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Sample records for boxes synthesis stability

  1. ESF SOUTH PORTAL BOX-CUT/HIGHWALL STABILITY ANALYSIS (SCPB:N/A)

    SciTech Connect

    Saeed Bonabian

    1996-03-28

    The main purpose and objective of this analysis is to design a Box-Cut at the ESF South Portal to accommodate the Tunnel Boring Machine's (TBM) exit at the conclusion of the ESF Main Loop construction. The stability of the Highwall and the sidewalls at the Box-Cut are assessed using analytical methods by numerical modeling techniques. A ground reinforcement system for the South Ramp Box-Cut slopes will be recommended. This report summarizes the results of the analyses and provides the details of the recommended ground reinforcement system for the Box-Cut slopes at the South Portal. The reinforcement design details are then incorporated into design output documents for implementation in the field. Method of excavation for the Box-Cut is also discussed and a recommendation is provided in this analysis.

  2. Black branes in a box: hydrodynamics, stability, and criticality

    NASA Astrophysics Data System (ADS)

    Emparan, Roberto; Martınez, Marina

    2012-07-01

    We study the effective hydrodynamics of neutral black branes enclosed in a finite cylindrical cavity with Dirichlet boundary conditions. We focus on how the Gregory-Laflamme instability changes as we vary the cavity radius R. Fixing the metric at the cavity wall increases the rigidity of the black brane by hindering gradients of the redshift on the wall. In the effective fluid, this is reflected in the growth of the squared speed of sound. As a consequence, when the cavity is smaller than a critical radius the black brane becomes dynamically stable. The correlation with the change in thermodynamic stability is transparent in our approach. We compute the bulk and shear viscosities of the black brane and find that they do not run with R. We find mean-field theory critical exponents near the critical point.

  3. Synthesis of Bis(1,2-Dimethylimidazole)Copper(I)Hexafluorophosphate: An Experiment Using a Glove Box

    ERIC Educational Resources Information Center

    Niewahner, J. H.; Walters, Keith A.

    2007-01-01

    A detailed description of the synthesis of bis(1,2-dimethylimidazole)copper(I) hexafluorophosphate by using techniques in a glove box is presented. The results shows that the synthesis of the copper complex has a distinct color change indicating by-product oxidation by oxygen.

  4. Box C/D sRNA stem ends act as stabilizing anchors for box C/D di-sRNPs

    PubMed Central

    Yip, W. S. Vincent; Shigematsu, Hideki; Taylor, David W.; Baserga, Susan J.

    2016-01-01

    Ribosomal RNA (rRNA) modifications are essential for ribosome function in all cellular organisms. Box C/D small (nucleolar) ribonucleoproteins [s(no)RNPs] catalyze 2′-O-methylation, one rRNA modification type in Eukarya and Archaea. Negatively stained electron microscopy (EM) models of archaeal box C/D sRNPs have demonstrated the dimeric sRNP (di-sRNP) architecture, which has been corroborated by nuclear magnetic resonance (NMR) studies. Due to limitations of the structural techniques, the orientation of the box C/D sRNAs has remained unclear. Here, we have used cryo-EM to elucidate the sRNA orientation in a M. jannaschii box C/D di-sRNP. The cryo-EM reconstruction suggests a parallel orientation of the two sRNAs. Biochemical and structural analyses of sRNPs assembled with mutant sRNAs indicate a potential interaction between the sRNA stem ends. Our results suggest that the parallel arrangement of the sRNAs juxtaposes their stem ends into close proximity to allow for a stabilizing interaction that helps maintain the di-sRNP architecture. PMID:27342279

  5. Synthesis, hydrolysis and stability of psilocin glucuronide.

    PubMed

    Martin, Rafaela; Schürenkamp, Jennifer; Pfeiffer, Heidi; Lehr, Matthias; Köhler, Helga

    2014-04-01

    A two-step synthesis of psilocin glucuronide (PCG), the main metabolite of psilocin, with methyl 2,3,4-tri-O-isobutyryl-1-O-trichloroacetimidoyl-α-d-glucopyranuronate is reported. With the synthesized PCG, hydrolysis conditions in serum and urine were optimized. Escherichia coli proved to be a better enzyme source for β-glucuronidase than Helix pomatia. It was essential to add ascorbic acid to serum samples to protect psilocin during incubation. Furthermore the stability of PCG and psilocin was compared as stability data are the basis for forensic interpretation of measurements. PCG showed a greater long-term stability after six months in deep frozen serum and urine samples than psilocin. The short-term stability of PCG for one week in whole blood at room temperature and in deep frozen samples was also better than that of psilocin. Therefore, PCG can be considered to be more stable than the labile psilocin and should always be included if psilocin is analyzed in samples. PMID:24513688

  6. Synthesis, hydrolysis and stability of psilocin glucuronide.

    PubMed

    Martin, Rafaela; Schürenkamp, Jennifer; Pfeiffer, Heidi; Lehr, Matthias; Köhler, Helga

    2014-04-01

    A two-step synthesis of psilocin glucuronide (PCG), the main metabolite of psilocin, with methyl 2,3,4-tri-O-isobutyryl-1-O-trichloroacetimidoyl-α-d-glucopyranuronate is reported. With the synthesized PCG, hydrolysis conditions in serum and urine were optimized. Escherichia coli proved to be a better enzyme source for β-glucuronidase than Helix pomatia. It was essential to add ascorbic acid to serum samples to protect psilocin during incubation. Furthermore the stability of PCG and psilocin was compared as stability data are the basis for forensic interpretation of measurements. PCG showed a greater long-term stability after six months in deep frozen serum and urine samples than psilocin. The short-term stability of PCG for one week in whole blood at room temperature and in deep frozen samples was also better than that of psilocin. Therefore, PCG can be considered to be more stable than the labile psilocin and should always be included if psilocin is analyzed in samples.

  7. Dosage delivery of sensitive reagents enables glove-box-free synthesis

    NASA Astrophysics Data System (ADS)

    Sather, Aaron C.; Lee, Hong Geun; Colombe, James R.; Zhang, Anni; Buchwald, Stephen L.

    2015-08-01

    Contemporary organic chemists employ a broad range of catalytic and stoichiometric methods to construct molecules for applications in the material sciences, and as pharmaceuticals, agrochemicals, and sensors. The utility of a synthetic method may be greatly reduced if it relies on a glove box to enable the use of air- and moisture-sensitive reagents or catalysts. Furthermore, many synthetic chemistry laboratories have numerous containers of partially used reagents that have been spoiled by exposure to the ambient atmosphere. This is exceptionally wasteful from both an environmental and a cost perspective. Here we report an encapsulation method for stabilizing and storing air- and moisture-sensitive compounds. We demonstrate this approach in three contexts, by describing single-use capsules that contain all of the reagents (catalysts, ligands, and bases) necessary for the glove-box-free palladium-catalysed carbon-fluorine, carbon-nitrogen, and carbon-carbon bond-forming reactions. This strategy should reduce the number of error-prone, tedious and time-consuming weighing procedures required for such syntheses and should be applicable to a wide range of reagents, catalysts, and substrate combinations.

  8. COSAL: A black-box compressible stability analysis code for transition prediction in three-dimensional boundary layers

    NASA Technical Reports Server (NTRS)

    Malik, M. R.

    1982-01-01

    A fast computer code COSAL for transition prediction in three dimensional boundary layers using compressible stability analysis is described. The compressible stability eigenvalue problem is solved using a finite difference method, and the code is a black box in the sense that no guess of the eigenvalue is required from the user. Several optimization procedures were incorporated into COSAL to calculate integrated growth rates (N factor) for transition correlation for swept and tapered laminar flow control wings using the well known e to the Nth power method. A user's guide to the program is provided.

  9. Total synthesis of the potent microtubule-stabilizing agent (+)-discodermolide.

    PubMed

    Harried, Scott S; Lee, Christopher P; Yang, Ge; Lee, Tony I H; Myles, David C

    2003-08-22

    The total synthesis of the potent microtubule-stabilizing, antimitotic agent (+)-discodermolide is described. The convergent synthetic strategy takes advantage of the diastereoselective alkylation of a ketone enolate to establish the key C15-C16 bond. The synthesis is amenable to preparation of gram-scale quantities of (+)-discodermolide and analogues.

  10. Expanding the amino acid repertoire of ribosomal polypeptide synthesis via the artificial division of codon boxes

    NASA Astrophysics Data System (ADS)

    Iwane, Yoshihiko; Hitomi, Azusa; Murakami, Hiroshi; Katoh, Takayuki; Goto, Yuki; Suga, Hiroaki

    2016-04-01

    In ribosomal polypeptide synthesis the library of amino acid building blocks is limited by the manner in which codons are used. Of the proteinogenic amino acids, 18 are coded for by multiple codons and therefore many of the 61 sense codons can be considered redundant. Here we report a method to reduce the redundancy of codons by artificially dividing codon boxes to create vacant codons that can then be reassigned to non-proteinogenic amino acids and thereby expand the library of genetically encoded amino acids. To achieve this, we reconstituted a cell-free translation system with 32 in vitro transcripts of transfer RNASNN (tRNASNN) (S = G or C), assigning the initiator and 20 elongator amino acids. Reassignment of three redundant codons was achieved by replacing redundant tRNASNNs with tRNASNNs pre-charged with non-proteinogenic amino acids. As a demonstration, we expressed a 32-mer linear peptide that consists of 20 proteinogenic and three non-proteinogenic amino acids, and a 14-mer macrocyclic peptide that contains more than four non-proteinogenic amino acids.

  11. T-box3 is a ciliary protein and regulates stability of the Gli3 transcription factor to control digit number

    PubMed Central

    Emechebe, Uchenna; Kumar P, Pavan; Rozenberg, Julian M; Moore, Bryn; Firment, Ashley; Mirshahi, Tooraj; Moon, Anne M

    2016-01-01

    Crucial roles for T-box3 in development are evident by severe limb malformations and other birth defects caused by T-box3 mutations in humans. Mechanisms whereby T-box3 regulates limb development are poorly understood. We discovered requirements for T-box at multiple stages of mouse limb development and distinct molecular functions in different tissue compartments. Early loss of T-box3 disrupts limb initiation, causing limb defects that phenocopy Sonic Hedgehog (Shh) mutants. Later ablation of T-box3 in posterior limb mesenchyme causes digit loss. In contrast, loss of anterior T-box3 results in preaxial polydactyly, as seen with dysfunction of primary cilia or Gli3-repressor. Remarkably, T-box3 is present in primary cilia where it colocalizes with Gli3. T-box3 interacts with Kif7 and is required for normal stoichiometry and function of a Kif7/Sufu complex that regulates Gli3 stability and processing. Thus, T-box3 controls digit number upstream of Shh-dependent (posterior mesenchyme) and Shh-independent, cilium-based (anterior mesenchyme) Hedgehog pathway function. DOI: http://dx.doi.org/10.7554/eLife.07897.001 PMID:27046536

  12. T-box3 is a ciliary protein and regulates stability of the Gli3 transcription factor to control digit number.

    PubMed

    Emechebe, Uchenna; Kumar P, Pavan; Rozenberg, Julian M; Moore, Bryn; Firment, Ashley; Mirshahi, Tooraj; Moon, Anne M

    2016-01-01

    Crucial roles for T-box3 in development are evident by severe limb malformations and other birth defects caused by T-box3 mutations in humans. Mechanisms whereby T-box3 regulates limb development are poorly understood. We discovered requirements for T-box at multiple stages of mouse limb development and distinct molecular functions in different tissue compartments. Early loss of T-box3 disrupts limb initiation, causing limb defects that phenocopy Sonic Hedgehog (Shh) mutants. Later ablation of T-box3 in posterior limb mesenchyme causes digit loss. In contrast, loss of anterior T-box3 results in preaxial polydactyly, as seen with dysfunction of primary cilia or Gli3-repressor. Remarkably, T-box3 is present in primary cilia where it colocalizes with Gli3. T-box3 interacts with Kif7 and is required for normal stoichiometry and function of a Kif7/Sufu complex that regulates Gli3 stability and processing. Thus, T-box3 controls digit number upstream of Shh-dependent (posterior mesenchyme) and Shh-independent, cilium-based (anterior mesenchyme) Hedgehog pathway function. PMID:27046536

  13. The Laser Synthesis of Linear Polyynes: The Particle in a Box Revisited

    ERIC Educational Resources Information Center

    Anderson, Bruce D.; Gordon, Christopher M.

    2008-01-01

    In this experiment, linear polyynes are synthesized and then the predictions of a one-dimensional, particle in a box are used to calculate the quantum mechanical box length for the polyynes. A solution of graphite in ethanol is irradiated with a Nd:YAG laser (532 nm) and the resulting solution is filtered and analyzed. Data from gas…

  14. The stability of the compression cover of box beams stiffened by posts

    NASA Technical Reports Server (NTRS)

    Seide, Paul; Barrett, Paul F

    1951-01-01

    An investigation is made of the buckling of the compression cover of post-stiffened box beams subjected to end moments. Charts are presented for the determination of the minimum post axial stiffnesses and the corresponding compressive buckling loads required for the compression cover to buckle with nodes through the posts. Application of the charts to design and analysis and the limitations of their use are discussed.

  15. Synthesis of metallic nanoshells on porphyrin-stabilized emulsions

    DOEpatents

    Wang, Haorong; Song, Yujiang; Shelnutt, John A.; Medforth, Craig J.

    2011-12-13

    Metal nanostructures formed by photocatalytic interfacial synthesis using a porphyrin-stabilized emulsion template and the method for making the nanostructures. Catalyst-seeded emulsion droplets are employed as templates for hollow-nanoshell growth. The hollow metal nanospheres may be formed with or without inclusions of other materials.

  16. Control augmented structural synthesis with dynamic stability constraints

    NASA Technical Reports Server (NTRS)

    Thomas, H. L.; Schmit, L. A., Jr.

    1989-01-01

    Dynamic stability constraints are included in a computer program that simultaneously synthesizes a structure and its control system. Two measures of stability, the real part of the system complex eigenvalues and the damping ratio, are examined. The procedure for calculating the sensitivities of the two measures of stability to changes in the structure and its control system is explained. The sensitivities are used to formulate an approximate problem that is solved at each design iteration. The effects of structural damping and noncollated controllers on the synthesis process are discussed.

  17. 1-Alkenylcalcium iodide: synthesis and stability.

    PubMed

    Köhler, Mathias; Görls, Helmar; Langer, Jens; Westerhausen, Matthias

    2014-04-25

    To enhance the scope of heavy calcium-based Grignard reagents, 1,2-dihydro-4-iodonaphthalene (1) was reduced with calcium in THF giving tetrakis(thf) (1,2-dihydronaphth-4-yl)calcium iodide (2). This derivative represents a 1-alkenylcalcium complex based on X-ray structure determination and NMR data. The stability of this compound is significantly reduced compared with the aromatic naphthylcalcium iodide. PMID:24677436

  18. Interfacial synthesis and functionality of self-stabilized polydiaminonaphthalene nanoparticles.

    PubMed

    Li, Xin-Gui; Zhang, Jia-Li; Huang, Mei-Rong

    2012-08-01

    A simple and effective template-free synthesis method for nanosized conducting polymers with self-stability and functionality is a main challenge. Herein, a strategy is reported for the facile synthesis of poly(1,5-diaminonaphthalene) nanospherical particles by an interfacial miniemulsion oxidative polymerization of 1,5-diaminonaphthalene at mobile microinterfaces between a stirred biphase without external emulsifiers. The size of the nanospheres was carefully optimized by controlling the polymerization conditions. Formation and self-stabilization mechanisms of the nanoparticles are proposed. The constantly movable and refreshed microinterface is a key to successful synthesis of the nanospheres, for significantly suppressing secondary growth leading to agglomerated particles because vigorous stirring makes as-formed self-stabilized nanospheres instantly leave the microinterfaces. The resulting nanospheres possess several advantages: clean surface, self-stability, redispersibility, semiconductivity, electroactivity, and fluorescence emission. The fluorescence emission can be quenched by specific quenchers, thus enabling low-cost, high-performance chemosensors to be obtained for the sensitive detection of Zn(II) ions in a wide linear concentration range of more than five orders of magnitude with a superior detection limit down to 1 nM.

  19. Theoretical insight into the structural stability of KZnB3O6 polymorphs with different BO(x) polyhedral networks.

    PubMed

    Yang, Lei; Fan, Weiliu; Li, Yanlu; Sun, Honggang; Wei, Lei; Cheng, Xiufeng; Zhao, Xian

    2012-06-18

    In general, the presence of shared edges of polyhedra for high-valence low-coordinated small cations is rarely seen except under extreme conditions such as high pressure. However, the ambient-pressure synthesis of KZnB(3)O(6) built of edge-sharing BO(4) tetrahedra is contrary to this. By investigating the molecular dynamics, lattice dynamics, and electronic properties via density functional theory, we studied the origin of the phase stability of the edge-sharing (es) and "corner-sharing (cs)" KZnB(3)O(6). Lattice dynamics results show that there are no phonon anomalies that could lead to the instability of es-KZnB(3)O(6), which is consistent with molecular dynamics analysis. For "cs-KZnB(3)O(6)", a soft mode at the G point in the phonon dispersion is identified that reflects the dynamic instability with respect to small distortions. Eigenvector analysis of the soft mode of "cs-KZnB(3)O(6)" indicates that the instability comes from the linkage of ZnO(5) polyhedra rather than BO(x) polyhedra. Electronic property calculation indicates that the edge-sharing BO(4) polyhedra connected by the longest B-O σ bonds provide a solid framework for es-KZnB(3)O(6). In the case of "cs-KZnB(3)O(6)", the overlong Zn-O bond possesses the smallest covalent nature and the least orbital overlap among the bonds in a ZnO(5) polyhedron, and these two features of the electronic structure reduce the stability of "cs-KZnB(3)O(6)" compared to es-KZnB(3)O(6). The electronic property calculation further confirms the results obtained from lattice dynamics analysis. PMID:22667686

  20. Box-Behnken Design of Experiments Investigation of Hydroxyapatite Synthesis for Orthopedic Applications

    NASA Astrophysics Data System (ADS)

    Kehoe, S.; Stokes, J.

    2011-03-01

    Physicochemical properties of hydroxyapatite (HAp) synthesized by the chemical precipitation method are heavily dependent on the chosen process parameters. A Box-Behnken three-level experimental design was therefore, chosen to determine the optimum set of process parameters and their effect on various HAp characteristics. These effects were quantified using design of experiments (DoE) to develop mathematical models using the Box-Behnken design, in terms of the chemical precipitation process parameters. Findings from this research show that the HAp possessing optimum powder characteristics for orthopedic application via a thermal spray technique can therefore be prepared using the following chemical precipitation process parameters: reaction temperature 60 °C, ripening time 48 h, and stirring speed 1500 rpm using high reagent concentrations. Ripening time and stirring speed significantly affected the final phase purity for the experimental conditions of the Box-Behnken design. An increase in both the ripening time (36-48 h) and stirring speed (1200-1500 rpm) was found to result in an increase of phase purity from 47(±2)% to 85(±2)%. Crystallinity, crystallite size, lattice parameters, and mean particle size were also optimized within the research to find desired settings to achieve results suitable for FDA regulations.

  1. Jeweled Boxes

    ERIC Educational Resources Information Center

    Coy, Mary

    2009-01-01

    While an empty cardboard box from a ream of copy paper may be the most coveted box among teachers in the author's school, for other people, brass boxes from India, Khokhlova lacquer boxes from Russia, and puzzle boxes from Japan are more the type that are collected and admired. Whether it is used for storage or decoration, a box can evoke a sense…

  2. Carbohydrate protease conjugates: Stabilized proteases for peptide synthesis

    SciTech Connect

    Wartchow, C.A.; Wang, Peng; Bednarski, M.D.; Callstrom, M.R. |

    1995-12-31

    The synthesis of oligopeptides using stable carbohydrate protease conjugates (CPCs) was examined in acetonitrile solvent systems. CPC[{alpha}-chymotrypsin] was used for the preparation of peptides containing histidine, phenylalanine, tryptophan in the P{sub 1} position in 60-93% yield. The CPC[{alpha}-chymotrypsin]-catalyzed synthesis of octamer Z-Gly-Gly-Phe-Gly-Gly-Phe-Gly-Gly-OEt from Z-Gly-Gly-Phe-Gly-Gly-Phe-OMe was achieved in 71% yield demonstrating that synthesis peptides containing both hydrophylic and hydrophobic amino acids. The P{sub 2} specificity of papain for aromatic residues was utilized for the 2 + 3 coupling of Z-Tyr-Gly-OMe to H{sub 2}N-Gly-Phe-Leu-OH to generate the leucine enkephalin derivative in 79% yield. Although papain is nonspecific for the hydrolysis of N-benzyloxycarbonyl amino acid methyl esters in aqueous solution, the rates of synthesis for these derivitives with nucleophile leucine tert-butyl ester differed by nearly 2 orders of magnitude. CPC[thermolysin] was used to prepare the aspartame precursor Z-Asp-Phe-OMe in 90% yield. The increased stability of CPCs prepared from periodate-modified poly(2-methacryl- amido-2-deoxy-D-glucose), poly(2-methacrylamido-2-deoxy-D-galactose), and poly(5-methacryl-amido-5-deoxy-D-ribose), carbohydrate materials designed to increase the aldehyde concentration in aqueous solution, suggests that the stability of CPCs is directly related to the aldehyde concentration of the carbohydrate material. Periodate oxidation of poly(2-methacrylamido-2-deoxy-D-glucose) followed by covalent attachment to {alpha}-chymotrypsin gave a CPC with catalytic activity in potassium phosphate buffer at 90{degrees}C for 2 h. 1 fig., 1 tab., 40 refs.

  3. Second-site long terminal repeat (LTR) revertants of replication-defective human immunodeficiency virus: effects of revertant TATA box motifs on virus infectivity, LTR-directed expression, in vitro RNA synthesis, and binding of basal transcription factors TFIID and TFIIA.

    PubMed Central

    Kashanchi, F; Shibata, R; Ross, E K; Brady, J N; Martin, M A

    1994-01-01

    Second-site revertants from replication-incompetent molecular clones of human immunodeficiency virus (HIV) contain base substitutions adjacent to the TATA motif. The altered TATA box motifs were analyzed for their effect(s) on virus infectivity, long terminal repeat (LTR)-directed expression in transient transfection assays, in vitro RNA synthesis, and assembly of the TFIID-TFIIA preinitiation complex. The revertant TATA boxes accelerated the kinetics of HIV replication when present in the context of an LTR containing a Sp1 mutation (deletion or site specific); no effect was observed on the infectivity of wild-type HIV. In chloramphenicol acetyltransferase assays and in vitro transcription systems, the altered TATA box motifs led to elevated basal levels of RNA synthesis from NF-kappa B- and Sp1-mutagenized and wild-type templates, respectively, but did not increase responsiveness to Tat transactivation. The revertant TATA boxes accelerated the binding of TFIID and TFIIA to the LTR and stabilized their association with the promoter. The revertants did not assemble a more-processive elongation complex. These results suggest that in the context of an impaired enhancer/promoter (viz., three mutated Sp1 elements), a series of HIV revertants emerge which contain LTR alterations that significantly augment basal RNA synthesis. The TATA motif revertants are capable of rescuing the enhancer/promoter defect and sustain virus infectivity. Images PMID:8151790

  4. Inhibition of Protein Synthesis by Y Box-Binding Protein 1 Blocks Oncogenic Cell Transformation†

    PubMed Central

    Bader, Andreas G.; Vogt, Peter K.

    2005-01-01

    The multifunctional Y box-binding protein 1 (YB-1) is transcriptionally repressed by the oncogenic phosphoinositide 3-kinase (PI3K) pathway (with P3K as an oncogenic homolog of the catalytic subunit) and, when reexpressed with the retroviral vector RCAS, interferes with P3K- and Akt-induced transformation of chicken embryo fibroblasts. Retrovirally expressed YB-1 binds to the cap of mRNAs and inhibits cap-dependent and cap-independent translation. To determine the requirements for the inhibitory role of YB-1 in P3K-induced transformation, we conducted a mutational analysis, measuring YB-1-induced interference with transformation, subcellular localization, cap binding, mRNA binding, homodimerization, and inhibition of translation. The results show that (i) interference with transformation requires RNA binding and a C-terminal domain that is distinct from the cytoplasmic retention domain, (ii) interference with transformation is tightly correlated with inhibition of translation, and (iii) masking of mRNAs by YB-1 is not sufficient to block transformation or to inhibit translation. We identified a noncanonical nuclear localization signal (NLS) in the C-terminal half of YB-1. A mutant lacking the NLS retains its ability to interfere with transformation, indicating that a nuclear function is not required. These results suggest that YB-1 interferes with P3K-induced transformation by a specific inhibition of translation through its RNA-binding domain and a region in the C-terminal domain. Potential functions of the C-terminal region are discussed. PMID:15743808

  5. One-step synthesis of lignosulfonate-stabilized silver nanoparticles.

    PubMed

    Milczarek, Grzegorz; Rebis, Tomasz; Fabianska, Justyna

    2013-05-01

    Softwood lignosulfonate (SLS) was used as a reducing agent for one-step synthesis of silver nanoparticles (SLS-AgNPs) in an aqueous solution at room temperature. In this reaction SLS acts also as a stabilizing agent and as a result, stable colloids of silver nanoparticles are formed during the reaction with the average particle size of 41 nm. The obtained SLS-AgNPs were characterized by UV-vis spectrophotometry, size distribution and AFM imaging after casting on mica. Due to metal ion complexing capability of lignosulfonates, the SLS-AgNPs appeared to be capable of colorimetric detection of metal ions (especially nickel). Additionally, the SLS-AgNPs could be assembled into thin films on conducting substrates (ITO glass) using electrophoretic deposition. XPS spectroscopy was used to characterize such films and revealed a strong interaction of silver atoms with some carbon atoms of the SLS.

  6. New stabilized FastPrep-CLEAs for sialic acid synthesis.

    PubMed

    García-García, María Inmaculada; Sola-Carvajal, Agustín; Sánchez-Carrón, Guiomar; García-Carmona, Francisco; Sánchez-Ferrer, Alvaro

    2011-05-01

    N-acetyl-D-neuraminic acid aldolase, a key enzyme in the biotechnological production of N-acetyl-D-neuraminic acid (sialic acid) from N-acetyl-D-mannosamine and pyruvate, was immobilized as cross-linked enzyme aggregates (CLEAs) by precipitation with 90% ammonium sulfate and crosslinking with 1% glutaraldehyde. Because dispersion in a reciprocating disruptor (FastPrep) was only able to recover 40% of the activity, improved CLEAs were then prepared by co-aggregation of the enzyme with 10mg/mL bovine serum albumin followed by a sodium borohydride treatment and final disruption by FastPrep (FastPrep-CLEAs). This produced a twofold increase in activity up to 86%, which is a 30% more than that reported for this aldolase in cross-linked inclusion bodies (CLIBs). In addition, these FastPrep-CLEAs presented remarkable biotechnological features for Neu5Ac synthesis, including, good activity and stability at alkaline pHs, a high K(M) for ManNAc (lower for pyruvate) and good operational stability. These results reinforce the practicability of using FastPrep-CLEAs in biocatalysis, thus reducing production costs and favoring reusability.

  7. Si-substituted hydroxyapatite nanopowders: Synthesis, thermal stability and sinterability

    SciTech Connect

    Bianco, Alessandra Cacciotti, Ilaria; Lombardi, Mariangela Montanaro, Laura

    2009-02-04

    Synthetic hydroxyapatites incorporating small amounts of Si have shown improved biological performances in terms of enhanced bone apposition, bone in-growth and cell-mediated degradation. This paper reports a systematic investigation on Si-substituted hydroxyapatite (Si 1.40 wt%) nanopowders produced following two different conventional wet methodologies: (a) precipitation of Ca(NO{sub 3}){sub 2}.4H{sub 2}O and (b) titration of Ca(OH){sub 2}. The influence of the synthesis process on composition, thermal behaviour and sinterability of the resulting nanopowders is studied. Samples were characterised by electron microscopy, induced coupled plasma atomic emission spectroscopy, thermal analysis, infrared spectroscopy, N{sub 2} adsorption measurements, X-ray diffraction and dilatometry. Semicrystalline Si-substituted hydroxyapatite powders made up of needle-like nanoparticles were obtained, the specific surface area ranged between 84 and 110 m{sup 2}/g. Pure and Si-substituted hydroxyapatite nanopowders derived from Ca(NO{sub 3}){sub 2}.4H{sub 2}O decomposed around 1000 deg. C. Si-substituted hydroxyapatite nanopowders obtained from Ca(OH){sub 2} were thermally stable up to 1200 deg. C and showed a distinct decreased thermal stability with respect to the homologous pure sample. Si-substituted hydroxyapatites exhibited higher sintering temperature and increased total shrinkage with respect to pure powders. Nanostructured dense ceramics were obtained by sintering at 1100 deg. C Si-substituted hydroxyapatites derived from Ca(OH){sub 2}.

  8. Synthesis, Structure, Stability and Redispersion of Gold-based Nanoparticles

    NASA Astrophysics Data System (ADS)

    Tiruvalam, Ram Chandra

    Nanoscale gold has been shown to possess an intriguing combination of unexpected optical, photochemical and catalytic properties. The ability to control the size, shape, morphology, composition and dispersion of gold-based nanostructures is key to optimizing their performance for nanotechnology applications. The advanced electron microscopy studies described in this thesis analyze three important aspects of gold and gold-palladium alloy nanoparticles: namely, (i) the ability to synthesize gold nanoparticles of controlled size and shape in an aqueous medium; (ii) the colloidal preparation of designer gold-palladium alloys for selective oxidation catalysis; and (iii) the ability to disperse gold as finely and homogeneously as possible on a metal oxide or carbon support. The ability to exploit the nanoscale properties of gold for various engineering applications often depends on our ability to control size and shape of the nanoscale entity by careful manipulation of the synthesis parameters. We have explored an aqueous based synthesis route, using oleylamine as both a reductant and surfactant, for preparing gold nanostructures. By systematically varying synthesis parameters such as oleylamine concentration, reaction temperature, and aging time it is possible to identify processing regimens that generate Au nanostructures having either pseudo-spherical, faceted polyhedral, nanostar or wire shaped morphologies. Furthermore, by quenching the reaction partway through it is possible to create a class of metastable Au-containing structures such as nanocubes, nanoboxes and nanowires. Possible formation mechanisms for these gold based nano-objects are discussed. There is a growing interest in using supported bimetallic AuPd alloy nanoparticles for selective oxidation reactions. In this study, a systematic series of size controlled AuPd bimetallic particles have been prepared by colloidal synthesis methods. Particles having random alloy structures, as well as `designer

  9. Stability of plant immune-receptor resistance proteins is controlled by SKP1-CULLIN1-F-box (SCF)-mediated protein degradation

    PubMed Central

    Cheng, Yu Ti; Li, Yingzhong; Huang, Shuai; Huang, Yan; Dong, Xinnian; Zhang, Yuelin; Li, Xin

    2011-01-01

    The nucleotide-binding domain and leucine-rich repeats containing proteins (NLRs) serve as immune receptors in both plants and animals. Overaccumulation of NLRs often leads to autoimmune responses, suggesting that the levels of these immune receptors must be tightly controlled. However, the mechanism by which NLR protein levels are regulated is unknown. Here we report that the F-box protein CPR1 controls the stability of plant NLR resistance proteins. Loss-of-function mutations in CPR1 lead to higher accumulation of the NLR proteins SNC1 and RPS2, as well as autoactivation of immune responses. The autoimmune responses in cpr1 mutant plants can be largely suppressed by knocking out SNC1. Furthermore, CPR1 interacts with SNC1 and RPS2 in vivo, and overexpressing CPR1 results in reduced accumulation of SNC1 and RPS2, as well as suppression of immunity mediated by these two NLR proteins. Our data suggest that SKP1-CULLIN1-F-box (SCF) complex-mediated stability control of plant NLR proteins plays an important role in regulating their protein levels and preventing autoimmunity. PMID:21873230

  10. Immobilization-stabilization of proteases as a tool to improve the industrial design of peptide synthesis.

    PubMed

    Blanco, R M; Bastida, A; Cuesta, C; Alvaro, G; Fernandez-Lafuente, R; Rosell, C M; Guisan, J M

    1991-01-01

    Synthesis of dipeptides benzoyl Arginine leucinamide and kyotorphin catalyzed by highly stabilized derivatives of trypsin and chymotrypsin have been performed. Extreme experimental conditions could be tested and parameters of industrial interest could be improved provided the high activity and stability of the derivatives in these unfavourable environments. Thermodynamically controlled synthesis catalyzed by trypsin could be optimized and 97% conversion was obtained in 90% organic cosolvents. 100% yields were achieved in kinetically controlled synthesis catalyzed by trypsin in aqueous medium in the presence of IM Ammonium Sulphate. Higher starting concentrations of poorly soluble substrates of chymotrypsin could be used in a reaction medium containing 50% DMF and 95% yield were obtained.

  11. Bento Boxes

    ERIC Educational Resources Information Center

    Hasio, Cindy

    2010-01-01

    Bento boxes are common objects in Japanese culture, designed to hold enough lunch for one person. They have individual compartments and sometimes multiple tiers for rice, vegetables, and other side dishes. They are made of materials ranging from wood, cloth, aluminum, or plastic. In general, the greater the number of foods, the better the box is…

  12. Boxed In!

    ERIC Educational Resources Information Center

    Stevens, Judith

    2007-01-01

    Early years practitioners know what parents are reminded of every Christmas Day--it does not matter how long families spend carefully selecting the presents, the children are likely to spend longer playing with the empty boxes! Children are fascinated with boxes and practitioners can capitalise on this and support early mathematical development…

  13. Film Boxes.

    ERIC Educational Resources Information Center

    Osterer, Irv

    2002-01-01

    Presents an art lesson in which students created three-dimensional designs for 35mm film packages to improve graphic arts learning. Describes how the students examined and created film boxes using QuarkXPress software. (CMK)

  14. Synthesis and Characterization of Processable Polyimides with Enhanced Thermal Stability

    NASA Technical Reports Server (NTRS)

    Harris, Frank W.

    1999-01-01

    The following is a summary report of the research carried out under NASA Grant NAG-1-448. The work was divided into four major areas: 1) Enhanced polyimide processing through the use of reactive plasticizers 2) Development of processable polyhenylquinoxalines 3) Synthesis and characterization of perfluorovinylether-terminated imide oligomers and 4) Fluorosilicones containing perfuorocyclobutane rings.

  15. Design, Synthesis, and Characterization of Cyclic Peptidomimetics of the Inducible Nitric Oxide Synthase Binding Epitope That Disrupt the Protein-Protein Interaction Involving SPRY Domain-Containing Suppressor of Cytokine Signaling Box Protein (SPSB) 2 and Inducible Nitric Oxide Synthase.

    PubMed

    Harjani, Jitendra R; Yap, Beow Keat; Leung, Eleanor W W; Lucke, Andrew; Nicholson, Sandra E; Scanlon, Martin J; Chalmers, David K; Thompson, Philip E; Norton, Raymond S; Baell, Jonathan B

    2016-06-23

    SPRY domain-containing suppressor of cytokine signaling box protein (SPSB) 2-deficient macrophages have been found to exhibit prolonged expression of inducible nitric oxide synthase (iNOS) and enhanced killing of persistent pathogens, suggesting that inhibitors of the SPSB2-iNOS interaction have potential as novel anti-infectives. In this study, we describe the design, synthesis, and characterization of cyclic peptidomimetic inhibitors of the SPSB2-iNOS interaction constrained by organic linkers to improve stability and druggability. SPR, ITC, and (19)F NMR analyses revealed that the most potent cyclic peptidomimetic bound to the iNOS binding site of SPSB2 with low nanomolar affinity (KD 29 nM), a 10-fold improvement over that of the linear peptide DINNN (KD 318 nM), and showed strong inhibition of SPSB2-iNOS interaction in macrophage cell lysates. This study exemplifies a novel approach to cyclize a Type II β-turn linear peptide and provides a foundation for future development of this group of inhibitors as new anti-infectives.

  16. Generic Biocombinatorial Strategy to Select Tailor-Made Stabilizers for Sol-Gel Nanoparticle Synthesis.

    PubMed

    Hanßke, Felix; Kemnitz, Erhard; Börner, Hans G

    2015-09-01

    A generic route for the selection of nanoparticle stabilizers via biocombinatorial means of phage display peptide screening is presented, providing magnesium fluoride nanoparticle synthesis as example. Selected sequence-specific MgF2 binders are evaluated for their adsorption behavior. Peptide-polymer conjugates derived from the best binding peptide are used for the stabilization of MgF2 sol nanoparticles, yielding fully redispersable dry states and improoving processability significantly.

  17. High-temperature stabilization by air of a pyrophoric catalyst for the synthesis of ammonia

    SciTech Connect

    Krylova, A.V.; Ustimenko, G.A.

    1982-12-01

    The reaction of a catalyst for the synthesis of ammonia with air at 480 to 520/sup 0/C leads to the formation on the surface of a thin protective oxide structure that eliminates its pyrophoric character. High-temperature stabilization by air is a considerably faster process than passivation and leads to the production of catalysts with increased resistance to oxidation.

  18. Cy-SaBOX/Copper(II)-Catalyzed Highly Diastereo- and Enantioselective Synthesis of Bicyclic N,O Acetals.

    PubMed

    Liu, Qiong-Jie; Wang, Lijia; Kang, Qi-Kai; Zhang, X Peter; Tang, Yong

    2016-08-01

    Facile and effective access for the asymmetric construction of the useful and important skeleton of the bicyclic N,O-acetals is described. Cu(II) /SaBOX could catalyze the reaction of β,γ-unsaturated α-ketoesters with cyclic enamines efficiently, thus affording the desired products in excellent yields with excellent stereoselectivities (21 examples; up to 99 % yields; up to >95:5 d.r.; and 95-99 % ee). This reaction can be well performed on gram scale, even with only 1 mol % catalyst loading. The single-crystal structures of the copper complexes lead to a good understanding of the stereo-synergistic effects of the sidearm. PMID:27351738

  19. Exploding Boxes

    ERIC Educational Resources Information Center

    Kinney; Jan

    2011-01-01

    How do you teach the "same old, same old" in an interesting and inexpensive way? Art teachers are forever looking for new angles on the good-old elements and principles. And, as budgets tighten, they are trying to be as frugal as possible while still holding their students' attention. Enter exploding boxes! In conceptualizing the three types of…

  20. Electron beam assisted synthesis of silver nanoparticle in chitosan stabilizer: Preparation, stability and inhibition of building fungi studies

    NASA Astrophysics Data System (ADS)

    Jannoo, Kanokwan; Teerapatsakul, Churapa; Punyanut, Adisak; Pasanphan, Wanvimol

    2015-07-01

    Silver nanoparticles (AgNPs) in chitosan (CS) stabilizer were successfully synthesized using electron beam irradiation. The effects of irradiation dose, molecular weight (MW) of CS stabilizer, concentration of AgNO3 precursor and addition of tert-butanol on AgNPs production were studied. The stability of the AgNPs under different temperatures and storage times were also investigated. The AgNPs formation in CS was observed using UV-vis, FT-IR and XRD. The characteristic surface plasmon resonance (SPR) of the obtained AgNPs was around 418 nm. The CS stabilizer and its MW, AgNO3 precursor and irradiation doses are important parameters for the synthesis of AgNPs. The optimum addition of 20% v/v tert-butanol could assist the formation of AgNPs. The AgNPs in CS stabilizer were stable over a period of one year when the samples were kept at 5 °C. The AgNPs observed from TEM images were spherical with an average particle size in the range of 5-20 nm depending on the irradiation doses. The AgNPs in CS solution effectively inhibited the growth of several fungi, i.e., Curvularia lunata, Trichoderma sp., Penicillium sp. and Aspergillus niger, which commonly found on the building surface.

  1. Synthesis of a combined system for precise stabilization of the Spektr-UF observatory: II

    NASA Astrophysics Data System (ADS)

    Bychkov, I. V.; Voronov, V. A.; Druzhinin, E. I.; Kozlov, R. I.; Ul'yanov, S. A.; Belyaev, B. B.; Telepnev, P. P.; Ul'yashin, A. I.

    2014-03-01

    The paper presents the second part of the results of search studies for the development of a combined system of high-precision stabilization of the optical telescope for the designed Spectr-UF international observatory [1]. A new modification of the strict method of the synthesis of nonlinear discrete-continuous stabilization systems with uncertainties is described, which is based on the minimization of the guaranteed accuracy estimate calculated using vector Lyapunov functions. Using this method, the synthesis of the feedback parameters in the mode of precise inertial stabilization of the optical telescope axis is performed taking the design nonrigidity, quantization of signals over time and level, and errors of orientation meters, as well as the errors and limitation of control moments of executive engine-flywheels into account. The results of numerical experiments that demonstrate the quality of the synthesized system are presented.

  2. Synthesis and thermal stability of carborane containing phosphazenes

    NASA Technical Reports Server (NTRS)

    Fewell, L. L.; Basi, R. J.; Parker, J. A.

    1983-01-01

    Carborane substituted polyphosphazenes were prepared by the thermal polymerization of phenyl-carboranyl penta chlorocyclotriphosphazene. Successive isothermal vacuum pyrolyses were conducted on the polymer and examined for structural changes by infrared spectroscopy. The degradation products were ascertained by gas chromatography-mass spectrometric analysis. It was found that the presence of the carborane group improves the thermal stability of the polymer by retarding the ring chain equilibrium processes of decomposition.

  3. Synthesis of Co2+ and Ni2+ stabilized beta alumina

    SciTech Connect

    Chen, S.; White, D.R.; Sato, H.; Sandberg, C.J.; Harrison, H.R.

    1983-10-01

    By using a skull melting technique, both single crystalline Ni(2+) and Co(2+) stabilized beta double prime-aluminas and doped beta-aluminas have been synthesized. Both Ni(2+) and Co(2+) beta-aluminas are blue in color, although the Co(2+) material has a deeper hue. Analysis of their visible absorption spectra indicated that the divalent transition metal ions are situated in tetrahedral sites of the spinel blocks.

  4. Photobleaching and stabilization of carbon nanodots produced by solvothermal synthesis.

    PubMed

    Wang, Wenshuo; Damm, Cornelia; Walter, Johannes; Nacken, Thomas J; Peukert, Wolfgang

    2016-01-01

    In this work we performed a detailed investigation of the photostability of bottom-up produced carbon nanodots (CDs) prepared from citric acid and urea by solvothermal synthesis. Analytical ultracentrifugation (AUC) reveals that the CDs have a hydrodynamic diameter of <1 nm and a very narrow size distribution. In the community it is widely assumed that CDs are photo-stable. In contrast, we found that CDs exposed to UV-irradiation exhibit noteworthy fluorescence degeneration compared to freshly prepared CDs or CDs stored in the dark, indicating that fluorescence bleaching is caused by a photochemical process. We found that fluorescence intensity decay due to exposure to UV-irradiation is accelerated in the presence of oxygen and identified the surface status of CDs as the decisive factor of fluorescence bleaching of CDs. Based on a discussion on the underlying mechanisms we show how to avoid photobleaching of CDs. PMID:26616577

  5. Synthesis and Structural Stability of Ti2GeC

    SciTech Connect

    Phatak, N.; Saxena, S; Fei, Y; Hu, J

    2009-01-01

    In this paper we report the synthesis of a ternary-layered ceramic, Ti2GeC, a 211 Mn+1AXn compound by hot-pressing. X-ray analysis confirmed the hexagonal crystal symmetry. Using a synchrotron radiation and a diamond anvil cell, we measured the pressure dependencies of the lattice parameters. The phase is structurally stable up to the 49 GPa-the maximum experimental pressure reached. The bulk modulus of Ti2GeC calculated using the Birch-Murnaghan equation of state is 211 {+-} 4 GPa with K? = 3.9 {+-} 0.2. Surprisingly the bulk modulus was found to be greater than both Ti2AlC and Ti2SC by 13% and 10%. Also, Ti2GeC has the highest bulk modulus among M2GeC phases where M = Ti, V, Cr.

  6. Synthesis, optical properties, stability, and encapsulation of Cu-nanoparticles

    NASA Astrophysics Data System (ADS)

    Bashir, Ommer; Hussain, Shokit; AL-Thabaiti, Shaeel Ahmed; Khan, Zaheer

    2015-04-01

    Starch-capped copper nanoparticles (CuNPs) were prepared by a chemical reduction method using hydrazine, copper sulfate and starch as reducing, oxidizing and stabilizing agents, respectively, for the first time at room temperature. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction patterns (EDX), X-ray photoelectron spectroscopy (XPS), fourier transform infrared (FT-IR) spectroscopy, thermo-gravimetric analysis (TGA), and ultraviolet-visible spectroscopy. The effect of [starch], [hydrazine] and [copper sulfate] on the optical properties of CuNPs were studied by UV-visible spectrophotometrically. The hydrazine concentrations have large impact on the surface Plasmon resonance absorbance, nature of the reaction time curves and reaction rates decreases with [hydrazine]. Starch concentrations have no effect on the path of the CuNPs formation. The hexahedral with some irregular shaped CuNPs were formed in presence of starch with diameter 900 nm. Starch acted as a stabilizing, shape-directing and capping agent during the growth processes. The KI-I2 reagent could not replace CuNps from the inner helical structure of starch.

  7. Synthesis, optical properties, stability, and encapsulation of Cu-nanoparticles.

    PubMed

    Bashir, Ommer; Hussain, Shokit; AL-Thabaiti, Shaeel Ahmed; Khan, Zaheer

    2015-04-01

    Starch-capped copper nanoparticles (CuNPs) were prepared by a chemical reduction method using hydrazine, copper sulfate and starch as reducing, oxidizing and stabilizing agents, respectively, for the first time at room temperature. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction patterns (EDX), X-ray photoelectron spectroscopy (XPS), fourier transform infrared (FT-IR) spectroscopy, thermo-gravimetric analysis (TGA), and ultraviolet-visible spectroscopy. The effect of [starch], [hydrazine] and [copper sulfate] on the optical properties of CuNPs were studied by UV-visible spectrophotometrically. The hydrazine concentrations have large impact on the surface Plasmon resonance absorbance, nature of the reaction time curves and reaction rates decreases with [hydrazine]. Starch concentrations have no effect on the path of the CuNPs formation. The hexahedral with some irregular shaped CuNPs were formed in presence of starch with diameter 900 nm. Starch acted as a stabilizing, shape-directing and capping agent during the growth processes. The KI-I2 reagent could not replace CuNps from the inner helical structure of starch. PMID:25615680

  8. Steric stabilization of Pickering emulsions for the efficient synthesis of polymeric microcapsules.

    PubMed

    Salari, Joris W O; van Heck, Jeroen; Klumperman, Bert

    2010-09-21

    It is commonly known that Pickering emulsions are extremely stable against coalescence and are, therefore, potentially interesting for the synthesis of new materials, such as colloidosomes, microcapsules, composite particles, foams, and so on. However, for the efficient synthesis of such materials, one also has to consider the colloidal stability against aggregation, which is often neglected. In this study, it is demonstrated that steric stabilization is provided to Pickering emulsion droplets by the adsorption of poly(styrene-block-ethylene-co-propylene) (pS-b-EP) and that it is a requirement for the efficient synthesis of polymeric microcapsules. Monodisperse polystyrene particles of 648 nm are synthesized by soap-free emulsion polymerization. A model Pickering emulsion is then formed by the addition of sodium chloride at a critical concentration of 325 mM and mixing it with either heptane or decane. Subsequently, pS-b-EP is added to the Pickering emulsion to provide steric stabilization. Size exclusion chromatography is used to prove and quantify the adsorption of pS-b-EP onto the Pickering emulsion droplets. A maximum surface coverage of 1.3 mg/m(2) is obtained after 2 h, which is approximately one-third of the adsorption on a pure pS surface. We believe that the presence of polar sulfate groups on the particle, which initially stabilized the particle in water, reduces the adsorption of pS-b-EP. Microcapsules are formed by heating the Pickering emulsion above the glass-transition temperature of the particles. Significant aggregation is observed, if no pS-b-EP is used. The adsorption of pS-b-EP provides steric stabilization to the Pickering emulsion droplets, reduces aggregation significantly, and ultimately leads to the successful and efficient synthesis of pS microcapsules.

  9. Nepenthes khasiana mediated synthesis of stabilized gold nanoparticles: Characterization and biocompatibility studies.

    PubMed

    Dhamecha, Dinesh; Jalalpure, Sunil; Jadhav, Kiran

    2016-01-01

    The current study summarizes a unique green process for the synthesis of gold nanoparticles by simple treatment of gold salts with aqueous extract of Nepenthes khasiana (NK)--a red listed medicinal plant and its characterization. Study on the effect of different process parameters like temperature, pH and stirring on surface and stability characteristics has been demonstrated. Formation of GNPs was visually observed by change in color from colorless to wine red and characterized by UV-Visible spectroscopy, FT-IR spectroscopy, Zetasizer, X-RD, ICP-AES, SEM-EDAX, AFM and TEM. In vitro stability studies of gold colloidal dispersion in various blood components suggest that, NK mediated GNPs exhibit remarkable in vitro stability in 2% bovine serum albumin, 2% human serum albumin (HSA), 0.2M histidine, and 0.2M cysteine but unstable in 5% NaCl solution and acidic pH. Biocompatibility of NK stabilized GNPs against normal mouse fibroblasts (L929) cell lines revealed nontoxic nature of GNPs and thus provides exceptional opportunities for their uses as nanomedicine for diagnosis and drug therapy. The role of antioxidant phytochemicals (flavonoids and polyphenols) of NK extract in synthesis of biocompatible and stabilized GNPs was demonstrated by estimating total flavonoid content, total phenolic content and total antioxidant capacity of extract before and after formation of GNPs. Fast and easy synthesis of biocompatible GNPs possesses unique physical and chemical features which serve as an advantage for its use in various biomedical applications. The overall approach designated in the present research investigation for the synthesis of GNPs is based on all 12 principles of green chemistry, in which no man-made chemical other than the gold chloride was used.

  10. Fire effects on soil aggregate stability: a review and synthesis

    NASA Astrophysics Data System (ADS)

    Mataix-Solera, J.; Cerdà, A.; Arcenegui, V.; Jordán, A.; Zavala, L. M.

    2012-04-01

    Fire can affect soil properties depending on a number of factors including fire severity and soil type. Aggregate stability (AS) refers to soil structure resilience in response to external mechanical forces. Many authors consider soil aggregation to be a parameter reflecting soil health, as it depends on chemical, physical and biological factors. The response of AS to forest fires is complex, since it depends on how fire has affected other related properties such as organic matter content, soil microbiology, water repellency and soil mineralogy. Opinions differ concerning the effect of fire on AS. Some authors have observed a decrease in AS in soils affected by intense wildfire or severe laboratory heating. However, others have reported increases. We provide an up to date review of the research on this topic and an analysis of the causes for the different effects observed. The implications for soil system functioning and for the hydrology of the affected areas are also discussed. Generally, low severity fires do not produce notable changes in AS, although in some cases an increase has been observed and attributed to increased water repellency. In contrast, high severity fires can induce important changes in this property, but with different effects depending on the type of soil affected. The patterns observed can vary from a disaggregation as a consequence of the organic matter destruction, to a strong aggregation if a recrystallization of some minerals such as Fe and Al oxyhydroxides occurs when they are present in sufficient quantities in the soil, after exposure to high temperatures. Because of the complexity of the different possible effects and reasons for the potential changes in the fire-affected soil aggregates, the inclusion of other parameters in the studies is necessary to understand the results. The suggested parameters to include in the examination of AS are: soil organic matter, microbial biomass, water repellency, texture, aggregate size distribution

  11. Synthesis of stabilized myrrh-capped hydrocolloidal magnetite nanoparticles.

    PubMed

    Atta, Ayman M; Al-Lohedan, Hamad A; Al-Hussain, Sami A

    2014-01-01

    Herein we report a new method for synthesizing stabilized magnetic nanoparticle (MNP) colloids. A new class of monodisperse water-soluble magnetite nano-particles was prepared by a simple and inexpensive co-precipitation method. Iron ions and iodine were prepared by the reaction between ferric chloride and potassium iodide. The ferrous and ferric ions were hydrolyzed at low temperature at pH 9 in the presence of iodine to produce iron oxide nanoparticles. The natural product myrrh gum was used as capping agent to produce highly dispersed coated magnetite nanoparticles. The structure and morphology of the magnetic nanogel was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM), and X-ray diffraction (XRD) was used to examine the crystal structure of the produced magnetite nanoparticles. PMID:25090117

  12. Synthesis of stabilized myrrh-capped hydrocolloidal magnetite nanoparticles.

    PubMed

    Atta, Ayman M; Al-Lohedan, Hamad A; Al-Hussain, Sami A

    2014-07-31

    Herein we report a new method for synthesizing stabilized magnetic nanoparticle (MNP) colloids. A new class of monodisperse water-soluble magnetite nano-particles was prepared by a simple and inexpensive co-precipitation method. Iron ions and iodine were prepared by the reaction between ferric chloride and potassium iodide. The ferrous and ferric ions were hydrolyzed at low temperature at pH 9 in the presence of iodine to produce iron oxide nanoparticles. The natural product myrrh gum was used as capping agent to produce highly dispersed coated magnetite nanoparticles. The structure and morphology of the magnetic nanogel was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM), and X-ray diffraction (XRD) was used to examine the crystal structure of the produced magnetite nanoparticles.

  13. Synthesis of chitosan-stabilized gold nanoparticles by atmospheric plasma.

    PubMed

    Jin, Yong; Li, Zepeng; Hu, Lijuan; Shi, Xiaowen; Guan, Weimin; Du, Yumin

    2013-01-01

    We report a facile method to prepare gold nanoparticles by atmospheric plasma. Chitosan, was used as a stabilizing agent and gold precursor. In chitosan solution was reduced by atmospheric plasma at room temperature. We find the plasma treatment is effective for reducing the gold precursor and the process only takes minutes. The obtained gold nanoparticles were characterized with UV-vis spectroscopy and transmission electron microscopy. The results indicated that the morphology and size distribution of gold nanoparticles prepared varied with treatment time and the ratio of chitosan to precursor metal salts. Additionally, a preliminary study on air component analysis indicated that the moisture in air plays an important role in producing the active ingredient for the production of gold nanoparticles.

  14. Synthesis and characterization of processable polyimides with enhanced thermal stability

    NASA Technical Reports Server (NTRS)

    Harris, Frank W.

    1987-01-01

    Many of the emerging applications of polymers on space vehicles require materials with outstanding thermal stability. These polymers must also be readily processable in order to facilitate their use. The syntheses and polymerization of a cardo dianhydride were investigated. This monomer was prepared via the reaction of N-methyl 4-nitrophthalimide with a cardo diol. Polyimides containing oxyalkylene linkages were studied. The effects of two additional structural modifications on the polymers' properties were investigated. The effects of carrying out the preparation of poly(amic acid)s under non-equilibrium conditions were examined. Approaches that were investigated included the in-situ neutralization of the generated amic acid and its in-situ esterification.

  15. Sterically stabilized water based magnetic fluids: Synthesis, structure and properties

    NASA Astrophysics Data System (ADS)

    Bica, Doina; Vékás, Ladislau; Avdeev, Mikhail V.; Marinică, Oana; Socoliuc, Vlad; Bălăsoiu, Maria; Garamus, Vasil M.

    2007-04-01

    Magnetic fluids (MFs), prepared by chemical co-precipitation followed by double layer steric and electrostatic (combined) stabilization of magnetite nanoparticles dispersed in water, are presented. Several combinations of surfactants with different chain lengths (lauric acid (LA), myristic acid (MA), oleic acid (OA) and dodecyl-benzene-sulphonic acid (DBS)) were used, such as LA+LA, MA+MA, LA+DBS, MA+DBS, OA+DBS, OA+OA and DBS+DBS. Static light scattering, transmission electron microscopy, small angle neutron scattering, magnetic and magneto-rheological measurements revealed that MFs with MA+MA or LA+LA biocompatible double layer covered magnetite nanoparticles are the most stable colloidal systems among the investigated samples, and thus suitable for biomedical applications.

  16. Ligand Effects on Synthesis and Post-Synthetic Stability of PbSe Nanocrystals

    SciTech Connect

    Dai, Quanqin; Zhang, Yu; Wang, Yingnan; Hu, Michael Z.

    2010-01-01

    This paper reports the effect of ligands including oleic acid (OA), trioctylphosphine (TOP), and tributylphosphine (TBP) on the PbSe nanocrystal growth during synthesis, as well as the effect of OA ligands on the nanocrystal stability after synthesis. These ligands play important roles in the nucleation and growth mechanism of nanocrystals. We have discovered that the ligand effect on the growth of PbSe nanocrystals can differ from that on the mostly studied CdSe nanocrystals. Also, we present a method for producing relatively smaller and more monodisperse PbSe nanocrystals based on our new understanding that the use of TBP, instead of the generally reported TOP, can slow down the growth of PbSe nanocrystals. In addition, our postsynthetic investigation of OA ligand effects demonstrate the dominant desorption of OA-bonded Pb atoms, causing the shrinkage of PbSe nanocrystals. This provides some insight into stabilization strategies for labile PbSe nanocrystals.

  17. Synthesis, thermal stability, and photocatalytic activity of nanocrystalline titanium carbide

    SciTech Connect

    Chen, Youjian; Zhang, Hong; Ma, DeKun; Ma, Jianhua; Ye, Hongnan; Qian, Gaojin; Ye, Yi

    2011-11-15

    Highlights: {yields} The synthesized temperature is lower than some conventional methods. {yields} These raw materials are safe; all manipulations are rather safe and convenient. {yields} The product exhibits photocatalytic activity in degradation of Rhodamine-B. -- Abstract: Titanium carbide (TiC) was prepared via one simple route by the reaction of metallic magnesium powders with titanium dioxide (TiO{sub 2}) and potassium acetate (CH{sub 3}COOK) in an autoclave at 600 {sup o}C and 8 h. Phase structure and morphology were characterized by X-ray powder diffraction (XRD) and Scanning electron microscopy (SEM). The results indicated that the product was cubic TiC, which consisted of particles with an average size of about 100 nm in diameter. The product was also studied by the thermogravimetric analysis (TGA) and its photocatalysis. It had good thermal stability and oxidation resistance below 350 {sup o}C in air. In addition, we discovered that the cubic TiC powders exhibited photocatalytic activity in degradation of Rhodamine-B (RhB) under 500 W mercury lamp light irradiation.

  18. Controlled synthesis and thermal stability of hydroxyapatite hierarchical microstructures

    SciTech Connect

    Sun, Ruixue; Chen, Kezheng; Liao, Zhongmiao; Meng, Nan

    2013-03-15

    Highlights: ► Hydroxyapatite hierarchical microstructures have been synthesized by a facile method. ► The morphology and size of the building units of 3D structures can be controlled. ► The hydroxyapatite with 3D structure is morphologically and structurally stable up to 800 °C. - Abstract: Hydroxyapatite (HAp) hierarchical microstructures with novel 3D morphology were prepared through a template- and surfactant-free hydrothermal homogeneous precipitation method. Field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) were used to characterize the morphology and composition of the synthesized products. Interestingly, the obtained HAp with 3D structure is composed of one-dimensional (1D) nanorods or two-dimensional (2D) nanoribbons, and the length and morphology of these building blocks can be controlled through controlling the pH of the reaction. The building blocks are single crystalline and have different preferential orientation growth under different pH conditions. At low pH values, octacalcium phosphate (OCP) phase formed first and then transformed into HAp phase due to the increased pH value caused by the decomposition of urea. The investigation on the thermal stability reveals that the prepared HAp hierarchical microstructures are morphologically and structurally stable up to 800 °C.

