstellar environments, such as the solar nebula 4,500 Myrs ago, and in the interstellar medium. Telescope-based infrared [IR] spectroscopy offers a broad-scale inventory of the various types of dust in these environments but no details on small-scale variations in terms of chemistry and morphology and petrological phase relationships. Vapor phase condensation in these environments is almost certainly a non-equilibrium process. The main challenge to this research was to document the nature of this process that, based on astrophysical observations, seems to yield compositionally consistent materials. This observation may suggest a predictable character during non-equilibrium condensation. These astrophysical environments include two chemically distinct, that is, oxygen-rich and carbon-rich environments. The former is characterized by silicates the latter by carbon-bearing solids. According to cosmological models of stellar evolution circumstellar dust accreted into protoplanets wherein thermal and/or aqueous processes will alter the dust under initially, non-equilibrium conditions.

  8. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, M.M.; Shoup, T.

    1998-09-15

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

  9. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, Mark M.; Shoup, Timothy

    1998-10-06

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

  10. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, M.M.; Shoup, T.

    1998-10-06

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

  11. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, Mark M.; Shoup, Timothy

    1998-09-15

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

  12. HERE, THERE, AND EVERYWHEREPublic Science Through Analogy

    NASA Astrophysics Data System (ADS)

    Arcand, Kimberly K.

    2014-06-01

    Here, There, and Everywhere (HTE) is a program that consists of a series of exhibitions, posters, and supporting hands-on activities that utilize analogies in the teaching of science, engineering, and technology to provide multi-generational and family-friendly content in English and Spanish to small community centers, libraries, under-resourced small science centers. The purpose of the program is to connect crosscutting science content (in Earth, atmospheric and planetary sciences and astrophysics) with everyday phenomena. By using different modes of content delivery, from physical exhibits and handouts,to interpretive stations, facilitated activities for educators, and online resources, HTE helps to demonstrate the universality of physical laws and the connection between our everyday world and the universe as a whole to members of the public who may not identify strongly with science. HTE is part of a series of public science projects created and developed by the Education and Public Outreach group at the Chandra X-ray Center. The authors discuss how HTE fits into the lineage of public science outreach that aims to engage the greater public in non-traditional venues for science learning and appreciation, as well as what might be learned about the participants of such projects.

  13. The halogen analogs of thiolated gold nanoclusters

    SciTech Connect

    Jiang, Deen; Walter, Michael

    2012-01-01

    Is it possible to replace all the thiolates in a thiolated gold nanocluster with halogens while still maintaining the geometry and the electronic structure? In this work, we show from density functional theory that such halogen analogs of thiolated gold nanoclusters are highly likely. Using Au{sub 25}X{sub 18}{sup -} as an example, where X = F, Cl, Br, or I replaces -SR, we find that Au{sub 25}Cl{sub 18}{sup -} demonstrates a high similarity to Au{sub 25}(SR){sub 18}{sup -} by showing Au-Cl distances, Cl-Au-Cl angles, band gap, and frontier orbitals similar to those in Au{sub 25}(SR){sub 18}{sup -}. DFT-based global minimization also indicates the energetic preference of staple formation for the Au{sub 25}Cl{sub 18}{sup -} cluster. The similarity between Au{sub m}(SR){sub n} and Au{sub m}X{sub n} could be exploited to make viable Au{sub m}X{sub n} clusters and to predict structures for Au{sub m}(SR){sub n}.

  14. Applying analog integrated circuits for HERO protection

    NASA Technical Reports Server (NTRS)

    Willis, Kenneth E.; Blachowski, Thomas J.

    1994-01-01

    One of the most efficient methods for protecting electro-explosive devices (EED's) from HERO and ESD is to shield the EED in a conducting shell (Faraday cage). Electrical energy is transferred to the bridge by means of a magnetic coupling which passes through a portion of the conducting shell that is made from a magnetically permeable but electrically conducting material. This technique was perfected by ML Aviation, a U.K. company, in the early 80's, and was called a Radio Frequency Attenuation Connector (RFAC). It is now in wide use in the U.K. Previously, the disadvantage of RFAC over more conventional methods was its relatively high cost, largely driven by a thick film hybrid circuit used to switch the primary of the transformer. Recently, through a licensing agreement, this technology has been transferred to the U.S. and significant cost reductions and performance improvements have been achieved by the introduction of analog integrated circuits. An integrated circuit performs the following functions: (1) Chops the DC input to a signal suitable for driving the primary of the transformer; (2) Verifies the input voltage is above a threshold; (3) Verifies the input voltage is valid for a pre set time before enabling the device; (4) Provides thermal protection of the circuit; and (5) Provides an external input for independent logic level enabling of the power transfer mechanism. This paper describes the new RFAC product and its applications.

  15. Somatostatin analog treatment of acromegaly: new aspects.

    PubMed

    Lamberts, S W; del Pozo, E

    1988-01-01

    Ten acromegalics received daily doses of 200-300 micrograms of a long-acting somatostatin analog, SMS 201-995 (Sandostatin, SMS), for an average of 64 weeks. Basal mean GH values of 44 +/- (SE) 7.8 ng/ml had fallen into the normal range at the end of the observation period (mean 64 weeks). This effect was accompanied by a substantial drop in somatomedin-C values. Reduction of pituitary tumor size could be documented in 3 of 6 patients. Whereas SMS did not affect high plasma PRL in 4 microprolactinoma patients, lactotrophs turned sensitive to this agent in mixed GH/PRL tumors. In a comparative study between SMS and bromocriptine, the former normalized circulating GH in 10 of 17 acromegalics in an acute trial, whereas bromocriptine was effective in only 5. A combination of both substances was effective in 2 of 3 patients who were insensitive to single drug administration. Cultures of GH-secreting tumor cells showed a statistically significant hormone decrease in the medium when exposed to SMS. However, in some instances, a diminution of the GH contents of the tumor cells was also observed, presumably as the basis for intracellular breakdown and clinical tumor shrinkage.