  19. Synthesis and Stability of Iron Nanoparticles for Lunar Environment Studies

    NASA Technical Reports Server (NTRS)

    Hung, Ching-cheh; McNatt, Jeremiah

    2009-01-01

    Simulant of lunar dust is needed when researching the lunar environment. However, unlike the true lunar dust, today s simulants do not contain nanophase iron. Two different processes have been developed to fabricate nanophase iron to be used as part of the lunar dust simulant: (1) Sequentially treating a mixture of ferric chloride, fluorinated carbon, and soda lime glass beads at about 300 C in nitrogen, at room temperature in air, and then at 1050 C in nitrogen. The product includes glass beads that are grey in color, can be attracted by a magnet, and contain alpha-iron nanoparticles (which seem to slowly lose their lattice structure in ambient air during a period of 12 months). This product may have some similarity to the lunar glassy regolith that contains Fe(sup 0). (2) Heating a mixture of carbon black and a lunar simulant (a mixed metal oxide that includes iron oxide) at 1050 C in nitrogen. This process simulates lunar dust reaction to the carbon in a micrometeorite at the time of impact. The product contains a chemically modified simulant that can be attracted by a magnet and has a surface layer whose iron concentration increased during the reaction. The iron was found to be alpha-iron and Fe3O4 nanoparticles, which appear to grow after the fabrication process, but stabilizes after 6 months of ambient air storage.

  20. Shape-controlled synthesis of NIR absorbing branched gold nanoparticles and morphology stabilization with alkanethiols.

    PubMed

    Van de Broek, B; Frederix, F; Bonroy, K; Jans, H; Jans, K; Borghs, G; Maes, G

    2011-01-01

    Gold nanoparticles are ideal candidates for clinical applications if their plasmon absorption band is situated in the near infrared region (NIR) of the electromagnetic spectrum. Various parameters, including the nanoparticle shape, strongly influence the position of this absorption band. The aim of this study is to produce stabilized NIR absorbing branched gold nanoparticles with potential for biomedical applications. Hereto, the synthesis procedure for branched gold nanoparticles is optimized varying the different synthesis parameters. By subsequent electroless gold plating the plasmon absorption band is shifted to 747.2 nm. The intrinsic unstable nature of the nanoparticles' morphology can be clearly observed by a spectral shift and limits their use in real applications. However, in this article we show how the stabilization of the branched structure can be successfully achieved by exchanging the initial capping agent for different alkanethiols and disulfides. Furthermore, when using alkanethiols/disulfides with poly(ethylene oxide) units incorporated, an increased stability of the gold nanoparticles is achieved in high salt concentrations up to 1 M and in a cell culture medium. These achievements open a plethora of opportunities for these stabilized branched gold nanoparticles in nanomedicine.

  1. Shape-controlled synthesis of NIR absorbing branched gold nanoparticles and morphology stabilization with alkanethiols

    NASA Astrophysics Data System (ADS)

    Van de Broek, B.; Frederix, F.; Bonroy, K.; Jans, H.; Jans, K.; Borghs, G.; Maes, G.

    2011-01-01

    Gold nanoparticles are ideal candidates for clinical applications if their plasmon absorption band is situated in the near infrared region (NIR) of the electromagnetic spectrum. Various parameters, including the nanoparticle shape, strongly influence the position of this absorption band. The aim of this study is to produce stabilized NIR absorbing branched gold nanoparticles with potential for biomedical applications. Hereto, the synthesis procedure for branched gold nanoparticles is optimized varying the different synthesis parameters. By subsequent electroless gold plating the plasmon absorption band is shifted to 747.2 nm. The intrinsic unstable nature of the nanoparticles' morphology can be clearly observed by a spectral shift and limits their use in real applications. However, in this article we show how the stabilization of the branched structure can be successfully achieved by exchanging the initial capping agent for different alkanethiols and disulfides. Furthermore, when using alkanethiols/disulfides with poly(ethylene oxide) units incorporated, an increased stability of the gold nanoparticles is achieved in high salt concentrations up to 1 M and in a cell culture medium. These achievements open a plethora of opportunities for these stabilized branched gold nanoparticles in nanomedicine.

  2. Synthesis, characterization and application of enrofloxacin complexes as thermal stabilizers for rigid poly(vinyl chloride).

    PubMed

    el-Gamel, Nadia E A; Mohamed, Riham R; Zayed, M A

    2012-02-14

    Synthesis and characterization of both binary Co(II)- (1), Ni(II)- (2) complexes with enrofloxacin drug (HL(1)) and ternary Co(II)- (3), Ni(II)- (4) complexes in presence of DL-alanine (H(2)L(2)) are reported using physico-chemical techniques. The antimicrobial activity of these complexes has been screened against two gram-positive and two gram-negative bacteria. Antifungal activity against two different fungi has been evaluated and compared with reference drug. All the binary and ternary complexes showed remarkable potential antimicrobial activity higher than the recommended standard agents. Ni(II)-complexes exhibited higher potency as compared to the parent drug against bacterial and fungal strain. In addition, it was of interest to investigate the reported complexes as thermal stabilizers and co-stabilizers for rigid PVC in air at 180 °C. Their high stabilizing efficiency is detected by their high induction period values (T(s)) compared with some of the common reference stabilizers used industrially, such as dibasic lead carbonate (DBLC) and calcium-zinc soap. Blending these complexes with some of the reference stabilizers in different ratios had a synergistic effect on both induction period as it gave better thermal stability and lower extent of discoloration. The stabilizing efficiency is attributed at least partially to the ability of the metal complex stabilizer to be incorporated in the polymeric chains, thus disrupting the chain degradation and replace the labile chlorine atoms on PVC chains by a relatively more s moiety of the inorganic stabilizer. Their amenability to use as a biomedical additives for PVC, has afforded them great potential for various medical applications. PMID:22159190

  3. Coordinated regulation of synthesis and stability of RNA during the acute TNF-induced proinflammatory response

    PubMed Central

    Paulsen, Michelle T.; Veloso, Artur; Prasad, Jayendra; Bedi, Karan; Ljungman, Emily A.; Tsan, Ya-Chun; Chang, Ching-Wei; Tarrier, Brendan; Washburn, Joseph G.; Lyons, Robert; Robinson, Daniel R.; Kumar-Sinha, Chandan; Wilson, Thomas E.; Ljungman, Mats

    2013-01-01

    Steady-state gene expression is a coordination of synthesis and decay of RNA through epigenetic regulation, transcription factors, micro RNAs (miRNAs), and RNA-binding proteins. Here, we present bromouride labeling and sequencing (Bru-Seq) and bromouridine pulse-chase and sequencing (BruChase-Seq) to assess genome-wide changes to RNA synthesis and stability in human fibroblasts at homeostasis and after exposure to the proinflammatory tumor necrosis factor (TNF). The inflammatory response in human cells involves rapid and dramatic changes in gene expression, and the Bru-Seq and BruChase-Seq techniques revealed a coordinated and complex regulation of gene expression both at the transcriptional and posttranscriptional levels. The combinatory analysis of both RNA synthesis and stability using Bru-Seq and BruChase-Seq allows for a much deeper understanding of mechanisms of gene regulation than afforded by the analysis of steady-state total RNA and should be useful in many biological settings. PMID:23345452

  4. [Poly (allylamine)-stabilized colloidal copper nanoparticles: synthesis and their SERS activities].

    PubMed

    Wang, Yan-Fei; Xiao, Zhan-Min; Zhang, Chun-Guang

    2012-06-01

    Poly(allylamine)-stabilized spherical and rod-shaped copper nanoparticles were synthesized by a simple chemical reaction. The synthesis was performed by the reduction of copper (II) salt with hydrazine in aqueous solution under atmospheric air in the presence of poly(allylamine) (PAAm) capping agent. Besides providing long-term stability to the nanoparticles by preventing particle agglomeration, polymer capping agents such as PAAm make the particles dispersible in aqueous solution. Noteworthy advantages of the synthetic method include its production of water dispersible nanoparticles at room temperature without inert atmosphere, making the synthesis more environmentally friendly. The resulting copper nanoparticles were investigated by UV-Vis spectroscopy and transmission electron microscopy. The authors found that several factors, including the amount of NaOH solution, concentration of PAAm, and reaction time, affect the composition, size, morphology, and degree of agglomeration of the resulting copper nanoparticles. The amount of NaOH in the reaction is crucial for the synthesis to result in either pure copper or copper oxide-containing copper nanoparticles as well as to produce the highest possible yield of copper nanoparticles. In addition, the reaction time and concentration of PAAm play key roles in controlling the size and shape of the nanoparticles, respectively. The resulting colloidal copper nanoparticles exhibit large surface-enhanced Raman spectroscopy (SERS) signals. PMID:22870639

  5. Novel LLM series high density energy materials: Synthesis, characterization, and thermal stability

    NASA Astrophysics Data System (ADS)

    Pagoria, Philip; Zhang, Maoxi; Tsyshevskiy, Roman; Kuklja, Maija

    Novel high density energy materials must satisfy specific requirements, such as an increased performance, reliably high stability to external stimuli, cost-efficiency and ease of synthesis, be environmentally benign, and be safe for handling and transportation. During the last decade, the attention of researchers has drifted from widely used nitroester-, nitramine-, and nitroaromatic-based explosives to nitrogen-rich heterocyclic compounds. Good thermal stability, the low melting point, high density, and moderate sensitivity make heterocycle materials attractive candidates for use as oxidizers in rocket propellants and fuels, secondary explosives, and possibly as melt-castable ingredients of high explosive formulations. In this report, the synthesis, characterization, and results of quantum-chemical DFT study of thermal stability of LLM-191, LLM-192 and LLM-200 high density energy materials are presented. Work performed under the auspices of the DOE by the LLNL (Contract DE-AC52-07NA27344). This research is supported in part by ONR (Grant N00014-12-1-0529) and NSF. We used NSF XSEDE (Grant DMR-130077) and DOE NERSC (Contract DE-AC02-05CH11231) resources.

  6. TATA boxes in gene transcription and poly (A) tails in mRNA stability: New perspective on the effects of berberine

    PubMed Central

    Yuan, Zhi-Yi; Lu, Xi; Lei, Fan; Chai, Yu-Shuang; Wang, Yu-Gang; Jiang, Jing-Fei; Feng, Tian-Shi; Wang, Xin-Pei; Yu, Xuan; Yan, Xiao-Jin; Xing, Dong-Ming; Du, Li-Jun

    2015-01-01

    Berberine (BBR) is a natural compound with variable pharmacological effects and a broad panel of target genes. We investigated berberine’s pharmacological activities from the perspective of its nucleotide-binding ability and discovered that BBR directly regulates gene expression by targeting TATA boxes in transcriptional regulatory regions as well as the poly adenine (poly (A)) tail at the mRNA terminus. BBR inhibits gene transcription by binding the TATA boxes in the transcriptional regulatory region, but it promotes higher levels of expression by targeting the poly (A) tails of mRNAs. The present study demonstrates that TATA boxes and poly (A) tails are the first and second primary targets by which BBR regulates gene expression. The final outcome of gene regulation by BBR depends on the structure of the individual gene. This is the first study to reveal that TATA boxes and poly (A) tails are direct targets for BBR in its regulation of gene expression. Our findings provide a novel explanation for the complex activities of a small molecule compound in a biological system and a novel horizon for small molecule-compound pharmacological studies. PMID:26671652

  7. Synthesis, solubility, plasma stability, and pharmacological evaluation of novel sulfonylhydrazones designed as anti-diabetic agents

    PubMed Central

    Zapata-Sudo, Gisele; da Costa Nunes, Isabelle Karine; Araujo, Josenildo Segundo Chaves; da Silva, Jaqueline Soares; Trachez, Margarete Manhães; da Silva, Tiago Fernandes; da Costa, Filipe P; Sudo, Roberto Takashi; Barreiro, Eliezer J; Lima, Lídia Moreira

    2016-01-01

    Neuropathy is a serious complication of diabetes that has a significant socioeconomic impact, since it frequently demands high levels of health care consumption and compromises labor productivity. Recently, LASSBio-1471 (3) was demonstrated to improve oral glucose tolerance, reduce blood glucose levels, and display an anti-neuropathy effect in a murine streptozotocin-induced diabetes model. In the present work, we describe the design, synthesis, solubility, plasma stability, and pharmacological evaluation of novel sulfonylhydrazone derivatives (referred to herein as compounds 4–9), which were designed by molecular modification based on the structure of the prototype LASSBio-1471 (3). Among the compounds tested, better plasma stability was observed with 4, 5, and 9 in comparison to compounds 6, 7, and 8. LASSBio-1773 (7), promoted not only hypoglycemic activity but also the reduction of thermal hyperalgesia and mechanical allodynia in a murine model of streptozotocin-induced diabetic neuropathic pain. PMID:27672310

  8. Synthesis, solubility, plasma stability, and pharmacological evaluation of novel sulfonylhydrazones designed as anti-diabetic agents

    PubMed Central

    Zapata-Sudo, Gisele; da Costa Nunes, Isabelle Karine; Araujo, Josenildo Segundo Chaves; da Silva, Jaqueline Soares; Trachez, Margarete Manhães; da Silva, Tiago Fernandes; da Costa, Filipe P; Sudo, Roberto Takashi; Barreiro, Eliezer J; Lima, Lídia Moreira

    2016-01-01

    Neuropathy is a serious complication of diabetes that has a significant socioeconomic impact, since it frequently demands high levels of health care consumption and compromises labor productivity. Recently, LASSBio-1471 (3) was demonstrated to improve oral glucose tolerance, reduce blood glucose levels, and display an anti-neuropathy effect in a murine streptozotocin-induced diabetes model. In the present work, we describe the design, synthesis, solubility, plasma stability, and pharmacological evaluation of novel sulfonylhydrazone derivatives (referred to herein as compounds 4–9), which were designed by molecular modification based on the structure of the prototype LASSBio-1471 (3). Among the compounds tested, better plasma stability was observed with 4, 5, and 9 in comparison to compounds 6, 7, and 8. LASSBio-1773 (7), promoted not only hypoglycemic activity but also the reduction of thermal hyperalgesia and mechanical allodynia in a murine model of streptozotocin-induced diabetic neuropathic pain.

  9. Stability of the human polymerase δ holoenzyme and its implications in lagging strand DNA synthesis.

    PubMed

    Hedglin, Mark; Pandey, Binod; Benkovic, Stephen J

    2016-03-29

    In eukaryotes, DNA polymerase δ (pol δ) is responsible for replicating the lagging strand template and anchors to the proliferating cell nuclear antigen (PCNA) sliding clamp to form a holoenzyme. The stability of this complex is integral to every aspect of lagging strand replication. Most of our understanding comes from Saccharomyces cerevisae where the extreme stability of the pol δ holoenzyme ensures that every nucleobase within an Okazaki fragment is faithfully duplicated before dissociation but also necessitates an active displacement mechanism for polymerase recycling and exchange. However, the stability of the human pol δ holoenzyme is unknown. We designed unique kinetic assays to analyze the processivity and stability of the pol δ holoenzyme. Surprisingly, the results indicate that human pol δ maintains a loose association with PCNA while replicating DNA. Such behavior has profound implications on Okazaki fragment synthesis in humans as it limits the processivity of pol δ on undamaged DNA and promotes the rapid dissociation of pol δ from PCNA on stalling at a DNA lesion.

  10. Synthesis of Yttria-Stabilized Zirconia Aerogels by a Non-Alkoxide Sol-Gel Route

    SciTech Connect

    Chervin, C N; Clapsaddle, B J; Chiu, H W; Gash, A E; Satcher, Jr., J H; Kauzlarich, S M

    2005-02-11

    Homogeneous, nanocrystalline powders of yttria-stabilized zirconia were prepared using a nonalkoxide sol-gel method. Monolithic gels, free of precipitation, were prepared by addition of propylene oxide to aqueous solutions of Zr{sup 4+} and Y{sup 3+} chlorides at room temperature. The gels were dried with supercritical CO{sub 2}(l), resulting in amorphous aerogels that crystallized into cubic stabilized ZrO{sub 2} following calcination at 500 C. The aerogels and resulting crystalline products were characterized using in-situ temperature profile X-ray diffraction, thermal analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and nitrogen adsorption/desorption analysis. TEM and N{sub 2} adsorption/desorption analysis of an aerogel indicated a porous network structure with a high surface area (409 m{sup 2}/g). The crystallized yttria-stabilized zirconia maintained high surface area (159 m{sup 2}/g) upon formation of homogeneous, nanoparticles ({approx}10 nm). Ionic conductivity at 1000 C of sintered YSZ (1500 C, 3 hours) prepared by this method, was 0.13 {+-} 0.02 {Omega}{sup -1} cm{sup -1}. Activation energies for the conduction processes from 1000-550 C and 550-400 C, were 0.95 {+-} 0.09 and 1.12 {+-} 0.05 eV, respectively. This is the first reported synthesis and characterization of yttria-stabilized zirconia via an aerogel precursor.

  11. Organic-Stabilizer-Free Polyol Synthesis of Silver Nanowires for Electrode Applications.

    PubMed

    Sim, Hwansu; Bok, Shingyu; Kim, Bongsung; Kim, Minha; Lim, Guh-Hwan; Cho, Sung Min; Lim, Byungkwon

    2016-09-19

    The polyol reduction of a Ag precursor in the presence of an organic stabilizer, such as poly(vinylpyrrolidone), is a widely used method for the production of Ag nanowires (NWs). However, organic capping molecules introduce insulating layers around each NW. Herein we demonstrate that Ag NWs can be produced in high yield without any organic stabilizers simply by introducing trace amounts of NaCl and Fe(NO3 )3 during low-temperature polyol synthesis. The heterogeneous nucleation and growth of Ag NWs on initially formed AgCl particles, combined with oxidative etching of unwanted Ag nanoparticles, resulted in the selective formation of long NWs with an average length of about 40 μm in the absence of a capping or stabilizing effect provided by surface-adsorbing molecules. These organic-stabilizer-free Ag NWs were directly used for the fabrication of high-performance transparent or stretchable electrodes without a complicated process for the removal of capping molecules from the NW surface. PMID:27571578

  12. Organic-Stabilizer-Free Polyol Synthesis of Silver Nanowires for Electrode Applications.

    PubMed

    Sim, Hwansu; Bok, Shingyu; Kim, Bongsung; Kim, Minha; Lim, Guh-Hwan; Cho, Sung Min; Lim, Byungkwon

    2016-09-19

    The polyol reduction of a Ag precursor in the presence of an organic stabilizer, such as poly(vinylpyrrolidone), is a widely used method for the production of Ag nanowires (NWs). However, organic capping molecules introduce insulating layers around each NW. Herein we demonstrate that Ag NWs can be produced in high yield without any organic stabilizers simply by introducing trace amounts of NaCl and Fe(NO3 )3 during low-temperature polyol synthesis. The heterogeneous nucleation and growth of Ag NWs on initially formed AgCl particles, combined with oxidative etching of unwanted Ag nanoparticles, resulted in the selective formation of long NWs with an average length of about 40 μm in the absence of a capping or stabilizing effect provided by surface-adsorbing molecules. These organic-stabilizer-free Ag NWs were directly used for the fabrication of high-performance transparent or stretchable electrodes without a complicated process for the removal of capping molecules from the NW surface.

  13. Green Synthesis of Silver Nanoparticles: Effect of Dextran Molecular Weight Used as Stabilizing-Reducing Agent.

    PubMed

    Carré-Rangel, Luceldi; Alonso-Nuñez, Gabriel; Espinoza-Gómez, Heriberto; Flores-López, Lucía Z

    2015-12-01

    This paper describes an easy green chemistry method for the synthesis of silver nanoparticles (AgNPs). The AgNPs were obtained through the use of an aqueous silver nitrate solution (AgNO3), with dextrans aqueous solutions of different molecular weights acting as stabilizing and reducing agent, employing the chemical reduction method. We made a comparative study to determine which molecular weight dextran was the best stabilizing and reducing agent, and it was found that the molecular size of the stabilizing agent is inversely proportional to the size of the nanoparticle synthesized. The formation of the AgNPs was demonstrated by UV-Vis spectroscopy, atomic force microscopy (AFM), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). SEM-EDS analysis shows the formation of particles with dendritic structure. TEM shows nanoparticles which are spherical in shape and 1-10 nm in size; also, the clear lattice fringes show highly crystalline AgNPs (FCC). PMID:26682423

  14. Biocompatible transferrin-conjugated sodium hexametaphosphate-stabilized gold nanoparticles: synthesis, characterization, cytotoxicity and cellular uptake

    NASA Astrophysics Data System (ADS)

    Parab, Harshala J.; Huang, Jing-Hong; Lai, Tsung-Ching; Jan, Yi-Hua; Liu, Ru-Shi; Wang, Jui-Ling; Hsiao, Michael; Chen, Chung-Hsuan; Hwu, Yeu-Kuang; Tsai, Din Ping; Chuang, Shih-Yi; Pang, Jong-Hwei S.

    2011-09-01

    The feasibility of using gold nanoparticles (AuNPs) for biomedical applications has led to considerable interest in the development of novel synthetic protocols and surface modification strategies for AuNPs to produce biocompatible molecular probes. This investigation is, to our knowledge, the first to elucidate the synthesis and characterization of sodium hexametaphosphate (HMP)-stabilized gold nanoparticles (Au-HMP) in an aqueous medium. The role of HMP, a food additive, as a polymeric stabilizing and protecting agent for AuNPs is elucidated. The surface modification of Au-HMP nanoparticles was carried out using polyethylene glycol and transferrin to produce molecular probes for possible clinical applications. In vitro cell viability studies performed using as-synthesized Au-HMP nanoparticles and their surface-modified counterparts reveal the biocompatibility of the nanoparticles. The transferrin-conjugated nanoparticles have significantly higher cellular uptake in J5 cells (liver cancer cells) than control cells (oral mucosa fibroblast cells), as determined by inductively coupled plasma mass spectrometry. This study demonstrates the possibility of using an inexpensive and non-toxic food additive, HMP, as a stabilizer in the large-scale generation of biocompatible and monodispersed AuNPs, which may have future diagnostic and therapeutic applications.

  15. Synthesis of netlike gold nanoparticles using ampicillin as a stabilizing reagent and its application

    SciTech Connect

    Song, Y.Z.; Zhou, J.F.; Song, Y.; Cheng, Z.P.; Xu, J.

    2012-12-15

    Graphical abstract: Electrochemical deposition of netlike gold nanoparticles (GNPs) on the surface of glassy carbon electrode and preparation of netlike GNPs in aqueous solution using ampicillin as a stabilizing reagent were proposed. The catalytic properties of netlike gold nanoparticles on the glassy carbon electrode for dopamine were demonstrated. The results indicate that the netlike gold nanoparticle modified electrode has an excellent repeatability and reproducibility. Display Omitted Highlights: ► Synthesis of netlike gold nanoparticles using ampicillin as a stabilizing reagent. ► Excellent repeatability and reproducibility of netlike gold nanoparticle modified glassy carbon electrode. ► The catalytic properties of netlike gold nanoparticle for dopamine. -- Abstract: Electrochemical deposition of netlike gold nanoparticles on the surface of glassy carbon electrode and preparation of netlike GNPs in aqueous solution using ampicillin as a stabilizing reagent were proposed. The netlike gold nanoparticles were characterized by scanning electron microscope, transmission electron microscope, infrared spectrometer, UV spectrophotometer, powder X-ray diffractometer and electrochemical analyzer. The catalysis of the netlike gold nanoparticles on the glassy carbon electrode for dopamine was demonstrated. The results indicate that the gold nanoparticle modified electrode has an excellent repeatability and reproducibility.

  16. Si=Si Double Bonds: Synthesis of an NHC-Stabilized Disilavinylidene.

    PubMed

    Ghana, Priyabrata; Arz, Marius I; Das, Ujjal; Schnakenburg, Gregor; Filippou, Alexander C

    2015-08-17

    An efficient two-step synthesis of the first NHC-stabilized disilavinylidene (Z)-(SIdipp)Si=Si(Br)Tbb (2; SIdipp=C[N(C6H3-2,6-iPr2)CH2]2, Tbb=C6H2-2,6-[CH(SiMe3)2]2-4-tBu, NHC=N-heterocyclic carbene) is reported. The first step of the procedure involved a 2:1 reaction of SiBr2(SIdipp) with the 1,2-dibromodisilene (E)-Tbb(Br)Si=Si(Br)Tbb at 100 °C, which afforded selectively an unprecedented NHC-stabilized bromo(silyl)silylene, namely SiBr(SiBr2Tbb)(SIdipp) (1). Alternatively, compound 1 could be obtained from the 2:1 reaction of SiBr2(SIdipp) with LiTbb at low temperature. 1 was then selectively reduced with C8K to give the NHC-stabilized disilavinylidene 2. Both low-valent silicon compounds were comprehensively characterized by X-ray diffraction analysis, multinuclear NMR spectroscopy, and elemental analyses. Additionally, the electronic structure of 2 was studied by various quantum-chemical methods. PMID:26136260

  17. Synthesis of "group polysaccharide" by membranes from Streptococcus pyogenes and its stabilized L-form.

    PubMed Central

    Reusch, V M; Panos, C

    1977-01-01

    Rhamnose and N-acetylglucosamine (GlcNAc) are incorporated from thymidine 5'-diphosphorhamnose and uridine 5-diphospho-N-acetylglucosamine (UDPGlcNAc) into membrane fragments prepared from Streptococcus pyogenes but not into membrane fragements prepared from a stabilized L-form of this organism. Incorporation from TDPrhamnose is partially dependent upon UDPGlcNAc and vice versa. The oligomeric GlcNAc and rhamonose-containing products are easily extracted from membrane particles by sedimentation through detergent solutions. They are substantially extracted into methanol but not into chloroform-methanol (2:1). When product containing both radioactive rhamnose and GlcNAc is deacetylated and hydrolyzed briefy in acid, glucosaminyl rhamnose is obtained, byt not higher oligomers, suggesting that oligomer synthesis in vitro is terminated because unidentified wnzymatic requirements are not satisfied. The data are consistent with the assembly of group A-specific polysaccharide at the cellular membrane with participation of a lipoid anchor (acceptor) molecule. PMID:321425

  18. Synthesis of tritium labelled endomorphin II and its stability in the radioreceptor assay

    NASA Astrophysics Data System (ADS)

    Tömböly, Cs.; Spetea, M.; Borsodi, A.; Tóth, G.

    1999-01-01

    Endomorphine I (Tyr-Pro-Trp-Phe-NH2) and endomorphin II (Tyr-Pro-Phe-Phe-NH2) are recently isolated neuropeptides. They have the highest specificity and affinity for the μ-opiate receptor among all the endogenous substances so far described, and they may be natural ligands for this receptor [1]. We prepared the [3H] endomorphin II with high specific radioactivity (53.4 Ci/mmol) by catalytic dehalotritiation. The precursor [(3,5-I2)Tyr1]-endomorphin II was synthesized by solid phase peptide synthesis using Boc chemistry. Labelled endomorphin II was used to investigate its binding properties in rat brain membrane. The stability of [3H]endomorphin II toward enzymatic degradation in membrane preparation was examined by RP-HPLC and by using a radioactivity detector.

  19. Synthesis of fibrinolytic active silver nanoparticle using wheat bran xylan as a reducing and stabilizing agent.

    PubMed

    Harish, B S; Uppuluri, Kiran Babu; Anbazhagan, Veerappan

    2015-11-01

    A facile synthesis of highly stable silver nanoparticles (AgNPs) was reported using a biopolymer, xylan as both a reducing and stabilizing agent. Xylan was isolated from waste biomass, wheat bran (WB) by alkaline treatment and was characterized by Fehling's test, dinitrosalicylic acid assay, FTIR, (1)H NMR and (13)C NMR. The synthesized nanoparticles were characterized by UV-Vis spectroscopy and transmission electron microscopy. The nanoparticles were polydispersed with the size ranging from 20 to 45 nm. The synthesized WB-xylan AgNPs showed excellent free radical scavenging activity. In addition, WB-xylan AgNPs showed fibrinolytic activity as evidenced by the zone of clearance in fibrin plate assay. The biomedical potential of the WB-xylan AgNPs was demonstrated by dissolution of preformed blood clots. These results suggest that the development of xylan-metal nanoparticle composite would be feasible to treat thrombus related diseases. PMID:26256330

  20. Size-selective chemical synthesis of tartrate stabilized cobalt ferrite ionic magnetic fluid.

    PubMed

    Neveu, S; Bee, A; Robineau, M; Talbot, D

    2002-11-15

    Ionic magnetic fluid (ferrofluid) is a stable suspension of magnetic nanoparticles in water. Cobalt ferrite nanoparticles are interesting in view of high-density recording storage. The size of the magnetic particles strongly influences the physical properties of the ferrofluids. In this study, we describe the synthesis of ionic magnetic fluid in the presence of tartrate ions. By varying the amount of organic ligands, nanoparticles in a large range of size are obtained: the mean diameter varies from 3 to 10 nm. The effect of tartrate ions on the stability of the ionic magnetic fluid is also studied in relation with the size of the magnetic particles and the amount of adsorbed ligand. PMID:12505076

  1. Synthesis and long-term phase stability of Mn3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Ristić, Mira; Musić, Svetozar; Popović, Stanko; Dragčević, Đurđica; Marciuš, Marijan; Ivanda, Mile

    2013-07-01

    The synthesis and long-term phase stability of hausmannite (Mn3O4) nanoparticles were investigated. The experimental techniques used were XRD, FT-IR, Raman, UV/Vis/NIR and FE-SEM. Mn3O4 nanoparticles were synthesized by (a) precipitation from Mn(NO3)2 and NH4OH solutions and ageing of suspensions obtained at 160 or 20 °C and (b) precipitation from MnCl2 solution with addition of H2O2 and NH4OH solutions and ageing of suspensions obtained at 90 or 20 °C. The order of adding H2O2 or NH4OH influenced the phase composition of the precipitate. A combination of XRD, Raman and FT-IR techniques was useful in investigating the long-term phase stability of Mn3O4 and changes in the nonstoichiometry of these particles. The IR bands recorded in the range 623-635 cm-1 can be assigned to the nonstoichiometry of these particles. It was shown that the IR bands at 1085, 1115 and 1150 cm-1 corresponding to OH- vibrations can be used in the interpretation of a very early stage of the phase transformation Mn3O4 → γ-MnOOH. The appearance of an IR band (shoulder) in FT-IR spectra in the range 594-599 cm-1 was discussed in terms of a possible presence of very fine γ-MnOOH particles in traces and restricted to the surface of Mn3O4 nanoparticles. The water (moisture) adsorbed on Mn3O4 particles plays a key role in the phase transformation Mn3O4 → γ-MnOOH. Other parameters related to the synthesis route also play a certain role in this phase transformation. UV/Vis spectra were briefly discussed.

  2. Green synthesis of gold nanoparticles using Stevia rebaudiana leaf extracts: Characterization and their stability.

    PubMed

    Sadeghi, Babak; Mohammadzadeh, M; Babakhani, B

    2015-07-01

    Various methods invented and developed for the synthesis of gold nanoparticles that increases daily consumed. According to this method, including potential environmental pollution problems and the complexity of the synthesis, in this study, the feasibility of using the leaves extract of Stevia rebaudiana (SR) for the reduction of gold ions to nanoparticles form have been studied. Stevia leaves were used to prepare the aqueous extract for this study. Gold nanoparticles were characterized with different techniques such as UV-vis spectroscopy, FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Transmission electron microscopy experiments showed that these nanoparticles are spherical and uniformly distributed and its size is from 5 to 20 nm. FT-IR spectroscopy revealed that gold nanoparticles were functionalized with biomolecules that have primary amine group (NH2), carbonyl group, OH groups and other stabilizing functional groups. X-ray diffraction pattern showed high purity and face centered cubic structure of gold nanoparticles with size of 17 nm. The scanning electron microscopy (SEM) implies the right of forming gold nanoparticles. The results, confirm that gold nanoparticles have synthesized by the leaves extract of S. rebaudiana (SR). PMID:25900555

  3. Coordination chemistry of cyclopropenylidene-stabilized phosphenium cations: synthesis and reactivity of Pd and Pt complexes.

    PubMed

    Kozma, Agnes; Deden, Tobias; Carreras, Javier; Wille, Christian; Petuškova, Jekaterina; Rust, Jörg; Alcarazo, Manuel

    2014-02-17

    A straightforward synthesis of cyclopropenylidene-stabilized phosphenium cations 1 a-g through the reaction of [(iPr2N)2C3(+)Cl]BF4 with secondary phosphines is described. Their donor ability was evaluated by analysis of the CO stretching frequency in Rh complexes [RhCl(CO)L2](BF4)2 and electrochemical methods. The cyclopropenium ring induces a phosphite-type behavior that can be tuned by the other two substituents attached to the phosphorus atom. Despite of the positive charge that they bear, phosphenium cations 1 a-g still act as two-electron donor ligands, forming adducts with Pd(II) and Pt(II) precursors. Conversely, in the presence of Pd(0) species, an oxidative insertion of the Pd atom into the Ccarbene-phosphorus bond takes place, providing dimeric structures in which each Pd atom is bonded to a cyclopropenyl carbene while two dialkyl/diaryl phosphide ligands serve as bridges between the two Pd centers. The catalytic performance of the resulting library of Pt(II) complexes was tested; all of the cationic phosphines accelerated the prototype 6-endo-dig cyclization of 2-ethynyl-1,1'-biphenyl to afford pentahelicene. The best ligand 1 g was used in the synthesis of two natural products, chrysotoxene and epimedoicarisoside A.

  4. Green synthesis of gold nanoparticles using Stevia rebaudiana leaf extracts: Characterization and their stability.

    PubMed

    Sadeghi, Babak; Mohammadzadeh, M; Babakhani, B

    2015-07-01

    Various methods invented and developed for the synthesis of gold nanoparticles that increases daily consumed. According to this method, including potential environmental pollution problems and the complexity of the synthesis, in this study, the feasibility of using the leaves extract of Stevia rebaudiana (SR) for the reduction of gold ions to nanoparticles form have been studied. Stevia leaves were used to prepare the aqueous extract for this study. Gold nanoparticles were characterized with different techniques such as UV-vis spectroscopy, FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Transmission electron microscopy experiments showed that these nanoparticles are spherical and uniformly distributed and its size is from 5 to 20 nm. FT-IR spectroscopy revealed that gold nanoparticles were functionalized with biomolecules that have primary amine group (NH2), carbonyl group, OH groups and other stabilizing functional groups. X-ray diffraction pattern showed high purity and face centered cubic structure of gold nanoparticles with size of 17 nm. The scanning electron microscopy (SEM) implies the right of forming gold nanoparticles. The results, confirm that gold nanoparticles have synthesized by the leaves extract of S. rebaudiana (SR).

  5. Dual template synthesis of a highly mesoporous SSZ-13 zeolite with improved stability in the methanol-to-olefins reaction.

    PubMed

    Wu, Leilei; Degirmenci, Volkan; Magusin, Pieter C M M; Szyja, Bartłomiej M; Hensen, Emiel J M

    2012-10-01

    The dual template synthesis of zeolite SSZ-13 by use of trimethyl-adamantanammonium hydroxide and a diquaternary-ammonium mesoporogen induces considerable mesoporosity without impeding zeolite microporosity. The strongly improved accessibility of Brønsted sites in mesoporous SSZ-13 increases its stability during application as an acid catalyst in the methanol-to-olefins reaction. PMID:22896837

  6. Three-dimensional benchmark for variable-density flow and transport simulation: matching semi-analytic stability modes for steady unstable convection in an inclined porous box

    USGS Publications Warehouse

    Voss, Clifford I.; Simmons, Craig T.; Robinson, Neville I.

    2010-01-01

    This benchmark for three-dimensional (3D) numerical simulators of variable-density groundwater flow and solute or energy transport consists of matching simulation results with the semi-analytical solution for the transition from one steady-state convective mode to another in a porous box. Previous experimental and analytical studies of natural convective flow in an inclined porous layer have shown that there are a variety of convective modes possible depending on system parameters, geometry and inclination. In particular, there is a well-defined transition from the helicoidal mode consisting of downslope longitudinal rolls superimposed upon an upslope unicellular roll to a mode consisting of purely an upslope unicellular roll. Three-dimensional benchmarks for variable-density simulators are currently (2009) lacking and comparison of simulation results with this transition locus provides an unambiguous means to test the ability of such simulators to represent steady-state unstable 3D variable-density physics.

  7. Synthesis, enzymatic stability and in vitro cytostatic effect of Daunorubicin-GnRH-III derivative dimers.

    PubMed

    Schreier, Verena Natalie; Mező, Gábor; Orbán, Erika; Dürr, Claudia; Marquardt, Andreas; Manea, Marilena

    2013-04-01

    Bioconjugates containing chemotherapeutic agents attached to peptide hormones, such as gonadotropin-releasing hormone (GnRH), are developed as drug delivery systems for targeted cancer chemotherapy. We report here the synthesis and biochemical characterization of disulfide bond-linked dimeric bioconjugates in which daunorubicin was coupled via an oxime linkage to aminooxyacetylated GnRH-III ([Glp-His-Trp-Ser-His-Asp-Trp-Lys(DauAoa-Cys)-Pro-Gly-NH2]2; where Glp is pyroglutamic acid and Aoa is aminooxyacetyl) and its derivatives modified in position four by N-Me-Ser and Lys(Ac). The in vitro stability/degradation of the bioconjugates was determined in human serum, as well as in the presence of rat liver lysosomal homogenate and digestive enzymes. All compounds were stable at least for 24h in human serum and in the presence of pepsin and trypsin, while they were degraded by lysosomal enzymes. The daunorubicin-GnRH-III derivative dimers were partly digested by α-chymotrypsin; however, they had increased stability compared to the corresponding monomers, making them potential candidates for oral administration. The in vitro cytostatic effect of the compounds was determined on MCF-7 human breast cancer cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. All daunorubicin-GnRH-III derivative dimers exerted slightly increased in vitro cytostatic effect (IC50 values in low μM range) than the corresponding monomeric bioconjugates.

  8. Effect of Nitric Acid Concentrations on Synthesis and Stability of Maghemite Nanoparticles Suspension

    PubMed Central

    Yaacob, Iskandar Idris

    2014-01-01

    Maghemite (γ-Fe2O3) nanoparticles have been synthesized using a chemical coprecipitation method at different nitric acid concentrations as an oxidizing agent. Characterization of all samples performed by several techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), alternating gradient magnetometry (AGM), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and zeta potential. The XRD patterns confirmed that the particles were maghemite. The crystallite size of all samples decreases with the increasing concentration of nitric acid. TEM observation showed that the particles have spherical morphology with narrow particle size distribution. The particles showed superparamagnetic behavior with decreased magnetization values at the increasing concentration of nitric acid. TGA measurement showed that the stability temperature decreases with the increasing concentration of nitric acid. DLS measurement showed that the hydrodynamic particle sizes decrease with the increasing concentration of nitric acid. Zeta potential values show a decrease with the increasing concentration of nitric acid. The increasing concentration of nitric acid in synthesis of maghemite nanoparticles produced smaller size particles, lower magnetization, better thermal stability, and more stable maghemite nanoparticles suspension. PMID:24963510

  9. Comment on `Stability analysis and controller synthesis for discrete linear time-delay systems with state saturation nonlinearities'

    NASA Astrophysics Data System (ADS)

    Tadepalli, Siva Kumar; Krishna Rao Kandanvli, V.; Kar, Haranath

    2015-11-01

    A recently reported paper (Ji, X., Liu, T., Sun, Y., and Su, H. (2011), 'Stability analysis and controller synthesis for discrete linear time-delay systems with state saturation nonlinearities', International Journal of Systems Science, 42, 397-406) for the global asymptotic stability analysis and controller synthesis for a class of discrete linear time delay systems employing state saturation nonlinearities is reviewed. It is claimed in Ji, Liu, Sun and Su (2011) that a previous approach by Kandanvli and Kar (Kandanvli, V.K.R and Kar, H. (2009), 'Robust stability of discrete-time state-delayed systems with saturation nonlinearities: Linear matrix inequality approach', Signal Processing, 89, 161-173) is recovered from their approach as a special case. It is shown that this claim is not justified.

  10. Science Prop Boxes

    ERIC Educational Resources Information Center

    Hommerding, Molly

    2007-01-01

    A prop box is a teacher-created resource full of age-appropriate and meaningful activities focused on a central theme. Prop boxes work much like learning centers in an elementary classroom with the important addition of providing opportunities for socio-dramatic play. Prop box play engages students in self-chosen activities that promote critical…

  11. A System for Cooling inside a Glove Box

    ERIC Educational Resources Information Center

    Sanz, Martial

    2010-01-01

    An easy, efficient, reliable, and low-cost method of constructing a cooling system using a simple circulating pump is described. The system is employed in conjunction with an inert atmosphere glove box to achieve the synthesis of air- and moisture-sensitive compounds inside the glove box at controlled, low temperatures without contaminating the…

  12. Green Synthesis of AgNPs Stabilized with biowaste and their antimicrobial activities

    PubMed Central

    Jasuja, Nakuleshwar Dut; Gupta, Deepak Kumar; Reza, Mohtashim; Joshi, Suresh C.

    2014-01-01

    In the present study, rapid reduction and stabilization of Ag+ ions with different NaOH molar concentration (0.5 mM, 1.0 mM and 1.5 mM) has been carried out in the aqueous solution of silver nitrate by the bio waste peel extract of P.granatum. Generally, chemical methods used for the synthesis of AgNPs are quite toxic, flammable and have adverse effect in medical application but green synthesis is a better option due to eco-friendliness, non-toxicity and safe for human. Stable AgNPs were synthesized by treating 90 mL aqueous solution of 2 mM AgNO3 with the 5 mL plant peels extract (0.4% w/v) at different NaOH concentration (5 mL). The synthesized AgNPs were characterized by UV-Vis spectroscopy, TEM and SEM. Further, antimicrobial activities of AgNPs were performed on Gram positive i.e. Staphylococcus aureus, Bacillus subtilius and Gram negative i.e. E. coli, Pseudomonas aeruginosa bacteria. The AgNPs synthesized at 1.5 mM NaOH concentration had shown maximum zone of inhibition (ZOI) i.e. 49 ± 0.64 in E. coli, whereas Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilius had shown 40 ± 0.29 mm, 28 ± 0.13 and 42 ± 0.49 mm ZOI respectively. The MIC value of 30 μg/mL observed for E. coli Whereas, Staphylococcus aureus, Bacillus subtilius and Pseudomonas aeruginosa had shown 45 μg/mL, 38 μg/mL, 35 μg/mL respectively. The study revealed that AgNPs had shown significant antimicrobial activity as compared to Streptomycin. PMID:25763037

  13. Hydroxypropylcellulose as a novel green reservoir for the synthesis, stabilization, and storage of silver nanoparticles.

    PubMed

    Hussain, Muhammad Ajaz; Shah, Abdullah; Jantan, Ibrahim; Shah, Muhammad Raza; Tahir, Muhammad Nawaz; Ahmad, Riaz; Bukhari, Syed Nasir Abbas

    2015-01-01

    Polysaccharides are attracting the vigil eye of researchers in order to design the green synthesis of silver nanoparticles (Ag NPs) of diverse size, shape, and application. We report an environmentally friendly method to synthesize Ag NPs where no physical reaction conditions were employed. Hydroxypropylcellulose (HPC) was used as a template nanoreactor, stabilizer, and capping agent to obtain Ag NPs. Different concentrations of AgNO3 solutions (50 mmol, 75 mmol, and 100 mmol) were mixed with a concentrated aqueous solution of HPC and the progress of the reaction was monitored by noting color changes of the reaction mixture at different reaction times for up to 24 hours. Characteristic ultraviolet-visible spectroscopy (UV/Vis) absorption bands of Ag NPs were observed in the range of 388-452 nm. The morphology of the Ag NPs was studied by scanning electron microscopy, transmission electron microscopy (TEM), and atomic force microscopy. The TEM images confirmed that the size of the Ag NPs was in the range of 25-55 nm. Powder X-ray diffraction studies showed that the crystal phase of the Ag NPs was face-centered cubic. The as-prepared Ag NPs were found to be stable, and no changes in size and morphology were observed after storage in HPC thin films over 1 year, as indicated by UV/Vis spectra. So, the present work furnishes a green and economical strategy for the synthesis and storage of stable Ag NPs. As-synthesized Ag NPs showed significant antimicrobial activity against different bacterial (Escherichia coli, Staphylococcus epidermidis, S. aureus, Bacillus subtilis, Pseudomonas aeruginosa) and fungal strains (Actinomycetes and Aspergillus niger).

  14. Hydroxypropylcellulose as a novel green reservoir for the synthesis, stabilization, and storage of silver nanoparticles

    PubMed Central

    Hussain, Muhammad Ajaz; Shah, Abdullah; Jantan, Ibrahim; Shah, Muhammad Raza; Tahir, Muhammad Nawaz; Ahmad, Riaz; Bukhari, Syed Nasir Abbas

    2015-01-01

    Polysaccharides are attracting the vigil eye of researchers in order to design the green synthesis of silver nanoparticles (Ag NPs) of diverse size, shape, and application. We report an environmentally friendly method to synthesize Ag NPs where no physical reaction conditions were employed. Hydroxypropylcellulose (HPC) was used as a template nanoreactor, stabilizer, and capping agent to obtain Ag NPs. Different concentrations of AgNO3 solutions (50 mmol, 75 mmol, and 100 mmol) were mixed with a concentrated aqueous solution of HPC and the progress of the reaction was monitored by noting color changes of the reaction mixture at different reaction times for up to 24 hours. Characteristic ultraviolet–visible spectroscopy (UV/Vis) absorption bands of Ag NPs were observed in the range of 388–452 nm. The morphology of the Ag NPs was studied by scanning electron microscopy, transmission electron microscopy (TEM), and atomic force microscopy. The TEM images confirmed that the size of the Ag NPs was in the range of 25–55 nm. Powder X-ray diffraction studies showed that the crystal phase of the Ag NPs was face-centered cubic. The as-prepared Ag NPs were found to be stable, and no changes in size and morphology were observed after storage in HPC thin films over 1 year, as indicated by UV/Vis spectra. So, the present work furnishes a green and economical strategy for the synthesis and storage of stable Ag NPs. As-synthesized Ag NPs showed significant antimicrobial activity against different bacterial (Escherichia coli, Staphylococcus epidermidis, S. aureus, Bacillus subtilis, Pseudomonas aeruginosa) and fungal strains (Actinomycetes and Aspergillus niger). PMID:25844038

  15. Ultrasound-assisted butyl acetate synthesis catalyzed by Novozym 435: enhanced activity and operational stability.

    PubMed

    Martins, Andréa B; Schein, Mirela F; Friedrich, John L R; Fernandez-Lafuente, Roberto; Ayub, Marco A Z; Rodrigues, Rafael C

    2013-09-01

    The influence of low-frequency ultrasound (40 kHz) in the esterification reaction between acetic acid and butanol for flavor ester synthesis catalyzed by the commercial immobilized lipase B from Candida antarctica (Novozym 435) was evaluated. A central composite design and the response surface methodology were used to analyze the effects of the reaction parameters (temperature, substrate molar ratio, enzyme content and added water) and their response (yields of conversion in 2.5 h of reaction). The reaction was carried out using n-hexane as solvent. The optimal conditions for ultrasound-assisted butyl acetate synthesis were found to be: temperature of 46 °C; substrate molar ratio of 3.6:1 butanol:acetic acid; enzyme content of 7%; added water of 0.25%, conditions that are slightly different from those found using mechanical mixing. Over 94% of conversion was obtained in 2.5h under these conditions. The optimal acid concentration for the reaction was determined to be 2.0 M, compared to 0.3 M without ultrasound treatment. Enzyme productivity was significantly improved to around 7.5-fold for each batch when comparing ultrasound and standard mechanical agitation. The biocatalyst could be directly reused for 14 reactions cycles keeping around 70% of its original activity, while activity was virtually zeroed in the third cycle using the standard mixing system. Thus, compared to the traditional mechanical agitation, ultrasound technology not only improves the process productivity, but also enhances enzyme recycling and stability in the presence of acetic acid, being a powerful tool to improve biocatalyst performance in this type of reaction. PMID:23453821

  16. Green Synthesis of AgNPs Stabilized with biowaste and their antimicrobial activities.

    PubMed

    Jasuja, Nakuleshwar Dut; Gupta, Deepak Kumar; Reza, Mohtashim; Joshi, Suresh C

    2014-01-01

    In the present study, rapid reduction and stabilization of Ag+ ions with different NaOH molar concentration (0.5 mM, 1.0 mM and 1.5 mM) has been carried out in the aqueous solution of silver nitrate by the bio waste peel extract of P.granatum. Generally, chemical methods used for the synthesis of AgNPs are quite toxic, flammable and have adverse effect in medical application but green synthesis is a better option due to eco-friendliness, non-toxicity and safe for human. Stable AgNPs were synthesized by treating 90 mL aqueous solution of 2 mM AgNO₃ with the 5 mL plant peels extract (0.4% w/v) at different NaOH concentration (5 mL). The synthesized AgNPs were characterized by UV-Vis spectroscopy, TEM and SEM. Further, antimicrobial activities of AgNPs were performed on Gram positive i.e. Staphylococcus aureus, Bacillus subtilius and Gram negative i.e. E. coli, Pseudomonas aeruginosa bacteria. The AgNPs synthesized at 1.5 mM NaOH concentration had shown maximum zone of inhibition (ZOI) i.e. 49 ± 0.64 in E. coli, whereas Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilius had shown 40 ± 0.29 mm, 28 ± 0.13 and 42 ± 0.49 mm ZOI respectively. The MIC value of 30 μg/mL observed for E. coli Whereas, Staphylococcus aureus, Bacillus subtilius and Pseudomonas aeruginosa had shown 45 μg/mL, 38 μg/mL, 35 μg/mL respectively. The study revealed that AgNPs had shown significant antimicrobial activity as compared to Streptomycin.

  17. Hydroxypropylcellulose as a novel green reservoir for the synthesis, stabilization, and storage of silver nanoparticles.

    PubMed

    Hussain, Muhammad Ajaz; Shah, Abdullah; Jantan, Ibrahim; Shah, Muhammad Raza; Tahir, Muhammad Nawaz; Ahmad, Riaz; Bukhari, Syed Nasir Abbas

    2015-01-01

    Polysaccharides are attracting the vigil eye of researchers in order to design the green synthesis of silver nanoparticles (Ag NPs) of diverse size, shape, and application. We report an environmentally friendly method to synthesize Ag NPs where no physical reaction conditions were employed. Hydroxypropylcellulose (HPC) was used as a template nanoreactor, stabilizer, and capping agent to obtain Ag NPs. Different concentrations of AgNO3 solutions (50 mmol, 75 mmol, and 100 mmol) were mixed with a concentrated aqueous solution of HPC and the progress of the reaction was monitored by noting color changes of the reaction mixture at different reaction times for up to 24 hours. Characteristic ultraviolet-visible spectroscopy (UV/Vis) absorption bands of Ag NPs were observed in the range of 388-452 nm. The morphology of the Ag NPs was studied by scanning electron microscopy, transmission electron microscopy (TEM), and atomic force microscopy. The TEM images confirmed that the size of the Ag NPs was in the range of 25-55 nm. Powder X-ray diffraction studies showed that the crystal phase of the Ag NPs was face-centered cubic. The as-prepared Ag NPs were found to be stable, and no changes in size and morphology were observed after storage in HPC thin films over 1 year, as indicated by UV/Vis spectra. So, the present work furnishes a green and economical strategy for the synthesis and storage of stable Ag NPs. As-synthesized Ag NPs showed significant antimicrobial activity against different bacterial (Escherichia coli, Staphylococcus epidermidis, S. aureus, Bacillus subtilis, Pseudomonas aeruginosa) and fungal strains (Actinomycetes and Aspergillus niger). PMID:25844038

  18. Taking Stress Response out of the Box: Stability, Discontinuity, and Temperament Effects on HPA and SNS across Social Stressors in Mother-Infant Dyads

    ERIC Educational Resources Information Center

    Laurent, Heidemarie K.; Ablow, Jennifer C.; Measelle, Jeffrey

    2012-01-01

    This study investigated continuity and stability of hypothalamic-pituitary-adrenal (HPA) and sympathetic nervous system (SNS) response measures in mother-infant dyads across 2 different types of social stress sessions. Synchrony of response trajectories across systems (SNS-HPA coordination) and partners (mother-infant attunement) was addressed, as…

  19. Multivariate optimization of process parameters in the synthesis of calcined Ca‒Al (NO3) LDH for defluoridation using 3(3) factorial, central composite and Box-Behnken design.

    PubMed

    Ghosal, Partha S; Gupta, Ashok K; Sulaiman, Ayoob

    2016-01-01

    Response surface methodology was applied for the first time in the optimization of the preparation of layered double hydroxide (LDH) for defluoridation. The influence of three vital process parameters (viz. pH, molar ratio and calcination temperature) in the synthesis of the adsorbent 'Calcined Ca‒Al (NO3) LDH' was thoroughly examined to maximize its fluoride scavenging potential. The process parameters were optimized using the 3(3) factorial, face centered central composite and Box-Behnken designs and a comparative assessment of the methods was conducted. The maximum fluoride removal efficiency was achieved at a calcination temperature of approximately 500ºC; however, the efficiency decreased with increasing pH and molar ratio. The outcome of the comparative assessment clearly delineates the case specific nature of the models. A better predictability over the entire experimental domain was obtained with the 3(3) factorial method, whereas the Box-Behnken design was found to be the most efficient model with lesser number of experimental runs. The desirability function technique was performed for optimizing the response, wherein face centered central composite design exhibited a maximum desirability. The calcined Ca‒Al (NO3) LDH, synthesized under the optimum conditions, demonstrated the removal efficiencies of 95% and 99% for the doses of 3 g L(-1) and 5 g L(-1), respectively.

  20. Multivariate optimization of process parameters in the synthesis of calcined Ca‒Al (NO3) LDH for defluoridation using 3(3) factorial, central composite and Box-Behnken design.

    PubMed

    Ghosal, Partha S; Gupta, Ashok K; Sulaiman, Ayoob

    2016-01-01

    Response surface methodology was applied for the first time in the optimization of the preparation of layered double hydroxide (LDH) for defluoridation. The influence of three vital process parameters (viz. pH, molar ratio and calcination temperature) in the synthesis of the adsorbent 'Calcined Ca‒Al (NO3) LDH' was thoroughly examined to maximize its fluoride scavenging potential. The process parameters were optimized using the 3(3) factorial, face centered central composite and Box-Behnken designs and a comparative assessment of the methods was conducted. The maximum fluoride removal efficiency was achieved at a calcination temperature of approximately 500ºC; however, the efficiency decreased with increasing pH and molar ratio. The outcome of the comparative assessment clearly delineates the case specific nature of the models. A better predictability over the entire experimental domain was obtained with the 3(3) factorial method, whereas the Box-Behnken design was found to be the most efficient model with lesser number of experimental runs. The desirability function technique was performed for optimizing the response, wherein face centered central composite design exhibited a maximum desirability. The calcined Ca‒Al (NO3) LDH, synthesized under the optimum conditions, demonstrated the removal efficiencies of 95% and 99% for the doses of 3 g L(-1) and 5 g L(-1), respectively. PMID:26549036

  1. Synthesis of superhydrophobic silica nanofibrous membranes with robust thermal stability and flexibility via in situ polymerization

    NASA Astrophysics Data System (ADS)

    Yang, Liping; Raza, Aikifa; Si, Yang; Mao, Xue; Shang, Yanwei; Ding, Bin; Yu, Jianyong; Al-Deyab, Salem S.

    2012-09-01

    adsorption method has confirmed the correlation between hierarchical roughness and WCA for the modified membranes. Furthermore, the as-prepared membranes exhibited high thermal stability (450 °C), good flexibility (0.0127 gf cm), and comparable tensile strength (2.58 MPa), suggesting their use as promising materials for a variety of potential applications in high-temperature filtration, self-cleaning coatings, catalyst carriers, etc., and also provided new insight into the design and development of functional nanofibrous membranes through F-PBZ modification. Electronic supplementary information (ESI) available: Detailed chemical synthesis and structural confirmation of BAF-tfa, FT-IR results, and FE-SEM results. See DOI: 10.1039/c2nr32095a

  2. Synthesis and biological assessment of simplified analogues of the potent microtubule stabilizer (+)-discodermolide.

    PubMed

    Mínguez, José M; Kim, Sun-Young; Giuliano, Kenneth A; Balachandran, Raghavan; Madiraju, Charitha; Day, Billy W; Curran, Dennis P

    2003-07-31

    An efficient, convergent and stereocontrolled synthesis of simplified analogues of the potent antimitotic agent (+)-discodermolide has been achieved and several small libraries have been prepared. In all the libraries, the discodermolide methyl groups at C14 and C16 and the C7 hydroxy group were removed and the lactone was replaced by simple esters. Other modifications introduced in each series of analogues were related to C11, C17 and C19 of the natural product. Key elements of the synthetic strategy included (a) elaboration of the main subunits from a common intermediate and (b) fragment couplings using Wittig reactions to install the (Z)-olefins. Library components were analyzed for microtubule-stabilizing actions in vitro, for displacement of [3H]paclitaxel from its binding site on tubulin, for antiproliferative activity against human carcinoma cells, and for cell signaling and mitotic spindle alterations by a multiparameter fluorescence cell-based screening technique. The results show that even significant structural simplification can lead to analogues with actions related to microtubule targeting.

  3. Synthesis and characterization of supported polysugar-stabilized palladium nanoparticle catalysts for enhanced hydrodechlorination of trichloroethylene.

    PubMed

    Bacik, Deborah B; Zhang, Man; Zhao, Dongye; Roberts, Christopher B; Seehra, Mohinar S; Singh, Vivek; Shah, Naresh

    2012-07-27

    Palladium (Pd) nanoparticle catalysts were successfully synthesized within an aqueous phase using sodium carboxymethyl cellulose (CMC) as a capping ligand which offers a green alternative to conventional nanoparticle synthesis techniques. The CMC-stabilized Pd nanoparticles were subsequently dispersed within support materials using the incipient wetness impregnation technique for utilization in heterogeneous catalyst systems. The unsupported and supported (both calcined and uncalcined) Pd nanoparticle catalysts were characterized using transmission electron microscopy, energy dispersive x-ray spectrometry, x-ray diffraction, and Brunauer-Emmett-Teller surface area measurement and their catalytic activity toward the hydrodechlorination of trichloroethylene (TCE) in aqueous media was examined using homogeneous and heterogeneous catalyst systems, respectively. The unsupported Pd nanoparticles showed considerable activity toward the degradation of TCE, as demonstrated by the reaction kinetics. Although the supported Pd nanoparticle catalysts had a lower catalytic activity than the unsupported particles that were homogeneously dispersed in the aqueous solutions, the supported catalysts retained sufficient activity toward the degradation of TCE. In addition, the use of the hydrophilic Al(2)O(3) support material induced a mass transfer resistance to TCE that affected the initial hydrodechlorination rate. This paper demonstrates that supported Pd catalysts can be applied to the heterogeneous catalytic hydrodechlorination of TCE. PMID:22743584

  4. Synthesis and characterization of supported polysugar-stabilized palladium nanoparticle catalysts for enhanced hydrodechlorination of trichloroethylene

    NASA Astrophysics Data System (ADS)

    Bacik, Deborah B.; Zhang, Man; Zhao, Dongye; Roberts, Christopher B.; Seehra, Mohinar S.; Singh, Vivek; Shah, Naresh

    2012-07-01

    Palladium (Pd) nanoparticle catalysts were successfully synthesized within an aqueous phase using sodium carboxymethyl cellulose (CMC) as a capping ligand which offers a green alternative to conventional nanoparticle synthesis techniques. The CMC-stabilized Pd nanoparticles were subsequently dispersed within support materials using the incipient wetness impregnation technique for utilization in heterogeneous catalyst systems. The unsupported and supported (both calcined and uncalcined) Pd nanoparticle catalysts were characterized using transmission electron microscopy, energy dispersive x-ray spectrometry, x-ray diffraction, and Brunauer-Emmett-Teller surface area measurement and their catalytic activity toward the hydrodechlorination of trichloroethylene (TCE) in aqueous media was examined using homogeneous and heterogeneous catalyst systems, respectively. The unsupported Pd nanoparticles showed considerable activity toward the degradation of TCE, as demonstrated by the reaction kinetics. Although the supported Pd nanoparticle catalysts had a lower catalytic activity than the unsupported particles that were homogeneously dispersed in the aqueous solutions, the supported catalysts retained sufficient activity toward the degradation of TCE. In addition, the use of the hydrophilic Al2O3 support material induced a mass transfer resistance to TCE that affected the initial hydrodechlorination rate. This paper demonstrates that supported Pd catalysts can be applied to the heterogeneous catalytic hydrodechlorination of TCE.

  5. Defective synthesis of lipid intermediates for peptidoglycan formation in a stabilized L-form of Streptococcus pyogenes.

    PubMed Central

    Reusch, V M; Panos, C

    1976-01-01

    Membrane preparations obtained from a stabilized L-form of Streptococcus pyogenes are incapable of synthesizing peptidoglycan from uridine-5'-diphospho-N-acetyl-D-muramyl-L-Ala-D-iso-Glu-L-Lys-D-Ala-D-Ala and uridine-5'-diphospho-N-acetyl-D-glucosamine, in contrast with similar preparations from the parental streptococcus. Furthermore, 50-fold higher levels of lipid intermediates which serve as membrane-bound substrates for peptidoglycan synthesis are synthesized in reaction mixtures containing streptococcal membranes than with similar preparations from the L-form. These observations suggest that the inability of this stabilized L-form to form a cell wall in vivo lies, at least in part, in its failure to synthesize significant quantities of the lipid substrates for peptidoglycan synthesis. PMID:4426

  6. Synthesis, characterization and stability of Cr(III) and Fe(III) hydroxides.

    PubMed

    Papassiopi, N; Vaxevanidou, K; Christou, C; Karagianni, E; Antipas, G S E

    2014-01-15

    Chromium is a common contaminant of soils and aquifers and constitutes a major environmental problem. In nature, chromium usually exists in the form of two oxidation states, trivalent, Cr(III), which is relatively innocuous for biota and for the aquatic environment, and hexavalent, Cr(VI) which is toxic, carcinogenic and very soluble. Accordingly, the majority of wastewater and groundwater treatment technologies, include a stage where Cr(VI) is reduced to Cr(III), in order to remove chromium from the aqueous phase and bind the element in the form of environmentally stable solid compounds. In the absence of iron the final product is typically of the form Cr(OH)3·xH2O whereas in the presence of iron the precipitate is a mixed Fe(1-x)Crx(OH)3 phase. In this study, we report on the synthesis, characterisation and stability of mixed (Fex,Cr1-x)(OH)3 hydroxides as compared to the stability of Cr(OH)3. We established that the plain Cr(III) hydroxide, abiding to the approximate molecular formula Cr(OH)3·3H2O, was crystalline, highly soluble, i.e. unstable, with a tendency to transform into the stable amorphous hydroxide Cr(OH)3(am) phase. Mixed Fe0.75Cr0.25(OH)3 hydroxides were found to be of the ferrihydrite structure, Fe(OH)3, and we correlated their solubility to that of a solid solution formed by plain ferrihydrite and the amorphous Cr(III) hydroxide. Both our experimental results and thermodynamic calculations indicated that mixed Fe(III)-Cr(III) hydroxides are more effective enhancers of groundwater quality, in comparison to the plain amorphous or crystalline Cr(III) hydroxides, the latter found to have a solubility typically higher than 50μg/l (maximum EU permitted Cr level in drinking water), while the amorphous Cr(OH)3(am) phase was within the drinking water threshold in the range 5.7stability in the 4.8

  7. An Improved Box Theater

    NASA Astrophysics Data System (ADS)

    Huster, Michael E.

    2011-09-01

    While designing an optics lab for a conceptual physics course, I came across a "box theater" activity. The box theater is a pinhole camera obscura made from a box that students put over their heads and shoulders. I use the activity as a capstone experience to explain optical systems. (Classroom demonstrations of the camera obscura have been described by others.2) First, the students build and experiment with a camera obscura made from a plastic cup and a convex lens with a focal length of 7.5 cm, and then "wear" the box theater. The difficulty with the box theater is the dimness of the image. A cloth drape has to be hung from the bottom of the box around the shoulders of the students to prevent light leakage, and the students have to wait a few minutes for their eyes to adjust to the darkness.

  8. Expanding the synthesis of new trans-sulfonamide platinum complexes: cytotoxicity, SAR, fluorescent cell assays and stability studies.

    PubMed

    Del Solar, Virginia; Quiñones-Lombraña, Adolfo; Cabrera, Silvia; Padrón, José M; Ríos-Luci, Carla; Alvarez-Valdés, Amparo; Navarro-Ranninger, Carmen; Alemán, José

    2013-10-01

    In this manuscript, we describe the synthesis of new trans-N-sulfonamide platinum complexes and their antiproliferative activity (GI50, μM) in human solid tumors cells. The structure activity relationships (SAR), with different new synthesized complexes by variation in ligand, halogen and also in the stereochemistry of the ligand, has been studied. Solubility and stability studies have also been carried out as well as fluorescent cell assays in order to clarify the final target in the tumor cells. PMID:23474039

  9. GLOVE BOX ATTACHMENT

    DOEpatents

    Butts, H.L.

    1962-02-13

    This invention comprises a housing unit to be fitted between a glove box port and a glove so that a slidable plate within the housing seals off the glove box port for evacuation of the glove box without damage to the glove. The housing and the glove may be evacuated without damage to the glove since movement of the glove is restricted during evacuation by the slidable plate. (AEC)

  10. Coating with mesoporous silica remarkably enhances the stability of the highly active yet fragile flower-like MgO catalyst for dimethyl carbonate synthesis.

    PubMed

    Cui, Zhi-Min; Chen, Zhe; Cao, Chang-Yan; Song, Wei-Guo; Jiang, Lei

    2013-07-11

    Flower-like MgO is a highly effective catalyst for the synthesis of dimethyl carbonate through the transesterification method, and coating the catalyst with mesoporous silica significantly enhances the stability of the MgO catalyst.

  11. Discovery of hypoiodite-mediated aminyl radical cyclization lacking a nitrogen radical-stabilizing group: application to synthesis of an oxazaspiroketal-containing cephalostatin analog.

    PubMed

    Koag, Myong; Lee, Seongmin

    2011-09-16

    Synthesis of an oxazaspiroketal-containing bissteroidal pyrazine is described. The key transformation of this synthesis involves stereoselective formation of oxazaspiroketal via aminyl-radical cyclization of primary amine lacking a radical-stabilizing group by Suárez hypoiodite oxidation.

  12. The mirror box

    NASA Astrophysics Data System (ADS)

    Thompson, Gene; Mathieson, Don

    2001-11-01

    The mirror box is an old standby in magic shows and an impressive demonstration of the law of reflection for the physics instructor. The box creates the illusion of an object floating in space by the use of a plane mirror.

  13. Thinking outside the Box

    ERIC Educational Resources Information Center

    Fanshawe, Simon; Sriskandarajah, Dhananjayan

    2010-01-01

    Britain is not only more diverse than ever before, but that diversity itself is growing more diverse. Britain's simplistic "tick-box" approach to identity is in danger of inhibiting the very equality it seeks to promote. To question the tick-box is not to accuse local authorities of "political correctness gone mad". The notion of political…

  14. Environmental Exchange Box

    ERIC Educational Resources Information Center

    Moseley, Christine

    2003-01-01

    In this activity, teachers in one state create and share an "exchange box" of environmental and cultural items with students of another state. The Environmental Exchange Box activity enables teachers to improve students' skills in scientific inquiry and develop attitudes and values conducive to science learning such as wonder, curiosity, and…

  15. Math in the Box

    ERIC Educational Resources Information Center

    DeYoung, Mary J.

    2009-01-01

    This article describes how to make an origami paper box and explores the algebra, geometry, and other mathematics that unfolds. A set of origami steps that transforms the paper into an open box can hold mathematical surprises for both students and teachers. An origami lesson can engage students in an open-ended exploration of the relationship…

  16. Unusual aerobic stabilization of Cob(I)alamin by a B12-trafficking protein allows chemoenzymatic synthesis of organocobalamins.

    PubMed

    Li, Zhu; Lesniak, Nicholas A; Banerjee, Ruma

    2014-11-19

    CblC, a B12 trafficking protein, exhibits glutathione transferase and reductive decyanase activities for processing alkylcobalamins and cyanocobalamin, respectively, to a common intermediate that is subsequently converted to the biologically active forms of the cofactor. We recently discovered that the Caenorhabditis elegans CblC catalyzes thiol-dependent decyanation of CNCbl and reduction of OH2Cbl and stabilizes the paramagnetic cob(II)alamin product under aerobic conditions. In this study, we report the striking ability of the worm CblC to stabilize the highly reactive cob(I)alamin product of the glutathione transferase reaction. The unprecedented stabilization of the supernucleophilic cob(I)alamin species under aerobic conditions by the intrinsic thiol oxidase activity of CblC, was exploited for the chemoenzymatic synthesis of organocobalamin derivatives under mild conditions.

  17. Di- and tri-cobalt silicotungstates: synthesis, characterization, and stability studies.

    PubMed

    Zhu, Guibo; Geletii, Yurii V; Song, Jie; Zhao, Chongchao; Glass, Elliot N; Bacsa, John; Hill, Craig L

    2013-01-18

    Di- and tricobalt silicotungstate complexes, K(5)Na(4)H(4)[{Na(3)(μ-OH(2))(2)Co(2)(μ-OH)(4)} (Si(2)W(18)O(66))]·37H(2)O (1) and K(6)Na(3)[Na(H(2)O){Co(H(2)O)(3)}(2){Co(H(2)O)(2)}(Si(2)W(18)O(66))]·22H(2)O (2), have been synthesized through reaction of cobalt chloride and [A-α-SiW(9)O(34)](10-) in acidic buffer solution. They have been characterized by X-ray crystallography, elemental analysis, cyclic voltammetry, infrared, and UV-vis spectroscopy. In 1, two cobalt atoms as well as three sodium atoms are incorporated in the central pocket of the [Si(2)W(18)O(66)](16-) polyanion. In 2, one cobalt atom and one sodium atom are incorporated in the pocket of [Si(2)W(18)O(66)](16-); two other cobalt atoms in this complex protrude outside the pocket and connect with WO(6) units of other [Si(2)W(18)O(66)](16-) polyanions to form a one-dimensional polymeric structure. The crucial parameters in the synthesis of these two compounds are discussed, and their stability in different buffer solutions is studied. The decomposition of 1 or 2 in heated potassium acetate buffer (pH 4.8, 1 M) yields K(11)[{Co(2)(H(2)O)(8)}K(Si(2)W(18)O(66))]·17H(2)O (3) based on spectroscopic studies and an X-ray crystal structure.

  18. The Controller Synthesis of Metastable Oxides Utilizing Epitaxy and Epitaxial Stabilization

    SciTech Connect

    Schlom, Darrell

    2003-12-02

    Molecular beam epitaxy (MBE) has achieved unparalleled control in the integration of semiconductors at the nanometer. These advances were made through the use of epitaxy, epitaxial stabilization, and a combination of composition-control techniques including adsorption-controlled growth and RHEED-based composition control that we have developed, understood, and utilized for the growth of oxides. Also key was extensive characterization (utilizing RHEED, four-circle x-ray diffraction, AFM, TEM, and electrical characterization techniques) in order to study growth modes, optimize growth conditions, and probe the structural, dielectric, and ferroelectric properties of the materials grown. The materials that we have successfully engineered include titanates (PbTiO3, Bi4Ti3O12), tantalates (SrBi2Ta2O9), and niobates (SrBi2Nb2O9); layered combinations of these perovskite-related materials (Bi4Ti3O12-SrTiO3 and Bi4Ti3O12-PbTiO3 Aurivillius phases and metastable PbTiO3/SrTiO3 and BaTiO3/SrTiO3 superlattices), and new metastable phases (Srn+1TinO3n+1 Ruddlesden-Popper phases). The films were grown by reactive MBE and pulsed laser deposition (PLD). Many of these materials are either new or have been synthesized with the highest perfection ever reported. The controlled synthesis of such layered oxide heterostructures offers great potential for tailoring the superconducting, ferroelectric, and dielectric properties of these materials. These properties are important for energy technologies.

  19. Recent Advances in the Synthesis and Stabilization of Nickel and Nickel Oxide Nanoparticles: A Green Adeptness

    PubMed Central

    Rani, Aneela

    2016-01-01

    Green protocols for the synthesis of nanoparticles have been attracting a lot of attention because they are eco-friendly, rapid, and cost-effective. Nickel and nickel oxide nanoparticles have been synthesized by green routes and characterized for impact of green chemistry on the properties and biological effects of nanoparticles in the last five years. Green synthesis, properties, and applications of nickel and nickel oxide nanoparticles have been reported in the literature. This review summarizes the synthesis of nickel and nickel oxide nanoparticles using different biological systems. This review also provides comparative overview of influence of chemical synthesis and green synthesis on structural properties of nickel and nickel oxide nanoparticles and their biological behavior. It concludes that green methods for synthesis of nickel and nickel oxide nanoparticles are better than chemical synthetic methods. PMID:27413375

  20. Recent Advances in the Synthesis and Stabilization of Nickel and Nickel Oxide Nanoparticles: A Green Adeptness.

    PubMed

    Imran Din, Muhammad; Rani, Aneela

    2016-01-01

    Green protocols for the synthesis of nanoparticles have been attracting a lot of attention because they are eco-friendly, rapid, and cost-effective. Nickel and nickel oxide nanoparticles have been synthesized by green routes and characterized for impact of green chemistry on the properties and biological effects of nanoparticles in the last five years. Green synthesis, properties, and applications of nickel and nickel oxide nanoparticles have been reported in the literature. This review summarizes the synthesis of nickel and nickel oxide nanoparticles using different biological systems. This review also provides comparative overview of influence of chemical synthesis and green synthesis on structural properties of nickel and nickel oxide nanoparticles and their biological behavior. It concludes that green methods for synthesis of nickel and nickel oxide nanoparticles are better than chemical synthetic methods. PMID:27413375

  1. Repression of ergosterol level during oxidative stress by fission yeast F-box protein Pof14 independently of SCF

    PubMed Central

    Tafforeau, Lionel; Le Blastier, Sophie; Bamps, Sophie; Dewez, Monique; Vandenhaute, Jean; Hermand, Damien

    2006-01-01

    We describe a new member of the F-box family, Pof14, which forms a canonical, F-box dependent SCF (Skp1, Cullin, F-box protein) ubiquitin ligase complex. The Pof14 protein has intrinsic instability that is abolished by inactivation of its Skp1 interaction motif (the F-box), Skp1 or the proteasome, indicating that Pof14 stability is controlled by an autocatalytic mechanism. Pof14 interacts with the squalene synthase Erg9, a key enzyme in ergosterol metabolism, in a membrane-bound complex that does not contain the core SCF components. pof14 transcription is induced by hydrogen peroxide and requires the Pap1 transcription factor and the Sty1 MAP kinase. Pof14 binds to and decreases Erg9 activity in vitro and a pof14 deletion strain quickly loses viability in the presence of hydrogen peroxide due to its inability to repress ergosterol synthesis. A pof14 mutant lacking the F-box and an skp1-3 ts mutant behave as wild type in the presence of oxidant showing that Pof14 function is independent of SCF. This indicates that modulation of ergosterol level plays a key role in adaptation to oxidative stress. PMID:17016471

  2. Enzyme reaction engineering: synthesis of antibiotics catalysed by stabilized penicillin G acylase in the presence of organic cosolvents.

    PubMed

    Fernandez-Lafuente, R; Rosell, C M; Guisán, J M

    1991-11-01

    By using very active and very stable penicillin G acylase (PGA)--agarose derivatives we have studied the industrial design of equilibrium-controlled synthesis of lactamic antibiotics. In the presence of high concentrations of organic cosolvents we have carried out the direct enzymatic condensation of phenylacetic acid and 6-aminopenicillanic acid to yield the model antibiotic penicillin G. We have mainly studied the integrated effect of different variables that define the reaction medium on a number of parameters of industrial interest:time course of antibiotic synthesis, highest synthetic yields, stability of the catalyst, and solubility and stability of substrates and products. The main variables tested were the nature and concentration of the organic cosolvent, pH, and temperature. The effects of the variables tested on different parameters were quite different and sometimes opposite. Hence, the optimal experimental conditions for antibiotic synthesis catalysed by PGA were established, as a compromise solution, in order to obtain good values for every parameter of industrial interest. These conditions seem to be important parameters for scale-up (e.g. we have been able to reach more than 95% of synthetic yields with productivities around 0.5 tons of model antibiotic per year per liter of catalyst).

  3. Synthesis of modified maghemite nanoparticles and its application for removal of Acridine Orange from aqueous solutions by using Box-Behnken design

    NASA Astrophysics Data System (ADS)

    Bagheban Shahri, Fatemeh; Niazi, Ali

    2015-12-01

    In this study, sodium dodecyl sulfate-coated maghemite nanoparticles (SDS-coated γ-Fe2O3 NPs), was used for removal of cationic dye Acridine Orange from water samples. The γ-Fe2O3 NPs were synthesized by co-precipitation method and were characterized by scanning electron microscope (SEM) and vibrating sample magnetometer (VSM) to examine their size and magnetic moment. The adsorption experiments were performed using the batch system. The prepared magnetic adsorbent was well dispersed in water and easily separated magnetically from the medium after loaded with adsorbate. Four most important operating variables including initial pH of the solution, dosage of adsorbent, concentration of dye and contact time was studied and optimized by response surface methodology (RSM), involving Box-Behnken design matrix. Twenty-seven experiments were performed to investigate the effect of these parameters on removal of the dye. The results showed that initial pH of the solution was the most effective parameter in comparison with others. Also, experimental parameters were optimized and chose the best conditions by determination of effective factors. The optimized conditions for dye removal were at initial pH 5.1 0.8 g L-1 of adsorbent, 30.0 mg L-1 dye and 43 min adsorption time. The experimental data were analyzed by the Langmuir and Freundlich adsorption models. The maximum predicted adsorption capacities for Acridine Orange was 285.82 mg g-1.

  4. One pot synthesis of new hybrid versatile nanocarrier exhibiting efficient stability in biological environment for use in photodynamic therapy.

    PubMed

    Thienot, Edouard; Germain, Matthieu; Piejos, Kelthoum; Simon, Virginie; Darmon, Audrey; Marill, Julie; Borghi, Elsa; Levy, Laurent; Hochepied, Jean-François; Pottier, Agnès

    2010-07-01

    A new versatile hybrid nanocarrier has been designed using a "soft chemistry" synthesis, to efficiently encapsulate a photosensitizer - the protoporphyrin IX (Pp IX) - while preserving its activity intact in biological environment for advantageous use in photodynamic therapy (PDT). The synthesized Pp IX silica-based nanocarriers show to be spherical in shape and highly monodisperse with size extending from 10 nm up to 200 nm according to the synthesis procedure. Upon laser irradiation, the entrapped Pp IX shows to efficiently deliver reactive oxygen species (ROS) which are responsible for damaging tumor tissues. The ability of Pp IX silica-based nanocarriers to induce tumor cell death has been tested successfully in vitro. The stability of the Pp IX silica-based nanocarriers has been followed by UV-vis absorption and fluorescence emission in aqueous media and in 100% mouse serum media. The flexibility of the nanocarrier silica core has been examined as the key parameter to tune the Pp IX stability in biological environment. Indeed, an additional biocompatible inorganic surface coating performed on the Pp IX silica-based nanocarriers to produce an optimized bilayer coating demonstrates to significantly enhance the Pp IX stabilization in biological environments. Such versatile hybrid nanocarriers open new perspectives for PDT. PMID:20456971

  5. Glove box shield

    DOEpatents

    Brackenbush, L.W.; Hoenes, G.R.

    A shield for a glove box housing radioactive material is comprised of spaced apart clamping members which maintain three overlapping flaps in place therebetween. There is a central flap and two side flaps, the side flaps overlapping at the interior edges thereof and the central flap extending past the intersection of the side flaps in order to insure that the shield is always closed when the user wthdraws his hand from the glove box. Lead loaded neoprene rubber is the preferred material for the three flaps, the extent of lead loading depending upon the radiation levels within the glove box.

  6. Glove box shield

    DOEpatents

    Brackenbush, Larry W.; Hoenes, Glenn R.

    1981-01-01

    According to the present invention, a shield for a glove box housing radioactive material is comprised of spaced apart clamping members which maintain three overlapping flaps in place therebetween. There is a central flap and two side flaps, the side flaps overlapping at the interior edges thereof and the central flap extending past the intersection of the side flaps in order to insure that the shield is always closed when the user withdraws his hand from the glove box. Lead loaded neoprene rubber is the preferred material for the three flaps, the extent of lead loading depending upon the radiation levels within the glove box.

  7. Climate in a Box

    NASA Video Gallery

    NASA's Climate in a Box Project is exploring the utility of supercomputers in providing a complete, pre-packaged, ready-to-use toolkit of climate research products and on-demand access to a high-pe...

  8. Multi-color carrier-envelope-phase stabilization for high-repetition-rate multi-pulse coherent synthesis.

    PubMed

    McCracken, Richard A; Gianani, Ilaria; Wyatt, Adam S; Reid, Derryck T

    2015-04-01

    Using a zero-offset carrier-envelope locking technique, we have synthesized an octave-spanning composite frequency comb exhibiting 132-attosecond timing jitter between the constituent pulses over a one-second observation window. In the frequency domain, this composite comb has a modal structure and coherence which are indistinguishable from those of a comb that might be produced by a hypothetical single mode locked oscillator of equivalent bandwidth. The associated phase stability enables the participating multi-color pulse sequences to be coherently combined, representing an example of multi-pulse synthesis using a femtosecond oscillator.

  9. Automatic box loader

    DOEpatents

    Eldridge, Harry H.; Jones, Robert A.; Lindner, Gordon M.; Hight, Paul H.

    1976-01-01

    This invention relates to a system for repetitively forming an assembly consisting of a single layer of tubes and a row of ferromagnetic armatures underlying the same, electromagnetically conveying the resulting assembly to a position overlying a storage box, and depositing the assembly in the box. The system includes means for simultaneously depositing a row of the armatures on the inclined surface of a tube retainer. Tubes then are rolled down the surface to form a single tube layer bridging the armatures. A magnet assembly carrying electromagnets respectively aligned with the armatures is advanced close to the tube layer, and in the course of this advance is angularly displaced to bring the pole pieces of the electromagnets into parallelism with the tube layer. The magnets then are energized to pick up the assembly. The loaded magnet assembly is retracted to a position overlying the box, and during this retraction is again displaced to bring the pole pieces of the electromagnets into a horizontal plane. Means are provided for inserting the loaded electromagnets in the box and then de-energizing the electromagnets to deposit the assembly therein. The system accomplishes the boxing of fragile tubes at relatively high rates. Because the tubes are boxed as separated uniform layers, subsequent unloading operations are facilitated.

  10. Phase Stability Analysis of Lanthanum-Doped Alumina During Synthesis and Sintering

    NASA Astrophysics Data System (ADS)

    Ngwa Nforbi, Lum-Ngwegia

    The aim of this research was to study the phase stability during synthesis and consolidation of nanocrystalline lanthanum-doped gamma-Al2O 3 powders. We used solution combustion synthesis by dissolving precursor nitrate compounds and an organic fuel in a pre-heated muffle furnace at 500°C. Several preliminary syntheses were carried out in order to obtain the correct fuel-to-oxidizer ratio necessary for the production of the desired lanthanum-doped gamma-Al 2O3. The as-synthesized powders were then heat-treated at 1000°C for 2 hours in order to remove impurities and improve the crystallinity of the powders. Sintered circular specimens were made by pressing the heat-treated powders and subsequently annealing them at 1800°C for 4 hours. The use of this material in optical windows requires that the material have high strength and optical transparency. Elimination of all the pores during sintering is therefore crucial. In addition, preparing specimens of the gamma-Al2O3 phase is optimal, since the crystal structure is cubic and transparency is more readily achievable. Several different samples with varying weight percents of La were attempted to determine how much of the La could effectively prevent the gamma-Al2O 3 phase from transforming into the more stable alpha-Al2O 3 phase. The different phases of compounds produced with increasing amounts of La were also identified. The as-synthesized and heat-treated powders as well as the annealed circular discs were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The average particle sizes of the powders were determined by dynamic light scattering (DLS). XRD experiments showed that the gamma-alumina phase was stabilized when the powders were calcined at 1000°C with 5 wt% La, 10 wt% La and 13 wt% La. Increasing the amount of La resulted in the formation of the La compounds LaAlO3 in the heat-treated powders containing 15 wt% La and above and LaAl11O18 in the sintered specimens. Crystallite

  11. Synthesis of linear and cyclic peptide-PEG-lipids for stabilization and targeting of cationic liposome-DNA complexes.

    PubMed

    Ewert, Kai K; Kotamraju, Venkata Ramana; Majzoub, Ramsey N; Steffes, Victoria M; Wonder, Emily A; Teesalu, Tambet; Ruoslahti, Erkki; Safinya, Cyrus R

    2016-03-15

    Because nucleic acids (NAs) have immense potential value as therapeutics, the development of safe and effective synthetic NA vectors continues to attract much attention. In vivo applications of NA vectors require stabilized, nanometer-scale particles, but the commonly used approaches of steric stabilization with a polymer coat (e.g., PEGylation; PEG=poly(ethylene glycol)) interfere with attachment to cells, uptake, and endosomal escape. Conjugation of peptides to PEG-lipids can improve cell attachment and uptake for cationic liposome-DNA (CL-DNA) complexes. We present several synthetic approaches to peptide-PEG-lipids and discuss their merits and drawbacks. A lipid-PEG-amine building block served as the common key intermediate in all synthetic routes. Assembling the entire peptide-PEG-lipid by manual solid phase peptide synthesis (employing a lipid-PEG-carboxylic acid) allowed gram-scale synthesis but is mostly applicable to linear peptides connected via their N-terminus. Conjugation via thiol-maleimide or strain-promoted (copper-free) azide-alkyne cycloaddition chemistry is highly amenable to on-demand preparation of peptide-PEG-lipids, and the appropriate PEG-lipid precursors are available in a single chemical step from the lipid-PEG-amine building block. Azide-alkyne cycloaddition is especially suitable for disulfide-bridged peptides such as iRGD (cyclic CRGDKGPDC). Added at 10 mol% of a cationic/neutral lipid mixture, the peptide-PEG-lipids stabilize the size of CL-DNA complexes. They also affect cell attachment and uptake of nanoparticles in a peptide-dependent manner, thereby providing a platform for preparing stabilized, affinity-targeted CL-DNA nanoparticles. PMID:26874401

  12. Cable Tester Box

    NASA Technical Reports Server (NTRS)

    Lee, Jason H.

    2011-01-01

    Cables are very important electrical devices that carry power and signals across multiple instruments. Any fault in a cable can easily result in a catastrophic outcome. Therefore, verifying that all cables are built to spec is a very important part of Electrical Integration Procedures. Currently, there are two methods used in lab for verifying cable connectivity. (1) Using a Break-Out Box and an ohmmeter this method is time-consuming but effective for custom cables and (2) Commercial Automated Cable Tester Boxes this method is fast, but to test custom cables often requires pre-programmed configuration files, and cables used on spacecraft are often uniquely designed for specific purposes. The idea is to develop a semi-automatic continuity tester that reduces human effort in cable testing, speeds up the electrical integration process, and ensures system safety. The JPL-Cable Tester Box is developed to check every single possible electrical connection in a cable in parallel. This system indicates connectivity through LED (light emitting diode) circuits. Users can choose to test any pin/shell (test node) with a single push of a button, and any other nodes that are shorted to the test node, even if they are in the same connector, will light up with the test node. The JPL-Cable Tester Boxes offers the following advantages: 1. Easy to use: The architecture is simple enough that it only takes 5 minutes for anyone to learn how operate the Cable Tester Box. No pre-programming and calibration are required, since this box only checks continuity. 2. Fast: The cable tester box checks all the possible electrical connections in parallel at a push of a button. If a cable normally takes half an hour to test, using the Cable Tester Box will improve the speed to as little as 60 seconds to complete. 3. Versatile: Multiple cable tester boxes can be used together. As long as all the boxes share the same electrical potential, any number of connectors can be tested together.

  13. Green chemistry approach for the synthesis and stabilization of biocompatible gold nanoparticles and their potential applications in cancer therapy.

    PubMed

    Mukherjee, Sudip; Sushma, V; Patra, Sujata; Barui, Ayan Kumar; Bhadra, Manika Pal; Sreedhar, Bojja; Patra, Chitta Ranjan

    2012-11-16

    The biological approach to synthesis of AuNPs is eco-friendly and an ideal method to develop environmentally sustainable nanoparticles alternative to existing methods. We have developed a simple, fast, clean, efficient, low-cost and eco-friendly single-step green chemistry approach for the synthesis of biocompatible gold nanoparticles (AuNPs) from chloroauric acid (HAuCl(4)) using a water extract of Eclipta Alba leaves at room temperature. The AuNPs using Eclipta extract have been formed in very short time, even in less than 10 min. The as-synthesized AuNPs were thoroughly characterized by several physico-chemical techniques. The in vitro stability of as-synthesized AuNPs was studied in different buffer solutions. A plausible mechanism for the synthesis of AuNPs by Eclipta extract has been discussed. The biocompatibility of AuNPs was observed by in vitro cell culture assays. Finally, we have designed and developed a AuNPs-based drug delivery system (DDS) (Au-DOX) containing doxorubicin (DOX), a FDA approved anticancer drug. Administration of this DDS to breast cancer cells (MCF-7 and MDA-MB-231) shows significant inhibition of breast cancer cell proliferation compared to pristine doxorubicin. Therefore we strongly believe that the use of Eclipta Alba offers large-scale production of biocompatible AuNPs that can be used as a delivery vehicle for the treatment of cancer diseases. PMID:23064012

  14. Improved activity and stability of Rhizopus oryzae lipase via immobilization for citronellol ester synthesis in supercritical carbon dioxide.

    PubMed

    Dhake, Kishor P; Deshmukh, Krishna M; Patil, Yogesh P; Singhal, Rekha S; Bhanage, Bhalchandra M

    2011-10-20

    In present work, Rhizopus oryzae lipase immobilized on a film prepared using blend of hydroxylpropyl methyl cellulose (HPMC) and polyvinyl alcohol (PVA) was investigated for synthesis of citronellol esters with supercritical carbon dioxide (Sc-CO(2)) as a reaction medium. The transesterification reaction was optimized for various reaction parameters like effect of molar ratio, acyl donor, time, temperature, enzyme concentration, effect of pressure and co-solvent to achieve the maximum yield of desired product. The results obtained signify remarkable increment (about eightfold) in the yield of citronellol acetate (91%) as compared to that of free lipase (11%) in Sc-CO(2). The developed biocatalytic methodology provides a substantial advantage of low biocatalyst loading (1.5%, w/v), lower reaction temperature (45°C) and lower pressure (8 MPa) as compared to previous reports. The immobilization method has significantly enhanced the operational stability of lipase for ester synthesis under Sc-CO(2) conditions. The developed methodology was successfully applied for synthesis of three different industrially important citronellol esters namely citronellol acetate (91%), citronellol butyrate (98%), citronellol laurate (99%) with excellent yields using vinyl esters as acyl donor under Sc-CO(2) conditions. In addition, the immobilized biocatalyst was effectively recycled for three consecutive recycles. PMID:21884733

  15. Green chemistry approach for the synthesis and stabilization of biocompatible gold nanoparticles and their potential applications in cancer therapy.

    PubMed

    Mukherjee, Sudip; Sushma, V; Patra, Sujata; Barui, Ayan Kumar; Bhadra, Manika Pal; Sreedhar, Bojja; Patra, Chitta Ranjan

    2012-11-16

    The biological approach to synthesis of AuNPs is eco-friendly and an ideal method to develop environmentally sustainable nanoparticles alternative to existing methods. We have developed a simple, fast, clean, efficient, low-cost and eco-friendly single-step green chemistry approach for the synthesis of biocompatible gold nanoparticles (AuNPs) from chloroauric acid (HAuCl(4)) using a water extract of Eclipta Alba leaves at room temperature. The AuNPs using Eclipta extract have been formed in very short time, even in less than 10 min. The as-synthesized AuNPs were thoroughly characterized by several physico-chemical techniques. The in vitro stability of as-synthesized AuNPs was studied in different buffer solutions. A plausible mechanism for the synthesis of AuNPs by Eclipta extract has been discussed. The biocompatibility of AuNPs was observed by in vitro cell culture assays. Finally, we have designed and developed a AuNPs-based drug delivery system (DDS) (Au-DOX) containing doxorubicin (DOX), a FDA approved anticancer drug. Administration of this DDS to breast cancer cells (MCF-7 and MDA-MB-231) shows significant inhibition of breast cancer cell proliferation compared to pristine doxorubicin. Therefore we strongly believe that the use of Eclipta Alba offers large-scale production of biocompatible AuNPs that can be used as a delivery vehicle for the treatment of cancer diseases.

  16. Green chemistry approach for the synthesis and stabilization of biocompatible gold nanoparticles and their potential applications in cancer therapy

    NASA Astrophysics Data System (ADS)

    Mukherjee, Sudip; Sushma, V.; Patra, Sujata; Barui, Ayan Kumar; Pal Bhadra, Manika; Sreedhar, Bojja; Ranjan Patra, Chitta

    2012-11-01

    The biological approach to synthesis of AuNPs is eco-friendly and an ideal method to develop environmentally sustainable nanoparticles alternative to existing methods. We have developed a simple, fast, clean, efficient, low-cost and eco-friendly single-step green chemistry approach for the synthesis of biocompatible gold nanoparticles (AuNPs) from chloroauric acid (HAuCl4) using a water extract of Eclipta Alba leaves at room temperature. The AuNPs using Eclipta extract have been formed in very short time, even in less than 10 min. The as-synthesized AuNPs were thoroughly characterized by several physico-chemical techniques. The in vitro stability of as-synthesized AuNPs was studied in different buffer solutions. A plausible mechanism for the synthesis of AuNPs by Eclipta extract has been discussed. The biocompatibility of AuNPs was observed by in vitro cell culture assays. Finally, we have designed and developed a AuNPs-based drug delivery system (DDS) (Au-DOX) containing doxorubicin (DOX), a FDA approved anticancer drug. Administration of this DDS to breast cancer cells (MCF-7 and MDA-MB-231) shows significant inhibition of breast cancer cell proliferation compared to pristine doxorubicin. Therefore we strongly believe that the use of Eclipta Alba offers large-scale production of biocompatible AuNPs that can be used as a delivery vehicle for the treatment of cancer diseases.

  17. Box truss antenna technology status

    NASA Technical Reports Server (NTRS)

    Coyner, J. V.; Bachtell, E. E.

    1987-01-01

    Recent technology development activities for box truss structures and box truss antennas are summarized. Three primary activities are discussed: the development of an integrated analysis system for box truss mesh antennae; dynamic testing to characterize the effect of joint free play on the dynamic behavior of box truss structures; and fabrication of a 4.5 meter diameter offset fed mesh reflector integrated to an all graphite epoxy box truss cube.

  18. CdTe quantum dots: aqueous phase synthesis, stability studies and protein conjugation for development of biosensors

    NASA Astrophysics Data System (ADS)

    Borse, Vivek; Sadawana, Mayur; Srivastava, Rohit

    2016-04-01

    Synthesis of quantum dots (QDs) in aqueous medium is advantageous as compared to the organic solvent mediated synthesis, as the aqueous synthesis is less toxic, reagent effective, easily reproducible and importantly, synthesized QDs have biological compatibility. The QDs should be aqueous in nature for use in cell imaging, drug labeling, tracking and delivery. Structural modifications are necessary to enable their use in biosensing application. In this work, mercaptopropionic acid capped cadmium telluride QDs (MPA-CdTe QDs) were synthesized by hydrothermal method and characterized by various techniques. Water and various biochemical buffers were used to study the fluorescence intensity stability of the QDs at different physicochemical conditions. QDs stored in 4° C showed excellent stability of fluorescence intensity values as compared to the samples stored at room temperature. Staphylococcal protein A (SPA) was conjugated with the QDs (SPA-QDs) and characterized using UV and fluorescence spectroscopy, zeta potential, HRTEM, FTIR, and AFM. Blue shift was observed in the fluorescence emission spectra that may be due to reduction in the surface charge as carboxyl groups on QDs were replaced by amino groups of SPA. This SPA conjugated to QDs enables binding of the C-terminal of antibodies on its surface allowing N-terminal binding site remain free to bind with antigenic biomarkers. Thus, the biosensor i.e. antibody bound on SPA-QDs would bind to the antigenic biomarkers in sample and the detection system could be developed. As QDs have better fluorescence properties than organic dyes, this biosensor will provide high sensitivity and quantitative capability in diagnostics.

  19. Synthesis of chiral networks for polymer stabilized cholesteric texture (PSCT) displays

    SciTech Connect

    Rego, J.A.; Cahill, P.A.

    1997-03-01

    New mono- and di-functional polymerizable twist agents for formation of polymer stabilized cholesteric texture liquid crystal displays have been synthesized. Degree of crosslinking has a pronounced effect on electrooptic response of the cell and the stability of oriented states.

  20. A study on the stability and green synthesis of silver nanoparticles using Ziziphora tenuior (Zt) extract at room temperature

    NASA Astrophysics Data System (ADS)

    Sadeghi, Babak; Gholamhoseinpoor, F.

    2015-01-01

    Biomolecules present in plant extracts can be used to reduce metal ions to nanoparticles in a single-step green synthesis process. This biogenic reduction of metal ion to base metal is quite rapid, readily conducted at room temperature and pressure, and easily scaled up. Mediated Synthesis by plant extracts is environmentally benign. The involved reducing agents include the various water soluble plant metabolites (e.g. alkaloids, phenolic compounds, terpenoids) and co-enzymes. Silver (Ag) nanoparticles have the particular focus of plant-based syntheses. Extracts of a diverse range of Ziziphora tenuior (Zt) have been successfully used in making nanoparticles. The aim of this study was to investigate the antioxidant properties of this plant and its ability to synthesize silver nanoparticles. Z.tenuior leaves were used to prepare the aqueous extract for this study. Silver nanoparticles were characterized with different techniques such as UV-vis spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Transmission electron microscopy experiments showed that these nanoparticles are spherical and uniformly distributed and its size is from 8 to 40 nm. FT-IR spectroscopy revealed that silver nanoparticles were functionalized with biomolecules that have primary amine group (sbnd NH2), carbonyl group, sbnd OH groups and other stabilizing functional groups. X-ray diffraction pattern showed high purity and face centered cubic structure of silver nanoparticles with size of 38 nm. In addition to plant extracts, live plants can be used for the synthesis. Here were view the methods of making nanoparticles using plant extracts. The scanning electron microscopy (SEM) implies the right of forming silver nanoparticles. The results of TEM, SEM, FT-IR, UV-VIS and XRD confirm that the leaves extract of Zt can synthesis silver nanoparticles.

  1. Depth in box spaces.

    PubMed

    Pont, Sylvia C; Nefs, Harold T; van Doorn, Andrea J; Wijntjes, Maarten W A; Te Pas, Susan F; de Ridder, Huib; Koenderink, Jan J

    2012-01-01

    Human observers adjust the frontal view of a wireframe box on a computer screen so as to look equally deep and wide, so that in the intended setting the box looks like a cube. Perspective cues are limited to the size-distance effect, since all angles are fixed. Both the size on the screen, and the viewing distance from the observer to the screen were varied. All observers prefer a template view of a cube over a veridical rendering, independent of picture size and viewing distance. If the rendering shows greater or lesser foreshortening than the template, the box appears like a long corridor or a shallow slab, that is, like a 'deformed' cube. Thus observers ignore 'veridicality'. This does not fit an 'inverse optics' model. We discuss a model of 'vision as optical user interface'.

  2. Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N4-methyl-3-thiosemicarbazone: Crystal structure of a novel sulfur bridged copper(II) box-dimer

    NASA Astrophysics Data System (ADS)

    Jayakumar, K.; Sithambaresan, M.; Aiswarya, N.; Kurup, M. R. Prathapachandra

    2015-03-01

    Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N4-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ = 0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)sbnd I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g|| > g⊥ > 2.0023 and the g values in frozen DMF are consistent with the dx2-y2 ground state. The thermal stabilities of some of the complexes were also determined.

  3. Synthesis and Characterisation of Biocompatible Polymer-Conjugated Magnetic Beads for Enhancement Stability of Urease.

    PubMed

    Doğaç, Yasemin Ispirli; Teke, Mustafa

    2016-04-01

    We reported natural polymer-conjugated magnetic featured urease systems for removal of urea effectively. The optimum temperature (20-60 °C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70 °C), pH stability (4.0-9.0), operational stability (0-250 min), reusability (18 times) and storage stability (24 weeks) were studied for characterisation of the urease-encapsulated biocompatible polymer-conjugated magnetic beads. Also, the surface groups and chemical structure of the magnetic beads were determined by using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The all urease-encapsulated magnetic beads protected their stability of 30-45 % relative activity at 70 °C. A significant increase was observed at their pH stability compared with the free urease for both acidic and alkaline medium. Besides this, their repeatability activity were approximately 100 % during 4(th) run. They showed residual activity of 50 % after 16 weeks. The importance of this work is enhancement stability of immobilised urease by biocompatible polymer-conjugated magnetic beads for the industrial application based on removal of urea.

  4. Synthesis of a combined precision stabilization system for a space telescope

    NASA Astrophysics Data System (ADS)

    Kozlov, R. I.; Druzhynin, E. I.; Ulyanov, S. A.; Voronov, V. A.; Belyaev, B. B.

    2012-11-01

    Some results of the investigation related to design of a precision stabilization system for a high-orbit space telescope with flexible elements, whose contribution to the inertia tensor reaches 80%, are discussed. The stabilization system represents a combined control system with open and closed control loops, in which the actuators are represented by a gyro system having four control moment gyros and four reactive wheels. The open loop control is employed to orient the telescope's optical axis to the attraction domain in accordance with the feedback control law. The closed loop is used both in the slewing mode for stabilizing programmed motions and in the basic (fine pointing) mode.

  5. Synthesis, characterization, and controlled release of selenium nanoparticles stabilized by chitosan of different molecular weights.

    PubMed

    Zhang, Chunyue; Zhai, Xiaona; Zhao, Guanghua; Ren, Fazheng; Leng, Xiaojing

    2015-12-10

    Chitosan-stabilized selenium nanoparticles (SeNPs) have been reported, but there is no information on the effect of the chitosan molecular weight on the structure, stability, and selenium release properties of the SeNPs. Herein, we compared the uniform Se(0) spherical nanoparticles prepared through the reduction of seleninic acid with ascorbic acid in the presence of chitosan with different molecular weights (Mws). We found that both low and high molecular weight chitosan-stabilized selenium nanoparticles exhibited core-shell microstructures with a size of about 103 nm after 30 days growing through the "bottom-up approach" and "top-down approach," respectively. Moreover, both chitosan SeNPs processed excellent stability towards pH and enzyme treatment. In contrast, selenium was easily released to different extents from these two chitosan SeNPs upon treatment with different free radicals. This makes these materials potentially useful as oral antioxidant supplements. PMID:26428112

  6. Synthesis, characterization, and controlled release of selenium nanoparticles stabilized by chitosan of different molecular weights.

    PubMed

    Zhang, Chunyue; Zhai, Xiaona; Zhao, Guanghua; Ren, Fazheng; Leng, Xiaojing

    2015-12-10

    Chitosan-stabilized selenium nanoparticles (SeNPs) have been reported, but there is no information on the effect of the chitosan molecular weight on the structure, stability, and selenium release properties of the SeNPs. Herein, we compared the uniform Se(0) spherical nanoparticles prepared through the reduction of seleninic acid with ascorbic acid in the presence of chitosan with different molecular weights (Mws). We found that both low and high molecular weight chitosan-stabilized selenium nanoparticles exhibited core-shell microstructures with a size of about 103 nm after 30 days growing through the "bottom-up approach" and "top-down approach," respectively. Moreover, both chitosan SeNPs processed excellent stability towards pH and enzyme treatment. In contrast, selenium was easily released to different extents from these two chitosan SeNPs upon treatment with different free radicals. This makes these materials potentially useful as oral antioxidant supplements.

  7. 6. VIEW OF INTERIOR GLOVE BOX DURING CONSTRUCTION. GLOVE BOXES ...

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

    6. VIEW OF INTERIOR GLOVE BOX DURING CONSTRUCTION. GLOVE BOXES CONTAINED ALL PRODUCTION OPERATIONS AND WERE INTERCONNECTED BY CONVEYORS. (9/21/59) - Rocky Flats Plant, Plutonium Fabrication, Central section of Plant, Golden, Jefferson County, CO

  8. Looking Southwest at Reactor Box Furnaces With Reactor Boxes and ...

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

    Looking Southwest at Reactor Box Furnaces With Reactor Boxes and Repossessed Uranium in Recycle Recovery Building - Hematite Fuel Fabrication Facility, Recycle Recovery Building, 3300 State Road P, Festus, Jefferson County, MO

  9. Teaching with Box Tops.

    ERIC Educational Resources Information Center

    Raiser, Lynne; D'Zamko, Mary Elizabeth

    1984-01-01

    Using environmental materials (such as the phone book and placemats from fast food restaurants) can be a motivating way to teach learning disabled students skills and concepts, as shown in an approach to reading, math, science and nutrition, and social studies instruction using a JELL-O brand gelatin box. (CL)

  10. Thinking "Inside" the Box

    ERIC Educational Resources Information Center

    Jeffries, Carolyn

    2011-01-01

    The authors conducted a test to determine whether they could incorporate a discovery box into a preschool setting was successful. It stimulated the students' natural inquiry processes while promoting understanding of healthy foods and allowing for practice of fine-motor skills. It was easily incorporated into the curriculum and classroom space.…

  11. Hydrophobic, Porous Battery Boxes

    NASA Technical Reports Server (NTRS)

    Bragg, Bobby J.; Casey, John E., Jr.

    1995-01-01

    Boxes made of porous, hydrophobic polymers developed to contain aqueous potassium hydroxide electrolyte solutions of zinc/air batteries while allowing air to diffuse in as needed for operation. Used on other types of batteries for in-cabin use in which electrolytes aqueous and from which gases generated during operation must be vented without allowing electrolytes to leak out.

  12. Cereal Box Totems.

    ERIC Educational Resources Information Center

    Jones, AnnMarie

    2002-01-01

    Presents a multicultural project used with fourth-grade students in which they created a three-dimensional totem pole using leftover cereal boxes. Discusses in detail how to create the totem pole. Explains that students learned about Northwest American Indians in class. (CMK)

  13. Sand-box modelling

    SciTech Connect

    Avery, P.

    1983-01-01

    As the result of an enquiry into BHRA's physical-reservoir-modelling experience, the use of sand box models was investigated. The type of model was considered a possible means of confirmation of a numerical model. The problem facing the numerical model user was comparing the performance of inclined or horizontal oil wells with that of the conventional vertical well.

  14. Science in a Box.

    ERIC Educational Resources Information Center

    Learning, 1991

    1991-01-01

    The ninth installment of the Science in a Box series (self-contained, hands-on activities for students grades three and up) presents activities for learning to use the sense of touch to determine how different objects conduct heat. All projects in the series are inexpensive and easy to assemble. (SM)

  15. Mystery Box Marvels

    ERIC Educational Resources Information Center

    Santos, Joel; Centurio, Tina

    2012-01-01

    What happens in the first week of school could very well set the stage for the rest of the school year. Setting high standards for science activities based in inquiry can start on the first day of science class and develop as the year unfolds. With the use of simple, readily available, inexpensive materials, an efficient mystery box lesson can be…

  16. "Can" the Black Box

    ERIC Educational Resources Information Center

    Lestingi, Francis S.

    1975-01-01

    Describes the use of the "Arcane (mysterious) Can" which is a "tin" can which is permanently sealed, both air- and water-tight, by means of a home canning device. The canning procedure permits the use of a large variety of materials which can not be utilized in the ordinary mystery box. This Can activity is valuable for illustrating in an…

  17. Shoe Box Circuits

    ERIC Educational Resources Information Center

    Sandifer, Cody

    2009-01-01

    Students' eyes grow wide with wonder as they get a motor to work or make a bulb light for the first time. As these daunting feats of electrical engineering remind us, teaching electricity is invariably rewarding and worthwhile. In this inquiry-based science project, elementary students work in pairs to design and wire a shoe box "room" that meets…

  18. The synthesis of starch from carbon dioxide using isolubilized stabilized enzymes

    NASA Technical Reports Server (NTRS)

    Bassham, J. A.; Bearden, L.; Wilke, C.; Carroad, P.; Mitra, G.; Ige, R.

    1972-01-01

    Systems for artificial manufacture of starch and for delineation of technological areas, and the rationale for studying them are considered. A discussion of the enzyme-catalyzed routes of synthesis available and a choice as to the most promising route are presented. A discussion of the enzymes involved, of enzyme insolubilization technology, and of possible engineering approaches, with examples in the form of model calculations for both reactors and separators, are also presented.

  19. Facile Synthesis of Phosphatidyl Saccharides for Preparation of Anionic Nanoliposomes with Enhanced Stability

    PubMed Central

    Song, Shuang; Cheong, Ling-Zhi; Falkeborg, Mia; Liu, Lei; Dong, Mingdong; Jensen, Henrik Max; Bertelsen, Kresten; Thorsen, Michael; Tan, Tianwei; Xu, Xuebing; Guo, Zheng

    2013-01-01

    Physical stability during storage and against processing such as dehyration/rehydration are the cornerstone in designing delivery vehicles. In this work, mono-, di- and tri-saccharides were enzymatically conjugated to phosphatidyl group through a facile approach namely phospholipase D (PLD) mediated transphosphatidylation in a biphasic reaction system. The purified products were structurally identified and the connectivities of carbohydrate to phosphatidyl moiety precisely mapped by 1H, 31P, 13C NMR pulse sequences and LC-ESI-FTMS. The synthetic phosphatidyl saccharides were employed as the sole biomimetic component for preparation of nanoliposomes. It was found that the critical micelle concentration (CMC) of phosphatidyl saccharides increases as more bulky sugar moiety (mono- to tri-) is introduced. Phosphatidyl di-saccharide had the largest membrane curvature. In comparison to the zwitterionic phosphatidylcholine liposome, all phosphatidyl saccharides liposomes are anionic and demonstrated significantly enhanced stability during storage. According to the confocal laser scan microscopy (CLSM) and atom force microscopy (AFM) analyses, the nanoliposomes formed by the synthetic phosphatidyl saccharides also show excellent stability against dehydration/rehydration process in which most of the liposomal structures remained intact. The abundance hydroxyl groups in the saccharide moieties might provide sufficient H-bondings for stabilization. This work demonstrated the synthesized phosphatidyl saccharides are capable of functioning as enzymatically liable materials which can form stable nanoliposomes without addition of stabilizing excipients. PMID:24069243

  20. Synthesis, phase stability and electrical conductivity of Sr{sub 2}MgMoO{sub 6-{delta}} anode

    SciTech Connect

    Marrero-Lopez, D. Pena-Martinez, J.; Ruiz-Morales, J.C.; Perez-Coll, D.; Aranda, M.A.G.; Nunez, P.

    2008-08-04

    A freeze-drying precursor method has been used to prepare polycrystalline materials of the new SOFC anode, Sr{sub 2}MgMoO{sub 6-{delta}}. The optimal synthesis conditions were studied in order to avoid secondary phase segregations. These materials were characterised by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermal analysis (TG/DTA) and scanning electron microscopy (SEM). The as-synthesised polycrystalline powders showed homogeneous particle size distribution in the submicrometric range. The stability studies demonstrated that this phase is stable up to 1200 deg. C under 5% H{sub 2}-Ar. In addition, impedance spectroscopy was used to determine the conductivity of ceramic pellets prepared under oxidising and reducing atmosphere. Samples sintered in reducing atmosphere exhibit higher conductivity values than those prepared in air.

  1. Phase stability and rapid consolidation of hydroxyapatite-zirconia nano-coprecipitates made using continuous hydrothermal flow synthesis.

    PubMed

    Chaudhry, Aqif A; Yan, Haixue; Viola, Giuseppe; Reece, Mike J; Knowles, Jonathan C; Gong, Kenan; Rehman, Ihtesham; Darr, Jawwad A

    2012-07-01

    A rapid and continuous hydrothermal route for the synthesis of nano-sized hydroxyapatite rods co-precipitated with calcium-doped zirconia nanoparticles using a superheated water flow at 450°C and 24.1 MPa as a crystallizing medium is described. Hydroxyapatite and calcium-doped zirconia phases in the powder mixtures could be clearly identified based on particle size and morphology under transmission electron microscopy. Retention of a nanostructure after sintering is crucial to load-bearing applications of hydroxyapatite-based ceramics. Therefore, rapid consolidation of the co-precipitates was investigated using a spark plasma sintering furnace under a range of processing conditions. Samples nominally containing 5 and 10 wt% calcium-doped zirconia and hydroxyapatite made with Ca:P solution molar ratio 2.5 showed excellent thermal stability (investigated using in situ variable temperature X-ray diffraction) and were sintered via spark plasma sintering to >96% sintered densities at 1000°C resulting in hydroxyapatite and calcium-doped zirconia as the only two phases. Mechanical tests of spark plasma sintering sintered samples (containing 10 wt% calcium-doped zirconia) revealed a three-pt flexural strength of 107.7 MPa and Weibull modulus of 9.9. The complementary nature of the spark plasma sintering technique and continuous hydrothermal flow synthesis (which results in retention of a nanostructure even after sintering at elevated temperatures) was hence showcased.

  2. Synthesis and high (pressure, temperature) stability of ZnTiO3 polymorphs studied by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Bernert, T.; Ruiz-Fuertes, J.; Bayarjargal, L.; Winkler, B.

    2015-05-01

    The phase-purity of ilmenite-type ZnTiO3 prepared by the ceramic method was investigated in dependence of the conditions during ball milling. The previously proposed addition of 2 ml ethanol to the starting materials led to a significant contamination of the product phase after a subsequent sintering process at 1073 K. However, by omitting ethanol this synthesis route led to a phase-pure sample of ZnTiO3 as confirmed by X-ray powder diffraction and Raman spectroscopy. High-temperature high-pressure experiments gave an ilmenite-type to perovskite-type phase boundary with a slope of dT/dP∼-135 K GPa-1 crossing ambient temperature conditions at ∼ 24 GPa in good agreement with previous calculations. Room-temperature high-pressure Raman spectroscopy experiments have shown the stability of the ilmenite-type phase up to a pressure of at least 38.5 GPa, the highest pressure applied in this study, indicating the presence of a kinetic barrier in this phase transition. The synthesis of ferroelectric LiNbO3-type ZnTiO3 was confirmed by second harmonic generation.

  3. Synthesis of gold nanoparticles on the surface of pyrolytic graphite using penicillin as a stabilizing reagent and the catalytic oxidation of α-naphthylamine

    NASA Astrophysics Data System (ADS)

    Song, Y. Z.; Song, Y.; Cheng, Z. P.; Zhou, J. F.; Wei, C.

    2013-01-01

    Electrochemical synthesis of gold nanoparticles on the surface of pyrolytic graphite using penicillin as a stabilizing reagent was proposed. The gold nanoparticles were characterized by scanning electron microscopy, cyclic voltammetry, IR spectra, UV spectra, and powder X-ray diffraction spectra. The electro-chemical catalysis of penicillin for α-naphthylamine was demonstrated.

  4. Synthesis of polysubstituted β-amino cyclohexane carboxylic acids via Diels-Alder reaction using Ni(II)-complex stabilized β-alanine derived dienes.

    PubMed

    Ding, Xiao; Wang, Hengshuai; Wang, Jiang; Wang, Sinan; Lin, Daizong; Lv, Li; Zhou, Yu; Luo, Xiaomin; Jiang, Hualiang; Aceña, José Luis; Soloshonok, Vadim A; Liu, Hong

    2013-02-01

    This paper describes the design and synthesis of a new class of β-alanine derived dienes stabilized by Ni(II)-complex. Preliminary study of their Diels-Alder cycloaddition reactions with several types of dienophiles demonstrates their significant synthetic potential for the preparation of various polyfunctional β-aminocyclohexane carboxylic acids.

  5. Hermit Points on a Box

    ERIC Educational Resources Information Center

    Hess, Richard; Grinstead, Charles; Grindstead, Marshall; Bergstrand, Deborah

    2008-01-01

    Suppose that we are given a rectangular box in 3-space. Given any two points on the surface of this box, we can define the surface distance between them to be the length of the shortest path between them on the surface of the box. This paper determines the pairs of points of maximum surface distance for all boxes. It is often the case that these…

  6. Making Connections with Memory Boxes.

    ERIC Educational Resources Information Center

    Whatley, April

    2000-01-01

    Addresses the use of children's literature within the social studies classroom on the topic of memory boxes. Includes discussions of four books: (1) "The Littlest Angel" (Charles Tazewell); (2) "The Hundred Penny Box" (Sharon Bell Mathis); (3) "Wilfrid Gordon McDonald Partridge" (Mem Fox); and (4) "The Memory Box" (Mary Bahr). (CMK)

  7. Synthesis of Mevalonate- and Fluorinated Mevalonate Prodrugs and Their in vitro Human Plasma Stability

    PubMed Central

    Kang, Soosung; Watanabe, Mizuki; Jacobs, JC; Yamaguchi, Masaya; Dahesh, Samira; Nizet, Victor; Leyh, Thomas S.; Silverman, Richard B.

    2014-01-01

    The mevalonate pathway is essential for the production of many important molecules in lipid biosynthesis. Inhibition of this pathway is the mechanism of statin cholesterol-lowering drugs, as well as the target of drugs to treat osteoporosis, to combat parasites, and to inhibit tumor cell growth. Unlike the human mevalonate pathway, the bacterial pathway appears to be regulated by diphosphomevalonate (DPM). Enzymes in the mevalonate pathway act to produce isopentenyl diphosphate, the product of the DPM decarboxylase reaction, utilize phosphorylated (charged) intermediates, which are poorly bioavailable. It has been shown that fluorinated DPMs (6-fluoro- and 6,6,6-trifluoro-5-diphosphomevalonate) are excellent inhibitors of the bacterial pathway; however, highly charged DPM and analogues are not bioavailable. To increase cellular permeability of mevalonate analogues, we have synthesized various prodrugs of mevalonate and 6-fluoro- and 6,6,6-trifluoromevalonate that can be enzymatically transformed to the corresponding DPM or fluorinated DPM analogues by esterases or amidases. To probe the required stabilities as potentially bioavailable prodrugs, we measured the half-lives of esters, amides, carbonates, acetals, and ketal promoieties of mevalonate and the fluorinated mevalonate analogues in human blood plasma. Stability studies showed that the prodrugs are converted to the mevalonates in human plasma with a wide range of half-lives. These studies provide stability data for a variety of prodrug options having varying stabilities and should be very useful in the design of appropriate prodrugs of mevalonate and fluorinated mevalonates. PMID:25461893

  8. Synthesis of mevalonate- and fluorinated mevalonate prodrugs and their in vitro human plasma stability.

    PubMed

    Kang, Soosung; Watanabe, Mizuki; Jacobs, J C; Yamaguchi, Masaya; Dahesh, Samira; Nizet, Victor; Leyh, Thomas S; Silverman, Richard B

    2015-01-27

    The mevalonate pathway is essential for the production of many important molecules in lipid biosynthesis. Inhibition of this pathway is the mechanism of statin cholesterol-lowering drugs, as well as the target of drugs to treat osteoporosis, to combat parasites, and to inhibit tumor cell growth. Unlike the human mevalonate pathway, the bacterial pathway appears to be regulated by diphosphomevalonate (DPM). Enzymes in the mevalonate pathway act to produce isopentenyl diphosphate, the product of the DPM decarboxylase reaction, utilize phosphorylated (charged) intermediates, which are poorly bioavailable. It has been shown that fluorinated DPMs (6-fluoro- and 6,6,6-trifluoro-5-diphosphomevalonate) are excellent inhibitors of the bacterial pathway; however, highly charged DPM and analogs are not bioavailable. To increase cellular permeability of mevalonate analogs, we have synthesized various prodrugs of mevalonate and 6-fluoro- and 6,6,6-trifluoromevalonate that can be enzymatically transformed to the corresponding DPM or fluorinated DPM analogs by esterases or amidases. To probe the required stabilities as potentially bioavailable prodrugs, we measured the half-lives of esters, amides, carbonates, acetals, and ketal promoieties of mevalonate and the fluorinated mevalonate analogs in human blood plasma. Stability studies showed that the prodrugs are converted to the mevalonates in human plasma with a wide range of half-lives. These studies provide stability data for a variety of prodrug options having varying stabilities and should be very useful in the design of appropriate prodrugs of mevalonate and fluorinated mevalonates.