  16. Thermal Conductivity Measurements on consolidated Soil Analogs

    NASA Astrophysics Data System (ADS)

    Seiferlin, K.; Heimberg, M.; Thomas, N.

    2007-08-01

    Heat transport in porous media such as soils and regolith is significantly reduced compared to the properties of compact samples of the same material. The bottle neck for solid state heat transport is the contact area between adjacent grains. For "dry" and unconsolidated materials the contact areas and thus the thermal conductivity are extremely small. Sintering and cementation are two processes that can increase the cross section of interstitial bonds signifcantly. On Mars, cementation can be caused by condensation of water or carbon dioxide ice from the vapor phase, or from salts and minerals that fall out from aqueous solutions. We produced several artificially cemented samples, using small glass beads of uniform size as soil analog. The cementation is achieved by initially molten wax that is mixed with the glass beads while liqiud. The wax freezes preferably at the contact points between grains, thus minimizing surface energy, and consolidates the samples. The thermal conductivity of these samples is then measured in vacuum. We present the results of these measurements and compare them with theoretical models. The observed range of thermal conductivity values can explain some, but not all of the variations in thermal intertia that can be seen in TES remote sensing data.

  17. Semantics by analogy for illustrative volume visualization☆

    PubMed Central

    Gerl, Moritz; Rautek, Peter; Isenberg, Tobias; Gröller, Eduard

    2012-01-01

    We present an interactive graphical approach for the explicit specification of semantics for volume visualization. This explicit and graphical specification of semantics for volumetric features allows us to visually assign meaning to both input and output parameters of the visualization mapping. This is in contrast to the implicit way of specifying semantics using transfer functions. In particular, we demonstrate how to realize a dynamic specification of semantics which allows to flexibly explore a wide range of mappings. Our approach is based on three concepts. First, we use semantic shader augmentation to automatically add rule-based rendering functionality to static visualization mappings in a shader program, while preserving the visual abstraction that the initial shader encodes. With this technique we extend recent developments that define a mapping between data attributes and visual attributes with rules, which are evaluated using fuzzy logic. Second, we let users define the semantics by analogy through brushing on renderings of the data attributes of interest. Third, the rules are specified graphically in an interface that provides visual clues for potential modifications. Together, the presented methods offer a high degree of freedom in the specification and exploration of rule-based mappings and avoid the limitations of a linguistic rule formulation. PMID:23576827

  18. Weathering of Mars - Antarctic analog studies

    NASA Technical Reports Server (NTRS)

    Berkley, J. L.; Drake, M. J.

    1981-01-01

    Subaerial extrusion of lavas above permafrost is proposed as a possible weathering regime leading to the presence of Martian surface fines, and the characteristics of this process are examined through a study of the analogous altered terrestrial basalts from Antarctica. On the basis of mineralogical and petrological analyses of samples obtained from core cuttings recovered by the Dry Valley Drilling Program from rocks predominantly of an aklalic basalt-phonolite suite, it is found that in the absence of liquid water, weathering is geologically slow, and that zeolites predominate over clays as secondary mineral. Of the possible weathering processes proposed for Mars, it is concluded that both subaerial extrusion and subpermafrost intrusion of lavas involving liquid water would be less important volumetrically than the hydrothermal alteration of impact melt sheets if water were present during an intense phase of early bombardment, or than subsequent solid-gas alteration reactions. It is thus predicted that the present Martian fines should contain a major contribution from the ancient crust as typified by the southern cratered highlands, and a lesser contribution from the younger basaltic lavas.

  19. Serial Pixel Analog-to-Digital Converter

    SciTech Connect

    Larson, E D

    2010-02-01

    This method reduces the data path from the counter to the pixel register of the analog-to-digital converter (ADC) from as many as 10 bits to a single bit. The reduction in data path width is accomplished by using a coded serial data stream similar to a pseudo random number (PRN) generator. The resulting encoded pixel data is then decoded into a standard hexadecimal format before storage. The high-speed serial pixel ADC concept is based on the single-slope integrating pixel ADC architecture. Previous work has described a massively parallel pixel readout of a similar architecture. The serial ADC connection is similar to the state-of-the art method with the exception that the pixel ADC register is a shift register and the data path is a single bit. A state-of-the-art individual-pixel ADC uses a single-slope charge integration converter architecture with integral registers and “one-hot” counters. This implies that parallel data bits are routed among the counter and the individual on-chip pixel ADC registers. The data path bit-width to the pixel is therefore equivalent to the pixel ADC bit resolution.