  9. Synthesis and Stability of a Nanoparticle-Infiltrated Solid OxideFuel Cell Electrode

    SciTech Connect

    Sholklapper, Tal Z.; Radmilovic, Velimir; Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

    2006-11-20

    Nanoparticulate catalysts infiltrated into SOFC (Solid OxideFUel Cell) electrodes can significantly enhance the cell performance, butthe stability of these electrodes has been an open issue. An infiltrationprocedure is reported that leads to a stable scandia-stablized zirconia(SSZ) cathode electrode performance.

  10. Torsion in box wings

    NASA Technical Reports Server (NTRS)

    Wheatley, John B

    1931-01-01

    Logical analysis of a box wing necessitates the allowance for the contribution of the drag spars to the torsional strength of the structure. A rigorous analysis is available in the use of the Method of Least Work. The best logical method of analysis is that applying Prandtl's Membrane Analogy. The results so obtained vary by a negligible amount from those obtained by the rigorous method.

  11. The Electronic Battle Box

    NASA Astrophysics Data System (ADS)

    Gouin, Denis; Turcotte, Guy; Lebel, Eric; Gilbert, Annie

    2000-08-01

    The Electronic Battle Box is an integrated suite of planning and decision-aid tools specially designed to facilitate Canadian Armed Force Officers during their training and during their tasks of preparing and conducting military operations. It is the result of a collaborative effort between the Defence Research Establishment Valcartier, the Directorate of Army Doctrine (DAD), the Directorate of Land Requirements (DLR), the G4 staff of 1Cdn Div HQ and CGI Information and Management Consultants Inc. Distributed on CD-ROM, the Electronic Battle Box contains efficient and user-friendly tools that significantly reduce the planning time for military operations and ensure staff officers a better focus on significant tasks. Among the tools are an OrBat Browser and an Equipment Browser allowing to view and edit military organizations, a Task Browser providing facilities to prepare plans using Gantt charts, a Logistic Planner allowing to estimate supply requirements applying complex calculations, and Road, Air and Rail Movement Planners. EBB also provides staff officers with a large set of doctrinal documents in an electronic format. This paper provides an overview of the various tools of the Electronic Battle Box.

  12. Profiles in garbage: Corrugated boxes

    SciTech Connect

    Miller, C.

    1997-12-01

    Corrugated boxes (also known as old corrugated containers, or OCC) are used to ship products to factories, warehouses, retail stores, offices, and homes. The primary market for OCC is the paperboard industry, which uses OCC for corrugated medium, linerboard, recycled paperboard, and other paper products. In addition, 2.6 million tons of OCC were exported in 1996. OCC provided 37% of the scrap paper that was exported in 1996. Some corrugated boxes can be reused before recycling. Corrugated boxes are easily and highly recyclable. Large producers such as grocery store warehouses and factories have recycled their corrugated boxes for some time. If shredded properly, uncoated corrugated boxes are easily compostable.

  13. Synthesis of Naphthylpyridines from Unsymmetrical Naphthylheptadiynes and the Configurational Stability of the Biaryl Axis.

    PubMed

    Fischer, Fabian; Siegle, Alexander F; Checinski, Marek; Fischer, Christine; Kral, Karolin; Thede, Richard; Trapp, Oliver; Hapke, Marko

    2016-04-15

    A series of different unsymmetrically substituted naphthyl-based diynes were synthesized. These substrates formed the foundation for the assembly of novel biaryls containing pyridine moieties with differently substituted five-membered rings in the backbone of the newly formed heterobiaryl system. The key step for their efficient construction was the photo- and cobalt-catalyzed [2 + 2 + 2] cycloaddition reaction between the corresponding naphthyldiyne and aceto- or benzonitrile. The heterobiaryl products have been isolated and investigated with respect to the configurational stability of their biaryl axis using dynamic chiral HPLC; subtle effects of the substitution pattern on the stability of the axis were observed. For several compounds the activation barriers (ΔG(‡)) of racemization were determined. Suitable substitution of the five-membered ring backbone exemplarily allowed the Co-catalyzed enantioselective cyclization to yield the enantiomerically enriched heterobiaryl. PMID:26999378

  14. Synthesis and thermal stability of selenium-doped hydroxyapatite with different substitutions

    NASA Astrophysics Data System (ADS)

    Liu, Yonghui; Ma, Jun; Zhang, Shengmin

    2015-12-01

    Selenium (Se) plays a specific role in human health, especially for its antitumor effect. Incorporation of selenium into biocompatible hydroxyapatite (HAP) may endow the materials with novel characteristics. In the current work, a series of seleniumdoped hydroxyapatite (Se-HAP) nanoparticles with different Se/P ratios were synthesized by a modified chemical precipitation. It was revealed that the powders with/without heattreatment were nano-sized needle-like HAP while the heat-treated samples have high crystallinity. The addition of selenium decreases the crystallinity of the synthesized apatite, and also takes a negative effect on the thermal stability of the as-prepared powders. The Se-HAP nanoparticles with Se/P molar ratio not more than 5% sintered at 900°C can achieve good crystallinity and thermal stability.

  15. Affinity separation in magnetically stabilized fluidized beds: synthesis and performance of packing materials

    SciTech Connect

    Lochmueller, C.H.; Wigman, L.S.

    1987-11-01

    A magnetically stabilized fluidized-bed separator designed to test the use of pellicular, ferromagnetic affinity chromatography packing materials has been developed. A wire wound solenoid was used to produce the magnetic field. The ferromagnetic packing material is comprised of a magnetite-containing, polyurethane gel coated onto polystyrene beads. The gel contains free carboxyl groups. These were carbodiimide-coupled to soy trypsin inhibitor and the material used for trypsin purification. Narrow-band affinity chromatography was carried out in packed-bed, fluidized-bed, and magnetically stabilized, fluidized-bed separators. Pressure drop, capacity, dilution, and peak asymmetry were evaluated for each type of separator. The three types provide comparable efficiency but the fluidized separators exhibit a much lower pressure drop. As might be expected, fluidized-bed separators perform well for affinity chromatography (large k') but poorly for size exclusion chromatography.

  16. Stability engineering of the Geobacillus stearothermophilus alcohol dehydrogenase and application for the synthesis of a polyamide 12 precursor.

    PubMed

    Kirmair, Ludwig; Seiler, Daniel Leonard; Skerra, Arne

    2015-12-01

    The thermostable NAD(+)-dependent alcohol dehydrogenase from Geobacillus stearothermophilus (BsADH) was exploited with regard to the biocatalytic synthesis of ω-oxo lauric acid methyl ester (OLAMe), a key intermediate for biobased polyamide 12 production, from the corresponding long-chain alcohol. Recombinant BsADH was produced in Escherichia coli as a homogeneous tetrameric enzyme and showed high activity towards the industrially relevant substrate ω-hydroxy lauric acid methyl ester (HLAMe) with K M = 86 μM and 44 U mg(-1). The equilibrium constant for HLAMe oxidation to the aldehyde (OLAMe) with NAD(+) was determined as 2.16 × 10(-3) from the kinetic parameters of the BsADH-catalyzed forward and reverse reactions. Since BsADH displayed limited stability under oxidizing conditions, the predominant oxidation-prone residue Cys257 was mutated to Leu based on sequence homology with related enzymes and computational simulation. This substitution resulted in an improved BsADH variant exhibiting prolonged stability and an elevated inactivation temperature. Semi-preparative biocatalysis at 60 °C using the stabilized enzyme, employing butyraldehyde for in situ cofactor regeneration with only catalytic amounts of NAD(+), yielded up to 23 % conversion of HLAMe to OLAMe after 30 min. In contrast to other oxidoreductases, no overoxidation to the dodecanoic diacid monomethyl ester was detected. Thus, the mutated BsADH offers a promising biocatalyst for the selective oxidation of fatty alcohols to yield intermediates for industrial polymer production.

  17. Stability engineering of the Geobacillus stearothermophilus alcohol dehydrogenase and application for the synthesis of a polyamide 12 precursor.

    PubMed

    Kirmair, Ludwig; Seiler, Daniel Leonard; Skerra, Arne

    2015-12-01

    The thermostable NAD(+)-dependent alcohol dehydrogenase from Geobacillus stearothermophilus (BsADH) was exploited with regard to the biocatalytic synthesis of ω-oxo lauric acid methyl ester (OLAMe), a key intermediate for biobased polyamide 12 production, from the corresponding long-chain alcohol. Recombinant BsADH was produced in Escherichia coli as a homogeneous tetrameric enzyme and showed high activity towards the industrially relevant substrate ω-hydroxy lauric acid methyl ester (HLAMe) with K M = 86 μM and 44 U mg(-1). The equilibrium constant for HLAMe oxidation to the aldehyde (OLAMe) with NAD(+) was determined as 2.16 × 10(-3) from the kinetic parameters of the BsADH-catalyzed forward and reverse reactions. Since BsADH displayed limited stability under oxidizing conditions, the predominant oxidation-prone residue Cys257 was mutated to Leu based on sequence homology with related enzymes and computational simulation. This substitution resulted in an improved BsADH variant exhibiting prolonged stability and an elevated inactivation temperature. Semi-preparative biocatalysis at 60 °C using the stabilized enzyme, employing butyraldehyde for in situ cofactor regeneration with only catalytic amounts of NAD(+), yielded up to 23 % conversion of HLAMe to OLAMe after 30 min. In contrast to other oxidoreductases, no overoxidation to the dodecanoic diacid monomethyl ester was detected. Thus, the mutated BsADH offers a promising biocatalyst for the selective oxidation of fatty alcohols to yield intermediates for industrial polymer production. PMID:26329849

  18. Synthesis of PVP-stabilized ruthenium colloids with low boiling point alcohols.

    PubMed

    Zhang, Yuqing; Yu, Jiulong; Niu, Haijun; Liu, Hanfan

    2007-09-15

    A route to the preparation of poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium colloids by refluxing ruthenium(III) chloride in low boiling point alcohols was developed. Deep purple colloids with shuttle-like ruthenium particles were also synthesized. XPS measurement verified the nanoparticles were in the metallic state. The morphology of metal nanoparticles was characterized by UV-visible absorption spectrophotometry, TEM and XRD.

  19. Synthesis and characterization of dendro-PLGA nanoconjugate for protein stabilization.

    PubMed

    Tiwari, Amit; Kesharwani, Prashant; Gajbhiye, Virendra; Jain, Narendra K

    2015-10-01

    The present investigation was aimed to develop the dendro-PLGA nanoconjugate (DPNC) for protection of insulin from degradation as well as its sustained release from nano-formulation. DPNC formulation was synthesized by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) coupling reaction and therapeutic efficacy of encapsulated protein (insulin) was measured by Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared spectroscopy (FTIR) and circular dichorism (CD) spectroscopy. We have also demonstrated the ability of DPNC formulation to prevent the native conformation of insulin within the system by comparing the amount of free protein with the protein extracted from this system. Stability study further revealed that as compared to free protein, DPNC formulation was more efficient to stabilize the protein. Additionally, in vivo data of protein loaded system in rats showed that DPNC formulation can able to maintain the native structure of insulin and hence retain therapeutic efficacy of protein. The novel dendro-PLGA nanoconjugate not only stabilize the insulin but also work as sustained release reservoir for insulin which reduces the frequency of dosage and side effect associate with denatured protein. PMID:26209778

  20. Synthesis and high content cell-based profiling of simplified analogues of the microtubule stabilizer (+)-discodermolide.

    PubMed

    Minguez, Jose M; Giuliano, Kenneth A; Balachandran, Raghavan; Madiraju, Charitha; Curran, Dennis P; Day, Billy W

    2002-12-01

    (+)-Discodermolide, a C24:4, trihydroxylated, octamethyl, carbamate-bearing fatty acid lactone originally isolated from a Caribbean sponge, has proven to be the most potent of the microtubule-stabilizing agents. Recent studies suggest that it or its analogues may have advantages over other classes of microtubule-stabilizing agents. (+)-Discodermolide's complex molecular architecture has made structure-activity relationship analysis in this class of compounds a formidable task. The goal of this study was to prepare simplified analogues of (+)-discodermolide and to analyze their biological activities to expand structure-activity relationships. A small library of analogues was prepared wherein the (+)-discodermolide methyl groups at C-14 and C-16 and the C-7 hydroxyl were removed, and the lactone was replaced by simple esters. The library components were analyzed for microtubule-stabilizing actions in vitro, antiproliferative activity against a small panel of human carcinoma cells, and cell signaling, microtubule architecture and mitotic spindle alterations by a multiparameter fluorescence cell-based screening technique. The results show that even drastic structural simplification can lead to analogues with actions related to microtubule targeting and signal transduction, but that these subtle effects were illuminated only through the high information content cell-based screen.

  1. Copper stabilization by zeolite synthesis in polluted soils treated with coal fly ash

    SciTech Connect

    Roberto Terzano; Matteo Spagnuolo; Luca Medici; Bart Vekemans; Laszlo Vincze; Koen Janssens; Pacifico Ruggiero

    2005-08-15

    This paper reports on the process of zeolite formation in an agricultural soil artificially polluted by high amounts of Cu (15 mg of Cu/g of soil dry weight) and treated with fused coal fly ash at 30 and 60 C and how this process affects the mobility and availability of the metal. As a consequence of the treatment, the amount of dissolved Cu, and thus its mobility, was strongly reduced, and the percentage of the metal stabilized in the solid phase increased over time, reaching values of 30% at 30{sup o}C and 40% at 60{sup o}C. The physicochemical phenomena responsible for Cu stabilization in the solid phase have been evaluated by EDTA sequential extractions and synchrotron radiation based X-ray microanalytical techniques. These techniques were used for the visualization of the spatial distribution and the speciation of Cu in and/or on the neo-formed zeolite particles. In particular, micro XRF (X-ray fluorescence) tomography showed direct evidence that Cu can be entrapped as clusters inside the porous zeolitic structures while -{mu}XANES (X-ray absorption near edge structure) spectroscopy determinations revealed Cu to be present mainly as Cu(II) hydroxide and Cu(II) oxide. The reported results could be useful as a basic knowledge for planning new technologies for the on-site physicochemical stabilization of heavy metals in heavily polluted soils. 32 refs., 5 figs.

  2. Synthesis and Stability of Ceramic-Carbonate Dual-Phase Membrane for Carbon Dioxide Separation

    NASA Astrophysics Data System (ADS)

    Norton, Tyler

    Of the potential technologies for pre-combustion capture, membranes offer the advantages of being temperature resistant, able to handle large flow rates, and having a relatively small footprint. A significant amount of research has centered on the use of polymeric and microporous inorganic membranes to separate CO2. These membranes, however, have limitations at high temperature resulting in poor permeation performance. To address these limitations, the use of a dense dual-phase membrane has been studied. These membranes are composed of conductive solid and conductive liquid phases that have the ability to selectively permeate CO2 by forming carbonate ions that diffuse through the membrane at high temperature. The driving force for transport through the membrane is a CO2 partial pressure gradient. The membrane provides a theoretically infinite selectivity. To address stability of the ceramic-carbonate dual-phase membrane for CO2 capture at high temperature, the ceramic phase of the membrane was studied and replaced with materials previously shown to be stable in harsh conditions. The permeation properties and stability of La0.6Sr0.4Co0.8Fe0.2O3-delta (LSCF)-carbonate, La0.85Ce0.1Ga0.3Fe0.65Al0.05O3-delta (LCGFA)-carbonate, and Ce0.8Sm0.2O1.9 (SDC)-carbonate membranes were examined under a wide range of experimental conditions at high temperature. LSCF-carbonate membranes were shown to be unstable without the presence of O2 due to reaction of CO2 with the ceramic phase. In the presence of O2, however, the membranes showed stable permeation behavior for more than one month at 900oC. LCGFA-carbonate membranes showed great chemical and permeation stability in the presence of various conditions including exposure to CH4 and H2, however, the permeation performance was quite low when compared to membranes in the literature. Finally, SDC-carbonate membranes showed great chemical and permeation stability both in a CO2:N2 environment for more than two weeks at 900oC as well

  3. Lewis Acid Zeolites for Biomass Conversion: Perspectives and Challenges on Reactivity, Synthesis, and Stability.

    PubMed

    Luo, Helen Y; Lewis, Jennifer D; Román-Leshkov, Yuriy

    2016-06-01

    Zeolites containing Sn, Ti, Zr, Hf, Nb, or Ta heteroatoms are versatile catalysts for the activation and conversion of oxygenated molecules owing to the unique Lewis acid character of their tetrahedral metal sites. Through fluoride-mediated synthesis, hydrophobic Lewis acid zeolites can behave as water-tolerant catalysts, which has resulted in a recent surge of experimental and computational studies in the field of biomass conversion. However, many open questions still surround these materials, especially relating to the nature of their active sites. This lack of fundamental understanding is exemplified by the many dissonant results that have been described in recent literature reports. In this review, we use a molecular-based approach to provide insight into the relationship between the structure of the metal center and its reactivity toward different substrates, with the ultimate goal of providing a robust framework to understand the properties that have the strongest influence on catalytic performance for the conversion of oxygenates. PMID:27146555

  4. Controlled synthesis of silver nanostructures stabilized by fluorescent polyarylene ether nitrile

    NASA Astrophysics Data System (ADS)

    Jia, Kun; Shou, Hongguo; Wang, Pan; Zhou, Xuefei; Liu, Xiaobo

    2016-07-01

    In this work, the intrinsically fluorescent polyarylene ether nitrile (PEN) was explored to realize the controlled synthesis of fluorescent silver nanostructures with different morphology for the first time. Specifically, it was found that silver nitrate (AgNO3) can be effectively reduced to silver nanoparticles using PEN as both reducing and surface capping agents in N, N-dimethylformamide (DMF). More interestingly, the morphology of obtained fluorescent silver nanostructures can be tuned from nanospheres to nanorods by simple variation of reaction time at 130 °C using a relative PEN:AgNO3 molar concentration ratio of 1:8. Meanwhile, the obtained Ag nanostructures exhibited both localized surface plasmon resonance (LSPR) band and fluorescent emission around 420 nm, which would find potential applications in biochemical sensing and optical devices fields.

  5. Synthesis, tribological and hydrolysis stability study of novel benzotriazole borate derivative.

    PubMed

    Liping, Xiong; Zhongyi, He; Liang, Qian; Lin, Mu; Aixi, Chen; Sheng, Han; Jianwei, Qiu; Xisheng, Fu

    2014-01-01

    Benzotriazole and borate derivatives have long been used as multifunctional additives to lubricants. A novel, environmentally friendly additive borate ester (NHB), which contains boron, ethanolamine, and benzotriazole groups in one molecule, was synthesized by a multi-step reaction, and its tribological properties in rapeseed oil (RSO) were investigated by a four-ball tribometer. The hydrolysis stability of the additive was investigated by half-time and open observation methods, and the mechanism of hydrolysis stability was discussed through Gaussian calculation. The novel compound NHB showed excellent performance under extreme pressure, against wearing, and in reducing friction, and its hydrolysis time is more than 1,220 times, which is better than that of triethyl borate. The mass ratio of NHB is bigger than that of the mixed liquid of triethyl borate and ethanolamine. The lone electron of amino N atoms forms a coordination effect with the B atom to compensate for the shortage of electrons in the B atom and to improve the hydrolysis stability of NHB. The surface morphology and the traces of different elements in the tribofilms formed with 1.0 wt.% NHB in were detected with scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy (EDX)and X-ray photoelectron spectroscopy(XPS). The results shown that the additive caused a tribochemical reaction with the steel ball surface during the lubricating process. A mixed boundary lubrication film that contains organic nitrogen and inorganic salts, such as BN, B2O3, FeOx, Fe-O-B, and FeB, was also formed, and the formation of the lubricating film improved the tribological properties of the base oil.

  6. Synthesis of highly emissive PIPES-stabilized gold nanoclusters and gold nanocluster-doped silica nanoparticles.

    PubMed

    Jang, Min Hoon; Pak, Joonsung; Yoo, Hyojong

    2013-04-01

    Stable and highly emissive gold nanoclusters were successfully synthesized by means of stabilization with PIPES (PIPES-Au NCs, where PIPES = 1,4-piperazinediethanesulfonic acid) using a thermal synthetic strategy. By varying the amount of PIPES, two Au NCs with different emission maxima were obtained. The synthesized Au NCs were successfully incorporated into a porous silica matrix to generate fluorescent PIPES-Au NC doped silica nanoparticles. Sequential doping of the PIPES-Au NCs with tetraethylorthosilicate (TEOS) and 3-(aminopropyl)triethoxysilane (APTS) furnished a silica matrix, which effectively protected the PIPES-Au NCs during repeated washing with polar solvent and the composite of which exhibited enhanced emission.

  7. Stabilization and targeting of INO80 to replication forks by BAP1 during normal DNA synthesis.

    PubMed

    Lee, Han-Sae; Lee, Shin-Ai; Hur, Shin-Kyoung; Seo, Jeong-Wook; Kwon, Jongbum

    2014-10-06

    The INO80 chromatin-remodelling complex has been implicated in DNA replication during stress in yeast. However, its role in normal DNA replication and its underlying mechanisms remain unclear. Here, we show that INO80 binds to replication forks and promotes fork progression in human cells under unperturbed, normal conditions. We find that Ino80, which encodes the catalytic ATPase of INO80, is essential for mouse embryonic DNA replication and development. Ino80 is recruited to replication forks through interaction with ubiquitinated H2A--aided by BRCA1-associated protein-1 (BAP1), a tumour suppressor and nuclear de-ubiquitinating enzyme that also functions to stabilize Ino80. Importantly, Ino80 is downregulated in BAP1-defective cancer cells due to the lack of an Ino80 stabilization mechanism via BAP1. Our results establish a role for INO80 in normal DNA replication and uncover a mechanism by which this remodeler is targeted to replication forks, suggesting a molecular basis for the tumour-suppressing function of BAP1.

  8. Synthesis, characterization and antimicrobial activity of dextran sulphate stabilized silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Cakić, Milorad; Glišić, Slobodan; Nikolić, Goran; Nikolić, Goran M.; Cakić, Katarina; Cvetinov, Miroslav

    2016-04-01

    Dextran sulphate stabilized silver nanoparticles (AgNPs - DS) were synthesized from aqueous solution of silver nitrate (AgNO3) and dextran sulphate sodium salt (DS). The characterization of AgNPs - DS was performed by ultraviolet-visible spectroscopy (UV-VIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and antimicrobial activity. The formation of AgNPs - DS was monitored by colour changes of the reaction mixture from yellowish to brown and by measuring the surface plasmon resonance absorption peak in UV-VIS spectra at 420 nm. The SEM analysis was used for size and shape determination of AgNPs - DS. The presence of elemental silver and its crystalline structure in AgNPs - DS were confirmed by EDX and XRD analyses. The possible functional groups of DS responsible for the reduction and stabilization of AgNPs were determinated by FTIR spectroscopy. The AgNPs - DS showed strong antibacterial activity against Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 11778, Bacillus luteus in haus strain, Bacillus subtilis ATTC 6633, Listeria monocytogenes ATCC 15313, Escherichia coli ATTC 25922, Pseudomonas aeruginosa ATTC 27853, Klebsiella pneumoniae ATTC 700603, Proteus vulgaris ATTC 8427, and antifungal activity against Candida albicans ATTC 2091.

  9. Vinyl monomers-induced synthesis of polyvinyl alcohol-stabilized selenium nanoparticles

    SciTech Connect

    Shah, Chetan P.; Singh, Krishan K.; Kumar, Manmohan; Bajaj, Parma N.

    2010-01-15

    A simple wet chemical method has been developed to synthesize selenium nanoparticles (size 100-200 nm), by reaction of sodium selenosulphate precursor with different vinyl monomers, such as acrylamide, N,N'-dimethylene bis acrylamide, methyl methacrylate, sodium acrylate, etc., in aqueous medium, under ambient conditions. Polyvinyl alcohol has been used to stabilize the selenium nanoparticles. Average size of the synthesized selenium nanoparticles can be controlled by adjusting concentration of both the precursors and the stabilizer. Rate of the reaction as well as size of the resultant selenium nanoparticles have been correlated with the functional groups of the different monomers. UV-vis optical absorption spectroscopy, X-ray diffraction, energy dispersive X-rays, differential scanning calorimetry, atomic force microscopy, scanning electron microscopy and transmission electron microscopy techniques have been employed to characterize the synthesized selenium nanoparticles. Gas chromatographic analysis of the reaction mixture established the non-catalytic role of the vinyl monomers, which were found to be consumed during the course of the reaction.

  10. Hydrothermal synthesis of platinum-group-metal nanoparticles by using HEPES as a reductant and stabilizer.

    PubMed

    So, Man-Ho; Ho, Chi-Ming; Chen, Rong; Che, Chi-Ming

    2010-06-01

    Platinum-group-metal (Ru, Os, Rh, Ir, Pd and Pt) nanoparticles are synthesized in an aqueous buffer solution of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (200 mM, pH 7.4) under hydrothermal conditions (180 degrees C). Monodispersed (monodispersity: 11-15%) metal nanoparticles were obtained with an average particle size of less than 5 nm (Ru: 1.8+/-0.2, Os: 1.6+/-0.2, Rh: 4.5+/-0.5, Ir: 2.0+/-0.3, Pd: 3.8+/-0.4, Pt: 1.9+/-0.2 nm). The size, monodispersity, and stability of the as-obtained metal nanoparticles were affected by the HEPES concentration, pH of the HEPES buffer solution, and reaction temperature. HEPES with two tertiary amines (piperazine groups) and terminal hydroxyl groups can act as a reductant and stabilizer. The HEPES molecules can bind to the surface of metal nanoparticles to prevent metal nanoparticles from aggregation. These platinum-group-metal nanoparticles could be deposited onto the surface of graphite, which catalyzed the aerobic oxidation of alcohols to aldehydes. PMID:20512785

  11. Small, Lightweight, Collapsible Glove Box

    NASA Technical Reports Server (NTRS)

    James, Jerry

    2009-01-01

    A small, lightweight, collapsible glove box enables its user to perform small experiments and other tasks. Originally intended for use aboard a space shuttle or the International Space Station (ISS), this glove box could also be attractive for use on Earth in settings in which work space or storage space is severely limited and, possibly, in which it is desirable to minimize weight. The development of this glove box was prompted by the findings that in the original space-shuttle or ISS setting, (1) it was necessary to perform small experiments in a large general-purpose work station, so that, in effect, they occupied excessive space; and it took excessive amounts of time to set up small experiments. The design of the glove box reflects the need to minimize the space occupied by experiments and the time needed to set up experiments, plus the requirement to limit the launch weight of the box and the space needed to store the box during transport into orbit. To prepare the glove box for use, the astronaut or other user has merely to insert hands through the two fabric glove ports in the side walls of the box and move two hinges to a locking vertical position (see figure). The user could do this while seated with the glove box on the user fs lap. When stowed, the glove box is flat and has approximately the thickness of two pieces of 8-in. (.20 cm) polycarbonate.

  12. Black box multigrid

    NASA Technical Reports Server (NTRS)

    Dendy, J. E., Jr.

    1981-01-01

    The black box multigrid (BOXMG) code, which only needs specification of the matrix problem for application in the multigrid method was investigated. It is contended that a major problem with the multigrid method is that each new grid configuration requires a major programming effort to develop a code that specifically handles that grid configuration. The SOR and ICCG methods only specify the matrix problem, no matter what the grid configuration. It is concluded that the BOXMG does everything else necessary to set up the auxiliary coarser problems to achieve a multigrid solution.

  13. Box H/ACA small ribonucleoproteins.

    PubMed

    Kiss, Tamás; Fayet-Lebaron, Eléonore; Jády, Beáta E

    2010-03-12

    Box H/ACA RNAs represent an abundant, evolutionarily conserved class of small noncoding RNAs. All H/ACA RNAs associate with a common set of proteins, and they function as ribonucleoprotein (RNP) enzymes mainly in the site-specific pseudouridylation of ribosomal RNAs (rRNAs) and small nuclear RNAs (snRNAs). Some H/ACA RNPs function in the nucleolytic processing of precursor rRNA (pre-rRNA) and synthesis of telomeric DNA. Thus, H/ACA RNPs are essential for three fundamental cellular processes: protein synthesis, mRNA splicing, and maintenance of genome integrity. Recently, great progress has been made toward understanding of the biogenesis, intracellular trafficking, structure, and function of H/ACA RNPs.

  14. One-step synthesis and stabilization of gold nanoparticles and multilayer film assembly

    SciTech Connect

    Bao Yayan; Bi Lihua; Wu Lixin

    2011-03-15

    Au nanoparticles (NPs) were synthesized in the one-pot procedure in water at room temperature with the wheel-shaped V{sup V}-V{sup IV} mixed-valence tungstovanadate [P{sub 8}W{sub 48}O{sub 184{l_brace}}V{sub 4}{sup V}V{sub 2}{sup IV}O{sub 12}(H{sub 2}O){sub 2{r_brace}2}]{sup 32-} (V12) acting as both reducing and stabilizing agents. The V12 stabilized Au NPs (Au-V12 NPs) were characterized by SEM, TEM, DLS, UV-vis spectroscopy, XPS, and XRD analyses and the negatively charged surface of the Au-V12 NPs was proved by the zeta potential analysis. Based on the layer-by-layer assembly (LbL), the Au-V12 NPs-containing multilayer films have been fabricated on ITO-coated glass slide and quartz substrates with poly(ethyleneimine) (PEI). The regular growth of the multilayer films was monitored by UV-vis spectroscopy and cyclic voltammetry, the composition was characterized by XPS. The Au-V12 NPs based composite films showed electrocatalytic activities towards the reduction of dioxygen and the oxidation of methanol. This approach is expected to open the way towards procedures aimed at the one-step fabrication of Au NPs and polyoxometalates (POMs) into the multilayer films. -- Graphical abstract: The wheel-shaped V{sup V}-V{sup IV} mixed-valence tungstovanadate [P{sub 8}W{sub 48}O{sub 184{l_brace}}V{sub 4}{sup V}V{sub 2}{sup IV}O{sub 12}(H{sub 2}O){sub 2{r_brace}2}]{sup 32-} (V12) stabilized Au nanoparticles (Au-V12 NPs) have been synthesized and characterized. The multilayer films containing Au-V12 NPs were fabricated and their electrocatalytic properties were studied. Display Omitted Research highlights: {yields} Au core-V12 shell nanostructures, Au-V12 NPs, were synthesized and characterized. {yields} The negatively charged Au NPs were fabricated and catalytic properties were studied. {yields} This study opens the way to the fabrication of multifunctional thin-film materials.

  15. Synthesis of Starch-Stabilized Ag Nanoparticles and Hg2+ Recognition in Aqueous Media

    NASA Astrophysics Data System (ADS)

    Fan, Yingju; Liu, Zhen; Wang, Le; Zhan, Jinhua

    2009-10-01

    The starch-stabilized Ag nanoparticles were successfully synthesized via a reduction approach and characterized with SPR UV/Vis spectroscopy, TEM, and HRTEM. By utilizing the redox reaction between Ag nanoparticles and Hg2+, and the resulted decrease in UV/Vis signal, we develop a colorimetric method for detection of Hg2+ ion. A linear relationship stands between the absorbance intensity of the Ag nanoparticles and the concentration of Hg2+ ion over the range from 10 ppb to 1 ppm at the absorption of 390 nm. The detection limit for Hg2+ ions in homogeneous aqueous solutions is estimated to be ~5 ppb. This system shows excellent selectivity for Hg2+ over other metal ions including Na+, K+, Ba2+, Mg2+, Ca2+, Fe3+, and Cd2+. The results shown herein have potential implications in the development of new colorimetric sensors for easy and selective detection and monitoring of mercuric ions in aqueous solutions.

  16. Cationic metal-corrole complexes: design, synthesis, and properties of guanine-quadruplex stabilizers.

    PubMed

    Fu, Boqiao; Zhang, Dan; Weng, Xiaocheng; Zhang, Ming; Ma, Heng; Ma, Yuzhi; Zhou, Xiang

    2008-01-01

    A series of pyridinium and quaternary ammonium copper corroles has been designed and synthesized. All new compounds have been fully characterized by NMR spectroscopy, high-resolution mass spectrometry, UV/Vis spectrscopy, and elemental analysis. Biochemical studies have indicated that all of these corrole derivatives can stabilize G-quadruplex structures, with corrole 4 being the most effective according to the results of circular dichroism (CD) melting experiments, polymerase chain reaction (PCR) stop assays, and surface plasmon resonance (SPR) experiments. Moreover, both corroles 3 and 4 tend to induce the human telomeric sequence to form hybrid G-quadruplex structures, whereas corroles 8 and 9 are more inclined to induce the human telomeric sequence to form antiparallel G-quadruplex structures.

  17. Synthesis and thermal stability of W-doped VO{sub 2} nanocrystals

    SciTech Connect

    Kong, F.Y.; Li, M.; Pan, S.S.; Zhang, Y.X.; Li, G.H.

    2011-11-15

    Highlights: {yields} The VO{sub 2} nanocrystals with a nearly spherical morphology with size ranging from 50 to 100 nm were synthesized by using V{sub 2}O{sub 5} and oxalic acid as precursors via a thermolysis method. {yields} The W dopant is in the W{sup 6+} form, and there is a small amount of V{sup 3+} in the VO{sub 2} nanocrystals. VO{sub 2} (R) nanocrystals with phase transition temperature at room temperature were obtained with 2.5 at% W-doing. {yields} A high stability upon heating-cooling cycles was observed with respect to MIT temperature, peak temperature and latent heat of the phase transition due to both the size effect and the existence of V{sup 3+} in the VO{sub 2} nanocrystals. -- Abstract: Pure and W-doped vanadium dioxide nanocrystals have been synthesized by using V{sub 2}O{sub 5} and oxalic acid as precursors via a thermolysis method. The VO{sub 2} nanocrystals have a nearly spherical morphology with size ranging from 50 to 100 nm. The metal-insulator transition (MIT) temperature of the nanocrystals decreases with increasing W-doping content. The successive heat-induced fatigue character of the MIT in W-doped VO{sub 2} nanocrystals was investigated by DSC analysis together with structural study, and a high stability upon heating-cooling cycles was found with respect to MIT temperature, peak temperature and latent heat of the phase transition.

  18. Projection optics box

    DOEpatents

    Hale, Layton C.; Malsbury, Terry; Hudyma, Russell M.; Parker, John M.

    2000-01-01

    A projection optics box or assembly for use in an optical assembly, such as in an extreme ultraviolet lithography (EUVL) system using 10-14 nm soft x-ray photons. The projection optics box utilizes a plurality of highly reflective optics or mirrors, each mounted on a precision actuator, and which reflects an optical image, such as from a mask, in the EUVL system onto a point of use, such as a target or silicon wafer, the mask, for example, receiving an optical signal from a source assembly, such as a developed from laser system, via a series of highly reflective mirrors of the EUVL system. The plurality of highly reflective optics or mirrors are mounted in a housing assembly comprised of a series of bulkheads having wall members secured together to form a unit construction of maximum rigidity. Due to the precision actuators, the mirrors must be positioned precisely and remotely in tip, tilt, and piston (three degrees of freedom), while also providing exact constraint.

  19. Synthesis and thermal stability of polycrystalline new divalent [beta][double prime]- and [beta]-ferrites prepared by ion exchange

    SciTech Connect

    Kalogirou, O. Aristotle Univ., Thessaloniki )

    1993-02-01

    Using ion-exchange chemistry the divalent cations Ba[sup 2+], Sr[sup 2+], Ca[sup 2+], Mg[sup 2+], Cd[sup 2+], Pb[sup 2+], Co[sup 2+], Zn[sup 2+], Mn[sup 2+], Fe[sup 2+], and Sn[sup 2+] have been substituted for K[sup +] in polycrystalline CdO-stabilized K-[beta][double prime]-ferrite samples. Ba, Sr, Ca, Mg, Pb, and Cd ion exchange led to the synthesis of new materials, the divalent M[sup 2+]-[beta][double prime]-ferrites (M = Ba, Sr, Ca, Mg) and M[sup 2+]-[beta]-ferrites (M = Cd, Pb), respectively. Co[sup 2+]-diffusion resulted in the formation of a spinel-type Co-ferrite. In the case of Zn, Mn, Fe, and Sn the samples decomposed to [alpha]-Fe[sub 2]O[sub 3]. The thermal stability of the new divalent [beta][double prime]- and [beta]-ferrites was studied either by high-temperature exchange reactions or by air annealing of the exchanged products. Ba- and Sr-[beta][double prime]-ferrites and Pb-[beta]-ferrite converted to M-type hexagonal ferrites with the magnetoplumbite structure, Mg-[beta][double prime]-ferrite decomposed to a spinel-type Mg-ferrite, and Ca-[beta][double prime]-ferrite and Cd-[beta]-ferrite decomposed to [alpha]-Fe[sub 2]O[sub 3]. Composition, lattice parameters, SEM photographs, and magnetic properties of the ferrites formed are given. The magnetic susceptibilities of the divalent [beta][double prime]- or [beta]-ferrites have values between 0.63 and 1.14 [times] 10[sup [minus]4] emu/g[center dot]Oe at room temperature. 41 refs., 1 fig., 4 tabs.

  20. Synthesis and structure characterization of Ru nanoparticles stabilized by PVP or {gamma}-Al{sub 2}O{sub 3}

    SciTech Connect

    Zawadzki, Miroslaw Okal, Janina

    2008-11-03

    Uniform and stable Ru nanoparticles were synthesized by reduction of RuCl{sub 3} in ethylene glycol (EG) in the presence of poly(N-vinyl-2-pyrrolidone) by using microwave-assisted solvothermal method. The obtained materials were characterized by UV-vis, FT-IR, XPS, XRD and TEM techniques, and used as precursors of heterogeneous metal colloid catalysts. Characterization by TEM showed that as-prepared PVP-stabilized Ru nanoparticles have small average diameters (below 2 nm) and narrow size distributions (1-3 nm). Diffraction data confirmed that a crystallite size is around 2.0 nm. A colloidal Ru/{gamma}-Al{sub 2}O{sub 3} catalyst was obtained by two different methods: immobilization of the PVP-stabilized Ru colloid on the support or by in situ deposition of Ru colloid, e.g., reduction of RuCl{sub 3} with EG in the presence of the {gamma}-alumina. It was found that both synthesis methods produced the Ru/{gamma}-Al{sub 2}O{sub 3} catalysts with narrow size distributions of metallic nanoparticles, that are distributed uniformly over the support. However, only in situ preparation of the colloidal Ru/{gamma}-Al{sub 2}O{sub 3} catalyst results in chlorine free system with high activity for hydrogen chemisorption. The H{sub 2} uptake on the Ru(PVP)/{gamma}-Al{sub 2}O{sub 3} catalyst was very low because the ruthenium surface was strongly occluded with a thin layer of polymer molecules.

  1. A LOW-COST PROCESS FOR THE SYNTHESIS OF NANOSIZE YTTRIA-STABILIZED ZIRCONIA (YSZ) BY MOLECULAR DECOMPOSITION

    SciTech Connect

    Anil V. Virkar

    2004-05-06

    This report summarizes the results of work done during the performance period on this project, between October 1, 2002 and December 31, 2003, with a three month no-cost extension. The principal objective of this work was to develop a low-cost process for the synthesis of sinterable, fine powder of YSZ. The process is based on molecular decomposition (MD) wherein very fine particles of YSZ are formed by: (1) Mixing raw materials in a powder form, (2) Synthesizing compound containing YSZ and a fugitive constituent by a conventional process, and (3) Selectively leaching (decomposing) the fugitive constituent, thus leaving behind insoluble YSZ of a very fine particle size. While there are many possible compounds, which can be used as precursors, the one selected for the present work was Y-doped Na{sub 2}ZrO{sub 3}, where the fugitive constituent is Na{sub 2}O. It can be readily demonstrated that the potential cost of the MD process for the synthesis of very fine (or nanosize) YSZ is considerably lower than the commonly used processes, namely chemical co-precipitation and combustion synthesis. Based on the materials cost alone, for a 100 kg batch, the cost of YSZ made by chemical co-precipitation is >$50/kg, while that of the MD process should be <$10/kg. Significant progress was made during the performance period on this project. The highlights of the progress are given here in a bullet form. (1) From the two selected precursors listed in Phase I proposal, namely Y-doped BaZrO{sub 3} and Y-doped Na{sub 2}ZrO{sub 3}, selection of Y-doped Na{sub 2}ZrO{sub 3} was made for the synthesis of nanosize (or fine) YSZ. This was based on the potential cost of the precursor, the need to use only water for leaching, and the short time required for the process. (2) For the synthesis of calcia-stabilized zirconia (CSZ), which has the potential for use in place of YSZ in the anode of SOFC, Ca-doped Na{sub 2}ZrO{sub 3} was demonstrated as a suitable precursor. (3) Synthesis of Y

  2. The Classroom Animal: Box Turtles.

    ERIC Educational Resources Information Center

    Kramer, David C.

    1986-01-01

    Provides basic information on the anatomy, physiology, behaviors, and distribution patterns of the box turtle. Offers suggestions for the turtle's care and maintenance in a classroom environment. (ML)

  3. Green synthesis of biogenic silver nanomaterials using Raphanus sativus extract, effects of stabilizers on the morphology, and their antimicrobial activities.

    PubMed

    Khan, Mohammad Naved; Khan, Tabrez Alam; Khan, Zaheer; Al-Thabaiti, Shaeel Ahmed

    2015-12-01

    The present study explores the reducing and capping potentials of aqueous Raphanus sativus root extract for the synthesis of silver nanomaterials for the first time in the absence and presence of two stabilizers, namely, water-soluble starch and cetyltrimethylammonium bromide (CTAB). The surface properties of silver nanoparticles (AgNPs) were determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), energy dispersion X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) techniques. The mean size of AgNPs, ranging from 3.2 to 6.0 nm, could be facilely controlled by merely varying the initial [extract], [CTAB], [starch], and [Ag(+)] ions. The agglomeration number, average number of silver atoms per nanoparticle, and changes in the fermi potentials were calculated and discussed. The AgNPs were evaluated for their antimicrobial activities against different pathogenic organisms. The inhibition action was due to the structural changes in the protein cell wall.

  4. Efficient assessment of modified nucleoside stability under conditions of automated oligonucleotide synthesis: characterization of the oxidation and oxidative desulfurization of 2-thiouridine.

    PubMed

    Sochacka, E

    2001-01-01

    In order to efficiently assess the chemical stability of modified nucleosides to the reagents and conditions of automated oligonucleotide synthesis, we designed, developed and tested a scheme in which the modified nucleoside, directly attached to a solid support, is exposed to the cyclic chemistry of the instrument. Stability of 2-thiouridine against different oxidizers was investigated. Tertbutyl hydroperoxide (1 M) in anhydrous acetonitrile was a more effective oxidizer for the incorporation of 2-thiouridine into oligonucleotide chains than the same oxidizer in methylene chloride. Carbon tetrachloride/water in the presence of a basic catalyst was superior in maintaining the thiocarbonyl function, but its utility for RNA synthesis has yet to be fully tested, whereas 2-phenylsulfonyloxaziridine was a very efficient reagent for oxidative desulfurization of 2-thiouridine. PMID:11720000

  5. Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds

    SciTech Connect

    McGregor, Donna; Burton-Pye, Benjamin P.; Lukens, Wayne W.; Howell, Robertha C.; Francesconi, Lynn C.

    2014-01-01

    Synthesis of technetium-99 (99Tc; t1/2: 2.1 105 years, max: 253 keV) materials is of importance in studies of the nuclear fuel cycle where Tc is a major fission product (6percent thermal yield from 235U and 239Pu), in understanding radioactive tank waste composition, and in identifying 99mTc compounds for nuclear medicine imaging. One of the most useful synthetic starting materials, (NBu4)TcOCl4, is susceptible to disproportionation in water to form TcO4 and TcIV species, especially TcO2 2H2O. This unwanted reaction is especially problematic when working with ligands bearing hard donor atoms, such as oxygen, where the stability with the soft TcV=O3+ core may be low. Polyoxometalates (POMs) are such ligands. They possess defect sites with four hard oxygen atoms and show low (ca. 108) stability constants with transition metals. Tc complexes of POMs are molecular-level models for Tc metal oxide solid-state materials and can provide information on coordination and redox environments of metal oxides that stabilize low-valent Tc. In order to synthesize pure Tc POM complexes [TcVO(1-P2W17O61)]7 (TcVO-1) and [TcVO(2-P2W17O61)]7 (TcVO-2) from (NBu4)TcOCl4, we have identified strategies that minimize formation of TcIV species and optimize the formation of pure TcV species. The parameters that we consider are the amount of ethylene glycol, which is employed as a transfer ligand to prevent hydrolysis of (NBu4)TcOCl4, and the precipitating agent. The TcIV species that contaminates the non-optimized syntheses is likely a TcIV -oxido-bridged dimer [TcIV-(-O)2-TcIV]. We also employ a novel procedure where the 2 ligand is photoactivated and reduced (in the presence of a sacrificial electron donor) to subsequently reduce TcVIIO4 to an isolatable TcVO-2 product that is remarkably free of TcIV.

  6. Mobility, Deposition and Remobilization of pre-Synthesis Stabilized Nano-scale Zero Valent Iron in Long Column Experiments

    NASA Astrophysics Data System (ADS)

    de Boer, C. V.; O'Carroll, D. M.; Sleep, B.

    2014-12-01

    Reactive zero-valent iron is currently being used for remediation of contaminated groundwater. Permeable reactive barriers are the current state-of-the-practice method for using zero-valent iron. Instead of an excavated trench filled with granular zero-valent iron, a relatively new and promising method is the injection of a nano-scale zero-valent iron colloid suspension (nZVI) into the subsurface using injection wells. One goal of nZVI injection can be to deposit zero valent iron in the aquifer and form a reactive permeable zone which is no longer bound to limited depths and plume treatment, but can also be used directly at the source. It is very important to have a good understanding of the transport behavior of nZVI during injection as well as the fate of nZVI after injection due to changes in the flow regime or water chemistry changes. So far transport was mainly tested using commercially available nZVI, however these studies suggest that further work is required as commercial nZVI was prone to aggregation, resulting in low physical stability of the suspension and very short travel distances in the subsurface. In the presented work, nZVI is stabilized during synthesis to significantly increase the physical suspension stability. To improve our understanding of nZVI transport, the feasibility for injection into various porous media materials and controlled deposition, a suite of column experiments are conducted. The column experiments are performed using a long 1.5m column and a novel nZVI measuring technique. The measuring technique was developed to non-destructively determine the concentration of nano-scale iron during the injection. It records the magnetic susceptibility, which makes it possible to get transient nZVI retention profiles along the column. These transient nZVI retention profiles of long columns provide unique insights in the transport behavior of nZVI which cannot be obtained using short columns or effluent breakthrough curves.

  7. Synthesis, Characterization, and Retinol Stabilization of Fatty Amide-β-cyclodextrin Conjugates.

    PubMed

    Kim, Hwanhee; Hu, Yiluo; Jeong, Daham; Jun, Bong-Hyun; Cho, Eunae; Jung, Seunho

    2016-01-01

    Amphiphilic cyclodextrin (CD) has been the object of growing scientific attention because of its two recognition sites, the cavity and the apolar heart, formed by self-assembly. In the present study, mono[6-deoxy-6-(octadecanamido)]-β-CD and mono[6-deoxy-6-(octadecenamido)]-β-CD were successfully synthesized by reacting mono-6-amino-6-deoxy-β-CD with N-hydroxysuccinimide esters of corresponding fatty acids in DMF. The structures were analyzed using nuclear magnetic resonance spectroscopy and mass spectrometry. The amphiphilic β-CDs were able to form self-assembled nano-vesicles in water, and the supramolecular architectures were characterized using fluorescence spectroscopy, dynamic light scattering, and transmission electron microscopy. Using the cavity-type nano-vesicles, all-trans-retinol was efficiently encapsulated; it was then stabilized against the photo-degradation. Therefore, the present fatty amide-β-CD conjugate will be a potential molecule for carrier systems in cosmetic and pharmaceutical applications. PMID:27455224

  8. Synthesis, characterization and antimicrobial activity of carboxymethyl dextrane stabilized silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Glišić, Slobodan; Cakić, Milorad; Nikolić, Goran; Danilović, Bojana

    2015-03-01

    Silver nanoparticles (AgNPs-CMD) were synthesized from aqueous solution of silver nitrate (AgNO3) and carboxymethyl dextrane (CMD) in mole ratio 1:1 and 1:2. The characterization of AgNPs-CMD was performed by ultraviolet-visible (UV-VIS) spectroscopy, gel permeation chromatography (GPC), scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and antimicrobial activity. The formation of AgNPs-CMD was screened by color changes of the reaction mixture to yellow, by measuring the surface plasmon resonance absorption peak in UV-VIS region at 420 nm. The GPC chromatography measurement confirmed the formation of AgNPs-CMD. The SEM microscopy was used for size and shape of AgNPs-CMD nanoparticles determination. The presence of elemental silver and crystalline structure of AgNPs-CMD were confirmed by XRD analyses. The possible functional group of CMD responsible for the reduction and stabilization of AgNPs were determinated by FT-IR spectroscopy. The AgNPs-CMD showed strong antibacterial activity against Bacillus lutea, Bacillus aureus, Bacillus cereus, Enterococus fecalis, Pseudomonas aeruginosa, Klebsiella pneumoniae and antifungal activity against Aspergillus spp., Penicillum spp., and Candida albicans.

  9. Green synthesis of pullulan stabilized gold nanoparticles for cancer targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Ganeshkumar, Moorthy; Ponrasu, Thangavel; Raja, Modhugoor Devendiran; Subamekala, Muthaiya Kannappan; Suguna, Lonchin

    2014-09-01

    The aim of this study was to synthesize green chemistry based gold nanoparticles using liver specific biopolymer and to develop a liver cancer targeted drug delivery system with enhanced efficacy and minimal side effects. Pullulan stabilized gold nanoparticles (PAuNPs) were coupled with 5-Fluorouracil (5-Fu) and folic acid (Fa) which could be used as a tool for targeted drug delivery and imaging of cancer. The toxicity of 5-Fu, 5-Fu adsorbed gold nanoparticles (5-Fu@AuNPs), Fa-coupled 5-Fu adsorbed gold nanoparticles (5-Fu@AuNPs-Fa), was studied using zebrafish embryo as an in vivo model. The in vitro cytotoxicity of free 5-Fu, 5-Fu@AuNPs, 5-Fu@AuNPs-Fa against HepG2 cells was studied and found that the amount of 5-Fu required to achieve 50% of growth of inhibition (Ic50) was much lower in 5-Fu@AuNP-Fa than in free 5-Fu, 5-Fu@AuNPs. The in vivo biodistribution of PAuNPs showed that higher amount of gold had been accumulated in liver (54.42 ± 5.96 μg) than in other organs.

  10. Shape-controlled synthesis of palladium and copper superlattice nanowires for high-stability hydrogen sensors.

    PubMed

    Yang, Dachi; Carpena-Núñez, Jennifer; Fonseca, Luis F; Biaggi-Labiosa, Azlin; Hunter, Gary W

    2014-01-20

    For hydrogen sensors built with pure Pd nanowires, the instabilities causing baseline drifting and temperature-driven sensing behavior are limiting factors when working within a wide temperature range. To enhance the material stability, we have developed superlattice-structured palladium and copper nanowires (PdCu NWs) with random-gapped, screw-threaded, and spiral shapes achieved by wet-chemical approaches. The microstructure of the PdCu NWs reveals novel superlattices composed of lattice groups structured by four-atomic layers of alternating Pd and Cu. Sensors built with these modified NWs show significantly reduced baseline drifting and lower critical temperature (259.4 K and 261 K depending on the PdCu structure) for the reverse sensing behavior than those with pure Pd NWs (287 K). Moreover, the response and recovery times of the PdCu NWs sensor were of ~9 and ~7 times faster than for Pd NWs sensors, respectively.

  11. Nonlinear optical materials: Synthesis, characterizations, thermal stability and electro-optical properties

    SciTech Connect

    Qiu Fengxian . E-mail: fxqiuchem@163.com; Xu Hongliang; Cao Yonglin; Jiang Yan; Zhou Yuming; Liu Juzheng; Zhang Xuping

    2007-03-15

    Two series of thermal stable polyimides and polyimide/silica hybrid materials have been synthesized. The silica content in the hybrid materials was varied from 0 to 22.5 wt.% and SiO{sub 2} phase was well dispersed in the polymer matrix. The glass transition temperature (T {sub g}) and the decomposition temperature (T {sub d}) were in the range 226-382 deg. C and 345-499 deg. C, respectively, for materials. The polymer solutions could be spin coated on the indium-tin-oxide (ITO) glass or other substrates to form optical quality thin films. The electro-optic coefficients ({gamma} {sub 33}) at the wavelength of 832 nm for polymer thin films poled were in the range of 12-25 pm/V and the values remained well (retained > 85% for more than 100 h). The heat capacities of some materials were in the range of 0.9755-1.1821 J K{sup -1} g{sup -1} for the temperature 273 and 363 K. No thermal anomaly was found in this temperature range. Most of them showed high thermal stability.

  12. Synthesis and antioxidant properties of chitosan and carboxymethyl chitosan-stabilized selenium nanoparticles.

    PubMed

    Chen, Wanwen; Li, Yanfang; Yang, Shuo; Yue, Lin; Jiang, Qixing; Xia, Wenshui

    2015-11-01

    Monodispersible selenium nanoparticles (SeNPs) were synthesized by using chitosan (CS) and carboxymethyl chitosan (CCS) as the stabilizer and capping agent using a facile synthetic approach. The structure, size, morphology and antioxidant activity of the nanocomposites were characterized by transmission electron microscopy (TEM), Ultraviolet-visible spectroscopy (UV-vis), Dynamic Light Scattering (DLS), Fourier transform infrared (FTIR), Thermogravimetric analysis (TGA). The results revealed that the monodispersible SeNPs (mean particle size of about 50 nm) were ligated with CS and CCS to form nanocomposites in aqueous solution for at least 30 days, and for 120 days the nanoparticles increased to 180 nm or so in size. The DPPH scavenging ability of CS-SeNPs was higher than that of CCS-SeNPs, and could reach 93.5% at a concentration of 0.6 mmol/L. Moreover, SeNPs, CS-SeNPs and CCS-SeNPs exhibited a higher ABTS scavenging ability in comparison to Na2SeO3.

  13. Hydrothermal synthesis of fine stabilized superparamagnetic nanoparticles of Zn2+ substituted manganese ferrite

    NASA Astrophysics Data System (ADS)

    Zahraei, Maryam; Monshi, Ahmad; Morales, Maria del Puerto; Shahbazi-Gahrouei, Daryoush; Amirnasr, Mehdi; Behdadfar, Behshid

    2015-11-01

    Superparamagnetic Zn2+ substituted manganese ferrite Mn1-xZnxFe2O4 (x=0.3, 0.35, 0.4 and 0.45) nanoparticles (NPs) were synthesized via a direct, efficient and environmental friendly hydrothermal method. The synthesized NPs were characterized by X-ray powder diffractometry (XRD), transmission electron microscopy (TEM), thermo-gravimetry (TG) and vibrating sample magnetometry (VSM). The effects of various parameters such as the pH of reaction mixture, time and temperature of hydrothermal treatment and Zn substitution on the spinel phase formation, the magnetization, and the size of resulting NPs are discussed. The Zn2+ substituted manganese ferrite NPs obtained from hydrothermal process crystallized mainly in the spinel phase. Nevertheless, without citrate ions, the hematite phase appeared in the product. The monophase Zn2+ substituted manganese ferrite NPs hydrothermally prepared in the presence of citric acid had mean particle size of 7 nm and a narrow size distribution. Furthermore, the synthesized NPs can be used to prepare ferrofluids for biomedical applications due to their small size, good stability in aqueous medium (pH 7) and also high magnetization value.

  14. Synthesis, processing and characterization of calcia-stabilized zirconia solid electrolytes for oxygen sensing applications

    SciTech Connect

    Zhou Minghua . E-mail: mzhou@nrcan.gc.ca; Ahmad, Aftab

    2006-04-13

    Precursor powders of calcia-stabilized zirconia (CSZ) solid electrolytes have been synthesized by a sol-gel method. The phase evolution of the precursor powders after thermal treatments at different temperatures were analysized by X-ray diffraction technique. Disc-shaped sensor elements were fabricated via uniaxial pressing of the calcined powders and subsequently sintered at 1650 deg. C. Scanning electron microscopy (SEM) was used to analyze the microstructure of the sintered pellets. Platinum electrodes were applied to the sintered elements to produce potentiometric/electrochemical gas sensors. The electrical response of the gas sensors to oxygen and the complex impedance of the sensors in air were measured at various temperatures. Impedance analyses indicate that the sensor cell with 15 mol% CaO has much lower resistance (the sum of bulk and grain-boundary resistance) than the sensor cell with 22 mol% CaO. This is also reflected by the EMF responses of both sensor cells to various oxygen concentrations in the testing gas. The EMF deviation from the theoretical value of the CSZ sensor cell with 22 mol% CaO was larger than that of the CSZ sensor cell with 15 mol% CaO. The corrrelations between material compositions, microstructures of the sintered pellets and the electrical properties of the sensors are discussed.

  15. Synthesis and antioxidant properties of chitosan and carboxymethyl chitosan-stabilized selenium nanoparticles.

    PubMed

    Chen, Wanwen; Li, Yanfang; Yang, Shuo; Yue, Lin; Jiang, Qixing; Xia, Wenshui

    2015-11-01

    Monodispersible selenium nanoparticles (SeNPs) were synthesized by using chitosan (CS) and carboxymethyl chitosan (CCS) as the stabilizer and capping agent using a facile synthetic approach. The structure, size, morphology and antioxidant activity of the nanocomposites were characterized by transmission electron microscopy (TEM), Ultraviolet-visible spectroscopy (UV-vis), Dynamic Light Scattering (DLS), Fourier transform infrared (FTIR), Thermogravimetric analysis (TGA). The results revealed that the monodispersible SeNPs (mean particle size of about 50 nm) were ligated with CS and CCS to form nanocomposites in aqueous solution for at least 30 days, and for 120 days the nanoparticles increased to 180 nm or so in size. The DPPH scavenging ability of CS-SeNPs was higher than that of CCS-SeNPs, and could reach 93.5% at a concentration of 0.6 mmol/L. Moreover, SeNPs, CS-SeNPs and CCS-SeNPs exhibited a higher ABTS scavenging ability in comparison to Na2SeO3. PMID:26256384

  16. 2. UPPER NOTTINGHAM MINE, WOODEN BOXES. BOXES ARE LOCATED APPROXIMATELY ...