  20. The MARS2013 Mars analog mission.

    PubMed

    Groemer, Gernot; Soucek, Alexander; Frischauf, Norbert; Stumptner, Willibald; Ragonig, Christoph; Sams, Sebastian; Bartenstein, Thomas; Häuplik-Meusburger, Sandra; Petrova, Polina; Evetts, Simon; Sivenesan, Chan; Bothe, Claudia; Boyd, Andrea; Dinkelaker, Aline; Dissertori, Markus; Fasching, David; Fischer, Monika; Föger, Daniel; Foresta, Luca; Fritsch, Lukas; Fuchs, Harald; Gautsch, Christoph; Gerard, Stephan; Goetzloff, Linda; Gołebiowska, Izabella; Gorur, Paavan; Groemer, Gerhard; Groll, Petra; Haider, Christian; Haider, Olivia; Hauth, Eva; Hauth, Stefan; Hettrich, Sebastian; Jais, Wolfgang; Jones, Natalie; Taj-Eddine, Kamal; Karl, Alexander; Kauerhoff, Tilo; Khan, Muhammad Shadab; Kjeldsen, Andreas; Klauck, Jan; Losiak, Anna; Luger, Markus; Luger, Thomas; Luger, Ulrich; McArthur, Jane; Moser, Linda; Neuner, Julia; Orgel, Csilla; Ori, Gian Gabriele; Paternesi, Roberta; Peschier, Jarno; Pfeil, Isabella; Prock, Silvia; Radinger, Josef; Ramirez, Barbara; Ramo, Wissam; Rampey, Mike; Sams, Arnold; Sams, Elisabeth; Sandu, Oana; Sans, Alejandra; Sansone, Petra; Scheer, Daniela; Schildhammer, Daniel; Scornet, Quentin; Sejkora, Nina; Stadler, Andrea; Stummer, Florian; Taraba, Michael; Tlustos, Reinhard; Toferer, Ernst; Turetschek, Thomas; Winter, Egon; Zanella-Kux, Katja

    2014-05-01

    We report on the MARS2013 mission, a 4-week Mars analog field test in the northern Sahara. Nineteen experiments were conducted by a field crew in Morocco under simulated martian surface exploration conditions, supervised by a Mission Support Center in Innsbruck, Austria. A Remote Science Support team analyzed field data in near real time, providing planning input for the management of a complex system of field assets; two advanced space suit simulators, four robotic vehicles, an emergency shelter, and a stationary sensor platform in a realistic work flow were coordinated by a Flight Control Team. A dedicated flight planning group, external control centers for rover tele-operations, and a biomedical monitoring team supported the field operations. A 10 min satellite communication delay and other limitations pertinent to human planetary surface activities were introduced. The fields of research for the experiments were geology, human factors, astrobiology, robotics, tele-science, exploration, and operations research. This paper provides an overview of the geological context and environmental conditions of the test site and the mission architecture, in particular the communication infrastructure emulating the signal travel time between Earth and Mars. We report on the operational work flows and the experiments conducted, including a deployable shelter prototype for multiple-day extravehicular activities and contingency situations. PMID:24823799

  1. Phonon analog of topological nodal semimetals

    NASA Astrophysics Data System (ADS)

    Po, Hoi Chun; Bahri, Yasaman; Vishwanath, Ashvin

    2016-05-01

    Topological band structures in electronic systems like topological insulators and semimetals give rise to highly unusual physical properties. Analogous topological effects have also been discussed in bosonic systems, but the novel phenomena typically occur only when the system is excited by finite-frequency probes. A mapping recently proposed by C. L. Kane and T. C. Lubensky [Nat. Phys. 10, 39 (2014), 10.1038/nphys2835], however, establishes a closer correspondence. It relates the zero-frequency excitations of mechanical systems to topological zero modes of fermions that appear at the edges of an otherwise gapped system. Here we generalize the mapping to systems with an intrinsically gapless bulk. In particular, we construct mechanical counterparts of topological semimetals. The resulting gapless bulk modes are physically distinct from the usual acoustic Goldstone phonons and appear even in the absence of continuous translation invariance. Moreover, the zero-frequency phonon modes feature adjustable momenta and are topologically protected as long as the lattice coordination is unchanged. Such protected soft modes with tunable wave vector may be useful in designing mechanical structures with fault-tolerant properties.

  2. Using Analogies to Prevent Misconceptions about Chemical Equilibrium

    ERIC Educational Resources Information Center

    Sahin Pekmez, Esin

    2010-01-01

    The main purpose of this study was to find the effectiveness of using analogies to prevent misconceptions about chemical equilibrium. Nineteen analogies, which were based on dynamic aspects of chemical equilibrium and application of Le Chatelier's principle, were developed. The participations of this study consisted of 11th grade students (n: 151)…

  3. Analysis of Attention and Analogical Reasoning in Children of Poverty

    ERIC Educational Resources Information Center

    Weatherholt, Tara N.; Harris, Ruby C.; Burns, Barbara M.; Clement, Catherine

    2006-01-01

    This study examined the relationship between specific attentional aspects of processing capacity and analogical reasoning in children from low-income families. 77 children aged 48-77 (M = 56.7) months were assessed on an analogical reasoning task (matrices subtest of the Kaufman Brief Intelligence Test) and on computerized attention tasks designed…

  4. Using Analogies to Improve the Teaching Performance of Preservice Teachers

    ERIC Educational Resources Information Center

    James, Mark C.; Scharmann, Lawrence C.

    2007-01-01

    Prior research in both education and cognitive science has identified analogy making as a powerful tool for explanation as well as a fundamental mechanism for facilitating an individual's construction of knowledge. While a considerable body of research exists focusing on the role analogy plays in learning science concepts, relatively little is…

  5. The interplay of conflict and analogy in multidisciplinary teams.

    PubMed

    Paletz, Susannah B F; Schunn, Christian D; Kim, Kevin H

    2013-01-01

    Creative teamwork in multidisciplinary teams is a topic of interest to cognitive psychologists on the one hand, and to both social and organizational psychologists on the other. However, the interconnections between cognitive and social layers have been rarely explored. Drawing on mental models and dissonance theories, the current study takes a central variable studied by cognitive psychologists-analogy-and examines its relationship to a central variable examined by social psychologists-conflict. In an observational, field study, over 11h of audio-video data from conversations of the Mars Exploration Rover scientists were coded for different types of analogy and micro-conflicts that reveal the character of underlying psychological mechanisms. Two different types of time-lagged logistic models applied to these data revealed asymmetric patterns of associations between analogy and conflict. Within-domain analogies, but not within-discipline or outside-discipline analogies, preceded science and work process conflicts, suggesting that in multidisciplinary teams, representational gaps in very close domains will be more likely to spark conflict. But analogies also occurred in reaction to conflict: Process and negative conflicts, but not task conflicts, preceded within-discipline analogies, but not to within-domain or outside-discipline analogies. This study demonstrates ways in which cognition can be bidirectionally tied to social processes and discourse. PMID:22980920

  6. Introducing Analog Drawing into a Prison Art Education Setting.

    ERIC Educational Resources Information Center

    Yesh, Patrick

    A qualitative research study documents the progress of an adult male art student enrolled in a grade nine art class of adult males in a federal, maximum security penitentiary. Analog drawings were used as part of the curriculum. An analog drawing is a symbolic drawing expressing one's emotions, ideas, and feelings, often used to identify and help…

  7. The Occurrence of Analogies in Elementary School Science Books.

    ERIC Educational Resources Information Center

    Newton, Lynn D.

    2003-01-01

    Investigates the extent to which analogies in instructional science books are provided by authors. Eighty texts available from commercial publishers and intended for use in the elementary school classroom were analyzed. It was found that most of the books did not offer many analogies and fewer than those for older students. (Contains 49…

  8. Where Concepts Meet Percepts: Stimulating Analogical Thought in Children.

    ERIC Educational Resources Information Center

    Flick, Larry

    1991-01-01

    Reports an instructional application of a theory of analogical reasoning. Uses the grinding of a sugar cube as an explanatory-predictive analogy for state transitions of water as a stimulus for promoting associations with other appropriate experiences in elementary school students. (PR)

  9. Analogical Reasoning in the Classroom: Insights from Cognitive Science

    ERIC Educational Resources Information Center

    Vendetti, Michael S.; Matlen, Bryan J.; Richland, Lindsey E.; Bunge, Silvia A.

    2015-01-01

    Applying knowledge from one context to another is a notoriously difficult problem, both for children and adults, but lies at the heart of educational endeavors. Analogical reasoning is a cognitive underpinning of the ability to notice and draw similarities across contexts. Reasoning by analogy is especially challenging for students, who must…

  10. The Effectiveness of Teaching Science with Pictorial Analogies.

    ERIC Educational Resources Information Center

    Lin, Huann-shyang; And Others

    1996-01-01

    This study uses a conceptual problem-solving test to investigate the effect of a series of pictorial analogies on the concepts of density, pressure, and atmospheric pressure in Year Eight classrooms. Findings indicate that students taught with the pictorial analogies scored significantly higher than their counterparts. Low achievers were the most…

  11. Using Self-Generated Analogies in Teaching of Thermodynamics

    ERIC Educational Resources Information Center

    Haglund, Jesper; Jeppsson, Fredrik

    2012-01-01

    Using self-generated analogies has been proposed as a method in a constructivist tradition for students to learn about a new subject, by use of what they previously know. We report on a group exercise on using self-generated analogies to make sense of two thermodynamic processes, reversible adiabatic expansion and free adiabatic expansion of an…

  12. Exploring the Impacts of Analogies on Computer Hardware

    ERIC Educational Resources Information Center

    Dincer, Serkan

    2011-01-01

    In the last few decades, analogy, which is considered as a special case for reasoning, has attracted a great deal of attention from cognitive scientists. Although analogy was rarely applied in previous decades, now it is often considered by educators and researchers as a strategy to provide creative solutions and poetic writing (Paris & Glynn,…

  13. Using Analogies to Overcome Misconceptions: A Technology Course Example.

    ERIC Educational Resources Information Center

    Gokhale, Anu A.

    1996-01-01

    Both a control group and experimental group (23 students each) received a lecture on direct current circuits; the experimental group also participated in a lab using a device explaining an analogy for electric current. The experimental group's posttest scores were much higher, indicating that the analogical device helped overcome student…

  14. Using Analogy to Overcome Misconceptions about Conservation of Matter.

    ERIC Educational Resources Information Center

    Stavy, Ruth

    1991-01-01

    This study (n=192) examined the use of analogical instruction to overcome misconceptions about conservation of matter. Students who understood the concept conservation of matter when iodine was evaporated were able to transfer their understanding to the evaporation of acetone. This indicates that teaching by analogy can be an effective tool in…

  15. Protocol Analysis of Aptitude Differences in Figural Analogy Problem Representation.

    ERIC Educational Resources Information Center

    Schiano, Diane J.

    Individual differences in performance on figural analogy tests are usually attributed to quantitative differences in processing parameters rather than to qualitative differences in the formation and use of representations. Yet aptitude-related differences in categorizing standardized figural analogy problems between high and low scorers have been…

  16. Pictorial Analogies XI: Concentrations and Acidity of Solutions.

    ERIC Educational Resources Information Center

    Fortman, John J.