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

    2. UPPER NOTTINGHAM MINE, WOODEN BOXES. BOXES ARE LOCATED APPROXIMATELY 10 YARDS TO THE RIGHT AND DOWNSLOPE OF THE ADIT IN ID-31-F-1. CAMERA IS POINTED EAST-SOUTHEAST. - Florida Mountain Mining Sites, Upper Nottingham Mine, West face of Florida Mountain, head of Jacobs Gulch, Silver City, Owyhee County, ID

  17. High-Temperature Stability of Cobalt Grafted on Low-Loading Incorporated Mo-MCM-41 Catalyst for Synthesis of Single-Walled Carbon Nanotubes

    SciTech Connect

    S Lee; C Zoican Loebick; L Pfefferle; G Haller

    2011-12-31

    Cobalt metal is a good catalyst for CO disproportionation to single-walled carbon nanotubes (SWNT) when particle size is stabilized on the nanometer scale. With reaction temperatures in the range of 973-1123 K, stabilization of nanometer Co particles against sintering requires a chemical bonding and/or occlusion of the Co particles. Catalysts with Co-grafted Mo-incorporated MCM-41 with different Mo loadings (<1 wt %) have been synthesized. Incorporation of Mo cations in the silica framework of MCM-41 provides different species as grafting sites. These grafting sites affect the strength of the metal-support interaction that controls sintering of active Co metal. The stability of Co at high temperature has been investigated by TPR and in situ/ex-situ X-ray absorption spectroscopy. The reduced Co metal particle size, after hydrogen prereduction, is independent of Mo loading. However, the Co particle size after SWNT synthesis is greatly affected by Mo anchoring and varied with loading. The Co particle size of low-Mo-loading samples after SWNT synthesis is little changed (from 0.88 nm after prereduction to 0.85 nm after SWNT synthesis), but the Co particle size difference of high-Mo-loading samples is gradually increased as the Mo loading is increased.

  18. ACYSYS in a box

    SciTech Connect

    Briegel, C.; Finstrom, D.; Hendricks, B.; King, C.; Lackey, S.; Neswold, R.; Nicklaus, D.; Patrick, J.; Petrov, A.; Rechenmacher, R.; Schumann, C.; /Fermilab

    2011-11-01

    The Accelerator Control System at Fermilab has evolved to enable this relatively large control system to be encapsulated into a 'box' such as a laptop. The goal was to provide a platform isolated from the 'online' control system. This platform can be used internally for making major upgrades and modifications without impacting operations. It also provides a standalone environment for research and development including a turnkey control system for collaborators. Over time, the code base running on Scientific Linux has enabled all the salient features of the Fermilab's control system to be captured in an off-the-shelf laptop. The anticipated additional benefits of packaging the system include improved maintenance, reliability, documentation, and future enhancements.

  19. Impedance Measurement Box

    ScienceCinema

    Christophersen, Jon

    2016-07-12

    Energy storage devices, primarily batteries, are now more important to consumers, industries and the military. With increasing technical complexity and higher user expectations, there is also a demand for highly accurate state-of-health battery assessment techniques. IMB incorporates patented, proprietary, and tested capabilities using control software and hardware that can be part of an embedded monitoring system. IMB directly measures the wideband impedance spectrum in seconds during battery operation with no significant impact on service life. It also can be applied to batteries prior to installation, confirming health before entering active service, as well as during regular maintenance. For more information about this project, visit http://www.inl.gov/rd100/2011/impedance-measurement-box/

  20. Impedance Measurement Box

    SciTech Connect

    Christophersen, Jon

    2011-01-01

    Energy storage devices, primarily batteries, are now more important to consumers, industries and the military. With increasing technical complexity and higher user expectations, there is also a demand for highly accurate state-of-health battery assessment techniques. IMB incorporates patented, proprietary, and tested capabilities using control software and hardware that can be part of an embedded monitoring system. IMB directly measures the wideband impedance spectrum in seconds during battery operation with no significant impact on service life. It also can be applied to batteries prior to installation, confirming health before entering active service, as well as during regular maintenance. For more information about this project, visit http://www.inl.gov/rd100/2011/impedance-measurement-box/

  1. Synthesis of Self-Assembled Multifunctional Nanocomposite Catalysts with Highly Stabilized Reactivity and Magnetic Recyclability

    NASA Astrophysics Data System (ADS)

    Yu, Xu; Cheng, Gong; Zheng, Si-Yang

    2016-05-01

    In this paper, a multifunctional Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite catalyst with highly stabilized reactivity and magnetic recyclability was synthesized by a self-assembled method. The magnetic Fe3O4 nanoparticles were coated with a thin layer of the SiO2 to obtain a negatively charged surface. Then positively charged poly(ethyleneimine) polymer (PEI) was self-assembled onto the Fe3O4@SiO2 by electrostatic interaction. Next, negatively charged glutathione capped gold nanoparticles (GSH-AuNPs) were electrostatically self-assembled onto the Fe3O4@SiO2@PEI. After that, silver was grown on the surface of the nanocomposite due to the reduction of the dopamine in the alkaline solution. An about 5 nm thick layer of polydopamine (PDA) was observed to form the Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite was carefully characterized by the SEM, TEM, FT-IR, XRD and so on. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite shows a high saturation magnetization (Ms) of 48.9 emu/g, which allows it to be attracted rapidly to a magnet. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite was used to catalyze the reduction of p-nitrophenol (4-NP) to p-aminophenol (4-AP) as a model system. The reaction kinetic constant k was measured to be about 0.56 min‑1 (R2 = 0.974). Furthermore, the as-prepared catalyst can be easily recovered and reused for 8 times, which didn’t show much decrease of the catalytic capability.

  2. Synthesis of Self-Assembled Multifunctional Nanocomposite Catalysts with Highly Stabilized Reactivity and Magnetic Recyclability

    PubMed Central

    Yu, Xu; Cheng, Gong; Zheng, Si-Yang

    2016-01-01

    In this paper, a multifunctional Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite catalyst with highly stabilized reactivity and magnetic recyclability was synthesized by a self-assembled method. The magnetic Fe3O4 nanoparticles were coated with a thin layer of the SiO2 to obtain a negatively charged surface. Then positively charged poly(ethyleneimine) polymer (PEI) was self-assembled onto the Fe3O4@SiO2 by electrostatic interaction. Next, negatively charged glutathione capped gold nanoparticles (GSH-AuNPs) were electrostatically self-assembled onto the Fe3O4@SiO2@PEI. After that, silver was grown on the surface of the nanocomposite due to the reduction of the dopamine in the alkaline solution. An about 5 nm thick layer of polydopamine (PDA) was observed to form the Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite was carefully characterized by the SEM, TEM, FT-IR, XRD and so on. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite shows a high saturation magnetization (Ms) of 48.9 emu/g, which allows it to be attracted rapidly to a magnet. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite was used to catalyze the reduction of p-nitrophenol (4-NP) to p-aminophenol (4-AP) as a model system. The reaction kinetic constant k was measured to be about 0.56 min−1 (R2 = 0.974). Furthermore, the as-prepared catalyst can be easily recovered and reused for 8 times, which didn’t show much decrease of the catalytic capability. PMID:27147586

  3. Selenoquinones stabilized by ruthenium(II) arene complexes: synthesis, structure, and cytotoxicity.

    PubMed

    Dubarle-Offner, Julien; Clavel, Catherine M; Gontard, Geoffrey; Dyson, Paul J; Amouri, Hani

    2014-05-01

    A new series of monoselenoquinone and diselenoquinone π complexes, [(η(6) -p-cymene)Ru(η(4) -C6 R4 SeE)] (R=H, E=Se (6); R=CH3 , E=Se (7); R=H, E=O (8)), as well as selenolate π complexes [(η(6) -p-cymene)Ru(η(5) -C6 H3 R2 Se)][SbF6 ] (R=H (9); R=CH3 (10)), stabilized by arene ruthenium moieties were prepared in good yields through nucleophilic substitution reactions from dichlorinated-arene and hydroxymonochlorinated-arene ruthenium complexes [(η(6) -p-cymene)Ru(C6 R4 XCl)][SbF6 ]2 (R=H, X=Cl (1); R=CH3 , X=Cl (2); R=H, X=OH (3)) as well as the monochlorinated π complexes [(η(6) -p-cymene)Ru(η(5) -C6 H3 R2 Cl)][SbF6 ]2 (R=H (4); R=CH3 (5)). The X-ray crystallographic structures of two of the compounds, [(η(6) -p-cymene)Ru(η(4) -C6 Me4 Se2 )] (7) and [(η(6) -p-cymene)Ru(η(4) -C6 H4 SeO)] (8), were determined. The structures confirm the identity of the target compounds and ascertain the coordination mode of these unprecedented ruthenium π complexes of selenoquinones. Furthermore, these new compounds display relevant cytotoxic properties towards human ovarian cancer cells.

  4. Synthesis of polycrystalline methane hydrate, and its phase stability and mechanical properties at elevated pressure

    USGS Publications Warehouse

    Stern, L.A.; Kirby, S.H.; Durham, W.B.

    1997-01-01

    Test specimens of methane hydrate were grown under static conditions by combining cold, pressurized CH4 gas with H2O ice grains, then warming the system to promote the reaction CH4 (g) + 6H2O (s???l) ??? CH4??6H2O. Hydrate formation evidently occurs at the nascent ice/liquid water interface, and complete reaction was achieved by warming the system above 271.5 K and up to 289 K, at 25-30 MPa, for approximately 8 hours. The resulting material is pure methane hydrate with controlled grain size and random texture. Fabrication conditions placed the H2O ice well above its melting temperature before reaction completed, yet samples and run records showed no evidence for bulk melting of the ice grains. Control experiments using Ne, a non-hydrate-forming gas, verified that under otherwise identical conditions, the pressure reduction and latent heat associated with ice melting is easily detectable in our fabrication apparatus. These results suggest that under hydrate-forming conditions, H2O ice can persist metastably at temperatures well above its melting point. Methane hydrate samples were then tested in constant-strain-rate deformation experiments at T= 140-200 K, Pc= 50-100 MPa, and ????= 10-4-10-6 s-1. Measurements in both the brittle and ductile fields showed that methane hydrate has measurably different strength than H2O ice, and work hardens to a higher degree compared to other ices as well as to most metals and ceramics at high homologous temperatures. This work hardening may be related to a changing stoichiometry under pressure during plastic deformation; x-ray analyses showed that methane hydrate undergoes a process of solid-state disproportionation or exsolution during deformation at conditions well within its conventional stability field.

  5. Cardboard Boxes: Learning Concepts Galore!

    ERIC Educational Resources Information Center

    Warner, Laverne; Wilmoth, Linda

    2007-01-01

    Mrs. Keenan, a preschool teacher, observed her 3-year-old granddaughter Riley pull, tug, and stack piles of holiday boxes on the floor. She remembered that her child care director had suggested using boxes as a curriculum theme, but she hadn't given much thought about the idea until now. She said to herself, "I wonder if my children would be as…

  6. What Makes a Better Box?

    ERIC Educational Resources Information Center

    Moyer, Richard; Everett, Susan

    2010-01-01

    Every morning, many Americans start their day with a bowl of cereal. Some spend time while they eat breakfast reading the back of the cereal box, but few consider its size, shape, and construction, or realize that it was designed by an engineer. This article describes a lesson in which students design, build, and critique cereal boxes. The lesson…

  7. Spirit Boxes: Expressions of Culture.

    ERIC Educational Resources Information Center

    DeMuro, Ted

    1984-01-01

    After studying the culture and art of the ancient civilizations of South America, Mesopotamia, Greece, and Egypt, secondary level art students made spirit boxes as expressions of the various cultures. How to make the boxes and how to prepare the face molds are described. (RM)

  8. Box-and-Whisker Plots.

    ERIC Educational Resources Information Center

    Larsen, Russell D.

    1985-01-01

    Box-and-whisker plots (which give rapid visualization of batches of data) can be effectively used to present diverse collections of data used in traditional first-year chemistry courses. Construction of box-and-whisker plots and their use with bond energy data and data on heats of formation and solution are discussed. (JN)

  9. Biopolymers from Composted Biowaste as Stabilizers for the Synthesis of Spherical and Homogeneously Sized Silver Nanoparticles for Textile Applications on Natural Fibers.

    PubMed

    Nisticò, Roberto; Barrasso, Marco; Carrillo Le Roux, Galo Antonio; Seckler, Marcelo Martins; Sousa, Walter; Malandrino, Mery; Magnacca, Giuliana

    2015-12-21

    The use of bio-based substances (BBS) obtained from composted biowaste as stabilizers for the production of silver nanoparticles (AgNPs) in substitution to citrate is investigated herein, evaluating the functionalization of natural fibers for textile antibacterial applications. The results obtained evidenced that BBS can substitute citrate as reducing/stabilizing agent in the synthesis, inducing a geometrical control (in shape and size) of the AgNPs. Two different substrates were selected (wool and cotton) and two dip-coating deposition techniques investigated. The release of AgNPs from the supports in water was evaluated under two different experimental conditions: 1) soaking (static conditions) for 7 and 15 days, simulating the contact with sweat, and 2) centrifugation (dynamic conditions), simulating a washing machine treatment. A wide physicochemical characterization was carried out to evaluate the effects of BBS on the morphology and stability of AgNPs suspensions as well as the functionalization effectiveness.

  10. Synthesis, molecular structure, and stability of a zirconocene derivative with α-Keggin mono-aluminum-substituted polyoxotungstate.

    PubMed

    Kato, Chika Nozaki; Makino, Yuki; Unno, Wataru; Uno, Hidemitsu

    2013-01-28

    The synthesis and crystal structure of a zirconocene derivative with α-Keggin mono-aluminum-substituted polyoxotungstate, [α-PW(11)Al(OH)O(39)ZrCp(2)](2)(6-) (Cp = C(5)H(5)(-)) (1), which was obtained by the reaction of α-Keggin mono-aluminum-substituted polyoxotungstate with a biscyclopentadienylzirconium(IV) complex, is described herein. Analytically pure, homogeneous, yellow crystals of the tetra-n-butylammonium salt of polyoxoanion 1, [(n-C(4)H(9))(4)N](6)[α-PW(11)Al(OH)O(39)ZrCp(2)](2) (TBA-1), were obtained from the ca. 1 : 1 reaction of [(n-C(4)H(9))(4)N](4)[α-PW(11){Al(OH(2))}O(39)] with Cp(2)Zr(OTf)(2)·THF (OTf = O(3)SCF(3)(-)) in acetonitrile solution under an argon atmosphere, followed by precipitation from water and crystallization from acetonitrile. TBA-1 was characterized based on X-ray structure analysis, elemental analysis, thermogravimetric/differential thermal analysis (TG/DTA), Fourier transform infrared (FTIR), and solution ((31)P, (27)Al, (19)F, (1)H, and (13)C) nuclear magnetic resonance (NMR) spectroscopy. Single-crystal X-ray structure analysis revealed that the two {PW(11)AlO(40)} units are bridged by two "bent sandwich" Cp(2)Zr(2+) fragments with C(2) symmetry. Each zirconium center was bound to a terminal oxygen atom of the aluminum and tungsten sites and an edge-sharing oxygen atom at the Al-O-W linkage. Further, the stability towards water was investigated by NMR ((31)P, (1)H, and (13)C) and FTIR spectroscopy. The η(5)-cyclopentadienylzirconium fragments were not eliminated from the surface of [α-PW(11){Al(OH(2))}O(39)](4-) even after 24 h exposure to 50 equiv. of water.

  11. Thinking Inside the Box

    SciTech Connect

    Boeheim, Charles T.; /SLAC

    2007-11-16

    In early 2007, SLAC was faced with a shortage of both electrical power and cooling in the main computer building, at the same time that the BaBar collaboration needed a new cluster of 250 batch machines installed. A number of different options were explored for the expansion. Provision of additional electrical power to the building was estimated to take one to two years, and cost several million dollars; additional cooling was even worse. Space in a Silicon Valley co-location facilities was reasonable on a one-year timescale, but broke even in costs by the end of three years, and were more expensive after that. There were also unresolved questions about the affects of additional latency from an offsite compute cluster to the onsite disk servers. The option of converting existing experimental hall space into computer space was estimated at one year, with uncertain availability. An option to aggressively replace several existing clusters with more power-efficient equipment was studied closely, but was disruptive to continued operations, expensive, and didn't provide any additional headroom. Finally, the installation of a Sun Project Blackbox (PBB) unit was selected as providing the capacity on a timescale of six months for a reasonable cost with minimal disruption to service. SLAC obtained and installed a beta unit and have been running it in production since September 2007. The experiences described are with the Early Access version of the PBB. The production version of the box has engineering changes based in part on our experiences.

  12. Posttranslational Control of ALA Synthesis Includes GluTR Degradation by Clp Protease and Stabilization by GluTR-Binding Protein1[OPEN

    PubMed Central

    Apitz, Janina; Nishimura, Kenji; Wolf, Anja; Hedtke, Boris

    2016-01-01

    5-Aminolevulinic acid (ALA) is the first committed substrate of tetrapyrrole biosynthesis and is formed from glutamyl-tRNA by two enzymatic steps. Glutamyl-tRNA reductase (GluTR) as the first enzyme of ALA synthesis is encoded by HEMA genes and tightly regulated at the transcriptional and posttranslational levels. Here, we show that the caseinolytic protease (Clp) substrate adaptor ClpS1 and the ClpC1 chaperone as well as the GluTR-binding protein (GBP) interact with the N terminus of GluTR. Loss-of function mutants of ClpR2 and ClpC1 proteins show increased GluTR stability, whereas absence of GBP results in decreased GluTR stability. Thus, the Clp protease system and GBP contribute to GluTR accumulation levels, and thereby the rate-limiting ALA synthesis. These findings are supported with Arabidopsis (Arabidopsis thaliana) hema1 mutants expressing a truncated GluTR lacking the 29 N-terminal amino acid residues of the mature protein. Accumulation of this truncated GluTR is higher in dark periods, resulting in increased protochlorophyllide content. It is proposed that the proteolytic activity of Clp protease counteracts GBP binding to assure the appropriate content of GluTR and the adequate ALA synthesis for chlorophyll and heme in higher plants. PMID:26884485

  13. Flexible bulb large storage box hydrogen maser

    NASA Technical Reports Server (NTRS)

    Reinhardt, V.

    1973-01-01

    The principal limitation on the accuracy of the hydrogen maser as a primary frequency standard has been the irreproducibility of the frequency shift caused by collisions of the radiating atoms with the walls of the vessel containing them. The flexible bulb-large storage box hydrogen maser allows correction for this wall shift within a single device, sidestepping the reproducibility problem, and reducing the frequency error from the wall shift to the level imposed by the device's stability. The principles of the device are discussed including the flexible bulb technique and the complications caused by a multiple region storage bulb. The stability of the device is discussed including a comparison with an ordinary hydrogen maser. Data is presented from a working flexible bulb-large storage box hydrogen maser demonstrating the feasibility of the device and showing some of its operating characteristics. The flexibility of the device is demonstrated by showing how the device's added degrees of freedom allow measurement of parameters unmeasurable in an ordinary hydrogen maser.

  14. Witting Reaction Using a Stabilized Phosphorus Ylid: An Efficient and Stereoselective Synthesis of Ethyl Trans-Cinnamate

    ERIC Educational Resources Information Center

    Speed, Traci J.; Mclntyre, Jean P.; Thamattoor, Dasan M.

    2004-01-01

    An instructive experiment for the synthesis of ethyl trans-cinnamate, a pleasant smelling ester used in perfumery and flavoring by the reaction of benzaldehyde with the stable ylid triphenylphosphorane is described. The synthesis, workup and characterization of trans-cinnamate may be accomplished in a single laboratory session with commonly…

  15. Poly(vinyl pyrrolidone): a dual functional reductant and stabilizer for the facile synthesis of noble metal nanoplates in aqueous solutions.

    PubMed

    Xiong, Yujie; Washio, Isao; Chen, Jingyi; Cai, Honggang; Li, Zhi-Yuan; Xia, Younan

    2006-09-26

    Poly(vinyl pyrrolidone) (PVP) has been extensively used in the solution-phase synthesis of many types of colloidal particles, where it is mainly considered as a steric stabilizer or capping agent with a major role to protect the product from agglomeration. In a recent study, we discovered that the hydroxyl end groups of PVP could also serve as a very mild reductant for kinetically controlled synthesis of Ag nanoplates with yields as high as 75%. Here we further demonstrate that hydroxyl-terminated PVP is also a well-suited reductant for the aqueous synthesis of circular, triangular, and hexagonal nanoplates made of other noble metals including Pd, Au, and Pt. The reduction kinetics of a metal salt by the hydroxyl end groups of PVP can be maneuvered in at least two different ways to facilitate the evolution of plate morphology: (i) by adjusting the molar ratio of PVP to the salt precursor and (ii) by altering the molecular weight of PVP. Unlike previously reported studies of Ag and Au thin plates, light was found to have a negligible role in the present synthesis. PMID:16981776

  16. Box truss development and applications

    NASA Astrophysics Data System (ADS)

    Coyner, J. V., Jr.

    1983-05-01

    The development and applications of a box truss design for large space antennas are discussed. A kinematic model with a mesh reflector was constructed. A prototype cube is described. Details of fabrication are given.

  17. Stabilization of AuNPs by monofunctional triazole linked to ferrocene, ferricenium, or coumarin and applications to synthesis, sensing, and catalysis.

    PubMed

    Li, Na; Zhao, Pengxiang; Igartua, María E; Rapakousiou, Amalia; Salmon, Lionel; Moya, Sergio; Ruiz, Jaime; Astruc, Didier

    2014-11-01

    Monofunctional triazoles linked to ferrocene, ferricenium, or coumarin (Cou), easily synthesized by copper-catalyzed azide alkyne (CuAAC) "click" reactions between the corresponding functional azides and (trimethylsilyl)acetylene followed by silyl group deprotection, provide a variety of convenient neutral ligands for the stabilization of functional gold nanoparticles (AuNPs) in polar organic solvents. These triazole (trz)-AuNPs are very useful toward a variety of applications to synthesis, sensing, and catalysis. Both ferrocenyl (Fc) and isostructural ferricenium linked triazoles give rise to AuNP stabilization, although by different synthetic routes. Indeed, the first direct synthesis and stabilization of AuNPs by ferricenium are obtained by the reduction of HAuCl4 upon reaction with a ferrocene derivative, AuNP stabilization resulting from a synergy between electrostatic and coordination effects. The ferricenium/ferrocene trz-AuNP redox couple is fully reversible, as shown by cyclic voltammograms that were recorded with both redox forms. These trz-AuNPs are stable for weeks in various polar solvents, but at the same time, the advantage of trz-AuNPs is the easy substitution of neutral trz ligands by thiols and other ligands, giving rise to applications. Indeed, this ligand substitution of trz at the AuNP surface yields a stable Fc-terminated nanogold-cored dendrimer upon reaction with a Fc-terminated thiol dendron, substitution of Cou-linked trz with cysteine, homocysteine, and glutathione provides remarkably efficient biothiol sensing, and a ferricenium-linked trz-AuNP catalyst is effective for NaBH4 reduction of 4-nitrophenol to 4-aminophenol. In this catalytic example, the additional electrostatic AuNP stabilization modulates the reaction rate and induction time.

  18. Stabilization of AuNPs by monofunctional triazole linked to ferrocene, ferricenium, or coumarin and applications to synthesis, sensing, and catalysis.

    PubMed

    Li, Na; Zhao, Pengxiang; Igartua, María E; Rapakousiou, Amalia; Salmon, Lionel; Moya, Sergio; Ruiz, Jaime; Astruc, Didier

    2014-11-01

    Monofunctional triazoles linked to ferrocene, ferricenium, or coumarin (Cou), easily synthesized by copper-catalyzed azide alkyne (CuAAC) "click" reactions between the corresponding functional azides and (trimethylsilyl)acetylene followed by silyl group deprotection, provide a variety of convenient neutral ligands for the stabilization of functional gold nanoparticles (AuNPs) in polar organic solvents. These triazole (trz)-AuNPs are very useful toward a variety of applications to synthesis, sensing, and catalysis. Both ferrocenyl (Fc) and isostructural ferricenium linked triazoles give rise to AuNP stabilization, although by different synthetic routes. Indeed, the first direct synthesis and stabilization of AuNPs by ferricenium are obtained by the reduction of HAuCl4 upon reaction with a ferrocene derivative, AuNP stabilization resulting from a synergy between electrostatic and coordination effects. The ferricenium/ferrocene trz-AuNP redox couple is fully reversible, as shown by cyclic voltammograms that were recorded with both redox forms. These trz-AuNPs are stable for weeks in various polar solvents, but at the same time, the advantage of trz-AuNPs is the easy substitution of neutral trz ligands by thiols and other ligands, giving rise to applications. Indeed, this ligand substitution of trz at the AuNP surface yields a stable Fc-terminated nanogold-cored dendrimer upon reaction with a Fc-terminated thiol dendron, substitution of Cou-linked trz with cysteine, homocysteine, and glutathione provides remarkably efficient biothiol sensing, and a ferricenium-linked trz-AuNP catalyst is effective for NaBH4 reduction of 4-nitrophenol to 4-aminophenol. In this catalytic example, the additional electrostatic AuNP stabilization modulates the reaction rate and induction time. PMID:25363304

  19. The lithium vapor box divertor

    NASA Astrophysics Data System (ADS)

    Goldston, R. J.; Myers, R.; Schwartz, J.

    2016-02-01

    It has long been recognized that volumetric dissipation of the plasma heat flux from a fusion power system is preferable to its localized impingement on a material surface. Volumetric dissipation mitigates both the anticipated very high heat flux and intense particle-induced damage due to sputtering. Recent projections to a tokamak demonstration power plant suggest an immense upstream parallel heat flux, of order 20 GW m-2, implying that fully detached operation may be a requirement for the success of fusion power. Building on pioneering work on the use of lithium by Nagayama et al and by Ono et al as well as earlier work on the gas box divertor by Watkins and Rebut, we present here a concept for a lithium vapor box divertor, in which lithium vapor extracts momentum and energy from a fusion-power-plant divertor plasma, using fully volumetric processes. At the high powers and pressures that are projected this requires a high density of lithium vapor, which must be isolated from the main plasma in order to avoid lithium build-up on the chamber walls or in the plasma. Isolation is achieved through a powerful multi-box differential pumping scheme available only for condensable vapors. The preliminary box-wise calculations are encouraging, but much more work is required to demonstrate the practical viability of this scheme, taking into account at least 2D plasma and vapor flows within and between the vapor boxes and out of the vapor boxes to the main plasma.

  20. Experimental determination of the elastic cotunneling rate in a hybrid single-electron box

    SciTech Connect

    Sun, Chia-Heng; Tai, Po-Chen; Chen, Yung-Fu; Jiang, Jheng-An; Wu, Cen-Shawn; Chen, Jeng-Chung

    2014-06-09

    We report measurements of charge configurations and charge transfer dynamics in a hybrid single-electron box composed of aluminum and copper. We used two single-electron transistors (SETs) to simultaneously read out different parts of the box, enabling us to map out stability diagrams of the box and identify various charge transfer processes in the box. We further characterized the elastic cotunneling in the box, which is an important source of error in electron turnstiles consisting of hybrid SETs, and found that the rate was as low as 1 Hz at degeneracy and compatible with theoretical estimates for electron tunneling via virtual states in the central superconducting island of the box.

  1. Mesoporous Silica Nanoparticle-Stabilized and Manganese-Modified Rhodium Nanoparticles as Catalysts for Highly Selective Synthesis of Ethanol and Acetaldehyde from Syngas

    SciTech Connect

    Huang, Yulin; Deng, Weihua; Guo, Enruo; Chung, Po-Wen; Chen, Senniang; Trewyn, Brian; Brown, Robert; Lin, Victor

    2012-03-30

    Well-defined and monodispersed rhodium nanoparticles as small as approximately 2 nm were encapsulated in situ and stabilized in a mesoporous silica nanoparticle (MSN) framework during the synthesis of the mesoporous material. Although both the activity and selectivity of MSN-encapsulated rhodium nanoparticles in CO hydrogenation could be improved by the addition of manganese oxide as expected, the carbon selectivity for C2 oxygenates (including ethanol and acetaldehyde) was unprecedentedly high at 74.5 % with a very small amount of methanol produced if rhodium nanoparticles were modified by manganese oxide with very close interaction.

  2. 30 CFR 57.12006 - Distribution boxes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distribution boxes. 57.12006 Section 57.12006... and Underground § 57.12006 Distribution boxes. Distribution boxes shall be provided with a... deenergized, and the distribution box shall be labeled to show which circuit each device controls....

  3. 30 CFR 57.12006 - Distribution boxes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Distribution boxes. 57.12006 Section 57.12006... and Underground § 57.12006 Distribution boxes. Distribution boxes shall be provided with a... deenergized, and the distribution box shall be labeled to show which circuit each device controls....

  4. 30 CFR 57.12006 - Distribution boxes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Distribution boxes. 57.12006 Section 57.12006... and Underground § 57.12006 Distribution boxes. Distribution boxes shall be provided with a... deenergized, and the distribution box shall be labeled to show which circuit each device controls....

  5. Plate forming and break down pizza box

    DOEpatents

    Pantisano, Frank; Devine, Scott M.

    1992-01-01

    A standard corrugated paper pizza box is provided with slit cuts cut through the top panel of the pizza box in a shape to form four circular serving plates with a beveled raised edge and cross slit cuts through the bottom panel of the pizza box separating the box into four essentially equal portions for easy disposal.

  6. Unsymmetrical Aryl(2,4,6-trimethoxyphenyl)iodonium Salts: One-Pot Synthesis, Scope, Stability, and Synthetic Studies.

    PubMed

    Seidl, Thomas L; Sundalam, Sunil K; McCullough, Brennen; Stuart, David R

    2016-03-01

    Diaryliodonium salts have recently attracted significant attention as metal-free-arylation reagents in organic synthesis, and efficient access to these salts is critical for advancement of their use in reaction discovery and development. The trimethoxybenzene-derived auxiliary is a promising component of unsymmetrical variants, yet access remains limited. Here, a one-pot synthesis of aryl(2,4,6-trimethoxyphenyl)iodonium salts from aryl iodides, m-CPBA, p-toluenesulfonic acid, and trimethoxybenzene is described. Optimization of the reaction conditions for this one-pot synthesis was enabled by the method of multivariate analysis. The reaction is fast (<1 h), provides a high yield of product (>85% average), and has broad substrate scope (>25 examples) including elaborate aryl iodides. The utility of these reagents is demonstrated in moderate to high yielding arylation reactions with C-, N-, O-, and S-nucleophiles including the synthesis of a liquid crystal molecule.

  7. Effects of Gold Salt Speciation and Structure of Human and Bovine Serum Albumin on the Synthesis and Stability of Gold Nanostructures

    NASA Astrophysics Data System (ADS)

    Miranda, Érica; Tofanello, Aryane; Brito, Adrianne; Lopes, David; Giacomelli, Fernando; Albuquerque, Lindomar; Costa, Fanny; Ferreira, Fabio; Araujo-Chaves, Juliana; de Castro, Carlos; Nantes, Iseli

    2016-03-01

    with the gold surface. Therefore, the cysteine side chain of albumins is important for the colloidal stabilization of GNPs rather than as the reducing agent for the synthesis. Despite the presence of more reactive gold species at more acidic pH values, i.e., below

  8. Box graphs and resolutions I

    NASA Astrophysics Data System (ADS)

    Braun, Andreas P.; Schäfer-Nameki, Sakura

    2016-04-01

    Box graphs succinctly and comprehensively characterize singular fibers of elliptic fibrations in codimension two and three, as well as flop transitions connecting these, in terms of representation theoretic data. We develop a framework that provides a systematic map between a box graph and a crepant algebraic resolution of the singular elliptic fibration, thus allowing an explicit construction of the fibers from a singular Weierstrass or Tate model. The key tool is what we call a fiber face diagram, which shows the relevant information of a (partial) toric triangulation and allows the inclusion of more general algebraic blowups. We shown that each such diagram defines a sequence of weighted algebraic blowups, thus providing a realization of the fiber defined by the box graph in terms of an explicit resolution. We show this correspondence explicitly for the case of SU (5) by providing a map between box graphs and fiber faces, and thereby a sequence of algebraic resolutions of the Tate model, which realizes each of the box graphs.

  9. Aminolysis of polyethylene terephthalate surface along with in situ synthesis and stabilizing ZnO nanoparticles using triethanolamine optimized with response surface methodology.

    PubMed

    Poortavasoly, Hajar; Montazer, Majid; Harifi, Tina

    2016-01-01

    This research concerned the simultaneous polyester surface modification and synthesis of zinc oxide nano-reactors to develop durable photo-bio-active fabric with variable hydrophobicity/hydrophilicity under sunlight. For this purpose, triethanolamine (TEA) was applied as a stabilizer and pH adjusting chemical for the aminolysis of polyester surface and enhancing the surface reactivity along with synthesis and deposition of ZnO nanoparticles on the fabric. Therefore, TEA played a crucial role in providing the alkaline condition for the preparation of zinc oxide nanoparticles and acting as stabilizer controlling the size of the prepared nanoparticles. The stain-photodegradability regarded as self-cleaning efficiency, wettability and weight change under the process was optimized based on zinc acetate and TEA concentrations, using central composite design (CCD). Findings also suggested the potential of the prepared fabric in inhibiting Staphylococcus aureus and Escherichia coli bacteria growth with greater than 99.99% antibacterial efficiency. Besides, the proposed treatment had no detrimental effect on tensile strength and hand feeling of the polyester fabric.

  10. Aminolysis of polyethylene terephthalate surface along with in situ synthesis and stabilizing ZnO nanoparticles using triethanolamine optimized with response surface methodology.

    PubMed

    Poortavasoly, Hajar; Montazer, Majid; Harifi, Tina

    2016-01-01

    This research concerned the simultaneous polyester surface modification and synthesis of zinc oxide nano-reactors to develop durable photo-bio-active fabric with variable hydrophobicity/hydrophilicity under sunlight. For this purpose, triethanolamine (TEA) was applied as a stabilizer and pH adjusting chemical for the aminolysis of polyester surface and enhancing the surface reactivity along with synthesis and deposition of ZnO nanoparticles on the fabric. Therefore, TEA played a crucial role in providing the alkaline condition for the preparation of zinc oxide nanoparticles and acting as stabilizer controlling the size of the prepared nanoparticles. The stain-photodegradability regarded as self-cleaning efficiency, wettability and weight change under the process was optimized based on zinc acetate and TEA concentrations, using central composite design (CCD). Findings also suggested the potential of the prepared fabric in inhibiting Staphylococcus aureus and Escherichia coli bacteria growth with greater than 99.99% antibacterial efficiency. Besides, the proposed treatment had no detrimental effect on tensile strength and hand feeling of the polyester fabric. PMID:26478337

  11. Effects of Dopant Metal Variation and Material Synthesis Method on the Material Properties of Mixed Metal Ferrites in Yttria Stabilized Zirconia for Solar Thermochemical Fuel Production

    DOE PAGES

    Leonard, Jeffrey; Reyes, Nichole; Allen, Kyle M.; Randhir, Kelvin; Li, Like; AuYeung, Nick; Grunewald, Jeremy; Rhodes, Nathan; Bobek, Michael; Klausner, James F.

    2015-01-01

    Mixed metal ferrites have shown much promise in two-step solar-thermochemical fuel production. Previous work has typically focused on evaluating a particular metal ferrite produced by a particular synthesis process, which makes comparisons between studies performed by independent researchers difficult. A comparative study was undertaken to explore the effects different synthesis methods have on the performance of a particular material during redox cycling using thermogravimetry. This study revealed that materials made via wet chemistry methods and extended periods of high temperature calcination yield better redox performance. Differences in redox performance between materials made via wet chemistry methods were minimal andmore » these demonstrated much better performance than those synthesized via the solid state method. Subsequently, various metal ferrite samples (NiFe 2 O 4 , MgFe 2 O 4 , CoFe 2 O 4 , and MnFe 2 O 4 ) in yttria stabilized zirconia (8YSZ) were synthesized via coprecipitation and tested to determine the most promising metal ferrite combination. It was determined that 10 wt.% CoFe 2 O 4 in 8YSZ produced the highest and most consistent yields of O 2 and CO. By testing the effects of synthesis methods and dopants in a consistent fashion, those aspects of ferrite preparation which are most significant can be revealed. More importantly, these insights can guide future efforts in developing the next generation of thermochemical fuel production materials.« less

  12. Asymptotic symmetries from finite boxes

    NASA Astrophysics Data System (ADS)

    Andrade, Tomás; Marolf, Donald

    2016-01-01

    It is natural to regulate an infinite-sized system by imposing a boundary condition at finite distance, placing the system in a 'box.' This breaks symmetries, though the breaking is small when the box is large. One should thus be able to obtain the asymptotic symmetries of the infinite system by studying regulated systems. We provide concrete examples in the context of Einstein-Hilbert gravity (with negative or zero cosmological constant) by showing in 4 or more dimensions how the anti-de Sitter and Poincaré asymptotic symmetries can be extracted from gravity in a spherical box with Dirichlet boundary conditions. In 2 + 1 dimensions we obtain the full double-Virasoro algebra of asymptotic symmetries for AdS3 and, correspondingly, the full Bondi-Metzner-Sachs (BMS) algebra for asymptotically flat space. In higher dimensions, a related approach may continue to be useful for constructing a good asymptotically flat phase space with BMS asymptotic symmetries.

  13. Influence of stabilizing agent and synthesis temperature on the optical properties of silver nanoparticles as active materials in surface plasmon resonance (SPR) biosensor

    NASA Astrophysics Data System (ADS)

    Mahmudin, Lufsyi; Suharyadi, Edi; Utomo, Agung Bambang Setio; Abraha, Kamsul

    2016-04-01

    It has been successfully carried out the synthesis of colloidal silver nanoparticles by chemical reduction method. Silver nitrate (AgNO3) was used as metal precursors and trisodium citrate as the reducing agent. In the synthesis process, were varied the stabilizing agent of Polyvinyl Alcohol (PVA) and polyvinylpyrrolidone (PVP) and heating temperature. The formation of silver nanoparticles was observed visually with discoloration (yellowish). The formation and the structure of silver nanoparticles in colloidal solution were further examined through their optical properties by using a UV-Vis spectrometer. The wavelength absorption spectrum of colloidal silver nanoparticles shows that maximum surface plasmon absorption for the trisodium citrate-synthesized nanoparticles was at 429.43 nm for temperature of 90°C. The addition of the stabilizer sharpened spectrum curves and caused red shift in the maximum absorption peak of 429.01 nm and 427.09 nm for PVA and PVP respectively. Meanwhile, the addition of the synthesis temperature also sharpened the maximum surface plasmon absorption band and the red shift the maximum absorption peak of 428.79 nm and 428.58 nm for temperature of 110°C and 120°C respectively. Red shift of the maximum absorption peak indicates a smaller particle size. The maximum surface plasmon absorption band in the range of 427.09 nm to 429.43 nm indicates the presence of spherical or roughly spherical silver nanoparticles and TEM imaging confirmed this shape. TEM imaging results show that the diameter size of the silver nanoparticles range of 10 nm to 60 nm as well as the morphology (crystallites) of silver nanoparticles have spherical geometry with particle distribution which quite dispersive. The dispersibility of nanoparticles such as this could potentially be used as an active material of SPR biosensor.

  14. (Lysozyme type VI)-stabilized Au8 clusters: synthesis mechanism and application for sensing of glutathione in a single drop of blood.

    PubMed

    Chen, Tzu-Heng; Tseng, Wei-Lung

    2012-06-25

    This paper presents a one-pot approach for preparing highly fluorescent Au(8) clusters by reacting the Au(3+) precursor solution with lysozyme type VI (Lys VI) at pH 3. The fluorescence band of (Lys VI)-stabilized Au(8) clusters is centered at 455 nm on the excitation at 380 nm. Blue-emitting Au(8) clusters have a high quantum yield (∼56%), two fluorescence lifetimes, and a rare amount of Au(+) on the surface of the Au core. When the pH of a solution of Au(8) clusters increases suddenly to 12, the Au(8) clusters gradually convert to Au(25) clusters over time. This conversion is also observed in the case of (Lys VI)-directed synthesis of Au(25) clusters at pH 12. The pH-induced conversion of Au(8) to Au(25) clusters suggests that the size of (Lys VI)-stabilized gold nanoclusters (AuNCs) relies on the secondary structure of Lys VI, which is susceptible to pH change. Based on these results and previous literature, this paper proposes the possible mechanism for growing (Lys VI)-stabilized Au(8) and Au(25) clusters. Additionally, (Lys VI)-stabilized Au(8) clusters could sense glutathione (GSH) through GSH-induced core-etching of Au(8) clusters; the limit of detection at a signal-to-noise ratio of 3 for GSH is determined to be 20 nm. Except for cysteine, the selectivity of (Lys VI)-stabilized Au(8) clusters for GSH over amino acids is remarkably high. The practicality of using Au(8) clusters to determine the concentration of GSH in a single drop of blood is also validated.

  15. NETL's JIC in a box

    ScienceCinema

    David Anna

    2016-07-12

    The National Energy Technology Laboratory developed the idea of a portable joint information center AKA JIC in-a-box. This video discribes some of the equipment in the portable JIC as well as some of the methodology that NETL developed as a result of this portable JIC concept.

  16. The Cereal Box Problem Revisited.

    ERIC Educational Resources Information Center

    Wilkins, Jesse L. M.

    1999-01-01

    Investigates the cereal box problem using both an experimental and theoretical framework, and Monte Carlo methods. Using empirical data, students can discover patterns and relationships that help them understand the origin of the theoretical solution to the problem. Contains 17 references. (Author/ASK)

  17. NETL's JIC in a box

    SciTech Connect

    David Anna

    2009-06-03

    The National Energy Technology Laboratory developed the idea of a portable joint information center AKA JIC in-a-box. This video discribes some of the equipment in the portable JIC as well as some of the methodology that NETL developed as a result of this portable JIC concept.

  18. Black Boxes in Workplace Mathematics

    ERIC Educational Resources Information Center

    Williams, Julian; Wake, Geoff

    2007-01-01

    We ground Cultural-Historical Activity Theory (CHAT) in studies of workplace practices from a mathematical point of view. We draw on multiple case study visits by college students and teacher-researchers to workplaces. By asking questions that "open boxes", we "outsiders and boundary-crossers" sought to expose contradictions between College and…

  19. On the Dirichlet's Box Principle

    ERIC Educational Resources Information Center

    Poon, Kin-Keung; Shiu, Wai-Chee

    2008-01-01

    In this note, we will focus on several applications on the Dirichlet's box principle in Discrete Mathematics lesson and number theory lesson. In addition, the main result is an innovative game on a triangular board developed by the authors. The game has been used in teaching and learning mathematics in Discrete Mathematics and some high schools in…

  20. The Bird Box Survey Project

    ERIC Educational Resources Information Center

    Willis, Patrick

    2014-01-01

    When high school students are asked what's the best part of science class, many will say it's the field trips. Students enjoy engaging in authentic, community-based science outside the classroom. To capitalize on this, Patrick Willis created the Bird Box Survey Project for his introductory field biology class. The project takes students…

  1. Effects of Gold Salt Speciation and Structure of Human and Bovine Serum Albumins on the Synthesis and Stability of Gold Nanostructures

    PubMed Central

    Miranda, Érica G. A.; Tofanello, Aryane; Brito, Adrianne M. M.; Lopes, David M.; Albuquerque, Lindomar J. C.; de Castro, Carlos E.; Costa, Fanny N.; Giacomelli, Fernando C.; Ferreira, Fabio F.; Araújo-Chaves, Juliana C.; Nantes, Iseli L.

    2016-01-01

    the gold surface. Therefore, the cysteine side chain of albumins is important for the colloidal stabilization of GNPs rather than as the reducing agent for the synthesis. Despite the presence of more reactive gold species at more acidic pH values, i.e., below 6.0, in these conditions the loss of native albumin structure impaired GNP synthesis. Alkaline pH values (9–12) combined the unfavorable conditions of denaturated protein structure with less reactive gold species. Therefore, an optimal condition for the synthesis of GNPs using serum albumins involves more reactive gold salt species combined with a reducing and negatively charged form of the protein, all favored at pH 6–7. PMID:27066476

  2. Effects of Gold Salt Speciation and Structure of Human and Bovine Serum Albumins on the Synthesis and Stability of Gold Nanostructures.

    PubMed

    Miranda, Érica G A; Tofanello, Aryane; Brito, Adrianne M M; Lopes, David M; Albuquerque, Lindomar J C; de Castro, Carlos E; Costa, Fanny N; Giacomelli, Fernando C; Ferreira, Fabio F; Araújo-Chaves, Juliana C; Nantes, Iseli L

    2016-01-01

    gold surface. Therefore, the cysteine side chain of albumins is important for the colloidal stabilization of GNPs rather than as the reducing agent for the synthesis. Despite the presence of more reactive gold species at more acidic pH values, i.e., below 6.0, in these conditions the loss of native albumin structure impaired GNP synthesis. Alkaline pH values (9-12) combined the unfavorable conditions of denaturated protein structure with less reactive gold species. Therefore, an optimal condition for the synthesis of GNPs using serum albumins involves more reactive gold salt species combined with a reducing and negatively charged form of the protein, all favored at pH 6-7.

  3. Effects of Gold Salt Speciation and Structure of Human and Bovine Serum Albumins on the Synthesis and Stability of Gold Nanostructures.

    PubMed

    Miranda, Érica G A; Tofanello, Aryane; Brito, Adrianne M M; Lopes, David M; Albuquerque, Lindomar J C; de Castro, Carlos E; Costa, Fanny N; Giacomelli, Fernando C; Ferreira, Fabio F; Araújo-Chaves, Juliana C; Nantes, Iseli L

    2016-01-01

    gold surface. Therefore, the cysteine side chain of albumins is important for the colloidal stabilization of GNPs rather than as the reducing agent for the synthesis. Despite the presence of more reactive gold species at more acidic pH values, i.e., below 6.0, in these conditions the loss of native albumin structure impaired GNP synthesis. Alkaline pH values (9-12) combined the unfavorable conditions of denaturated protein structure with less reactive gold species. Therefore, an optimal condition for the synthesis of GNPs using serum albumins involves more reactive gold salt species combined with a reducing and negatively charged form of the protein, all favored at pH 6-7. PMID:27066476

  4. Evaluation of bike boxes at signalized intersections.

    PubMed

    Dill, Jennifer; Monsere, Christopher M; McNeil, Nathan

    2012-01-01

    This paper presents a before-after study of bike boxes at 10 signalized intersections in Portland, Oregon. The bike boxes, also known as advanced stop lines or advanced stop boxes, were installed to increase visibility of cyclists and reduce conflicts between motor vehicles and cyclists, particularly in potential "right-hook" situations. Before and after video were analyzed for seven intersections with green bike boxes, three intersections with uncolored bike boxes, and two control intersections. User perceptions were measured through surveys of cyclists passing through five of the bike box intersections and of motorists working downtown, where the boxes were concentrated. Both the observations and survey of motorists found a high rate of compliance and understanding of the markings. Overall, 73% of the stopping motor vehicles did not encroach at all into the bike box. Both motor vehicle and bicycle encroachment in the pedestrian crosswalk fell significantly at the bike box locations compared to the control intersections. The bike boxes had mixed effects on the motorists' encroachment in the bicycle lane. The number of observed conflicts at the bike box locations decreased, while the total number of cyclists and motor vehicles turning right increased. Negative-binomial models based upon the data predict fewer conflicts with the boxes, particularly as right-turning motor vehicle volumes increase. Observations of yielding behavior at two bike box and one control intersection found an improvement in motorists yielding to cyclists at the bike box locations. Differences in the traffic volumes and location contexts make firm conclusions about the effects of green coloring of the boxes difficult. Higher shares of surveyed motorists felt that the bike boxes made driving safer rather than more dangerous, even when the sample was narrowed to respondents who were not also cyclists. Over three-quarters of the surveyed cyclists thought that the boxes made the intersection safer.

  5. [The design of heat dissipation of the field low temperature box for storage and transportation].

    PubMed

    Wei, Jiancang; Suin, Jianjun; Wu, Jian

    2013-02-01

    Because of the compact structure of the field low temperature box for storage and transportation, which is due to the same small space where the compressor, the condenser, the control circuit, the battery and the power supply device are all placed in, the design for heat dissipation and ventilation is of critical importance for the stability and reliability of the box. Several design schemes of the heat dissipation design of the box were simulated using the FLOEFD hot fluid analysis software in this study. Different distributions of the temperature field in every design scheme were constructed intimately in the present study. It is well concluded that according to the result of the simulation analysis, the optimal heat dissipation design is decent for the field low temperature box for storage and transportation, and the box can operate smoothly for a long time using the results of the design. PMID:23488142

  6. Effect of base-pair stability of nearest-neighbor nucleotides on the fidelity of deoxyribonucleic acid synthesis.

    PubMed

    Patten, J E; So, A G; Downey, K M

    1984-04-10

    The influence of the stability of base pairs formed by nearest-neighbor nucleotides on misincorporation frequency has been studied with the large fragment of DNA polymerase I, the alternating DNA copolymers, poly(dI-dC) and poly-(dG-dC), as template-primers, and dGTP, dITP, and dCTP as substrates. We have utilized the difference in thermodynamic stability between the doubly H-bonded I X C base pair and triply H-bonded G X C base pair to examine the effects of base-pair stability of both the "preceding" and the "following" nucleotides on the frequency of insertion of a mismatched nucleotide, as well as on its stable incorporation into polynucleotide. The present studies demonstrate that the stability of the base pairs formed by nearest-neighbor nucleotides affects the frequency of incorporation of noncomplementary nucleotides. Misincorporation frequency is increased when the nearest-neighbor nucleotides form more stable base pairs with the corresponding nucleotides in the template and is decreased when they form less stable base pairs. The stability of the base pair formed by a nucleotide either preceding (5' to) or following (3' to) a misincorporated nucleotide influences misincorporation frequency, but by different mechanisms. The stability of base pairs formed by preceding nucleotides affects the rate of insertion of mismatched nucleotide but does not protect the mismatched nucleotide from removal by the 3' to 5' exonuclease activity. In contrast, the stability of a base pair formed by a following nucleotide determines whether a misincorporated nucleotide is extended or excised by affecting the ability of the enzyme to edit errors of incorporation. PMID:6722115

  7. Cytotoxic heteroleptic heptacoordinate salan zirconium(iv)-bis-chelates - synthesis, aqueous stability and X-ray structure analysis.

    PubMed

    Schneider, Fabian; Zhao, Tiankun; Huhn, Thomas

    2016-08-01

    Herein we report the synthesis and structural characterization of a series of novel Zr(iv)salan complexes. The initial metalation product [(L1)2Zr] is highly water sensitive while ligand exchanged [L1Zr(dipic)] hydrolyses slowly with a bis-hydroxo Zr(iv) species identified by MS as an intermediate. [L1Zr(dipic)] is cytotoxic in the range of cisplatin against two human carcinoma cell lines. PMID:27459052

  8. Synthesis and characterization of chitosan/TiO2 composite beads for improving stability of porcine pancreatic lipase.

    PubMed

    Deveci, Ilyas; Doğaç, Yasemin Ispirli; Teke, Mustafa; Mercimek, Bedrettin

    2015-01-01

    The purpose of the present work is improving stability properties of porcine pancreatic lipase (triacylglycerol lipase, E.C.3.1.1.3) by immobilization on chitosan/TiO2 composite beads. The immobilization parameters were initial enzyme concentration (0.5-2 mg/ml), adsorption time (5-25 min), and glutaraldehyde concentration (1-4 % v/v). The optimum temperature (20-60 °C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70 °C), pH stability (4.0-9.0), and reusability (9 times) were investigated for characterization of immobilized lipase system. The optimum temperatures of free and immobilized lipase were 30 °C. The temperature profile of the immobilized lipase was spread over a large area. The optimum pH values for the free lipase and immobilized lipase were found to be 6.5 and 7.5, respectively. The thermal stability of immobilized lipase was evaluated, and it maintained 45 % activity at 70 °C. But, at this temperature, soluble lipase protected only 15 % activity. Also, the structural characterization of chitosan/TiO2 composite beads was analyzed with scanning electron microscope (SEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and attenuated total reflection Fourier transform infrared spectroscopy analysis (ATR-FTIR). The significance of this study is improving of stability properties of lipase for the industrial usage especially production of biodiesel and dairy products. PMID:25359676

  9. Glove box for water pit applications

    DOEpatents

    Mills, William C.; Rabe, Richard A.

    2005-01-18

    A glove box assembly that includes a glove box enclosure attached to a longitudinally extending hollow tube having an entranceway, wherein the portion of the tube is in a liquid environment. An elevator member is provided for raising an object that is introduced into the hollow tube from the liquid environment to a gas environment inside the glove box enclosure while maintaining total containment.

  10. The Guide to the Ecology Box.

    ERIC Educational Resources Information Center

    Ontario Inst. for Studies in Education, Toronto.

    Cooperating with the Canadian Commission for UNESCO, the Ontario Institute for Studies in Education has prepared boxes of experimental curriculum materials on the subject of ecology. This guide summarizes the design and contents of the boxes and provides instructions for those using the boxes--principals, teachers, parents, librarians, and…

  11. The Heuristic Interpretation of Box Plots

    ERIC Educational Resources Information Center

    Lem, Stephanie; Onghena, Patrick; Verschaffel, Lieven; Van Dooren, Wim

    2013-01-01

    Box plots are frequently used, but are often misinterpreted by students. Especially the area of the box in box plots is often misinterpreted as representing number or proportion of observations, while it actually represents their density. In a first study, reaction time evidence was used to test whether heuristic reasoning underlies this…

  12. Facile one-pot synthesis of L-proline-stabilized fluorescent gold nanoclusters and its application as sensing probes for serum iron.

    PubMed

    Mu, Xiaoyu; Qi, Li; Dong, Ping; Qiao, Juan; Hou, Jian; Nie, Zongxiu; Ma, Huimin

    2013-11-15

    Gold nanoclusters (Au NCs) possess outstanding physical and chemical attributes that make them excellent scaffolds for the construction of novel chemical and biological sensors. In this study, a simple one-pot synthesis method, employing l-proline as the stabilizer, was presented for preparation of fluorescent Au NCs. This strategy allowed the generation of water-soluble Au NCs within a short time of 15 min. The as-prepared Au NCs exhibited a bluish fluorescence emission at 440 nm and a quantum yield of 2.94%. Based on the aggregation-induced fluorescence quenching mechanism, the Au NCs provided favorable biocompatibility, high sensitivity and good selectivity for the measurement of ferric ion (Fe(3+)). Furthermore, serum samples were analyzed for the serum iron contents by using this proposed biocompatible fluorescent sensor, indicating the potential value of this Au NCs-based fluorescent sensor for application in biological and clinical analysis.

  13. Design of an effective bifunctional catalyst organotriphosphonic acid-functionalized ferric alginate (ATMP-FA) and optimization by Box-Behnken model for biodiesel esterification synthesis of oleic acid over ATMP-FA.

    PubMed

    Liu, Wei; Yin, Ping; Liu, Xiguang; Qu, Rongjun

    2014-12-01

    Biodiesel production has become an intense research area because of rapidly depleting energy reserves and increasing petroleum prices together with environmental concerns. This paper focused on the optimization of the catalytic performance in the esterification reaction of oleic acid for biodiesel production over the bifunctional catalyst organotriphosphonic acid-functionalized ferric alginate ATMP-FA. The reaction parameters including catalyst amount, ethanol to oleic acid molar ratio and reaction temperature have been optimized by response surface methodology (RSM) using the Box-Behnken model. It was found that the reaction temperature was the most significant factor, and the best conversion ratio of oleic acid could reach 93.17% under the reaction conditions with 9.53% of catalyst amount and 8.62:1 of ethanol to oleic acid molar ratio at 91.0 °C. The research results show that two catalytic species could work cooperatively to promote the esterification reaction, and the bifunctional ATMP-FA is a potential catalyst for biodiesel production.

  14. The DNA damage checkpoint pathway promotes extensive resection and nucleotide synthesis to facilitate homologous recombination repair and genome stability in fission yeast.

    PubMed

    Blaikley, Elizabeth J; Tinline-Purvis, Helen; Kasparek, Torben R; Marguerat, Samuel; Sarkar, Sovan; Hulme, Lydia; Hussey, Sharon; Wee, Boon-Yu; Deegan, Rachel S; Walker, Carol A; Pai, Chen-Chun; Bähler, Jürg; Nakagawa, Takuro; Humphrey, Timothy C

    2014-05-01

    DNA double-strand breaks (DSBs) can cause chromosomal rearrangements and extensive loss of heterozygosity (LOH), hallmarks of cancer cells. Yet, how such events are normally suppressed is unclear. Here we identify roles for the DNA damage checkpoint pathway in facilitating homologous recombination (HR) repair and suppressing extensive LOH and chromosomal rearrangements in response to a DSB. Accordingly, deletion of Rad3(ATR), Rad26ATRIP, Crb2(53BP1) or Cdc25 overexpression leads to reduced HR and increased break-induced chromosome loss and rearrangements. We find the DNA damage checkpoint pathway facilitates HR, in part, by promoting break-induced Cdt2-dependent nucleotide synthesis. We also identify additional roles for Rad17, the 9-1-1 complex and Chk1 activation in facilitating break-induced extensive resection and chromosome loss, thereby suppressing extensive LOH. Loss of Rad17 or the 9-1-1 complex results in a striking increase in break-induced isochromosome formation and very low levels of chromosome loss, suggesting the 9-1-1 complex acts as a nuclease processivity factor to facilitate extensive resection. Further, our data suggest redundant roles for Rad3ATR and Exo1 in facilitating extensive resection. We propose that the DNA damage checkpoint pathway coordinates resection and nucleotide synthesis, thereby promoting efficient HR repair and genome stability.

  15. The DNA damage checkpoint pathway promotes extensive resection and nucleotide synthesis to facilitate homologous recombination repair and genome stability in fission yeast

    PubMed Central

    Blaikley, Elizabeth J.; Tinline-Purvis, Helen; Kasparek, Torben R.; Marguerat, Samuel; Sarkar, Sovan; Hulme, Lydia; Hussey, Sharon; Wee, Boon-Yu; Deegan, Rachel S.; Walker, Carol A.; Pai, Chen-Chun; Bähler, Jürg; Nakagawa, Takuro; Humphrey, Timothy C.

    2014-01-01

    DNA double-strand breaks (DSBs) can cause chromosomal rearrangements and extensive loss of heterozygosity (LOH), hallmarks of cancer cells. Yet, how such events are normally suppressed is unclear. Here we identify roles for the DNA damage checkpoint pathway in facilitating homologous recombination (HR) repair and suppressing extensive LOH and chromosomal rearrangements in response to a DSB. Accordingly, deletion of Rad3ATR, Rad26ATRIP, Crb253BP1 or Cdc25 overexpression leads to reduced HR and increased break-induced chromosome loss and rearrangements. We find the DNA damage checkpoint pathway facilitates HR, in part, by promoting break-induced Cdt2-dependent nucleotide synthesis. We also identify additional roles for Rad17, the 9-1-1 complex and Chk1 activation in facilitating break-induced extensive resection and chromosome loss, thereby suppressing extensive LOH. Loss of Rad17 or the 9-1-1 complex results in a striking increase in break-induced isochromosome formation and very low levels of chromosome loss, suggesting the 9-1-1 complex acts as a nuclease processivity factor to facilitate extensive resection. Further, our data suggest redundant roles for Rad3ATR and Exo1 in facilitating extensive resection. We propose that the DNA damage checkpoint pathway coordinates resection and nucleotide synthesis, thereby promoting efficient HR repair and genome stability. PMID:24623809

  16. The DNA damage checkpoint pathway promotes extensive resection and nucleotide synthesis to facilitate homologous recombination repair and genome stability in fission yeast.