    1994-01-01

    Presents pictorial analogies of several concepts relating to solutions for chemistry students. These include concentration of solution, strength of solution, supersaturated solution, and conjugate acid-base pairs. Among the examples are comparison of acid strength to percentage of strong soldiers or making supersaturated solution analogous to a…

  17. Implementation Alternatives to Analog Graphic Function Generation: Some Examples.

    ERIC Educational Resources Information Center

    Karayanakis, Nicholas M.

    1988-01-01

    This paper discusses the mechanization of mathematical functions by means of analog electronics. Five different approaches are described which demonstrate the versatility of the analog technique by using parabolic function, exponential decay technique, projectile trajectory, trigonometry, and piecewise linear approximation techniques. (YP)

  18. The interplay of conflict and analogy in multidisciplinary teams.

    PubMed

    Paletz, Susannah B F; Schunn, Christian D; Kim, Kevin H

    2013-01-01

    Creative teamwork in multidisciplinary teams is a topic of interest to cognitive psychologists on the one hand, and to both social and organizational psychologists on the other. However, the interconnections between cognitive and social layers have been rarely explored. Drawing on mental models and dissonance theories, the current study takes a central variable studied by cognitive psychologists-analogy-and examines its relationship to a central variable examined by social psychologists-conflict. In an observational, field study, over 11h of audio-video data from conversations of the Mars Exploration Rover scientists were coded for different types of analogy and micro-conflicts that reveal the character of underlying psychological mechanisms. Two different types of time-lagged logistic models applied to these data revealed asymmetric patterns of associations between analogy and conflict. Within-domain analogies, but not within-discipline or outside-discipline analogies, preceded science and work process conflicts, suggesting that in multidisciplinary teams, representational gaps in very close domains will be more likely to spark conflict. But analogies also occurred in reaction to conflict: Process and negative conflicts, but not task conflicts, preceded within-discipline analogies, but not to within-domain or outside-discipline analogies. This study demonstrates ways in which cognition can be bidirectionally tied to social processes and discourse.

  19. MALISAM: a database of structurally analogous motifs in proteins.

    PubMed

    Cheng, Hua; Kim, Bong-Hyun; Grishin, Nick V

    2008-01-01

    MALISAM (manual alignments for structurally analogous motifs) represents the first database containing pairs of structural analogs and their alignments. To find reliable analogs, we developed an approach based on three ideas. First, an insertion together with a part of the evolutionary core of one domain family (a hybrid motif) is analogous to a similar motif contained within the core of another domain family. Second, a motif at an interface, formed by secondary structural elements (SSEs) contributed by two or more domains or subunits contacting along that interface, is analogous to a similar motif present in the core of a single domain. Third, an artificial protein obtained through selection from random peptides or in sequence design experiments not biased by sequences of a particular homologous family, is analogous to a structurally similar natural protein. Each analogous pair is superimposed and aligned manually, as well as by several commonly used programs. Applications of this database may range from protein evolution studies, e.g. development of remote homology inference tools and discriminators between homologs and analogs, to protein-folding research, since in the absence of evolutionary reasons, similarity between proteins is caused by structural and folding constraints. The database is publicly available at http://prodata.swmed.edu/malisam. PMID:17855399

  20. Using Gravitational Analogies to Introduce Elementary Electrical Field Theory Concepts

    ERIC Educational Resources Information Center

    Saeli, Susan; MacIsaac, Dan

    2007-01-01

    Since electrical field concepts are usually unfamiliar, abstract, and difficult to visualize, conceptual analogies from familiar gravitational phenomena are valuable for teaching. Such analogies emphasize the underlying continuity of field concepts in physics and support the spiral development of student understanding. We find the following four…

  1. Use of Analogy in Learning Physics: The Role of Representations

    ERIC Educational Resources Information Center

    Podolefsky, Noah S.; Finkelstein, Naoh D.

    2006-01-01

    Previous studies have demonstrated that analogies can promote student learning in physics and can be productively taught to students to support their learning, under certain conditions. We build on these studies to explore the use of analogy by students in a large introductory college physics course. In the first large-scale study of its kind, we…

  2. Generation of Spontaneous Analogies by Students Solving Science Problems.

    ERIC Educational Resources Information Center

    Clement, John

    In this study 34 spontaneous analogies produced by 16 college freshmen while solving qualitative physics problems are analyzed. A number of the analogies were invalid in the sense that they led to an incorrect answer from the physicist's point of view. However, many were valid, and a few were powerful in the sense that they seemed not only to help…

  3. 47 CFR 74.705 - TV broadcast analog station protection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false TV broadcast analog station protection. 74.705... EXPERIMENTAL RADIO, AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.705 TV broadcast analog station protection. (a) The TV...

  4. 47 CFR 74.705 - TV broadcast analog station protection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false TV broadcast analog station protection. 74.705... EXPERIMENTAL RADIO, AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.705 TV broadcast analog station protection. (a) The TV...

  5. Molecular interactions between (-)-epigallocatechin gallate analogs and pancreatic lipase.

    PubMed

    Wang, Shihui; Sun, Zeya; Dong, Shengzhao; Liu, Yang; Liu, Yun

    2014-01-01

    The molecular interactions between pancreatic lipase (PL) and four tea polyphenols (EGCG analogs), like (-)-epigallocatechin gallate (EGCG), (-)-gallocatechin gallate (GCG), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin (EC), were studied from PL activity, conformation, kinetics and thermodynamics. It was observed that EGCG analogs inhibited PL activity, and their inhibitory rates decreased by the order of EGCG>GCG>ECG>EC. PL activity at first decreased rapidly and then slowly with the increase of EGCG analogs concentrations. α-Helix content of PL secondary structure decreased dependent on EGCG analogs concentration by the order of EGCG>GCG>ECG>EC. EGCG, ECG, and EC could quench PL fluorescence both dynamically and statically, while GCG only quenched statically. EGCG analogs would induce PL self-assembly into complexes and the hydrodynamic radii of the complexes possessed a close relationship with the inhibitory rates. Kinetics analysis showed that EGCG analogs non-competitively inhibited PL activity and did not bind to PL catalytic site. DSC measurement revealed that EGCG analogs decreased the transition midpoint temperature of PL enzyme, suggesting that these compounds reduced PL enzyme thermostability. In vitro renaturation through urea solution indicated that interactions between PL and EGCG analogs were weak and non-covalent. PMID:25365042

  6. Resistance to somatostatin analogs in acromegaly: an evolving concept?

    PubMed

    Gola, M; Bonadonna, S; Mazziotti, G; Amato, G; Giustina, A

    2006-01-01

    The aim of acromegaly treatment is to control the disease by suppressing GH hyperactivity and reducing the size or impeding the growth of the pituitary GH secreting mass. Over recent years, many studies have emphasized the role of SS analogs in the treatment of acromegaly. In fact, SS analogs have been demonstrated to be an effective tool not only in the control of GH hypersecretion but also more recently in the control of tumor growth, in a relevant number of acromegalic patients both as primary or adjunctive treatment. In this context, the therapeutic failure of medical treatment with SS analogs needs to be accurately defined particularly when they are used as primary treatment but also when they are given to patients previously operated upon, since other effective therapeutic options are nowadays available. Current definition of resistance to SS analogs is based on their efficacy to control GH and IGF-I. However, due to the emerging significance of the shrinkage effect of SS analogs on pituitary adenomas as well as to the apparent dissociation between this effect and the biochemical effects of treatment with these analogs, an evolution in the concept of SS resistance is likely to be occurring. In this review, we will discuss the biological basis of the discordance between biochemical and volumetric effects of SS analogs, and we will address the intriguing clinical and therapeutic aspects related to a possible redefinition of the resistance to SS analogs. PMID:16553040

  7. Self-Generated Analogical Models of Respiratory Pathways

    ERIC Educational Resources Information Center

    Lee, Yeung Chung

    2015-01-01

    Self-generated analogical models have emerged recently as alternatives to teacher-supplied analogies and seem to have good potential to promote deep learning and scientific thinking. However, studies of the ways and contexts in which students generate these models are still too limited to allow a fuller appraisal of these models' effectiveness in…

  8. The Impact of Analogy on L3 Reading Comprehension

    ERIC Educational Resources Information Center

    Karami, Hossein; Nodoushan, Mohammad Ali Salmani

    2014-01-01

    Little research has been conducted to investigate the effect of analogy on third language (L3, hereafter) reading comprehension though some experts believe that it has facilitating and debilitating effects on L1 and L2 respectively. This article explores the effect of analogies on reading comprehension of expository texts by students of English as…

  9. Hardware implementation of a discrete-time analog adaptive filter

    SciTech Connect

    Donohoe, G.W.

    1981-01-01

    This paper describes a hardware implementation of a discrete-time adaptive filter using a bucket-brigade device (BBD) tapped analog delay line, analog voltage multipliers and operational amplifier integrators and summing circuits. Some design considerations for this class of circuits are discussed.

  10. Young Children's Analogical Problem Solving: Gaining Insights from Video Displays

    ERIC Educational Resources Information Center

    Chen, Zhe; Siegler, Robert S.

    2013-01-01

    This study examined how toddlers gain insights from source video displays and use the insights to solve analogous problems. Two- to 2.5-year-olds viewed a source video illustrating a problem-solving strategy and then attempted to solve analogous problems. Older but not younger toddlers extracted the problem-solving strategy depicted in the video…

  11. Azastilbene Analogs as Tyrosinase Inhibitors: New Molecules with Depigmenting Potential

    PubMed Central

    Lima, Larissa Lavorato; Lima, Rebeca Mól; da Silva, Annelisa Farah; do Carmo, Antônio Márcio Resende; da Silva, Adilson David; Raposo, Nádia Rezende Barbosa

    2013-01-01

    This research has been an effort to develop synthetic resveratrol analogs in order to improve the depigmenting potential of natural resveratrol. Six resveratrol analogs were synthesized and tested for tyrosinase inhibitory activity in vitro, by qualitative and quantitative steps. The results showed the analog C as being the most powerful tyrosinase inhibitor (IA50 = 65.67 ± 0.60 μg/mL), followed by the analogs B, E, F, A, and D, respectively. The analog C presented a tyrosinase inhibition potential better than natural resveratrol (P < 0.001). The best depigmenting activity was provided by the presence of hydroxyl in the orthoposition on the second phenolic ring. PMID:23476126

  12. NASA HRP Immunology Discipline - Use of Terrestrial Analogs

    NASA Technical Reports Server (NTRS)