    PubMed

    Blaikley, Elizabeth J; Tinline-Purvis, Helen; Kasparek, Torben R; Marguerat, Samuel; Sarkar, Sovan; Hulme, Lydia; Hussey, Sharon; Wee, Boon-Yu; Deegan, Rachel S; Walker, Carol A; Pai, Chen-Chun; Bähler, Jürg; Nakagawa, Takuro; Humphrey, Timothy C

    2014-05-01

    DNA double-strand breaks (DSBs) can cause chromosomal rearrangements and extensive loss of heterozygosity (LOH), hallmarks of cancer cells. Yet, how such events are normally suppressed is unclear. Here we identify roles for the DNA damage checkpoint pathway in facilitating homologous recombination (HR) repair and suppressing extensive LOH and chromosomal rearrangements in response to a DSB. Accordingly, deletion of Rad3(ATR), Rad26ATRIP, Crb2(53BP1) or Cdc25 overexpression leads to reduced HR and increased break-induced chromosome loss and rearrangements. We find the DNA damage checkpoint pathway facilitates HR, in part, by promoting break-induced Cdt2-dependent nucleotide synthesis. We also identify additional roles for Rad17, the 9-1-1 complex and Chk1 activation in facilitating break-induced extensive resection and chromosome loss, thereby suppressing extensive LOH. Loss of Rad17 or the 9-1-1 complex results in a striking increase in break-induced isochromosome formation and very low levels of chromosome loss, suggesting the 9-1-1 complex acts as a nuclease processivity factor to facilitate extensive resection. Further, our data suggest redundant roles for Rad3ATR and Exo1 in facilitating extensive resection. We propose that the DNA damage checkpoint pathway coordinates resection and nucleotide synthesis, thereby promoting efficient HR repair and genome stability. PMID:24623809

  17. Synthesis and controllable oxidation of monodisperse cobalt-doped wüstite nanoparticles and their core-shell stability and exchange-bias stabilization.

    PubMed

    Chen, Chih-Jung; Chiang, Ray-Kuang; Kamali, Saeed; Wang, Sue-Lein

    2015-09-14

    Cobalt-doped wüstite (CWT), Co0.33Fe0.67O, nanoparticles were prepared via the thermal decomposition of CoFe2-oleate complexes in organic solvents. A controllable oxidation process was then performed to obtain Co0.33Fe0.67O/CoFe2O4 core-shell structures with different core-to-shell volume ratios and exchange bias properties. The oxidized core-shell samples with a ∼4 nm CoFe2O4 shell showed good resistance to oxygen transmission. Thus, it is inferred that the cobalt ferrite shell provides a better oxidation barrier performance than magnetite in the un-doped case. The hysteresis loops of the oxidized 19 nm samples exhibited a high exchange bias field (H(E)), an enhanced coercivity field (H(C)), and a pronounced vertical shift, thus indicating the presence of a strong exchange bias coupling effect. More importantly, the onset temperature of H(E) was found to be higher than 200 K, which suggests that cobalt doping increases the Néel temperature (T(N)) of the CWT core. In general, the results show that the homogeneous dispersion of Co in iron precursors improves the stability of the final CWT nanoparticles. Moreover, the CoFe2O4 shells formed following oxidation increase the oxidation resistance of the CWT cores and enhance their anisotropy energy.

  18. Synthesis and controllable oxidation of monodisperse cobalt-doped wüstite nanoparticles and their core-shell stability and exchange-bias stabilization.

    PubMed

    Chen, Chih-Jung; Chiang, Ray-Kuang; Kamali, Saeed; Wang, Sue-Lein

    2015-09-14

    Cobalt-doped wüstite (CWT), Co0.33Fe0.67O, nanoparticles were prepared via the thermal decomposition of CoFe2-oleate complexes in organic solvents. A controllable oxidation process was then performed to obtain Co0.33Fe0.67O/CoFe2O4 core-shell structures with different core-to-shell volume ratios and exchange bias properties. The oxidized core-shell samples with a ∼4 nm CoFe2O4 shell showed good resistance to oxygen transmission. Thus, it is inferred that the cobalt ferrite shell provides a better oxidation barrier performance than magnetite in the un-doped case. The hysteresis loops of the oxidized 19 nm samples exhibited a high exchange bias field (H(E)), an enhanced coercivity field (H(C)), and a pronounced vertical shift, thus indicating the presence of a strong exchange bias coupling effect. More importantly, the onset temperature of H(E) was found to be higher than 200 K, which suggests that cobalt doping increases the Néel temperature (T(N)) of the CWT core. In general, the results show that the homogeneous dispersion of Co in iron precursors improves the stability of the final CWT nanoparticles. Moreover, the CoFe2O4 shells formed following oxidation increase the oxidation resistance of the CWT cores and enhance their anisotropy energy. PMID:26243163

  19. Illumination box and camera system

    DOEpatents

    Haas, Jeffrey S.; Kelly, Fredrick R.; Bushman, John F.; Wiefel, Michael H.; Jensen, Wayne A.; Klunder, Gregory L.

    2002-01-01

    A hand portable, field-deployable thin-layer chromatography (TLC) unit and a hand portable, battery-operated unit for development, illumination, and data acquisition of the TLC plates contain many miniaturized features that permit a large number of samples to be processed efficiently. The TLC unit includes a solvent tank, a holder for TLC plates, and a variety of tool chambers for storing TLC plates, solvent, and pipettes. After processing in the TLC unit, a TLC plate is positioned in a collapsible illumination box, where the box and a CCD camera are optically aligned for optimal pixel resolution of the CCD images of the TLC plate. The TLC system includes an improved development chamber for chemical development of TLC plates that prevents solvent overflow.

  20. Synthesis and controllable oxidation of monodisperse cobalt-doped wüstite nanoparticles and their core-shell stability and exchange-bias stabilization

    NASA Astrophysics Data System (ADS)

    Chen, Chih-Jung; Chiang, Ray-Kuang; Kamali, Saeed; Wang, Sue-Lein

    2015-08-01

    Cobalt-doped wüstite (CWT), Co0.33Fe0.67O, nanoparticles were prepared via the thermal decomposition of CoFe2-oleate complexes in organic solvents. A controllable oxidation process was then performed to obtain Co0.33Fe0.67O/CoFe2O4 core-shell structures with different core-to-shell volume ratios and exchange bias properties. The oxidized core-shell samples with a ~4 nm CoFe2O4 shell showed good resistance to oxygen transmission. Thus, it is inferred that the cobalt ferrite shell provides a better oxidation barrier performance than magnetite in the un-doped case. The hysteresis loops of the oxidized 19 nm samples exhibited a high exchange bias field (HE), an enhanced coercivity field (HC), and a pronounced vertical shift, thus indicating the presence of a strong exchange bias coupling effect. More importantly, the onset temperature of HE was found to be higher than 200 K, which suggests that cobalt doping increases the Néel temperature (TN) of the CWT core. In general, the results show that the homogeneous dispersion of Co in iron precursors improves the stability of the final CWT nanoparticles. Moreover, the CoFe2O4 shells formed following oxidation increase the oxidation resistance of the CWT cores and enhance their anisotropy energy.Cobalt-doped wüstite (CWT), Co0.33Fe0.67O, nanoparticles were prepared via the thermal decomposition of CoFe2-oleate complexes in organic solvents. A controllable oxidation process was then performed to obtain Co0.33Fe0.67O/CoFe2O4 core-shell structures with different core-to-shell volume ratios and exchange bias properties. The oxidized core-shell samples with a ~4 nm CoFe2O4 shell showed good resistance to oxygen transmission. Thus, it is inferred that the cobalt ferrite shell provides a better oxidation barrier performance than magnetite in the un-doped case. The hysteresis loops of the oxidized 19 nm samples exhibited a high exchange bias field (HE), an enhanced coercivity field (HC), and a pronounced vertical shift, thus

  1. Synthesis, characterization, solubility and stability studies of hydrate cocrystal of antitubercular Isoniazid with antioxidant and anti-bacterial Protocatechuic acid

    NASA Astrophysics Data System (ADS)

    Mashhadi, Syed Muddassir Ali; Yunus, Uzma; Bhatti, Moazzam Hussain; Ahmed, Imtiaz; Tahir, Muhammad Nawaz

    2016-08-01

    Isoniazid is an important component used in "triple therapy" to combat tuberculosis. It has reduced Tabletting formulations stability. Anti-oxidants are obligatory to counter oxidative stress, pulmonary inflammation, and free radical burst from macrophages caused in tuberculosis and other diseases. In the present study a hydrate cocrystal of Isoniazid with anti-oxidant and anti-inflammatory and anti-bacterial Protocatechuic acid (3,4-dihydroxybenzoic acid) in 1:1 is reported. This Cocrystal may have improved tabletting stability and anti-oxidant properties. Cocrystal structure analysis confirmed the existence of pyridine-carboxylic acid synthon in the Cocrystal. Other synthons of different graph sets involving Nsbnd H···O and Osbnd H···N bonds are formed between hydrazide group of isoniazid and coformer. Solubility studies revealed that cocrystal is less soluble as compared to isoniazid in buffer at pH 7.4 at 22 °C while stability studies at 80 °C for 24 h period disclosed the fact that cocrystal has higher stability than that of isoniazid.

  2. Size-controlled synthesis of near-monodisperse gold nanoparticles in the 1-4 nm range using polymeric stabilizers.

    PubMed

    Hussain, Irshad; Graham, Susan; Wang, Zhenxin; Tan, Bien; Sherrington, David C; Rannard, Steven P; Cooper, Andrew I; Brust, Mathias

    2005-11-30

    We report here a simple one-step protocol for the preparation of near-monodisperse gold hydrosols in the small size regime (<5 nm). The particle size can be controlled by varying the concentration of the stabilizing polymer, which can be readily displaced by thiol ligands to yield monolayer protected clusters of the usual type.

  3. Carbohydrate-based Cu(I) stabilizing ligands and their use in the synthesis of carbohydrate-ferrocene conjugates.

    PubMed

    Schmidt, Magnus S; Leitner, Kim; Welter, Moritz; Wurmthaler, Lena A; Ringwald, Markus

    2014-03-31

    A series of carbohydrate-ferrocene conjugates have been synthesized by copper(I)-catalyzed cycloaddition of carbohydrate-azides and ethynylferrocene (CuAAC). Newly carbohydrate-based tris-triazoles have been used as Cu(I) stabilizing ligands and showed at least comparable, in some cases even better results compared to the use of tris-(benzyltriazolylmethyl)amine (TBTA).

  4. Versatile synthesis of PHMB-stabilized silver nanoparticles and their significant stimulating effect on fodder beet (Beta vulgaris L.).

    PubMed

    Gusev, Alexander А; Kudrinsky, Alexey A; Zakharova, Olga V; Klimov, Alexey I; Zherebin, Pavel M; Lisichkin, George V; Vasyukova, Inna A; Denisov, Albert N; Krutyakov, Yurii A

    2016-05-01

    Silver nanoparticles (AgNPs) are well-known bactericidal agents. However, information about the influence of AgNPs on the morphometric parameters and biochemical status of most important agricultural crops is limited. The present study reports the influence of AgNPs stabilized with cationic polymer polyhexamethylene biguanide hydrochloride (PHMB) on growth, development, and biochemical status of fodder beet Beta vulgaris L. under laboratory and greenhouse conditions. PHMB-stabilized AgNPs were obtained via sodium borohydride reduction of silver nitrate in an aqueous solution. The average diameter of thus prepared AgNPs was 10 nm. It appears that the results of experiments with laboratory-grown beets in the nanosilver-containing medium, where germination of seeds and growth of roots were suppressed, do not correlate with the results of greenhouse experiments. The observed growth-stimulating action of PHMB-stabilized AgNPs can be explained by the change of activity of oxidases and, consequently, by the change of auxins amount in plant tissues. In beets grown in the presence of PHMB-stabilized AgNPs no negative deviations of biological parameters from normal values were registered. Furthermore, the SEM/EDS examination revealed no presence of silver in the tissues of the studied plants.

  5. Polymeric prodrug of bufalin for increasing solubility and stability: Synthesis and anticancer study in vitro and in vivo.

    PubMed

    Liu, Tao; Yuan, Xia; Jia, Tingting; Liu, Cheng; Ni, Zhenhua; Qin, Zongling; Yuan, Yi

    2016-06-15

    Bufalin (BUF) exhibits promising potential for the treatment of various human cancers. However, its poor water solubility and unsatisfying stability in water limit its further clinical applications. In the current study, we fabricated a novel poly(ethylene glycol) (PEG)-based polymeric prodrug of BUF, PEGS-BUF, to improve its water solubility and stability at the prerequisite of maintaining its original anticancer activity. Water soluble and biocompatible PEG was firstly reacted with maleic anhydride (MAH) to afford carboxyl-terminated PEG, PEG-MAH. Then the double bond was reacted with n-propyl mercaptan via the Michael addition reaction to afford PEGS-COOH. At last, the 3α-hydroxyl group of BUF was reacted with the terminal carboxyl group of PEGS-COOH via esterification reaction to afford the final polymeric prodrug, PEGS-BUF, endowing BUF good water solubility, stability, and anticancer activity. It was demonstrated that the water solubility and stability of PEGS-BUF improved dramatically compared with that of its small molecular counterpart, BUF. Besides, both in vitro and in vivo experiments showed that PEGS-BUF exhibited comparable anticancer activity in comparison with that of free BUF. PMID:27132167

  6. Versatile synthesis of PHMB-stabilized silver nanoparticles and their significant stimulating effect on fodder beet (Beta vulgaris L.).

    PubMed

    Gusev, Alexander А; Kudrinsky, Alexey A; Zakharova, Olga V; Klimov, Alexey I; Zherebin, Pavel M; Lisichkin, George V; Vasyukova, Inna A; Denisov, Albert N; Krutyakov, Yurii A

    2016-05-01

    Silver nanoparticles (AgNPs) are well-known bactericidal agents. However, information about the influence of AgNPs on the morphometric parameters and biochemical status of most important agricultural crops is limited. The present study reports the influence of AgNPs stabilized with cationic polymer polyhexamethylene biguanide hydrochloride (PHMB) on growth, development, and biochemical status of fodder beet Beta vulgaris L. under laboratory and greenhouse conditions. PHMB-stabilized AgNPs were obtained via sodium borohydride reduction of silver nitrate in an aqueous solution. The average diameter of thus prepared AgNPs was 10 nm. It appears that the results of experiments with laboratory-grown beets in the nanosilver-containing medium, where germination of seeds and growth of roots were suppressed, do not correlate with the results of greenhouse experiments. The observed growth-stimulating action of PHMB-stabilized AgNPs can be explained by the change of activity of oxidases and, consequently, by the change of auxins amount in plant tissues. In beets grown in the presence of PHMB-stabilized AgNPs no negative deviations of biological parameters from normal values were registered. Furthermore, the SEM/EDS examination revealed no presence of silver in the tissues of the studied plants. PMID:26952409

  7. A comparative study of the effect of α-, β-, and γ-cyclodextrins as stabilizing agents in the synthesis of silver nanoparticles using a green chemistry method.

    PubMed

    Suárez-Cerda, Javier; Nuñez, Gabriel Alonso; Espinoza-Gómez, Heriberto; Flores-López, Lucía Z

    2014-10-01

    This paper describes the effect of different types of cyclodextrins (CDs) in the synthesis of silver nanoparticles (Ag-NPs), using an easy green chemistry method. The Ag-NPs were obtained using an aqueous silver nitrate solution (AgNO3) with α-, β-, or γ-CDs (aqueous solutions) as stabilizing agents, employing the chemical reduction method with citric acid as a reducing agent. A comparative study was done to determine which cyclodextrin (CD) was the best stabilizing agent, and we found out that β-CD was the best due to the number of glucopyranose units in its structure. The formation of the Ag-NPs was demonstrated by analysis of UV-vis spectroscopy, atomic force microscopy (AFM), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). SEM-EDS showed the formation of a cluster with a significant amount of silver, for β-CD-Ag-NPs, spherical agglomerates can be observed. However, for α-, γ-CD, the agglomerates do not have a specific form, but their appearance is porous. TEM analysis shows spherical nanoparticles in shape and size between ~0.5 to 7 nm. The clear lattice fringes in TEM images and the typical selected area electron diffraction (SAED) pattern, showed that the Ag-NPs obtained were highly crystalline with a face cubic center structure (FCC). PMID:25175183

  8. Synthesis of citrate-stabilized hydrocolloids of hydroxyapatite through a novel two-stage method: a possible aggregates-breakdown mechanism of colloid formation.

    PubMed

    Li, Cuicui; Zhao, Liping; Han, Jingjia; Wang, Ruifang; Xiong, Chengdong; Xie, Xingyi

    2011-08-15

    Long-term stable (>2 years) hydrocolloids of hydroxyapatite (HA) were synthesized via a low-temperature (18-50 °C) reaction of aqueous ammonium phosphate with calcium nitrate in the presence of citrate ions, followed by an aging process at high temperature (80-99 °C) for 4 h. Changing the reaction and/or aging temperature seldom yielded stable HA hydrocolloids. The as-prepared hydrocolloids were desalinated through ultrafiltration where their average particle size gradually decreased, bottomed out at 100-400 μS/cm, and sharply increased in parallel with a decrease in solution conductivity. The colloid formation is most likely through a temperature-sensitive aggregates-breakdown process. During low-temperature reaction, citrate-calcium chelation bridges the growing HA particles into loose aggregates. High-temperature aging disrupts these inter-particle links and thus breaks the aggregates, imparting negative charges to the HA, forming colloidal particles stabilized by surface charge. The decrease in mean particle size during early ultrafiltration suggested that the aggregate breakdown further proceeded through desalination. In conclusion, the temperature-dependent interactions between citrate ions and calcium sites on HA particles played key roles in the synthesis and stability of the HA colloids.

  9. A comparative study of the effect of α-, β-, and γ-cyclodextrins as stabilizing agents in the synthesis of silver nanoparticles using a green chemistry method.

    PubMed

    Suárez-Cerda, Javier; Nuñez, Gabriel Alonso; Espinoza-Gómez, Heriberto; Flores-López, Lucía Z

    2014-10-01

    This paper describes the effect of different types of cyclodextrins (CDs) in the synthesis of silver nanoparticles (Ag-NPs), using an easy green chemistry method. The Ag-NPs were obtained using an aqueous silver nitrate solution (AgNO3) with α-, β-, or γ-CDs (aqueous solutions) as stabilizing agents, employing the chemical reduction method with citric acid as a reducing agent. A comparative study was done to determine which cyclodextrin (CD) was the best stabilizing agent, and we found out that β-CD was the best due to the number of glucopyranose units in its structure. The formation of the Ag-NPs was demonstrated by analysis of UV-vis spectroscopy, atomic force microscopy (AFM), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). SEM-EDS showed the formation of a cluster with a significant amount of silver, for β-CD-Ag-NPs, spherical agglomerates can be observed. However, for α-, γ-CD, the agglomerates do not have a specific form, but their appearance is porous. TEM analysis shows spherical nanoparticles in shape and size between ~0.5 to 7 nm. The clear lattice fringes in TEM images and the typical selected area electron diffraction (SAED) pattern, showed that the Ag-NPs obtained were highly crystalline with a face cubic center structure (FCC).

  10. The transition from noncoded to coded protein synthesis: did coding mRNAs arise from stability-enhancing binding partners to tRNA?

    PubMed Central

    2010-01-01

    Background Understanding the origin of protein synthesis has been notoriously difficult. We have taken as a starting premise Wolf and Koonin's view that "evolution of the translation system is envisaged to occur in a compartmentalized ensemble of replicating, co-selected RNA segments, i.e., in an RNA world containing ribozymes with versatile activities". Presentation of the hypothesis We propose that coded protein synthesis arose from a noncoded process in an RNA world as a natural consequence of the accumulation of a range of early tRNAs and their serendipitous RNA binding partners. We propose that, initially, RNA molecules with 3' CCA termini that could be aminoacylated by ribozymes, together with an ancestral peptidyl transferase ribozyme, produced small peptides with random or repetitive sequences. Our concept is that the first tRNA arose in this context from the ligation of two RNA hairpins and could be similarly aminoacylated at its 3' end to become a substrate for peptidyl transfer catalyzed by the ancestral ribozyme. Within this RNA world we hypothesize that proto-mRNAs appeared first simply as serendipitous binding partners, forming complementary base pair interactions with the anticodon loops of tRNA pairs. Initially this may have enhanced stability of the paired tRNA molecules so they were held together in close proximity, better positioning the 3' CCA termini for peptidyl transfer and enhancing the rate of peptide synthesis. If there were a selective advantage for the ensemble through the peptide products synthesized, it would provide a natural pathway for the evolution of a coding system with the expansion of a cohort of different tRNAs and their binding partners. The whole process could have occurred quite unremarkably for such a profound acquisition. Testing the hypothesis It should be possible to test the different parts of our model using the isolated contemporary 50S ribosomal subunit initially, and then with RNAs transcribed in vitro together

  11. Structured superparamagnetic nanoparticles for high performance mediator of magnetic fluid hyperthermia: synthesis, colloidal stability and biocompatibility evaluation.

    PubMed

    Thorat, N D; Otari, S V; Bohara, R A; Yadav, H M; Khot, V M; Salunkhe, A B; Phadatare, M R; Prasad, A I; Ningthoujam, R S; Pawar, S H

    2014-09-01

    Core-shell structures with magnetic core and metal/polymer shell provide a new opportunity for constructing highly efficient mediator for magnetic fluid hyperthermia. Herein, a facile method is described for the synthesis of superparamagnetic LSMO@Pluronic F127 core-shell nanoparticles. Initially, the surface of the LSMO nanoparticles is functionalized with oleic acid and the polymeric shell formation is achieved through hydrophobic interactions with oleic acid. Each step is optimized to get good dispersion and less aggregation. This methodology results into core-shell formation, of average diameter less than 40 nm, which was stable under physiological conditions. After making a core-shell formulation, a significant increase of specific absorption rate (up to 300%) has been achieved with variation of the magnetization (<20%). Furthermore, this high heating capacity can be maintained in various simulated physiological conditions. The observed specific absorption rate is almost higher than Fe3O4. MTT assay is used to evaluate the toxicity of bare and core-shell MNPs. The mechanism of cell death by necrosis and apoptosis is studied with sequential staining of acridine orange and ethidium bromide using fluorescence and confocal microscopy. The present work reports a facile method for the synthesis of core-shell structure which significantly improves SAR and biocompatibility of bare LSMO MNPs, indicating potential application for hyperthermia. PMID:25063164

  12. Temperature-induced partially unfolded state of hUBF HMG Box-5: conformational and dynamic investigations of the Box-5 thermal intermediate ensemble.

    PubMed

    Liu, Zhijun; Zhang, Jiahai; Wang, Xingsheng; Ding, Yanwei; Wu, Jihui; Shi, Yunyu

    2009-11-01

    Human upstream binding factor (hUBF) HMG Box-5 is a highly conserved protein domain, containing 84 amino acids and belonging to the family of the nonspecific DNA-binding HMG boxes. Its native structure adopts a twisted L shape, which consists of three alpha-helices and two hydrophobic cores: the major wing and the minor wing. In this article, we report a reversible three-state thermal unfolding equilibrium of hUBF HMG Box-5, which is investigated by differential scanning calorimetry (DSC), circular dichroism spectroscopy, fluorescence spectroscopy, and NMR spectroscopy. DSC data show that Box-5 unfolds reversibly in two separate stages. Spectroscopic analyses suggest that different structural elements exhibit noncooperative transitions during the unfolding process and that the major form of the Box-5 thermal intermediate ensemble at 55 degrees C shows partially unfolded characteristics. Compared with previous thermal stability studies of other boxes, it appears that Box-5 possesses a more stable major wing and two well separated subdomains. NMR chemical shift index and sequential (1)H(N) (i)-(1)H(N) (i+1) NOE analyses indicate that helices 1 and 2 are native-like in the thermal intermediate ensemble, while helix 3 is partially unfolded. Detailed NMR relaxation dynamics are compared between the native state and the intermediate ensemble. Our results implicate a fluid helix-turn-helix folding model of Box-5, where helices 1 and 2 potentially form the helix 1-turn-helix 2 motif in the intermediate, while helix 3 is consolidated only as two hydrophobic cores form to stabilize the native structure.

  13. Synthesis, pH-Dependent, and Plasma Stability of Meropenem Prodrugs for Potential Use Against Drug-Resistant Tuberculosis

    PubMed Central

    Teitelbaum, Aaron M.; Meissner, Anja; Harding, Ryan A.; Wong, Christopher A.; Aldrich, Courtney C.; Remmel, Rory P.

    2013-01-01

    Meropenem, a broad-spectrum parenteral β-lactam antibiotic, in combination with clavulanate has recently shown efficacy in patients with extensively drug-resistant tuberculosis. As a result of meropenem’s short half-life and lack of oral bioavailability, the development of an oral therapy is warranted for TB treatment in underserved countries where chronic parenteral therapy is impractical. To improve the oral absorption of meropenem, several alkyloxycarbonyloxyalkyl ester prodrugs with increased lipophilicity were synthesized and their stability in physiological aqueous solutions and guinea pig as well as human plasma was evaluated. The stability of prodrugs in aqueous solution at pH 6.0 and 7.4 was significantly dependent on the ester promoiety with the major degradation product identified as the parent compound meropenem. However, in simulated gastrointestinal fluid (pH 1.2) the major degradation product identified was ring-opened meropenem with the promoiety still intact, suggesting the gastrointestinal environment may reduce the absorption of meropenem prodrugs in vivo unless administered as an enteric-coated formulation. Additionally, the stability of the most aqueous stable prodrugs in guinea pig or human plasma was short, implying a rapid release of parent meropenem. PMID:23845282

  14. New hot box solar cooker

    SciTech Connect

    Wang Xiping; Hou Shuqin; Sha Yongling; Liu Zude

    1992-12-31

    At present, over 100,000 solar cookers are in service in China. Most of these are concentrating cookers, making use of reflectors to concentrate sunlight at the cooking area. These cookers offer higher efficiency, more power and shorter cooking times. Since 1975 the authors have researched solar energy applications and, specifically, solar cookers. The major work has been the development of design calculations, selection of structure and materials, and performance testing. This paper describes the testing of several collection surface structures and box structures.

  15. Voronoi Diagrams Without Bounding Boxes

    NASA Astrophysics Data System (ADS)

    Sang, E. T. K.

    2015-10-01

    We present a technique for presenting geographic data in Voronoi diagrams without having to specify a bounding box. The method restricts Voronoi cells to points within a user-defined distance of the data points. The mathematical foundation of the approach is presented as well. The cell clipping method is particularly useful for presenting geographic data that is spread in an irregular way over a map, as for example the Dutch dialect data displayed in Figure 2. The automatic generation of reasonable cell boundaries also makes redundant a frequently used solution to this problem that requires data owners to specify region boundaries, as in Goebl (2010) and Nerbonne et al (2011).

  16. Thermohaline circulation and its box models simulation

    NASA Astrophysics Data System (ADS)

    Bazyura, Kateryna; Polonsky, Alexander; Sannikov, Viktor

    2014-05-01

    cases of using linear and nonlinear seawater state equation. In the frame of four-box model it is shown that: 1) The occurrence of the thermohaline catastrophe, which is likely happened at Younger Dryas period or developed as Heinrich events in the past, is improbable in modern climate epoch. 2) Choice of nonlinear seawater equitation of state leads to stabilization of warm mode of THC, which corresponds to modern climate state. 3) Typical white noise in heat and freshwater fluxes leads to generation of multidecadal oscillations of volume transport. Time-scale of these oscillations coincides with Atlantic Multidecadal oscillation periodicity. So, it is shown that that recent climate is characterized by quasi-periodical stable multidecadal THC warm regime. Stocker, T. F., 2000: Past and future reorganisations in the climate system. Quat. Sci.Rev, Vol. 19, P.301-319. Clark U., 2002: The role of the thermohaline circulation in abrupt climate change. Nature. Vol. 415, P.863-869. Rahmstorf S., 2002: Ocean circulation and climate during the past 120000 years. Nature. Vol. 419, P.207-214. Alley, R. B. & Clark, P. U., 1999: The deglaciation of the Northern Hemisphere: a global perspective. Annu.Rev. Earth Planet. Sci. Vol. 27, P.149-182. Griffies S.M., Tziperman E., 1995: A linear thermohaline oscillator driven by stochastic atmospheric forcing. Journal of Climate. Vol. 8. P. 2440-2453.

  17. Stability of Fe,Al-bearing bridgmanite in the lower mantle and synthesis of pure Fe-bridgmanite.

    PubMed

    Ismailova, Leyla; Bykova, Elena; Bykov, Maxim; Cerantola, Valerio; McCammon, Catherine; Boffa Ballaran, Tiziana; Bobrov, Andrei; Sinmyo, Ryosuke; Dubrovinskaia, Natalia; Glazyrin, Konstantin; Liermann, Hanns-Peter; Kupenko, Ilya; Hanfland, Michael; Prescher, Clemens; Prakapenka, Vitali; Svitlyk, Volodymyr; Dubrovinsky, Leonid

    2016-07-01

    The physical and chemical properties of Earth's mantle, as well as its dynamics and evolution, heavily depend on the phase composition of the region. On the basis of experiments in laser-heated diamond anvil cells, we demonstrate that Fe,Al-bearing bridgmanite (magnesium silicate perovskite) is stable to pressures over 120 GPa and temperatures above 3000 K. Ferric iron stabilizes Fe-rich bridgmanite such that we were able to synthesize pure iron bridgmanite at pressures between ~45 and 110 GPa. The compressibility of ferric iron-bearing bridgmanite is significantly different from any known bridgmanite, which has direct implications for the interpretation of seismic tomography data. PMID:27453945

  18. Stability of Fe,Al-bearing bridgmanite in the lower mantle and synthesis of pure Fe-bridgmanite

    PubMed Central

    Ismailova, Leyla; Bykova, Elena; Bykov, Maxim; Cerantola, Valerio; McCammon, Catherine; Boffa Ballaran, Tiziana; Bobrov, Andrei; Sinmyo, Ryosuke; Dubrovinskaia, Natalia; Glazyrin, Konstantin; Liermann, Hanns-Peter; Kupenko, Ilya; Hanfland, Michael; Prescher, Clemens; Prakapenka, Vitali; Svitlyk, Volodymyr; Dubrovinsky, Leonid

    2016-01-01

    The physical and chemical properties of Earth’s mantle, as well as its dynamics and evolution, heavily depend on the phase composition of the region. On the basis of experiments in laser-heated diamond anvil cells, we demonstrate that Fe,Al-bearing bridgmanite (magnesium silicate perovskite) is stable to pressures over 120 GPa and temperatures above 3000 K. Ferric iron stabilizes Fe-rich bridgmanite such that we were able to synthesize pure iron bridgmanite at pressures between ~45 and 110 GPa. The compressibility of ferric iron–bearing bridgmanite is significantly different from any known bridgmanite, which has direct implications for the interpretation of seismic tomography data. PMID:27453945

  19. MicroRNA regulation of F-box proteins and its role in cancer.

    PubMed

    Wu, Zhao-Hui; Pfeffer, Lawrence M

    2016-02-01

    MicroRNAs (miRNAs) are small endogenous non-coding RNAs, which play critical roles in cancer development by suppressing gene expression at the post-transcriptional level. In general, oncogenic miRNAs are upregulated in cancer, while miRNAs that act as tumor suppressors are downregulated, leading to decreased expression of tumor suppressors and upregulated oncogene expression, respectively. F-box proteins function as the substrate-recognition components of the SKP1-CUL1-F-box (SCF)-ubiquitin ligase complex for the degradation of their protein targets by the ubiquitin-proteasome system. Therefore F-box proteins and miRNAs both negatively regulate target gene expression post-transcriptionally. Since each miRNA is capable of fine-tuning the expression of multiple target genes, multiple F-box proteins may be suppressed by the same miRNA. Meanwhile, one F-box proteins could be regulated by several miRNAs in different cancer types. In this review, we will focus on miRNA-mediated downregulation of various F-box proteins, the resulting stabilization of F-box protein substrates and the impact of these processes on human malignancies. We provide insight into how the miRNA: F-box protein axis may regulate cancer progression and metastasis. We also consider the broader role of F-box proteins in the regulation of pathways that are independent of the ubiquitin ligase complex and how that impacts on oncogenesis. The area of miRNAs and the F-box proteins that they regulate in cancer is an emerging field and will inform new strategies in cancer treatment.

  20. The Human Mitochondrial DEAD-Box Protein DDX28 Resides in RNA Granules and Functions in Mitoribosome Assembly

    PubMed Central

    Tu, Ya-Ting; Barrientos, Antoni

    2015-01-01

    SUMMARY Human mitochondrial ribosomes are specialized in the synthesis of 13 proteins, which are fundamental components of the oxidative phosphorylation system. The pathway of mitoribosome biogenesis, the compartmentalization of the process and factors involved remain largely unknown. Here, we have identified the DEAD box protein DDX28 as an RNA granule component essential for the biogenesis of the mitoribosome large subunit (mt-LSU). DDX28 interacts with the 16S rRNA and the mt-LSU. RNAi-mediated DDX28 silencing in HEK293T cells does not affect mitochondrial mRNA stability, 16S rRNA processing or modification. However, it leads to reduced levels of 16S rRNA and mt-LSU proteins, impaired mt-LSU assembly, deeply attenuated mitochondrial protein synthesis and consequent failure to assemble oxidative phosphorylation complexes. Our findings identify DDX28 as essential during the early stages of mitoribosome mt-LSU biogenesis, a process that mainly takes place near the mitochondrial nucleoids, in the compartment defined by the RNA granules. PMID:25683708

  1. The Lithium Vapor Box Divertor

    NASA Astrophysics Data System (ADS)

    Goldston, Robert; Hakim, Ammar; Hammett, Gregory; Jaworski, Michael; Myers, Rachel; Schwartz, Jacob

    2015-11-01

    Projections of scrape-off layer width to a demonstration power plant suggest an immense parallel heat flux, of order 12 GW/m2, which will necessitate nearly fully detached operation. Building on earlier work by Nagayama et al. and by Ono et al., we propose to use a series of differentially pumped boxes filled with lithium vapor to isolate the buffering vapor from the main plasma chamber, allowing stable detachment. This powerful differential pumping is only available for condensable vapors, not conventional gases. We demonstrate the properties of such a system through conservation laws for vapor mass and enthalpy, and then include plasma entrainment and ultimately an estimate of radiated power. We find that full detachment should be achievable with little leakage of lithium to the main plasma chamber. We also present progress towards solving the Navier-Stokes equation numerically for the chain of vapor boxes, including self-consistent wall boundary conditions and fully-developed shocks, as well as concepts for an initial experimental demonstration-of-concept. This work supported by DOE Contract No. DE-AC02-09CH11466.

  2. Box graphs and singular fibers

    NASA Astrophysics Data System (ADS)

    Hayashi, Hirotaka; Lawrie, Craig; Morrison, David R.; Schafer-Nameki, Sakura

    2014-05-01

    We determine the higher codimension fibers of elliptically fibered Calabi-Yau fourfolds with section by studying the three-dimensional = 2 supersymmetric gauge theory with matter which describes the low energy effective theory of M-theory compactified on the associated Weierstrass model, a singular model of the fourfold. Each phase of the Coulomb branch of this theory corresponds to a particular resolution of the Weierstrass model, and we show that these have a concise description in terms of decorated box graphs based on the representation graph of the matter multiplets, or alternatively by a class of convex paths on said graph. Transitions between phases have a simple interpretation as "flopping" of the path, and in the geometry correspond to actual flop transitions. This description of the phases enables us to enumerate and determine the entire network between them, with various matter representations for all reductive Lie groups. Furthermore, we observe that each network of phases carries the structure of a (quasi-)minuscule representation of a specific Lie algebra. Interpreted from a geometric point of view, this analysis determines the generators of the cone of effective curves as well as the network of flop transitions between crepant resolutions of singular elliptic Calabi-Yau fourfolds. From the box graphs we determine all fiber types in codimensions two and three, and we find new, non-Kodaira, fiber types for E 6, E7 and E 8.

  3. Template-Assisted Synthesis of Nickel Sulfide Nanowires: Tuning the Compositions for Supercapacitors with Improved Electrochemical Stability.

    PubMed

    Zang, Xiaoxian; Dai, Ziyang; Yang, Jun; Zhang, Yizhou; Huang, Wei; Dong, Xiaochen

    2016-09-21

    Ni nanowires were first synthesized via a chemical method without surfactants or a magnetic field. A series of nickel sulfide nanowires (Ni3S2-Ni, Ni3S2-NiS-Ni, and Ni3S2-NiS) have been successfully prepared by a controlled sacrificial template route based on the conductive Ni nanowire template. Electrochemical characterizations indicate that Ni3S2-NiS nanowires present superior redox reactivity with a high specific capacitance of 1077.3 F g(-1) at 5 A g(-1). Besides, its specific capacitance can remain about 76.3% after 10 000 cycles at 20 A g(-1). On the contrary, the nickel-preserving sulfide nanowires (Ni3S2-Ni and Ni3S2-NiS-Ni) deliver enhanced cycling stability as 100% of the initial specific capacitance of Ni3S2-Ni is retained after 10 000 cycles. The outstanding electrochemical stability can be attributed to the interaction between nickel sulfides and the conductive nickel nanowires. PMID:27584060

  4. Enzymatic Synthesis of l-Ascorbyl Fatty Acid Esters Under Ultrasonic Irradiation and Comparison of Their Antioxidant Activity and Stability.

    PubMed

    Jiang, Chen; Lu, Yuyun; Li, Zhuo; Li, Cunzhi; Yan, Rian

    2016-06-01

    A series of novel l-ascorbyl fatty acid esters were synthesized by catalization of Novozym(®) 435 under ultrasonic irradiation and characterized by infrared spectroscopy, electrospray ionization mass spectra, and nuclear magnetic resonance. Their properties especially antioxidant activity and stability were investigated. The results showed that the reducing power, the scavenging activity of hydroxyl radical and 2,2-diphenyl-1-picrylhydrazyl radical were decreased with the increase of the number of carbon atoms in fatty acid. The hydroxyl radical scavenging activity and reducing power of l-ascorbyl saturated fatty acid esters were better than that of tert-butylhydroquinone. The induction period in lipid oxidation of l-ascorbyl saturated fatty acid esters and tert-butylhydroquinone were longer than that of l-ascorbyl unsaturated fatty acid esters and l-ascorbic acid both in soybean oil and lard. Besides, the l-ascorbyl fatty acid esters showed different stabilities in different conditions by comparing with l-ascorbic acid, and the l-ascorbyl saturated fatty acid esters were more stable than l-ascorbyl unsaturated fatty acid esters in ethanol solution. PMID:27100741

  5. Hydrothermal synthesis of superparamagnetic Fe{sub 3}O{sub 4} nanoparticles with ionic liquids as stabilizer

    SciTech Connect

    Liu, Xiao-Di Chen, Hao; Liu, Shan-Shan; Ye, Li-Qun; Li, Yin-Ping

    2015-02-15

    Highlights: • Superparamagnetic Fe{sub 3}O{sub 4} nanoparticles with good dispersity have been synthesized via hydrothermal method. • Ionic liquid [C{sub 16}mim]Cl acts as stabilizer for the Fe{sub 3}O{sub 4} nanoparticles. • Fe{sub 3}O{sub 4} nanoparticles have a saturation magnetization of 67.69 emu/g at 300 K. - Abstract: Superparamagnetic Fe{sub 3}O{sub 4} nanoparticles have been successfully synthesized under hydrothermal condition with the assistant of ionic liquid 1-hexadecyl-3-methylimidazolium chloride ([C{sub 16}mim]Cl). The structure and morphology of the sample have been investigated by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM), and the results indicate that the as-synthesized inverse spinel Fe{sub 3}O{sub 4} nanoparticles have an average diameter of about 10 nm and exhibit relatively good dispersity. More importantly, it is found that [C{sub 16}mim]Cl acts as stabilizer for the Fe{sub 3}O{sub 4} nanoparticles by adsorbing on the particles surfaces to prevent the agglomeration. In addition, the obtained superparamagnetic Fe{sub 3}O{sub 4} nanoparticles have a saturation magnetization of 67.69 emu/g at 300 K.

  6. Synthesis of silver nanoparticles on reduced graphene oxide under microwave irradiation with starch as an ideal reductant and stabilizer

    NASA Astrophysics Data System (ADS)

    Han, Yujie; Luo, Zhimin; Yuwen, Lihui; Tian, Jing; Zhu, Xingrong; Wang, Lianhui

    2013-02-01

    A facile aqueous solution procedure has been developed to synthesize silver nanoparticles (Ag NPs) on reduced graphene oxide (RGO) (RGO/Ag NPs) with starch as an ideal reductant and stabilizer in one pot under microwave irradiation. Graphene oxide and Ag(NH3)2+ were reduced simultaneously by starch in the process of forming Ag NPs. The size of Ag NPs decorated on the RGO sheets is about 20-50 nm and the average size of Ag NPs on RGO is 34 nm calculated by X-ray diffraction. RGO and RGO/Ag NPs prepared with starch show good stability in aqueous solution. With the decoration of Ag NPs on RGO, Raman intensity of RGO increased evidently. Antimicrobial activity of RGO/Ag NPs was investigated against the gram negative bacteria Pseudomonous aeruginosa. The minimum inhibitory concentration (MIC) of RGO/Ag NPs is 0.2 wt%. The antimicrobial activity of RGO/Ag NPs is stronger than Ag NPs because of the synergic effect of RGO and Ag NPs.

  7. Synthesis, Structure, and Reactivities of Iminosulfane- and Phosphane-Stabilized Carbones Exhibiting Four-Electron Donor Ability.

    PubMed

    Morosaki, Tomohito; Wang, Wei-Wei; Nagase, Shigeru; Fujii, Takayoshi

    2015-10-19

    Iminosulfane(phosphane)carbon(0) derivatives (iSPCs; Ar3 P→C←SPh2 (NMe); Ar=Ph (1), 4-MeOC6 H4 (2), 4-(Me2 N)C6 H4 (3)) have been successfully synthesized and the molecular structure of 3 characterized. Carbone 3 is the first thermally and hydrolytically stable carbone stabilized by phosphorus and sulfur ligands. DFT calculations reveal the electronic structures of 1-3, which have two lone pairs of electrons at the carbon center. First and second proton affinity values are theoretically calculated to be in the range of 286.8-301.1 and 189.6-208.3 kcal mol(-1) , respectively. Cyclic voltammetry measurements reveal that the HOMO energy levels follow the order of 3>2>1 and the HOMO of 3 is at a higher energy than those of bis(chalcogenane)carbon(0) (BChCs). The reactivities of these lone pairs of electrons are demonstrated by the C-diaurated and C-proton-aurated complexes. These results are the first experimental evidence of phosphorus- and sulfur-stabilized carbones behaving as four-electron donors. In addition, the reaction of hydrochloric salts of the carbones with Ag2 O gives the corresponding Ag(I) complexes. The resulting silver(I) carbone complexes can be used as carbone transfer agents. This synthetic protocol can also be used for moisture-sensitive carbone species. PMID:26471447

  8. Facile synthesis of pectin-stabilized magnetic graphene oxide Prussian blue nanocomposites for selective cesium removal from aqueous solution.

    PubMed

    Kadam, Avinash A; Jang, Jiseon; Lee, Dae Sung

    2016-09-01

    This work focused on the development of pectin-stabilized magnetic graphene oxide Prussian blue (PSMGPB) nanocomposites for removal of cesium from wastewater. The PSMGPB nanocomposite showed an improved adsorption capacity of 1.609mmol/g for cesium, compared with magnetic graphene oxide Prussian blue, magnetic pectin Prussian blue, and magnetic Prussian blue nanocomposites, which exhibited adsorption capacities of 1.230, 0.901, and 0.330mmol/g, respectively. Increased adsorption capacity of PSMGPB nanocomposites was attributed to the pectin-stabilized separation of graphene oxide sheets and enhanced distribution of magnetites on the graphene oxide surface. Scanning electron microscopy images showed the effective separation of graphene oxide sheets due to the incorporation of pectin. The optimum temperature and pH for adsorption were 30°C and 7.0, respectively. A thermodynamic study indicated the spontaneous and the exothermic nature of cesium adsorption. Based on non-linear regression, the Langmuir isotherm fitted the experimental data better than the Freundlich and Tempkin models. PMID:27262093

  9. Microwave assisted synthesis of surfactant stabilized platinum/carbon nanotube electrocatalysts for direct methanol fuel cell applications

    NASA Astrophysics Data System (ADS)

    Sakthivel, M.; Schlange, A.; Kunz, U.; Turek, T.

    Platinum electrocatalysts deposited on multi-walled carbon nanotubes (CNT) with high loading were prepared using a microwave-assisted polyol reduction method and employed for direct methanol fuel cells (DMFC). A zwitterionic surfactant was used as a stabilizing agent for the formation of Pt nanoparticles. A uniform and narrow size distribution of highly dispersed Pt nanoparticles could be achieved by adjusting the weight ratio of surfactant to Pt precursor allowing for Pt loadings of up to 60 wt%. The heating time and the temperature for the ethylene glycol (EG) oxidation were found to be the key factors for depositing Pt nanoparticles homogeneously on carbon nanotubes. The smallest average particle diameter of 1.8 nm was obtained through microwave heating to 140 °C in 50 s. The structure, amount and morphology of the electrocatalysts were characterized with XRD, TGA, and TEM, respectively. Single cell DMFC measurements were performed in a membrane-electrode assembly (MEA) with 5 cm 2 active area and very low catalyst loading (0.25 mg cm -2 of noble metal on both anode and cathode). The DMFC performance of the surfactant stabilized cathode catalyst obtained by the new method described here revealed that the power density was three times higher than for a commercial catalyst used for comparison and two times higher than for an unstabilized CNT supported catalyst.

  10. Synthesis, Structure, and Reactivities of Iminosulfane- and Phosphane-Stabilized Carbones Exhibiting Four-Electron Donor Ability.

    PubMed

    Morosaki, Tomohito; Wang, Wei-Wei; Nagase, Shigeru; Fujii, Takayoshi

    2015-10-19

    Iminosulfane(phosphane)carbon(0) derivatives (iSPCs; Ar3 P→C←SPh2 (NMe); Ar=Ph (1), 4-MeOC6 H4 (2), 4-(Me2 N)C6 H4 (3)) have been successfully synthesized and the molecular structure of 3 characterized. Carbone 3 is the first thermally and hydrolytically stable carbone stabilized by phosphorus and sulfur ligands. DFT calculations reveal the electronic structures of 1-3, which have two lone pairs of electrons at the carbon center. First and second proton affinity values are theoretically calculated to be in the range of 286.8-301.1 and 189.6-208.3 kcal mol(-1) , respectively. Cyclic voltammetry measurements reveal that the HOMO energy levels follow the order of 3>2>1 and the HOMO of 3 is at a higher energy than those of bis(chalcogenane)carbon(0) (BChCs). The reactivities of these lone pairs of electrons are demonstrated by the C-diaurated and C-proton-aurated complexes. These results are the first experimental evidence of phosphorus- and sulfur-stabilized carbones behaving as four-electron donors. In addition, the reaction of hydrochloric salts of the carbones with Ag2 O gives the corresponding Ag(I) complexes. The resulting silver(I) carbone complexes can be used as carbone transfer agents. This synthetic protocol can also be used for moisture-sensitive carbone species.

  11. Template-Assisted Synthesis of Nickel Sulfide Nanowires: Tuning the Compositions for Supercapacitors with Improved Electrochemical Stability.

    PubMed

    Zang, Xiaoxian; Dai, Ziyang; Yang, Jun; Zhang, Yizhou; Huang, Wei; Dong, Xiaochen

    2016-09-21

    Ni nanowires were first synthesized via a chemical method without surfactants or a magnetic field. A series of nickel sulfide nanowires (Ni3S2-Ni, Ni3S2-NiS-Ni, and Ni3S2-NiS) have been successfully prepared by a controlled sacrificial template route based on the conductive Ni nanowire template. Electrochemical characterizations indicate that Ni3S2-NiS nanowires present superior redox reactivity with a high specific capacitance of 1077.3 F g(-1) at 5 A g(-1). Besides, its specific capacitance can remain about 76.3% after 10 000 cycles at 20 A g(-1). On the contrary, the nickel-preserving sulfide nanowires (Ni3S2-Ni and Ni3S2-NiS-Ni) deliver enhanced cycling stability as 100% of the initial specific capacitance of Ni3S2-Ni is retained after 10 000 cycles. The outstanding electrochemical stability can be attributed to the interaction between nickel sulfides and the conductive nickel nanowires.

  12. Morphology-controlled hydrothermal synthesis of MnCO{sub 3} hierarchical superstructures with Schiff base as stabilizer

    SciTech Connect

    Hu, He; Xu, Jie-yan; Yang, Hong; Liang, Jie; Yang, Shiping; Wu, Huixia

    2011-11-15

    Graphical abstract: MnCO3 microcrystals with hierarchical superstructures were synthesized by using the CO2 in atmosphere as carbonate ions source and Schiff base as shape guiding-agent in water/ethanol system under hydrothermal condition. Highlights: {yields} The most interesting in this work is the use of the greenhouse gases CO{sub 2} in atmosphere as carbonate ions source to precipitate with Mn{sup 2+} for producing MnCO{sub 3} crystals. {yields} This work is the first report related to the small organic molecule Schiff base as shape guiding-agent to produce different MnCO{sub 3} hierarchical superstructures. {yields} We are controllable synthesis of the MnCO{sub 3} hierarchical superstructures such as chrysanthemum, straw-bundle, dumbbell and sphere-like microcrystals. {yields} The as-prepared MnCO{sub 3} could be used precursor to fabricate the Mn{sub 2}O{sub 3} hierarchical superstructures after thermal decomposition at high temperature. -- Abstract: MnCO{sub 3} with hierarchical superstructures such as chrysanthemum, straw-bundle, dumbbell and sphere-like were synthesized in water/ethanol system under environment-friendly hydrothermal condition. In the synthesis process, the CO{sub 2} in atmosphere was used as the source of carbonate ions and Schiff base was used as shape guiding-agent. The different superstructures of MnCO{sub 3} could be obtained by controlling the hydrothermal temperature, the molar ratio of manganous ions to the Schiff base, or the volume ratio of water to ethanol. A tentative growth mechanism for the generation of MnCO{sub 3} superstructures was proposed based on the rod-dumbbell-sphere model. Furthermore, the MnCO{sub 3} as precursor could be further successfully transferred to Mn{sub 2}O{sub 3} microstructure after heating in the atmosphere at 500 {sup o}C, and the morphology of the Mn{sub 2}O{sub 3} was directly determined by that of the MnCO{sub 3} precursor.

  13. Palladium complexes of a phosphorus ylide with two stabilizing groups: synthesis, structure, and DFT study of the bonding modes.

    PubMed

    Falvello, Larry R; Ginés, Juan Carlos; Carbó, Jorge J; Lledós, Agustí; Navarro, Rafael; Soler, Tatiana; Urriolabeitia, Esteban P

    2006-08-21

    The phosphorus ylide ligand [Ph3P=C(CO2Me)C(=NPh)CO2Me] (L1) has been prepared and fully characterized by spectroscopic, crystallographic, and density functional theory (DFT) methods (B3LYP level). The reactivity of L1 toward several cationic Pd(II) and Pt(II) precursors, with two vacant coordination sites, has been studied. The reaction of [M(C/\\X)(THF)2]ClO4 with L1 (1:1 molar ratio) gives [M(C/\\X)(L1)]ClO4 [M = Pd, C/\\X = C6H4CH2NMe2 (1), S-C6H4C(H)MeNMe2 (2), CH2-8-C9H6N (3), C6H4-2-NC5H4 (4), o-CH2C6H4P(o-tol)2 (6), eta3-C3H5 (7); M = Pt, C/\\X = o-CH2C6H4P(o-tol)2 (5); M(C/\\X) = Pd(C6F5)(SC4H8) (8), PdCl2 (9)]. In complexes 1-9, the ligand L1 bonds systematically to the metal center through the iminic N and the carbonyl O of the stabilizing CO2Me group, as is evident from the NMR data and from the X-ray structure of 3. Ligand L1 can also be orthopalladated by reaction with Pd(OAc)2 and LiCl, giving the dinuclear derivative [Pd(mu-Cl)(C6H4-2-PPh2=C(CO2Me)C(CO2Me)=NPh)]2 (10). The X-ray crystal structure of 10 is also reported. In none of the prepared complexes 1-10 was the C(alpha) atom found to be bonded to the metal center. DFT calculations and Bader analysis were performed on ylide L1 and complex 9 and its congeners in order to assess the preference of the six-membered N,O metallacycle over the four-membered C,N and five-membered C,O rings. The presence of two stabilizing groups at the ylidic C causes a reduction of its bonding capabilities. The increasing strength of the Pd-C, Pd-O, and Pd-N bonds along with other subtle effects are responsible for the relative stabilities of the different bonding modes. PMID:16903737

  14. Interchangeable breech lock for glove boxes

    SciTech Connect

    Lemonds, David Preston

    2015-11-24

    A breech lock for a glove box is provided that may be used to transfer one or more items into the glove box. The breech lock can be interchangeably installed in place of a plug, glove, or other device in a port or opening of a glove box. Features are provided to aid the removal of items from the breech lock by a gloved operator. The breech lock can be reused or, if needed, can be replaced with a plug, glove, or other device at the port or opening of the glove box.

  15. Repackaging SRS Black Box TRU Waste

    SciTech Connect

    Swale, D. J.; Stone, K.A.; Milner, T. N.

    2006-01-09

    Historically, large items of TRU Waste, which were too large to be packaged in drums for disposal have been packaged in various sizes of custom made plywood boxes at the Savannah River Site (SRS), for many years. These boxes were subsequently packaged into large steel ''Black Boxes'' for storage at SRS, pending availability of Characterization and Certification capability, to facilitate disposal of larger items of TRU Waste. There are approximately 107 Black Boxes in inventory at SRS, each measuring some 18' x 12' x 7', and weighing up to 45,000 lbs. These Black Boxes have been stored since the early 1980s. The project to repackage this waste into Standard Large Boxes (SLBs), Standard Waste Boxes (SWB) and Ten Drum Overpacks (TDOP), for subsequent characterization and WIPP disposal, commenced in FY04. To date, 10 Black Boxes have been repackaged, resulting in 40 SLB-2's, and 37 B25 overpack boxes, these B25's will be overpacked in SLB-2's prior to shipping to WIPP. This paper will describe experience to date from this project.

  16. Synthesis, thermal stability and reactivity towards 9-aminoellipticine of double-stranded oligonucleotides containing a true abasic site.

    PubMed Central

    Bertrand, J R; Vasseur, J J; Rayner, B; Imbach, J L; Paoletti, J; Paoletti, C; Malvy, C

    1989-01-01

    A 13 mers abasic oligonucleotide was synthetized. It was therefore possible to compare thermal stability and reactivity of duplex oligonucleotides either with an apurinic/apyrimidinic site or without any lesion. An important decrease in the melting temperature appeared for duplexes with an abasic site. The chemical reaction of these modified oligonucleotides with the intercalating agent 9-aminoellipticine was studied by gel electrophoresis and by fluorescence. The formation of a Schiff base between 9-aminoellipticine and abasic sites was rapid and complete with duplexes at 11 degrees C. Schiff base related fluorescence and beta-elimination cleavage were more important with the apyrimidinic sites than with the apurinic ones. When compared to previous results obtained with the model d(TprpT) some unexpected behaviours appeared with longer and duplex oligonucleotides. For instance only partial beta-elimination cleavage was observed. It is likely that stacking parameters in the double helix play a great role in the studied reaction. Images PMID:2602153

  17. Synthesis and thermal stability studies of a series of metastable Dion-Jacobson double-layered neodymium-niobate perovskites

    NASA Astrophysics Data System (ADS)

    Josepha, Elisha A.; Farooq, Sara; Mitchell, Cinnamon M.; Wiley, John B.

    2014-08-01

    The Dion-Jacobson double-layered perovskite, RbNdNb2O7, is used as a precursor to synthesize the series ANdNb2O7 (A=H, Li, Na, K, NH4, Ag), and (MCl)NdNb2O7 (M=Mn, Fe, Cu) through ion-exchange reactions ≤400 °C. Thermal stability studies indicated that most of these compounds are metastable. A combination of X-ray powder diffraction and differential thermal analysis were used to determine various low temperature decomposition pathways; these pathways were very dependent on the interlayer species. Overall the ANdNb2O7 series was found to be less stable than the corresponding lanthanides, ALaNb2O7.

  18. Effect of stabilizers on the synthesis of palladium-nickel nanoparticles supported on carbon for ethanol oxidation in alkaline medium

    NASA Astrophysics Data System (ADS)

    Yang, Huijuan; Wang, Hui; Li, Hao; Ji, Shan; Davids, Moegamat Wafeeq; Wang, Rongfang

    2014-08-01

    PdNi/C electrocatalysts for ethanol oxidation in alkaline medium are fabricated using four stabilizers, i.e., glycine (G), ethylene diamine tetraacetic acid (EDTA), sodium citrate (SC), and sodium dodecyl sulfate (SDS) with the same reducing process and reaction parameters. X-ray diffraction characterization shows PdNi nanoparticles for all PdNi/C electrocatalysts possess face-centered cubic structure with different alloying degree. TEM results show that PdNi/C-G and PdNi/C-SC have uniform dispersion with ellipse morphology, while particle agglomeration occurs on PdNi/C-EDTA and PdNi/C-SDS. Electrocatalytic activities of these PdNi/C electrocatalysts for ethanol oxidation are measured by cyclic voltammetry and chronoamperometry techniques. The electrocatalytic activities of PdNi/C change with the different lattice contraction. PdNi/C-SC electrocatalyst exhibits the best activity among the four electrocatalysts, which is ascribed to an appropriate lattice contraction.

  19. A 2,2"-bipyridine ligand for incorporation into oligodeoxynucleotides: synthesis, stability and fluorescence properties of ruthenium-DNA complexes.

    PubMed

    Wiederholt, K; McLaughlin, L W

    1999-06-15

    A non-nucleoside linker based upon the ligand 2,2'-bipyridine and ethylene glycol is prepared and placed into the backbone of a number of oligonucleo-tides. The bipyridine ligand is reacted with cis -dichloro bis(2,2'-bipyridyl) Ru(II) to generate the relatively substitutionally inert complex based upon the well-characterized tris -2,2'-bipyridyl Ru(II). The ruthenium-containing DNA complexes exhibited UV and fluorescence characteristics that are consistent with those previously observed for simple tris -2,2'-bipyridyl Ru(II) complexes. Oligonucleotides containing the ruthenium complex will form both DNA duplexes and triplexes with stabilities that are slightly better than those formed from simple tethered oligonucleotide probes in which the two hybridizing sequences are tethered by simple tri(ethylene glycol) or hexa(ethylene glycol) linkers.

  20. Bacillus subtilis glutamine synthetase regulates its own synthesis by acting as a chaperone to stabilize GlnR-DNA complexes.

    PubMed

    Fisher, Susan H; Wray, Lewis V

    2008-01-22

    The Bacillus subtilis GlnR repressor controls gene expression in response to nitrogen availability. Because all GlnR-regulated genes are expressed constitutively in mutants lacking glutamine synthetase (GS), GS is required for repression by GlnR. Feedback-inhibited GS (FBI-GS) was shown to activate GlnR DNA binding with an in vitro electophoretic mobility shift assay (EMSA). The activation of GlnR DNA binding by GS in these experiments depended on the feedback inhibitor glutamine and did not occur with mutant GS proteins defective in regulating GlnR activity in vivo. Although stable GS-GlnR-DNA ternary complexes were not observed in the EMSA experiments, cross-linking experiments showed that a protein-protein interaction occurs between GlnR and FBI-GS. This interaction was reduced in the absence of the feedback inhibitor glutamine and with mutant GS proteins. Because FBI-GS significantly reduced the dissociation rate of the GlnR-DNA complexes, the stability of these complexes is enhanced by FBI-GS. These results argue that FBI-GS acts as a chaperone that activates GlnR DNA binding through a transient protein-protein interaction that stabilizes GlnR-DNA complexes. GS was shown to control the activity of the B. subtilis nitrogen transcription factor TnrA by forming a stable complex between FBI-GS and TnrA that inhibits TnrA DNA binding. Thus, B. subtilis GS is an enzyme with dual catalytic and regulatory functions that uses distinct mechanisms to control the activity of two different transcription factors.