    Crucian, Brian

    2014-01-01

    Due to the cost and operational constraints, as well as technical implementation limitations, it is desirous to perform relevant space physiology investigations first in terrestrial 'space analogs'. This is particularly true for initial investigations, which may then provide appropriate focus for subsequent flight investigations, or for mechanistic investigations that simply cannot be performed during spaceflight. Appropriate analog choice is extremely important. There are a wide variety of terrestrial space analogs, each relevant to a particular physiological discipline (or disciplines) and each with a particular fidelity (or lack thereof) to spaceflight, and each with unique operational constraints. The HRP Immunology Discipline is tasked with managing the HRP Risk concerning clinical risk for Astronaut crews related to spaceflight-associated immune dysregulation. Such dysregulation has been documented to occur during spaceflight, and found to persist for the duration of a 6-month ISS mission. Studies continue to characterize the onorbit phenomenon, but it generally consists of diminished immunocyte function, dysregulated cytokine profiles, and persistent herpesvirus reactivation. Causes are thought to synergistically include microgravity, psychological or physiological stress, radiation, and/or circadian misalignment. An appropriate terrestrial analog for immune dysregulation would replicate as many of these influences as possible. Such analogs may include clinostat or bioreactor cell culture (microgravity), hindlimb suspension (stress, fluid shifts, hypokinesis), or human deployment to remote or extreme environments (isolation, stress, circadian). Also, the laboratory setting may be used as an analog, or to augment analogs, such as sleep deprivation/misalignment or human centrifugation to replicate gravitational stress. As an appropriate example of a NASA Disciplines use of Terrestrial space analogs, this talk will discuss spaceflight associated immune

  13. Learning Plate Tectonics Using a Pre-Analogy Step

    NASA Astrophysics Data System (ADS)

    Glesener, G. B.; Sandoval, W. A.

    2011-12-01

    Previous research has shown that children tend to demonstrate lower performance on analogical reasoning tasks at a causal relations level compared to most adults (Gentner & Toupin, 1986). This tendency is an obstacle that geoscience educators must overcome because of the high frequency of analogies used in geoscience pedagogy. In particular, analog models are used to convey complex systems of non-everyday/non-observable events found in nature, such as plate tectonics. Key factors in successful analogical reasoning that have been suggested by researchers include knowledge of the causal relations in the base analog (Brown & Kane, 1988; Gentner, 1988; Gentner & Toupin, 1986), and development of learning strategies and metaconceptual competence(Brown & Kane, 1988). External factors, such as guiding cues and hints have been useful cognitive supports that help students reason through analogical problems (Gick & Holyoak, 1980). Cognitive supports have been seen by researchers to decrease processing demands on retrieval and working memory (Richland, Zur, & Holyoak, 2007). We observed third and fourth graders learning about plate tectonics beginning with a pre-analogy step-a cognitive support activity a student can do before working with an analogy to understand the target. This activity was designed to aid students in developing their understanding of object attributes and relations within an analog model so that more focus can be placed on mapping the corresponding higher-order relations between the base and target. Students learned targeted concepts of plate tectonics, as measured by pre to post gains on items adapted from the Geosciences Concept Inventory. Analyses of classroom interaction showed that students used the object attributes and higher-order relations highlighted in the pre-analogy activity as resources to reason about plate boundaries and plate movement during earthquakes.

  14. Complex derivatives

    NASA Astrophysics Data System (ADS)

    Battiston, Stefano; Caldarelli, Guido; Georg, Co-Pierre; May, Robert; Stiglitz, Joseph

    2013-03-01

    The intrinsic complexity of the financial derivatives market has emerged as both an incentive to engage in it, and a key source of its inherent instability. Regulators now faced with the challenge of taming this beast may find inspiration in the budding science of complex systems.

  15. O-Methyltransferases Involved in the Biosynthesis of Volatile Phenolic Derivatives in Rose Petals1

    PubMed Central

    Lavid, Noa; Wang, Jihong; Shalit, Moshe; Guterman, Inna; Bar, Einat; Beuerle, Till; Menda, Naama; Shafir, Sharoni; Zamir, Dani; Adam, Zach; Vainstein, Alexander; Weiss, David; Pichersky, Eran; Lewinsohn, Efraim

    2002-01-01

    Rose (Rosa hybrida) flowers produce and emit a diverse array of volatiles, characteristic to their unique scent. One of the most prominent compounds in the floral volatiles of many rose varieties is the methoxylated phenolic derivative 3,5-dimethoxytoluene (orcinol dimethyl ether). Cell-free extracts derived from developing rose petals displayed O-methyltransferase (OMT) activities toward several phenolic substrates, including 3,5-dihydroxytoluene (orcinol), 3-methoxy,5-hydroxytoluene (orcinol monomethyl ether), 1-methoxy, 2-hydroxy benezene (guaiacol), and eugenol. The activity was most prominent in rose cv Golden Gate, a variety that produces relatively high levels of orcinol dimethyl ether, as compared with rose cv Fragrant Cloud, an otherwise scented variety but which emits almost no orcinol dimethyl ether. Using a functional genomics approach, we have identified and characterized two closely related cDNAs from a rose petal library that each encode a protein capable of methylating the penultimate and immediate precursors (orcinol and orcinol monomethyl ether, respectively) to give the final orcinol dimethyl ether product. The enzymes, designated orcinol OMTs (OOMT1 and OOMT2), are closely related to other plant methyltransferases whose substrates range from isoflavones to phenylpropenes. The peak in the levels of OOMT1 and OOMT2 transcripts in the flowers coincides with peak OMT activity and with the emission of orcinol dimethyl ether. PMID:12177504

  16. Analogy between general relativity and electromagnetism for slowly moving particles in weak gravitational fields

    NASA Astrophysics Data System (ADS)

    Harris, Edward G.