  1. Microwave-assisted synthesis of phenanthroimidazole derivatives as stabilizer of c-myc G-quadruplex DNA.

    PubMed

    Liao, Siyan; Zhang, Zhao; Wu, Qiong; Wang, Xicheng; Mei, Wenjie

    2014-11-15

    c-myc G-quadruplex DNA, which plays a central role in tumor progression and resistance, has been extensively investigated as potential target of antitumor drugs. In this paper, a series of phenanthroimidazole derives have been synthesized under irradiation of microwave in yields of 51–80%. The antitumor activity of these compounds against various tumor cells has been evaluated, and the results show that these compounds exhibit great inhibition to MDA-MB-231, MCF-7 and Hela cells, especially 5 inhibit the growth of MDA-MB-231 cells with IC50 about 3.6 lM. The further studies show that 5 can bind and stabilize c-myc G4 DNA in p–p stacking mode, which confirmed by the hypochromise in the electronic spectra of 5 with the increasing of c-myc G4 DNA. When dealt with 5, the strength of CD signal attributed to c-myc G4 DNA is decreased and the FRET melting point of c-myc G4 DNA is increased. Moreover, the molecule docking calculation was conducted to show that 5 suitably stack onto the 50 G-quartet surface, and parallels to the surfaces of the G5 and G-quartet consisting of G7, G11, G16, and G20. As a result, the replication of c-myc oligomers is blocked by 5. In a word, this type of phenanthroimidazole derives can act as potential inhibitor against breast cancer cells by binding and stabilizing c-myc G4 DNA through p–p stacking.

  2. Structural Basis of Thermal Stability of the Tungsten Cofactor Synthesis Protein MoaB from Pyrococcus furiosus

    PubMed Central

    Havarushka, Nastassia; Fischer-Schrader, Katrin; Lamkemeyer, Tobias; Schwarz, Guenter

    2014-01-01

    Molybdenum and tungsten cofactors share a similar pterin-based scaffold, which hosts an ene-dithiolate function being essential for the coordination of either molybdenum or tungsten. The biosynthesis of both cofactors involves a multistep pathway, which ends with the activation of the metal binding pterin (MPT) by adenylylation before the respective metal is incorporated. In the hyperthermophilic organism Pyrococcus furiosus, the hexameric protein MoaB (PfuMoaB) has been shown to catalyse MPT-adenylylation. Here we determined the crystal structure of PfuMoaB at 2.5 Å resolution and identified key residues of α3-helix mediating hexamer formation. Given that PfuMoaB homologues from mesophilic organisms form trimers, we investigated the impact on PfuMoaB hexamerization on thermal stability and activity. Using structure-guided mutagenesis, we successfully disrupted the hexamer interface in PfuMoaB. The resulting PfuMoaB-H3 variant formed monomers, dimers and trimers as determined by size exclusion chromatography. Circular dichroism spectroscopy as well as chemical cross-linking coupled to mass spectrometry confirmed a wild-type-like fold of the protomers as well as inter-subunits contacts. The melting temperature of PfuMoaB-H3 was found to be reduced by more than 15°C as determined by differential scanning calorimetry, thus demonstrating hexamerization as key determinant for PfuMoaB thermal stability. Remarkably, while a loss of activity at temperatures higher than 50°C was observed in the PfuMoaB-H3 variant, at lower temperatures, we determined a significantly increased catalytic activity. The latter suggests a gain in conformational flexibility caused by the disruption of the hexamerization interface. PMID:24465852

  3. Structural basis of thermal stability of the tungsten cofactor synthesis protein MoaB from Pyrococcus furiosus.

    PubMed

    Havarushka, Nastassia; Fischer-Schrader, Katrin; Lamkemeyer, Tobias; Schwarz, Guenter

    2014-01-01

    Molybdenum and tungsten cofactors share a similar pterin-based scaffold, which hosts an ene-dithiolate function being essential for the coordination of either molybdenum or tungsten. The biosynthesis of both cofactors involves a multistep pathway, which ends with the activation of the metal binding pterin (MPT) by adenylylation before the respective metal is incorporated. In the hyperthermophilic organism Pyrococcus furiosus, the hexameric protein MoaB (PfuMoaB) has been shown to catalyse MPT-adenylylation. Here we determined the crystal structure of PfuMoaB at 2.5 Å resolution and identified key residues of α3-helix mediating hexamer formation. Given that PfuMoaB homologues from mesophilic organisms form trimers, we investigated the impact on PfuMoaB hexamerization on thermal stability and activity. Using structure-guided mutagenesis, we successfully disrupted the hexamer interface in PfuMoaB. The resulting PfuMoaB-H3 variant formed monomers, dimers and trimers as determined by size exclusion chromatography. Circular dichroism spectroscopy as well as chemical cross-linking coupled to mass spectrometry confirmed a wild-type-like fold of the protomers as well as inter-subunits contacts. The melting temperature of PfuMoaB-H3 was found to be reduced by more than 15 °C as determined by differential scanning calorimetry, thus demonstrating hexamerization as key determinant for PfuMoaB thermal stability. Remarkably, while a loss of activity at temperatures higher than 50 °C was observed in the PfuMoaB-H3 variant, at lower temperatures, we determined a significantly increased catalytic activity. The latter suggests a gain in conformational flexibility caused by the disruption of the hexamerization interface. PMID:24465852

  4. H3PW12O40 Encapsulation by Nanoporous Metal Organic Framework HKUST-1: Synthesis, Characterization, Activity and Stability.

    PubMed

    Rafiee, Ezzat; Nobakht, Narges

    2016-01-01

    Hybrid composite material was obtained through encapsulation of H3PW12O40 (PW) into HKUST-1 (Cu3(BTC)2, BTC = 1,3,5-benzenetricarboxylic acid), in molar composition of 5 Cu(NO3)2 · 3H2O/2.8 BTC/0.3 PW/0.6 CTAB by adding solutions of PW and copper salts to mixture of BTC and surfactant. The catalyst was characterized by various techniques including powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), laser particle size analyzer, Brunauer Emmett-Teller (BET). The acidity of the catalyst was measured by a potentiometric titration with n-butylamine and PW/HKUST-1 presented very strong acidic sites with Ei > 100 mV. This nano catalyst was successfully used for the synthesis of various β-keto enol ethers at 45 °C with 51-98% yield after 5-75 min. The catalyst was easily recycled and reused at least four times without significant loss of its activity (94% yield after forth run). The presence of the PW in PW/HKUST-1 and reused PW/HKUST-1 structure, eliminating any doubt about collapse of the HKUST-1 after catalytic reaction and can be followed by FT-IR, XRD and SEM techniques. Brönsted and Lewis acidity of the PW/HKUST-1 catalyst was distinguished by studying the FT-IR and determined by chemisorption of pyridine. The strength and dispersion of the protons on PW/HKUST-1 was considerably high and active surface protons became more available for reactant.

  5. H3PW12O40 Encapsulation by Nanoporous Metal Organic Framework HKUST-1: Synthesis, Characterization, Activity and Stability.

    PubMed

    Rafiee, Ezzat; Nobakht, Narges

    2016-01-01

    Hybrid composite material was obtained through encapsulation of H3PW12O40 (PW) into HKUST-1 (Cu3(BTC)2, BTC = 1,3,5-benzenetricarboxylic acid), in molar composition of 5 Cu(NO3)2 · 3H2O/2.8 BTC/0.3 PW/0.6 CTAB by adding solutions of PW and copper salts to mixture of BTC and surfactant. The catalyst was characterized by various techniques including powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), laser particle size analyzer, Brunauer Emmett-Teller (BET). The acidity of the catalyst was measured by a potentiometric titration with n-butylamine and PW/HKUST-1 presented very strong acidic sites with Ei > 100 mV. This nano catalyst was successfully used for the synthesis of various β-keto enol ethers at 45 °C with 51-98% yield after 5-75 min. The catalyst was easily recycled and reused at least four times without significant loss of its activity (94% yield after forth run). The presence of the PW in PW/HKUST-1 and reused PW/HKUST-1 structure, eliminating any doubt about collapse of the HKUST-1 after catalytic reaction and can be followed by FT-IR, XRD and SEM techniques. Brönsted and Lewis acidity of the PW/HKUST-1 catalyst was distinguished by studying the FT-IR and determined by chemisorption of pyridine. The strength and dispersion of the protons on PW/HKUST-1 was considerably high and active surface protons became more available for reactant. PMID:27333553

  6. Myc-Max heterodimers activate a DEAD box gene and interact with multiple E box-related sites in vivo.

    PubMed

    Grandori, C; Mac, J; Siëbelt, F; Ayer, D E; Eisenman, R N

    1996-08-15

    The c-Myc protein is involved in cell proliferation, differentiation and apoptosis though heterodimerization with Max to form a transcriptionally active sequence-specific DNA binding complex. By means of sequential immunoprecipitation of chromatin using anti-Max and anti-Myc antibodies, we have identified a Myc-regulated gene and genomic sites occupied by Myc-Max in vivo. Four of 27 sites recovered by this procedure corresponded to the highest affinity 'canonical' CACGTG sequence. However, the most common in vivo binding sites belonged to the group of 'non-canonical' E box-related binding sites previously identified by in vitro selection. Several of the genomic fragments isolated contained transcribed sequences, including one, MrDb, encoding an evolutionarily conserved RNA helicase of the DEAD box family. The corresponding mRNA was induced following activation of a Myc-estrogen receptor fusion protein (Myc-ER) in the presence of a protein synthesis inhibitor, consistent with this helicase gene being a direct target of Myc-Max. In addition, as for c-Myc, the expression of MrDb is induced upon proliferative stimulation of primary human fibroblasts as well as B cells and down-regulated during terminal differentiation of HL60 leukemia cells. Our results indicate that Myc-Max heterodimers interact in vivo with a specific set of E box-related DNA sequences and that Myc is likely to activate multiple target genes including a highly conserved DEAD box protein. Therefore, Myc may exert its effects on cell behavior through proteins that affect RNA structure and metabolism.

  7. Role of Hydroxytyrosol-dependent Regulation of HO-1 Expression in Promoting Wound Healing of Vascular Endothelial Cells via Nrf2 De Novo Synthesis and Stabilization.

    PubMed

    Zrelli, Houda; Kusunoki, Miki; Miyazaki, Hitoshi

    2015-07-01

    Hydroxytyrosol (HT), an olive plant (Olea europaea L.) polyphenol, has proven atheroprotective effects. We previously demonstrated that heme oxygenase-1 (HO-1) is involved in the HT dependent prevention of dysfunction induced by oxidative stress in vascular endothelial cells (VECs). Here, we further investigated the signaling pathway of HT-dependent HO-1 expression in VECs. HT dose- and time-dependently increased HO-1 mRNA and protein levels through the PI3K/Akt and ERK1/2 pathways. Cycloheximide and actinomycin D inhibited both increases, suggesting that HT-triggered HO-1 induction is transcriptionally regulated and that de novo protein synthesis is necessary for this HT effect. HT stimulated nuclear accumulation of nuclear factor E2-related factor 2 (Nrf2). This Nrf2 accumulation was blocked by actinomycin D and cycloheximide whereas HT in combination with the 26S proteasome inhibitor MG132 enhanced the accumulation. HT also extended the half-life of Nrf2 proteins by decelerating its turnover. Moreover, HO-1 inhibitor, ZnppIX and CO scavenger, hemoglobin impaired HT-dependent wound healing while CORM-2, a CO generator, accelerated wound closure. Together, these data demonstrate that HT upregulates HO-1 expression by stimulating the nuclear accumulation and stabilization of Nrf2, leading to the wound repair of VECs crucial in the prevention of atherosclerosis.

  8. Facile synthesis of near infrared fluorescent trypsin-stabilized Ag nanoclusters with tunable emission for 1,4-dihydronicotinamide adenine dinucleotide and ethanol sensing.

    PubMed

    Liu, Siyu; Wang, Hui; Cheng, Zhen; Liu, Hongguang

    2015-07-30

    A facile chemical synthetic route was developed to prepare near-infrared fluorescent trypsin-stabilized Ag nanoclusters (Try-Ag NCs). The fluorescence emission wavelength of the produced Try-Ag NCs is tunable by simple adjusting pH value of the synthesis system, and the Try-Ag NCs offer a symmetric fluorescent excitation and emission peak. The fluorescence of Try-Ag NCs remains constant in the presence of various ions and molecules, and it can be effectively quenched by 1,4-dihydronicotinamide adenine dinucleotide (NADH) instead of its oxidized forms nicotinamide adenine dinucleotide (NAD(+)). This property enables the Try-Ag NCs to be a novel analytical platform to monitor biological reaction involved with NADH. In this work, the Try-Ag NCs was also applied to analyze ethanol based on the generation of NADH which was the product of NAD(+) and ethanol in the catalysis of alcohol dehydrogenase. And the proposed platform allowed ethanol to be determined in the range from 10 to 300 μmol/L with 5 μmol/L detection limit.

  9. Comparison of Proteins Involved in Pilus Synthesis and Mating Pair Stabilization from the Related Plasmids F and R100-1: Insights into the Mechanism of Conjugation

    PubMed Central

    Anthony, Karen G.; Klimke, William A.; Manchak, Jan; Frost, Laura S.

    1999-01-01

    F and R100-1 are closely related, derepressed, conjugative plasmids from the IncFI and IncFII incompatibility groups, respectively. Heteroduplex mapping and genetic analyses have revealed that the transfer regions are extremely similar between the two plasmids. Plasmid specificity can occur at the level of relaxosome formation, regulation, and surface exclusion between the two transfer systems. There are also differences in pilus serology, pilus-specific phage sensitivity, and requirements for OmpA and lipopolysaccharide components in the recipient cell. These phenotypic differences were exploited in this study to yield new information about the mechanism of pilus synthesis, mating pair stabilization, and surface and/or entry exclusion, which are collectively involved in mating pair formation (Mpf). The sequence of the remainder of the transfer region of R100-1 (trbA to traS) has been completed, and the complete sequence is compared to that of F. The differences between the two transfer regions include insertions and deletions, gene duplications, and mosaicism within genes, although the genes essential for Mpf are conserved in both plasmids. F+ cells carrying defined mutations in each of the Mpf genes were complemented with the homologous genes from R100-1. Our results indicate that the specificity in recipient cell recognition and entry exclusion are mediated by TraN and TraG, respectively, and not by the pilus. PMID:10464182

  10. pH-regulative synthesis of Na3(VPO4)2F3 nanoflowers and their improved Na cycling stability

    DOE PAGES

    Qi, Yuruo; Mu, Linqin; Zhao, Junmei; Hu, Yong -Sheng; Liu, Huizhou; Dai, Sheng

    2016-04-08

    Na-ion batteries are becoming increasingly attractive as a low cost energy storage device. Sodium vanadium fluorophosphates have been studied extensively recently due to their high storage capacity and high discharge voltage. Shape and size often have a crucial influence over the properties. The controlling synthesis of nanoparticles with special microstructures is significant, which becomes a challenging issue and has drawn considerable attention. In this study, Na3(VPO4)2F3 nanoflowers have been synthesized via a pH-regulative low-temperature (120 °C) hydro-thermal route. In particular, it is a green route without any organic compounds involved. The hydro-thermal reaction time for the formation of Na3(VPO4)2F3 nanoflowersmore » has also been investigated. A weak acid environment (pH = 2.60) with the possible presence of hydrogen fluoride molecules is necessary for the formation of the desired nanoflower microstructures. Moreover, compared to the nanoparticles obtained by Na2HPO4·12H2O, the as-synthesized Na3(VPO4)2F3 nanoflowers showed an excellent Na-storage performance in terms of superior cycle stability, even without any further carbon coating or high-temperature treatment.« less

  11. Toward new organometallic architectures: synthesis of carbene-centered rhodium and palladium bisphosphine complexes. stability and reactivity of [PC(BIm)PRh(L)][PF6] pincers.

    PubMed

    Plikhta, Andriy; Pöthig, Alexander; Herdtweck, Eberhardt; Rieger, Bernhard

    2015-10-01

    In this article, we report the synthesis of a tridentate carbene-centered bisphosphine ligand precursor and its complexes. The developed four-step synthetic strategy of a new PC(BIm)P pincer ligand represents the derivatization of benzimidazole in the first and third positions by (diphenylphosphoryl)methylene synthone, followed by phosphine deprotection and subsequent insertion of a noncoordinating anion. The obtained ligand precursor undergoes complexation, with PdCl2 and [μ-OCH3Rh(COD)]2 smoothly forming the target organometallics [PC(BIm)PPdCl][PF6] and [PC(BIm)PRh(L)][PF6] under mild hydrogenation conditions. A more detailed study of the rhodium complexes [PC(BIm)PRh(L)][PF6] reveals significant thermal stability of the PC(BIm)PRh moiety in the solid state as well as in solution. The chemical behavior of 1,3-bis(diphenylphosphinomethylene)benzimidazol-2-ylrhodium acetonitrile hexafluorophosphate has been screened under decarbonylation, hydrogenation, and hydroboration reaction conditions. Thus, the PC(BIm)PRh(I) complex is a sufficiently stable compound, with the potential to be applied in catalysis.

  12. Novel microwave-synthesis of Cu nanoparticles in the absence of any stabilizing agent and their antibacterial and antistatic applications

    NASA Astrophysics Data System (ADS)

    Raspolli Galletti, Anna Maria; Antonetti, Claudia; Marracci, Mirko; Piccinelli, Fabio; Tellini, Bernardo

    2013-09-01

    For the first time, copper nanoparticles were synthesized under microwave (MW) irradiation in the absence of any stabilizing agent. A 2-step synthetic approach was adopted working in basic ethanol solution and then ascorbic acid was added as a reducing reagent in the second step. The obtained copper nanoparticles were characterized by UV-vis spectroscopy, XRPD and TEM analysis. UV-vis spectra show an absorption peak at about 580-590 nm, typical of the plasma resonance of copper nanoparticles and XRPD analysis reveals that the complete reduction to metallic copper was reached at the end of the second step. Average sizes in the range 7-15 nm were ascertained through TEM microscopy. These copper nanoparticles are suitable for antibacterial and antistatic applications. The bactericidal effect was investigated in relation to the diameter of inhibition zone in disk diffusion tests on calf crust leather sample and an interesting antibacterial activity was verified against both Gram positive and Gram negative bacteria (Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Candida albicans). Moreover, this treated leather showed encouraging antistatic behavior: in particular, equivalent circuital parameters were estimated via an impedance spectroscopy technique to have a first evaluation of the charge dissipation activity by volume conduction.

  13. Synthesis and thermal stability studies of a series of metastable Dion–Jacobson double-layered neodymium-niobate perovskites

    SciTech Connect

    Josepha, Elisha A.; Farooq, Sara; Mitchell, Cinnamon M.; Wiley, John B.

    2014-08-15

    The Dion–Jacobson double-layered perovskite, RbNdNb{sub 2}O{sub 7}, is used as a precursor to synthesize the series ANdNb{sub 2}O{sub 7} (A=H, Li, Na, K, NH{sub 4}, Ag), and (MCl)NdNb{sub 2}O{sub 7} (M=Mn, Fe, Cu) through ion-exchange reactions ≤400 °C. Thermal stability studies indicated that most of these compounds are metastable. A combination of X-ray powder diffraction and differential thermal analysis were used to determine various low temperature decomposition pathways; these pathways were very dependent on the interlayer species. Overall the ANdNb{sub 2}O{sub 7} series was found to be less stable than the corresponding lanthanides, ALaNb{sub 2}O{sub 7}. - Graphical abstract: A new series of topochemically-prepared metastable neodymium-containing layered perovskites are studied. - Highlights: • A series of new layered neodymium containing perovskites were synthesized by ion exchange. • Products were studied by variable temperature X-ray diffraction and thermal analysis. • Most of the series are metastable showing exothermic transitions on decomposition. • The Nd compounds are less stable due to the smaller size of the Nd relative to La.

  14. Synthesis of core/shell spinel ferrite/carbon nanoparticles with enhanced cycling stability for lithium ion battery anodes.

    PubMed

    Jin, Yun-Ho; Seo, Seung-Deok; Shim, Hyun-Woo; Park, Kyung-Soo; Kim, Dong-Wan

    2012-03-30

    Monodispersed core/shell spinel ferrite/carbon nanoparticles are formed by thermolysis of metal (Fe3+, Co2+) oleates followed by carbon coating. The phase and morphology of nanoparticles are characterized by x-ray diffraction and transmission electron microscopy. Pure Fe3O4 and CoFe2O4 nanoparticles are initially prepared through thermal decomposition of metal–oleate precursors at 310 degrees C and they are found to exhibit poor electrochemical performance because of the easy aggregation of nanoparticles and the resulting increase in the interparticle contact resistance. In contrast, uniform carbon coating of Fe3O4 and CoFe2O4 nanoparticles by low-temperature (180 degrees C) decomposition of malic acid allowed each nanoparticle to be electrically wired to a current collector through a conducting percolative path. Core/shell Fe3O4/C and CoFe2O4/C nanocomposite electrodes show a high specific capacity that can exceed 700 mAh g(-1) after 200 cycles, along with enhanced cycling stability.

  15. Green synthesis of highly stabilized nanocrystalline silver particles by a non-pathogenic and agriculturally important fungus T. asperellum

    NASA Astrophysics Data System (ADS)

    Mukherjee, P.; Roy, M.; Mandal, B. P.; Dey, G. K.; Mukherjee, P. K.; Ghatak, J.; Tyagi, A. K.; Kale, S. P.

    2008-02-01

    A controlled and up-scalable biosynthetic route to nanocrystalline silver particles with well-defined morphology using cell-free aqueous filtrate of a non-pathogenic and commercially viable biocontrol agent Trichoderma asperellum is being reported for the first time. A transparent solution of the cell-free filtrate of Trichoderma asperellum containing 1 mM AgNO3 turns progressively dark brown within 5 d of incubation at 25 °C. The kinetics of the reaction was studied using UV-vis spectroscopy. An intense surface plasmon resonance band at ~410 nm in the UV-vis spectrum clearly reveals the formation of silver nanoparticles. The size of the silver particles using TEM and XRD studies is found to be in the range 13-18 nm. These nanoparticles are found to be highly stable and even after prolonged storage for over 6 months they do not show significant aggregation. A plausible mechanism behind the formation of silver nanoparticles and their stabilization via capping has been investigated using FTIR and surface-enhanced resonance Raman spectroscopy.

  16. Synthesis, molecular structure, spectroscopic properties and stability of (Z)-N-methyl-C-2,4,6-trimethylphenylnitrone

    NASA Astrophysics Data System (ADS)

    Lasri, Jamal; Ismail, Ali I.; Haukka, Matti; Soliman, Saied M.

    2015-02-01

    New N-methyl-C-2,4,6-trimethylphenylnitrone 1 has been synthesized starting from N-methylhydroxylamine and mesitaldehyde. The product was fully characterized using different spectroscopic techniques; FTIR, NMR, UV-Vis, high resolution mass spectrometry and X-ray diffraction. The relative stability and percent of population of its two possible isomers (E and Z) were calculated using the B3LYP/6-311++G(d,p) method in gas phase and in solution. In agreement with the X-ray results, it was found that Z-isomer is the most stable one in both gas phase and solution. The molecular geometry, vibrational frequencies, gauge-including atomic orbital (GIAO), and chemical shift values were also calculated using the same level of theory. The TD-DFT results of the studied nitrone predicted a π-π∗ transition band at 285.1 nm (fosc = 0.3543) in the gas phase. The rest of the spectral bands undergo either hyperchromic or hypsochromic shifts in the presence of solvent. Polarizability and HOMO-LUMO gap values were used to predict the nonlinear optical properties (NLO) of the studied compound. NBO analysis has been used to determine the most accurate Lewis structure of the studied molecule.

  17. Synthesis and evaluation of oxidation-responsive alginate-deferoxamine conjugates with increased stability and low toxicity.

    PubMed

    Tian, Meng; Chen, Xi; Gu, Zhipeng; Li, Hao; Ma, Lu; Qi, Xin; Tan, Hong; You, Chao

    2016-06-25

    Deferoxamine is commonly used for iron-overload related diseases, its drawbacks such as instability and toxicity, however, significantly limited its utility in clinic. To address these issues, oxidation-responsive alginate-deferoxamine (Alg-DFO) conjugates were synthesized and their structure was characterized. The metabolism studies shown the conjugation of alginate significantly increased the stability of the DFO, with half-life more than 10 times longer than that of the free DFO. Moreover, the conjugates could not only quickly respond to oxidative stimuli and degradation, suggesting their potential to be cleared from the body by responding to iron-overload associated oxidative environment to avoid its accumulation and safety concern, but also protect iron binding capacity of the attached DFO from oxidation. The degradation mechanism for oxidative-response was proposed. In addition, the conjugates shown lower cytotoxicity compared to the free DFO. Taken together, the Alg-DFO conjugates synthesized in this work has promise for treating iron-overload related conditions. PMID:27083844

  18. Synthesis of PtCu nanowires in nonaqueous solvent with enhanced activity and stability for oxygen reduction reaction

    NASA Astrophysics Data System (ADS)

    Chen, Bing; Cheng, Daojian; Zhu, Jiqin

    2014-12-01

    Pt-based core-shell electrocatalysts with one-dimensional (1D) nanostructure show a great opportunity to improve the catalytic activity and durability of pure Pt catalyst for oxygen reduction reaction (ORR). Here, we synthesize Cu@CuPt core@shell nanowires (NWs) with 1D nanostructure by using Cu NWs as templates in organic solvent medium. The ORR mass activity and specific activity of PtCu NWs are 0.216 A mgpt-1 and 0.404 mA cm-2 at 0.9 V, respectively, which are 3.1 and 3.7 times larger than that of the commercial Pt/C catalyst (0.07 A mgpt-1 and 0.110 mA cm-2, respectively). Theoretical studies suggest that the electronic effect of the Cu substrate on the Pt monolayer could be the main reason for the higher activity of PtCu NWs than that of the commercial Pt/C catalyst. In addition, the PtCu NWs show much better durability than the commercial Pt/C catalyst after stability test. It is expected that the as-synthesized PtCu NWs in organic solvent medium could be excellent candidates as high performance catalysts for ORR.

  19. Synthesis, molecular structure, spectroscopic properties and stability of (Z)-N-methyl-C-2,4,6-trimethylphenylnitrone.

    PubMed

    Lasri, Jamal; Ismail, Ali I; Haukka, Matti; Soliman, Saied M

    2015-02-01

    New N-methyl-C-2,4,6-trimethylphenylnitrone 1 has been synthesized starting from N-methylhydroxylamine and mesitaldehyde. The product was fully characterized using different spectroscopic techniques; FTIR, NMR, UV-Vis, high resolution mass spectrometry and X-ray diffraction. The relative stability and percent of population of its two possible isomers (E and Z) were calculated using the B3LYP/6-311++G(d,p) method in gas phase and in solution. In agreement with the X-ray results, it was found that Z-isomer is the most stable one in both gas phase and solution. The molecular geometry, vibrational frequencies, gauge-including atomic orbital (GIAO), and chemical shift values were also calculated using the same level of theory. The TD-DFT results of the studied nitrone predicted a π-π(∗) transition band at 285.1nm (fosc=0.3543) in the gas phase. The rest of the spectral bands undergo either hyperchromic or hypsochromic shifts in the presence of solvent. Polarizability and HOMO-LUMO gap values were used to predict the nonlinear optical properties (NLO) of the studied compound. NBO analysis has been used to determine the most accurate Lewis structure of the studied molecule.

  20. 49 CFR 38.33 - Fare box.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Fare box. 38.33 Section 38.33 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY SPECIFICATIONS FOR TRANSPORTATION VEHICLES Buses, Vans and Systems § 38.33 Fare box. Where provided, the...

  1. 36 CFR 1192.33 - Fare box.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Fare box. 1192.33 Section 1192.33 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD... Systems § 1192.33 Fare box. Where provided, the farebox shall be located as far forward as practicable...

  2. 49 CFR 38.33 - Fare box.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Fare box. 38.33 Section 38.33 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY SPECIFICATIONS FOR TRANSPORTATION VEHICLES Buses, Vans and Systems § 38.33 Fare box. Where provided, the...

  3. 49 CFR 38.33 - Fare box.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Fare box. 38.33 Section 38.33 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY SPECIFICATIONS FOR TRANSPORTATION VEHICLES Buses, Vans and Systems § 38.33 Fare box. Where provided, the...

  4. 49 CFR 38.33 - Fare box.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Fare box. 38.33 Section 38.33 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY SPECIFICATIONS FOR TRANSPORTATION VEHICLES Buses, Vans and Systems § 38.33 Fare box. Where provided, the...

  5. BLS: Box-fitting Least Squares

    NASA Astrophysics Data System (ADS)

    Kovács, G.; Zucker, S.; Mazeh, T.

    2016-07-01

    BLS (Box-fitting Least Squares) is a box-fitting algorithm that analyzes stellar photometric time series to search for periodic transits of extrasolar planets. It searches for signals characterized by a periodic alternation between two discrete levels, with much less time spent at the lower level.

  6. Cereal Box Design: An Interdisciplinary Graphics Activity

    ERIC Educational Resources Information Center

    Fitzgerald, Mike; Tsosie, Teri

    2004-01-01

    This article describes cereal box design, an interdisciplinary graphics activity. The cereal box design activity is intriguing both for its simplicity and the resourcefulness that it can generate in young people. It lends itself to a variety of curriculums. It covers both consumerism and Design for the Environment (DfE) concepts broadly and in…

  7. 49 CFR 38.33 - Fare box.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Fare box. 38.33 Section 38.33 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY SPECIFICATIONS FOR TRANSPORTATION VEHICLES Buses, Vans and Systems § 38.33 Fare box. Where provided, the...

  8. Box Plots in the Australian Curriculum

    ERIC Educational Resources Information Center

    Watson, Jane M.

    2012-01-01

    This article compares the definition of "box plot" as used in the "Australian Curriculum: Mathematics" with other definitions used in the education community; describes the difficulties students experience when dealing with box plots; and discusses the elaboration that is necessary to enable teachers to develop the knowledge necessary to use them…

  9. Cosmetic Foot Surgery: Fashion's Pandora's Box

    MedlinePlus

    ... Fashion’s Pandora’s Box? A A A | Print | Share Cosmetic Foot Surgery: Fashion’s Pandora’s Box? Foot and ankle ... extreme and imprudent as it may sound, the cosmetic surgery craze isn't just for faces anymore- ...

  10. 46 CFR 111.81-3 - Cables entering boxes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Cables entering boxes. 111.81-3 Section 111.81-3...-GENERAL REQUIREMENTS Outlet Boxes and Junction Boxes § 111.81-3 Cables entering boxes. Each cable entering a box or fitting must be protected from abrasion and must meet the following: (a) Each...

  11. 46 CFR 111.81-3 - Cables entering boxes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Cables entering boxes. 111.81-3 Section 111.81-3...-GENERAL REQUIREMENTS Outlet Boxes and Junction Boxes § 111.81-3 Cables entering boxes. Each cable entering a box or fitting must be protected from abrasion and must meet the following: (a) Each...

  12. 46 CFR 111.81-3 - Cables entering boxes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Cables entering boxes. 111.81-3 Section 111.81-3...-GENERAL REQUIREMENTS Outlet Boxes and Junction Boxes § 111.81-3 Cables entering boxes. Each cable entering a box or fitting must be protected from abrasion and must meet the following: (a) Each...

  13. 46 CFR 111.81-3 - Cables entering boxes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Cables entering boxes. 111.81-3 Section 111.81-3...-GENERAL REQUIREMENTS Outlet Boxes and Junction Boxes § 111.81-3 Cables entering boxes. Each cable entering a box or fitting must be protected from abrasion and must meet the following: (a) Each...

  14. 46 CFR 111.81-3 - Cables entering boxes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Cables entering boxes. 111.81-3 Section 111.81-3...-GENERAL REQUIREMENTS Outlet Boxes and Junction Boxes § 111.81-3 Cables entering boxes. Each cable entering... through which a conductor enters must be closed. (b) Cable armor must be secured to the box or fitting....

  15. Streptococcus pneumoniae Genome-wide Identification and Characterization of BOX Element-binding Domains.

    PubMed

    Zhang, Qiao; Wang, Changzheng; Wan, Min; Wu, Yin; Ma, Qianli

    2015-11-01

    The BOX elements are short repetitive DNA sequences that distribute randomly in intergenic regions of the Streptococcus pneumoniae genome. The function and origin of such elements are still unknown, but they were found to modulate expression of neighboring genes. Evidences suggested that the modulation's mechanism can be fulfilled by sequence-specific interaction of BOX elements with transcription factor family proteins. However, the type and function of these BOX-binding proteins still remain largely unexplored to date. In the current study we described a synthetic protocol to investigate the recognition and interaction between a highly conserved site of BOX elements and the DNA-binding domains of a variety of putative transcription factors in the pneumococcal genome. With the protocol we were able to predict those high-affinity domain binders of the conserved BOX DNA site (BOX DNA) in a high-throughput manner, and analyzed sequence-specific interaction in the domainDNA recognition at molecular level. Consequently, a number of putative transcription factor domains with both high affinity and specificity for the BOX DNA were identified, from which the helix-turn-helix (HTH) motif of a small heat shock factor was selected as a case study and tested for its binding capability toward the double-stranded BOX DNA using fluorescence anisotropy analysis. As might be expected, a relatively high affinity was detected for the interaction of HTH motif with BOX DNA with dissociation constant at nanomolar level. Molecular dynamics simulation, atomic structure examination and binding energy analysis revealed a complicated network of intensive nonbonded interactions across the complex interface, which confers both stability and specificity for the complex architecture. PMID:27491035

  16. Towards long lasting zirconia-based composites for dental implants. Part I: innovative synthesis, microstructural characterization and in vitro stability.

    PubMed

    Palmero, Paola; Fornabaio, Marta; Montanaro, Laura; Reveron, Helen; Esnouf, Claude; Chevalier, Jérôme

    2015-05-01

    In order to fulfill the clinical requirements for strong, tough and stable ceramics used in dental applications, we designed and developed innovative zirconia-based composites, in which equiaxial α-Al2O3 and elongated SrAl12O19 phases are dispersed in a ceria-stabilized zirconia matrix. The composite powders were prepared by an innovative surface coating route, in which commercial zirconia powders were coated by inorganic precursors of the second phases, which crystallize on the zirconia particles surface under proper thermal treatment. Samples containing four different ceria contents (in the range 10.0-11.5 mol%) were prepared by carefully tailoring the amount of the cerium precursor during the elaboration process. Slip cast green bodies were sintered at 1450 °C for 1 h, leading to fully dense materials. Characterization of composites by SEM and TEM analyses showed highly homogeneous microstructures with an even distribution of both equiaxial and elongated-shape grains inside a very fine zirconia matrix. Ce content plays a major role on aging kinetics, and should be carefully controlled: sample with 10 mol% of ceria were transformable, whereas above 10.5 mol% there is negligible or no transformation during autoclave treatment. Thus, in this paper we show the potential of the innovative surface coating route, which allows a perfect tailoring of the microstructural, morphological and compositional features of the composites; moreover, its processing costs and environmental impacts are limited, which is beneficial for further scale-up and real use in the biomedical field.

  17. North American box turtles: A natural history

    USGS Publications Warehouse

    Dodd, C. Kenneth

    2002-01-01

    Once a familiar backyard visitor in many parts of the United States and Mexico, the box turtle is losing the battle against extinction. In North American Box Turtles, C. Kenneth Dodd, Jr., has written the first book-length natural history of the twelve species and subspecies of this endangered animal. This volume includes comprehensive information on the species’ evolution, behavior, courtship and reproduction, habitat use, diet, population structure, systematics, and disease. Special features include color photos of all species, subspecies, and their habitats; a simple identification guide to both living and fossil species; and a summary of information on fossil Terrapene and Native uses of box turtles. End-of-chapter sections highlight future research directions, including the need for long-term monitoring and observation of box turtles within their natural habitat and conservation applications. A glossary and a bibliography of literature on box turtles accompany the text.

  18. Minimum airflow reset of single-duct VAV terminal boxes

    NASA Astrophysics Data System (ADS)

    Cho, Young-Hum

    Single duct Variable Air Volume (VAV) systems are currently the most widely used type of HVAC system in the United States. When installing such a system, it is critical to determine the minimum airflow set point of the terminal box, as an optimally selected set point will improve the level of thermal comfort and indoor air quality (IAQ) while at the same time lower overall energy costs. In principle, this minimum rate should be calculated according to the minimum ventilation requirement based on ASHRAE standard 62.1 and maximum heating load of the zone. Several factors must be carefully considered when calculating this minimum rate. Terminal boxes with conventional control sequences may result in occupant discomfort and energy waste. If the minimum rate of airflow is set too high, the AHUs will consume excess fan power, and the terminal boxes may cause significant simultaneous room heating and cooling. At the same time, a rate that is too low will result in poor air circulation and indoor air quality in the air-conditioned space. Currently, many scholars are investigating how to change the algorithm of the advanced VAV terminal box controller without retrofitting. Some of these controllers have been found to effectively improve thermal comfort, indoor air quality, and energy efficiency. However, minimum airflow set points have not yet been identified, nor has controller performance been verified in confirmed studies. In this study, control algorithms were developed that automatically identify and reset terminal box minimum airflow set points, thereby improving indoor air quality and thermal comfort levels, and reducing the overall rate of energy consumption. A theoretical analysis of the optimal minimum airflow and discharge air temperature was performed to identify the potential energy benefits of resetting the terminal box minimum airflow set points. Applicable control algorithms for calculating the ideal values for the minimum airflow reset were developed and

  19. Interactome Analysis of the Human Respiratory Syncytial Virus RNA Polymerase Complex Identifies Protein Chaperones as Important Cofactors That Promote L-Protein Stability and RNA Synthesis

    PubMed Central

    Munday, Diane C.; Wu, Weining; Smith, Nikki; Fix, Jenna; Noton, Sarah Louise; Galloux, Marie; Touzelet, Olivier; Armstrong, Stuart D.; Dawson, Jenna M.; Aljabr, Waleed; Easton, Andrew J.; Rameix-Welti, Marie-Anne; de Oliveira, Andressa Peres; Simabuco, Fernando M.; Ventura, Armando M.; Hughes, David J.; Barr, John N.; Fearns, Rachel; Digard, Paul

    2014-01-01

    ABSTRACT The human respiratory syncytial virus (HRSV) core viral RNA polymerase comprises the large polymerase protein (L) and its cofactor, the phosphoprotein (P), which associate with the viral ribonucleoprotein complex to replicate the genome and, together with the M2-1 protein, transcribe viral mRNAs. While cellular proteins have long been proposed to be involved in the synthesis of HRSV RNA by associating with the polymerase complex, their characterization has been hindered by the difficulty of purifying the viral polymerase from mammalian cell culture. In this study, enhanced green fluorescent protein (EGFP)-tagged L- and P-protein expression was coupled with high-affinity anti-GFP antibody-based immunoprecipitation and quantitative proteomics to identify cellular proteins that interacted with either the L- or the P-proteins when expressed as part of a biologically active viral RNP. Several core groups of cellular proteins were identified that interacted with each viral protein including, in both cases, protein chaperones. Ablation of chaperone activity by using small-molecule inhibitors confirmed previously reported studies which suggested that this class of proteins acted as positive viral factors. Inhibition of HSP90 chaperone function in the current study showed that HSP90 is critical for L-protein function and stability, whether in the presence or absence of the P-protein. Inhibition studies suggested that HSP70 also disrupts virus biology and might help the polymerase remodel the nucleocapsid to allow RNA synthesis to occur efficiently. This indicated a proviral role for protein chaperones in HRSV replication and demonstrates that the function of cellular proteins can be targeted as potential therapeutics to disrupt virus replication. IMPORTANCE Human respiratory syncytial virus (HRSV) represents a major health care and economic burden, being the main cause of severe respiratory infections in infants worldwide. No vaccine or effective therapy is

  20. 6. VIEW OF SPILLWAY TIMBERS AND WATER CONTROL BOX, SHOWING ...

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

    6. VIEW OF SPILLWAY TIMBERS AND WATER CONTROL BOX, SHOWING WATER CONTROL BOX WITH LOWERED LAKE LEVEL - Three Bears Lake & Dams, Water Control Box, North of Marias Pass, East Glacier Park, Glacier County, MT

  1. Bis-N-heterocyclic carbene (NHC) stabilized η6-arene iron(0) complexes: synthesis, structure, reactivity, and catalytic activity.

    PubMed

    Blom, Burgert; Tan, Gengwen; Enthaler, Stephan; Inoue, Shigeyoshi; Epping, Jan Dirk; Driess, Matthias

    2013-12-01

    Reaction of FeCl2 with the chelating bis-N-heterocyclic carbene (NHC) bis-(N-Dipp-imidazole-2-ylidene)methylene (abbreviated {((Dipp)C:)2CH2}) (Dipp = 2,6-di-isopropylphenyl) affords the complex [FeCl2{((Dipp)C:)2CH2}] (1) in high yield. Reduction of complex 1 with excess KC8 with a 10-fold molar excess of PMe3 affords the Fe(II) complex [FeH{((Dipp)C:)2CH2}(PMe3)(η(2)-PMe2CH2)] (2) as a mixture of three stereoisomers. Complex 2, the first example of any iron(II) complex bearing mutually an NHC and PMe3 ligand, is likely obtained from the in situ, reductively generated 16 VE Fe(0) complex, [Fe{((Dipp)C:)2CH2}(PMe3)2] (2'), following intramolecular C-H activation of one of the phosphorus-bound CH3 groups. Complex 2 is unstable in aromatic solvents and forms, via a novel synthetic transformation involving intramolecular reductive elimination and concomitant PMe3 elimination, the Fe (0) arene complex [Fe{((Dipp)C:)2CH2}(η(6)-C6D6)] (4-d6) in C6D6. Complex 4-d6 represents the first example of an NHC stabilized iron (0) arene complex. The transformation from 2 to 4-d6 can be accelerated at higher temperature and at 60 °C forms immediately. Alternatively, the reduction of 1 in the presence of toluene or benzene affords the complexes [Fe{((Dipp)C:)2CH2}(η(6)-C7H8)] (3) and [Fe{((Dipp)C:)2CH2}(η(6)-C6H6)] (4), selectively and in good yields. DFT calculations characterizing the bonding situation in 3 and 4 reveal similar energies of the HOMO and LUMO orbitals, with the LUMO orbital of both complexes located on the Dipp rings of the bis-NHC. The HOMO orbital reflects a π-back-bonding interaction between the Fe(0) center and the chelating NHC ligand, while the HOMO-1 is associated with the arene interaction with the Fe(0) site. The calculations do not suggest any noninnocence of the coordinated arene in either complex. Moreover, the (57)Fe Mössbauer spectrum of 4 at 80K exhibits parameters (δ = 0.43 mm·s(-1); ΔEQ = 1.37 mm·s(-1)) which are consistent with a five

  2. Hydro-Balanced Stuffing Box field test

    SciTech Connect

    Giangiacomo, L.A.

    1999-05-28

    The Hydro-Balanced Stuffing Box is a seal assembly for polished rod pumping installations commonly used in oil and gas pumping well installations to contain produced well fluids. The improved stuffing box was developed and patented by Harold H. Palmour of The Palmour Group of Livingston, TX. The stuffing box is designed to reduce the incidence of seal leakage and to utilize an environmentally safe fluid, so that if there is any leakage, environmental damage is reduced or eliminated. The unit was tested on two wells at the Rocky Mountain Oilfield Testing Center. During the test period, the performance of the stuffing box was measured by monitoring the pressure on the tubing and the inner chamber with a Barton Two-pen recorder. The amount of safe fluid consumed, fluid leakage at the top of the stuffing box, pressure supplied from the nitrogen bottle, ambient temperature, and polish rod temperature was recorded. The stuffing box is capable of providing a better seal between well fluids an d the environment than conventional stuffing boxes. It allows the polished rod to operate cooler and with lubrication, extending the life of the packing elements, and reducing the amount of attention required to prevent leakage.

  3. NSs Virulence Factor of Rift Valley Fever Virus Engages the F-Box Proteins FBXW11 and β-TRCP1 To Degrade the Antiviral Protein Kinase PKR

    PubMed Central

    Kainulainen, Markus; Lau, Simone; Samuel, Charles E.; Hornung, Veit

    2016-01-01

    ABSTRACT Rift Valley fever virus (RVFV, family Bunyaviridae, genus Phlebovirus) is a relevant pathogen of both humans and livestock in Africa. The nonstructural protein NSs is a major virulence factor known to suppress the type I interferon (IFN) response by inhibiting host cell transcription and by proteasomal degradation of a major antiviral IFN effector, the translation-inhibiting protein kinase PKR. Here, we identified components of the modular SCF (Skp1, Cul1, F-box protein)-type E3 ubiquitin ligases as mediators of PKR destruction by NSs. Small interfering RNAs (siRNAs) against the conserved SCF subunit Skp1 protected PKR from NSs-mediated degradation. Consequently, RVFV replication was severely reduced in Skp1-depleted cells when PKR was present. SCF complexes have a variable F-box protein subunit that determines substrate specificity for ubiquitination. We performed an siRNA screen for all (about 70) human F-box proteins and found FBXW11 to be involved in PKR degradation. The partial stabilization of PKR by FBXW11 depletion upregulated PKR autophosphorylation and phosphorylation of the PKR substrate eIF2α and caused a shutoff of host cell protein synthesis in RVFV-infected cells. To maximally protect PKR from the action of NSs, knockdown of structurally and functionally related FBXW1 (also known as β-TRCP1), in addition to FBXW11 deletion, was necessary. Consequently, NSs was found to interact with both FBXW11 and β-TRCP1. Thus, NSs eliminates the antiviral kinase PKR by recruitment of SCF-type E3 ubiquitin ligases containing FBXW11 and β-TRCP1 as substrate recognition subunits. This antagonism of PKR by NSs is essential for efficient RVFV replication in mammalian cells. IMPORTANCE Rift Valley fever virus is a pathogen of humans and animals that has the potential to spread from Africa and the Arabian Peninsula to other regions. A major virulence mechanism is the proteasomal degradation of the antiviral kinase PKR by the viral protein NSs. Here, we

  4. Eco-friendly microwave-assisted green and rapid synthesis of well-stabilized gold and core-shell silver-gold nanoparticles.

    PubMed

    El-Naggar, Mehrez E; Shaheen, Tharwat I; Fouda, Moustafa M G; Hebeish, Ali A

    2016-01-20

    Herein, we present a new approach for the synthesis of gold nanoparticles (AuNPs) individually and as bimetallic core-shell nanoparticles (AgNPs-AuNPs). The novelty of the approach is further maximized by using curdlan (CRD) biopolymer to perform the dual role of reducing and capping agents and microwave-aided technology for affecting the said nanoparticles with varying concentrations in addition to those affected by precursor concentrations. Thus, for preparation of AuNPs, curdlan was solubilized in alkali solution followed by an addition of tetrachloroauric acid (HAuCl4). The curdlan solution containing HAuCl4 was then subjected to microwave radiation for up to 10 min. The optimum conditions obtained with the synthesis of AuNPs were employed for preparation of core-shell silver-gold nanoparticles by replacing definite portion of HAuCl4 with an equivalent portion of silver nitrate (AgNO3). The portion of AgNO3 was added initially and allowed to be reduced by virtue of the dual role of curdlan under microwave radiation. The corresponding portion of HAuCl4 was then added and allowed to complete the reaction. Characterization of AuNPs and AgNPs-AuNPs core-shell were made using UV-vis spectra, TEM, FTIR, XRD, zeta potential, and AFM analysis. Accordingly, strong peaks of the colloidal particles show surface plasmon resonance (SPR) at maximum wavelength of 540 nm, proving the formation of well-stabilized gold nanoparticles. TEM investigations reveal that the major size of AuNPs formed at different Au(+3)concentration lie below 20 nm with narrow size distribution. Whilst, the SPR bands of AgNPs-AuNPs core-shell differ than those obtained from original AgNPs (420 nm) and AuNPs (540 nm). Such shifting due to SPR of Au nanoshell deposited onto AgNPs core was significantly affected by the variation of bimetallic ratios applied. TEM micrographs show variation in contrast between dark silver core and the lighter gold shell. Increasing the ratio of silver ions leads to

  5. Folding of a Cyclin Box

    PubMed Central

    Chemes, Lucía B.; Noval, María G.; Sánchez, Ignacio E.; de Prat-Gay, Gonzalo

    2013-01-01

    The retinoblastoma tumor suppressor (Rb) controls the proliferation, differentiation, and survival of cells in most eukaryotes with a role in the fate of stem cells. Its inactivation by mutation or oncogenic viruses is required for cellular transformation and eventually carcinogenesis. The high conservation of the Rb cyclin fold prompted us to investigate the link between conformational stability and ligand binding properties of the RbAB pocket domain. RbAB unfolding presents a three-state transition involving cooperative secondary and tertiary structure changes and a partially folded intermediate that can oligomerize. The first transition corresponds to unfolding of the metastable B subdomain containing the binding site for the LXCXE motif present in cellular and viral targets, and the second transition corresponds to the stable A subdomain. The low thermodynamic stability of RbAB translates into a propensity to rapidly oligomerize and aggregate at 37 °C (T50 = 28 min) that is suppressed by human papillomavirus E7 and E2F peptide ligands, suggesting that Rb is likely stabilized in vivo through binding to target proteins. We propose that marginal stability and associated oligomerization may be conserved for function as a “hub” protein, allowing the formation of multiprotein complexes, which could constitute a robust mechanism to retain its cell cycle regulatory role throughout evolution. Decreased stability and oligomerization are shared with the p53 tumor suppressor, suggesting a link between folding and function in these two essential cell regulators that are inactivated in most cancers and operate within multitarget signaling pathways. PMID:23632018

  6. HYDROGEN RETENTION IN METAL WASTE BOXES

    SciTech Connect

    MARUSICH, R.M.

    2004-11-18

    The Hanford Waste Management Project Master Documented Safety Analysis (MDSA) (HNF-14741,2003) identifies derived safety controls to prevent or mitigate the risks of a single- container deflagration during operations requiring moving, venting or opening transuranic (TRU)-waste containers. The issue is whether these safety controls are necessary for operations involving TRU-waste boxes that are being retrieved from burial at the Hanford Site. This paper investigates the potential for a deflagration hazard within these boxes and whether safety controls identified for drum deflagration hazards should be applied to operations involving these boxes.

  7. Affinity and selectivity of C2- and C5-substituted "chiral-box" PNA in solution and on microarrays.

    PubMed

    Manicardi, Alex; Calabretta, Alessandro; Bencivenni, Mariangela; Tedeschi, Tullia; Sforza, Stefano; Corradini, Roberto; Marchelli, Rosangela

    2010-01-01

    Two peptide nucleic acids (PNAs) containing three adjacent modified chiral monomers (chiral box) were synthesized. The chiral monomers contained either a C2- or a C5-modified backbone, synthesized starting from D- and L-arginine, respectively (2D- and 5L-PNA). The C2-modified chiral PNA was synthesized using a submonomeric strategy to avoid epimerization during solid-phase synthesis, whereas for the C5-derivative, the monomers were first obtained and then used in solid-phase synthesis. The melting temperature of these PNA duplexes formed with the full-match or with single-mismatch DNA were measured both by UV and by CD spectroscopy and compared with the unmodified PNA. The 5L-chiral-box-PNA showed the highest T(m) with full-match DNA, whereas the 2D-chiral-box-PNA showed the highest sequence selectivity. The PNA were spotted on microarray slides and then hybridized with Cy5-labeled full match and mismatched oligonucleotides. The results obtained showed a signal intensity in the order achiral >2D-chiral box >5L-chiral box, whereas the full-match/mismatch selectivity was higher for the 2D chiral box PNA. PMID:21038387

  8. [Prognosis of affinity change of the TATA-binding protein to TATA-boxes upon polymorphisms of the human gene promoter TATA boxes].

    PubMed

    Ponomarenko, P M; Ponomarenko, M P; Drachkova, I A; Lysova, M V; Arshinova, T V; Savinkova, L K; Kolchanov, N A

    2009-01-01

    TATA-binding protein (TBP) is a subunit of basal transcription factor TFIID that recognizes and binds to the TATA-box on TATA-containing promoters of class II genes, and starts assembling RNA polymerase II basal transcription complex. It is shown in many works that the sequence of TATA-box with its flanking regions affects the level of basal and activated transcription. TATA-box polymorphisms and human hereditary diseases associated with them show that TBP/TATA interaction may indirectly affect gene regulation in vivo. The object of this work is to determine changes in the TBP/TATA affinity upon polymorphisms in TATA-boxes of human gene promoters. We assess changes in TBP/TATA affinities in silico by using our formula of equilibrium TBP/TATA binding upon four consecutive steps: nonspecific binding <--> sliding <--> braking (stopping) <--> stabilization. Our prognoses agree with known examples of TATA-box polymorphisms and human hereditary diseases associated with them. PMID:19548537

  9. Ultrafast conformational dynamics of electron transfer in ExBox4+⊂perylene.

    PubMed

    Young, Ryan M; Dyar, Scott M; Barnes, Jonathan C; Juríček, Michal; Stoddart, J Fraser; Co, Dick T; Wasielewski, Michael R

    2013-11-27

    Multielectron acceptors are essential components for artificial photosynthetic systems that must deliver multiple electrons to catalysts for solar fuels applications. The recently developed boxlike cyclophane incorporating two extended viologen units joined end-to-end by two p-phenylene linkers-namely, ExBox(4+)-has a potential to be integrated into light-driven systems on account of its ability to complex with π-electron-rich guests such as perylene, which has been utilized to great extent in many light-harvesting applications. Photodriven electron transfer to ExBox(4+) has not previously been investigated, however, and so its properties, following photoreduction, are largely unknown. Here, we investigate the structure and energetics of the various accessible oxidation states of ExBox(4+) using a combination of spectroscopy and computation. In particular, we examine photoinitiated electron transfer from perylene bound within ExBox(4+) (ExBox(4+)⊂perylene) using visible and near-infrared femtosecond transient absorption (fsTA) spectroscopy. The structure and conformational relaxation dynamics of ExBox(3+)⊂perylene(+) are observed with femtosecond stimulated Raman spectroscopy (FSRS). From the fsTA and FSRS spectra, we observe that the central p-phenylene spacer in one of the extended viologen units on one side of the cyclophane becomes more coplanar with its neighboring pyridinium units over the first ∼5 ps after photoreduction. When the steady-state structure of chemically generated ExBox(2+) is investigated using Raman spectroscopy, it is found to have the central p-phenylene rings in both of its extended viologen units rotated to be more coplanar with their neighboring pyridinium units, further underscoring the importance of this subunit in the stabilization of the reduced states of ExBox(4+). PMID:24148089

  10. 36 CFR 1192.33 - Fare box.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY GUIDELINES FOR TRANSPORTATION VEHICLES Buses, Vans and Systems § 1192.33 Fare box. Where provided, the farebox shall be located as far forward as practicable...

  11. 36 CFR 1192.33 - Fare box.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY GUIDELINES FOR TRANSPORTATION VEHICLES Buses, Vans and Systems § 1192.33 Fare box. Where provided, the farebox shall be located as far forward as practicable...

  12. 36 CFR 1192.33 - Fare box.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY GUIDELINES FOR TRANSPORTATION VEHICLES Buses, Vans and Systems § 1192.33 Fare box. Where provided, the farebox shall be located as far forward as practicable...

  13. 36 CFR 1192.33 - Fare box.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY GUIDELINES FOR TRANSPORTATION VEHICLES Buses, Vans and Systems § 1192.33 Fare box. Where provided, the farebox shall be located as far forward as practicable...

  14. Mystery Boxes, X Rays, and Radiology.

    ERIC Educational Resources Information Center

    Thomson, Norman

    2000-01-01

    Indicates the difficulties of teaching concepts beyond light and color and creating memorable learning experiences. Recommends sequential activities using the mystery box approach to explain how scientists and doctors use photon applications. (YDS)

  15. BOX DIMENSIONS OF α-FRACTAL FUNCTIONS

    NASA Astrophysics Data System (ADS)

    Akhtar, Md. Nasim; Prasad, M. Guru Prem; Navascués, M. A.

    2016-08-01

    The box dimension of the graph of non-affine, continuous, nowhere differentiable function fα which is a fractal analogue of a continuous function f corresponding to a certain iterated function system (IFS), is investigated in the present paper. The estimates for box dimension of the graph of α-fractal function fα for equally spaced as well as arbitrary data sets are found.

  16. BOX-DEATH HOLLOW ROADLESS AREA, UTAH.

    USGS Publications Warehouse

    Weir, Gordon W.; Lane, Michael

    1984-01-01

    Geologic mapping, geochemical sampling, and a search for prospects and mineralized rock in the Box-Death Hollow Roadless Area, Utah indicate that there is little promise for the occurrence of mineral or energy resources in the area. Additional exploratory drilling by industry seems warranted if wells elsewhere in the region find oil or gas in strata as yet untested in the Box-Death Hollow Roadless Area.

  17. Glove box on vehicular instrument panel

    DOEpatents

    Atarashi, Kazuya

    1985-01-01

    A glove box for the upper surface of an automobile dashboard whereby it may be positioned close to the driver. The glove box lid is pivotally supported by arms extending down either side to swing forwardly for opening. A hook is pivotally support adjacent an arm and weighted to swing into engagement with the arm to prevent opening of the lid during abrupt deceleration. A toggle spring assists in maintaining the lid in either the open or closed position.

  18. Genetic screening with the DNA chip: a new Pandora's box?

    PubMed Central

    Henn, W

    1999-01-01

    The ethically controversial option of genetic population screening used to be restricted to a small number of rather rare diseases by methodological limitations which are now about to be overcome. With the new technology of DNA microarrays ("DNA chip"), emerging from the synthesis of microelectronics and molecular biology, methods are now at hand for the development of mass screening programmes for a wide spectrum of genetic traits. Thus, the DNA chip may be the key technology for a refined preventive medicine as well as a new dimension of eugenics. The forthcoming introduction of the DNA chip technology into medical practice urgently requires an internationally consistent framework of ethical standards and legal limitations if we do not want it to become a new Pandora's box. PMID:10226928

  19. Amateur boxing: physical and physiological attributes.

    PubMed

    Chaabène, Helmi; Tabben, Montassar; Mkaouer, Bessem; Franchini, Emerson; Negra, Yassine; Hammami, Mehrez; Amara, Samiha; Chaabène, Raja Bouguezzi; Hachana, Younés

    2015-03-01

    Boxing is one of the oldest combat sports. The aim of the current review is to critically analyze the amateur boxer's physical and physiological characteristics and to provide practical recommendations for training as well as new areas of scientific research. High-level male and female boxers show a propensity for low body fat levels. Although studies on boxer somatotypes are limited, the available information shows that elite-level male boxers are characterized by a higher proportion of mesomorphy with a well-developed muscle mass and a low body fat level. To help support the overall metabolic demands of a boxing match and to accelerate the recovery process between rounds, athletes of both sexes require a high level of cardiorespiratory fitness. International boxers show a high peak and mean anaerobic power output. Muscle strength in both the upper and lower limbs is paramount for a fighter's victory and is one of the keys to success in boxing. As boxing punches are brief actions and very dynamic, high-level boxing performance requires well-developed muscle power in both the upper and lower limbs. Albeit limited, the available studies reveal that isometric strength is linked to high-level boxing performance. Future investigations into the physical and physiological attributes of boxers are required to enrich the current data set and to help create a suitable training program. PMID:25358529

  20. HYDROGEN AND VOC RETENTION IN WASTE BOXES

    SciTech Connect

    PACE ME; MARUSICH RM

    2008-11-21

    The Hanford Waste Management Project Master Documented Safety Analysis (MDSA) (HNF-14741, 2003) identifies derived safety controls to prevent or mitigate the risks of a single-container deflagration during operations requiring moving, venting or opening transuranic (TRU)-waste containers. The issue is whether these safety controls are necessary for operations involving TRU-waste boxes that are being retrieved from burial at the Hanford Site. This paper investigates the potential for a deflagration hazard within these boxes and whether safety controls identified for drum deflagration hazards should be applied to operations involving these boxes. The study evaluates the accumulation of hydrogen and VOCs within the waste box and the transport of these gases and vapors out of the waste box. To perform the analysis, there were numerous and major assumptions made regarding the generation rate and the transport pathway dimensions and their number. Since there is little actual data with regards to these assumptions, analyses of three potential configurations were performed to obtain some indication of the bounds of the issue (the concentration of hydrogen or flammable VOCs within a waste box). A brief description of each of the three cases along with the results of the analysis is summarized.