    1991-05-01

    Starting from the equations of general relativity, equations similar to those of electromagnetic theory are derived. It is assumed that the particles are slowly moving (v≪c), and the gravitational field is sufficiently weak that nonlinear terms in Einstein's field equations can be neglected. For static fields, the analogy to electrostatics and magnetostatics is very close. Results are compared with those of a previous derivation by Braginsky, Caves, and Thorne [Phys. Rev. D 15, 2047-2068 (1977)]. These results lead to very simple derivations of the Lense-Thirring precession [Phys. Z. 19, 156-163 (1918)] and the spin-curvature force of Papepetrou [Proc. R. Soc. London Ser. A 209, 248-258 (1951)] and Pirani [Acta Phys. Pol. 15, 389-405 (1956)].

  17. The Effect of Analogy-Based Teaching on Students' Achievement and Students' Views about Analogies

    ERIC Educational Resources Information Center

    Genc, Murat

    2013-01-01

    The purpose of this study is to determine the effect of the analogy-based teaching on students' achievement and students' views about analogies. In this research, Solomon group design which is one of the experimental designs, was implemented. The sample of the research consists of 108 students in four 6th grade classes in Turkey. The…

  18. Analogical Matrices in Young Children and Students with Intellectual Disability: Reasoning by Analogy or Reasoning by Association?

    ERIC Educational Resources Information Center

    Denaes, Caroline

    2012-01-01

    Background: Analogical reasoning (AR) is renowned for being a complex activity. Young children tend to reason by association, rather by analogy, and people with intellectual disability present problems of memorization. Both these populations usually show low performances in AR. The present author investigated whether familiar material and external…

  19. Differentiation of Keratinocytes Modulates Skin HPA Analog.

    PubMed

    Wierzbicka, Justyna M; Żmijewski, Michał A; Antoniewicz, Jakub; Sobjanek, Michal; Slominski, Andrzej T

    2017-01-01

    It is well established, that epidermal keratinocytes express functional equivalent of hypothalamus-pituitary-adrenal axis (HPA) in order to respond to changing environment and maintain internal homeostasis. We are presenting data indicating that differentiation of primary neonatal human keratinocytes (HPEKp), induced by prolonged incubation or calcium is accompanied by significant changes in the expression of the elements of skin analog of HPA (sHPA). Expression of CRF, UCN1-3, POMC, ACTH, CRFR1, CRFR2, MC1R, MC2R, and GR (coded by NR3C1 gene) were observed on gene/protein levels along differentiation of keratinocytes in culture with similar pattern seen by immunohistochemistry on full thickness skin biopsies. Expression of CRF was more pronounced in less differentiated keratinocytes, which corresponded to the detection of CRF immunoreactivity preferentially in the stratum basale. POMC expression was enhanced in more differentiated keratinocytes, which corresponded to detection of ACTH immunoreactivity, predominantly in the stratum spinosum and stratum granulosum. Expression of urocortins was also affected by induction of HPEKp differentiation. Immunohistochemical studies showed high prevalence of CRFR1 in well differentiated keratinocytes, while smaller keratinocytes showed predominantly CRFR2 immunoreactivity. MC2R mRNA levels were elevated from days 4 to 8 of in vitro incubation, while MC2R immunoreactivity was the highest in the upper layers of epidermis. Similar changes in mRNA/protein levels of sHPA elements were observed in HPEKp keratinocytes treated with calcium. Summarizing, preferential expression of CRF and POMC (ACTH) by populations of keratinocytes on different stage of differentiation resembles organization of central HPA axis suggesting their distinct role in physiology and pathology of the epidermis. J. Cell. Physiol. 232: 154-166, 2017. © 2016 Wiley Periodicals, Inc.

  20. GnRH analogs in reproductive medicine.

    PubMed

    Hodgen, G D

    1991-03-01

    The uses of gonadotropin releasing hormone (GnRH) analogs in in vitro fertilization (IVF), gamete intrafallopian transfer (GIFT) or related assisted reproductive technologies has advanced rapidly since initial efforts in the early 1980's. By making selective amino acid substitutions, often including the 6 and 10 position, the peptide chemists designed the compounds that we call the GnRH agonists of today. GnRH antagonists possess amino substitutions usually involving positions 1,2,3, 6 and 10, although others may be used. Moreover, recent versions are chemically very sophisticated, often having up to 5 D-amino acids (only L-amino acids occur naturally) and a variety of blocking groups that confer metabolic stability and reduced allergic side-effects. The first available formulation of a GnRH agonist product in the USA was an aqueous preparation for sc injection (usually once or twice daily). It has been studied for several years both in the treatment of prostatic carcinoma and for treatment of children presenting with true precocious puberty. More recently, a depo (monthly) preparation, which microencapulates the GnRH agonist in biodegradable microspheres, received registry approval for treatment of prostatic carcinoma. Also, an implant formulation aimed at chronic treatment indications, as well as nasal delivery products (usually applied multiple times daily) are in development. I will leave specific predictions of the future to those bearing higher powers, except to anticipate that when a safe and effective GnRH antagonist product is developed, it is likely to offer special advantages for IVF/GIFT treatment because of three apparent advantages over GnRH agonist products.