  1. 46 CFR 78.47-10 - Manual alarm boxes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Manual alarm boxes. 78.47-10 Section 78.47-10 Shipping... and Emergency Equipment, Etc. § 78.47-10 Manual alarm boxes. (a) In all new installations, manual alarm boxes shall be clearly and permanently marked “IN CASE OF FIRE BREAK GLASS.” Existing boxes not...

  2. 48 CFR 908.7118 - Rental of post office boxes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... boxes. 908.7118 Section 908.7118 Federal Acquisition Regulations System DEPARTMENT OF ENERGY COMPETITION... post office boxes. DOE offices and authorized contractors may rent post office boxes on an annual basis... the whole period or at the beginning of each quarter in which the box is to be used....

  3. 48 CFR 908.7118 - Rental of post office boxes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... boxes. 908.7118 Section 908.7118 Federal Acquisition Regulations System DEPARTMENT OF ENERGY COMPETITION... post office boxes. DOE offices and authorized contractors may rent post office boxes on an annual basis... the whole period or at the beginning of each quarter in which the box is to be used....

  4. 49 CFR 178.514 - Standards for plywood boxes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Standards for plywood boxes. 178.514 Section 178...-bulk Performance-Oriented Packaging Standards § 178.514 Standards for plywood boxes. (a) The identification code for a plywood box is 4D. (b) Construction requirements for plywood boxes are as follows:...

  5. 46 CFR 78.47-10 - Manual alarm boxes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Manual alarm boxes. 78.47-10 Section 78.47-10 Shipping... and Emergency Equipment, Etc. § 78.47-10 Manual alarm boxes. (a) In all new installations, manual alarm boxes shall be clearly and permanently marked “IN CASE OF FIRE BREAK GLASS.” Existing boxes not...

  6. 49 CFR 178.514 - Standards for plywood boxes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Standards for plywood boxes. 178.514 Section 178...-bulk Performance-Oriented Packaging Standards § 178.514 Standards for plywood boxes. (a) The identification code for a plywood box is 4D. (b) Construction requirements for plywood boxes are as follows:...

  7. 48 CFR 908.7118 - Rental of post office boxes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... boxes. 908.7118 Section 908.7118 Federal Acquisition Regulations System DEPARTMENT OF ENERGY COMPETITION... post office boxes. DOE offices and authorized contractors may rent post office boxes on an annual basis... the whole period or at the beginning of each quarter in which the box is to be used....

  8. 46 CFR 78.47-10 - Manual alarm boxes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Manual alarm boxes. 78.47-10 Section 78.47-10 Shipping... and Emergency Equipment, Etc. § 78.47-10 Manual alarm boxes. (a) In all new installations, manual alarm boxes shall be clearly and permanently marked “IN CASE OF FIRE BREAK GLASS.” Existing boxes not...

  9. 46 CFR 78.47-10 - Manual alarm boxes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Manual alarm boxes. 78.47-10 Section 78.47-10 Shipping... and Emergency Equipment, Etc. § 78.47-10 Manual alarm boxes. (a) In all new installations, manual alarm boxes shall be clearly and permanently marked “IN CASE OF FIRE BREAK GLASS.” Existing boxes not...

  10. 48 CFR 908.7118 - Rental of post office boxes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... boxes. 908.7118 Section 908.7118 Federal Acquisition Regulations System DEPARTMENT OF ENERGY COMPETITION... post office boxes. DOE offices and authorized contractors may rent post office boxes on an annual basis... the whole period or at the beginning of each quarter in which the box is to be used....

  11. 48 CFR 908.7118 - Rental of post office boxes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... boxes. 908.7118 Section 908.7118 Federal Acquisition Regulations System DEPARTMENT OF ENERGY COMPETITION... post office boxes. DOE offices and authorized contractors may rent post office boxes on an annual basis... the whole period or at the beginning of each quarter in which the box is to be used....

  12. 49 CFR 178.514 - Standards for plywood boxes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Standards for plywood boxes. 178.514 Section 178...-bulk Performance-Oriented Packaging Standards § 178.514 Standards for plywood boxes. (a) The identification code for a plywood box is 4D. (b) Construction requirements for plywood boxes are as follows:...

  13. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  14. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  15. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  16. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  17. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  18. Rocaglates convert DEAD-box protein eIF4A into a sequence-selective translational repressor.

    PubMed

    Iwasaki, Shintaro; Floor, Stephen N; Ingolia, Nicholas T

    2016-06-23

    Rocaglamide A (RocA) typifies a class of protein synthesis inhibitors that selectively kill aneuploid tumour cells and repress translation of specific messenger RNAs. RocA targets eukaryotic initiation factor 4A (eIF4A), an ATP-dependent DEAD-box RNA helicase; its messenger RNA selectivity is proposed to reflect highly structured 5' untranslated regions that depend strongly on eIF4A-mediated unwinding. However, rocaglate treatment may not phenocopy the loss of eIF4A activity, as these drugs actually increase the affinity between eIF4A and RNA. Here we show that secondary structure in 5' untranslated regions is only a minor determinant for RocA selectivity and that RocA does not repress translation by reducing eIF4A availability. Rather, in vitro and in cells, RocA specifically clamps eIF4A onto polypurine sequences in an ATP-independent manner. This artificially clamped eIF4A blocks 43S scanning, leading to premature, upstream translation initiation and reducing protein expression from transcripts bearing the RocA-eIF4A target sequence. In elucidating the mechanism of selective translation repression by this lead anti-cancer compound, we provide an example of a drug stabilizing sequence-selective RNA-protein interactions. PMID:27309803

  19. Rocaglates convert DEAD-box protein eIF4A into a sequence-selective translational repressor.

    PubMed

    Iwasaki, Shintaro; Floor, Stephen N; Ingolia, Nicholas T

    2016-06-15

    Rocaglamide A (RocA) typifies a class of protein synthesis inhibitors that selectively kill aneuploid tumour cells and repress translation of specific messenger RNAs. RocA targets eukaryotic initiation factor 4A (eIF4A), an ATP-dependent DEAD-box RNA helicase; its messenger RNA selectivity is proposed to reflect highly structured 5' untranslated regions that depend strongly on eIF4A-mediated unwinding. However, rocaglate treatment may not phenocopy the loss of eIF4A activity, as these drugs actually increase the affinity between eIF4A and RNA. Here we show that secondary structure in 5' untranslated regions is only a minor determinant for RocA selectivity and that RocA does not repress translation by reducing eIF4A availability. Rather, in vitro and in cells, RocA specifically clamps eIF4A onto polypurine sequences in an ATP-independent manner. This artificially clamped eIF4A blocks 43S scanning, leading to premature, upstream translation initiation and reducing protein expression from transcripts bearing the RocA-eIF4A target sequence. In elucidating the mechanism of selective translation repression by this lead anti-cancer compound, we provide an example of a drug stabilizing sequence-selective RNA-protein interactions.

  20. Preliminary analysis on hybrid Box-Jenkins - GARCH modeling in forecasting gold price

    NASA Astrophysics Data System (ADS)

    Yaziz, Siti Roslindar; Azizan, Noor Azlinna; Ahmad, Maizah Hura; Zakaria, Roslinazairimah; Agrawal, Manju; Boland, John

    2015-02-01

    Gold has been regarded as a valuable precious metal and the most popular commodity as a healthy return investment. Hence, the analysis and prediction of gold price become very significant to investors. This study is a preliminary analysis on gold price and its volatility that focuses on the performance of hybrid Box-Jenkins models together with GARCH in analyzing and forecasting gold price. The Box-Cox formula is used as the data transformation method due to its potential best practice in normalizing data, stabilizing variance and reduces heteroscedasticity using 41-year daily gold price data series starting 2nd January 1973. Our study indicates that the proposed hybrid model ARIMA-GARCH with t-innovation can be a new potential approach in forecasting gold price. This finding proves the strength of GARCH in handling volatility in the gold price as well as overcomes the non-linear limitation in the Box-Jenkins modeling.

  1. 46 CFR 111.81-1 - Outlet boxes and junction boxes; general.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... standards, all of which are incorporated by reference (see 46 CFR 110.10-1): Article 314 of NFPA NEC 2002... fixture, wiring device, or similar item, including each separately installed connection and junction box... junction box must have a cover unless a fixture canopy, switch cover, receptacle cover, or other cover...

  2. 46 CFR 111.81-1 - Outlet boxes and junction boxes; general.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... standards, all of which are incorporated by reference (see 46 CFR 110.10-1): Article 314 of NFPA NEC 2002... fixture, wiring device, or similar item, including each separately installed connection and junction box... junction box must have a cover unless a fixture canopy, switch cover, receptacle cover, or other cover...

  3. 46 CFR 111.81-1 - Outlet boxes and junction boxes; general.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... standards, all of which are incorporated by reference (see 46 CFR 110.10-1): Article 314 of NFPA NEC 2002... fixture, wiring device, or similar item, including each separately installed connection and junction box... junction box must have a cover unless a fixture canopy, switch cover, receptacle cover, or other cover...

  4. Slat Heater Boxes for Thermal Vacuum Testing

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene

    2003-01-01

    Slat heater boxes have been invented for controlling the sink temperatures of objects under test in a thermal vacuum chamber, the walls of which are cooled to the temperature of liquid nitrogen. A slat heater box (see Figure 1) includes a framework of struts that support electrically heated slats that are coated with a high-emissivity optically gray paint. The slats can be grouped together into heater zones for the purpose of maintaining an even temperature within each side. The sink temperature of an object under test is defined as the steady-state temperature of the object in the vacuum/ radiative environment during the absence of any internal heat source or sink. The slat heater box makes it possible to closely control the radiation environment to obtain a desired sink temperature. The slat heater box is placed inside the cold thermal vacuum chamber, and the object under test is placed inside (but not in contact with) the slat heater box. The slat heaters occupy about a third of the field of view from any point on the surface of the object under test, the remainder of the field of view being occupied by the cold chamber wall. Thus, the radiation environment is established by the combined effects of the slat heater box and the cold chamber wall. Given (1) the temperature of the chamber wall, (2) the fractions of the field of view occupied by the chamber wall and the slat heater box, and (3) the emissivities of the slats, chamber wall, and the surface of object under test, the slat temperature required to maintain a desired sink temperature can be calculated by solving the equations of gray-body radiation for the steady-state adiabatic case (equal absorption and emission by the object under test). Slat heater boxes offer an important advantage over the infrared lamps that have been previously used to obtain desired sink temperatures: In comparison with an infrared lamp, a slat heater box provides a greater degree of sink temperature uniformity for a test

  5. BMI Sandwich Wing Box Analysis and Test

    NASA Technical Reports Server (NTRS)

    Palm, Tod; Mahler, Mary; Shah, Chandu; Rouse, Marshall; Bush, Harold; Wu, Chauncey; Small, William J.

    2000-01-01

    A composite sandwich single bay wing box test article was developed by Northrop Grumman and tested recently at NASA Langley Research Center. The objectives for the wing box development effort were to provide a demonstration article for manufacturing scale up of structural concepts related to a high speed transport wing, and to validate the structural performance of the design. The box concept consisted of highly loaded composite sandwich wing skins, with moderately loaded composite sandwich spars. The dimensions of the box were chosen to represent a single bay of the main wing box, with a spar spacing of 30 inches, height of 20 inches constant depth, and length of 64 inches. The bismaleimide facesheet laminates and titanium honeycomb core chosen for this task are high temperature materials able to sustain a 300F service temperature. The completed test article is shown in Figure 1. The tests at NASA Langley demonstrated the structures ability to sustain axial tension and compression loads in excess of 20,000 lb/in, and to maintain integrity in the thermal environment. Test procedures, analysis failure predictions, and test results are presented.

  6. Chemical stabilization and high pressure synthesis of Ba-free Hg-based superconductors, (Hg,M)Sr2Ca(n-1)Cu(n)O(y)(n=1 to approximately 3)

    NASA Technical Reports Server (NTRS)

    Kishio, K.; Shimoyama, J.; Hahakura, S.; Kitazawa, K.; Yamaura, K.; Hiroi, Z.; Takano, M.

    1995-01-01

    A homologous series of new Hg-based HTSC compounds, (Hg,M)Sr2Ca(n - 1)Cu(n)P(y) with n = 1 to 3, have been synthesized. The stabilization of the pure phases have been accomplished by chemical doping of third elements such as M = Cr, Mo and Re. While the Hgl2O1(n = 1) phase was readily obtained in this way, it was necessary to simultaneously dope Y into the Ca site to stabilize the Hg1212(n = 2) phase. On the other hand, single-phase Y-free Hg1212(n = 2) and Hg1223 (n = 3) samples were synthesized only under a high pressure of 6 GPa. In sharp contrast to the Ba containing compounds, all the samples prepared in the present study have been quite stable during the synthesis and no deterioration in air has been observed after the preparation.

  7. Chemical stabilization and high pressure synthesis of Ba-free Hg-based superconductors, (Hg,M)Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub y}(N=1{approximately}3)

    SciTech Connect

    Kishio, K. |; Shimoyama, J.; Hahakura, S.

    1994-12-31

    A homologous series of new Hg-based HTSC compounds, (Hg,M)Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub y} with n=1 to 3, have been synthesized. The stabilization of the pure phases have been accomplished by chemical doping of third elements such as M=Cr, Mo and Re. While the Hg1201(n=1) phase was readily obtained in this way, it was necessary to simultaneously dope Y into the Ca site to stabilize the Hg1212(n=2) phase. On the other hand, single-phase Y-free Hg1212(n=2) and Hg1223(n=3) samples were synthesized only under a high pressure of 6 GPa. In sharp contrast to the Ba-containing compounds, all the samples prepared in the present study have been quite stable during the synthesis and no deterioration in air has been observed after the preparation.

  8. A Network of HMG-box Transcription Factors Regulates Sexual Cycle in the Fungus Podospora anserina

    PubMed Central

    Ait Benkhali, Jinane; Coppin, Evelyne; Brun, Sylvain; Peraza-Reyes, Leonardo; Martin, Tom; Dixelius, Christina; Lazar, Noureddine; van Tilbeurgh, Herman; Debuchy, Robert

    2013-01-01

    High-mobility group (HMG) B proteins are eukaryotic DNA-binding proteins characterized by the HMG-box functional motif. These transcription factors play a pivotal role in global genomic functions and in the control of genes involved in specific developmental or metabolic pathways. The filamentous ascomycete Podospora anserina contains 12 HMG-box genes. Of these, four have been previously characterized; three are mating-type genes that control fertilization and development of the fruit-body, whereas the last one encodes a factor involved in mitochondrial DNA stability. Systematic deletion analysis of the eight remaining uncharacterized HMG-box genes indicated that none were essential for viability, but that seven were involved in the sexual cycle. Two HMG-box genes display striking features. PaHMG5, an ortholog of SpSte11 from Schizosaccharomyces pombe, is a pivotal activator of mating-type genes in P. anserina, whereas PaHMG9 is a repressor of several phenomena specific to the stationary phase, most notably hyphal anastomoses. Transcriptional analyses of HMG-box genes in HMG-box deletion strains indicated that PaHMG5 is at the hub of a network of several HMG-box factors that regulate mating-type genes and mating-type target genes. Genetic analyses revealed that this network also controls fertility genes that are not regulated by mating-type transcription factors. This study points to the critical role of HMG-box members in sexual reproduction in fungi, as 11 out of 12 members were involved in the sexual cycle in P. anserina. PaHMG5 and SpSte11 are conserved transcriptional regulators of mating-type genes, although P. anserina and S. pombe diverged 550 million years ago. Two HMG-box genes, SOX9 and its upstream regulator SRY, also play an important role in sex determination in mammals. The P. anserina and S. pombe mating-type genes and their upstream regulatory factor form a module of HMG-box genes analogous to the SRY/SOX9 module, revealing a commonality of sex

  9. Implementation of the Shearing Box Approximation in Athena

    NASA Astrophysics Data System (ADS)

    Stone, James M.; Gardiner, Thomas A.

    2010-07-01

    We describe the implementation of the shearing box approximation for the study of the dynamics of accretion disks in the Athena magnetohydrodynamic (MHD) code. Second-order Crank-Nicholson time differencing is used for the Coriolis and tidal gravity source terms that appear in the momentum equation for accuracy and stability. We show that this approach conserves energy for epicyclic oscillations in hydrodynamic flows to round-off error. In the energy equation, the tidal gravity source terms are differenced as the gradient of an effective potential in a way that guarantees that total energy (including the gravitational potential energy) is also conserved to round-off error. We introduce an orbital advection algorithm for MHD based on constrained transport to preserve the divergence-free constraint on the magnetic field. This algorithm removes the orbital velocity from the time step constraint, and makes the truncation error more uniform in radial position. Modifications to the shearing box boundary conditions applied at the radial boundaries are necessary to conserve the total vertical magnetic flux. In principle, similar corrections are also required to conserve mass, momentum, and energy; however in practice we find that the orbital advection method conserves these quantities to better than 0.03% over hundreds of orbits. The algorithms have been applied to studies of the nonlinear regime of the MRI in very wide (up to 32 scale heights) horizontal domains.

  10. Shapes of a liquid droplet in a periodic box

    NASA Astrophysics Data System (ADS)

    Prestipino, Santi; Caccamo, Carlo; Costa, Dino; Malescio, Gianpietro; Munaò, Gianmarco

    2015-08-01

    Within the coexistence region between liquid and vapor the equilibrium pressure of a simulated fluid exhibits characteristic jumps and plateaus when plotted as a function of density at constant temperature. These features exclusively pertain to a finite-size sample in a periodic box, as they are washed out in the bulk limit. Below the critical density, at each pressure jump the shape of the liquid drop undergoes a morphological transition, changing from spherical to cylindrical to slablike as the density is increased. We formulate a simple theory of these shape transitions, which is adapted from a calculation originally developed by Binder and coworkers [L. G. MacDowell, P. Virnau, M. Muller, and K. Binder, J. Chem. Phys. 120, 5293 (2004), 10.1063/1.1645784]. Our focus is on the pressure equation of state (rather than on the chemical potential, as in the original work) and includes an extension to elongated boxes. Predictions based on this theory well agree with extensive Monte Carlo data for the cut-and-shifted Lennard-Jones fluid. We further discuss the thermodynamic stability of liquid drops with shapes other than the three mentioned above, like those found deep inside the liquid-vapor region in simulations starting from scratch. Our theory classifies these more elaborate shapes as metastable.

  11. IMPLEMENTATION OF THE SHEARING BOX APPROXIMATION IN ATHENA

    SciTech Connect

    Stone, James M.; Gardiner, Thomas A.

    2010-07-15

    We describe the implementation of the shearing box approximation for the study of the dynamics of accretion disks in the Athena magnetohydrodynamic (MHD) code. Second-order Crank-Nicholson time differencing is used for the Coriolis and tidal gravity source terms that appear in the momentum equation for accuracy and stability. We show that this approach conserves energy for epicyclic oscillations in hydrodynamic flows to round-off error. In the energy equation, the tidal gravity source terms are differenced as the gradient of an effective potential in a way that guarantees that total energy (including the gravitational potential energy) is also conserved to round-off error. We introduce an orbital advection algorithm for MHD based on constrained transport to preserve the divergence-free constraint on the magnetic field. This algorithm removes the orbital velocity from the time step constraint, and makes the truncation error more uniform in radial position. Modifications to the shearing box boundary conditions applied at the radial boundaries are necessary to conserve the total vertical magnetic flux. In principle, similar corrections are also required to conserve mass, momentum, and energy; however in practice we find that the orbital advection method conserves these quantities to better than 0.03% over hundreds of orbits. The algorithms have been applied to studies of the nonlinear regime of the MRI in very wide (up to 32 scale heights) horizontal domains.

  12. Shapes of a liquid droplet in a periodic box.

    PubMed

    Prestipino, Santi; Caccamo, Carlo; Costa, Dino; Malescio, Gianpietro; Munaò, Gianmarco

    2015-08-01

    Within the coexistence region between liquid and vapor the equilibrium pressure of a simulated fluid exhibits characteristic jumps and plateaus when plotted as a function of density at constant temperature. These features exclusively pertain to a finite-size sample in a periodic box, as they are washed out in the bulk limit. Below the critical density, at each pressure jump the shape of the liquid drop undergoes a morphological transition, changing from spherical to cylindrical to slablike as the density is increased. We formulate a simple theory of these shape transitions, which is adapted from a calculation originally developed by Binder and coworkers [L. G. MacDowell, P. Virnau, M. Muller, and K. Binder, J. Chem. Phys. 120, 5293 (2004)]. Our focus is on the pressure equation of state (rather than on the chemical potential, as in the original work) and includes an extension to elongated boxes. Predictions based on this theory well agree with extensive Monte Carlo data for the cut-and-shifted Lennard-Jones fluid. We further discuss the thermodynamic stability of liquid drops with shapes other than the three mentioned above, like those found deep inside the liquid-vapor region in simulations starting from scratch. Our theory classifies these more elaborate shapes as metastable. PMID:26382377

  13. Nearly Seamless Vacuum-Insulated Boxes

    NASA Technical Reports Server (NTRS)

    Stepanian, Christopher J.; Ou, Danny; Hu, Xiangjun

    2010-01-01

    A design concept, and a fabrication process that would implement the design concept, have been proposed for nearly seamless vacuum-insulated boxes that could be the main structural components of a variety of controlled-temperature containers, including common household refrigerators and insulating containers for shipping foods. In a typical case, a vacuum-insulated box would be shaped like a rectangular parallelepiped conventional refrigerator box having five fully closed sides and a hinged door on the sixth side. Although it is possible to construct the five-closed-side portion of the box as an assembly of five unitary vacuum-insulated panels, it is not desirable to do so because the relatively high thermal conductances of the seams between the panels would contribute significant amounts of heat leakage, relative to the leakage through the panels themselves. In contrast, the proposal would make it possible to reduce heat leakage by constructing the five-closed-side portion of the box plus the stationary portion (if any) of the sixth side as a single, seamless unit; the only remaining seam would be the edge seal around the door. The basic cross-sectional configuration of each side of a vacuum-insulated box according to the proposal would be that of a conventional vacuum-insulated panel: a low-density, porous core material filling a partially evacuated space between face sheets. However, neither the face sheets nor the core would be conventional. The face sheets would be opposite sides of a vacuum bag. The core material would be a flexible polymer-modified silica aerogel of the type described in Silica/Polymer and Silica/Polymer/Fiber Composite Aero - gels (MSC-23736) in this issue of NASA Tech Briefs. As noted in that article, the stiffness of this core material against compression is greater than that of prior aerogels. This is an important advantage because it translates to greater retention of thickness and, hence, of insulation performance when pressure is

  14. Advances in the theory of box integrals

    SciTech Connect

    Bailey, David H.; Borwein, J.M.; Crandall, R.E.

    2009-06-25

    Box integrals - expectations <|{rvec r}|{sup s}> or <|{rvec r}-{rvec q}|{sup s}> over the unit n-cube (or n-box) - have over three decades been occasionally given closed forms for isolated n,s. By employing experimental mathematics together with a new, global analytic strategy, we prove that for n {le} 4 dimensions the box integrals are for any integer s hypergeometrically closed in a sense we clarify herein. For n = 5 dimensions, we show that a single unresolved integral we call K{sub 5} stands in the way of such hyperclosure proofs. We supply a compendium of exemplary closed forms that naturally arise algorithmically from this theory.

  15. Box truss development and its application

    NASA Technical Reports Server (NTRS)

    Coyner, J. V.

    1985-01-01

    Since 1977, Martin Marietta Denver Aerospace has aggressively pursued development of deployable structural systems applicable to a wide variety of Shuttle-transportable large space system requirements. This effort has focused on the deployable box truss, mechanisms and materials development, mesh reflector design and fabrication, gate frame truss design and fabrication, and offset-fed antenna design and analysis. The activities discussed are: box truss design; metal matrix composites; precision joints; enhanced passive damping design; mesh reflector development; gate frame truss for solar arrays; 15-meter spinning radio meter; and 60 x 120 meter push broom antenna.

  16. CASAS: A Smart Home in a Box.

    PubMed

    Cook, Diane J; Crandall, Aaron S; Thomas, Brian L; Krishnan, Narayanan C

    2013-07-01

    While the potential benefits of smart home technology are widely recognized, a lightweight design is needed for the benefits to be realized at a large scale. We introduce the CASAS "smart home in a box", a lightweight smart home design that is easy to install and provides smart home capabilities out of the box with no customization or training. We discuss types of data analysis that have been performed by the CASAS group and can be pursued in the future by using this approach to designing and implementing smart home technologies.

  17. Box truss development and its application

    NASA Astrophysics Data System (ADS)

    Coyner, J. V.

    1985-04-01

    Since 1977, Martin Marietta Denver Aerospace has aggressively pursued development of deployable structural systems applicable to a wide variety of Shuttle-transportable large space system requirements. This effort has focused on the deployable box truss, mechanisms and materials development, mesh reflector design and fabrication, gate frame truss design and fabrication, and offset-fed antenna design and analysis. The activities discussed are: box truss design; metal matrix composites; precision joints; enhanced passive damping design; mesh reflector development; gate frame truss for solar arrays; 15-meter spinning radio meter; and 60 x 120 meter push broom antenna.

  18. Facile Atmospheric Pressure Synthesis of High Thermal Stability and Narrow-Band Red-Emitting SrLiAl3N4:Eu(2+) Phosphor for High Color Rendering Index White Light-Emitting Diodes.

    PubMed

    Zhang, Xuejie; Tsai, Yi-Ting; Wu, Shin-Mou; Lin, Yin-Chih; Lee, Jyh-Fu; Sheu, Hwo-Shuenn; Cheng, Bing-Ming; Liu, Ru-Shi

    2016-08-01

    Red phosphors (e.g., SrLiAl3N4:Eu(2+)) with high thermal stability and narrow-band properties are urgently explored to meet the next-generation high-power white light-emitting diodes (LEDs). However, to date, synthesis of such phosphors remains an arduous task. Herein, we report, for the first time, a facile method to synthesize SrLiAl3N4:Eu(2+) through Sr3N2, Li3N, Al, and EuN under atmospheric pressure. The as-synthesized narrow-band red-emitting phosphor exhibits excellent thermal stability, including small chromaticity shift and low thermal quenching. Intriguingly, the title phosphor shows an anomalous increase in theoretical lumen equivalent with the increase of temperature as a result of blue shift and band broadening of the emission band, which is crucial for high-power white LEDs. Utilizing the title phosphor, commercial YAG:Ce(3+), and InGaN-based blue LED chip, a proof-of-concept warm white LEDs with a color rendering index (CRI) of 91.1 and R9 = 68 is achieved. Therefore, our results highlight that this method, which is based on atmospheric pressure synthesis, may open a new means to explore narrow-band-emitting nitride phosphor. In addition, the underlying requirements to design Eu(2+)-doped narrow-band-emitting phosphors were also summarized. PMID:27403812

  19. Facile Atmospheric Pressure Synthesis of High Thermal Stability and Narrow-Band Red-Emitting SrLiAl3N4:Eu(2+) Phosphor for High Color Rendering Index White Light-Emitting Diodes.

    PubMed

    Zhang, Xuejie; Tsai, Yi-Ting; Wu, Shin-Mou; Lin, Yin-Chih; Lee, Jyh-Fu; Sheu, Hwo-Shuenn; Cheng, Bing-Ming; Liu, Ru-Shi

    2016-08-01

    Red phosphors (e.g., SrLiAl3N4:Eu(2+)) with high thermal stability and narrow-band properties are urgently explored to meet the next-generation high-power white light-emitting diodes (LEDs). However, to date, synthesis of such phosphors remains an arduous task. Herein, we report, for the first time, a facile method to synthesize SrLiAl3N4:Eu(2+) through Sr3N2, Li3N, Al, and EuN under atmospheric pressure. The as-synthesized narrow-band red-emitting phosphor exhibits excellent thermal stability, including small chromaticity shift and low thermal quenching. Intriguingly, the title phosphor shows an anomalous increase in theoretical lumen equivalent with the increase of temperature as a result of blue shift and band broadening of the emission band, which is crucial for high-power white LEDs. Utilizing the title phosphor, commercial YAG:Ce(3+), and InGaN-based blue LED chip, a proof-of-concept warm white LEDs with a color rendering index (CRI) of 91.1 and R9 = 68 is achieved. Therefore, our results highlight that this method, which is based on atmospheric pressure synthesis, may open a new means to explore narrow-band-emitting nitride phosphor. In addition, the underlying requirements to design Eu(2+)-doped narrow-band-emitting phosphors were also summarized.

  20. Synthesis and Behavior of Cetyltrimethyl Ammonium Bromide Stabilized Zn1+xSnO3+x (0 ≤ x ≤1) Nano-Crystallites

    PubMed Central

    Placke, Astrid; Kumar, Ashok; Priya, Shashank

    2016-01-01

    We report synthesis of cetyltrimethyl ammonium bromide (CTAB) stabilized Zn1+xSnO3+x (0 ≤ x ≤1) nano-crystallites by facile cost-effective wet chemistry route. The X-ray diffraction patterns of as-synthesized powders at the Zn/Sn ratio of 1 exhibited formation of ZnSn(OH)6. Increasing the Zn/Sn ratio further resulted in the precipitation of an additional phase corresponding to Zn(OH)2. The decomposition of these powders at 650°C for 3h led to the formation of the orthorhombic phase of ZnSnO3 and tetragonal SnO2-type phase of Zn2SnO4 at the Zn/Sn ratio of 1 and 2, respectively, with the formation of their mixed phases at intermediate compositions, i.e., at Zn/Sn ratio of 1.25, 1.50 and 1.75, respectively. The lattice parameters of orthorhombic and tetragonal phases were a ~ 3.6203 Å, b ~ 4.2646 Å and c ~ 12.8291Å (for ZnSnO3) and a = b ~ 5.0136 Å and c ~ 3.3055Å (for Zn2SnO4). The transmission electron micrographs revealed the formation of nano-crystallites with aspect ratio ~ 2; the length and thickness being 24, 13 nm (for ZnSnO3) and 47, 22 nm (for Zn2SnO4), respectively. The estimated direct bandgap values for the ZnSnO3 and Zn2SnO4 were found to be 4.21 eV and 4.12 eV, respectively. The ac conductivity values at room temperature (at 10 kHz) for the ZnSnO3 and Zn2SnO4 samples were 8.02 × 10−8 Ω-1 cm-1 and 6.77 × 10−8 Ω-1 cm-1, respectively. The relative permittivity was found to increase with increase in temperature, the room temperature values being 14.24 and 25.22 for the samples ZnSnO3 and Zn2SnO4, respectively. Both the samples, i.e., ZnSnO3 and Zn2SnO4, exhibited low values of loss tangent up to 300 K, the room temperature values being 0.89 and 0.72, respectively. A dye-sensitized solar cell has been fabricated using the optimized sample of zinc stannate photo-anode, i.e., Zn2SnO4. The cyclic voltammetry revealed oxidation and reduction around 0.40 V (current density ~ 11.1 mA/cm2) and 0.57 V (current density– 11.7 mA/cm2) for Zn2SnO4

  1. Synthesis and Behavior of Cetyltrimethyl Ammonium Bromide Stabilized Zn1+xSnO3+x (0 ≤ x ≤1) Nano-Crystallites.

    PubMed

    Placke, Astrid; Kumar, Ashok; Priya, Shashank

    2016-01-01

    We report synthesis of cetyltrimethyl ammonium bromide (CTAB) stabilized Zn1+xSnO3+x (0 ≤ x ≤1) nano-crystallites by facile cost-effective wet chemistry route. The X-ray diffraction patterns of as-synthesized powders at the Zn/Sn ratio of 1 exhibited formation of ZnSn(OH)6. Increasing the Zn/Sn ratio further resulted in the precipitation of an additional phase corresponding to Zn(OH)2. The decomposition of these powders at 650°C for 3h led to the formation of the orthorhombic phase of ZnSnO3 and tetragonal SnO2-type phase of Zn2SnO4 at the Zn/Sn ratio of 1 and 2, respectively, with the formation of their mixed phases at intermediate compositions, i.e., at Zn/Sn ratio of 1.25, 1.50 and 1.75, respectively. The lattice parameters of orthorhombic and tetragonal phases were a ~ 3.6203 Å, b ~ 4.2646 Å and c ~ 12.8291Å (for ZnSnO3) and a = b ~ 5.0136 Å and c ~ 3.3055Å (for Zn2SnO4). The transmission electron micrographs revealed the formation of nano-crystallites with aspect ratio ~ 2; the length and thickness being 24, 13 nm (for ZnSnO3) and 47, 22 nm (for Zn2SnO4), respectively. The estimated direct bandgap values for the ZnSnO3 and Zn2SnO4 were found to be 4.21 eV and 4.12 eV, respectively. The ac conductivity values at room temperature (at 10 kHz) for the ZnSnO3 and Zn2SnO4 samples were 8.02 × 10-8 Ω-1 cm-1 and 6.77 × 10-8 Ω-1 cm-1, respectively. The relative permittivity was found to increase with increase in temperature, the room temperature values being 14.24 and 25.22 for the samples ZnSnO3 and Zn2SnO4, respectively. Both the samples, i.e., ZnSnO3 and Zn2SnO4, exhibited low values of loss tangent up to 300 K, the room temperature values being 0.89 and 0.72, respectively. A dye-sensitized solar cell has been fabricated using the optimized sample of zinc stannate photo-anode, i.e., Zn2SnO4. The cyclic voltammetry revealed oxidation and reduction around 0.40 V (current density ~ 11.1 mA/cm2) and 0.57 V (current density- 11.7 mA/cm2) for Zn2SnO4 photo

  2. 30 CFR 56.12006 - Distribution boxes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distribution boxes. 56.12006 Section 56.12006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity §...

  3. 30 CFR 56.12006 - Distribution boxes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Distribution boxes. 56.12006 Section 56.12006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity §...

  4. 30 CFR 56.12006 - Distribution boxes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Distribution boxes. 56.12006 Section 56.12006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity §...

  5. 30 CFR 57.12006 - Distribution boxes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Distribution boxes. 57.12006 Section 57.12006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Electricity...

  6. 30 CFR 56.12006 - Distribution boxes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Distribution boxes. 56.12006 Section 56.12006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity §...

  7. 30 CFR 57.12006 - Distribution boxes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Distribution boxes. 57.12006 Section 57.12006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Electricity...

  8. 30 CFR 56.12006 - Distribution boxes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Distribution boxes. 56.12006 Section 56.12006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity §...

  9. Cereal Box Design: An Interdisciplinary Graphics Activity

    ERIC Educational Resources Information Center

    Fitzgerald, Mike; Tsosie, Teri

    2012-01-01

    The cereal box design activity is intriguing both for its simplicity and the resourcefulness that it can generate in young people. Also, it lends itself to a variety of curriculums. It covers both consumerism and Design for the Environment (DfE) concepts broadly and in depth. The activity introduces a wide range of topics. They include graphic…

  10. Nest Boxes Artificial Homes for Woodland Mammals.

    ERIC Educational Resources Information Center

    Decker, Daniel J.; Kelley, John W.

    1983-01-01

    Provides instructions for constructing artificial "homes" for squirrels, raccoons, and rabbits. These include squirrel dens constructed from discarded automobile tires and squirrel nest boxes, raccoon dens, and rabbit burrows constructed from wood. Includes a chart giving dimensions of materials needed and suggestions on where to place the…

  11. One-Dimensional Oscillator in a Box

    ERIC Educational Resources Information Center

    Amore, Paolo; Fernandez, Francisco M.

    2010-01-01

    We discuss a quantum-mechanical model of two particles that interact by means of a harmonic potential and are confined to a one-dimensional box with impenetrable walls. We apply perturbation theory to the cases of different and equal masses and analyse the symmetry of the states in the latter case. We compare the approximate perturbation results…

  12. The "Build-the-Box" Lesson.

    ERIC Educational Resources Information Center

    Penrose, John M.

    2000-01-01

    Describes a "build-the-box" lesson to develop a better understanding of writing useful and effective instructions. Considers how the lack of instruction with this assignment compels students to think creatively to complete the project. Concludes that many students realize the difficulty in creating easy-to-understand instructions. Enhances the…

  13. Library Technology: The Black Box Syndrome.

    ERIC Educational Resources Information Center

    Stevens, Norman

    1983-01-01

    Presents overview of library uses of automation, noting the earliest example of a "black box" in 1588, the "indicator" invented in England in 1863, various forms of card catalogs, and computer solutions posed by Vannevar Bush, J. C. R. Licklider, Project Intrex, and John G. Kemeny. Ten references are cited. (EJS)

  14. Hazard Analysis of Japanese Boxed Lunches (Bento).

    ERIC Educational Resources Information Center

    Bryan, Frank L.; And Others

    1991-01-01

    For the purposes of identifying contaminants, of assessing risks, and of determining critical food processing control points, hazard analyses were conducted at two "bento" (oriental boxed meals) catering operations. Time and temperature abuses during the holding period, after cooking and prior to consumption, were found to be the primary reason…

  15. Using Story Boxes in Language Learning

    ERIC Educational Resources Information Center

    Collins, Rita

    2009-01-01

    Story boxes and story bags are containers for holding realia that are used to enhance reading and provide a variety of activities for encouraging language acquisition and use. Whatever the packaging, these are good ways to develop students' interest in books. Using realia, or real-life objects, to teach a foreign language is not a novel concept.…

  16. Nondestructive assay of boxed radioactive waste

    SciTech Connect

    Gilles, W.P.; Roberts, R.J.; Jasen, W.G.

    1992-12-01

    This paper describes the problems related to the nondestructive assay (NDA) of boxed radioactive waste at the Hanford Site and how Westinghouse Hanford company (WHC) is solving the problems. The waste form and radionuclide content are described. The characteristics of the combined neutron and gamma-based measurement system are described.

  17. Argon purge gas cooled by chill box

    NASA Technical Reports Server (NTRS)

    Spiro, L. W.

    1966-01-01

    Cooling argon purge gas by routing it through a shop-fabricated chill box reduces charring of tungsten inert gas torch head components. The argon gas is in a cooled state as it enters the torch and prevents buildup of char caused by the high concentrations of heat in the weld area during welding operations.

  18. 46 CFR 111.81-1 - Outlet boxes and junction boxes; general.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... standards, all of which are incorporated by reference (see 46 CFR 110.10-1): Article 314 of NFPA NEC 2002... junction box must have a cover unless a fixture canopy, switch cover, receptacle cover, or other cover...

  19. 46 CFR 111.81-1 - Outlet boxes and junction boxes; general.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... standards, all of which are incorporated by reference (see 46 CFR 110.10-1): Article 314 of NFPA NEC 2002... junction box must have a cover unless a fixture canopy, switch cover, receptacle cover, or other cover...

  20. Egg-Box Structure in Cobalt Alginate: A New Approach to Multifunctional Hierarchical Mesoporous N-Doped Carbon Nanofibers for Efficient Catalysis and Energy Storage

    PubMed Central

    2015-01-01

    Carbon nanomaterials with both doped heteroatom and porous structure represent a new class of carbon nanostructures for boosting electrochemical application, particularly sustainable electrochemical energy conversion and storage applications. We herein demonstrate a unique large-scale sustainable biomass conversion strategy for the synthesis of earth-abundant multifunctional carbon nanomaterials with well-defined doped heteroatom level and multimodal pores through pyrolyzing electrospinning renewable natural alginate. The key part for our chemical synthesis is that we found that the egg-box structure in cobalt alginate nanofiber can offer new opportunity to create large mesopores (∼10–40 nm) on the surface of nitrogen-doped carbon nanofibers. The as-prepared hierarchical carbon nanofibers with three-dimensional pathway for electron and ion transport are conceptually new as high-performance multifunctional electrochemical materials for boosting the performance of oxygen reduction reaction (ORR), lithium ion batteries (LIBs), and supercapacitors (SCs). In particular, they show amazingly the same ORR activity as commercial Pt/C catalyst and much better long-term stability and methanol tolerance for ORR than Pt/C via a four-electron pathway in alkaline electrolyte. They also exhibit a large reversible capacity of 625 mAh g–1 at 1 A g–1, good rate capability, and excellent cycling performance for LIBs, making them among the best in all the reported carbon nanomaterials. They also represent highly efficient carbon nanomaterials for SCs with excellent capacitive behavior of 197 F g–1 at 1 A g–1 and superior stability. The present work highlights the importance of biomass-derived multifunctional mesoporous carbon nanomaterials in enhancing electrochemical catalysis and energy storage. PMID:27162980

  1. Egg-Box Structure in Cobalt Alginate: A New Approach to Multifunctional Hierarchical Mesoporous N-Doped Carbon Nanofibers for Efficient Catalysis and Energy Storage.

    PubMed

    Li, Daohao; Lv, Chunxiao; Liu, Long; Xia, Yanzhi; She, Xilin; Guo, Shaojun; Yang, Dongjiang

    2015-08-26

    Carbon nanomaterials with both doped heteroatom and porous structure represent a new class of carbon nanostructures for boosting electrochemical application, particularly sustainable electrochemical energy conversion and storage applications. We herein demonstrate a unique large-scale sustainable biomass conversion strategy for the synthesis of earth-abundant multifunctional carbon nanomaterials with well-defined doped heteroatom level and multimodal pores through pyrolyzing electrospinning renewable natural alginate. The key part for our chemical synthesis is that we found that the egg-box structure in cobalt alginate nanofiber can offer new opportunity to create large mesopores (∼10-40 nm) on the surface of nitrogen-doped carbon nanofibers. The as-prepared hierarchical carbon nanofibers with three-dimensional pathway for electron and ion transport are conceptually new as high-performance multifunctional electrochemical materials for boosting the performance of oxygen reduction reaction (ORR), lithium ion batteries (LIBs), and supercapacitors (SCs). In particular, they show amazingly the same ORR activity as commercial Pt/C catalyst and much better long-term stability and methanol tolerance for ORR than Pt/C via a four-electron pathway in alkaline electrolyte. They also exhibit a large reversible capacity of 625 mAh g(-1) at 1 A g(-1), good rate capability, and excellent cycling performance for LIBs, making them among the best in all the reported carbon nanomaterials. They also represent highly efficient carbon nanomaterials for SCs with excellent capacitive behavior of 197 F g(-1) at 1 A g(-1) and superior stability. The present work highlights the importance of biomass-derived multifunctional mesoporous carbon nanomaterials in enhancing electrochemical catalysis and energy storage. PMID:27162980

  2. 25. Emplacement no. 1, view to southwest in terminal box ...

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

    25. Emplacement no. 1, view to southwest in terminal box room, showing terminal box; largest of the cables extends to gun platform - Fort Wadsworth Battery Romeyn B. Ayers, South side of Ayers Road, Staten Island, Rosebank, Richmond County, NY

  3. 8. View looking east at the west end of box ...

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

    8. View looking east at the west end of box for Siphon 1. Typical concrete siphon box. - Lake Hodges Flume, Along San Dieguito River between Lake Hodges & San Dieguito Reservoir, Rancho Santa Fe, San Diego County, CA

  4. The Box Turtle: Room with a View on Species Decline.

    ERIC Educational Resources Information Center

    Belzer, Bill; Steisslinger, Mary Beth

    1999-01-01

    Surveys salient aspects of eastern box-turtle natural history. Explores the societal and ecological factors that have contributed to the decline of the box-turtle population. Contains 18 references. (WRM)

  5. 22. Steering gear box and wheel from starboard side. Mizzen ...

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

    22. Steering gear box and wheel from starboard side. Mizzen boom has been removed for repairs (note boom cradle just forward of steering gear box). - Schooner C.A. THAYER, Hyde Street Pier, San Francisco, San Francisco County, CA

  6. 24. A CORE WORKER DISPLAYS THE CORE BOX AND CORES ...

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

    24. A CORE WORKER DISPLAYS THE CORE BOX AND CORES FOR A BRASS GATE VALVE BODY MADE ON A CORE BOX, CA. 1950. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  7. 7. Process areas room. Incinerator and glove boxes (hoods) to ...

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

    7. Process areas room. Incinerator and glove boxes (hoods) to the right. Filter boxes to the left. Looking south. - Plutonium Finishing Plant, Waste Incinerator Facility, 200 West Area, Richland, Benton County, WA

  8. Ballast system for maintaining constant pressure in a glove box

    NASA Technical Reports Server (NTRS)

    Shlichta, Paul J. (Inventor)

    1989-01-01

    A ballast system is disclosed for a glove box including a fixed platform on which is mounted an inflatable bag on top of which resides a cover and a weight. The variable gas volume of the inflatable bag communicates with that of the glove box via a valved tube. The weight and the gas volume are selected to maintain a relatively constant pressure in the glove box despite variations in the glove box volume while avoiding the use of complicated valving apparatus.

  9. Ballast system for maintaining constant pressure in a glove box

    NASA Technical Reports Server (NTRS)

    Shlichta, Paul J. (Inventor)

    1990-01-01

    A ballast system for a glove box including a fixed platform on which is mounted an inflatable bag on top of which resides a cover and a weight. The variable gas volume of the inflatable bag communicates with that of the glove box via a valved tube. The weight and gas volume are selected to maintain a relatively constant pressure in the glove box despite variations in the glove box volume while avoiding the use of complicated valving apparatus.

  10. Effects of dominant material properties on the stability and transport of TiO2 nanoparticles and carbon nanotubes in aquatic environment: From synthesis to fate

    EPA Science Inventory

    Recently, increasing studies have focused on the environment stability, transport, and fate of the anthropogenic nanomaterials in the environment, which contributes to the understanding of the potential risks when released. However, applying nanomaterials from different manufactu...

  11. 30 CFR 18.49 - Connection boxes on machines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Connection boxes on machines. 18.49 Section 18... Design Requirements § 18.49 Connection boxes on machines. Connection boxes used to facilitate replacement of cables or machine components shall be explosion-proof. Portable-cable terminals on cable...

  12. 30 CFR 18.49 - Connection boxes on machines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Connection boxes on machines. 18.49 Section 18... Design Requirements § 18.49 Connection boxes on machines. Connection boxes used to facilitate replacement of cables or machine components shall be explosion-proof. Portable-cable terminals on cable...

  13. 30 CFR 18.49 - Connection boxes on machines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Connection boxes on machines. 18.49 Section 18... Design Requirements § 18.49 Connection boxes on machines. Connection boxes used to facilitate replacement of cables or machine components shall be explosion-proof. Portable-cable terminals on cable...

  14. 30 CFR 18.49 - Connection boxes on machines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Connection boxes on machines. 18.49 Section 18... Design Requirements § 18.49 Connection boxes on machines. Connection boxes used to facilitate replacement of cables or machine components shall be explosion-proof. Portable-cable terminals on cable...

  15. 30 CFR 18.49 - Connection boxes on machines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Connection boxes on machines. 18.49 Section 18... Design Requirements § 18.49 Connection boxes on machines. Connection boxes used to facilitate replacement of cables or machine components shall be explosion-proof. Portable-cable terminals on cable...

  16. 49 CFR 178.515 - Standards for reconstituted wood boxes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Standards for reconstituted wood boxes. 178.515... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.515 Standards for reconstituted wood boxes. (a) The identification code for a reconstituted wood box is 4F. (b) Construction requirements...

  17. 49 CFR 178.515 - Standards for reconstituted wood boxes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Standards for reconstituted wood boxes. 178.515... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.515 Standards for reconstituted wood boxes. (a) The identification code for a reconstituted wood box is 4F. (b) Construction requirements...

  18. 49 CFR 215.107 - Defective plain bearing box: General.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Defective plain bearing box: General. 215.107... Suspension System § 215.107 Defective plain bearing box: General. A railroad may not place or continue in service a car, if the car has— (a) A plain bearing box that does not contain visible free oil; (b) A...

  19. 49 CFR 215.107 - Defective plain bearing box: General.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Defective plain bearing box: General. 215.107... Suspension System § 215.107 Defective plain bearing box: General. A railroad may not place or continue in service a car, if the car has— (a) A plain bearing box that does not contain visible free oil; (b) A...

  20. 49 CFR 215.107 - Defective plain bearing box: General.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Defective plain bearing box: General. 215.107... Suspension System § 215.107 Defective plain bearing box: General. A railroad may not place or continue in service a car, if the car has— (a) A plain bearing box that does not contain visible free oil; (b) A...

  1. 49 CFR 230.102 - Tender plain bearing journal boxes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Tender plain bearing journal boxes. 230.102... Locomotives and Tenders Running Gear § 230.102 Tender plain bearing journal boxes. Plain bearing journal boxes... expected to damage the bearing; or have a detrimental effect on the lubrication of the journal and...

  2. 49 CFR 215.107 - Defective plain bearing box: General.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Defective plain bearing box: General. 215.107... Suspension System § 215.107 Defective plain bearing box: General. A railroad may not place or continue in service a car, if the car has— (a) A plain bearing box that does not contain visible free oil; (b) A...

  3. 49 CFR 215.107 - Defective plain bearing box: General.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Defective plain bearing box: General. 215.107... Suspension System § 215.107 Defective plain bearing box: General. A railroad may not place or continue in service a car, if the car has— (a) A plain bearing box that does not contain visible free oil; (b) A...

  4. 30 CFR 18.43 - Explosion-proof splice boxes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Explosion-proof splice boxes. 18.43 Section 18... Design Requirements § 18.43 Explosion-proof splice boxes. Internal connections shall be rigidly held and adequately insulated. Strain clamps shall be provided for all cables entering a splice box....

  5. 46 CFR 113.20-3 - Connection boxes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 4X of NEMA 250 or IP 56 of IEC 60529 (both incorporated by reference; see 46 CFR 110.10-1... 46 Shipping 4 2010-10-01 2010-10-01 false Connection boxes. 113.20-3 Section 113.20-3 Shipping... SYSTEMS AND EQUIPMENT Automatic Sprinkler Systems § 113.20-3 Connection boxes. Each connection box...

  6. 30 CFR 18.43 - Explosion-proof splice boxes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Explosion-proof splice boxes. 18.43 Section 18... Design Requirements § 18.43 Explosion-proof splice boxes. Internal connections shall be rigidly held and adequately insulated. Strain clamps shall be provided for all cables entering a splice box....

  7. 30 CFR 18.42 - Explosion-proof distribution boxes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Explosion-proof distribution boxes. 18.42... and Design Requirements § 18.42 Explosion-proof distribution boxes. (a) A cable passing through an outside wall(s) of a distribution box shall be conducted either through a packing gland or an...

  8. 30 CFR 18.42 - Explosion-proof distribution boxes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Explosion-proof distribution boxes. 18.42... and Design Requirements § 18.42 Explosion-proof distribution boxes. (a) A cable passing through an outside wall(s) of a distribution box shall be conducted either through a packing gland or an...

  9. 30 CFR 18.43 - Explosion-proof splice boxes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Explosion-proof splice boxes. 18.43 Section 18... Design Requirements § 18.43 Explosion-proof splice boxes. Internal connections shall be rigidly held and adequately insulated. Strain clamps shall be provided for all cables entering a splice box....

  10. 77 FR 42342 - Post Office Box Service Enhancements

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-18

    ... Post Office Box Service Enhancements AGENCY: Postal Regulatory Commission. ACTION: Notice. SUMMARY: The... certain competitive post office box locations. This notice addresses procedural steps associated with the... introduction of enhanced services that it offers to post office box customers at certain retail...

  11. 30 CFR 57.12007 - Junction box connection procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Junction box connection procedures. 57.12007... Electricity Surface and Underground § 57.12007 Junction box connection procedures. Trailing cable and power-cable connections to junction boxes shall not be made or broken under load....

  12. 30 CFR 18.42 - Explosion-proof distribution boxes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Explosion-proof distribution boxes. 18.42... and Design Requirements § 18.42 Explosion-proof distribution boxes. (a) A cable passing through an outside wall(s) of a distribution box shall be conducted either through a packing gland or an...

  13. 30 CFR 18.43 - Explosion-proof splice boxes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Explosion-proof splice boxes. 18.43 Section 18... Design Requirements § 18.43 Explosion-proof splice boxes. Internal connections shall be rigidly held and adequately insulated. Strain clamps shall be provided for all cables entering a splice box....

  14. 30 CFR 18.42 - Explosion-proof distribution boxes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Explosion-proof distribution boxes. 18.42... and Design Requirements § 18.42 Explosion-proof distribution boxes. (a) A cable passing through an outside wall(s) of a distribution box shall be conducted either through a packing gland or an...

  15. 30 CFR 57.12007 - Junction box connection procedures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Junction box connection procedures. 57.12007... Electricity Surface and Underground § 57.12007 Junction box connection procedures. Trailing cable and power-cable connections to junction boxes shall not be made or broken under load....

  16. 77 FR 36585 - Post Office Box Service Enhancements

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-19

    ... COMMISSION Post Office Box Service Enhancements AGENCY: Postal Regulatory Commission. ACTION: Notice. SUMMARY... concerning enhanced services for Post Office Box service. It also addresses the status of a related Complaint... enhanced services that it offers to post office box customers at certain retail locations.\\1\\ The...

  17. 46 CFR 113.20-3 - Connection boxes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 4X of NEMA 250 or IP 56 of IEC 60529 (both incorporated by reference; see 46 CFR 110.10-1... 46 Shipping 4 2014-10-01 2014-10-01 false Connection boxes. 113.20-3 Section 113.20-3 Shipping... SYSTEMS AND EQUIPMENT Automatic Sprinkler Systems § 113.20-3 Connection boxes. Each connection box...

  18. 30 CFR 57.12007 - Junction box connection procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Junction box connection procedures. 57.12007... Electricity Surface and Underground § 57.12007 Junction box connection procedures. Trailing cable and power-cable connections to junction boxes shall not be made or broken under load....

  19. 46 CFR 113.20-3 - Connection boxes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 4X of NEMA 250 or IP 56 of IEC 60529 (both incorporated by reference; see 46 CFR 110.10-1... 46 Shipping 4 2013-10-01 2013-10-01 false Connection boxes. 113.20-3 Section 113.20-3 Shipping... SYSTEMS AND EQUIPMENT Automatic Sprinkler Systems § 113.20-3 Connection boxes. Each connection box...

  20. 46 CFR 113.20-3 - Connection boxes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 4X of NEMA 250 or IP 56 of IEC 60529 (both incorporated by reference; see 46 CFR 110.10-1... 46 Shipping 4 2012-10-01 2012-10-01 false Connection boxes. 113.20-3 Section 113.20-3 Shipping... SYSTEMS AND EQUIPMENT Automatic Sprinkler Systems § 113.20-3 Connection boxes. Each connection box...

  1. 30 CFR 18.42 - Explosion-proof distribution boxes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Explosion-proof distribution boxes. 18.42... and Design Requirements § 18.42 Explosion-proof distribution boxes. (a) A cable passing through an outside wall(s) of a distribution box shall be conducted either through a packing gland or an...

  2. 30 CFR 57.12007 - Junction box connection procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Junction box connection procedures. 57.12007... Electricity Surface and Underground § 57.12007 Junction box connection procedures. Trailing cable and power-cable connections to junction boxes shall not be made or broken under load....

  3. 46 CFR 113.20-3 - Connection boxes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 4X of NEMA 250 or IP 56 of IEC 60529 (both incorporated by reference; see 46 CFR 110.10-1... 46 Shipping 4 2011-10-01 2011-10-01 false Connection boxes. 113.20-3 Section 113.20-3 Shipping... SYSTEMS AND EQUIPMENT Automatic Sprinkler Systems § 113.20-3 Connection boxes. Each connection box...

  4. 30 CFR 18.43 - Explosion-proof splice boxes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Explosion-proof splice boxes. 18.43 Section 18... Design Requirements § 18.43 Explosion-proof splice boxes. Internal connections shall be rigidly held and adequately insulated. Strain clamps shall be provided for all cables entering a splice box....

  5. 30 CFR 57.12007 - Junction box connection procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Junction box connection procedures. 57.12007... Electricity Surface and Underground § 57.12007 Junction box connection procedures. Trailing cable and power-cable connections to junction boxes shall not be made or broken under load....

  6. 49 CFR 230.103 - Tender roller bearing journal boxes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Tender roller bearing journal boxes. 230.103... Locomotives and Tenders Running Gear § 230.103 Tender roller bearing journal boxes. Tender roller bearing journal boxes shall be maintained in a safe and suitable condition....

  7. Transformative Environmental Education: Stepping Outside the Curriculum Box

    ERIC Educational Resources Information Center

    Johnston, Julie

    2009-01-01

    Environmental education has become trapped in the curriculum box. At a time when our students' generation is becoming trapped in a global warming box, their education needs to be rapidly adaptable to the changing state of their planet. Venturing outside the curriculum box takes courage, creativity, and a willingness to let nature serve as the…

  8. 49 CFR 178.515 - Standards for reconstituted wood boxes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Standards for reconstituted wood boxes. 178.515... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.515 Standards for reconstituted wood boxes. (a) The identification code for a reconstituted wood box is 4F. (b) Construction requirements...

  9. 31 CFR 515.326 - Custody of safe deposit boxes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Custody of safe deposit boxes. 515.326 Section 515.326 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... Definitions § 515.326 Custody of safe deposit boxes. Safe deposit boxes shall be deemed to be in the...

  10. 31 CFR 500.326 - Custody of safe deposit boxes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Custody of safe deposit boxes. 500.326 Section 500.326 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Definitions § 500.326 Custody of safe deposit boxes. Safe deposit boxes shall be deemed to be in the...

  11. 31 CFR 515.326 - Custody of safe deposit boxes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Custody of safe deposit boxes. 515.326 Section 515.326 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... Definitions § 515.326 Custody of safe deposit boxes. Safe deposit boxes shall be deemed to be in the...

  12. 31 CFR 515.326 - Custody of safe deposit boxes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Custody of safe deposit boxes. 515.326 Section 515.326 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... Definitions § 515.326 Custody of safe deposit boxes. Safe deposit boxes shall be deemed to be in the...

  13. 31 CFR 515.326 - Custody of safe deposit boxes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Custody of safe deposit boxes. 515.326 Section 515.326 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Definitions § 515.326 Custody of safe deposit boxes. Safe deposit boxes shall be deemed to be in the...

  14. 31 CFR 515.326 - Custody of safe deposit boxes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Custody of safe deposit boxes. 515.326 Section 515.326 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... Definitions § 515.326 Custody of safe deposit boxes. Safe deposit boxes shall be deemed to be in the...

  15. Clocks, Cameras, and Chatter, Chatter, Chatter: Activity Boxes as Curriculum.

    ERIC Educational Resources Information Center

    Suskind, Diane; Kittel, Jeanie

    1989-01-01

    Describes activity boxes which can be used in early childhood classrooms to further curriculum and development goals. Activity boxes are containers filled with related objects categorized by color, shape, or material which encourage children to explore, sort, and manipulate real things. Discusses goals and lists contents for 24 activity boxes.…

  16. Using Origami Boxes to Explore Concepts of Geometry and Calculus

    ERIC Educational Resources Information Center

    Wares, Arsalan

    2011-01-01

    The purpose of this classroom note is to provide an example of how a simple origami box can be used to explore important concepts of geometry and calculus. This article describes how an origami box can be folded, then it goes on to describe how its volume and surface area can be calculated. Finally, it describes how the box could be folded to…

  17. 49 CFR 230.104 - Driving box shoes and wedges.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Driving box shoes and wedges. 230.104 Section 230.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Locomotives and Tenders Running Gear § 230.104 Driving box shoes and wedges. Driving box shoes and...

  18. 49 CFR 230.104 - Driving box shoes and wedges.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Driving box shoes and wedges. 230.104 Section 230.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Locomotives and Tenders Running Gear § 230.104 Driving box shoes and wedges. Driving box shoes and...

  19. 49 CFR 230.104 - Driving box shoes and wedges.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Driving box shoes and wedges. 230.104 Section 230.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Locomotives and Tenders Running Gear § 230.104 Driving box shoes and wedges. Driving box shoes and...

  20. 49 CFR 230.104 - Driving box shoes and wedges.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Driving box shoes and wedges. 230.104 Section 230.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Locomotives and Tenders Running Gear § 230.104 Driving box shoes and wedges. Driving box shoes and...